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Biomedical subjects

S A Cook

Publications and source records attributed to S A Cook.

At least 73 records · Page 4Linked to original sources
PubMed1980

Alterations in cardiac function and cardiopulmonary blood volume in chronic sodium depletion in dogs.

1. Chronic sodium depletion in dogs is associated with a blunting of the pressor response to carotid occlusion. AFter section of the vagus nerves this pressor response reverts to normal although atropine is without effect, suggesting a possible role for increased activity of cardiopulmonary vagal afferents in suppressing sympathetic outflow. Since increases in central blood volume stimulate vagal afferents, cardiopulmonary haemodynamics were studied by radioisotope dilution before and after 3 and 4 weeks of dietary sodium restriction together with frusemide. 2. Sodium depletion was associated with significant decreases in cardiac output, ejection fraction and total blood volume; the cardiopulmonary blood volume increased but the change was not statistically significant (P < 0.2). These changes were accompanied by a significant increase in the ratio cardiopulmonary blood volume/total blood volume and a decrease in the ratio cardiac output/cardiopulmonary blood volume. 3. Results indicate that sodium depletion may be accompanied by a paradoxical translocation of blood to the cardiopulmonary region in part due to depressed ventricular performance.

Animals↗
PubMed1980

Abnormal left ventricular relaxation in hypertensive patients.

1. The maximum rates of left ventricular ejection and filling were derived (Fourier analysis) from the left ventricular volume curve (99m technetium-human serum albumin gated blood pool studies) in 12 normotensive subjects and 15 hypertensive patients of matched age groups. 2. Average values of cardiac output, ejection fraction, heart rate and left ventricular ejection rate were not significantly different in the two groups. 3. Hypertensive patients had a slower rate of left ventricular filling (P < 0.05), suggesting diminished left ventricular compliance in hypertension.

Adult↗
PubMed1980

Thallium-20 1 myocardial imaging in young adults with anomalous left coronary artery arising from the pulmonary artery.

Anomalous origin of the left coronary artery from the pulmonary artery (Bland-Garland-White syndrome) may produce myocardial ischemia, infarction, and frequently death in infancy. Some patients, however, develop satisfactory coronary artery collaterals and are relatively asymptomatic into adulthood. Very little is known about their myocardial perfusion patterns. We studied three young adults with this condition using stress thallium-20 1 myocardial imaging. Electrocardiograms in two patients demonstrated old anterolateral myocardial infarctions. Preoperative stress exercise tests were positive in all three patients. Marked perfusion abnormalities were found in the proximal anterolateral wall in all patients, and one patient also had a posterolateral defect. Postoperatively, all stress tests returned to normal. Thallium imaging demonstrated improvement in ischemic areas, but old scars persisted.

Adult↗
PubMed1979

Automated computer program for radionuclide cardiac output determination.

Radionuclides have provided a safe, reliable, and minimally invasive method for repeated determinations of cardiac output. A completely automated computer program for data analysis is described. Cardiac output values obtained by this technique correlated closely with values obtained by manual determination of the region of interest (r = 0.90 for right-ventricular and 0.98 for left-ventricular outputs, p less than 0.001 for both). Further, cardiac output determined by computer selection of either left-ventricular area of interest or of the "whole heart region" correlated significantly with that simultaneously determined by dye-dilution technique (indocyanine green; r = 0.86, p less than 0.001 for both). The automated approach allows greater objectivity in the selection of the regions of interest, faster turnaround of calculated results, and use of a smaller dose of radionuclide.

Adult↗
PubMed1976

Computed tomography of the liver.

This work examines the scope and accuracy of CT in the detection of tumors, abscesses, cysts, and parenchymal disorders of the liver. While CT remains an emerging modality, it is shown to be equal to nuclear medicine in detecting mass lesions. It has also been possible to distinguish obstructive from nonobstructive jaundice. Presently, CT is not well suited to the study of cirrhosis. Technological advances in CT design and contrast agents offer promise of significantly improved resolution.

Biopsy↗
PubMed1976

Preoperative localization of occult lesions of the breast.

An outpatient procedure that accurately localizes occult lesions of the breast has been used in 26 patients. A small biopsy is performed using local anesthesia, the excised specimen is xerographed and, if necessary, bread-loafed to identify the involved specimen. This has corroborated the xeromammographic diagnosis of cancer in six patients in whom the lesions were clinically not detectable.

Biopsy↗
PubMed1975

Computed tomography of the thorax and abdomen; a preliminary report.

The utility of computed tomography (CT) in the study of the anatomy, physiology, and pathology of the human body has been the subject of considerable interest since the introduction of CT scanning. The advent of a new prototype scanning device has made it possible to examine a variety of abnormalities in the abdomen and thorax in a manner not previously possible. This development permits a remarkable insight into the study of human disease in vivo.

Aortography↗