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At least 1,027 records · Page 57Linked to original sources
PubMed2003

Cathelicidin peptide sheep myeloid antimicrobial peptide-29 prevents endotoxin-induced mortality in rat models of septic shock.

The present study was designed to investigate the antiendotoxin activity and therapeutic efficacy of sheep myeloid antimicrobial peptide (SMAP)-29, a cathelicidin-derived peptide. The in vitro ability of SMAP-29 to bind LPS from Escherichia coli 0111:B4 was determined using a sensitive limulus chromogenic assay. Two rat models of septic shock were performed: (1) rats were injected intraperitoneally with 1 mg E. coli 0111:B4 LPS and (2) intraabdominal sepsis was induced via cecal ligation and single puncture. All animals were randomized to receive parenterally isotonic sodium chloride solution, 1 mg/kg SMAP-29, 1 mg/kg polymyxin B or 20 mg/kg imipenem. The main outcome measures were: abdominal exudate and plasma bacterial growth, plasma endotoxin and tumor necrosis factor-alpha concentrations, and lethality. The in vitro study showed that SMAP-29 completely inhibited the LPS procoagulant activity at approximately 10 microM peptide concentration. The in vivo experiments showed that all compounds reduced the lethality when compared with control animals. SMAP-29 achieved a substantial decrease in endotoxin and tumor necrosis factor-alpha plasma concentrations when compared with imipenem and saline treatment and exhibited a slightly lower antimicrobial activity than imipenem. No statistically significant differences were noted between SMAP-29 and polymyxin B. SMAP-29, because of its double antiendotoxin and antimicrobial activities, could be an interesting compound for septic shock treatment.

Animals↗
PubMed1992

Meningococcal endotoxin in lethal septic shock plasma studied by gas chromatography, mass-spectrometry, ultracentrifugation, and electron microscopy.

We have compared gas chromatography and mass spectrometry (GC-MS) analysis with the Limulus amebocyte lysate (LAL) assay to quantify native meningococcal lipopolysaccharides (LPS) in five patient plasmas containing greater than 5 micrograms/liter by LAL. 3-Hydroxy lauric acid (3-OH-12:0) was used as a specific lipid A marker of neisserial LPS. The quantitative LAL results were confirmed by GC-MS (r = 0.98, P = 0.006). Seven patient plasmas were centrifuged at 103,000 g and the sedimentation behavior of native LPS compared with reference plasma proteins and with apo A1 and apo B100 representing high and low density lipoproteins. After 15 min of centrifugation, 84 +/- 2% (mean +/- SE) of the recovered LPS were found in the lower one-third of the centrifuged volume, whereas 6 +/- 1% remained in the upper one-third volume, indicating that meningococcal endotoxin circulates as complexes with high sedimentation coefficients. Bacterial outer membrane fragments were detected in the bottom fractions of three patient plasmas examined by means of electron microscopy. In three patient plasmas ultracentrifuged for 60 min at 103,000 g, the levels of apo A1 and apo B100 revealed minor changes, whereas only 1 +/- 1% of the recovered LPS remained in the upper one-third and 91 +/- 2% were found in the lower one-third volume. Few bioreactive LPS appear to be complexed with high and low density lipoproteins in meningococcal septic shock plasma.

Endotoxins↗
PubMed1998

Relationship of endotoxin to tumor necrosis factor-alpha and interleukin-1 beta in children with otitis media with effusion.

Sixty-five middle ear effusions and paired sera from 41 children with chronic otitis media with effusion were assayed for endotoxin and for tumor necrosis factor alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) in order to establish whether a correlation exists between the concentrations of endotoxin and of these cytokines. Endotoxin concentration was determined by means of a chromogenic limulus amebocyte lysate assay, and the cytokine concentration by means of a quantitative enzyme-linked immunosorbent assay. Forty percent of the effusions had detectable levels of endotoxin, with a mean concentration of 2.9 +/- 7.8 endotoxin units per milligram of total protein. The mean concentration of TNF-alpha was 1.24 +/- 3.1 pg/mg total protein, and that of IL-1 beta was 18.79 pg/mg total protein. A strong, statistically significant correlation exists between the concentrations of endotoxin and TNF-alpha (r = .89) and IL-1 beta (r = .72). The data indicate that endotoxin may contribute to the pathogenesis of chronic otitis media with effusion by stimulating the sustained production of TNF-alpha and IL-1 beta in the middle ear.

Child↗
PubMed1980

Endotoxic activity in teeth with necrotic pulps.

From root canals of 13 teeth with necrotic pulps, samples were taken for analysis of endotoxin content by means of the Limulus by lysate technique. The results were related to the viable bacteria count of root canal samples, phenol/water-extracted lipopolysaccharides (LPS) from different gram-negative anaerobic bacteria, and to different fractions of inflammation exudate. It was found that the endotoxic activity of the root canal samples was correlated with the presence and the number of gram-negative bacteria in the root canal.

Adolescent↗
PubMed2000

Plasma endotoxin concentrations during cardiac surgery may be related to atherosclerosis.

Systemic endotoxemia develops during cardiopulmonary bypass, probably due to intestinal ischaemia. Differences in endotoxaemia among various cardiac operations and the relationship between endotoxemia and postoperative complications were studied in high-risk patients. Blood samples were obtained at termination of bypass in 136 adults undergoing elective cardiac surgery. Postoperative complications were registered prospectively. Plasma endotoxin was quantified by a kinetic limulus amebocyte lysate assay. Mean endotoxin concentrations were significantly lower in patients undergoing isolated valve replacement (89 ng/l) than in patients undergoing coronary artery bypass grafting alone (234 ng/l), or combined with valve replacement (278 ng/l) or carotid artery surgery (321 ng/l) (p < 0.05). In multivariate linear regression, only the number of grafts (0, 1-3, 4-5) was significantly correlated to endotoxin concentrations (p < 0.0005). Endotoxin concentrations were related to development of gastrointestinal dysfunction (p = 0.03), but not to mortality (p = 0.24) or other complications (p = 0.62).

Aged↗
PubMed2000

Endotoxin in pooled pericardial blood contributes to the systemic inflammatory response during cardiac surgery.

Although endotoxin has been implicated as an important contributor to the systemic inflammatory response (SIR) during cardiopulmonary bypass (CPB), its source remains unclear. While gut translocation has traditionally been perceived as the primary source of endotoxemia, accumulation of endotoxin in pooled pericardial blood may represent an additional source of endotoxin that is continually reinfused into the CPB circuit. Eighteen patients undergoing primary coronary revascularization procedures were prospectively evaluated. Shed blood pooled in the pericardial space was returned to the CPB circuit through cardiotomy suction catheters at 45 min after placement of the aortic cross-clamp. Simultaneous samples of pooled pericardial and peripheral arterial blood were obtained and analyzed by a limulus amebocyte lysate assay for the determination of endotoxin concentration, and an enzyme-linked immunosorbent assay for tumor necrosis factor (TNF-alpha) levels. Significant elevations in endotoxin were demonstrated in pooled pericardial blood samples compared with arterial blood (3.5 +/- 0.5 vs 0.8 +/- 0.2 pg/ml; p < 0.05). TNF-alpha levels were below the limits of detection in both samples. These data implicate pooled pericardial blood as an important primary source of endotoxin that, when continually reinfused throughout CPB, may contribute to the overall SIR. Because endotoxemia has been identified as an important predictor of adverse outcomes following cardiac surgery, removal of endotoxin antigen in shed pericardial blood, prior to its reinfusion into the CPB circuit, may provide a directed means to improve perioperative outcome without compromising established blood conservation techniques.

Adult↗
PubMed1995

Endotoxaemia detected during cardiopulmonary bypass with a modified Limulus amoebocyte lysate assay.

Cardiopulmonary bypass (CPB) is associated with blood heparin level fluctuations and a reduction in haematocrit due to crystalloid haemodilution. The effect of these changes on the reliability of the Limulus amoebocyte lysate (LAL) chromogenic microassay for the measurement of plasma endotoxin was assessed in vitro. It was shown that the assay could be significantly compromised by twofold haemodilution which can occur during CPB. The interference effect on the assay caused by CPB-associated heparin was not significant if a comparatively large amount of heparin (25 IU/ml) was added to the blood at the time of sampling. The effect of haemodilution was counteracted by prediluting plasma samples with crystalloid by a factor dependent on the sample haematocrit (to ensure that the proportion of plasma was similar in all samples). A correction was then required to determine the endotoxin level in the original sample. The modified assay was used to determine sequential plasma endotoxin levels in 14 patients undergoing hypothermic nonpulsatile CPB. Endotoxaemia occurred at the time of aortic cross-clamp release and reached a peak of 48.9 +/- 12.9 ng/l shortly before the end of CPB, which was significantly higher than baseline values pre-CPB (p < 0.05). Thereafter, there was a decline in endotoxin levels to 28.9 +/- 13.6 ng/l 24 hours later which was still significantly higher than baseline levels (p < 0.05). Peak endotoxaemia was a predictor of protracted hospital stay when compared with haemodynamic and tissue perfusion parameters.

Cardiopulmonary Bypass↗
PubMedDate not supplied

A study of endotoxaemia in patients with primary biliary cirrhosis.

Hepatic reticuloendothelial function may be diminished in patients with primary biliary cirrhosis. Endotoxin concentrations in peripheral blood and in the superior mesenteric vein were measured, by the beta-glucan sensitive, factor-free, endotoxin-specific limulus assay, in patients with primary biliary cirrhosis and liver cirrhosis (non-PBC cirrhosis). Endotoxaemia was detected in the peripheral blood of seven out of nine patients (78%) with asymptomatic primary biliary cirrhosis, but in only two out of thirteen patients (15%) with non-PBC cirrhosis. The endotoxin level was significantly higher in the earlier stages of primary biliary cirrhosis than in the later stages (P < 0.05). The endotoxin level in superior mesenteric vein blood was significantly lower in patients with primary biliary cirrhosis than in patients with non-PBC cirrhosis. Peripheral endotoxaemia in patients with primary biliary cirrhosis may be due to the diminished capacity of the hepatic reticuloendothelial system, for phagocytosis of endotoxin.

Endotoxins↗
PubMed2003

Endotoxins in ophthalmic viscosurgical devices.

PURPOSE: To measure the endotoxin concentration (EC) of 25 commercially available, hyaluronic acid- and hydroxypropylmethylcellulose-based (HPMC) ophthalmic viscosurgical devices (OVDs). METHODS: The in vitro Limulus amebocyte lysate (LAL) assay, which indicates the presence of endotoxins originating from gram-negative bacteria, was used to determine the EC. The procedure was performed according to the European Pharmacopoeia/USP. EC including duplicate determinations, negative controls, dilution series with control standard endotoxin, dilution series with sample extract and positive sample control. RESULTS: 16 OVDs (Amvisc, Amvisc Plus, Biolon, Coatel, Healon, Healon GV, Healon, HPMC Ophtal L, Microvisc, Microvisc Plus, Ocucoat, Provisc, Rayvisc, Viscoat, Visco Shield 2%, Visko 1.4%) had an EC under 1.2 endotoxin units/mL, five (Adatocel, HPMC Ophtal H, LA Gel, Viscorneal, Viscorneal Plus) had an EC > or = 1.2 and < or = 24 EU/ml, and four (Biocorneal, Dispasan also named Ophthalin, Dispasan Plus, Visko 1%) had an EC of > 24 EU/ml. DISCUSSION: To avoid viscoelastic-related inflammatory or immunological reactions, the use of pure OVDs is recommended, especially for surgical procedures with an inherent possibility of leaving viscoelastic remnants in the eye (e.g., cataract surgery, visco-canalostomy or penetrating keratoplasty).

Endophthalmitis↗
PubMed1988

A novel immunohistochemical method for in vivo detection of endotoxin using horseshoe crab factor C.

We developed a novel immunohistochemical method for in vivo detection of endotoxin (LPS) localization in relation to the biologically active region, by use of factor C, an initiation factor in the Limulus clotting system which is mediated by LPS, as a specific affinoligand to LPS, and using rabbit anti-factor C IgG. The competitive inhibition of various LPS, lipid A, anti-LPS factor, or polymyxin B to factor C binding indicates that the immunohistochemical reaction is specific to LPS. Investigating the time course of LPS distribution during 6 hr after IV injection of 5 mg/kg to rats, the greatest uptake of LPS was evident in the reticuloendothelial system (RES), particularly in Kupffer cells, 5 min after injection, and in adrenocortical cells 3 hr after the injection. Shortly after the injection, LPS also appeared in platelet thrombi, intravascular monocytes, and a few neutrophils, and on the surface of endothelial cells in liver, kidney, spleen, lung, and aorta. Both smooth and rough forms of LPS were detectable and there was no apparent difference in their localization. This approach facilitates immunohistochemical analyses of the mechanisms involved in development of endotoxemia.

Adrenal Glands↗
PubMed2003

Effects of bacterial cell wall components (PAMPs) on the expression of monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1alpha (MIP-1alpha) and the chemokine receptor CCR2 by purified human blood monocytes.

Regulation of chemokine production and the expression of chemokine receptors play an important role during inflammation and infectious diseases. The present study was designed to study the effects of five different bacterial cell wall components (PAMPs) on the production of MCP-1 and MIP-1alpha and the expression of CCR2 by highly purified human blood monocytes. All five PAMPs induced high expression of mRNA and protein synthesis of both chemokines. Generally, MCP-1 mRNA and protein levels were higher than MIP-1alpha levels. Expression of MCP-1 and MIP-1alpha differed both at the mRNA and at the protein levels, MIP-1alpha always showing a more rapid initial increase, attaining lower protein levels than MCP-1. Antibodies against CD14 significantly inhibited the inducing effects of all the PAMPs used. Antibody against TLR2 inhibited the chemokine production induced by LTA and AraLAM by more than 36% (P < 0.05) while chemokine production induced by Escherichia coli-LPS, purified E. coli-LPS and Neisseria meningitidis-LPS was inhibited by more than 60% by antibody against TLR4 (P < 0.05). The inducing effects of all five PAMPs could be inhibited by rIL-4, rIL-10 and rIL-13. rIL-4 was the most effective. Generally, IC(50) of these anti-inflammatory cytokines were lower for the MIP-1alpha than for the MCP-1 production. The cell surface expression of CCR2 was significantly down-regulated by all five PAMPs in addition to a decrease in cytosolic free calcium and binding of rMCP-1. We conclude that MCP-1 and MIP-1alpha as well as the MCP-1 receptor CCR2 will be substantially regulated upon monocyte contact with various cell wall components (PAMPs) from Gram-negative and Gram-positive bacteria as well as from mycobacteria.

Antibodies, Monoclonal↗
PubMed2002

Different acute-phase response in newborns and infants undergoing surgery.

In a prospective clinical study, we investigated the inflammatory response in 88 neonatal subjects (43 boys and 45 girls) who underwent major abdominal surgery owing to congenital malformation involving the gastrointestinal tract and compared it with the response in 20 infants (8 boys, 12 girls; mean age, 4 mo) who underwent elective surgery for resolution of an existing temporary stoma. In both groups, plasma levels of endotoxin, IL-6, and C-reactive protein as well as leukocyte counts were determined during and after surgery. Endotoxin was measured by the Limulus amebocyte test, IL-6 by ELISA, and C-reactive protein by nephelometry. Statistical analyses were performed using the Wilcoxon signed-rank test. A significant increase in circulating endotoxin and a leukocyte shift was observed in the infant group only. Postoperatively, IL-6 levels peaked between 2 and 6 h and C-reactive protein after 24 h in the infant group. In contrast, no significant increase in the levels of endotoxin, IL-6, and C-reactive protein in plasma were observed during and after surgery in the neonatal subjects, except those with gastroschisis. Newborns with gastroschisis developed an inflammatory response after surgery that was less pronounced than the response of infants older than 4 mo. The finding that endotoxemia in newborns does not follow surgical trauma is most likely because of the absence of bacterial colonization of the gastrointestinal tract.

Abdomen↗
PubMed2001

Antitumor beta glucan from the cultured fruit body of Agaricus blazei.

Agaricus blazei is a medically important mushroom widely eaten and prescribed in Japan. Polysaccharide fractions were prepared from cultured A. blazei by repeated extraction with hot water (AgHWE), cold NaOH (AgCA), and then hot NaOH (AgHA). By chemical, enzymic, and NMR analyses, the primary structures of AgHWE, AgCA, and AgHA were mainly composed of 1,6-beta-glucan. Among these fractions, the NaOH extracts showed antitumor activity against the solid form of Sarcoma 180 in ICR mice. To demonstrate the active component in these fractions, several chemical and enzymic treatments were applied. These fractions were found to be i) neutral beta-glucan passing DEAE-Sephadex A-25, ii) resistant to periodate oxidation (I/B) and subsequent partial acid hydrolysis (I/B/H), iii) resistant to a 1,3-beta-glucanase, zymolyase, before I/B, but sensitive after I/B/H. In addition, after I/B/H treatment of the neutral fraction of AgCAE, a signal around 86 ppm attributable to 1,3-beta glucosidic linkage was detectable in the 13C-NMR spectrum. These facts strongly suggest that a highly branched 1,3-beta-glucan segment forms the active center of the antitumor activity.

Agaricus↗
PubMed1986

Characterization of the pyrogenicity of two different lipopolysaccharides and their lipid A-bovine serum albumin complexes.

In order to elucidate the dependency of pyrogenicity of lipopolysaccharide (LPS) on the lipid A structure, we investigated the pyrogenicity of both LPS and lipid A prepared from Mima polymorpha var. oxidans which is deficient in 3-hydroxymyristic acids linked to the 3-hydroxy group of other fatty acids. LPS and lipid A were also prepared as reference compounds from Escherichia coli UKT-B. Furthermore, the establishment of reliable indices for pyrogenicity was undertaken. The following results were obtained. The correlation in linearity was demonstrated between maximal increase in body temperature (delta Tmax) and dose of LPS or lipid A complexed with bovine serum albumin (BSA). The dose-response curves based on delta Tmax were more reliable statistically than the Fever Index-4h representing the area under fever curves for 4 h. The minimum pyrogenic dose (MPD) of E. coli LPS was 1.6 X 10(-3) micrograms/kg i.v. In contrast, the MPD of M. polymorpha LPS was 7.0 X 10(-3) micrograms/kg i.v. By intracisternal injection, the MPD of E. coli LPS was 2.5 X 10(-6) micrograms/kg and that of M. polymorpha LPS 1.0 X 10(-4) micrograms/kg. The end points of Limulus amoebocyte lysate gelation were 10(-5) micrograms/ml in E. coli LPS and 10(-3) micrograms/ml in M. polymorpha LPS. The MPDs of lipid A/BSA complexes by i.v. injection were 0.15 micrograms/kg in E. coli and 2.5 micrograms/kg in M. polymorpha. The rabbits immunized with E. coli lipid A/BSA complex acquired pyrogenic tolerance to the parent LPS but the cross tolerance to M. polymorpha LPS was not observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Acinetobacter↗