摘要:

The development and operation of a high‐voltage direct‐current (HVDC) transmission line in rural Minnesota generated public concern over potential adverse effects to nearby residents and their livestock. Electrical environmental parameters near an HVDC line decline rapidly with distance, but effects on ambient space charge have been detected out to 1 mile. Previous studies of powerline effects on livestock have involved the more common alternating‐current (HVAC) lines, which create a different electrical environment. To identify potential adverse effects of HVDC line operation on livestock, case‐control and cohort study methods were used to examine various indices of Holstein performance in relation to distance from the line and the onset of line operation. It was believed that these indices would reflect changes in physiologic function or overt health effects that might arise from the HVDC environment. High‐quality performance data from existing Dairy Herd Improvement Association (DHIA) records were obtained for 97% of qualifying herds located within 10 miles of the line. The large number of animals and years of observation provided high statistical power to detect even small systematic changes in performance. No significant differences in milk production or reproductive capacity were associated with presumed exposure to the HVDC environment. The absence of measurable effects in a large “sentinel” animal population may have implications for the assessment of human health risks related to HVDC transmission lines.

ISSN:0098-4108    

DOI:10.1080/15287398609530930

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Extracts from blue‐green algal blooms (Microcystis aeruginosaandOscillatoria agard‐hii) from different lakes in southeastern Norway were tested for toxicity toward freshly prepared rat hepatocytes. The toxicity effects were scored by means of morphological studies of the cells and by measuring leakage of the enzyme lactate dehy‐drogenase (LDH) from the cells. The results with the hepatocytes correspond well with results from the traditional mouse bioassay, concerning both ability to distinguish between toxic and nontoxic samples and estimation of relative toxicity. Morphological changes due to toxic effects on the plasma membrane appeared earlier than leakage of enzyme from damaged cells. The results indicate that the hepato‐cyte‐toxicity assay system might be well suited for screening purposes concerning water contamination by blue‐green algae.

ISSN:0098-4108    

DOI:10.1080/15287398609530931

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The purpose of this study was to determine whether cimetidine exerts a protective effect against toxicity of organophosphate pesticides requiring metabolic activation in mice and rats. In both species, pretreatment with cimetidine (75 mg/kg/ip) 30 min prior to methylparathion (MP) reduced lethality and delayed the onset of cholinergic signs of toxicity. In contrast when cimetidine was administered simultaneously with MP to mice, neither MP‐induced lethality nor cholinergic signs of toxicity were altered. Moreover, cimetidine pretreatment failed to decrease parathion‐induced toxicity in mice.

ISSN:0098-4108    

DOI:10.1080/15287398609530932

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The carcinogenic potential of triethanolamine was examined in F344 rats. Triethanolamine was dissolved in distilled water at levels of 0 (control), 1, and 2%, and groups of 50 males and 50 females were given these doses ad libitum as drinking water for 2 yr. The dose levels in females were reduced by half from wk 69, because of associated nephrotoxicity. A variety of tumors developed in all groups, including the control group, and alt tumors observed were histologically similar to spontaneous tumors in this strain of rats. No statistically significant increase of the incidence of any tumor was observed in the treated groups of both sexes by the chi‐square test. In this study, however, there was an increase in nephrotoxicity, which appeared to have an adverse effect on the life expectancy of the treated animals, especially of females. Therefore, an age‐adjusted statistical analysis on incidences of main tumors or tumor groups of both sexes was also done by methods recommended by Peto et al. (1980). The result showed that a positive trend (p < 0.05) was noted in the occurrence of hepatic tumors (neoplastic nodule/hepatocellular carcinoma) in males and of uterine endometrial sarcomas and renal‐cell adenomas in females. These tumors, however, have been observed spontaneously in this strain of rats, and their incidences in the control group of the present study were lower than those of our historical controls. These results may indicate that a positive trend in the occurrence of these tumors is not attributable to triethanolamine administration. Increased incidence of renal tumors in the female high‐dose group may have been connected with renal damage. Histological examination of renal damage observed in the treated groups, especially in the female high‐dose group, revealed acceleration of so‐called chronic nephropathy. In addition, mineralization of the renal papilla, nodular hyperplasia of the pelvic mucosa, and pyelonephritis with or without papillary necrosis were also observed. Thus, it is concluded that under these experimental conditions triethanolamine is not carcinogenic in F344 rats but is toxic to the kidneys.

ISSN:0098-4108    

DOI:10.1080/15287398609530933

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Young chickens fed hexachlorobenzene (HCB) or pentachlorophenol (PCP) for 14 d at 10 ppm in the diet contained body burdens of 573 or 362 μg, respectively. These diets were withdrawn (d 0) and replaced for 21 d with diets containing 5% mineral oil (MO), or 5% (CO), a bile‐acid‐binding resin, or the chickens were restricted in feed intake to 50% of controls (50‐RF), fed MO plus 50‐RF, or CO plus 50‐RF. Without any treatment during withdrawal, body burdens were reduced to 63% and 70% of the d 0 values for HCB and PCP, respectively. MO, CO, or 50‐RF reduced body burdens of HCB to 37% of d 0 burdens, but the combination treatments with 50‐RF reduced body burdens to 19% of d 0 values. PCP was at 35% of the d 0 burdens from 50‐RF, while all other treatments had reduced body burdens to nondetectable amounts of less than 0.7 μglbird by d 21 of withdrawal. Body fat was not reduced by mineral oil, but was reduced to some extent by CO, and was markedly reduced by 50‐RF. 50‐RF always reduced body burdens of PCP or HCB alone or in combination with MO or CO. These data are discussed in relationship to the nonbiliary excretion of xenobiotics.

ISSN:0098-4108    

DOI:10.1080/15287398609530934

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Twelve serum analytes [triglycerides, cholesterol, total and conjugated bilirubin, high‐density‐lipoprotein cholesterol (HDL‐C), alkaline phosphatase (AP), gammaglu‐tamyl transferase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), β‐glucuronidase (β‐glu), alanine aminopeptidase (AAP), and 5’ ‐nucleotidase (5'nuc)] were measured to investigate their correlation with exposure to polychlori‐nated biphenyls (PCBs) and 1,1,1‐trichloro‐2,2‐bis(p‐chlorophenyl)ethane (DDT). The relationship between serum lipids, lipophilic toxicants, and the analytes was also evaluated. The β‐glu, 5'nuc, triglycerides, cholesterol, and total bilirubin correlated positively and significantly with log concentrations of serum total PCBs and 1,1‐di‐chloro‐2,2‐bis(p‐chlorophenyl)ethylene (DDE), a metabolite of DDT. The more highly chlorinated PCBs (Aroclor 1260) had significant, positive correlations with several serum analytes, but the less chlorinated PCBs (Aroclor 1242) correlated significantly and negatively only with HDL‐cholesterol.

ISSN:0098-4108    

DOI:10.1080/15287398609530935

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Reproductive problems, including congenital malformations, reduced hatching success, and decreased survival of hatchlings, have been observed in colonial‐nesting water birds at the San Francisco Bay National Wildlife Refuge (SFBNWR). Twenty‐four black‐crowned night heron (Nycticorax nycticorax) eggs were collected from SFBNWR in 1983. Twelve of these were collected from separate nests when late‐stage embryos were pipping, and an additional egg was randomly collected from each nest for organochlorine analysis. Overt anomalies and skeletal defects were not apparent. Embryonic weights (with partially absorbed yolk sacs removed) were 15% lower (p < 0.05) in SFBNWR embryos compared to control embryos from the Patuxent Wildlife Research Center (PWRC). Crown‐rump length and femur length were shorter for SFBNWR embryos. The geometric mean polychlorinated biphenyl (PCB) concentration in SFBNWR eggs was 4.1 ppm wet weight, with a range of 0.8–52.0 ppm. A negative correlation (r = ‐0.61; p < 0.05) existed between embryonic weight and log‐transformed PCB residues in whole eggs collected from the same nest at SFBNWR, suggesting a possible impact of PCBs on embryonic growth. A correlation with embryonic weight did not occur for DDE [l,l‐dichloro‐2,2‐bis(p‐chlorophenyl) ethylene]residues. Liver microsomal aryl hydrocarbon hydroxylase activity was neither significantly elevated nor correlated with PCB, DDE, or PCB plus DDE log‐transformed residues. It is unknown whether the apparent association between PCBs and lower weight is persistent through hatching.

ISSN:0098-4108    

DOI:10.1080/15287398609530936

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Groups of male Long‐Evans rats 30, 50, or 70 d old were injected subcutaneously (sc) with a single dose of 0, 5.5, 11.5, or 24.6 μmol Cd/kg as cadmium chloride. All animals were killed 60 d after treatment. At 2 h prior to sacrifice, the rats were injected sc with 100 IU human chorionic gonadotrophin (hCG) to maximally stimulate serum testosterone concentrations. After sacrifice the testes, epididymides and seminal vesicles were removed and weighed. Cardiac blood was taken, and serum concentrations of testosterone (sT) and follicle‐stimulating hormone (sFSH) were determined. Sperm concentration in luminal fluid collected from the vas deferens was determined.

ISSN:0098-4108    

DOI:10.1080/15287398609530937

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Wistar rats were injected intratracheally with pyrite particles and after 6 and 12 mo, lungs were evaluated for histological changes. Results were compared with rats that were given particles of galena, lead silicate, travertine, and quartz. Under the light microscope no significant changes were observed in the lungs from animals treated with galena, lead silicate, and travertine. In the lungs from animals that received quartz, a typical nodular fibrosis was observed. Moreover, both pyrite‐treated rats and quartz‐treated rats developed pulmonary alveolar lipoproteinosis; the lesions were much less prominent andseverein animals injected with pyrite than with quartz. These results indicate that pyrite, like only a few other types of dust that are different from quartz, can evoke the development of pulmonary alveolar lipoproteinosis in rats.

ISSN:0098-4108    

DOI:10.1080/15287398609530938

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Three exposure regimens were used to study the time course of indicators of lung damage and recovery response to single or repeated exposures to phosgene (COCI2). Rats were sacrificed (1) immediately or throughout a 38‐d recovery period after inhalation of 7 ppm COCI2for 4 h, (2) at intervals during a 7‐h exposure to 1 ppm phosgene, or (3) at several time points throughout a 17‐d exposure to 0.125 and 0.25 ppm COCI2(4 h/d, 5 d/wk) and during a 21‐d recovery period. Regimen 7 revealed significantly elevated lung wet weight, lung nonprotein sulfhydryl (NPSH) content, and glucose‐6‐phosphate dehydrogenase (G6PD) activity that stayed elevated for up to 14 d. A significant decrease in body weight and food intake was observed 7 d after exposure. Regimen 2 caused a slight depression in NPSH content but did not affect G6PD activity. Regimen 3 animals showed sustained elevations in lung wet weight, NPSH content, and G6PD activity after 7 d of exposure. No significant changes in these endpoints were observed for the 0.125 ppm COCI2group. No consistent elevation in hydroxyproline content was seen at either exposure concentration. Light microscopic examination of lung tissue exposed to 0.25 ppm COCI2for 17 d revealed moderate multifocal accumulation of mononuclear cells in the centriacinar region. In summary, exposure to COCI2caused changes similar in most ways to those observed for other lower‐respiratory‐tract irritants.

ISSN:0098-4108    

DOI:10.1080/15287398609530939

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor