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At least 415 records · Page 23Linked to original sources
PubMed1976

Hemolytic-uremic syndrome: absence of circulating endotoxin.

In children with hemolytic-uremic syndrome endotoxin determinations were carried out in the peripheral circulation in order to get evidence for the hypothetical role of endotoxin in the pathogenesis of the disease. For this purpose the Limulus test was used to determine endotoxin activity in 16 patients with hemolytic-uremic syndrome. In the plasma of these patients no endotoxin could be detected above the lower detection limit of 100 pg/ml, although in all patients with septicemia due to gram-negative bacilli the test was positive.

Animals↗
PubMed1990

Comparison of the limulus amebocyte lysate test and gas chromatography-mass spectrometry for measuring lipopolysaccharides (endotoxins) in airborne dust from poultry-processing industries.

The lipopolysaccharide (endotoxin) content in airborne dust samples from three different poultry slaughterhouses was determined with both the chromogenic Limulus amebocyte lysate assay and gas chromatography-mass spectrometry analysis of lipopolysaccharide-derived 3-hydroxy fatty acids. Gram-negative cell walls were also measured by using two-dimensional gas chromatography/electron-capture analysis of diaminopimelic acid originating from the peptidoglycan. The correlation between the results of the Limulus assay and those of gas chromatography-mass spectrometry for determination of the lipopolysaccharide content in the dust samples was poor, whereas a good correlation was obtained between lipopolysaccharide and diaminopimelic acid concentrations with the gas chromatographic methods. The results suggest that it is predominantly cell-wall-dissociated lipopolysaccharides that are measured with the Limulus assay, whereas the gas chromatographic methods allow determination of total concentrations of lipopolysaccharide, including Limulus-inactive lipopolysaccharide, gram-negative cells, and cellular debris.

Air Pollutants, Occupational↗
PubMed2004

Detection of lipopolysaccharide in hemoglobin-vesicles by Limulus amebocyte lysate test with kinetic-turbidimetric gel clotting analysis and pretreatment of surfactant.

A method to quantitatively measure the bacterial endotoxin content (lipopolysaccharide, LPS) in phospholipid vesicles or liposomes is necessary because the conventional Limulus amebocyte lysate (LAL) test does not provide an accurate measurement due to the hydrophobic interaction of LPS and vesicles that shields the activity of LPS to clot the LAL coagulant. This interference was evident from isothermal titration calorimetry results in our study that clearly demonstrated the insertion of the LPS molecule into the phospholipid bilayer membrane. Hemoglobin-vesicles (HbVs; particle diameter = 251 +/- 80 nm; [Hb] = 10 g/dL) are artificial oxygen carriers encapsulating a conc. Hb solution in phospholipid vesicles, and their oxygen transporting ability has been extensively studied. To accurately measure the LPS content in the HbV suspension, we tested the solubilization of HbV with deca(oxyethylene) dodecyl ether (C(12)E(10)), used to release the LPS entrapped in the vesicles, as a pretreatment for the succeeding LAL assay of the kinetic-turbidimetric gel clotting (detecting wavelength, 660 nm). The C(12)E(10) surfactant interferes with the gel clotting in a concentration-dependent manner, and the optimal condition was determined in terms of minimizing the dilution factor and C(12)E(10) concentration. We clarified the condition that allowed the measurement of LPS at >0.1 endotoxin units (EU)/mL in the HbV suspension. Moreover, the utilization of histidine-immobilized agarose gel effectively concentrated the trace amount of LPS from the C(12)E(10)-solubilized HbV solution and washed out C(12)E(10) as an inhibitory element. The LAL assay with the LPS-adsorbed gel resulted in the detection limit of 0.0025 EU/mL. Pretreatment with C(12)E(10) would be applicable not only to HbVs but also to other drug delivery systems using phospholipid vesicles encapsulating or incorporating functional molecules.

Animals↗
PubMed1986

Electrokinetic properties of endotoxins and their significance for the limulus amoebocyte lysate test.

The electrokinetic properties of the endotoxins of Escherichia coli and Serratia marcescens have been examined. Both endotoxins are negatively charged, with the zetapotential being increased by the presence of cations whose relative influence resembles the Schulze-Hardy rule for colloid stability. Fe3+ and Th4+ ions are capable of reversing the negative charge of the endotoxin particles to positive. These cations were found to have a strong inhibitory effect on the activity of endotoxins in the limulus amoebocyte lysate test but the inhibitory effect did not parallel changes in the zetapotential because the effect occurred at concentrations too low to affect this parameter.

Animals↗
PubMed1997

[LAL (Limulus Amoebocyte Lysate) test as applied to the safety evaluation of biological preparations].

In the paper some problems concerning of pyrogen testing were described. The risk of reactions after administration parenteral preparations contaminated pyrogenic substances give the cause for searching sensitive, repeated methods of their designation. The paper is review of the adaptation Limulus Amoebocyte Lysate (LAL) test for the estimation of endotoxin in biological preparations. The paper overview, chemical structure of endotoxin the characteristic of Limulus polyphemus, principle basis of the LAL test and general remarks of application. The LAL test according to the opinion of many authors is more sensitive in comparing with the pyrogen rabbit test.

Biological Assay↗
PubMed1985

Clinical utility of the Limulus amebocyte lysate (LAL) test.

The clinical utility of the limulus amebocyte lysate (LAL) test was assessed with eight different body fluids from 44 different studies. The results show that the LAL test has established clinical utility for the detection of endotoxin in the presence of Gram-negative bacteria with 4 body fluids: cerebrospinal fluid (CSF), urine, cervical and urethral exudates, and ocular exudates. At this time, the data are insufficient to establish clinical utility with 4 body fluids: peripheral blood, portal blood, ascitic fluid, and synovial fluid.

Body Fluids↗
PubMed1990

[Blood endotoxin in acute pancreatitis using limulus amebocyte lysate test (LAL test)].

Forty-five cases of acute pancreatitis observed during the period 1986-88 were included in this study. Four of the 45 patients were operated during the acute phase and of these, two died. The remaining 41 patients were treated with conservative therapy using the application of a nasogastric tube, analgesics, and the endovenous administration of various solutions and antibiotics. The severity of each attack of pancreatitis was assessed according to Ranson and Agarwal's criteria. In severe cases (more than 3 of Ranson's criteria) the presence of endotoxin in the systemic circulation was shown using the "limulus" method, together with contemporary low levels of C3 complement factor. As is evident from the results of the study, the presence of endotoxinemia and the low level of C3 in acute pancreatitis are related to the high percentage of complications.

Acute Disease↗
PubMed1984

Endotoxemia in intensive care patients: a longitudinal study with the limulus amebocyte lysate test.

In patients with severe underlying disease and in polytraumatized patients, clinical signs of septicemia caused by infections with gram-negative bacteria are observed postoperatively with increasing frequency. Using a photometric LAL test, a longitudinal assessment of LAL reactivity on 41 intensive care patients was performed. Postoperatively, all patients developed a septicemia of different severity with body temperatures greater than 38.5 degrees C. Dividing the individual disease course, related to body temperatures, into three phases (A-C) it was found that independent of the severity of septicemia, the majority of patients (38/41) yielded a positive LAL reactivity. In phase B (body temperature greater than 38.5 degrees C) more plasma samples contained LAL-reactive material than in phase A and C (body temperature less than 38.5 degrees C). A decline of fever (phase B to C) correlated significantly (P less than 0.05) with the change from positive to negative LAL reactivity. In patients with high leukocyte counts (15-50 X 10(9)/l) a positive LAL reactivity was found more frequently. The majority of patients (21/27) who survived were transferred with negative LAL reactivity to the general wards. The results suggest that single determinations of LAL reactivity are of limited clinical validity. Using the individual profile of LAL reactivity gained through a longitudinal assessment, data upon the development of the disease course can be obtained.

Adult↗
PubMed1981

Rapid diagnosis of bacterial meningitis.

The diagnostic value of several investigations which may demonstrate bacteria or bacterial products in cerebrospinal fluid (CSF) samples from patients with meningitis are discussed. Estimation of CSF lactate and lactate dehydrogenase levels was found to be of value in the differential diagnosis of viral, bacterial and fungal meningitis and the detection of endotoxin by the Limulus amoebocyte lysate test was shown to be strongly suggestive of Gram-negative meningitis. The demonstration of bacterial capsular polysaccharides in CSF by counterimmuno-electrophoresis, latex agglutination and ELISA was of value in establishing a precise aetiological diagnosis, but the usefulness of these methods was limited by the lack of general availability of specific high-potency antisera which determine the sensitivity of the procedure. These screening tests do not replace standard analysis of CSF but provide useful ancillary evidence of meningitis. Negative results obtained from screening tests should not exclude a diagnosis of bacterial meningitis and a decision to withhold treatment should only be made after all available CSF results are evaluated in conjunction with the clinical features.

Bacterial Infections↗
PubMed1976

Application of the Limulus amoebocyte lysate test to the detection of gram-negative bacterial endotoxins in normal and mastitic milk.

The Limulus in vitro endotoxin assay was evaluated as a possible method for the prompt detection and measurement of endotoxins of Gram-negative bacteria in milk. Quantitative results were obtained following 1 h incubation of Limulus lysate and 10-fold dilutions of milk from normal quarters and from quarters of cows with clinical mastitis. This test was capable of detecting endotoxins associated with acute coliform mastitis. A positive Limulus reaction was recorded at dilutions ranging from 1: 10(4) to 1: 10(9) of milk from quarters affected with clinical mastitis due to coliform bacteria. Milk from normal quarters and from clinical mastitis cases due to Gram-positive bacteria was consistently negative to the test when diluted 1:10(3).

Animals↗
PubMed1977

The limulus amebocyte lysate test micromethod and application in the control of sera and vaccines.

To estimate the amount of endotoxin in sera and vaccines relatively high quantities of limulus lysate are necessary. Because this makes the control rather expensive, a micromethod was developed in which the amount of limulus lysate was reduced fivefold. This method was used to estimate endotoxin in typhoid vaccines. The relation between the reactions in man and the amount of endotoxin in the vaccines was examined. In these experiments it appeared that the limulus amebocyte lysate (LAL) test demonstrates predominantly the endotoxin in solution. The test was also used as a control test for calf sera. The culture quality of these calf sera as estimated by the lymphocyte stimulation test appeared to be influenced by previous bacterial contamination as could be demonstrated with the LAL test.

Animals↗
PubMed1977

Comparison of limulus amebocyte lysates and correlation with the United States Pharmacopeial pyrogen test.

Six limulus amebocyte lysate (LAL) preparations obtained from five different suppliers were evaluated for sensitivity, dependability, cost, convenience of use, and correlation with the United States Pharmacopeial (USP) rabbit pyrogen test method. Endotoxins from various gram-negative microorganisms were used for the evaluation. Major differences among the LAL preparations lie in the area of sensitivity. Differences, up to 100-fold, exist in the sensitivity of the various LAL preparations to the same endotoxin. The LAL tests in general were 3 to 300 times more sensitive than was the USP rabbit pyrogen test method. The LAL and the USP rabbit pyrogen test data correlated well when the endotoxin in a relatively pure and undegraded form was examined. However, large discrepancies in correlation were found when partially degraded endotoxins were compared. One LAL preparation responded to both intact and degraded endotoxin, whereas others responded only to intact endotoxin; the latter closely correlated with the febrile response of the rabbit. Therefore, proper selection of an LAL preparation is important for its application in clinical, pharmaceutical, public health, and environmental areas.

Animals↗
PubMed1997

Validation of the limulus amebocyte lysate (LAL) test for routine PET radiopharmaceuticals.

The kinetic turbidimetric limulus amebocyte lysate test was validated as method for detecting endotoxins in short-lived radiopharmaceutical samples. Using this method, radiopharmaceuticals can be released for administration to humans after the test, without extensive loss of radioactivity. Inhibition or enhancement on the LAL results by the product samples were examined in more detail and eliminated.

Ammonia↗
PubMed1985

Endotoxin in blood products: correlation between the Limulus assay and the rabbit pyrogen test.

The possibility of replacing the rabbit pyrogen test by the Limulus (LAL) test, as a final release test for plasma products, was investigated. The LAL test measured the endotoxin content quantitatively, using a chromogenic substrate. The samples were boiled and centrifuged to remove inhibiting substances, which represent a major problem when testing plasma protein samples. In order to correlate the LAL test to the rabbit test, parallel assays were performed on 85 batches of two different human albumin preparations. For both products, a positive correlation was observed between the two tests. However, the pass/fail limit of the rabbit test was found at different endotoxin levels, corresponding to about 2 and 20 ng/kg, respectively. This discrepancy could be removed by extracting the endotoxin before administration to rabbits. It is concluded that the endotoxin, detected in plasma products by the LAL test, may be present in a non-pyrogenic state.

Animals↗
PubMed1977

Functional renal failure and haemorrhagic gastritis associated with endotoxaemia in cirrhosis.

Forty-three patients with cirrhosis and ascites, 21 with normal renal function, 10 with a progressive functional renal failure (FRF), and 12 with a steady FRF, were investigated for the presence of endotoxaemia by the Limulus lysate test. Endotoxaemia was found in nine patients with FRF and in none of the 21 with normal renal function (P less than 0-01). A positive Limulus test was almost exclusively associated with a progressive FRF (eight of 10 patients) and all but one of them died. Renal function improved as endotoxaemia disappeared in the survivor. Endotoxaemia was also associated with haemorrhage due to acute erosions of the gastric mucosa, being present in six of the seven patients who had this complication. Intravascular coagulation was not found in any patient. The Limulus test was positive in the ascitic fluid in 18 of 21 patients tested, although only two of them had peritonitis. These results suggest that endotoxaemia may play a critical role in the development of progressive renal failure and haemorrhagic gastritis in cirrhosis, and emphasise the potential risk of procedures involving reinfusion of ascitic fluid.

Blood Coagulation Tests↗