Biomedical subjects
Publications and source records attributed to T W Rooke.
Experiments were performed on helically cut strips from coronary artery and saphenous vein to determine the relative influence of metabolic versus respiratory acid-base changes. Tensions were measured over a range of various HCO3- concentrations and pCO2's. The results suggest that tension is influenced by extracellular pH and is independent of pCO2.
We tested the hypothesis that arachidonic acid metabolites mediate the coronary vascular response to changes in cardiac activity. Isoproterenol was administered intravenously to five chloralose-anesthetized, open-chest dogs. Left anterior descending coronary artery blood flow, systemic arterial blood pressure, and great cardiac vein O2 content were continuously measured, and blood gas determination (including O2 content) were made before and after infusions. From these data, coronary vascular conductance, coronary O2 delivery, and myocardial O2 consumption were calculated. Isoproterenol increased conductance, O2 delivery, and O2 consumption. Indomethacin, a blocker of prostaglandin synthesis, was administered, and the isoproterenol infusions were repeated. The changes in conductance, O2 delivery, and O2 consumption associated with isoproterenol were not different after indomethacin was administered than before indomethacin was administered. Neither were the relations between conductance or O2 delivery and O2 consumption affected by indomethacin. We conclude that, in this preparation and with this stimulus, prostaglandins do not appear to mediate or modulate the coronary vascular response to changes in cardiac activity.
Cardiologists who are familiar with the techniques and the performance of echocardiography can easily learn how to study the lower extremity veins in their patients by using ultrasound imaging combined with pulsed-wave Doppler echocardiography (duplex scanning). In particular, duplex scanning is useful for diagnosing deep or superficial venous thrombosis, for assessing venous incompetence, and for mapping the superficial veins before surgical harvesting for bypass operations. Because questions about the veins arise frequently in the treatment of cardiovascular patients, the cardiologist who is knowledgeable about veins and venous disease can play a central role in the diagnostic workup and treatment of these patients.
Transcutaneous oximetry is gaining worldwide acceptance as a simple and effective means of evaluating the cutaneous circulation. Oximetry involves the use of Clark-type electrically heated oxygen-sensing electrodes that are attached to the skin; various protocols for the performance of studies (utilizing exercise, oxygen inhalation, leg elevation, and various other maneuvers) have been developed which may improve the accuracy when used in certain settings. Applications for transcutaneous oximetry are found in areas such as: (1) diagnosis of disease, (2) quantification of disease severity, (3) prediction of healing potential for skin ulcers or amputation sites, (4) assessment of microvascular disease, and (5) determination of cutaneous vasomotor status. Transcutaneous oxygen tension serves as an index of the adequacy of skin blood flow, and therefore yields valuable "functional" information not provided by noninvasive "anatomical" testing modalities such as echo-doppler ultrasound imaging.