摘要:

AbstractRelationships have been established between the concentrations of mercury in human scalp hair and environmental or dietary mercury exposures. For chronic exposures, the hair/blood ratio for mercury is in the range 200:1–300:1, and scalp hair mercury concentrations of>5 ppm are indicative of mercury intoxication. These observations, coupled with the ease by which samples may be collected, transported and stored, support the use of hair analysis for evaluating mercury intoxication of the human bod

ISSN:0260-437X    

DOI:10.1002/jat.2550120203

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractOvariectomized mink were fed diets containing zearalenone (ZEN) at concentrations of 0, 10 or 20 ppm with or without 0.5% hydrated sodium calcium aluminosilicate (HSCAS) for 24 days. Zearalenone at 10 and 20 ppm caused a significant increase in uterine weights, while 20 ppm ZEN resulted in significantly higher vulva swelling scores when compared to controls. The presence of HSCAS in the diet did not alter these hyperestrogenic effects of ZEN. In a second experiment, female mink were provided diets containing 20 ppm ZEN, 20 ppm ZEN plus 0.5% HSCAS or a control diet from 1 January 1989 through whelping (25 April to 15 May 1989). The females were given an opportunity to mate with untreated proven breeder males beginning on 1 March (day 59 of exposure). ZEN did not have an effect on the number of females whelping but there was a significant increase in gestation length, a decrease in litter size and an increase in kit mortality from birth to 3 weeks of age when compared to the control group and the group receiving the combination of ZEN and HSCAS. These results suggest that HSCAS can alleviate some of the reproductive effects of ZEN which are not related to its estrogenic action.

ISSN:0260-437X    

DOI:10.1002/jat.2550120204

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractWe designed a breath sampler based on a tube which collects the final portion of exhaled air. The passage of successive fractions through a layer of activated charcoal is controlled by a three‐way valve. This system was validated in a controlled atmosphere ofn‐hexane and toluene at four concentrations between 12 and 110 mg m−3and 12 and 115 mg m−3, respectively. Uptake volumes of 0.1, 0.2 and 0.3 I were tested at relative humidities of 46% and 98%. There were no significant differences in the recoveries obtained under any of the conditions tested. We confirmed the reproducibility between successive samples in volunteers and exposed workers, and found no significant differences between the different sampling conditions studied. Our system enriches the sample in an adsorbent cartridge by collecting successive fractions of end‐exhaled breath from one or more exhalations until the amount required by the analytical method has been accumulated. It is portable, economical and highly operative in

ISSN:0260-437X    

DOI:10.1002/jat.2550120205

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractCyclic nucleotides play an important role in the regulation of fibroblast proliferation and collagen metabolism. In the present study, the antifibrotic potential of dibutyrylcAMP (Bt2cAMP) was evaluated in the bleomycin (BLM)‐hamster model of pulmonary fibrosis. Bt2cAMP (10 mg kg−1, s.c.) or saline (SA, s.c.) was given daily two days prior to the first intratracheal (i.t.) dose of BLM or SA and thereafter throughout the study. BLM or SA was instilled i.t. in three consecutive doses (2.5, 2.0 and 1.5 U 5ml−1kg−1) at weekly intervals. Hamsters were killed at 7, 14 and 20 days after the third i.t. instillation. Bt2cAMP significantly reduced the contents of lung hydroxyproline and lung thiobarbituric acid reactive substance equivalents in BLM‐treated animals at 7 and 14 days. Bt2cAMP significantly elevated lung superoxide dismutase activity in BLM‐treated animals at 7 days. Lung prolyl hydroxylase activity was significantly elevated at 14 and 20 days in SABLM‐ and Bt2cAMPBLM‐treated animals. The ratio of cAMP/cGMP was significantly reduced at all tone points in SABLM‐treated animals but only at 7 and 14 days in Bt2cAMPBLM‐treated animals. Bt2cAMP caused no significant changes in lung calcium and calmodulin levels and protein content of the bronchoalveolar lavage. BLM significantly increased various inflammatory cell counts in the lavage at all three time points. The cell counts in the Bt2cAMPBLM groups were generally lower at 7 days and higher at 20 days than those of the SABLM groups. Histological evaluation showed that the lungs of Bt2cAMPBLM‐treated hamsters progressed from an inflammatory cell lesion to a fibrotic lesion at a slower rate than the SABLM groups. It was concluded that Bt2cAMP attenuated BLM‐induced pulmonary fibrosis in hamsters in part by delaying the acute phase of th

ISSN:0260-437X    

DOI:10.1002/jat.2550120206

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractAcute toxicity of 2‐butyne‐1, 4‐diol (BYD) was evaluated in laboratory animals. The evaluation involved acute oral and dermal toxicity in rats, dermal and ocular irritation in rabbits and skin sensitization in guinea pigs. The oral LD50values for BYD were 132 mg kg−1in male rats and 176 mg kg−1in female rats. Post‐mortem histology showed severe damage in lungs, liver and kidneys. In surviving rats, moderate to severe degenerative changes were observed in the liver but only mild lesions in the kidneys. In acute dermal toxicity studies the test chemical was applied either as a solid substance or as 40% aqueous solution at a dose of 5 g kg−1for 24 h. Within 48 h of application of the diluted test material, half of the rats died. Liver and kidneys were the primary targets and different stages of degeneration, including necrosis, were observed. No deaths occurred after application of the solid substance. In rabbits, BYD was slightly irritant to skin and eyes. No allergic contact dermatitis was observed i

ISSN:0260-437X    

DOI:10.1002/jat.2550120207

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

Abstract2‐Butyne‐1,4‐diol was given to male and female Wistar Imp:DAK rats by oral gavage for 28 consecutive days in daily doses of 1, 10 or 50 mg kg−1day−1. After 28 days all animals were necropsied. Blood samples were obtained and selected organs were weighed and prepared for histological examination. Treatment‐related effects in the high‐dose group consisted of: fatal cases in both sexes; depressed body weight gain in males; increase of absolute and/or relative weights of liver and kidneys in both sexes; decreased red blood cell count, haematocrit value and haemoglobin concentration in female rats and elevated reticulocyte count and leukocyte count in both sexes; increased total serum protein content in females, elevated glucose concentration in males and higher activity of sorbitol dehydrogenase in both sexes; and hisiopathological evidence of hepatotoxicky and nephrotnxicity in decedents, and hepatic and splenic changes in survivors. Minor hepatic, splenic and erythrocytic changes were also found in some females given the middle dose. The dose of 1 mg kg−1day−1was considered to be the no‐observed‐effect level (NOEL), and 10 mg kg−1day−1the lowest‐ob

ISSN:0260-437X    

DOI:10.1002/jat.2550120208

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractCitrinin depresses the phosphorylation efficiency of rat renal cortical mitochondria, as inferred from the decrease of the respiratory control coefficient (RC) and ADP/O ratios. The transmembrane potential (Δψ) developed by energized mitochondria and the depolarization upon ADP addition are also decreased. Citrinin (1.0 mM) inhibits almost all enzymes linked to the respiratory chain and increases the activity of succinate cytochromecreductase and succinate oxidase (coupled). Malate and glutamate dehydrogenases are also inhibited. The inhibitory action of citrinin on phosphoryiation efficiency could be related to the following findings: the effect on complex I; the action on the ATP synthetase complex; the partial inhibition of the transmembrane potentia

ISSN:0260-437X    

DOI:10.1002/jat.2550120209

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractFive‐hundred and sixty Sprague‐Dawley rats were randomized into one control and three treatment groups (70 of each sex per group). Animals were treated by daiiy gavage with 0.0, 0.05, 0.5 and 2.5 mg kg−1acrokin in water (10 ml kg−1). These dosing levels were selected as a result ofa 6‐week range‐finding study. Ten rats of each sex per group were sacrificed at 1 year, and the remainder of the animals were treated for 102 weeks. Daily observations were made, and various clinical, hematological and urine parameters were measured after 3, 6, 12 and 18 months of treatment and immediately prior to termination. All animals, whether found dead or sacrificed, were subject to necropsy and both absolute and relative organ weights were recorded. An extensive array of tissues were examined microscopically for all test animals.The only effects noted for treated rats that were statistically different from controls were consistent depression of creatinine phosphokinase levels, which was difficult to explain, and consistent increases in early cumulative mortalities in both males and females. There was no significantly increased incidence of microscopic lesions in treated rats, whether neoplastic or non‐neoplastic. This study clearly demonstrates the lack of neoplastic response in Sprague‐Dawley rats as a result of being treated with acr

ISSN:0260-437X    

DOI:10.1002/jat.2550120210

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractAcetaminophen undergoes toxic conversion in the liver to a free‐radical intermediary which binds to glutathione.N‐Acetylcysteine acts as a glutathione precursor when natural stores are depleted, and is an effective antidote for acetaminophen overdose. Mushrooms containing amatoxins (such asAmanita phalloides) may undergo similar toxic conversion. However, in our amatoxin‐poisoned mouse model,N‐acetylcysteine (1.2 g kg−1) produced no change in survival or hepatic enzyme elevation compared to control animals. We conclude thatN‐acetylcysteine has no clinical role in the treatment ofAmanita phalloid

ISSN:0260-437X    

DOI:10.1002/jat.2550120211

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractA quantitative structure‐toxicology (LD50) relationship for someN‐alkylsuccinimides is presented. The relationship is based on a small and carefully selected training set using experimental design methodology. The good predictability, an overallr2value of 0.75, with such an approach is demonstrated. Factors such as largeN‐alkyl groups, substitution in the aromatic ring and a long side chain between the two nitrogens are favourable for low tox

ISSN:0260-437X    

DOI:10.1002/jat.2550120212

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY