ISSN:0098-4108    

DOI:10.1080/15287398709530975

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Forty shoe factory workers who were exposed to hexane were investigated to see if there was a correlation between electroneuromyographic changes indicative of neuropathy and urinary excretion of 2,5‐hexanedione. Urinary samples were analyzed for the presence of the metabolic products of n‐hexane and its isomers. Electrodiagnostic examination was carried out following the urinary sampling. A rating scale was used to obtain a cumulative numeric index of electrodiagnostic findings. 2,5‐Hexane‐dione and γ‐valerolactone were discovered in all cases, while 2‐hexanol was found in 11 cases. 2,5‐Hexanedione was the main metabolite in most cases (39 of 40). Only in 1 case was a low level of 2‐methyl‐2‐pentanol detected; 3‐methyl‐2‐pentanol was never detected. Metabolic products of cyclohexane were present in about one‐fifth of the cases, while trichloroethanol, a metabolic product of trichloroethylene, was nearly always present, all at very low concentrations. Electromyographic abnormalities significant for early detection of toxic polyneuropathy were found in 14 cases.

ISSN:0098-4108    

DOI:10.1080/15287398709530976

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The effects of pentachlorophenol (PCP) on selected parameters reflecting immunocompetence of female B6C3F1 mice were measured following subchronic exposure (14 d) and direct exposure in culture. Daily exposure was by gastric intubation of 10, 30, or 100 mg/kg of technical‐grade PCP (PCP‐T), or 100 mg/kg of EC‐7, a PCP preparation purified to reduce contamination (PCP‐P), or 100 mg/kg of the vehicle, corn oil. There were no effects on the antibody responses of spleen‐cell suspensions from either PCP‐T‐ or PCP‐P‐treated mice stimulated with antigen in culture. In contrast, when mice were immunized during the exposure to PCP‐T, there was a dose‐related suppression of the IgM antibody response to sheep red blood cells (SRBC) measured on both d 4 (peak day) and d 5. There was no change in the antibody response of mice exposed to PCP‐P. The differential activity was not observed following direct addition, since both PCP‐T and PCP‐P suppressed the in vitro antibody response by spleen‐cell suspensions from untreated mice. The suppression was associated with a decrease in cell viability, indicating that both preparations were directly cytotoxic. These results indicate that the in vitro antibody assay will be of limited value in determining the mechanism of immunosuppression by PCP. The lack of effect on the antibody response by splenocytes from PCP‐T‐treated mice indicates that the dysfunction is not due to a direct suppression of the capabilities of immunocompetent cells.

ISSN:0098-4108    

DOI:10.1080/15287398709530977

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A number of sites in the state of Missouri have been contaminated with polychlorinated dibenzodioxins and dibenzofurans as a result of improper waste‐oil application for dust control. In addition to these compounds, relatively high levels of 1,2,4,5,7,8‐hexachloro(9H)xanthene (1,2,4,5,7,8‐HCX), a by‐product of hexachlorophene manufacture, were also detected. Unlike the dibenzodioxins and dibenzofurans, no animal toxicity data are available on the chlorinated xanthenes. In view of the potential importance of this novel class of environmental contaminants, studies were conducted to examine the acute oral toxicity in guinea pigs and in vitro “dioxin‐like” activity of 1,2,4,5,7,8‐HCX. Animals administered a single oral dose of 0.02, 0.1, 0.5 or 2.5 mg 1,2,4,5,7,8‐HCX/kg in corn oil and sacrificed 42 d later exhibited no treatment‐related pathology. Guinea pigs given 12.5 mg/kg displayed mild to moderate distension and histologically observable subserosal edema of the urinary bladder, in addition to mild fatty vacuolization of pancreatic acinar cells. These alterations were considered to be of minimal toxicological significance. No compound‐ or dose‐related mortality, body weight loss, or organ weight changes were noted at any dose level. Results using an in vitro bioassay for “dioxin‐like” activity confirmed preliminary data suggesting that 1,2,4,5,7,8‐HCX is about 106times less potent than 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (2,3,7,8‐TCDD) in this assay system. These findings indicate that 1,2,4,5,7,8‐HCX may represent a relatively low environmental hazard compared to 2,3,7,8‐TCDD.

ISSN:0098-4108    

DOI:10.1080/15287398709530978

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In vivo effect of toxaphene on calcium pump activity in rat brain P2fraction was studied. Male Sprague‐Dawley rats (200–250 g) were dosed with toxaphene at 0, 25, 50, and 100 mg/kg · d for 3 d and sacrificed 24 h after last dose. Ca2+‐ATPase activity and45Ca2+uptake were determined in brain P2fraction. Toxaphene decreased both Ca2+‐ATPase activity and45Ca2+uptake, and the reduction was dose‐dependent. Both substrate and Ca2+activation kinetics of Ca2+‐ATPase indicated noncompetitive type of inhibition, as evidenced by decreased catalytic velocity but not enzyme‐substrate affinity. The decreased Ca2+‐ATPase activity and45Ca2+uptake were restored to normal level by exogenously added calmodulin, which increased both velocity and affinity. The inhibition of Ca2+‐ATPase activity and45Ca2+uptake and restoration by calmodulin suggests that toxaphene may impair active calcium transport mechanisms by decreasing levels of calmodulin.

ISSN:0098-4108    

DOI:10.1080/15287398709530979

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Male Wistar rats were exposed to aqueous [14C]ethylenediamine (EDA) solutions (10, 25, or 50%) percutaneously over a 7 × 7 cm area on the back with occlusion for 24 h. For each rat dosed, three types of studies were conducted: (1) plasma kinetics, (2) material balance, and (3) histological evaluation, including autoradiography of the skin sample from the dosing area. Adequate kinetic measurements were obtained only from animals treated with 25 and 50% EDA, but not from the 10% treatment group, due to analytical limitations. The uptake of [14C]EDA percutaneously by the rat was relatively slow in comparison with uptake following peroral or endotracheal administration. The absorption of EDA by the animals was estimated to be greater than 61, 55, and 12%, respectively, for the 50, 25, and 10% treatment groups. A large portion (11–32%) of the dose was left on/in the dosing area. Urinary excretion was the predominant route for the disposition of EDA. The recovery of the administered dose was low (70–83%), possibly due to volatilization of EDA from the skin during dosing and holding. Histologic examination of skin sections (dosing areas) revealed a normal, intact epidermis in rats dosed with 10% EDA, but full‐thickness epidermal necrosis in rats dosed with 25% or 50% EDA solutions. The damage of the epidermis apparently enhanced the penetration of EDA. Autoradiographic preparations revealed a concentration of the [14C]EDA radiolabel over the keratin layer and hair shafts.

ISSN:0098-4108    

DOI:10.1080/15287398709530980

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The histological disturbances occurring from the dermal application of low, medium, and high doses of phosphamidon‐92 (technical) to rats as observed by light microscope and analysis of hematobiochemical parameters of blood are presented. Groups of 10 male and 10 female albino rats (Wistar strain) were treated with the test material at dose levels of 0.48 (low), 2.2 (medium), and 3.98 (high) mg/kg · d for 3 wk, followed by a 2‐wk observation period. During application, a reduction in food intake and in body weight was recorded with all three treatments. However, gain in body weight and food intake resumed during the observation period and was marked with the high‐dose treatment only. Symptoms like hypersalivation and frothing were noticed in both the sexes, as well as a relative decrease in liver weight and gross pathological alterations on microscopical examination of skin, lung, kidney, and testis; significant alterations in some hematobiochemical parameters of blood were observed.

ISSN:0098-4108    

DOI:10.1080/15287398709530981

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The effects of reducing the tar and nicotine concentration of cigarette smoke were examined in a rat model of smoke‐augmented, porcine pancreatic elastase‐ (PPE‐) induced, pulmonary emphysema. Sixty‐eight female Long‐Evans rats were divided approximately evenly into seven groups: control, PPE, PPE plus sham smoke, high‐tar/ nicotine cigarette smoke (2R1; 38.8 mg total particulate matter and 2.2 mg nicotine per cigarette), low‐tar/nicotine cigarette smoke (1R4F; 10.8 mg total particulate matter and 0.8 mg nicotine per cigarette), PPE + 2R1, and PPE + 1R4F. Three days after intra‐tracheal administration of PPE (400 IU/kg), animals in the smoke‐treated groups were exposed to 8–10 puffs of cigarette smoke daily, 7 d/wk for 12 wk. Sham‐treated animals received room air in place of cigarette smoke. At the conclusion of the exposures, pulmonary function tests were performed under general anesthesia. Cigarette‐smoke exposure alone did not produce significant changes in pulmonary function. Elastase‐treated groups demonstrated significant increases in total lung capacity, functional residual capacity, and dynamic and static compliance, as well as significant decreases in carbon monoxide (CO) diffusing capacity and CO diffusion coefficient. Morphometric measurements of mean linear intercept demonstrated a loss of alveolar fine structure with enlargement of distal airspaces in PPE‐treated rats. Exposure to either 2R1 or 1R4F cigarette smoke significantly enhanced many of the emphysematous changes produced by PPE, but there were no significant differences between the effects of the two smokes. These data indicate that reducing the tar and nicotine concentration of cigarette smoke does not lessen its ability to augment PPE‐induced pulmonary emphysema in the rat.

ISSN:0098-4108    

DOI:10.1080/15287398709530982

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

We have evaluated the effect of the perfluorinated fatty acids pentadecafluoro‐n‐octanoic acid (PFOA) and nonadecafluoro‐n‐decanoic acid (NDFDA) on the ability of a human B‐lymphoblastoid cell line to bind the lipid‐binding, membrane‐impermeant, fluorescent dye merocyanine 540 (MC540). Subtoxic concentrations of perfluorinated fatty acids (0.9 mM PFOA; 0.5 mM NDFDA) greatly diminish binding of MC540 by normal plasma membranes, as determined by fluorescence flow cytometry. When perfluorinated fatty acids are added to cells at toxic or lethal concentrations (1.2 mM PFOA; 0.75 mM NDFDA), MC540 binding increases dramatically, with entrance of dye to internal membrane domains. Neither perfluorinated fatty acid molecule reduces the ability of surface immunoglobulin to migrate laterally and cap on cells. Our data suggest that perfluorinated fatty acids either interact directly with lipid binding sites for MC540, and thereby inhibit dye intercalation, or alter membrane lipid architecture and lipid packing to diminish MC540 binding. Both possibilities support a direct, physical, membrane‐altering mechanism for perfluorinated fatty acid toxicity on mammalian cells.

ISSN:0098-4108    

DOI:10.1080/15287398709530983

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

INDOOR AIR AND HUMAN HEALTH. Proceedings of Seventh Life Sciences Symposium held in Knoxville, Tennessee, October 1984. Edited byRichard B. GammageandStephen V. Kaye, Lewis Publishers, Chelsea, Michigan, 1985, 430 pp., $39.00.

ISSN:0098-4108    

DOI:10.1080/15287398709530984

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor