lipid-a and Bacterial-Infections

Unprecedented community containment measures were taken following the recent outbreak of COVID-19 in Italy. The aim of the study was to explore the self-reported future compliance of citizens with such measures and its relationship with potentially impactful psychological variables.. An online survey was completed by 931 people (18-76 years) distributed across the Italian territory. In addition to demographics, five dimensions were measured: self-reported compliance with containment measures over time (today, at 7, 14, 30, 60, 90, and 180 days from now) at three hypothetical risk levels (10, 50, 90% of likelihood of contracting the COVID-19), perceived risk, generalized anxiety, intolerance of uncertainty, and relevance of several psychological needs whose satisfaction is currently precluded.. The duration of containment measures plays a crucial role in tackling the spread of the disease as people will be less compliant over time. Psychological needs of citizens impacting on the compliance should be taken into account when planning an easing of the lockdown, along with interventions for protecting vulnerable groups from mental distress.. La apendicitis aguda (AA) es la urgencia quirúrgica abdominal más frecuente. No encontramos estudios específicos que evalúen el impacto de la pandemia causada por el coronavirus 2 (SARS-Cov-2) sobre la AA y su tratamiento quirúrgico. Analizamos la influencia de esta nueva patología sobre la AA.. Estudio observacional retrospectivo en pacientes intervenidos por AA desde enero hasta abril de 2020. Fueron clasificados según el momento de la apendicectomía, antes de la declaración del estado de alarma (Pre-COVID19) y después de la declaración del estado de alarma (Post-COVID19) en España. Se evaluaron variables demográficas, duración de la sintomatología, tipo de apendicitis, tiempo quirúrgico, estancia hospitalaria y complicaciones postoperatorias.. La pandemia por SARS-Cov-2 influye en el momento de diagnóstico de la apendicitis, así como en su grado de evolución y estancia hospitalaria. La peritonitis fue lo más frecuentemente observado. Una sospecha y orientación clínica más temprana, es necesaria para evitar un manejo inadecuado de este trastorno quirúrgico común.. The primary outcome is improvement in PaO. Findings will provide timely information on the safety, efficacy, and optimal dosing of t-PA to treat moderate/severe COVID-19-induced ARDS, which can be rapidly adapted to a phase III trial (NCT04357730; FDA IND 149634).. None.. The gut barrier is crucial in cirrhosis in preventing infection-causing bacteria that normally live in the gut from accessing the liver and other organs via the bloodstream. Herein, we characterised gut inflammation by measuring different markers in stool samples from patients at different stages of cirrhosis and comparing this to healthy people. These markers, when compared with equivalent markers usually measured in blood, were found to be very different in pattern and absolute levels, suggesting that there is significant gut inflammation in cirrhosis related to different immune system pathways to that seen outside of the gut. This provides new insights into gut-specific immune disturbances that predispose to complications of cirrhosis, and emphasises that a better understanding of the gut-liver axis is necessary to develop better targeted therapies.. La surveillance de l’intervalle QT a suscité beaucoup d’intérêt durant la pandémie de la COVID-19 en raison de l’utilisation de médicaments prolongeant l’intervalle QT et les préoccupations quant à la transmission virale par les électrocardiogrammes (ECG) en série. Nous avons posé l’hypothèse que la surveillance en continu de l’intervalle QT par télémétrie était associée à une meilleure détection des épisodes de prolongation de l’intervalle QT.. Nous avons introduit la télémétrie cardiaque en continu (TCC) à l’aide d’un algorithme de surveillance automatisée de l’intervalle QT dans nos unités de COVID-19. Les mesures automatisées quotidiennes de l’intervalle QT corrigé (auto-QTc) en fonction de la fréquence cardiaque maximale ont été enregistrées. Nous avons comparé la proportion des épisodes de prolongation marquée de l’intervalle QTc (QTc long), définie par un intervalle QTc ≥ 500 ms, chez les patients montrant une suspicion de COVID-19 ou ayant la COVID-19 qui avaient été admis avant et après la mise en place de la TCC (groupe témoin. La surveillance en continu de l’intervalle QT est supérieure à la norme de soins dans la détection des épisodes de QTc long et exige peu d’ECG. La réponse clinique aux épisodes de QTc long est sous-optimale.. Exposure to a model wildfire air pollution source modifies cardiovascular responses to HC challenge, suggesting air pollution sensitizes the body to systemic triggers.. Though the majority of HIV-infected adults who were on HAART had shown viral suppression, the rate of suppression was sub-optimal according to the UNAIDS 90-90-90 target to help end the AIDS pandemic by 2020. Nonetheless, the rate of immunological recovery in the study cohort was low. Hence, early initiation of HAART should be strengthened to achieve good virological suppression and immunological recovery.. Dust in Egyptian laying hen houses contains high concentrations of microorganisms and endotoxins, which might impair the health of birds and farmers when inhaled. Furthermore, laying hens in Egypt seem to be a reservoir for ESBL-producing Enterobacteriaceae. Thus, farmers are at risk of exposure to ESBL-producing bacteria, and colonized hens might transmit these bacteria into the food chain.. The lack of significant differences in the absolute changes and relative ratios of injury and repair biomarkers by contrast-associated AKI status suggests that the majority of mild contrast-associated AKI cases may be driven by hemodynamic changes at the kidney.. Most comparisons for different outcomes are based on very few studies, mostly low-powered, with an overall low CoE. Thus, the available evidence is considered insufficient to either support or refute CH effectiveness or to recommend one ICM over another. Therefore, further well-designed, larger RCTs are required.. PROSPERO database Identifier: CRD42016041953.. Untouched root canal at cross-section perimeter, the Hero 642 system showed 41.44% ± 5.62% and Reciproc R40 58.67% ± 12.39% without contact with instruments. Regarding the untouched area, Hero 642 system showed 22.78% ± 6.42% and Reciproc R40 34.35% ± 8.52%. Neither instrument achieved complete cross-sectional root canal debridement. Hero 642 system rotary taper 0.02 instruments achieved significant greater wall contact perimeter and area compared to reciprocate the Reciproc R40 taper 0.06 instrument.. Hero 642 achieved higher wall contact perimeter and area but, regardless of instrument size and taper, vital pulp during. The functional properties of the main mechanisms involved in the control of muscle Ca. This study showed that the anti-inflammatory effect of the iron-responsive product DHA in arthritis can be monitored by an iron-like radioactive tracer (. Attenuated vascular reactivity during pregnancy suggests that the systemic vasodilatory state partially depletes nitric oxide bioavailability. Preliminary data support the potential for MRI to identify vascular dysfunction in vivo that underlies PE. Level of Evidence 2 Technical Efficacy Stage 1 J. MAGN. RESON. IMAGING 2021;53:447-455.. La evaluación de riesgo es importante para predecir los resultados postoperatorios en pacientes con cáncer gastroesofágico. Este estudio de cohortes tuvo como objetivo evaluar los cambios en la composición corporal durante la quimioterapia neoadyuvante e investigar su asociación con complicaciones postoperatorias. MÉTODOS: Los pacientes consecutivos con cáncer gastroesofágico sometidos a quimioterapia neoadyuvante y cirugía con intención curativa entre 2016 y 2019, identificados a partir de una base de datos específica, se incluyeron en el estudio. Se utilizaron las imágenes de tomografía computarizada, antes y después de la quimioterapia neoadyuvante, para evaluar el índice de masa muscular esquelética, la sarcopenia y el índice de grasa visceral y subcutánea.. In this in vitro premature infant lung model, HF oscillation of BCPAP was associated with improved CO. Our results showed that HPC significantly promotes neurogenesis after MCAO and ameliorates neuronal injury.. Inflammatory markers are highly related to signs of systemic hypoperfusion in CS. Moreover, high PCT and IL-6 levels are associated with poor prognosis.. These findings indicate that Tetrapleura tetraptera fruit has a protective potential against stroke through modulation of redox and electrolyte imbalances, and attenuation of neurotransmitter dysregulation and other neurochemical dysfunctions. Tetrapleura tetraptera fruit could be a promising source for the discovery of bioactives for stroke therapy.

Topics: 3T3-L1 Cells; A Kinase Anchor Proteins; Acetates; Achilles Tendon; Acute Kidney Injury; Acute Pain; Acyclic Monoterpenes; Adenine Nucleotides; Adhesins, Escherichia coli; Adipocytes; Adipocytes, Brown; Adipogenesis; Administration, Inhalation; Administration, Oral; Adrenal Cortex Hormones; Adsorption; Adult; Aeromonas hydrophila; Africa; Aged; Aged, 80 and over; Agrobacterium tumefaciens; Air; Air Pollutants; Air Pollution; Air Pollution, Indoor; Algorithms; Alkaloids; Alkynes; Allosteric Regulation; Amines; Amino Acid Sequence; Amino Acids; Amino Acids, Branched-Chain; Aminoisobutyric Acids; Aminopyridines; Amyotrophic Lateral Sclerosis; Anaerobic Threshold; Angiography; Angiotensin II Type 1 Receptor Blockers; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Animal Distribution; Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Ankle Joint; Anti-Bacterial Agents; Anti-HIV Agents; Anti-Inflammatory Agents; Antibodies, Bacterial; Antifungal Agents; Antimalarials; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Antioxidants; Antiretroviral Therapy, Highly Active; Antiviral Agents; Aotidae; Apelin; Apoptosis; Arabidopsis Proteins; Argentina; Arginine; Artemisinins; Arthritis, Experimental; Arthritis, Rheumatoid; Arthroscopy; Aspergillus; Aspergillus niger; Asteraceae; Asthma; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; Auditory Cortex; Autoantibodies; Autophagy; Bacteria; Bacterial Infections; Bacterial Proteins; Bacterial Typing Techniques; Base Composition; Base Sequence; Basketball; Beclin-1; Benzhydryl Compounds; Benzimidazoles; Benzo(a)pyrene; Benzofurans; Benzoxazines; Bereavement; beta Catenin; beta-Lactamase Inhibitors; beta-Lactamases; beta-Lactams; Betacoronavirus; Betaine; Binding Sites; Biofilms; Biological Assay; Biological Availability; Biological Evolution; Biomarkers; Biomechanical Phenomena; Biopolymers; Biopsy; Bismuth; Blood Glucose; Blood Platelets; Blood Pressure; Body Composition; Body Weight; Bone Marrow; Bone Marrow Cells; Bone Regeneration; Boron; Botrytis; Brain Ischemia; Brain Neoplasms; Brain-Derived Neurotrophic Factor; Brazil; Breast Neoplasms; Breath Tests; Bronchoalveolar Lavage Fluid; Burkholderia; C-Reactive Protein; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Calcification, Physiologic; Calcium; Calcium Signaling; Calorimetry, Differential Scanning; Cameroon; Camptothecin; Candida; Candida albicans; Capillaries; Carbapenem-Resistant Enterobacteriaceae; Carbapenems; Carbohydrate Conformation; Carbon; Carbon Dioxide; Carbon Isotopes; Carcinoma, Ovarian Epithelial; Cardiac Output; Cardiomyopathy, Hypertrophic; Cardiotonic Agents; Cardiovascular Diseases; Caregivers; Carps; Case-Control Studies; Catalase; Catalysis; Cats; CD4 Lymphocyte Count; Cell Culture Techniques; Cell Differentiation; Cell Line, Tumor; Cell Membrane; Cell Movement; Cell Proliferation; Cell Survival; Cells, Cultured; Cellulose; Centrosome; Ceratopogonidae; Chickens; Child; China; Cholera Toxin; Choline; Cholinesterases; Chromatography, High Pressure Liquid; Chromatography, Liquid; Chromatography, Micellar Electrokinetic Capillary; Chromatography, Reverse-Phase; Chronic Disease; Cinnamates; Cities; Citrates; Climate Change; Clinical Trials, Phase III as Topic; Coal; Coal Mining; Cohort Studies; Coinfection; Colchicine; Colony Count, Microbial; Colorectal Neoplasms; Coloring Agents; Common Cold; Complement Factor H; Computational Biology; Computer Simulation; Continuous Positive Airway Pressure; Contrast Media; Coordination Complexes; Coronary Artery Bypass; Coronavirus 3C Proteases; Coronavirus Infections; Coronavirus Protease Inhibitors; Corynebacterium glutamicum; Cosmetics; COVID-19; Creatinine; Cross-Sectional Studies; Crotonates; Crystallography, X-Ray; Cues; Culicidae; Culture Media; Curcuma; Cyclopentanes; Cyclopropanes; Cymbopogon; Cystine; Cytochrome P-450 CYP2B6; Cytochrome P-450 CYP2C19; Cytochrome P-450 CYP2C19 Inhibitors; Cytokines; Databases, Genetic; Death; Dendritic Cells; Density Functional Theory; Depsides; Diabetes Mellitus, Type 2; Diamond; Diarylheptanoids; Dibenzofurans; Dibenzofurans, Polychlorinated; Diclofenac; Diet; Dietary Carbohydrates; Dietary Supplements; Diffusion Magnetic Resonance Imaging; Dioxins; Diphenylamine; Disease Outbreaks; Disease Susceptibility; Disulfides; Dithiothreitol; Dizocilpine Maleate; DNA Methylation; DNA-Binding Proteins; DNA, Bacterial; Dogs; Dose-Response Relationship, Drug; Double-Blind Method; Doublecortin Protein; Drosophila melanogaster; Droughts; Drug Carriers; Drug Combinations; Drug Delivery Systems; Drug Liberation; Drug Resistance; Drug Resistance, Bacterial; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Dust; Dynactin Complex; Dysferlin; Echo-Planar Imaging; Echocardiography; Edaravone; Egypt; Elasticity; Electrodes; Electrolytes; Emodin; Emtricitabine; Endometriosis; Endothelium, Vascular; Endotoxins; Energy Metabolism; Energy Transfer; 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Plant Oils; Plants, Medicinal; Plasmodium berghei; Plasmodium falciparum; Platelet Activation; Platelet Function Tests; Pneumonia, Viral; Poaceae; Pogostemon; Poloxamer; Poly I; Poly(ADP-ribose) Polymerase Inhibitors; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Polycyclic Compounds; Polyethylene Glycols; Polylysine; Polymorphism, Genetic; Polymorphism, Single Nucleotide; Population Dynamics; Portasystemic Shunt, Transjugular Intrahepatic; Positron Emission Tomography Computed Tomography; Postoperative Complications; Postprandial Period; Potassium Cyanide; Predictive Value of Tests; Prefrontal Cortex; Pregnancy; Prepulse Inhibition; Prevalence; Procalcitonin; Prodrugs; Prognosis; Progression-Free Survival; Proline; Proof of Concept Study; Prospective Studies; Protein Binding; Protein Conformation; Protein Domains; Protein Folding; Protein Multimerization; Protein Sorting Signals; Protein Structure, Secondary; Proton Pump Inhibitors; Protozoan Proteins; Psychometrics; Pulse Wave Analysis; Pyridines; Pyrrolidines; Quality of Life; Quantum Dots; Quinoxalines; Quorum Sensing; Radiopharmaceuticals; Rain; Random Allocation; Randomized Controlled Trials as Topic; Rats; Rats, Sprague-Dawley; Rats, Wistar; RAW 264.7 Cells; Reactive Oxygen Species; Receptor, Angiotensin, Type 1; Receptor, PAR-1; Receptors, CXCR4; Receptors, Estrogen; Receptors, Glucocorticoid; Receptors, Interleukin-1; Receptors, Interleukin-17; Receptors, Notch; Recombinant Fusion Proteins; Recombinant Proteins; Reducing Agents; Reflex, Startle; Regional Blood Flow; Regression Analysis; Reperfusion Injury; Reproducibility of Results; Republic of Korea; Respiratory Tract Diseases; Retrospective Studies; Reverse Transcriptase Inhibitors; Rhinitis, Allergic; Risk Assessment; Risk Factors; Rituximab; RNA, Messenger; RNA, Ribosomal, 16S; ROC Curve; Rosmarinic Acid; Running; Ruthenium; Rutin; Sarcolemma; Sarcoma; Sarcopenia; Sarcoplasmic Reticulum; SARS-CoV-2; Scavenger Receptors, Class A; Schools; Seasons; Seeds; Sequence Analysis, DNA; 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The process of natural selection favours germ-line gene segments that encode CDRs that have the ability to recognize a range of structurally related antigens. This presents an immunological advantage to the host, as it can confer protection against a common pathogen and still cope with new or changing antigens. Cross-reactive and polyspecific antibodies also play a central role in autoimmune responses, and a link has been shown to exist between auto-reactive B cells and certain bacterial infections. Bacterial DNA, lipids, and carbohydrates have been implicated in the progression of autoimmune diseases such as systemic lupus erythematosus. As well, reports of anti-lipid A antibody polyspecificity towards single-stranded DNA together with the observed sequence homology amongst isolated auto- and anti-lipid A antibodies has prompted further study of this phenomenon. Though the lipid A epitope appears cryptic during Gram-negative bacterial infection, there have been several reported instances of lipid A-specific antibodies isolated from human sera, some of which have exhibited polyspecificity for single stranded DNA. In such cases, the breakdown of negative selection through polyspecificity can have the unfortunate consequence of autoimmune disease. This review summarizes current knowledge regarding such antibodies and emphasizes the features of S1-15, A6, and S55-5, anti-lipid A antibodies whose structures were recently determined by X-ray crystallography.

Topics: Animals; Antibody Specificity; Autoantibodies; Autoimmune Diseases; Autoimmunity; B-Lymphocytes; Bacterial Infections; DNA, Single-Stranded; Humans; Lipid A; Models, Molecular; Protein Conformation; Structure-Activity Relationship

Lipopolysaccharide or LPS is localized to the outer leaflet of the outer membrane and serves as the major surface component of the bacterial cell envelope. This remarkable glycolipid is essential for virtually all Gram-negative organisms and represents one of the conserved microbial structures responsible for activation of the innate immune system. For these reasons, the structure, function, and biosynthesis of LPS has been an area of intense research. The LPS of a number of bacteria is composed of three distinct regions--lipid A, a short core oligosaccharide, and the O-antigen polysaccharide. The lipid A domain, also known as endotoxin, anchors the molecule in the outer membrane and is the bioactive component recognized by TLR4 during human infection. Overall, the biochemical synthesis of lipid A is a highly conserved process; however, investigation of the lipid A structures of various organisms shows an impressive amount of diversity. These differences can be attributed to the action of latent enzymes that modify the canonical lipid A molecule. Variation of the lipid A domain of LPS serves as one strategy utilized by Gram-negative bacteria to promote survival by providing resistance to components of the innate immune system and helping to evade recognition by TLR4. This review summarizes the biochemical machinery required for the production of diverse lipid A structures of human pathogens and how structural modification of endotoxin impacts pathogenesis.

Topics: Animals; Bacterial Infections; Cell Wall; Gram-Negative Bacteria; Humans; Lipid A; Lipopolysaccharides; Molecular Structure; O Antigens; Oligosaccharides; Toll-Like Receptor 4

Innate immune receptors recognize microorganism-specific motifs. One such receptor-ligand complex is formed between the mammalian Toll-like receptor 4 (TLR4)-MD2-CD14 complex and bacterial lipopolysaccharide (LPS). Recent research indicates that there is significant phylogenetic and individual diversity in TLR4-mediated responses. In addition, the diversity of LPS structures and the differential recognition of these structures by TLR4 have been associated with several bacterial diseases. This review will examine the hypothesis that the variability of bacterial ligands such as LPS and their innate immune receptors is an important factor in determining the outcome of infectious disease.

Topics: Animals; Antigens, Surface; Bacterial Infections; Carrier Proteins; Disease Progression; Disease Susceptibility; Humans; Immunity, Innate; Lipid A; Lipopolysaccharide Receptors; Lipopolysaccharides; Lymphocyte Antigen 96; Membrane Glycoproteins; Molecular Structure; Receptors, Cell Surface; Signal Transduction; Species Specificity; Toll-Like Receptor 4; Toll-Like Receptors

Animals that cannot sense endotoxin may die if they are infected by Gram-negative bacteria. Animals that sense endotoxin and respond too vigorously may also die, victims of their own inflammatory reactions. The outcome of Gram-negative bacterial infection is thus determined not only by an individual's ability to sense endotoxin and respond to its presence, but also by numerous phenomena that inactivate endotoxin and/or prevent harmful reactions to it. Endotoxin sensing requires the MD-2/TLR4 recognition complex and occurs principally in local tissues and the liver. This review highlights the known detoxification mechanisms, which include: (i) proteins that facilitate LPS sequestration by plasma lipoproteins, prevent interactions between the bioactive lipid A moiety and MD-2/TLR4, or promote cellular uptake via non-signaling pathway(s); (ii) enzymes that deacylate or dephosphorylate lipid A; (iii) mechanisms that remove LPS and Gram-negative bacteria from the bloodstream; and (iv) neuroendocrine adaptations that modulate LPS-induced mediator production or neutralize pro-inflammatory molecules in the circulation. In general, the mechanisms for sensing and detoxifying endotoxin seem to be compartmentalized (local versus systemic), dynamic, and variable between individuals. They may have evolved to confine infection and inflammation to extravascular sites of infection while preventing harmful systemic reactions. Integration of endotoxin sensing and detoxification is essential for successful host defense.

Topics: Animals; Bacterial Infections; Endotoxins; Humans; Lipid A; Mononuclear Phagocyte System

Toll-like receptor (TLR) agonists are being developed for use as vaccine adjuvants and as stand-alone immunomodulators because of their ability to stimulate innate and adaptive immune responses. Among the most thoroughly studied TLR agonists are the lipid A molecules that target the TLR4 complex. One promising candidate, monophosphoryl lipid A, which is a derivative of lipid A from Salmonella minnesota, has proven to be safe and effective as a vaccine adjuvant in > 120,000 human doses. A new class of synthetic lipid A mimetics, the aminoalkyl glucosaminide 4-phosphates (AGPs), have been engineered specifically to target human TLR4 and are showing promise as vaccine adjuvants and as monotherapeutic agents capable of eliciting nonspecific protection against a wide range of infectious pathogens. In this review, the authors provide an update of the preclinical and clinical experiences with the TLR4 agonists, MPL (Corixa Corporation) adjuvant and the AGPs.

Topics: Adjuvants, Immunologic; Aged; Animals; Antiviral Agents; Bacterial Infections; Bacterial Vaccines; Child; Clinical Trials as Topic; Drug Design; Drug Evaluation, Preclinical; Female; Glycolipids; Humans; Immunologic Factors; Lipid A; Lymphocyte Activation; Male; Membrane Glycoproteins; Mice; Mice, Inbred BALB C; Molecular Structure; Protozoan Infections; Receptors, Cell Surface; Respiratory Syncytial Virus Infections; Respiratory Syncytial Viruses; Toll-Like Receptor 4; Toll-Like Receptors; Viral Vaccines; Virus Diseases; Virus Replication

Cationic antimicrobial peptides (CAMPs), such as defensins, cathelicidins and thrombocidins, are an important human defense mechanism, protecting skin and epithelia against invading microorganisms and assisting neutrophils and platelets. Staphylococcus aureus, Salmonella enterica and other bacterial pathogens have evolved countermeasures to limit the effectiveness of CAMPs, including the repulsion of CAMPs by reducing the net negative charge of the bacterial cell envelope through covalent modification of anionic molecules (e.g. teichoic acids, phospholipids and lipid A); expelling CAMPs through energy-dependent pumps; altering membrane fluidity; and cleaving CAMPs with proteases. Mutants susceptible to CAMPs are more efficiently inactivated by phagocytes and are virulence-attenuated, indicating that CAMP resistance plays a key role in bacterial infections.

Topics: Amino Acid Sequence; Antimicrobial Cationic Peptides; Bacteria; Bacterial Infections; Drug Resistance, Bacterial; Genes, Bacterial; Humans; Lipid A; Molecular Sequence Data; Phospholipids; Teichoic Acids; Virulence

Fatty acid biosynthesis, the first stage in membrane lipid biogenesis, is catalyzed in most bacteria by a series of small, soluble proteins that are each encoded by a discrete gene (Fig. 1; Table 1). This arrangement is termed the type II fatty acid synthase (FAS) system and contrasts sharply with the type I FAS of eukaryotes which is a dimer of a single large, multifunctional polypeptide. Thus, the bacterial pathway offers several unique sites for selective inhibition by chemotherapeutic agents. The site of action of isoniazid, used in the treatment of tuberculosis for 50 years, and the consumer antimicrobial agent triclosan were revealed recently to be the enoyl-ACP reductase of the type II FAS. The fungal metabolites, cerulenin and thiolactomycin, target the condensing enzymes of the bacterial pathway while the dehydratase/isomerase is inhibited by a synthetic acetylenic substrate analogue. Transfer of fatty acids to the membrane has also been inhibited via interference with the first acyltransferase step, while a new class of drugs targets lipid A synthesis. This review will summarize the data generated on these inhibitors to date, and examine where additional efforts will be required to develop new chemotherapeutics to help combat microbial infections.

Topics: Acetyl-CoA Carboxylase; Anti-Bacterial Agents; Bacteria; Bacterial Infections; Bacterial Proteins; Base Sequence; Desiccation; Enzyme Inhibitors; Escherichia coli; Fatty Acid Synthases; Fatty Acids; Gene Expression Regulation; Humans; Lipid A; Lipids; Models, Biological; Molecular Sequence Data; Phospholipids; Protein Conformation; Sequence Alignment; Streptococcus pneumoniae

A substantial body of knowledge has emerged over the past several decades concerning the primary and tertiary, and quaternary structure of endotoxic LPS and their contribution to the pathogenesis of gram-negative sepsis; however, important questions remain. Among them are the precise three-dimensional configuration of the LPS macromolecule and the contribution of the quaternary structure to the ability of these potent microbial factors to interact with host humoral and cellular inflammatory mediator systems. Also remaining to be sufficiently addressed is the relative contribution of endotoxin interactions with the host to the overall manifestation of disease and conditions under which such contributions serve as the pivotal event in determining outcome. The answers to these questions can be expected to provide valuable insights into potential novel therapeutic intervention strategies and approaches that will ultimately reduce both morbidity and mortality in infection from gram-negative microbes.

Topics: Animals; Bacterial Infections; Endotoxins; Humans; Lipid A; Lipopolysaccharides; Sepsis; Structure-Activity Relationship

Topics: Animals; Bacterial Infections; Clinical Trials as Topic; Humans; Lipid A; Mice; Safety; Sepsis; Shock, Septic; Structure-Activity Relationship

Topics: Antibodies, Bacterial; Antigens, Bacterial; Antitoxins; Bacterial Infections; Blood Donors; Carbohydrate Sequence; Endotoxins; Enzyme-Linked Immunosorbent Assay; Humans; Immunotherapy; Lipid A; Lipopolysaccharides; Molecular Sequence Data; Pseudomonas aeruginosa; Shock, Septic; Tumor Necrosis Factor-alpha

These studies provide exciting prospects for the future treatment of gram-negative infections. The anti-endotoxin activity of lipid X, a monosaccharide precursor of lipid A, may be a prototypic compound for agents that can block the toxic effects of endotoxin that is being actively released. In contrast, monophosphoryl lipid A, a disaccharide derivative of lipid A, stimulates host defenses against infections and tumors. With further understanding of the mechanisms by which these compounds exert these effects, we can anticipate that new and more active compounds will be developed and that further activities of existing compounds will be found.

Topics: Animals; Bacterial Infections; Endotoxins; Glycolipids; Humans; Lipid A

Unprecedented community containment measures were taken following the recent outbreak of COVID-19 in Italy. The aim of the study was to explore the self-reported future compliance of citizens with such measures and its relationship with potentially impactful psychological variables.. An online survey was completed by 931 people (18-76 years) distributed across the Italian territory. In addition to demographics, five dimensions were measured: self-reported compliance with containment measures over time (today, at 7, 14, 30, 60, 90, and 180 days from now) at three hypothetical risk levels (10, 50, 90% of likelihood of contracting the COVID-19), perceived risk, generalized anxiety, intolerance of uncertainty, and relevance of several psychological needs whose satisfaction is currently precluded.. The duration of containment measures plays a crucial role in tackling the spread of the disease as people will be less compliant over time. Psychological needs of citizens impacting on the compliance should be taken into account when planning an easing of the lockdown, along with interventions for protecting vulnerable groups from mental distress.. La apendicitis aguda (AA) es la urgencia quirúrgica abdominal más frecuente. No encontramos estudios específicos que evalúen el impacto de la pandemia causada por el coronavirus 2 (SARS-Cov-2) sobre la AA y su tratamiento quirúrgico. Analizamos la influencia de esta nueva patología sobre la AA.. Estudio observacional retrospectivo en pacientes intervenidos por AA desde enero hasta abril de 2020. Fueron clasificados según el momento de la apendicectomía, antes de la declaración del estado de alarma (Pre-COVID19) y después de la declaración del estado de alarma (Post-COVID19) en España. Se evaluaron variables demográficas, duración de la sintomatología, tipo de apendicitis, tiempo quirúrgico, estancia hospitalaria y complicaciones postoperatorias.. La pandemia por SARS-Cov-2 influye en el momento de diagnóstico de la apendicitis, así como en su grado de evolución y estancia hospitalaria. La peritonitis fue lo más frecuentemente observado. Una sospecha y orientación clínica más temprana, es necesaria para evitar un manejo inadecuado de este trastorno quirúrgico común.. The primary outcome is improvement in PaO. Findings will provide timely information on the safety, efficacy, and optimal dosing of t-PA to treat moderate/severe COVID-19-induced ARDS, which can be rapidly adapted to a phase III trial (NCT04357730; FDA IND 149634).. None.. The gut barrier is crucial in cirrhosis in preventing infection-causing bacteria that normally live in the gut from accessing the liver and other organs via the bloodstream. Herein, we characterised gut inflammation by measuring different markers in stool samples from patients at different stages of cirrhosis and comparing this to healthy people. These markers, when compared with equivalent markers usually measured in blood, were found to be very different in pattern and absolute levels, suggesting that there is significant gut inflammation in cirrhosis related to different immune system pathways to that seen outside of the gut. This provides new insights into gut-specific immune disturbances that predispose to complications of cirrhosis, and emphasises that a better understanding of the gut-liver axis is necessary to develop better targeted therapies.. La surveillance de l’intervalle QT a suscité beaucoup d’intérêt durant la pandémie de la COVID-19 en raison de l’utilisation de médicaments prolongeant l’intervalle QT et les préoccupations quant à la transmission virale par les électrocardiogrammes (ECG) en série. Nous avons posé l’hypothèse que la surveillance en continu de l’intervalle QT par télémétrie était associée à une meilleure détection des épisodes de prolongation de l’intervalle QT.. Nous avons introduit la télémétrie cardiaque en continu (TCC) à l’aide d’un algorithme de surveillance automatisée de l’intervalle QT dans nos unités de COVID-19. Les mesures automatisées quotidiennes de l’intervalle QT corrigé (auto-QTc) en fonction de la fréquence cardiaque maximale ont été enregistrées. Nous avons comparé la proportion des épisodes de prolongation marquée de l’intervalle QTc (QTc long), définie par un intervalle QTc ≥ 500 ms, chez les patients montrant une suspicion de COVID-19 ou ayant la COVID-19 qui avaient été admis avant et après la mise en place de la TCC (groupe témoin. La surveillance en continu de l’intervalle QT est supérieure à la norme de soins dans la détection des épisodes de QTc long et exige peu d’ECG. La réponse clinique aux épisodes de QTc long est sous-optimale.. Exposure to a model wildfire air pollution source modifies cardiovascular responses to HC challenge, suggesting air pollution sensitizes the body to systemic triggers.. Though the majority of HIV-infected adults who were on HAART had shown viral suppression, the rate of suppression was sub-optimal according to the UNAIDS 90-90-90 target to help end the AIDS pandemic by 2020. Nonetheless, the rate of immunological recovery in the study cohort was low. Hence, early initiation of HAART should be strengthened to achieve good virological suppression and immunological recovery.. Dust in Egyptian laying hen houses contains high concentrations of microorganisms and endotoxins, which might impair the health of birds and farmers when inhaled. Furthermore, laying hens in Egypt seem to be a reservoir for ESBL-producing Enterobacteriaceae. Thus, farmers are at risk of exposure to ESBL-producing bacteria, and colonized hens might transmit these bacteria into the food chain.. The lack of significant differences in the absolute changes and relative ratios of injury and repair biomarkers by contrast-associated AKI status suggests that the majority of mild contrast-associated AKI cases may be driven by hemodynamic changes at the kidney.. Most comparisons for different outcomes are based on very few studies, mostly low-powered, with an overall low CoE. Thus, the available evidence is considered insufficient to either support or refute CH effectiveness or to recommend one ICM over another. Therefore, further well-designed, larger RCTs are required.. PROSPERO database Identifier: CRD42016041953.. Untouched root canal at cross-section perimeter, the Hero 642 system showed 41.44% ± 5.62% and Reciproc R40 58.67% ± 12.39% without contact with instruments. Regarding the untouched area, Hero 642 system showed 22.78% ± 6.42% and Reciproc R40 34.35% ± 8.52%. Neither instrument achieved complete cross-sectional root canal debridement. Hero 642 system rotary taper 0.02 instruments achieved significant greater wall contact perimeter and area compared to reciprocate the Reciproc R40 taper 0.06 instrument.. Hero 642 achieved higher wall contact perimeter and area but, regardless of instrument size and taper, vital pulp during. The functional properties of the main mechanisms involved in the control of muscle Ca. This study showed that the anti-inflammatory effect of the iron-responsive product DHA in arthritis can be monitored by an iron-like radioactive tracer (. Attenuated vascular reactivity during pregnancy suggests that the systemic vasodilatory state partially depletes nitric oxide bioavailability. Preliminary data support the potential for MRI to identify vascular dysfunction in vivo that underlies PE. Level of Evidence 2 Technical Efficacy Stage 1 J. MAGN. RESON. IMAGING 2021;53:447-455.. La evaluación de riesgo es importante para predecir los resultados postoperatorios en pacientes con cáncer gastroesofágico. Este estudio de cohortes tuvo como objetivo evaluar los cambios en la composición corporal durante la quimioterapia neoadyuvante e investigar su asociación con complicaciones postoperatorias. MÉTODOS: Los pacientes consecutivos con cáncer gastroesofágico sometidos a quimioterapia neoadyuvante y cirugía con intención curativa entre 2016 y 2019, identificados a partir de una base de datos específica, se incluyeron en el estudio. Se utilizaron las imágenes de tomografía computarizada, antes y después de la quimioterapia neoadyuvante, para evaluar el índice de masa muscular esquelética, la sarcopenia y el índice de grasa visceral y subcutánea.. In this in vitro premature infant lung model, HF oscillation of BCPAP was associated with improved CO. Our results showed that HPC significantly promotes neurogenesis after MCAO and ameliorates neuronal injury.. Inflammatory markers are highly related to signs of systemic hypoperfusion in CS. Moreover, high PCT and IL-6 levels are associated with poor prognosis.. These findings indicate that Tetrapleura tetraptera fruit has a protective potential against stroke through modulation of redox and electrolyte imbalances, and attenuation of neurotransmitter dysregulation and other neurochemical dysfunctions. Tetrapleura tetraptera fruit could be a promising source for the discovery of bioactives for stroke therapy.

Topics: 3T3-L1 Cells; A Kinase Anchor Proteins; Acetates; Achilles Tendon; Acute Kidney Injury; Acute Pain; Acyclic Monoterpenes; Adenine Nucleotides; Adhesins, Escherichia coli; Adipocytes; Adipocytes, Brown; Adipogenesis; Administration, Inhalation; Administration, Oral; Adrenal Cortex Hormones; Adsorption; Adult; Aeromonas hydrophila; Africa; Aged; Aged, 80 and over; Agrobacterium tumefaciens; Air; Air Pollutants; Air Pollution; Air Pollution, Indoor; Algorithms; Alkaloids; Alkynes; Allosteric Regulation; Amines; Amino Acid Sequence; Amino Acids; Amino Acids, Branched-Chain; Aminoisobutyric Acids; Aminopyridines; Amyotrophic Lateral Sclerosis; Anaerobic Threshold; Angiography; Angiotensin II Type 1 Receptor Blockers; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Animal Distribution; Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Ankle Joint; Anti-Bacterial Agents; Anti-HIV Agents; Anti-Inflammatory Agents; Antibodies, Bacterial; Antifungal Agents; Antimalarials; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Antioxidants; Antiretroviral Therapy, Highly Active; Antiviral Agents; Aotidae; Apelin; Apoptosis; Arabidopsis Proteins; Argentina; Arginine; Artemisinins; Arthritis, Experimental; Arthritis, Rheumatoid; Arthroscopy; Aspergillus; Aspergillus niger; Asteraceae; Asthma; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; Auditory Cortex; Autoantibodies; Autophagy; Bacteria; Bacterial Infections; Bacterial Proteins; Bacterial Typing Techniques; Base Composition; Base Sequence; Basketball; Beclin-1; Benzhydryl Compounds; Benzimidazoles; Benzo(a)pyrene; Benzofurans; Benzoxazines; Bereavement; beta Catenin; beta-Lactamase Inhibitors; beta-Lactamases; beta-Lactams; Betacoronavirus; Betaine; Binding Sites; Biofilms; Biological Assay; Biological Availability; Biological Evolution; Biomarkers; Biomechanical Phenomena; Biopolymers; Biopsy; Bismuth; Blood Glucose; Blood Platelets; Blood Pressure; Body Composition; Body Weight; Bone Marrow; Bone Marrow Cells; Bone Regeneration; Boron; Botrytis; Brain Ischemia; Brain Neoplasms; Brain-Derived Neurotrophic Factor; Brazil; Breast Neoplasms; Breath Tests; Bronchoalveolar Lavage Fluid; Burkholderia; C-Reactive Protein; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Calcification, Physiologic; Calcium; Calcium Signaling; Calorimetry, Differential Scanning; Cameroon; Camptothecin; Candida; Candida albicans; Capillaries; Carbapenem-Resistant Enterobacteriaceae; Carbapenems; Carbohydrate Conformation; Carbon; Carbon Dioxide; Carbon Isotopes; Carcinoma, Ovarian Epithelial; Cardiac Output; Cardiomyopathy, Hypertrophic; Cardiotonic Agents; Cardiovascular Diseases; Caregivers; Carps; Case-Control Studies; Catalase; Catalysis; Cats; CD4 Lymphocyte Count; Cell Culture Techniques; Cell Differentiation; Cell Line, Tumor; Cell Membrane; Cell Movement; Cell Proliferation; Cell Survival; Cells, Cultured; Cellulose; Centrosome; Ceratopogonidae; Chickens; Child; China; Cholera Toxin; Choline; Cholinesterases; Chromatography, High Pressure Liquid; Chromatography, Liquid; Chromatography, Micellar Electrokinetic Capillary; Chromatography, Reverse-Phase; Chronic Disease; Cinnamates; Cities; Citrates; Climate Change; Clinical Trials, Phase III as Topic; Coal; Coal Mining; Cohort Studies; Coinfection; Colchicine; Colony Count, Microbial; Colorectal Neoplasms; Coloring Agents; Common Cold; Complement Factor H; Computational Biology; Computer Simulation; Continuous Positive Airway Pressure; Contrast Media; Coordination Complexes; Coronary Artery Bypass; Coronavirus 3C Proteases; Coronavirus Infections; Coronavirus Protease Inhibitors; Corynebacterium glutamicum; Cosmetics; COVID-19; Creatinine; Cross-Sectional Studies; Crotonates; Crystallography, X-Ray; Cues; Culicidae; Culture Media; Curcuma; Cyclopentanes; Cyclopropanes; Cymbopogon; Cystine; Cytochrome P-450 CYP2B6; Cytochrome P-450 CYP2C19; Cytochrome P-450 CYP2C19 Inhibitors; Cytokines; Databases, Genetic; Death; Dendritic Cells; Density Functional Theory; Depsides; Diabetes Mellitus, Type 2; Diamond; Diarylheptanoids; Dibenzofurans; Dibenzofurans, Polychlorinated; Diclofenac; Diet; Dietary Carbohydrates; Dietary Supplements; Diffusion Magnetic Resonance Imaging; Dioxins; Diphenylamine; Disease Outbreaks; Disease Susceptibility; Disulfides; Dithiothreitol; Dizocilpine Maleate; DNA Methylation; DNA-Binding Proteins; DNA, Bacterial; Dogs; Dose-Response Relationship, Drug; Double-Blind Method; Doublecortin Protein; Drosophila melanogaster; Droughts; Drug Carriers; Drug Combinations; Drug Delivery Systems; Drug Liberation; Drug Resistance; Drug Resistance, Bacterial; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Dust; Dynactin Complex; Dysferlin; Echo-Planar Imaging; Echocardiography; Edaravone; Egypt; Elasticity; Electrodes; Electrolytes; Emodin; Emtricitabine; Endometriosis; Endothelium, Vascular; Endotoxins; Energy Metabolism; Energy Transfer; Enterobacteriaceae; Enterococcus faecalis; Enterotoxigenic Escherichia coli; Environmental Monitoring; Enzyme Inhibitors; Epidemiologic Factors; Epigenesis, Genetic; Erythrocytes; Escherichia coli; Escherichia coli Infections; Escherichia coli Vaccines; Esophageal Neoplasms; Esophagectomy; Esophagogastric Junction; Esterases; Esterification; Ethanol; Ethiopia; Ethnicity; Eucalyptus; Evidence-Based Practice; Exercise; Exercise Tolerance; Extracorporeal Membrane Oxygenation; Family; Fatty Acids; Feedback; Female; Ferric Compounds; Fibrin Fibrinogen Degradation Products; Filtration; Fish Diseases; Flavonoids; Flavonols; Fluorodeoxyglucose F18; Follow-Up Studies; Food Microbiology; Food Preservation; Forests; Fossils; Free Radical Scavengers; Freund's Adjuvant; Fruit; Fungi; Gallium; Gender Identity; Gene Expression Regulation; Gene Expression Regulation, Neoplastic; Gene Expression Regulation, Plant; Gene Knockdown Techniques; Genes, Bacterial; Genes, Plant; Genetic Predisposition to Disease; Genitalia; Genotype; Glomerulonephritis, IGA; Glottis; Glucocorticoids; Glucose; Glucuronides; Glutathione Transferase; Glycogen Synthase Kinase 3 beta; Gram-Negative Bacterial Infections; Gram-Positive Bacterial Infections; Grassland; Guinea Pigs; Half-Life; Head Kidney; Heart Atria; Heart Rate; Heart Septum; HEK293 Cells; Hematopoietic Stem Cells; Hemodynamics; Hep G2 Cells; Hepacivirus; Hepatitis C; Hepatitis C, Chronic; Hepatocytes; Hesperidin; High-Frequency Ventilation; High-Temperature Requirement A Serine Peptidase 1; Hippocampus; Hirudins; History, 20th Century; History, 21st Century; HIV Infections; Homeostasis; Hominidae; Housing, Animal; Humans; Hydrocarbons, Brominated; Hydrogen Bonding; Hydrogen Peroxide; Hydrogen-Ion Concentration; Hydroxybutyrates; Hydroxyl Radical; Hypertension; Hypothyroidism; Image Interpretation, Computer-Assisted; Immunoconjugates; Immunogenic Cell Death; Indoles; Infant, Newborn; Infant, Premature; Infarction, Middle Cerebral Artery; Inflammation; Inflammation Mediators; Infrared Rays; Inhibitory Concentration 50; Injections, Intravenous; Interferon-gamma; Interleukin-23; Interleukin-4; Interleukin-6; Intermediate Filaments; Intermittent Claudication; Intestine, Small; Iridoid Glucosides; Iridoids; Iron; Isomerism; Isotope Labeling; Isoxazoles; Itraconazole; Kelch-Like ECH-Associated Protein 1; Ketoprofen; Kidney Failure, Chronic; Kinetics; Klebsiella pneumoniae; Lactams, Macrocyclic; Lactobacillus; Lactulose; Lakes; Lamivudine; Laparoscopy; Laparotomy; Laryngoscopy; Leucine; Limit of Detection; Linear Models; Lipid A; Lipopolysaccharides; Listeria monocytogenes; Liver; Liver Cirrhosis; Logistic Models; Longitudinal Studies; Losartan; Low Back Pain; Lung; Lupinus; Lupus Erythematosus, Systemic; Machine Learning; Macular Degeneration; Madin Darby Canine Kidney Cells; Magnetic Phenomena; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Magnetics; Malaria, Falciparum; Male; Mannans; MAP Kinase Signaling System; Mass Spectrometry; Melatonin; Membrane Glycoproteins; Membrane Proteins; Meniscectomy; Menisci, Tibial; Mephenytoin; Mesenchymal Stem Cells; Metal Nanoparticles; Metal-Organic Frameworks; Methionine; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Nude; Mice, Obese; Mice, Transgenic; Microbial Sensitivity Tests; Microcirculation; MicroRNAs; Microscopy, Video; Microtubules; Microvascular Density; Microwaves; Middle Aged; Minimally Invasive Surgical Procedures; Models, Animal; Models, Biological; Models, Molecular; Models, Theoretical; Molecular Docking Simulation; Molecular Structure; Molecular Weight; Morus; Mouth Floor; Multicenter Studies as Topic; Multiple Sclerosis; Multiple Sclerosis, Relapsing-Remitting; Muscle, Skeletal; Myocardial Ischemia; Myocardium; NAD; NADP; Nanocomposites; Nanoparticles; Naphthols; Nasal Lavage Fluid; Nasal Mucosa; Neisseria meningitidis; Neoadjuvant Therapy; Neoplasm Invasiveness; Neoplasm Recurrence, Local; Neoplasms, Experimental; Neural Stem Cells; Neuroblastoma; Neurofilament Proteins; Neurogenesis; Neurons; New York; NF-E2-Related Factor 2; NF-kappa B; Nicotine; Nitriles; Nitrogen; Nitrogen Fixation; North America; Observer Variation; Occupational Exposure; Ochrobactrum; Oils, Volatile; Olea; Oligosaccharides; Omeprazole; Open Field Test; Optimism; Oregon; Oryzias; Osmolar Concentration; Osteoarthritis; Osteoblasts; Osteogenesis; Ovarian Neoplasms; Ovariectomy; Oxadiazoles; Oxidation-Reduction; Oxidative Stress; Oxygen; Ozone; p38 Mitogen-Activated Protein Kinases; Pakistan; Pandemics; Particle Size; Particulate Matter; Patient-Centered Care; Pelargonium; Peptides; Perception; Peripheral Arterial Disease; Peroxides; Pets; Pharmaceutical Preparations; Pharmacogenetics; Phenobarbital; Phenols; Phenotype; Phosphates; Phosphatidylethanolamines; Phosphines; Phospholipids; Phosphorus; Phosphorylation; Photoacoustic Techniques; Photochemotherapy; Photosensitizing Agents; Phylogeny; Phytoestrogens; Pilot Projects; Plant Components, Aerial; Plant Extracts; Plant Immunity; Plant Leaves; Plant Oils; Plants, Medicinal; Plasmodium berghei; Plasmodium falciparum; Platelet Activation; Platelet Function Tests; Pneumonia, Viral; Poaceae; Pogostemon; Poloxamer; Poly I; Poly(ADP-ribose) Polymerase Inhibitors; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Polycyclic Compounds; Polyethylene Glycols; Polylysine; Polymorphism, Genetic; Polymorphism, Single Nucleotide; Population Dynamics; Portasystemic Shunt, Transjugular Intrahepatic; Positron Emission Tomography Computed Tomography; Postoperative Complications; Postprandial Period; Potassium Cyanide; Predictive Value of Tests; Prefrontal Cortex; Pregnancy; Prepulse Inhibition; Prevalence; Procalcitonin; Prodrugs; Prognosis; Progression-Free Survival; Proline; Proof of Concept Study; Prospective Studies; Protein Binding; Protein Conformation; Protein Domains; Protein Folding; Protein Multimerization; Protein Sorting Signals; Protein Structure, Secondary; Proton Pump Inhibitors; Protozoan Proteins; Psychometrics; Pulse Wave Analysis; Pyridines; Pyrrolidines; Quality of Life; Quantum Dots; Quinoxalines; Quorum Sensing; Radiopharmaceuticals; Rain; Random Allocation; Randomized Controlled Trials as Topic; Rats; Rats, Sprague-Dawley; Rats, Wistar; RAW 264.7 Cells; Reactive Oxygen Species; Receptor, Angiotensin, Type 1; Receptor, PAR-1; Receptors, CXCR4; Receptors, Estrogen; Receptors, Glucocorticoid; Receptors, Interleukin-1; Receptors, Interleukin-17; Receptors, Notch; Recombinant Fusion Proteins; Recombinant Proteins; Reducing Agents; Reflex, Startle; Regional Blood Flow; Regression Analysis; Reperfusion Injury; Reproducibility of Results; Republic of Korea; Respiratory Tract Diseases; Retrospective Studies; Reverse Transcriptase Inhibitors; Rhinitis, Allergic; Risk Assessment; Risk Factors; Rituximab; RNA, Messenger; RNA, Ribosomal, 16S; ROC Curve; Rosmarinic Acid; Running; Ruthenium; Rutin; Sarcolemma; Sarcoma; Sarcopenia; Sarcoplasmic Reticulum; SARS-CoV-2; Scavenger Receptors, Class A; Schools; Seasons; Seeds; Sequence Analysis, DNA; Severity of Illness Index; Sex Factors; Shock, Cardiogenic; Short Chain Dehydrogenase-Reductases; Signal Transduction; Silver; Singlet Oxygen; Sinusitis; Skin; Skin Absorption; Small Molecule Libraries; Smoke; Socioeconomic Factors; Soil; Soil Microbiology; Solid Phase Extraction; Solubility; Solvents; Spain; Spectrometry, Mass, Electrospray Ionization; Spectroscopy, Fourier Transform Infrared; Speech; Speech Perception; Spindle Poles; Spleen; Sporothrix; Staphylococcal Infections; Staphylococcus aureus; Stereoisomerism; Stomach Neoplasms; Stress, Physiological; Stroke Volume; Structure-Activity Relationship; Substrate Specificity; Sulfonamides; Surface Properties; Surface-Active Agents; Surveys and Questionnaires; Survival Rate; T-Lymphocytes, Cytotoxic; Tandem Mass Spectrometry; Temperature; Tenofovir; Terpenes; Tetracycline; Tetrapleura; Textiles; Thermodynamics; Thiobarbituric Acid Reactive Substances; Thrombin; Thyroid Hormones; Thyroid Neoplasms; Tibial Meniscus Injuries; Time Factors; Tissue Distribution; Titanium; Toluidines; Tomography, X-Ray Computed; Tooth; Tramadol; Transcription Factor AP-1; Transcription, Genetic; Transfection; Transgender Persons; Translations; Treatment Outcome; Triglycerides; Ubiquinone; Ubiquitin-Specific Proteases; United Kingdom; United States; Up-Regulation; Vascular Stiffness; Veins; Ventricular Remodeling; Viral Load; Virulence Factors; Virus Replication; Vitis; Voice; Voice Quality; Wastewater; Water; Water Pollutants, Chemical; Water-Electrolyte Balance; Weather; Wildfires; Wnt Signaling Pathway; Wound Healing; X-Ray Diffraction; Xenograft Model Antitumor Assays; Young Adult; Zoogloea

Endotoxin is a potent stimulus of proinflammatory response and systemic coagulation in patients with severe sepsis. Endotoxin is a component of Gram-negative bacteria that triggers an innate immune response through Toll-like receptor 4 signaling pathways in myeloid cells. We evaluated safety and tolerability of two dose regimens of eritoran tetrasodium (E5564), a synthetic Toll-like receptor 4 antagonist, and explored whether it decreases 28-day mortality rate in subjects with severe sepsis.. Prospective, randomized, double-blind, placebo-controlled, multicenter, ascending-dose phase II trial.. Adult intensive care units in the United States and Canada.. Three hundred adults within 12 hrs of recognition of severe sepsis, with Acute Physiology and Chronic Health Evaluation (APACHE) II-predicted risk of mortality between 20% and 80%.. Intravenous eritoran tetrasodium (total dose of either 45 mg or 105 mg) or placebo administered every 12 hrs for 6 days.. Prevalence of adverse events was similar among subjects treated with 45 mg or 105 mg of eritoran tetrasodium or with placebo. For modified intent-to-treat subjects, 28-day all-cause mortality rates were 26.6% (eritoran tetrasodium 105 mg), 32.0% (eritoran tetrasodium 45 mg), and 33.3% in the placebo group. Mortality rate in the eritoran tetrasodium 105-mg group was not significantly different from placebo (p = .335). In prespecified subgroups, subjects at highest risk of mortality by APACHE II score quartile had a trend toward lower mortality rate in the eritoran tetrasodium 105-mg group (33.3% vs. 56.3% placebo group, p = .105). A trend toward a higher mortality rate was observed in subjects in the lowest APACHE II score quartile for the eritoran 105-mg group (12.0% vs. 0.0% placebo group, p = .083).. Eritoran tetrasodium treatment appears well tolerated. The observed trend toward a lower mortality rate at the 105-mg dose, in subjects with severe sepsis and high predicted risk of mortality, should be further investigated.

Topics: Adult; Aged; APACHE; Bacterial Infections; Cohort Studies; Critical Care; Critical Illness; Dose-Response Relationship, Drug; Double-Blind Method; Drug Administration Schedule; Female; Follow-Up Studies; Hospital Mortality; Humans; Infusions, Intravenous; Intensive Care Units; Lipid A; Male; Maximum Tolerated Dose; Middle Aged; Prospective Studies; Risk Assessment; Sepsis; Survival Analysis; Toll-Like Receptor 4; Treatment Outcome

Topics: Adult; Aged; Antibodies, Bacterial; Antibodies, Monoclonal; Bacterial Infections; Clinical Trials as Topic; Female; Gram-Negative Bacteria; Humans; Kinetics; Lipid A; Male; Middle Aged; Sepsis

Lipopolysaccharides (LPS) are major players in bacterial infection through the recognition by Toll-like receptor 4 (TLR4). The LPS chemical structure, including the oligosaccharide core and the lipid A moiety, can be strongly influenced by adaptation and modulated to assure bacteria protection, evade immune surveillance, or reduce host immune responses. Deep structural understanding of TLRs signaling is essential for the modulation of the innate immune system in sepsis control and inflammation, during bacterial infection. To advance this knowledge, we have employed computational techniques to characterize the TLR4 molecular recognition of atypical LPSs from different opportunistic members of α2-Proteobacteria, including Brucella melitensis, Ochrobactrum anthropi, and Ochrobactrum intermedium, with diverse immunostimulatory activities. We contribute to unraveling the role of uncommon lipid A chemical features such as bearing very long-chain fatty acid chains, whose presence has been rarely reported, on modulating the proper heterodimerization of the TLR4 receptor complex. Moreover, we further evaluated the influence of the different oligosaccharide cores, including sugar composition and net charge, on TLR4 activation. Our studies contribute to elucidating, from the molecular and biological perspectives, the impact of the α2-Proteobacteria LPS cores and the chemical structure of the atypical lipid A for immune system evasion in opportunistic bacteria.

Topics: Bacteria; Bacterial Infections; Humans; Immune Evasion; Lipid A; Lipopolysaccharides; Oligosaccharides; Proteobacteria; Toll-Like Receptor 4

Acyl carrier proteins (ACPs) are small helical proteins found in all kingdoms of life, primarily involved in fatty acid and polyketide biosynthesis. In eukaryotes, ACPs are part of the fatty acid synthase (FAS) complex, where they act as flexible tethers for the growing lipid chain, enabling access to the distinct active sites in FAS. In the type II synthesis systems found in bacteria and plastids, these proteins exist as monomers and perform various processes, from being a donor for synthesis of various products such as endotoxins, to supplying acyl chains for lipid A and lipoic acid FAS (quorum sensing), but also as signaling molecules, in bioluminescence and activation of toxins. The essential and diverse nature of their functions makes ACP an attractive target for antimicrobial drug discovery. Here, we report the structure, dynamics and evolution of ACPs from three human pathogens: Borrelia burgdorferi, Brucella melitensis and Rickettsia prowazekii, which could facilitate the discovery of new inhibitors of ACP function in pathogenic bacteria.

Topics: Acyl Carrier Protein; Amino Acid Sequence; Bacterial Infections; Borrelia burgdorferi; Brucella melitensis; Catalytic Domain; Fatty Acid Synthases; Host-Pathogen Interactions; Humans; Lipid A; Molecular Dynamics Simulation; Multienzyme Complexes; Nuclear Magnetic Resonance, Biomolecular; Protein Binding; Protein Conformation; Quorum Sensing; Rickettsia prowazekii

Topics: Anti-Bacterial Agents; Bacteria; Bacterial Infections; Colistin; Drug Resistance, Bacterial; Humans; Lipid A; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Sepsis is a major cause of patient mortality and morbidity from bacterial infections. Although neutrophils are known to be important in the development of sepsis, how distinctive neutrophil subtypes regulate inflammatory processes involved in septicemia remains unclear. Preconditioning protects organisms against subsequent higher-dose exposures to the same, or even different, stimuli. Several studies have reported various effects of preconditioning on immune cells. However, the detailed mechanisms underlying neutrophil-mediated protection through preconditioning in sepsis remain unknown.

Topics: Animals; Bacterial Infections; Caveolin 1; Cell Membrane; Humans; Lipid A; Mice; Neutrophils; Sepsis; Signal Transduction; Toll-Like Receptor 9

Bacterial infection of the kidney leads to a rapid cascade of host protective responses, many of which are still poorly understood. We have previously shown that following kidney infection with uropathogenic Escherichia coli (UPEC), vascular coagulation is quickly initiated in local perivascular capillaries that protects the host from progressing from a local infection to systemic sepsis. The signaling mechanisms behind this response have not however been described. In this study, we use a number of in vitro and in vivo techniques, including intravital microscopy, to identify two previously unrecognized components influencing this protective coagulation response. The acylation state of the Lipid A of UPEC lipopolysaccharide (LPS) is shown to alter the kinetics of local coagulation onset in vivo. We also identify epithelial CD147 as a potential host factor influencing infection-mediated coagulation. CD147 is expressed by renal proximal epithelial cells infected with UPEC, contingent to bacterial expression of the α-hemolysin toxin. The epithelial CD147 subsequently can activate tissue factor on endothelial cells, a primary step in the coagulation cascade. This study emphasizes the rapid, multifaceted response of the kidney tissue to bacterial infection and the interplay between host and pathogen during the early hours of renal infection.

Topics: Animals; Bacterial Infections; Basigin; Biomarkers; Blood Coagulation; Cell Line; Cytokines; Disease Models, Animal; Epithelial Cells; Humans; Inflammation Mediators; Lipid A; Male; Nephritis; Proteome; Proteomics; Rats; Signal Transduction

A combination therapy for combined injury (CI) using a non-specific immunomodulator, synthetic trehalose dicorynomycolate and monophosphoryl lipid A (STDCM-MPL), was evaluated to augment oral antimicrobial agents, levofloxacin (LVX) and amoxicillin (AMX), to eliminate endogenous sepsis and modulate cytokine production.. Female B6D2F(1)/J mice received 9.75 Gy cobalt-60 gamma-radiation and wound. Bacteria were isolated and identified in three tissues. Incidence of bacteria and cytokines were compared between treatment groups.. Results demonstrated that the lethal dose for 50% at 30 days (LD(50/30)) of B6D2F(1)/J mice was 9.42 Gy. Antimicrobial therapy increased survival in radiation-injured (RI) mice. Combination therapy increased survival after RI and extended survival time but did not increase survival after CI. Sepsis began five days earlier in CI mice than RI mice with Gram-negative species predominating early and Gram-positive species increasing later. LVX plus AMX eliminated sepsis in CI and RI mice. STDCM-MPL eliminated Gram-positive bacteria in CI and most RI mice but not Gram-negative. Treatments significantly modulated 12 cytokines tested, which pertain to wound healing or elimination of infection.. Combination therapy eliminates infection and prolongs survival time but does not assure CI mouse survival, suggesting that additional treatment for proliferative-cell recovery is required.

Topics: Amoxicillin; Animals; Anti-Infective Agents; Bacterial Infections; Chemokines; Cord Factors; Cytokines; Disease Models, Animal; Drug Therapy, Combination; Female; Gamma Rays; Growth Substances; Immunologic Factors; Levofloxacin; Lipid A; Mice; Radiation Injuries, Experimental; Sepsis; Skin; Wound Infection

The structural prerequisites for lipopolysaccharide (LPS) and its partial structures for the activation of the Limulus clotting cascade (Limulus amebocyte lysate [LAL] test) are described and compared with the corresponding requirements for the activation of human immune cells such as mononuclear cells. A necessary, but not sufficient, structural motif for this is the presence of the 4(')-phosphate-diglucosamine backbone recognition structure ('epitope') in lipid A. High activity is only expressed by assemblies of endotoxins, but this is largely independent of the type of supramolecular aggregate structure. A particular conformation of the epitope within the lipid A assembly must be present, which is influenced by addition of further saccharide units to the lipid A moiety, but also reacts slightly to the acylation pattern. In contrast, the cytokine production of human immune cells induced by LPS sensitively depends on the type of its aggregate structure. In the case of a hexa-acylated bisphosphorylated lipid A structure, high activity is only observed with cubic inverted aggregates. Furthermore, addition of antimicrobial agents (such as polymyxin B) leads to a nearly complete inhibition of cytokine production, whereas the reduction in the Limulus assay is much lower. These data are important since a reliable determination of endotoxin concentrations, in particular with respect to its ability to elicit severe infections, is of high interest.

Topics: Animals; Bacterial Infections; Cells, Cultured; Cytokines; Endotoxins; Glucosamine; Horseshoe Crabs; Humans; Leukocytes, Mononuclear; Limulus Test; Lipid A; Lymphocyte Activation; Predictive Value of Tests; Protein Multimerization; Research Design

Innate and adaptive immune responses are initiated upon recognition of microbial molecules by Toll-like receptors (TLRs). We have investigated the importance of these receptors in the induction of pro-inflammatory cytokines and macrophage resistance to infection with Coxiella burnetii, an obligate intracellular bacterium and the etiological agent of Q fever. By using a Chinese hamster ovary/CD14 cell line expressing either functional TLR2 or TLR4, we determined that C. burnetii phase II activates TLR2 but not TLR4. Macrophages deficient for TLR2, but not TLR4, produced less tumor necrosis factor-alpha and interleukin-12 upon C. burnetii infection. Furthermore, it was found that TLR2 activation interfered with C. burnetii intracellular replication, as macrophages from TLR2-deficient mice were highly permissive for C. burnetii growth compared with macrophages from wild type mice or TLR4-deficient mice. Although LPS modifications distinguish virulent C. burnetii phase I bacteria from avirulent phase II organisms, electrospray ionization-mass spectrometry analysis showed that the lipid A moieties isolated from these two phase variants are identical. Purified lipid A derived from either phase I or phase II LPS failed to activate TLR2 and TLR4. Indeed, the lipid A molecules were able to interfere with TLR4 signaling in response to purified Escherichia coli LPS. These studies indicate that TLR2 is an important host determinant that mediates recognition of C. burnetii and a response that limits growth of this intracellular pathogen.

Topics: Animals; Bacterial Infections; CHO Cells; Coxiella burnetii; Cricetinae; Cytokines; Escherichia coli; Flow Cytometry; Gene Expression; Inflammation; Interleukin-12; Lipid A; Lipopolysaccharides; Macrophages; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mutation; Receptors, Cell Surface; Receptors, Interleukin-2; Signal Transduction; Spectrometry, Mass, Electrospray Ionization; Toll-Like Receptor 2; Toll-Like Receptor 4; Tumor Necrosis Factor-alpha

Topics: Animals; Bacterial Infections; Humans; Inflammation; Lipid A; Lipopolysaccharides; Mice; Neoplasms; Salmonella typhimurium; Vaccines, Attenuated

To determine whether cultured human decidual cells and chorion cells produce interleukin-10 (IL-10) after incubation with purified bacterial products.. Decidual cell cultures and chorion cell cultures were established by standard techniques. With confluence, monolayers of each culture were incubated with purified bacterial products, including various concentrations of lipopolysaccharide (LPS), lipid A, and lipoteichoic acid (LTA) for 16 hr in quadruplicate. Culture supernatants were collected and assayed for immunodetectable IL-10 by enzyme-linked immunoadsorbent assay (ELISA).. Both decidual cell cultures and chorion cell cultures produced significant quantities of IL-10 after stimulation with LPS, lipid A, and LTA. Cultures of decidual cells produced more IL-10 than did chorion cell cultures.. Our data indicate that both maternal decidual cells and fetally derived chorion cells can produce IL-10 after incubation with bacterial virulence factors. This finding contrasts with our previous findings in which chorion cells did not produce IL-10 after stimulation with IL-1 beta, suggesting that chorion cell production after incubation with bacterial products is independent of IL-1 beta. We speculate that the contribution of anti-inflammatory IL-10 production by human gestational tissues to the inflammatory process in these tissues may be overcome or abrogated by the pro-inflammatory process.

Topics: Bacterial Infections; Cells, Cultured; Chorion; Decidua; Female; Humans; Interleukin-10; Lipid A; Lipopolysaccharides; Obstetric Labor, Premature; Pregnancy; Pregnancy Complications, Infectious; Teichoic Acids

Topics: Amino Acid Sequence; Anemia, Hemolytic, Autoimmune; Antibodies, Anti-Idiotypic; Antibodies, Antinuclear; Antibodies, Monoclonal; Antibody Specificity; Antigens, Bacterial; Autoantigens; Autoimmune Diseases; Bacterial Infections; Cross Reactions; DNA; Erythrocytes; Genes, Immunoglobulin; Hemagglutinins; Humans; I Blood-Group System; Immunoglobulin Heavy Chains; Immunoglobulin M; Immunoglobulin Variable Region; Lipid A; Lupus Erythematosus, Systemic; Molecular Mimicry; Molecular Sequence Data; Sequence Alignment; Sequence Homology, Amino Acid

Topics: Antibodies, Monoclonal; Bacterial Infections; Bradykinin; Clinical Trials as Topic; Cytokines; Drug Design; Endotoxins; Gram-Negative Bacterial Infections; Humans; Lipid A; Nitric Oxide

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Bacterial Infections; Cross Infection; Endotoxins; Humans; Immunization, Passive; Incidence; Lipid A; Shock, Septic

Experiments were performed to test the ability of mouse antiidiotopic mAb, specific for an antilipid A mAb, to act as a vaccine against gram-negative bacterial infections. Lipid A is a conserved region of bacterial LPS. Immunization with the antiidiotopic antibodies, coupled to an immunogenic carrier protein (hemocyanin), specifically induced anti-LPS antibody responses in animals from different species. In a mouse model, this immunization resulted in protection against both lethal gram-negative bacteremia and endotoxemia. The antiidiotopic antibodies, however, did not stimulate endotoxin-associated bioactivities, such as induction of TNF and IL-1. These results support the hypothesis that an idiotope vaccine can stimulate beneficial protective immunity against gram-negative infections without the toxicity inherent in LPS.

Topics: Animals; Antibodies, Anti-Idiotypic; Antibodies, Bacterial; Bacteremia; Bacterial Infections; Bacterial Vaccines; Endotoxins; Female; Gram-Negative Bacteria; Immunoglobulin Idiotypes; Interleukin-1; Lipid A; Lipopolysaccharides; Mice; Mice, Inbred BALB C; Tumor Necrosis Factor-alpha

Lipopolysaccharide (LPS) endotoxin is implicated as the bacterial product responsible for the clinical syndrome of Gram-negative septicemia. Although the lipid A domain of LPS appears to be responsible for the toxicity of endotoxin, lipid A from the photosynthetic bacterium Rhodobacter sphaeroides (RSLA) and a disaccharide precursor of lipid A from enteric bacteria, termed lipid IVA, have little activity on human cells. Using the human promonomyelocytic cell line THP-1 and human monocytic cells, we now show that both lipid IVA and RSLA are antagonists of LPS. Complete, apparently competitive, inhibition of LPS activity is possible at a 10-100-fold excess of antagonist, as judged by measuring the release of cytokines and prostaglandin E2. Both antagonists prevent monocyte stimulation by endotoxin extracted from a variety of Gram-negative bacteria. Cells pretreated with either inhibitor and subsequently washed still show attenuated responses to LPS. Stimulation of monocytes by whole Gram-negative bacteria is also antagonized in a dose-dependent manner. Lipid X has no inhibitory effect in the same dose range as lipid IVA and RSLA. These findings rule out LPS sequestration as the explanation for the observed antagonism. Neither inhibitor alters monocyte stimulation by phorbol 12-myristate 13-acetate, Staphylococcus aureus, or purified protein derivative, demonstrating specificity for LPS. Although RSLA appears to inhibit LPS when tested with macrophages from both humans and mice, lipid IVA had the unique ability to act as an LPS antagonist with human-derived cells but to exhibit LPS-like effects with murine-derived cells. Like LPS, lipid IVA stimulated the release of both tumor necrosis factor alpha and arachidonic acid from murine-derived RAW 264.7 macrophage tumor cells. The range of concentrations necessary for lipid IVA to induce LPS-like effects in murine cells was similar to that necessary to antagonize the actions of LPS in human monocytes. The agonist activities of lipid IVA were completely inhibitable by RSLA. This unique species-dependent pharmacology observed with lipid IVA may reflect differences between human and murine LPS receptors. RSLA and lipid IVA may be useful in defining the role of LPS in Gram-negative bacterial infections and may prove to be prototypical therapeutic agents for the treatment of Gram-negative septicemia.

Topics: Animals; Arachidonic Acid; Bacterial Infections; Carbohydrate Conformation; Cell Line; Endotoxins; Escherichia coli; Hot Temperature; Humans; Lipid A; Lipopolysaccharides; Macrophages; Mice; Monocytes; Rhodobacter sphaeroides; Substrate Specificity; Tetradecanoylphorbol Acetate; Tumor Necrosis Factor-alpha

SDZ MRL 953, a new synthetic monosaccharidic lipid A, was investigated in vitro and in vivo for immunopharmacological activities. In experimental models of microbial infections, the compound was highly protective when it was administered prophylactically either once or three times to myelosuppressed or immunocompetent mice. The 50% effective doses of SDZ MRL 953 varied with the infectious agents and the route of its administration. In all cases, the 50% effective doses were about 10(3) times higher than those obtained with endotoxin from Salmonella abortus equi. SDZ MRL 953 was, however, less toxic than lipopolysaccharide by a factor of 10(4) to greater than 7 x 10(5) times in galactosamine-sensitized mice. The compound was also an effective inducer of tolerance to endotoxin. Hence, repeated dosing with the compound induced a transient resistance (greater than or equal to 1 week) to lethal challenges with endotoxin. In vitro, the compound was devoid of intrinsic antimicrobial activity, but it moderately induced the release of cytokines from monocytes and primed human neutrophils for the enhanced production of reactive oxygen metabolites in response to a soluble stimulus. The results presented here suggest that SDZ MRL 953 may be useful in a clinical setting for enhancing resistance to infections, particularly in patients undergoing myelosuppressive chemotherapy or irradiation, and for the prophylaxis of endotoxin shock.

Topics: Animals; Anti-Infective Agents; Bacterial Infections; Drug Interactions; Female; Galactosamine; Humans; Lethal Dose 50; Lipid A; Lipopolysaccharides; Mice; Mice, Inbred C57BL

In this study, limited sampling models for HA-1A human IgM monoclonal antibody were developed to predict the area under the concentration time curve from timed serum concentrations. Patients were administered 15 minute infusions of 25 mg (11 patients), 100 mg (15 patients), and 250 mg (2 patients). A detailed pharmacokinetic analysis (eight time points) was performed to obtain the area under the curve for each of the 28 patients using a one-compartment model with the values normalized to a dose of 100 mg. Various models were then developed to estimate the area under the curve from one and two timed concentrations using regression analysis methodology. Of these models, four were determined to be of interest with coefficients of determinations ranging from 0.92 to 0.97. They performed quite well in predicting the area under the curve values with relative root mean squared predictive error of 7.1 to 10.8% and relative mean predictive error of -4.5 to + 6.9%. These models should be extremely useful in larger scale, Phase II/III studies of HA-1A in correlating the estimated area under the curve with various demographic data, toxicity, and efficacy.

Topics: Antibodies, Monoclonal; Bacterial Infections; Body Fluid Compartments; Gram-Negative Bacteria; Humans; Immunoglobulin M; Lipid A; Models, Theoretical; Neoplasms

Lipid X, a monosaccharide precursor of lipid A, has been found to prevent death in animals given a lethal dose of endotoxin, but the mechanism of this protective effect is unknown. We previously reported that lipid X blocks endotoxin-induced priming of human neutrophils in a manner consistent with competitive inhibition. To determine the molecular requirements for this antiendotoxin activity, we studied several derivatives of lipid X using the neutrophil priming assay. Neutrophil priming was quantitated by measuring stimulated superoxide (O2-) release. The removal of either acyl group from lipid X or even the simple change of the amide to an ester linkage at C2 of the glucosamide ring resulted in a marked loss of antagonism. Monosaccharide analogues, structurally related to native lipid A by the presence of acyloxyacyl side chains, demonstrated marked inhibition of endotoxin-induced priming at low concentrations but an endotoxin-like, priming effect at high concentrations. The addition of a phosphate group at position 4 of the sugar moiety was the only modification studied so far that produced a pure antagonist with increased antiendotoxin activity. Demonstration of these structural requirements for the antiendotoxin activity of lipid A analogues supports the hypothesis that this effect may be mediated via specific cellular binding sites. Lipid X derivatives may be useful for studying the interaction of endotoxin with cells and their antiendotoxin activity may prove beneficial in the treatment of septicemia.

Topics: Bacterial Infections; Chemical Phenomena; Chemistry; Endotoxins; Glycolipids; Humans; In Vitro Techniques; Lipid A; Myristic Acids; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Sepsis; Superoxides; Trypan Blue

The interest in antilipid A antibodies increases in recent years. By means of an immunoenzyme test developed by the authors the frequency, quantity and characteristic of these antibodies were studied in 46 patients with chronic renal infections and in 36 healthy controls. The frequency of antilipid A antibodies class IgM is 5.7% and of class IgG it is 2.8% in the control group (healthy persons) and it is 41.3% and 19% respectively in the renal patients group. Most frequently their presence and quantity correlate with an active infection or with the convalescent period following antibiotic treatment (62.5%). This allows the use of antilipid A antibodies as a confirming marker for the presence of a heavy Gram negative infection and as a possible index for evaluation the efficacy of the treatment.

Topics: Antibodies, Bacterial; Bacterial Infections; Blood Donors; Chronic Disease; Convalescence; Gram-Negative Bacteria; Humans; Immunoglobulin G; Immunoglobulin M; Lipid A; Pyelonephritis

Enhancement of nonspecific resistance against Pseudomonas aeruginosa infection and regression of growth of Meth A fibrosarcoma by chemically synthesized lipid A-subunit analogs, 4-O-phosphono-D-glucosamine derivatives carrying 3-O- and N-linked acyl groups, were investigated. Compounds carrying an (R)-3-hydroxytetradecanoyl (C14-OH) group at the 2-N-position with (R)-3-tetradecanoyloxytetradecanoyl [C14-O-(C14)] or (R)-3-dodecanoyloxytetradecanoyl [C14-O-(C12)] groups at the 3-O-position, termed GLA-60 or GLA-63, respectively, showed strong activity about one-tenth that of natural lipid A. The protective activity of compounds carrying an (R)-3-hexadecanoyloxytetradecanyl group instead of a C14-O-(C14) or C14-O-(C12) group was very weak. GLA-59 carrying the same acyl components as those of GLA-60 but with reversed binding sites showed significant but not so strong protective activity. The activity of compounds possessing a tetradecanoyl group instead of a C14-OH group in GLA-60 or GLA-63 was weaker than that of GLA-60 or GLA-63. Intravenous or intratumoral administration of GLA-59, GLA-60 and GLA-63 induced significant regression of Meth A fibrosarcoma in terms of tumor size, tumor weight and number of cured mice. The activity of GLA-59 was almost equivalent to that of GLA-60. None of the tested compounds exhibited significant pyrogenicity at a dose of 10 micrograms/kg in rabbits.

Topics: Adjuvants, Immunologic; Animals; Bacterial Infections; Female; Fibrosarcoma; Glucosamine; Immunity, Innate; Lipid A; Mice; Mice, Inbred BALB C; Mice, Inbred ICR; Neoplasm Transplantation; Pseudomonas Infections

Topics: Antibodies, Bacterial; Bacterial Infections; Electrophoresis, Polyacrylamide Gel; Gram-Negative Bacteria; Humans; Immunoblotting; Lipid A; Lipopolysaccharides; Molecular Weight; Postoperative Complications

Monoclonal antibodies to the lipopolysaccharide (LPS) core region were produced by immunising mice with Escherichia coli strain J5 (chemotype Rc). One of these bound to the deepest part of the core, i.e., Lipid A, and reacted with other heat-killed but not live gram-negative bacilli, including E. coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. Eight other monoclonal antibodies, binding to the terminal glucose residue of Rc LPS, reacted with live cells of E. coli strains only. Thus, the O antigen does not necessarily render the core inaccessible to antibody. However, despite binding to live bacteria, these monoclonal antibodies neither enhanced phagocytic killing, nor protected mice from dying from gram-negative infection or endotoxaemia. It is concluded that antibodies reacting with the most immunodominant parts of the J5 core are not protective.

Topics: Animals; Antibodies, Monoclonal; Antigens, Bacterial; Bacterial Infections; Dose-Response Relationship, Immunologic; Enzyme-Linked Immunosorbent Assay; Epitopes; Escherichia coli; Female; Gram-Negative Bacteria; Hybridomas; Lipid A; Lipopolysaccharides; Mice; Phagocytosis; Shock, Septic

Topics: Aeromonas; Animals; Bacterial Infections; Lipid A; Lipopolysaccharides; Mice; Vibrio cholerae

It was shown here that the lethal activity of endotoxin may be considerably enhanced in experimental animals treated with different agents. Some of these agents represent killed bacteria, bacterial products or hepatotoxic agents and their sensitizing effects may be relevant to the sensitization seen during gram-negative infections. This study provided direct evidence that macrophages are cells mediating the lethal activity of endotoxin and that the direct interaction of LPS with macrophages is the first step in its initiation. Further, TNF is a macrophage mediator responsible for the induction of lethality. In normal animals as well as in the various sensitization models investigated, TNF alone was sufficient to induce lethality. Therefore, the stimulation of macrophages by LPS to produce TNF is a mechanism common to diverse lethality models. It would seem therefore that the complexity of endotoxicity in gram-negative infections is related primarily to the complexicity of the factors altering the susceptibility of the host rather than to be actual mechanisms of the lethal action of endotoxin. The identification of the factors leading to sensitization and their underlying mechanisms would contribute to a better understanding of the complex phenomenon endotoxicity.

Topics: Acetylmuramyl-Alanyl-Isoglutamine; Animals; Bacterial Infections; Bacterial Proteins; Endotoxins; Galactosamine; Gram-Negative Bacteria; Immune Tolerance; Immunization; Lipid A; Lipopolysaccharides; Macrophages; Mice; Mice, Inbred Strains; Neoplasms, Experimental; Tumor Necrosis Factor-alpha

Topics: Antibody Formation; Antigens, Bacterial; Bacterial Infections; Chemical Phenomena; Chemistry; Endotoxins; Epitopes; Gram-Negative Bacteria; Humans; Lipid A; Lipopolysaccharides; O Antigens

Lipid A is the toxic component of endotoxin in gram-negative bacteria. Antibodies to lipid A are not usually found in healthy persons (or only at a low titer) without a corresponding history of infection. Even gram-negative septicemia is found to be accompanied by only low titers. A completely different situation is seen in patients with chronic or recurrent infections due to Enterobacteriaceae and other gram-negative bacteria. Here it is notable that the antibody titer varies with the type of disorder (e. g. cystitis and pyelonephritis). A severe would infection, e. g. due to Pseudomonas aeruginosa, also leads to measurable lipid A antibody titers. Varying antibody titers can be observed in cystic fibrosis, Crohn's disease, and severe surgical infections. One can conclude that a significantly elevated antibody titer develops during an extensive tissue involvement of long duration and indeed is caused by tissue inhibition by endotoxin. Based on clinical experience, it can be assumed that lipid A antibodies present in the body have a protective effect in septic shock.

Topics: Adolescent; Adult; Antitoxins; Bacterial Infections; Child; Enterobacteriaceae Infections; Humans; Immunoglobulin G; Lipid A; Pyelonephritis; Sepsis; Urinary Tract Infections; Wound Infection

We have developed an ELISA for IgM and IgG antibodies to the core glycolipid (CGL) of the Re mutant Salmonella minnesota R 595, and to lipid A. Anti-CGL antibodies have been detected in sera from 37% of healthy blood donors, whereas anti-lipid A activities were found in 13% of individuals only. The anti-CGL and anti-lipid A activities were examined in patients in a surgical intensive care unit, selected on the basis of a definite risk of infectious complications due to Gram-negative bacteria. Of the patients who developed such infections, the rate of favourable outcome was significantly higher in patients with either stable positive or increasing anti-CGL activities than in patients found to be negative. Our results provide clear evidence that anti-CGL antibodies contribute to host defence against various Gram-negative bacteria.

Topics: Animals; Antibodies, Bacterial; Antibody Formation; Bacterial Infections; Blood Donors; Enzyme-Linked Immunosorbent Assay; Female; Genetic Variation; Glycolipids; Gram-Negative Bacteria; Humans; Lipid A; Lipopolysaccharides; Male; Rabbits; Salmonella

The levels of IgG- and IgM-antibodies against lipid A were determined by an ultramicro-ELISA in 54 children between 2 months and 13 years of age with non-obstructive urinary tract infections at the onset of the infection and subsequently after 3, 6 and 12 months. Children older than 2 years who later developed renal scarring as shown by intravenous pyelograms had higher levels of IgG antibodies than those without scars. This correlation was not found in children younger than 2 years of age. IgM-antibody levels did not correlate with the risk of scar formation. We conclude that the IgG-antibody level against lipid A is a useful indicator for early recognition of children over the age of two years who will later develop renal scars. The ultramicro-ELISA technique makes screening for children at risk possible at a low cost.

Topics: Adolescent; Bacterial Infections; Child; Child, Preschool; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoglobulin G; Immunoglobulin M; Infant; Kidney Diseases; Lipid A; Male; Pyelonephritis; Risk; Urinary Tract Infections

The ability of monophosphoryl lipid A (MPLA) to enhance nonspecific host resistance to bacterial infections was studied. Mice were treated with MPLA prior to intraperitoneal challenge with Escherichia coli or Staphylococcus epidermidis. Animals received additional MPLA for 2 days postinfection, and survival rates were determined. Ten micrograms of MPLA per mouse significantly improved the survival of animals infected with either bacterial species. Dose-response studies showed significant MPLA-induced protection at doses of 6 micrograms/kg against E. coli challenge and 60 micrograms/kg against S. epidermidis challenge.

Topics: Adjuvants, Immunologic; Animals; Bacterial Infections; Dose-Response Relationship, Drug; Lipid A; Mice

The capacity of lipid A, a structure common to the lipopolysaccharide cores of all gram-negative bacteria, to serve as an active immunizing agent in mice and to protect these animals against gram-negative infections was investigated. Active immunization experiments were also performed with the Re mutant of Salmonella minnesota 595 which carries a lipopolysaccharide composed of lipid A and three residues of ketodeoxyoctonic acid. Single injections of lipid A complexed to acid-hydrolyzed bacteria as carriers failed to induce specific protection against subsequent challenge infections with E. coli O4 and S. breslau. Repeated injections of lipid A resulted in good protection against intraperitoneal challenge with S. breslau and partial protection against intravenous challenge with the same organism but did not alter the sensitivity of mice to challenge infections with E. coli or Pasteurella multocida. Whole antisera or serum fractions from rabbits in which high titers against lipid A had been attained by repeated intravenous injections of the antigen did not protect mice against challenge infections with E. coli O4. In contrast a single injection of the Re mutant of S. minnesota antigen in combination with incomplete Freund's adjuvant provided substantial protection against an otherwise lethal intraperitoneal infection with S. breslau over a period of at least 45 days. Repeated application of the Re antigen resulted in partial protection against experimental infections with E. coli O4, S. breslau and Pasteurella multocida. Injections of S. minnesota Re 595 antiserum provided better protection against an E. coli O4 infection than lipid A sera or antibodies of the IgG or IgM type directed against this antigen.

Topics: Animals; Antigens, Bacterial; Bacterial Infections; Escherichia coli Infections; Female; Freund's Adjuvant; Immunity, Active; Immunity, Maternally-Acquired; Immunization; Immunization, Passive; Lipid A; Lipopolysaccharides; Male; Mice; Pasteurella Infections; Rabbits; Salmonella; Salmonella Infections, Animal