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Biomedical subjects

S Rich

Publications and source records attributed to S Rich.

At least 145 records · Page 8Linked to original sources
PubMed1982

HLA and susceptibility to type I diabetes. Hypothesis.

Positive associations between the antigens D(R)3 and D(R)4 and negative associations of D(R)2 have been reported with insulin dependent or type I diabetes mellitus. It has been suggested that susceptibility factor(s) associated with the D(R)3 and D(R)4 haplotypes and a resistance factor associated with the D(R)2 haplotype may be involved in the pathogenesis of the disease. We propose a hypothesis herein which attempts to unify these findings based on our present understanding suggesting (a) the existence of multiple antigenic determinants associated with any one D(R) haplotype and (b) the sharing of "single" D region encoded determinants between what we now refer to as different D(R) haplotypes. The hypothesis, in its simplest form, focuses on a single D region determinant which can be found associated at different frequencies with the various D haplotypes as potentially explaining the findings.

Diabetes Mellitus↗
PubMed1982

Captopril as treatment for patients with pulmonary hypertension. Problem of variability in assessing chronic drug treatment.

We gave captopril, an angiotensin converting-enzyme inhibitor, to four patients with unexplained pulmonary hypertension to see if it would lower pulmonary arterial pressure or pulmonary vascular resistance. The patients were studied at rest and during supine bicycle exercise, before and after 48 hours of captopril treatment (up to 450 mg/day). During the treatment, each patient was monitored, with systemic and pulmonary pressures measured hourly, and cardiac output every two to four hours. We found no significant effect of captopril, either at rest or with exercise, on the cardiac output, pulmonary artery pressure, or pulmonary vascular resistance, measured at the end of 48 hours treatment. We noted, however, that during the 48 hour period, all patients showed pronounced swings in their pulmonary and systemic artery pressures and cardiac outputs that had no relation to the administration of captopril or time of day. We conclude that captopril appears to be ineffective in causing a sustained reduction in the pulmonary artery pressure or pulmonary vascular resistance in patients with primary pulmonary hypertension. It appears, however, that these patients experience spontaneous variability in their pulmonary resistance from hour to hour which needs to be further studied before a reliable assessment of long-term drug treatment can be made.

Adult↗
PubMed1982

Reduced training duration effects on aerobic power, endurance, and cardiac growth.

Thirteen subjects participated in an exercise program of bicycling and running 40 min/day, 6 days/wk. After 10 wk they continued to train either 26 of 13 min/day for an additional 15 wk. Intensity and frequency for the additional 15 wk remained the same as the last 3 wk of training. This study was undertaken to gain further insights into whether the increases in maximum uptake (VO2 max), endurance, and cardiac size can be maintained with reduced training durations. The average increases in VO2 max in response to 10 wk training were between 10 and 20% during the bicycle and treadmill testing. After reduced training, VO2 max continued to remain at the training levels in both groups. Short-term endurance (approx 5 min) was also maintained by both groups. Long-term endurance (2 h or more) remained the same in the 26-min group but decreased significantly (10%, 139-123 min) in the 13-min group. Calculated left ventricular mass increased 15-20% after training and remained elevated after reduced training in both groups. We conclude that it is possible to maintain almost all of the performance increases with up to a two-thirds reduction of training duration. Nevertheless, the data provide initial evidence that all aspects of the endurance-trained state may not be regulated uniformly in reduced training, particularly since VO2 max and short-term endurance were maintained, but long-term endurance decreased in the 13-min group.

Adult↗
PubMed1982

Linkage disequilibrium between insulin-dependent diabetes and the Kidd blood group Jkb allele.

We studied 102 randomly ascertained probands from the Upper Midwest United States with insulin-dependent diabetes mellitus (IDDM) with respect to both HLA-DR and Kidd (Jk) markers. Based on our evidence that multiple genetic mechanisms may be involved in the etiology of IDDM the data were partitioned according to the HLA-DR phenotype, containing either two high risk antigens (DR3 or DR4) or not. Probands with two such antigens showed no applicable deviation from control frequencies, while the remainder displayed a slightly reduced relative risk for Jka (RR = 0.70, p less than .25), but a significantly elevated risk for Jkb (RR = 2.53, p less than .025). These results strongly suggest a complex model of IDDM inheritance involving, at least, one susceptibility locus in linkage disequilibrium with HLA DR3 and DR4 on chromosome 6, and a second locus in linkage disequilibrium with Jkb on chromosome 2.

Adolescent↗
PubMed1981

Clinical assessment of heart chamber size and valve motion during cardiopulmonary resuscitation by two-dimensional echocardiography.

It has been generally accepted that enhanced blood flow during closed-chest CPR is generated from compression of the heart between the sternum and the spine. To visualize the heart during closed-chest massage, we performed two-dimensional echocardiography (2DE) during resuscitation efforts in four patients who had cardiac arrest. 2DE analysis showed that (1) the LV internal dimensions did not change appreciably with chest compression; (2) the mitral and aortic valves were open simultaneously during the compression phase; (3) blood flow into the right heart, as evidenced by saline bubble contrast, occurred during the relaxation phase; and (4) compression of the right ventricle and LA occurred in varying amounts in all patients. We conclude that stroke volume from the heart during CPR does not result from compression of the LV. Rather, CPR-induced improved cardiocirculatory dynamics appear to be principally the result of changes in intrathoracic pressure created by sternal compression.

Aged↗
PubMed1981

Lesion distribution, multiple infection, and the logistic increase of plant disease.

The lesions of few of the 112 observed cases of plant disease were randomly distributed; most were fitted by the negative binomial function with exponent approximately 1. The proportion of healthy hosts generally equaled the frequency of zero in the negative binomial. The same course of an epidemic is calculated for the logistic increase of infected plants or for plants infected by propagules produced in proportion to lesions and distributed with exponent equal 1.

Journal Article↗
PubMed1981

Clotted false lumen: reappraisal of indications for medical management of acute aortic dissection.

Evidence of a clotted false lumen in patients with acute aortic dissection has been considered to be a primary indication for medical rather than surgical therapy. A review of recent publications shows that 14 of 15 such patients survived with medical management. We present three patients who had radiographic, surgical, or necropsy evidence of acute aortic dissection with a clotted false lumen, who suffered further dissection in spite of adequate medical therapy. Our experience indicates that this condition is not as stable as it has been considered in the past. Consequently, we believe that great caution should be exercised in the application of medical therapy and in the follow-up of patients who demonstrate evidence of a clotted false lumen in an acute aortic dissection. Surgical treatment is indicated at the earliest sign of clinical or radiographic deterioration during medical therapy.

Acute Disease↗
PubMed1980

Percutaneous transluminal angioplasty. Nonsurgical therapy of occlusive arterial disease.

Percutaneous transluminal angioplasty offers the physician an alternative to surgical therapy of occlusive arterial disease in selected patients. Its current use in peripheral vascular disease has been successful and widely accepted. Application of the technique to stenosis of the renal and coronary arteries is still investigational and associated with considerable morbidity. Its usefulness in these situations will be determined by the outcome of further clinical trials.

Arterial Occlusive Diseases↗
PubMed1980

The angiographic effect of ergonovine and nifedipine in coronary artery spasm.

In a patient with variant angina, we have shown that the calcium-channel blocker nifedipine inhibits both spontaneous and ergonivine-induced coronary artery spasm. It had no effect, however, on the dose-related diffuse vasoconstriction caused by ergonovine, suggesting two distinct responses of coronary arteries to ergonovine provocation. Nifedipine did not cause epicardial coronary artery dilatation, as did nitroglycerin, supporting the rationale of using both therapies together to treat coronary artery spasm.

Adult↗
PubMed1979

Human chorionic gonadotropin and malignant mesothelioma.

A 56-year-old male presented with ascites and gynecomastia. Laparoscopy demonstrated peritoneal tumors which were biopsied. Conventional histology and electron microscopy revealed the tumor to be a malignant mesothelioma. The ascitic fluid and tumor cell lysate, but not serum, contained hCG by specific assay, and the immunoreactive hCG had characteristics similar to purified hCG in filtration on Sephadex G-100. Malignant mesothelioma is a tumor which may be associated with elevated hCG concentrations. Demonstration of hCG in ascitic fluid should suggest the presence of neoplasm.

Ascitic Fluid↗
PubMed1970

Ozone uptake by bean leaves.

The removal of ozone from the air by bean leaves is regulated by the same factors that control the exchange of water vapor between leaves and the atmosphere.

Air Pollution↗