The risks and benefits of taking aspirin during pregnancy.
Explore the source record for details and available documents.
Abnormalities, Drug-Induced↗
Biomedical subjects
K Hooper
Publications and source records attributed to K Hooper.
Ranking the carcinogenic hazards of occupational exposures: Exposure-Potency Index (EPI) values for nine volatile industrial chemicals.
Employers, employees, and occupational health professionals need a a simple index to rank carcinogens according to their potential danger at exposure levels which are commonly encountered in workplaces. We describe such an index, the Exposure-Potency Index (EPI). This simple proportion, dose level (mg/kg body weight/day) to which workers are permitted to be exposed/cancer-causing dose (mg/kg body weight/day) in test animals, permits comparisons among carcinogens. We have calculated this index for inhalation exposures to 1,3-butadiene, 1,2-dibromo-3-chloropropane (DBCP), 1,2-dibromoethane (EDB), ethylene oxide, formaldehyde, methylene chloride, propylene oxide, tetrachloroethylene (perchloroethylene), and trichloroethylene (TCE). The permitted worker exposure levels have frequently been close to the levels which induce tumors in laboratory animals. More recently, Permissible Exposure Limits (PEL's) for for some chemicals have been markedly reduced, and this is reflected in lowered EPI values. Combining EPI values with information on the numbers of exposed workers provides a simple means of identifying and ranking dangers to populations of workers.
Animals↗
Epigenetic carcinogens: problems with identification and risk estimation.
The mechanisms of carcinogenesis are just beginning to be understood. There is recent interest in the broad classification of carcinogens into two categories based upon their mechanism of action: those that interact with DNA via a genetic mechanism are termed genetic carcinogens; and those that do not directly interact with DNA, but may cause changes in DNA tertiary structure or methylation patterns, and are termed epigenetic carcinogens. Present knowledge is inadequate to justify separate risk assessment methods for genetic vs. epigenetic carcinogens. Quantitative estimates of carcinogenic risk are currently best made using non-threshold models.
Animals↗
The hazard evaluation system and information service: a physician's resource in toxicology and occupational medicine.
Hazard evaluation is an emerging science. The Hazard Evaluation System and Information Service (HESIS), part of California's program in preventive occupational health, is a resource for clinicians who wish to stay abreast of the relationship between toxicology and occupational health. For example, advances in assays for cancer or reproductive effects in test animals enable us to identify with greater confidence significant cancer or reproductive hazards among the increasing variety of workplace exposures. Occupational experiences with dibromochloropropane (DBCP), Kepone, bis(chloromethyl) ether, benzidine and vinyl chloride demonstrate the shortcomings of relying on human data. The latency period of cancer, limited sensitivity of epidemiologic studies and severity of effects require us to use animal test data to evaluate the potential cancer and reproductive risks of workplace substances. HESIS gives appropriate weight to experimental data in hazard evaluations of chemicals such as ethylene oxide, ethylene dibromide, polychlorinated biphenyls and the glycol ethers. A similar approach is apparent in the California Department of Health Services' recently released Carcinogen Identification Policy.
Abnormalities, Drug-Induced↗