Differential effects of endotoxin and fibrinogen degradation products (FDPS) on liver synthesis of fibrinogen and albumin: evidence for the involvement of a novel monokine in the stimulation of fibrinogen synthesis induced by FDPS

1. Administration of endotoxin or fibrinogen degradation products (FDPs) in rats increase fibrinogen synthesis comparable to that found during the acute phase response. 2. An increased fibrinogen synthesis is also found in co-cultures of hepatocytes with peripheral blood mononuclear cells upon administration of endotoxin or FDPs, but not in primary cultures of hepatocytes alone. 3. However, the increased synthesis of fibrinogen by FDPs is not accompanied by a decreased albumin synthesis, as in the case of stimulated fibrinogen synthesis induced by endotoxin in vivo and in co-cultures of hepatocytes with peripheral blood mononuclear cells, or induced by monocytic products in vivo and in primary cultures of hepatocytes alone. 4. Since IL-1 and/or IL-6 could not be accounted for the stimulation of fibrinogen synthesis without a decreased albumin synthesis, a novel monokine produced by mononuclear cells upon FDP administration might be involved.     

The role of endotoxin of gram negative bacteria in the pathogenesis of atherosclerosis

Literature data and the results of own research on the role played by lipopolysaccharide (endotoxin) of Gram negative bacteria in the initiation and progressing of atherosclerosis are summarized. Endotoxin promotes activation of all cells taking part in the formation of atherosclerotic plaques, induces the transformation of macrophages of arterial intima into foam cells as well as endothelial lesions and hyperlipidemia, reduces the ratio of cholesterol in lipoproteins of high specific density to total blood cholesterol. With chlamydiae and enterobacteria used as examples, the role of Gram negative bacteria and their endotoxin in the etiology and pathogenesis of atherosclerosis is discussed.     

Effects of bile acids and endotoxin on the function and morphology of cultured hamster Kupffer cells

The mechanisms of hepatic reticuloendothelial cell dysfunction in obstructive jaundice were investigated using cultured hamster Kupffer cells. The introduction of free bile acids, cholic acid (CA) at concentrations over 2 mM and chenodeoxycholic acid (CDCA) over 1 mM inhibited colloidal carbon pinocytosis. CA and CDCA at concentrations over 0.5 mM inhibited IgG-coated sheep red blood cell phagocytosis. With the application of conjugated bile acid and endotoxin at concentrations over 50 micrograms/ml, endocytic function was inhibited. With bile acids, a dose-dependent increase in the concentration of beta-glucuronidase occurred in the culture medium, and with endotoxin a time-dependent increase in beta-glucuronidase was noted. Bile acids produced alterations in cell organelles before destruction of the cell membrane. The presence of endotoxin led to the appearance of large vacuoles in the cytoplasm. These observations suggest that bile acids and endotoxin inhibit Kupffer cells by different mechanisms. We tentatively conclude that bile acids rather than endotoxin influence Kupffer cells in vivo.     

Local and systemic autonomic nervous effects on cell migration to the spleen.

This work is based on the hypothesis that sympathetic nerves regulate the uptake of circulating cells by the spleen by affecting splenic blood flow and that the quantity of cells sequestered depends on whether changes in noradrenergic transmission occur at local or systemic levels. Fluorescently labeled lymphoid cells were injected into rats, and organ blood flow was measured by the microsphere method. Increased retention of cells in the spleen paralleled by increased blood flow was detected after local denervation of this organ or administration of bacterial endotoxin. A comparable enhanced splenic blood flow was observed after general sympathectomy. However, the redistribution of blood perfusion during general vasodilatation resulted in deviation of leukocyte flow from the spleen, thus resulting in reduced uptake of cells by this organ. These results indicate that, although the uptake of cells by the spleen depends on arterial blood supply, enhanced perfusion does not always result in increased cell sequestration because general vasodilatation reduces cell uptake by this organ and even overrides stimulatory effects of endotoxin.     

电磁水对血白细胞、红细胞、血小板及血管内皮细胞影响的研究

血管中白细胞等的粘附、聚集问题能够影响微循环的血流速度,是损伤血管内皮细胞乃至形成血栓的主要因素之一。在内毒素注射大白鼠的随机、对照实验中,发现电磁水能够减轻内毒素所致的炎症刺激,并能够降低白、红细胞和血小板的粘附、聚集,能降低白细胞的渗出,能提高红细胞的电泳率,能抑制血流速度的减慢和能够减轻血管内皮细胞的损伤。t检验,差异显著(P<0.01)以及差异明显(P<0.05)。揭示电磁水能够提高血细胞和血管内皮细胞的表面负电荷密度,并可以减轻外因(如,内毒素)对体内细胞和血管的损伤。说明电磁水能够改善微循环,维系正常血流和防止血栓形成。     

Influence of physical loading on the content of intestinal microflora endotoxin in blood plasma and immunity indices to endotoxin

The content of endotoxin of Gram-negative bacteria and humoral and granulocytic immunity indices to endotoxin in sportsmen and untrained persons before and after undergoing physical load were studied. The study revealed that prior to physical load the content of intestinal microflora endotoxin in the blood stream of volunteer students increased and the humoral immunity indices to endotoxin decreased. Judging by the content of cortisol in the blood, the state of stress increased after a physical load. In the groups with good adaptation a decreased endotoxin content in the blood stream was noted, especially 24 hours after load. On the contrary, in the groups with dysadaptation the content of endotoxin in blood plasma increased after a load and was accompanied by a decrease in antibody titers and in the reserve of leukocytes capable of binding endotoxin.     

Delta endotoxin is a potent inhibitor of the (Na,K)-ATPase

A 68-kDa protein, delta endotoxin, produced by Bacillus thuringiensis ssp. Kurstaki inhibits ion transport, (Na,K)-ATPase, and K+-p-nitrophenylphosphatase activity catalyzed by the Na+ pump. The Ki for inhibition of the K+-p-nitrophenylphosphatase activity of purified dog kidney (Na,K)-ATPase was approximately 0.37 microM. Delta endotoxin had a similar Ki for inhibition of (Na,K)-ATPase activity when assayed at low Na+ concentration (10 mM) but the inhibition was reversed when high concentrations of Na+ (100 mM NaCl) were added to the assay. Phosphorylation of the active site aspartyl residue with 32PO3-4 was also blocked by delta endotoxin. Ouabain-sensitive 86Rb+ uptake into intact human red blood cells was not inhibited by externally added toxin; however, strophanthidin-inhibitable 22Na+ uptake into inside-out vesicles from red blood cells was completely blocked by delta endotoxin (Ki = 0.73 microM). These data suggest that delta endotoxin must enter the cell before it can inhibit the Na+ pump.     

In vitro phagocytosis by Limulus blood cells.

Limulus blood cells maintained in culture are able to phagocytose particles under conditions where bacterial endotoxin is absent. In the presence of endotoxin, phagocytosis is inhibited because the cells are immobile under these conditions and because the extracellular gel found in the presence of endotoxin prevents cell-particle contact. It is suggested that Limulus blood cells respond to Gram-negative organisms by the formation of an extracellular gel matrix that entraps the bacteria and handles other types of foreign particles by phagocytosis.     

The influence of oestrone on the production of tumour necrosis factor by human peripheral blood adherent cells.

Human peripheral blood adherent cells (PBAC) incubated with oestrone in high concentration (10(-5) M) release, on exposure to bacterial endotoxin, an amount of tumour necrosis factor (TNF) greater than do cells incubated without the steroid. The finding may imply a non-endocrine hormonal process leading to heightened local TNF responses. This may be the basis of endotoxin hypersensitivity in pregnancy.     

Endotoxin-induced changes in the rabbit's blood picture

The authors studied changes in the rabbit's blood picture in the first 24 hours after the administration of three different doses of endotoxin. The most pronounced changes were observed in the white blood component, particularly the granulocytes, which almost vanished from the blood stream immediately after the endotoxin was injected. In 24 hours granulocytopenia was succeeded by marked granulocytosis. Changes in the lymphocytes were smaller; the lymphocyte count fell slightly about 3 hours after the injection of endotoxin, but by 24 hours it was almost normal again. The platelet count also fell after the administration of endotoxin, but the red blood picture remained virtually the same.     

Accumulation of activated lymphocytes in liver of endotoxin treated rabbits.

Intravenous administration of endotoxin in doses, 1.0 mg/kg, 0.1 mg/kg or 0.01 mg/kg caused activation (in the sense of nucleolar RNA synthesis) of the lymphocytes in peripheral blood, kidney and liver in rabbits. The evaluation of the ratio of lymphocyte count to the number of organ tissue cells leads to the conclusion that the accumulation of endotoxin activated lymphocytes occurs in liver.     

Endotoxin in blood and tissue in the sudden infant death syndrome

Although the explanation for sudden infant death syndrome (SIDS) remains unknown, an increasing body of evidence now exists to suggest a possible role for bacterial toxins in the aetiology, and a number of investigators have considered that endotoxaemia could explain some of the associated features. Following the development of an animal model which confirmed that endotoxaemia could be detected after death, we studied endotoxin levels in blood and tissue samples taken at autopsy from SIDS infants, child controls and adult controls. There were significant correlations between endotoxin levels in blood and the various organs sampled particularly in SIDS cases and child controls, and blood endotoxin levels in SIDS cases were higher in those infants where there was histological evidence of mild to moderate inflammation. However, overall no significant differences were found between endotoxin levels in blood or tissue in the three study groups. Further studies into possible actions or interactions of endotoxin in SIDS are required.     

Effect of bacterial endotoxin on the phagocytic activity of the reticulo-endothelial system in rabbits of different age

Stimulation of the phagocytic activity of the reticulo-endothelial system with bacterial endotoxin was studied in newborn rabbits in the period in which they do not actively form antibodies to bacterial antigens. A markedly accelerated clearance of colloidal carbon from the blood was found in five-day-old rabbits (tested by the technique of Biozzi, Benacerraf and Halpern 1953) when relatively high doses of endotoxin were used. It is assumed that the increased resistance to infection which may be elicited in young animals in that period is due to stimulation of cellular defence mechanisms. By comparison of the stimulating effect of endotoxin on phagocytosis in five-day-old, one-month-old and adult rabbits it was found that the phagocytic cells of the R.E.S. are more susceptible to the effect of endotoxin in adults than in newborns. This difference is evident from comparisons of the phagocytic indices K and the corrected phagocytic indices α in three age groups of rabbits stimulated with different doses of endotoxin. The possible mechanism and cause of differences in sensitivity of young and adult individuals is discussed.     

Human C4-binding protein: N-terminal amino acid sequence analysis and limited proteolysis by trypsin

Fres isolated blood cells recombined with normal heparinized plasma and then incubated with endotoxin, induced a 100-fold increase in monocyte tissue thromboplastin synthesis. In contrast, recombination of these cells with heat inactivated plasma, cobra venom factor-treated plasma, Ca²⁺-free plasma, or BioRex 70-treated plasma (plasma free of Clq and D) before incubation with endotoxin, failed to induce monocyte synthesis of tissue thromboplastin. These results strongly support the hypothesis that complement is required for endotoxin stimulation of blood monocyte synthesis of tissue thromboplastin.     

Enhanced antibody response in retrovirus-infected mice treated with endotoxin or nontoxic polysaccharide derivative

Friend leukemia virus (FLV) is a retrovirus which causes marked suppression of the immune response of genetically susceptible mice. In the present study the depressed antibody response to sheep erythrocytes by spleen cells from FLV-infected mice was partially reversed by injection of either a bacterial endotoxin or a nontoxic polysaccharide derivative directly into infected mice or by addition to spleen cell cultures from these mice immunized in vitro with sheep red blood cells (SRBC). The endotoxin and PS in a dose-related manner markedly increased the antibody responsiveness of the spleen cells to SRBC. Thus these results indicate that the nontoxic polysaccharide derivative has properties equivalent to the toxic endotoxin in enhancing the antibody responsiveness of FLV-suppressed spleen cells to a T-cell-dependent antigen like SRBC.     

Augmenting effect of antibiotics on endotoxin activity may cause a safety problem

Enhancing/interfering effect of antibiotics on endotoxin was evaluated using the endotoxin test and the cell line assay in 28SC cells that has a responsiveness consistent with that of human peripheral blood. When a total of 21 products of seven different kinds of antibiotics were tested, none showed any significant effect on the endotoxin test at its therapeutic dose. However, aminoglycosides showed a significant augmenting effect on IL-6 induction of endotoxin in 28SC cells. Detailed examination of the augmenting effect was made on spectinomycin in the in vitro cell line assay and also in the lethal endotoxin challenge assay in D -galactosamine-treated mice. Spectinomycin also enhanced the endotoxin lethality in D -galactosamine-treated mice. A kinetic analysis in endotoxin-sensitized 28SC cells revealed that the augmentation takes place as quickly as 10 min after spectinomycin treatment. Accordingly, a special caution concerning the augmenting effect was assumed necessary for the safety control of antibiotic products as well as for selecting antibiotics for the therapeutic use.     

Electron microscopic study of the effects of endotoxin on the cells of the hepatic sinusoid in normal and BCG sensitized mice.

Electron microscopic studies were conducted to access ultrastructural alterations in Kupffer cells and other cells lining the hepatic sinusoids at the peak of mediator release two hours after challenge with low doses of endotoxin under various conditions including reticuloendothelial system (RES) expansion and activation with BCG. BCG is known to sensitize animals to endotoxin rendering normally innocuous, low doses of endotoxin lethal. Low non-lethal doses (5 micrograms) of endotoxin activated Kupffer cells as well as caused isolated foci of cellular injury. However, animals which were treated with BCG had a highly activated and expanded RES system as evidenced by enlarged Kupffer cells with many extended cellular processes. Granulomas were prevalent and many reactive cells were present. After two hours marked cellular injury occurred to sinusoid lining and parenchymal cells when BCG treated animals were challenged with these same low doses of endotoxin. Cellular debris, fibrin, and platelets were observed in sinusoids often associated with Kupffer cells. These results suggest that the functional state of Kupffer cells is an important determinant in the host response to endotoxin. While there appears to be an effective clearance of endotoxin; the release of mediators by the highly activated Kupffer cells can be toxic causing hepatocellular injury.     

High Susceptibility of Strain A Mice to Endotoxin and Endotoxin-Red Blood Cell Mixtures.

Heppner, Gloria (University of California, Berkeley), and David W. Weiss. High susceptibility of strain A mice to endotoxin and endotoxin-red blood cell mixtures. J. Bacteriol. 90:696-703. 1965.-Strain A mice were shown to be considerably more susceptible to lethal effects of endotoxin lipopolysaccharide (LPS) than mice of several other strains. Complexes of sublethal quantities of LPS and sheep red blood cells were synergistically toxic for strain A mice. Separate administration of sheep red blood cells and heat-killed salmonellae, in either order and as long as 24 hr apart, also proved to be synergistically lethal for strain A mice, but not for R(III) animals studied comparatively. Sheep red blood cell lysates possessed the ability of the intact cells in forming lethal combinations for strain A mice with killed salmonellae. Strain A red blood cell-killed salmonellae complexes were also lethal for strain A mice, but less so then complexes made with sheep red blood cells. A x R(III) F(1) hybrid animals showed the same resistance characteristics as the resistant R(III) parental strain. Possible explanations for these findings are suggested, and their relevance to an immunological mode of action of endotoxin lethality is discussed.     

The role of macrophages in the uptake of endotoxin by the mouse liver.

The purpose of this investigation was to analyse the macrophage subpopulations involved in the uptake of endotoxin in the liver. The results show that in normal B10.D2 mice the liver macrophages constitute a heterogeneous population of cells which, depending on their state of differentiation, are distinguished by their differential distribution in the liver acinus and by their ability to phagocytose latex. Following the intravenous administration of endotoxin (lipopolysaccharide = LPS) from Salmonella abortus equi, endotoxin-carrying non-parenchymal cells of the liver (NPLC) were investigated immunohistochemically (in situ) and immunocytochemically (after isolation) between 1 h and 14 days after the injection. The endotoxin content of the blood and of isolated NPLC was also determined, using radioactivity labeled LPS. Following LPS injection, the total number of macrophages in the liver increased, reaching a maximum after 3 days. There was a striking increase in the ratio of mature to immature macrophages. After day 3, the number of macrophages decreased again, returning to the pre-injection values by day 14. 1 h after the administration of LPS, 41% of the isolated NPLC were already endotoxin-positive, a percentage which remained constant until the 3rd day. Thereafter, the number of LPS-bearing cells increased to a maximum of about 52% on the 5th day. This increase mostly involved macrophages which had taken up endotoxin. Concurrent with these changes there was a threefold increase in radioactivity-labeled LPS from the 7th h to the 5th day after injection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Suppressed in vitro blastogenic responsiveness of rat spleen cells after continuous infusion of endotoxin by an implanted osmotic pump

Continuous infusion of a gram-negative bacterial endotoxin in relatively small doses into rats by means of an implanted osmotic pump was studied. The model system was designed to examine the effects of endotoxin on the blastogenic response of spleen cells to the endotoxin itself and to a nonspecific T-cell mitogen, concanavalin A (Con A). Rats were implanted with an osmotic pump which delivered saline for the first 42 hr to provide postsurgical recovery before the onset of endotoxin infusion. Previous studies had shown that during the first 1-4 days after administration of endotoxin marked alterations of metabolism and some changes in physiologic parameters such as blood pressure and in vitro myocardial performance occurred. In the present study the blastogenic responsiveness of spleen cells to endotoxin itself as well as to the nonspecific T-cell mitogen Con A was markedly decreased after several days of continuous administration of endotoxin. Control animals receiving only saline for the same period of time showed a similar depression of blastogenic responsiveness to the lipopolysaccharide (LPS), as well as to Con A, however, with a delay of 2-4 days before comparable levels of suppression became evident. These results indicate that marked alterations of immune competence as measured by blastogenesis of spleen cells to Escherichia coli LPS and to a mitogen such as Con A may occur after implantation of an osmotic pump, with or without continuous infusion of endotoxin. Further studies seem warranted to determine the role of the foreign body reaction to the osmotic pump as well as to the endotoxin administered by the pump.