PubMed Health⌕ Search

Biomedical subjects

C Galanos

Publications and source records attributed to C Galanos.

At least 127 records · Page 7Linked to original sources
PubMed1985

Comparison of the capacity of two lipid A precursor molecules to express the local Shwartzman phenomenon.

It has been shown recently that a Salmonella lipid A precursor molecule (Ia) and its synthetic counterpart are inactive in expressing the local Shwartzman reaction in both homologous and heterologous systems in combination with lipid A. Precursor Ia contains a bisphosphoryl-beta-1,6-glucosamine disaccharide substituted by 4 mol of (D)-3-hydroxytetradecanoyl residues. Escherichia coli lipid A, on the other hand, which contains two additional non-hydroxylated acyl residues in the form of two 3-acyloxyacyl units, is highly active. We have recently isolated a lipid A precursor molecule (Ib) with the same basic structure as precursor Ia, which contains, however, one additional non-hydroxylated (hexadecanoic) fatty acid forming one 3-acyloxyacyl residue. A comparison of precursor Ia and Ib in homologous and cross-reacting Shwartzman systems confirmed that precursor Ia completely lacked the capacity to prepare the skin for, or to elicit, the Shwartzman reaction. In contrast, precursor Ib was strongly active in inducing the local Shwartzman reaction both when administered intradermally as a preparatory agent and when administered intravenously as a provocatory agent. The results indicate that the additional presence of at least one fatty acid either as such or as an acyloxyacyl residue (as in precursor Ib) is a prerequisite for the ability of the molecule to induce the local Shwartzman phenomenon.

Animals↗
PubMed1985

Excretion of radioactivity in faeces and urine of rats injected with 3H,14C-lipopolysaccharide.

The route of excretion of lipopolysaccharide (LPS) and its possible degradation in vivo was studied in rats using biosynthetically radiolabelled LPS from Salmonella abortus equi, carrying 3H activity exclusively in fatty acids and 14C activity in fatty acids and sugars. Following intravenous injection of the above LPS in AS2 rats with or without anaesthesia, excretion of radioactivity occurred mainly in the faeces and to smaller extent in urine. The rate of excretion was slow, a large part of the radioactivity being still present in the liver after 14 days. In faeces the percent recovery of 3H (18%) was lower than that of 14C (32%) suggesting loss of tritium activity and thereby of fatty acids from the excreted LPS. A similar loss of tritium was also found in the material remaining in the liver and spleen 14 days after LPS administration. In urine the material recovered during 14 days (about 7% of injected) was different from the original LPS, 70% of 14C activity being dialysable and practically all 3H activity being volatile. Similar results were also obtained following administration of the LPS intraperitoneally under anaesthesia. However, when the LPS was administered intraperitoneally without anaesthesia, in the majority of the animals, 90% of 14C and 54% of 3H was excreted in faeces within 3 days, suggesting that both route of administration and use of anaesthesia during injection influence the subsequent rate of excretion of LPS.

Animals↗
PubMed1984

Endotoxic properties of chemically synthesized lipid A part structures. Comparison of synthetic lipid A precursor and synthetic analogues with biosynthetic lipid A precursor and free lipid A.

Synthetic lipid A part structures corresponding structurally to a biosynthetic lipid A disaccharide precursor have been analyzed for endotoxic activity in several systems in vivo and in vitro. It was found that a synthetic beta-1,6-linked D-glucosamine disaccharide, which carries four molar equivalents of (R)-3-hydroxytetradecanoyl residues in positions 2, 3, 2' and 3' and phosphoryl groups in positions 1 and 4' (preparation 406), exhibited lethal toxicity, B lymphocyte mitogenicity, the capacity to engender prostaglandin formation in macrophages and to induce endotoxic tolerance, as well as serological lipid A antigenicity. On a weight basis, preparation 406 was of comparable activity to lipid A precursor and bacterial free lipid A. Preparation 406, like lipid A precursor, lacked, however, the ability to induce the local Shwartzman phenomenon and both preparations were of moderate pyrogenicity. Two further synthetic analogues which contained only one phosphoryl group (preparation 404 at C-4', preparation 405 at C-1) showed comparable or diminished activity depending on the test system employed, except in the capacity to inactivate complement where they exhibited, in contrast to preparation 406, significant activity. The results show that the endotoxic principle of lipopolysaccharides, as postulated previously is embedded in the lipid A component. Our results also suggest initial conclusions on the structural requirements for the expression of endotoxin activities.

Animals↗
PubMed1984

Identification of endotoxin-positive cells in the rat lung during shock.

Following an intravenous administration into rats of a shock-inducing dose of endotoxin (2 mg) the lipopolysaccharide (LPS) was demonstrated immunohistochemically (light and electron microscopy) and determined quantitatively (radio-labelled LPS) in the lung tissue and in isolated alveolar macrophages. At different times after LPS injection morphological investigations of the pulmonary tissue and alveolar macrophages were carried out. One hour after endotoxin treatment 3% of the alveolar macrophages were already LPS-positive. The maximum extent of the immunoperoxidase reaction for endotoxin (100% cells involved) was observed on day 3, the vast majority (98%) of the alveolar macrophages being LPS-positive still on day 14. 0.9% of the injected radio-labelled LPS preparation was found to be associated with lung tissue on day 3. By this time 0.173 microgram LPS/10(6) alveolar macrophages was detected. During the time of ultrastructural investigation endotoxin appeared in the lung only within cells. By their high capacity for storing endotoxin and their numerical superiority the mononuclear phagocytes are the leading LPS-positive cells in the lung, although granulocytes, endothelial cells, and alveolar epithelial cells were sometimes also involved. The accumulation of a high percentage of activated macrophages in the lung seen in the late stage of shock could represent at least one of the main factors leading to damage of pulmonary tissue. The correlation between appearance of LPS-positive macrophages and histological signs of lung tissue injury in the present investigation is striking.

Animals↗
PubMed1984

Haemorrhagic tumour necrosis following endotoxin administration. I. Communication: morphological investigation on endotoxin-induced necrosis of the methylcholanthrene (Meth A) tumour in the mouse.

Endotoxin induced necrosis of the Meth A mouse tumour has been investigated using macroscopic, histological and ultrastructural examination methods. On the 8th day after tumour cell transplantation, the animals received a relatively non-toxic dose of the Salmonella abortus equi endotoxin intravenously. The natural history of the tumour necrosis took the following course: The earliest morphological changes could be seen with the electron microscope 90 min after administration of the endotoxin, and were seen as an interstitial oedema with separation of the tumour cells. Haemorrhagic necrosis of the tumour was complete 4 hours after injection, and could be easily recognized with the naked eye. Rejection of the necrotic malignant tumour was complete two weeks after LPS administration. Only minor residual scarring of the belly-wall remained. Haemorrhagic tumour necrosis due to endotoxin can be compared with the localized Shwartzman reaction and probably involves tumour necrotizing factor (TNF). For complete destruction of a tumour by haemorrhagic necrosis the size of the tumour is critical. Certain regression after endotoxin administration depends upon additional T-cell-mediated immunity (provided the tumour is immunogenic). In contrast to the haemorrhagic necrosis, BCG-induced tumour regression is accompanied by granulomatous inflammation, which may be responsible for destruction of the tumour.

Animals↗
PubMed1984

Circulating lipid A antibodies despite absence of systemic endotoxemia in patients with Crohn's disease.

Lipid A is a component common to endotoxins of gram-negative bacteria. It has been suggested that the gut wall of patients with inflammatory bowel disease is more permeable to luminal bacterial macromolecules which may stimulate the gut-associated lymphoid tissue. We therefore investigated 40 patients with Crohn's disease (CD) and 23 patients with ulcerative colitis (UC) with respect to their lipid A antibody titers and presence of endotoxins (Limulus test). Both tests were performed simultaneously using peripheral venous blood. Systemic endotoxin was demonstrated in only two of the patients. The lipid A antibody titers in the CD patients were significantly higher than either in patients with UC or in 42 healthy controls. Lipid A titers of patients with UC did not differ from those of controls. Titers of lipid A were significantly higher in patients with active Crohn's disease than in patients with inactive disease. It is concluded that systemic endotoxemia occurs rarely in patients with inflammatory bowel disease; however, despite this virtual absence of endotoxins in their peripheral blood, patients with CD show an increase in antibody formation against lipid A. This is suggestive of an altered immunologic reactivity against endotoxins in patients with CD and may be relevant to the pathogenesis of this disease.

Adolescent↗
PubMed1984

Hepatocellular clearance function of bacterial lipopolysaccharides and free lipid A in mice with endotoxic shock.

Hepatic uptake of bacterial lipopolysaccharides (LPS) in defined salt forms and free lipid A was studied in C3H mice. Extracts of 14C-labeled and unlabeled LPS from Salmonella abortus equi and lipid A from Salmonella minnesota R 595 (Re) were administered intravenously in doses sufficient to induce endotoxic shock. Sixty minutes after administration of 14C-LPS, 40% of the total activity was found in the liver tissue, 10% was in the isolated nonparenchymal cells, and only 1% was in the isolated hepatocytes. However, at this time only one third of the hepatocytes could be isolated; the other two thirds were obviously damaged. After 240 minutes, 55% of the total activity was measured in the liver tissue. The nonparenchymal cells had 8% of the activity, and all hepatocytes were damaged. By use of immunofluorescence, LPS S abortus equi was localized in sinusoidal cells 5 to 10 minutes after administration, and LPS S minnesota R 595 and lipid A were found in both nonparenchymal and parenchymal liver cells. All toxins were localized in both cell populations 60 and 240 minutes after injection. After application of LPS or lipid A, the third complement component (C3) was detectable in sinusoidal cells. In decomplemented mice the hepatic deposits of LPS and lipid A were unaffected, without demonstration of C3. The data indicate that LPS and lipid A interact in vivo with Kupffer cells and hepatocytes. Hepatic clearance of endotoxin seems to be independent of complement.

Animals↗
PubMed1984

Biological activities of synthetic lipid A analogs: pyrogenicity, lethal toxicity, anticomplement activity, and induction of gelation of Limulus amoebocyte lysate.

Chemically synthesized lipid A analogs were investigated for several endotoxic activities, including pyrogenicity, lethal toxicity, anticomplement activity, and the capacity to gelate Limulus amoebocyte lysate in comparison to natural lipid A. The synthetic preparations contained D-glucosamine or D-glucosamine-beta-1,6-D-glucosamine disaccharide substituted by ester- and amide-bound hydroxylated or non-hydroxylated fatty acids and by phosphate groups in different combinations. Some preparations which were insoluble in water were succinylated and thus rendered more soluble. Strong biphasic pyrogenic responses with a maximal increase in body temperature of 1 to 2 degrees C were obtained with 50 micrograms/kg doses of 3 disaccharide preparations of 15 tested. With two preparations (50 micrograms/kg) moderate pyrogenicity with monophasic fever curves and a maximal temperature increase of about 0.6 degrees C was obtained. Lethal toxicity tests were carried out in galactosamine-sensitized mice. Of 15 synthetic preparations, 4 exhibited lethal toxicity under these conditions. The effective doses of the lipid A analogs in both in vivo tests were, however, several hundred times higher than those of bacterial lipid A. For the activities in vivo, hydroxyacyl residues seemed to be important. Anticomplement activity was demonstrable in seven preparations, one of which expressed an activity comparable to that of lipid A. Preparations containing non-hydroxylated fatty acids seemed to be most active in this test. None of the synthetic preparations was found to exhibit gelation activity for Limulus amoebocyte lysate when tested in doses up to 0.4 micrograms, whereas bacterial free lipid A was active in doses of about 2 pg. None of the monosaccharide derivatives exhibited any of these activities.

Animals↗
PubMed1984

Mitogenic activities of synthetic lipid A analogs and suppression of mitogenicity of lipid A.

The effect of synthetic lipid A analogs on murine spleen cells was studied. The preparations represented D-glucosamine and D-glucosaminyl-beta 1,6-D-glucosamine disaccharide derivatives substituted in different combinations by ester- and amide-bound fatty acids and by phosphate groups. Significant mitogenic activity was demonstrated with a number of synthetic disaccharide preparations; however, their potency was lower than that of lipid A. The synthetic preparations were not mitogenic for spleen cells from C3H/HeJ mice. Furthermore, the mitogenicity of the synthetic preparations was abolished after binding with polymyxin B. The results indicate that for expression of mitogenicity, a phosphate group at position 1 of the reducing glucosamine and amide-bound acyloxyacyl residues are important factors. Some of the synthetic preparations containing the diglucosamine backbone and expressing relatively low mitogenicity suppressed B-cell mitogenicity of lipid A. Although these preparations were lytic for erythrocytes, they did not affect the viability of the splenic lymphocytes. Suppression was seen when the synthetic preparations were added simultaneously with or after the lipid A mitogen, but optimal suppression was expressed when the preparations were added to the system 3 h before lipid A. Washing of the cells before the addition of lipid A did not affect the results. The suppression was not due to the induction of suppressor cells by the synthetic preparations. The disaccharide preparations did not inhibit T-cell mitogenicity of concanavalin A. In contrast to the disaccharide preparations, the monosaccharide preparations suppressed mitogenicity of both lipid A and concanavalin A, probably because of their direct toxicity for lymphocytes.

Animals↗
PubMed1984

Induction of hyperreactivity to endotoxin in mice by Coxiella burnetii.

Intraperitoneal inoculation of mice with live or killed Coxiella burnetii phase I or phase II cells induced a marked hyperreactivity to the lethal effect of bacterial endotoxin and was accompanied by a marked hepatosplenomegaly. The degree and duration of hyperreactivity depended on the dose of C. burnetii administered and were higher with phase I than with phase II cells. Sensitization to the lethal effects of endotoxin and induction of splenomegaly by phase I C. burnetii cells also proceeded in the endotoxin-resistant C3H/HeJ strain of mice. Preincubation of C. burnetii cells with the corresponding immune serum significantly diminished the ability of phase I but not phase II cells to induce hyperreactivity to endotoxin.

Animals↗
PubMed1984

Generation of slow-reacting substance (leukotrienes) by endotoxin and lipid A from human polymorphonuclear granulocytes.

Leukotrienes were released from human polymorphonuclear granulocytes on incubation with endotoxins and lipid A. The analysis was performed by their smooth muscle contracting properties, reversed phase high-pressure liquid chromatography and radioimmunoassay for leukotrienes C4 and D4. The active component of the lipopolysaccharides seems to be the lipid A portion.

Biological Assay↗
PubMed1983

A method to detect 2-keto-3-deoxyoctanat and related compounds on pherograms and chromatograms.

A variation of the thiobarbituric acid spray reagent to detect 2-keto-3-deoxyoctanat (KDO), KDO derivatives, 2-deoxysugars, and N-acetylneuraminic acid on pherograms and chromatograms is described. Using all reagents in organic solvents and developing the color at room temperature, accurate locations of the spots without spreading and a low background stain are achieved.

Chromatography, Thin Layer↗
PubMed1983

Isolation of a 3-deoxy-D-mannooctulosonic acid disaccharide from Salmonella minnesota rough-form lipopolysaccharides.

Lipopolysaccharides of Salmonella minnesota rough mutants were treated with 20 mM acetate buffer pH 4.4 at 70 degrees C/3 h. After dialysis of the hydrolysates about one third of the total 3-deoxy-D-mannooctulosonic acid (dOclA) content but no neutral sugars were found in the dialysate. By high-voltage paper electrophoresis, a compound with the mobility of 1.2 relative to dOclA could be isolated from the dialysate. It was identified as a dOclA disaccharide by hydrolysis without or after reduction with sodium borohydride and by analysis with the thiobarbituric acid assay under different conditions. The ketosidic linkage in the disaccharide is assumed to be 2.4 or 2.5.

Disaccharides↗
PubMed1983

A new lipopolysaccharide antigen identified in Acinetobacter calcoaceticus: occurrence of widespread natural antibody.

Serological investigation of the lipopolysaccharide (LPS) of Acinetobacter calcoaceticus revealed a new antigen to which antibody in high titre is present in the serum of many mammalian species. The passive haemolysis test showed that antibody, in titres ranging from 32-4096, was invariably present in the serum of mice, rats, guinea-pigs, and horses. Rabbits and human beings had lower and more variable titres (less than 2-512). The antigen persisted after prolonged hydrolysis of the LPS in 1% acetic acid at 100 degrees C. Acinetobacter lipid A, which resembled antigenically the lipid A of many gram-negative bacteria, could be distinguished from the new antigen by inhibition and absorption experiments. Antibody to the new antigen could be completely absorbed with acinetobacter lipid A but not with enterobacterial lipid A; moreover, the latter failed to react with the antibody in the passive haemolysis test. Immunisation of rabbits with lipid A-immunogenic acinetobacter cells gave rise to antibodies against the new antigen and to lipid-A antibodies. Absorption of the immune serum with acinetobacter lipid A removed antibody to both antigens, but absorption with enterobacterial lipid A removed only the lipid -A antibodies.

Acinetobacter↗
PubMed1983

Common lipopolysaccharide specificity: new type of antigen residing in the inner core region of S- and R-form lipopolysaccharides from different families of gram-negative bacteria.

A new antigenic specificity, referred to here as common lipopolysaccharide (LPS) specificity, is described in the LPSs of gram-negative bacteria belonging to various families. The specificity is present in S- and R-form LPS but absent in Re mutants of different enterobacterial genera. By the use of purified LPS and monospecific antibodies obtained by immunoabsorption, the specificity is differentiated from the known core specificities of the genus Salmonella and the lipid A specificity by aid of the passive hemolysis and passive hemolysis inhibition test. In Salmonella minnesota R-form LPS, the specificity may be cryptic (R345, Rb2 mutant) or partly exposed in the intact molecule (R7, Rd1 mutant). The specificity is either demasked or completely exposed after mild acid hydrolysis for a short time, whereas it is destroyed after prolonged hydrolysis. Periodate oxidation, reduction, and hydrolysis under conditions that do not affect the ketosidic linkages of 2-keto-3-deoxyoctulosonic acid destroy the specificity in R4 (Rd2 mutant) LPS, but do not do so in R7 LPS. It is suggested that 2-keto-3-deoxyoctulosonic acid and a following neutral sugar are the compositional requirements for expressing the specificity.

Bacteroidaceae↗
PubMed1983

Nontoxic lipopolysaccharide from Rhodopseudomonas sphaeroides ATCC 17023.

Chemical analysis of the lipopolysaccharide from Rhodopseudomonas sphaeroides ATCC 17023, isolated by the phenol-chloroform-petroleum ether method, revealed the presence of glucuronic acid, 2-keto-3-deoxyoctonate, threonine, and phosphorus in the polysaccharide moiety. The lipid A component contained glucosamine, glucosamine phosphate, amide-bound 3-oxotetradecanoic acid and 3-hydroxytetradecanoic acid, and ester-bound 3-hydroxydecanoic acid and 7-tetradecenoic acid. Structural similarity of the lipid A from R. sphaeroides ATCC 17023 to enterobacterial lipid A is indicated by the existence of a serological cross-reaction occurring between the lipid A from R. sphaeroides ATCC 17023 and that from Salmonella minnesota R595. The lipopolysaccharide and lipid A of R. sphaeroides, however, were found to be neither toxic in mice nor pyrogenic in rabbits.

Carbohydrates↗