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PubMed1981

Reducing the endotoxic activity of pertussis vaccine.

Unadsorbed, regular production pertussis vaccine was treated with polymyxin B sulphate at concentrations of 25, 50 and 100 microgram/ml. The toxic activity of treated and untreated vaccines was compared using both the limulus amoebocyte lysate test and the mouse-weight-gain test. Protective efficacy was also assessed by the mouse protection test. No discernible effect on either toxicity or efficacy of the pertussis vaccine was observed. When the vaccine was treated with 5000 microgram/ml of polymyxin, endotoxic activity assessed by the limulus lysate test appeared to be abolished.

Animals↗
PubMed1987

Presence of circulating endotoxins during cardiac operations.

Ten patients having coronary artery bypass grafting were intraoperatively and postoperatively analyzed for endotoxins with the Limulus amoebocyte lysate test. A new highly sensitive rocket immunoelectrophoretic assay for reading the reactions of endotoxins with Limulus amoebocyte lysate was used. Preoperatively, all blood samples from the patients had negative Limulus amoebocyte lysate tests, negative blood cultures, normal total white cell counts, and were clinically without signs of infection. Intraoperatively, a substantial amount of endotoxins were found in samples from the extracorporeal circuit, the pulmonary artery, and the cardiac suction lines, which persisted during the cardiopulmonary bypass. The endotoxin content decreased significantly (p less than 0.05) 6 hours after cardiopulmonary bypass and further decreased within the seventh postoperative day (p less than 0.01). A positive Limulus amoebocyte lysate test was also found in some of the fluids administered during the operation, that is, the cardioplegic fluids, the priming fluids for the extracorporeal circuit, the blood transfusions, and the ice for local cooling. Postoperatively, all patients had rectal temperatures below 38.5 degrees C, but no correlation was found between the magnitude of endotoxin content and the degree of fever. Only one of the patients had positive blood cultures. Despite the measured endotoxin content, no intraoperative or postoperative complications were found.

Aged↗
PubMed1977

Antigens of Haemophilus influenzae.

Three antigenic preparations were obtained from a non-capsulated strain of Haemophilus influenzae by ultrasonic disintegration, hot phenol extraction and from a fluid culture. They were designated H. influenzae cytoplasmic antigen (H(1-5); H. influenzae cell wall antigen (HCW); and H. influenzae culture filtrate antigen (HCF). Studies showed that H(1-5) antigen contained heat stable and heat labile components. The heat stable fraction stained positively for polysaccharide, had a positive limulus lysate test and there was immunological cross-reactivity between this and heat stable fractions of HCW and HCF. Limulus lysate assay indicated the presence of endotoxin in HCW and HCF preparations. Heat stable as well as heat labile antigens of H. influenzae should be given consideration in future studies regarding the pathogenicity of this organism in the lower respiratory tree. The specificity of the heat stable antigen of H. influenzae needs to be determined.

Antibodies, Bacterial↗
PubMedDate not supplied

Disturbing GTP-binding protein function through microinjection into the visual cell of Limulus.

We have tested the action of three agents microinjected into the ventral nerve photoreceptor of Limulus on the electrical response to dim light. 1. A monoclonal antibody (mAb 4A) against the G alpha subunit of frog transducin reduces the size of the receptor current to 60%, suggesting an interaction with G alpha in the Limulus photoreceptor. 2. Injection of Clostridium botulinum ADP-ribosyltransferase C3 reduces the size to 46%; latency is not affected. The results imply that small GTP-binding proteins play a functional role in photoreception of invertebrates. 3. Injection of GDP-beta-S reduces dose-dependently the size of the receptor current to 15% and prolongs the latency to 200%, presumably by reducing number and rate of G-protein activations.

Animals↗
PubMed1987

Endotoxin testing in blood.

A chromogenic assay is presented for the determination of endotoxin (LPS) in blood. The assay is based upon the LPS-dependent activation of Limulus amebocyte lysate (LAL), and the subsequent measurement of the activated enzyme with a chromogenic substrate. Handling and stability of the reagents, details of the assay method in tubes or microtiter-plates, recovery of LPS from spiked blood in platelet-rich plasma (PRP), platelet-poor plasma (PPP) and serum, as well as the possibility to store plasma samples will be discussed. A clinical evaluation of the assay is provided by S. van Deventer et al. in this volume.

Chromogenic Compounds↗
PubMed1986

Lack of interference in skin tests by endotoxin in allergen extracts.

Endotoxin activity was detected in several commercial allergen extracts. Epicutaneous skin testing using purified lipopolysaccharide (LPS) alone or mixed with allergen extracts demonstrated that LPS had no effect on test results. We conclude that endotoxin present in allergen extracts is unlikely to have any practical implication for epicutaneous skin testing with these extracts.

Allergens↗
PubMed1985

Alterations in rats in vivo of the chemical structure of lipopolysaccharide from Salmonella abortus equi.

A biosynthetically double-labelled lipopolysaccharide (LPS) from Salmonella abortus equi was used to study possible in vivo degradation of LPS in rats. The preparation designated rLPS-I was labelled with 3H in the fatty acids and 14C in the sugars. Three days after its intravenous injection the concentration of the two isotopes in the liver was analysed directly by combustion of liver tissue in a sample oxidizer. It was found that compared to the starting LPS, less 3H activity was present than 14C, indicating that partial deacylation had occurred. Reisolation and purification of radioactive material present in the liver revealed that all radioactivity was present in a macromolecular form. Analysis showed that the ratio of the two isotopes was identical to that determined in the starting liver tissue. To exclude the possibility that the loss of 3H might have been due to isotopic dilution the above experiments were repeated with a second LPS preparation (rLPS-II) labelled with 14C in the fatty acids and 3H in glucosamine. Isotopic analysis confirmed that here too a lower content of fatty acids in the LPS was present in the liver. A large-scale (20 rats) reisolation of non-radioactive LPS of S. abortus equi from rat livers three days after injection was carried out. Chemical analysis revealed the presence of 3-deoxy-D-manno-octulosonic acid, heptose, galactose, mannose and rhamnose in a molar ratio similar to that of the original LPS. However a significant reduction in the amount of abequose was found. Fatty acid analysis showed a significant reduction in the content of 3-hydroxytetradecanoic, dodecanoic and hexadecanoic acids, while 2-hydroxytetradecanoic acid was virtually absent. Only the relative amount of tetradecanoic acid was comparable to that of the starting LPS. Biological activity tests on the reisolated material showed a reduced antigenic activity. However, pyrogenicity, lethal toxicity, local Shwartzman-inducing properties and Limulus lysate gelating activity were comparable to the starting S. abortus equi LPS.

Animals↗
PubMed1997

[Use of the LAL test for quantitative determination of Bacteroids fragilis endotoxin].

The aim of this study was the evaluation of LAL test with chromogenic substrate usefulness for the quantitative detection of B. fragilis endotoxin and the determination of the amount of endotoxin in culture filtrates of the strains of this species. Also, the trial was undertaken to determine the influence of clindamycin on endotoxin release from B. fragilis rods to the culture medium. Four B. fragilis strains were examined: one nonenterotoxigenic (NTBF) and three enterotoxigenic (ETBF). The growth of cultures was determined and endotoxin liberated to the culture medium during growth of strains was detected. BHI broth and BHI broth with addition of sub inhibitory doses (sub-MIC) of clindamycin were applied. Bacterial cultures were incubated for 48 hours at 37 degrees C. Samples of bacterial cultures were collected after 4, 8, 16, 24 and 48 hours of cultivation, and the optical density was measured. Then the samples were centrifuged, supernatants were filtered through 0.45 micron filters and concentrated three times with 5000 D ultrafilters. Prepared samples were kept frozen at -70 degrees C until used. The amount of endotoxin in samples was determined using quantitative LAL test with chromogenic substrate S-2423. The results of the experiments indicate that LAL test is the useful method for determination of B. fragilis endotoxin concentration. This endotoxin activates the enzymatic system present in Limulus polyphemus amebocyte lysate. Endotoxin is shed spontaneously by B. fragilis rods to the culture medium during growth. Clindamycin at subinhibitory concentrations (sub-MIC) inhibits the growth of cultures of examined strains. The antibiotic caused increase in endotoxin amount in culture medium.

Bacteroides fragilis↗
PubMed1980

Relative potencies of four reference endotoxin standards as measured by the Limulus amoebocyte lysate and USP rabbit pyrogen tests.

Four commonly used reference endotoxin standards, Escherichia coli O113:H10:K0, E. coli O55:B5, Salmonella abortusequi, and Shigella dysenteriae were compared by the USP rabbit pyrogen and the Limulus amoebocyte lysate tests. By the rabbit pyrogen test, S. abortus equi was identified as the most potent endotoxin, followed closely by E. coli O113:H10:K0 and E. coli O55:B5.

Animals↗