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Biomedical subjects

T D Giles

Publications and source records attributed to T D Giles.

At least 109 records · Page 6Linked to original sources
PubMed1981

Cardiopulmonary pharmacology of enkephalins in the conscious dog.

Various enkephalins (ENK) have been reported to alter heart rate, systemic blood pressure, and respiratory function but with variable results. We previously found that pentobarbital anesthesia reversed the increases in heart rate and systemic arterial blood pressure produced by Leu5-ENK in the dog. We have now studied the cardiopulmonary responses to systemically injected enkephalins in the awake, chronically instrumented dog. In these unanesthetized dogs, Leu5-ENK, Met5-ENK, and an ENK dimer increased heart rate, systemic arterial pressure, and respiratory rate in a dose-dependent fashion. D-Phe4, Met5-ENK, an analog with behavioral activity but without analgesic or in vitro opiate effects was inactive. Leu5-ENK was studied in detail; typically, heart rate and systemic pressure increased within 20 sec and returned to baseline in less than 180 sec. Intra-arterial injections produced a smaller increase in heart rate than did intravenous injections, but similar increases in systemic arterial blood pressure were recorded. These cardiovascular responses suggest that systemically injected enkephalins suppress baroreceptor reflexes and may have a role in cardiopulmonary regulation.

Animals↗
PubMed1981

Short-term effects of intravenous clonidine in congestive heart failure.

After intravenous bolus injections of clonidine HCl (150 micrograms) to 12 patients with congestive heart failure, peak effects appeared in 5 to 20 min. Clonidine reduced heart rate from 94 +/- 14 to 82 +/- 14 bpm (mean +/- SD, P less than 0.05), left ventricular filling pressure from 31 +/- 5 to 23 +/- 5 mm Hg (P less than 0.001), mean systemic arterial pressure from 98 +/- 13 to 82 +/- 13 mm Hg (P less than 0.001), mean pulmonary artery pressure from 46 +/- 6 to 38 +/- 6 mm Hg (P less than 0.001), and right atrial pressure from 14 +/- 5 to 11 +/- 5 mm Hg (P less than 0.05). Cardiac index increased from 1.6 +/- 0.4 to 1.8 +/- 0.6 l/min/m2 (P less than 0.05) and stroke volume from 32 +/- 10 to 43+/- 12 ml/beat (P less than 0.05). Systemic vascular resistance decreased from 2,342 +/- 800 to 1,795 +/- 345 dynes sec cm-5 (P less than 0.05) and pulmonary vascular resistance from 365 +/- 158 to 263 +/- 114 dynes sec cm-5 (P less than 0.05). We conclude that clonidine decreases heart rate and left ventricular preload and afterload in congestive heart failure.

Adult↗
PubMed1981

The cardiomyopathy of hypoparathyroidism. Another reversible form of heart muscle disease.

A patient with traumatic hypoparathyroidism had cardiomyopathy and congestive heart failure. The patient had no history of preexisting cardiac disease, alcohol abuse, hyperthyroidism, or hypothyroidism and improved greatly with treatment of hypoparathyroidism. We suggest that the cardiomyopathy seen in hypoparathyroidism. We suggest that the cardiomyopathy seen in hypoparathyroidism is due to many factors, but that hypocalcemia and possibly hypomagnesemia are especially important, and that correction of calcium and magnesium deficiencies may result in near-normal cardiac function.

Cardiomyopathies↗
PubMed1981

The prolonged effect of pentaerythritol tetranitrate on exercise capacity in stable effort angina pectoris.

We studied the effect of a single oral dose of 40 mg of pentaerythritol tetranitrate (PETN) on the exercise capacity of ten patients with angina pectoris. The study design was a randomized double-blind crossover comparing the effects of 40 mg of oral PETN with placebo on exercise tolerance. Patients were exercised to moderate angina pectoris before and 2 1/2 and 4 1/2 hours after receiving the placebo or PETN at seven-day intervals during the double-blind crossover period. Exercise tolerance time was measured using a multistage, progressive treadmill test. Exercise times were greater 2 1/2 hours and 4 1/2 hours following PETN compared with placebo (P less than 0.05). Heart rate, systolic and diastolic blood pressure, and double product at rest (supine and standing) and at point of angina pectoris did not change significantly.

Administration, Oral↗
PubMed1980

Coronary artery pain. A possible cause of graft occlusion in a patient with fixed obstructive coronary artery disease.

We describe a 50-year-old man with rest angina and ECG anterior wall subendocardial ischemia. During coronary angiography, a high-grade proximal left anterior descending stenosis was present. Spontaneous total spasm distal to the lesion occurred without chest pain or ST segment shifts. The patient underwent aortocoronary bypass surgery and continued to have the same pain as preoperatively. Repeated catheterization demonstrated total occlusion of the bypass graft with unchanged native coronary vessels. This suggests prolonged coronary artery spasm as the mechanism for graft occlusion.

Angina Pectoris, Variant↗
PubMed1978

Echocardiographic findings in amyloid cardiomyopathy.

Echocardiographic manifestations of two patients with cardiac amyloidosis are presented. The findings consisted of increased thickness of the left ventricular posterior wall and interventricular septal wall, a normal to small left ventricular cavity, and pericardial effusion. The echocardiograph is useful in the evaluation of patients with cardiomyopathy and congestive heart failure.

Aged↗
PubMed1977

The small coronary arteries in alcoholic cardiomyopathy.

The small coronary arteries of two patients with alcoholic cardiomyopathy were studied by means of fine particle barium injection and soft x-ray technic. The spatial architecture of these small arteries which penetrated into the depth of the right and left ventricular myocardium were normal. Their lumina were somewhat dilated and their luminal surfaces were smooth. The "tree circulatory units" were described from this study and were found to be normal. The left ventricular myocardium was richly supplied with small arteries, whereas the myocardium of the right ventricle was not so richly supplied. The myocardium of the papillary muscles and the trabeculae carneae of the left ventricle also had a good supply of small arteries, as did the remote endocardial myocardial appendages. Numerous fine hair-like arteries extended to the epicardial myocardium of the right ventricle to form a brush-like appearance.

Adult↗
PubMed1976

Respiratory syncytial virus and heart disease. A report of two cases.

Two patients had cardiac disease and serological evidence for respiratory syncytial virus (RSV) infection. The first patient had myocarditis and complete atrioventricular heart block with repeated syncopal episodes two weeks following infection. The second patient had alcoholic cardiomyopathy and worsening congestive heart failure associated with RSV infection. The significance of RSV infection in these two patients may bear a significant relationship to sudden infant death syndrome, chronic cardiomyopathy, and alcohol-related heart disease. Cardiac disease secondary to RSV infection may be more prevalent than is presently recognized.

Adolescent↗
PubMed1976

Clinical evaluation of aortic and mitral valve prostheses.

The clinical follow-up for a large number of patients with aortic and mitral valve prostheses is now the responsibility of the general internist and cardiologist, particularly those physicians who recommended operation. Proper follow-up of patients with prosthetic heart valves can be performed only if the physician is aware of the "natural history" of the patient following valve replacement as well as of the common complications associated with cardiac valve prostheses. This article discusses the hemodynamic changes which follow cardiac valve replacement, complications associated with valve replacement (congestive heart failure, suture disruption, "ball variance," thromboembolism, hemolysis, cardiomyopathy, etc.) and simple clinical means of detecting these complications. Some special techniques which may be useful in diagnosing complications of prosthetic cardiac valve malfunction are described. It is emphasized that the physician should not consider the patient "cured" once he has undergone cardiac valve replacement, but rather should consider him to be the subject of meticulous long-term medical care.

Anemia, Hemolytic↗
PubMed1975

Effect of glucagon on digital circulation.

The effect of glucagon on the digital circulation was studied in 7 subjects using the digital rheoplethysmograph (RPG). Rheoplethysmograms were continuously recorded while glucagon (0.1 to 2.0 mg) was injected into the brachial artery of the same extremity being studied with the RPG. The injection of glucagon was associated with a "tingling" or "burning" sensation in 3 subjects. The initial response, which was maximal 8 to 27 sec after the injection of glucagon, was constriction of the arteries, veins, and A-V shunts. The late response consisted of reopening of the arteries and veins. However, in some patients, there was RPG evidence of persistent constriction of the A-V shunts. It is suggested that the late response is similar to that observed in reactive hyperemia and following injection of bradykinin and, therefore, may be related to local release of vasoactive substances by glucagon.

Fingers↗