tetracycline and Disease-Models--Animal

Nonalcoholic fatty liver disease (NAFLD) is a continuous diseases spectrum associated with obesity, type 2 diabetes, insulin resistance, and hyperlipidemia. Simple hepatic steatosis may progress to nonalcoholic steatohepatitis (NASH), even fibrosis and cirrhosis, and finally hepatocellular carcinoma. In recent years, NAFLD has become a public health concern with increasing prevalence. However, the mechanisms underlying the pathogenesis remain incompletely understood, and few effective therapeutic approaches are available. Summary and Key Messages: A myriad of different rodent models has been developed to elucidate pathophysiology of NAFLD/NASH and guide therapeutic strategy. To date, no single rodent model can display the whole disease spectrum and metabolic features associated with human NASH, but can imitate particular characteristics. In this paper, we review the most commonly used dietary, genetic, and chemical rodent models for NAFLD referring to their advantages and disadvantages. Also, we illustrate the status of latest treatment strategy using various NAFLD rodent models. We hope to provide critical guidance for researchers to select appropriate animal models.

Topics: Animals; Antioxidants; Carbon Tetrachloride; Cholesterol, Dietary; Combined Modality Therapy; Diet, Carbohydrate Loading; Diet, High-Fat; Disease Models, Animal; Fecal Microbiota Transplantation; Gastrointestinal Microbiome; Humans; Insulin; Lipid Metabolism; Liver; Liver Cirrhosis; Mice; Mice, Knockout; Mice, Obese; Non-alcoholic Fatty Liver Disease; Probiotics; Rats; Rats, Transgenic; Streptozocin; Tetracycline

Patients with POAG have lower corneal endothelial cell density than healthy controls of the same age. This may be attributed to mechanical damage from elevated IOP and toxicity of glaucoma medications.. Mycophenolic acid was detected in all cats. The dose 10 mg/kg given q12h for 1 week was tolerated (n = 3). The efficacy of MMF as an immunosuppressant and long-term safety in cats of this dosage regimen is unknown.. T

Topics: Acetylcholine; Acinetobacter baumannii; Actinobacteria; Action Potentials; Adalimumab; Adaptation, Physiological; Adipates; Administration, Oral; Adolescent; Adrenal Glands; Adsorption; Adult; Aged; Aged, 80 and over; Aging; AIDS-Related Opportunistic Infections; Aldosterone; Amino Acids; Ammonia; Amoxicillin; AMP-Activated Protein Kinases; Animals; Antacids; Anti-Bacterial Agents; Antineoplastic Agents; Antirheumatic Agents; Apgar Score; Area Under Curve; ARNTL Transcription Factors; Arterial Pressure; Arthritis, Juvenile; Athletes; Attention; Biodegradation, Environmental; Biofilms; Biofuels; Biological Therapy; Biomass; Biomimetic Materials; Bioreactors; Birth Weight; Bismuth; Blood Flow Velocity; Bone and Bones; Brain Injuries, Traumatic; Calcium; Calcium Channels; Capsaicin; Carbon; Carcinoma, Hepatocellular; Cardiomegaly, Exercise-Induced; Cartilage; Cartilage, Articular; Case-Control Studies; Catalysis; Cats; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cell Death; Cell Differentiation; Cell Line, Tumor; Cell Membrane; Charcoal; Chemokine CCL2; Child; Child, Preschool; Chondrogenesis; Chronic Disease; Circadian Clocks; Circadian Rhythm Signaling Peptides and Proteins; Clarithromycin; Coccidioides; Coccidioidomycosis; Cognitive Behavioral Therapy; Coinfection; Color; Coloring Agents; Computer Simulation; Computers, Molecular; Consensus; Corticosterone; Cyclic AMP Response Element-Binding Protein; Cytochrome P-450 Enzyme System; Death, Sudden, Cardiac; Density Functional Theory; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Dialysis Solutions; Disease Models, Animal; Dogs; Dopamine Agonists; Dose-Response Relationship, Drug; Doxorubicin; Drug Administration Schedule; Drug Resistance, Bacterial; Drug Therapy, Combination; Electrocardiography; Electrocardiography, Ambulatory; Electrolytes; Endocardium; Endocrine Disruptors; Endocytosis; Endoscopy, Gastrointestinal; Escherichia coli Proteins; Esters; Evolution, Molecular; Executive Function; Feasibility Studies; Female; Ferric Compounds; Fluorescence; Fluorescent Dyes; Fluorine Radioisotopes; Frailty; Free Radical Scavengers; Gabapentin; Geriatric Assessment; Glucaric Acid; Glucocorticoids; Glucose; Glucose Metabolism Disorders; Halogenated Diphenyl Ethers; Heart Rate; Heart Ventricles; HEK293 Cells; Helicobacter Infections; Helicobacter pylori; Hep G2 Cells; Hepatocytes; Humans; Hungary; Hydrogen Sulfide; Hydrogen-Ion Concentration; Immunologic Factors; Immunomodulation; Immunosuppressive Agents; Independent Living; Indocyanine Green; Infant; Infant Formula; Infant Mortality; Infant, Newborn; Infant, Newborn, Diseases; Inflorescence; Insulin Resistance; Insulins; International Agencies; Iron; Isotonic Solutions; Kidney Failure, Chronic; Kinetics; Lactones; Leukocytes, Mononuclear; Liver Neoplasms; Macular Edema; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Magnetosomes; Male; Medical Audit; Mesenchymal Stem Cells; Metabolic Syndrome; Metformin; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Nude; Middle Aged; Molecular Conformation; Molecular Targeted Therapy; Motor Activity; Multiple Sclerosis; Mycophenolic Acid; Netherlands; Neuropsychological Tests; Nuclear Energy; Organs at Risk; Osteoarthritis; Osteoarthritis, Hip; Oxidation-Reduction; Palladium; Pericardium; Perinatal Death; Peritoneal Dialysis; Phantoms, Imaging; Pharmaceutical Preparations; Phospholipids; Phosphorylation; Physical Conditioning, Human; Physical Endurance; Pilot Projects; Polyketides; Polymers; Positron-Emission Tomography; Postoperative Period; Potassium; Powders; Pramipexole; Predictive Value of Tests; Pregabalin; Pregnancy; Pregnancy Outcome; Protein Structure, Secondary; Proton Pump Inhibitors; Puberty; Pulmonary Circulation; Quality Assurance, Health Care; Quantum Dots; Radiometry; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Intensity-Modulated; Rats, Sprague-Dawley; Receptors, CCR2; Receptors, Transferrin; Regeneration; Registries; Renal Insufficiency, Chronic; Reproducibility of Results; Research Design; Restless Legs Syndrome; Retina; Retinoid X Receptor alpha; Retrospective Studies; Rhenium; Risk Factors; RNA, Messenger; Severity of Illness Index; Sex Factors; Sodium; Sodium Fluoride; Solvents; Spectrometry, Fluorescence; Spectroscopy, Fourier Transform Infrared; Stereoisomerism; Stroke; Structure-Activity Relationship; Tachycardia, Ventricular; Tetracycline; Tetrahydrofolate Dehydrogenase; Tetrahydronaphthalenes; Thermodynamics; Thiophenes; Time Factors; Tinidazole; Tomography, Optical Coherence; Tomography, X-Ray Computed; Topiramate; Toxoplasma; Toxoplasmosis, Cerebral; Transferrin; Treatment Outcome; Up-Regulation; Upper Extremity; Uremia; Uveitis; Vascular Remodeling; Ventricular Fibrillation; Ventricular Function, Left; Ventricular Function, Right; Ventricular Remodeling; Verapamil; Veterans; Visual Acuity; Vitrectomy; Water Pollutants, Chemical; Zea mays; Zirconium

Drug-induced liver injury (DILI) is a major concern in clinical studies as well as in postmarketing surveillance. It is necessary to establish an animal model of DILI for thorough investigation of mechanisms of DILI and searching for protective medications. This article reviews the current status and future perspective on establishment of DILI models based on different hepatotoxic drugs, as well as the underlying mechanisms of liver function damage induced by specific medicine. Therefore, information from this article can help researchers make a suitable selection of animal models for further study.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Drug-Related Side Effects and Adverse Reactions; Humans; Immunosuppression Therapy; Liver; Tetracycline

Drug-induced steatohepatitis is a rare form of liver injury known to be caused by only a handful of compounds. These compounds stimulate the development of steatohepatitis through their toxicity to hepatocyte mitochondria; inhibition of beta-oxidation, mitochondrial respiration, and/or oxidative phosphorylation. Other mechanisms discussed include the disruption of phospholipid metabolism in lysosomes, prevention of lipid egress from hepatocytes, targeting mitochondrial DNA and topoisomerase, decreasing intestinal barrier function, activation of the adenosine pathway, increasing fatty acid synthesis, and sequestration of coenzyme A. It has been found that the majority of compounds that induce steatohepatitis have cationic amphiphilic structures; a lipophilic ring structure with a side chain containing a cationic secondary or tertiary amine. Within the last decade, the ability of many chemotherapeutics to cause steatohepatitis has become more evident coining the term chemotherapy-associated steatohepatitis (CASH). The mechanisms behind drug-induced steatohepatitis are discussed with a focus on cationic amphiphilic drugs and chemotherapeutic agents.

Topics: Amiodarone; Animals; Camptothecin; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Fatty Liver; Hepatocytes; Humans; Irinotecan; Lipid Metabolism; Liver; Methotrexate; Mitochondria, Liver; Organoplatinum Compounds; Oxaliplatin; Perhexiline; Tamoxifen; Tetracycline; Valproic Acid

Genetically engineered mouse models (GEMMs) have proven essential to the study of mammalian gene function in both development and disease. However, traditional constitutive transgenic mouse model systems are limited by the temporal and spatial characteristics of the experimental promoter used to drive transgene expression. To address this limitation, considerable effort has been dedicated to developing conditional and inducible mouse model systems. Although a number of approaches to generating inducible GEMMs have been pursued, several have been restricted by toxic or undesired physiological side effects of the compounds used to activate gene expression. The development of tetracycline (tet)-dependent regulatory systems has allowed for circumvention of these issues resulting in the widespread adoption of these systems as an invaluable tool for modeling the complex nature of cancer progression.

Topics: Animals; Disease Models, Animal; Gene Expression Regulation; Humans; Mice; Neoplasms; Operator Regions, Genetic; Tetracycline; Trans-Activators; Transgenes

The purpose of this review is to give a comprehensive overview of transgenic mouse lines suitable for studying gene function and cellular lineage relationships in lung development, homeostasis, injury, and repair. Many of the mouse strains reviewed in this Perspective have been widely shared within the lung research community, and new strains are continuously being developed. There are many transgenic lines that target subsets of lung cells, but it remains a challenge for investigators to select the correct transgenic modules for their experiment. This review covers the tetracycline- and tamoxifen-inducible systems and focuses on conditional lines that target the epithelial cells. We point out the limitations of each strain so investigators can choose the system that will work best for their scientific question. Current mesenchymal and endothelial lines are limited by the fact that they are not lung specific. These lines are summarized in a brief overview. In addition, useful transgenic reporter mice for studying lineage relationships, promoter activity, and signaling pathways will complete our lung-specific conditional transgenic mouse shopping list.

Topics: Animals; Cell Lineage; Connective Tissue Cells; Disease Models, Animal; Doxorubicin; Epithelial Cells; Gene Expression Regulation; Genes, Reporter; Integrases; Lung; Lung Diseases; Mice; Mice, Transgenic; Species Specificity; Tamoxifen; Tetracycline

Schizophrenia is a devastating disorder. Despite the advance in research techniques in the last couple of decades, the pathogenesis of the disorder still remains poorly understood. Given the lack of pathognomonic feature of the disease and difficulty to analyze molecular pathways in patients, animal models have been instrumental in advancing our understanding of the disease. Recent progress in genetics has identified candidate susceptibility genes for schizophrenia, and generation of new genetic animal models has begun to provide valuable insights into the disease development. However, the complex neurodevelopmental and heterogeneous nature of schizophrenia still poses tremendous challenges for creating credible mouse models. In this review, we will discuss how current genetic systems of temporal and conditional regulation of gene expression have shed lights on the functions of the candidate genes in mouse models of schizophrenia. We also consider the strength and weaknesses of each model. We will argue that further development of more sophisticated genetic animal models is crucial for clarifying the unknowns of schizophrenia.

Topics: Animals; Disease Models, Animal; Estrogen Receptor alpha; Gene Expression Regulation; Gene Transfer Techniques; GTP-Binding Proteins; Humans; Mice; Mice, Transgenic; Nerve Tissue Proteins; Receptors, Dopamine D2; Schizophrenia; Tetracycline

Conditional systems have proven to be efficient and powerful to delineate several aspects of cardiac pathophysiology and diseases. The possibility of addressing a particular time point in animal life is certainly an important breakthrough allowed by conditional strategies with temporal control of either transgene expression or gene modifications. The purpose of this review is to present various mouse models for cardiovascular diseases based on conditional approaches.

Topics: Animals; Cardiovascular Diseases; Disease Models, Animal; Homeostasis; Recombinases; Tetracycline; Trans-Activators

Topics: Alleles; Anti-Bacterial Agents; Antineoplastic Agents; Base Sequence; Disease Models, Animal; Gene Transfer Techniques; Genetic Techniques; Hormone Antagonists; Integrases; Interferons; Mifepristone; Models, Genetic; Promoter Regions, Genetic; Tamoxifen; Tetracycline; Time Factors; Viral Proteins

Autoimmunity is thought to emerge as a consequence of genetic predispositions and environmental tiggering factors. Often the etiology and the mechanisms involved in the autoaggressive destruction of self-components are rather complex and in many cases poorly understood. Chemokines and cytokines are central mediators of inflammatory processes that are involved in initiation and progression of autoimmunity. Many animal models for human autoimmune diseases use transgenic technology to express chemokines and/or cytokines in an organ or tissue specific manner. However, most of these model systems express the transgene irreversibly without considering the time of expression as a very important parameter. Here, we review experiences that were made from using a tetracycline-inducible promotor system (tTA-system) to express TNFalpha at various times during an ongoing autoimmune process, such as the destruction of pancreatic beta-cells in a mouse model for human type 1 diabetes.

Topics: Animals; Autoimmunity; Diabetes Mellitus, Type 1; Disease Models, Animal; Lymphocytic choriomeningitis virus; Mice; Mice, Transgenic; Promoter Regions, Genetic; Tetracycline; Tumor Necrosis Factor-alpha; Virus Diseases

Modelling human disease in the mouse has become an essential activity in biomedical research in order to unravel molecular mechanisms underlying pathological conditions as well as to determine in vivo the consequences of aberrant gene function. The mouse is by far the most accessible mammalian system physiologically similar to humans. Furthermore, the development of novel techniques for manipulating the murine genome, which allow the in vivo modification of virtually any genomic region in a time and/or tissue specific manner, renders the mouse an ideal model system to study human pathological conditions. Modelling human diseases in mice has reached an even greater relevance in the field of haematological malignancies, due to the already advanced characterization of the molecular basis of many haematological disorders. In this review, we describe the most important technological developments that made it possible to reproduce in the mouse the genetic lesions that characterize human haematological malignancies, thus often generating faithful mouse models of the human condition. We provide specific examples of the advantages and limitations of the various genetic approaches utilized to model leukaemia and lymphoma in the mouse. Finally, we discuss the power of mouse modelling in developing and testing novel therapeutic modalities in pre-clinical studies.

Topics: Animals; Disease Models, Animal; Fusion Proteins, bcr-abl; Hematologic Neoplasms; Humans; Leukemia; Leukemia, Promyelocytic, Acute; Lymphoma; Mice; Mice, Transgenic; Models, Biological; Tetracycline

Genetic manipulation techniques are widely used in mice to study the functions of genes. The most common strategy for assessing in vivo function involves making irreversible changes in the genome by homologous recombination. To complement this approach, a number of systems have been developed that allow specific and controlled expression of a gene. One of the more versatile and promising systems is based on the tetracycline (tet) responsive bacterial tetracycline repressor (TetR). In recent years, the tet system has proven to be a valuable method for understanding the function of genes involved in a number of physiological processes, including mouse models for human diseases such as cancer and neurological and pigment disorders. This review will highlight the power and elegance of the tet system by focusing on its utility in the study of two pigment cell-related biological problems, the pathogenesis of melanomas and melanocyte development in the embryo.

Topics: Animals; Disease Models, Animal; Gene Expression Regulation; Humans; Melanoma; Mice; Pigmentation; Tetracycline

Transgenic mouse and gene knockout technologies offer powerful tools for dissecting the roles of specific genes in the process of aging. Tke interpretation of the results of such studies is limited, however, by the fact that the gene of interest of over- or underexpressed throughout the life span of the animal model. Among other problems, this situation makes it difficult to separate the effects that a specific gene has an embryological development from those that it may exert on the subsequent maturation and aging of the animal. It is also not possible with these methods alone to alter the expression of genes in an age-dependent fashion and to assess the effects of these alterations on the aging process. This capacity would be of particular interest in studying genes which are thought to have a role in regulating physiological homeostasis. Because they offer the opportunity to activate or render inactive the expression of genes at will, exogenously regulatable promoter systems, particularly when used in combination with traditional transgenic or gene knockout approaches, provide a new and potentially very powerful tool for studying the effect of selected genes on aging. This review discusses the merits and limitations of the application of either the tetracycline-regulatable promoter system, the RU 486-inducible promoter system, or the ecdysone-inducible promoter system to exogenously regulate the expression of a transcriptionally linked gene and to thus assess the effect of that gene on aging.

Topics: Aging; Animals; Disease Models, Animal; Ecdysone; Embryonic and Fetal Development; Gene Expression Regulation; Growth; Homeostasis; Mice; Mice, Knockout; Mice, Transgenic; Mifepristone; Promoter Regions, Genetic; Tetracycline; Transcription, Genetic; Transcriptional Activation

Anatomic pathology has produced considerable knowledge about environmental teratogens and carcinogens. A special disease registry established by a pathologist provided details of the association between oral contraceptives and hepatic neoplams. Pathologists were also involved in establishing in the link between diethylstilbestrol use and clear-cell adenocarcinomas of the vagina. An area of particular interest has been gender and ethnic differences in the incidence of certain diseases. Pathologists further make use of animal studies to investigate the pathogenesis of human tumors. Finally, stored serum or tissue is often used by pathologists to help diagnose diseases retrospectively. Human skin fibroblasts grown in culture and stored have been especially valuable for laboratory research. This chapter briefly highlights some of the milestones in the detection of enviromental effects through anatomic pathology.

Topics: Adenocarcinoma; Animals; Ataxia Telangiectasia; Contraceptives, Oral; Diethylstilbestrol; Disease Models, Animal; Environment; Ethnicity; Female; Geography; Herpesvirus 4, Human; Humans; Liver Neoplasms; Lymphoproliferative Disorders; Osteosarcoma; Pathology, Clinical; Radiation, Ionizing; Sex Factors; Tetracycline; Thorium Dioxide; Tooth Discoloration; Vaginal Neoplasms; X Chromosome

In young growing rats, fed the lathyrogenic agent aminoacetonitrile for 3 weeks, characteristic skeletal changes developed resembling the chronic state of osteolathyrism. In both lathyritic and untreated control rats, the femoral head, the distal end of the femur, the proximal tibial end, the thalocalcanean joint and the first lumbar vertebra were investigated using undecalcified thin sections and ground sections. The following methods were employed: quantitative morphometrical analysis of bone structure and bone remodelling of the lumbar vertebra, histochemical demonstration of the composition of polysaccharides, detection of the course of collagenous fibres in cartilage and bone by the polarizing microscope, tetracycline-labelling and fluorescence microscopical determination of epiphyseal longitudinal growth and bone formation activity, photometrical quantification of microradiographies and computer-aided determination of the mineral content of bone.

Topics: Aminoacetonitrile; Animals; Bone Diseases; Bone Resorption; Calcinosis; Disease Models, Animal; Exostoses, Multiple Hereditary; Femur Head; Male; Osteoblasts; Osteoclasts; Rats; Spine; Tetracycline; Tibia

The trachoma and LGV organisms, the human pathogens of the species C. trachomatis, cause oculogenital infections and disease syndromes of the eye and genital tract. The incidence of the most prominent disease, endemic trachoma with eye-to-eye transmission, is decreasing all over the world. At the same time there is increasing recognition of high-frequency venereal infections with trachoma organisms and of the genital disease and occasional ocular disease that they cause. Laboratory techniques for diagnosis and investigation are improving, but work with these interesting intermediate agents remains more difficult than that with many other microorganisms. Proper recognition of the diseases is important because specific therapy is available.

Topics: Adolescent; Adult; Animals; Antigens, Bacterial; Child; Child, Preschool; Chlamydia; Chlamydia Infections; Disease Models, Animal; Female; Genital Diseases, Female; Genital Diseases, Male; Humans; Infant; Infant, Newborn; Lymphogranuloma Venereum; Male; Middle Aged; Sulfonamides; Tetracycline; Trachoma; United States

Topics: Acute Disease; Ampicillin; Animals; Anti-Bacterial Agents; Chloramphenicol; Chronic Disease; Corynebacterium; Disease Models, Animal; Dogs; Escherichia coli Infections; Gentamicins; Haplorhini; Kidney; Ligation; Mice; Nalidixic Acid; Nitrofurantoin; Penicillin G; Proteus Infections; Pseudomonas Infections; Pyelonephritis; Rabbits; Rats; Staphylococcal Infections; Streptococcal Infections; Streptomycin; Sulfonamides; Tetracycline; Ureter

Topics: Animals; Anti-Bacterial Agents; Bacitracin; Bird Diseases; Birds; Chlamydia; Chlamydia Infections; Chloramphenicol; Conjunctivitis, Inclusion; Cycloserine; Disease Models, Animal; Erythromycin; Glycosides; Humans; Lymphogranuloma Venereum; Nystatin; Penicillins; Polymyxins; Psittacosis; Sulfonamides; Tetracycline; Trachoma; Vancomycin

Topics: Animals; Anti-Bacterial Agents; Anti-Infective Agents; Chlamydia Infections; Conjunctivitis, Inclusion; Disease Models, Animal; Humans; Penicillins; Psittacosis; Sulfonamides; Tetracycline; Trachoma

Inhalation of dust containing silica particles is associated with severe pulmonary inflammation and lung injury leading to chronic silicosis including fibrotic remodeling of the lung. Silicosis represents a major global health problem causing more than 45.000 deaths per year. The inflammasome-caspase-1 pathway contributes to the development of silica-induced inflammation and fibrosis via IL-1β and IL-18 production. Recent studies indicate that tetracycline can be used to treat inflammatory diseases mediated by IL-1β and IL-18. Therefore, we hypothesized that tetracycline reduces silica-induced lung injury and lung fibrosis resulting from chronic silicosis via limiting IL-1β and IL-18 driven inflammation.. To investigate whether tetracycline is a therapeutic option to block inflammasome-caspase-1 driven inflammation in silicosis, we incubated macrophages with silica alone or combined with tetracycline. The in vivo effect of tetracycline was determined after intratracheal administration of silica into the mouse lung.. Tetracycline selectively blocks IL-1β production and pyroptotic cell death via inhibition of caspase-1 in macrophages exposed to silica particles. Consistent, treatment of silica-instilled mice with tetracycline significantly reduced pulmonary caspase-1 activation as well as IL-1β and IL-18 production, thereby ameliorating pulmonary inflammation and lung injury. Furthermore, prolonged tetracycline administration in a model of chronic silicosis reduced lung damage and fibrotic remodeling.. These findings suggest that tetracycline inhibits caspase-1-dependent production of IL-1β in response to silica in vitro and in vivo. The results were consistent with tetracycline reducing silica-induced pulmonary inflammation and chronic silicosis in terms of lung injury and fibrosis. Thus, tetracycline could be effective in the treatment of patients with silicosis as well as other diseases involving silicotic inflammation.

Topics: Animals; Caspase 1; Caspase Inhibitors; Disease Models, Animal; Male; Mice; Mice, Inbred C57BL; Pneumonia; Protein Synthesis Inhibitors; Pulmonary Fibrosis; Silicon Dioxide; Tetracycline

Topics: Animals; Bandages; Cell Line; Ciprofloxacin; Disease Models, Animal; Drug Compounding; Drug Synergism; Escherichia coli; Fibroblasts; Gelatin; Humans; Microbial Viability; Nanofibers; Polyesters; Skin; Staphylococcus aureus; Tetracycline; Wound Healing

Tetracycline is used as a fluorescent reagent to measure bone formation activity in bone histomorphometric analyses. However, there is a possibility to lead a different conclusion when it is used in a bacteria-infected murine model since the tetracycline is considered to work as an antibiotic reagent. There are non-antibiotic fluorescent reagents such as alizarin and calcein for measuring bone formation activity. The purpose of this study was to clarify whether tetracycline could be an appropriate reagent to measure bone formation activity in a murine bacterial model in the same way as a non-antibiotic fluorescent reagent. We used

Topics: Animals; Anti-Bacterial Agents; Disease Models, Animal; Indicators and Reagents; Mice; Osteogenesis; Streptococcus mutans; Tetracycline

Several classes of antibiotics have long been known to have beneficial effects that cannot be explained strictly on the basis of their capacity to control the infectious agent. Here, we report that tetracycline antibiotics, which target the mitoribosome, protected against sepsis without affecting the pathogen load. Mechanistically, we found that mitochondrial inhibition of protein synthesis perturbed the electron transport chain (ETC) decreasing tissue damage in the lung and increasing fatty acid oxidation and glucocorticoid sensitivity in the liver. Using a liver-specific partial and acute deletion of Crif1, a critical mitoribosomal component for protein synthesis, we found that mice were protected against sepsis, an observation that was phenocopied by the transient inhibition of complex I of the ETC by phenformin. Together, we demonstrate that mitoribosome-targeting antibiotics are beneficial beyond their antibacterial activity and that mitochondrial protein synthesis inhibition leading to ETC perturbation is a mechanism for the induction of disease tolerance.

Topics: Animals; Anti-Bacterial Agents; Cell Cycle Proteins; Disease Models, Animal; Doxycycline; Electron Transport; Hep G2 Cells; Humans; Lipid Metabolism; Liver; Lung; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitochondria; Sepsis; Tetracycline

The tetracycline regulatory system provides a tractable strategy to interrogate the role of oncogenes in the initiation, maintenance, and regression of tumors through both spatial and temporal control of expression. This approach has several potential advantages over conventional methods to generate genetically engineered mouse models. First, continuous constitutive overexpression of an oncogene can be lethal to the host impeding further study. Second, constitutive overexpression fails to model adult onset of disease. Third, constitutive deletion does not permit, whereas conditional overexpression of an oncogene enables the study of the consequences of restoring expression of an oncogene back to endogenous levels. Fourth, the conditional activation of oncogenes enables examination of specific and/or developmental state-specific consequences.Hence, by allowing precise control of when and where a gene is expressed, the tetracycline regulatory system provides an ideal approach for the study of putative oncogenes in the initiation as well as the maintenance of tumorigenesis and the examination of the mechanisms of oncogene addiction. In this protocol, we describe the methods involved in the development of a conditional mouse model of MYC-induced T-cell acute lymphoblastic leukemia.

Topics: Animals; Animals, Genetically Modified; Apoptosis; Carcinogenesis; Cell Line, Tumor; Cell Transformation, Neoplastic; Disease Models, Animal; DNA; Gene Expression Regulation; Genes, myc; Genetic Engineering; Humans; Mice; Oncogenes; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma; Protein Synthesis Inhibitors; Proto-Oncogene Proteins c-myc; T-Lymphocytes; Tetracycline

When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen ∼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.

Topics: Animals; Antiviral Agents; Artificial Intelligence; Chlorocebus aethiops; Disease Models, Animal; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Immunocompetence; Inhibitory Concentration 50; Methacycline; Mice, Inbred C57BL; Protease Inhibitors; Quantitative Structure-Activity Relationship; Small Molecule Libraries; Vero Cells; Zika Virus; Zika Virus Infection

There is currently no effective treatment for neurological impairment caused by traumatic brain injury (TBI). It has been reported that excessive iron production in the brain may be a key factor in neurological impairment. In the present study, we investigated the effects of minocycline, a semi-synthetic tetracycline antibiotic, against TBI-induced neurological impairment and explored its underlying mechanism. Neurological impairment was assessed by foot-fault test, cylinder test, wire hang test, and Morris water maze. Nissl staining was performed to evaluate cell viability in the brain. The iron concentrations in cerebrospinal fluid (CSF), serum, and brain tissues were examined. The Fe

Topics: Animals; Anti-Bacterial Agents; Brain; Brain Injuries, Traumatic; Cation Transport Proteins; Cerebral Cortex; Chelating Agents; Disease Models, Animal; Ferritins; Hippocampus; Iron; Male; Maze Learning; Minocycline; Nervous System Diseases; Rats; Rats, Sprague-Dawley; Receptors, Transferrin; Tetracycline

Recent emergence of high-level tigecycline resistance mediated by Tet(X3/X4) in Enterobacteriaceae undoubtably constitutes a serious threat for public health worldwide. Antibiotic adjuvant strategy makes antibiotic more effective against these resistant pathogens through interfering intrinsic resistance mechanisms or enhancing antibiotic actions. Herein, we screened a collection of drugs to identify compounds that are able to restore tigecycline activity against resistant pathogens. Encouragingly, we discovered that anti-HIV agent azidothymidine dramatically potentiates tigecycline activity against clinically resistant bacteria. Meanwhile, addition of azidothymidine prevents the evolution of tigecycline resistance in E. coli and the naturally occurring horizontal transfer of tet(X4). Evidence demonstrated that azidothymidine specifically inhibits DNA synthesis and suppresses resistance enzyme activity. Moreover, in in vivo infection models by Tet(X4)-expression E. coli, the combination of azidothymidine and tigecycline achieved remarkable treatment benefits including increased survival and decreased bacterial burden. These findings provide an effective regimen to treat infections caused by tigecycline-resistant Escherichia coli.

Topics: Animals; Anti-Bacterial Agents; Anti-HIV Agents; Disease Models, Animal; Drug Synergism; Escherichia coli; Escherichia coli Infections; Escherichia coli Proteins; Female; Gene Expression Regulation, Bacterial; Mice; Microbial Sensitivity Tests; Microbial Viability; Peritonitis; Tetracycline; Tetracycline Resistance; Zidovudine

Although antibiotic-induced hepatotoxicity is recoverable with mild impairment, and some cases were reported to cause morbidity. However, an adjuvant is essential in reducing such incidences.. The aim of this study is to evaluate the protective effect of ascorbic acid on antibiotic induced liver toxicity using liver slices.. Fresh liver slices were incubated with different concentrations of sulfamethoxazole tetracycline and clavulanic acid along with ascorbic acid (200μg/ml) for 2 hours. The liver homogenate was assessed for markers like ALT, AST, MDA and CAT levels. Cytotoxicity assessment was performed using MTT assay.. Incubating liver slices with all three antibiotics shows elevated levels of aminotransferases, MDA and CAT enzyme when compared to the control groups which indicates the level of hepatotoxicity. In the presence of ascorbic acid, the elevated levels of TBARS, ALT and AST were significantly reduced which showcases the protective effect of ascorbic acid. The percentage survival of cell was also shown to have improved while accessed using cell viability assay.. Obtained data suggests that consuming vitamin C or vitamin C containing food like citrus fruits or green leafy vegetables equivalent to 3g/day during antibiotic treatment, perhaps put down the risk of liver toxicity to a greater extent.

Topics: Animals; Anti-Bacterial Agents; Antioxidants; Ascorbic Acid; Cell Survival; Chemical and Drug Induced Liver Injury; Chickens; Clavulanic Acid; Disease Models, Animal; Drug Evaluation, Preclinical; Hepatocytes; Humans; Lipid Peroxidation; Liver; Mice; Oxidative Stress; Primary Cell Culture; Sulfamethoxazole; Tetracycline

Recent evidence suggests that antibiotic-induced changes in the composition of intestinal microflora, as well as the systemic immunoendocrine effects that result from them, can modulate myocardial tolerance to ischemia-reperfusion injury. The aim of this study was to investigate the effects of tetracycline (TTC) on myocardial infarct size in the isolated hearts obtained from obese rats with chemically-induced colitis (CIC). The association between TTC-induced changes in infarct size and intestinal microbiome composition as well as plasma levels of cytokines and short-chain fatty acids (SCFAs) was also studied.. Obesity was induced in Wistar rats by feeding them a high-fat, high-carbohydrate diet for five weeks. A single rectal administration of 3% acetic acid (2 mL) to the rats resulted in CIC. Healthy rats as well as obese rats with CIC received TTC (15 mg daily for 3 days) via gavage. The rats were euthanized, after which isolated heart perfusion with simulated global ischemia and reperfusion was performed. Infarct size was determined histochemically. Lipopolysaccharide (LPS) and cytokine levels in plasma were measured by enzyme-linked immunosorbent assay, whereas SCFA levels in plasma were measured by gas chromatography/mass spectrometry. The intestinal microbiome was analyzed using reverse transcription polymerase chain reaction.. The treatment with TTC resulted in significant infarct size limitation (50 ± 7 vs. 62 ± 4% for the control mice, p < 0.05) in the hearts from intact animals. However, infarct size was not different between the control rats and the obese rats with CIC. Furthermore, infarct size was significantly larger in TTC-treated obese rats with CIC than it was in the control animals (77 ± 5%, p < 0.05). The concentrations of proinflammatory cytokines and LPS in serum were elevated in the obese rats with CIC. Compared to the control rats, the rats with both obesity and CIC had lower counts of Lactobacillus and Bifidobacterium spp. but higher counts of Escherichia coli. The effects of TTC on infarct size were not associated with specific changes in SCFA levels.. TTC reduced infarct size in the healthy rats. However, this effect was reversed in the obese animals with CIC. Additionally, it was associated with specific changes in gut microbiota and significantly elevated levels of cytokines and LPS.

Topics: Animals; Biomarkers; Body Weight; Colitis; Disease Models, Animal; Fatty Acids, Volatile; Gastrointestinal Microbiome; Heart Function Tests; Male; Myocardial Infarction; Obesity; Rats; Tetracycline

A series of novel fluorine-containing lupane triterpenoid acid derivatives with fluoroaromatic amide moieties at the C-28 position (1-8) or with 2-(fluoroacyl)cyclopentane-1,3-dione fragments at the C-3 position (9-18) of lupane skeleton was synthesized. A simple synthesis of novel lupane triterpenoid hybrids with 2-(fluoroacyl)-2-cyclopenten-1-one moieties was developed. An interaction of 2-acyl-3-chlorocyclopent-2-en-1-ones, obtained from corresponding cyclic β-triketones, with methyl 3-amino-3-deoxybetulinate gave 3β-isomers (9-13) and 3α-isomers (14-18) of target hybrids, which were isolated as individual compounds. Anti-inflammatory properties of selected synthesized compounds were studied in vivo using the histamine-, concanavalin A- and sheep erythrocytes immunization-induced mouse paw edema models. The antioxidant activity was investigated in vivo on the model of tetracycline-induced hepatitis. Majority of synthesized fluorine-containing lupane triterpenoid acid derivatives exhibited significant anti-inflammatory and antioxidant effects. Among studied compounds, 3β-hybrid 11 with 2-perfluorobutanoyl-2-cyclopenten-1-one moiety was the most potent bioactive compound.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Betulinic Acid; Concanavalin A; Disease Models, Animal; Drug Design; Edema; Female; Fluorine; Hepatitis; Histamine; Male; Mice; Mice, Inbred C57BL; Molecular Conformation; Pentacyclic Triterpenes; Tetracycline; Triterpenes

During the hatching process, chicks are exposed to opportunistic and/or pathogenic organisms, such as virulent or avirulent Escherichia coli. Virulent E. coli strains have not been feasible for induction of neonatal colibacillosis via in ovo challenge due to high embryonic mortality. In this manuscript, we describe the addition and co-administration of the bacteriostatic antibiotic tetracycline to a virulent E. coli challenge culture, improving hatchability and livability of seeder chicks while allowing robust horizontal transmission in the hatching cabinet to contact chicks. Experiment 1 consisted of 3 trials. Experiment 1, trial 1 was conducted to determine an effective ratio of E. coli challenge and tetracycline dose to be utilized in the seeder model. Trials 2 and 3 were conducted to evaluate the transmission of E. coli from seeder to contact chicks. Experiment 2 consisted of 3 independent 7-D trials where body weight gain (BWG), mortality, and selected enteric bacterial recovery were evaluated. In trials 1 to 3, significantly (P < 0.05) more Gram-negative bacteria were recovered from whole gut samples (GIT) vs. negative controls on day of hatch, from both seeder and contact chicks. At day 7 in trial 1, contact chicks had significantly (P < 0.05) more Gram-negative bacteria recovered from the GIT than the negative control, but not in trials 2 and 3. Presumptive lactic acid bacterial recovery was elevated in contact and seeder chicks compared to the negative control in all 3 trials. Contact challenge caused a significant (P < 0.05) reduction in BWG in 2 out of 3 trials at day 7, and there was a significant (P < 0.05) increase in mortality as compared to the negative controls in all trials. These data suggest that co-administration of a virulent E. coli strain with tetracycline allows for hatch of direct challenged chicks and effective horizontal transmission to contact chicks during the hatching process, as evidenced by reduced day 7 performance and altered selected enteric bacterial recovery.

Topics: Animals; Anti-Bacterial Agents; Chickens; Disease Models, Animal; Escherichia coli; Escherichia coli Infections; Ovum; Poultry Diseases; Tetracycline; Virulence

Treatment of azole-resistant Candida albicans infections continues to pose significant challenges. With limited options of licensed agents, drug combinations may be a practical treatment alternative. In our previous studies, the combinations minocycline/fluconazole (MINO/FLC) and doxycycline/fluconazole (DOXY/FLC) shown synergistic effects in vitro. It is necessary to explore their appropriate dosage, potential toxicity and in vivo efficacy.. The Galleria mellonella infection model was employed to study the in vivo efficacy of MINO/FLC and DOXY/FLC by survival analysis, quantification of C. albicans fungal burden and histological studies.. The survival rates of G. mellonella larvae infected with lethal doses of resistant C. albicans CA10 increased significantly when treated with the drug combinations compared with FLC treatment alone, and the fungal burden was reduced by almost four-fold. The histopathological study showed that fewer infected areas in larvae were observed and the destructive degree was less when larvae were exposed to the drug combinations.. These findings suggest that combination of a tetracycline antibiotic (MINO or DOXY) with FLC has antifungal activity against azole-resistant C. albicans in vivo. This is in agreement with several previous in vitro studies and provides preliminary in vivo evidence that such a combination might be useful therapeutically.

Topics: Animals; Antifungal Agents; Candida albicans; Candidiasis; Colony Count, Microbial; Disease Models, Animal; Drug Resistance, Fungal; Drug Therapy, Combination; Fluconazole; Histocytochemistry; Lepidoptera; Survival Analysis; Tetracycline; Treatment Outcome

Staphylococcus aureus native efflux pump Tet38 confers resistance to tetracycline when overexpressed. tet38 expression is selectively upregulated in infection sites. This study evaluated the effect of Tet38 on tetracycline response in a murine subcutaneous abscess model.. S. aureus MW2 and its tet38 mutant were injected subcutaneously on the opposite flanks of each mouse. The infected mice were treated with tetracycline (10 mg/kg) or PBS (control) intraperitoneally every 12 h. The efficacy of tetracycline against S. aureus was measured by the relative change in viable bacteria in the abscesses 24 h after infection compared with the initial inoculum. Plasmid-based tet38-complemented strains were created and used to infect the mice followed by tetracycline or PBS treatment.. The increased bacterial loads of S. aureus MW2 and its tet38 mutant in the abscess after 24 h were similar. Tetracycline produced significant decreases of both MW2 and the tet38 mutant compared with control. Although the tetracycline MICs for MW2 and the tet38 mutant did not differ in vitro, the antibacterial effect of tetracycline was significantly 2-fold greater in the tet38 mutant compared with the MW2 parental strain in vivo with a decrease of 0.67 ± 0.21 and 0.35 ± 0.19 log10 cfu/abscess, respectively (P < 0.05). The increased tetracycline activity in the tet38 mutant was complemented by plasmid-encoded tet38.. This study demonstrated that selective increased expression of tet38 in an abscess can affect tetracycline efficacy against S. aureus in vivo, highlighting an effect of native efflux pumps on response to therapy not reflected by testing in vitro.

Topics: Abscess; Animals; Anti-Bacterial Agents; Bacterial Load; Bacterial Proteins; Disease Models, Animal; Drug Resistance, Multiple, Bacterial; Male; Membrane Transport Proteins; Mice; Microbial Sensitivity Tests; Skin; Staphylococcal Infections; Staphylococcus aureus; Tetracycline

Normally, Candida albicans is a commensal microbe that resides in the human oral cavity, gut and vagina. However, the fungus can cause mucosal and systemic infections in immunocompromised individuals. The mechanism by which local mucosal infections progress to systemic candidiasis is poorly understood. Here, a murine model of gastrointestinal (GI) candidiasis was developed by inoculation of the oral cavity, followed by treatment with tetracycline (TC) and prednisolone (PSL). Temporal progression from a local infection of the oral cavity to a systemic infection was then monitored. Histological analysis of tissues from mice treated with both TC and PSL revealed massive infiltration of the tongue and stomach by hyphae. PSL increased the fungal burden in the tongue, stomach and small intestine, and facilitated dissemination to the spleen, kidney and liver within 3 days post-infection. Treatment with both TC and PSL supressed interferon (IFN)-γ and interleukin (IL)-17 (cytokines that play key roles in host defence against fungal infection) levels in the tongue, which were induced by C. albicans infection. In addition, the mucosal layer of the small intestine of mice treated with both TC and PSL was almost destroyed by the fungal infection; this may be a critical event that allows passage of the fungus across the mucosa and into the systemic circulation. Thus, this mouse model is useful for studying mechanisms underlying progression of C. albicans from a local infection of the oral cavity to a systemic infection in immunocompromised individuals.

Topics: Animals; Anti-Bacterial Agents; Candida albicans; Candidiasis; Candidiasis, Oral; Cytokines; Disease Models, Animal; Drug Combinations; Female; Gastrointestinal Diseases; Gastrointestinal Tract; Immunocompromised Host; Interferon-gamma; Interleukin-17; Mice; Mice, Inbred ICR; Mucous Membrane; Prednisolone; Stomach; Tetracycline; Tongue

A number of previous studies have indicated that the genetic variation at the collage type I alpha 1 (COLIA1) gene locus influences susceptibility to osteoporosis. However, seldom have studies reported the effect of gene delivery using an adenovirus vector carrying human recombinant COLIA1 cDNA on stimulating osteogenic activity of osteoblasts and enhancing fracture healing of ovariectomized rats. The current study was performed to demonstrate whether direct gene delivery using an adenovirus vector carrying human recombinant COLIA1 cDNA could stimulate osteogenic activity of osteoblast in vitro and enhance fracture healing of ovariectomized rats in vivo. In vitro, the tet-on system regulated COLIA1 gene adenovirus was constructed and transfected to osteoblasts. COLIA1 mRNA and collagen type I levels were assessed by reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay to determine whether adenovirus transfected successfully. Osteogenic activity of the osteoblasts was assessed by alkaline phosphatase activity, immunohistochemical staining, immunofluorescent staining, mineralized matrix formation, and extracellular calcium levels. In vivo, adenovirus-delivered COLIA1 gene was injected into the fracture site of the tibia in an ovariectomized rat model of osteoporosis, and bone callus condition was assessed to determine whether the COLIA1 gene could accelerate osteoporotic fracture healing. In vitro, the results showed that COLIA1 gene adenovirus transfection could increase osteoblast COLIA1 gene expression and collagen type I protein synthesis, increase alkaline phosphatase activity, and stimulate calcium nodules formation, which exhibited a direct osteogenic effect on the osteoblasts. In vivo, local injection of COLIA1 gene adenovirus increased collagen type I expression, restored bone mineral density, and accelerated fracture healing in ovariectomized rats, without increasing serum collagen type I and liver COLIA1 mRNA levels. This study suggests direct gene delivery using an adenovirus carrying human COLIA1 cDNA can stimulate the osteogenic activity of osteoblasts in vitro and enhance bone fracture healing in vivo. The tet-on system is an ideal gene regulatory system for effective and safe regulation of the therapeutic gene.

Topics: Adenoviridae; Animals; Bone Density; Cell Differentiation; Collagen Type I; Collagen Type I, alpha 1 Chain; Disease Models, Animal; Genetic Therapy; Humans; Osteoblasts; Osteoporosis; Osteoporotic Fractures; Rats; Recombinant Proteins; Tetracycline; Transfection

OBJECTIVE To compare the efficacy of various concentrations and combinations of serum, EDTA, 3 tetracyclines, and N-acetylcysteine (NAC) for collagenase inhibition in an in vitro corneal degradation model. SAMPLE Grossly normal corneas from recently euthanized dogs and horses and fresh serum from healthy dogs and horses. PROCEDURES Serum was pooled by species for in vitro use. For each species, sections of cornea were dried, weighed, and incubated with clostridial collagenase (800 U/mL) in 5 mL of a 5mM calcium chloride-saline (0.9% NaCl) incubation solution and 500 μL of 1 of 19 treatments (homologous serum; 0.3%, 1.0%, or 2% EDTA; 0.1%, 0.5%, or 1.0% tetracycline, doxycycline, or minocycline; 0.5%, 1.0%, or 5.0% NAC; serum with 0.5% tetracycline; serum with 1.0% EDTA; or 1.0% EDTA with 0.5% tetracycline). Positive and negative control specimens were incubated with 5 mL of incubation solution with and without collagenase, respectively. Each control and treatment was replicated 4 times for each species. Following incubation, corneal specimens were dried and reweighed. The percentage corneal degradation was calculated and compared among treatments within each species. RESULTS Treatments with tetracyclines at concentrations ≥ 0.5%, with EDTA at concentrations ≥ 0.3%, and with NAC at concentrations ≥ 0.5% were more effective at preventing corneal degradation than serum in both species. The efficacy of each combination treatment was equal to or less than that of its components. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested EDTA, tetracyclines, and NAC may be beneficial for topical treatment of keratomalacia, but in vivo studies are required.

Topics: Acetylcysteine; Animals; Anti-Bacterial Agents; Collagenases; Cornea; Corneal Diseases; Disease Models, Animal; Dogs; Doxycycline; Edetic Acid; Horses; Matrix Metalloproteinase Inhibitors; Minocycline; Serum; Tetracycline

A dual local drug delivery system (DDS) composed of calcium phosphate bioceramic nanocarriers aimed at treating the antibacterial, anti-inflammatory, and bone-regenerative aspects of periodontitis has been developed. Calcium-deficient hydroxyapatite (CDHA, Ca/P = 1.61) and tricalcium phosphate (β-TCP) were prepared by microwave-accelerated wet chemical synthesis method. The phase purity of the nanocarriers was confirmed by x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR), while the transmission electron microscopy (TEM) confirmed their nanosized morphology. CDHA was selected as carrier for the antibiotic (tetracycline) while TCP was chosen as the anti-inflammatory drug (ibuprofen) carrier. Combined drug release profile was studied in vitro from CDHA/TCP (CTP) system and compared with a HA/TCP (BCP) biphasic system. The tetracycline and ibuprofen release rate was 71 and 23% from CTP system as compared to 63 and 20% from BCP system. CTP system also showed a more controlled drug release profile compared to BCP system. Modeling of drug release kinetics from CTP system indicated that the release follows Higuchi model with a non-typical Fickian diffusion profile. In vitro biological studies showed the CTP system to be biocompatible with significant antibacterial and anti-inflammatory activity. In vivo implantation studies on rat cranial defects showed greater bone healing and new bone formation in the drug-loaded CTP system compared to control (no carrier) at the end of 12 weeks. The in vitro and in vivo results suggest that the combined drug delivery platform can provide a comprehensive management for all bone infections requiring multi-drug therapy.

Topics: 3T3 Cells; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Biocompatible Materials; Bone Regeneration; Calcium Phosphates; Delayed-Action Preparations; Disease Models, Animal; Drug Delivery Systems; Female; Hydroxyapatites; Ibuprofen; Mice; Nanoparticles; Periodontitis; Rats; Tetracycline

This study aimed to investigate the improved therapeutic efficacy and pharmacokinetic profiles of simvastatin (SIM) with imparted bone targeting potential using tetracycline-mediated PEG-PLGA (TC-PEG-PLGA) micelles in osteoporotic rats. The SIM-loaded TC-PEG-PLGA (TC-PEG-PLGA/SIM) micelles were evaluated for particle size, morphology, stability, loading efficiency, cell viability, bone mineral binding ability in vitro, mineralization, pharmacokinetics, and pharmacodynamics. TC-PEG-PLGA conjugates were successfully and could self-assembly form micelles in aqueous medium with a 19.4 μg/mL critical micelle concentration. Then, TC-PEG-PLGA/SIM micelles were prepared with solvent diffusion method, and the obtained micelles (56.21 ± 7.39 nm average size; 81.8 ± 3.1% encapsulation efficiency; and 7.56 ± 0.27% drug loading) led to the prolonged release of SIM from micelles. Cellular uptake test indicated that TC had no effects on micellar internalization and micellar internalization was mainly involved with clathrin-mediated endocytic pathway. In vivo pharmacokinetic results indicated that TC-PEG-PLGA/SIM micelles exhibited a significantly prolonged time in systemic circulation and were preferentially accumulated in bone tissue. TC-PEG-PLGA/SIM micelles showed better therapeutic effects, as reflected by the improved bone mineral density, bone mineral content, and bone mechanical strength. Overall, these results suggested that TC-PEG-PLGA/SIM micelles provide several advantages, including prolonged systemic circulation, enhanced bone tissue distribution, and improved therapeutic outcomes in osteoporotic rats.

Topics: Animals; Bone and Bones; Disease Models, Animal; Drug Carriers; Drug Compounding; Human Umbilical Vein Endothelial Cells; Humans; Micelles; Osteoporosis; Particle Size; Polyesters; Polyethylene Glycols; Rats; Simvastatin; Tetracycline

The Wolrd Health Organization (WHO) encourages all countries to investigate antimalarial drug substances derived from herbal sources with the slogan "Hunt of the Next Artemisinin" due to the emergence of resistant strains of Plasmodium species to artemisinin. In the broad and simple sense, it was planned to help guide the young researchers set in-vitro and in-vivo models of malaria in order to be used in drug research and active ingredient studies.. In-vitro study, young Plasmodium berghei trophozoites were removed from the liquid nitrogen tank and resuspended in appropriate conditions, followed by incubation with chloroquine and tetracycline at concentrations of 0.1, 0.4, 0.8, 1.6, 6.4, 12.8 μg/mL for 24 hours at +37°C in a shaking incubator. In-vivo studies, Tetracycline group (TG) and Chloroquine group (KG) were administered 50 mg/kg of tetracycline and chloroquine by intragastric lavage and untreated control group (TACG) were administered the same amount of saline via the same route. The suppression of parasitemia in mice was followed for 24 days.. In our in-vitro study it was observed that 0.8 μg/mL of chloroquine and 1.6 μg/mL of tetracycline was enough to suppress parasitemia. In our in-vivo drug study, all of the mice in the TG group died at day 24, and all of the mice in the TAKG group died at day 12, with no parasitemia observed in the mice in the KG group.. Our study suggests that if tetracycline therapy is administered when the induction of chloroquine therapy is delayed, the exacerbation of the parasitemia may be prevented and when chloroquine is obtained chloroquine therapy can be commenced thus preventing the loss of the patient.

Topics: Animals; Antimalarials; Artemisinins; Chloroquine; Disease Models, Animal; Drug Evaluation, Preclinical; In Vitro Techniques; Malaria; Male; Mice; Mice, Inbred BALB C; Plant Extracts; Plasmodium berghei; Tetracycline

The aim of the present study was to construct a nonvascular transport disc to repair the canine mandibular defects model and to perform a dynamic analysis of the new bone obtained by nonvascular transport distraction osteogenesis (NTDO) in canines.. Thirty adult dogs were randomly divided into 3 groups, with 10 dogs in each group. Canine mandibular defect models of NTDO were constructed. All the dogs were marked by tetracycline hydrochloride at a different distraction stage. The dogs were euthanized at 2, 4, and 12 weeks after distraction, and the quality ratio of calcium and phosphate for the new bone was measured using electron dispersive spectroscopy.. The canine mandibular defects were successfully repaired. Using tetracycline hydrochloride, we successfully observed the quality and speed of new bone formation. The quality ratio of calcium and phosphate was similar between the new bone formation and the original bone. The time spent using a nonvascular transport disc to repair mandibular defects was consistent with using a vascularized transport disc, and the quality of the new bone and the original bone was exactly the same.. When the bone mass is insufficient or the conditions are not suitable for a vascularized transport disc, the nonvascular transport disc can be used as an alternative.

Topics: Animals; Bone Matrix; Bone Regeneration; Calcium; Disease Models, Animal; Dogs; Fluorescent Dyes; Mandible; Mandibular Diseases; Microscopy, Electron, Scanning; Osteogenesis; Osteogenesis, Distraction; Phosphates; Random Allocation; Spectrometry, X-Ray Emission; Tetracycline; Time Factors

Endoplasmic reticulum (ER) stress is known to be involved in the development of several metabolic disorders, including non-alcoholic fatty liver disease (NAFLD). Tetracycline can cause hepatic steatosis, and ER stress may be involved in tetracycline-induced fatty liver. Our previous study showed that bicyclol has been proven to protect against tetracycline-induced fatty liver in mice, and ER stress may also be involved in bicyclol's hepatoprotective effect. Therefore, this study was performed to investigate the underlying mechanisms associated with ER stress and apoptosis, by which bicyclol attenuated tetracycline-induced fatty liver in mice. Bicyclol (300 mg/kg) was given to mice by gavage 3 times. Tetracycline (200 mg/kg, intraperitoneally) was injected at 1 h after the last dose of bicyclol. At 6 h and 24 h after single dose of tetracycline injection, serum ALT, AST, TG, CHO and hepatic histopathological examinations were performed to evaluate liver injuries. Hepatic steatosis was assessed by the accumulation of hepatic TG and CHO. Moreover, hepatic apoptosis and ER stress related markers were determined by TUNEL, real-time PCR, and western blot. As a result, bicyclol significantly protected against tetracycline-induced fatty liver as evidenced by the decrease of elevated serum transaminases and hepatic triglyceride, and the attenuation of histopathological changes in mice. In addition, bicyclol remarkably alleviated hepatic apoptosis and the gene expression of caspase-3, and increased the gene expression of XIAP. The gene expressions of ER stress-related markers, including CHOP, GRP78, IRE-1α, and ATF6, which were downregulated by bicyclol pretreatment in tetracycline-injected mice. These results suggested that bicyclol protected tetracycline-induced fatty liver partly due to its ability of anti-apoptosis associated with ER stress.

Topics: Alanine Transaminase; Animals; Apoptosis; Aspartate Aminotransferases; Biphenyl Compounds; Cholesterol; Disease Models, Animal; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Gene Expression; Heat-Shock Proteins; Liver; Male; Mice; Mice, Inbred ICR; Non-alcoholic Fatty Liver Disease; Tetracycline; Transcription Factor CHOP; Triglycerides

The purpose of the present study was to study the synergy potential of gallic acid-based derivatives in combination with conventional antibiotics using multidrug resistant cultures of Escherichia coli. Gallic acid-based derivatives significantly reduced the MIC of tetracycline against multidrug resistant clinical isolate of E. coli. The best representative, 3-(3',4,'5'-trimethoxyphenyl)-4,5,6-trimethoxyindanone-1, an indanone derivative of gallic acid, was observed to inhibit ethidium bromide efflux and ATPase which was also supported by in silico docking. This derivative extended the post-antibiotic effect and decreased the mutation prevention concentration of tetracycline. This derivative in combination with TET was able to reduce the concentration of TNFα up to 18-fold in Swiss albino mice. This derivative was nontoxic and well tolerated up to 300 mg/kg dose in subacute oral toxicity study in mice. This is the first report of gallic acid-based indanone derivative as drug resistance reversal agent acting through ATP-dependent efflux pump inhibition.

Topics: Administration, Oral; Animals; Anti-Bacterial Agents; Disease Models, Animal; Drug Synergism; Drug-Related Side Effects and Adverse Reactions; Enzyme Inhibitors; Escherichia coli; Gallic Acid; Indans; Macrophages; Mice; Microbial Sensitivity Tests; Molecular Docking Simulation; Shock, Septic; Tetracycline

This study evaluated the photoinactivation of Candida albicans in a murine model of oral candidiasis using chloro-aluminum phthalocyanine (ClAlP) encapsulated in cationic nanoemulsions (NE) and chloro-aluminum phthalocyanine (ClAlP) diluted in DMSO (DMSO) as photosensitizer (PS). Seventy-five 6-week-old female Swiss mice were immunosuppressed and inoculated with C. albicans to induce oral candidiasis. PDT was performed on the tongue by the application of the photosensitizers and LED light (100 J cm(-2) -660 nm). Twenty-four hours and 7 days after treatments, microbiological evaluation was carried out by recovering C. albicans from the tongue of animals (CFU ml(-1) ). Then, mice were sacrificed and the tongues were surgically removed for histological and biomolecular analysis of pro- and anti-inflammatory cytokines. Data were analyzed by ANOVA followed by Tukey's post hoc test. ClAlP-NE-mediated PDT reduced 2.26 log10 of C. albicans recovered from the tongue when compared with the control group (P-L-) (P < 0.05). PDT did not promote adverse effects on the tongue tissue. Seven days after treatment, all animals were completely healthy. In summary, PDT mediated by chloro-aluminum phthalocyanine entrapped in cationic nanoemulsions was effective in reducing C. albicans recovered from the oral lesions of immunocompromised mice.

Topics: Animals; Candida albicans; Candidiasis, Oral; Cytokines; Disease Models, Animal; Female; Indoles; Mice; Organometallic Compounds; Photochemotherapy; Photosensitizing Agents; Random Allocation; Tetracycline; Tongue

Antibiotics are among the most frequently prescribed drugs in human and animal medicine. With antibiotic resistance being a serious threat to veterinary and public health, the prudent use of antibiotics receives much attention. Less well known is that incorrect use of antimicrobial agents may also lead to increased bacterial virulence with the potential of a more severe clinical course of infection. Therefore, the aim of this study was to investigate the effect of subtherapeutic doses of tetracyclines on htpG virulence gene expression in Salmonella Typhimurium and on the course of salmonellosis.. Salmonella strains containing an htpG-luxCDABE transcriptional fusion were constructed. Phenotype microarrays and tetracycline treatment were used to investigate their htpG expression. A Salmonella transposon mutant bank was used to identify genes involved in the induction of htpG gene expression. Finally, the in vitro results were linked to the in vivo situation using a Salmonella mouse model.. We demonstrate that subtherapeutic antimicrobial concentrations can exacerbate bacterial infections through direct up-regulation of bacterial virulence factors using Salmonella Typhimurium 112910a phage type 120/ad as a model organism. Phenotype microarrays showed that expression of the Salmonella Typhimurium virulence gene htpG is increased by several tetracycline antimicrobials at values below their MIC, a process that requires intact Salmonella LPS genes. Exposure of experimentally infected DBA/2J mice to subtherapeutic doxycycline concentrations resulted in htpG-mediated exacerbation of Salmonella Typhimurium infection.. These findings show that the Salmonella isolate used in this study can respond to subtherapeutic tetracycline pressure by increasing its virulence and disease severity.

Topics: Animals; Anti-Bacterial Agents; Artificial Gene Fusion; Bacterial Proteins; Disease Models, Animal; DNA Transposable Elements; Doxycycline; Female; Genes, Reporter; Genetic Testing; HSP90 Heat-Shock Proteins; Luciferases; Mice, Inbred DBA; Microarray Analysis; Microbial Sensitivity Tests; Mutagenesis, Insertional; Salmonella Infections, Animal; Salmonella typhimurium; Tetracycline; Virulence; Virulence Factors

Combination treatment is increasingly used to fight infections caused by bacteria resistant to two or more antimicrobials. While multiple studies have evaluated treatment strategies to minimize the emergence of resistant strains for single antimicrobial treatment, fewer studies have considered combination treatments. The current study modeled bacterial growth in the intestine of pigs after intramuscular combination treatment (i.e. using two antibiotics simultaneously) and sequential treatments (i.e. alternating between two antibiotics) in order to identify the factors that favor the sensitive fraction of the commensal flora. Growth parameters for competing bacterial strains were estimated from the combined in vitro pharmacodynamic effect of two antimicrobials using the relationship between concentration and net bacterial growth rate. Predictions of in vivo bacterial growth were generated by a mathematical model of the competitive growth of multiple strains of Escherichia coli.. Simulation studies showed that sequential use of tetracycline and ampicillin reduced the level of double resistance, when compared to the combination treatment. The effect of the cycling frequency (how frequently antibiotics are alternated in a sequential treatment) of the two drugs was dependent upon the order in which the two drugs were used.. Sequential treatment was more effective in preventing the growth of resistant strains when compared to the combination treatment. The cycling frequency did not play a role in suppressing the growth of resistant strains, but the specific order of the two antimicrobials did. Predictions made from the study could be used to redesign multidrug treatment strategies not only for intramuscular treatment in pigs, but also for other dosing routes.

Topics: Ampicillin; Animals; Anti-Bacterial Agents; Bacteria; Bacterial Load; Disease Models, Animal; Drug Resistance, Multiple, Bacterial; Drug Therapy, Combination; Escherichia coli; Escherichia coli Infections; Injections, Intramuscular; Intestines; Microbial Sensitivity Tests; Swine; Tetracycline

Sex differences are a well-known phenomenon in Alzheimer's disease (AD), with women having a higher risk for AD than men. Many AD mouse models display a similar sex-dependent pattern, with females showing earlier cognitive deficits and more severe neuropathology than males. However, whether those differences are relevant to human disease is unclear. Here we show that in AD mouse models that overexpress amyloid precursor protein (APP) under control of the prion protein promoter (PrP), female transgenic mice have higher APP expression than males, complicating interpretations of the role of sex-related factors in such models. By contrast, in a tTa:APPsi model, in which APP expression is driven by the tetracycline transactivator (tTa) from the CaMKIIα promoter, there are no sex-related differences in expression or processing of APP. In addition, the levels of Aβ dimers and tetramers, as well as Aβ peptide accumulation, are similar between sexes. Behavioral testing demonstrated that both male and female tTa:APPsi mice develop age-dependent deficits in spatial recognition memory and conditional freezing to context. These cognitive deficits were accompanied by habituation-associated hyperlocomotion and startle hyper-reactivity. Significant sex-related dimorphisms were observed, due to females showing earlier onsets of the deficits in conditioned freezing and hyperlocomotion. In addition, tTa:APPsi males but not females demonstrated a lack of novelty-induced activation. Both males and females showed atrophy of the dentate gyrus (DG) of the dorsal hippocampus, associated with widening of the pyramidal layer of the CA1 area in both sexes. Ventral DG was preserved. Sex-related differences were limited to the DG, with females showing more advanced degeneration than males. Collectively, our data show that the tTa:APPsi model is characterized by a lack of sex-related differences in APP expression, making this model useful in deciphering the mechanisms of sex differences in AD pathogenesis. Sex-related dimorphisms observed in this model under conditions of equal APP expression between sexes suggest a higher sensitivity of females to the effects of APP and/or Aβ production.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Atrophy; Conditioning, Psychological; Dentate Gyrus; Disease Models, Animal; Fear; Female; Humans; Locomotion; Male; Mice; Mice, Transgenic; Models, Biological; Mutation; Presenilin-1; Recognition, Psychology; Sex Factors; Tetracycline

Targeting the expression of genes has emerged as a potentially viable therapeutic approach to human disease. In Alzheimer's disease, therapies that silence the expression of tau could be a viable strategy to slow disease progression.. We produced a novel strain of transgenic mice that could be used to assess the efficacy of gene knockdown therapies for human tau, in live mice. We designed a tetracycline-regulated transgene construct in which the cDNA for human tau was fused to ubiquitin and to luciferase to create a single fusion polyprotein, termed TUL.. When expressed in brain, the TUL polyprotein was cleaved by ubiquitin-processing enzymes to release the luciferase as an independent protein, separating the half-life of luciferase from the long-lived tau protein. Treatment of bigenic tTA/TUL mice with doxycycline produced rapid declines in luciferase levels visualized by in vivo imaging and ex vivo enzyme measurement.. This new mouse model can be used as a discovery tool in optimizing gene targeting therapeutics directed to reduce human tau mRNA levels.

Topics: Animals; Brain; Disease Models, Animal; Doxycycline; Gene Silencing; Genetic Therapy; Humans; Luciferases; Mice, Transgenic; RNA, Messenger; tau Proteins; Tauopathies; Tetracycline; Ubiquitin

To date a variety of non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) mouse models have been developed that mimic human lung cancer. Chemically induced or spontaneous lung cancer in susceptible inbred strains has been widely used, but the more recent genetically engineered somatic mouse models recapitulate much better the genotype-phenotype correlations found in human lung cancer. Additionally, improved orthotopic transplantation of primary human cancer tissue fragments or cells into lungs of immune-compromised mice can be valuable tools for preclinical research such as antitumor drug tests. Here we give a short overview of most somatic mouse models for lung cancer that are currently in use. We accompany each different model with a description of its practical use and application for all major lung tumor types, as well as the intratracheal injection or direct injection of fresh or freeze-thawed tumor cells or tumor cell lines into lung parenchyma of recipient mice. All here presented somatic mouse models are based on the ability to (in) activate specific alleles at a time, and in a tissue-specific cell type, of choice. This spatial-temporal controlled induction of genetic lesions allows the selective introduction of main genetic lesions in an adult mouse lung as found in human lung cancer. The resulting conditional somatic mouse models can be used as versatile powerful tools in basic lung cancer research and preclinical translational studies alike. These distinctively advanced lung cancer models permit us to investigate initiation (cell of origin) and progression of lung cancer, along with response and resistance to drug therapy. Cre/lox or FLP/frt recombinase-mediated methods are now well-used techniques to develop tissue-restricted lung cancer in mice with tumor-suppressor gene and/or oncogene (in)activation. Intranasal or intratracheal administration of engineered adenovirus-Cre or lentivirus-Cre has been optimized for introducing Cre recombinase activity into pulmonary tissues, and we discuss here the different techniques underlying these applications. Concomitant with Cre/Flp recombinase-based models are the tetracycline (Tet)-inducible bitransgenic systems in which presence or absence of doxycycline can turn the expression of a specific oncogene on or off. The use of several Tet-inducible lung cancer models for NSCLC is presented here in which the reversal of oncogene expression led to complete tumor regression and provided us wi

Topics: Animals; Cell Line, Tumor; Cell Transformation, Neoplastic; Cryopreservation; Disease Models, Animal; DNA Nucleotidyltransferases; Doxycycline; Drinking Water; Female; Humans; Integrases; Lung; Lung Neoplasms; Male; Mice; Mice, Transgenic; Tamoxifen; Tetracycline

Tetracycline induces microvesicular steatosis, which has a poor long-term prognosis and a higher risk of steatohepatitis development compared with macrovesicular steatosis. Recent gene expression studies indicated that tetracycline treatment affects the expression of many genes associated with fatty acid transport and esterification. In this study, we investigated the role of fatty acid transport and esterification in tetracycline-induced steatosis. Intracellular lipid accumulation and the protein expression of fatty acid translocase (FAT or CD36) and diacylglycerol acyltransferase (DGAT) 2 were increased in both mouse liver and HepG2 cells treated with tetracycline at 50 mg/kg (intraperitoneal injection, i.p.) and 100 μM, respectively. Tetracycline increased the cellular uptake of boron-dipyrromethene-labeled C16 fatty acid, which was abolished by CD36 RNA interference. Oleate-induced cellular lipid accumulation was further enhanced by co-incubation with tetracycline. Tetracycline downregulated extracellular signal-regulated kinase (ERK) phosphorylation, which negatively regulated DGAT2 expression. U0126, a specific ERK inhibitor, also increased DGAT2 expression and cellular lipid accumulation. DGAT1 and 2 knock-down with specific small interfering (si)-RNA completely abrogated the steatogenic effect of tetracycline in HepG2 cells. Taken together, our data showed that tetracycline induces lipid accumulation by facilitating fatty acid transport and triglyceride esterification by upregulating CD36 and DGAT2, respectively.

Topics: Animals; Biological Transport; CD36 Antigens; Diacylglycerol O-Acyltransferase; Disease Models, Animal; Esterification; Extracellular Signal-Regulated MAP Kinases; Fatty Acids; Hep G2 Cells; Hepatocytes; Humans; Liver; Male; Mice, Inbred ICR; Non-alcoholic Fatty Liver Disease; Protein Kinase Inhibitors; RNA Interference; Tetracycline; Transfection; Up-Regulation

Amyloid plaques composed of β-amyloid (Aβ) protein are a pathological hallmark of Alzheimer's disease. We here report the generation and characterization of a novel transgenic mouse model of Aβ toxicity. The rTg9191 mice harbor a transgene encoding the 695 amino-acid isoform of human amyloid precursor protein (APP) with the Swedish and London mutations (APPNLI) linked to familial Alzheimer's disease, under the control of a tetracycline-response element, as well as a transgene encoding the tetracycline transactivator, under the control of the promoter for calcium-calmodulin kinase IIα. In these mice, APPNLI is expressed at a level four-fold that of endogenous mouse APP and its expression is restricted to forebrain regions. Transgene expression was suppressed by 87% after two months of doxycycline administration. Histologically, we showed that (1) Aβ plaques emerged in cerebral cortex and hippocampus as early as 8 and 10.5-12.5 months of age, respectively; (2) plaque deposition progressed in an age-dependent manner, occupying up to 19% of cortex at ~25 months of age; and (3) neuropathology--such as abnormal neuronal architecture, tau hyperphosphorylation and misfolding, and neuroinflammation--was observed in the vicinity of neuritic plaques. Biochemically, we determined total Aβ production at varied ages of mice, and we showed that mice produced primarily fibrillar Aβ assemblies recognized by conformation-selective OC antibodies, but few non-fibrillar oligomers (e.g., Aβ*56) detectable by A11 antibodies. Finally, we showed that expression of the tetracycline transactivator resulted in reduced brain weight and smaller dentate-gyrus size. Collectively, these data indicate that rTg9191 mice may serve as a model for studying the neurological effects of the fibrillar Aβ assemblies in situ.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Cerebral Cortex; Disease Models, Animal; Doxycycline; Female; Hippocampus; Humans; Male; Mice; Mice, Transgenic; Plaque, Amyloid; Prosencephalon; Tetracycline

Numerous studies have indicated dental pulp stem cells (DPSCs) potency to differentiate into several types of cell lineages. Oligodendrocyte lineage transcription factor 2 (OLIG2) plays an important role in the oligodendrogenic pathway. In this study, a tetracycline (Tet)-inducible system expressing OLIG2 gene was transfected into human DPSCs to direct their differentiation toward oligodendrocyte progenitor cells (OPCs). Following induction, the expression of stage-specific markers was studied by Reverse Transcription quantitative Polymerase Chain Reaction (RT-qPCR), immunocytochemistry and western blotting. In the following, the cells were transplanted into the mouse model of local sciatic demyelination damage by lysolecithin. Recovery of lysolecithin-induced lesions in sciatic nerve was studied by treadmill exercise, von Frey filament test and hind paw withdrawal in response to a thermal stimulus. Improvement of behavioral symptoms was efficiently observed from the second week to the sixth week post-transplantation. Our findings showed that exogenous expression of the OLIG2 gene by a Tet-regulated system could be used as an efficient way to induce the differentiation of DPSCs into functional oligodendrocytes. Meanwhile, the DPSC-derived OPCs have relevant therapeutic potential in the animal model of sciatic nerve injury and therefore might represent a valuable tool for stem cell-based therapy in inflammatory and degenerative diseases of the peripheral and central nervous systems (CNSs).

Topics: Animals; Basic Helix-Loop-Helix Transcription Factors; Cell Differentiation; Cells, Cultured; Dental Pulp; Disease Models, Animal; Gene Expression; Humans; Lysophosphatidylcholines; Male; Mice; Mice, Inbred BALB C; Motor Activity; Nerve Regeneration; Nerve Tissue Proteins; Oligodendrocyte Transcription Factor 2; Oligodendroglia; Protein Synthesis Inhibitors; Sciatic Neuropathy; Stem Cell Transplantation; Stem Cells; Tetracycline; Time Factors

The brain dopaminergic (DA) system is involved in fine tuning many behaviors and several human diseases are associated with pathological alterations of the DA system such as Parkinson's disease (PD) and drug addiction. Because of its complex network integration, detailed analyses of physiological and pathophysiological conditions are only possible in a whole organism with a sophisticated tool box for visualization and functional modification.. Here, we have generated transgenic mice expressing the tetracycline-regulated transactivator (tTA) or the reverse tetracycline-regulated transactivator (rtTA) under control of the tyrosine hydroxylase (TH) promoter, TH-tTA (tet-OFF) and TH-rtTA (tet-ON) mice, to visualize and genetically modify DA neurons. We show their tight regulation and efficient use to overexpress proteins under the control of tet-responsive elements or to delete genes of interest with tet-responsive Cre. In combination with mice encoding tet-responsive luciferase, we visualized the DA system in living mice progressively over time.. These experiments establish TH-tTA and TH-rtTA mice as a powerful tool to generate and monitor mouse models for DA system diseases.

Topics: Animals; Disease Models, Animal; Dopaminergic Neurons; Gene Expression; Gene Expression Regulation; Gene Targeting; Genetic Vectors; Humans; Luminescent Measurements; Mice; Mice, Transgenic; Optical Imaging; Promoter Regions, Genetic; Tetracycline; Trans-Activators; Tyrosine 3-Monooxygenase

Despite recovery of hemodynamics by fluid resuscitation after hemorrhage, development of the systemic inflammatory response and multiple organ dysfunction syndromes can nonetheless lead to death. Minocycline and doxycycline are tetracycline derivatives that are protective in models of hypoxic, ischemic, and oxidative stress. Our aim was to determine whether minocycline and doxycycline protect liver and kidney and improve survival in a mouse model of hemorrhagic shock and resuscitation.. Mice were hemorrhaged to 30 mmHg for 3 h and then resuscitated with shed blood followed by half the shed volume of lactated Ringer's solution containing tetracycline (10 mg/kg), minocycline (10 mg/kg), doxycycline (5 mg/kg), or vehicle. For pretreatment plus posttreatment, drugs were administered intraperitoneally prior to hemorrhage followed by second equal dose in Ringer's solution after blood resuscitation. Blood and tissue were harvested after 6 h.. Serum alanine aminotransferase (ALT) increased to 1,988 and 1,878 U/L after posttreatment with vehicle and tetracycline, respectively, whereas minocycline and doxycycline posttreatment decreased ALT to 857 and 863 U/L. Pretreatment plus posttreatment with minocycline and doxycycline also decreased ALT to 849 and 834 U/L. After vehicle, blood creatinine increased to 134 µM, which minocycline and doxycycline posttreatment decreased to 59 and 56 µM. Minocycline and doxycycline pretreatment plus posttreatment decreased creatinine similarly. Minocycline and doxycycline also decreased necrosis and apoptosis in liver and apoptosis in both liver and kidney, the latter assessed by TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling) and caspase 3 activation. Lastly after 4.5 h of hemorrhage followed by resuscitation, minocycline and doxycycline (but not tetracycline) posttreatment improved 1-week survival from 38% (vehicle) to 69% and 67%, respectively.. Minocycline and doxycycline were similarly protective when given before as after blood resuscitation and might therefore have clinical efficacy to mitigate liver and kidney injury after resuscitated hemorrhage.

Topics: Alanine Transaminase; Animals; Apoptosis; Biomarkers; Caspase 3; Creatinine; Cytoprotection; Disease Models, Animal; Doxycycline; Fluid Therapy; Hemodynamics; Kidney; Liver; Male; Mice, Inbred C57BL; Minocycline; Multiple Organ Failure; Necrosis; Protective Agents; Resuscitation; Shock, Hemorrhagic; Tetracycline; Time Factors

The polyglutamine (polyQ)-containing protein ataxin-3 (AT3) triggers the neurodegenerative disease spinocerebellar ataxia type 3 (SCA3) when its polyQ tract is expanded beyond a critical length. This results in protein aggregation and generation of toxic oligomers and fibrils. Currently, no effective treatment is available for such and other polyQ diseases. Therefore, plenty of investigations are being carried on to assess the mechanism of action and the therapeutic potential of anti-amyloid agents. The polyphenol compound epigallocatechin-3-gallate (EGCG) and tetracycline have been shown to exert some effect in preventing fibrillogenesis of amyloidogenic proteins. Here, we have incubated an expanded AT3 variant with either compound to assess their effects on the aggregation pattern. The process was monitored by atomic force microscopy and Fourier transform infrared spectroscopy. Whereas in the absence of any treatment, AT3 gives rise to amyloid β-rich fibrils, whose hallmark is the typical glutamine side-chain hydrogen bonding, when incubated in the presence of EGCG it generated soluble, SDS-resistant aggregates, much poorer in β-sheets and devoid of any ordered side-chain hydrogen bonding. These are off-pathway species that persist until the latest incubation time and are virtually absent in the control sample. In contrast, tetracycline did not produce major alterations in the structural features of the aggregated species compared with the control, but substantially increased their solubility. Both compounds significantly reduced toxicity, as shown by the MTT assay in COS-7 cell line and in a transgenic Caenorhabditis elegans strain expressing in the nervous system an AT3 expanded variant in fusion with GFP.

Topics: Amyloid; Animals; Ataxin-3; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Catechin; Cell Survival; Chlorocebus aethiops; COS Cells; Disease Models, Animal; Gene Expression; Green Fluorescent Proteins; Humans; Hydrogen Bonding; Machado-Joseph Disease; Microscopy, Atomic Force; Nerve Tissue Proteins; Neuroprotective Agents; Protein Aggregates; Recombinant Fusion Proteins; Spectroscopy, Fourier Transform Infrared; Tetracycline

This study evaluated whether growing rats were appropriate animal models of glucocorticoid-induced osteoporosis. The 3-month-old male rats were treated with either vehicle or prednisone acetate at 1.5, 3.0, and 6.0 mg/kg/day by oral gavage, respectively. All rats were injected with tetracycline and calcein before sacrificed for the purpose of double in vivo labeling. Biochemistry, histomorphometry, mechanical test, densitometry, micro-CT, histology, and component analysis were performed. We found that prednisone treatments dose dependently decreased body weight, serum biomarkers, biomechanical markers, bone formation, and bone resorption parameters in both tibial and femoral trabecular bone without trabecular bone loss. We also found that significant bone loss happened in femoral cortical bone in the glucocorticoid-treated rats. The results suggested that prednisone not only inhibited bone formation, but also inhibited bone resorption which resulted in poor bone strength but with no cancellous bone loss in growing rats. These data also suggested that the effects of glucocorticoid on bone metabolism were different between cortical bone and trabecular bone, and different between tibia and femur. Growing rats may be a glucocorticoid-induced osteoporosis animal model when evaluated the effects of drugs upon juvenile patients exposed to GC for a long time.

Topics: Acetates; Animals; Biomarkers; Biomechanical Phenomena; Body Weight; Bone Resorption; Densitometry; Disease Models, Animal; Dose-Response Relationship, Drug; Fluoresceins; Glucocorticoids; Male; Osteoporosis; Prednisone; Principal Component Analysis; Rats; Rats, Sprague-Dawley; Stress, Mechanical; Tetracycline; Time Factors; X-Ray Microtomography

The main aims of this study are (i) the development of an antibiotic complexed with multivalent ion, which can allow sustained release of the antibiotic without any additional matrix or difficult process and (ii) the feasibility study of the ion-complexed antibiotic as a therapeutic technique for peritonitis treatment. An ion-complexed antibiotic is prepared by simple mixing of two aqueous solutions containing an ionized (water-soluble) drug (tetracycline) and a multivalent counter ionic compound. The ion-complexed antibiotic shows a continuous release of the antibiotic up to 21 days, and thus prolonged anti-bacterial effect by gradual ionic exchange between the multivalent ions in the complex and same-charged monovalent ions in surrounding medium. From the in vivo animal study using a cecum perforated peritonitis mouse model, the ion-complexed antibiotic group shows sufficient anti-bacterial effect and thus effectively treat the peritonitis because of the extermination of the contaminated enteric bacteria in the peritoneum during wound healing of injury cecum (by the sustained release of antibiotic from the ion complex). These results suggest that the ion-complexed antibiotic system may be promising for the effective treatment of the peritonitis caused by frequent gastrointestinal defect in clinical fields.

Topics: Animals; Anti-Bacterial Agents; Delayed-Action Preparations; Disease Models, Animal; Feasibility Studies; Ion Exchange; Ions; Mice; Mice, Inbred C57BL; NIH 3T3 Cells; Peritonitis; Tetracycline; Time Factors

Cardiovascular toxicity is a major challenge for the pharmaceutical industry and predictive screening models to identify and eliminate pharmaceuticals with the potential to cause cardiovascular toxicity in humans are urgently needed. In this study, taking advantage of the transparency of larval zebrafish, Danio rerio, we assessed cardiovascular toxicity of seven known human cardiotoxic drugs (aspirin, clomipramine hydrochloride, cyclophosphamide, nimodipine, quinidine, terfenadine and verapamil hydrochloride) and two non-cardiovascular toxicity drugs (gentamicin sulphate and tetracycline hydrochloride) in zebrafish using six specific phenotypic endpoints: heart rate, heart rhythm, pericardial edema, circulation, hemorrhage and thrombosis. All the tested drugs were delivered into zebrafish by direct soaking and yolk sac microinjection, respectively, and cardiovascular toxicity was quantitatively or qualitatively assessed at 4 and 24 h post drug treatment. The results showed that aspirin accelerated the zebrafish heart rate (tachycardia), whereas clomipramine hydrochloride, cyclophosphamide, nimodipine, quinidine, terfenadine and verapamil hydrochloride induced bradycardia. Quinidine and terfenadine also caused atrioventricular (AV) block. Nimodipine treatment resulted in atrial arrest with much slower but regular ventricular heart beating. All the tested human cardiotoxic drugs also induced pericardial edema and circulatory disturbance in zebrafish. There was no sign of cardiovascular toxicity in zebrafish treated with non-cardiotoxic drugs gentamicin sulphate and tetracycline hydrochloride. The overall prediction success rate for cardiotoxic drugs and non-cardiotoxic drugs in zebrafish were 100% (9/9) as compared with human results, suggesting that zebrafish is an excellent animal model for rapid in vivo cardiovascular toxicity screening. The procedures we developed in this report for assessing cardiovascular toxicity in zebrafish were suitable for drugs delivered by either soaking or microinjection.

Topics: Abnormalities, Drug-Induced; Animals; Aspirin; Cardiotoxins; Clomipramine; Cyclophosphamide; Disease Models, Animal; Edema; Gentamicins; Heart Diseases; Heart Rate; Heart Ventricles; Larva; Microinjections; Nimodipine; Pericardium; Quinidine; Terfenadine; Tetracycline; Toxicity Tests; Verapamil; Yolk Sac; Zebrafish

The discovery and optimization of a new class of bacterial topoisomerase (DNA gyrase and topoisomerase IV) inhibitors binding in the ATP domain are described. A fragment molecule, 1-ethyl-3-(2-pyridyl)urea, provided sufficiently potent enzyme inhibition (32 μM) to prompt further analogue work. Acids and acid isosteres were incorporated at the 5-pyridyl position of this fragment, bridging to a key asparagine residue, improving enzyme inhibition, and leading to measurable antibacterial activity. A CF3-thiazole substituent at the 4-pyridyl position improved inhibitory potency due to a favorable lipophilic interaction. Promising antibacterial activity was seen versus the Gram-positive pathogens Staphylococcus aureus and Streptococcus pneumoniae and the Gram-negative pathogens Haemophilus influenzae and Moraxella catarrhalis . Precursor metabolite incorporation and mutant analysis studies support the mode-of-action, blockage of DNA synthesis by dual target topoisomerase inhibition. Compound 35 was efficacious in a mouse S. aureus disease model, where a 4.5-log reduction in colony forming units versus control was demonstrated.

Topics: Adenosine Triphosphate; Animals; Anti-Bacterial Agents; Bacteria; Disease Models, Animal; DNA Topoisomerases, Type II; Dose-Response Relationship, Drug; Drug Discovery; Mice; Microbial Sensitivity Tests; Models, Molecular; Molecular Structure; Staphylococcal Infections; Structure-Activity Relationship; Topoisomerase II Inhibitors; Urea

Intracranial hemorrhage in preterm neonates may result in neonatal mortality and functional disabilities, but its pathogenic mechanisms are poorly defined and better therapies are needed. We used a tetracycline-regulated transgenic system to test whether the induction of vascular endothelial growth factor (VEGF) in the germinal matrix leads to intracranial hemorrhage. This genetic strategy initially induced a dense network of loosely adjoined endothelial cells and pericytes near lateral ventricles, similar to the immature vascular rete in human fetal brains. Yet, this rich vascular network transformed into low-vasculature patches correlated with hemorrhage and caspase-3 activation near birth. Gene expression and biochemical analyses suggested that downstream mediators of VEGF in this network include transcriptional factors ETS1 and HIF2α (hypoxia-inducible factor 2α), components of the PDGFβ (platelet-derived growth factor β) and TGFβ (transforming growth factor-β) receptor signaling pathways, matrix metalloproteinase-9 (MMP-9), and cathepsins. Prenatal administration of glucocorticoids markedly reduced mortality and cerebral hemorrhage in mutant animals, as in human neonates. This protective effect was not due to blocking vasculogenesis, but was instead associated with inhibition of neurovascular proteases, notably MMP-9, cathepsin B, and caspase-3. Collectively, these results support a causative role of VEGF in perinatal cerebral hemorrhage and implicate its downstream proteases as potential therapeutic targets.

Topics: Animals; Animals, Newborn; Betamethasone; Caspase 3; Cathepsin B; Cerebral Hemorrhage; Disease Models, Animal; Embryo, Mammalian; Enzyme Activation; Enzyme Induction; Gene Expression Profiling; Glucocorticoids; Humans; Matrix Metalloproteinase 9; Mice; Neovascularization, Pathologic; Peptide Hydrolases; Phenotype; Prosencephalon; Protease Inhibitors; Tetracycline; Vascular Endothelial Growth Factor A

The tetracycline regulatory system provides a tractable strategy to interrogate the role of oncogenes in the initiation and maintenance of tumorigenesis through both spatial and temporal control of expression. This approach has several potential advantages over conventional methods to generate genetically engineered mouse models. First, continuous constitutive overexpression of an oncogene can be lethal to the host impeding further study. Second, constitutive overexpression fails to model adult onset of disease. Third, constitutive deletion does not permit, whereas conditional overexpression of an oncogene enables the study of the consequences of restoring expression of an oncogene back to endogenous levels. Fourth, the conditional activation of oncogenes enables examination of specific and/or developmental state-specific consequences. Hence, by allowing precise control of when and where a gene is expressed, the tetracycline regulatory system provides an ideal approach for the study of putative oncogenes in both the initiation and maintenance of tumorigenesis. In this protocol, we describe the methods involved in the development of a conditional mouse model of MYC-induced T-cell acute lymphoblastic leukemia.

Topics: Animals; Cell Line; Disease Models, Animal; Female; Gene Expression; Gene Expression Regulation, Neoplastic; Gene Targeting; Genetic Vectors; Isografts; Male; Mice; Mice, Transgenic; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Proto-Oncogene Proteins c-myc; Tetracycline

THE AIM OF INVESTIGATION: To study the effect of schemes second line quadruple therapy on the state of gastric mucosal barrier and NO formation in experimental ulcer.. The study included 60 white male rats weighing 150-190 gr, mixed population. The effect of the standard second-line regimens on the content of the fractions of insoluble glycoproteins, on indicators of NO formation and anaerobic glycolysis in gastric mucosal tissue in experimental ulcer.. Quadruple therapy consisting of omeprazole, de-nol, amoxicillin and tetracycline stimulates mechanisms of protective barrier, which has a positive effect on the mechanisms of NO formation. Scheme with omeprazole, de-nol, tetracycline and metronidazole inhibits the synthesis of mucosal barrier, the key mechanisms of NO formation.. In the plan of correction of mechanisms of cytoprotection in the gastric mucosal tissue quadruple therapy with omeprazole, de ethanol, amoxicillin, and tetracycline is considered to be effective.

Topics: Amoxicillin; Animals; Anti-Bacterial Agents; Anti-Ulcer Agents; Disease Models, Animal; Drug Therapy, Combination; Gastric Mucosa; Male; Nitric Oxide; Omeprazole; Organometallic Compounds; Rats; Stomach Ulcer; Tetracycline

Elevated concentrations of plasminogen activator inhibitor-1 (PAI-1) are associated with pleural injury, but its effects on pleural organization remain unclear. A method of adenovirus-mediated delivery of genes of interest (expressed under a cytomegalovirus promoter) to rabbit pleura was developed and used with lacZ and human (h) PAI-1. Histology, β-galactosidase staining, Western blotting, enzymatic and immunohistochemical analyses of pleural fluids (PFs), lavages, and pleural mesothelial cells were used to evaluate the efficiency and effects of transduction. Transduction was selective and limited to the pleural mesothelial monolayer. The intrapleural expression of both genes was transient, with their peak expression at 4 to 5 days. On Day 5, hPAI-1 (40-80 and 200-400 nM of active and total hPAI-1 in lavages, respectively) caused no overt pleural injury, effusions, or fibrosis. The adenovirus-mediated delivery of hPAI-1 with subsequent tetracycline-induced pleural injury resulted in a significant exacerbation of the pleural fibrosis observed on Day 5 (P = 0.029 and P = 0.021 versus vehicle and adenoviral control samples, respectively). Intrapleural fibrinolytic therapy (IPFT) with plasminogen activators was effective in both animals overexpressing hPAI-1 and control animals with tetracycline injury alone. An increase in intrapleural active PAI-1 (from 10-15 nM in control animals to 20-40 nM in hPAI-1-overexpressing animals) resulted in the increased formation of PAI-1/plasminogen activator complexes in vivo. The decrease in intrapleural plasminogen-activating activity observed at 10 to 40 minutes after IPFT correlates linearly with the initial concentration of active PAI-1. Therefore, active PAI-1 in PFs affects the outcome of IPFT, and may be both a biomarker of pleural injury and a molecular target for its treatment.

Topics: Adenoviridae; Animals; Disease Models, Animal; Epithelium; Gene Expression; Humans; Lac Operon; Plasminogen Activator Inhibitor 1; Pleura; Rabbits; Recombinant Proteins; Tetracycline; Thrombolytic Therapy; Transduction, Genetic

Myc is a pleiotropic transcription factor that is involved in many cellular activities relevant to carcinogenesis, including hepatocarcinogenesis. The zebrafish has been increasingly used to model human diseases and it is particularly valuable in helping to identify common and conserved molecular mechanisms in vertebrates. Here we generated a liver tumor model in transgenic zebrafish by liver-specific expression of mouse Myc using a Tet-On system. Dosage-dependent induction of Myc expression specifically in the liver was observed in our Myc transgenic zebrafish, TO(Myc), and the elevated Myc expression caused liver hyperplasia, which progressed to hepatocellular adenoma and carcinoma with prolonged induction. Next generation sequencing-based transcriptomic analyses indicated that ribosome proteins were overwhelmingly upregulated in the Myc-induced liver tumors. Cross-species analyses showed that the zebrafish Myc model correlated well with Myc transgenic mouse models for liver cancers. The Myc-induced zebrafish liver tumors also possessed molecular signatures highly similar to human those of hepatocellular carcinoma. Finally, we found that a small Myc target gene set of 16 genes could be used to identify liver tumors due to Myc upregulation. Thus, our zebrafish model demonstrated the conserved role of Myc in promoting hepatocarcinogenesis in all vertebrate species.

Topics: Animals; Animals, Genetically Modified; Carcinoma, Hepatocellular; Disease Models, Animal; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Liver; Liver Neoplasms; Liver Neoplasms, Experimental; Mammals; Mice; Mice, Transgenic; Neoplasm Staging; Proto-Oncogene Proteins c-myc; Reproducibility of Results; Sequence Analysis, RNA; Tetracycline; Zebrafish

Expression of a multidrug resistance transporter renders bacterial cells resistant to a variety of drugs. The major facilitator superfamily (MFS) comprises the largest group of bacterial multidrug transporters. There are over 20 MFS efflux pumps annotated on the genome of Vibrio cholerae, but little is known about their functions and regulation. In this study, five MFS efflux pumps were characterised, each of which is associated with a divergently transcribed putative LysR-type transcriptional regulator (MfsR). It was found that each of these MFS structural genes is regulated by the corresponding MfsR regulator. Deletion of these five mfs genes results in increased susceptibility to tetracycline and crude bile as well as a colonisation defect in an infant mouse colonisation model. Moreover, tetracycline and unknown intestinal signals could serve as co-inducers for the MfsR regulators. These data suggest that MFS efflux pumps are important both for antimicrobial resistance and V. cholerae pathogenesis.

Topics: Animals; Anti-Bacterial Agents; Bile Acids and Salts; Cholera; Disease Models, Animal; Drug Resistance, Multiple, Bacterial; Gene Deletion; Gene Expression Regulation, Bacterial; Membrane Transport Proteins; Mice; Tetracycline; Transcription Factors; Vibrio cholerae; Virulence

Machado-Joseph disease (MJD), also known as Spinocerebellar Ataxia type 3, is an inherited dominant autosomal neurodegenerative disorder. An expansion of Cytosine-Adenine-Guanine (CAG) repeats in the ATXN3 gene is translated as an expanded polyglutamine domain in the disease protein, ataxin-3. Selective neurodegeneration in MJD is evident in several subcortical brain regions including the cerebellum. Mitochondrial dysfunction has been proposed as a mechanism of neurodegeneration in polyglutamine disorders. In this study, we used different cell models and transgenic mice to assess the importance of mitochondria on cytotoxicity observed in MJD. Transiently transfected HEK cell lines with expanded (Q84) ataxin-3 exhibited a higher susceptibility to 3-nitropropionic acid (3-NP), an irreversible inhibitor of mitochondrial complex II. Increased susceptibility to 3-NP was also detected in stably transfected PC6-3 cells that inducibly express expanded (Q108) ataxin-3 in a tetracycline-regulated manner. Moreover, cerebellar granule cells from MJD transgenic mice were more sensitive to 3-NP inhibition than wild-type cerebellar neurons. PC6-3 (Q108) cells differentiated into a neuronal-like phenotype with nerve growth factor (NGF) exhibited a significant decrease in mitochondrial complex II activity. Mitochondria from MJD transgenic mouse model and lymphoblast cell lines derived from MJD patients also showed a trend toward reduced complex II activity. Our results suggest that mitochondrial complex II activity is moderately compromised in MJD, which may designate a common feature in polyglutamine toxicity.

Topics: Animals; Ataxin-3; Cell Death; Cell Line; Cell Line, Transformed; Cells, Cultured; Cerebellum; Disease Models, Animal; HEK293 Cells; Humans; Machado-Joseph Disease; Mice; Mice, Transgenic; Mitochondria; Mitochondrial Membranes; Nerve Tissue Proteins; Neurons; Nitro Compounds; Nuclear Proteins; Peptides; Propionates; Repressor Proteins; Tetracycline

Polymeric ultra-thin films (nanosheets) possess unique properties that make them suitable materials for various biomedical applications. In our previous study, we assessed the use of an antibiotic (tetracycline, TC)-loaded nanosheet (or "TC-nanosheet") for the treatment of gastrointestinal tissue defects. The nanosheet consisted of three functional layers: layer-by-layer nanosheet as a stable platform, TC as an antimicrobial agent with autofluorescence for tracing, and a poly(vinyl acetate) nanosheet to act as a protecting layer. The TC-nanosheet has high flexibility, adhesive strength and transparency. Here, we evaluated the effectiveness of the TC-nanosheet in preventing full thickness burn-wound infections. In an in vivo study, murine dorsal skin was injured by full-thickness burns and then infected with Pseudomonas aeruginosa (P. aeruginosa), a common bacterium causing burn-associated infections. The wound site was treated either with a TC-nanosheet, TC-unloaded nanosheet or left untreated. Wound management was facilitated by the high transparency of the TC-nanosheet. The TC-nanosheet significantly improved burn-wound infection by P. aeruginosa in mice. Indeed, all mice treated with the TC-nanosheet survived, whereas the other treatment groups displayed increased rates of mortality due to bacterial infection. According to histological analyses and viable bacterial counting in the liver (bacterial translocation), the TC-nanosheets were able to prevent not only the local inflammation but also systemic inflammation. We conclude that the TC-nanosheet can act as an effective treatment for full-thickness burn-wound infection. Hence, the TC-nanosheet is a promising therapeutic tool for burn-wound management in severely burn-injured patients.

Topics: Animals; Anti-Bacterial Agents; Burns; Colony Count, Microbial; Disease Models, Animal; Liver; Lung; Male; Mice; Mice, Inbred C57BL; Microbial Viability; Nanoparticles; Skin; Tetracycline; Treatment Outcome; Wound Infection

The tet-off system has been widely used to create transgenic models of neurological disorders including Alzheimer's, Parkinson's, Huntington's, and prion disease. The utility of this system lies in the assumption that the tetracycline transactivator (TTA) acts as an inert control element and does not contribute to phenotypes under study. Here we report that neuronal expression of TTA can affect hippocampal cytoarchitecture and behavior in a strain-dependent manner. While studying neurodegeneration in two tet-off Alzheimer's disease models, we unexpectedly discovered neuronal loss within the dentate gyrus of single transgenic TTA controls. Granule neurons appeared most sensitive to TTA exposure during postnatal development, and doxycycline treatment during this period was neuroprotective. TTA-induced degeneration could be rescued by moving the transgene onto a congenic C57BL/6J background and recurred on reintroduction of either CBA or C3H/He backgrounds. Quantitative trait analysis of B6C3 F2 TTA mice identified a region on Chromosome 14 that contains a major modifier of the neurodegenerative phenotype. Although B6 mice were resistant to degeneration, they were not ideal for cognitive testing. F1 offspring of TTA C57BL/6J and 129X1/SvJ, FVB/NJ, or DBA/1J showed improved spatial learning, but TTA expression caused subtle differences in contextual fear conditioning on two of these backgrounds, indicating that strain and genotype can interact independently under different behavioral settings. All model systems have limitations that should be recognized and mitigated where possible; our findings stress the importance of mapping the effects caused by TTA alone when working with tet-off models.

Topics: Amyloid beta-Protein Precursor; Analysis of Variance; Animals; Anti-Bacterial Agents; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Chromosome Mapping; Conditioning, Psychological; Dentate Gyrus; Disease Models, Animal; Doxycycline; Exploratory Behavior; Fear; Female; Male; Maze Learning; Mental Disorders; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Mice, Transgenic; Mutation; Neurotoxicity Syndromes; Species Specificity; tau Proteins; Tetracycline; Trans-Activators

Urinary excretion of tritiated tetracycline ((3)H-TC) and (41)Ca tracers was validated as reflecting skeletal disappearance of these bone-seeking tracers as a direct measure of bone turnover following ovariectomy in rats.. Tritiated tetracycline ((3)H-TC) and Ca tracers have been used to measure bone resorption in animal models, but urinary excretion of these labels has not been directly compared to skeletal turnover. We aimed to evaluate the use of bone-seeking labels by comparing label release into urine with label in the skeleton when bone turnover was perturbed following ovariectomy.. Sixty-four 6-month-old ovariectomized (OVX) rats were randomized to one of eight groups in a 2 × 4 design that differed in time of (3)H-TC and (41)Ca administration following ovariectomy (1 month, when bone turnover would be accelerated following estrogen depletion or 3 months when bone loss due to OVX had slowed down) and time of euthanasia (1 week, 1 month, 3 months, and 6 months post-dose). Twenty-four-hour urine pools over two to four consecutive days and total skeleton were collected and recovered for the assessment of (3)H-TC and (41)Ca.. Urinary (3)H-TC levels reflected skeletal (3)H-TC levels (r = 0.93; p < 0.0001) over a wide range of bone turnover rates in response to an intervention. Urinary (41)Ca and (3)H-TC excretion were highly correlated (r = 0.95, p < 0.0001).. This study confirms that bone-seeking label excretion into the urine directly measures bone turnover.

Topics: Animals; Biomarkers; Bone Remodeling; Bone Resorption; Calcium Radioisotopes; Disease Models, Animal; Female; Femur; Lumbar Vertebrae; Ovariectomy; Rats; Rats, Sprague-Dawley; Reproducibility of Results; Tetracycline; Tibia; Tritium

We have previously demonstrated that excessive mitochondrial reactive oxygen species caused by mutations in the SDHC subunit of Complex II resulted in premature death in C. elegans and Drosophila, tumors in mouse cells and infertility in transgenic mice. We now report the generation and initial characterization of conditional transgenic mice (Tet-mev-1) using our uniquely developed Tet-On/Off system, which equilibrates transgene expression to endogenous levels. The mice experienced mitochondrial respiratory chain dysfunction that induced reactive oxygen species overproduction. The mitochondrial oxidative stress resulted in excessive apoptosis leading to low birth weight and growth retardation in the neonatal developmental phase in Tet-mev-1 mice.

Topics: Animals; Animals, Newborn; Disease Models, Animal; Gene Expression Regulation; Growth Disorders; Humans; Infant, Low Birth Weight; Infant, Newborn; Mice; Mice, Transgenic; Mitochondria; Mitochondrial Diseases; Mutation; NIH 3T3 Cells; Reactive Oxygen Species; Succinate Dehydrogenase; Tetracycline; Transgenes

Short hairpin RNAs (shRNAs) are versatile tools for analyzing loss-of-function phenotypes in vitro and in vivo. However, their use for studying genes involved in proliferation and survival, which are potential therapeutic targets in cancer and other diseases, is confounded by the strong selective advantage of cells in which shRNA expression is inefficient. We therefore developed a toolkit that combines Tet-regulated miR30-shRNA technology, robust transactivator expression and two fluorescent reporters to track and isolate cells with potent target knockdown. We demonstrated that this system improves the study of essential genes and was sufficiently robust to eradicate aggressive cancer in mice by suppressing a single gene. Further, we applied this system for in vivo negative-selection screening with pooled shRNAs and propose a streamlined, inexpensive workflow that will facilitate the use of RNA interference (RNAi) for the identification and evaluation of essential therapeutic targets.

Topics: Animals; Biotechnology; Cell Line, Tumor; Cell Proliferation; Cell Survival; Disease Models, Animal; Female; Fluorescent Dyes; Gene Expression Regulation, Neoplastic; Genes, Reporter; Humans; Leukemia, Monocytic, Acute; Mice; Mice, Inbred C57BL; Mice, Transgenic; RNA Interference; RNA, Small Interfering; Tetracycline; Trans-Activators

To test the hypothesis that in vivo transgene expression mediated by single intra-articular injection of adeno-associated virus serotype 2 (AAV2) persists within intra-articular tissues 1 year post-injection and can be externally controlled using an AAV2-based tetracycline-inducible gene regulation system containing the tetracycline response element (TRE) promoter.. Sprague Dawley rats received intra-articular injections of AAV2-cytomegalovirus (CMV)-enhanced green fluorescent protein (GFP) and AAV2-CMV-luciferase (Luc) into their right and left knees, respectively. Luciferase expression was evaluated over 1 year using bioluminescence imaging. After sacrifice, tissues were analyzed for GFP+ cells by fluorescent microscopy. To study external control of intra-articular AAV-transgene expression, another set of rats was co-injected with AAV2-TRE-Luc and AAV2-CMV-reverse-tetracycline-controlled transactivator (rtTA) into the right knees, and AAV2-CMV-Luc and AAV2-CMV-rtTA into the left knees. Rats received oral doxycycline (Dox), an analog of tetracycline, for 7 days. Luciferase expression was assessed by bioluminescence imaging.. Luciferase expression was localized to the injected joint and persisted throughout the 1-year study period. Abundant GFP+ cells were observed within intra-articular soft tissues. Transgene expression in AAV2-TRE-Luc injected joints was upregulated by oral administration of Dox, and downregulated following its removal, at 14 days and 13 months post-AAV injection.. This longitudinal in vivo study shows that sustained and stable AAV-mediated intra-articular transgene expression can be achieved through a single intra-articular injection and can be controlled using a tetracycline-controlled inducible AAV system in a normal rat knee model. Highly regulatable long-term intra-articular transgene expression is of potential clinical utility for development of treatment strategies for chronic intra-articular disease processes such as inflammatory and degenerative arthritis.

Topics: Animals; Cartilage, Articular; Dependovirus; Disease Models, Animal; Doxycycline; Gene Expression Regulation; Gene Transfer Techniques; Green Fluorescent Proteins; Hindlimb; Injections, Intra-Articular; Longitudinal Studies; Luciferases; Male; Microscopy, Fluorescence; Rats; Rats, Sprague-Dawley; Tetracycline; Trans-Activators; Transgenes

Understanding the pathogenesis of infectious disease requires the examination and successful integration of parameters related to both microbial virulence and host responses. As a practical and powerful method to control microbial gene expression, including in vivo, the tetracycline-regulatable system has recently gained the favor of many investigative groups. However, some immunomodulatory effects of the tetracyclines, including doxycycline, could potentially limit its use to evaluate host responses during infection. Here we have used a well-established murine model of disseminated candidiasis, which is highly dependent on both the virulence displayed by the fungal cells and on the host immune status, to validate the use of this system. We demonstrate that the pathogenesis of the wild type C. albicans CAF2-1 strain, which does not contain any tet-regulatable element, is not affected by the presence of doxycycline. Moreover levels of key cytokines, chemokines and many other biomarkers, as determined by multi-analyte profiling, remain essentially unaltered by the presence of the antibiotic during infection. Our results indicate that the levels of doxycycline needed to control the tetracycline regulatable promoter gene expression system have no detectable effect on global host responses during candidiasis. Because tet-regulatable systems are now being increasingly used in a variety of pathogenic microorganisms, these observations have wide implications in the field of infectious diseases.

Topics: Animals; Candida albicans; Candidiasis; Chemokines; Cytokines; Disease Models, Animal; Doxycycline; Gene Expression Regulation, Fungal; Host-Pathogen Interactions; Kidney; Mice; Mutation; Promoter Regions, Genetic; Protein Synthesis Inhibitors; Response Elements; Spleen; Tetracycline; Virulence

Bone-specific compounds have been used effectively for the detection of bone mineralization, growth, and morphological changes. These agents typically contain iminodiacetic acid groups that can form complexes with apatite and fluoresce in the visible spectrum. We exploited a subset of these chemical chelators to produce a near-infrared (NIR) optical bone marker for preclinical animal imaging. By conjugating target compounds to IRDye 800CW, we extended the effective fluorescence signal detection to the NIR region without affecting the compound's ability to function as a marker of the mineralization process. Calcein and a tetracycline derivative (BoneTag agent [BT]) bound specifically to differentiated mineralized osteoblast cultures, with the latter exhibiting 6-fold higher signal intensities. Subsequent in vivo testing demonstrated effective skeletal labeling with IRDye 800CW BT. We were able to identify a changing mineralization front in bone sections from (i) normal growing mice injected with IRDye 800CW BT 6weeks prior to the administration of IRDye 680 BT and (ii) an osteoporosis mouse model comparing cortical bone in sham-treated and ovariectomized mice. These results provide evidence that the NIR-labeled BT is effective as a general marker of skeletal features and an indicator of the bone mineralization and remodeling processes.

Topics: Animals; Biomarkers; Bone Remodeling; Calcification, Physiologic; Cell Line; Disease Models, Animal; Fluoresceins; Indoles; Mice; Mice, Nude; Microscopy, Fluorescence; Osteoporosis; Spectroscopy, Near-Infrared; Tetracycline; Whole Body Imaging

In experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis (MS), loss of the blood-brain barrier (BBB) tight junction (TJ) protein claudin-3 correlates with immune cell infiltration into the CNS and BBB leakiness. Here we show that sealing BBB TJs by ectopic tetracycline-regulated expression of the TJ protein claudin-1 in Tie-2 tTA//TRE-claudin-1 double transgenic C57BL/6 mice had no influence on immune cell trafficking across the BBB during EAE and furthermore did not influence the onset and severity of the first clinical disease episode. However, expression of claudin-1 did significantly reduce BBB leakiness for both blood borne tracers and endogenous plasma proteins specifically around vessels expressing claudin-1. In addition, mice expressing claudin-1 exhibited a reduced disease burden during the chronic phase of EAE as compared to control littermates. Our study identifies BBB TJs as the critical structure regulating BBB permeability but not immune cell trafficking into CNS during EAE, and indicates BBB dysfunction is a potential key event contributing to disease burden in the chronic phase of EAE. Our observations suggest that stabilizing BBB barrier function by therapeutic targeting of TJs may be beneficial in treating MS, especially when anti-inflammatory treatments have failed.

Topics: Animals; Blood-Brain Barrier; Cell Movement; Central Nervous System; Claudin-1; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Endothelium, Vascular; Gene Expression Regulation; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Multiple Sclerosis; Receptor, TIE-2; Tetracycline; Tight Junctions

There are few options for prophylaxis after exposure to Bacillus anthracis, especially in children and women of childbearing potential. Faropenem is a beta-lactam in the penem subclass that is being developed as an oral prodrug, faropenem medoxomil, for the treatment of respiratory tract infections. Faropenem was shown to have in vitro activity against B. anthracis strains that variably express the bla1 beta-lactamase (MIC range,

Topics: Animals; Anthrax; Anti-Bacterial Agents; Bacillus anthracis; beta-Lactamases; beta-Lactams; Blood Proteins; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Inhalation Exposure; Mice; Mice, Inbred BALB C; Models, Biological

The aim of this study was to compare angiogenesis and osteogenesis occurring within 8.0 mm diaphyseal defects created in canine tibiae treated using autograft or a biodegradable bone scaffold. All tibiae were reamed to 7.0 mm and fixed with a 6.5-mm statically locked intramedullary nail. Each of the 18 canines as allotted to one of three treatment groups: (1) left empty (N = 5), (2) treated with iliac crest autograft (N = 6), or (3) treated with a PLGA/calcium phosphate biodegradable scaffold (N = 7). Fluorescent markers were given at successive time periods: calcein green at 6 weeks, xylenol orange at 9 weeks, and tetracycline at 11 and 14 weeks. Animals were sacrificed at 15 weeks and their legs were perfused with a radio opaque compound. Samples were analyzed using Micro CT, bright-field microscopy and fluorescent microscopy. Scaffold samples were found to have significantly greater bone formation (p = 0.015) and blood vessel formation (p < 0.001) at their osteotomy sites than autograft samples. Bone formation rate in the periosteum was significantly greater in the autograft samples than the scaffold samples for all time periods. Bone formation at the osteotomy site was found to be significantly greater when associated with greater blood vessel formation (p = 0.026). The PLGA/calcium phosphate biodegradable scaffold we have employed supports angiogenesis within a segmental tibial defect that has adequate soft tissue coverage.

Topics: Absorbable Implants; Animals; Bone Substitutes; Bone Transplantation; Calcium Phosphates; Disease Models, Animal; Dogs; Fluoresceins; Fluorescent Dyes; Fracture Fixation, Intramedullary; Fracture Healing; Ilium; Lactic Acid; Neovascularization, Physiologic; Osteogenesis; Osteotomy; Phenols; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Radiography; Sulfoxides; Tetracycline; Tibial Fractures; Time Factors; Tissue Scaffolds; Transplantation, Homologous; Xylenes

Mycoplasma hominis, the first mycoplasma of human origin to be isolated, has been associated with several diseases, notably bacterial vaginosis, pelvic inflammatory disease, prematurity and puerperal fever. The mouse model does not mimic closely these features of human disease, but has some notable features. Given intravaginally to mice, M. hominis does not colonize unless the mice have been pre-treated with oestradiol. As shown here, endogenous hormone has no part to play because removal of the ovaries does not interfere with vaginal colonization. Persistent colonization occurs in hysterectomized mice so that organisms in the upper tract, which are sometimes found, are not responsible, by retrograde leakage, for those in the lower tract. Organisms in the lower tract can be eliminated by treating mice with a tetracycline, or progesterone or by natural resolution. Elimination by whatever means results in a rather weak immunity to recolonization. In contrast, intravenous inoculation of viable, and particularly killed, M. hominis organisms results in strong resistance to recolonization. This is, in part, genetically influenced, being seen in mice of strain BALB/c but not of strain CBA. Resistance is inversely proportional to the presence and titre of M. hominis specific serum antibody. The possible role of cell-mediated immunity is discussed.

Topics: Animals; Disease Models, Animal; Estradiol; Female; Humans; Hysterectomy; Mice; Mice, Inbred BALB C; Mice, Inbred CBA; Mycoplasma hominis; Mycoplasma Infections; Progesterone; Tetracycline; Vaginosis, Bacterial

The accumulation and deposition of amyloid beta (Aβ) peptide in extracellular dense plaques in the brain is a key phase in Alzheimer's disease (AD). Small oligomeric forms of Aβ are responsible for the toxicity and the early cognitive impairment observed in patients before the amyloid plaque deposits appear. It is essential for the development of an efficient cure for AD to identify compounds that interfere with Aβ aggregation, counteracting the molecular mechanisms involved in conversion of the monomeric amyloid protein into oligomeric and fibrillar forms. Tetracyclines have been proposed for AD therapy, although their effects on the aggregation of Aβ protein, particularly their ability to interact in vivo with the Aβ oligomers and/or aggregates, remain to be understood. Using transgenic Caenorhabditis elegans as a simplified invertebrate model of AD, we evaluated the ability of tetracyclines to interfere with the sequence of events leading to Aβ proteotoxicity. The drugs directly interact with the Aβ assemblies in vivo and reduce Aβ oligomer deposition, protecting C. elegans from oxidative stress and the onset of the paralysis phenotype. These effects were specific, dose-related and not linked to any antibiotic activity, suggesting that the drugs might offer an effective therapeutic strategy to target soluble Aβ aggregates.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Brain; Caenorhabditis elegans; Disease Models, Animal; Dose-Response Relationship, Drug; Oxidative Stress; Protein Synthesis Inhibitors; Tetracycline

Iron is essential for a wide range of cellular processes. Here we show that the bZIP-type regulator HapX is indispensable for the transcriptional remodeling required for adaption to iron starvation in the opportunistic fungal pathogen Aspergillus fumigatus. HapX represses iron-dependent and mitochondrial-localized activities including respiration, TCA cycle, amino acid metabolism, iron-sulfur-cluster and heme biosynthesis. In agreement with the impact on mitochondrial metabolism, HapX-deficiency decreases resistance to tetracycline and increases mitochondrial DNA content. Pathways positively affected by HapX include production of the ribotoxin AspF1 and siderophores, which are known virulence determinants. Iron starvation causes a massive remodeling of the amino acid pool and HapX is essential for the coordination of the production of siderophores and their precursor ornithine. Consistent with HapX-function being limited to iron depleted conditions and A. fumigatus facing iron starvation in the host, HapX-deficiency causes significant attenuation of virulence in a murine model of aspergillosis. Taken together, this study demonstrates that HapX-dependent adaption to conditions of iron starvation is crucial for virulence of A. fumigatus.

Topics: Adaptation, Psychological; Allergens; Amino Acids; Animals; Anti-Bacterial Agents; Antigens, Plant; Aspergillosis; Aspergillus fumigatus; Basic-Leucine Zipper Transcription Factors; Biomarkers; Blotting, Northern; Disease Models, Animal; DNA, Mitochondrial; Drug Resistance, Fungal; Fungal Proteins; GATA Transcription Factors; Gene Expression Profiling; Gene Expression Regulation, Fungal; Iron Deficiencies; Mice; Oligonucleotide Array Sequence Analysis; Ornithine; Repressor Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Siderophores; Survival Rate; Tetracycline; Virulence

Nonmammalian model systems of infection such as Galleria mellonella (caterpillars of the greater wax moth) have significant logistical and ethical advantages over mammalian models. In this study, we utilize G. mellonella caterpillars to study host-pathogen interactions with the gram-negative organism Acinetobacter baumannii and determine the utility of this infection model to study antibacterial efficacy. After infecting G. mellonella caterpillars with a reference A. baumannii strain, we observed that the rate of G. mellonella killing was dependent on the infection inoculum and the incubation temperature postinfection, with greater killing at 37 degrees C than at 30 degrees C (P = 0.01). A. baumannii strains caused greater killing than the less-pathogenic species Acinetobacter baylyi and Acinetobacter lwoffii (P < 0.001). Community-acquired A. baumannii caused greater killing than a reference hospital-acquired strain (P < 0.01). Reduced levels of production of the quorum-sensing molecule 3-hydroxy-C(12)-homoserine lactone caused no change in A. baumannii virulence against G. mellonella. Treatment of a lethal A. baumannii infection with antibiotics that had in vitro activity against the infecting A. baumannii strain significantly prolonged the survival of G. mellonella caterpillars compared with treatment with antibiotics to which the bacteria were resistant. G. mellonella is a relatively simple, nonmammalian model system that can be used to facilitate the in vivo study of host-pathogen interactions in A. baumannii and the efficacy of antibacterial agents.

Topics: Acinetobacter baumannii; Acinetobacter Infections; Animals; Disease Models, Animal; Host-Pathogen Interactions; Moths; Quorum Sensing; Virulence

In order to find sensitive serum markers in non-alcoholic steatohepatitis, liver-specific injury markers were thoroughly examined in mild models of NASH in rats.. Wistar and Sprague-Dawley rats were fed a choline-deficient diet for 4 weeks, and serum activities of liver-specific enzyme markers were examined. In the drug-induced steatohepatitis model, tetracycline (0.4 mmol/kg) was given i.p. to rats and the course of hepatotoxicity was evaluated with serum markers, together with the accumulation of total lipid and thiobarbituric acid-reactive substances in the liver.. In Wistar rats, serum activities of most enzymes tested were significantly increased. In Sprague-Dawley rats, in contrast, the serum level of ornithine carbamyltransferase and glutamate dehydrogenase were markedly elevated in the choline-deficient diet group compared with the control diet groups, whereas other markers were not significantly increased. In the tetracycline-induced steatohepatitis model, the extent of the increase was much higher in mitochondrial markers and the peak of the increase in these markers corresponded with the increase of hepatic total lipid and thiobarbituric acid-reactive substance.. These observations show that serum mitochondrial enzyme markers are potent markers for non-alcoholic steatohepatitis in rats and are possibly applicable to humans.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Biomarkers; Choline Deficiency; Diet; Disease Models, Animal; Enzymes; Fatty Liver; Glutamate Dehydrogenase; Injections, Intraperitoneal; Lipid Peroxidation; Liver; Male; Mitochondria, Liver; Mitochondrial Proteins; Ornithine Carbamoyltransferase; Rats; Rats, Sprague-Dawley; Rats, Wistar; Severity of Illness Index; Tetracycline; Thiobarbituric Acid Reactive Substances; Time Factors; Tumor Necrosis Factor-alpha; Up-Regulation

Cell cycle proteins are elevated in the brain of patients and in transgenic models of Alzheimer's disease (AD), suggesting that aberrant cell cycle re-entry plays a key role in this disorder. However, the precise relationship between cell cycle reactivation and the hallmarks of AD, amyloid-beta (Abeta) plaques and tau-laden neurofibrillary tangles, remains unclear. We sought to determine whether cell cycle reactivation initiates in direct response to Abeta and tau accumulation or whether it occurs as a downstream consequence of neuronal death pathways. Therefore, we used a triple transgenic mouse model of AD (3xTg-AD) that develops plaques and tangles, but does not exhibit extensive neuronal loss, whereas to model hippocampal neuronal death a tetracycline-regulatable transgenic model of neuronal ablation (CaM/Tet-DT(A) mice) was used. Cell-cycle protein activation was determined in these two models of neurodegeneration, using biochemical and histological approaches. Our findings indicate that Cdk4, PCNA and phospho-Rb are significantly elevated in CaM/Tet-DT(A) mice following neuronal death. In contrast, no significant activation of cell-cycle proteins occurs in 3xTg-AD mice versus non-transgenic controls. Taken together, our data indicate that neuronal cell cycle reactivation is not a prominent feature induced by Abeta or tau pathology, but rather appears to be triggered by acute neuronal loss.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Cell Cycle Proteins; Cell Death; Cyclin-Dependent Kinase 4; Denervation; Disease Models, Animal; Histones; Mice; Mice, Transgenic; Neurons; Proliferating Cell Nuclear Antigen; Retinoblastoma Protein; tau Proteins; Tetracycline

Four groups of six specific pathogen-free (SPF) pigs were inoculated intranasally with Actinobacillus pleuropneumoniae serotype 2 and treated with either enrofloxacin, tetracycline or penicillin at the onset of clinical disease, or left untreated. A fifth group was left uninoculated. The inoculated control and the penicillin-treated groups developed severe disease, but the groups treated with enrofloxacin and tetracycline recovered rapidly. All the inoculated pigs, except those treated with enrofloxacin developed serum antibodies to A pleuropneumoniae. On day 28, all five groups were challenged with A pleuropneumoniae without any subsequent treatment. The previously uninoculated control group and the enrofloxacin-treated group developed severe disease, but the three seropositive groups remained unaffected.

Topics: Actinobacillus Infections; Actinobacillus pleuropneumoniae; Animals; Anti-Bacterial Agents; Antibodies, Bacterial; Disease Models, Animal; Enrofloxacin; Euthanasia, Animal; Fluoroquinolones; Penicillins; Respiratory Tract Diseases; Specific Pathogen-Free Organisms; Swine; Swine Diseases; Tetracycline

Peroxisome proliferators-activated receptor alpha (PPARalpha) and oxidative stress are two important pathological factors in non-alcoholic fatty liver disease (NAFLD). Tetracycline-induced fatty liver was partly due to the disturbance of mitochondrial fatty acids beta-oxidation regulated by PPARalpha. Bicyclol was found to protect against high fat diet-induced fatty liver through modulating PPARalpha and clearing reactive oxygen species (ROS). The present study was performed to further investigate the effect of bicyclol on tetracycline-induced fatty liver and related mechanism in mice. Bicyclol (75, 150, 300 mg/kg) was given orally three times in two consecutive days. Tetracycline (200 mg/kg) was injected intraperitoneally 1h after the last administration of bicyclol. Oxidative stress, mitochondrial function, PPARalpha and its target genes were evaluated by biochemical and RT-PCR analysis. The activity of CYP4A was assessed by liquid chromatography/mass spectrometry (LC/MS) method. Bicyclol significantly protected against tetracycline-induced fatty liver by reducing the accumulation of hepatic lipids and elevation of serum aminotransferase. In addition, bicyclol remarkably alleviated the over-production of thiobarbituric acid-reactive substance. The reduced activity of mitochondrial respiratory chain (MRC) complexes I and IV and mitochondrial permeability transition (MPT) were also improved by bicyclol. Furthermore, bicyclol inhibited the decrease of PPARalpha expression and its target genes, including long-chain acyl CoA dehydrogenase (LCAD), acetyl CoA oxidase (AOX) and CYP4A at mRNA and enzyme activity level. Bicyclol protected against tetracycline-induced fatty liver mainly through modulating the disturbance of PPARalpha pathway and ameliorating mitochondrial function.

Topics: Acyl-CoA Dehydrogenase, Long-Chain; Acyl-CoA Oxidase; Administration, Oral; Alanine Transaminase; Animals; Aspartate Aminotransferases; Biphenyl Compounds; Cytochrome P-450 CYP2E1; Cytochrome P-450 CYP4A; Disease Models, Animal; Electron Transport Complex I; Electron Transport Complex IV; Fatty Acids; Fatty Liver; Lipid Peroxidation; Liver; Male; Mice; Mice, Inbred ICR; Mitochondria, Liver; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Oxidative Stress; PPAR alpha; Protective Agents; Tetracycline; Time Factors

This paper aimed to explore three-dimensionally cultured hepatocytes for testing drug-induced nonalcoholic steatohepatitis. Gel entrapped rat hepatocytes were applied for investigation of the tetracycline-induced steatohepatitis, while hepatocyte monolayer was set as a control. The toxic responses of hepatocytes were systematically evaluated by measuring cell viability, liver-specific function, lipid accumulation, oxidative stress, adenosine triphosphate content and mitochondrial membrane potential. The results suggested that gel entrapped hepatocytes showed cell death after 96 h of tetracycline treatment at 25 muM which is equivalent to toxic serum concentration in rats, while hepatocyte monolayer showed cell death at a high dose of 200 muM. The concentration-dependent accumulation of lipid as well as mitochondrial damage were regarded as two early events for tetracycline hepatotoxicity in gel entrapment culture due to their detectability ahead of subsequent increase of oxidative stress and a final cell death. Furthermore, the potent protection of fenofibrate and fructose-1,6-diphosphate were evidenced in only gel entrapment culture with higher expressions on the genes related to beta-oxidation than hepatocyte monolayer, suggesting the mediation of lipid metabolism and mitochondrial damage in tetracycline toxicity. Overall, gel entrapped hepatocytes in three-dimension reflected more of the tetracycline toxicity in vivo than hepatocyte monolayer and thus was suggested as a more relevant system for evaluating steatogenic drugs.

Topics: Animals; Anti-Bacterial Agents; Cell Culture Techniques; Cell Survival; Disease Models, Animal; Dose-Response Relationship, Drug; Fatty Liver; Gels; Hepatocytes; Lipid Peroxidation; Male; Mitochondrial Membranes; Oxidative Stress; Rats; Rats, Sprague-Dawley; Tetracycline

A radial segmental defect model of a rabbit was used to study the restoration effect on defects treated with chitosan-coated pressed calcium sulfate pellets combined with recombinant human bone morphogenetic protein-2 (rhBMP-2), coated pressed calcium sulfate pellets, and uncoated pressed calcium sulfate pellets. Nothing was implanted in the control group. After 4, 8, and 12 weeks, the results indicated that coated pressed calcium sulfate pellets combined with rhBMP-2 and coated pressed calcium sulfate pellets facilitated new bone formation on defected bones and that, particularly, the coated pressed calcium sulfate pellets combined with rhBMP-2 was more effective than the coated pressed calcium sulfate pellet. Histologic and tetracycline fluorimetric findings showed that the osteogenesis mechanism of chitosan-coated pressed calcium sulfate pellets is membrane bone formation, and the pellets showed slightly slower resorption that closely coincides with the growth rate of new bone.

Topics: Absorbable Implants; Animals; Bone Density; Bone Diseases; Bone Marrow; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Bone Substitutes; Calcification, Physiologic; Calcium Sulfate; Chitosan; Coated Materials, Biocompatible; Connective Tissue; Diaphyses; Disease Models, Animal; Fluorescent Dyes; Fluorometry; Humans; Osteogenesis; Rabbits; Radius; Recombinant Proteins; Stress, Mechanical; Tetracycline; Time Factors; Transforming Growth Factor beta

Activating mutations of the oncogene K-ras are found in one third of all human cancers. Much of our knowledge on K-ras signal transduction and its influence on tumor initiation and progression come from in vitro studies with cell lines. However, mouse models of human cancer allow a much more faithful recapitulation of the human disease, and the in vivo perspective is crucial for our understanding of neoplasia. In recent years, several new murine models for K-ras-induced tumorigenesis have been described. They allow new insights into the specific role that oncogenic K-ras proteins play in different solid tumors, and they permit the molecular dissection of the pathways that are initiated by somatic mutations in subsets of cells. Key advances have been made by the use of tissue-specific and inducible control of expression, which is achieved by the Cre/loxP technology or the tetracycline system. From these sophisticated models, a common picture emerges: the effects of K-ras on tumor initiation depend strongly on the cellular context, and different tissues vary in their susceptibility to K-ras transformation.

Topics: Animals; Crosses, Genetic; Disease Models, Animal; Gene Expression Regulation, Neoplastic; Gene Transfer Techniques; Genes, ras; Genes, Tumor Suppressor; Intestinal Mucosa; Intestinal Neoplasms; Lung Neoplasms; Mice; Mice, Transgenic; Mutation; Neoplasms; Neoplastic Stem Cells; Organ Specificity; Pancreatic Neoplasms; Protein Synthesis Inhibitors; ras Proteins; Tetracycline; Transgenes

A major goal of epilepsy research is to understand the molecular and functional basis of seizure genesis. A human GABA(A) gamma2 gene mutation (R43Q) is associated with generalized epilepsy. Introduction of this mutation into a mouse by gene targeting recapitulates the human phenotype demonstrating a strong genotype to phenotype link. GABA(A) receptors play a role in the moment-to-moment control of brain function and also on the long-term wiring of the brain by directing neuronal development. Our objective was to determine whether developmental expression of the mutation alters seizure susceptibility later in life.. A tetracycline-based conditional model for activation of a hypomorphic Q43 disease allele was created and validated. Seizure susceptibility was assessed using the subcutaneous pentylenetetrazole model.. Seizure susceptibility was significantly reduced in mice where the Q43 allele was suppressed during development.. These results demonstrate that a human epilepsy-causing mutation impacts network stability during a critical developmental period. These data suggest that identification of presymptomatic children may provide a window for therapeutic intervention before overt symptoms are observed, potentially altering the course of epileptogenesis.

Topics: Animals; Brain; Brain Chemistry; Convulsants; Disease Models, Animal; Epilepsy; gamma-Aminobutyric Acid; Genetic Predisposition to Disease; Humans; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Nerve Net; Neural Inhibition; Pentylenetetrazole; Receptors, GABA-A; Tetracycline

Diarrhea is the gastrointestinal disease most frequently encountered in captive rhesus macaques. The precise pathogenic mechanisms underlying chronic diarrhea in nonhuman primates are not well understood, but a persistent inflammatory component has been implicated strongly. This study evaluated the inflammatory changes in the colon of macaques with diarrhea and assessed the efficacy of a 10-d course of tylosin in a cohort of 21 animals with chronic diarrhea. Stool quality was evaluated daily, and fecal consistency was scored. Colonoscopies were performed; biopsy samples were characterized histologically and assayed for expression of TNFalpha mRNA. Blood samples collected pre-, mid-, and post-treatment were assayed for C-reactive protein (CRP). The results indicated that 63% of the animals receiving tylosin showed improvement in stool quality, compared with 10% in the sham-treated group. Histologically, 82% of animals in the tylosin-treated group had a reduction in the severity of colonic lesions post-treatment, compared with 40% of animals in the sham group. The amount of TNFalpha mRNA before treatment did not differ from that afterward in either tylosin- or sham-treated animals. CRP levels serially decreased in tylosin-treated monkeys; the average post-treatment CRP value for tylosin-treated animals was 11.96 +/- 3.86 microg/ml compared with 26.48 +/- 4.86 microg/ml for sham-treated controls. In conclusion, tylosin significantly improved the fecal consistency score, significantly decreased colonic inflammation, and significantly decreased serum CRP levels post-treatment in rhesus macaques with chronic diarrhea.

Topics: Animals; Anti-Bacterial Agents; C-Reactive Protein; Chronic Disease; Colonoscopy; Cytokines; Diarrhea; Disease Models, Animal; Dog Diseases; Dogs; Feces; Gene Expression Regulation; Macaca mulatta; Metronidazole; Prednisone; Primate Diseases; RNA, Messenger; Tetracycline; Tumor Necrosis Factor-alpha; Tylosin

The discovery of the endosymbiont Wolbachia, which has a mutualistic relationship with filarial nematodes, and its importance in filarial parasite biology has provided a lead for developing novel chemotherapeutic agents against human filariasis. Wolbachia also appears to be involved in immunopathological responses as well as adverse reactions after antifilarial therapy. The aim of the present study was to explore the potential of administering anti-Wolbachial therapy before antifilarial treatment to improve the filaricidal efficacy of the present-day filaricide diethylcarbamazine. An additional objective was to minimize host inflammatory reactions using a rodent model Mastomys coucha and Meriones unguiculatus infected with human lymphatic filariid Brugia malayi. We observed: (1) a 40-day treatment schedule of tetracycline alone resulted in delayed reduction in microfilaraemia and a low degree of macrofilaricidal efficacy; (2) tetracycline therapy followed by 100 mg/kg diethylcarbamazine (DEC) x5 days led to marked reduction in microfilaraemia from day 48 onward after initiation of treatment. The combination treatment also brought about approximately 70% death of adult B. malayi and sterilization of 82.3% of the surviving female worms, thus exhibiting remarkable enhancement in the antifilarial activity of DEC; (3) tissue inflammatory reactions and pathogenesis were significantly reduced as observed by histopathology, and peritoneal macrophage mediated oxidative burst shown by fluorescence-activated cell sorting (FACS) analysis using dichlorofluorescein diacetate (DCF-DA); and (4) the characteristic filarial antigen-specific and mitogen-specific cellular unresponsiveness was significantly reversed, possibly due to marked clearance of microfilaraemia. It is therefore advisable to give an anti-Wolbachial antibiotic trial before starting antifilarial therapy to achieve maximum benefits.

Topics: Animals; Anti-Bacterial Agents; Brugia malayi; Diethylcarbamazine; Disease Models, Animal; Drug Administration Schedule; Drug Therapy, Combination; Female; Filariasis; Filaricides; Gerbillinae; Host-Parasite Interactions; Humans; Inflammation; Male; Murinae; Tetracycline; Treatment Outcome; Wolbachia

The intricate wound repair process involves the interplay of numerous cells and proteins. Using a porcine full-thickness wound (FTW) healing model, we hypothesized that the ex vivo gene transfer of vascular endothelial growth factor (VEGF)-transfected basal keratinocyte (KC) cell suspensions may generate cross-talk and induce matrix formation, angiogenesis, and accelerated healing. Moreover, to regulate overexpression of isoform 165 of VEGF and its effect on healing, we introduced a tetracycline (TC)-inducible gene switch in the expression plasmid. Autologous basal KCs were cultivated from the porcine donor and transfected using cationic liposomes. A dose-response curve was established to determine optimal activation of the gene switch by TC. In vivo, FTWs were treated with VEGF-transfected KCs and controls. Wound fluids were collected daily and examined using enzyme-linked immunosorbent assay. Biopsies were evaluated using hematoxylin and eosin and immunostaining for fibronectin, CD144, and lectin BS-1. In vitro, highest regulable VEGF165-expression was obtained with 1 microg/mL of TCs. In vivo, after induction of the gene switch by adding 1 microg/mL of TCs to the FTW, we obtained upregulated VEGF165 levels and enhanced fibronectin deposition and found more endothelial cell tubular formations and higher rates of reepithelialization than in controls. This ex vivo gene transfer model may serve as a platform for vascular induction in full-thickness tissue repair.

Topics: Animals; Anti-Bacterial Agents; Cells, Cultured; Disease Models, Animal; Endothelial Cells; Extracellular Matrix; Fibronectins; Gene Expression; Keratinocytes; Neovascularization, Physiologic; Swine; Tetracycline; Transfection; Transplantation, Autologous; Vascular Endothelial Growth Factor A; Wound Healing; Wounds and Injuries

We studied the mechanisms and dynamics of the development of resistance to ceftazidime (CAZ) alone or combined with tobramycin (TOB) or ciprofloxacin (CIP) in vitro and in vivo (using a mouse model of lung infection with human antibiotic regimens). Pseudomonas aeruginosa strain PAO1 and its hypermutable derivative PAODeltamutS were used, and the results were compared with those previously obtained with CIP, TOB, and CIP plus TOB (CIP-TOB) under the same conditions. An important (200-fold) amplification of the number of resistant mutant cells was documented for PAODeltamutS-infected mice that were under CAZ treatment compared to the number for mice that received placebo, whereas the median number of resistant mutant cells was below the detection limits for mice infected by PAO1. These results were intermediate between the high amplification with CIP (50,000-fold) and the low amplification with TOB (10-fold). All CAZ-resistant single mutant cells selected in vitro or in vivo hyperproduced AmpC. On the other hand, the three combinations studied were found to be highly effective in the prevention of in vivo resistance development in mice infected with PAODeltamutS, although the highest therapeutic efficacy (in terms of mortality and total bacterial load reduction) compared to those of the individual regimens was obtained with CIP-TOB and the lowest was with CAZ-CIP. Nevertheless, mutant cells that were resistant to the three combinations tested were readily selected in vitro for PAODeltamutS (mutation rates from 1.2 x 10(-9) to 5.8 x 10(-11)) but not for PAO1, highlighting the potential risk for antimicrobial resistance development associated with the presence of hypermutable strains, even when combined therapy was used. All five independent CAZ-TOB-resistant PAODeltamutS double mutants studied presented the same resistance mechanism (AmpC hyperproduction plus an aminoglycoside resistance mechanism not related to MexXY), whereas four different combinations of resistance mechanisms were documented for the five CAZ-CIP-resistant double mutants.

Topics: Animals; Anti-Bacterial Agents; Ceftazidime; Ciprofloxacin; Disease Models, Animal; Drug Resistance, Microbial; Drug Synergism; Drug Therapy, Combination; Female; Humans; In Vitro Techniques; Lung; Mice; Mice, Inbred C57BL; Microbial Sensitivity Tests; Mutation; Pseudomonas aeruginosa; Pseudomonas Infections; Tobramycin

A line of double-transgenic mice that develop neoplasms arising primarily in the pancreas was established. In these mice, the oncogene SV40 T antigen (Tag) was detected in the pancreas with and without the control of Tet-on system. The transgenic mice that developed pancreatic tumors as early as 20 weeks of age showed hypoglycemia on a blood glucose test. Pathological and immunohistochemical characterizations demonstrated that the tumors belonged to neuroendocrine neoplasms arising from pancreatic islets. A change in IGFs/IGF-1R signaling pathway was detected using real-time PCR analysis. A potential association between the IGFs/IGF-1R system and SV40Tag was studied to further explain the cancerogenesis of the double-transgenic mice by Western blot analysis and immunoprecipitation experiments. The results suggest that a Tag transgenic mice model could be used to study the molecular mechanism of the tumorigenesis of islets.

Topics: Animals; Antigens, Polyomavirus Transforming; Blood Glucose; Disease Models, Animal; Insulin Receptor Substrate Proteins; Insulinoma; Mice; Mice, Transgenic; Neuroendocrine Tumors; Pancreatic Neoplasms; Phosphoproteins; Somatomedins; Tetracycline

Lipodystrophies are syndromes of adipose tissue degeneration associated with severe defects in lipid and glucose homeostasis. We report here the generation and analysis of Pparg(ldi), a targeted allele that confers conditional dominant lipodystrophy in mice. The Pparg(ldi) allele was generated by insertion of the Tet activator (tTA) and a tTA-regulated Flag-Pparg1 transgene into the Pparg gene. Unexpectedly, tTA elicits mild lipodystrophy, insulin resistance, and dyslipidemia, and the Flag-PPARgamma1 transgene surprisingly exacerbates these traits. Doxycycline can both completely prevent and reverse these phenotypes, providing a mouse model of inducible lipodystrophy. Embryonic fibroblasts from either Pparg(ldi/+) or the phenotypically similar aP2-nSrebp1c (Sr) transgenic mice undergo robust adipogenesis, suggesting that neither strain develops lipodystrophy because of defective adipocyte differentiation. In addition, Pparg(ldi/+) adipose tissue shares extensive gene expression aberrations with that of Sr mice, authenticating the phenotype at the molecular level and revealing a common expression signature of lipodystrophic fat. Thus, the Pparg(ldi/+) mouse provides a conditional animal model for studying lipodystrophy and its associated physiology and gene expression.

Topics: Adipogenesis; Alleles; Animals; Disease Models, Animal; Doxycycline; Fibroblasts; Gene Expression; Insulin Resistance; Lipodystrophy; Mice; Mice, Transgenic; PPAR gamma; Promoter Regions, Genetic; Sterol Regulatory Element Binding Protein 1; Tetracycline; Trans-Activators

Neuronal loss is a major pathological outcome of many common neurological disorders, including ischemia, traumatic brain injury, and Alzheimer disease. Stem cell-based approaches have received considerable attention as a potential means of treatment, although it remains to be determined whether stem cells can ameliorate memory dysfunction, a devastating component of these disorders. We generated a transgenic mouse model in which the tetracycline-off system is used to regulate expression of diphtheria toxin A chain. After induction, we find progressive neuronal loss primarily within the hippocampus, leading to specific impairments in memory. We find that neural stem cells transplanted into the brain after neuronal ablation survive, migrate, differentiate and, most significantly, improve memory. These results show that stem cells may have therapeutic value in diseases and conditions that result in memory loss.

Topics: Analysis of Variance; Animals; Behavior, Animal; Brain Diseases; Bromodeoxyuridine; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Cell Count; Cell Differentiation; Cell Movement; Cell Proliferation; Diphtheria Toxin; Disease Models, Animal; Green Fluorescent Proteins; In Situ Nick-End Labeling; Memory Disorders; Mice; Mice, Transgenic; Neurons; Peptide Fragments; Phosphopyruvate Hydratase; Stem Cell Transplantation; Tetracycline

The hyaluronan receptor CD44 plays an important role in facilitating invasion and metastasis of a variety of tumors, including breast carcinomas. CD44 functions as a bioactive signaling transmitter. Although a number of studies have implicated CD44 in breast tumor invasion, the evidence is still circumstantial. We have developed a tetracycline-regulated CD44s (standard form) system in the weakly metastatic breast cancer cell MCF7, which exhibits low endogenous expression of CD44 and generated a new cell line, MCF7F-B5. Induction of CD44s alone affected the growth characteristics of MCF7F-B5 cells by increasing their abilities to proliferate, migrate, and invade in vitro. In addition, we have identified and validated cortactin as a novel transcriptional target of hyaluronan/CD44s signaling in underpinning breast tumor invasion. To test these observations in vivo, we developed a doxycycline (DOX)-regulated CD44s breast cancer xenograft model. Induction of CD44s did not affect the growth rate or local invasion of the primary tumor. However, although no mice from the +DOX group developed metastasis, 8 of 11 mice from the -DOX group developed secondary tumors to the liver only. Interestingly, metastatic breast tumors expressed high levels of CD44. This study provides in vivo evidence for the role of the standard form of CD44 in promoting breast tumor invasion and metastasis to the liver.

Topics: Animals; Breast Neoplasms; Cell Line, Tumor; Disease Models, Animal; Doxycycline; Female; Hyaluronan Receptors; Liver Neoplasms; Mice; Mice, SCID; Neoplasm Invasiveness; Neoplasm Transplantation; Tetracycline; Transplantation, Heterologous

We report the generation of a tetracycline-regulated (Tet ON) transgenic mouse model for acute and chronic expression of the iron regulatory peptide hepcidin in the liver. We demonstrate that short-term and long-term tetracycline-dependent activation of hepcidin in adult mice leads to hypoferremia and iron-limited erythropoiesis, respectively. This clearly establishes the key role of hepcidin in regulating the extracellular iron concentration. We previously demonstrated that, when expressed early in fetal development, constitutive transgenic hepcidin expression prevented iron accumulation in an Hfe-/- mouse model of hemochromatosis. We now explore the effect of chronic hepcidin expression in adult Hfe-/- mice that have already developed liver iron overload. We demonstrate that induction of chronic hepcidin expression in 2-month-old Hfe-/- mice alters their pattern of cellular iron accumulation, leading to increased iron in tissue macrophages and duodenal cells but less iron in hepatocytes. These hepcidin-induced changes in the pattern of cellular iron accumulation are associated with decreased expression of the iron exporter ferroportin in macrophages but no detectable alteration of ferroportin expression in the hepatocytes. We speculate that this change in iron homeostasis could offer a therapeutic advantage by protecting against damage to parenchymal cells.

Topics: Animals; Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Disease Models, Animal; Doxycycline; Hemochromatosis; Hemochromatosis Protein; Hepcidins; Histocompatibility Antigens Class I; Iron; Membrane Proteins; Mice; Mice, Knockout; Tetracycline

Minocycline, a clinically used tetracycline for over 40 years, crosses the blood-brain barrier and prevents caspase up-regulation. It reduces apoptosis in mouse models of Huntington's disease and familial amyotrophic lateral sclerosis (ALS) and is in clinical trial for sporadic ALS. Because apoptosis also occurs after brain and spinal cord (SCI) injury, its prevention may be useful in improving recovery. We analyzed minocycline's neuroprotective effects over 28 days following contusion SCI and found significant functional recovery compared to tetracycline. Histology, immunocytochemistry, and image analysis indicated statistically significant tissue sparing, reduced apoptosis and microgliosis, and less activated caspase-3 and substrate cleavage. Since our original report in abstract form, others have published both positive and negative effects of minocycline in various rodent models of SCI and with various routes of administration. We have since found decreased tumor necrosis factor-alpha, as well as caspase-3 mRNA expression, as possible mechanisms of action for minocycline's ameliorative action. These results support reports that modulating apoptosis, caspases, and microglia provide promising therapeutic targets for prevention and/or limiting the degree of functional loss after CNS trauma. Minocycline, and more potent chemically synthesized tetracyclines, may find a place in the therapeutic arsenal to promote recovery early after SCI in humans.

Topics: Animals; Anti-Inflammatory Agents; Apoptosis; Caspase 3; Caspase Inhibitors; Caspases; Disease Models, Animal; Enzyme Activation; Female; Gliosis; Injections, Intraperitoneal; Minocycline; Nerve Degeneration; Neurons; Neuroprotective Agents; Protein Synthesis Inhibitors; Rats; Rats, Long-Evans; Rats, Sprague-Dawley; RNA, Messenger; Spinal Cord; Spinal Cord Injuries; Tetracycline; Treatment Outcome; Tumor Necrosis Factor-alpha

The Naja sumatrana cobra can spit venom in defense and may result in permanent blindness. The study sought to determine the efficacy of topical heparin, Haffkine antivenom, tetracycline and dexamethasone.. Male New Zealand White Rabbits were used. Pooled venom was frozen at -30 degrees C. 0.05 mL of 20 times dilute venom was introduced into the conjunctiva, in groups of three rabbits randomly. Heparin at 5000 IU/mL, Haffkine antivenom or saline control was administered repeatedly on each rabbit's eye over 158 minutes, after a specified delay. In other groups, 1% tetracycline, 0.1% dexamethasone or a placebo ointment was applied and repeated at 24 and 48 hours. All the rabbits were assessed after 24, 48, 72 hours, one and two weeks by an ophthalmologist blinded to the treatment arms.. Following ocular envenomation, there was immediate blepharospasm, lacrimal secretions, redness and chemosis; more intense in the normal saline group. The Roper-Hall grades improved, corneas re-epithelialized and inflammation quietened in the heparin and antivenom-treated rabbit eyes compared to controls. Scarring appeared from the first week, but ameliorated in the heparin and antivenom groups. Heparin treatment remained efficacious up to four minutes delay. The tetracycline, dexamethasone and placebo groups had worsening Roper-Hall trends, greater corneal epithelial loss, inflammation and scarring. Combined heparin-tetracycline therapy was as efficacious with heparin alone.. Topical heparin or antivenom therapy significantly improved overall outcomes in rabbit corneas exposed to Naja sumatrana venom, compared to tetracycline, dexamethasone and controls. Heparin treatment remains efficacious up to 4 minutes delay.

Topics: Administration, Topical; Animals; Antivenins; Dexamethasone; Disease Models, Animal; Elapid Venoms; Elapidae; Eye Diseases; Heparin; Male; Ointments; Rabbits; Tetracycline; Treatment Outcome

To create a model in which to study the effects of RAS dysregulation in hematopoietic disease, we developed separate founder lines of transgenic mice, with the tetracycline transactivator (tTA) driven by the Vav hematopoietic promoter in one line and NRASV12 driven by the tetracycline responsive element (TRE2) in the other. When these lines are crossed, doubly transgenic animals uniformly develop a disease similar to human aggressive systemic mastocytosis (ASM) or mast cell leukemia (MCL) when they are between 2 and 4 months of age. Disease is characterized by tissue infiltrates of large, well-differentiated mast cells in the spleen, liver, skin, lung, and thymus. Analysis of bone sections shows small to large foci of similarly well-differentiated mast cells. Results also show that transgene expression and diseases are repressible through the administration of doxycycline in the drinking water of affected animals, indicating that NRASV12 expression is required to initiate and maintain disease in doubly transgenic mice. Our inducible system of transgenes, developed as a model of mutant NRASV12 oncogene-driven myeloid disease, will be useful for studying the role of RAS dysregulation in hematopoietic disease in general and in discrete human diseases, specifically ASM and MCL.

Topics: Animals; Disease Models, Animal; Doxycycline; Gene Expression Regulation; Genes, ras; Leukemia, Mast-Cell; Leukemic Infiltration; Mastocytosis; Mastocytosis, Systemic; Mice; Mice, Transgenic; Response Elements; Tetracycline; Transduction, Genetic

The impact of Helicobacter eradication therapy on the progression or regression of gastric lesions is poorly defined. This study examined the effects of eradication therapy on inflammation, atrophy, metaplasia, dysplasia, and cancer progression.. C57BL/6 mice were infected with Helicobacter felis and received bacterial eradication therapy after 2, 6, or 12 months of infection. The gastric mucosa was examined at early, mid, and late intervals after eradication and graded for histology, expression pattern of alpha-catenin and beta-catenin, and IQGAP1.. Eradication of Helicobacter infection after 2 or 6 months of infection led to a regression of inflammation, restoration of parietal cell mass, and reestablishment of normal architecture. Progression to adenocarcinoma was prevented. Bacterial eradication at 1 year was associated with the reappearance of parietal cells, partial regression of inflammation, and restoration of architecture. Hyperplasia scores significantly improved, and dysplasia did not progress. Infected mice developed antral adenocarcinoma and gastric outlet obstruction by 24 months. Only 30% of the mice receiving bacterial eradication therapy at 12 months developed antral carcinoma. Bacterial eradication at any time during the first year of infection prevented death due to gastric outlet obstruction. The expression pattern of alpha-catenin, beta-catenin, and IQGAP1 varied with cell type and paralleled histologic changes.. Inflammation, metaplasia, and dysplasia are reversible with early eradication therapy; progression of dysplasia was arrested with eradication therapy given as late as 1 year and prevented gastric cancer-related deaths.

Topics: Adenocarcinoma; Animals; Anti-Bacterial Agents; Atrophy; Disease Models, Animal; Gastric Mucosa; Helicobacter felis; Helicobacter Infections; Male; Mice; Mice, Inbred C57BL; Precancerous Conditions; Stomach Neoplasms; Tetracycline

Pleurodesis is a frequently preferred procedure in thoracic surgery, and many factors may affect the process. We aimed to determine whether the administration of systemic diclofenac sodium diminishes the effectiveness of the pleurodesis induced by intrapleural tetracycline in rabbits.. Twelve male New Zealand rabbits that received tetracycline 35 mg/kg intrapleurally were allocated into two groups. The first group (diclofenac group, n = 6) received 2 mg/kg diclofenac sodium intramuscularly for 10 days, and the second group (control group, n = 6) received acetaminophen 30 mg/kg orally for 10 days after the pleurodesis procedure. The rabbits were sacrificed after 28 days, and the pleural spaces were assessed grossly for evidence of pleurodesis and microscopically for evidence of fibrosis, inflammation, and collagenization.. The mean macroscopic pleurodesis score of the diclofenac group was 2.16 +/- 0.40 compared with 2.83 +/- 0.40 in the control group (p = .027). The mean microscopic pleurodesis score of the diclofenac group was 2. 3 +/- 1.03, whereas it was 3.5 +/- 0.54 in the control group (p = .045).. The administration of diclofenac sodium for 10 days following tetracycline pleurodesis reduces the effectiveness of pleurodesis in rabbits.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Diclofenac; Disease Models, Animal; Fibrosis; Male; Pleura; Pleurodesis; Rabbits; Sclerosing Solutions; Tetracycline

Members of the adeno-associated virus (AAV) family are good candidates for the treatment of ocular diseases because of their relative lack of pathogenicity. We studied the effect of intraocular injection of AAV2-viral IL-10 (vIL-10) on retinal S-antigen-induced experimental autoimmune uveoretinitis (EAU) in Lewis rats. We demonstrated that AAV2/2-GFP injected into the vitreous body transduced the iris and ciliary body, or anterior uvea, and the retina. We showed that intravitreal injection of the AAV2/2-tetON-vIL-10 construct achieved detectable levels of vIL-10 mRNA and protein within the eye and was effective in protecting the rat retina against destruction. This protection was dependent on the level of vIL-10 present in the aqueous humor/ vitreous body. Intravitreal injection of the same construct encased within an AAV5 shell, AAV2/5-tetONvIL- 10, did not confer any degree of protection. It appeared that the AAV2/5 vectors did not transduce the anterior uvea, the site at which inflammatory cells first localize in EAU, nor the ganglion cell layer; induced low expression of vIL-10 mRNA; and did not achieve detectable levels of transgene expression in the aqueous humor/vitreous body. Local treatment with AAV2/2-tetON-vIL-10 did not dampen the systemic immune response, as determined by S-antigen-specific lymphocyte proliferation. Our results show that local intravitreal injection of AAV2/2 is an effective means by which to deliver immunoregulatory molecules into the eye during uveitis, a chronic human ocular disease.

Topics: Animals; Aqueous Humor; Arrestin; Autoimmune Diseases; Cell Proliferation; Dependovirus; Disease Models, Animal; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Green Fluorescent Proteins; Humans; Interleukin-10; Lymphocytes; Male; Rats; Rats, Inbred Lew; Retina; Retinitis; Tetracycline; Uveitis

Sepsis causes more than with 215,000 deaths per year in the United States alone. Death can be caused by multiple system organ failure, with the lung, in the form of the acute respiratory distress syndrome (ARDS), often being the first organ to fail. We developed a chronic porcine model of septic shock and ARDS and hypothesized that blocking the proteases neutrophil elastase (NE) and matrix metalloproteinases (MMP-2 and MMP-9) with the modified tetracycline, COL-3, would significantly improve morbidity in this model. Pigs were anesthetized and instrumented for hemodynamic monitoring and were then randomized to one of three groups: control (n = 3), laparotomy only; superior mesenteric artery occlusion (SMA) + fecal blood clot (FC; n = 7), with intraperitoneal placement of a FC; and SMA + FC + COL (n = 5), ingestion of COL-3 12 h before injury. Animals emerged from anesthesia and were monitored and treated with fluids and antibiotics in an animal intensive care unit continuously for 48 h. Serum and bronchoalveolar lavage fluid (BALF) were sampled and bacterial cultures, MMP-2, MMP-9, NE, and multiple cytokine concentrations were measured. Pigs were reanesthetized and placed on a ventilator when significant lung impairment occurred (PaO2/FiO2 < 250). At necropsy, lung water and histology were assessed. All animals in the SMA + FC group developed septic shock evidenced by a significant fall in arterial blood pressure that was not responsive to fluids. Lung injury typical of ARDS (i.e., a fall in lung compliance and PaO2/FiO2 ratio and a significant increase in lung water) developed in this group. Additionally, there was a significant increase in plasma IL-1 and IL-6 and in BALF IL-6, IL-8, IL-10, NE, and protein concentration in the SMA + FC group. COL-3 treatment prevented septic shock and ARDS and significantly decreased cytokine levels in plasma and BALF. COL-3 treatment also significantly reduced NE activity (P < 0.05) and reduced MMP-2 and MMP-9 activity in BALF by 64% and 34%, respectively, compared with the SMA + FC group. We conclude that prophylactic COL-3 prevented the development of ARDS and unexpectedly also prevented septic shock in a chronic insidious onset animal model of sepsis-induced ARDS. The mechanism of this protection is unclear, as COL-3 inhibited numerous inflammatory mediators. Nevertheless, COL-3 significantly reduced the morbidity in a clinically applicable animal model, demonstrating the possibility that COL-3 may be useful in reduc

Topics: Animals; Bronchoalveolar Lavage Fluid; Cytokines; Disease Models, Animal; Female; Inflammation; Interleukin-1; Interleukin-10; Interleukin-6; Interleukin-8; Leukocyte Elastase; Lung; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mesenteric Artery, Superior; Models, Chemical; Oxygen; Peptide Hydrolases; Pulmonary Edema; Respiratory Distress Syndrome; Sepsis; Swine; Tetracycline; Tetracyclines; Time Factors

Wolbachia bacteria, being filarial parasite symbiont have been implicated in a variety of roles, including development, fecundity and the pathogenesis of the filarial infections. Among various strategies used in the treatment of experimental filariasis, the elimination of symbiont Wolbachia seem to offer an efficient means of curing the disease. The antiwolbachial property of tetracycline has been well worked out; however, treatment needs to be continued for a prolonged period of time to achieve complete elimination of Wolbachia from the filarial parasites and their subsequent killing. This results in acute toxicity, thus limiting its practical utility for clinical implementation. In order to increase efficacy of the antibiotic with minimal toxic manifestations, we developed liposomized formulation of the tetracycline. The liposomized tetracycline was found to be significantly more effective when compared to the free form of the drug. In contrast to the 90/120 days oral administration of the drug, the treatment schedule using the liposomized form of the drug was reduced to 12 alternate days with better efficacy of the treatment.

Topics: Administration, Oral; Animals; Anti-Bacterial Agents; Brugia malayi; Disease Models, Animal; Elephantiasis, Filarial; Female; Humans; Liposomes; Rats; Tetracycline; Wolbachia

Studies have shown that extracts of cementum from periodontally involved teeth stimulated cytokine secretion from cultured human monocytes and that this stimulatory effect is inhibited by conditioning of the cementum with tetracycline. Using the subcutaneous chamber model in mice, the present study was designed to test the ability of cementum extracts from periodontally diseased teeth to induce an inflammatory response in vivo and to evaluate the effect of cementum conditioning with tetracycline.. Subcutaneous chambers were implanted in 24 mice. Two weeks later, the animals received intrachamber injection of one of the following: diseased-cementum extract, healthy-cementum extract, diseased-cementum extract preconditioned with tetracycline, or medium alone. Chamber exudates were harvested and analyzed for leukocyte levels, tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, and interleukin-10 (IL-10).. Injection of healthy- or diseased-cementum extracts increased the intrachamber levels of leukocytes. Extracts of diseased cementum were found to significantly increase the levels of TNF-alpha, IFN-gamma, and IL-10, compared with extracts of healthy cementum or media alone. Peak cytokine levels were observed 2 hours postinjection. Conditioning of diseased cementum with tetracycline before extraction resulted in augmented levels of TNF-alpha and IFN-gamma, and reduced levels of IL-10, compared with untreated diseased cementum.. The present results demonstrate that conditioning of diseased cementum with tetracycline may induce an intense inflammatory response in a mouse model, and they suggest that local application of tetracycline for root conditioning should be carefully reinvestigated.

Topics: Analysis of Variance; Animals; Anti-Bacterial Agents; Cytokines; Dental Cementum; Diffusion Chambers, Culture; Disease Models, Animal; Humans; Interferon-gamma; Interleukin-10; Leukocyte Count; Mice; Periodontal Diseases; Tetracycline; Time Factors; Tumor Necrosis Factor-alpha

Inhibiting activity of the c-Myb transcription factor attenuates G1 to S phase cell cycle transitions in vascular smooth muscle cells (SMCs) in vitro. To determine the effects of arterial SMC-specific expression of a dominant-negative c-Myb molecule (Myb-Engrailed) on vascular remodeling in vivo, we performed carotid artery wire-denudation in 2 independent lines of binary transgenic mice with SM22alpha promoter-defined Doxycycline-suppressible expression of Myb-Engrailed. Adult mice with arterial SMC-specific expression of Myb-Engrailed were overtly normal in appearance and did not display any changes in cardiovascular structure or physiology. However, bromodeoxyuridine-defined arterial SMC proliferation, neointima formation, medial hyperplasia, and arterial remodeling were markedly decreased in mice expressing arterial SMC-restricted Myb-Engrailed after arterial injury. These data suggest that c-Myb activity in arterial SMCs is not essential for arterial structure or function during development, but is involved in the proliferation of arterial SMCs as occurs in vascular pathology, and that the expression of a dominant-negative c-Myb can dramatically reduce adverse arterial remodeling in an in vivo model of restenosis. As such, this model represents a novel tissue-specific strategy for the potential gene therapy of diseases characterized by arterial SMC proliferation.

Topics: Animals; Bromodeoxyuridine; Carotid Stenosis; Cell Division; Disease Models, Animal; Gene Expression; Genes, Dominant; Homeodomain Proteins; Mice; Mice, Transgenic; Microfilament Proteins; Muscle Proteins; Muscle, Smooth, Vascular; Promoter Regions, Genetic; Proto-Oncogene Proteins c-myb; Tetracycline; Transcription Factors; Tunica Intima

Based on the tetracycline-regulated gene expression system, a double-transgenic mouse model for liver fibrosis was established in which the expression of transforming growth factor beta1 (TGF-beta1) can be regulated deliberately by addition or removal of doxycycline hydrochloride to the drinking water. TGF-beta1 plasma levels in induced double-transgenic mice reached values ranging from 250 to 1,200 ng/mL, being 10 to 30 times above the normal plasma levels. By applying a cyclic induction-deinduction protocol, deleterious effects of the high plasma TGF-beta1 levels were overcome. By using this protocol, liver fibrosis occurred within a few cycles and progressed further to an intermediary fibrosis when cyclic induction was continued. On histochemical staining, a marked perisinusoidal deposition of extracellular matrix was detected accompanied by the activation of hepatic stellate cells as shown by alpha-smooth muscle actin (alpha-SMA) expression. Apoptosis of hepatocytes was prominent in TGF-beta1 high producers, leading to a decreasing number of TGF-beta1-expressing cells with time. No compensatory proliferation of hepatocytes could be detected. In advanced stages, fibrogenesis could be stopped by switching off TGF-beta1 production and reversal of fibrosis could be shown by (immuno)histochemistry within 6 to 21 days. Determination of messenger RNA (mRNA) levels of procollagen I and III, laminin (B1), matrix metalloproteinase (MMP)-2, -9, and -13, and tissue inhibitor of matrix metalloproteinase (TIMP)-1 and -2 by real-time reverse-transcription polymerase chain reaction (RT-PCR) provided insight into some mechanistic details of the fibrogenic process and its reversal. In conclusion, this model will enable the analysis of fibrogenesis at progressive stages and help in elucidating the cellular changes during development and regression of liver fibrosis caused by elevated TGF-beta1 expression.

Topics: Animals; Anti-Bacterial Agents; Disease Models, Animal; Extracellular Matrix Proteins; Gene Expression; Immunohistochemistry; Liver; Liver Cirrhosis; Mice; Mice, Transgenic; Tetracycline; Transforming Growth Factor beta; Transforming Growth Factor beta1

A conventional and easy method to establish a murine oral candidiasis model, which has not only a stable yeast population in the oral cavity but also symptoms characteristic of oral thrush, was developed by using a sedative agent. Mice were immunosuppressed with prednisolone and were given tetracycline hydrochloride. They were orally infected with 10(6) viable cells of Candida albicans by means of a cotton swab and enough chlorpromazine chloride had been injected to keep them in a sedative state about for 3 hr after inoculation. From day 3 to day 7 post inoculation, 10(5)-10(6) colony forming units of Candida were recovered from the oral cavity of each mouse and whitish, curd-like patches were observed on most parts of tongue. Microscopically, germ tubes had appeared on the tongue surface. This model would be a useful experimental oral candidiasis for investigating the pathogenesis of C. albicans oral infection and the efficacy of various antifungal agents microbiologically and symptomatically.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis, Oral; Chlorpromazine; Disease Models, Animal; Female; Fluconazole; Immunocompromised Host; Mice; Mice, Inbred ICR; Prednisolone; Tetracycline; Virulence

Neutrophil activation with concomitant matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) release has been implicated in the development of sepsis-induced acute lung injury. We hypothesized that COL-3, a chemically modified tetracycline known to inhibit MMP-2 and MMP-9, would reduce lung injury and improve survival in rats following cecal ligation and puncture (CLP).. Sprague-Dawley rats were separated into five groups: 1) sham CLP+ carboxymethylcellulose (CMC; vehicle for COL-3, n = 6); 2) sham CLP + COL-3 (n = 6); 3) CLP + CMC (n = 10); 4) CLP + single-dose (SD) COL-3 administered concomitant with CLP (n = 9); and 5) CLP + multiple-dose (MD) COL-3 administered concomitant with CLP and at 24 h after CLP (n = 15). Rats were sacrificed at 168 h (7 days) or immediately after death, with survival defined as hours after CLP. Histological lung assessment was made based on neutrophil infiltration, alveolar wall thickening, and intraalveolar edema fluid. Lung MMP-2 and MMP-9 levels were assessed by immunohistochemistry. MMP-2 and MMP-9 levels were correlated with survival by simple regression analysis.. The mortality of rats in the cecal ligation and puncture without treatment group (CLP + CMC) was 70% at 168 h. A single dose of COL-3 in the CLP + COL-3 (SD) group significantly reduced mortality to 54%. Furthermore, with a repeat dose of COL-3 at 24 h after CLP, mortality was significantly reduced to 33%. Pathologic lung changes seen histologically in the CLP + CMC group were significantly reduced by COL-3. A significant reduction in lung tissue levels of MMP-2 and MMP-9 was noted in both groups treated with COL-3. Reduction of MMP-2 and MMP-9 levels correlated with improved survival.. Inhibition of MMP-2 and MMP-9 by COL-3 in a clinically relevant model of sepsis-induced acute lung injury reduces pulmonary injury and improves survival in a dose-dependent fashion. Our results suggest that prophylactic treatment with COL-3 in high-risk patients may reduce the morbidity and mortality associated with sepsis-induced acute respiratory distress syndrome.

Topics: Animals; Cecum; Chromatography, High Pressure Liquid; Disease Models, Animal; Enzyme Inhibitors; Ligation; Lung; Lung Diseases; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Metalloendopeptidases; Punctures; Rats; Rats, Sprague-Dawley; Respiratory Distress Syndrome; Sepsis; Tetracycline; Tetracyclines

The BCR/ABL fusion protein is found in more than 90% of patients with chronic myeloid leukemia (CML) as well as in a subset of patients with acute B-cell leukemia. We have previously described a transgenic model for an inducible and reversible acute B-cell leukemia caused by p210 BCR/ABL. Here, we describe a new model of an inducible BCR/ABL disease by directing the expression of the oncogene to megakaryocytic progenitor cells within the murine bone marrow using the tetracycline-responsive expression system under the control of human CD34 regulatory elements. The predominant feature was the development of a chronic thrombocytosis. The condition progressed with the development of splenomegaly accompanied by lymphadenopathy in some mice. Affected animals demonstrated a dramatic increase in the number of megakaryocytes in the bone marrow and the spleen. Immunohistochemistry demonstrated that the reporter gene was expressed in hematopoietic stem cells (HSCs), common myeloid progenitor (CMP) cells, as well as in megakaryocytic/erythroid progenitor cells (MEPs). Although these mice did not display the increase in granulopoiesis commonly found in chronic myeloid leukemia (CML), the phenotype closely resembles a myeloproliferative disorder affecting the megakaryocytic lineage observed in some patients with the BCR/ABL P210 translocation.

Topics: Animals; Antigens, CD34; Disease Models, Animal; Fusion Proteins, bcr-abl; Gene Expression Regulation; Genes, Regulator; Genetic Vectors; Hematopoietic Stem Cells; Humans; Lymphatic Diseases; Megakaryocytes; Mice; Mice, Transgenic; Myeloproliferative Disorders; Splenomegaly; Tetracycline; Thrombocytosis

RNA interference (RNAi) is a powerful tool to induce loss-of-function phenotypes by inhibiting gene expression post-transcriptionally. Synthetic short interfering RNAs (siRNAs) as well as vector-based siRNA expression systems have been used successfully to silence gene expression in a variety of biological systems. We describe the development of an inducible siRNA expression system that is based on the tetracycline repressor and eukaryotic RNA polymerase III promoters (U6 and 7SK). For proof of concept we selectively inhibited expression of two catalytic subunits of the phosphatidylinositol 3-kinase (PI 3-kinase), p110alpha and p110beta, by using vector-derived short hairpin RNAs (shRNAs). Stable pools of human prostate cancer cells (PC-3) exhibiting reduced levels of both PI 3-kinase catalytic subunits due to the expression of corresponding shRNAs in an inducible fashion were established and analyzed for their invasive potential in vitro as well as in an orthotopic metastatic mouse model. This inducible system for RNAi allows an unbiased and comparable analysis of loss-of-function phenotypes by comparing selected isogenic cell populations on the induced and non-induced level. In addition, conditional RNAi allows the study of essential and multifunctional genes involved in complex biological processes by preventing inhibitory and compensatory effects caused by constitutive knockdown.

Topics: Animals; Catalytic Domain; Cell Line, Tumor; Disease Models, Animal; Gene Expression Regulation, Neoplastic; Humans; Male; Mice; Molecular Sequence Data; Nucleic Acid Conformation; Phosphatidylinositol 3-Kinases; Promoter Regions, Genetic; Prostatic Neoplasms; Protein Subunits; RNA Interference; RNA Polymerase III; RNA, Small Interfering; Tetracycline

Telogen effluvium is a common type of hair loss. Although the morphological changes associated with telogen effluvium have been well characterized, the underlying molecular mechanisms remain unknown, and no animal models have been developed. We report here that inducible transgenic mice expressing high levels of the transcription factor, tTA (tetracycline transactivator), plus a reporter luciferase gene, show a reversible hair loss phenotype. Skin of these mice exhibits an increase in the number of hair follicles at the telogen phase, but a decreased number of follicles at the anagen phase. These changes resemble skin pathology seen in patients with telogen effluvium, which suggests that the inducible transgenic mice may be useful as a model for this disorder. Moreover, since overexpression of several other transgenes failed to cause skin pathology, the present findings also indicate types of molecular abnormalities that may cause reversible hair loss.

Topics: Alopecia; Animals; Disease Models, Animal; Doxycycline; Gene Expression Regulation; Mice; Mice, Transgenic; Tetracycline; Trans-Activators

Prion diseases are transmissible neurodegenerative disorders of humans and animals for which no effective treatment is available. Conformationally altered, protease-resistant forms of the prion protein (PrP) termed PrP(Sc) are critical for disease transmissibility and pathogenesis, thus representing a primary target for therapeutic strategies. Based on previous findings that tetracyclines revert abnormal physicochemical properties and abolish neurotoxicity of PrP peptides in vitro, we tested the ability of these compounds to interact with PrP(Sc) from patients with the new variant of Creutzfeldt-Jakob disease (vCJD) and cattle with bovine spongiform encephalopathy (BSE). The incubation with tetracycline hydrochloride or doxycycline hyclate at concentrations ranging from 10 microM to 1 mM resulted in a dose-dependent decrease in protease resistance of PrP(Sc). This finding prompted us to investigate whether tetracyclines affect prion infectivity by using an animal model of disease. Syrian hamsters were injected intracerebrally with 263K scrapie-infected brain homogenate that was coincubated with 1 mM tetracycline hydrochloride, 1 mM doxycycline hyclate, or vehicle solution before inoculation. Hamsters injected with tetracycline-treated inoculum showed a significant delay in the onset of clinical signs of disease and prolonged survival time. These effects were paralleled by a delay in the appearance of magnetic-resonance abnormalities in the thalamus, neuropathological changes, and PrP(Sc) accumulation. When tetracycline was preincubated with highly diluted scrapie-infected inoculum, one third of hamsters did not develop disease. Our data suggest that these well characterized antibiotics reduce prion infectivity through a direct interaction with PrP(Sc) and are potentially useful for inactivation of BSE- or vCJD-contaminated products and prevention strategies.

Topics: Animals; Anti-Bacterial Agents; Brain; Cattle; Creutzfeldt-Jakob Syndrome; Cricetinae; Disease Models, Animal; Doxycycline; Encephalopathy, Bovine Spongiform; Endopeptidase K; Gentamicins; Guanidines; Humans; Isothiocyanates; Mesocricetus; Protein Denaturation; PrPSc Proteins; Scrapie; Tetracycline

Intrapleural loculation can increase morbidity in hemothoraces or parapneumonic effusions. Intrapleural fibrin precedes visceral-parietal pleural adhesions. We speculated that single-chain urokinase plasminogen activator alone or bound to its receptor could prevent these adhesions by their relative resistance to local inhibition by plasminogen activator inhibitors. We found that recombinant human single-chain urokinase-bound rabbit pleural mesothelial cells or lung fibroblasts with kinetics similar to that reported for human cells (kD of approximately 5 nM). The receptor-bound fibrinolysin maintained in vitro fibrinolytic activity in the presence of pleural fluids from rabbits with tetracycline-induced pleural injury over 24 hours. In rabbits given intrapleural single-chain urokinase 24 and 48 hours after intrapleural tetracycline (n = 10 animals), adhesions were prevented, whereas the receptor-complexed form (n = 12) attenuated adhesions versus vehicle/tetracycline-treated rabbits (n = 22, p

Topics: Animals; Anti-Bacterial Agents; Biomarkers; Body Fluids; Cell Count; Disease Models, Animal; Epithelium; Female; Fibrin; Fibroblasts; Pleura; Pleural Effusion; Pleurisy; Rabbits; Receptors, Cell Surface; Receptors, Urokinase Plasminogen Activator; Tetracycline; Tissue Adhesions; Urokinase-Type Plasminogen Activator

The ability to regulate gene expression constitutes a prerequisite for the development of gene therapy strategies aimed at the treatment of neurologic disorders. In the present work, we used tetracycline (Tet)-regulated lentiviral vectors to investigate the dose-dependent neuroprotective effect of human ciliary neurotrophic factor (CNTF) in the quinolinic acid (QA) model of Huntington's disease (HD). The Tet system was split in two lentiviruses, the first one containing the CNTF or green fluorescent protein (GFP) cDNAs under the control of the Tet-response element (TRE) and a second vector encoding the transactivator (tTA). Preliminary coinfection study demonstrated that 63.8% +/- 2.0% of infected cells contain at least two viral copies. Adult rats were then injected with CNTF- and GFP-expressing viral vectors followed 3 weeks later by an intrastriatal administration of QA. A significant reduction of apomorphine-induced rotations was observed in the CNTF-on group. In contrast, GFP-treated animals or CNTF-off rats displayed an ipsilateral turning behavior in response to apomorphine. A selective sparing of DARPP-32-, choline acetyltransferase (ChAT)-, and NADPH-d-positive neurons was observed in the striatum of CNTF-on rats compared to GFP animals and CNTF-off group. Enzyme-linked immunosorbent assay (ELISA) performed on striatal samples of rats sacrificed at the same time point indicated that this neuroprotective effect was associated with the production of 15.5 +/- 4.7 ng CNTF per milligram of protein whereas the residual CNTF expression in the off state (0.54 +/- 0.02 ng/mg of protein) was not sufficient to protect against QA toxicity. These results establish the proof of principle of neurotrophic factor dosing for neurodegenerative diseases and demonstrate the feasibility of lentiviral-mediated tetracycline-regulated gene transfer in the brain.

Topics: Animals; Brain; Choline O-Acetyltransferase; Ciliary Neurotrophic Factor; Disease Models, Animal; DNA, Complementary; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Female; Genetic Vectors; Green Fluorescent Proteins; Humans; Huntington Disease; Lentivirus; Luminescent Proteins; Neurons; Quinolinic Acid; Rats; Rats, Wistar; Recombinant Fusion Proteins; Tetracycline

The effect of calcium supplementation on the bone dynamics in the hard palate of the molar region (maxilla), mandible and proximal tibia in experimental osteoporotic rats was examined. Ninety ovariectomized (OVX) and 45 sham-OVX Wistar female rats were used in this study. All the rats received surgical operation at 6 weeks of age. Ovariectomized rats were fed on a low calcium diet (0.02%) for 12 weeks post-operation, and then randomly divided into the two following groups. One group was fed on high calcium diet (2.30%) (OVX-HCa) and the other group was remained on the low calcium diet (OVX-LCa). Sham-OVX rats were fed on regular calcium diet (1.15%) during the experimental period (Sham-OVX). Histomorphological analysis was carried out from 12 to 32 weeks post-operation. On undecalcified thin section, bone volume, eroded surface, osteoid surface and bone formation rate were calculated for cortical bone of the maxilla, and for cancellous bone of the mandible and proximal tibia. In the OVX-LCa group, compared with the Sham-OVX group, decrease of the bone volume and increase of the bone resorption and formation parameters were detected throughout the observation periods. In the OVX-HCa group, compared with the OVX-LCa group, increase of the bone volume and temporarily increased parameters of bone formation at 1 week after feeding on high calcium diet were observed in the maxilla, but these changes were not observed in the mandible and proximal tibia. Moreover, the bone resorption and formation parameters in the maxilla, mandible and proximal tibia in the OVX-HCa group became equivalent to the Sham-OVX levels with the passage of time.

Topics: Analysis of Variance; Animals; Body Weight; Bone Matrix; Bone Resorption; Calcium, Dietary; Dietary Supplements; Disease Models, Animal; Female; Fluoresceins; Fluorescent Dyes; Image Processing, Computer-Assisted; Mandible; Maxilla; Osteogenesis; Osteoporosis; Ovariectomy; Palate, Hard; Random Allocation; Rats; Rats, Wistar; Statistics as Topic; Tetracycline; Tibia

We evaluated the effect of optimized doses and dosing schedules of metronidazole, tetracycline, and bismuth-metronidazole-tetracycline (BMT) triple therapy with only 1 day of dosing on Helicobacter pylori SS1 titers in a mouse model. A reduction of bacterial titers was observable with 22.5 and 112.5 mg of metronidazole per kg of body weight (as well as BMT) given twice daily and four times daily (QID). Two hundred milligrams of tetracycline per kilogram, given QID, resulted in only a slight reduction of H. pylori titers in the stomach. We argue that optimization of doses based on antimicrobial drug levels in the animal and shortened (1 or 2 days) drug administration can be used to facilitate early evaluation of putative anti-H. pylori drug candidates in lieu of using human doses and extended schedules (7 to 14 days), as can be deduced from the results seen with these antimicrobial agents.

Topics: Animals; Bismuth; Disease Models, Animal; Drug Therapy, Combination; Female; Helicobacter Infections; Helicobacter pylori; Humans; Metronidazole; Mice; Mice, Inbred C57BL; Organometallic Compounds; Salicylates; Tetracycline

An association between postmenopausal osteoporosis and tooth loss has been proposed. However, histomorphometrical changes in alveolar bone following estrogen deficiency are rarely reported with data on microtrabecular structural changes. To clarify the relationship between estrogen deficiency and tooth loss, we histomorphometrically analyzed the trabecular structural changes of mandibular alveolar bone in ovariectomized rats. Twenty-four adult female Fischer rats were used. Eight rats were sacrificed on day 0 (baseline). The remaining 16 rats were divided into two groups. One group was ovariectomized bilaterally (OVX) and the other group was subjected to sham surgery (Sham). After administration of tetracycline and calcein, the animals were sacrificed 60 days after surgery. Bone histomorphometry, node-strut analysis and measurement of thickness of alveolar bone proper were performed on the interradicular septum of the first molar on the sagittal surface. The trabecular bone volume and trabecular number of the OVX group were significantly lower than those of the baseline and Sham groups. All of the bone resorptive and formative parameters of the OVX group were significantly higher (about one-and-a-half times) than those of the Sham group. Several osteoclasts were seen lining the irregular, eroded surface facing the bone marrow in the OVX group. Furthermore, the OVX group tended to have low microtrabecular stiffness and showed significantly thinner distal alveolar bone proper than in the baseline and Sham groups. In summary, estrogen deficiency caused osteoporotic changes and thin alveolar bone proper in the interradicular septum of rat first molar. This phenomenon might accelerate destruction of alveolar bone and tooth loss, especially in elderly women affected by periodontal disease.

Topics: Alveolar Process; Analysis of Variance; Animals; Bone Density; Bone Marrow; Bone Remodeling; Bone Resorption; Disease Models, Animal; Estrogens; Female; Fluoresceins; Fluorescent Dyes; Mandible; Microscopy, Confocal; Molar; Osteoclasts; Osteoporosis; Ovariectomy; Ovary; Rats; Rats, Inbred F344; Statistics as Topic; Tetracycline

Topics: Animals; Antibiotic Prophylaxis; Bacterial Translocation; Colony-Forming Units Assay; Disease Models, Animal; Female; Rats; Rats, Wistar; Sepsis; Tetracycline

Charcot-Marie-Tooth disease type 1A, a hereditary demyelinating neuropathy, is usually caused by overexpression of peripheral myelin protein 22 (PMP22) due to a genomic duplication. We have generated a transgenic mouse model in which mouse pmp22 overexpression can be regulated. In this mouse model, overexpression of pmp22 occurs specifically in Schwann cells of the peripheral nerve and is switched off when the mice are fed tetracycline. Overexpression of pmp22 throughout life (in the absence of tetracycline) causes demyelination. In contrast, myelination is nearly normal when pmp22 overexpression is switched off throughout life by feeding the mice tetracycline. When overexpression of pmp22 is switched off in adult mice, correction begins within 1 week and myelination is well advanced by 3 months (although the myelin sheaths are still thinner than normal), indicating that the Schwann cells are poised to start myelination. Upregulation of the gene in adult mice (which had previously had normal pmp22 expression) is followed by active demyelination within 1 week, which had plateaued by 8 weeks. This indicates that Schwann cells with mature myelin are sensitive to increased amounts of pmp22 such that they rapidly demyelinate. Thus, demyelination can largely be corrected within a few months, but the correction will be sensitive to subsequent upregulation of pmp22.

Topics: Animals; Charcot-Marie-Tooth Disease; Demyelinating Diseases; Disease Models, Animal; Gene Expression Regulation; Humans; Mice; Mice, Transgenic; Myelin Proteins; Myelin Sheath; Neural Conduction; Phenotype; Regulatory Sequences, Nucleic Acid; RNA, Messenger; Schwann Cells; Tetracycline; Tetracycline Resistance

Genetic evidence indicates that several mutations in tau, including G272V, are linked to frontotemporal dementia with parkinsonism. We expressed this mutation in mouse brains by combining a prion protein promoter-driven expression system with an autoregulatory transactivator loop that resulted in high expression of human G272V tau in neurons and in oligodendrocytes. We show that G272V tau can form filaments in murine oligodendrocytes. Electron microscopy established that the filaments were either straight or had a twisted structure; these were 17-20 nm wide and had a periodicity of approximately 75 nm. Filament formation was associated with tau phosphorylation at distinct sites, including the AT8 epitope 202/205 in vivo. Immunogold electron microscopy of sarcosyl-extracted spinal cords from G272V transgenic mice using phosphorylation-dependent antibodies AT8 or AT100 identified several sparsely gold-labelled 6-nm filaments. In the spinal cord, fibrillary inclusions were also identified by thioflavin-S fluorescent microscopy in oligodendrocytes and motor neurons. These results establish that expression of the G272V mutation in mice causes oligodendroglial fibrillary lesions that are similar to those seen in human tauopathies.

Topics: Animals; Central Nervous System; Cytoskeleton; Disease Models, Animal; Immunohistochemistry; Mice; Mice, Transgenic; Microscopy, Electron; Mutation; Nerve Degeneration; Neurodegenerative Diseases; Neurofibrillary Tangles; Neurons; Oligodendroglia; Phosphorylation; Solubility; tau Proteins; Tetracycline; Trans-Activators

The recA gene in Porphyromonas gingivalis is involved in DNA repair. To further elucidate the importance of the recA locus in the pathogenesis of P. gingivalis, we assessed its ability for expression in an animal host. The promoterless xa-tetA(Q)2 cassette was used in heterodiploid mutants to study recA promoter activity during infection. P. gingivalis FLL118.1 had the xa-tetA(Q)2 cassette under the control of recA promoter whereas P. gingivalis FLL119 had the cassette in the opposite orientation. xa encodes a bifunctional xylosidase/arabinosidase enzyme (XA) and the tetA(Q)2 gene product confers tetracycline resistance. Intramuscular infection in a mouse model allowed the recovery of the bacteria from inguinal lymph nodes. Infusion of tetracycline in the animals permitted the enrichment P. gingivalis FLL118.1 over the wild-type strain, during a mixed infection. The xylosidase activity of FLL118.1 could be detected on agar plates in the presence of 5-methylumbellifiry-beta-D-xyloside. No such enrichment for xylosidase activity was detected when the mixture of P. gingivalis W83 and P. gingivalis FLL119 was used to infect the mouse or cultured in vitro. These results indicated that recA promoter was transcriptionally active during the infection of the murine host and further support the importance of this locus during the P. gingivalis infection process.

Topics: Animals; Anti-Bacterial Agents; Antiporters; Bacterial Proteins; Bacteroidaceae Infections; Chromosome Mapping; Diploidy; Disease Models, Animal; DNA Repair; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Enzymologic; Glycoside Hydrolases; Lymph Nodes; Mice; Mice, Inbred BALB C; Mutation; Phenotype; Polymerase Chain Reaction; Porphyromonas gingivalis; Promoter Regions, Genetic; Rec A Recombinases; Tetracycline; Tetracycline Resistance; Transcription, Genetic; Virulence; Xylosidases

We established a straightforward murine model of oropharyngeal candidiasis. Mice were immunosuppressed with cortisone acetate, anesthetized, and then inoculated by placing cotton wool balls saturated with Candida albicans sublingually for 2 h. A prolonged, reproducible infection was induced. This model may be useful for antifungal screening or pathogenesis studies.

Topics: Animals; Anti-Bacterial Agents; Candidiasis, Oral; Cell Count; Cortisone; Disease Models, Animal; Esophagus; Immunosuppressive Agents; Male; Mice; Pharyngeal Diseases; Tetracycline; Tongue

Neuronal intranuclear inclusions are a histopathological hallmark of Huntington's disease. Nevertheless, the precise mechanism by which they are formed and their relevance to neuronal cell death and/or dysfunction remains unclear. We recently generated a conditional mouse model of Huntington's disease (HD94) in which silencing expression of mutated huntingtin led to the disappearance of intranuclear aggregates and amelioration of the behavioral phenotype. Here, we analyze primary striatal neuronal cultures from HD94 mice to explore the dynamics of aggregate formation and reversal, the possible mechanisms involved, and the correlation between aggregates and neuronal death. In parallel, we examine symptomatic adult HD94 mice in similar studies and explored the relationship between aggregate clearance and behavioral reversal. We report that, in culture, aggregate formation and reversal were rapid processes, such that 2 d of transgene expression led to aggregate formation, and 5 d of transgene suppression led to aggregate disappearance. In mice, full reversal of aggregates and intranuclear mutant huntingtin was more rapid than reported previously and preceded the motor recovery by several weeks. Furthermore, the proteasome inhibitor lactacystin inhibited the aggregate clearance observed in culture, thus indicating that aggregate formation is a balance between the rate of huntingtin synthesis and its degradation by the proteasome. Finally, neither expression of the mutant huntingtin nor aggregates compromised the viability of HD94 cultures. This correlated with the lack of cell death in symptomatic HD94 mice, thus demonstrating that neuronal dysfunction, and not cell loss, triggered by mutant huntingtin underlies symptomatology.

Topics: Acetylcysteine; Animals; Behavior, Animal; Cell Death; Cell Survival; Cells, Cultured; Corpus Striatum; Cysteine Endopeptidases; Disease Models, Animal; Gene Silencing; Genes, Dominant; Huntingtin Protein; Huntington Disease; Locomotion; Macromolecular Substances; Mice; Mice, Neurologic Mutants; Multienzyme Complexes; Nerve Tissue Proteins; Neurons; Nuclear Proteins; Phenotype; Proteasome Endopeptidase Complex; Remission Induction; Tetracycline; Transgenes; Ubiquitin

Noninflammatory structural alterations, variously referred to as airway remodeling, are well documented in the asthmatic airway. However, the pathogenesis of these alterations, the importance of airway remodeling in generating the asthma phenotype, and the natural history of airway remodeling responses have not been adequately defined. Because exaggerated cytokine production is a characteristic feature of the asthmatic airway, we used constitutive and inducible overexpression transgenic systems to investigate the contributions that interleukin 11 (IL-11) and IL-13 might make to airway remodeling responses. These studies demonstrated that both cytokines produce responses in the murine airway with features similar to those in human asthmatic tissues. IL-11 caused airway fibrosis with the enhanced accumulation of interstitial collagens, myocytes, and myofibroblasts. IL-13 caused mucous metaplasia, enhanced mucin gene expression, enhanced tissue hyaluronic acid accumulation, and subepithelial fibrosis. Importantly, IL-11 was detected most readily in tissues from asthmatic subjects with severe airway remodeling that was similar to that seen in the IL-11 transgenic mice. In addition, IL-11 was shown to inhibit asthma-like inflammation while stimulating airway fibrosis. This suggests that IL-11 elaboration is, in part, an attempt at airway healing. Last, a novel triple transgenic system is described that allows transgene expression to be regulated in a true "on/off" manner. This system may be useful in defining the reversibility of transgene-induced airway remodeling responses.

Topics: Animals; Anti-Bacterial Agents; Asthma; Chronic Disease; Disease Models, Animal; Gene Expression; Humans; Inflammation; Interleukin-11; Interleukin-13; Lung; Mice; Mice, Transgenic; Phenotype; RNA, Messenger; Tetracycline; Transcription, Genetic

The effects of orchidectomy on bone metabolism in male beagle dogs were examined using twelve 2-year-old dogs that were orchidectomized. The dogs' bilateral iliac bones, double-labeled with tetracycline and calcein for the histomorphometry, were obtained from three dogs prior to orchidectomy and at 3, 6, 9, and 12 months afterwards. The serum biochemical constituents related to bone metabolism were examined before and every month after orchidectomy. Between 1 and 6 months after orchidectomy, the value of serum testosterone decreased (1 month), while the levels of parathyroid hormone, calcitonin, total calcium, osteocalcin, and alkaline phosphatase activity increased significantly, indicating a high bone turnover. The mean trabecular thickness and the fraction of labeled osteoid surface decreased significantly 3 months after orchidectomy, but other histomorphometric parameters were unchanged. In the period 7-12 months after orchidectomy, the parathyroid hormone level increased ever and above that of the first 6-month period, while the levels of calcitonin, osteocalcin, alkaline phosphatase activity, and phosphorus decreased. The bone volume, mean trabecular thickness, and the fraction of labeled trabecular surface decreased significantly compared with the pre-orchidectomy values. These findings indicate an imbalance in bone metabolism (i.e. bone resorption > bone formation). These results indicate that a loss of bone volume accompanied the fall in sex hormone levels following orchidectomy and suggest that the orchidectomized dog is available as an animal model for studying osteoporosis caused by hypogonadism and the decline of sex functions in men.

Topics: Alkaline Phosphatase; Animals; Biopsy; Body Weight; Bone and Bones; Bone Remodeling; Calcitonin; Calcium; Disease Models, Animal; Dogs; Fluoresceins; Fluorescent Dyes; Ilium; Image Processing, Computer-Assisted; Male; Microscopy, Fluorescence; Orchiectomy; Osteocalcin; Parathyroid Hormone; Phosphorus; Protein Synthesis Inhibitors; Testosterone; Tetracycline

In order to identify the alternative effective chemotherapeutic agents for murine babesiosis, some selected drugs were examined for their efficacy against protozoan infection in the mouse-Babesia rodhaini (B. rodhaini) model. Clindamycin was not completely effective for elimination of parasites in a dose of 50 mg or 100 mg/kg BW/day b.i.d. but effective to prolong the life span of hosts, while it completely cured B. rodhaini infections in a dose of 200 mg. On the other hand, a double therapy consisting of 2 treatments with 100 mg clindamycin and 100 mg clindamycin and with 100 mg clindamycin and 100 mg tetracycline; respectively, and a single therapy with 100 mg tetracycline or 200 mg clindamycin, had a possibility to clear away B. rodhaini organisms from hosts. However, almost all the treatment groups, had a relapse of the infection within 10 days post treatment or re-treatment. Cured mice by treatment with clindamycin and clindamycin, or clindamycin and tetracycline showed complete resistance against challenge with B. rodhaini, while mice cured by administration of clindamycin at 200 mg or tetracycline at 100 mg showed incomplete resistance to challenge infection. The present data suggest that the two former chemotherapies can induce effective protective immunity (premunization), but the latter two chemotherapies induce incomplete premunization.

Topics: Animals; Anti-Bacterial Agents; Antiprotozoal Agents; Babesia; Babesiosis; Clindamycin; Disease Models, Animal; Drug Administration Schedule; Male; Mice; Recurrence; Rodent Diseases; Tetracycline

The MIC90 of glycylcycline (< or =0.06 mg/L) against 55 strains of Streptococcus pneumoniae was 100-fold lower than that of minocycline or tetracycline. In a mouse model of penicillin-resistant S. pneumoniae (PRSP) pneumonia, glycylcycline (10 mg/kg) decreased bacterial counts in the lungs from 10(6) cfu to <10(2) cfu, whereas no apparent reduction of bacterial numbers was observed with minocycline or penicillin G. Pharmacokinetic studies showed that the half-life and area under the curve of glycylcycline were superior to those of minocycline and penicillin G in the lungs. These results show a preferential distribution of glycylcycline in the lungs and potent in vivo bactericidal activity in PRSP pneumonia.

Topics: Animals; Anti-Bacterial Agents; Disease Models, Animal; Female; Lung; Mice; Mice, Inbred CBA; Microbial Sensitivity Tests; Minocycline; Penicillin G; Penicillins; Pneumonia, Pneumococcal; Streptococcus pneumoniae; Tetracycline

The ability of nine clinical isolates of Candida species (three C. albicans, three C. tropicalis and three C. parapsilosis) to colonize and invade the gastrointestinal (GI) tract of adult male CD-1 (ICR) mice was determined. The effect of dietary tetracycline plus glucose supplementation on colonization was evaluated. Strains were intragastrically inoculated. Tetracycline and glucose altered substantially aerobic flora, especially streptococci (average fall 1.1 +/-0.3 log(10) CFU/g, p<0.01 by the Student's t test). At two weeks after oral challenge, sustained and high colonization of GI tract by Candida (mean 5,28 +/- 0.18 log(10) CFU/g, p<0.01) was achieved in all mice receiving glucose-tetracycline supplementation, excepting in animals inoculated with one of C. tropicalis isolates. Histologic sections of the stomachs revealed multiple intraepithelial micro-abscesses associated with hyphae in the region of the cardial-atrium fold. Under immunosuppression, systemic spread of C. albicans and C. tropicalis was observed in 62% and 24% of animals receiving dietary supplementation respectively. Dissemination was not noted for C. parapsilosis isolates. We have developed a simple and inexpensive murine model of sustained colonization of GI tract. This model could be useful for analyzing prophylaxis, treatment and diagnosis of systemic Candida infections and for evaluating virulence of strains.

Topics: Animals; Anti-Bacterial Agents; Candida albicans; Candidiasis; Cyclophosphamide; Digestive System; Disease Models, Animal; Esophagus; Feces; Gastric Mucosa; Glucose; Histocytochemistry; Image Processing, Computer-Assisted; Immunosuppressive Agents; Liver; Male; Methylprednisolone; Mice; Mice, Inbred ICR; Specific Pathogen-Free Organisms; Tetracycline

The twy (tiptoe-walking-Yoshimura) mouse, established in Japan in 1978 by brother-sister mating of ICR strain mice, is a valuable mutant as a model of ossification of the posterior longitudinal ligament (OPLL). OPLL causes severe myelopathy and has been thought to be very similar to ankylosing spinal hyperostosis (ASH) and diffuse idiopathic skeletal hyperostosis (DISH). In the twy mouse, both an increase in vertebral cortical membranous bone formation and a decrease in trabecular bone mass due to accelerated bone resorption occur simultaneously. This process is attributed to an inherited autosomal recessive single gene (twy). Calcitonin's suppression of bone resorption has been well established in the past, whereas the effects of this hormone on bone formation remain to be defined. Of particular interest is the simultaneous action of calcitonin on the abnormally accelerated bone formation and resorption. Thirty twy mice and 14 ICR mice were divided into seven groups, and changes induced by calcitonin on vertebral cortical appositional rate and on trabecular bone mass were investigated histomorphometrically. Results were (1) osteoclastic activity on trabecular surface was clearly suppressed by chicken calcitonin injected subcutaneously for 4 weeks; (2) no significant difference between the lumbar vertebral periosteal bone formation of calcitonin (CA) and vehicle-administrated twy mice groups. However, on the periosteal surface of the cervical vertebrae of the 6-week-old twy mice, the abnormally accelerated bone formation was suppressed by CA administration. This was also true for the elderly twy mice, although the effect was less pronounced. In conclusion, CA suppressed the abnormally hyperactivated periosteal bone formation. Results also suggested a possible therapeutic value of CA for OPLL.

Topics: Animals; Bone Diseases, Metabolic; Bone Remodeling; Calcitonin; Cervical Vertebrae; Disease Models, Animal; Female; Fluoresceins; Fluorescent Dyes; Hyperostosis, Diffuse Idiopathic Skeletal; Lumbar Vertebrae; Male; Mice; Mice, Inbred ICR; Mice, Mutant Strains; Ossification of Posterior Longitudinal Ligament; Periosteum; Radiography; Tetracycline

Numerous studies have demonstrated bone loss in rats following immobilization by tenotomy or nerve sectioning and following ovariectomy. However, few experiments have focused on bone change in rats with arthritis. We investigated bone loss in the proximal tibia and lumbar vertebra in rats with type II collagen-induced arthritis, an experimental model of rheumatoid arthritis, using histomorphometry. Bone loss in the early phase after immunization reflected a significant increase in numbers of osteoclasts and temporarily decreased bone formation. In the proximal tibia, near an arthritic joint, osteoclast numbers associated with bone trabeculae were increased four times over control numbers 4 weeks after immunization. In the lumbar vertebra, where arthritis was not shown, recruitment of osteoclasts occurred later than in the proximal tibia. With time, in both the proximal tibia and lumbar vertebra bone resorption normalized, but bone formation rate and double-label surface by tetracycline, a parameter reflecting bone formation, were increased above control values. We conclude that differences between the proximal tibia and lumbar vertebra probably reflected resumption of function as well as distance from areas of inflammation. These findings indicate that collagen-induced arthritis in rats is a useful model not only of autoimmunity, but also of juxta-articular and generalized osteoporosis in rheumatoid arthritis.

Topics: Animals; Arthritis, Experimental; Biomarkers; Body Weight; Bone Diseases, Metabolic; Bone Resorption; Cell Count; Collagen; Disease Models, Animal; Female; Immobilization; Knee Joint; Lumbar Vertebrae; Osteoclasts; Radiography; Rats; Rats, Sprague-Dawley; Tetracycline; Tibia

Sclerosants such as tetracycline (TCN) have often been used in the control of malignant pleural effusions. Although the resultant inflammatory response is probably important in the ensuing pleural fibrosis, the signals responsible for the cellular influx into the pleural space following TCN instillation are not well understood. This study, therefore, sought to determine whether the chemokines interleukin-8 (IL-8), growth-related protein (Gro), and monocyte chemotactic protein-1 (MCP-1) were locally elaborated within the first 72 h following intrapleural TCN administration. TCN induced an exudative effusion with high lactate dehydrogenase activity. Although there was no significant change in the pleural fluid total leukocyte content, the median polymorphonuclear neutrophil concentration decreased from 1.067x10(6) to 2.03x10(5) cells x mL(-1) between 24 and 72 h, whereas the median macrophage concentration increased from 1.44x10(5) to 5.98x10(5) cells x mL(-1) over the same period. Furthermore, IL-8, Gro and MCP-1 concentrations decreased between 24 and 72 h. Immunocytochemistry indicated expression of IL-8 by pleural mesothelial cells 24 h, but not 72 h, following TCN administration. The data suggest that local elaboration of interleukin-8 and growth-related protein, in part of mesothelial origin, may influence neutrophil recruitment in tetracycline-induced pleuritis.

Topics: Analysis of Variance; Animals; Chemokine CCL2; Chemokines; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Female; Immunohistochemistry; Interleukin-8; Leukocyte Count; Neutrophils; Nuclear Proteins; Pleural Effusion; Pleurisy; Rabbits; Statistics, Nonparametric; Tetracycline

This study was performed to evaluate the enzyme production in response to implantation of the hydrogel material used in the experimental Chirila keratoprosthesis (KPro) and to assess the effects of five topical drugs on enzyme production and activity. KPros may be extruded from the cornea as a result of tissue melting, a process that involves excessive enzyme activity. To reduce the possibility of implant loss for the hydrogel Chirila KPro, a number of antiinflammatory drugs that have been used to treat other corneal melting conditions were investigated for their effect on initial collagenase activity after the implantation of KPro material into the rabbit cornea.. Poly(2-hydroxyethyl methacrylate) sponge pieces were implanted into rabbit corneas. Prednisolone, tetracycline, medroxyprogesterone, acetylcysteine, and sodium citrate were assessed for effects on gelatinolytic activity and stromal collagenase [matrix metalloprotease-1 (MMP-1)] production in vivo and in vitro by using zymography and Western blotting techniques.. Whereas all five anticollagenase drugs were effective in reducing gelatinolytic activity in vitro, many were ineffective in vivo. However, medroxyprogesterone caused a reduction of gelatinolytic activity in vivo. The amount of MMP-1, as measured by immunoblotting, also was reduced by medroxyprogesterone treatment when compared with untreated controls. An increase in the apparent molecular weight of MMP-1 in operated corneas appears to be the result of the association of MMP-1 with collagen fragments resulting from the surgical trauma.. This study indicates that topical medroxyprogesterone may be a useful adjunctive therapy after prosthokeratoplasty.

Topics: Acetylcysteine; Administration, Topical; Animals; Blotting, Western; Citrates; Collagenases; Cornea; Disease Models, Animal; Electrophoresis, Polyacrylamide Gel; Gelatinases; Graft Survival; Implants, Experimental; Matrix Metalloproteinase Inhibitors; Medroxyprogesterone; Methacrylates; Ophthalmic Solutions; Prednisolone; Rabbits; Sodium Citrate; Tetracycline; Treatment Outcome

Tissue remodeling is a dynamic state in which a balance is achieved between the proteolytic breakdown and synthesis of the extracellular matrix. Type I collagen is a major component of the gingival connective tissue (GCT) and the periodontal ligament (PDL) throughout development, while type XII collagen has been found in the mature forms of these tissues. The purpose of this study was to investigate the effects of periodontitis on the expression of type I and XII collagen and subsequently to investigate the effects of doxycycline (DOXY) and chemically modified non-antimicrobial tetracycline (CMT-1) on the expression of these molecules in this model. Adult barrier-raised male Sprague-Dawley rats were inoculated with Porphyromonas gingivalis obtained from humans to create the experimental periodontitis. The animals with the P. gingivalis-induced periodontitis were then split into the following groups: Group A served as infected untreated controls (PGI group); group B was treated with doxycycline (DOXY group); and group C was treated with chemically modified tetracycline-1 (CMT-1 group). Group D contained uninfected animals that served as uninfected controls (NIC group). The expression of type I and XII collagen mRNAs was examined by in situ hybridization in each group, with the co-expression of these molecules representing mature and functional gingival connective tissue. In the NIC group, cells hybridized with digoxygenine-labeled cDNA probes encoding rat alpha2(I) or alpha1(XII) collagens were found distributed uniformly throughout the periodontal connective tissue. The PGI group showed little hybridization in the areas of infection, while both the DOXY and CMT-1 groups showed co-expression of the alpha2(I) and alpha1(XII) probes in the GCT and coronal part of the PDL. This study demonstrates that doxycycline and CMT-1 moderate or reduce the inhibitory effects of periodontal infection on the expression of type I and type XII collagen mRNAs. These results suggest that doxycycline and a form of non-antimicrobial tetracycline, chemically modified tetracycline-1, can reduce periodontal destruction by reversing the inhibitory effect of periodontal infection on collagen synthesis.

Topics: Affinity Labels; Animals; Anti-Bacterial Agents; Bacteroidaceae Infections; Collagen; Connective Tissue; Digoxigenin; Disease Models, Animal; DNA Probes; DNA, Complementary; Doxycycline; Extracellular Matrix; Gene Expression Regulation; Gingiva; In Situ Hybridization; Male; Matrix Metalloproteinase Inhibitors; Periodontal Ligament; Periodontitis; Porphyromonas gingivalis; Protease Inhibitors; Rats; Rats, Sprague-Dawley; RNA, Messenger; Tetracycline

Topics: Animals; Anti-Bacterial Agents; Clinical Trials as Topic; Disease Models, Animal; Doxycycline; Erythromycin; Humans; Legionnaires' Disease; Tetracycline

Cell loss contributes to the pathogenesis of many inherited and acquired human diseases. We have developed a system to conditionally ablate cells of any lineage and developmental stage in the mouse by regulated expression of the diphtheria toxin A (DTA) gene by using tetracycline-responsive promoters. As an example of this approach, we targeted expression of DTA to the hearts of adult mice to model structural abnormalities commonly observed in human cardiomyopathies. Induction of DTA expression resulted in cell loss, fibrosis, and chamber dilatation. As in many human cardiomyopathies, transgenic mice developed spontaneous arrhythmias in vivo, and programmed electrical stimulation of isolated-perfused transgenic hearts demonstrated a strikingly high incidence of spontaneous and inducible ventricular tachycardia. Affected mice showed marked perturbations of cardiac gap junction channel expression and localization, including a subset with disorganized epicardial activation patterns as revealed by optical action potential mapping. These studies provide important insights into mechanisms of arrhythmogenesis and suggest that conditional lineage ablation may have wide applicability for studies of disease pathogenesis.

Topics: Action Potentials; Animals; Cardiomyopathies; Connexins; Diphtheria Toxin; Disease; Disease Models, Animal; Fluorescent Antibody Technique; Gap Junction alpha-5 Protein; Gene Targeting; Heart; Histocytochemistry; Humans; Mice; Mice, Transgenic; Myocardium; Promoter Regions, Genetic; Tachycardia, Ventricular; Tetracycline

The RB/p105 and p107 genes of the retinoblastoma family are tumor suppressor genes whose proteins are inactivated by interaction with T-antigen proteins encoded by polyomaviruses (e.g., simian virus 40 and human JC virus), which have been found to be highly tumorigenic in animals. A variety of indirect evidence suggests that another member of the retinoblastoma gene family, RB2/p130, is also a tumor suppressor gene. To investigate the putative tumor suppressor activity of RB2/p130 more directly, we utilized a tetracycline-regulated gene expression system to control expression of the encoded protein pRb2/p130 in JC virus-induced hamster brain tumor cells and to study the effects of pRb2/p130 on the growth of such tumor cells in nude mice. The ability of pRb2/p130 to interact with JC virus T antigen was also studied.. Northern blot hybridization analyses were performed on samples of total cellular RNA to measure RB2/p130 and beta-actin messenger RNA levels. Immunoprecipitation and western blot analyses were used to determine T-antigen and pRb2/p130 protein levels and to assess the phosphorylation status of these proteins. Tumor cells were injected subcutaneously into nude mice, and tumor growth, with or without induced expression of pRb2/p130, was monitored.. Induction of pRb2/p130 expression brought about a 3.2-fold, or 69% (95% confidence interval = 64%-73%), reduction in final tumor mass in nude mice. We also demonstrated that JC virus T antigen binds hypophosphorylated pRb2/p130 and that stimulation of pRb2/p130 expression overcomes cellular transformation mediated by this antigen.. Our findings support the hypothesis that RB2/p130 is a tumor suppressor gene.

Topics: Animals; Antigens, Viral, Tumor; Blotting, Northern; Blotting, Western; Brain Neoplasms; Cricetinae; Disease Models, Animal; DNA, Neoplasm; Flow Cytometry; Gene Expression Regulation, Neoplastic; Gene Expression Regulation, Viral; Genes, Retinoblastoma; Genes, Tumor Suppressor; Humans; JC Virus; Mice; Mice, Nude; Phosphoproteins; Precipitin Tests; Protein Synthesis Inhibitors; Proteins; Retinoblastoma-Like Protein p130; Tetracycline; Tumor Cells, Cultured; Tumor Stem Cell Assay

The basic mechanisms underlying reactive arthritis and specifically the joint injury that follows intra-articular Chlamydia trachomatis infection have not been defined. The present study addresses this question through the development of an experimental model. Stable cell lines were generated from synoviocytes harvested from the knee joints of Lewis rats. The synoviocytes were cocultivated with C. trachomatis to allow invasion by the microbe and were then transferred by intra-articular injection into the knee joints of Lewis rats. The ensuing arthritis could be subdivided into an early phase (

Topics: Animals; Arthritis, Reactive; Bacterial Outer Membrane Proteins; Blotting, Western; Chlamydia Infections; Chlamydia trachomatis; Chronic Disease; Ciprofloxacin; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Female; Injections, Intra-Articular; Injections, Intramuscular; Injections, Subcutaneous; Lipopolysaccharides; Male; Microscopy, Fluorescence; Rats; Rats, Inbred Lew; Spleen; Synovial Membrane; Tetracycline; Time Factors

We have used an experimental model employing the bent tail of rats to investigate the effects of mechanical forces on bones and joints. Mechanical strain could be applied to the bones and joints of the tail without direct surgical exposure or the application of pins and wires. The intervertebral disc showed stretched annular lamellae on the convex side, while the annulus fibrosus on the concave side was pinched between the inner corners of the vertebral epiphysis. In young rats with an active growth plate, a transverse fissure appeared at the level of the hypertrophic cell layer or the primary metaphyseal trabecular zone. Metaphyseal and epiphyseal trabeculae on the compressed side were thicker and more dense than those of the distracted part of the vertebra. In growing animals, morphometric analysis of hemiepiphyseal and hemimetaphyseal areas, and the corresponding trabecular bone density, showed significant differences between the compressed and distracted sides. No differences were observed in adult rats. We found no significant differences in osteoclast number between compressed and distracted sides in either age group. Our results provide quantitative evidence of the working of 'Wolff's law'. The differences in trabecular density are examples of remodelling by osteoclasts and osteoblasts; our finding of no significant difference in osteoclast numbers between the hemiepiphyses in the experimental and control groups suggests that the response of living bone to altered strain is mediated by osteoblasts.

Topics: Age Factors; Animals; Bone and Bones; Bone Density; Bone Marrow; Bone Remodeling; Calcification, Physiologic; Cell Count; Disease Models, Animal; Epiphyses; Fluorescent Dyes; Growth Plate; Hypertrophy; Intervertebral Disc; Joints; Male; Osteoblasts; Osteoclasts; Rats; Rats, Sprague-Dawley; Stress, Mechanical; Tail; Tetracycline

This study investigates whether bisphosphonate-treated rats are still able to adapt to low calcium supply through an increase in bone resorption assessed by measuring the urinary excretion of [3H]-tetracycline from chronically prelabeled rats. First it was shown that in this model, parathyroid hormone was responsible for the increase in bone resorption on the low calcium diet. In the second part, animals were treated with the three bisphosphonates-clodronate, alendronate, and ibandronate-given in two doses. Animals receiving a dose that already strongly inhibits bone resorption were still able to respond to a low calcium diet by increasing bone resorption, showing the potency of the latter as a stimulator of bone resorption. Higher doses were, however, able to blunt this response. As soon as the treatment was discontinued, this increase in bone resorption resumed with clodronate but not with alendronate or ibandronate.

Topics: Alendronate; Animals; Bone Resorption; Calcium; Calcium, Dietary; Clodronic Acid; Diphosphonates; Disease Models, Animal; Homeostasis; Ibandronic Acid; Male; Rats; Rats, Wistar; Tetracycline

The last 25 years have brought unprecedented advances to our understanding of periodontal disease. Consider that in 1970 periodontitis was believed to effect most individuals over the age of 35 years, to progress steadily in an individual once initiated until teeth were lost, to be the primary cause of tooth loss in adults, to be caused by the bacterial mass accumulating on the tooth surface and subgingivally, and to involve the host in some fashion or another. In the 25 years since then, impressive research advances in the epidemiology of periodontal disease, the specific bacterial etiology of periodontal disease and the immunoinflammatory mediators of periodontal tissue destruction have greatly altered our view of periodontal disease. Thus, given these research advances in the understanding of periodontitis, what may the future hold for improved diagnosis and treatment of periodontal disease? Impressive research into new ways to diagnose the periodontal diseases is well underway. Investigators are seeking new ways to diagnose an individual's degree of risk for periodontal disease initiation, susceptibility to disease progression, level of disease "activity" and the likely response to treatment and recurrence of active disease. New diagnostic tests should greatly advance our ability to more accurately and specifically diagnose periodontal disease. The future also looks promising for new treatment strategies to slow or arrest periodontal disease progression. The bacterial specificity of periodontal disease etiology revealed since 1970 has logically led to the use of antibiotics in periodontitis treatment. In the late 1980s the concept of locally delivering antibiotics to the periodontal pocket was introduced, and subsequent clinical trials have indicated that it is possible to reduce pocket depth and inflammation with tetracycline locally delivered to the periodontal pocket. Likely, we have barely scratched the surface in studying the efficacy of locally delivery antimicrobial agents to alter the progression of periodontal disease. As new agents are developed and better delivery systems to the periodontal pocket are developed, the future should see a variety of antimicrobial agents available which can slow periodontal disease progression. The future also holds promise for slowing periodontal disease progression by blocking inflammatory pathways important in periodontal tissue destruction. Clinical trials of flubiprofen, naproxen and ketoprofen indicate th

Topics: Adult; Animals; Anti-Bacterial Agents; Anti-Infective Agents, Local; Anti-Inflammatory Agents; Anti-Inflammatory Agents, Non-Steroidal; Bacterial Physiological Phenomena; Disease Models, Animal; Disease Progression; Disease Susceptibility; Drug Delivery Systems; Enzyme Inhibitors; Forecasting; Humans; Inflammation Mediators; Matrix Metalloproteinase Inhibitors; Periodontal Diseases; Periodontitis; Recurrence; Risk Factors; Technology, Dental; Tetracycline; Tooth Loss

The aims of the present study were to assess the usefulness of the Helicobacter felis mouse model in the evaluation of antimicrobial therapies and the effect of Helicobacter infection on gastric mucosal prostaglandin E2 release.. Barrier-maintained BALB/c mice were infected with H. felis and treated with different antibacterial therapies. H. felis status was determined by bacterial culture, urease test, and bacterial and histologic stainings. Release of prostaglandin E2 from the gastric mucosa was measured by radioimmunoassay.. All triple-treated mice were cleared of bacteria both 24 h and 1 month after treatment. However, tinidazole alone also resulted in 100% eradication. Monotherapies with erythromycin acistrate, tetracycline, colloidal bismuth subcitrate, and nitecapone failed to eradicate the bacteria. The release of gastric prostaglandin E2 was doubled in the infected mice (554 +/- 39, mean +/- SE) compared with the noninfected mice (270 +/- 35) (p < 0.01).. The H. felis mouse model proved satisfactory for assessing both anti-Helicobacter therapies and the prostaglandin E2 release. The reliability of this method was improved when several methods to assess the H. felis status were used in parallel.

Topics: Amoxicillin; Animals; Anti-Ulcer Agents; Catechols; Dinoprostone; Disease Models, Animal; Drug Therapy, Combination; Erythromycin; Gastric Mucosa; Helicobacter Infections; Male; Mice; Mice, Inbred BALB C; Organometallic Compounds; Pentanones; Tetracycline; Tinidazole

When administered intermittently, parathyroid hormone (PTH) is a potent anabolic agent in both human and animal bone. To improve our understanding of this anabolic effect, we have examined the time course of PTH action in an established animal model of estrogen deficiency-induced bone loss: the ovariectomized rat. Animals were ovariectomized (Ovx) and allowed to lose bone for 6 weeks. A dose of 20 micrograms/kg/d of rat PTH (1-34) was administered s.c., 6 days each week for periods of 1, 2, 3, 4, 6 and 8 weeks. Animals were sacrificed for evaluation of skeletal histomorphometry of the proximal tibia and mechanical strength of the cancellous bone in the marrow cavity of the distal femur. Cancellous bone volume (Cn-BV/TV) increased gradually over 8 weeks of treatment (16.8 +/- 1.6 to 24.1 +/- 2.7%) as did the bone formation rate (0.308 +/- 0.054 to 1.659 +/- 0.293 microns3/micron2/d), as determined by an increase in both total mineralization surface (15.5 +/- 2.1 to 42.7 +/- 5.0%) and mineral apposition rate (1.88 +/- 0.20 to 3.55 +/- 0.39 microns/d). The largest increments in these variables reflecting bone formation occurred over the first week of treatment. This bone formation was accompanied by an increase in trabecular thickness (Tb.Th) (55.3 +/- 3.4 to 80.5 +/- 5.0 microns) without a corresponding increment in trabecular number (Tb.N) (3.65 +/- 0.17 to 3.55 +/- 0.26). Extensive tetracycline labels were visualized on the surface of trabecular rod-like and plate-like structures. A small transient, though not statistically significant, increase occurred in both eroded surface and urinary pyridinoline concentration immediately after the onset of PTH administration. Osteocalcin showed a small decrement in the first two weeks after PTH administration, but the levels were elevated when compared with the Ovx control in later weeks. Mechanical strength of the cancellous bone also increased significantly with PTH treatment (20.5 +/- 2.4 to 46.1 +/- 10.0 Newtons). Our results showed that: 1) intermittent PTH treatment of Ovx rats elicited an immediate increase of bone formation activity by the existing osteoblasts, 2) the increase of Cn-BV/TV after PTH administration resulted primarily from an increase in Tb.Th, and 3) improved mechanical strength after PTH treatment can be achieved by increases in Tb.Th without an increase in Tb.N.

Topics: Amino Acids; Analysis of Variance; Animals; Biomechanical Phenomena; Bone Density; Bone Development; Disease Models, Animal; Estrogens; Female; Femur; Humans; Injections, Subcutaneous; Microscopy, Electron, Scanning; Microscopy, Fluorescence; Osteocalcin; Osteoporosis, Postmenopausal; Ovariectomy; Parathyroid Hormone; Rats; Rats, Sprague-Dawley; Tetracycline; Tibia

Estrogen deficiency in rats is responsible for increased osteoclastic resorption and a subsequent rapid bone loss. TGF-beta, which is known to have acute effects on bone resorption in several in vitro models, has been shown to be secreted by osteoblastic cells in vitro in response to 17 beta-estradiol, but little is known about its in vivo effects on bone resorption. We therefore decided to investigate the short-term effect of TGF-beta 1 on bone resorption in ovariectomized rats. TGF-beta 1 (0.04-20 ng/injection), or vehicle, was injected daily directly into the bone marrow space, through a thin catheter implanted in the distal end of the right femur, during 4 consecutive days, starting 14 days after the ovariectomy. Bone histomorphometry was performed in the secondary spongiosa of the metaphysis of injected femurs and compared with vehicle-injected femurs of sham ovariectomized rats. Ovariectomy was associated with a marked increase in the resorption surface, a 2-fold increase in the number of osteoclasts, and no change in the number of TRAP-positive marrow cells distant from bone surfaces. Bone resorption was significantly lower in the TGF-beta 1-injected bones of ovariectomized rats, as compared with vehicle injected bones: the osteoclast surface and the number of osteoclasts were, respectively, 11.0 +/- 5.1% versus 20.8 +/- 1.3% and 287 +/- 41 versus 505 +/- 53, in bones injected with 0.2 ng of TGF-beta 1 as compared with vehicle-injected bones (mean +/- SE, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Analysis of Variance; Animals; Bone Development; Bone Marrow; Bone Resorption; Catheterization; Disease Models, Animal; Dose-Response Relationship, Drug; Estrogens; Female; Femur; Humans; Osteoclasts; Osteoporosis, Postmenopausal; Ovariectomy; Rats; Rats, Sprague-Dawley; Tetracycline; Transforming Growth Factor beta

Clinical studies in thyrotoxicosis reveal a state of high bone turnover leading, eventually, to osteoporosis. Recently there has been concern that thyroxine (T4) treatment may have a similar effect on bone. Rat models have been used to study the effects of T4 on bone, but the majority of studies have looked at the effects of T4 after only 3 weeks of treatment. The aim of this study was to evaluate histomorphometric changes in rats after 12 weeks of thyroxine overtreatment or 12 weeks of hypothyroidism compared with untreated control animals. Animals received either T4 200 micrograms/kg per day, 0.1% propylthiouracil, or vehicle for 12 weeks. Tetracycline was administered 1 week and 3 weeks prior to killing. Iliac crest bone was used for histomorphometry. Serum T4 measurements (taken at killing) confirmed hyper- and hypothyroidism in the appropriate animal groups (between group difference p < 0.001 by ANOVA). In hyperthyroid animals there was an increase in mineral apposition rate (MAR; 0.94 vs. 0.59 microns/day, p < 0.001) and mineral formation rate (MFR/BS; 0.24 vs. 0.12 x 10(-2) micron3/micron2 per day, p < 0.001) and a slight increase in eroded surfaces (ES/BS%; 1.54 vs. 1.36, p < 0.05) compared with controls, consistent with previous in vitro and in vivo observations. In hypothyroid rats there was a marked reduction in osteoid surfaces (OS/BS%; 1.7 vs. 24.8, p < 0.001) and MAR (0.3 vs. 0.59 micrograms/day, p < 0.001), a reduction in ES/BS% (0.51 vs. 1.36, p < 0.05), and an increase in cancellous bone volume (BV/TV%; 30.29 vs. 19.6, p < 0.05), suggesting that thyroid hormones are a requirement for normal bone turnover.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Analysis of Variance; Animals; Body Weight; Calcinosis; Disease Models, Animal; Drug Overdose; Hyperthyroidism; Hypothyroidism; Ilium; Male; Propylthiouracil; Radioimmunoassay; Rats; Rats, Wistar; Tetracycline; Thyroid Function Tests; Thyroxine

The effects of 5, 10, and 20% dietary xylitol supplementations on the resorption of bone were studied. The resorption was measured by the urinary excretion of [3H] radioactivity from [3H]tetracycline-prelabeled rats. The 10 and 20% oral xylitol administrations caused a significant decrease in the excretion of [3H] as compared with the control group with no xylitol supplementation. The effect was detected as early as 2 days after the beginning of xylitol-feeding and was maintained throughout the experimental period of 31 days. The retarding effect on bone resorption was about 25% in the 10% xylitol group, about 40% in the 20% xylitol group, and undetectable in the 5% xylitol group. The amount of preserved [3H] radioactivity in the tibiae of the 10 and 20% xylitol groups after the experiment clearly exceeded the values of the control group. The mechanism of the retarded bone resorption caused by dietary xylitol still remains obscure, but an increased absorption of calcium may be involved. In conclusion, dietary xylitol supplementation in rats seems to retard the bone resorption in a dose-dependent way. The effect is achieved rapidly and is maintained at least over a period of 1 month xylitol feeding.

Topics: Administration, Oral; Analysis of Variance; Animals; Bone Resorption; Diet; Disease Models, Animal; Dose-Response Relationship, Drug; Isotope Labeling; Male; Rats; Rats, Wistar; Tetracycline; Tritium; Xylitol

Poly(ortho esters) prepared by the condensation of 1,2,6-hexanetriol and an alkyl orthoacetate are viscous, semisolid materials at room temperature that can be injected using a blunt needle. When tetracycline was incorporated into these materials, complete release occurred within about 24 hours, but when small amounts of Mg(OH)2 were incorporated into the polymer release could be extended to many weeks, and a loading of 0.5 wt% resulted in sustained release of about 10 days. When adhesion was tested using bovine teeth, cohesive failure of the pure polymer occurred at a force of about 392 mN cm-2 and cohesive failure of a polymer incorporating 10 wt% tetracycline and 1 wt% (Mg(OH)2 occurred at about 118 mN cm-2. The combination of injectability, dentoadhesiveness and ability to control accurately the release of incorporated antibiotics makes these materials promising candidates for bioerodible delivery systems useful in the treatment of periodontitis. Toxicological studies are currently in progress.

Topics: Acetates; Animals; Biodegradation, Environmental; Cattle; Delayed-Action Preparations; Disease Models, Animal; Drug Delivery Systems; In Vitro Techniques; Magnesium Hydroxide; Periodontitis; Polyesters; Tetracycline; Tooth

The efficacy of ciprofloxacin, norfloxacin and tetracycline in prevention of colonisation of V. cholerae O1 in the rabbit intestine were tested. V. cholerae O1 highly colonised the gut of rabbits which did not receive any antibiotic. All antibiotics tested inhibited the colonisation of V. cholerae O1 within the rabbit intestine. Moreover, ciprofloxacin and norfloxacin were found to be as effective as tetracycline suggesting that these drugs should be subjected to clinical trials for the treatment of cholera in comparison with tetracycline.

Topics: Animals; Anti-Bacterial Agents; Cholera; Ciprofloxacin; Disease Models, Animal; Evaluation Studies as Topic; Intestines; Microbial Sensitivity Tests; Norfloxacin; Rabbits; Tetracycline; Vibrio cholerae

In vivo and in vitro efficacy of tetracyclines was studied with respect to anthracic infection induced by a tetracycline-resistant resistant strain containing plasmid pBC16. The plasmid-containing strain was resistant to tetracycline, doxycycline and minocycline, the MICs exceeding those for the initial strain 500, 640 and 80 times, respectively. There was no therapeutic effect of tetracycline and doxycycline in the treatment and urgent prophylaxis of anthracic infection caused by the tetracycline-resistant strain of Bacillus anthracis. High therapeutic efficacy of minocycline in the average therapeutic concentrations was shown irrespective of the contaminating doses and strains. Minocycline was recommended for treatment and urgent prophylaxis of anthracic infection caused by tetracycline-resistant B. anthracis strains.

Topics: Animals; Anthrax; Bacillus anthracis; Cricetinae; Disease Models, Animal; Doxycycline; Drug Resistance, Microbial; Genes, Bacterial; In Vitro Techniques; Mesocricetus; Mice; Minocycline; R Factors; Tetracycline; Tetracycline Resistance

The present study investigated the prophylactic effects of vitamin D metabolites and vitamin D metabolite combinations on static and dynamic, tetracycline-based, histomorphometric parameters in the axial skeleton of ovariectomized rats. Forty-three Fischer-344 rats (10 weeks old, 130 g each body weight, BW) were either bilaterally ovariectomized (OVX) or sham-operated (SHAM). The rats were allocated into the following groups: SHAM; OVX; OVX + 7.5 ng 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3]/rat/day; OVX + 15 ng 1 alpha,24R,25-trihydroxyvitamin D3 [1,24,25-(OH)3D3]/rat/day; OVX + 75 ng 24R,25-dihydroxyvitamin D3 [24,25(OH)2D3]/rat/day; OVX + 7.5 ng 1,25(OH)2D3/rat/day + 15 ng 1,24,25(OH)3D3/rat/day; OVX + 7.5 ng 1,25(OH)2D3/rat/day + 75 ng 24,25(OH)2D3/rat/day. The vitamin D metabolites were fed orally starting 4 weeks after surgery. Urine and blood samples were collected 12 and 16 weeks postovariectomy, respectively. Sixteen weeks after surgery, all rats were sacrificed, and the first lumbar vertebrae were processed undecalcified for histomorphometric analysis. Ovariectomy induced a highly significant reduction (P less than 0.001) of cancellous bone mass in the secondary spongiosa of the lumbar vertebral body. The bone loss in OVX rats was accompanied by a distinct elevation of all histomorphometric parameters of bone formation and resorption. 1,25(OH)2D3 and both vitamin D metabolite combinations significantly raised serum calcium levels and prevented the bone loss by inhibiting the increased bone resorption in OVX rats. In the applied dosage, 1,24,25(OH)3D3 and 24,25(OH)2D3 alone were ineffective in preserving the cancellous bone of the lumbar vertebra in OVX rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Body Weight; Bone Diseases, Metabolic; Bone Resorption; Calcitriol; Disease Models, Animal; Drug Evaluation, Preclinical; Female; Humans; Hydroxycholecalciferols; Lumbar Vertebrae; Osteoporosis, Postmenopausal; Ovariectomy; Rats; Rats, Inbred F344; Tetracycline

A murine model of severe combined immunodeficiency syndrome (scid mice) affords an opportunity to study the interaction of Candida albicans with a host lacking functional B- and T-cell mechanisms. We have previously reported no significant difference in yeast recovery after intravenous challenge of BALB/c mice and scid mice with C. albicans (S. Mahanty, R.A. Greenfield, W.A. Joyce, and P.W. Kincade, Infect. Immun. 56:3162-3166, 1988). In this study, we evaluate the course of gastrointestinal candidiasis after a single oral challenge with C. albicans. BALB/c and scid mice received H2O containing 10(6) C. albicans per ml for 16 h. Half the mice of each strain continuously received H2O containing 1 mg of tetracycline per ml. Stool samples were cultured for yeast twice weekly until they were negative three consecutive times or positive for 8 weeks. Mice were then sacrificed for quantitative cultures of liver, spleen, and kidneys. At eight weeks postinoculation, 2 of 13 BALB/c mice, 0 of 14 BALB/c mice receiving tetracycline, 6 of 12 scid mice, and 8 of 13 scid mice receiving tetracycline had positive stool cultures (P less than 0.05, likelihood ratio chi-square). Quantitative recovery of yeasts from stools was also higher in the scid mice. Cultures of liver, spleen, and kidneys wer negative in all BALB/c mice and essentially all negative in scid mice; a single colony was isolated from the kidney of one scid mouse and the liver of another scid mouse. We conclude that B cells and/or T cells and their products are important in gastrointestinal colonization with C. albicans but that even in their absence, dissemination of infection from the gastrointestinal tract does not consistently occur. Thus, other aspects of host defense must be critical in containing gastrointestinal Candida colonization.

Topics: Administration, Oral; Animals; Candida albicans; Candidiasis; Colony Count, Microbial; Disease Models, Animal; Disease Susceptibility; Female; Gastrointestinal Diseases; Immunologic Deficiency Syndromes; Mice; Mice, Inbred BALB C; Random Allocation; Tetracycline

Interferon (IF)-inducing capacity of C. trachomatis was shown in experiments on mice CBA. The levels of IF production in the parenchymatous organs correlated with accumulation of the pathogen in them. The use of larifan, a natural double-stranded IF inductor, according to the treatment scheme provided high levels of endogenic IF in infected mice. It inhibited multiplication of Chlamydiae in the lungs and lymph nodes detected cytoscopically by light and fluorescence microscopy and with infection titration. The effect of the inductor combined with tetracycline was of additive nature. Double intraperitoneal administration of larifan with an account of the hyporeactivity phase and daily administration of tetracycline proved to be the most efficient. It is possible to successfully use IF inductors in accordance with the treatment schemes in infection caused by C. trachomatis which makes promising their clinical application in therapy of chlamydiosis.

Topics: Animals; Chlamydia Infections; Chlamydia trachomatis; Disease Models, Animal; Drug Synergism; In Vitro Techniques; Interferon Inducers; Interferons; Mice; Mice, Inbred CBA; Organic Chemicals; Tetracycline

We have validated an established animal model of acute inflammatory bowel disease in indomethacin-treated rats. Studies in both in vitro and in vivo 51chromium-labelled ethylenediamine tetra-acetate (51Cr-EDTA) permeability and tissue myeloperoxidase activity, a marker of inflammatory cell invasion, showed increased permeability and enzyme levels, respectively, in treated animals compared to controls (in vitro 51Cr-EDTA permeability: (mean (SE] control 0.10 (0.02) microliter/mg per tissue, experimental 0.17 (0.02) (p < 0.01, 2 way analysis of variance); in vivo 51Cr-EDTA permeability: control 3.9 (1.3) (% dose recovered), experimental 12.1 (1.5) (p < 0.01); tissue myeloperoxidase: control 10.8 (0.4) mU/mg, experimental 17.2 (0.5) p less than 0.01). Pretreatment or simultaneous treatment of indomethacin-treated animals with glucocorticoids, sulphasalazine, or tetracycline reduced the permeability changes and the tissue inflammatory response (in vitro 51Cr-EDTA permeability: (mean (SE] sulphasalazine + indomethacin 0.11 (0.2) microliter/mg tissue (p < 0.01), prednisolone +/- indomethacin 0.12 (0.02) (p < 0.01), tetracycline + indomethacin 0.12 (0.02) (p < 0.01]. Glucocorticoids and sulphasalazine, but not tetracycline, administered after the indomethacin also partially corrected the permeability and inflammatory changes induced by indomethacin (in vitro 51Cr-EDTA permeability: sulphasalazine 0.15 (0.02) microliter/mg, p < 0.02; prednisolone 0.12 (0.02) microliter/mg, p < 0.01). This approach was used to investigate the effects of two different thromboxane synthetase inhibitors in indomethacin-treated animals. Simultaneous treatment with thromboxane synthetase inhibitors and indomethacin prevented the 51Cr-EDTA permeability and tissue myeloperoxidase increases induced by indomethacin alone (in vitro 51Cr-EDTA permeability: thromboxane synthetase inhibitors + indomethacin 0.11 (0.01) microliter/mg (p0.01); tissue myeloperoxidase: 11 (0.4) mU/mg, (p < 0.01). Thromboxane synthetase inhibitors administered after the indomethacin also partially corrected the permeability and inflammatory changes induced by indomethacin (in vitro 51Cr-EDTA permeability: thromboxane synthetase inhibitors 0.12 (0.02) mU/mg (p < 0.01); tissue myeloperoxidase 13.8 (0.5) (p < 0.01). These studies indicate that thromboxane synthetase inhibitors partially correct the intestinal lesion non-steroidal anti-inflammatory drug enteropathy and may therefore be of use in inflammatory bowel disea

Topics: Animals; Cell Membrane Permeability; Chromium Radioisotopes; Disease Models, Animal; Edetic Acid; Ileum; Imidazoles; Indomethacin; Inflammatory Bowel Diseases; Jejunum; Male; Peroxidase; Prednisolone; Rats; Rats, Inbred Strains; Sulfasalazine; Tetracycline; Thromboxane-A Synthase

Drugs in the tetracycline family can inhibit mammalian tissue collagenase both in vitro and in vivo by a mechanism that is independent of antibiotic action. The epiphyseal cartilages of rachitic rats contain extremely high levels of collagenase (CGase), and we have used this model to study further the phenomenon of tetracycline inhibition of tissue CGase. Rickets was induced in rats by phosphate/vitamin D deficiency and parameters of gross bone morphology, bone chemistry, and serum chemistry were evaluated in both rachitic and nonrachitic animals with and without treatment with oral tetracyclines (TETs). Minocycline (or doxycycline) partially suppressed the appearance of many of the expected changes in the rachitic animals, including gross bone hardness, growth plate widening, long bone length, suppression of weight gain, and decreased bone ash content. The effects were dose dependent and were associated with marked suppression of the enhanced CGase activity. Examination of collagen breakdown products by SDS-PAGE documented that the rachitic enzyme behaved like other mammalian collagenases including in vitro inhibition with minocycline 10-20 micrograms/ml and with a nonantibiotic tetracycline. No evidence of TET osseous toxicity was noted, and, in fact, administration of TET to nonrachitic animals had a mildly favorable effect on growth and development. TET suppression of CGase can be demonstrated in a well defined model system and this form of pharmacologic enzyme inhibition can be a useful probe for delineating the role of the enzyme in connective tissue pathology.

Topics: Animals; Disease Models, Animal; Dose-Response Relationship, Drug; Doxycycline; Growth Plate; Microbial Collagenase; Minocycline; Rats; Rats, Inbred Strains; Rickets; Tetracycline

Immune consequences of gastrointestinal colonization of CD-1 and CBA/J mice with Candida albicans in the presence or absence of continuous antibiotic treatment with penicillin-tetracycline or trimethoprimsulfamethoxazole were investigated. Intubation with C. albicans in the absence of antibiotics resulted in the induction of low but detectable delayed-type hypersensitivity (DTH), demonstrable by footpad testing with a C. albicans wall glycoprotein (GP), and in the stimulation of a moderate level of protective immunity, demonstrable by intravenous (i.v.) challenge. DTH to a membrane extract, BEX, could not be detected in such animals. However, animals colonized in the presence of antibiotics and then inoculated cutaneously prior to being tested for DTH or protective immunity developed significantly enhanced levels of DTH to GP and BEX and were protected to an even greater extent than animals colonized in the absence of antibiotics who were not inoculated cutaneously. The priming effect of colonization, particularly with respect to the antigen GP, was also obvious from an enzyme-linked immunosorbent assay for GP-specific antibody with sera of mice surviving the i.v. challenge, in that GP-specific antibody was present in the highest titers in colonized animals that had been inoculated cutaneously prior to i.v. challenge. While the antibiotics promoted higher levels of colonization, as evidenced by stomach and fecal cultures of intubated mice, antibiotic administration was not necessary for the induction of C. albicans-specific responses. Moreover, contrary to reports in the literature, antibiotic administration had no adverse effect on the immune responses measured. Females were innately more resistant than males to i.v. challenge with C. albicans, but each sex was capable of developing protective immunity of equal intensity in response to colonization or immunization by cutaneous challenge.

Topics: Animals; Antibodies, Fungal; Candida albicans; Candidiasis; Disease Models, Animal; Drug Combinations; Enzyme-Linked Immunosorbent Assay; Female; Hypersensitivity, Delayed; Immunity, Cellular; Immunization; Male; Mice; Mice, Inbred CBA; Penicillins; Stomach; Sulfamethoxazole; Tetracycline; Trimethoprim; Trimethoprim, Sulfamethoxazole Drug Combination

The detection of the differentiated chemotherapeutic activity of tetracyclin and penicillin has been used as an example for demonstrating the possibility of using the experimental in ovo model of mixed chlamydial and gonococcal infection for the detection and primary selection of effective etiotropic preparations, simultaneously affecting Chlamydia trachomatis and Neisseria gonorrhoeae.

Topics: Animals; Chick Embryo; Chlamydia Infections; Chlamydia trachomatis; Disease Models, Animal; Drug Evaluation, Preclinical; Gonorrhea; Neisseria gonorrhoeae; Penicillin G; Tetracycline; Time Factors; Yolk Sac

The intradermal injection of 140 micrograms of Propionibacterium acnes (CN 6134) into the ears of female Sprague-Dawley rats produced a chronic inflammation with formation of acneiform lesions. Inflammation was characterized by more than a doubling of ear thickness at 24 h and a peak of 3-4 times control levels at day 21. At 42 days post injection ears were still 3 times normal thickness. Histologically there was early polymorph accumulation giving way to macrophages and lymphocytes by day 7. Pilosebaceous follicles overlying the inflamed area lost their sebaceous glands and became hyperplastic cords of cells that grew down and encapsulated inflammatory loci. By day 9 many of these follicles had become secondary comedones. Three isolates of P. acnes from inflammatory acne lesions and 4 of 5 isolates from non-acne patients produced results similar to that of the strain CN 6134. In these cases the number of histologically evident secondary comedones was correlated with ear thickness. In contrast, samples of Streptococcus lactis, Escherichia coli B, and Staphylococcus epidermidis failed to produce this combination of chronic inflammation and high lesion count. Benzoyl peroxide, tetracycline, erythromycin, phenidone, naproxen, and cis and trans retinoic acid were inactive as inhibitors of P. acnes CN 6134-induced ear thickening. The corticosteroid fluocinolone acetonide produced dramatic suppression of inflammation, but upon cessation of treatment the ears returned to inflamed levels. The specificity for P. acnes, the formation of acneiform lesions, and the recalcitrance of the inflammation suggest our model is indeed relevant to acne.

Topics: Acne Vulgaris; Animals; Benzoyl Peroxide; Disease Models, Animal; Erythromycin; Female; Fluocinolone Acetonide; Inflammation; Injections, Intradermal; Naproxen; Propionibacterium acnes; Pyrazoles; Rats; Rats, Inbred Strains; Tetracycline; Tretinoin

Strains of Campylobacter jejuni and C coli from human and animal sources were assessed for pathogenicity by their capability to produce abortions in pregnant guinea pigs. The pathogenicity rate varied from 7% to 87% for the C jejuni strains and from 0% to 53% for the C coli strains. Plasmid carriage was not found to correlate with pathogenicity as determined by ability of the strains to produce abortions in the pregnant guinea pig model.

Topics: Abortion, Veterinary; Animals; Campylobacter; Campylobacter fetus; Disease Models, Animal; DNA, Bacterial; DNA, Circular; Drug Resistance, Microbial; Female; Guinea Pigs; Molecular Weight; Plasmids; Pregnancy; Tetracycline

The effectiveness of tetracycline therapy on Listeria-infection in compromised host was evaluated in three different murine models. In normal adult mice infected with a tetracycline susceptible strain of Listeria monocytogenes, treatment with this antibiotic caused a reduced rate of multiplication of bacteria. That is, a low bacterial count was found in the spleen. When the macrophage system which in Listeria-infection represents a major defense mechanism was blocked through dextran sulfate 500, treatment with tetracycline was still very effective. In this case, bacterial multiplication has ceased. However, an elimination of the organisms could only be achieved after the macrophage system recovered from its temporary blockade. Secondly, nude athymic mice which are unable to develop cell mediated immunity were used to establish chronic infection with Listeria. Treatment with tetracycline in this instance only reduced bacterial counts moderately. Thirdly, five days old baby mice which are extremely susceptible to Listeria could at least partially be protected with tetracycline therapy against fatal infection.

Topics: Animals; Animals, Newborn; Dextran Sulfate; Dextrans; Disease Models, Animal; Female; Listeria monocytogenes; Listeriosis; Macrophages; Mice; Mice, Nude; Phagocytosis; Tetracycline

The role of iron deficiency in the development of oral candidosis was investigated using the mouse mutant sex-linked anaemia (sla). Susceptibility was assessed in terms of the recovery of organisms, particularly from oral swabs, and histological evidence of infection approximately 10 days after the last exposure to Candida albicans. The influence of three factors was studied in mixed groups of normal and anaemic mice: mode of inoculation, treatment with tetracycline and treatment with hydrocortisone. The most susceptible group had received drinking water containing tetracycline (1 mg/ml), hydrocortisone (0.1 mg/ml) and candida (5 X 10(4) c.f.u./ml for 6 days). Anaemic mice showed a rather higher rate of recovery of organisms and more frequent histological evidence of infection than normal mice in certain groups. Neither of these tendencies was statistically significant alone but, taken together, they suggest that some small difference of susceptibility may exist between normal mice and mice with sla. The mouse model could be of value in studying the influence of several other inherited disorders on susceptibility to candidosis.

Topics: Anemia, Hypochromic; Animals; Candidiasis; Disease Models, Animal; Hydrocortisone; Male; Mice; Mice, Mutant Strains; Tetracycline

Erythromycin and rifampicin (rifampin) were able to prevent death of guineapigs given intraperitoneal injections of the agent causing legionnaires' disease. Penicillin, chloramphenicol, tetracycline, and gentamicin showed no significant effect. On the basis of clinical experience and experimental observations, erythromycin is recommended for patients suspected to have legionnaires' disease. Combined therapy with erythromycin and rifampicin may be justified in patients with confirmed legionnaires' disease who are not responding to erythromycin alone or as part of a controlled antibiotic trial among suspected cases during an outbreak of legionnaires' disease.

Topics: Administration, Oral; Animals; Chloramphenicol; Disease Models, Animal; Drug Evaluation; Drug Evaluation, Preclinical; Drug Therapy, Combination; Erythromycin; Female; Gentamicins; Guinea Pigs; Injections, Subcutaneous; Legionnaires' Disease; Penicillins; Respiratory Tract Infections; Rifampin; Tetracycline

Topics: Animals; Brain; Candida albicans; Candidiasis; Cortisone; Disease Models, Animal; Kanamycin; Organ Specificity; Rats; Tetracycline

Topics: Animals; Cardiomyopathies; Disease Models, Animal; Isoproterenol; Myocardium; Rats; Technetium; Tetracycline; Tin

The influence of tsutsugamushi fever infection on the metabolism of blood lymphocytes of mice differing in susceptibility to Rickettsia tsutsugamushi and of rifampicine and tetracycline treatment was studied. In susceptible mice, the activity of oxidation-reduction processes in lymphocytes increased at 7--10 days of the disease and became normal upon recovery of the animals. In mice with low susceptibility this increase of the activity began and terminated much earlier, at 3--5 days. Treatment of the infection with antibiotics resulted in a rapid arrest of the disease and normalization of the lymphocyte activity. The relationship between susceptibility of the animals to R. tsutsugamushi and the activity of oxidation-reduction enzymes is discussed on the example of succinate dehydrogenase.

Topics: Animals; Antibodies, Bacterial; Disease Models, Animal; Lymphocytes; Mice; Orientia tsutsugamushi; Rifampin; Scrub Typhus; Succinate Dehydrogenase; Tetracycline

The minimal growth inhibiting concentration of tiamulin, a derivative of the diterpen antibiotic pleuromutilin, was evaluated in vitro against 11 different serogroups of leptospira interrogans by twofold serial dilution technique, in comparison to tetracyclin, dihydrostreptomycin and tylosin. The range of the MIC values of tiamulin is between 0.07 and 2.5 microgram/ml and thus comparable to the activities of the standard antibiotics tested (see table 1). The chemotherapeutic efficacy (ED50) of the compound was examined in two experimental leptospiral infections of the Syrian hamster, in comparison to tetracyclin. Both compounds were administered orally for 3 days. In the L. canicola infection, the ED50 values were 103.8 mg/kg and 306.3 mg/kg body-weight for tiamulin and tetracyclin, respectively. In the L. grippotyphosa infection, the ED50 values amounted to 35.16 and 277.5 mg/kg bodyweight for tiamulin and tetracyclin, respectively. Based on these values, tiamulin in comparison to tetracyclin showed 3-8 fold higher efficacy in vivo after oral administration.

Topics: Animals; Anti-Bacterial Agents; Cricetinae; Dihydrostreptomycin Sulfate; Disease Models, Animal; Diterpenes; Drug Evaluation, Preclinical; Female; Leptospira; Leptospirosis; Leucomycins; Male; Mesocricetus; Species Specificity; Tetracycline

Myocardial contusions of variable severity were experimentally produced by an air-driven piston or serrated clamp in 29 dogs. Two 99mTc-labeled bone-seeking agents (99mTc pyrophosphate and 99mTc tetracycline) were used with cardiac scintigraphy to determine the sensitivity of these agents in detecting different degrees of myocardial damage. Results showed that 99mTc tetracycline was not a suitable scanning agent. 99mTc pyrophosphate produced positive scans in cases of complete (or nearly complete) transmural myocardial necrosis. Positive cardiac scans in clinical myocardial contusion may indicate the severity of the lesions and have prognostic significance.

Topics: Animals; Contusions; Disease Models, Animal; Dogs; Heart Injuries; Radionuclide Imaging; Technetium; Tetracycline; Tin Polyphosphates

The efficacies of five common antimicrobial agents were determined for a pure Bacteroides fragilis infection in mice. Therapy was begun 4 h after bacterial injection and given every 8 h thereafter for 5 days. Blood levels were determined over an 8-h period for each concentration of antibiotic tested. Clindamycin and tetracycline were the most effective in preventing the formation of abscesses. Chloramphenicol, penicillin G, and cephalothin were not effective in protecting the mice from infection.

Topics: Abscess; Animals; Bacteroides fragilis; Bacteroides Infections; Cephalothin; Chloramphenicol; Clindamycin; Disease Models, Animal; Mice; Mice, Inbred ICR; Microbial Sensitivity Tests; Penicillin G; Tetracycline

Giardia muris has been maintained for years in the mouse by administering by gavage 10,000 trophozoites taken from the small intestine of infected mice. Despite the growth of numerous protozoa in the intestine, absorption of tetracycline hydrochloride in infected mice was not changed to a statistically significant extent, as blood drug levels increased only slightly: behavior was similarly unaffected. Reasons for the apparent lack of virulence of this strain are discussed.

Topics: Administration, Oral; Animals; Disease Models, Animal; Giardia; Giardiasis; Intestinal Absorption; Mice; Tetracycline; Virulence

The in vivo antibacterial effectiveness in the rabbit cornea of a number of commercially available ophthalmic antibiotic preparations was determined against a single strain of penicillinase-producing Staphylococcus aureus isolated from a human corneal ulcer. Each antibiotic was instilled topically at hourly intervals, and the number of residual viable organisms in the cornea subsequently was ascertained. In vivo measurements demonstrated that five antibiotics--neomycin sulfate, gentamicin sulfate, erythromycin, tetracycline hydrochloride, and chlortetracycline hydrochloride--were equally effective in suppressing growth of the strain of S aureus studied. Therapeutic results were the same whether the corneal epithelium was present of absent for each of the drugs studied. With one exception (chloramphenicol), there was excellent correlation between in vivo and in vitro findings.

Topics: Administration, Topical; Animals; Anti-Bacterial Agents; Chlortetracycline; Disease Models, Animal; Erythromycin; Gentamicins; Humans; In Vitro Techniques; Keratitis; Neomycin; Ophthalmic Solutions; Rabbits; Staphylococcal Infections; Staphylococcus aureus; Tetracycline

The effects of the dimethyl quarternary analog of propranolol, UM-272, on myocardial infarct volume were studied in the canine heart. Myocardial infarction was produced by occlusion of the left circumflex coronary artery for 60 minutes followed by reperfusion and quantitation of infarct volume 24 hours later. Groups of dogs were either untreated or pretreated with UM-272 with an initial loading dose of 5.0 mg/kg (group A) or 2.5 mg/kg (group B) 30 minutes before occlusion of the left circumflex coronary artery. Both group A and group B animals received additional doses of 2.5 mg/kg of UM-272 every 90 minutes for a period of 6 hours so that the total respective doses were 15 and 12.5 mg/kg. Control animals received comparable volumes of 0.9% sodium chloride solution. All animals were followed throughout the 6-hour procedure with continuous electrocardiographic recordings which were used to assess the effects of acute myocardial ischemia upon disturbances in cardiac rhythm and the effects of drug treatment. Dogs which survived the procedure were given tetracycline i.v. the next day and sacrificed 1 hour later by an overdose of pentobarbital sodium. The hearts were removed and the left ventricle was sliced and examined first under ultraviolet light to localize the ischemic zone by noting the tetracycline fluorescence. The ventricular slices were next incubated in nitro blue tetrazolium which stains normal myocardial tissue, thus allowing one to quantitate the volume of infarcted myocardium by excising and weighing the nonstained and stained muscle separately. The untreated control group had an infarct volume of 23.8 +/- 3.2 g/100 g of left ventricle. The treated animals in groups A and B had respective infarct volumes of 2.3 +/- 0.8 g/100 g (P less than .001) and 7.0 +/- 3.3 g/100 g (P less than .025) of left ventricle. During the acute phase of ischemia and reperfusion, arrhythmias and alterations in the ST-segment, R-wave amplituted and development of pathologic Q-waves were more prominent in the untreated animals and almost totally absent in the treated animals. UM-272 produced a dose-dependent decrease in heart rate as well as a decrease in developed isometric tension. Pretreatment with UM-272 did not prevent the derangement of function in the ischemic zone nor did it permit a return of function upon reperfusion, even though it reduced the degree of cellular damage resulting from 60 minutes of regional ischemia. A possible mechanism for the protective ef

Topics: Animals; Blood Pressure; Cardiac Output; Coronary Circulation; Coronary Disease; Disease Models, Animal; Dogs; Electrocardiography; Heart Rate; Myocardial Contraction; Myocardial Infarction; Myocardium; Nitroblue Tetrazolium; Oxidoreductases; Propranolol; Tetracycline; Time Factors

Topics: Acute Disease; Asia, Western; Blindness; Conjunctivitis; Diptera; Disease Models, Animal; Doxycycline; Endophthalmitis; Eyelid Diseases; Humans; Insect Control; Tetracycline; Trachoma

Iodine-131-tetracycline (131I-TET) was prepared by allowing tetracycline hydrochloride to react with radioiodide in acidic methanol (labeling efficiency greater than 85%). This preparation was found to be stable at--4 degrees C for at least 72 hr. Some minimal in vivo breakdown did occur. The 131I-TET, 67Ga, and several 99mTc compounds were studied in a rat hepatoma model. The incorporation of the radiopharmaceuticals into the tumor occurred rapidly, with peak levels at 0.5 and 24 hr after injection for 131I-TET and 67Ga, respectively. The clearnace of the radiopharmaceutical from nonviable tumor was slower than for viable tumor, and by 72 hr after injection the greatest concentration of radioactivity appeared in the nonviable fraction. All normal tissues showed faster clearance than did tumor tissue, regardless of viability. Decreasing the quantity of 131I-TET injected increased the percent of uptake in the nonviable tumor tissue but had no effect on the viable tumor uptake. Of the 99mTc compounds studied, the phosphates developed the highest tumor-to-background ratios. Unfortunately these ratios were not as high as those achieved for 67Ga or 131I-TET.

Topics: Animals; Disease Models, Animal; Gallium; Gallium Radioisotopes; Iodine Radioisotopes; Isotope Labeling; Liver Neoplasms; Neoplasm Transplantation; Neoplasms; Neoplasms, Experimental; Phosphates; Potassium Iodide; Radionuclide Imaging; Rats; Sugar Acids; Technetium; Tetracycline

A technique for inducing pneumococcal meningitis in mice and a description of the histopathologic changes that accompany this experimentally produced disease are provided in the present report. This infection of mice was investigated to determine whether it could serve as a suitable model for detecting agents that have potential therapeutic utility in bacterial meningitis in man. 21 antibiotics, belonging to six major classes were evaluated for efficacy in the experimental infection. The three most active agents proved to be amoxicillin, cephaloridine, and chlortetracycline. Up to this time, amoxicillin has not been commercially available as an injectable dosage form. However, in view of the compound's outstanding efficacy in the present experiments, it would be desirable to investigate its effectiveness in the naturally occurring disease in man.

Topics: Animals; Anti-Bacterial Agents; Cephalosporins; Cerebellum; Cerebral Cortex; Chloramphenicol; Chlortetracycline; Demeclocycline; Disease Models, Animal; Erythromycin; Lincomycin; Male; Meningitis, Pneumococcal; Mice; Penicillins; Rolitetracycline; Streptococcus pneumoniae; Tetracycline; Virulence

Topics: Animals; Disease Models, Animal; Female; Isotope Labeling; Muscles; Myocardial Infarction; Radionuclide Imaging; Rats; Technetium; Tetracycline

Dose-response relationships, biochemical mechanisms, and sex differences in the experimental fatty liver induced by tetracycline were studied in the intact rat and with the isolated perfused rat liver in vitro. In the intact male and female rat, no direct relationship was observed between dose of tetracycline and hepatic accumulation of triglyceride. With provision of adequate oleic acid as a substrate for the isolated perfused liver, a direct relationship was observed between dose of tetracycline and both accumulation of triglyceride in the liver and depression of output of triglyceride by livers from male and female rats. Marked differences were observed between female and male rats with regard to base line (control) hepatic concentration of triglyceride and output of triglyceride. Accumulation of hepatic triglyceride, as a per cent of control values, in response to graded doses of tetracycline, did not differ significantly between male, female and pregnant rat livers. However, livers from female, and especially pregnant female rats, were strikingly resistant to the effects of tetracycline on depression of output of triglyceride under these experimental conditions. These differences between the sexes could not be related to altered disposition of tetracycline or altered uptake of oleic acid. Depressed hepatic secretion of triglyceride accounted only for 30 to 50% of accumulated hepatic triglyceride, indicating that additional mechanisms must be involved in the production of the triglyceride-rich fatty liver in response to tetracycline.

Topics: Animals; Depression, Chemical; Disease Models, Animal; Dose-Response Relationship, Drug; Fatty Liver; Female; Liver; Male; Oleic Acids; Pregnancy; Rats; Sex Factors; Tetracycline; Triglycerides

An experimental animal model for testing antibiotics in vivo against Fusobacterium (Sphaerophorus) necrophorum has been developed. It incorporates the subcutaneous injection of the bacteria into mice followed by intraperitoneal administration of the antibiotic at 24, 48, 72, and 96 h. Mean effective dose values are based on the number of survivors 21 days after challenge. Tetracycline was the most effective drug tested, with a mean effective dose of 5.0 mg/kg, compared with mean effective dose values of 11.1 for clindamycin, 11.8 for penicillin-G, and 52.9 for lincomycin.

Topics: Animals; Anti-Bacterial Agents; Clindamycin; Disease Models, Animal; Fusobacterium; Fusobacterium Infections; Lincomycin; Male; Mice; Penicillins; Tetracycline

Eight grivet monkeys infected with Borrelia recurrentis received tetracycline (12.5mg/kg body weight) on the 3rd or 4th day of spirochetemia. Leukopenia, fever, hyperpnea, and tachycardia developed within 2 hours as spirochete counts fell to undetectable levels. These events closely simulated the crisis in human louse-borne relapsing fever in both timing and extent.

Topics: Animals; Blood; Borrelia; Disease Models, Animal; Female; Fever; Haplorhini; Heart Rate; Insect Vectors; Leukocyte Count; Leukocytes; Leukopenia; Male; Phthiraptera; Relapsing Fever; Respiration; Tachycardia; Tetracycline

Topics: Ampicillin; Animals; Blood Bactericidal Activity; Chloramphenicol; Chronic Disease; Disease Models, Animal; Escherichia coli; Escherichia coli Infections; Female; Nalidixic Acid; Penicillin Resistance; Pyelonephritis; Rats; Streptomycin; Sulfonamides; Tetracycline; Virulence

Topics: Ampicillin; Animals; Burns; Disease Models, Animal; Edetic Acid; Mice; Microbial Sensitivity Tests; Penicillin Resistance; Pseudomonas aeruginosa; Pseudomonas Infections; Tetracycline; Wound Infection

Topics: Animals; Anti-Bacterial Agents; Cephalothin; Chloramphenicol; Clostridium perfringens; Disease Models, Animal; Dogs; Gas Gangrene; Hyperbaric Oxygenation; Penicillins; Prognosis; Tetracycline

Topics: Animals; Candida albicans; Candidiasis; Disease Models, Animal; Female; Humans; Injections, Intradermal; Injections, Intraperitoneal; Injections, Intravenous; Injections, Subcutaneous; Male; Mice; Rabbits; Species Specificity; Tetracycline; Vagina

Topics: Animals; Candida albicans; Candidiasis; Disease Models, Animal; Injections, Intradermal; Injections, Intraperitoneal; Injections, Intravenous; Injections, Subcutaneous; Mice; Rabbits; Species Specificity; Tetracycline; Virulence

Topics: Animals; Arteries; Arthritis, Rheumatoid; Brain; Cerebral Arterial Diseases; Chickens; Disease Models, Animal; Gold; Mice; Mycoplasma; Mycoplasma Infections; Rats; Swine; Tetracycline; Turkeys

Topics: Animals; Cornea; Disease Models, Animal; Dysentery, Bacillary; Epithelial Cells; Escherichia coli; Evaluation Studies as Topic; Guinea Pigs; Injections, Intramuscular; Kanamycin; Keratoconjunctivitis; Ophthalmic Solutions; Rifampin; Shigella; Shigella flexneri; Streptomycin; Tetracycline

Topics: Animals; Antigens, Bacterial; Bacterial Vaccines; Bacteriological Techniques; Culture Media; Disease Models, Animal; Female; Haplorhini; Humans; Infant; Infant, Newborn; National Institutes of Health (U.S.); Penicillins; Pregnancy; Rabbits; Syphilis; Syphilis, Congenital; Tetracycline; Treponema; Treponema Immobilization Test; Treponema pallidum; United States

Topics: Ampicillin; Animals; Brucellosis; Cell Count; Complement Fixation Tests; Corynebacterium Infections; Disease Models, Animal; Drug Combinations; Drug Interactions; Evaluation Studies as Topic; Female; Hemagglutination Tests; Injections, Intraperitoneal; Mice; Organ Size; Propionibacterium acnes; Pyrimidines; Spleen; Sulfamethoxazole; Tetracycline; Trimethoprim

Topics: Amines; Animals; Disease Models, Animal; Femur Head; Lathyrism; Male; Microscopy, Fluorescence; Nitriles; Osteoporosis; Rats; Rats, Inbred Strains; Tetracycline

Topics: Animals; Bone Marrow; Dactinomycin; Disease Models, Animal; Humans; Hydrolases; Leukemia; Lincomycin; Mice; Mice, Inbred Strains; Mycoplasma; Mycoplasma Infections; Tetracycline

Topics: Animals; Animals, Zoo; Antibody Formation; Arthritis, Rheumatoid; Disease Models, Animal; gamma-Globulins; Hominidae; Injections, Intravenous; Male; Mycoplasma; Mycoplasma Infections; Pharynx; Synovial Membrane; Tetracycline

Topics: Animals; Cell Count; Disease Models, Animal; Escherichia coli Infections; Female; Kidney; Nalidixic Acid; Nitrofurantoin; Oxytetracycline; Pyelonephritis; Rats; Tetracycline; Urinary Tract Infections

Actinobolin, a known inhibitor of protein synthesis, has been shown not to interfere selectively with acid production or dextransucrase activity in a cariogenic streptococcus when the antibiotic is added to a concentration of 500 mug/ml. It has also been shown that actinobolin does not alter the total in vivo flora of the oral cavity of the rat when tested in a rat caries model system. A culture of cariogenic streptococci, adapted to in vitro growth in the presence of 1 mg of actinobolin per ml, has also been isolated.

Topics: Animals; Anti-Bacterial Agents; Bacteriological Techniques; Culture Media; Dental Caries; Dextrans; Diet; Disease Models, Animal; Drug Resistance, Microbial; Genetics, Microbial; Glucosyltransferases; Hydrogen-Ion Concentration; Male; Molar; Mutation; Rats; Rats, Inbred Strains; Streptococcus; Tetracycline; Time Factors

Topics: Abnormalities, Drug-Induced; Animals; Animals, Newborn; Disease Models, Animal; Female; Pregnancy; Rabbits; Spine; Tetracycline

Topics: Administration, Oral; Adrenal Cortex Hormones; Air Microbiology; Animals; Dexamethasone; Disease Models, Animal; Female; Germ-Free Life; Lung; Male; Pneumonia, Pneumocystis; Rats; Rats, Inbred Strains; Tetracycline; Time Factors

Topics: Ammonia; Animals; Anti-Bacterial Agents; Ascorbic Acid; Bacitracin; Chloramphenicol; Chlortetracycline; Demeclocycline; Depression, Chemical; Disease Models, Animal; Enzyme Repression; Erythromycin; Female; Hydroxamic Acids; In Vitro Techniques; Intestines; Kanamycin; Male; Neomycin; Niacinamide; Oxytetracycline; Penicillin G; Rats; Streptomycin; Sulfamethoxypyridazine; Sulfisoxazole; Sulfonamides; Tetracycline; Urease

Topics: Animals; Anti-Bacterial Agents; Clostridium Infections; Disease Models, Animal; Drug Synergism; Escherichia coli Infections; Gas Gangrene; Liver Extracts; Penicillin G Procaine; Proteus Infections; Rats; Staphylococcal Infections; Tetracycline

Topics: Animals; Burns; Chloramphenicol; Disease Models, Animal; Gentamicins; Mice; Mononuclear Phagocyte System; Penicillins; Phagocytosis; Plasma Substitutes; Pseudomonas aeruginosa; Pseudomonas Infections; Rats; Shock, Traumatic; Stimulation, Chemical; Tetracycline

Topics: Animals; Bartonella Infections; Chickens; Chlortetracycline; Disease Models, Animal; Oxytetracycline; Rolitetracycline; Tetracycline

Topics: Animals; Dentin; Disease Models, Animal; Incisor; Rats; Tetracycline; Tooth Calcification; Tooth Discoloration