Showing papers in "Toxicology and Applied Pharmacology in 1991"

TL;DR: PCBs congeners decrease cell dopamine content by interaction at specific sites that have preference for ortho- or ortho-, para-substituted congeners, and experiments with 2,2'-dichlorobiphenyl indicated that PCBs and not their metabolites were the toxicants.

TL;DR: Chemicals that produce oxidative stress by one of four distinct mechanisms are very effective at increasing MT concentrations in a variety of organs, suggesting that MT might be involved in protecting against oxidative stress.

TL;DR: In this article, the authors describe the cellular response to DMAA in the mouse lung and show that the mouse pulmonary cell produced active oxygens and peroxyl radical produced in the metabolism of DMAA.

TL;DR: Surprisingly, Cd2+, Co2+, Ni2+, and Zn2+, which caused a depression in hCG- and db-cAMP-stimulated T production, caused significant increases in HCHOL- and PREG- stimulated T production over untreated and similarly stimulated cultures, indicating that these cations may act at multiple sites within the Leydig cell.

TL;DR: It is confirmed that the conversion rate of acrylamide to glycidamide, as determined from hemoglobin adduct formation, is higher at low-administered doses, and dose-rate effects may significantly affect risk estimates of this compound.

TL;DR: Kinetic analysis showed that verapamil decreased the Vmax of cadmium uptake, without altering the Km, indicating a noncompetitive inhibition, and data suggest that about a third of the Cadmium enters hepatocytes through the calcium channels.

TL;DR: The relationship between mitochondrialCa2+ transport and the formation of superoxide suggests that a disruption in mitochondrial Ca2+ homeostasis by doxorubicin may be involved in the release of reactive oxygen species and its cardiotoxicity.

TL;DR: Regional and cellular localization of reduced glutathione in central and peripheral nervous tissue was determined from the pattern of fluorescence observed in tissue sections stained with mercury orange, and localization was confirmed using a novel histofluorochromatic staining method, o-phthaldialdehyde (OPT).

TL;DR: The toxicokinetics of permethrin after single 460mg/kg oral and 46 mg/kg intravenous doses were studied in male Sprague-Dawley rats, suggesting that a combination of metabolism by the tissues and diffusion into it from the blood may be present.

TL;DR: A physiologically based pharmacokinetic (PB-PK) model which describes the kinetics of CO, carboxyhemoglobin (HbCO), and parent dihalomethane, and has applied this model to examine the inhalation kinetic patterns of CO and of DCM in rats and humans is developed.

TL;DR: Inhibition of hepatotoxicity due to exposure to P450IIE1 substrates, CCl4 and NDMA, by DAS was observed under a variety of treatment schedules, and the starvation-induced microsomal P450 IIE1 level was decreased by D AS.

TL;DR: It is demonstrated that P450IIE1 was inhibited and inactivated by disulfiram, and this mechanism can account for many of the reported inhibitory actions of disulfIRam against chemically induced toxicity and carcinogenesis.

TL;DR: Investigating cell proliferation rates in the nasal epithelium of rats exposed to formaldehyde for a longer duration demonstrated a clear correlation between sites of cellular injury and increases in cell proliferation and a concentration-dependent response which correlated with the previously published formaldehyde bioassay tumor response.

TL;DR: This study further supports that disturbances of the cholinergic system during rapid development in the neonatal mouse can lead to permanent changes in cholinergic and behavioral variables in the animals as adults.

TL;DR: The results of this study indicate that the DNA double helix contains at least two kinds of binding sites for copper, one of which is present once every four nucleotides, has high affinity, and shows a cooperative effect.

TL;DR: These studies support the proposal that nasal airflow patterns play an important role in the distribution of lesions induced by formaldehyde, and a classification for the major airways in the nasal passages of rats and rhesus monkeys was proposed.

TL;DR: A review of features of bone structure and bone growth critical to the development of a physiologically based model of the whole-body kinetics of bone-seeking elements is presented in this paper.

TL;DR: The distribution and exact cellular localization of mercury in the brain and upper cervical spinal cord of the adult male Wistar rat has been determined using the autometallographic silver-enhancement technique.

TL;DR: It is demonstrated that cyclopiazonic acid is a potent inhibitor of azide-insensitive, ATP-dependent, a23187-sensitive calcium uptake by the lysate of LLC-PK1 cells, consistent with the hypothesis that the endoplasmic reticulum calcium transport ATPase is a sensitive target for cyclop Diazonic acid in LLC- PK1 cells.

TL;DR: It is concluded that TCDD inhibits testicular steroidogenesis predominantly if not exclusively by inhibiting the mobilization of cholesterol to cytochrome P450scc, and that this inhibition occurs subsequent to cAMP formation.

TL;DR: Experimental results showed that Pb enhanced the AFC response and Ig production in the presence of antigen-specific T cell help, suggesting that P b enhances B cell differentiation by augmenting cognate help rather than by inducing a response to Pb-altered-self.

TL;DR: Phosphoramide mustard is responsible for CPA ovarian toxicity, and the greater potency of PMC and T4P compared to CPA is likely the result of these compounds bypassing important detoxification steps, therefore, more of the parent compound reaches the ovary as the toxic metabolite.

TL;DR: Although the PAs induced DNA cross-linking to varying degrees, cell viabilities for all treatment groups were greater than 90% as determined by trypan blue dye exclusion, and two structural determinants of biological activity appear to be the presence of both a macrocyclic necic acid ester and an alpha,beta-unsaturated ester function.

TL;DR: The results demonstrate that P450IA proteins are induced in many organs of fish exposed to environmental chemicals in the wild, with patterns of cellular localization like those seen in fish experimentally treated with known inducers.

TL;DR: It is demonstrated that nuclear Ca2+ accumulation and DNA fragmentation appear as early events that correlate directly with later cytotoxicity, which may contribute to acetaminophen-induced injury leading to cell death in vitro and necrosis in vivo.

TL;DR: The results indicate that Cd2+ has relatively specific damaging effects on the adhering and occluding junctions between LLC-PK1 cells and that these effects may involve the disruption of cytoskeletal actin filaments.

TL;DR: Zn-induced MT in rat primary hepatocyte cultures protects against Ag-, Co, Cu, Hg, Ni, Pb, and Zn- induced cytotoxicity, and appears to be due to the binding of metals to MT with a concomitant reduction of metal content in critical organelles and proteins.

TL;DR: It is demonstrated that short-term, high-dose inhalation exposures of silica produce effects similar to those previously observed using intratracheal instillation or chronic inhalation models, and lend support to this method as a reliable short- term bioassay for evaluating the pulmonary toxicity and mechanisms associated with exposures to new and untested materials.

TL;DR: The PB-PK model for TCE adequately described the uptake and clearance of TCE in male and female rats exposed to a single, constant concentration of T CE vapor, but failed to describe the uptake or clearance inmale and female mice exposure to a wide range TCE vapor concentrations.

TL;DR: The results indicate that protection from OPIDP is only one effect of PMSF because promotion of OPIDsP is also observed depending upon the sequence of dosing, which is always related to the doses of PM SF, which inhibit NTE.