摘要:

The responses of guinea pigs and rats to inhaled sulfuric acid aerosols were compared to define species differences and to determine the small‐animal model most relevant to human exposures. Rats were exposed for 6 h to 1, 10, and 100 mg H2SO4/m3. Guinea pigs were exposed for 6 h to 7, 10, and 27 mg H2SO4/m3. Tracheal mucous clearance of guinea pigs was slowed 7 d after exposures to 1 mg H2SO4/m3. A tendency toward faster clearance was observed at high concentrations of H2SO4for both guinea pigs and rats (statistically significant only for the rats). The speeding of mucous clearance was correlated with increases in airway sialic acid and also with the appearance of excess tracheal secretions, detected using scanning electron microscopy in both rats and guinea pigs. The responses of guinea pigs to sulfuric acid exposures were more similar to those reported for humans than were those of rats.

ISSN:0098-4108    

DOI:10.1080/15287398609530808

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Male Fischer‐344 rats (control, C = 12; experimental, E = 11) were subjected to pulmonary‐function testing procedures. The experimental group was then exposed to 0.7 ppm ozone for 28 d, 20 h/d, and both groups were tested at the termination of the exposure and after 4 and 9 wk of recovery in clean filtered air. Another group of animals (C = 6, E = 12) was similarly treated, but at each test point one‐third were sacrificed for microscopic evaluation. When percent changes from preexposure values were compared to controls at each time point, the ozone exposure produced obstructive changes in the lung, including significant decreases (p < 0.05) in forced expiratory flows (MEF2540.3%, MEF1070.7%), lung volumes (IC 22.5%, FVC 21.8%), and DLCO(20.7%) and a significant increase in functional residual capacity (FRC 61.1%). The total lung capacity (IC + FRC) was not significantly changed by the ozone. Microscopic examination revealed characteristic lesions in the region of terminal bronchioles and central acinar alveoli marked by peribronchiolar edema, bron‐chiolization of alveolar duct epithelium, and type II cell proliferation in involved alveoli with increased numbers of macrophages and a few leucocytes. Clearly discernable was a focal interalveolar‐alveolar duct reaction made up of fibroblasts, a few inflammatory cells, and conspicuous mast cells, all embedded in a loose meta‐chromatic matrix. After 4 wk of recovery, all measurements of lung volume and DLCOhad returned to the values of the control group; however, even after 9 wk some of the measurements of lung flow (MEF25, MEF10) remained significantly although less depressed (27.9 and 40.1%, respectively). Histologically, after 4 wk recovery, there remained only a slight unevenly distributed inflammatory reaction. In these foci there was often a residual, narrower, more condensed band of eosinophilic material, presumably collagen, that sometimes contained interspersed mast cells. After 9 wk, this collagen accumulation within the thickened wall of the alveolar duct could occasionally still be noted. These data suggest that the florid response seen at the end of exposure was related to the obstructive changes measured and that, with recovery, the residual central acinar‐alveolar duct thickening may be responsible for the persistently diminished air flows.

ISSN:0098-4108    

DOI:10.1080/15287398609530809

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

REPRODUCTIVE TOXICOLOGY. Edited byRobert L. Dixon, Raven Press, New York, 1985, 350 pp., $69.50.

ISSN:0098-4108    

DOI:10.1080/15287398609530810

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0098-4108    

DOI:10.1080/15287398609530797

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor