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Biomedical subjects

E O'Brien

Publications and source records attributed to E O'Brien.

At least 235 records · Page 13Linked to original sources
PubMed1989

A double-blind evaluation of captopril in elderly hypertensives.

To establish the role of angiotensin converting enzyme inhibitors in the management of hypertension in the elderly, 16 patients were treated with captopril in a randomized double-blind placebo-controlled cross-over study. Clinic blood pressure, ambulatory blood pressure, renal function and mental performance, with emphasis on mood and psychological well-being, were assessed. Twelve patients, aged 73 (+/- 4.4) years, completed the study. The doses of captopril used were 50 mg (11 patients) and 25 mg (one patient) twice daily for 4 weeks. Mean (+/- s.e.m.) clinic sitting blood pressure during captopril therapy was significantly lower than during administration of placebo (172 +/- 4.5/83 +/- 25 versus 188 +/- 4.4/89 +/- 3.4 mmHg; P less than 0.001/P less than 0.05). Mean ambulatory blood pressure was also significantly lower on captopril treatment than during administration of placebo (166 +/- 5.3/87 +/- 1.6 versus 179 +/- 5.1/94 +/- 2.4 mmHg; P less than 0.02/P less than 0.02) and this effect was sustained over the dosing interval. Renal blood flow and mental performance were unaltered by treatment. Gastrointestinal discomfort occurred in two patients, one of whom was withdrawn and cough developed in one patient. We conclude that captopril is effective as monotherapy in lowering blood pressure in the elderly.

Aged↗
PubMed1989

Discrepancy between clinic and ambulatory blood pressure measurement in the evaluation of two antihypertensive agents.

Discrepancies between clinic and ambulatory BP measurements may be important in the assessment of antihypertensive drug efficacy. Trimazosin (50-200 mg twice daily) and propranolol (40-160 mg twice daily) were compared in 22 hypertensive subjects in a randomised double-blind cross-over study. Daytime ambulatory BP was measured with a non-invasive portable recorder (Remler M2000). Clinic BP measurements were made with a random zero sphygmomanometer. While both drugs reduced clinic supine BP (trimazosin by 16/10 mmHg, P less than 0.01/P less than 0.001; propranolol by 25/14 mmHg, P less than 0.001/P less than 0.001), equivalent decreases on ambulatory measurement occurred with propranolol (28/11 mm/Hg, P less than 0.001/P less than 0.001) but not trimazosin (8/3 mmHg, P less than 0.05/NS). This difference in drug efficacy persisted throughout the 12-hour dosing interval. We conclude that clinic BP measurements alone cannot be relied upon to reflect accurately changes in BP induced by antihypertensive drugs. Moreover this study confirms the necessity for ambulatory BP measurement in the evaluation of antihypertensive drugs.

Ambulatory Care↗
PubMed1989

The need for a standardized protocol for validating non-invasive ambulatory blood pressure measuring devices.

Increasing interest in ambulatory blood pressure measurement has resulted in the proliferation of non-invasive measurement systems. This paper discusses the problems associated with validation of these systems. There is an urgent requirement for a standardized protocol for validation of ambulatory systems which is practicable, universally applicable and which is acceptable to investigators, publishing houses and the manufacturing industry.

Blood Pressure Determination↗
PubMed1988

Inbreeding and genetic disease in Sottunga, Finland.

The contribution of inbreeding to the prevalence of recessive genetic diseases in the Aland Island parish of Sottunga is investigated. Genealogical data for 3,030 individuals spanning up to 15 generations were used to estimate inbreeding. This small island community shows a low average inbreeding value of .0031 for the period 1725-1975. A cohort analysis shows that inbreeding increased from 1750 to 1900, when maximum inbreeding for those born in Sottunga reached .0057. A sharp decline in inbreeding occurred thereafter. Individuals with island-born parents made the largest contributions to inbreeding in all time periods compared to those with one or two migrant parents. These trends are consistent with changing migration patterns and isolate breakdown in Aland since 1900. An analysis of pedigree development demonstrates that remote consanguinity contributed more to inbreeding through time than close consanguinity. Both the number of common ancestors and the number of paths of relationship between spouses increased dramatically through time, the latter at a much faster rate. The contribution to average inbreeding per path, however, diminished rapidly through time. This analysis indicates that inbreeding does not account for the high incidence of autosomal recessive disorders, such as tapetoretinal disease, found in the parish.

Consanguinity↗
PubMed1988

Founder effect and genetic disease in Sottunga, Finland.

Pedigree data are analyzed in order to determine the factors responsible for the high frequencies of certain genetic disorders in an isolated Swedish-speaking population of Finland's A land archipelago. The founders of Sottunga are identified, and the genetic contributions of each founder to descending birth cohorts are estimated. Founders born before 1700 have far more descendants in the contemporary gene pool than do more recent founders. However, because of migration and depopulation since 1900, the expected genetic contributions of the early founders to the present-day population are similar to those of later founders. A descendant in the contemporary population has a 2% chance of having inherited a particular gene from the founder who makes the largest single contribution to the gene pool. This corresponds approximately to a 2% probability of inheriting an autosomal dominant disease gene from this founder. Given an average inbreeding coefficient of 0.0016, the probability of inheriting two recessive disease genes from this founder is 0.000032. The incidence of autosomal dominant von Willebrand disease in Sottunga is greater than 10% while that of autosomal recessive tapetoretinal disease is 1.5%. We conclude, therefore, that the high frequencies of these diseases are not due to the disproportionate genetic contribution of one or a few particular founders. It is more likely that these disease genes occurred in high frequency in the initial population or were introduced repeatedly through time.

Finland↗
PubMed1988

Cesarean birth rate: small-geographic-area analysis.

Population-based analysis of cesarean section rates within 172 geographic areas in the Commonwealth of Massachusetts during fiscal year 1985 revealed a nearly normal distribution of observed-to-expected rates, implying that the forces that compel obstetricians to perform this surgical procedure are pervasive. However, a small number of areas were identified in which the number of procedures performed was significantly different from the state mean. During fiscal years 1982 to 1985, certain geographic subgroups consistently demonstrated incidence rates significantly greater than the state mean. Although variation (either overutilization or underutilization) from the state rate is not synonymous with inappropriate care, those physicians within the identified geographic areas must take responsibility for ascertaining the explanation for the variance.

Cesarean Section↗
PubMed1988

HLA sharing and fertility in Hutterite couples: evidence for prenatal selection against compatible fetuses.

Antigenic differences between mother and fetus (i.e., blood group incompatibilities) were traditionally considered deleterious for viviparous reproduction. Recently, evidence has accumulated suggesting that maternal response to paternally derived fetal antigens, paradoxically, may facilitate maintenance of pregnancy. Thus, fetuses whose paternally derived antigens do not differ from maternal antigens (i.e., histocompatible pregnancies) may be at a selective disadvantage during pregnancy. Parents sharing histocompatibility antigens (i.e., HLA) may produce compatible fetuses and show overall reduced fertility. Indeed, increased HLA sharing has been reported in some couples experiencing repetitive spontaneous abortion. However, the effects of HLA sharing in couples not selected because of previous pregnancy losses have not been assessed. To elucidate the reproductive effects of maternal-fetal histocompatibility, we initiated prospective population-based studies of parental HLA sharing and reproductive outcome in the Hutterites, a population isolate that lives communally and proscribes contraception. The relationship between HLA-A, -B, and -DR sharing and reproductive outcome was examined in 111 Hutterite couples. Intervals from marriage to each birth were no longer among couples sharing antigens; differences were significant at the second birth and remained significant through the sixth birth (P less than .05). When the effects of sharing at individual loci were examined, HLA-DR was the only individual locus that was a significant predictor of birth interval length (P = .025). Completed family sizes were 6.5 and 9.0 among couples sharing and not sharing HLA-DR, respectively (P = .082, 2-tailed). However, recognized fetal loss rates did not differ among couples sharing and not sharing antigens.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Habitual↗
PubMed1987

Localization of neuropeptide Y mRNA in neurons of human cerebral cortex by means of in situ hybridization with a complementary RNA probe.

The distribution of mRNA encoding neuropeptide Y (NPY) in neurons of the normal human cerebral cortex in surgical biopsy specimens and postmortem brain was studied by in situ hybridization techniques. A 32P-labeled complementary RNA (cRNA) probe was used on cryostat sections of 13 formaldehyde-fixed cortical biopsy specimens. Hybridization to NPY mRNA was found in all samples: after autoradiography, discrete deposits of silver granules were observed on neuronal cell bodies abundantly distributed in the deep layers of the cortex, particularly laminae IV and VI, and on smaller cell bodies in the white matter. The localization of the neurons hybridized for NPY mRNA was comparable to that of NPY-immunoreactive cells as shown in sections from the same tissue blocks immunostained by using NPY antibodies. The specificity of the in situ hybridization technique was confirmed by blot hybridization analysis of electrophoretically fractionated RNA. This study clearly demonstrated the consistent localization of NPY gene transcription and expression in normal mature human cortical neurons.

Antibodies↗