Abstract PO2 DEPENDENCE OF OXYGEN CONSUMPTION IN SKELETAL MUSCLE OF DIABETIC AND NON-DIABETIC RATS By: Alexander C. Liles A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at the Medical College of Virginia Campus, Virginia Commonwealth University Virginia Commonwealth University, 2017 Advisor: Roland N. Pittman, Ph.D. Department of Physiology and Biophysics Type 2 diabetes mellitus (T2DM) is a major medical problem around the world, affecting nearly 6% of the world’s population. This study was an attempt to better understand physiological changes the disease may cause to the microcirculation and more specifically, to assess the dependence of oxygen consumption in skeletal muscle of a diabetic animal model. The spinotrapezius muscles of Goto-Kakizaki (G-K) and Wistar control rats were used to measure interstitial using phosphorescence quenching microscopy. The G-K rats spontaneously develop T2DM and serve as an appropriate model for the disease in humans. By rapidly arresting blood flow in the tissue and observing the resulting changes, an oxygen disappearance curve (ODC) was created. The ODC was used to calculate oxygen consumption rate (VO2) over the physiological range of PO2 values. The resulting VO2 vs PO2 curves were analyzed using Hill’s equation to fit the data and obtain values of several key parameters to quantitatively describe the PO2 dependence of oxygen consumption. When compared to healthy control rats, the G-K rats exhibited a significantly higher Vmax, or maximum rate of oxygen consumption, compared to the Wistar rats. The two rat sub-strains had similar values for P50, which indicates the PO2 at half maximal consumption. The overall higher maximal rate of consumption by the diseased animals could be explained by some disconnect in the consumption of oxygen by the mitochondria and the normal corresponding production of ATP. In conclusion, it was demonstrated that in situ muscle tissue from both diabetic and non-diabetic rats had a PO2 dependence of oxygen consumption over a wide range of PO2 values and the muscles of diabetic animals consumed oxygen at a higher maximal rate.

Adult chickens employ endothermy – internal generation of heat that maintains a constant body temperature (Tb). Prior to hatching, chicken embryos are ectothermic - controlling Tb by external heat sources. Upon hatching, the hatchling transitions from an ectotherm to an endotherm that has been shown to be delayed by hypoxia. In this study, whole animal oxygen consumption () and liver, heart, and skeletal muscle citrate synthase activity (CSA) and were measured during this transition to endothermy in chickens incubated in normoxia and hypoxia (15% O2). The only significant differences in occurred in 48 hour old hatchlings where was lower in normoxic hatchlings. There were no differences in CS activity between age and incubation oxygen levels. Additionally, preliminary 2-D protein gels of embryo and hatchling liver show changes in the proteome upon hatching. Results suggest that hypoxia had no significant effect on CSA and a minimal effect on .

The purpose of this study was to compare physiological variables (i.e. oxygen consumption, blood lactate, heart rate, respiratory exchange ratio) during exercise on a double poling ergometer modified for sit skiers to a field test for the same skiers. Three male and four female athletes from the Canadian National / Developmental team (17-54 years of age, ranging in ability from a complete T7 spinal injury to cerebral palsy) completed a field test and a double poling ergometer protocol separated by at least 24 hours. Both protocols consisted of three maximal sets of skiing of three minutes duration per set separated by approximately one and a half minutes rest. A wireless metabolic system (Sensormedics, VmaxST or Cosmed, K4b2) and heart rate monitor were used to measure physiological responses during each test. Arterialized blood lactate was measured before and after each set and for 15 minutes post exercise. There were no significant differences between the field and ergometer tests for peak oxygen consumption (VO2 peak) (field=35±6 mL/kg/min vs. ergometer=33±7 mL/kg/min; p=0.491). However, significantly higher peak heart rate (field=173±5 bpm vs. ergometer=178±4 bpm; p=0.046) and respiratory exchange ratio (RER) (field=1.2±0.1 vs. ergometer=1.4±0.1; p=0.022) were found during the double poling ergometer protocol. There were no significant differences in blood lactate at baseline and after set one between protocols. However, a significantly higher lactate was found after set two (field=7±4 mmol/L vs. ergometer=12±5 mmol/L; p<0.001) and set three (field=8±3 mmol/L vs. ergometer=13±4 mmol/L; p=0.001) during the ergometer protocol compared to the field test. There were moderate correlations between the field and double poling ergometer for VO2 peak (r=0.79; p=0.035), and peak blood lactate (r=0.83; p=0.02). However, no correlations were found between protocols for peak heart rate (r=0.37; p=0.491) and RER (r=0.54; p=0.207). Results of this study suggest that the double poling ergometer is similar to a field test for evaluating VO2 peak in elite cross country sit skiing athletes; however, the ergometer test involves a higher heart rate and anaerobic component.

The purpose of this study was to compare physiological variables (i.e. oxygen consumption, blood lactate, heart rate, respiratory exchange ratio) during exercise on a double poling ergometer modified for sit skiers to a field test for the same skiers. Three male and four female athletes from the Canadian National / Developmental team (17-54 years of age, ranging in ability from a complete T7 spinal injury to cerebral palsy) completed a field test and a double poling ergometer protocol separated by at least 24 hours. Both protocols consisted of three maximal sets of skiing of three minutes duration per set separated by approximately one and a half minutes rest. A wireless metabolic system (Sensormedics, VmaxST or Cosmed, K4b2) and heart rate monitor were used to measure physiological responses during each test. Arterialized blood lactate was measured before and after each set and for 15 minutes post exercise. There were no significant differences between the field and ergometer tests for peak oxygen consumption (VO2 peak) (field=35±6 mL/kg/min vs. ergometer=33±7 mL/kg/min; p=0.491). However, significantly higher peak heart rate (field=173±5 bpm vs. ergometer=178±4 bpm; p=0.046) and respiratory exchange ratio (RER) (field=1.2±0.1 vs. ergometer=1.4±0.1; p=0.022) were found during the double poling ergometer protocol. There were no significant differences in blood lactate at baseline and after set one between protocols. However, a significantly higher lactate was found after set two (field=7±4 mmol/L vs. ergometer=12±5 mmol/L; p<0.001) and set three (field=8±3 mmol/L vs. ergometer=13±4 mmol/L; p=0.001) during the ergometer protocol compared to the field test. There were moderate correlations between the field and double poling ergometer for VO2 peak (r=0.79; p=0.035), and peak blood lactate (r=0.83; p=0.02). However, no correlations were found between protocols for peak heart rate (r=0.37; p=0.491) and RER (r=0.54; p=0.207). Results of this study suggest that the double poling ergometer is similar to a field test for evaluating VO2 peak in elite cross country sit skiing athletes; however, the ergometer test involves a higher heart rate and anaerobic component.

Thesis (M.S.)--East Carolina University, 2009. / Presented to the faculty of the Department of Exercise and Sport Science. Advisor: Timothy P. Gavin. Title from PDF t.p. (viewed June 4, 2010). Includes bibliographical references.

Thesis (M.S.)--Eastern Illinois University, 1987. / Includes bibliographical references (leaves 27-28).

No description available.

Thesis (M.S.)--Virginia Commonwealth University, 2008. / Prepared for: Dept. of Physiology and Biophysics. Title from title-page of electronic thesis. Bibliography: leaves 55-58.

Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Pomacea bridgesii is a snail species native to tropical and sub-tropical regions, where it usually faces variability in water, temperature and oxygen level. This study of the effect of temperature on mass-specific oxygen consumption (ṀO2) and its relation to body weight shows that the ṀO2 of juvenile snails in normoxia (18-21 kPa) acclimated at temperature of 25°C ranged from 5 to 58 µMol O2/g/h, with a mean of 41.4 ± 18.3 µMol O2/g/h (n=7). Adult snails in normoxia at 25°C show less variation, ranging from 13 to 23 µMol O2/g/h , with a mean of 24.4± 6.1 µMol O2/g/h (n=12). The Q10 value for juvenile snails was higher in the interval 25-30°C (Q 10=5.74) than in the interval 20-25°C (Q10= 0.286). In adult snails, Q10 was higher in the interval 20-25°C (Q10=3.19). ṀO2 of P. bridgesii in relation to body weight showed a negative linear correlation between metabolic rate and body weight with b values between 0.23 and 0.76. Also, both juvenile and adult snails exhibited weak O2 regulation. In general, the different respiratory characteristics between juvenile and adult snails might be related to the differences of individual life history, which caused them to perform differently in face of temperatures change. Additionally, Pomacean snails species originated in tropical habitats where there is a lack of thermal fluctuation. For this reason, Pomacean snails may be less likely to have evolved effective thermal acclimation capabilities.