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PubMed2002

Endotoxin-induced changes in food consumption in healthy volunteers are associated with TNF-alpha and IL-6 secretion.

This study examined the effects of endotoxin administration on food and water consumption in humans, and the associations between these changes and endotoxin-induced secretion of cytokines, cortisol, and fever. Twenty healthy male volunteers received an i.v. injection of Salmonella abortus equi endotoxin (0.8 ng/kg) or saline in two experimental sessions. Blood samples were collected hourly, and rectal temperature was monitored continuously. Food consumption was significantly reduced at 0-4 h and significantly elevated at 4-5 h after the endotoxin injection. Endotoxin administration had no significant effect on water consumption. Endotoxin-induced secretion of TNF-alpha and IL-6 was positively associated with the decrease in food consumption (r=0.61 and 0.68), and negatively associated with the rebound increase in food consumption (r=-0.53 and -0.45). Neither the febrile response, nor the secretion of cortisol was associated with the changes in food consumption. These results suggest that TNF-alpha and IL-6 are involved in endotoxin-induced anorexia in humans.

Adult↗
PubMed1985

Quantitative determination of bacterial endotoxin in middle ear effusions by chromogenic substrate method.

It is known that bacterial endotoxin on the outer surface of most gram-negative bacteria (GNB) is not only biologically active material, but also the modulator of the immune response. The earlier experiment documented that the endotoxin of killed Haemophilus influenzae was responsible for induction of chronic otitis media with effusion (OME). Recent study by DeMaria et al. determined the endotoxin of human middle ear effusion (MEE) by means of limulus amebocyte lysate assay. It was concluded the endotoxin was present in a high percentage of the effusion in human tympanic cavities. The present study was undertaken to quantitatively determine the endotoxin in human MEE by use of chromogenic substrate technique which is more sensitive and accurate than limulus assay. Sixty samples of mucoid and serous effusion were subjected to chromogenic substrate method. It was revealed that the mucoid effusion showed a significantly high level of endotoxin at 282 pg/ml in average, though the serous effusion contained only 35.9 pg/ml. It is assumed that the bacterial endotoxin may greatly contribute to the pathogenesis of otitis media with mucoid effusion.

Adolescent↗
PubMed2002

Adherent endotoxin mediates biological responses of titanium particles without stimulating their phagocytosis.

Aseptic loosening of orthopaedic implants is thought to be primarily due to stimulation of cytokine production by wear particles from the implants. The cytokines increase osteoclast differentiation, leading to osteolysis and implant loosening. Accumulating evidence indicates that adherent endotoxin mediates the biological responses induced by the wear particles. One mechanism by which adherent endotoxin may act is by increasing phagocytosis of the wear particles. To test this hypothesis, the effect of adherent endotoxin on phagocytosis of titanium particles was determined. First, we developed reliable confocal and fluorescence microscopy methods to examine both the attachment and internalization steps of phagocytosis. Use of these methods showed that adherent endotoxin does not detectably alter the rate or the extent of phagocytosis of titanium particles by RAW 264.7 cells. Despite this lack of an effect on phagocytosis, adherent endotoxin dramatically increases the ability of RAW 264.7 cells to produce TNF-alpha and induce osteoclast differentiation. Thus, adherent endotoxin mediates these biological responses by a mechanism that does not rely on increased phagocytosis. These results also demonstrate that phagocytosis is not sufficient to induce cytokine production and osteoclast differentiation but do not rule out the possibility that phagocytosis is required for induction of these responses by titanium particles with adherent endotoxin.

Animals↗
PubMed2000

Study of the effects of vacuuming on the concentration of dust mite antigen and endotoxin.

BACKGROUND: Dust mite antigens are major sources of allergens in house dust and together with endotoxin, a proinflammatory component of gram negative bacteria also found in house dust, are important causes of tissue injury involved in the pathogenesis and severity of allergic diseases, eg, asthma. OBJECTIVE: To determine the effectiveness of vacuuming in reducing the quantity of dust mite antigens, Dermatophagoides pteronyssinus (Der p and Der p2) and endotoxin using a quantitative ELISA assay and to correlate results with those obtained using a qualitative rapid dipstick method for Der p2. METHODS: Four specimens of house dust were collected using a Kirby Model G5 vacuum cleaner with a Micron Magic Filtration system from an approximately 54" x 18" standardized area of rug from each of 20 homes at 4 time intervals over a 6-week period, ie, a baseline specimen #1 at 0 week; specimen #2 at 1 week; specimen #3 at 5 weeks (1 month after specimen #2); specimen #4 at 6 weeks (1 week after specimen #3). Three intervals were compared, ie, period 1-2 (1 week), period 2-3 (1 month), and period 3 to 4 (1 week). The concentrations of Der p1 and Der p2 were determined in dust samples using a standard ELISA assay and the concentration of endotoxin was detected using a limulus amebocyte lysate assay. Concentrations of Der p2, determined by the standard ELISA assay, were compared to those in the same samples determined by a rapid dipstick method. RESULTS: A wide range of values for total weight of unprocessed dust (0.3 to 59 g, X = 8.7) and finely sieved dust (0.1 to 19 g, X = 3) from all specimens were found. In finely sieved dust specimens the mean concentrations of Der p1, Der p2 and endotoxin were 775, 1310, and 3836 ng/g of dust, respectively. Following weekly vacuuming there was an increase in concentration of Der p1, Der p2, and endotoxin in 20%, 35%, and 63% of the houses, respectively, compared to in monthly vacuuming in which increases were seen in 65%, 50%, and 63% of the houses, respectively. In contrast, there was a decrease in concentration of Der p1, Der p2 and endotoxin with weekly vacuuming in 43%, 60%, and 37% of the houses respectively versus in monthly vacuuming in 15%, 35%, and 37% of the houses respectively. A correlation coefficient of 0.7 was found for the concentration of Der p2 in 37/40 samples tested detected using the ELISA method compared with rapid dipstick assay. CONCLUSION: The results of this study support the effectiveness of vacuuming on the reduction of dust mite antigens (Der p1 and Der p2) ie, Der p2 > Der p1. This reduction was more pronounced with weekly compared with monthly vacuuming. No reduction in the concentration of endotoxin was found. A good correlation was found between results obtained by ELISA and rapid dipstick assay for Der p2.

Air Pollution, Indoor↗
PubMed2003

Invasive assessment of bacterial endotoxin and inflammatory cytokines in patients with acute heart failure.

AIMS: To test the hypothesis that during acute heart failure endotoxin might be increased in hepatic veins as a sign of bacterial or endotoxin translocation from the bowel into the blood stream. METHODS AND RESULTS: In patients with acute heart failure (NYHA IV; n=17) levels of endotoxin, soluble (s) CD14, tumor necrosis factor alpha (TNFalpha and interleukin 6 (IL6)) were measured in blood drawn from an antecubital vein on admission and compared with age-matched patients with stable chronic heart failure (n=21) and healthy volunteers (n=9). All levels were systemically elevated during acute heart failure (all P<0.05); once patients were stable enough to undergo cardiac catheterization, endotoxin was found to be significantly higher in hepatic veins (0.62+/-0.05 EU/ml) than left ventricles (0.46+/-0.04 EU/ml; P<0.05), whereas sCD14, TNFalpha and IL6 were not different between these sites. At follow-up (29+/-6 days) endotoxin but not sCD14, TNFalpha or IL-6 was significantly lower as compared to baseline (P<0.05). CONCLUSIONS: Higher levels of endotoxin in hepatic veins as compared to the left ventricle during acute heart failure are suggestive of bacterial or endotoxin translocation from the bowel into the blood stream. This may lead to new treatment strategies. The lack of difference in TNFalpha levels between the pulmonary artery and the left ventricle sheds doubt on the heart as a source of systemically elevated TNFalpha levels.

Aged↗
PubMed2006

[Analysis of the impurity of bacterium source of standard endotoxin by gas chromatography/mass spectrometry].

To analyse the impurity of bacterium source of standard endotoxin, 3-hydroxy fatty acid species in different endotoxin standards was determined by gas chromatography/mass spectrometry (GC/MS) using N, O-bis (trimethylsilyl) trifluoroacetamide as the silanizing reagent. GC/MS analysis was performed using a gas chromatograph equipped with a 60 m x 0.25 mm i. d. DB-5 fused silica capillary column and an injector at 250 degrees C. Helium was used as the carrier gas under a constant pressure of 206 kPa. The oven was programmed at a rate of 5 degrees C /min from 90 degrees C (held for 5 min) to 280 degrees C (held for 5 min). The sample size was 1 microL. The transfer line was kept at 280 degrees C. The quadrupole mass spectrometer was operated in electron impact (EI) ionization mode, and the temperature of the source was kept at 250 degrees C. The kind of 3-hydroxy fatty acids in 9 000 EU/tube national standard endotoxin, 20 EU/tube working standard endotoxin, Escherichia coli, Pseudomonas aeruginosa and deionized water were determined to study the purity of bacterium source of the standard endotoxin. It was shown that 9 000 EU/tube endotoxin standard and Escherichia coli only contained 3-hydroxytetradecanoic acid. There was 3-hydroxydodecanoic acid in 20 EU/tube working standard endotoxin, which indicated the presence of impurity of bacterium source.

Bacteria↗
PubMed1999

Transition state of the rate-limiting step of heat denaturation of Cry3A delta-endotoxin.

Heat denaturation of Cry3A delta-endotoxin from Bacillus thuringiensis var. tenebrionis and its 55 kDa fragment was studied by differential scanning microcalorimetry at low pH. Analysis of the calorimetric data has shown that denaturation of Cry3A delta-endotoxin is a nonequilibrium process at heating rates from 0. 125 to 2 K/min. This means that the stability of delta-endotoxin (the apparent temperature of denaturation Tm) under these conditions is under kinetic control rather than under thermodynamic control. It has been shown that heat denaturation of this protein is a one-step kinetic process. The enthalpy of the process and its activation energy were measured as functions of temperature. The data obtained allow confirmation of the fact that the conformation of delta-endotoxin at the transition state only slightly differs from its native conformation with respect to compactness and extent of hydration. The comparison of the activation energy for intact delta-endotoxin and the 55 kDa fragment showed that the transition of the molecule to a transition state does not cause any changes in the conformation of three N-terminal alpha-helices. Complete removal of the N-terminal domain of delta-endotoxin and 40 amino acids from the C-terminus beta-sheet domain III causes an irreversible loss of the tertiary structure. Thus, during protein folding the nucleation core determining protein stability does not involve its three initial alpha-helices but may include the remaining alpha-helices of the N-terminal domain. The functional significance of peculiarities of structure arrangement of the delta-endotoxin molecule is discussed.

Bacillus thuringiensis↗
PubMed2000

Endotoxin (lipopolysaccharide)-induced nitric oxide production in 2,3,7,8-tetrachlorodibenzo-p-dioxin-treated Fischer rats: detection of nitrosyl hemoproteins by EPR spectroscopy.

Electron paramagnetic resonance (EPR) spectroscopy was used to study the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on endotoxin (lipopolysaccharide)-induced nitric oxide (NO) production in Fischer rats. We found that rats treated with 50 microg/kg TCDD had increased sensitivity to endotoxin, resulting in an approximately 2-fold increase in the level of NO production detected as nitrosylhemoglobin (HbNO) in venous blood. At lower concentrations (< or = 5 microg/kg), TCDD did not affect the endotoxin-induced NO production. The TNF-alpha serum concentration was found to parallel that of NO. TCDD alone did not induce the production of detectable HbNO or TNF-alpha. We found that TCDD induced a dose-dependent increase in the EPR signal intensity of (Fe(3+)) low-spin methemoprotein complexes found in the liver and kidney. These species with EPR resonance at g = 2.43, 2.26, and 1.92 are attributed to low-spin Fe(3+) in cytochromes P450 and P420. Our data confirm previous studies that have shown that TCDD induces a dose-dependent increase in the production of some cytochrome P450 enzymes. However, in rats that were subsequently challenged with endotoxin, a smaller increase in the EPR intensity of these species was observed. The decrease in the low-spin Fe(3+) cytochrome P450 EPR signal in endotoxin-challenged rats could be due to one or more of the following occurring: (1) cytochrome destruction, (2) reduction of the ferric to the ESR-silent ferrous oxidation state of cytochromes by nitric oxide, and/or (3) formation of ferrous nitrosyl cytochrome complexes that contribute, in part, to the characteristic five-coordinate nitrosyl hemoprotein triplet also observed in these tissues. Since low concentrations of endotoxin can leak from the gut lumen into the systemic circulation, this investigation explores the possibility that endotoxin interaction with TCDD may be, in part, responsible for the effects of TCDD observed in these tissues.

Animals↗
PubMed2002

IgA against gut-derived endotoxins: does it contribute to suppression of hepatic inflammation in alcohol-induced liver disease?

Endotoxins of intestinal origin are supposed to play an important role in the development of alcoholic hepatitis in man. To estimate the role of immunoglobulin response to gut-derived endotoxin in the development of alcohol-induced liver disease, serum levels of IgA and IgG against fecal endotoxin, endotoxin, and acute-phase proteins were measured in patients with different stages of alcoholic liver disease and in healthy controls. Antibodies of type IgA, but not IgG, against fecal endotoxins were significantly increased in patients with alcohol-induced liver disease. IgA antibodies against fecal endotoxin were found to be closely correlated with the plasma concentrations of alanine aminotransferase, gamma-glutamyl transferase, and C-reactive protein in patients with alcoholic liver disease. In conclusion, as IgA located in body tissue was shown to suppress the inflammatory process, enhanced production of IgA against endotoxin of intestinal origin may contribute to inactivation of this compound, thereby reducing its damaging effect on the liver.

Adult↗
PubMed1992

Beneficial effects of endotoxin treatment on metabolism in tumour-bearing rats.

The effects of endotoxin treatment on host metabolism in tumour-bearing rats were investigated. Metabolism in control rats (non-tumour-bearing) was slightly altered by endotoxin treatment, whereas in tumour-bearing rats a number of biochemical parameters that were initially perturbed by the presence of the tumour had returned to normal at 48 h post-treatment. The beneficial effects included increased blood glucose and insulin concentrations, and decreased ketone body, triglyceride and lactate concentrations. Potentially non-beneficial effects of endotoxin observed in both tumour-bearing and control rats included decreased plasma cholesterol, and increased plasma phosphate, potassium and alkaline phosphatase levels. Endotoxin caused haemorrhaging in the encapsulated tumour, and this was associated with histological evidence of endothelial damage, red cell infiltration into surrounding tumour tissue and a marked decrease in cell viability. The in vivo uptake of glucose by the tumour, measured by 2-deoxy [U-14C]glucose uptake, was decreased by 96% following endotoxin treatment, and this was associated with a two-fold increase in glucose uptake by muscle. It is concluded that endotoxin treatment has major effects on cell viability and the integrity of vasculature in the tumour, which limits glucose uptake by the tumour and thereby decreases the energy and substrate requirements of the tumour, thus benefiting the host. It is suggested that tumour cytotoxicity and intra-tumour haemorrhage are the result of endotoxin stimulating cytokine release from macrophages that are already activated by the presence of the tumour.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1978

Study of chemical sympathectomy in endotoxin-induced lethality and fibrin depostion.

Shock and the generalized Shwartzman reaction are well known features of endotoxin which have been shown to involve the sympathetic nervous system. The mechanism of sympathetic nervous system involvement with endotoxin injection was studied in rabbits chemically sympathectomized with 6-hydroxydopamine. Endotoxin, in doses producing a spectrum of morbidity and mortality in normal rabbits, was administered i.v. to chemically sympathectomized, normal, and unilateral renal surgically sympathectomized animals. Chemical sympathectomy produced a significant depletion of tissue norepinephrine which, in endotoxin recipient animals, was associated with a significantly lower mortality rate and greatly decreased fibrin deposition in the lungs and kidneys, despite intravascular coagulation. Unilateral renal sympathectomy afforded protection to the ipsilateral kidney, but data on mortality and systemic fibrin deposition were similar to those reported for normal rabbits given endotoxin. Six-hydroxydopamine prevents significant tissue injury secondary to endotoxin in this experimental model. In addition, the data provide direct evidence that an intact reactive sympathetic nervous system is essential for development of lethal toxicity and generalized Shwartzman reaction due to endotoxin.

Animals↗
PubMed1997

Influence of endotoxin contamination on anti-GBM antibody induced glomerular injury in rats.

It is accepted that the main determinant of glomerular injury in experimental nephrotoxic nephritis is the administered dose of anti-glomerular basement membrane (GBM) antibody. However, there are other factors that can enhance the severity of such injury including small doses of bacterial lipopolysaccharide (LPS). In the present study, we have assessed whether preparations of anti-GBM antibody contaminated with different concentrations of endotoxin could influence the severity of glomerular injury in the heterologous phase of nephrotoxic nephritis. We have also examined the efficacy of different laboratory methods to isolate an endotoxin-free anti-GBM antibody, and to purify anti-GBM antibody preparations from endotoxin. Preparations of anti-GBM antibody (nephrotoxic globulin) isolated from nephrotoxic serum by the sodium sulphate precipitation method contained variable concentrations of endotoxin. Administration of these preparations in equal doses into clean rats, which had no established acute phase response, markedly aggravated the severity of glomerular injury. However, preparations contained less than 50 pg/ml of endotoxin appeared to have no significant effect on such injury. Furthermore, isolation of anti-GBM antibody from nephrotoxic serum by affinity chromatography, using Staphylococcus protein-A column, proved to be a reliable method not only for the isolation of an IgG (nephrotoxic antibody) free from other serum contaminants, but also for purification of endotoxin contaminated preparations of anti-GBM antibody. These observations have practical implications in studying models of nephritis as our results show that the glomerular injury, which is usually considered to be a sole function of the mass of antibody bound to GBM, is profoundly influenced by minor endotoxin contamination of the anti-GBM antibody.

Animals↗
PubMed1997

Hyperdynamic circulation of cirrhotic rats with ascites: role of endotoxin, tumour necrosis factor-alpha and nitric oxide.

1. Hyperdynamic circulation observed in portal hypertensive states is characterized by generalized vasodilation, increased cardiac index and increased systemic and regional blood flows. Endotoxin, tumour necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) have been reported to be involved in the pathogenesis of hyperdynamic circulation, but the interactions between endotoxin, TNF-alpha and NO in cirrhotic rats with ascites have never been specifically addressed. 2. This study was designed to determine systemic and portal haemodynamics and plasma levels of endotoxin, TNF-alpha and nitrate/nitrite in cirrhotic rats with ascites and investigate the relationships between these substances. 3. Plasma concentrations of endotoxin, TNF-alpha and nitrate/nitrite (an index of NO production) were determined in 25 cirrhotic rats with ascites and 17 control rats using the Limulus assay, ELISA and a colorimetric assay respectively. In addition, haemodynamic studies were performed in another ten cirrhotic rats with ascites and ten control rats. 4. Cirrhotic rats with ascites had hyperdynamic circulation accompanied by increased plasma levels of endotoxin, TNF-alpha and nitrate/nitrite, as compared with control rats. Significant correlation existed between plasma levels of endotoxin and nitrate/ nitrite (r = 0.59, P < 0.0001) and between plasma levels of endotoxin and TNF-alpha (r = 0.63, P < 0.0001). No correlation was detected between plasma levels of TNF-alpha and nitrate/nitrite (r = 0.24, P > 0.05). 5. This study suggests that endotoxaemia developed in cirrhotic rats with ascites may stimulate NO formation directly or indirectly via cytokine cascade, and consequently participate in the development and/or maintenance of hyperdynamic circulation.

Animals↗
PubMed2002

Albumin synthesis in humans increases immediately following the administration of endotoxin.

In order to investigate the immediate (i.e. within 3 h) response of albumin synthesis to the administration of endotoxin, as a model of a moderate and well controlled catabolic insult, two measurements employing L-[(2)H(5)]phenylalanine were performed in 16 volunteers. One group ( n =8) received an intravenous injection of endotoxin (4 ng/kg; lot EC-6) immediately after the first measurement of albumin synthesis, whereas the other group received saline. A second measurement was initiated 1 h later. In the endotoxin group, the fractional synthesis rate of albumin was 6.9+/-0.6%/day (mean+/-S.D.) in the first measurement. In the second measurement, a significant increase was observed (9.6+/-1.2%/day; P <0.001). The corresponding values in the control group were were 6.6+/-0.6%/day and 7.0+/-0.6%/day respectively (not significant compared with first measurement and P <0.001 compared with the second measurement in the endotoxin group). The absolute synthesis rates of albumin were 148+/-35 and 201+/-49 mg x kg(-1) x day(-1) before and after endotoxin ( P <0.01). In the control group, the corresponding values were 131+/-21 and 132+/-20 mg x kg(-1) x day(-1) (not significant compared with the first measurement and P <0.01 compared with the second measurement in the endotoxin group). In conclusion, these results indicate that albumin synthesis increases in the very early phase after a catabolic insult, as represented by the administration of endotoxin.

Adult↗
PubMed2001

Pets and vermin are associated with high endotoxin levels in house dust.

BACKGROUND: Previous studies have shown that the risk for allergic sensitization is lower in children who grew up on farms and in young adults who were exposed to dogs in early childhood. A higher microbial exposure in general and in particular to endotoxin in early childhood might contribute to this lower risk of atopy. OBJECTIVE: We examined whether the presence of pets or vermin in the home is associated with higher endotoxin concentrations in settled house dust. METHODS: House dust was sampled in a standardized manner on the living room floors of 454 homes of German children aged 5-10 years (participation rate 61%). Endotoxin was assessed with a quantitative kinetic chromogenic Limulus Amebocyte Lysate (LAL) method. Associations between endotoxin levels, pets and vermin are presented as ratios of the crude and confounder adjusted geometric means (means ratios) in the category of study vs. a reference category using multiple linear regression models. RESULTS: Endotoxin concentrations in living room floor dust sampled in homes without pets and vermin were lower (1246 ng per square meter, 1519 ng endotoxin/g dust, n = 157) than those sampled in homes with pets or vermin (2267 ng per square meter, 2200 ng endotoxin/g dust, n = 296). After adjustment for city of residence, season of dust sampling, age of the building and story of the dwelling, means ratios for endotoxin expressed per gram of dust were statistically significantly increased for dog (1.64, 95% CI 1.09-2.46), for cat (1.50, 95% CI 1.03-2.18) and for cockroach (3.01, 95% CI 1.37-6.60), whereas no major statistically significant associations were found for other pets, ants and mice. CONCLUSION: Keeping a dog or a cat in the home is consistent with higher exposure to endotoxin and might therefore contribute to the lower risk of atopy in later life.

Air Pollution, Indoor↗
PubMed1998

Endotoxin release and cytokine production in acute and chronic meningococcaemia.

Chronic meningococcaemia is a relatively benign manifestation of meningococcal disease. Whether bacterial virulence factors are responsible for this benign course has not been studied. We compared the in vitro endotoxin-liberating ability and cytokine-inducing potential of 31 Neisseria meninigitidis isolates obtained from children with acute septic shock with that of nine isolates obtained from patients with chronic meningococcaemia and 12 isolates obtained from carriers with respiratory symptoms. The median endotoxin level released in vitro after 3 h of incubation was significantly higher for isolates causing septic shock compared with isolates from the other two groups (P=0.01 and 0.02, Mann-Whitney test). This was not explained by differences in bacterial growth rate in vitro. The median IL-6 levels in whole blood ex vivo after 4 h of incubation were also significantly lower for isolates causing chronic meningococcaemia (P=0.04, Mann-Whitney test). The endotoxin and cytokine levels measured on admission in the 31 children with acute meningococcal septic shock showed a 1000-fold variation. No relationship was established between the amount of endotoxin released by the causative microorganisms in vitro and the endotoxin or cytokine levels in the corresponding 31 children. These results suggest a diminished bacterial virulence for isolates causing chronic meningococcaemia. However, other factors than the endotoxin-releasing potential of the microorganism involved are responsible for the wide variation in endotoxin and therefore cytokine levels in patients with acute meningococcal septic shock.

Adolescent↗
PubMed2000

Endotoxin testing of proteins for parenteral administration using the Mono Mac 6 assay.

BACKGROUND: Pharmaceutical products containing proteins cause problems in testing for endotoxin and pyrogens. Many proteins interfere with the LAL test and the proteins are immunogenic in rabbits. The monocytic cell line Mono Mac 6 is an alternative assay for detection of endotoxin and other pyrogens. OBJECTIVE: To evaluate the use of the Mono Mac 6 assay for quantitative detection of endotoxin in proteins. METHOD: The quantitative detection of endotoxin in the three pharmaceutical products human albumin, gamma-globulin and somatropin was evaluated. RESULTS: For the three proteins the detection limit of the Mono Mac 6 assay was far below the threshold endotoxin limit described by the European Pharmacopoeia. Interference of two of the proteins with the Mono Mac 6 assay was observed, but the problems could be overcome either by dilution of the product or by comparison of the test with an endotoxin standard curve prepared in a solution of the respective pyrogen-free protein. CONCLUSION: The Mono Mac 6 assay is a reliable method for quantitative detection of endotoxin in proteins.

Administration, Oral↗
PubMed2002

Prevalence of symptoms, sensitization to rats, and airborne exposure to major rat allergen (Rat n 1) and to endotoxin in rat-exposed workers: a cross-sectional study.

OBJECTIVE: To analyse the relation between airborne exposure to major rat allergen and to endotoxins in exclusively rat-exposed workers and the prevalence of rat-related symptoms and sensitization. METHODS: A total of 113 workers answered a standardized questionnaire on their atopy status, occupational exposure to rats, and possible work-related symptoms. Specific IgE against rat urinary proteins (RUP) was measured for 73 subjects. Individual airborne exposure to Rat n 1 and endotoxin were determined with static (n = 256) samplings. Rat n 1 was measured with enzyme-linked immunosorbent assay (ELISA) and endotoxin by the Limulus method. RESULTS: Forty-four of 113 subjects (38.9%) reported at least one rat-related symptom: asthma (4.4%), rhinitis (34%) and conjunctivitis (16%). Twelve per cent were sensitized to RUP (specific IgE > 0.35 KU/L). But only 30.8% of all symptomatic subjects were sensitized to rat allergens. Airborne Rat n 1 levels were not related to symptoms in workers. Symptomatic patients not sensitized to rats were exposed to higher endotoxin levels, but airborne exposure to endotoxins did not significantly protect against or increase sensitization to RUP or rat-related symptoms. CONCLUSION: Most symptomatic workers were not sensitized to rat allergen; but no significant relation between rat-related symptoms and endotoxin levels was found. This suggests that more studies are needed to determine causes other than rat allergens or endotoxins that may be responsible for symptoms in rat-exposed workers.

Adult↗