摘要:

To determine the extent of neurotoxicity of parenterally administered hexacarbons, male Sprague‐Dawley rats were given eithern‐hexane or 2,5‐hexanedione for 35 consecutive days. Electrophysiologic measurements showed a lengthening of the sciatic and sural nerve action potentials (slower conduction velocities) and increased refractory periods. These effects correlated with a shift in the nerve membrane sensitivity to potassium‐induced depolarization. A similar effect can be induced by ouabain, an Na+, K+A TPase inhibitor. These effects were seen with bothn‐hexane and 2,5‐hexanedione. Although the treated animals gained wieght more slowly than controls, they showed no loss of motor function when tested behaviorally, and there were no signs of histopathology in the peripheral nerves. These results show that hexacarbons produce a neurotoxocity that can be demonstrated by changes in nerve excitability, prior to overt behavioral neurotoxocity. Furthermore, these electrophysiologic changes may be related to a hexacarbon‐induced disruption of nerve‐membrane A TPase activity.

ISSN:0098-4108    

DOI:10.1080/15287398409530544

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Airborne metallic particulates are associated with fossil‐fueled power plants, automobile exhausts, metal mining, and metallurgical smelters. Therefore, the possible toxic effects of metals on the lung are of environmental and occupational concern. In this investigation we determined the effects ofin vitroexposure to metallic ions on the following parameters: oxygen consumption and membrane integrity of alveolar macrophages and type II cells, and chemiluminescence of zymosan‐stimulated alveolar macrophages. Cu2+and Zn2+exhibited marked toxicity to isolated alveolar macrophages and type II cells, while V3+exhibited intermediate toxicity. In contrast, short‐termin vitroexposure to As5+and Se4+had little effect on alveolar macrophages and type II cells. Although the data suggest that exposure to certain metals may be harmful to the lung, the various pulmonary parameters tested in this investigation display differing susceptibility to metal exposure. That is, metals are less toxic to alveolar type II cells than to alveolar macrophages. Our data also indicate that chemiluminescence is the most sensitive assay for monitoring the viability of alveolar macrophages, while oxygen consumption is a sensitive assay for type II cells.

ISSN:0098-4108    

DOI:10.1080/15287398409530545

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Trachea from albino mice were cut transversely into nearly identical rings and incubated in medium 199 with Hanks salts and HEPES buffer at 37°C. Sodium selenite at 0.5–5 mMdepressed the ciliary activity. With 1 and 5 mMsodium selenite, a 50% reduction in the activity index was observed after approximately 5 and 1.5 h, respectively. The ATP content in trachea rings was reduced with 0.05–5 mMsodium selenite, and increasing concentrations gave decreasing amount of ATP after incubation for 4 and 21 h. The rate of protein synthesis as determined by incorporation of radioactive leucine was reduced with 0.5 and 2 mMsodium selenite. The synthesis was reduced quickly by 2 mMsodium selenite, which gave a 30% reduction after incubation for 1 h.

ISSN:0098-4108    

DOI:10.1080/15287398409530546

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A bovine kidney cell culture system was used to assess what relationship mercuric chloride (HgCl2) uptake and subcellular distribution had to cytotoxicity. Twenty‐four‐hour incubations with 0.05–50 μMHgCl2elicited a concentration‐related cytotoxicity. Cellular accumulation of203Hg was also concentration‐related, with 1.0 nmol/106cells at the IC50. Measurement of Hg uptake over the 24‐h exposure period revealed a multiphasic process. Peak accumulation was attained by 1 h and was followed by extrusion and plateauing of intracellular Hg levels. Least‐squares regression analysis of the cytotoxicity and cellular uptake data indicated a potential relationship between the Hg uptake and cytotoxicity (r = 0.91). However, the subcellular distribution of Hg was not concentration‐related. Mitochondria and soluble protein fractions accounted for greater than 65% of the cell‐associated Hg at all concentrations. The remaining Hg was distributed between the microsomal (6–10%) and nuclear and cell debris (11–22%) fractions at all concentrations tested. Less than 20% of the total cell‐associated Hg was bound with metallothionein‐like protein.

ISSN:0098-4108    

DOI:10.1080/15287398409530547

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

On d 7 or 12 of gestation or on d 2 postpartum, Swiss ICR dams were administered either (1) a single intragastrk dose of Pt(SO4) at the LD1 level or dilute H2O4at an equivalent volume, pH, and sulfate content, or (2) a single subcutaneous dose of Na, PtCl6or phosphate‐buffered saline at an equivalent volume and pH. To differentiate prenatal from postnatal effects of the compounds on the offspring, a full cross‐fostering design was employed. Rate of growth (as a function of weight gain) and gross activity of the neonates were assessed on d 8 or 13 postpartum. On d 60–65 postpartum, open‐field behavior (ambulations and rearings), rotarod performance, and passive avoidance learning of the adult offspring were investigated. Exposure to Pt(SO4)2resulted in reduced offspring weight from d 8 to 45 postpartum, whereas the major effect of Na2PtCl6was a reduction in activity level of the offspring of mothers exposed on d 12 of gestation.

ISSN:0098-4108    

DOI:10.1080/15287398409530548

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Rats were chronically infected withPseudomonas aeruginosaby entrapping viable bacteria in agar beads and intratracheally inoculating the beads into the left lung. The infection was allowed to stabilize over a 10‐d period and the animals were then placed in environmental chambers and exposed to either filtered air or 0.64 ppm ozone (23 h/d) for 14 or 28 d. Rats exposed to ozone had reduced body weight and increased lung sizes and lung weights when compared with animals breathing filtered air. Rats inoculated with beads containing liveP. aeruginosahad increased lung weights when compared with rats inoculated with beads containing heat‐killedP. aeruginosaor controls. Quantitation of total viable bacteria in rats exposed to ozone or to filtered air revealed no significant differences in bacterial numbers. Thus, in this model, chronic exposure to ozone produces increases in lung volume and weight but does not enhance a smolderingPseudomonasinfection.

ISSN:0098-4108    

DOI:10.1080/15287398409530549

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

To examine the role of the vagal pathway on the cardiopulmonary functions in NO2‐exposed rats, phenyl diguanide, which stimulates type J receptors in the lungs, was injected to control and exposed rats at a constant dose. Based on a statistical test, a decrease in the heart rate (HR) after the injection was observed in the groups exposed to 20 ppm NO2for 1.5 h and 3 h, and 10 ppm for 24 h. On the other hand, an increase in respiratory rate (RR) was observed in the groups exposed to 10 ppm for 3 h and 4 ppm for 1 wk. No change in HR and RR was found in the group exposed to 0.4 ppm for 4 wk. These results suggest that the augmentation of the reflex cardiopulmonary responses due to stimulation to the type J receptors was produced by exposures with a higher concentration of NO2

ISSN:0098-4108    

DOI:10.1080/15287398409530550

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Rats were exposed to three concentrations of diluted diesel exhaust for 6 mo and 1 yr. Bronchopulmonary lavage was used to obtain the pulmonary phagocytes from the animals in order to study the response of the phagocytic defenses to the inhaled particulate. The cell numbers and volumes were measured using an electronic particle counter. The cell counts of alveolar macrophages (AM) were proportional to the concentration of diesel exhaust particulate (DP) in the chronic exposures. AM increased in the lungs in response to the rate of DP mass entering the lungs, rather than to the total DP burden in the lung. The geometric mean volumes of AM from the exposed and control animals were approximately 1100 pm3at both 6 and 12 mo of exposure, although exposed cell‐volume distributions skewed towards larger sizes. The AM volume distributions extended to 2000 μm3in both control and 250 μg DP/m3exposed animals and up to 5000 μm3in cells from animals exposed to 750 and 1500 μg DP/m3. The volume distributions were found to be reproducible in equivalent control and exposed cell populations. Polymorphonuclear leukocytes were present in the lavaged cell populations from the animals exposed to 750 and 1500 μg/m3. In addition, at 1 yr of exposure, lymphocytes were also lavaged from animals exposed to 750 and 1500 μg DP/m3. Protein, β‐glucuronidase activity, and acid phosphatase activity were measured in the lavaged cells, and were elevated in the cells from animals exposed to 750 and 1500 μg/m3. The buoyant density of diesel‐laden AM was found to be greater than that of control AM, and overlapped with the buoyant density of the polymorphonuclear leukocytes.

ISSN:0098-4108    

DOI:10.1080/15287398409530551

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

This study was done to produce a model of chronic bronchitis. Twelve beagle dogs were exposed to 500 ppm sulfur dioxide (SO2) for 2 h/d, 5 d/wk for 21 wk and 4 dogs were sham‐exposed to filtered ambient air for the same period. Exposure effects were evaluated by periodically examining the dogs using chest radiographs, pulmonary function, tracheal mucous clearance, and the cellular and soluble components of bronchopulmonary lavage fluids. Dogs were serially sacrificed after 13 and 21 wk of exposure and after 6 and 14 wk of recovery. Clinical signs produced in the SO2‐exposed dogs included mucoid nasal discharge, productive cough, moist rales on auscultation, tonsilitis, and conjunctivitis. Chest radiographs revealed mild peribronchiolar thickening. Histopathology, tracheal mucous clearance measurements, and lavage cytology were consistent with a diagnosis of chronic bronchitis. It is concluded that repeated exposure to 500 ppm SO2for 21 wk produced chronic bronchitis in the beagle dog. Complete recovery occurred within 5 wk following cessation of SO2exposure.

ISSN:0098-4108    

DOI:10.1080/15287398409530552

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The toxicity of dl‐2‐ethylhexyl phthalate (DEHP), a ubiquitous environmental pollutant, was measured experimentally as a contaminant in shrimp aquaculture feeds. Diets containing 40 to 50,000 ppm DEHP were fed toPenaeus vannameifor 14 d at 4% body weight/d. DEHP concentrations in shrimp, diet, and water were measured by electron‐capture gas chromatography. Whole‐body residues in shrimp were 18 ppm at the highest dose, and bioconcentration factors were inversely proportional to dose. DEHP in water was ≤ 1.7 ppb for all dose levels. No increased mortality or histopathological alterations were observed at any dose.

ISSN:0098-4108    

DOI:10.1080/15287398409530553

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor