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Biomedical subjects

C Mahan

Publications and source records attributed to C Mahan.

8 recordsLinked to original sources
PubMed1989

Biochemical epidemiology of colon cancer: effect of types of dietary fiber on fecal mutagens, acid, and neutral sterols in healthy subjects.

Several epidemiological studies suggest an inverse relationship between fiber intake and colon cancer risk. Animal model studies indicate that this inhibitory effect depends on the source of dietary fiber. Because of the potential significance of certain colonic mutagens and secondary bile acids in the pathogenesis of colon cancer, the effect of types of supplemental fiber on fecal mutagens and bile acids was studied in human volunteers. Seventy-two healthy individuals consuming high-fat/moderately low-fiber diets were screened for fecal mutagenic activity using the Ames Salmonella typhimurium/microsomal assay system. Twenty-one of them were found to excrete high levels of mutagens, and 19 of them were recruited for the diet intervention study. All participants provided two 24-h stool specimens and a 4-day food record while consuming their normal (control) diet. They were then asked to consume the control diet plus 10 g of dietary fiber from wheat bran, oat fiber, or cellulose for 5 wk. After each fiber period, they were asked to consume their control diet. At the end of each fiber and control diet period, each subject provided two 24-h stool specimens. Stool samples were analyzed for bile acids and mutagens using the Ames strains TA98 and TA100 with or without S9 (microsomal) activation. The concentrations of fecal secondary bile acids (deoxycholic acid, lithocholic acid, and 12-ketolithocholic acid) and of fecal mutagenic activity in TA98 and TA100 with and without S9 activation were significantly lower during the wheat bran and cellulose supplementation periods. Oat fiber supplementation had no such effect on these fecal constituents. Thus, the increased fiber intake in the form of wheat bran or cellulose may reduce the production and/or excretion of mutagens in the stools and decrease the concentration of fecal secondary bile acids in humans.

Bile Acids and Salts↗
PubMed1989

Health policy brief: obstetrics in nonmetropolitan Oklahoma.

This brief is a summary of a 68-page analysis of a survey conducted by the Center for Health Policy Research, Oklahoma Medical Research Foundation, Tulsa. There are 9 appendices and 96 data analysis tables in the complete analysis. The survey was conducted in the summer and fall of 1988. Survey instruments were mailed to all Oklahoma obstetricians and family and general practitioners not practicing in Tulsa or Oklahoma counties. There were 300 responses, 274 of which were validated for inclusion into the study. The complete survey will be of interest to some institutions and groups and is available upon request. Customized analysis of the survey variables also is available to interested parties upon request.

Fees, Medical↗