摘要:

Adult rats of both sexes were given a single oral dose of [14C]patulin and were sacrificed at various time intervals from 4 hr to 7 days following administration of the mycotoxin. Two groups of rats were employed; the treated group had been exposed to daily oral doses of unlabeled patulin (dissolved in pH S.O citrate buffer) in utero and for 41–66 wk after weaning, while the controls were given the buffer only throughout gestation and for 38–81 wk after weaning. Approximately 49% of the administered14C radioactivity was recovered from feces and 36% from urine within 7 days after dosing. Most of the excretion of labeled material occurred within the first 24 hr. All of the14C activity detected in the urine samples was either metabolites and/or conjugates of the original [14C] patulin. About 1–2% of the total radioactivity was recovered as14CO2from expired air. Carbon‐14 radioactivity in various tissues and organs was determined throughout the 7 day period; the most significant retention site was the red blood cells.

ISSN:0098-4108    

DOI:10.1080/15287397709529580

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Binding to tissue carboxylesterases has been suggested as an important mechanism of detoxification for several organophosphates. In this study DDVP, malaoxon, and paraoxon were inactivated, in vitro, by mouse liver under assay conditions that were consistent with a binding mechanism of inactivation. Binding of the three organophosphates was inhibited in livers of mice pretreated, 18 hr before sacrifice, with TOTP (triorthotolyl phosphate, 125 mg/kg, ip). Previous studies have shown that similar TOTP treatment enhanced the toxicity of malaoxon and paraoxon but did not alter the toxicity of DDVP. Both DDT (50 mg/kg, ip, given 4, 3.5, and 2.5 days before sacrifice) and dieldrin (16 mg/kg, po, given 4 days before sacrifice) increased liver/body weight ratios and decreased the duration of pentobarbital‐induced loss of righting ability. Dieldrin increased liver carboxylesterase activity and liver binding of malaoxon and paraoxon but not of DDVP. In contrast, DDT did not increase liver carboxylesterase activity nor did it increase binding of malaoxon or paraoxon. Yet DDT pretreatment increased mouse liver binding of DDVP. Neither DDT nor dieldrin pretreatments altered the toxicity of subsequently administered DDVP. These results support the hypothesis that carboxylesterase binding does not represent an important mechanism for DDVP detoxification in the mouse. In other experiments, in vitro inactivation of malaoxon by binding was inhibited in livers of mice given DD VP (30 mg/kg, ip) 30 min before sacrifice. Similar DDVP pretreatment potentiated the anticholinesterase action of malaoxon (10 mg/kg, ip). Thus, even though DDVP toxicity was not altered by DDT‐ or dieldrin‐induced changes in organophosphate binding, DDVP inhibited malaoxon binding and increased malaoxon toxicity.

ISSN:0098-4108    

DOI:10.1080/15287397709529581

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Pentachlorophenol affected the composition of communities of estuarine organisms developed in sand from planktonic larvae in estuarine water that flowed through ten control aquaria and ten aquaria per exposure concentration averaging 7, 76, or 622 μg/liter. Annelids, arthropods, and mollusks were the numerically dominant phyla when animals were collected in a 1‐mm‐mesh sieve after 9 wk of exposure. Mollusks were markedly fewer at 7 μg/liter; annelids and arthropods at 76 μg/liter. Almost no animals occurred at 622 μg/liter. The total numbers of individuals and species were significantly less (α = 0.01) in aquaria exposed to 76 μg/liter than in those unexposed or exposed to 7 μg/liter.

ISSN:0098-4108    

DOI:10.1080/15287397709529582

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The pharmacokinetics and metabolism of 1,4‐dioxane were determined in four healthy male volunteers exposed to 50 ppm dioxane vapor for 6 hr. Samples of blood and urine collected during and after the exposure were analyzed for dioxane and its metabolite β‐hydroxyethoxyacetic acid (HEAA) by gas chromatography‐mass spectrometry. A pharmacokinetic model with associated parameters was constructed to describe the fate of dioxane and HEAA in humans. The model was compared to a model constructed previously for dioxane in rats. This comparison facilitates assessment of the hazard to humans of dioxane exposure by extrapolation of toxicological information obtained in rats.

ISSN:0098-4108    

DOI:10.1080/15287397709529583

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Ozone and the oxides of sulfur are common environmental pollutants. The acute pulmonary lesions caused by ozone and sulfuric acid mist in rats and guinea pigs have been characterized. Rats are not affected by sulfuric acid mist in concentrations up to 100 mg/m3except for reduced body weight at the higher doses. A true alveolitis develops in guinea pigs exposed to more than 20 mg/m3sulfuric acid mist. The ozone lesion is primarily confined to the terminal bronchioles and proximal alveoli. In combination studies with up to 2 ppm ozone and up to 10 mg/m3sulfuric acid mist, the pulmonary lesion and lung/body weight data were essentially the same as in exposure to ozone alone, and the number of statistically significant synergistic effects in rats and guinea pigs was about what one would expect to observe by chance alone.

ISSN:0098-4108    

DOI:10.1080/15287397709529584

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Mice were exposed to 0, 13, or 1,300 ppm lead in drinking water for 18 months. The immunological assays examined were mitogen (lipopolysaccharide E. coli, concanavalin A, and phytohemagglutinin‐P) stimulation of lymphocytes; erythrocyte‐antibody (EA), erythrocyte‐antibody‐complement (EAC), and phagocytosis of macrophages; and EAC of splenic lymphocytes. As measured by the majority of these assays, the low dosage (13 ppm) of lead tended to stimulate certain immune responses (lymphocyte mitosis, EA, and EAC) while the high dosage (1,300 ppm) did not provoke an appreciable alteration. The results were interpreted by comparing data on aged mice with data on young adult mice. It was apparent from this comparison that the aged mice were naturally immunosuppressed. Therefore, the results obtained from lead‐exposed mice were unpredictable.

ISSN:0098-4108    

DOI:10.1080/15287397709529585

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Male Sprague‐Dawley rats were exposed for 4 hr to 1,1‐dichloroethylene (1,1‐DCE) by inhalation following an 18 hr fast. They were killed at 6 hr. Under these circumstances, prior thyroidectomy caused a decrease in the severity of the injury as measured by elevation of serum alanine‐α‐ketoglutarate transaminase (AKT), while thyroxine pretreatment (50 \ig per rat sc for 7 days) enhanced the hepatotoxicity of 1,1‐DCE as measured by lethality and serum AKT elevation. Chemical thyroidectomy using either propylthiouracil (30 mg/kg po for 7 days) or methimazole (15 mg/kg po for 7 days) also provided a degree of protection. Thyroidectomy, surgical or chemical, was associated with an increase in hepatic glutathione concentration, while thyroxine decreased the hepatic concentration of this nucleophile. Livers from rats exposed to 1,1‐DCE were found to have decreased in vitro oxygen uptake when supplied with succinate and ADP. This form of injury preceded the elevation in serum AKT, which occurred at 4 hr. Subcellular fractionation of livers from fed or fasted rats exposed to air or 1,1‐DCE showed that the heavy and light mitochondrial fractions from fasted, exposed rats had the largest decrease in glutathione concentration relative to the other groups. 1,1‐DCE exposure was associated with decreased glutathione concentration, but subtractions from fasted rats generally had the largest decreases. Serum sorbitol dehydrogenase, a cytoplasmic marker, was positively correlated to changes in serum ornithine carbarnoyl transaminase, a mitochondrial marker, suggesting that mitochondrial damage may occur before or at the same time as cytoplasmic membrane rupture. These latter findings are consistent with previously reported histologic observations. Based on these data, a mechanism for 1,1‐DCE is proposed.

ISSN:0098-4108    

DOI:10.1080/15287397709529586

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The effect of anemia on the lead content of blood, red cells, and tissue was studied in rats given oral lead, 54 mg/kg‐day for 6 days. The 16 rats made anemic (hematocrit, 26%) by bleeding on days 1, 3, and 5 had significantly higher concentrations of lead in the kidney, liver, red cells, blood, and brain (but not in the bone marrow). Increases in blood lead in anemic subjects were correlated with the concentrations in red cells, kidney, and liver. The greater increase in the lead content of all tissues of the anemic rats is consistent with increased lead absorption in anemia and is considered relevant to the clinical coexistence of anemia and lead poisoning.

ISSN:0098-4108    

DOI:10.1080/15287397709529587

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Depletion of serotonin or norepinephrine in male rats by pretreatment with p‐chlorophenylalanine or DL‐α‐methyl‐p‐tyrosine, respectively, failed to reduce the lethality of the monoamine oxidase‐inhibiting acaricide, chlordimeform. Administration of phenylephrine, a directly acting a‐adrenergic agonist, with chlordimeform did not increase the lethality of chlordimeform. Thus, monoamine oxidase inhibition by chlordimeform does not seem to contribute to its lethality.

ISSN:0098-4108    

DOI:10.1080/15287397709529588

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The effect of 2‐chloroethanol on the activities of hepatic microsomal enzymes in the rat has been studied. A significant reduction in activities of drug‐metabolizing enzymes (aminopyrine H‐demethylase, coamarin 3‐hydroxylase) and a marked decrease of glucose 6‐phosphatase were seen In both sexes given dose levels of 20 mg/kg sc doily for 7 days. Inosine diphosphatase activity remained unaltered. In male rats given 3 or 10 mg/kg, a trend in the inhibition of drug metabolism was found. A single dose of 50 mg/kg caused no apparent change in the activities of the enzymes measured.

ISSN:0098-4108    

DOI:10.1080/15287397709529589

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor