Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ENDOTOXINS”

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 847 records · Page 47Linked to original sources
PubMed2000

Splanchnic endotoxin levels in cirrhotic rats induced by carbon tetrachloride.

BACKGROUND: Bacterial translocation (passage of intestinal bacteria to mesenteric lymph nodes) observed in cirrhosis may be a source of endotoxin that can stimulate nitric oxide production and participate in the pathogenesis of hyperdynamic circulation. Currently, there are no published data concerning splanchnic endotoxin levels in cirrhotic rats. This study was designed to determine systemic and portal hemodynamics and to detect endotoxins in the portal and systemic circulation. METHODS: Liver cirrhosis was induced by carbon tetrachloride intragastric gavage. Systemic and splanchnic endotoxin levels in control rats and cirrhotic rats with or without ascites were measured using a chromogenic Limulus assay. In addition, systemic and portal hemodynamic data were obtained using a thermodilution technique and catheterization. RESULTS: Cirrhotic rats with ascites had the lowest systemic vascular resistance (2.6 +/- 0.1 mmHg.ml-1.min.100 g body weight, BW) compared with control rats (6.3 +/- 0.3 mmHg.ml-1.min.100 g BW; p < 0.05) and cirrhotic rats without ascites (3.7 +/- 0.3 mmHg.ml-1.min.100 g BW; p < 0.05). Cirrhotic rats with ascites displayed the highest splanchnic levels of endotoxin (10.6 +/- 3.1 pg/ml) compared with cirrhotic rats without ascites (2.0 +/- 0.7 pg/ml; p < 0.05) and control rats (2.0 +/- 0.4 pg/ml; p < 0.05). There was no difference in the splanchnic endotoxin levels between control rats and cirrhotic rats without ascites (p > 0.05). Similar results were observed with systemic endotoxin values (cirrhotic rats with ascites, 10.8 +/- 2.8 pg/ml; cirrhotic rats without ascites, 2.7 +/- 0.6 pg/ml; control rats, 2.5 +/- 0.4 pg/ml; p < 0.05). A significant correlation existed between portal and systemic endotoxin values in cirrhotic rats with or without ascites (r = 0.96, p < 0.001 and r = 0.9, p < 0.05, respectively), whereas this correlation did not exist in control rats (r = 0.5, p > 0.05). CONCLUSIONS: Cirrhotic rats with ascites had the lowest systemic vascular resistance and the highest splanchnic endotoxin levels when compared with cirrhotic rats without ascites and control rats. These results suggest that splanchnic endotoxemia may be involved in the development and/or maintenance of hyperdynamic circulation.

Animals↗
PubMed2000

The effect of the glucocorticoid Oradexon on endotoxin-induced peritoneal cell response.

Glucocorticoids are important modulators of immune reactions. They are capable of antagonising several effects of the bacterial endotoxin by inhibiting endotoxin-induced leukocyte activation, and the production of cytokines and inflammatory mediators. We earlier demonstrated that the antiglucocorticoid RU 38486 enhances the cytokine production induced by endotoxin and aggravates the course of experimental endotoxic and septic shock. In the present study we investigated the effect of the glucocorticoid Oradexon on the endotoxin-induced peritoneal cell response. For measurement of the peritoneal cell response, male CFLP mice (20-25 g) were injected i.p. with 10 microg/10 g body weight endotoxin (E. coli 026:B6 LPS, Difco Lab, Detroit, lot 110273JB). Dexamethasone (Oradexon, N.V, Organon Oss, The Netherlands) was administered i.p., i.v. or s.c. in a dose of 0.1 mg/10 g body weight, alone or concomitantly with endotoxin. We found that bacterial endotoxin increased the total cell count due to neutrophilia at 24 hours and, due to increases in the number of macrophages and lymphocytes 48 and 72 hours after treatment, respectively. The i.p., i.v., and s.c. injection of Oradexon, increased the total cell count and the macrophage count at 24, 48 and 72 hours. The i.p., s.c. and i.v. injection of Oradexon, concomitantly with endotoxin, reduced the total cell count at 48 and 72 hours, due to decreases in the macrophage count. The i.p., i.v. or s.c. administration of Oradexon concomitantly with LPS decreased the lymphocyte count and the neutrophil count at 24 and 72 hours. These results prove that glucocorticoids are capable of modifying the immune cell reactions induced by endotoxin.

Animals↗
PubMed2002

Evaluation of airborne dust and endotoxin in corn storage and processing facilities in Colorado.

The main objectives of this research were to determine what aerosols were present by taking total dust (TD) samples and thoracic particulate mass samples (TPM) on farms and in grain elevators. Cascade impactors were used to characterize size distributions of dust and endotoxins at each site. Total dust concentrations on farms had a geometric mean 3.4 mg/m3 and 3.3 mg/m3 in elevators. The geometric mean (GM) concentrations for the TPM were 2.4 mg/m3 on farms and 1.0 mg/m3 in elevators. Endotoxin concentrations as geometric means were alarming at 3175 EU/m3 total dust and 983 EU/m3 by TPM on farms. In elevators, the GM concentrations for endotoxins were 2534 EU/m3 total dust, and 526 EU/m3 by TPM. The mass median aerodynamic diameter (MMAD) for endotoxins on farms was 8.0 microm and 6.5 microm in elevators. The paired t-test was applied to the log ratios of endotoxin concentrations (EU/m3) and dust concentrations (mg/m3), for paired samples of the TD and TPM. A higher content of endotoxins was associated with TPM for farms but not elevators. It was concluded that although the TPM fraction (dust) may represent a small part of the total mass, the aerosol size is optimum for deposition in the lung's tubular airways, and might cause airway inflammation due to the endotoxins. The TPM fraction of corn dust represents the best measure of exposure with regard to the potential development of long-term airways inflammation, and the potential of chronic obstructive pulmonary disease among chronically exposed workers. All endotoxin concentrations were well above recommended exposure levels of several researchers familiar with endotoxin health effects.

Aerosols↗
PubMedDate not supplied

Effects of intra-amniotic endotoxin on lung structure and function two months after term birth in sheep.

OBJECTIVE: Intra-amniotic endotoxin causes chorioamnionitis and results in improved lung function after preterm delivery in sheep. Our aim was to determine the effects on lung structure and function after term birth in lambs exposed to intra-amniotic or intra-allantoic endotoxin. METHODS: At 119 days' gestation, pregnant ewes bearing singleton fetuses received intra-amniotic or intra-allantoic injections of either saline (allantoic, n = 1; amniotic, n = 10) or Escherichia coli (055:B5) endotoxin (allantoic, n = 5; amniotic, n = 7). Amniotic or allantoic fluid was aspirated for white blood cell counts 24 hours after the injections. Ewes (n = 20) were allowed to deliver spontaneously. At 8 weeks' postnatal age we measured ventilation, lung volumes, and compliance in the offspring and collected their lungs for morphologic analysis. RESULTS: Higher amniotic or allantoic cell counts were confined to the fluid space into which endotoxin was injected. Saline injections did not increase amniotic or allantoic white blood cell counts. Gestation length, birth weight, and postnatal growth were unaffected by endotoxin treatments. Lung volumes and compliances at 8 weeks of age were not different between saline-treated and endotoxin-treated groups. Lung morphometry was not significantly altered by endotoxin, with one minor exception: interlobular septal volume was increased by intra-amniotic endotoxin, but this effect had no functional consequences. CONCLUSIONS: Intra-amniotic or intra-allantoic endotoxin caused a localized inflammatory response but did not cause preterm delivery or intrauterine growth restriction. The functional improvements and corresponding structural alterations in the lungs of preterm lambs, reported previously in this model, were not associated with improved or impaired lung function or marked alterations in lung structure 2 months after birth at term.

Aging↗
PubMedDate not supplied

Estimation of endotoxin in infected bile from patients with biliary diseases.

Diseases of the biliary tract can get complicated by infection. Endotoxin may theoretically be responsible for damage to the gall bladder due to its numerous pathophysiological effects. The aim of the present study was to detect and semi-quantitate the amount of endotoxin present in the bacteriologically positive bile samples and to correlate the endotoxin levels with the clinical profile of the patients. One hundred patients with gall bladder diseases and with infected bile constituted the population for investigation. The clinical profile included presence of fever, jaundice, abdominal pain and gall bladder stones. Endotoxin detection and semi-quantitation in the bile samples were carried out using the Limulus amoebocyte assay: Of 100 infected bile samples investigated, 9 samples (9%) were positive for endotoxin ranging from 1.9 EU/ml to 15 EU/ml. Four of them had Klebsiella pneumoniae, 2 had Acinetobacter anitratus and one each of the remaining 3 samples was positive for (i) Escherichia coli and Serratia marcescens (ii) Pseudomonas aeruginosa and (iii) Salmonella enteritidis. The stool sample of the patient with S. enteritidis in the bile also grew the same microorganism. Statistical analysis showed a significant increase in the presence ofjaundice (p<0.05) and abdominal pain (p<0.01) in the endotoxin positive patients compared to the endotoxin negative ones. Hitherto this is the first report that investigated the endotoxin levels in the bile of patients with gall bladder and biliary tract diseases, along with their biliary bacterial profile. Further research is warranted on the effects of endotoxin on gall stone formation.

Adolescent↗
PubMed1990

Endotoxin removal by anion-exchange polymeric matrix.

The effects of anion-exchange polymeric matrices on endotoxin removal from albumin and gamma-globulin solutions are evaluated. The positively charged cellulose acrylic media carrying DEAE or QAE functional groups remove significant amounts of endotoxin from tap water, but are less effective in protein solutions. With properly controlled pH levels and salt concentrations, the endotoxin level in a protein solution can be reduced; however, low endotoxin concentrations, less than 100 pg/ml, are more difficult to remove. The endotoxin removal capacity depends on the number of functional groups existing in the matrix, expressed as the number of milliequivalents (meq), and on the pH operable range, which is directly related to the pK alpha value of the matrix. The effects of pH and salt on endotoxin removal from albumin and gamma-globulin solutions by an anion-exchange polymeric matrix were evaluated statically in test tubes. In addition, a dynamic flow was performed under statically defined conditions on a 250-ml DEAE cartridge for the removal of endotoxin from albumin at a flow rate of 40 ml/min. A greater than 75% reduction in the endotoxin can be achieved, with protein loss occurring only in the early stage of removal. Such processes are useful for the reduction of endotoxin from biological solutions produced by natural sources or recombinant DNA technology.

Adsorption↗
PubMed1990

Contribution of platelet activating factor to hemodynamic and sympathetic responses to bacterial endotoxin in conscious rats.

The effect of the platelet activating factor (PAF) antagonist WEB 2086 on blood pressure; heart rate; and plasma glucose, lactate, and catecholamine concentrations were examined following either PAF or endotoxin administration in conscious rats. PAF infusion (50 ng/kg/min for 60 min) resulted in a sustained hypotension, with tachycardia and elevated plasma norepinephrine (NE; 1.8-fold increase), epinephrine (E; 6.7-fold increase), and dopamine (DA; 1.0-fold increase) at 30 min after beginning infusion. Plasma NE, E, and DA became 4.1 (NE)-, 17.4 (E)-, and 3.3 (DA)-fold higher than control at 60 min after beginning infusion. Both the hemodynamic and plasma catecholamine alterations induced with PAF were completely blocked with WEB 2086 pretreatment. Bacterial endotoxin treatment (5 mg/kg, i.v. bolus) produced well-characterized responses of hypotension, tachycardia, hyperglycemia, hyperlactacidemia, and an elevation in plasma catecholamines. Whereas complete blockade of the hypotensive and tachycardic effect of endotoxin was achieved with WEB 2086 at 30 min following endotoxin, the increases in plasma catecholamines and lactate elicited by endotoxin were attenuated but remained significantly higher than control levels. Hyperglycemia following endotoxin was not altered by WEB 2086 treatment. In endotoxic rats pretreated with WEB 2086 there was significant hypotension, tachycardia, and hyperlactacidemia and an elevation in plasma catecholamines at both 60 and 120 min, but all were less severe compared to non-WEB 2086-treated endotoxic animals. The results demonstrate that WEB 2086 completely blocked early endotoxin-induced hypotension and tachycardia but not catecholamine elevation following endotoxin. This work suggests that sympathetic activation following endotoxin may be mediated by factors other than hypotension.

Animals↗
PubMed1990

Some effects of gram-negative bacterial endotoxin and its importance as a contaminator of biological preparations.

The purpose of this study was to establish a model which can be used to examine the biological response to Salmonella typhimurium endotoxin in both anaesthetized and unanaesthetized rabbits, and then compare this response to that of rabbits injected with an endotoxin-contaminated biological preparation. The parameters used to evaluate the biological response included total white blood cell and differential counts, 15-ketodihydro-PGF2 alpha concentration, and rectal temperature. Unanaesthetized groups of rabbits received 1000, 100, 10, or 1 ng/kg of the endotoxin via intravenous injection (i.v.); the anaesthetized group of rabbits received 100 ng/kg endotoxin i.v. (anaesthesia induced with Hypnorm). In addition, groups of rabbits were treated under anaesthesia with Pharmacia-Chiron's recombinant human Cu/Zn superoxide dismutase (SOD) (10 mg/kg body weight = 1.6 endotoxin units (EU)/kg) or Grünenthal's bovine SOD (two doses: 10 mg/kg = 400 EU/kg, or 50 mg/kg = 2000 EU/kg). Results demonstrated that at the lower doses of endotoxin (10 and 1 ng/kg) and r-hSOD (10 mg/kg), no leukopenia was observed. There was however a slight shift in the leukocyte population so that polymorphonucleocytes increased and monocytes decreased in number. Rabbits treated with higher doses of endotoxin (1000 and 100 ng/kg) showed many of the common signs of endotoxemia, including leukopenia, increased prostaglandin metabolite levels, and increased body temperature, as did the rabbits treated with endotoxin-contaminated bSOD. There was a definite dose-dependency, with the higher dose of bSOD giving a more marked rise in all parameters. These findings indicate that use of this or other endotoxin-contaminated biological preparations in live-animal experiments could produce erratic, and therefore unreliable, results.

Animals↗
PubMed1990

Comparative hemodynamics and cardiovascular effects of endotoxin and platelet-activating factor in rat.

We have compared the cardiovascular effect of endotoxin with platelet-activating factor (PAF) in rats. Endotoxin injected into perfusate of isolated rat heart did not induce significant changes in heart function, whereas PAF induced elevation of coronary perfusion pressure (CPP), decrease in ventricular pressure (VP), decrease in coronary flow (CF), but no significant changes in heart rate (HR). Neither endotoxin nor PAF caused contraction or relaxation of isolated rat arteries. However, endotoxin in the presence of macrophages caused contractions of rat aortic strips. These contractions were potentiated when platelets were present in the macrophage preparation. PAF in the presence of platelets caused profound contraction of the aortic strips, and this action of PAF was entirely blocked by either PAF antagonists or thromboxane antagonists. Injection of endotoxin into rats (i.v.) caused a decrease in blood pressure (BP) without significantly affecting the HR. At higher concentrations (greater than or equal to 10 mg/kg), endotoxin caused ventricular tachycardia (VT) associated with ventricular fibrillation (VF). PAF in vivo caused a rapid and sustained decrease in BP, with an ED50 of 3 micrograms/kg. PAF antagonists significantly prevented overall mortality induced by PAF and short-term endotoxin-induced mortality, but not the long-term (week) mortality. Endotoxin (10 mg/kg) injected into rats caused the release of PAF into the circulation, reaching a maximum after 2-5 min. Tritiated PAF injected into rats i.v. was metabolized over 60 min into lyso-PAF (approximately 30%), acyl-PAF (approximately 10%), and some degraded products (approximately 10%), and the remainder was found in the form of PAF. The results of the present study suggest that PAF may play a significant role in the pathogenesis of endotoxin shock. The action of PAF requires the participation of cells such as platelets, macrophages, neutrophils, and monocytes and involvement of arachidonic acid metabolites.

Animals↗
PubMed1990

Effect of Pasteurella haemolytica-derived endotoxin on pulmonary structure and function in calves.

The role of endotoxin in the pathogenesis of acute pneumonic pasteurellosis is uncertain. Recently, we reported that Escherichia coli-derived endotoxin given by airway inoculation fails to induce lung injury in calves. Because Pasteurella haemolytica-derived endotoxin may differ substantially from E coli in its pathogenicity, we repeated these studies with Pasteurella endotoxin. Intratracheal inoculation of P haemolytica endotoxin caused hypoxemia and increased the alveolar-arterial oxygen differences without causing hypercarbia or changes in lung mechanical properties and volumes. In contrast, IV inoculation of endotoxin caused systemic hypotension, leukopenia, gas exchange impairment, increased total pulmonary resistance, and decreased dynamic compliance. Both routes of inoculation increased serum endotoxin concentrations and were associated with areas of pulmonary hemorrhage, edema, and acute inflammation. We concluded that P haemolytica-derived endotoxin is pathogenic by IV and airway routes of inoculation, and therefore differs from E coli endotoxin in its ability to induce lung lesions in calves.

Animals↗
PubMed1987

Endotoxin-induced hypotension in rats is not mediated by prekallikrein activation.

To test whether endotoxin decreases blood pressure acutely in rats by activating the plasma kinin-forming system, plasma kallikrein activity was determined in different experimental settings of endotoxemia. Conscious normotensive rats were infused for 45 min with endotoxin (LPS E. coli 0111:B4) at a dose (0.01 mg/min) which had no effect on blood pressure. Additional rats were infused with the vehicle of endotoxin. Plasma prekallikrein activity was measured at the end of the 45 min infusions. In other rats, a bolus intravenous injection of endotoxin (2 mg) was administered following the 45 min infusion of endotoxin or its vehicle. In these two latter groups of rats, plasma prekallikrein activity was determined 15 min after administration of the bolus dose of endotoxin. In rats pretreated with the endotoxin infusion, the bolus dose of endotoxin had no significant effect on blood pressure, whereas rats infused with the vehicle became and remained hypotensive up to the end of the experiment. There was however no significant difference in plasma prekallikrein activity within the different groups of rats. In another group of rats, dextran sulfate (0.25 mg i.v.), which activates factor XII and thereby the conversion of prekallikrein to kallikrein, induced a short-lasting fall in blood pressure. 15 min after administration of dextran sulfate, plasma prekallikrein activity was almost completely suppressed. These results obtained in unanesthetized rats strongly suggest that the blood pressure fall induced by E. coli endotoxin is not due to activation of prekallikrein and consequently of the kinin-forming system.

Animals↗
PubMed1989

A possible mechanism of the inhibitory effect of endotoxin on adenylate cyclase.

The possible mechanism of the inhibitory effect of endotoxin on adenylate cyclase was investigated. Plasma membranes were isolated from porcine thyroid gland and rat liver. The effects of endotoxin on adenylate cyclase activity was determined. The adenylate cyclase activity followed in the presence of various concentrations of guanosine-imidodiphosphate (5 x 10(-8)-10(-6) M) and NaF (0.1-10 mM) was markedly inhibited by endotoxin. Moreover, the basal activity of adenylate cyclase was inhibited similarly. The inhibition was concentration dependent. At 400 micrograms/ml of endotoxin a 60% inhibition of adenylate cyclase both without and in the presence of activators was detected. The inhibitory effects of endotoxin and its radiodetoxified derivative were similar. Neither of the two investigated endotoxin preparations tested had any effect on the 3H-guanosine-imidodiphosphate binding activity of adenylate cyclase (neither on the binding capacity, nor on the Kd value). Forskolin activated adenylate cyclase was also inhibited markedly by both endotoxin and radiodetoxified endotoxin. These results suggest that beyond the other membrane effects there is a probability of direct inhibitory effect of endotoxin on the catalytic subunit of adenylate cyclase.

Adenylyl Cyclase Inhibitors↗
PubMed1987

Beneficial effects of a leukotriene antagonist on endotoxin-induced acute hemodynamic alterations.

The role of lipoxygenase metabolites of arachidonic acid as inflammatory mediators of endotoxin shock remains uncertain. In this study the effect of LY171883, a selective leukotriene D4/E4 antagonist, on the hemodynamic alterations of endotoxin shock was assessed. Adult male rats were given an intraperitoneal injection of LY171883 (30 mg/kg) or vehicle 10 minutes prior to intravenous injection of endotoxin (15 mg/kg) or vehicle. Cardiac output, mean arterial pressure, and multiple organ blood flows were determined at 30 minutes after endotoxin or vehicle administration with 85Sr-radiolabeled microspheres. Cardiac output decreased from 32.1 +/- 2.7 ml/min/100 g in the control group to 16.3 +/- 2.7 ml/min/100 g in endotoxin-treated animals (P less than .05). Pretreatment with LY171883 blunted significantly (P less than .05) this fall in cardiac output (26.3 +/- 2.6 ml/min/100 g). Endotoxin reduced mean arterial pressure from 95 +/- 8 mm Hg in controls to 57 +/- 8 (P less than .05), which was not, however, different from control values in rats receiving the LTD4/E4 antagonist. There was also significant (P less than .05) blunting of the endotoxin-induced fall in blood flow to the heart, gastrointestinal tract, and kidneys in animals pretreated with LY171883. Our data demonstrate that this selective leukotriene D4/E4 antagonist has significant salutary actions in endotoxin shock and suggest that LTD4 and/or E4 mediate, in part, the acute hemodynamic sequelae of endotoxin shock.

Acetophenones↗
PubMed1987

Hepatic serine and alanine metabolism during endotoxin-induced fever in sheep.

Time course changes in plasma amino acid concentrations and the hepatic metabolism of serine and alanine were measured in six mature wethers during endotoxin-induced fever. In separate trials, the animals' responses to injections of saline and endotoxin were measured. The endotoxin was from Escherichia coli serotype 055:B5 and was injected intravenously (4 micrograms/kg body weight). Liver biopsies were obtained from the sheep at 6 h postinjection during both endotoxin and saline injection trials. Rectal temperature in the endotoxin treated animals was increased (P less than 0.05, above that in control animals from 4.25 h to 9 h postinjection, with a maximum rise of 2.43 degrees C at 5.5 h postinjection. Glucose concentration in jugular plasma decreased (P less than 0.05) by 3 h postinjection and remained depressed throughout the 24 h postinjection sampling period. Plasma serine concentration was decreased (P less than 0.05) by 3 h postinjection. Plasma alanine concentration was decreased significantly (P less than 0.05) only at 24 h postinjection. Endotoxin injection increased (P less than 0.05) hepatic oxidation of 14C-serine (162%) and the net incorporation of 14C-serine carbon into hepatic protein (173%) and glycogen (275%). The net incorporation of 14C-alanine carbon into hepatic protein (172%) and glycogen (323%) were increased (P less than 0.05) by endotoxin injection, while alanine oxidation was not affected by endotoxin treatment (P greater than 0.05). The increased hepatic use of serine may explain, in part, the dramatic decrease in plasma concentrations of this amino acid following endotoxin injection into sheep.

Alanine↗
PubMed1988

Microcirculatory disturbances in endotoxin-induced disseminated intravascular coagulation. The effects of heparin and gabexate mesilate on locomotive and metabolic changes of neutrophils.

Neutrophil-mediated oxidative stress on the rat mesenteric microcirculation was studied in the experimental model of endotoxin-induced disseminated intravascular coagulation (DIC) by using an intravital fluorescent technique and luminol-dependent chemiluminescence (ChL) analysis. Leukocytes sticking to the venules were visualized by the injection of acridine orange, a fluorochrome tracer which shows high affinity to white cells. Endotoxin (E coli, O-111B4, Difco, USA) was infused intravenously at a dose of 2 mg/kg/hr. After starting the infusion of endotoxin, the number of sticking cells were gradually increased on the venular endothelium followed by a transient neutropenia. In order to investigate the distribution of infused endotoxin in the microvasculature, FITC-labeled endotoxin (Sigma, USA) was used. After administration of FITC-endotoxin, multiple patches of fluorescence along the venular walls were observed, while no fluorescent conjugates were found at the sticking neutrophils and along the arteriolar walls. ChL activities of neutrophils were also dramatically elevated, which may reflect the enhanced ability to generate oxyradical species. To investigate the inhibitory effects of heparin sodium and gabexate mesilate which was a synthetic protease inhibitor on locomotive and metabolic changes of neutrophils induced by endotoxemia, both agents were administered prior to endotoxin infusion. Gabexate mesilate attenuated these changes, but heparin sodium did not show any improving effects. It was concluded that endotoxin primarily affects the venular endothelial cells, resulting in the activation of neutrophils. Gabexate mesilate was more likely to attenuate neutrophil-mediated oxidative stress on microvasculature in endotoxin-induced DIC than heparin sodium.

Animals↗
PubMed1977

An improved in vitro pyrogen test: to detect picograms of endotoxin contamination in intravenous fluids using limulus amoebocyte lysate.

A method for in vitro pyrogen testing using Limulus amoebocyte lysate (LAL) has been described. The method is based upon the measurement of endotoxin-precipitable protein and can be used to measure picogram quantities equivalent to E. coli endotoxin in unknown solutions. When increasing concentrations of E. coli endotoxin are added to a constant amount of LAL and the reaction is allowed to proceed to completion, there is a proportional increase in the protein precipitated by endotoxin. Therefore, by measuring the amount of protein precipitated from LAL, it is possible to determine the equivalent E. coli endotoxin concentration in unknown solutions, when samples of the unknowns are run simultaneously with E. coli endotoxin standards and negative controls. The endotoxin proportional precipitation of protein occurs in reaction mixture showing gelation as well as in reaction mixture where the levels of endotoxin are lower than required for gelation. Determination of precipitated protein provides greater sensitivity for endotoxin detection than the gelation methods currently in use.

Analysis of Variance↗
PubMed1977

Detection of endotoxins in human blood and plasma. An improved in-vitro pyrogen test.

We describe an improved in-vitro procedure for detection of endotoxin in human blood and plasma by use of Limulus amoebocyte lysate. Increasing concentrations of Escherichia coli endotoxin added to a constant amount of the lysate cause a proportional increase in protein precipitated by the endotoxin. By measuring the amount of protein precipitated, it was possible to determine the equivalent E. coli endotoxin concentration in unknown samples, when samples were run with E. coli endotoxin standards and negative controls. The E. coli endotoxin, present in human whole blood and platelet-rich plasma, failed to react with the lysate. However, the concentration of endotoxin in whole blood and platelet-rich plasma could be measured with this Limulus test after lysing the platelets to release the endotoxin and subsequently removing the inhibitory proteins by chloroform precipitation. With this procedure it was possible accurately and repeatedly to determine E. coli equivalent endotoxin concentrations as low as 195 ng per liter of whole blood or 49 ng per liter of platelet-rich plasma.

Analysis of Variance↗
PubMed1986

Direct effects of E coli endotoxin on structure and permeability of pulmonary endothelial monolayers and the endothelial layer of intimal explants.

The direct structural, metabolic, and physiologic effects of Escherichia coli endotoxin on bovine pulmonary endothelial monolayers and on the intact endothelial layer of bovine pulmonary artery intimal explants were examined. Endothelial monolayers exposed to E coli endotoxin (0.001, 0.01, 0.1, 1.0, and 10 micrograms/ml) for 24 hours in the absence of bovine fetal calf serum (FCS) showed a dose-dependent response, as demonstrated by number of pyknotic cells and lactate dehydrogenase release that was enhanced by addition of FCS. Prostacyclin production was increased only in the presence of FCS. Endotoxin also caused an increase in permeability. Endothelial cells on nitrocellulose filters placed in chemotaxis chambers with radioactive tracers in the upper well showed a significant 25% increase in rate of equilibration (counts in lower well/counts in upper well) of 3H-water after 2 and 3 hours' incubation with endotoxin (3 hours' endotoxin = 0.89 +/- 0.03 m +/- SE; no endotoxin = 0.69 +/- 0.05) and a 40% increase in equilibration of 125I-albumin at three hours (3 hours' endotoxin = 0.40 +/- 0.03; no endotoxin = 0.27 +/- 0.02). An increase in hydraulic conductance was also seen at 1 hour. Electron microscopy of the endothelial layer of intimal explants showed dilatations in the intercellular junctions and cellular changes representing contraction--increased prominence of cytoplasmic filaments, nuclear crenation, and cytoplasmic protrusions--at 30 and 60 minutes. From 2 hours evidence of cell death was found. Thus, endotoxin causes structural and metabolic changes in pulmonary endothelial cells and an increase in permeability of the endothelial layer. The injury occurs in the absence of FCS but is enhanced by its addition.

Animals↗