Showing papers in "Toxicology and Applied Pharmacology in 1998"

TL;DR: Findings from in vitro and in vivo studies which confirm that a range of alkyl hydroxy benzoate preservatives (parabens) are weakly estrogenic are reported, suggesting that the safety in use of these chemicals should be reassessed.

TL;DR: The protection against APAP toxicity afforded by deletion of both CYP2E1 and CYP1A2 likely reflects greatly diminished production of the toxic electrophile, NAPQI.

TL;DR: The data demonstrate that apoptosis is a major mode of elimination of critically damaged cells in acute Cd hepatotoxicity in the mouse, and it precedes necrosis.

TL;DR: It is conclusively demonstrated that CYP2E1 is the major factor involved in the CCl4-induced hepatotoxicity in mice.

TL;DR: The results suggest that delta-ALA-D from liver, kidney, and brain is a potential molecular target for the toxic effect of organic forms of selenium and tellurium.

TL;DR: Compared to adults, PND17 rats show similar behavioral changes and ChE inhibition although at a five-fold lower dose; the onset of maximal effects is somewhat delayed in the young rats; young rats appear to have more extensive muscarinic receptor down-regulation, and young rats show no gender-related differences.

TL;DR: The results demonstrate that the HepG2 assay is a sensitive and specific method for detecting chemical interaction with the androgen receptor, and should be useful for determining the role of multiple steroid receptors in the mechanism of action of endocrine active chemicals.

TL;DR: The effects of low doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the reproductive system of male offspring rats were examined and the male rats of the TCDD groups showed an increased number of abnormal sperm when investigated at adulthood.

TL;DR: A broad range of biopersistences for 19 different SVFs and 2 asbestos types is demonstrated; in contrast to several previous studies, fibers that dissolve relatively slowly in vitro at pH 7.4 are examined.

TL;DR: Inhibition of the first step of sphingolipid biosynthesis with ISP-1 prevented the elevation in sphinganine, DNA fragmentation, and apoptosis induced by FB1, and these effects of FB1 on HT29 cells can be attributed to the accumulation of sphedanine.

TL;DR: It is suggested that chlorpyrifos can interact directly with developing neural cells to inhibit replication and neuritic outgrowth and could be blocked by nicotinic or muscarinic antagonists, confirming that the effects were not mediated primarily through cholinergic hyperstimulation consequent to cholinesterase inhibition or to direct receptor-mediated effects.

TL;DR: The data indicate that relatively low levels of MEHP disrupt Sertoli cell-gonocyte physical interactions and suppress SERToli cell proliferation in neonates via mechanisms specific to neonatal testis where the foundations of adult fertility are established and highlight the neonatal period of testicular development as one particularly sensitive to environmental chemicals.

TL;DR: The results suggest that aberrant programmed cell death may be a suitable marker for exposure of feral organisms to dioxin-like compounds.

TL;DR: This CYP2E1 regulatory polymorphism is sufficiently common to impact susceptibility to CYP 2E1-related diseases in at least two ethnic groups.

TL;DR: Experiments using human cell line cells either expressing or not expressing human cytochrome P450 enzymes in assays of acute toxicity (MTT assays) have demonstrated a directly toxic potential of AFM1 in the absence of metabolic activation, in contrast to AFB1.

TL;DR: It is concluded that glial cells and TNF-alpha both modulate trimethyltin-induced neurodegeneration.

TL;DR: These studies indicate that, in addition to other inflammatory mediators and acute phase proteins, cytokines and chemokines are produced by hepatocytes, which may participate in hepatotoxic responses.

TL;DR: The fat-flush hypothesis provides a theoretical basis for a two-step model of organic pollutant transfer in the gastrointestinal tract, with absorption and excretion as distinct processes occurring at different locations.

TL;DR: It is demonstrated that PE are active in lactotroph cells of the pituitary, and the estrogenic effects of PE in PR1 cells were ER dependent, in that addition of the antiestrogen ICI-182,780 inhibited prolactin response.

TL;DR: Results indicate that myopathy was not induced by a secondary dysfunction of mitochondrial respiration due to low ubiquinone levels, and mitochondrial enzyme activities of respiratory chain were normal in all groups.

TL;DR: This study provides a scientific basis for interspecies extrapolation of nasal olfactory irritants from rodents to humans and suggests that the human ofactory epithelium is protected from irritating acidic vapors significantly better than rat olfaction due to substantive differences in nasal anatomy and nasal air flow.

TL;DR: It is demonstrated that (1) high doses of cisplatin produce hepatotoxicity, with apoptosis as the major lesion, and (2) MT protects against cisPlatin-induced liver injury.

TL;DR: Gender-related pharmacokinetic differences in the uptake and metabolism of trichloroethylene were minor, but apparent and the PBPK models for males and females consistently overpredicted exhaled breath concentrations of trICHloro methylene immediately following the TCE exposure for a 2- to 4-h period.

TL;DR: Results indicate that concentrations that altered Ca2+ disposition and second messenger systems in vitro are achievable in brain in vivo following repeated exposure to Aroclor 1254.

TL;DR: The results of this study suggest that inhibition data from mammalian studies could not be directly extrapolated to trout and likely other fish species and that care must be observed when mammalian P450 inhibitors are used to determine the participation of P450s in the metabolism and toxicity of xenobiotics in nonmammalian species.

TL;DR: The specific activity of this critical enzyme for arsenite biotransformation was determined by incubating liver, testis, kidney, or lung cytosol of male B6C3F1 mice with sodium arsenite and S-[methyl-3H]adenosyl-L-methionine and measuring the formation of [methyl- 3H]monomethylarsonate.

TL;DR: The IPPSF system appears to be a good model for predicting percutaneous absorption relative to man and should be used to validate other systems to humans in vivo.

TL;DR: A synergistic effect of I3C and crambene was evident on induction of GST and QR, but not on GSH, G-Rd, or P4501A; GSH levels were not elevated.

TL;DR: Data show clearly that IC50 values from a crude homogenate do not measure the true sensitivity of AChE to the inhibitor, and the "apparent" sensitivity of AChe was prone to vary dramatically with age and tissue type.

TL;DR: T-2 toxin-induced thymic atrophy is associated with cell death through a mechanism of apoptosis, and neither endogenous glucocorticoid nor TNF-alpha appeared to be involved in the apoptotic process.