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 1,423 records · Page 79Linked to original sources
PubMed1983

Ability of various adsorbents to bind endotoxins in vitro and to prevent orally induced endotoxemia in mice.

The efficacy of various adsorbents for endotoxin was tested in vitro and in vivo using a murine experimental model of gut-derived endotoxemia. A quantitative limulus amebocyte lysate microtiter test and the limulus amebocyte lysate tube test were used to determine intestinal and circulating levels of endotoxin. Kaopectate, kaolin/pectin mixture, kaolin, pectin, bentonite, charcoal particles, and lactulose were tested for their ability to bind endotoxins both in vitro and in vivo. The most effective material in the prevention of endotoxemia provided to be bentonite followed by Kaopectate and charcoal particles. Kaolin least effectively bound endotoxin at similar concentrations, while lactulose and pectin had minimal effects. Good correlation was shown between the ability of these drugs to bind endotoxin in vitro as compared with in vivo action.

Aluminum Silicates↗
PubMed2004

[The performance of (1, 3)-beta-D-glucan and Aspergillus galactomannan measurement for early diagnosis of invasive aspergillosis in patients with hematological diseases].

We analyzed the performance of (1, 3)-Beta-D-glucan (measurement by the alkaline-kinetic chromogenic Limulus method (FUNGITEC G test-MK, Fungitec) and the kinetic turbidimetric Limulus method [Beta-Glucan test WAKO, Wako]) and we carried out Aspergillus galactomannan antigen detection (enzyme-linked immunosorbent assay, ELISA test) for the early diagnosis of invasive aspergillosis in patients with hematological diseases at the time of febrile episodes of unknown origin that did not respond to antibacterial therapy for more than 3 days. During a one-year period (April 2002 to March 2003), a total of 69 febrile episodes in 58 patients were studied; 8 cases of invasive aspergillosis were diagnosed according to the definition of the European Organization for Research and Treatment of Cancer/Mycosis Study Group, and 61 cases were found to be non-mycotic diseases. Based on the analysis of 69 results with confirmed disease status, the overall performance of the Fungitec, the Wako, and the ELISA test were as follows: sensitivity was 0.88, 0.63, and 0.50, respectively, whereas the specificity was 0.85, 0.98, and 1.0, respectively. Moreover, there was a strong relationship between the log-transformed values of the (1, 3)-Beta-D-glucan levels measured by the two methods (r = 0.92 [95%CI, 0.89-0.94] ; p<0.001). For the statistical analysis of these serological tests a receiver operating characteristic curve (ROC) was used, as well as the resulting area under the ROC curve (ROC AUC). The ROC AUC and the cut-off values that gave the highest accuracy were as follows: 0.92, 24.9 pg/ml for the Fungitec, 0.84, 7.3 pg/ml for the Wako, and 0.89, 0.9 COI for the ELISA test, respectively. In conclusion, these results indicate that both of the two (1, 3)-Beta-D-glucan measurement approaches served equally well as surveillance tools for determining the extent of invasive aspergillosis; in addition, the log-transformed value of these tests can be used for comparison. Moreover, the ELISA test was found to have clinical utility, both as a surveillance and as a diagnostic tool when invasive aspergillosis was suspected. It should be noted that the galactomannan assay had sensitivity-related limitations; lowering the cut-off value is expected to increase the diagnostic value for use in cases of invasive aspergillosis.

Adult↗
PubMed1988

Structural requirements of lipid A species in activation of clotting enzymes from the horseshoe crab, and the human complement cascade.

The structure/activity relationship of lipid A, a bioactive center of endotoxic lipopolysaccharides, in the activation of the clotting enzyme cascade of a horseshoe crab amoebocyte lysate (Limulus activity) and the complement system in human serum, was examined using synthetic lipids A and related compounds. Regarding Limulus activity, a newly developed colorimetric method, which utilizes a mixture of recombined clotting factors and a chromogenic substance, was much more sensitive for detecting changes in the chemical structure of test compounds than the conventional gelation method using the amoebocyte whole lysate. (beta 1-6)-D-Glucosamine disaccharide bisphosphates, which had neither 3-hydroxyacyl nor 3-acyloxyacyl groups, and acylglucosamine phosphates, which in structure correspond or are analogous to the non-reducing or reducing moieties of lipids A and biosynthetic disaccharide lipid A precursors showed only negligible activity in the colorimetric tests, but they exhibited a distinct though much weaker gelation activity than the parent disaccharide molecules. The assay results obtained by the colorimetric Limulus test correlate better with the pyrogenicity of the test synthetic compounds than those given by the gelation method, although the dependence of pyrogenicity on chemical structure is greater. The presence of 3-hydroxyacyl groups on the bisphosphorylated (beta 1-6)-D-glucosamine disaccharide backbone is the prerequisite for effective activation of the clotting enzyme cascade of horseshoe crab amoebocyte lysate, while the presence of an adequate number (one or two) of 3-acyloxyacyl groups on the disaccharide bisphosphate backbone is needed for full pyrogenicity. Complement activation, on the other hand, showed structural requirements quite different from those for the colorimetric Limulus activity and the pyrogenicity. The disaccharide compounds that had only non-hydroxylated acyl groups, acylated glucosamine phosphates that had the structure of the non-reducing portion of lipids A and biosynthetic disaccharide precursors, which were scarcely active in the colorimetric Limulus test, caused complement activation comparable to or sometimes stronger than that of the parent disaccharide molecules. Acylglucosamine phosphates, corresponding in structure to the reducing moiety of disaccharide compounds, however, showed little activity.

Animals↗
PubMed1986

The limulus amoebocyte lysate (LAL) assay--a replacement for the rabbit pyrogen test.

Pharmaceutical products which are to be given by injection are required by law to be sterile and pyrogen-free. This paper outlines some of the advantages and disadvantages of the rabbit pyrogen test. It then covers briefly the history of the development of the Limulus Amoebocyte Lysate assay, followed by the advantages and disadvantages this assay has for use in the pharmaceutical industry.

Endotoxins↗
PubMed1986

Endotoxicity associated with the Lyme disease Borrelia: recent findings.

The endotoxicity of Borrelia burgdorferi, the causative agent of Lyme Disease, a tick-borne spirochetosis, was studied using Limulus assay and pyrogen test in rabbit. Some suspensions of Ixodes ricinus and Ixodes dammini associated Borrelia were able to gelify Limulus lysate and demonstrated a febrile response in rabbit. These findings and other recent data demonstrating an endotoxin-like activity of the Lyme Disease agent are discussed in the context of the pathogenic mechanisms of the illness.

Animals↗
PubMed1996

Vascular reactivity during combined ultrafiltration-hemodialysis: influence of dialysate-derived contaminants.

It has been suggested that hemodynamic instability and impaired vascular reactivity during combined ultrafiltration-hemodialysis are related to bioincompatibility factors such as dialysate-derived contaminants or the dialyzer. The study presented here investigated whether vascular reactivity could be improved by the use of sterile dialysate. Forearm vascular resistance and venous tone (measured by strain-gauge plethysmography) as well as arterial blood pressure (by Dinamap) and heart rate (by electrocardiogram) were measured in ten stable dialysis patients (age range, 28 to 71 yr) during 2 h of combined ultrafiltration-hemodialysis (bicarbonate; ultrafiltration rate 1.0 L/h). In addition, a dialysate sample was obtained for culture and limulus amebocyte lysate testing while blood was withdrawn for the estimation of plasma bactericidal/permeability increasing factor (measured by ELISA) and the soluble tumor necrosis factor receptor p75 (measured by ELISA). Patients served as their own control, comparing dialysis with nonsterile and sterile dialysate. No bacterial growth was observed in sterile dialysate, whereas all samples were positive for Pseudomonas in culture in nonsterile dialysis. All limulus amebocyte lysate tests were negative. Bactericidal/permeability increasing factor tended to increase during nonsterile dialysis (P = 0.063) and remained unchanged during sterile dialysis. In both treatments, tumor necrosis factor receptor p75 increased significantly (P < 0.01). There were no significant differences in hemodynamic parameters between the treatment modalities. Despite use of sterile dialysate, forearm vascular resistance remained unchanged whereas venous tone decreased significantly. These results indicate that vascular reactivity during combined ultrafiltration-hemodialysis is not improved by the use of sterile dialysate.

Adult↗
PubMed1988

Kinetics of endotoxin release by gram-negative bacteria in the intestinal tract of mice during oral administration of bacitracin and during in vitro growth.

The release of endotoxin by gram-negative bacteria was studied during bacitracin-induced intestinal colonization in C3H/Law mice and during in vitro growth. The "free" endotoxin concentration was determined by the Limulus amebocyte lysate test in faecal and in culture supernatants, respectively. After oral administration of bacitracin for 2 days a significant (p less than 0.001) increase of the faecal concentration of gram-negative bacteria of 3-4 logs accompanied a significant (p less than 0.001) increase of the faecal endotoxin concentration from 10(1.8 +/- 0.2) to 10(3.3 +/- 0.2) micrograms endotoxin/g faeces. In vitro, however, an increase of the concentration of gram-negative bacteria of 3-4 logs resulted in a 3-4 log increase of the concentration of endotoxin during the exponential and early stationary growth phase. The faecal endotoxin level after 8 days of bacitracin treatment dropped to a value not significantly different from the initial value, regardless of a high faecal level of gram-negative bacteria. Endotoxin determination by the Limulus amebocyte lysate test appeared to be unaffected by the amount of bacitracin present in faecal preparations after oral administration of this antibiotic. In addition, the in vitro release of endotoxin was not influenced by bacitracin. From these results we conclude, that "free" endotoxin is a product of extensive proliferation of gram-negative bacteria. Therefore, the intestinal endotoxin level does not necessarily correlate with the level of gram-negative bacteria, but corresponds with the proliferative activity of these bacteria.

Animals↗
PubMed1994

Cardioinhibitory peptides from Limulus polyphemus: modulation of the neurogenic heart.

Four neuropeptides have been isolated and sequenced from acetone extracts of brains of the horseshoe crab Limulus polyphemus. They belong to a newly discovered peptide family in invertebrates. A possible role of the four peptides from Limulus as cardioregulatory neurotransmitters has been tested on the isolated Limulus heart. Three of the peptides (DEGHKMLYFamide, GHSLLHFamide, and PDHHMMYFamide) produce dose-dependent decreases in both amplitude and rate of the heart contractions, whereas DHGNMLYFamide reduces only the amplitude of the heartbeat. All four peptides differ in threshold, potency and duration of their effects.

Amino Acid Sequence↗
PubMed1991

Specific assay for endotoxin using immobilized histidine and Limulus amebocyte lysate.

The LAL test is inhibited or enhanced by many substances. To overcome these problems, we have developed a specific endotoxin assay method using an ultrafiltration unit, a fluorometric LAL reagent, and immobilized histidine (which is a specific adsorbent for endotoxins). This method is composed of two steps. The first step is the adsorption of endotoxins. Using immobilized histidine, endotoxins are quantitatively adsorbed on the adsorbent, and the adsorbed endotoxins are separated from LAL-inhibiting or -enhancing substances by the ultrafiltration unit. The second step is the reaction of adsorbed endotoxins with the LAL reagent. The endotoxins adsorbed on immobilized histidine are directly reacted with the LAL reagent in a filter cup and show enough activity for assay. The reproducibility and the accuracy of this method are high, and the recovery of endotoxins from a sample solution is more than 95%. The new endotoxin assay method using immobilized histidine can be utilized for the determination of endotoxins in a solution containing LAL-inhibiting or -enhancing substances such as amino acids and antibiotics instead of requiring employment of the more common gel-clot technique.

Adsorption↗
PubMed1976

Rapid detection of bacterial endotoxins in drinking water and renovated wastewater.

A pilot study was conducted to determine the feasibility of using the Limulus endotoxin assay to detect endotoxins in potable waters and from reclaimed advanced waste treatment (AWT) plant effluents. Water samples were tested using both Limulus lysates prepared in our laboratory and a commercial product, Difco Pyrotest. The Limulus assay procedure was easily adapted to the testing of water samples for endotoxin. Measured endotoxin concentrations varied from 0.78 ng/ml to 1,250 ng/ml. Levels of endotoxin were not predictable based on whether the water was drinking water or AWT water, i.e., some AWT water samples had less endotoxin activity than some samples of drinking water, and some AWT waters had greater endotoxin activity than drinking water. Only three of the water samples tested were free of any detectable endotoxin. Breakpoint chlorination procedures seemed to reduce measurable endotoxin content, whereas passage through activated carbon columns was associated with greater final endotoxin concentrations in test waters.

Biological Assay↗
PubMed1979

The Limulus amebocyte lysate endotoxin assay: current status.

Research conducted during this decade has clearly established the Limulus amebocyte lysate (LAL) test as the most sensitive assay for bacterial endotoxin. In addition, the assay is easily performed, relatively inexpensive, specific for endotoxin, and can be used to test materials that are toxic to rabbits employed in the rabbit pyrogen test. The LAL test has been used in the diagnosis of meningitis, urinary infection, mastitis, and endotoxemia. Other broad applications of the test include quality assurance of parenteral solutions and medical devices as well as the microbial quality of food and water. A review of recent developments in LAL testing is presented and experimental applications of the assay are discussed.

Animals↗
PubMed1995

The diagnostic value of amniotic fluid Gram stain examination and limulus amebocyte lysate assay in patients with preterm birth.

The purpose of this study was to determine the value of Gram stain examination and Limulus amebocyte lysate (LAL) test in the detection of intraamniotic infection. Ninety women with preterm labor and intact membranes (n = 55) or preterm premature rupture of membranes (PROM) (n = 35) who delivered prematurely were included in the study. Amniotic fluid was cultured for aerobic and anaerobic bacteria as well as for mycoplasmas. Amniotic fluid analysis included Gram stain examination and limulus amebocyte lysate tests. The prevalence of positive amniotic culture was 32.2% (29/90) and the most common isolate was Ureaplasma urealyticum. Patients with preterm PROM group had a higher rate of infection than those with preterm labor and intact membranes 57.1% (20/35) vs. 16.4% (9/55), respectively (p = 0.0001). We found a lower gestational age at delivery and lower mean birth weight in neonates born to mothers with a positive amniotic fluid culture than those with negative amniotic fluid culture. The combined use of Gram stain examination and LAL test had a sensitivity and specificity of 51.7% (15/29) and 95.1% (58/61) respectively for the detection of positive amniotic fluid culture. We conclude that Gram stain examination and LAL test are rapid, simple and specific tests that can be used to detect microbial invasion of the amniotic cavity except in patients with mycoplasmas infections.

Adult↗
PubMed1987

The clinical significance of prostaglandins and thromboxane as mediators of septic shock.

An evaluation was made of 106 surgical patients with Gram-negative septic shock, both for clinical criteria as well as the biochemical mediators endotoxin, prostaglandin F2 alpha, prostaglandin I2 (prostacyclin), and thromboxane. These data were correlated to various defined shock phases, functional data of vital organs, and clinical outcome. Patients underwent invasive organ function monitoring and the usual laboratory tests of intensive care. Prostaglandins and thromboxane were measured radioimmunologically, endotoxin by the limulus amebocyte lysate test. Endotoxin proved to be a more accurate predictor of severe sepsis than did positive blood cultures. Endotoxin as well as prostaglandins and thromboxane are predominantly released in early shock phases, appearing in plasma concentrations, which correlate with the severity of organ failure. Sepsis-induced respiratory failure coincides with a deterioration of pulmonary prostaglandin inactivation, which contributes to the release mechanism. High systemic prostacyclin activity benefits the patients' organ functions and clinical outcomes, while a predominance of thromboxane seems to effect the opposite. Transpulmonary-thromboxane gradients correlate significantly with pulmonary hypertension in the early phases of septic shock.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Gram-negative bacteriuria of pregnancy: rapid detection by a chromogenic Limulus amoebocyte lysate assay.

A chromogenic Limulus amoebocyte lysate assay, performed at room temperature, was evaluated for rapid detection (five minutes) of asymptomatic bacteriuria of pregnancy. Development of a distinctive yellow color was used to detect urines containing greater than 10(5) gram-negative bacteria per milliliter. One thousand thirty-nine urine samples were obtained from 664 obstetric patients, with 86 of the specimens shown to contain greater than 10(5) gram-negative urinary tract pathogens. Of these, 74 of 86 were detected by chromogenic Limulus assay; 11 false-positive tests were recorded. At a urine dilution of 1:10, sensitivity and specificity were 88.7 and 98.7%, respectively. Predictive values, based on an attack rate of 10%, were 98.6% for a negative test and 89.9% for a positive test. These data suggest that chromogenic Limulus amoebocyte lysate assay of urine has potential usefulness as a rapid, reliable, and easily performed and interpreted screening test for asymptomatic bacteriuria of pregnancy.

Bacteriuria↗
PubMed1989

Endotoxic activity and enterotoxigenicity of human strains of Campylobacter jejuni isolated from patients in a Nigerian hospital.

Limulus gelation assay and dermal Schwartzman reaction provided a sensitive and reproducible means of testing the endotoxic activity of hospital strains of Campylobacter jejuni in Lagos, Nigeria. All the 22 isolates of Campylobacter jejuni tested for the limulus gelation assay were positive for the production of endotoxin. Furthermore, the Campylobacter suspensions caused a positive dermal Schwartzman reaction in rabbits. The area of skin reaction was less extensive than that produced by Escherichia coli 01114B and E7539/77 which served as positive controls. Five local strains of Campylobacter jejuni tested for enterotoxin production showed negative reaction in the infant mouse test whereas enterotoxin production was observed in Campylobacter jejuni strain 11168 and Escherichia coli E7539/77. Consequently, the infant mouse test may not be suitable for enterogenicity testing of our local isolates of Campylobacter jejuni.

Campylobacter Infections↗
PubMed2004

TNF alpha measurement in rat and human whole blood as an in vitro method to assay pyrogens and its inhibition by dexamethasone and erythromycin.

To ensure the safety of potential drugs, pyrogen tests are traditionally performed in rabbits. New methods have been developed as alternatives to the test to reduce the use of experimental animals. Among these methods there are the Limulus amoebocyte lysate test and the determination of cytokine production by human leukocytes and whole blood. When exposed to a range of concentrations of endotoxins, human and rat whole blood release TNFalpha at amounts that are detectable by a commercially available enzyme-linked immunosorbent assay (ELISA). Our results show that the sensitivity of human and rat blood to endotoxins from Salmonella abortus equi and Escherichia coli is similar. In rat blood, TNFalpha was detected after contact with the pyrogens only in fresh blood, collected on the same day of incubation with the pyrogenic substances. The measurement of TNFalpha production would be a reliable alternative to the rabbit pyrogen test. However, given that the addition of erythromycin and dexamethasone inhibited the production of this cytokine, this method is limited when parenteral formulations contain these two drugs. Similar inhibition has been observed in the rabbit test. Additional experiments will be necessary to demonstrate that the rat whole blood test system is useful and reliable for the pyrogens evaluation.

Animals↗
PubMed1979

Application of LAL for detection of endotoxin in antibiotic preparations.

The Limulus amebocyte lysate (LAL) test has been investigated as an alternative method to the USP pyrogen test for the detection of endotoxin contamination in these antibiotic preparations: clindamycin phosphate, lincomycin hydrochloride, neomycin sulfate, and spectinomycin hydrochloride. The antibiotic preparations were tested at the maximum concentrations that would not inhibit gelation of LAL. The USP pyrogen test was also performed for comparison. The LAL and the USP pyrogen tests correlated extremely well when an acceptance criterion based on the minimum pyrogenic dose (MPD) of endotoxin per human dose of drug was used for the LAL test. Use of this MPD provides a practical and feasible acceptance creiterion for the LAL test and assures that the LAL sensitivity approximates or surpasses that of the USP pyrogen test.

Animals↗
PubMed1988

[Endotoxinemia and bacteremia in manual oral decompression of ileus].

In the framework of the present clinical prospective study using a randomly selected patient collective, the question was pursued whether manual oral decompression (MOD), done in connection with surgical intervention in severely ill patients with ileus of the large and small intestine, leads to detectable bacteremia or higher concentrations of endotoxin in serum. From October, 1985 to March, 1987, bacteriological tests were conducted and the endotoxin concentrations in serum were measured in a total of 31 patients. 71% of the patients were female and 29% were male, aged 18-89. The endotoxin measurement was conducted with the aid of the limulus-amoebocyte-lysate (LAL) test, modified according to Piotrowicz. Additionally, bacteriological tests were done of the operation sites and the decompressed gastro-intestinal secretions. Simultaneously, cultures from the central blood stream were prepared. The tests showed that bacteremia and endotoxinemia occur in connection with manual oral decompression (MOD). Neither of the two, however, has any clinically relevant influence on the further post-operative course. Thus, manual oral decompression continues to represent an indispensable maneuver in the surgical management of an ileus.

Adolescent↗