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Biomedical subjects

M F Cranmer

Publications and source records attributed to M F Cranmer.

7 recordsLinked to original sources

Estimation of risks due to environmental carcinogenesis.

Several Federal agencies share responsibility for enforcing laws designed to control human exposures to carcinogens. This enforcement activity often has immense effects on other factors of our environment. Absolute safety is not possible, but increased protection is obtainable. Improvements are urgently needed in our ability not only to detect but also to quantify relative risk. Resources should be directed for maximum overall effect. Relative risk must be quantified if we are to reasonably compare risk and benefit. Examples of the inexactness of current toxicological, epidemiological, and mathematical models for estimating risk due to exposures to DDT, aflatoxinb1, DES, and benzidine are presented. The impact of different laws and regulations applicable to the control of these agents is compared. Reference is made to major programs in toxicological methods for risk estimation.

Aflatoxins

Effects of diphenylhydantoin and chloroquine on monkey liver microsomal mixed-function oxidases.

Sixteen adult male squirrel monkeys (Saimiri sciureus) were randomly divided into three treatment groups and one control group. Each treatment group received 10 mg/kg oral doses of diphenylhydantoin and/or chloroquine. Following sacrifice, in vitro assays for activity of liver microsomal mixed-function oxidases were run. The assays confirmed diphenylhydantoin as a potent inducer of mixed-function oxidases. Chloroquine administration had little affect on the enzymes assayed and did not inhibit the diphenylhydantoin induction.

Animals

Research data integrity: a result of an integrated information system.

The toxicologic problems of today frequently require long-term, multidisciplinary experimentation involving large numbers of animals. In order to provide the extensive safety evaluation necessary to produce data that can be reasonably extrapolated to humans, automated research support systems have transcended the position of useful tools and have become an integral part of the total design of experimental protocols. For an automated information system to fully represent the reality of the experiment, it must be able to assure integrity, as well as provide for the storage, calculation, and retrieval of data values of the quality and quantity necessary for fulfilling protocol requirements. Guarantees against error and loss of data, in addition to flexibility and easy access, must be an inherent part of the system if the acceptance and condifence of the investigator are to be obtained. This paper discusses the criteria, philosophies, and benefits of integrated data systems that ensure integrity of toxicologic research support.

Computers

Advances in animal care technology at the National Center for Toxicological Research.

The research purpose of the NCTR as it relates to animal care emphasizes the improvement of protocols for safety assessments, the study of irreversible lesions, and the use of valid animal models. The development, building, and operation of the "A" Barrier were described. The "A" Barrier is a complex of equipment, instrumentation, and rooms with controlled entry designed to prevent introduction of microoranisms or environmental factors into the SPF animal colonies. Support facilities such as computer controls and pathology were also described. The first experimental compound being tested is 2-acetylaminofluorene (2-AAF) which will be administered to a total of 25,000 mice in some 72 different treatment groups at 7 dose levels. The desired end-product of the center is to produce a series of tests which can be done quickly, efficiently, and economically and allow for a realistic estimate of risk to man of suspected toxic chemicals.

Animal Feed

Analysis of chlorinated insecticides and congeners.

A review on the state-of-the-art for analysis of chlorinated insecticides and their congeners is presented. Tables are included that show comparisons among gas chromatographic systems, high speed liquid chromatographic systems and sample preparation methods as well as an overview on sample cleanup.

Chromatography

NCTR computer systems designed for toxicologic experimentation. I. Overview.

Established in 1971 by the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA), the National Center for Toxicological Research is committed to the study of long-term, low-dose effects of potentially toxic substances, including carcinogens. The Scientific Information Systems Division (SISD) facility provides logistic support for complex experiments involving large numbers of test animals. Animal population at the Center, including the breeding colony and animals on experiment, can be as high as 80,000. Each animal must be accounted for, fed and watered under strict control, and continually observed. From birth to final examination, an individual animal might have as many as 3,000 individual elements of information associated with it. This paper introduces a series of reports dealing with an integrated and comprehensive system of experiment planning and implementation (including information gathering, classification, analyses and reporting), employing state-of-the-art data processing techniques. This extensive use of computer technology has permitted the collection, proper classification, and rapid retrieval of virtually error-free data, resulting in cost-sensitive experiment planning.

Computers