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PubMed1982

In vitro and in vivo association and subcellular distribution of toxic and experimentally modified endotoxin.

Cell association and organ distribution of toxic and experimentally modified endotoxin were compared in whole animals and hepatoma tissue culture (HTC) cells. For both toxic and poly-l-alpha-ornithine mixed endotoxin in vivo, most of the endotoxin becomes associated with the reticuloendothelial system (RES) rich organs. Organ distribution does not change from 1 to 5 h. Significantly less detoxified endotoxin becomes associated with RES-rich organs. Association and nuclear transfer of toxic endotoxin in HTC cells are gradual and time-dependent processes. Plasma treatment increased association of endotoxin with HTC cells. Poly-l-alpha-ornithine (4 micrograms/mL) also significantly increases HTC cell association of endotoxin, and nuclear transfer of endotoxin was similar in principle to the toxic material. Association of detoxified endotoxin with HTC cells is significantly higher than toxic endotoxin and increases with time. In contrast with toxic and poly-l-alpha-ornithine mixed endotoxin, nuclear association of alkaline-treated detoxified endotoxin did not increase significantly during 5 h incubation. Cumulatively, these observations indicate that while tissue culture cells could provide a more controllable experimental system by which to study the fate and pathogenic mechanism of endotoxin at the cellular and subcellular level, HTC cells under the conditions employed herein do not yield binding data which compare favorably with in vivo results. Caution must be exercised when extrapolating in vitro data to the actual in vivo action of endotoxin.

Animals↗
PubMed1986

Effect of heat on endotoxin in plasma and in pyrogen-free water, as measured in the Limulus amoebocyte lysate assay.

Four modes of heating endotoxin in plasma and two different times of heating endotoxin in pyrogen-free water were compared. There were no significant differences in standard curves after heating endotoxin in plasma at 100 degrees C for 1 and for 10 min. However, the standard curve after heating for 10 min at 75 degrees C had a significantly less steep slope, and after heating for 10 min at 56 degrees C, it was completely flat. Heating of endotoxin in pyrogen-free water for 1 min also resulted in the flattening of the standard curve, which was even more pronounced after 10 min of heating.

Endotoxins↗
PubMed1988

A comparative study of virulent and avirulent strains of Chromobacterium violaceum.

A clinical isolate and a soil isolate of Chromobacterium violaceum were compared to determine differences in virulence-related characteristics. Purified lipopolysaccharide (endotoxin) from the virulent, clinical strain was more reactive than that from the avirulent soil strain as determined by the Limulus amebocyte lysate assay. There were no differences in hemolysin or cyanide production between the two strains. The virulent strain was more resistant to phagocytosis and intracellular killing by human polymorphonucleocytes. The clinical strain showed a superoxide dismutase activity 30% higher and a catalase activity fivefold higher than the activities of the soil-isolated strain. The clinical strain also was capable of producing approximately twice as much hydrogen peroxide during growth as compared with the soil isolate. This study suggests that virulence of C. violaceum may be, at least in part, associated with endotoxin, and some protection of the virulent, clinical strain from phagocytic attack is afforded by elevated levels of superoxide dismutase and catalase.

Animals↗
PubMed2002

A review of drinking-water-associated endotoxin, including potential routes of human exposure.

In the past decade efforts have been made to reduce the formation of harmful disinfection byproducts during the treatment and distribution of drinking water. This has been accomplished in part by the introduction of processes that involve the deliberate encouragement of indigenous biofilm growth in filters. In a controlled environment, such as a filter, these biofilms remove compounds that would otherwise be available as disinfection byproduct precursors or support uncontrolled biological activity in distribution systems. In the absence of exposure to chlorinated water, most biofilm bacteria are gram negative and have an outer layer that contains endotoxin. To date, outbreaks of waterborne endotoxin-related illness attributable to contamination of water used in hemodialysis procedures have been only infrequently documented, and occurrences linked to ingestion or through dermal abrasions could not be located. However, a less obvious conduit, that of inhalation, has been described in association with aerosolized water droplets. This review summarizes documented drinking-water-associated incidents of endotoxin exposure attributable to hemodialysis and inhalation. Typical endotoxin levels in water and conditions under which substantial quantities can enter drinking water distribution systems are identified. It would appear that endotoxin originating in tap water can be inhaled but at present there is insufficient information available to quantify potential health risks.

Animals↗
PubMed1994

Natural surfactant and hyperoxic lung injury in primates. II. Morphometric analyses.

Diffuse lung injury is accompanied by low compliance and hypoxemia with histological evidence of endothelial and alveolar epithelial cell disruption. The histological effects of treatment of an acute diffuse lung injury with a natural surfactant product were evaluated in a primate model because surfactant function and content have been shown to be abnormal in diffuse lung injury in both animals and humans. Ten baboons were ventilated with 100% O2 for 96 h, and 5 were given an aerosol of natural porcine surfactant. Physiological and biochemical measurements of the effects of hyperoxia and surfactant treatment are presented in a companion paper. After O2 exposure, lungs were fixed and processed for quantitative electron microscopy. The responses to O2 included epithelial and endothelial cell injuries, interstitial edema, and inflammation. The hyperoxic animals treated with surfactant were compared with the untreated animals; the treatments altered neutrophil distribution, fibroblast proliferation, and changes in the volumes of type I epithelial cells and endothelial cells. Surfactant-treated animals also had decreased lamellar body volume density in type II epithelial cells and preservation of endothelial cell integrity. These changes suggest complex effects of natural surfactant on the pulmonary response to hyperoxia, including protection against epithelial and endothelial cell destruction as well as significant interstitial inflammation and fibroblast proliferation. We conclude that natural surfactant treatment of hyperoxic lung injury in primates resulted in partial protection of epithelial and endothelial cells but also increased the accumulation of fibroblasts in the lung.

Aerosols↗
PubMed1994

Natural surfactant and hyperoxic lung injury in primates. I. Physiology and biochemistry.

Surfactant dysfunction contributes to the pathophysiology of adult respiratory distress syndrome (ARDS), and we hypothesized that surfactant treatment would improve experimental ARDS produced by continuous exposure to hyperoxia. Twelve healthy male baboons (10-15 kg) were anesthetized, paralyzed, and mechanically ventilated with 2.5 cmH2O positive end-expiratory pressure (PEEP) for 96 h. Baboons were divided into three groups: 1) the O2 group (n = 5) received 100% O2, 2) the surfactant group (n = 5) received 100% O2 and aerosolized porcine surfactant, and 3) a control group (n = 2) was ventilated at fractional concentration of inspired O2 of 0.21 for 96 h to control for effects of anesthesia and mechanical ventilation. Hemodynamic parameters were obtained every 12 h, and ventilation-perfusion (VA/Q) distribution was measured daily by multiple inert gas elimination technique. PEEP was increased once or twice daily to 10 cmH2O for 30 min to study its effects on measurements of VA/Q. At the end of experiments, lungs were obtained for biochemical analysis. Prolonged hyperoxia resulted in progressive worsening in VA/Q, hemodynamic deterioration, severe lung edema, and altered surfactant metabolism. Surfactant administration increased disaturated phosphatidylcholine in lavage fluid but did not improve lung edema or gas exchange. In the surfactant group, however, the addition of 10 cmH2O PEEP resulted in a greater degree of shunt reduction than did 2.5 cmH2O PEEP (47 vs. 31% in the O2 group, P < 0.05). We conclude that aerosolized porcine surfactant did not prevent pulmonary O2 injury in baboons, but it potentiated the shunt-reducing effect of PEEP.

Aerosols↗
PubMed2003

Alterations of systemic endotoxemia over the course of acute edematous pancreatitis. correlation to the advent of an infection?

BACKGROUND/AIMS: To define whether bacterial translocation occurs over the course of acute edematous pancreatitis and to correlate its presence to the advent of an infection since data in humans are lacking. METHODS: Thirty-three patients hospitalized over the period January 2000-January 2001 were subjected to venipuncture at regular time intervals for the collection of blood samples for blood culture and for determination of endotoxins and of C-reactive protein. Endotoxins were measured by the Limulus assay and C-reactive protein by nephelometry. RESULTS: A wide range of concentrations of endotoxins was observed over the first 3 days of the disease. Mean (+/-SE) of endotoxins was 4.01 +/- 1.36 and 2.42 +/- 0.95 EU/ml 3 and 6 h, respectively, after admission of afebrile patients. Respective values 3 and 6 h after admission of febrile patients were 3.03 +/- 1.14 and 5.84 +/- 2.28 EU/ml (normal <0.1 EU/ml); these values gradually decreased after the second day. No correlation was found between endotoxins and C-reactive protein. Endotoxins were increased as a result of the occurrence of an infection on the third day. CONCLUSIONS: A significant level of endotoxemia is observed over the course of acute edematous pancreatitis, which might be correlated to the advent of the systemic inflammatory response.

APACHE↗
PubMed1987

The possible role of Limulus-amebocyte-lysate-reactive material in hemodialysis. First-use syndrome.

Hypersensitivity-like reactions are an infrequent but persistent clinical manifestation of hemodialysis. Although a Limulus-amebocyte-lysate-reactive material (LAL-RM) has been demonstrated in some hemodialyzers, its potential role in causing anaphylactoid reactions has not been addressed heretofore. In this chapter, current knowledge about LAL-RM will be presented and integrated with the major mechanisms generally recognized to induce hypersensitivity-type reactions. These mechanisms include: classical induction of allergy by IgE and classical complement activation by IgG and IgM. Alternative complement activation will be not discussed as it has been extensively reported in the literature of hemodialysis and because LAL-RM has not been shown to activate C3a extensively.

Anaphylaxis↗
PubMed1988

Determination of endotoxin levels and their impact on interleukin-1 generation in continuous ambulatory peritoneal dialysis and hemodialysis.

Endotoxins represent a family of ubiquitous bacterial lipopolysaccharides found in water and raw materials. These substances have the ability to generate interleukin-1 (IL-1) and induce fever, as well as other acute phase phenomena. A study was undertaken to determine levels of background endotoxin in (1) continuous ambulatory peritoneal dialysis solution, (2) spent dialysate subsequent to overnight dwell, (3) hemodialysis solution, and (4) Limulus amebocyte lysate-reactive material (LAL-RM) in hemodialyzers and patient plasma. Levels of endotoxin in all of the above cases were less than thought to be required to induce biological activity, such as pyrogenicity, through IL-1 generation. Although nanogram amounts of LAL-RM are associated with some hollow-fiber membranes as well as the plasma of patients on those membranes, this material per se does not appear to produce IL-1 in vitro.

Endotoxins↗
PubMed1997

Detection of peptidoglycan and endotoxin in dialysate, using silkworm larvae plasma and limulus amebocyte lysate methods.

Silkworm larvae plasma (SLP) reagent is activated by peptidoglycan (PG), a fragment of both the gram-positive and gram-negative bacterial cell wall, as well as beta-glucan (BG), a component of fungi. It is possible to measure contamination of gram-positive bacteria quantitatively by combining the conventional limulus amebocyte lysate (LAL) and PG measurement methods. Therefore, a more highly accurate analysis of dialysate can be made using both SLP and LAL methods to detect endotoxin (ET) and/or PG contamination. We studied the effects of contaminated dialysate on human peripheral blood mononuclear cells (PBMC) by producing various cytokines in vitro. Muramyl dipeptide (MDP) was used as the biologically active minimum constituent of PG. A total of 54 dialysate samples were obtained under sterile conditions from 4 sites: (1) reverse osmosis water unit; (2) proportioning unit; (3) multiple dialysate preparation console, and (4) personal dialysate preparation console, at 9 dialysis facilities. To detect bacterial contamination, the samples were measured with LAL(C), LAL(G) and SLP methods. PBMC were collected from 10 healthy controls and from 10 hemodialysis patients and cultured for 24 h with ET, MDP, ET + MDP and contaminated dialysate. IL-1 receptor antagonist (IL-1Ra), IL-1 beta and TNF-alpha in the culture medium supernatants were measured using the ELISA method. PG was not detected in dialysate from sites 1 or 2. However, dialysate from the inlet of the dialyzer at the bedside monitor of the central supply and personal console showed 4.1 +/- 6.1 ng/ml for site 3 (in 7 of 18 samples) and 3.3 +/- 4.6 ng/ml for site 4 (in 3 of 18 samples). Contamination by PG alone and complex contamination by PG and ET were also detected. Furthermore, IL-1Ra, IL-1 beta and TNF-alpha production by PBMC increased in accordance with the concentrations of MDP. Cytokine production was enhanced 5-10 times more where MDP and ET coexisted than where either MDP or ET existed alone, showing the synergic effects of MDP and ET. Based on these results, there is a high possibility that PG may also be a pyrogen in the dialysate prior to this study. ET had been considered the only pyrogen in dialysate. Therefore, it is essential to recognize the existence of both ET and PG in investigating dialysate contamination.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1990

Endotoxin-induced auto-immunity in mice. III. Comparison of different endotoxin preparations.

Six different endotoxin preparations derived from Escherichia coli and Salmonella typhimurium subspecies were compared as to their potencies to provoke auto-immune phenomena in mice. The numbers of spleen cells forming antibodies to bromelain-treated isologous erythrocytes or anti-DNA antibodies, the serum levels of these auto-antibodies, and the circulating immune complex titres were determined. As far as comparison on a weight base was concerned, S. typhimurium Re-mutant lipopolysaccharide appeared to be the most active preparation in inducing auto-antibody formation. Upon comparison of amounts with equal activity in the limulus amoebocyte lysate assay, however, S. typhimurium lipid A turned out to be the most potent. The contribution of O-type specific polysaccharides, phosphate groups, and the lipid A moiety to the potencies of the endotoxin preparations is discussed.

Animals↗
PubMed1994

Bird droppings contain endotoxin and (1-->3)-beta-D-glucan.

Samples of bird droppings were collected and the amount of endotoxin and (1-->3)-beta-D-glucan in these was determined using a specific Limulus assay. All samples contained these agents and calculations on airborne levels demonstrated that doses at risk for inflammation and allergic alveolitis were present. Endotoxin and (1-->3)-beta-D-glucan should be considered in investigations on lung disease induced by bird droppings.

Alveolitis, Extrinsic Allergic↗
PubMed1996

Severity of asthma is related to endotoxin in house dust.

In sensitized subjects, exposure to the mite allergen appears to be only one of several factors leading to asthma. We hypothesized that in association with allergen exposure, endotoxin, a proinflammatory agent present in house dust (HD), influences the severity of asthma. Using a cross-sectional study design, we investigated a group of 69 consecutive dust mite (HDM)-sensitized subjects defined as having rhinitis (n = 20) or asthma (n = 49); the latter were evaluated functionally and clinically by three different scores and by their need for daily medication. Concentrations of Dermatophagoides pteronyssinus p I allergen (Der p I) (by two-site monoclonal antibody enzyme-linked immunosorbent assay [ELISA]), guanine (by high-pressure liquid chromatography [HPLC]), and endotoxin (by modified Limulus. amebocyte lysate assay) were measured in HD collected in duplicate from the mattresses and floors in each subject's home. The concentrations of Der p I and of guanine in HD collected from mattresses were significantly higher in asthmatic subjects than in those with rhinitis (p < 0.05 and < 0.04, respectively). In subjects (n = 37) exposed to a high level of HDM allergen (i.e., Der p I > or = 10 micrograms/g HD and/or guanine > or = 0.10 mg/100 mg HD), the severity of asthma was unrelated to mite allergen concentration in HD. On the contrary, the severity of asthma was related to concomitant exposure to endotoxin in HD, since the concentration of HD endotoxin was significantly and inversely correlated with FEV1 (p < 0.05), FEV1/FVC (p < 0.02), daily need for oral (p < 0.01) and inhaled (p < 0.01) corticosteroids, daily need for beta 2 agonists (p < 0.001) and xanthines (p < 0.01), and clinical scores such as the modified Aas score (p < 0.01). In HDM-sensitized subjects exposed to a high level of allergen, the concentration of endotoxin measured in HD is an important determinant of asthma severity.

Adult↗
PubMed1990

Studies of an antiendotoxin antibody in preventing the physiologic changes of endotoxemia in awake sheep.

In sheep, endotoxin (LPS) causes pulmonary hypertension, hypoxemia, leukopenia, exudation of protein-rich lung lymph, reduced dynamic compliance (Cdyn), and increased resistance to airflow (RL), changes similar to those seen in human sepsis and sepsis-induced ARDS. We used well-described methods in the awake sheep-endotoxin model to evaluate the effectiveness of a commercially manufactured antibody to prevent the physiologic changes of endotoxemia. In awake sheep with chronic lung lymph fistulas, we used a whole-body plethysmograph to measure Cdyn, RL, and FRC. Pulmonary artery, left atrial, and systemic arterial pressures were recorded continuously. Arterial blood gases (for calculating AaPO2), leukocyte counts, and lymph samples were collected every 30 min. Animals received a 30-min (2 mg/kg) infusion of antiendotoxin antibody 4 h before LPS (0.75 micrograms/kg) challenge (n = 4), or were given a mixture of LPS (0.75 micrograms/kg) and antibody (2 mg/kg) that had been incubated in vitro at 37 degrees C for 30 min before infusion (n = 6). A control group given only 2 mg/kg of antibody (n = 4) showed no change in any measured parameter, whereas control animals receiving LPS alone (n = 6) exhibited a typical endotoxin response. In all animals receiving endotoxin, Cdyn declined by approximately 50% within 30 to 60 min, and RL increased approximately sixfold over a similar time course. Accompanying the abnormalities in lung mechanics were pulmonary hypertension, leukopenia, and widening of the AaPO2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Release of tumor necrosis factor after pulmonary artery occlusion and reperfusion.

Cytokines may function as mediators of reperfusion tissue injury in lungs. Because the lung contains resident macrophages that can serve as potential sources of cytokines, we examined the possibility that pulmonary artery occlusion by reperfusion is a factor in mediating the release of cytokines. After left lung ischemia induced by a 24-h period of left pulmonary artery occlusion, we observed a transient increase in TNF-alpha concentration in lung effluent in rabbits during the period reperfusion. The peak TNF-alpha levels ranged from 55 to 335 pg/ml, and a mean peak time was at 45 to 60 min after the initiation of reperfusion. The TNF-alpha concentrations then decreased towards baseline. TNF-alpha was detected in control plasma or in plasma from sham-operated animals. Less than 10 pg/ml of endotoxin was detected in any samples. Lung tissue myeloperoxidase content, a measure of neutrophil infiltration, increased progressively during the 2-h reperfusion period. The time course of generation of TNF-alpha preceded the maximal rise in lung tissue myeloperoxidase activity. The data show that lung ischemia/reperfusion results in transient generation of TNF-alpha, which is known to mediate neutrophil sequestration. Neutrophil sequestration and resulting lung injury after reperfusion may be dependent on generation of TNF-alpha at the onset of reperfusion.

Animals↗