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Biomedical subjects

C L Odoroff

Publications and source records attributed to C L Odoroff.

17 recordsLinked to original sources

Carcinogenicity of diethylstilbestrol in the Wistar rat: effect of postnatal oral contraceptive steroids.

Diethylstilbestrol (DES) has been associated with vaginal neoplasia and malformations in humans. We have studied a test population of 504 female Wistar rats given diethylstilbestrol at from 0.0 to 0.5 mg/kg maternal body weight on days 18, 19, and 20 of gestation. Animals were euthanized in extremis, or at 2 years of age. The incidence of vaginal epithelial tumors was dose related. The types of epithelial tumors of the vagina were adenocarcinoma, squamous cell carcinoma, and mixed carcinoma, containing discrete adenomatous and squamous components. The incidence of vaginal epithelial tumors was determined to be dose related: rats exposed to 0 mg DES/kg maternal weight had an incidence of 0.6% (1 of 167 rats); 0.1 mg/kg, 4.1%; and 0.5 mg/kg, 4.3% (6 of 140); 25 mg/kg, 1.6% (1 of 63); and 50 mg/kg, 11.5% (3 of 26). Tumors of other reproductive tissues (mammary gland, ovary, oviduct, cervix, or uterus) demonstrated no discernible DES dose-response relationship. There was no oncogenic effect of postnatal administration of oral contraceptives (0 oral contraceptives, 31.25 micrograms/kg diet ethynylestradiol, and 31.25 micrograms/kg diet norethindrone or 104 micrograms/kg diet ethynylestradiol and 31.25 micrograms/kg diet norethindrone). Thus, vaginal tumors can be induced in a dose-related manner in the rat following in utero DES exposure. Oral contraceptive treatment did not increase the risk of neoplasia.

Adenocarcinoma

Biplots in biomedical research.

The biplot is a graphical display of multivariate data. A number of examples from biomedical research illustrate its use. Biplots allow for inspection of data preliminary to formal analysis, and can follow an analysis by the graphical inspection of residuals. The simplicity and intuitive appeal of these displays is stressed. An appendix indicates their method of construction and the software for producing them.

Humans

The accuracy of blood glucose testing by children.

While studies have evaluated the accuracy of adult patients and health personnel in reading various glucose oxidase impregnated strips to estimate blood glucose, there are no studies exclusively evaluating the accuracy of children with diabetes reading their own strips as compared to a staff member, and meter to meter variability in reading these strips. We evaluated the accuracy of reading chemstrip bG by children at a summer camp. The children's visual readings of their own strips were compared to the visual reading of a single staff member. A total of 356 Chemstrip bG's were visually read by diabetic children and a single trained staff member at a summer camp for diabetics. The strips were then analyzed by two Accu-Chek bG meters. Intermachine variability was found to be negligible over the entire bG range. For the purposes of this study, we define accurate visual readings as those within +/- 15 percent of the meter reading of a given strip. At low bG values (40-79 mg/dl), accuracy by children and staff is low, with underestimating occurring in 39 percent of staff readings and 57 percent of children's readings. At intermediate bG values (120-239 mg/dl) readings are more accurate, especially when read by the staff, with misreadings occurring in only 16-19 percent of the strips. At high bG values (240-399 mg/dl), accuracy by children is decreased, with underestimation 500 percent more often than staff. We conclude that children are less accurate at reading Chemstrip bG than a trained staff member (51% versus 33% misreading), especially at the upper and lower ranges of bG values when visual readings are least accurate, and the need for therapeutic intervention is the greatest.

Adolescent

The mortality risk associated with digitalis treatment after myocardial infarction.

We examined the effects of digitalis therapy on postinfarction mortality throughout a 24-month to 48-month follow-up in 867 patients who survived an acute myocardial infarction. During follow-up, 145 patients died (16.7% mortality). At the time of hospital discharge, 31% of the patients were taking digitalis. The digitalis-treated patients were older, had more medical-cardiac risk factors, and had a higher mortality rate throughout the follow-up than the nondigitalis-treated patients. Statistical techniques were used to adjust for clinical imbalances between the digitalis-treated patients and nondigitalis-treated patients. The survival analysis (n = 728 patients) utilized the Cox regression model, and the digitalis-associated mortality risk was identified only after all significant covariates were allowed, so that mortality could be predicted as accurately as possible. Digitalis therapy was associated with a significantly increased postinfarction mortality risk after adjustment for the predictor covariates (relative risk 2.3, 95% confidence interval 1.4-3.7, p less than 0.001). The findings from this large multicenter study suggest that it would be prudent to exercise caution in the use of digitalis in postinfarction patients.

Aged

Infant mortality and economic instability in Yugoslavia.

Efforts to manage Yugoslavia's debt crisis beginning in 1979 led to economic policies which resulted in declining real income in subsequent years. This has been associated with a slowing of the rate at which infant mortality has declined. There is no evidence, however, that populations in poor parts of the country experienced a more dramatic impact on infant mortality than did populations in more favored regions. The lack of difference is attributed to redistributive social policies among and within republics.

Economics

Intercapillary distance and capillary reserve in hypertrophied rat hearts beating in situ.

Functional intercapillary distance (ICD) was measured in stop-motion photomicrographs of hypertrophied, normally compensated, well oxygenated rat hearts beating in situ. Left ventricular hypertrophy was produced by salt loading and unilateral nephrectomy. Minimum ICD (when all capillaries are open) also was measured. Ventricular weight increased by 30-40% within 8-9 weeks after nephrectomy. To compare the effect of normal and pathological growth, ICD was also measured in normal rats. In normal animals, minimum ICD and functional ICD increased linearly and proportionately with left ventricular weight. Consequently, the extent to which capillary recruitment could decrease ICD was the same in large and small normal hearts (about 2 micrometer). In the hypertrophied hearts, capillary recruitment could have maintained ICD within normal limits at rest for several weeks. After 8-9 weeks, however, the capillary reserve in hypertrophy was fully utilized at rest, and mean functional ICD was 1.5-2.0 micrometer greater than normal for the age of the animal. An analysis of O2 transport indicates that anoxic foci would exist throughout the hypertrophied heart and particularly in subendocardium when the capillary reserve is exhausted. The calculated amount of anoxic tissue appears sufficient to account for the focal necrosis and fibrosis observed in hypertrophy and for the development of circulatory failure.

Animals

Coronary intercapillary distance during growth: relation to PtO2 and aerobic capacity.

Intercapillary distance (ICD) was measured in left ventricles of rats beating in situ. Between 40 and 400 days of age, left ventricular weight increased threefold and ICD increased from 12.5-19.5 mum. ICD could be decreased by at least 2 mum at all ages studied. The number of capillaries which must be recruited to reduce ICD by 2 mum fell from 1,200/mm2 at 40 days to 280/mm2 at 400 days. Ventricular growth did not affect the O2 sensitivity of precapillary sphincters or the uniformity of capillary spacing. Calculations indicate that under basal conditions tissue PO2 (Pto2) in subepicardium is about the same at 40 and 400 days, even though VO2 per gram, capillary density, and ICD change twofold, twofold, and 7 mum, respectively. Nevertheless, as the ventricle grows, capillary recruitment becomes progressively less effective in defending Pto2 under conditions of stress. Diminished coronary capillary compensation for stress may, in part, account for the effect of age on the maximum aerobic capacity of the whole animal.

Aerobiosis

The use-effectiveness of two contraceptive methods in a Navajo population: the problem of program dropouts.

Navajo Indian intrauterine contraceptive device (IUD) and oral contraceptive users between 1966 and 1971 were followed up to estimate life table rates of complications and continuation. Because of high rates of dropping out, 41.6 per cent of 291 oral contraceptive users and 18.2 per cent of 534 IUD users, a 26 per cent sample survey of the dropout population was used to collate the dropout population data into the life table analysis. Estimates of the IUD continuation rates for one, two, and three years are similar to rates published elsewhere; however, continuation rates for the oral contraceptive are clearly lower than those for other populations, which only 33 per cent continuing after one year, 23 per cent after two years, and 12 per cent after three years. The IUD user is two to three times more successful than the oral contraceptive user in this population.

Adolescent