Journal of environmental pathology and toxicology最新文献

The percutaneous penetration of three insect repellents was determined in hairless dogs. Each compound was administered intravenously and topically to three dogs. Urine, feces and blood samples were assayed for radioactivity by scintillation counting. The percent penetration for N,N-diethyl-m-toluamide (m-deet, the most widely used insect repellent), its isomer N,N-diethyl-p-toluamide and 2-ethyl-1,3-hexanediol were 7.9%, 7.6%, and 10.3% respectively. The results for m-deet penetration in the hairless dog are comparable to those in man.

Syrian golden hamsters were exposed to the smoke from a number of experimental cigarettes which contained differing amounts of nicotine and carbon monoxide. Pulmonary hemorrhages were induced, the number of which were clearly dependent on the nicotine content of the cigarette smoke. Electron microscopy revealed cytoplasmic swelling and ruptured cell membranes in alveolar type 1 cells and endothelial cells.

Selected oviductal lesions associated with the continuous feeding of diethylstilbestrol (DES) were examined ultrastructurally Virgin female mice were fed diets containing 0, 320 and 640 ppb DES from 4 weeks of age. All animals reported on in this study were removed from the study and sacrificed for histopathological and electron microscopy examination when moribund and ranged from 622 to 762 days on the experiment. One oviductal change consisted of markedly vacuolated ciliated epithelial cells located primarily in the fimbria. Electron microscopy revealed that the large vacuoles were present throughout the cytoplasm of affected cells. These vacuoles were not lipid and appeared to be fluid-filled. No significant alterations in number or structure of cilia were observed. Since this alteration was seen in both DES and control animals, it may be age-related. A second kind of oviductal lesion consisted by enlarged secretory cells located predominantly in the isthmus. The cytoplasm of these cells consisted of extremely enlarged, dilated rough endoplasmic cisternae forming a subnuclear mass. Numerous primary and secondary lysosomes were seen in the apical cytoplasm between the cell membrane and nucleus. No evidence of a Golgi complex was seen. These alterations were seen only in DES-exposed animals and seem to indicate continued protein synthesis by the secretory cells but a deficiency in the packaging of this protein into secretory granules.

Syrian hamster embryo cells were treated with galactose oxidase (EC 1.1.3.9) followed by reduction with tritiated sodium borohydride (NaB3H4) at pH 7.4. Labeling patterns of galactose and galactosamine in glycolipids and glycoproteins were determined by thin-layer chromatography and SDS-gel electrophoresis respectively. After 20 hours of interaction between the chrysotile asbestos and Syrian hamster cell cultures, a decrease in surface labeling of both glycolipids and glycoproteins was observed. Tritiated disialoganglioside (GDla) and the higher molecular weight labeled glycoproteins were significantly reduced by asbestos interaction.

A study was designed to test the effect of animal source ammonia on some component concentrations in test atmospheres produced to measure the health effects of pollutants in the exhaust emissions of gasoline-powered engines equipped with oxidative catalyst converters. The dominantly acidic nature of the exhaust particulate phase required an evaluation of test chamber concentrations of the alkaline components contributed by the test animals. The animal population in the chamber was critical in maintaining the essential integrity of the pollutant atmosphere. Measures to minimize the production of the animal-produced interferent(s) were helpful in attenuating the interfering effect.

Radiolabelled 2,2',4,4',5,5'-hexabromobiphenyl was metabolized in vitro by rat liver microsomal enzymes to give more polar ether soluble lipophilic metabolites, trichloroacetic acid soluble conjugates and a macromolecular adduct fraction. The rates of formation of the three metabolic fractions were significantly enhanced using Firemaster BP-6 and 2,2',4,4',5,5'-hexabromobiphenyl induced microsomal enzymes. Comparative metabolic studies with the 4-brombiphenyl substrate showed that the lower brominated biphenyl substrate was more readily metabolized and the rate of metabolism was enhanced only with the Firemaster BP-6 induced microsomal enzymes and not the 2,2', 4,4',5,5'-hexabromobiphenyl induced enzyme system.

Mice were exposed to various dosages of lead, cadmium, or methylmercury for 10 weeks. At the end of the feeding trial, splenic lymphocytes were evaluated for responsiveness in mixed lymphocyte cultures. Cadmium and methylmercury as well as one dose level of lead tended (not significant) to stimulate the lymphocyte reaction. These results are discussed and compared to other investigations concerned with the effect these environmental contaminants have on the cell mediated immune response of animals.

Fertility was examined in 199 women exposed to internal and external radiation while employed in the radium watch-dial painting industry in Illinois between 1916 and 1929. In women with at least one live birth, mean log live-birth rate was significantly lower in the highest (estimated) ovarian-dose group (i.e., greater than or equal to 20 rem) than in the lowest group (< 5 rem). In multiple regression analysis, intake dose (proportional to alpha-particle dose to ovaries) but not duration of employment (relevant to external gamma-ray dose to ovaries) was a statistically significant predictor of log live-birth rate. There was no evidence for an increase in fetal deaths with increasing ovarian dose level (rem). This suggests that the findings on live-birth rate may not involve post-implantation dominant lethal mutations, but preimplantation losses could not be evaluated. Some possible explanations for these findings are discussed.