Data were collected from the initial symptom-limited maximal exercise tests of 161 patients without. diagnosed coronary heart disease (CHD). Subjects were grouped according to their systolic (SBP) and diastolic (DBP) blood pressure changes between the final two stages of exercise. / Master of Science

Two groups of horses were each fed either a control diet of ground hay and concentrates (4 horses), or a Similar diet with 10% added fat after undergoing a baseline Standard Exercise Test (SET). The SET was a stepwise, incremental test to exhaustion on an equine treadmill set at a 6% slope. Resting and working heartrates and rectal temperatures were monitored, and venous blood was collected at rest, and every 3 minutes during exercise, just prior to each speed change. Blood was analyzed for pH, hemoglobin, and pCO₂, and base excess and plasma bicarbonate levels were calculated using nomogram equations. Plasma samples were analyzed for albumin at each step, and for sodium, potassium, chloride, and lactate at rest and exhaustion only. The plasma SID was calculated at rest and exhaustion by the following equation: ([Na⁺] + [K⁺]) - ([Cl⁻] + [Lactate]) The SET was performed after 16 days of interval training, and once more after another 16 days of interval training. Differences over time during exercise were found: heartrate, lactate, and potassium increased (p<.001), and hemoglobin increased (P<.01). Decreases were found in PH, pCO₂, bicarbonate concentration, base excess, and chloride (p<.001). Training effects were found in resting and working heartrates, pCO₂, bicarbonate concentration, and base excess, which all decreased during exercise with training. Hemoglobin increased during exercise with training. There were treatment * SET interactions for Strong Ion Difference, base excess, lactate concentration, pCO₂, and pH. There were no differences found between groups for any of the variables measured. Both groups showed improvements in fitness with training, and the fat group had a higher level of plasma lactate by SET 3. These results suggest that a high fat diet combined with interval training may have some effects on plasma lactate, and that training alone can affect many variables. The results also give evidence to support the evaluation of SID during exercise in horses. / Master of Science

In view of the objects set forth in this thesis, and with analysis of the data obtained, a few points in conclusion may be taken as being reasonably true and evident. On the basis of consistently different and respectively characteristic physiologic traits it appears that Beauveria B is distinct from Beauveria A, even though they are essentially similar in morphology and pathogenicity. Whether they are distinct species, or are strains of the same species is unsettled. Physiologic characteristics popular to different species of closely related fungi may be used to supplement morphology and pathogenicity as criteria of classification and reidentification. In the limited host range studies, the Beauveria species were most cosmopolitan in parasitism. The Entomophthora species were largely uninfective for the insects used and under the conditions obtained, possibly having been in culture so long as to loose virulence. Endosclerotium was highly specific for a single host, the mealy bug. In this study of entomogenous fungi, embracing membrane of several representative groups, it does not appear that they can be characterized as a group apart from other fungi on the basis of physiology. They grow saphrophytically on a wide range of some 50 different proteins, sugars, nutrient solid media, and organic acids. In contrasting the physiological characteristics of the slow growing E. saphaerosperma with the other two species of Entomophthora, it can be stated that consistently different physiologic results were correlated with the distinctly different morphology. Further, the near identical physiological behavior by E. apiculata and E. saphaerosperma, paralleled with essentially similar morphology, may prove that these two are one and the same species. In the case of Endosclerotium, it may be observed that slow growth and cultural inflexibility seem to be correlated with extreme host specificity. The liquefaction of gelatin and the peptinization of proteins indicate that the Entomophthora species produce proteinase enzymes in abundance. / Master of Science

The purpose of this study was to evaluate metabolic, cardiorespiratory, and perceptual responses during recumbent cycle ergometry performed at various seat back angles and different work rates. Healthy college-aged men performed steady-state exercise at two work rates, 100 watts (n=46) and 150 watts (n=26), using five back seat angles, 90, 105, 120, 135, and 150 degrees. The results of this study suggest that recumbent seat back angles of 135 to 150 degrees are associated with lower metabolic and cardiorespiratory stress during rest and submaximal exercise than more upright positions. The reduced stress at these angles is accompanied by lower perceptions of exertion and improved seating comfort. The failure of the base-line correction for resting V0 2 to remove the effect of seat back angle implies that the reduced physiological stress associated with these positions is due to reasons other than attenuated resting metabolic costs. It is concluded that the selection of recumbent seat back angles between 135 and 150 degrees can result in improved efficiency, reduced physiological stress, diminished perceptions of exertion, and increased seating comfort.

No description available.

This investigation is a series of four experiments that examine the role of intrauterine steroidogenesis in the pregnant gilt. In chapter 3, ovariectomy (OVX) and medroxyprogesterone acetate (MPA) treatment at two stages of gestation (d19-29 or d59-69) resulted in maintained pregnancy, normal fetal survival rates, normal conceptus development, and typical plasma estrogens when compared to intact, control gilts. In chapter 4, intrauterine steroid synthesis was quantitated by incubating placenta (PLAC) and endometrium (ENDO) from the control and MPA-treated gilts of chapter 1. Placental P₄, estrone (E₁), and estrone sulfate (E₁SO₄) concentrations were significantly higher than ENDO. Progesterone (P₄) production increased between d30 and 70 of pregnancy while E₁ and E₁SO₄ decreased. The addition of pregnenolone (P₅) to the incubation medium enhanced P₄ but not E₁ or E₁SO₄ release. MPA-treatment had no effect on in vitro steroid production. In chapter 5, OVX gilts from 9 stages of gestation (d20, 25, 30, 35, 40, 45, 55, 60, 80 and 90) were administered P₅ until undergoing hysterectomy (10d after OVX). Only 1 of 10 gilts OVX on d20 or 25 was able to maintain pregnancy for the entire treatment period. The pregnancy rate was variable (67-100%) for gilts OVX between d30-45 of gestation and 100% for gilts OVX subsequent to d45. All measures of whole litter survival and conceptus development for gilts that maintained pregnancy were equivalent to those expected under ovarian-intact, untreated conditions. Plasma steroid levels were relatively normal but allantoic P₄ failed to increase late in gestation. In chapter 6, in vitro steroid synthesis by PLAC and ENDO from gilts treated in chapter 5 was evaluated. Placental P₄ production increased as gestation progressed while ENDO P₄ production was low throughout. The addition of P₅ to the incubation medium resulted in increased P₄ synthesis for both tissues at most stages of gestation. Extending the incubation period also resulted in increased P₄ production at several stages of pregnancy. In vitro estrogen production increased markedly as gestation progressed past d65. The addition of P₅ and extended incubation time enhanced E₁ but not E₁SO₄ synthesis. Overall, data indicate that the PLAC and ENDO have a large capacity for steroid synthesis and estrogen synthesis can occur de novo in the absence of ovarian precursors. / Ph. D.

This investigation used a constant-load cycle ergometer as a way of examining relationships between the cycle ergometer and sprint performance. Twenty-five college-aged males were used for this investigation. Following a three minute warm-up, each subject performed a 15 sec. maximal bout on the cycle ergometer. The resistance load on the ergometer was set at 0.12kg/kg of bodyweight. Peak power (PP), average power (AP), time to peak power (TTPP), power fatigue rate (PFR), and power fatigue index (PFI) were computed using a microcomputer system. In addition, PP,AP, and PFR were adjusted for total bodyweight (PP/kg, AP/kg, PFR/kg). On a separate day each subject performed six sprints two each at 50m, 100m, and 200m. Each sprint was electronically timed using an infra-red motion detector and starting blocks were used. Initially low correlations were found between the ergometer parameters and the sprint times (r=.07-.55). However upon closer evaluation stronger relationships appeared to exist for the faster subjects. Therefore, subject subgroups of faster subjects were formed. Subject subgroups for the 5 Om (T<7.5sec.), 100m (T<l4sec.)}, and 200m (T<26.6sec.) showed higher correlations (r=.06-.70). Further analysis revealed that high inter-variable correlations existed between many of the ergometer variables. Based on these correlations the parameters were separated into four groups. Group I contained variables of absolute power (PP,AP), group II were variables of relative power (PP/kg, AP/kg), group III contained variables of fatigue (PFR, PFI, PFR/kg), and group IV consisted of the acceleration variable (TTPP). Equations for predicting sprint performance were developed using one to four variables with only one variable from each group being used. The best equation was considered to be the one that yielded the highest r* value while also yielding the lowest Akakai Information Criteria value and MSE. Variables from the relative power group (PP/kg, AP/kg) and fatigue group (PFR, PFI, PFR/kg) were the best indicators of performance. These results suggest that the cycle ergometer used in this investigation can be used for evaluating the components of sprint performance in untrained males, and that this test is best when compared to the 200 m dash. / Master of Science

A growing body of research suggests that the respiratory system may be limited in its ability to meet the demands of increased ventilitory work. This is supported by studies reporting altered contractile properties of the diaphragm in response to increased ventilations. In order to determine if expiratory muscle function is affected by increased ventilitory demand, this study evaluated maximal expiratory pressure, PeMax, in response to two separate short-term, high-intensity exercise trials. Males (n=7) and females (n=5) not currently in active physical training underwent a VO₂ max test and a constant workload of 90% of VO₂ max. PeMax was measured at rest, immediately post exercise, and at one two and five minutes into recovery for both exercise trials. PeMax values were found to decrease 12% and 17% in response to graded and constant workload conditions respectively (P<.05), and this decline persisted throughout the five minute recovery. No Significant relationship was found between magnitude of decline in PeMax and VO₂ max or decline in PeMax and Ve max. These findings suggest that maximal graded exercise as well as exhaustive constant workload exercise corresponding to 90% of VO₂ max provide the ventilitory stimulus great enough to result in a decline in expiratory performance. / Master of Science

The memory system is adaptive in so far as it is able to provide the most robust predictions of what will happen next in our environment. Three means through which it can do this are: arbitrating between temporally embedded recollections and generalized knowledge; rescuing remote memories that are learned to be behaviorally relevant; and updating existing memories if they provide invalid predictions of the outside world. Here, I cover three studies that probe these functions in behavior and in the brain. In Chapter 1, I show how a data-driven parcellation reveals non-linear gradients in measures of signal heterogeneity across the body of the hippocampus, suggesting novel areas of investigation into how the memory system flexibly constructs fine- and coarse-grained memories. In Chapter 2, I then explore how memories might be rescued by later aversive experiences, finding novel evidence that the online inferences participants make as to what current stimuli are relevant to their arousal subtly shapes what previous stimuli they retroactively maintain in memory. Finally, in Chapter 3, I show that signals from the ventral tegmental area modulate the effect of replaying memories on the eventual updating of those memories. Each of these provides novel pieces of evidence into the neural and behavioral markers of how memories are constructed, strengthened, or updated in the brain.

The US population over the age of 65 years is growing rapidly, with elderly women outnumbering men by 50 percent. Studies show that aging is often accompanied by reduced energy intake, inadequate nutrition, and the loss of lean body mass with a subsequent increase in body fat, as well as the tendency towards inactivity. An increased level of physical activity elevates energy needs, which can lead to increased energy and nutrient intake, and has been shown to aid in the maintenance of lean body mass and the reduction of body fat. Positive health outcomes for seniors depends partly on a clearer understanding of the interrelationships between physical activity, diet, and body composition. The purpose of this study was to determine whether higher overall levels of physical activity among elderly women, were related to higher energy intake, nutrient adequacy, and less body fat, and to what extent age affected these associations. Sixty-three elderly women (aged 65-98 years) volunteers completed a three part study spanning 14 weeks. Mean level of physical activity (MLPA) and mean nutrient intakes were estimated using nine self-reported days of records, three predetermined days from each of three recording periods. MLPA was determined from self-reported hours spent in five physical activity categories (resting, very light, light, moderate, and heavy), multiplied by corresponding weighted factors of intensity (1.0, 1.5, 2.5, 5.0, 7.0, respectively). Nutrient analyses for seven vitamins (vitamin A, vitamin C, thiamin, riboflavin, niacin, vitamin B6, vitamin B12) and three minerals (calcium, iron, and zinc) were done using the Food Processor II computer software. A mean adequacy ratio (MAR) was calculated for each subject as the average percent of the RDA for intakes of all 10 nutrients. Body composition assessment included triplicate measures of: height and weight from which body mass index (BMI) was determined; waist-to-hip ratio (WHR); and an estimation of percent body fat (PBF) from the sum of four skinfolds (triceps, biceps, subscapular, suprailiac). It was determined that MLPA was not directly related to energy intake, nutrient adequacy, or the three body composition parameters. However, the correlation coefficients between MLPA and energy intake, mean adequacy ratio, and percent RDA for 8 of the 10 nutrients were positive, and the correlation coefficients between MLPA and all three body fatness measures were negative, as was expected. The small coefficient of variability of MLPA limited its discriminating power in determining associations with energy intake, nutrient adequacy, and body composition. Backward stepwise regression models were conducted to distinguish potential confounding effects of age, education, and MLPA on the variables kcal/day, kcal/kg/day, MAR, BMI, WHR, and PBF. Age was found to account for the largest portion of the variations, and was greater than the contribution of MLPA for all of these variables, except in the case of kcal/kg/day. When the subjects were divided into young-old (65-74 yr) and old-old (75-98 yr) subgroups, the younger compared to the older women were found to be more active as measured by MLPA (p=.02), explained by their engaging in more light activities of daily living (p=.04). The young-old compared to the old-old women consumed more kcalories/day (p=.01), and had a higher MAR score (p=.00). The nutrient densities of the two groups' diets were not significantly different. The younger women had slightly lower BMI, WHR, and PBF values. This study revealed age, rather than MLPA, was a better predictor of some parameters of diet adequacy and body fatness among this sample of elderly women. In addition, consistently higher levels of physical activity and greater dietary adequacy and was found among the younger compared to the older portions of this sample of senior women, suggesting that nutrition intervention programs for the elderly should encourage daily activeness as a strategy to maintain or improve dietary adequacy with advancing age. / Graduation date: 1993