Showing papers in "Regulatory Toxicology and Pharmacology in 1994"

TL;DR: Key aspects of the NRC/NAS report dealing with the use and replacement of default options and the extent to which the options are replaced with specific science have major impact on the final quantitation of cancer risk for exposure to chemicals.

TL;DR: Diethylnitrosamine (DENA) was the most potent and predictable hepatocarcinogen in cynomolgus, rhesus, and African green monkeys, and procarbazine was the only unequivocal carcinogen, with a 33% tumor incidence, causing acute nonlymphocytic leukemia in most of the cases.

TL;DR: A new approach to characterizing the state of knowledge about carcinogenic potency is described, whereby the carcinogenic risk posed by a specific dose is characterized by a probability distribution, indicating the relative likelihood of different risk estimates.

TL;DR: The surface-based extrapolation model for estimation of the human equivalent dose is not appropriate, and the carcinogenic potency factors for PrO as previously derived by the U.S. EPA should probably be revised downward.

TL;DR: The potential health effects of caffeine have been investigated for over two decades in a variety of model systems including limited human populations, and it is difficult to implicate caffeine, even at the highest levels of dietary consumption, as a genotoxin to humans.

TL;DR: The prime overall recommendation is that the NTP should move from a focus on hazard identification to an emphasis on providing the type of biological information that needs to be incorporated into the risk assessment process.

TL;DR: Interim results of a 5-year workplace monitoring program conducted by firms belonging to the Refractory Ceramic Fibers Coalition pursuant to a Consent Agreement with the U.S. EPA provide an interesting illustration of a successful cooperative effort between a responsible industry and regulatory agencies.

TL;DR: The overall results of 124 consecutive rodent carcinogenesis assays carried out at the maximum tolerated dose on 37 chemicals reported recently by the Toxicology Program of the United States showed tumor increases and decreases occurred in 31 experiments each.

TL;DR: Comparisons of the structural determinants associated with genotoxic effects with those associated with cell or systemic toxicity indicate extensive overlaps and can be taken to indicate that toxicity may contribute to genotoxicity.

TL;DR: The requisite basis for each of these factors and suggested methods for obtaining and evaluating the necessary data are presented and two example calculations are presented for setting ACD-based goals for hexavalent and trivalent chromium in chromite ore-processing residues.

TL;DR: The high-intensity sweetner, aspartame, is a food additive that has been the subject of extensive evaluation during the postmarketing period and is thus used as an example to discuss post marketing surveillance.

TL;DR: It was recognized that reduced protocols may not be appropriate for the testing of all chemicals and that additional analyses/data may be needed for selection of the most appropriate reduced protocol for certain chemicals/chemical classes.

TL;DR: It is concluded that benchmark doses for a 5% increases in incidence can be calculated for most datasets, and could be used as a satisfactory basis for risk assessment, e.g., to set reference doses or acceptable daily intakes.

TL;DR: A reevaluation of liver tumor diagnoses from seven PCB studies in rats shows major differences in carcinogenic potential based on degree of chlorination, indicating that continuation of a science policy of assuming that all PCBs are probable human carcinogens with a potency equivalent to the mixture that contains 60% chlorine has no scientific foundation and should be reconsidered.

TL;DR: This value may be viewed as conservative since it represents the 95% lower confidence limit on the dose associated with a 10% increase in response for a sensitive endpoint and has appropriate dosimetric adjustments and uncertainty factors incorporated.

TL;DR: The exposure level in the rat inhalation study was sufficiently, if not excessively, high in comparison to human exposures, which would not serve to mirror human environmental or occupational exposures.

TL;DR: The current unit risk for airborne arsenic, 4.29 x 10(-3), was established by the EPA in 1984, is likely to overestimate the effects of airborne arsenic by a factor of 3.3 based on updated results from a cohort mortality study on Tacoma smelter workers and recent findings from a cohorts study of 3619 Swedish smelters.

TL;DR: The paper proposes that the NOAEL be defined as the highest dosage tested that is statistically significantlyDifferent from the control group while also being statistically significantly different from the LOAEL.

TL;DR: There is a generally good agreement between various predictions and the actual carcinogenicity results, and a combination of two methods of prediction produces an over 80% concordance with the rodent bioassay.

TL;DR: The authors provide an overview of some of the more important features of TOS as they pertain to immunity and speculate on the immunopathologic mechanisms by which the TOS progressed, with emphasis on oxidative stress as a central byproduct of anilide-induced injury.

TL;DR: The ETS-lung cancer epidemiologic data do not support a causal inference or provide a scientific basis for government regulation of smoking in the workplace, and are supported by the results of 14 worldwide studies of lung cancer and ETS exposure in the workplaces, which in combination indicated no risk elevation.

TL;DR: The present paper discusses the Dutch method for carcinogenic risk assessment and concludes that this method for risk assessment is still a valid and appropriate one.

TL;DR: Although the molecular event(s) that translate fiber-induced cellular injury into a pathologic state are unknown, there is strong evidence in man and laboratory animals to suggest both dose dependency and thresholds for effects.

TL;DR: During almost three decades of experience with hydrophobic silicas, no adverse health effects have been observed in manufacturing and applications with appropriate handling of the materials.

TL;DR: The most recent of New York City's asbestos emergencies occurred in the late summer of 1993 and prevented schools from opening that fall, precipitated much media excitement, and caused a flurry of widespread abatement activities because much of EPA's policy lacked a scientific basis for risk evaluation and assessment.