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Biomedical subjects

J Ross

Publications and source records attributed to J Ross.

At least 667 records · Page 37Linked to original sources
PubMed1980

Significance of regional wall thickening abnormalities relative to transmural myocardial perfusion in anesthetized dogs.

In 15 open-chest, anesthetized dogs, regional systolic wall thickening (% delta WT) was measured with sonomicrometry and regional blood flow was determined with tracer microspheres (7-10 micron) before and after various degrees of coronary artery narrowing were created with a hydraulic occluder. The stenoses were categorized into four groups by the effect on % delta WT, and the corresponding myocardial blood flow (MBF) was determined in four layers across the ventricular wall (layer 1: subendocardium; layer 4: subepicardium). In group 1, % delta WT decreased 44 +/- 10% and only layer 1 MBF was significantly reduced (-28%); in group 2, % delta WT decreased 77 +/- 8% and MBF was reduced in both layers 1 and 2 (-52% and -36%, respectively); in group 3, % delta WT decreased 104 +/- 3% and MBF was reduced in the three inner layers (layer 1: -65%; layer 2: -58%; layer 3: -34%); in group 4, % delta WT decreased 145 +/- 9% (systolic wall thinning) and transmural reduction of MBF was found (layer 1: -74%; layer 2: -68%; layer 3: -55%; layer 4: -29%). We conclude that (1) up to 75% reduction in systolic wall thickening may occur when perfusion to only the inner one-half of the myocardium is decreased; (2) akinetic wall motion may be observed when perfusion remains normal in the subepicardial one-fourth of the wall; and (3) dyskinesia (wall thinning) occurs when blood flow is reduced transmurally.

Anesthesia↗
PubMed1980

The use of former phobics in the treatment of phobias.

The author describes the role of the phobia therapist, usually a former phobic or a mental health worker. The therapist works with a psychiatrist as part of an overall psychiatric treatment program that provides an effective, low-cost approach to the treatment of phobias. Case studies illustrate how the supported-exposure approach, whereby patients are confronted gradually with the fearful situation in a real-life setting, enables phobics to learn how to deal with their phobic symptoms while they are occurring.

Agoraphobia↗
PubMed1980

Left ventricular wall stress and aortic input impedance.

The systolic load faced by the left ventricle has been approached from several different aspects over the past decade. One major approach relates instantaneous levels of ventricular wall stress to ventricular systolic load. This approach, based on a large body of information on in vitro performance of muscle, has provided substantial insight into factors influencing ventricular performance. Another equally useful approach to describing ventricular load has been to assess the hydraulic load faced by the ventricle as arterial input impedance or by pulse transmission wave theory. The studies reviewed and the data presented in this article clearly show that in the intact, but open-chest anesthetized preparation, alterations in characteristic impedance are indeed reflected by alterations in ventricular performance, but these alterations are also reflected by alterations in ventricular wall stress that more adequately predict alterations in ventricular shortening associated with changes in load. Moreover, changes in input impedance do not, in themselves, appear to influence the force-velocity-length framework for examining ventricular function.

Animals↗
PubMed1980

Cardiac rehabilitation: evidence for improvement in myocardial perfusion and function.

Sixteen patients with coronary heart disease (CHD) were studied with rest and exercise thallium scans and gated radionuclide ventriculography before and after 3 to 12 months of exercise training. The 5 patients presented in this report showed improvement in both the ejection fraction and exercise thallium images after training while achieving a higher maximal workload and an equivalent double product. These radionuclide techniques have provided the 1st documentation of improvement in both myocardial perfusion and function in CHD patients after exercise training. A controlled study using advances in imaging technology with patients matched according to postmyocardial infarction time and by the severity of disease is underway to confirm these findings.

Adult↗