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PubMed2002

[Therapeutic effect of high-density lipoprotein of human plasma on rat endotoxemia].

OBJECTIVE: To investigate the therapeutic effect of high-density lipoprotein (HDL) of human plasma on rat endotoxemia. METHODS: Rats were divided into 2 groups randomly, the treated group received bolus intravenous endotoxin (500 EU/kg), then followed by a bolus HDL (75 mg/kg) intravenously as their blood pressure decreased obviously. The control group just received bolus intravenously endotoxin (500 EU/kg) without HDL. Blood pressure, survival time, the concentration of TNF and the levels of endotoxin in plasma were determined using radioimmunoassay and limulus lysate test. RESULTS: The decrease of blood pressure was obviously attenuated (P < 0.01), the survival time was significantly increased (P < 0.01) and the concentration of plasma TNF was decreased (P < 0.05) in the treated group, compared with those in the control group. The levels of endotoxin were of no significant difference between the two groups (P > 0.05). CONCLUSION: HDL of human plasma has obvious therapeutic effect on rat endotoxemia it could enhance the resistance of rats to endotoxemia, and the mechanism therein may be related to the inhibition of the release of TNF.

Animals↗
PubMedDate not supplied

An automated sequential injection analysis system for the determination of trace endotoxin levels in water.

A new automated instrument based on the Limulus amebocyte lysate (LAL)-chromogenic substrate kinetic assay for the determination of bacterial endotoxins is reported. A computer controlled syringe pump-multiport valve combination was used to aspirate the sample and other reagents into a holding coil. The syringe was always filled with air; liquid did not enter the syringe. The valve could address up to four individual radial paths, fully referenced optical fiber LED-based absorbance detectors that were housed collectively in a single, small (20 x 20 x 30 mm) metal block with a heater and temperature sensor, and maintained at 37 degrees C. Assay mixtures containing sample or standards were delivered to the individual detector cells for the simultaneous collection of the time based absorbance data. The automated system determined endotoxins with good accuracy and reproducibility in the range of 0.005-0.5 endotoxin units (EU)/mL (r2 > or = 0.99). Based on three times the standard deviation of the blank and the slope of the calibration curve, the lower limit of detection was < or = 0.003 EU/mL. The variability of the assay method is less than 5% (n = 10). Analysis time required for a 0.005 EU/mL standard was <100 min. Appropriately diluted tap water samples were simultaneously analyzed by the present system and a manually loaded commercial microplate reader based instrument; the data were statistically indistinguishable at the 95% confidence level.

Endotoxins↗
PubMed2003

Endotoxins and medical devices: the significance of dead bacteria.

There has been some recent speculation that endotoxins, the toxic molecules that are present in the cell wall of certain bacteria, could play a role in the development of tissue reactions to medical devices. This article discusses the basis for this speculation.

Biocompatible Materials↗
PubMed1992

[Correlativity of plasma endotoxin, plasma fibronectin and common bile duct pressure in severe acute cholangitis].

On the basis of common bile duct pressure measurement (CBDP) in 18 patients of severe acute cholangitis, plasma endotoxin (ET) was determined by modified synthetic chromogenic limulus amebocyte lysate assay and plasma fibronectin (FN) was detected with Laurell's rocket immunoelectrophoresis. CBDP was 2.23 +/- 0.49 KPa in patient group. There was striking positive correlation between ET and CBDP. Preoperative ET was 202.73 +/- 88.57 ng/L in patient group which was much higher than 15.47 +/- 7.38 ng/L in the control (P less than 0.001). Preoperative FN was 141.77 +/- 82.37 mg/L in the patient group which was lower than 317.21 +/- 12.57 mg/L in the control (p less than 0.001). Statistical differences could be noticed in postoperative ET and FN between the survivor and the dead. The study suggested that plasma ET levels are greatly influenced by pressure gradient of bile duct, dynamic observations of ET and FN levels are helpful to monitor disease course and predict prognosis.

Acute Disease↗
PubMed1992

Purification of Limulus polyphemus proclotting enzyme.

Horseshoe crabs (Limulus polyphemus and Tachypleus tridentatus) possess a proteolytic blood coagulation system within their amebocytes that, after release and endotoxin activation, generates a polymerized insoluble coagulin clot. Clotting enzyme from horseshoe crab amebocyte lysate is the protease that activates the clottable protein (coagulogen) which then forms the coagulin clot. Comparison of the previously published descriptions of this enzyme has revealed significantly discordant biochemical characteristics. We purified a 60-kDa proclotting enzyme from L. polyphemus amebocyte lysate to a single band on polyacrylamide gel electrophoresis. After electrophoresis, evaluation of enzymatic activity of this protein within gels demonstrated that the band of purified protein corresponded to enzymatic activity, as detected by amidolytic activity for chromogenic substrates and by gelation of coagulogen applied to the gel. The enzymatic activity was inhibited by serine protease inhibitors. The purified proclotting enzyme had a molecular weight and amino acid composition different from the previously published characterizations of proclotting enzymes from both L. polyphemus and T. tridentatus.

Amino Acids↗
PubMed1992

[Limulus lysate activity of some organisms resided in oral cavity].

Gram-positive and Gram-negative bacteria resided in oral cavity have been investigated using Limulus Lysate Assay. The study showed that both kinds of organisms have Limulus Lysate Activity (LLA). The data from the present study indicated that various species of Gram-positive and Gram-negative bacteria possess different degrees of LLA. There is no significant difference of LLA between Gram-positive and Gram-negative bacteria.

Gram-Negative Bacteria↗
PubMed2004

Endotoxin content in Haemophilus influenzae type b vaccine.

Haemophilus influenzae type b (Hib) is a major cause of bacterial meningitis among children. Hib conjugate vaccines have effectively prevented Hib infection, and routine immunization with Hib conjugate vaccine has diminished the incidence of the disease in the United States and European countries. Introduction of Hib conjugate vaccines is also required in Japan. However, endotoxin that can carry over from Gram-negative H. influenzae with a purified component may contribute to adverse events following Hib vaccination. In the present study, we examined the endotoxin content in Hib conjugate vaccines. The Hib conjugate vaccine batches, which were produced by a European vaccine manufacturer, were shown to have considerably high endotoxin activity and to vary from 13.9 to 173.7 endotoxin units/dose. These results suggest that it is necessary to monitor the endotoxin content of the vaccine batches to ensure the quality and safety of the vaccines.

Animals↗
PubMed2004

Endotoxin measurement in house dust using the end-point Limulus amoebocyte lysate method.

Endotoxin is a lipopolysaccharide, a part of gram-negative bacteria cell membrane commonly present in general and many occupational environments. This paper describes sample preparation and endotoxin measurement in 16 samples of house dust from urban homes (Zagreb, Croatia) using end-point chromogenic Limulus amoebocyte lysate (LAL) bioassay. House dust was collected on cellulose filters by vacuuming bedroom and living room floors, and was kept frozen until assayed. Samples were extracted from filters with a 0.05% solution of Tween-20 in endotoxin-free water. Serial dilutions of samples were measured in duplicates. The linearity of the standard curve was satisfying (r=0.983), as well as the recovery (92 and 110%) and repeatability (coefficient of variation from 0 to 8.5%). The endotoxin levels found in the house dust samples ranged from 4.8 to 200 EU/mg, with the arithmetic mean of 49.5 EU/mg (standard error of the mean of 12.1 EU/mg), and were in the range of house dust endotoxin values obtained by other authors.

Air Pollution, Indoor↗
PubMed2005

Exposure to bacterial endotoxin during conservative dental treatment.

The aim of the study was to determine bacterial endotoxin concentration in the water flowing from a high-speed handpiece of a dental unit and in the air contained in the bioaerosol formed during dental conservative treatment. The air was collected in the space between the patient and dentist. The study was conducted on 25 operative sites (units) and had two stages: before application of a dental unit waterline (DUWL) disinfectant and after a 2-week application of disinfection procedure. The research showed that the mean concentration of bacterial endotoxin in the water flowing from high-speed handpieces was significantly reduced after the use of a disinfectant. The mean concentration of bacterial endotoxin in the air was similar at both stages - before and after application of waterline decontamination procedure. The study showed that in dental air-water aerosol, water is the main source of bacterial endotoxin contaminating the aerosol during the work with dental handpieces. Application of a user-friendly water disinfectant to significantly decrease endotoxin concentration in the DUWL water and in the aerosol, is one of recommended methods to reduce health risk.

Air Microbiology↗
PubMed1991

[Studies on antiaggregating drugs of horseshoe crab amebocytes].

The effects of drugs on amebocyte spontaneous aggregation and endotoxin induced aggregation were studied. N-Ethylmaleimide, ethylenediamine tetraacetate, propranolol, verapamil and lidocaine but not dibutyryl cyclic AMP could reduce the aggregating rate of amebocytes. The speed of degranulation induced by endotoxin was reduced by N-ethylmaleimide, ethylenediamine tetraacetate, propranolol, verapamil and caffeine. These results suggest that Ca+2 and c-AMP may play an important role in amebocyte spontaneous aggregation and endotoxin induced aggregation. The blocking agent of Ca+2 and c-AMP can also antagonize the aggregation of amebocytes.

Animals↗
PubMed1991

Pathophysiological effects of a limulus amoebocyte-lysate-positive substance during haemodialysis.

The washing solution of a dialyser was collected after recirculation of pyrogen-free water through the blood compartment, and the amount of limulus amoebocyte lysate-(LAL)-positive material was measured. Our study shows that the amount of LAL-positive substance on the cuprophane membrane of DIP-02-02 dialyser (USSR) is 5 times greater than in the case of cuprophane membrane of D2 hollow-fibre dialyser (Fresenius). There appears to be an acute increase (0.1 ng/ml) followed by a decline to normal values of LAL-positive substance concentration in the blood of patients in the first hour of haemodialysis using a DIP-02-02 dialyser. We conjecture that the cause of monocyte activation during haemodialysis is the LAL-positive material of the dialyser membrane, which in turn may induce the activation of lipid peroxidation and the increase of prostaglandin E production. However, it is not possible to exclude the likelihood that the origin of endotoxin-like LAL-positive substances lies in the dialysate.

Adult↗
PubMed1991

The Limulus amoebocyte lysate assay for prediction of chlamydial infection in males with non-gonococcal urethritis: an evaluation.

Chlamydia trachomatis produces small amounts of an endotoxin-like material. The Limulus amoebocyte lysate assay was used to evaluate chlamydial cell cultures and also the exudates from adult male patients with non-gonococcal urethritis, as a possible method to subdivide this condition into chlamydial and nonchlamydial urethritis. In vitro endotoxin assays were conducted in McCoy cell media using the Limulus assay, and endotoxin levels were consistently 10-fold less at 24 h than at 0, 48, 72, and 96 h, which may be accounted for by the unique growth cycle of chlamydia. In 75 males with non-gonococcal urethritis, urethral exudates were collected, serially diluted and assayed for endotoxin content. Of these, 27 (36%) had positive chlamydial cultures and 48 were negative. There was no statistically significant correlation between the level of endotoxin present and a positive or a negative culture for C. trachomatis (P greater than 0.05). Sensitivity and specificity of the assay were only 59% and 56%, respectively, at a 1 in 8 dilution; it was not useful in predicting chlamydial culture results in male patients with non-gonococcal urethritis.

Adult↗
PubMed1991

[The value of serum endotoxin determination after gastrointestinal interventions].

Serumendotoxins were measured in 11 patients after gut surgery and compared with healthy people as a standard. In cases of uncomplicated course 3 to 4-fold raised serumendotoxin levels were observed in a typical two-peak pattern. It was not before the fifth day following operation that serum levels declined constantly. In contrast to these findings, patients suffering from septic complications showed a permanently raised endotoxin level, which correlated well with their clinical course. Therefore single peaks of serumendotoxin measured after operation should not be overvalued. Constantly raised levels following operation, however, may indicate some kind of septic complication.

Aged↗
PubMed1991

Detection of bacterial contamination in bone marrow graft.

A rapid method of determining bacterial contamination was used in a series of fifty-five bone marrow harvests (20 allogeneic and 35 autologous transplantations). The microbiological culture assays executed on bone marrow samples soon after the harvest and before the manipulation, showed a positivity only in the autologous bone marrow group. Another positivity was revealed after the freezing process of bone marrows for autologous transplantation. Two samples in the bone marrow group submitted to purging were positive after treatment and freezing process. In this study, the increase of bacterial contamination frequency seemed to be related to extensive handlings, such as pharmacological in vitro purging and freezing procedures.

Bacteria↗