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Biomedical subjects

R L Engle

Publications and source records attributed to R L Engle.

At least 19 recordsLinked to original sources
PubMed1992

Attempts to use computers as diagnostic aids in medical decision making: a thirty-year experience.

For more than 30 years our group of physicians, statisticians, and computer scientists has worked toward developing a computer program with the capability of a trained physician to make diagnostic decisions in the relatively broad medical subspecialty of hematology. We devised and tested many programs, none of which have been sufficiently useful to warrant carrying beyond the pilot-study stage. We analyzed the reasons for this failure. Our experience confirms the great difficulty, and even the impossibility, of incorporating the complexity of human thought into a system that can be handled by a computer. We concluded that we should stop trying to make a computer act like a diagnostician and concentrate instead on ways of making computer-generated relevant information available to physicians as they make decisions.

Algorithms↗
PubMed1983

Risk factors for breast cancer.

Since 1976, data were collected to evaluate risk factors for breast cancer in a hospital-based case-control study of 1185 women with breast cancer and 3227 controls. The risk of breast cancer increased with increasing age at first birth; this effect was not accounted for by parity. An early age at first birth appeared to reduce the risk relative to no pregnancy, whereas a late age at first birth was associated with a higher risk than not having a full-term pregnancy. High parity was associated with a reduction in the risk that was independent of that of age at first birth: for parity greater than or equal to 5, compared with parity 1-2, the relative risk estimate was 0.7 (95% confidence interval, 0.5-1.0). Late age at menarche was associated with a lower risk among premenopausal women but not among postmenopausal women. The relative risk decreased with increasing obesity among premenopausal women. Among postmenopausal women, the risk was higher among those who were obese, but there was no evidence of a trend with increasing body mass index. Risk did not vary materially according to history of abortion when gravidity was controlled. Risk was lower among postmenopausal women than among premenopausal women of the same age and increased with increasing age at menopause; bilateral oophorectomy reduced the risk more than hysterectomy alone. A positive history of benign breast disease, a positive family history of breast cancer, Jewish religion, and 12 or more years of education were each independently associated with an increased risk of breast cancer.

Adult↗
PubMed1982

Epithelial ovarian cancer and combination oral contraceptives.

The risk of epithelial ovarian cancer in relation to the use of combination oral contraceptives was evaluated in a case-control study of women younger than 60 years. Combination oral contraceptives were used by 35 (26%) of 136 cases and 187 (35%) of 539 controls. The relative risk estimate for combination oral contraceptive use was 0.6 (95% confidence interval, 0.4 to 0.9). The reduction in risk appeared to persist for as long as ten years after use had ceased and to be greater for longer durations of use, but these results were not statistically significant. The findings were not explained by parity or by other identified potential confounding factors. The results suggest that the use of combination oral contraceptives protects against epithelial ovarian cancer.

Adult↗
PubMed1982

Breast cancer and alcoholic-beverage consumption.

The relation between breast cancer and alcoholic-beverage consumption was evaluated in a case-control study of 1152 women with breast cancer and two groups of control women-519 with endometrial or ovarian cancer, and 2702 with non-malignant disorders. The relative-risk estimate of breast cancer, with allowance for all potential distorting factors, for women who had ever drunk alcoholic beverages relative to those who had never drunk was 1.4 (95% confidence interval, 1.0-2.0) when the comparison group was the group with endometrial or ovarian cancer and 1.9 (1.5-2.4) when the controls who had non-malignant disorders were the comparison group. The association was evident for beer, wine, and spirits. The association was not explained by any of the major known risk factors for breast cancer, but we had no information on dietary factors. The findings support the hypothesis that alcohol consumption, or related dietary factors, increases the risk of breast cancer.

Adult↗
PubMed1978

Evidence for structural homology between human red cell phosphoglycerate mutase and 2,3-bisphosphoglycerate synthase.

Previous reports have suggested the possibility of extensive structural homology between human erythrocyte bisphosphoglycerate synthase (glycerate-1,3-P2 leads to glycerate-2,3-P2) and phosphoglycerate mutase (glycerate-3-P in equilibrium glycerate-2-P). This study lends credence to that conjecture through comparative physicochemical investigations involving peptide mapping, circular dichroism, and immunological techniques. The data indicate that despite differences in function, both enzymes apparently manifest a high degree of similarity in primary, secondary, and tertiary structure. Mapping data also indicate that each protein is comprised of two apparently identical subunits.

Bisphosphoglycerate Mutase↗
PubMed1976

Histone interactions in solution and susceptibility to denaturation.

Histone interactions in solution may depend upon treatments used for purification. Optical rotatory dispersion and sedimentation-velocity measurements have been made in a reference solvent, before and after exposure to various treatments, to investigate histone susceptibility to irreversible denaturation. Some acid conditions and urea and guanidine solutions may denature. Interaction studies performed on nondenatured histones indicate that the dimer, (H4)(H3), and tetramer, (H4)2(H3)2, dissociate to monomers at low ionic strength. Sedimentation-velocity experiments suggest a model for the (H4)2(H3)2 tetramer, with a compact semispherical center and four protruding amino-terminal regions. Fractions H2a and H2b interact to form the mixed dimer in equilibrium with monomers. Fraction H2a self-associates readily to dimers, tetramers, and octamers, while fraction H1 associates only weakly to form dimers.

Acetates↗