Browsing by Subject "Behavior and Ethology"
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Item Contributions to North American Ethnology V.5 : Survey of the Rocky Mountain Region(Government Printing Office, 1882-01-01) Fletcher, Robert; Thomas, Cyrus; Brinton, D.; Rau, CharlesItem Evolution and Culture; Their Relation in the Light of Modern Ethnology(B. Herder Book Co., 1923-01-01) Muntsch, AlbertItem Mechanisms of Chemoreflex Control of Muscle Sympathetic Nerve Activity and Blood Pressure in Humans(2004-05-01) Hardisty, Janelle M.; Smith, Michael; Shi, Xiangrong; Clark, MichaelHardisty, Janelle M., Mechanisms of Chemoreflex Control of Muscle Sympathetic Nerve Activity and Blood Pressure in Humans. Doctor of Philosophy (Integrative Physiology), May 2004. The mechanisms linking obstructive sleep apnea (OSA) and cardiovascular disease are not fully understood; however, studies report patients with OSA exhibit chronic elevations in muscle sympathetic nerve activity (MSNA). This appears to be due to altered chemoreflex control of MSNA, mediated primarily by hypoxia. Yet, a correlation between degree of hypoxia and chemoreflex control of MSNA is unknown. Therefore, it was evaluated whether degree of hypoxia occurring during apnea determines the sympathoexcitatory and blood pressure responses, and whether these responses are augmented in OSA patients. Additionally, it was studied whether altered chemoreflex function in OSA patients is predictive of blood pressure response to apnea. In a clinical setting, the blood pressure response to voluntary apnea was determined to evaluate whether this could be used as a non-invasive measure of chemoreflex gain in OSA. Finally, the effect of hyperoxia on MSNA was studied to determine whether 15 min of hyperoxia, following intermittent hypoxic apnea, reverses the elevation of MSNA and altered chemoreflex control of MSNA. Consistent with the hypotheses, a relationship between MSNA responses, blood pressure response and level of hypoxia were determined. MSNA and peak systolic pressure responses were augmented in OSA subjects (p≤0.05 and p≤0.05, respectively), as well as, chemoreflex gain (p≤0.05). Clinically, peak systolic pressure responses to apnea were augmented in OSA patients (p˂0.001). Finally, basal MSNA and chemoreflex control of MSNA, following hyperoxia, was not different from baseline through 180 min of recovery (p=0.940 and p=0.278, respectively). These data support the hypotheses that chemoreflex gain is predicative of the blood pressure response; and furthermore, the MSNA and blood pressure responses to hypoxic apnea are augmented in OSA. Additionally, peak systolic pressure responses to voluntary apnea are augmented in OSA. Additionally, peak systolic pressure responses to voluntary apnea are augmented in OSA patients and could possibly be used as a marker of chemoreflex gain. Moreover, these data support the hypothesis that hyperoxia can reverse basal sympathoexcitation and augmented chemoreflex control of MSNA, associated with hypoxic apnea, supporting that elevations in MSNA are hypoxia mediated.Item On the Edge of the Primeval forest: Experiences and Observations of A Doctor in Equatorial Africa(A. & C. Black, LTD, 1922-01-01) Campion, Charles; Schweitzer, AlbertItem Rural Vs. Urban Residents and Obesity in Texas(2005-05-01) Ohagi, Emeka J.; Ty Borders; Peter Hilsenrath; Kathryn CardarelliOhagi, Emeka J., Rural vs. Urban Residents and Obesity in Texas. Master of Public Health (Health Informatics), May 2005, 52 pp., 3 tables, bibliography, 90 titles. Obesity in the United States has been described as an epidemic and Texas has been identified as one of the most obese states in the country. The purpose of this study is to examine obesity among Texas adults in order to determine if there are differences in obesity levels based on residence, and to explore the influence of other demographic, socioeconomic, health and behavioral factors on the distribution of obesity. Results indicate that urban and suburban dwellers are less likely than rural dwellers to be obese (adj. OR=0.64; 0.68, respectively). However, residents of frontier communities have slightly higher odds of obesity (adj. OR=1.09) than rural residents. Age was found to be an important factor in obesity. It is hoped that these and other results will facilitate appropriate channeling of public health response.