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Biomedical subjects

R J Hardy

Publications and source records attributed to R J Hardy.

At least 91 records · Page 5Linked to original sources
PubMed1980

Normal patterns of human upper small bowel motor activity recorded by prolonged radiotelemetry.

In order to characterise human interdigestive cyclical motor activity, and its interruption by food, jejunal pressure changes in healthy volunteers were recorded continuously for 24 hours, using an ingested pressure-sensitive radiotelemetry capsule tethered at the duodenojejunal flexure. In 20 studies, the subjects fasted throughout; in another 20 studies they received a single standard meal. Using this technique, fasting motor complexes were easily detected. There was considerable variation in interdigestive cycle duration and in the interruption caused by food. The data were not normally distributed. The study indicates that any descriptions of 'atypical' jejunal motility patterns must take into account the wide variations seen in health, before they can be regarded as representing dysfunction or disease.

Adult↗
PubMed1980

A stochastic model for the occurrence of transient ischemic attacks.

This paper presents the development, application and evaluation of a stochastic model of the frequency of occurrence of transient ischemic attacks (TIAs). TIAs occur during periods of abnormal arterial activity. The TIAs which occur during a single period of abnormal activity are called a cluster of TIAs. Thus, the number of TIAs occurring in a time interval is determined by the number of clusters of TIAs occurring and the number of TIAs per cluster. The distribution of the number of clusters, which is a modification of the Poisson distribution, is obtained through the use of infinitesimal probabilities and the method of generating function. The number of TIAs per cluster follows the logarithmic series distribution. The distribution of the number of TIAs is then a modification of the negative binomial distribution, which allows for censoring of the data that may be related to the occurrence of the clusters of TIAs. Estimates for the parameters, based on observed frequencies, are obtained, which allow the model to be applied to data from the Aspirin in Transient Ischemic Attacks Study.

Aspirin↗
PubMed1980

Controlled trial of aspirin in cerebral ischemia.

The findings from a double-blind multicenter clinical trial of aspirin for treatment of cerebral ischemia are reviewed. Of 303 patients who had carotid transient ischemic attacks (TIAs), 125 were selected for carotid reconstructive surgery and were then randomly assigned treatment with aspirin or placebo. The remaining 178 patients were also randomly assigned to an aspirin or placebo regimen. Analysis of the first 6 months of follow-up showed a differential in favor of aspirin when death, nonfatal cerebral or retinal infarction and the occurrence of TIAs were grouped and considered together as end points. Restriction of end points to death or nonfatal cerebral or retinal infarction yielded no statistically significant differential between the aspirin and placebo groups. After these results were published, a study group from Canada reported that aspirin was effective in preventing threatened stroke, but that this effect was limited to males. Review of our nonsurgical group with respect to sex shows findings consistent with those of the Canadian study for the end points of stroke or death. Inclusion of the occurrence of TIAs in the group of end points, however, revealed that aspirin is effective in females as well as males.

Actuarial Analysis↗
PubMed1979

Evaluation of the relationship of sodium in drinking water and toxemia of pregnancy.

This study is a retrospective case comparison analysis of the relationship of water-borne Na+ and toxemia of pregnancy as a part of a continuous investigation at our facility on the role of various water constituents in human chronic disease. Five hundred thirty-seven toxemic pregnant women delivered at Jefferson Davis Hospital, Houston, Texas, during 1976 were matched by age, race, obstetrical history, and month of delivery to 537 non-toxemic controls. Sodium concentration in each patient's drinking water was derived, based on her address, from earlier prepared maps of sodium distribution in Houston's water supplies. Paired t-tests were performed to compare the Na+ levels, which varied from 19 to 250 mg/l in water supplies of cases and controls. Odds ratio analysis was used to test for the presence of a gradient in occurrence of toxemia in parallel with the gradient of Na+. No significant impact of water-borne Na+ in the indicated range was observed. Further studies incorporating still higher ranges are contemplated.

Evaluation Studies as Topic↗
PubMed1978

The effect of a reduction in leading causes of death: potential gains in life expectancy.

The potential gains in total expectation of life and in the working life ages among the United States population are examined when the three leading causes of death are totally or partially eliminated. The impressive gains theoretically achieved by total elimination do not hold up under the more realistic assumption of partial elimination or reduction. The number of years gained by a new-born child, with a 30 per cent reduction in major cardiovascular diseases would be 1.98 years, for malignant neoplasms 0.71 years, and for motor vehicle accidents 0.21 years. Application of the same reduction to the working ages, 15 to 70 years, results in a gain of 0.43, 0.26, and 0.14 years, respectively for the three leading causes of death. Even with a scientific break-through in combating these causes of death, it appears that future gains in life expectancies for the working ages will not be spectacular. The implication of the results in relation to the current debate on the national health care policy is noted.

Accidents, Traffic↗
PubMed1975

Driving of motor vehicles as a risk factor for acute herniated lumbar intervertebral disc.

In a case-control study of the epidemiology of acute herniated lumbar intervertebral disc in the New Haven, Connecticut, area, it was found that driving of motor vehicles was associated with an increased risk for developing this disease. It was estimated that men who spend half or more of their time on their job driving a motor vehicle are about three times as likely to develop an acute herniated lumbar disc as those who do not hold such jobs. Persons of either sex who said that they drove a car (either away from work or at work) were more likely to develop an acute herniated lumbar disc than those who did not drive at all. These associations between driving and acute herniated lumbar disc could not be attributed to any confounding variables considered in this study.

Acute Disease↗
PubMed1975

Pregnancy and the syndrome of herniated lumbar intervertebral disc; an epidemiological study.

In a study of the epidemiology of acute herniated lumbar intervertebral discs in the New Haven, Connecticut, area, it was found that the female cases had had more pregnancies resulting in live births than women of similar age without known herniated discs. However, cases had not had more pregnancies resulting in miscarriages than other women of their age. Among women who underwent surgery for their herniated discs, the association between number of live births and herniated discs was found for women with herniations at the L5 level but not for women with herniations at the L3 level.

Abortion, Spontaneous↗