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Four Greyhound dogs and six horses were utilized to study the physiological mechanisms associated with the development of an exercise training-induced hypervolemia. The animals were used in two separate experiments and were trained for 14 days on a treadmill ergometer and the data were used to formulate conclusions regarding the physiological and practical implications related to the phenomenon. The data reported in this dissertation indicated that exercise training will cause an expansion of the plasma volume in the Greyhound dog (+27%, P < 0.05) and the horse (+29.1% P < 0.05). Physiologically the result is similar in man, the dog, and the horse, however, the mechanisms by which this adaptation is reached appears to differ in each of the species. In the dog, water intake (+33%, P < 0.05) appears to be the primary mechanism for the increase in fluid volume. In the horse, renal control mechanisms (24-hr urine output -24.5%, P < 0.05) appear to be the primary mechanism with those that control the retention of solutes other than sodium predominating over those that control the reabsorption of sodium and water. Based upon the literature, it appears that in man, renal mechanisms predominate the hypervolemic response and mechanisms which control the conservation of sodium appear to be most active in the defense of the tonicity and volume of the vascular compartment. These species differences are important to the understanding of the physiology behind the onset of the training-induced hypervolemia and they provide pertinent information upon which decisions regarding the choice of animal models for future research.

Circulating RNA offers a new detection approach for non-invasive diagnosis. Over the past few years, much effort has been spent on the investigation of possible detection of circulating RNA in plasma. In this thesis, we aim to quantify and characterize cell-free RNA in plasma, and investigate the possibility of using circulating fetal RNA in maternal plasma for non-invasive prenatal diagnosis or monitoring. / In the first part of the thesis, the particle-associated nature of circulating RNA was investigated. Quantitative real-time reverse-transcriptase polymerase chain reaction was developed to measure circulating RNA in healthy individuals and hepatocellular carcinoma (HCC) patients. By subjecting plasma samples to filtration and ultracentrifugation, the presence of both particle-associated and non-particle-associated mRNA species was demonstrated in human plasma. In HCC patents, both the circulating particle- and non-particle-associated plasma RNA concentrations were increased. / The discovery of circulating nucleic acids in plasma and serum has led to the development of numerous promising non-invasive diagnostic tests. The initial non-invasive tests mainly target circulating DNA species. For prenatal diagnosis, circulating fetal DNA in maternal plasma has been utilized for the non-invasive determination of a number of fetal genetic traits. However, as fetal and maternal DNA species co-exist in maternal plasma, these DNA based diagnostic applications depend largely on the use of genetic markers that could discriminate between fetal and maternal DNA, such as the Y chromosome of a male fetus. Thus, a particular DNA marker could only be used in a proportion of pregnancies. This limitation has prompted a quest to develop new fetal nucleic acid markers that are independent of sex or polymorphism and that can be used in all pregnancies. / The existence of circulating RNA is an extraordinary finding because RNA is more labile than DNA and ribonuclease is known to be present in blood. The second study of the thesis reveals that circulating RNA is surprisingly stable under different preanalytical situations. This information has made the study of circulating RNA simpler and more practical for clinical uses. / The third part of this thesis aims at detecting circulating fetal RNA in the plasma of pregnant women. We showed that two placental-derived mRNA species, namely those transcribed from the genes coding for human placental lactogen (hPL) and the beta-subunit of human chorionic gonadotropin (betahCG), are readily detectable in maternal plasma. (Abstract shortened by UMI.) / Tsui Bo Yin. / "May 2005." / Adviser: Y. M. Dennis Lo. / Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0074. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 166-189). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Optimising recovery post-game or post-training could provide a competitive advantage to an athlete, especially if more than one bout of exercise is performed in a day. Active recovery is one common method that is thought to enhance the recovery process. Another recovery method that is gaining popularity is water immersion. The objective of this thesis was to analyse whether these two recovery methods provided greater recovery from explosive exercise than passive recovery. A physiological rationale that may explain the possibility of enhanced recovery with water immersion was initially investigated. The literature surrounding active recovery, water immersion and passive recovery on strength, cycling, running and jumping was then examined. Following these reviews an experimental study was conducted investigating the effects of water immersion, active recovery and passive recovery conducted after repeated bouts of explosive exercise. The rationale for active recovery post-exercise is that during intense exercise, fluid from the blood is forced into the working muscles due to the increase in mean arterial pressure, which increases muscle volume and decreases blood plasma fraction. Active recovery reduces this exercise induced edema and, with an associated increase in blood flow throughout the body, may increase the metabolism of waste substrates produced during exercise. Researchers have observed this increased substrate metabolism with reductions in post-exercise blood lactate accumulation following active recovery. Water immersion would appear to cause a similar physiological response to active recovery without the need to expend extra energy. When a large portion of the body is immersed, hydrostatic pressure acts on the body's fluids within the immersed region. Fluids from the extravascular space move into the vascular system reducing exercise-induced increases in muscular volume and reducing soft tissue inflammation. Additionally, blood volume increases and is redistributed towards the central cavity, which in turn increases cardiac preload, stroke volume, cardiac output, and blood flow throughout the body. Cardiac output increases in relation to the depth of immersion and have been observed to increase by as much as 102% during head-out immersions. These cardiovascular responses occur without any increase in energy expenditure. If extra-intravascular fluid movement is enhanced, then the movement and metabolism of waste substrates could increase. Observations of increased post-exercise blood lactate clearance with water immersion would support this theory. Most methodologies studying the performance benefits of active recovery and water immersion suffer many limitations. These limitations often consist of the experimental time schedule not replicating what is likely to occur in a practical situation, no isolation of water temperature and hydrostatic pressure effects, and lack of a sport-like exercise consisting of repeated expressions of explosive power. Light-intensity active recovery and water immersion do not appear to be detrimental to performance, but neither does there appear to be enough evidence to claim they are beneficial. Effects of active recovery and water immersion would seem to be trivial to small, with any benefits more likely following multiple bouts of high-intensity exercise and recovery or following muscle damaging exercise. There may be a link between blood plasma fraction and performance, however, evidence is inconclusive. Given these issues and limitations the aim of this research was to investigate whether combinations of active recovery, water immersion and passive recovery could maintain peak power and work during subsequent bouts of explosive exercise. We also investigated whether there was any difference in subjects' blood plasma faction and perceived fatigue between the recovery modes. A cross-over experiment was conducted on seven subjects over four weeks. On the same day of each week subjects performed three sessions of maximal jumping, each two hours apart, followed by a different recovery method. Each jump session consisted of three sets of 20 maximal jumps repeated every three seconds, with a minute's rest in-between. Immediately following the jumping subjects performed 10 minutes of either (A) active recovery on a cycle ergometer followed by seated rest, (I) immersion to the gluteal fold in 19°C water followed by seated rest, (AI) active recovery followed by immersion, or (P) seated passive rest. Jumping was conducted on an instrumented supine squat machine that allowed the measurement of total peak power and total work. Pre-jump, post jump and post-recovery blood was taken and the percentage of blood plasma fraction calculated. Perceived leg fatigue was also measured at these times. Observed differences in total peak power and total work between the recovery modes were non-significant. No differences were observed in the change of blood plasma fraction between the recovery modes or perceived fatigue. One reason for any lack of difference between the recovery modes may have been the brevity of the recovery time. Research that has observed significant benefits of active recovery and water immersion compared to passive recovery have used recovery times greater of 15 minutes or more. Additionally, changes in blood plasma fraction between active recovery, water immersion and passive recovery have not been apparent until at least 10 minutes post-recovery in previous research. Alternatively, rather than brevity, it may be that active recovery or water immersion simply does not provide any benefit to performance recovery. Overall there is a meagre amount of research into active recovery, water immersion and passive recovery. Further research that incorporates a variety of exercise and recovery protocols is required.

Graduation date: 1999

Optimising recovery post-game or post-training could provide a competitive advantage to an athlete, especially if more than one bout of exercise is performed in a day. Active recovery is one common method that is thought to enhance the recovery process. Another recovery method that is gaining popularity is water immersion. The objective of this thesis was to analyse whether these two recovery methods provided greater recovery from explosive exercise than passive recovery. A physiological rationale that may explain the possibility of enhanced recovery with water immersion was initially investigated. The literature surrounding active recovery, water immersion and passive recovery on strength, cycling, running and jumping was then examined. Following these reviews an experimental study was conducted investigating the effects of water immersion, active recovery and passive recovery conducted after repeated bouts of explosive exercise. The rationale for active recovery post-exercise is that during intense exercise, fluid from the blood is forced into the working muscles due to the increase in mean arterial pressure, which increases muscle volume and decreases blood plasma fraction. Active recovery reduces this exercise induced edema and, with an associated increase in blood flow throughout the body, may increase the metabolism of waste substrates produced during exercise. Researchers have observed this increased substrate metabolism with reductions in post-exercise blood lactate accumulation following active recovery. Water immersion would appear to cause a similar physiological response to active recovery without the need to expend extra energy. When a large portion of the body is immersed, hydrostatic pressure acts on the body's fluids within the immersed region. Fluids from the extravascular space move into the vascular system reducing exercise-induced increases in muscular volume and reducing soft tissue inflammation. Additionally, blood volume increases and is redistributed towards the central cavity, which in turn increases cardiac preload, stroke volume, cardiac output, and blood flow throughout the body. Cardiac output increases in relation to the depth of immersion and have been observed to increase by as much as 102% during head-out immersions. These cardiovascular responses occur without any increase in energy expenditure. If extra-intravascular fluid movement is enhanced, then the movement and metabolism of waste substrates could increase. Observations of increased post-exercise blood lactate clearance with water immersion would support this theory. Most methodologies studying the performance benefits of active recovery and water immersion suffer many limitations. These limitations often consist of the experimental time schedule not replicating what is likely to occur in a practical situation, no isolation of water temperature and hydrostatic pressure effects, and lack of a sport-like exercise consisting of repeated expressions of explosive power. Light-intensity active recovery and water immersion do not appear to be detrimental to performance, but neither does there appear to be enough evidence to claim they are beneficial. Effects of active recovery and water immersion would seem to be trivial to small, with any benefits more likely following multiple bouts of high-intensity exercise and recovery or following muscle damaging exercise. There may be a link between blood plasma fraction and performance, however, evidence is inconclusive. Given these issues and limitations the aim of this research was to investigate whether combinations of active recovery, water immersion and passive recovery could maintain peak power and work during subsequent bouts of explosive exercise. We also investigated whether there was any difference in subjects' blood plasma faction and perceived fatigue between the recovery modes. A cross-over experiment was conducted on seven subjects over four weeks. On the same day of each week subjects performed three sessions of maximal jumping, each two hours apart, followed by a different recovery method. Each jump session consisted of three sets of 20 maximal jumps repeated every three seconds, with a minute's rest in-between. Immediately following the jumping subjects performed 10 minutes of either (A) active recovery on a cycle ergometer followed by seated rest, (I) immersion to the gluteal fold in 19°C water followed by seated rest, (AI) active recovery followed by immersion, or (P) seated passive rest. Jumping was conducted on an instrumented supine squat machine that allowed the measurement of total peak power and total work. Pre-jump, post jump and post-recovery blood was taken and the percentage of blood plasma fraction calculated. Perceived leg fatigue was also measured at these times. Observed differences in total peak power and total work between the recovery modes were non-significant. No differences were observed in the change of blood plasma fraction between the recovery modes or perceived fatigue. One reason for any lack of difference between the recovery modes may have been the brevity of the recovery time. Research that has observed significant benefits of active recovery and water immersion compared to passive recovery have used recovery times greater of 15 minutes or more. Additionally, changes in blood plasma fraction between active recovery, water immersion and passive recovery have not been apparent until at least 10 minutes post-recovery in previous research. Alternatively, rather than brevity, it may be that active recovery or water immersion simply does not provide any benefit to performance recovery. Overall there is a meagre amount of research into active recovery, water immersion and passive recovery. Further research that incorporates a variety of exercise and recovery protocols is required.

Thesis (doctoral)--Göteborg University, 1998. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (M.S.)--Ohio University, November, 2004. / Includes bibliographical references (p. 83-90)

Thesis (doctoral)--Göteborg University, 1998. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (M.S.)--Brigham Young University. Dept. of Exercise Sciences, 2007. / Includes bibliographical references.