cytochalasin-b and Disease-Models--Animal

Topics: Animals; Bronchi; Bronchitis; Calcium; Cilia; Colchicine; Cytochalasin B; Disease Models, Animal; Humans; Mucus; Organ Culture Techniques; Prostaglandins; Proteoglycans; Respiratory Physiological Phenomena; Sputum; Vasopressins

Traditional approaches to human and experimental teratology are briefly described, with roles of pathologists indicated. Some approaches to experimental teratology which pathologists might use are then described and illustrated. These include identification of subclasses of malformation types, study of the chronologic sequence of maldevelopment, study of embryo death, and examination of tumor-malformation relationships. The malformations used to illustrate these approaches are cleft palate, anencephaly, hydrocephalus, and intestinal atresia. The final section deals with general methodology in experimental teratology; a listing of books dealing with experimental teratology is included.

Topics: Abnormalities, Drug-Induced; Anencephaly; Animals; Chick Embryo; Cleft Palate; Congenital Abnormalities; Cytochalasin B; Disease Models, Animal; Female; Fetal Death; Histocytochemistry; Humans; Hydrocephalus; Intestinal Atresia; Mice; Microscopy, Electron; Pregnancy; Rabbits; Rats; Teratogens; Virus Diseases

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

The targeted delivery of therapeutics to sites of rheumatoid arthritis (RA) has been a long-standing challenge. Inspired by the intrinsic inflammation-targeting capacity of macrophages, a macrophage-derived microvesicle (MMV)-coated nanoparticle (MNP) was developed for targeting RA. The MMV was efficiently produced through a novel method. Cytochalasin B (CB) was applied to relax the interaction between the cytoskeleton and membrane of macrophages, thus stimulating MMV secretion. The proteomic profile of the MMV was analyzed by iTRAQ (isobaric tags for relative and absolute quantitation). The MMV membrane proteins were similar to those of macrophages, indicating that the MMV could exhibit bioactivity similar to that of RA-targeting macrophages. A poly(lactic- co-glycolic acid) (PLGA) nanoparticle was subsequently coated with MMV, and the inflammation-mediated targeting capacity of the MNP was evaluated both in vitro and in vivo. The in vitro binding of MNP to inflamed HUVECs was significantly stronger than that of the red blood cell membrane-coated nanoparticle (RNP). Compared with bare NP and RNP, MNP showed a significantly enhanced targeting effect in vivo in a collagen-induced arthritis (CIA) mouse model. The targeting mechanism was subsequently revealed according to the proteomic analysis, indicating that Mac-1 and CD44 contributed to the outstanding targeting effect of the MNP. A model drug, tacrolimus, was encapsulated in MNP (T-RNP) and significantly suppressed the progression of RA in mice. The present study demonstrates MMV as a promising and rich material, with which to mimic macrophages, and demonstrates that MNP is an efficient biomimetic vehicle for RA targeting and treatment.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Cytochalasin B; Disease Models, Animal; Erythrocytes; Gene Expression Regulation; Human Umbilical Vein Endothelial Cells; Humans; Hyaluronan Receptors; Macrophage-1 Antigen; Macrophages; Mice; Nanoparticles; Polyesters; Polylactic Acid-Polyglycolic Acid Copolymer; Proteomics; Tacrolimus

Recently, evidence indicated that the rapamycin-eluting stent which was used worldwide may contribute to an increased risk for thrombosis. On the contrary, other researchers found it was safe. Thus, it is necessary to clarify the effect of rapamycin on thrombosis and the corresponding mechanisms.. The effects of rapamycin in vivo were evaluated by modified deep vein thrombosis animal model. The platelets were from healthy volunteers and the platelet-endothelium (purchased from ATCC) adhesion in cultured endothelial cells was assessed. Membrane rufflings in endothelial cells were examined by confocal and electron microscope. Thrombus formation increased in rats that were injected with rapamycin. Electron microscope analysis exhibited microvilli on the rapamycin-treated endothelium in rats. Rapamycin enhanced membrane ruffling in human umbilical vein endothelial cells (HUVECs) and adhesion of platelets to HUVECs. The platelet-HUVECs adhesion was attenuated when cells were treated with cytochalacin B. Inhibition of autophagy by 3-methyladenine led to suppression of membrane ruffles in HUVECs and augmentation of platelet-endothelial adhesion.. In conclusion, we found that endothelial membrane remodeling induced by rapamycin is crucial for the adhesion of platelets to endothelial cells and thereby for thrombosis in vivo, and that the endothelial membrane remodeling is autophagy dependent.

Topics: Adenine; Animals; Autophagy; Blood Platelets; Cell Adhesion; Cell Membrane; Cytochalasin B; Disease Models, Animal; Human Umbilical Vein Endothelial Cells; Humans; Male; Rats; Rats, Sprague-Dawley; Sirolimus; Thrombosis

Nur77 is a potent proapoptotic member of the nuclear receptor superfamily that is expressed predominantly in brain tissue. It has been demonstrated that Nur77 mediates apoptosis in multiple organs. Nur77-mediated early brain injury (EBI) involves a conformational change in BCL-2 and triggers cytochrome C (cytoC) release resulting in cellular apoptosis. This study investigates whether Nur77 can promote cerebral cell apoptosis after experimentally induced subarachnoid hemorrhage (SAH) in rats. Sprague Dawley rats were randomly assigned to three groups: 1) untreated group, 2) treatment control group, and 3) SAH group. The experimental SAH group was divided into four subgroups, corresponding to 12 hr, 24 hr, 48 hr, and 72 hr after experimentally induced SAH. It remains unclear whether Nur77 can play an important role during EBI after SAH as a proapoptotic protein in cerebral cells. Cytosporone B (Csn-B) was used to demonstrate that Nur77 could be enriched and used to aggravate EBI after SAH. Rats treated with Csn-B were given an intraperitoneal injection (13 mg/kg) 30 min after experimentally induced SAH. We found that Nur77 promotes cerebral cell apoptosis by mediating EBI and triggering a conformational change in BCL-2, resulting in cytoC release. Nur77 activity, along with cerebral cell apoptosis, peaked at 24 hr after SAH onset. After induction of SAH, an injection of Csn-B, an agonist for Nur77, enhanced the expression and function of Nur77. In summary, we have demonstrated the proapoptotic effect of Nur77 within cerebral cells, an effect that can be further exacerbated with Csn-B stimulation.

Topics: Analysis of Variance; Animals; Apoptosis; Brain Edema; Brain Injuries; Cerebral Cortex; Cytochalasin B; Cytochalasins; Disease Models, Animal; Gene Expression Regulation; In Situ Nick-End Labeling; Male; Neurologic Examination; Nuclear Receptor Subfamily 4, Group A, Member 1; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; RNA, Messenger; Subarachnoid Hemorrhage; Time Factors

Somatic cell nuclear transfer in cats offers a useful tool for the generation of valuable research models. However, low birth rates after nuclear transfer hamper exploitation of the full potential of the technology. Poor embryo development after activation of the reconstructed oocytes seems to be responsible, at least in part, for the low efficiency. The objective of this study was to characterize the response of cat oocytes to various stimuli in order to fine-tune existing and possibly develop new activation methods for the generation of cat disease models by somatic cell nuclear transfer.. First, changes in the intracellular free calcium concentration [Ca2+]i in the oocytes induced by a number of artificial stimuli were characterized. The stimuli included electroporation, ethanol, ionomycin, thimerosal, strontium-chloride and sodium (Na+)-free medium. The potential of the most promising treatments (with or without subsequent incubation in the presence of cycloheximide and cytochalasin B) to stimulate oocyte activation and support development of the resultant parthenogenetic embryos was then evaluated. Finally, the most effective methods were selected to activate oocytes reconstructed during nuclear transfer with fibroblasts from mucopolysaccharidosis I- and alpha-mannosidosis-affected cats.. All treatments were able to elicit a [Ca2+]i elevation in the ooplasm with various characteristics. Pronuclear formation and development up to the blastocyst stage was most efficiently triggered by electroporation (60.5 +/- 2.9 and 11.5 +/- 1.7%) and the combined thimerosal/DTT treatment (67.7 +/- 1.8 and 10.6 +/- 1.9%); incubation of the stimulated oocytes with cycloheximide and cytochalasin B had a positive effect on embryo development. When these two methods were used to activate oocytes reconstructed during nuclear transfer, up to 84.9% of the reconstructed oocytes cleaved. When the 2 to 4-cell embryos (a total of 220) were transferred into 19 recipient females, 4 animals became pregnant. All of the fetuses developed from oocytes activated by electroporation followed by cycloheximide and cytochalasin B incubation; no fetal development was detected as a result of thimerosal/DTT activation. Although heartbeats were detected in two of the cloned fetuses, no term development occurred.. Electroporation proved to be the most effective method for the activation of cat oocytes reconstructed by nuclear transfer. The combined thimerosal/DTT treatment followed by cycloheximide and cytochalasin B incubation triggered development effectively to the blastocyst stage; whether it is a viable option to stimulate term development of cloned cat embryos needs further investigations.

Topics: alpha-Mannosidosis; Animals; Calcium; Cat Diseases; Cats; Cycloheximide; Cytochalasin B; Disease Models, Animal; Electroporation; Embryo Culture Techniques; Embryonic Development; Female; Fibroblasts; Mucopolysaccharidosis I; Nuclear Transfer Techniques; Oocytes; Parthenogenesis; Pregnancy; Preservatives, Pharmaceutical; Protein Synthesis Inhibitors; Stimulation, Chemical; Thimerosal

A number of experimental studies have shown that increasing glucose use or decreasing accumulation of long-chain acyl carnitines (LCAC) protect ischemic hearts.. To evaluate the relative importance of these two strategies in protecting ischemic myocardium, isolated rat hearts (n = 6 in each group) were paced at 300 bpm and subjected to 50 min of low-flow ischemia followed by 60 min of reperfusion. Buffer contained 0.4 m mol/l albumin, 0.4 m mol/l palmitate, and 70 mU/l insulin, and either normal glucose (5 m mol/l) (CON), high glucose (10 m mol/l total) (HG, known to increase glucose use), 5 m mol/l glucose and niacin (10 micromol/l) (NIA, known to increase glucose use and decrease LCAC) or carnitine (10 m mol/l) (CAR, known to increase glucose use and decrease LCAC). Separate groups of hearts were perfused in the presence of 10 micromol/l cytochalasin-B (CB), an inhibitor of insulin-sensitive glucose transporters.. Ischemic injury, as assessed by creatine kinase (CK) release was diminished by an average of 50% in HG, NIA, and CAR hearts, and the percentage recovery of left ventricular (LV) function with reperfusion was enhanced by approximately 20% compared with CON hearts (P < 0.05 for each comparison). Cytochalasin-B abolished all of the salutary effects. Long-chain acyl carnitines levels were higher in HG hearts compared with NIA- and CAR-treated hearts ( P < 0.05), but ischemic protection and functional recovery was greater in HG hearts.. The data support the adjunctive use of agents that promote glucose uptake during ischemia and suggest that increasing glucose use is more important than decreasing LCAC in the protection against ischemic injury or in the recovery of contractile function.

Topics: Animals; Carnitine; Creatine Kinase; Cytochalasin B; Disease Models, Animal; Glucose; Models, Cardiovascular; Myocardial Contraction; Myocardial Ischemia; Myocardial Reperfusion Injury; Niacin; Oxygen Consumption; Rats; Recovery of Function; Stroke Volume; Vasodilator Agents; Ventricular Pressure

D-mannoheptulose is apparently transported into cells mainly at the intervention of GLUT-2 and hence was recently proposed as a tool to label preferentially insulin-producing beta-cells in the pancreatic gland. The validity of such a proposal was investigated in the present study conducted in isolated perfused pancreatic glands from control and streptozotocin-induced diabetic rats. After a 30-min equilibration period, D-[(3)H]mannoheptulose (0.1 mM) and [U-(14)C]sucrose (0.5 mM) were infused for 15 min in the presence of 30 mM D-glucose. The pancreatic glands were then perfused for 10 min with a nonradioactive medium during and after administration of cytochalasin B (0.02 mM). Under these experimental conditions, the intracellular distribution space of D-[(3)H]mannoheptulose averaged 5.42 +/- 0.75 nl/mg in control animals, whereas it failed to be significantly different from zero in the streptozotocin rats. The present procedure may thus allow the assessment of the relative contribution of islet beta-cells to the total mass of the pancreatic gland.

Topics: Animals; Carbon Radioisotopes; Cell Count; Cytochalasin B; Diabetes Mellitus, Experimental; Disease Models, Animal; Glucose; In Vitro Techniques; Insulin; Insulin Secretion; Intracellular Fluid; Islets of Langerhans; Male; Mannoheptulose; Organ Size; Pancreas; Perfusion; Rats; Rats, Wistar; Reproducibility of Results; Streptozocin; Sucrose; Tritium

Expression of beta 1 integrins was studied in vitro as articular chondrocytes reestablished a matrix in culture and in situ in a nonhuman primate model of osteoarthritis in order to investigate a potential role for integrins in mediating cell-extracellular matrix interactions in cartilage. Chondrocytes were found to express alpha 1 beta 1, alpha 3 beta 1, and alpha 5 beta 1 integrins both in vitro and in situ. Cell surface expression of beta 1 integrins increased as chondrocytes were maintained in cultured from 3 to 7 days. Increased beta 1 integrin expression was also observed in osteoarthritic cartilage compared with normal cartilage. The greatest relative increase in both systems was noted for the alpha 1 beta 1 integrin. The increase in chondrocyte beta 1 integrin expression in vitro was noted in both monolayer and alginate cultures and occurred prior to detectable changes in the differentiated phenotype of the chondrocyte. Disruption of the cytoskeleton with the drug dihydrocytochalasin B inhibited the cell culture induced increase in integrin expression, while treatment of cultured cells with TGF-beta resulted in increased expression of the alpha 5 beta 1 integrin. The modulation of beta 1 integrin expression noted in vitro and in situ indicates that chondrocytes are capable of regulated expression of beta 1 integrins and suggests that beta 1 integrins may play an important role in mediating chondrocyte-extracellular matrix interactions in cartilage.

Topics: Animals; Ascorbic Acid; Base Sequence; Cartilage, Articular; Cattle; Cell Adhesion; Cell Membrane; Cells, Cultured; Cytochalasin B; Cytoskeleton; Disease Models, Animal; DNA Primers; Extracellular Matrix; Humans; Integrin beta1; Integrins; Lymphotoxin-alpha; Macaca fascicularis; Molecular Sequence Data; Osteoarthritis; RNA, Messenger

Haemophilus ducreyi is a sexually transmitted pathogen that causes genital ulcers and inguinal adenopathy. Because chancroidal ulcers are most commonly located on the foreskins of uncircumcised males, we utilized human foreskin epithelial cells (HFECs) to investigate the initial interaction of H. ducreyi with its host. The eight different strains of H. ducreyi that were studied varied in their abilities to attach to these epithelial cells, with six strains consistently attaching to > or = 90% of HFECs and two strains attaching to < 25% of HFECs. The strains with low levels of adherence also failed to exhibit chaining in broth culture and were avirulent in the rabbit model, suggesting that virulence in this model and attachment may be linked. The most adherent strain, LA228R, was further evaluated for its ability to invade HFECs and HEp-2 cells. Scanning electron microscopy and transmission electron microscopy of HFECs after interaction with LA228R produced images consistent with attachment, ingestion into vesicles, and escape from the vesicles into the cytoplasm. In addition, the gentamicin protection assay and inhibition of invasion by cytochalasin B and D indicated that LA228R was able to invade both HFECs and HEp-2 cells. Further examination of the mechanisms involved in the adherence and invasion of H. ducreyi into epithelial cells and their correlation with virulence will provide a better understanding of the pathogenesis of the disease caused by this important pathogen.

Topics: Animals; Bacterial Adhesion; Cells, Cultured; Chancroid; Cytochalasin B; Cytochalasin D; Disease Models, Animal; Epithelial Cells; Epithelium; Gentamicins; Haemophilus ducreyi; Humans; Male; Penis; Rabbits; Skin; Virulence

Guinea pigs develop a lethal pneumonia after intratracheal infection with Legionella micdadei, and the lung displays pathological changes similar to those observed in humans. To investigate the role of the resident alveolar macrophage in the pathogenesis of L. micdadei pneumonia, guinea pig alveolar macrophages obtained by bronchoalveolar lavage were cultured in vitro and infected with L. micdadei. In the absence of opsonins L. micdadei was phagocytized by, and multiplied within, alveolar macrophages with greater than a 100-fold increase in cell-associated colony forming units over 20 h. L. micdadei opsonized with complement or antibody multiplied within alveolar macrophages at the same rate as unopsonized bacteria. Guinea pigs which were treated with antimicrobials after infection with L. micdadei and recovered from the pneumonia were immune to challenge with an otherwise lethal inoculum of L. micdadei. However, the growth curve of both unopsonized and opsonized L. micdadei in the alveolar macrophages from immune animals was essentially identical to that in macrophages from susceptible animals. Thus, the resident alveolar macrophage is not capable of limiting the growth of Legionella. Rather, the alveolar macrophages appear to be the primary site of Legionella multiplication within the lung. Although alveolar macrophages may participate in other aspects of pulmonary immunity to the legionellae, these data indicate that the alveolar macrophage alone does not act as an effector cell in cell-mediated immunity to Legionella.

Topics: Animals; Bacterial Adhesion; Cells, Cultured; Cytochalasin B; Disease Models, Animal; Guinea Pigs; Legionella; Legionellosis; Macrophages; Phagocytosis

We have tested the idea that the circulating plasma insulin level plays an important role in the long-term regulation, or maintenance, of the cellular glucose transport system, distinct from insulin's ability to acutely accelerate glucose transport. To study this hypothesis, groups of rats were made either hyperinsulinemic or hypoinsulinemic by daily insulin injections or Streptozotocin treatment, respectively. Different levels of hypoinsulinemia were produced by using different doses of Streptozotocin (40 and 55 mg/kg). Isolated adipocytes were prepared from each animal and glucose transport was assessed by measuring the initial rates of uptake of the nonmetabolyzable hexose 2-deoxy glucose. In cells from control animals, the Vmax of in vitro adipocyte glucose transport was 7.1 +/- 0.7 nmole/min/10(6) cells in the basal state and 22.9 +/- 0.9 nmole/min/10(6) cells in the presence of a maximally effective insulin concentration (25 ng/ml) in the buffer. In cells from the experimentally hyperinsulinemic animals, these Vmax values were increased to 11.7 +/- 0.8 and 44.2 +/- 1.1 nmole/min/10(6) cells. Using adipocytes from both groups of Streptozotocin treated (high dose, 55 mg/kg, low dose, 40 mg/kg) insulin deficient diabetic animals, Vmax values were found to be progressively decreased. Thus, in the low dose group, basal and insulin stimulated Vmax values were 1.6 +/- 0.5 and 5.7 +/- 0.7 nmole/min/10(6) cells, as compared to values of 0.9 +/- 0.2 and 1.7 +/- 0.6 in the high dose group. Furthermore, when hyperinsulinemia was induced by feeding rats high carbohydrate diets for 10 days, adipocyte glucose transport Vmax increased 50%. In contrast, when hypoinsulinemia was achieved by fasting rats for 72 hr, transport Vmax decreased by 50%. The apparent Km for 2-deoxy glucose uptake was the same under all conditions. In conclusion, assuming that the Vmax of transport is some function of the number of glucose transport carriers per cell, then these results support the hypothesis that in addition to acute acceleration of glucose transport, insulin is also an important long-term regulator of the number of available adipocyte glucose transport carriers.

Topics: Adipose Tissue; Animals; Biological Transport, Active; Blood Glucose; Cytochalasin B; Deoxyglucose; Diabetes Mellitus, Experimental; Disease Models, Animal; Glucose; Hyperinsulinism; Insulin; Kinetics; Male; Rats

Topics: Animals; Antigens; Arginine; Cyclic AMP; Cytochalasin B; Diabetes Mellitus; Disease Models, Animal; Dose-Response Relationship, Drug; Glucose; In Vitro Techniques; Insulin; Insulin Secretion; Iodine Radioisotopes; Islets of Langerhans; Male; Mice; Obesity; Radioimmunoassay; Rats; Secretory Rate; Theophylline; Time Factors; Vincristine