Showing papers in "Toxicology and Applied Pharmacology in 1987"

TL;DR: The PB-BK analysis suggests that conventional risk analyses greatly overestimate the risk in humans exposed to low concentrations of DCM, and PB-PK considerations provide a scientific basis for risk assessment, improve experimental design in chronic studies, and structure collection of quantitative metabolic constants required for risk Assessment.

TL;DR: DCA and TCA are complete hepatocarcinogens in B6C3F1 mice and are determined to act as tumor promoters in mouse liver.

TL;DR: The ability of the continuous breeding protocol to discriminate the qualitative and quantitative reproductive effects of the more and less active congeners as well as the large differences in reproductive toxicity attributable to subtle changes in the alkyl substitution of phthalate esters are demonstrated.

TL;DR: Phenol-induced stimulation of hydroquinone metabolism and benzoquinone formation represents a likely explanation for the bone marrow suppression associated with benzene toxicity.

TL;DR: A role for the Ah receptor in the down-regulation of uterine and hepatic ER levels in the female rat is supported and this effect may be associated with the decrease in spontaneous mammary and uterine tumors observed in female rats treated with 2,3,7,8-TCDD.

TL;DR: Results indicate that neurotoxic derivatives of alkylmetals studied increase [Ca2+]i, mainly either by nonspecific increase (Met-Hg, TET) of Ca2+ leakage through the plasma membrane and/or specific interference with the mechanisms regulating Ca2- fluxes through the Plasma membrane (TEL).

TL;DR: This study indicates that aldehyde dehydrogenase (ALDH) may participate in the in vivo metabolism of cytotoxic aldehydic products formed during lipid peroxidation.

TL;DR: It may be possible to use a flow-limited physiological pharmacokinetic model to describe the kinetics of in vivo cholinesterase inhibition by soman, and blood flow was the most important, accounting for 79% of the variation in the in vivo rate of cholinerase inhibition.

TL;DR: The data demonstrate that THC rapidly crosses the placenta and enters the fetus, and suggest that the fetus does not readily metabolize THC to 11-nor at this stage of development.

TL;DR: An association between peroxisome proliferation and hepatic tumors in mice following TCE and PER, but not PENT, administration is supported and it is suggested that chlorinated hydrocarbon-induced peroxISome proliferation does not correlate with species-specific renal carcinogenicity.

TL;DR: Saturation of overall metabolism in mice but not in rats at high doses by both routes of administration indicates species differences in metabolism of benzene.

TL;DR: Differences between the two species were observed in the levels of constitutive activities, the amount of induction, and in the regioselectivity of phenanthrene oxidation and androstenedione metabolism.

TL;DR: A comparative study of the effects of dietary butylated hydroxyanisole (BHA) on the hepatic in vivo DNA binding and in vitro biotransformation of AFB in the rat and mouse indicates that mice have high levels of an AFB-epoxide-specific GST activity relative to that of the rat.

TL;DR: The PB-PK model which was successful in describing the mixture data was used to predict conditions under which 1,1-DCE hepatotoxicity would be expected in coexposure to constant concentration atmospheres of these two chloroethylenes.

TL;DR: HBB inhibited estradiol 2-hydroxylase activity of purified cytochrome P-450d in a noncompetitive manner with an I50 of 38 nM for 50 nM P- 450d whereas its noncoplanar isomer, 2,4,5,2',4',5'-hexabromobiphenyl, had an I 50 over 700-fold higher.

TL;DR: The data suggest that olfactory mucosa may metabolize carboxylesters to acids more readily than respiratory mucosa, but such metabolism does not occur in the target cell population, the Olfactory sensory neurons, raising the possibility of intercellular migration of toxic acid metabolites.

TL;DR: These studies provide the first evidence for a reversible binding between a metabolite of TMP and a male-rat-specific protein in the kidney and thus provide important insight delineating a potential mechanism of hydrocarbon-induced hyaline-droplet nephropathy.

TL;DR: The results indicate that the low teratogenicity of 13-cis-retinoic acid in the mouse is the result of minimal placental transfer of this compound and of its 4-oxo metabolite, which contrast sharply with extensive placentalTransfer and high teratogenicicity of the corresponding isomers with the all-trans configuration.

TL;DR: Results indicate that the GSH-dependent oxidation of HCHO catalyzed by FDH is an important defense mechanism against the covalent reactions of H CHO with nucleic acids in the respiratory mucosa.

TL;DR: The GABAA receptor was desensitized as shown by the dose-dependent reduction in GABA-induced 36Cl-influx that resulted from preincubation of the membranes with GABA.

TL;DR: Human red blood cells incubated under nitrogen with methylene blue and glucose at physiological temperature and pH can be used to test for the biotransformation of nitrogenous vasodilators to nitric oxide (NO).

TL;DR: While the response of thyroid hormones to TCDD differed qualitatively, effective doses in hamsters were higher than in rats, suggesting that these changes, although secondary, may correlate more directly with toxicity than does enzyme induction.

TL;DR: This study supports previous reports implicating calcium as an intracellular mediator of cyanide toxicity and shows in a cell model that cyanide induces an accumulation of cytosolic Ca2+ and this additional cytosol Ca2+, appears to originate primarily from the extracellular compartment.

TL;DR: Results with all four anatomical models and various ventilatory parameters showed a qualitative similarity in the shape of the dose versus airway number curves but significant differences in predicted percentage total and percentage pulmonary uptake.

TL;DR: This study demonstrates the important role of liver GSH in the metabolism of inorganic arsenic in vivo and suggests that a drastic reduction of GSH level in liver not only impairs the methylation of in organic arsenic but also impairs its biliary excretion.

TL;DR: The lack of correlation between the inhibition of brain AChE by malaoxon and species-related differences in acute I D50 suggests that other factors, such as the limited carboxylesterase activity in fish, may be responsible for this species selectivity.

TL;DR: In this article, a single oral dose of [14C]TMP (4.4 mmol/kg; 2 microCi/mmol) was administered to male and female Fischer 344 rats and radiolabeled material in kidney, liver, and plasma was determined at 4, 8, 12, 24, and 48 hours after dosing.

TL;DR: The results suggest that the ability of TCDD to alter receptor coupling or the receptor number for diverse hormones may play a role in T CDD toxicity.

TL;DR: Changes in [3H]TCDD binding to unoccupied liver Ah receptor were examined following chronic or acute administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin to adult female Sprague-Dawley rats.

TL;DR: It is concluded that microtubule assembly alterations are not etiologic in the development of nervous system dysfunction following intoxication but may represent the biochemical mechanism of 2,5-HD-induced testicular atrophy.