Reduction in Indoor Airborne Endotoxin Concentration by the Use of Air Purifier and Its Relationship with Respiratory Health: A Randomized Crossover Intervention Study

Endotoxins are biological components of particulate matter that cause adverse respiratory system effects. Recently, air purifiers have been widely used; however, their effects on endotoxins are not fully understood. We conducted a randomized crossover intervention study to evaluate the effects of air purifiers on indoor endotoxins and occupants’ respiratory health. Thirty-two healthy subjects were randomly assigned to two groups; each group spent four weeks using either a true or sham (filter removed) air purifier. Subsequently, the subjects spent an additional four weeks using the alternative air purifier. The indoor endotoxins in fine (PM2.5) and coarse (PM10–2.5) particulate matter were continuously collected, and pulmonary function was tested repeatedly during the study period. Household characteristics were assessed using a questionnaire. The geometric mean of the PM2.5 endotoxin concentrations was 0.13 EU/m3, which was significantly lower with true purifiers compared with sham purifiers, after adjusting for household characteristics (0.17 EU/m3). In addition, the PM2.5 endotoxin concentrations were significantly greater in reinforced concrete houses than in wooden houses. The PM10–2.5 endotoxin concentrations were significantly greater in homes with two or more household members, and in those with pets. No association was found between endotoxin concentration and respiratory health among the subjects.

An Investigation of Airborne Bioaerosols and Endotoxins Present in Indoor Traditional Wet Markets before and after Operation in Taiwan: A Case Study

Customers in Taiwan prefer to purchase fresh foods and household supplies at indoor traditional wet markets (TWMs). The health risk to indoor TWM staff exposed to bioaerosols needs to be evaluated, since these workers spend long periods of time in the market for stall preparation, selling, and stall cleaning. This study investigated the bioaerosols present in two indoor TWMs. The results showed that the cleaning process at Market A after operations, involving the use of an agitated waterspout, was able to decrease the concentration of bacterial bioaerosols (BBs) by an average of 64%, while at the same time increasing the concentration of fungal bioaerosols (FBs) by about 2.4 fold. The chemical sanitization process at Market B after operations was able to bring about average decreases of 30.8% in BBs and 19.2% in FBs, but the endotoxin concentration increased. Hotspots were found to be associated with vendors of fresh, live poultry and fresh, raw meat/seafood. Pseudomonas spp. and Clostridiumperfringens, both of which can be pathogenic, were found to be the dominant species present in these markets, making up 35.18% to 48.74% and 9.64% to 11.72% of the bacteria present, respectively. Our results provide fundamental information on the distributions of bioaerosols and endotoxins within indoor TWMs both before and after operation.

INCREASED TRAFFICKING OF MESENTERIC LYMPH-DERIVED γδ T CELLS INTO INTESTINAL MUCOSA IS ASSOCIATED WITH GUT INJURY AFTER INTESTINAL ISCHEMIA-REPERFUSION IN RATS

We sought to investigate the effects of mesenteric lymph-derived γδ T cells trafficking into intestinal mucosa on gut injury after intestinal ischemia-reperfusion (IIR). γδ T cells were separated from mesenteric lymph and then infused into the femoral vein of rats after the γδ T cells were labeled with 51Cr. Migration of γδ T cells in vivo across the intestinal mucosa was determined by γ-counter. Meanwhile, TNF-α activity and endotoxin concentration in mesenteric lymph were detected. The population of γδ T cells of Peyer's patches in the small intestines was analyzed by immunofluorescence double staining methods and flow cytometry. After IIR injury, the mean optical density value (MOD) and population of γδ T cells in Peyer's patches of the gut and migration of 51Cr-γδ T cells across the intestinal mucosa were significantly increased, which had highly positive correlations to degree of intestinal injury, TNF-α levels and endotoxin concentration in mesenteric lymph after reperfusion. The increased population of γδ T cells derived from mesenteric lymph trafficking into the intestinal mucosa might promote the small intestinal injury after IIR.

Effect of the acute heat stress on serum endotoxin concentration and the expression of TLR4 mRNA in liver of Arbor Acres broiler chickens

This study was undertaken to investigate the relationship between gut-derived endotoxin and the Toll-like receptor 4 (TLR4) expression in the liver of broilers under acute heat stress (AHS). For this purpose, 120 Arbor Acres chicks were randomised into two groups: control temperature group (CT group, 22 ± 1°C) and high temperature group (HT group, 38 ± 1°C). The chicks received AHS at Day 28 and their small intestine, liver and blood samples were collected after 2 h, 5 h and 10 h to examine the histopathology, biochemical parameters, endotoxin concentrations and TLR4 expression. The results showed that damaged intestinal villi and severe congestion of the hepatic sinusoids were observed, especially after 10 h of AHS in the HT group. In addition, the levels of alanine transferase, aspartate transaminase, and direct bilirubin, except alkaline phosphataseafter were significantly elevated (P < 0.05) and total bilirubin (P < 0.01) and albumin (P < 0.05) were decreased after 10 h of AHS as compared with the CT group, which are associated with liver function. Moreover, the mRNA expression of TLR4 in the liver was noticeably upregulated (P < 0.05) during AHS with significantly increased in endotoxin concentration (P < 0.01) of broilers. Altogether, these findings suggest that the upregulated expression of TLR4 mRNA was triggered via gut-derived endotoxin in heat stress-induced liver injury.