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Biomedical subjects

R H Jones

Publications and source records attributed to R H Jones.

At least 307 records · Page 17Linked to original sources
PubMed1979

A measure of intensity of parental punishment.

To test the possibilities that antecedents and consequents of certain levels of intensity of punishment may have far-reaching effects on behavior, a self-report measure of parental intensity of punishment was developed. Consisting of 33 different situations to which parents react, scores from the instrument were found to be reliable over time. Further construct validity was demonstrated with a variety of predicted relationships between punishment intensity and parent and child characteristics. Five samples of subjects were used with over 400 families, high intensity of punishment scores were found to be related to mothers' lack of warmth and to her intrusiveness when playing with her child; children's maladjusted behavior; aggression and impulsivity in boys; withdrawal and inhibition in girls, and uncooperativeness. Inconsistency of parental punishment also was associated with maladjustment. Results were discussed in terms of Rotter's social learning theory.

Adolescent↗
PubMed1979

Noninvasive assessment of hemodynamic effects of mitral valve commissurotomy during rest and exercise in patients with mitral stenosis.

Noninvasive radionuclide angiocardiography (RNA) provides simple and accurate assessment of parameters of cardiac function during rest and during maximal exercise. Left ventricular function was assessed by RNA in nine patients with isolated mitral stenosis before and approximately 6 months after mitral commissurotomy. Before operation, the mean mitral valve gradient was 14.0 +/- 2.8 mm Hg, and the mean mitral valve area was 1.20 +/- 0.3 cm2. Each patient was evaluated at rest and during maximal exercise on an isokinetic bicycle ergometer before and after commissurotomy. Heart rate, ejection fraction, end-diastolic volume, stroke volume, pulmonary transit time, cardiac output, and diastolic ventricular filling rate were determined by the radionuclide technique. Before operation, patients with mitral stenosis had characteristic changes from rest to exercise which supported restriction to diastolic ventricular filling as the primary limitation in generating a cardiac output during exercise. The stroke volume was unchanged from rest to exercise. Thus the cardiac output during exercise was heart rate dependent. However, after commissurotomy the stroke volume increased from rest to exercise. Therefore, cardiac output during exercise was achieved by heart rate and an augmented stroke volume. Moreover, the pulmonary transit time was reduced during rest and exercise after operation. The maximum ventricular ejection and filling rates were markedly increased during rest and exercise after commissurotomy. These differences in hemodynamic parameters at rest and during exercise document the mechanics of increased exercise tolerance in patients with mitral stenosis after mitral commissurotomy.

Adult↗
PubMed1979

Noninvasive radionuclide assessment of cardiac function in patients with peripheral vascular disease.

Disorders of the peripheral vascular system often are associated with heart disease which may increase operative risk. The purpose of this study was to investigate the clinical usefulness of radionuclide angiocardiography for evaluation of cardiac function in patients with vascular disorders. This simple procedure provides measurements of cardiac output, pulmonary blood volume, and left ventricular end-diastolic volume, stroke volume, and ejection fraction with no significant risk or discomfort to the patient. A total of 22 patients with vascular disorders were studied by this technique. Five patients had systemic arteriovenous malformations. The cardiac output, end-diastolic volume, and stroke volume were documented to be greater than normal in these patients before operation. In three patients studied following closure of the arteriovenous fistula, the cardiac output, left ventricular end-diastolic volume, and stroke volume decreased. Postoperative changes in left ventricular ejection fraction were variable. A group of 17 patients with atherosclerotic vascular disease underwent cardiac evaluation. In nine patients with no history of cardiac disease, the lowest ejection fraction of 0.45 occurred in a patient with a saccular thoracic aneurysm, the only patient of the 22 who died after operation. A wide variation in ejection fraction was observed in patients with a history of cardiac disease which ranged from 0.32 to 0.86. Objective documentation of cardiac function by radionuclide angiocardiography would appear to enhance the management of patients with peripheral vascular disorders.

Adult↗
PubMed1978

Cimetidine: prophylaxis against upper gastrointestinal haemorrhage after renal transplantation.

The incidence of upper gastrointestinal haemorrhage within four months of renal transplantation was studied in two groups of patients. Thirty patients who received prophylactic cimetidine suffered no episodes of upper gastrointestinal haemorrhage, while six of the 33 patients who did not receive cimetidine suffered haemorrhages and one of them died as a result. The difference between the groups was significant. The results suggest that the prophylactic use of cimetidine in patients receiving renal transplants is worth while.

Adolescent↗
PubMed1978

Synthesis, toxicity, and cardiovascular properties of N-aralkyl- and N-acyl-5-aminoethylindans.

Secondary amines and amides of 5-aminoethyl-6-methoxyindan and 5-aminoethyl-6-methylindan were synthesized, and the blood pressure lowering effects and accompanying changes in heart rate were evaluated in the unanesthetized desoxycorticosterone acetate hypertensive rat. The acute toxicities of the compounds were determined in mice. The amines were significantly more potent than the amides as antihypertensive agents and also were more toxic. 5-(3,4-Dimethoxybenzyl)aminoethyl-6-methylindan produced the greatest depression in systolic blood pressure at the dose level studied. Structure-activity relationships relevant to blood pressure lowering, heart rate, and toxicity are discussed.

Animals↗
PubMed1978

In vitro bioactivity of insulin analogues: lipogenic and anti-lipolytic potency and their interaction with the effect of native insulin.

This paper presents a survey of the biological potencies of a variety of naturally-occurring and semi-synthetic insulin analogues and a study of the joint biological action of some of these materials with native insulin. Biological activity was tested on isolated rat fat cells using lipogenesis from glucose as the metabolic index. A brief comparison using inhibition of fat cell lipolysis was included. The results indicated: 1. Analogue potencies varied considerably (0.4-100% insulin activity). Values obtained were mainly confirmatory but included two further B1-modified materials and a tricarbamylated insulin. The results supported previous indications on the relative roles of the A1, B1, and B29 residues of insulin for hormone activity. 2. Analogue bioactivities, whether assessed by stimulation of lipogenesis or inhibition of lipolysis, were similar for the four materials tested in both systems. The response of fat cells with respect to both metabolic indices occurred over a comparable range of insulin concentrations, with half maximal effects at 30-35 pmol 1(-1) insulin. 3. The presence of modified insulins appeared to alter the biological action of native insulin in vitro. Small effects of both potentiation and antagonism were identified.

Adipose Tissue↗
PubMed1978

Cardiac function at rest and during exercise in normals and in patients with coronary heart disease: evaluation by radionuclide angiocardiography.

This study demonstrates that radionuclide angiocardiography provides a simple and noninvasive approach for evaluation of myocardial function. Previous work concerning myocardial performance has been generally conducted with the patient in the supine position. Radionuclide angiocardiograms were performed in the present study at rest and during exercise in 30 normal subjects and in 30 patients with ischemic coronary artery disease. There were 30 normal controls (Group I), ten with single coronary artery disease (Group II), and 20 patients with multiple vessel coronary disease (Group III). All subjects were studied in the erect posture on a bicycle ergometer. In the normal controls, the mean heart rate doubled and the cardiac output tripled during exercise. Intensive training can lead to extraordinary levels of cardiac performance as shown in a world-class athlete who during peak exercise attained a heart rate of 210, an ejection fraction of 97%, and a cardiac output of 56 litres per minute. In the patients with coronary artery disease, both groups, were able to increase cardiac output to approximately twice the resting value. The magnitude of increase in blood pressure during exercise was not significantly different in the three groups. However, definite changes were present in the end-diastolic volume at rest was 116 and rose to 128 ml in Group I, 93 rising to 132 ml in Group II, and 138 increasing to 216 ml in Group III. The stroke volume increased comparably in all three groups, but the ejection fraction from rest to exercise showed a marked contrast in the controls compared to those with multivessel coronary disease. The ejection fraction rose in Group I from 66 to 80% during exercise, while in Group II it fell from 69 to 67%, and in Group III from 60 to 46%. These findings indicate that patients with ischemic myocardial disease respond to the stress of exercise by cardiac dilatation to maintain of increase stroke volume at increased heart rates. Moreover, the magnitude of this response appears to be greatest in patients with left main coronary artery stenosis. This approach for evaluating myocardial function during exercise provides useful data of importance in selecting medical versus surgical management of patients with ischemic coronary artery disease.

Adult↗