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PubMed2003

The generalized endotoxic principle.

Bacterial lipopolysaccharides (endotoxins, LPS) belong to the most potent immunostimulators in mammals. The endotoxic principle of LPS is located in its lipid A moiety, which for Escherichia coli-type LPS consists of a hexaacylated diphosphoryl diglucosamine backbone. This lipid A adopts a cubic inverted aggregate structure from which a conical shape of the molecule can be deduced, whereas the tetraacyl lipid A precursor IVa adopts a cylindrical shape and is endotoxically inactive, but antagonizes active LPS. We hypothesize that non-lipid A amphiphiles with similar physicochemical properties of amphiphilicity, charge, and shape, might mimic the respective lipid A. To test this hypothesis, phospholipid-like amphiphiles with six acyl chains attached to a bisphosphorylated serine-like backbone of varying length replacing the diglucosamine backbone were synthesized. The compound with a short backbone fulfills all criteria of an endotoxic agonist, and that with long backbone fulfills those of an antagonist. This holds true for the human as well as for the murine system. Interestingly, these compounds are inactive in the Limulus amebocyte lysate test which is specific for LPS diglucosamine backbone. These results define a general endotoxic principle and, furthermore, provide new insights into an understanding of early steps of endotoxin action.

Adult↗
PubMedDate not supplied

Aspergillus peritonitis in continuous ambulatory peritoneal dialysis patients.

Aspergillus peritonitis is a rare and serious cause of peritonitis in continuous ambulatory peritoneal dialysis (CAPD) patients. We report 3 cases of aspergillus peritonitis in CAPD which were successfully treated by catheter removal and amphotericin. Two of the 3 patients returned temporarily to CAPD, but were subsequently transferred to hemodialysis because of membrane failure. A novel finding in 2 of the 3 cases was a positive Limulus amebocyte lysate test, despite negative bacterial cultures. We discuss the possible relevance of this finding to the diagnosis of aspergillus infections and emphasize the importance of early catheter removal for successful treatment of this condition.

Aged↗
PubMed1982

The potential value of endotoxin-amylase detection in peritoneal lavage fluid.

Widespread acceptance of Limulus Amoebocyte Lysate testing in clinical situations has been elusive. The results obtained in this series of 38 patients seem to support the contention that the amylase-endotoxin complex can be of value in detecting rapidly and with reasonable sensitivity the presence of pancreatic injury and gastrointestinal perforations. A corrected WBC count appears to add diagnostic possibilities to the technique. Despite the promising evidence detailed in this paper, further studies are required to establish the true sensitivity/specificity of the test. Its validity and utility could be assessed rapidly if traumatologists who routinely perform lavage would utilize this method and report their findings.

Abdominal Injuries↗
PubMed1991

Importance of endotoxins in high-flux dialysis.

Endotoxins are not only important for inducing pyrogenic reactions during haemodialysis but also for the stimulation of different blood cells. This is followed by the release of interleukin-1 and other powerful biological active substances, resulting in a broad spectrum of biological activities. Permeation of LPS (endotoxins) through dialysis and haemofiltration membranes is of great importance. Using a quantitative turbidimetric method based on the LAL (limulus amoebocyte lysate) test LPS concentrations were measured in a closed in vitro system for 11 different dialysers and haemofilters. To assess the passage of endotoxin through the membrane, permeation was measured from the dialysate to the blood side as well as from the blood compartment to the dialysate side.

Endotoxins↗
PubMed1994

[The inhibitory effect of mouse monoclonal IgM antibody E5 against endotoxin on limulus activity of various lipopolysaccharides].

The anti-endotoxin activity of mouse monoclonal IgM antibody E5 was determined against various lipopolysaccharides (LPSs) derived from Escherichia coli J5, E. coli O111:B4, Klebsiella pneumoniae and Pseudomonas aeruginosa by measuring limulus activity by endospecy method. In general, above 0.2 microgram/ml of E5 reduced almost dose-dependently the limulus activities of all LPSs tested, although the degree of reduction in limulus activity somewhat varied among bacterial species. The limulus activities of LPS from E. coli J5, E. coli O111:B4, K. pneumoniae and P. aeruginosa decreased by 72%, 50%, 44%, and 58%, respectively, by exposure to 5.0 micrograms/ml of E5 for 2 hrs.

Animals↗
PubMed1979

Statistical procedure for evaluating the sensitivity of Limulus amoebocyte lysate by using a reference lysate.

A study was designed to estimate variability of the Limulus amoebocyte lysate test by comparing a reference lysate against itself. Three technicians performed parallel tests, i.e., titrated side by side, the contents of two vials of reference lysate on 4 different days using 24 vials of the United States reference lysate and 12 vials of the United States reference endotoxin. Each parallel test was replicated three times. From the sensitivity endpoints, ratios were calculated for each parallel test. These ratios were converted to the logarithm for estimating variability among technicians and among vials of endotoxin. By using the overall variability of log ratios, a statistical procedure was developed to evaluate the sensitivity of each lot of licensed lysate submitted to the Bureau of Biologics for release.

Endotoxins↗
PubMed1987

[Postoperative endotoxin determination and immunoglobulin therapy of infected patients in the intensive care unit].

Seventy-four patients with septic postoperative complications were prospectively listed. Plasma-borne endotoxin was daily determined in all of them by means of the limulus-amoebocyte-lysate test. Maximum sensitivity of the test amounted to 64 per cent, related to days of illness due to severe septicaemia. The conclusion is drawn that additional parameters should be used in future studies to define sepsis, including determination of sepsis score. Endotoxin titres declined in response to immunoglobulin therapy. Lethality went down, as well.

Adolescent↗
PubMed1978

Role of lipopolysaccharide in the production of plasma cell tumors in mice given mineral oil injections.

The lipopolysaccharide (LPS) content of peritoneal fluids of BALB/c mice given mineral oil injections and of normal mice was measured. Peritoneal fluids were passed through DEAE-Bio-Gel columns to remove an inhibitor to the Limulus amebocyte lysate reaction and then were assayed for LPS by a spectrophotometric Limulus amebocyte lysate test. A highly significant difference between control animals and animals given mineral oil injections was found. A clear correlation between LPS concentration and time after first oil injection was shown. P-200 gel chromatography and heat stability of the active material were consistent with the behavior of LPS. The possible role of LPS in the pathogenesis of plasma cell tumor is discussed.

Animals↗
PubMed1981

Endotoxemia following experimental intestinal strangulation obstruction in ponies.

Experimental small intestinal strangulation obstruction was produced in anesthetized ponies. The limulus amoebocyte lysate test demonstrated the presence of endotoxin in the general circulation 60 and 120 minutes following restoration of mesenteric blood flow. Mucosal degeneration, with loss of villus epithelial cells, was demonstrated coincident with endotoxemia. The findings were consistent with an ischemia-mediated alteration in the intestinal barrier to endotoxin.

Animals↗
PubMed1989

Effects of different extraction protocols on endotoxin analyses of airborne grain dusts.

The detection of gram-negative bacterial endotoxins in occupational dusts, specifically those from agricultural environments, is of increasing importance in research on occupational lung disease. In this study, the quantitative chromogenic Limulus amebocyte lysate test for the detection of endotoxins in airborne dusts from spring wheat and oats was examined. Different extraction fluids were tested, as were the effects of time on extraction and of repeated freeze-thaw cycles on the extracts. The data suggest that the chromogenic method can be used effectively in the analysis of environmental dusts or their frozen extracts for endotoxin quantitation. Water appears to be the preferable extraction medium, and the length of extraction time may affect the results.

Dust↗
PubMed1982

Studies on the pathogenesis of the Jarisch-Herxheimer reaction: development of an animal model and evidence against a role for classical endotoxin.

The etiology of the Jarisch-Herxheimer reaction is unknown, but the reaction may result from toxic products of dead or dying treponemes reacting with sensitized syphilitic tissues. Because of similarities of spirochetes with gram-negative bacteria, endotoxin has been proposed as the responsible toxin. In 19 patients with syphilis, a reaction occurred in 15 (79%) during treatment with penicillin. Endotoxemia was not found by the limulus amoebocyte lysate test. All animal model of the Jarisch-Herxheimer reaction was developed in rabbits infected with Treponema pallidum. When treated with penicillin, 18 (78%) of 23 rabbits infected 18-29 days previously developed a reaction that resembled that in humans. Endotoxemia was not detected by the lysate test. After the reaction, rabbits were not refractory to the pyrogenic effects of endotoxin, and syphilitic rabbits rendered tolerant to endotoxin still developed fever when treated with penicillin. These data suggest that classical endotoxin is not the cause of the Jarisch-Herxheimer reaction.

Adult↗
PubMed1980

The appearance of endotoxin following urethral instrumentation.

The Limulus amoebocyte lysate test was used to detect the presence of endotoxin in the venous blood of 10 patients following urethral instrumentation. The test was negative in all patients before instrumentation, became positive in 9 immediately after instrumentation and in 1 30 min after instrumentation. In 6 patients endotoxin reappeared between 1.5 h and 4.5 h after instrumentation. All blood samples, cultured aerobically and anaerobically, were sterile. Escherichia coli were cultured from one midstream specimen of urine and from one urethral swab in the same patient taken before instrumentation. There were no significant changes in either pulse rate or axillary temperature following instrumentation.

Aged↗
PubMed1980

Endotoxemia of cirrhosis: an observation not substantiated.

Physiologic similarities between cirrhotic and septic patients have implicated systemic endotoxemia as a possible mediator of the hemodynamic, neurologic, and hematologic complications observed in patients with cirrhosis of the liver. The recently reported high prevalence of endotoxin in ascites, as well as in portal and systemic plasma, has further incriminated endotoxin of gut origin as the responsible agent. Limulus amebocyte lysate tests were performed upon peripheral plasma of 38 cirrhotic patients; portal plasma and ascites were assayed in 14 and 11 of these patients, respectively. No endotoxin was detectable. We believe that the ubiquity of endotoxin, with the attendant opportunities for specimen contamination, is the most likely explanation for the recently reported high prevalence of endotoxin in the plasma and ascites of cirrhotic patients.

Adult↗
PubMed2003

[Studies on antiendotoxin action of total saponins from radix Bupleuri].

OBJECTIVE: To study antiendotoxin activities of total saponins from Radix Bupleuri. METHOD: The antiendotoxin activities were demonstrated by Limulus Amebocyte Lysate test (LAL test) in vitro, the fever model induced by endotoxin in rabbits and the model induced by LPS in BCG-primed mice. RESULTS: Total saponins from Radix Bupleuri still had antiendotoxin effect even when it (50 mg.ml-1) was diluted to 32 times by LAL test in vitro. The fever experiment results showed the average rising temperature of BCS + LPS, group, model group and BCS group was 0.75 degrees C, -0.25 degrees C and -0.37 degrees C respectively. In the experiment of the poison induced by LPS, fatal rate of model group was 90.0%, that of BCS + LPS group was 13.3%, there was a significant difference (P < 0.01). CONCLUSION: The result showed that the total saponins in Bupleuri had the strongest antiendotoxin action.

Animals↗
PubMed1991

Chylomicrons can inhibit endotoxin activity in vitro.

Trauma, thermal injury, and nonlethal doses of endotoxin can promote the translocation of endotoxin across the mucosal barrier of the colon into the mesenteric lymphatics and systemic circulation. Bacterial endotoxemia induces changes in lipid metabolism, including an increase in circulating triglyceride-rich lipoproteins. Because cholesterol-rich lipoproteins can neutralize the toxic activity of endotoxin, both in vitro and in vivo, we asked whether triglyceride-rich chylomicrons can inhibit endotoxin activity in vitro as measured by a chromogenic Limulus assay. We tested the effect of intact versus heat-denatured chylomicrons on the in vitro activity of increasing concentrations of Escherichia coli (055:B5) endotoxin. Intact chylomicrons inhibited up to 12-fold the detection of as much as 1 microgram of endotoxin/mg of chylomicron triglyceride, compared to denatured chylomicrons (P less than 0.001). This study shows that chylomicrons are potent inhibitors of endotoxin activity in vitro. Because translocated endotoxin from the colon associates with gut-derived chylomicrons in the mesenteric lymphatics, this may represent a natural defensive mechanism against endotoxemia of enteric origin.

Chylomicrons↗
PubMed1990

Endotoxins in cardiopulmonary bypass.

Endotoxins are biologically active substances derived from the cell wall of degraded gram-negative bacteria. Since sterile water may also contain large amounts of endotoxins, these are easily introduced into the manufacturing processes of technical medical material, such as the extracorporeal components used in cardiopulmonary bypass. In hemodialysis, the presence of endotoxins has been related to untoward effects in patients. Using the limulus amebocyte lysate test, we determined the serum concentration of endotoxin in 42 patients undergoing coronary bypass operations. The values increased during cardiopulmonary bypass, exceeding the normal range of 0 to 20 ng/L in 10 patients with a maximum of 82 ng/L, which probably indicates endotoxin release from the extracorporeal equipment. We found no obvious relation to postoperative morbidity. The endotoxin levels of this study are considerably lower than those reported in two other studies of patients having cardiopulmonary bypass. This might be due to less intraoperative contamination but possibly also to differences in analytic methods.

Adult↗
PubMed2003

Lipopolysaccharide concentration and bone resorption in cholesteatoma.

HYPOTHESIS: There is a relationship between the local lipopolysaccharide (LPS) concentration in cholesteatoma and local bone resorption in chronic otitis media (COM) with cholesteatoma. BACKGROUND: During the past decade, it has become known that the recruitment of osteoclasts is the main causative factor that induces bone destruction in COM with cholesteatoma. Cellular inflammation factors like cytokines may trigger the osteoclast. Sequel to this, LPS is able to up-regulate cytokines. This makes it of interest to study whether the local LPS concentration is related to bone resorption in cholesteatoma. MATERIALS AND METHODS: Twenty-four cholesteatoma samples and control tissue from COM patients without cholesteatoma were collected. During surgery, the degree of bone resorption was established and classified. Retrospectively, the authors checked whether patients had chronic purulent otorrhea. LPS concentration of the tissue samples was measured by the limulus amebocyte lysate test. The one-way analysis of variance test was used to determine the relation between LPS concentration, otorrhea, and local bone resorption. RESULTS: A significantly higher concentration of LPS was measured in samples from patients with cholesteatoma with bone resorption and otorrhea compared with cholesteatoma without bone resorption and control tissue. There were no significant differences between the LPS levels of the different groups of patients with bone resorption. CONCLUSION: It is suggested that LPS is one of the first factors in the cascade of bone resorption in COM with cholesteatoma.

Bone Resorption↗