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Effects of aging and exercise training on structural and vasoconstrictor properties of skeletal muscle arteriolesDonato, Anthony John 15 November 2004 (has links)
Aging is associated with increases in regional and systemic vascular resistance and arterial blood pressure. One possible mechanism through which these age-associated alterations occur is enhanced vasoconstrictor responsiveness, or alterations in the structural properties of the resistance vasculature. We hypothesized that stiffness and vasoconstriction would be greater in skeletal muscle arterioles from old rats, and that endurance exercise training would ameliorate the associated with aging alterations. METHODS: Young sedentary (YS; 4 months), old sedentary (OS; 24 months), young trained (YT) and old trained (OT) male Fischer 344 rats were used. Training modality was treadmill exercise at 15 m/min up a 15o incline, 5 days/wk for 12wks. Skeletal muscle first-order arterioles were isolated for in vitro experimentation. Intraluminal diameter was measured in response to the cumulative addition of endothelin-1, norepinephrine, KCl, and isoproterenol. Stiffness was measure by examining the arterioles' stress and strain relation to increased luminal pressure in Ca++ free solution. RESULTS: Skeletal muscle arterioles had augmented vasoconstriction to endothelin-1 and norepinephrine. Adrenergic vasodilation was diminished in aged rat arterioles. Stiffness increased with age. Exercise training ameliorated the age-associated changes in stiffness and norepinephrine vasoconstriction. Exercise training did not alter endothelin-1 vasoconstriction or adrenergic vasodilation. CONCLUSIONS: These findings suggest that enhanced vascular sensitivity to vasoconstrictors and increased arteriole stiffness may play a role in the increase in skeletal muscle and systemic vascular resistance and, thus, contribute to the elevated blood pressure which occurs in aging humans. These results also demonstrate some of the cardioprotective effects of exercise training.
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Benefits and constraints associated with the use of an urban park reproted by the elderly in Hong KongHung, Kam 12 April 2006 (has links)
The purpose of this study was to identify benefits and constraints associated with
the use of urban parks by a sample of elderly in Hong Kong. Before studying these topics,
self-perception of aging of the elderly in Hong Kong was explored. In-depth interviews
were conducted with 13 individuals inside and 12 outside the Tsuen Wan Jockey Club
Tak Wah Park. Purposive sampling was used to select the sample. The interviews were
semi-structured, based on an interview guide of open-ended questions.
Results of the study suggested that although there are some differences in
explanations of aging among different countries, some aging models and theories which
have been developed in western countries can be employed to interpret the aging
phenomenon in Hong Kong. Several constraints and health-related social and
psychological benefits of attending a park were reported by the sample. Heterogeneity of
leisure constraints among different age cohorts of the elderly was found in the study.
Although similarities were found between the benefits reported in this study and those
reported in western countries, the magnitude of benefits received from visiting parks may
be different because of the different characteristics of elderly in different countries.
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Characterizing strain in the proximal rat tibia during electrical muscle stimulationVyvial, Brent Aron 17 September 2007 (has links)
Hindlimb unloading is a widely used model for studying the effects of
microgravity on a skeleton. Hindlimb unloading produces a marked loss in bone due to
increased osteoclast activity. Electrical muscle stimulation is being investigated as a
simulated resistive exercise countermeasure to attenuate this bone loss. I sought to
determine the relationship between strain measured at the antero-medial aspect of the
proximal diaphysis of tibia and plantar-flexor torque measured at the ankle during
electrical muscle stimulation as an exercise countermeasure for hindlimb unloading in
rats. A mathematical relationship between strain and torque was established for the
exercise during a 28 day period of hindlimb unloading. The strain generated during the
exercise protocol is sufficient to attenuate bone loss caused by hindlimb unloading.
Twelve six-month old Sprague-Dawley rats were implanted with uni-axial strain gages
in vivo on the antero-medial aspect of the proximal diaphysis of the left tibia. Strain and
torque were measured during electrical muscle stimulation for three time points during
hindlimb unloading (Day 0 (n=3), Day 7 (n=3), Day 21 (n=3)). Peak strain decreased
from 1,100 strain at the beginning of the study to 660 strain after 21 days of hindlimb
unloading and muscle stimulation. The peak strain rate measured during muscle
stimulation was 10,350 strain/second at the beginning and decreased to 6,670 strain/second after 21 days. The changes in strain are not significant, but the
underlying trend in strain values may indicate an increase in bone formation due to the
electrical muscle stimulation countermeasure. A mathematical model that relates
measured strain to peak eccentric torque during muscle stimulation was created to facilitate estimation of strain for future studies of electrical muscle stimulation during
hindlimb unloading.
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Osteogenic effect of electric muscle stimulation as a countermeasure during hindlimb unloadingAlcorn, Justin Dow 17 September 2007 (has links)
Rats that undergo hindlimb unloading (HU) as a simulation for space flight
experience bone changes similar to astronauts in microgravity. The purpose of this
research was to assess whether an exercise countermeasure would be effective in
preventing or mitigating bone degradation during HU. Controlled electrical muscle
stimulation was applied to the lower left hindlimb to simulate resistive exercise.
Adult 6-mo. old male rats were assigned to 3 groups of 12 each: hindlimb
unloaded (HU), aging cage control (CC), and baseline (BL). The CC group was pair-fed
to match the nutritional intake of HU animals during the 28 days of the study. The left
leg was exercised 3 days a week for the duration of the study, with the unexercised right
leg serving as a contra-lateral control. Mechanical tests were conducted to assess the
strength of cancellous bone in the proximal tibia metaphysis. Although isolated
specimens of cancellous bone are not feasible, reduced platen compression (RPC) was
employed to directly load only the cancellous core region of each specimen.
There was no significant difference in ultimate stress or elastic modulus between
BL, CC, and HU-Ex (exercised). However, HU-Ex results were dramatically and
significantly higher than HU-No Ex (contra-lateral unexercised control) for both
ultimate stress (68%) and elastic modulus (81%). It is also notable that ultimate stress
was 32% higher (but not statistically significant) for HU-Ex compared to CC. The total
bone mineral density in the tibial metaphysis was significantly larger, 11%, in the HUEx
compared to the HU-No Ex group's values. The results clearly demonstrate the
efficacy of the exercise protocol in preventing the substantial mechanical deterioration
induced by HU.
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Aging on wheels the role of age in a queer female biker community /Sheehan, Brieanne M. January 2009 (has links)
Title from second page of PDF document. Includes bibliographical references (p. 56-58).
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Quantitative studies of aging using statistical mechanics and probabilistic approachesDavid-Rus, Diana. January 2009 (has links)
Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Computational Biology and Molecular Biophysics." Includes bibliographical references.
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The embodiment of social isolation : bio-behavioral systems, pre-disease pathways, and patterns of aging /Hermes, Gretchen L. January 2003 (has links)
Thesis (Ph. D.)--University of Chicago, Department of Psychology, Committee on Human Development, December 2003. / CD-ROM reproduces p. 100-136 of dissertation. Includes bibliographical references. Also available on the Internet.
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A proteomic approach to identify biomarkers of growth hormone and aging /Ding, Juan. January 2009 (has links)
Thesis (Ph.D.)--Ohio University, August, 2009. / Release of full electronic text on OhioLINK has been delayed until September 1, 2012. Includes bibliographical references (p. 253-288)
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A proteomic approach to identify biomarkers of growth hormone and agingDing, Juan. January 2009 (has links)
Thesis (Ph.D.)--Ohio University, August, 2009. / Title from PDF t.p. Release of full electronic text on OhioLINK has been delayed until September 1, 2012. Includes bibliographical references (p. 253-288)
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Age-related differences in in-vitro sensitivity to inhibition of human red blood cell (RBC) acetylcholinesterase (ACHE) and plasma butyrylcholinesterase (BUCHE) by the cholinesterase (CHE) inhibitors physostigmine (PHYS), pyridostigmine (PYR), donepezil (DON) and galantamine (GAL)Lee, David Sung, January 1900 (has links)
Thesis (Ph.D)--Virginia Commonwealth University, 2009. / Prepared for: Dept. of Pharmaceutics. Title from title-page of electronic thesis. Bibliography: leaves 249-255.
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