Showing papers in "Regulatory Toxicology and Pharmacology in 1989"

TL;DR: The adult study confirmed the validity of the tracer methodology to estimate soil ingestion and found the elevated estimates of soil ingestion by Ti were substantially reduced when food ingestion is considered.

TL;DR: An analysis of hepatic aflatoxin B1-DNA adduct concentrations in rats and trout demonstrated that the hepatic cancer risk was linearly and quantitatively related in both species, and provided a possible basis for the use of adduct measurements for estimating human cancer risk.

TL;DR: In this paper, an ambient water quality criterion for the protection of human health of 103 μg/liter is proposed for ingestion of drinking water and aquatic foodstuffs, and a criterion of 105 μg /liter for ingestion alone.

TL;DR: Pesticides monitored by state and federal agencies are compiled and the need for improvements in analytical techniques and enforcement procedures in governmental monitoring programs is pointed out.

TL;DR: A relative potency method for assessing potential human health effects from exposures to relatively untested chemicals is presented and documented and the need for such a method in evaluating the carcinogenic potential of the chemical warfare agent sulfur mustard from a limited data base is specifically addressed.

TL;DR: It was surprising that an IARC Working Group meeting in 1987 concluded that there was sufficient evidence to consider aflatoxin a probable human carcinogen, although the epidemiological studies of the HBV/PLC relation indicate that an accessory factor is not an essential condition.

TL;DR: Each of the four portions of risk assessment (hazard identification, dose-response assessment, exposure assessment, and risk characterization) has undergone significant refinement since 1985 and the net benefit should be a reduction in the uncertainty inherent in current estimates of the health risks posed by low level exposure to carcinogens and developmental toxicants.

TL;DR: Data from a recent EPA study of airborne asbestos levels in 49 buildings occupied by the General Services Administration (GSA) are statistically analyzed and no statistically significant differences were detected.

TL;DR: It is suggested that, particularly with nongenotoxic carcinogens, such studies may be of great use in risk assessment especially for those cases in which animals are exposed at very much higher levels of the test agent in the carcinogenesis bioassay than are humans as the result of the environmental or other use of the agent.

TL;DR: The control by the Food and Drug Administration of aflatoxin, a relatively recently discovered, unavoidable natural contaminant produced by specific molds that invade a number of basic food and feedstuffs, provides an example of the varying forces that affect risk assessment and management by a regulatory Agency.

TL;DR: In the case of 1,1,1-trichloroethane, the PBPK approach to interspecies and interroute extrapolation of toxicity data resulted in lower drinking water concentrations predicted to be nontoxic to humans than corresponding concentrations obtained using a traditional method for determining safe levels.

TL;DR: This methodology has provided for the specific PAHs a determination of proposed acceptable concentration levels quantitatively based on the same data that were used to qualitatively determine them to be animal carcinogens, and it is suggested that this methodology may be applicable to other classes of carcinogenic compounds.

TL;DR: More research is now being focused to better define the mechanisms by which the many distinctly different classes of nongenotoxic carcinogens are acting, which will become the basis for new predictive assays and more realistic risk assessment models.

TL;DR: There was no evidence that chlordane induced tumors in the ICR mice, and a long-term no-observed-effect level (NOEL) of 1 ppm Chlordane in the diet was found.

TL;DR: It is suggested that a quick estimate of the VSD could be obtained by dividing the MTD, obtained from a subchronic study, by 400,000, unless the human exposure is extremely low, which would mean the estimated risk is likely to be negligible even if the chemical is a carcinogen.

TL;DR: This paper represents an attempt to share the thought processes that have been used at the Food and Drug Administration to address the nonclinical pharmacology and toxicology study concerns.

TL;DR: Conventional carcinogenic potency estimates for chemicals have been compared across rodent species and would seem to provide little information on the actual human cancer risks from chemical exposure, thanks to the strong interspecies correlation and the small group sizes utilized.

TL;DR: The ability of both animal and human studies to detect small increases in tumor occurrence rates is evaluated in statistical terms and consideration is given to resolving apparent conflicts between the toxicological and the epidemiological sources of data.

TL;DR: The data were found to be sufficient to quantify human risk to acifluorfen, which produced benign and malignant liver tumors in male and female B6C3F1 mice and in female CD1 mice.

TL;DR: A workshop was organized to specifically define the assumptions underlying the risk assessments for seven specific toxicants and to determine the potential research which would reduce the uncertainty associated with making those assumptions.

TL;DR: Although certain relatively species-specific manifestations of developmental toxicity may at times be maternally mediated, most are not, and the margin of safety for exposure to a developmental toxicant is of much more importance than whether or not the agent's effects are maternALLY mediated.

TL;DR: Cancers of the Zymbal gland and the blood-forming system were selected as endpoints for the assessment because of their consistent occurrence and the amount metabolized/day as a result of exposures 5 days a week for a lifetime was judged to be an appropriate dose paradigm for this assessment.

TL;DR: In a previous paper (A.

TL;DR: Until biomedical research provides a satisfactory understanding of the complex mechanistic determinants of such diseases, epidemiology can only field reductionist causal hypotheses, leading to results of uncertain significance.

TL;DR: From the original pathologist the no-observed-effect level (NOEL) for chlordane in the diet of Fischer 344 rats was found to be 5 ppm and from the peer review data the NOEL in males is 25 ppm and in females is 1 ppm.

TL;DR: Estimates of teratogenic and carcinogenic risks for chemicals when both effects occur in the same animal species when a similar standard of risk is applied to both effects varied from an order of magnitude lower to an orders of magnitude higher for these nine chemicals.

TL;DR: Because of a misunderstanding of the limited scope of the analysis involved, the IARC and HHS lists have recently been used as a basis for legislative and regulatory decisions.

TL;DR: The major concepts of the immune system are presented by reviewing specific examples of immune responses and their environmental interactions and data from selected toxins are used to illustrate how these responses may be altered.

TL;DR: The position is taken that there are considerable limitations in the use of laboratory rodents in toxicological studies which purport to be meaningful with regard to prediction of toxicant-induced effects on ecological systems and an integrated plan is suggested that includes the systematic monitoring of native species in conjunction with laboratory animals exposed in the laboratory and in the field.