Formaldehyde, acetaldehyde, and acrolein are well-known upper respiratory tract irritants and occur simultaneously as pollutants in many indoor and outdoor environments. The upper respiratory tract, ...and especially the nose, is the prime target for inhaled aldehydes. To study possible additive or interactive effects on the nasal epithelium we carried out 1- and 3-day inhalation studies (6 hr/day) with formaldehyde (1.0, 3.2, and 6.4 ppm), acetaldehyde (750 and 1500 ppm), acrolein (0.25, 0.67, and 1.40 ppm), or mixtures of these aldehydes, using male Wistar rats and exposure concentrations varying from clearly nontoxic to toxic. The (mixtures of) aldehydes were studied for histopathological and biochemical changes in the respiratory and olfactory epithelium of the nose. In addition, cell proliferation was determined by incorporation of bromodeoxyuridine and proliferating cell nuclear antigen expression. Effects were primarily observed after 3 days of exposure. Histopathological changes and cell proliferation of the nasal epithelium induced by mixtures of the three aldehydes appeared to be more severe and more extensive in both the respiratory and the olfactory part of the nose than those observed after exposure to the individual aldehydes at comparable exposure levels. As far as nasal histopathological changes and cell proliferation are concerned neither dose addition nor potentiating interactions occurred at no-toxic-effect levels, except for a possible potentiating effect of acetaldehyde at noneffect levels. The results did not indicate a major role for aldehyde dehydrogenases in the biotransformation of the aldehydes studied. Activities of glutathione S-transferase and glutathione reductase after 3 days of exposure to acrolein, alone or in combination with formaldehyde and acetaldehyde, were depressed whereas the glutathione peroxidase activity was elevated. No decrease of nonprotein sulphydryl levels were observed. These findings suggest that, for no-toxic-effect levels, combined exposure to these aldehydes with the same target organ (nose) and exerting the same type of adverse effect (nasal cytotoxicity), but partly with different target sites (different regions of the nasal mucosa), is not associated with a greater hazard than that associated with exposure to the individual chemicals.
This paper aimed to clarify whether maternal inhalation of engineered nanoparticles (NP) may constitute a hazard to pregnancy and fetal development, primarily based on experimental animal studies of ...NP and air pollution particles. Overall, it is plausible that NP may translocate from the respiratory tract to the placenta and fetus, but also that adverse effects may occur secondarily to maternal inflammatory responses. The limited database describes several organ systems in the offspring to be potentially sensitive to maternal inhalation of particles, but large uncertainties exist about the implications for embryo-fetal development and health later in life. Clearly, the potential for hazard remains to be characterized. Considering the increased production and application of nanomaterials and related consumer products a testing strategy for NP should be established. Due to large gaps in data, significant amounts of groundwork are warranted for a testing strategy to be established on a sound scientific basis.
This paper aimed to clarify whether maternal inhalation of engineered nanoparticles (NP) may constitute a hazard to pregnancy and fetal development, primarily based on experimental animal studies of ...NP and air pollution particles. Overall, it is plausible that NP may translocate from the respiratory tract to the placenta and fetus, but also that adverse effects may occur secondarily to maternal inflammatory responses. The limited database describes several organ systems in the offspring to be potentially sensitive to maternal inhalation of particles, but large uncertainties exist about the implications for embryo-fetal development and health later in life. Clearly, the potential for hazard remains to be characterized. Considering the increased production and application of nanomaterials and related consumer products a testing strategy for NP should be established. Due to large gaps in data, significant amounts of groundwork are warranted for a testing strategy to be established on a sound scientific basis.
An informal one-and-a-half-day workshop devoted to research needs on the health effects of airborne particulate matter (PM) was held in Park City, Utah, on April 29 and 30, 1996, in conjunction with ...the Second Colloquium on Particulate Air Pollution and Health at Park City, Utah, on May 1-3, 1996. The objective of the workshop was to prepare a holistic assessment of knowledge gaps and research opportunities for presentation at the penultimate session of the colloquium. The workshop reviewed the research progress made since the first PM colloquium (Irvine, California, January 1994) and the findings of recent major reviews of the PM literature by the World Health Organization-European Region, the U.K. Health Department, the National Institute of Public Health in the Netherlands, and the U.S. Environmental Protection Agency. It then discussed: (1) the nature of ambient PM; (2) population segments at special risk; (3) the nature of the health effects of concern; (4) the sources of ambient air PM; and (5) the implications of ambient air PM health effects on occupational exposure limits and occupational cohorts. The workshop concluded that:
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