Inaug.-Diss.--Tübingen. / Vita. Includes bibliographical references.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: valvular interstitial cell, substrate, TGF-B1. Includes bibliographical references (p.44-45).

Thesis (Ph. D.)--University of Virginia, 2006. / Includes bibliographical references (leaves 161, 187). Also available online through Digital Dissertations.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 118-129). Also available in electronic version.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 130-141). Also available in electronic version.

The purpose of this study was to elucidate some of the mechanisms involved in the control of the function of the fish heart. In vitro experiments were conducted to determine the effect of varying input pressure, temperature, and epinephrine concentration on the isolated, perfused, trout heart. In vivo experiments were conducted with chronically implanted flow probes to determine the effect of increased blood epinephrine levels on the activity of the heart of the lingcod. Five variables were measured to describe the activity of the isolated trout heart: rate, stroke volume, cardiac output, stroke work, and heart work per minute. Heart function curves were constructed showing the relationship between each of these variables and the input pressure at two levels of epinephrine, 0.1 ug/ml and 0.01 ug/ml, and at two temperatures, 6°C and 15°C. The isolated trout heart obeyed Starling's law, since the stroke work increased as the filling pressure, and thus the end diastolic fiber length, increased. Increased filling pressure also caused the heart rate to increase, probably due to a direct effect of pressure on the pacemaker cells. Increased temperature produced an increase in rate, which in turn decreased the filling time available between beats and so decreased the stroke volume. Cardiac output was not greatly affected by temperature changes. Low temperature appeared to have a direct inotropic effect on the heart as well; that is, greater stroke work was produced from a given end diastolic volume at low temperatures. Epinephrine had a pronounced inotropic effect at 15°C. The stroke volume, stroke work, cardiac output, and heart work per minute all increased with high epinephrine. The rate decreased, probably because the systolic emptying was so much more complete that a greater time interval between beats was needed to fill the heart. At 6°C the inotropic effect of low temperature masked the inotropic effect of epinephrine, so that high epinephrine produced no change in stroke work or stroke volume. A positive chronotropic effect was pronounced at this temperature. The cardiac output and heart work per minute increased with epinephrine as a result. The adrenergic receptors mediating the responses of the heart to epinephrine were of the β-type only. The responses were blocked by Inderal, a β-receptor blocking agent, but were unaffected by phenoxybenzamine, an ⍺-receptor blocking agent. Increased levels of epinephrine in the blood of the lingcod at 10° - 12°C produced an increase in the mean blood flow in the ventral aorta. The heart rate remained constant, thus the changes in mean blood flow were due to changes in stroke volume. These stroke volume changes could be produced by epinephrine acting on the heart directly via β-receptors in the myocardium or indirectly via changes produced in the rest of the circulatory system. / Science, Faculty of / Zoology, Department of / Graduate

The purposes of the study were: (i) to determine if the recovery rate of ice hockey players is affected by elevation of the legs, massage, and controlled breathing; (ii) to determine the length of recovery time needed for a one-half, one, and one and one-half minute skating period; and (iii) to compare the subjective recovery time with the calculated recovery half-time. One junior varsity and three varsity ice hockey players at the University of British Columbia began the study six weeks after the hockey training season began. Two subjects acted as controls and two subjects acted as experimentals. The testing of both the experimentals and controls was done in three parts. The first part consisted of one-half minute skates, the second part one minute skates, and the third part one and one-half minute skates. Each subject took four separate days to complete each part. On each day he repeated the prescribed skate three times, with rest periods of four and one-half minutes between skates, and a five minute rest period before the first skate. The control group recovered in the normal sitting position for each of the three parts of the experiment, while the experimental group varied the method of recovery using the normal sitting position, massage, elevation of the legs and controlled breathing in each of the three parts of the experiment. The control group was used to determine recovery times in the normal sitting position and to determine if there was any progressive improvement in the recovery time due to conditioning. The subjects also made a subjective estimate of when they felt they had recovered. The study found that there was no pattern of improving recovery times with the two control subjects. The mean recovery half-times ranged from: fifty-three seconds to one minute and forty-two seconds for the one-half minute skate; one minute and nine seconds to one minute and forty-eight seconds for the one minute skate; and one minute and eighteen seconds to two minutes and twelve seconds for the one and one-half minute skate. In every skating session with the two experimental subjects, elevation of the legs produced the lowest mean recovery half-times of the four different recovery methods. Subjects L.B. and K.M. both showed a significant difference between the mean recovery half-times of the normal sitting and elevation of the legs at the five per cent level of confidence for the one-half minute skates and subject K.M. showed a significant difference at the five per cent level of confidence in the one and one-half minute skate. The controlled breathing method of recovery produced mean recovery half-times that were lower than normal sitting mean recovery half-times in every skating period. However, the mean recovery half-times for controlled breathing were not as low as the mean recovery half-times for elevation of the legs. The massage method of recovery produced greater mean recovery half-times compared to the normal sitting recovery method in each skating time period with only one exception. In all skating sessions with one exception, the third trial recovery half-time was greater than the first trial recovery half-time. Generally, the subjective recovery times were closer to the calculated recovery half-times with the one-half and one minute skates than with the one and one-half minute skates. / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate

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