Hageman factor activation and tight junction disruption in mice challenged with attenuated endotoxin.

Endotoxin treated with chromium chloride is less toxic to mice than the parent molecule, but can disrupt intestinal permeability barriers and has an enhanced ability to activate Hageman factor.     

Claudin-17 forms tight junction channels with distinct anion selectivity

Barrier properties of tight junctions are determined by the claudin protein family. Many claudins seal this barrier, but others form paracellular channels. Among these, no claudins with general and clear-cut anion selectivity have yet been described, while for claudin-10a and claudin-4, only circumstantial or small anion selectivities have been shown. A claudin with unknown function and tissue distribution is claudin-17. We characterized claudin-17 by overexpression and knock-down in two renal cell lines. Overexpression in MDCK C7 cell layers caused a threefold increase in paracellular anion permeability and switched these cells from cation- to anion-selective. Knockdown in LLC-PK(1) cells indorsed the finding of claudin-17-based anion channels. Mutagenesis revealed that claudin-17 anion selectivity critically depends on a positive charge at position 65. Claudin-17 expression was found in two organs: marginal in brain but abundant in kidney, where expression was intense in proximal tubules and gradually decreased towards distal segments. As claudin-17 is predominantly expressed in proximal nephrons, which exhibit substantial, though molecularly not defined, paracellular chloride reabsorption, we suggest that claudin-17 has a unique physiological function in this process. In conclusion, claudin-17 forms channels within tight junctions with distinct anion preference.     

Hageman factor (factor XII) activity in synovial fluid of rheumatoid arthritis patients and its possible pathogenic significance

Résumé Nous avons constaté que l'activité spécifique du facteur de Hageman dans le fluide synovial de malades atteints de polyarthrite chronique évolutive est beaucoup plus elevée que celle d'autres agents de coagulation. L'activité du facteur de Hageman a été isolée du fluide synovial et de la suspension de leucocytes par adsorption sur kaolin et élution au pH alcalin.     

Influence of oral glucose feeding on endotoxin lethality in mice

Summary Prolonged feeding of physiological solutions of glucose (5%) by gavage did not protect against either endotoxin death or liver glycogen depletion in mice.Supported by grants from the INSERM (CL 76.5.001.4), the CNRS (03 7860) and the DGRST. Thanks are due to M. Philippe for technical assistance.Maitre de Recherche au CNRS, to whom all correspondance should be addressed.     

Protective effect of native levan on endotoxin toxicity in mice and rats

Summary High polymer levan administered to mice and rats before the injection of endotoxin partly protects the animals from the lethal effects of the LPS.This study summarizes a thesis in partial fulfilment of the requirements for the degree of Master of Medical Sciences in the School of Continuing Medical Education of the Tel-Aviv University Sackler Medical School.     

The effect of endotoxin on membrane fatty acid composition in BCG-sensitized mice

The effects of endotoxin on mouse liver phospholipid fatty acid composition have been investigated. Administration of endotoxin from Salmonella abortus equi led to a decrease in the polyunsaturated fatty acid content of livers from mice sensitized with Bacille Calmette Guérin (BCG). The content of arachidonic acid fell significantly in both the phosphatidylcholine and phosphatidylinositol fractions whereas in the phosphatidylethanolamine fraction the linoleic acid content was significantly reduced. The polyunsaturated fatty acids were replaced by increased amounts of oleic acid and palmitic acid, leading to a reduction in the polyunsaturated to saturated fatty acid ratio.     

The effect of endotoxin on membrane fatty acid composition in BCG-sensitized mice

Summary The effects of endotoxin on mouse liver phospholipid fatty acid composition have been investigated. Administration of endotoxin fromSalmonella abortus equi led to a decrease in the polyunsaturated fatty acid content of livers from mice sensitized with Bacille Calmette Guérin (GCG). The content of arachidonic acid fell significantly in both the phosphatidylcholine and phosphatidylinositol fractions whereas in the phosphatidylethanolamine fraction the linoleic acid content was significantly reduced. The polyunsaturated fatty acids were replaced by increased amounts of oleic acid and palmitic acid, leading to a reduction in the polyunsaturated to saturated fatty acid ratio.     

Increase of haptoglobin concentration in mouse serum by endotoxin and by a serum factor

Résumé L'injection de sérums provenant de différentes souches de souris, ainsi que de rats, de hamsters et de lapins, respectivement traités au Rivanol, de même que l'injection d'endotoxine bactérienne à des souris de souche C57Bl a pour effet d'augmenter la concentration d'haptoglobine dans le sérum de ces dernières. La fraction purifiée de 7S-globulines sériques humaines réduit cet effet.     

Multiple APUD system (neural crest) tumors caused by endotoxin in suckling mice

Summary In suckling mice injected i. p. with endotoxin on the 1st day after birth and surviving up to the 4th day, multiple tumors and heterotopic melanin pigmentation occurred in the sites where the neural crest cells may be present.     

Studies on the effects of phenobarbital and endotoxin on the toxicity and metabolism of 6-mercaptopurine in mice

Summary The administration of phenobarbital and endotoxin altered the toxicity and metabolism of 6-mercaptopurine in mice. These results indicate that the effects of 6-mercaptopurine may be modified by the activity of the drug-metabolizing enzyme.     

The influence of bacterial endotoxin on the formation of antibody-forming spleen cells in mice immunized with sheep red blood cells

Zusammenfassung Es wird berichtet, dass die simultane i.v. Injektion vonSerratia marcescens-Endotoxin mit i.p. verabfolgten Schafbluterythrocyten bei weissen Mäusen zu einer beschleunigten Bildung hämolysinbildender Milzzellen und zu einem verzögertem Abfall dieser kompetenten Zellen zwischen dem 7. und 30. Tage nach der Immunisierung führt. Eine echte Vermehrung plaquebildender Milzzellen wurde jedoch nicht gefunden. Weiterhin liess sich zeigen, dass die alleinige i.v. Injektion von bakteriellem Lipopolysaccharid eine mässige Proliferation von in geringer Zahl vorhandenen antikörperbildenden Milzzellen bewirkt.

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This work was supported by research grant No. Fi 115/1 of the Deutsche Forschungsgemeinschaft.     

Kinins and kininogen in endotoxin shock

Résumé Aucune quantité détectable de kinines ne fut trouvée après administration d'endotoxine et l'on n'obtint pas de différence significative dans le contenu plasmatique en kininogènes après l'injection. Nos résultats n'attribuent aux kinines aucune participation significative à l'hypotension du choc endotoxique.

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Supported in part by a grant of the Consejo Nacional de Investigaciones Científicas y Técnicas (CNICT), Argentina.     

Hypersensitivity to endotoxin hepatotoxicity in rats with inflammatory lesions

The ratio of sinusoidal nonparenchymal cells to hepatocytes in rat liver was significantly increased following induction of inflammation, and decreased after subsequent exposure to endotoxin, particularly in the region around the terminal portal venules. Rats with inflammatory lesions were more sensitive to endotoxin hepatocytotoxicity than normal controls, as judged from the dose-dependent increase in activity of serum transaminases and from the extent of liver tissue injury. In addition, these animals, which were already in a state of depletion of hepatic glycogen, demonstrated marked hyperglycemia 24 h after endotoxin administration in small doses of less than 2 mg/kg.     

Macrophage activation in mice lacking thymus-derived (T) cells

Zusammenfassung Ein gewisser Grad von Makrophagenaktivierung, gemessen an der Fähigkeit der Listerien-Elimination, wird auch in adult thymektomierten, mit Knochenmark rekonstituierten Mäusen sowie in nude/ nude-Mäusen beobachtet und daraus der Schluss gezogen, dass die Makrophagenaktivierung nicht unter allen Umständen mit der Anwesenheit von T-Lymphozyten verknüpft sein muss.