Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Limulus Test”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 451 records · Page 25Linked to original sources
PubMed1977

Endotoxin and bacteria in portal blood.

In order to determine whether endotoxin is normally found in the portal system, intraoperative samples of portal and peripheral blood were drawn from 34 consecutive elective abdominal surgery patients. The limulus lysate test was used to detect endotoxin. Ninety-seven per cent of patients had a positive limulus test in portal blood. Twelve of these patients were tested for portal bacteremia and only one showed growth. Four patients also had systemic endotoxemia. Three of these had liver disease and one had a gram-negative sepsis. This study demonstrates that endotoxin is a normal constituent of portal venous blood in man and does not represent a pathological process. It is suggested that the Kupffer cells of the liver normally protect the systemic circulation from endotoxin, and that endotoxin is present in systemic blood only when liver function is impaired or gram-negative bacteremia is present.

Adenocarcinoma↗
PubMed1980

Endotoxin-like activities of mycoplasmal lipopolysaccharides (lipoglycans).

Lipoglycans (previously designated lipopolysaccharides) from several species of Acholeplasma and from Thermoplasma acidophilum were examined for endotoxin-like activities as measured by the standard rabbit fever test and the Limulus amoebocyte lysate assay. The lipoglycans from Acholeplasma granularum, Achloplasma laidlawii, Acholeplasma modicum, and Acholeplasma oculi caused a febrile response at concentrations of 1 ng/ml per kg or greater, whereas with control Escherichia coli EC-2 lipopolysaccharides, 6.25 ng/ml per kg was required. Similar results were obtained in the Limulus amoebocyte lysate test. The minimum concentrations in nanograms per milliliter required to stimulate formation of a solid clot were: Acholeplasma axanthum, 0.22; A. granularum, 0.85; A. modicum, 0.51; A. laidlawii, 1.05; A. oculi, 0.74. Standard E. coli 1B lipopolysaccharide required a concentration of 0.125 ng/ml. Thermoplasma lipoglycan was least active, requiring 4.25 ng/ml. Clotting of the Limulus lysate proceeds by the activation by lipopolysaccharide plus Ca(2+) of a proenzyme which cleaves an arginine-lysine peptide bond of the coagulogen. The clotting and amidase activities are inactivated by deoxycholate and can be reactivated by addition of lipopolysaccharide and Ca(2+). As with E. coli 1B lipopolysaccharide, acholeplasmal lipoglycans were shown to restore both clotting and amidase activities of the deoxycholate-inactivated Limulus clotting enzyme. The degree of restoration of amidase activity by mycoplasmal lipoglycans relative to E. coli lipopolysaccharide (1.00) were: A. axanthum, 1.71; A. modicum, 1.22; A. granularum, 0.61; and Thermoplasma, 0.37. The coagulating enzyme, restored with either E. coli lipopolysaccharide or mycoplasmal lipoglycans, was able to react with the synthetic peptide benzoyl-Ile-Glu-(gamma-OCH(3))-Gly-p-nitroaniline (an analog of the coagulogen) or with the purified coagulogen itself to form the clot. The mycoplasmal lipoglycans alone were incapable of promoting these reactions when incubated with the synthetic peptide or with the purified coagulogen, thereby ruling out the contamination of these lipoglycans with proteases capable of cleaving the same Arg-Lys peptide bond of the coagulogen. These results show that acholeplasmal lipoglycans possess endotoxin-like activities. Their passive or active role in disease remains to be established.

Acholeplasma↗
PubMed1985

The design of a reliable endotoxin test.

An endotoxin assay utilizing Limulus lysate (LAL) and a chromogenic peptide substrate is described. The assay of picograms of a compound, present in significant quantities almost everywhere, is obviously associated with a serious risk of contamination. Measures to avoid and detect contamination have been considered. When a quantitative assay like the present one is used, the inhibitory effects of samples analyzed are obvious and also possible to quantify. Methods to avoid such inhibitory effects have been studied and the simplest procedure seems to be dilution with endotoxin-free water, in some cases also combined with heat treatment (75 degrees C for 5 min).

Animals↗
PubMed2003

[The current status of the determination of the bacterial endotoxin in traditional Chinese medicine].

OBJECTIVE: To review the current status of the determination of the bacterial endotoxin in traditional chinese medicine injections with the limulus lysate test, and to evaluate the feasibility of this test for the determination of the bacterial endotoxin in these injections. METHOD: The data related to the topic was collected, analyzed and summarized. RESULT: The limulus lysate test was not available for most of traditional chinese medicine injections due to the interference. And the same injection may uield different test results because of different factories, batch numbers, different techniques and preparational conditions. CONCLUSION: There is still a long way to go to apply the limulus lysate test to the determination of the bacterial endotoxin in traditional chinese medicine injections.

Drugs, Chinese Herbal↗
PubMed1980

Hypocomplementemia and Campylobacter fetus infection.

A middle-aged alcoholic man had low C3 levels during two consecutive episodes of bacteremia with Campylobacter fetus, with a return of C3 levels to normal during the interbacteremic period. Total complement levels remained below normal throughout the patient's illness, whereas C4 and C3 activator values were in the normal or supranormal range. A rise and fall in hemagglutinating antibody titers, documenting an immune response, coupled with reasonable antimicrobial therapy were not sufficient to prevent the development of chronic infection. It is suggested that complement may play an important role in the pathogenesis of C fetus infections.

Adult↗
PubMed1994

Free hydroxyl groups are not required for endotoxic activity of lipid A.

Previous studies demonstrated that lipid A from Salmonella abortusequi loses its B-cell mitogenicity for murine spleen cells as a result of the introduction of succinyl residues on hydroxyl groups and that the inactivated lipid A specifically antagonizes the mitogenicity of endotoxin. Hypothesizing that the hydroxyl groups are essential both for its biological activity and for producing nontoxic preparations having antagonistic activity, I tested the role of the hydroxyl groups in its activities by using well-characterized biologically active lipid A preparations synthesized chemically (Escherichia coli and Salmonella types 506 and 516, respectively) by the introduction of either succinyl or acetyl residues at the hydroxyl groups of each of these lipid A preparations. However, the biological activities of neither lipid A preparation were reduced at all after succinylation; in fact, succinylated 516 became much more potent than the original molecule with respect to most activities tested, i.e., lethal toxicity, Limulus gelation activity, and the induction of tumor necrosis factor release. On the other hand, when the hydroxyl groups were replaced with acetyl residues, the lethality and tumor necrosis factor-inducing activity of both lipid A preparations were decreased, whereas their Limulus gelation activity was increased. Mitogenicity was not affected much by the chemical modifications of either lipid A preparation. These findings indicate that although the residues introduced into the free hydroxyl groups of lipid A modulate its activities, the hydroxyl groups in lipid A need not exist in free form.

Animals↗
PubMed2002

Systemic release of endotoxins induced by gentle mastication: association with periodontitis severity.

BACKGROUND: Periodontitis has recently been identified as a potential risk factor for systemic pathologies such as cardiovascular disease, the hypothesis being that periodontal pockets could release pro-inflammatory bacterial components, for instance endotoxins, into the bloodstream. It is known that the oral cavity can be a source of circulating bacteria, but this has never been shown for bacterial endotoxins, and no evidence exists so far that the risk of systemic injury is related to the severity of periodontitis. The aim of the present study was to test the influence of gentle mastication on the occurrence of endotoxemia in patients with or without periodontal disease. METHODS: A total of 67 subjects were periodontally examined and grouped according to their periodontal status. This classification was based on an original index of severity of periodontal disease (periodontal index for risk of infectiousness, PIRI) aimed at reflecting the individual risk of systemic injury from the periodontal niches. Thus, the patients were classified into 3 risk groups: low, PIRI = 0; n = 25; moderate, 1 < or = PIRI < or = 5, n = 27; and high 6 < or = PIRI < or = 10, n = 15. Blood samples were collected before and 5 to 10 minutes after a standardized session of gentle mastication for detection of circulating endotoxins. Blood samples were tested with a chromogenic limulus amoebocyte lysate assay. RESULTS: Overall, blood levels of endotoxin after mastication were found to be significantly higher than before mastication (0.89 +/- 3.3 pg/ml versus 3.0 +/- 5.8 pg/ml; P= 0.0002). Likewise, the incidence of positive endotoxemia rose from 6% before mastication to 24% after mastication (P = 0.001). When accounting for the PIRI index, endotoxin levels and positive endotoxemia proved to be significantly higher in patients with severe periodontal disease than in the subjects with low or moderate periodontitis. CONCLUSIONS: Gentle mastication is able to induce the release of bacterial endotoxins from oral origin into the bloodstream, especially when patients have severe periodontal disease. This finding suggests that a diseased periodontium can be a major and underestimated source of chronic, or even permanent, release of bacterial pro-inflammatory components into the bloodstream.

Adult↗
PubMed1978

Liberation of endotoxin during growth of Neisseria meningitidis in a chemically-defined medium.

Modified medium 199 is well suited to the growth of meningococci if rich growth is not necessary. The bacteria were very sensitive to changes in pH and needed a good buffer capacity of the medium. Four strains of Neisseria meningitidis were studied. After the stationary phase had been reached, the vital cell count decreased relatively slowly. However, the total cell count remained unchanged for at least 12 hours. The standardized E. coli endotoxin could be detected easily by the Limulus lysate test in different protein-free, pH-adjusted and ion-balanced liquids, and the determination of endotoxin was reproducible. The Limulus lysate test was more sensitive than the rabbit pyrogen test as regards meningococcal endotoxin. Liberation of endotoxin during growth in modified medium 199 varied with strain and growth conditions. Repeated investigations showed the same pattern of growth and endotoxin liberation for each strain, also under other growth conditions. When sonicating the bacteria, high yields of endotoxin were obtained from each strain.

Culture Media↗
PubMed2004

Application of Limulus Amebocyte Lysate (LAL) test for detecting endotoxin (pyrogen) in large volume parenterals.

Screening of twenty five large volume parenterals including dextrose, electrolytes, mannitol, metronidazole infusions, haemodialysis solution, water for injections and distilled water for the determination of pyrogen using Limulus Amebocyte Lysate (LAL) test has been carried out. Out of different preparations only one metronidazole injection exhibited positive LAL test, which was found pyrogen free with USP rabbit pyrogen test.

Journal Article↗
PubMed2000

Bacterial colonization and endotoxin activity during experimental acute fowl typhoid in chickens.

Bacterial colonization and endotoxin production were investigated before and after experimental Salmonella gallinarum infection in 8-week-old female broiler chickens. These parameters were assayed by means of colony forming units test (CFU) and the Limulus Amebocyte Lysate test (LAL), respectively. Birds were infected per os with 1,5 x 10(9) CFU/ml of wild strain of S. gallinarum isolated from a dead hen. Approximately 1,5 x 10(2); 1,3 x 10(2) and 1,2 x 10(2) CFU of S. gallinarum were recorded from 1 g of liver, 1 g of spleen and 1 ml of blood from the chickens on day 1 post infection. By day 4 corresponding data were 3,7 x 10(4); 4,8 x 10(3) and 1,1 x 10(3) respectively and on day 7 10(5) CFU were present in all three specimen types. The liver and spleen of dead birds were contaminated with more than 10(7) CFU per g. The endotoxin from S. gallinarum was found to have an activity of 1,5; 12,0 and 15,0 endotoxin units (EU)/ml on day 1, 4 and 7 after infection, respectively. No endotoxin activity was established in the blood of the control group (before infection) by the LAL test. This is the first time the connection between the amount of live S. gallinarum in the blood, liver and the circulating level of endotoxin in the blood during the infectious stage of experimental acute fowl typhoid, has been demonstrated.

Animals↗