摘要:

Male rats, 5 and 90 d of age, continuously inhaled 500 ppm CO [40% carboxyhemo‐globin (COHb)l for 5.5–8.0 wk. Cardiomegaly andpolycythemia developed as previously reported. Heart weight gain in young and old rats treated with CO was accompanied by increased cytochrome c content (nmol) in both left ventricle (LV) and right ventricle (RV) relative to controls. Cytochrome c concentration (nmolIg wet weight), however, was significantly depressed in LV and RV of young CO‐exposed rats relative to controls, while there was no change in LV and RV of the old CO‐exposed group. LV cytochrome c concentration was significantly higher than that of RV in both young and old, CO‐exposed and control rats. On the other hand, cytochrome c concentration in young and old control LVs was similar, as was cytochrome c concentration in RVs of young and old control rats. Three additional experiments were carried out with 5‐d‐old rats inhaling 500 ppm CO, for 47 and 25 d. These also showed the increase in myocardial cytochrome c content and compromise of cytochrome c concentration, and both changes were greater with longer exposure.

ISSN:0098-4108    

DOI:10.1080/15287398309530436

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

This study was designed to correlate autopsy findings with the effects on cage behavior, laboratory values, and mercury clearance of long‐term, low‐dose exposure of primates to methylmercury. Six rhesus monkeys were given daily methylmercury hydroxide (MeHg) orally in apple juice on a preplanned dosage schedule. Three were sacrificed while receiving MeHg (group I) and the other 3 were sacrificed 2–5 mo after cessation of MeHg administration (group II). Whole‐blood Hg levels (organic and inorganic) were assayed weekly, and major organ levels were assayed at autopsy. Whole‐blood Hg levels were maintained between 1 and 2 μg/ml when the monkeys were given a MeHg dose of 80–125 μg/kg·d for up to 1 yr. The Hg burden of the major organs appeared to be dose‐ and duration‐related. After periods of clearance (2.5–5 mo), intestinal wall Hg burden decreased to less than 1 μg/g, and the hepatic Hg burden was still between 1.12 and 2.37 μg/g. However, the kidneys had a higher concentration of Hg, ranging from 10.34 to 29.54 μg/g. Whenever there was a high concentration of Hg, significant ultrastructural changes were observed. In the kidneys there were intracytoplasmic vacuoles and electron‐dense inclusion bodies. In the small intestine of the animals cleared of mercury (group II), there were normal Paneth cells, as well as some degenerative cells characterized by dilation of endoplasmic reticulum and the presence of intracellular inclusion bodies. These findings suggest the long turnover time of Hg in these cell populations. During the period of study, weekly routine laboratory data including hematology, blood chemistry, and liver and kidney function tests did not reveal any significant changes.

ISSN:0098-4108    

DOI:10.1080/15287398309530437

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Isolated rabbit pulmonary alveolar macrophages were found to be a convenient biological model system, relevant for studies of the toxicity of air pollutants. The phagocytic capacity and the oxygen consumption were used as test parameters and studied simultaneously on the same cells. The toxicity of extracts of airborne particles (ø < 15 μm) collected in urban and rural areas was investigated and compared to a cigarette‐smoke condensate. An extract of particles from a car tunnel was found to be the most toxic air sample, inhibiting phagocytosis as well as respiration of the macrophages at a concentration representing 5 m3air/ml cell suspension. A corresponding sample collected on a roof of a five‐storied building in the central area of a city (population 600,000} was found to inhibit phagocytosis but did not affect respiration. Further investigations revealed that one effect of the “tunnel” extract could be explained as an uncoupling of the mitochondria! respiratory control. Compared to the cigarette‐smoke condensate, the toxicity of the air samples was infinitesimal.

ISSN:0098-4108    

DOI:10.1080/15287398309530438

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The effects of exposures to sulfur dioxide and formaldehyde atmospheres on the clearance of inhaled, insoluble tracer particles from the lungs of rats have been studied. The tracer particles employed were polystyrene latex microspheres radio‐labeled with51Cr. Following the deposition of the 1.9‐μm activity median aerodynamic diameter (AMAD) particles, the rats were divided into 3 groups for a single 4‐h exposure to purified air, 20 ppm sulfur dioxide, or 20 ppm formaldehyde. Early, presumably upper‐respiratory‐tract, clearance was monitored by analysis of radioactivity excreted in feces, while late, presumably deep‐lung, clearance was followed by thoracic counting of the animals. Both the sulfur dioxide and formaldehyde atmospheres did significantly delay early clearance (p < 0.1, two‐tailed t‐test). However, the late clearance rates of the two pollutant‐exposed groups of rats were not significantly different from that of the purified air‐exposed group of rats. Although sulfur dioxide had numerically greater effects than formaldehyde, the differences were not statistically significant at the p < 0. 7 level.

ISSN:0098-4108    

DOI:10.1080/15287398309530439

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Rabbits were exposed to submicrometer sulfuric acid mist (H2SO4) for 1 h/Id, 5 d/w for 4 wk, during which time mucociliary clearance was monitored by external in vivo measurements of tagged tracer aerosol retention. One group was exposed orally to 250 μg/m3, another to the same concentration via the nose, and a third to 500 μg/m3also via nasal breathing. Clearance was accelerated on specific individual days during the course of the acid exposures, especially at 500 μg/m3. In all series, clearance was significantly faster, compared to preexposure controls, during a 2‐wk follow‐up period after acid exposures had ceased. At the end of this period, the rabbits were sacrificed, and histological sections were obtained from the tracheobronchial tree. Significantly increased epithelial thickness of small conducting airways, compared to sham exposure controls, occurred in rabbits exposed orally at 250 μg/m3or nasally at 500 μg/m3, and additionally the lumen of the smallest airways of the former group was narrower than control. The number of airways containing epithelial secretory cells was also significantly greater in these acid exposure groups compared to sham controls. The only change in the rabbits exposed nasally at 250 μg/m3was a significant increase in the number of airways with epithelial secretory cells in the smallest airway classification. The histological alterations provide a basis for observed changes in clearance, and are similar to those found in chronic bronchitis in humans and experimental animals. Differences in site and degree of histological response and degree of physiological change between the two groups exposed to identical acid concentrations appear to have been due to differences in exposure mode, with resultant effects on breathing pattern, aerosol size distribution, and concentration penetrating beyond the upper respiratory tract to specific lung sites.

ISSN:0098-4108    

DOI:10.1080/15287398309530440

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The kinetics of chloride were studied in Sprague‐Dawley rats following the oral administration of Na36CI. The half‐life for36Cl−absorption from plasma was 19.2 h corresponding to a rate constant of 0.0361 h−1, while the half‐life for36Cl−elimination from plasma was 51.9 h, corresponding to a rate constant of 0.0134 h−1. At 120 h, radioactivity was highest in plasma, followed by kidney, lung, stomach, and spleen, and the lowest activity was observed in fat. Plasma and packed cells contained almost the same concentration of36Cl−. Plasma protein binding of chloride was significantly higher than liver protein binding. Subcellular distribution in liver fractions revealed that most of the36Cl−was located in the cytosolic fraction. The excretion of chloride occurred primarily by the kidney.

ISSN:0098-4108    

DOI:10.1080/15287398309530441

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

TREATMENT, RECOVERY, AND DISPOSAL PROCESSES FOR RADIOACTIVE WASTES: RecentAdvances Edited by J. I. Duffy, Noyes Data Corporation, Park Ridge, New Jersey, 1983, 287 pp., $39.00

ISSN:0098-4108    

DOI:10.1080/15287398309530442

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0098-4108    

DOI:10.1080/15287398309530415

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor