Journal of toxicology and environmental health最新文献_第5页

Effects of inducers and inhibitors on the microsomal metabolism of styrene to styrene oxide in mice. 诱导剂和抑制剂对小鼠苯乙烯到苯乙烯氧化物微粒体代谢的影响。

Journal of toxicology and environmental health Pub Date : 1997-08-08 DOI: 10.1080/00984109708984038

G P Carlson

{"title":"Effects of inducers and inhibitors on the microsomal metabolism of styrene to styrene oxide in mice.","authors":"G P Carlson","doi":"10.1080/00984109708984038","DOIUrl":"https://doi.org/10.1080/00984109708984038","url":null,"abstract":"Styrene is both hepatotoxic and pneumotoxic in mice, with non-Swiss albino (NSA) mice being more sensitive than Swiss (CD-1) mice. The toxicity of styrene is potentiated by treatment with phenobarbital, beta-naphthoflavone, or pyridine. Since the toxicity of styrene is generally associated with its metabolism to styrene oxide (SO), the formation of SO by hepatic and pulmonary microsomes of NSA and CD-1 mice was measured to examine correlations with toxicity. Both enantiomers of SO were quantified since the R-SO enantiomer is more toxic than the S-SO enantiomer. No strain differences in rates of styrene metabolism or enantiomeric ratio were observed in control mice or mice treated with inducers. Pyridine, an inducer of CYP2E1, increased S-SO but not R-SO formation in liver. Phenobarbital, an inducer of CYP2B, increased the production of both enantiomers. beta-Naphthoflavone, an inducer of CYP1A, had no effect. None of the inducers had any effect in lung. Addition of the CYP2E1 inhibitor diethyldithiocarbamate decreased the formation of both enantiomers in both tissues from control mice, whereas 5-phenyl-1-pentyne (an inhibitor of CYP2F2) inhibited metabolism primarily in lung. In both control and phenobarbital-treated mice, SKF525A inhibited both R-SO and S-SO in liver but only S-SO in lung. Thus there are tissue differences in metabolism and susceptibility to induction and inhibition but no strain differences in metabolism to explain differences in susceptibility to styrene-induced toxicity.","PeriodicalId":17524,"journal":{"name":"Journal of toxicology and environmental health","volume":"51 5","pages":"477-88"},"PeriodicalIF":0.0,"publicationDate":"1997-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/00984109708984038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20177614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 44

Metabolism and disposition of dimethyl hydrogen phosphite in rats and mice. 大鼠和小鼠亚磷酸二甲基氢的代谢和处置。

Journal of toxicology and environmental health Pub Date : 1997-08-08 DOI: 10.1080/00984109708984039

A A Nomeir, H B Matthews

{"title":"Metabolism and disposition of dimethyl hydrogen phosphite in rats and mice.","authors":"A A Nomeir, H B Matthews","doi":"10.1080/00984109708984039","DOIUrl":"https://doi.org/10.1080/00984109708984039","url":null,"abstract":"A study of dimethyl hydrogen phosphite (DMHP) by the National Toxicology Program (NTP) indicated that chronic administration by oral gavage resulted in an increased incidence of neoplastic lesions in the lungs and forestomachs of Fischer 344 rats but not in B6C3F1 mice. The current study was designed to evaluate the metabolic basis, if any, of this species selectivity by studying the metabolism and disposition of [14C]DMHP in the respective strains of rats and mice. Results of this study indicate that DMHP administered at a range of dose of 10-200 mg/kg was readily and near completely absorbed from the gastrointestinal tracts of rats and mice. DMHP-derived radioactivity was eliminated primarily as CO2 in the expired air, 44-57%, and urine, 28-49%, and very little was collected in feces, 1-2%, or as volatile organics, 2-3%. DMHP-derived radioactivity was widely distributed in tissues of rats and mice, with the highest concentrations observed in the liver, kidneys, spleen, lungs, and forestomach, and the lowest in brain, skeletal muscle, and adipose tissue. The disappearance of radioactivity from mouse tissues was approximately twice as rapid as from rat tissues. In vitro, DMHP was metabolized to formaldehyde by the microsomal fractions of liver, lungs, kidneys, forestomach, and glandular stomach. In vivo, DMHP was metabolized to the product of demethylation, monomethyl hydrogen phosphite (MMHP), which was excreted in urine. Results of this study indicate that the NTP carcinogenicity study with DMHP was carried out within the dose range in which the absorption, metabolism, and disposition of DMHP are linear in both species. Apparent species-dependent differences in the metabolism and disposition of DMHP are limited to the more rapid metabolism and elimination by the mouse. Therefore, the species-dependent variations in the carcinogenicity of DMHP are most likely attributable to factors other than metabolism and disposition.","PeriodicalId":17524,"journal":{"name":"Journal of toxicology and environmental health","volume":"51 5","pages":"489-501"},"PeriodicalIF":0.0,"publicationDate":"1997-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/00984109708984039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20177615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Pathobiology of lipopolysaccharide. 脂多糖的病理生物学。

Journal of toxicology and environmental health Pub Date : 1997-08-08 DOI: 10.1080/00984109708984034

P R Mayeux

引用次数: 210

Morphometric changes in the prepubertal female rat thyroid gland following acute exposure to 2,2',4,4'-tetrachlorobiphenyl and Aroclor 1242. 急性暴露于2,2'，4,4'-四氯联苯和阿罗氯1242后青春期前雌性大鼠甲状腺形态的变化。

Journal of toxicology and environmental health Pub Date : 1997-08-08 DOI: 10.1080/00984109708984040

A Saeed, L G Hansen

{"title":"Morphometric changes in the prepubertal female rat thyroid gland following acute exposure to 2,2',4,4'-tetrachlorobiphenyl and Aroclor 1242.","authors":"A Saeed, L G Hansen","doi":"10.1080/00984109708984040","DOIUrl":"https://doi.org/10.1080/00984109708984040","url":null,"abstract":"Weanling female Sprague-Dawley rats were given either 2 or 5 consecutive daily doses of 30 mg/kg 2,2',4,4'-tetrachlorobiphenyl (CB 47) or a total dose of 120 mg/kg Aroclor 1242 divided into 2, 3, or 5 daily doses by intraperitoneal injection. One day after the final dose, serum total thyroxine (T4) was determined and thyroid glands were collected and prepared for morphometric analysis. Serum T4 increased between 20 and 25 d of age, but declined to 35-52% of controls by d 25 in PCB-treated rats. In rats receiving only 2 doses of CB 47, the declines in serum T4 were more modest but the thyroid follicular epithelial cell height increased from 9 microns to 10-12 microns and the colloid area decreased from 1100 microns2 to 800-900 microns2. In Aroclor 1242-treated rats, follicular cell height increases and colloid area decreases were somewhat greater; serum T4 was higher (partially restored) in the rats having received earlier doses. The rapid response of the thyroid gland to moderate decreases in serum T4 attenuates the observed decrease in T4 and may mask effects on T4 metabolism in short-term structure-activity studies. Morphometric measurements may be helpful in characterizing early and/or transient responses to toxicants such as PCBs that have multiple endocrine disrupting effects.","PeriodicalId":17524,"journal":{"name":"Journal of toxicology and environmental health","volume":"51 5","pages":"503-13"},"PeriodicalIF":0.0,"publicationDate":"1997-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/00984109708984040","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20177616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 37

Effect of dosing vehicle on the hepatotoxicity of CCl4 and nephrotoxicity of CHCl3 in rats. 给药载体对大鼠CCl4肝毒性和CHCl3肾毒性的影响。

Journal of toxicology and environmental health Pub Date : 1997-08-08 DOI: 10.1080/00984109708984037

P Raymond, G L Plaa

{"title":"Effect of dosing vehicle on the hepatotoxicity of CCl4 and nephrotoxicity of CHCl3 in rats.","authors":"P Raymond, G L Plaa","doi":"10.1080/00984109708984037","DOIUrl":"https://doi.org/10.1080/00984109708984037","url":null,"abstract":"There are conflicting results in the literature concerning the effect of gavage vehicle, corn oil (CO) versus aqueous suspension, on the toxicity of haloalkanes. The purpose of our study was to assess the influence of oral dosing vehicle on the acute hepatotoxicity of CCl4 and nephrotoxicity of CHCl3. Male Sprague-Dawley rats, fed ad libitum, were treated (po) with single doses of CCl4 or CHCl3 using corn oil (CO), or an aqueous preparation (5%) of Emulphor (EL620) or Tween-85 (Tw-85) as vehicle (10 ml/kg). Rats were killed 48 h after treatment. Blood was collected for plasma alanine aminotransferase (ALT) determination and renal cortical slices were prepared for p-aminohippuric acid (PAH) incorporation. The comparison, between gavage vehicles, of the slopes and ED50 of the dose-response curves, although not significantly different, indicated clear trends for enhanced potency with CO for CHCl3 nephrotoxicity but not for CCl4 hepatotoxicity. However, ALT values, a measure of the severity of effect for CCl4, also indicated that CO, when compared to EL620 and Tw-85, tended to enhance CCl4 hepatotoxicity at low toxicity incidence. Furthermore, CO clearly enhanced the severity of effect for CHCl3 nephrotoxicity, as measured by the slice-to-medium PAH ratios, at high dosage. The greater severity of the lesion produced by exposure to these chemicals, when administered in CO, is consistent with the trends observed for their potency (dose-response curves). Our results agree with an increased toxicity of haloalkanes by the gavage vehicle CO reported in the literature. Thus, CO should be considered a potential confounder in hepato- and nephrotoxicity assays.","PeriodicalId":17524,"journal":{"name":"Journal of toxicology and environmental health","volume":"51 5","pages":"463-76"},"PeriodicalIF":0.0,"publicationDate":"1997-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/00984109708984037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20178350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Hair selenium as a monitoring tool for occupational exposures in relation to clinical profile. 头发硒作为职业性暴露与临床关系的监测工具。

Journal of toxicology and environmental health Pub Date : 1997-08-08 DOI: 10.1080/00984109708984035

A K Srivastava, B N Gupta, V Bihari, J S Gaur, N Mathur

引用次数: 15

Effect of environmental conditions on the penetration of benzene through human skin. 环境条件对苯通过人体皮肤渗透的影响。

Journal of toxicology and environmental health Pub Date : 1997-08-08 DOI: 10.1080/00984109708984036

J S Nakai, I Chu, A Li-Muller, R Aucoin

{"title":"Effect of environmental conditions on the penetration of benzene through human skin.","authors":"J S Nakai, I Chu, A Li-Muller, R Aucoin","doi":"10.1080/00984109708984036","DOIUrl":"https://doi.org/10.1080/00984109708984036","url":null,"abstract":"The in vitro penetration of [14C]benzene through freshly prepared human skin was examined under a variety of skin conditions associated with swimming and bathing. The experimental system utilized a recirculating donor solution and a flow-through receiver solution, and was modified to accommodate the analysis of volatiles. The permeability coefficient of 0.14 cm/h under standard conditions at 26 degrees C was found to increase to 0.26 cm/h at 50 degrees C and decrease to 0.10 cm/h at 15 degrees C. Storage of the skin at- 20 degrees C did not affect the penetration of benzene. Application of baby oil, moisturizer, or insect repellant to the skin before exposure under standard conditions did not affect the flux of benzene, but a significant increase was observed when the skin was pretreated with sunscreen (permeability coefficient 0.24 cm/h). These results suggest that risk assessment or exposure modeling for benzene and other environmental contaminants should account for appropriate changes in the environmental conditions when considering the dermal route of exposure.","PeriodicalId":17524,"journal":{"name":"Journal of toxicology and environmental health","volume":"51 5","pages":"447-62"},"PeriodicalIF":0.0,"publicationDate":"1997-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/00984109708984036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20178349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 35

Perspectives on Canadian field studies examining the potential of pulp and paper mill effluent to affect fish reproduction. 加拿大实地研究的观点，研究纸浆和造纸厂废水对鱼类繁殖的影响。

Journal of toxicology and environmental health Pub Date : 1997-07-01 DOI: 10.1080/00984109708984029

T G Kovacs, R H Voss, S R Megraw, P H Martel

{"title":"Perspectives on Canadian field studies examining the potential of pulp and paper mill effluent to affect fish reproduction.","authors":"T G Kovacs, R H Voss, S R Megraw, P H Martel","doi":"10.1080/00984109708984029","DOIUrl":"https://doi.org/10.1080/00984109708984029","url":null,"abstract":"The results and interpretations of published Canadian field studies on the reproductive status of fish in waters receiving pulp and paper mill effluent discharges were reviewed. Most of the information was obtained from indicator measurements such as gonad size, fecundity, and serum steroid levels in wild fish sampled at reference and effluent-exposed sites. Difficulties in selecting appropriate sampling sites, natural variability, and the ecological relevance of the indicator measurements were identified as major complicating factors for the interpretation of the field data. Consequently, it was not possible to conclude to what extent, if any, widespread effects on fish reproduction are being caused by pulp and paper mill effluents or that specific manufacturing processes are causing such effects. Further research on the normal variability and predictive capability of reproductive indicators, for example, using an integrated approach (i.e., laboratory testing, mesocosm studies, and field work), is recommended.","PeriodicalId":17524,"journal":{"name":"Journal of toxicology and environmental health","volume":"51 4","pages":"305-52"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/00984109708984029","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20147919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 32

Journal of toxicology and environmental health Pub Date : 1997-07-01 DOI: 10.1080/00984109708984031

T J Weber, Y Y Fan, R S Chapkin, K S Ramos

{"title":"Growth-related signaling in vascular smooth muscle cells is deregulated by TCDD during the G0/G1 transition.","authors":"T J Weber, Y Y Fan, R S Chapkin, K S Ramos","doi":"10.1080/00984109708984031","DOIUrl":"https://doi.org/10.1080/00984109708984031","url":null,"abstract":"Experiments have been conducted to examine the impact of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on growth-related signaling in vascular smooth muscle cells (SMCs). A 40% reduction of peak DNA synthesis was observed in SMCs only when TCDD was added during the G0/G1 transition of the cell cycle. Enhanced phosphorylation of several endogenous proteins during this period was coincident with increased tyrosine kinase activity as early as 15 min following TCDD challenge. No changes in protein phosphorylation status occurred in cells treated with TCDD during the G1/S transition or during S phase. Cotreatment of quiescent SMCs with 10 nM TCDD and serum for 3 h reduced serum-inducible binding activity to a 12-O-tetradecanoyl phorbol 13-acetate responsive element (TRE) by approximately 40%. No alterations of constitutive TRE binding were observed in quiescent SMCs treated with TCDD for up to 5 h. These data show that mitogen-related signaling in vascular SMCs is modulated by TCDD selectively during the G0/G1 transition, and these effects influence the growth behavior of these cells.","PeriodicalId":17524,"journal":{"name":"Journal of toxicology and environmental health","volume":"51 4","pages":"369-86"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/00984109708984031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20147921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Systemic toxicity of dermally applied crude oils in rats. 皮肤外用原油对大鼠的全身毒性。

Journal of toxicology and environmental health Pub Date : 1997-07-01 DOI: 10.1080/00984109708984032

M H Feuston, C R Mackerer, C A Schreiner, C E Hamilton

{"title":"Systemic toxicity of dermally applied crude oils in rats.","authors":"M H Feuston, C R Mackerer, C A Schreiner, C E Hamilton","doi":"10.1080/00984109708984032","DOIUrl":"https://doi.org/10.1080/00984109708984032","url":null,"abstract":"Two crude oils, differing in viscosity (V) and nitrogen (N) and sulfur (S) content, were evaluated for systemic toxicity. In the Crude I (low V, low N, low S) study, the material was applied to the clipped backs of rats at dose levels of 0, 30, 125, and 500 mg/kg. In the Crude II (high V, high N, moderate S) study, the oil was applied similarly at the same dose levels. The crude oils were applied for 13 wk, 5 d/wk. Exposure sites were not occluded. Mean body weight gain (wk 1-14) was significantly reduced in male rats exposed to Crude II; body weight gain of all other animals was not adversely affected by treatment. An increase in absolute (A) and relative (R) liver weights and a decrease in A and R thymus weights were observed in male and female rats exposed to Crude II at 500 mg/kg; only liver weights (A and R) were adversely affected in male and female rats exposed to Crude I. In general, there was no consistent pattern of toxicity for serum chemistry endpoints; however, more parameters were adversely affected in Crude II-exposed female rats than in the other exposed groups. A consistent pattern of toxicity for hematology endpoints was observed among male rats exposed to Crude I and male and female rats exposed to Crude II. Parameters affected included: Crudes I and II, red blood cell count, hemoglobin, and hematocrit; Crude II, platelet count. Microscopic evaluation of tissues revealed the following treatment-related findings: Crude I, treated skin, thymus, and thyroid; Crude II, bone marrow, treated skin, thymus, and thyroid. The LOEL (lowest observable effect level) for skin irritation and systemic toxicity (based on marginal effects on the thyroid) for both crude oils was 30 mg/kg; effects were more numerous and more pronounced in animals exposed to Crude II. Systemic effects are probably related to concentrations of polycyclic aromatic compounds (PAC) found in crude oil.","PeriodicalId":17524,"journal":{"name":"Journal of toxicology and environmental health","volume":"51 4","pages":"387-99"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/00984109708984032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20147922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6