Higher Endotoxin Concentrations Research Articles

Endotoxin emissions from commercial composting activities

This paper describes an exploratory study of endotoxin emissions and dispersal from a commercial composting facility. Replicated samples of air were taken by filtration at different locations around the facility on 10 occasions. Measurements were made of endotoxin and associated culturable microorganisms. The inflammatory response of cell cultures exposed to extracts from the filters was measured. Endotoxin was detected in elevated concentrations close to composting activities. A secondary peak, of lesser magnitude than the peak at source was detected at 100-150 m downwind of the site boundary. Unexpectedly high concentrations of endotoxin were measured at the most distant downwind sampling point. Extracted endotoxin was found to stimulate human monocytes and a human lung epithelial cell line to produce significant amounts of pro-inflammatory cytokines. On a weight basis, endotoxin extracted from the composting source has a greater inflammatory cytokine inducing effect than commercial E. coli endotoxin.

Toll-like receptor 4 variants reduce airway response in human subjects at high endotoxin levels in a swine facility

Toll-like receptor 4 (TLR4) variants have been shown to reduce the respiratory responses to inhaled LPS in controlled experiments among healthy volunteers. We sought to investigate whether naive subjects with TLR4 variants showed reduced respiratory response to a complex aerosol including endotoxin as a major constituent. Twenty-nine nonsmoking, nonatopic healthy subjects with TLR4 299/399 polymorphisms and 29 age- and sex-matched, wild-type TLR4 control subjects were exposed for 5 hours each in a noncontaminated environment (baseline day) and in a swine confinement facility (exposure day). There were 16 men and 13 women in each of the 2 age- and sex-matched groups. TLR4 polymorphic subjects who were exposed to high endotoxin levels (>or=1550 EU/m(3)) had less reduction in the percentage across-shift change in FEV(1) from baseline than did wild-type subjects exposed to similar endotoxin levels. Among subjects exposed to higher endotoxin levels, the mean differences in the percentage across-shift changes between baseline and exposure days were significantly less in TLR4 polymorphic subjects compared with those seen in wild-type subjects in FEV(1) (-8.48% +/- 1.52% [mean +/- SE] vs -11.46% +/- 1.79%, P = .001), forced expiratory flow between 25% and 75% of forced vital capacity (-18.30% +/- 1.99% vs -24.14% +/- 3.28%, P = .009), and FEV(1)/forced vital capacity ratio (-5.40% +/- 0.56% vs -8.53% +/- 1.51%, P = .04). These patterns were not observed in IL-6 levels from serum and nasal lavage fluid, IL-8 levels from nasal lavage fluid, white blood cell counts, or blood differential counts. The association between TLR4 variants and reduced airway responsiveness to inhaled particulate was observed at high endotoxin concentrations, creating the possibility of certain threshold phenomena for the apparent protective effect of TLR4 variants.

Concentrations of Bioaerosols, Odors, and Hydrogen Sulfide Inside and Downwind from Two Types of Swine Livestock Operations

Few data on in-barn and downwind concentrations of endotoxin, bioaerosols, and odors from livestock facilities are available, and no studies have compared conventional confinement operations with the more animal-friendly hoop operations. Hoops are open to the environment and use a composted bedding system rather than housing pigs on slatted floors over pits holding manure slurry as in conventional confinements. We assessed airborne toxicants upwind, in barns, and downwind and evaluated determinants of exposure. Inhalable particulate matter, endotoxin, odor threshold, hydrogen sulfide, culturable mesophilic bacteria, culturable fungi, and total airborne microbes, along with wind speed, temperature, and humidity were measured at separate midsized livestock facilities (one hoop, one confinement) in Central Iowa on 10 occasions over 2 years. Significant differences in contaminants were observed between hoops and confinement buildings and across seasons for endotoxin, odors, airborne microorganisms, and hydrogen sulfide. For hoops and confinements, respectively, geometric mean in-barn concentrations were 3250 and 3100 EU/m3 for endotoxin; 1400 and 1910 μg/m3 for particulates; 19.6 and 146 ppb for hydrogen sulfide; 137 and 428 dilutions for odor threshold; and 3.0 × 106 and 1.5 × 106 organisms/m3 for total microbes. Endotoxin, odor, and culturable microorganisms exceeded recommended exposure limits. Reduced analysis of variance models for these contaminants demonstrated differences by barn type, season, number of pigs, and, in some cases, temperature and humidity. Both types of swine operations produced high airborne concentrations of endotoxin, odor, hydrogen sulfide, bacteria, and fungi. Endotoxin and odors were found downwind at concentrations previously associated with adverse health effects.

Decreased Activity of Plasma ADAMTS13 Parallels Enhanced Endotoxemia in Patients with Severe Acute Pancreatitis: Relationship to Multiorgan Failure

Background: Severe acute pancreatitis (SAP) frequently progresses to pancreatitis-associated multiorgan failure (MOF) with high mortality. Decreased plasma ADAMTS13 activity (ADAMTS13:AC) results in the accumulation of unusually large von Willebrand factor multimers (UL-VWFM) and the formation of platelet thrombi, ultimately leading to MOF. We demonstrated that the imbalance between decreased ADAMTS13:AC and increased UL-VWFM could contribute to SAP pathogenesis through enhanced thrombogenesis, and serve as an early prognostic indicator for SAP patients (Scand J Gastroenterol , 2008, 26:1). Endotoxin has been considered to be the principle activator of the systemic inflammatory response syndrome, which predisposes patients for MOF and/or pancreatic necrosis, ultimately leading to SAP. We investigated the relationship of endotoxin to ADAMTS13:AC and its related parameters, and tried to explore their potential role on the development of MOF in patients with SAP.Methods: We sequentially determined plasma endotoxin concentration, ADAMTS13:AC and its related parameters in 13 SAP patients (APACHE-II score mean 6.6 ± 2.7), who were admitted into intensive care unit of our hospital between 2004 and 2006. Eleven patients were survivors and two were non-survivors whose APACHE II scores were 10 and 12 died of MOF, respectively. The degree of MOF was evaluated according to the SOFA score. Endotoxin concentration was determined by a chromogenic substrate assay (Toxicolor LS –M Set, Seikagaku Kogyo Co.) with kinetic analysis after pretreatment with detergent, Triton X-100, and heating at 70 °C for 10 min. Plasma ADAMTS13:AC was determined by a sensitive chromogenic ELISA (ADAMTS13-act-ELISA: Kainos Inc.). Plasma UL-VWFM was analyzed by a vertical SDS-1.0% agarose gel electrophoresis. Plasma VWF antigen (VWF:AG), interleukin 6 (IL-6), interleukin 8 (IL-8), and tumor necrosis factor -α (TNF-α) were measured by ELISA.Results: In normal healthy controls (n=20), plasma endotoxin concentration was 7.9±1.7 pg/ml (mean ± SD). The concentration in the SAP patients significantly increased at day 1 (means 65 pg/ml, p<0.001) and at day 2 (88 pg/ml, p<0.001) as compared to healthy controls. The values, thereafter, gradually decreased in 8 survivors (55 pg/ml at day 5, 53 pg/ml at day 7, 27 pg/ml at day 14), while in remaining 3 survivors needing necrosectomy, the concentration further increased (98 pg/ml at day 5, 178 pg/ml at day 7), and decreased to 20 pg/ml at day 14 at the recovery phase. In two non-survivors, the endotoxin levels increased from 37 pg/ml at day 1 to 462 pg/ml at day 2 in one needing necrosectomy, and showed 51 pg/ml at day 1 in another at the age of 91. Within 1 or 2 days after admission, the ADAMTS13:AC was lower in SAP patients (mean 29%, p<0.001) than in healthy controls (99%), and gradually recovered in the 11 survivors but further decreased in the 2 non-survivors. On admission, VWF:Ag was higher (402%, p<0.001) in SAP patients than controls (100%). VWF:Ag gradually decreased in the survivors, except in the 3 survivors needing a necrosectomy, but remained high in the non-survivors. UL-VWFM positive patients showed lower ADAMTS13:AC (25% vs. 42%, p<0.05) and higher VWF:Ag ( 481% vs. 332%, p<0.05), resulting in higher ratio of VWF:Ag to ADAMTS13:AC (25.2 vs. 9.1, p<0.02), as compared to UL-VWFM negative ones. Patients with higher endotoxin concentration more than 50 pg/ml showed lower ADAMTS13:AC than those without (22% vs. 43%, p<0.05). Plasma endotoxin concentration positively correlated with the ratio of VWF:Ag to ADAMTS13:AC (r=0.732, p<0.005). The SOFA score correlated positively with plasma endotoxin concentration (r=0.604, p<0.03), IL-8 (r=0.843, p<0.001), and the ratio of VWF:Ag to ADAMTS13:AC (r=0.700, p<0.01), and inversely with the ADAMTS13:AC (r= − 0.601, p<0.03).Conclusion. The imbalance between decreased ADAMTS13:AC and increased UL-VWFM is closely related to enhanced endotoxemia, which may contribute to the development of SAP and subsequent MOF through enhanced thrombogenesis.

Alternative water sources and endotoxin

The primary objective of this preliminary study was to ascertain the concentration of endotoxin in a variety of Australian water types, including recycled water. A total of 42 sampling sites were surveyed, the majority on at least 2 separate occasions (total number of samples analysed was 76). Samples were collected from a variety of locations throughout Australia including: drinking water distribution (12), drinking water reservoir (4), wastewater treatment train (11) and finished recycled water (15). Class A recycled waters, defined microbiologically in Australian regulations as having <10 E. coli per 100 mL, where the treatment train did not include membrane filtration, gave rise to an average measured endotoxin concentration of 2.030 Endotoxin Units (EU) per mL (N=7). For recycled Class A water samples, where membrane filtration was part of the treatment train (N=3) the average endotoxin concentration was 41 EU/mL. Measured endotoxin concentrations in drinking water varied from <4 to 119 EU/mL. Results of this preliminary study indicate that endotoxin concentrations in recycled water may be reduced to levels at least as low as those found in drinking water but for some recycled waters, where membrane filtration is not practiced, higher endotoxin concentrations may persist.

Endotoxin Exposure Is a Risk Factor for Asthma: The National Survey of Endotoxin in United States Housing

Thorne PS, Kulhankova K, Yin M, et al. Am J Respir Crit Care Med. 2005;172:1371–1377 PURPOSE OF THE STUDY. Studies have shown that endotoxin exposure associated with living in farm environments correlates with protection from atopy and asthma. Other studies offer conflicting data. The authors considered the possibility that regional sampling within the United States might explain such discrepancies. STUDY POPULATION. Household dust samples were assayed from 831 housing units that were selected as demographically representative of the 96 million homes in the United States. METHODS. Data gathered on all household occupants included diagnosed hay fever, diagnosed asthma, asthma symptoms in the past year, current asthma-medication use, and wheezing (ever, in the past month, and in the past year). Field-workers distributed questionnaires and collected dust samples, which were processed for endotoxin. Adjusted odds ratios (ORs) were calculated, controlling for census region, season, frequency of indoor cigarette smoking, education, poverty, race, ethnicity, presence of a ≤6-year-old child, and exposure to dust mite, cat, and dog allergens. RESULTS. The highest endotoxin concentrations were in dust from kitchen and living room floors (geometric means: 80.5 and 63.9 EU/mg, respectively). The lowest concentration was found in the bedding (18.7 EU/mg). In multivariate analysis, endotoxin exposure was significantly associated with multiple asthma outcomes, with the strongest for bedroom-floor and bedding endotoxin concentrations. No protective effects of endotoxin were seen. Instead, bedroom-floor–endotoxin concentrations above the first quartile (&amp;gt;16.6 EU/mg) had adjusted ORs of 1.95 to 2.78 for asthma symptoms in the past year, wheezing in the past month, and wheezing at any time compared with those in the first quartile. Similarly, bedding concentrations above the second quartile (&amp;gt;19.6 EU/mg) demonstrated adjusted ORs of 2.01 to 2.05 for wheezing at any time, in the past year, and in the past month compared with those in the first 2 quartiles. The authors noted that the endotoxin levels in the samples were higher than in similar data from Europe. Subanalysis showed no significant adjusted ORs for children, indicating that adults were responsible for the endotoxin effects found. Allergic subjects had no increase in asthma symptoms compared with nonallergic subjects with higher endotoxin exposure. CONCLUSIONS. In a broad sample of US housing, a significant correlation between household endotoxin and asthma outcomes was demonstrated, driven largely by adults. No protective effect of endotoxin exposure was seen. Current endotoxin exposure had little impact on allergy status. Instead, household endotoxin exposure seemed to be a significant risk factor for increased asthma prevalence. REVIEWER COMMENTS. These data from the National Survey of Lead and Allergens in Housing demonstrate a positive correlation between asthma symptoms in occupants and increasing endotoxin exposure. The implications and sources of higher endotoxin exposures in the United States, noted by the authors, must be considered in this and other studies. Because this study was cross-sectional rather than longitudinal, it could not assess the impact of early endotoxin exposure on the development of asthma and atopy. Thus, the study suggests that endotoxin is a risk factor for asthma and wheezing, but it neither supports nor contradicts the hygiene hypothesis of the development of atopy.

Endotoxin contamination in the dental surgery

Dental waterlines contain large numbers of Gram-negative bacteria. Endotoxin, a component of such organisms, has significant health implications. Paired samples of dental unit water and the aerosols generated during dental procedures were collected, and assayed for bacteria and endotoxin levels, using heterotrophic plate counts and the Limulus amoebocyte lysate test. Consistent with published studies, the extent of bacterial contamination in the dental waters sampled for this investigation surpassed the levels associated with potable water, with counts in excess of 2.0x10(6) c.f.u. ml(-1) in some samples. Correspondingly high concentrations of endotoxin [up to 15 000 endotoxin units (EU) ml(-1)] were present in the water. A statistically significant Spearman correlation coefficient of rho=0.94 between endotoxin (EU ml(-1)) and bacterial load (c.f.u. ml(-1)) was demonstrated. All of the aerosol samples contained detectable endotoxin. Further studies of the consequences of dental endotoxin exposure, and evaluation of means to prevent exposure, are warranted.

Advances in environmental and occupational disorders 2006

In 2006, there continued to be significant contributions to the Journal in the area of environmental and occupational allergy. In addition to very strong clinical observations, there were a number of studies that examined the effect of environmental agents on cellular and molecular processes in allergy, and molecular approaches were also used in investigations of allergen structure and biology. The Journal also received a number of very strong epidemiologic studies examining several aspects of environmental and occupational allergy. Thus, this particular area of our specialty thrives as a result of clinical, mechanistic, epidemiologic, and translational observations. This article reviews a number of these papers presented in the Journal in 2006.

Endotoxemia, Immune Response to Periodontal Pathogens, and Systemic Inflammation Associate With Incident Cardiovascular Disease Events

In periodontitis, overgrowth of gram-negative bacteria may cause endotoxemia and systemic inflammation leading to cardiovascular diseases (CVD). We investigated in a prospective study the associations of serum endotoxin, antibodies to periodontal pathogens, and inflammation markers with the risk of incident CVD. The FINRISK 1992 cohort of 6051 individuals was followed up for 10 years. We examined 185 incident CVD events and a control cohort of 320 individuals using a prospective case-cohort design. High antibody response to periodontal pathogens independently predicted incident CVD events with hazard ratios (HR, quartile 4 versus quartiles 1 to 3, 95% CI) of 1.87 (1.13 to 3.08). The subjects with a high antibody response and high CRP or interleukin (IL)-6 had multivariate-adjusted HRs of 3.01 (1.27 to 7.09) and 3.11 (1.42 to 6.83) compared with low-responders, respectively. The corresponding HRs for high endotoxin concentration were 1.82 (1.22 to 2.73, alone), 3.92 (1.99 to 7.74, with CRP), 3.54 (1.78 to 7.03, with IL-6), and 2.26 (1.13 to 4.52, with tumor necrosis factor (TNF)-alpha) after adjusting for age and gender. These associations were abolished after adjusting for serum lipids. High endotoxin/HDL ratio, however, had a multivariate-adjusted HR of 1.92 (1.19 to 3.08) for CVD events. Our results suggest that the exposure to periodontal pathogens or endotoxin induces systemic inflammation leading to increased risk for CVD.

Size Distribution of Airborne Mist and Endotoxin-Containing Particles in Metalworking Fluid Environments

The objective of the study was to investigate size-selective concentrations of airborne particles and endotoxin in metalworking fluid (MWF) environments. The experiments were conducted under two conditions: (1) MWF collected in the field was aerosolized with a laboratory-scale simulator (MWF simulator) in the laboratory; and (2) MWFs were aerosolized during routine field operations. All experiments included size-selective measurement of airborne concentrations of particle numbers and endotoxin mass using an electrical low-pressure impactor. During field sampling, the total microbial and endotoxin concentrations in the air were also measured with a BioSampler, and the mass concentration of MWF mists was measured with a photometer. Airborne particle concentrations were highest in the fine particle size ranges in the areas affected by MWFs. Relatively high concentrations of endotoxin were detected at particle size below 0.39 μm, which is smaller than the size of intact bacterial cells. The total microbial and endotoxin analysis revealed high microbial contamination in one sampling site although the total particle mass was not elevated. It was concluded that MWF sites can be contaminated with high concentrations of fine particles, and these fine particles may contain microbial components, such as endotoxin. The results call for the size-selective measurement of particles and endotoxin for more comprehensive exposure assessment in MWF facilities.

Neonatal gut barrier and multiple organ failure: role of endotoxin and proinflammatory cytokines in sepsis and necrotizing enterocolitis

Background/Purpose Failure of the gut barrier and endotoxemia have been implicated in sepsis and multiple organ failure (MOF) syndromes in adults. The contributions of endotoxin (ETX) and proinflammatory cytokines (CKs) to the pathophysiology of disease and the outcomes of infants in the neonatal intensive care unit (NICU) are not clear. We measured ETX and CK concentrations in infants who presented with clinical signs of sepsis and/or necrotizing enterocolitis (NEC) to study their impact on MOF and outcomes. Methods Blood samples from infants with signs of NEC and/or sepsis were collected for culture and determination of complete blood cell counts and concentrations of CKs (interleukin [IL]-1 β, tumor necrosis factor [TNF] α, and IL-6) and ETX at the onset of illness. Infants with signs of sepsis but without those of NEC were classified by blood culture results into a confirmed sepsis group (ie, positive culture) or a control group (ie, negative culture). Endotoxin concentrations were determined by chromogenic Limulus amebocyte lysate assay, and CK levels were quantitated by enzyme-linked immunoassay. Data are expressed as mean ± SD and as odds ratios (ORs) with 95% confidence intervals (CIs). P values lower than .05 were considered to be significant. Results There was no demographic or clinical difference among the NEC (n = 27), sepsis (n = 44), and control (n = 56) groups, except that fewer ( P = .02) infants in the NEC group (11%) had received maternal milk feedings as compared with infants in the sepsis group (23%) and those in the control group (39%). Endotoxin concentrations were higher ( P < .0001) in the NEC group (3.30 ± 2.11) as compared with the sepsis group (0.67 ± .86) and the control group (0.09 ± 0.24). Generalized linear regression analysis using formula feeding, mechanical ventilation, and Gram-negative bacteremia as covariates demonstrated that NEC increased ETX concentrations independently ( r = .80; P < .0001). Endotoxemia correlated with higher concentrations of all 3 CKs ( P < .0001). There was an inverse association between ETX and both platelet count ( r = −0.30; P = .0003) and absolute neutrophil count ( r = −0.29; P = .0009). Infants who died of MOF had higher concentrations of ETX (2.83 ± 3.04 vs 0.67 ± 1.04 EU/mL; P < .0001), IL-1β (509 ± 493 vs 106 ± 223 pg/mL; P < .0001), IL-6 (416 ± 308 vs 99 ± 165 pg/mL; P < .0001), and TNF- α (503 ± 449 vs 126 ± 237 pg/mL; P < .0001) as compared with those without MOF. Eighty-six percent of the infants with MOF died. Multivariate logistic regression analysis demonstrated that higher ETX concentrations (OR = 2.47; 95% CI = 1.39-4.40; P = .002) and lower gestational age (OR = 1.41; 95% CI = 1.12-1.77; P = .003) predicted mortality. Conclusions Neonatal endotoxemia and release of proinflammatory CKs are important contributors to MOF and mortality in the NICU. Endotoxemia was most severe at the onset of illness among the infants with NEC, suggesting that gut barrier failure plays an important role in adverse outcomes in the NICU.

Determinants of house dust endotoxin in three European countries ? the AIRALLERG study

The comparison of endotoxin levels between study populations and countries is limited as a result of differences in sampling, extraction, and storage procedures. The objective of this study is to assess the levels and determinants of endotoxin in mattress and living room floor dust samples from three European countries, namely, Germany, the Netherlands, and Sweden, using a standardized sampling, storage, and analysis protocol. The mattress and living room floor dust was collected from the homes of 1065 German, Dutch, and Swedish (pre-)school children. All the samples were collected in the cool season and analyzed for endotoxin in a central laboratory. The determinants were assessed by a standardized questionnaire. The endotoxin concentrations in mattress and living room floor dust were found to be the highest in German homes and lowest in the Swedish ones. Differences between the geometric means were small (factor 1.1-1.7). Most of the associations between endotoxin concentrations and potential determinants were not statistically significant and heterogeneous across countries. However, keeping pets and having more than four persons living in the home were consistently associated with up to 1.7-fold higher endotoxin concentrations in mattress and floor dust. Furthermore, having carpets or rugs, and opening the windows frequently was associated with up to 3.4-fold and 1.3-fold higher endotoxin concentrations in living room floor dust, respectively. The proportion of variance explained by the questionnaire variables was generally low. In conclusion, the data on housing characteristics did not accurately predict the endotoxin concentrations in house dust, and could only partly explain the differences between countries. The differences between the endotoxin concentrations in German, Dutch, and Swedish homes are small. House dust endotoxin concentrations are associated with a number of housing factors, such as pet-ownership, floor cover, number of persons living in the home, and ventilation. The variability of the endotoxin levels between homes and countries can only be partly explained by these factors.

A Preliminary Study on Gram-Negative Bacteria (GNB) and Their Endotoxins in a Gin House in India

The presence of byssinosis, an occupational disease found among cotton mill workers, has been well documented in different parts of the world. The disease develops due to exposure to environmental cotton dust. Evidence suggests that the causative agent for the disease is gram-negative bacteria (GNB) and their endotoxins present on the cotton fibers. An investigation was carried out in a gin house in western India. Environmental dust samples were collected by vertical elutriator (VE). Airborne dust concentrations were very high in the working environment: 2.11 mg/m3 in ginning and 0.95 mg/m3 in the press department (p < 0.05), which was higher than the threshold limit value collected by VE (0.2 mg/m3), and higher than the permissible exposure limit for respirable dust (0.5 mg/m3 for nontextile industries using cotton). In the office control site, the dust concentration was 0.31 mg/m3. The Occupational Safety and Health Administration's cotton dust standard permissible exposure limit for respirable dust is 0.2 mg/m3 in yarn manufacturing, 0.75 mg/m3 in slashing and weaving, and 0.5 mg/m3 in nontextile industries using cotton. These samples also showed high concentrations of airborne endotoxin (p < 0.001) in ginning and pressing (2.77 and 1.52 μg/m3) compared with the office control site (0.009 μ g/m3 measured by Limulus amoebocyte lysate technique). Total enumeration of airborne GNB was carried out qualitatively by the petri plate exposure method and quantitatively by an Andersen 6-stage viable sampler and VE. GNB were recovered in quite high numbers. Among all the GNB, Enterobacter agglomerans were the dominant bacterial flora. Results indicate that gin workers are occupationally exposed to airborne GNB and endotoxins, and require masks.

Endotoxin exposure, wheezing, and rash in infancy in a New Zealand birth cohort

Wheezing in infancy is common and is associated with small lungs, viral respiratory tract infection, and environmental tobacco smoke exposure. Recently, increased levels of endotoxin in the domestic environment have also been associated with infant wheezing, particularly among infants with a family history of atopic disease. To explore associations between exposure to endotoxin at 3 months of age and reported symptoms of wheezing, rhinitis, itchy scaly rash, and atopy at 15 months in a birth cohort of 881 New Zealand children. Using standardized methods, a 1-m(2) site from the bedroom floors of the 3-month-old infants was sampled and analyzed for endotoxin. Wheezing was significantly associated with higher endotoxin levels (odds ratio [OR], 1.54; 95% CI, 1.03-2.30), particularly among infants with a parental history of allergic disease (OR, 1.67; 95% CI, 1.07-2.60). Higher endotoxin concentrations were also strongly associated with recurrent itchy rashes (OR, 1.87; 95% CI, 1.14-3.05), particularly among infants who were atopic (OR, 4.64; 95% CI, 1.56-13.77) or had a parental history of allergic disease (OR, 2.10; 95% CI, 1.22-3.61). Domestic endotoxin was associated with reported airway and skin symptoms in this large group of New Zealand infants. The role of endotoxin in the development of respiratory and skin disease in infancy deserves further study. Reducing domestic endotoxin exposure might reduce infant wheezing and atopic dermatitis, but the long-term benefits of this remain unclear.

Pyrogenic Reactions and Hemorrhage Associated With Intrinsic Exposure to Endotoxin-Contaminated Intravenous Solutions

An epidemiological investigation was conducted to determine risk factors for adverse reactions among patients in hospitals and the possibility of extrinsic or intrinsic contamination of intravenous solutions. A retrospective cohort study was conducted to identify solutions associated with adverse reactions. Implicated lots were cultured for bacteria, and endotoxin concentrations were measured. Five hospitals in the state of Pernambuco, Brazil, were investigated from February through March 2002. Surgical inpatients or outpatients receiving intravenous solutions during the study period. Of 355 surgical patients or outpatients treated at hospitals, 28 (8%) developed illness within a mean of 2.5 hours after exposure to intravenous solutions implicated in adverse reactions; 5 (17.9%) of the case patients died. Laboratory testing of bottles from the lots of Ringer's lactate solution implicated in deaths demonstrated a high mean endotoxin concentration of 88.3 endotoxin units (EU)/mL (range, 9.7-298.0 EU/mL), compared with the permitted limit in Brazil of <0.5 EU/mL. Testing of metronidazole implicated in adverse reactions at another hospital and produced by the same company that manufactured the lots Ringer's lactate solution also showed high endotoxin concentrations (mean level, 8.3 EU/mL [range, 5.0-58.3 EU/mL]). The outbreak was controlled after a national recall of the implicated brand of intravenous solutions. Case patient status was associated with use of Ringer's lactate solution and metronidazole from large bottles, both of which were produced by the same company. High endotoxin concentrations were demonstrated in unopened bottles of implicated products, which is consistent with intrinsic contamination. The high mortality rate may have been compounded by the fact that clinicians administered additional volumes of contaminated 0.9% isotonic sodium chloride solution in response to hypotension or bleeding to some surgical patients. No additional case patients were identified after a national recall of products, inspection, closure of the implicated company's manufacturing facility, and establishment of random quality-control testing of intravenous solutions.

History and results of the two inter‐laboratory round robin endotoxin assay studies on cotton dust

In the US cotton industry, airborne cotton dust levels are regulated, and other countries are moving to specify safety limits for airborne endotoxins. There is concern about potential respiratory health hazards associated with agricultural and other organic dusts. In laboratories, ranking which samples have high and low levels of endotoxin is usually in good agreement between laboratories. When different laboratories assay identical samples, the levels differ. The objective of this research was to evaluate the intra- and inter-laboratory variability for 13 laboratories measuring endotoxin in cotton dust. Two inter-laboratory round robin endotoxin assay studies were conducted using cotton dust. In the first round robin, each laboratory used their normal in-house assay method and then used a common extraction protocol. In the second round robin, a common extraction protocol and endotoxin assay kit was used. The intra-laboratory results had small variations but inter-laboratory results had very high variations. The inter-laboratory results using a common extraction protocol showed reduced differences. Using the same extraction protocol and endotoxin assay kit, the intra-laboratory variation was small and inter-laboratory variation was reduced but not enough for inter-laboratory agreement. Most of the laboratories were able to discern between the high and low endotoxin concentration dusts. Standardization has reduced the differences in results between laboratories and possibly further standardization may bring closer inter-laboratory agreement.

Endotoxin in inner-city homes: Associations with wheeze and eczema in early childhood

An inverse association between domestic exposure to endotoxin and atopy in childhood has been observed. The relevance of this aspect of the hygiene hypothesis to US inner-city communities that have disproportionately high asthma prevalence has not been determined. To measure endotoxin in the dust from inner-city homes, evaluate associations between endotoxin and housing/lifestyle characteristics, and determine whether endotoxin exposure predicted wheeze, allergic rhinitis, and eczema over the first 3 years of life. As part of an ongoing prospective birth cohort study, children of Dominican and African-American mothers living in New York City underwent repeated questionnaire measures. Dust samples collected from bedroom floors at age 12 or 36 months were assayed for endotoxin. Among the samples collected from 301 participants' homes, the geometric mean endotoxin concentration (95% CI) was 75.9 EU/mg (66-87), and load was 3892 EU/m2 (3351-4522). Lower endotoxin concentrations were associated with wet mop cleaning and certain neighborhoods. Endotoxin concentration correlated weakly with cockroach (Bla g 2: r = 0.22, P < .001) and mouse (mouse urinary protein: r = 0.28; P < .001) allergens in the dust. Children in homes with higher endotoxin concentration were less likely to have eczema at age 1 year (odds ratio, 0.70 [0.53-0.93]) and more likely to wheeze at age 2 years (odds ratio, 1.34 [1.01-1.78]). These associations were stronger among children with a maternal history of asthma. Endotoxin levels in this inner-city community are similar to those in nonfarm homes elsewhere. In this community, domestic endotoxin exposure was inversely associated with eczema at age 1 year, but positively associated with wheeze at age 2 years. Endotoxin exposure in the inner-city community may be related to wheeze in the early life; however, given the inverse association seen with eczema, the long-term development of allergic disease is still in question.

New Generation Ceramic Membranes have the Potential of Removing Endotoxins from Dialysis Water and Dialysate

Poor water properties, use of concentrated bicarbonate, and biofilm growth in pipes and storage tanks often cause dialysis water and dialysate contamination with bacteria and endotoxins. High-flux dialysis with bicarbonate may favor endotoxin transfer from the dialysate into the blood exposing patients to serious short-and long-term side effects. Ultrafiltration across hydrophobic synthetic membranes effectively removes endotoxins from dialysis water by combined filtration and adsorption. However, repeated sterilization worsens the membrane separation properties,and limits their use. Ceramic membranes are generally more resistant to harsh operating conditions than polymeric membranes, and may represent an alternative for endotoxin removal. Previously, we proved that the ceramic membranes commercially available at that time were not retentive enough to ensure production of endotoxin-free dialysis water. In this paper, we investigated the endotoxin removal capacity of new generation commercial ceramic membranes with nominal molecular weight cut-off down to 1,000. In dead-end filtration, all investigated membranes produced water meeting, the European standards, or close to,when challenged with low endotoxin concentrations, but only one membrane type succeeded at high endotoxin concentrations. In cross-flow filtration, none produced water meeting the European standard. Moreover, sterilization and rinsing procedures altered the separation properties of two out of three membrane types.

Polymyxin B???Immobilized Fiber Hemoperfusion in a Patient with Active Ulcerative Colitis

A case involving a 31-year-old woman with active ulcerative colitis is described. She suffered symptoms of infraumbilical abdominal pain, severe diarrhea, and low-grade fever that did not improve with conventional treatment, including antidiarrheal drugs and antibiotics. Ulcerative colitis was diagnosed according to endoscopic and histologic findings. She was treated with prednisolone and sulfasalazine, and her symptoms disappeared after 1 month. Sulfasalazine therapy was continued for 3 months, and the patient's condition remained stable for 4 years. Recently, she was admitted with abdominal pain, severe diarrhea, and melena. She was again treated with prednisolone and intravenous hyperalimentation, but her symptoms did not improve. Colonoscopy showed multiple ulcers with bleeding and polyposis and severe edema in the colon. In addition, she had a high blood endotoxin concentration (38.0 pg/ml; normal < 9.8 pg/ml). She underwent polymyxin B-immobilized fiber (PMX-F) hemoperfusion therapy twice. After 2 weeks, her symptoms resolved completely, colonoscopy showed disappearance of the edema, revascularization of the mucosa, and improvement of the ulcers, and blood endotoxin concentration decreased to 5.0 pg/ml. These results suggest that PMX-F treatment may be beneficial for the management of ulcerative colitis with endotoxemia.

Multiple exposures to swine barn air induce lung inflammation and airway hyper-responsiveness

BackgroundSwine farmers repeatedly exposed to the barn air suffer from respiratory diseases. However the mechanisms of lung dysfunction following repeated exposures to the barn air are still largely unknown. Therefore, we tested a hypothesis in a rat model that multiple interrupted exposures to the barn air will cause chronic lung inflammation and decline in lung function.MethodsRats were exposed either to swine barn (8 hours/day for either one or five or 20 days) or ambient air. After the exposure periods, airway hyper-responsiveness (AHR) to methacholine (Mch) was measured and rats were euthanized to collect bronchoalveolar lavage fluid (BALF), blood and lung tissues. Barn air was sampled to determine endotoxin levels and microbial load.ResultsThe air in the barn used in this study had a very high concentration of endotoxin (15361.75 ± 7712.16 EU/m3). Rats exposed to barn air for one and five days showed increase in AHR compared to the 20-day exposed and controls. Lungs from the exposed groups were inflamed as indicated by recruitment of neutrophils in all three exposed groups and eosinophils and an increase in numbers of airway epithelial goblet cells in 5- and 20-day exposure groups. Rats exposed to the barn air for one day or 20 days had more total leukocytes in the BALF and 20-day exposed rats had more airway epithelial goblet cells compared to the controls and those subjected to 1 and 5 exposures (P < 0.05). Bronchus-associated lymphoid tissue (BALT) in the lungs of rats exposed for 20 days contained germinal centers and mitotic cells suggesting activation. There were no differences in the airway smooth muscle cell volume or septal macrophage recruitment among the groups.ConclusionWe conclude that multiple exposures to endotoxin-containing swine barn air induce AHR, increase in mucus-containing airway epithelial cells and lung inflammation. The data also show that prolonged multiple exposures may also induce adaptation in AHR response in the exposed subjects.