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Search Results: 1 - 10 of 465290 matches for " Roger A. Fielding "
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Serum Glycine Is Associated with Regional Body Fat and Insulin Resistance in Functionally-Limited Older Adults
Michael S. Lustgarten, Lori Lyn Price, Edward M. Phillips, Roger A. Fielding
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0084034
Abstract: Background Metabolic profiling may provide insight into biologic mechanisms related to age-related increases in regional adiposity and insulin resistance. Objectives The objectives of the current study were to characterize the association between mid-thigh intermuscular and subcutaneous adipose tissue (IMAT, SCAT, respectively) and, abdominal adiposity with the serum metabolite profile, to identify significant metabolites as further associated with the homeostasis model assessment of insulin resistance (HOMA-IR), and, to develop a HOMA-IR associated metabolite predictor set representative of regional adiposity, in 73 functionally-limited (short physical performance battery ≤10; SPPB) older adults (age range, 70–85 y). Methods Fasting levels of 181 total metabolites, including amino acids, fatty acids and acylcarnitines were measured with use of an untargeted mass spectrometry-based metabolomic approach. Multivariable-adjusted linear regression was used in all analyses. Results Thirty-two, seven and one metabolite(s) were found to be associated with IMAT, abdominal adiposity and, SCAT, respectively, including the amino acid glycine, which was positively associated with SCAT and, negatively associated with both IMAT and abdominal adiposity. Glycine and four metabolites found to be significantly associated with regional adiposity were additionally associated with HOMA-IR. Separate stepwise regression models identified glycine as a HOMA-IR associated marker of both IMAT (model R2 = 0.51, p<0.0001) and abdominal adiposity (model R2 = 0.41, p<0.0001). Conclusion Our findings for a positive association between glycine with SCAT but, a negative association between glycine with IMAT and abdominal adiposity supports the hypothesis that SCAT metabolic processes are different from that found in other fat depots. In addition, because of the significant associations found between glycine with HOMA-IR, IMAT, SCAT and abdominal adiposity, our results suggest glycine as a serum biomarker of both insulin sensitivity and regional fat mass in functionally-limited older adults.
Evaluation of the late life disability instrument in the lifestyle interventions and independence for elders pilot (LIFE-P) study
Fang-Chi Hsu, W Jack Rejeski, Edward H Ip, Jeff A Katula, Roger Fielding, Alan M Jette, Stephanie A Studenski, Steven N Blair, Michael E Miller
Health and Quality of Life Outcomes , 2010, DOI: 10.1186/1477-7525-8-115
Abstract: LIFE-P participants, aged 70-89 years, were at elevated risk of disability. The 424 participants were enrolled at the Cooper Institute, Stanford University, University of Pittsburgh, and Wake Forest University. Physical activity and successful aging health education interventions were compared after 12-months of follow-up. Using factor analysis, we determined whether the LLDI's factor structure was comparable with that reported previously. We further examined how each item related to measured disability using item response theory (IRT).The factor structure for the limitation domain within the LLDI in the LIFE-P study did not corroborate previous findings. However, the factor structure using the abbreviated version was supported. Social and personal role factors were identified. IRT analysis revealed that each item in the social role factor provided a similar level of information, whereas the items in the personal role factor tended to provide different levels of information.Within the context of community-based clinical intervention research in aged populations, an abbreviated version of the LLDI performed better than the full 16-item version. In addition, the personal subscale would benefit from additional research using IRT.The protocol of LIFE-P is consistent with the principles of the Declaration of Helsinki and is registered at http://www.ClinicalTrials.gov webcite (registration # NCT00116194).Disability is a major focus for intervention research in aging due to the social, personal, and economic costs associated with the loss of independence [1]. The magnitude of this problem will intensify with the aging of the 'baby boom' generation. Consistent with the International classification of functioning, Disability, and Health (ICF) framework [2], disability is now conceptualized as a rubric for capturing impairments, functional limitations, and activity restrictions. Jette and his colleagues [3] have noted that most existing instruments focus on assessing discrete
Systemic Vascular Function Is Associated with Muscular Power in Older Adults
Kevin S. Heffernan,Angela Chalé,Cynthia Hau,Gregory J. Cloutier,Edward M. Phillips,Patrick Warner,Heather Nickerson,Kieran F. Reid,Jeffrey T. Kuvin,Roger A. Fielding
Journal of Aging Research , 2012, DOI: 10.1155/2012/386387
Abstract: Age-associated loss of muscular strength and muscular power is a critical determinant of loss of physical function and progression to disability in older adults. In this study, we examined the association of systemic vascular function and measures of muscle strength and power in older adults. Measures of vascular endothelial function included brachial artery flow-mediated dilation (FMD) and the pulse wave amplitude reactive hyperemia index (PWA-RHI). Augmentation index (AIx) was taken as a measure of systemic vascular function related to arterial stiffness and wave reflection. Measures of muscular strength included one repetition maximum (1RM) for a bilateral leg press. Peak muscular power was measured during 5 repetitions performed as fast as possible for bilateral leg press at 40% 1RM. Muscular power was associated with brachial FMD ( ?? = 0 . 4 3 , ?? < 0 . 0 5 ), PWA-RHI ( ?? = 0 . 4 2 , ?? < 0 . 0 5 ), and AIx ( ?? = ? 0 . 5 4 , ?? < 0 . 0 5 ). Muscular strength was not associated with any measure of vascular function. In conclusion, systemic vascular function is associated with lower-limb muscular power but not muscular strength in older adults. Whether loss of muscular power with aging contributes to systemic vascular deconditioning or vascular dysfunction contributes to decrements in muscular power remains to be determined. 1. Introduction As life expectancy in the United States continues to rise, the maintenance of physical independence of older adults has also emerged as a major clinical and public health priority. A critical factor in an older person’s ability to function independently is the ability to move without assistance. Older adults who lose mobility are less likely to remain in the community, have higher rates of mortality, and experience a poorer quality of life [1, 2]. Age-associated loss of muscular strength (the ability to generate maximal muscle force) and muscular power (the product of the force and velocity of muscle contraction) is an important determinant of this loss of physical function and progression to disability [3]. Interestingly, although muscular strength and power are associated, muscular power has been shown to be a stronger predictor of physical function than muscular strength in older adults [4, 5]. Poor muscular power is associated with a 3-fold greater risk for mobility impairment than poor muscle strength [6] and improving muscular power leads to improvements in physical function independent of changes in muscular strength [7]. Although numerous potential mechanisms have been put forth, no single common
Evaluation of the Prognostic Value of IFN-γ Release Assay and Tuberculin Skin Test in Household Contacts of Infectious Tuberculosis Cases in Senegal
Christian Lienhardt,Katherine Fielding,Abdoul A. Hane,Aliou Niang,Cheikh T. Ndao,Farba Karam,Helen Fletcher,Fatou Mbow,Jules-Fran?ois Gomis,Roger Diadhiou,Maxime Toupane,Tandakha Dieye,Souleymane Mboup
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0010508
Abstract: Chemoprophylaxis of contacts of infectious tuberculosis (TB) cases is recommended for TB control, particularly in endemic countries, but is hampered by the difficulty to diagnose latent TB infection (LTBI), classically assessed through response to the Tuberculin Skin Test (TST). Interferon-gamma release assays (IGRA) are proposed new tools to diagnose LTBI, but there are limited data on their ability to predict the development of active TB disease. To address this, we investigated the response to TST and IGRA in household contacts of infectious TB cases in a TB high-burden country and the potential correlation with development of TB.
Relation of Pulse Pressure to Long-Distance Gait Speed in Community-Dwelling Older Adults: Findings from the LIFE-P Study
Kevin S. Heffernan, Todd M. Manini, Fang-Chi Hsu, Steven N. Blair, Barbara J. Nicklas, Stephen B. Kritchevsky, Anne B. Newman, Kim Sutton-Tyrrell, Timothy S. Church, William L. Haskell, Roger A. Fielding
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0049544
Abstract: Background Reduced gait speed is associated with falls, late-life disability, hospitalization/institutionalization and cardiovascular morbidity and mortality. Aging is also accompanied by a widening of pulse pressure (PP) that contributes to ventricular-vascular uncoupling. The purpose of this study was to test the hypothesis that PP is associated with long-distance gait speed in community-dwelling older adults in the Lifestyle Interventions and Independence for Elders Pilot (LIFE-P) study. Methods Brachial blood pressure and 400-meter gait speed (average speed maintained over a 400-meter walk at “usual” pace) were assessed in 424 older adults between the ages of 70–89 yrs at risk for mobility disability (mean age = 77 yrs; 31% male). PP was calculated as systolic blood pressure (BP) – diastolic BP. Results Patients with a history of heart failure and stroke (n = 42) were excluded leaving 382 participants for final analysis. When categorized into tertiles of PP, participants within the highest PP tertile had significantly slower gait speed than those within the lowest PP tertile (p<0.05). Following stepwise multiple regression, PP was significantly and inversely associated with 400-meter gait speed (p<0.05). Other significant predictors of gait speed included: handgrip strength, body weight, age and history of diabetes mellitus (p<0.05). Mean arterial pressure, systolic BP and diastolic BP were not predictors of gait speed. Conclusions Pulse pressure is associated long-distance gait speed in community-dwelling older adults. Vascular senescence and altered ventricular-vascular coupling may be associated with the deterioration of mobility and physical function in older adults.
Successful Aging
Loretta DiPietro,Maria Fiatarone Singh,Roger Fielding,Hiroshi Nose
Journal of Aging Research , 2012, DOI: 10.1155/2012/438537
Successful Aging
Loretta DiPietro,Maria Fiatarone Singh,Roger Fielding,Hiroshi Nose
Journal of Aging Research , 2012, DOI: 10.1155/2012/438537
Mitigating Biodiversity Concerns in Eucalyptus Plantations Located in South China  [PDF]
Roger A. Williams
Journal of Biosciences and Medicines (JBM) , 2015, DOI: 10.4236/jbm.2015.36001

China’s growing economy and changes in policies that encourage afforestation, particularly in the industrial sector, have led vast areas in south China to be planted with eucalyptus. These large areas of eucalyptus plantings have elicited environmental concerns for two primary reasons. First there is a concern related to the water demand of eucalyptus, in which it is feared these large areas of eucalyptus will deplete aquifers and create shortages in water supplies. The second concern is in regard to the reduction in biodiversity across large landscapes, leading to further ecological demises. This paper proposes two ideas to possibly mitigate some of the biodiversity concerns. The first is the interplanting of alder-leaf birch (Betula alnoides), a native but dwindling species in south China, to enhance biodiversity and encourage it’s reestablishment across the landscape. The second is to encourage retention harvests of alder-leaf birch planted within eucalyptus plantations to enhance not only biological diversity but also structural diversity across the landscape. Alder-leaf birch has demonstrated great potential in producing high quality timber and wood for use in furniture manufacturing.

An Investigation of the Carbon Neutrality of Wood Bioenergy  [PDF]
Roger A. Sedjo, Xiaohui Tian
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.39114
Abstract: Wood biomass has been viewed as “carbon neutral”—its uses as energy have a zero carbon footprint. Some observers argue that the use of wood biofuels will result in a decrease of the forest stock and a net reduction of the carbon captured in the forest. Such assessments take a static, accounting view of forest systems and do not consider the effects of management in renewing the forest and increasing its extent or ability to sequester carbon. This paper addresses the carbon neutrality debate using a dynamic optimization forest management model to examine the effect on the existing and future forests of a changing demand for wood biomass. The results show that under market optimizing conditions, when future demand is anticipated to increase for significant periods, the response of managers will be to increase the intensity of forest production thereby offsetting much of the carbon released in bioenergy production.
Expanding public health professionals’ roles in promoting and supporting breastfeeding as optimal infant feeding: A pilot study with online tutorial implications  [PDF]
Amna Umer, Roger A. Edwards
Open Journal of Preventive Medicine (OJPM) , 2013, DOI: 10.4236/ojpm.2013.32025

Background: Their knowledge of preventive health, coupled with their dynamic roles in the community, puts public health professionals in a key position to expand their roles in the health promotion and support of breastfeeding as optimal infant feeding. This online tutorial was created to increase public health professionals’ knowledge about breastfeeding and to assess their attitudes in supporting healthy behaviors related to infant feeding as a health promotion strategy. Method: The study utilized an online breastfeeding tutorial based on the US Breast-feeding Committee recommendations for minimum breastfeeding knowledge for health professionals. Pre- and post-tutorial questionnaires assessed breastfeeding knowledge, and an attitudinal survey evaluated attitudes of public health professionals after the tutorial. Exposing public health students to this information can facilitate the early shaping of their attitudes and understanding about the importance of breastfeeding. Results: Fifty-two Northeastern University MPH students and alumni (62% response rate) completed the study. There was an overall gain in participants’ fundamental knowledge regarding breastfeeding as assessed by pre- (77%) to post-tutorial (97%) correct responses (p = 0.00001). The post-tutorial attitudinal survey showed that 92% of participants were comfortable in answering questions about breastfeeding as part of their professional responsibilities. Conclusion: This pilot study highlights the important role that a short online tutorial can play in expanding public health professionals’ knowledge about breastfeeding. Greater use of online methods can enhance awareness of critical health behaviors, such as breastfeeding, that have not received adequate attention in public health curricula. This pilot study provides the foundation for a larger study. Integration of breastfeeding into public health professionals’ core training could support broader social change.

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