Industrial hygienists (IHs) are called upon to investigate exposures to mold in indoor environments, both residential and commercial. Because exposure standards for molds or mycotoxins do not exist, it is important for the industrial hygienist to have a broad knowledge of the potential for exposure and health effects associated with mold in the indoor environment. This review focuses on the toxic effects of molds associated with the production of mycotoxins, and the putative association between health effects due to mycotoxin exposure in the indoor environment. This article contains background information on molds and mycotoxins, and a brief summary and review of animal exposure studies, case reports, and epidemiological studies from the primary literature concerning inhalation of mycotoxins or potentially toxin-producing molds. The relevance of the findings in the reviewed articles to exposures to mold in indoor, non-agricultural environments is discussed. Although evidence was found of a relationship between high levels of inhalation exposure or direct contact to mycotoxin-containing molds or mycotoxins, and demonstrable effects in animals and health effects in humans, the current literature does not provide compelling evidence that exposure at levels expected in most mold-contaminated indoor environments is likely to result in measurable health effects. Even though there is general agreement that active mold growth in indoor environments is unsanitary and must be corrected, the point at which mold contamination becomes a threat to health is unknown. Research and systematic field investigation are needed to provide an understanding of the health implications of mycotoxin exposures in indoor environments.
A B S T R A C T Sodium-potassium-activated adenosine triphosphatase (Na-K-ATPase) is associated with electrolyte transport in many tissues. To help delineate its role in intestinal transport, changes in rat intestinal electrolyte and water transport induced by injecting methylprednisolone acetate 3 mg/100 g or deoxycorticosterone acetate (DOCA) 0.5 mg/100 g per day for 3 days were correlated with changes in Na-K-ATPase activity. Methylprednisolone increased sodium and water absorption, potassium secretion, transmural potential difference, and Na-K-ATPase activity in the jejunum, ileum, and colon. Examination of isolated epithelial cells demonstrated that the jejunal and ileal increase in Na-K-ATPase occurred in both the villus tip and crypt areas. The time-courses of the ileal enzyme and transport changes were identical. Permeability, Mg-ATPase, and adenylate cyclase activities were unchanged by methylprednisolone. DOCA increased sodium and water absorption, potassium secretion, transmural potential difference, and Na-K-ATPase activity in the colon alone. Colonic Mg-ATPase and adenylate cyclase activities were unaffected. Jejunal and ileal enzyme activity, electrolyte transport, and permeability were unchanged by DOCA. Methylprednisolone and DOCA were not additive in their effect on colonic Na-K-ATPase activity. Methylprednisolone and DOCA increased electrolyte and water transport and Na-K-ATPase activity concomitantly in specific segments of small intestine and colon. These data are consistent with an important role for Na-K-ATPase in intestinal electrolyte and water transport.
There is no uniformity in the suggested guidelines for acceptable levels of fungi in indoor ambient air. Thus, health professionals have no way to determine what levels of fungi may pose a threat to human health. The authors reviewed the published literature to identify data reported for noncomplaint structures, that is, structures in which occupants did not have health concerns associated with the quality of the indoor air. For both commercial and residential structures, fungal concentrations detected were often higher than currently suggested guidance values. The average indoor air concentration in 149 noncomplaint commercial buildings was 233 colony forming units (CFU) per cubic meter, whereas outdoor ambient air levels averaged 983 CFU/m(3). Total indoor spore counts ranged from 610 to 1040 spores/m(3) in three commercial buildings. Outdoor total spore counts associated with these buildings ranged from 400 to 80,000 spores/m(3). The average indoor concentration reported for 820 noncomplaint residential structures was 1252 CFU/m(3) with an average outdoor level of 1524 CFU/m(3). Total spore counts detected indoors at 85 residential structures ranged from 68 to 2307 spores/m(3). Outdoor spore levels associated with these structures ranged from 400 to 80,000 spores/m(3). A large proportion of both commercial and residential noncomplaint structures have indoor ambient air fungal concentrations above 500 CFU/m(3), a level often advocated as requiring remediation in structures when occupants complain of nonspecific adverse health symptoms.
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