537 research outputs found

    Individual Values and SME Environmental Engagement

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    We study the values on which managers of small and medium-sized enterprises draw when constructing their personal and organizational-level engagement with environmental issues, particularly climate change. Values play an important mediating role in business environmental engagement but relatively little research has been conducted on individual values in smaller organizations. Using the Schwartz Value System (SVS) as a framework for a qualitative analysis, we identify four ‘ideal-types’ of SME managers and provide rich descriptions of the ways in which values shape their constructions of environmental engagement. In contrast to previous research, which is framed around a binary divide between self-enhancing and self-transcending values, our typology distinguishes between individuals drawing primarily on Power or on Achievement values, and indicates how a combination of Achievement and Benevolence values is particularly significant in shaping environmental engagement. This demonstrates the theoretical usefulness of focusing on a complete range of values. Implications for policy and practice are discussed

    Metabolic Changes Following a 1-Year Diet and Exercise Intervention in Patients With Type 2 Diabetes

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    Objective—To characterize the relationships among longterm improvements in peripheral insulin sensitivity (glucose disposal rate [GDR]), fasting glucose, and free fatty acids (FFAs) and concomitant changes in weight and adipose tissue mass and distribution induced by lifestyle intervention in obese individuals with type 2 diabetes. Research Design And Methods—We measured GDR, fasting glucose, and FFAs during a euglycemic clamp and adipose tissue mass and distribution, organ fat, and adipocyte size by dual-energy X-ray absorptiometry, CT scan, and adipose tissue biopsy in 26 men and 32 women in the Look-AHEAD trial before and after 1 year of diet and exercise aimed at weight loss. Results—Weight and fasting glucose decreased significantly (P _ 0.0001) and significantly more in men than in women (_12 vs. _8% and _16 vs. _7%, respectively; P _ 0.05), while FFAs during hyperinsulinemia decreased and GDR increased significantly (P _ 0.00001) and similarly in both sexes (_53 vs. _41% and 63 vs. 43%; P _ NS). Men achieved a more favorable fat distribution by losing more from upper compared with lower and from deeper compared with superficial adipose tissue depots (P _ 0.01). Decreases in weight and adipose tissue mass predicted improvements in GDR but not in fasting glucose or fasting FFAs; however, decreases in FFAs during hyperinsulinemia significantly determined GDR improvements. Hepatic fat was the only regional fat measure whose change contributed independently to changes in metabolic variables. Conclusions—Patients with type 2 diabetes undergoing a 1-year lifestyle intervention had significant improvements in GDR, fasting glucose, FFAs and adipose tissue distribution. However, changes in overall weight (adipose tissue mass) and hepatic fat were the most important determinants of metabolic improvements.Jeanine B. Albu, Leonie K. Heilbronn, David E. Kelley, Steven R. Smith, Koichiro Azuma, Evan S. Berk, F. Xavier Pi-Sunyer, Eric Ravussin, and the Look AHEAD Adipose Research Grou

    Kyphosis and paraspinal muscle composition in older men: a cross-sectional study for the osteoporotic fractures in men (MrOS) research group

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    BACKGROUND: The prevalence of hyperkyphosis is increased in older men; however, risk factors other than age and vertebral fractures are not well established. We previously reported that poor paraspinal muscle composition contributes to more severe kyphosis in a cohort of both older men and women. METHODS: To specifically evaluate this association in older men, we conducted a cross-sectional study to evaluate the association of paraspinal muscle composition and degree of thoracic kyphosis in an analytic cohort of 475 randomly selected participants from the Osteoporotic Fractures in Men (MrOS) study with baseline abdominal quantitative computed tomography (QCT) scans and plain thoracic radiographs. Baseline abdominal QCT scans were used to obtain abdominal body composition measurements of paraspinal muscle and adipose tissue distribution. Supine lateral spine radiographs were used to measure Cobb angle of kyphosis. We examined the linear association of muscle volume, fat volume and kyphosis using loess plots. Multivariate linear models were used to investigate the association between muscle and kyphosis using total muscle volume, as well as individual components of the total muscle volume, including adipose and muscle compartments alone, controlling for age, height, vertebral fractures, and total hip bone mineral density (BMD). We examined these associations among those with no prevalent vertebral fracture and those with BMI < 30 kg/m(2). RESULTS: Among men in the analytic cohort, means (SD) were 74 (SD = 5.9) years for age, and 37.5 (SD = 11.9) degrees for Cobb angle of kyphosis. Men in the lowest tertile of total paraspinal muscle volume had greater mean Cobb angle than men in the highest tertile, although test of linear trend across tertiles did not reach statistical significance. Neither lower paraspinal skeletal muscle volume (p-trend = 0.08), or IMAT (p-trend = 0.96) was associated with greater kyphosis. Results were similar among those with no prevalent vertebral fractures. However, among men with BMI < 30 kg/m(2), those in the lowest tertile of paraspinal muscle volume had greater adjusted mean kyphosis (40.0, 95% CI: 37.8 – 42.1) compared to the highest tertile (36.3, 95% CI: 34.2 – 38.4). CONCLUSIONS: These results suggest that differences in body composition may potentially influence kyphosis

    Dual-Energy X-Ray Absorptiometry for Quantification of Visceral Fat

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    Obesity is the major risk factor for metabolic syndrome and through it diabetes as well as cardiovascular disease. Visceral fat (VF) rather than subcutaneous fat (SF) is the major predictor of adverse events. Currently, the reference standard for measuring VF is abdominal X-ray computed tomography (CT) or magnetic resonance imaging (MRI), requiring highly used clinical equipment. Dual-energy X-ray absorptiometry (DXA) can accurately measure body composition with high-precision, low X-ray exposure, and short-scanning time. The purpose of this study was to validate a new fully automated method whereby abdominal VF can be measured by DXA. Furthermore, we explored the association between DXA-derived abdominal VF and several other indices for obesity: BMI, waist circumference, waist-to-hip ratio, and DXA-derived total abdominal fat (AF), and SF. We studied 124 adult men and women, aged 18–90 years, representing a wide range of BMI values (18.5–40 kg/m2) measured with both DXA and CT in a fasting state within a one hour interval. The coefficient of determination (r2) for regression of CT on DXA values was 0.959 for females, 0.949 for males, and 0.957 combined. The 95% confidence interval for r was 0.968 to 0.985 for the combined data. The 95% confidence interval for the mean of the differences between CT and DXA VF volume was −96.0 to −16.3 cm3. Bland–Altman bias was +67 cm3 for females and +43 cm3 for males. The 95% limits of agreement were −339 to +472 cm3 for females and −379 to +465 cm3 for males. Combined, the bias was +56 cm3 with 95% limits of agreement of −355 to +468 cm3. The correlations between DXA-derived VF and BMI, waist circumference, waist-to-hip ratio, and DXA-derived AF and SF ranged from poor to modest. We conclude that DXA can measure abdominal VF precisely in both men and women. This simple noninvasive method with virtually no radiation can therefore be used to measure VF in individual patients and help define diabetes and cardiovascular risk

    Remodeling Lipid Metabolism and Improving Insulin Responsiveness in Human Primary Myotubes

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    OBJECTIVE: Disturbances in lipid metabolism are strongly associated with insulin resistance and type 2 diabetes (T2D). We hypothesized that activation of cAMP/PKA and calcium signaling pathways in cultured human myotubes would provide further insight into regulation of lipid storage, lipolysis, lipid oxidation and insulin responsiveness. METHODS: Human myoblasts were isolated from vastus lateralis, purified, cultured and differentiated into myotubes. All cells were incubated with palmitate during differentiation. Treatment cells were pulsed 1 hour each day with forskolin and ionomycin (PFI) during the final 3 days of differentiation to activate the cAMP/PKA and calcium signaling pathways. Control cells were not pulsed (control). Mitochondrial content, (14)C lipid oxidation and storage were measured, as well as lipolysis and insulin-stimulated glycogen storage. Myotubes were stained for lipids and gene expression measured. RESULTS: PFI increased oxidation of oleate and palmitate to CO(2) (p<0.001), isoproterenol-stimulated lipolysis (p = 0.01), triacylglycerol (TAG) storage (p<0.05) and mitochondrial DNA copy number (p = 0.01) and related enzyme activities. Candidate gene and microarray analysis revealed increased expression of genes involved in lipolysis, TAG synthesis and mitochondrial biogenesis. PFI increased the organization of lipid droplets along the myofibrillar apparatus. These changes in lipid metabolism were associated with an increase in insulin-mediated glycogen storage (p<0.001). CONCLUSIONS: Activation of cAMP/PKA and calcium signaling pathways in myotubes induces a remodeling of lipid droplets and functional changes in lipid metabolism. These results provide a novel pharmacological approach to promote lipid metabolism and improve insulin responsiveness in myotubes, which may be of therapeutic importance for obesity and type 2 diabetes

    Alterations in Skeletal Muscle Fatty Acid Handling Predisposes Middle-Aged Mice to Diet-Induced Insulin Resistance

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    OBJECTIVE-Although advanced age is a risk factor for type 2 diabetes, a clear understanding of the changes that occur during middle age that contribute to the development of skeletal muscle insulin resistance is currently lacking. Therefore, we sought to investigate how middle age impacts skeletal muscle fatty acid handling and to determine how this contributes to the development of diet-induced insulin resistance. RESEARCH DESIGN AND METHODS-Whole-body and skeletal muscle insulin resistance were studied in young and middle-aged wild-type and CD36 knockout (KO) mice fed either a standard or a high-fat diet for 12 weeks. Molecular signaling pathways, intramuscular triglycerides accumulation, and targeted metabolomics of in vivo mitochondrial substrate flux were also analyzed in the skeletal muscle of mice of all ages. RESULTS-Middle-aged mice fed a standard diet demonstrated an increase in intramuscular triglycerides without a concomitant increase in insulin resistance. However, middle-aged mice fed a high-fat diet were more susceptible to the development of insulin resistance a condition that could be prevented by limiting skeletal muscle fatty acid transport and excessive lipid accumulation in middle-aged CD36 KO mice. CONCLUSION-Our data provide insight into the mechanisms by which aging becomes a risk factor for the development of insulin resistance. Our data also demonstrate that limiting skeletal muscle fatty acid transport is an effective approach for delaying the development of age-associated insulin resistance and metabolic disease during exposure to a high-fat diet. Diabetes 59:1366-1375, 201

    Association of Accelerometry-Measured Physical Activity and Cardiovascular Events in Mobility-Limited Older Adults: The LIFE (Lifestyle Interventions and Independence for Elders) Study.

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    BACKGROUND:Data are sparse regarding the value of physical activity (PA) surveillance among older adults-particularly among those with mobility limitations. The objective of this study was to examine longitudinal associations between objectively measured daily PA and the incidence of cardiovascular events among older adults in the LIFE (Lifestyle Interventions and Independence for Elders) study. METHODS AND RESULTS:Cardiovascular events were adjudicated based on medical records review, and cardiovascular risk factors were controlled for in the analysis. Home-based activity data were collected by hip-worn accelerometers at baseline and at 6, 12, and 24&nbsp;months postrandomization to either a physical activity or health education intervention. LIFE study participants (n=1590; age 78.9±5.2 [SD] years; 67.2% women) at baseline had an 11% lower incidence of experiencing a subsequent cardiovascular event per 500&nbsp;steps taken per day based on activity data (hazard ratio, 0.89; 95% confidence interval, 0.84-0.96; P=0.001). At baseline, every 30&nbsp;minutes spent performing activities ≥500&nbsp;counts per minute (hazard ratio, 0.75; confidence interval, 0.65-0.89 [P=0.001]) were also associated with a lower incidence of cardiovascular events. Throughout follow-up (6, 12, and 24&nbsp;months), both the number of steps per day (per 500&nbsp;steps; hazard ratio, 0.90, confidence interval, 0.85-0.96 [P=0.001]) and duration of activity ≥500&nbsp;counts per minute (per 30&nbsp;minutes; hazard ratio, 0.76; confidence interval, 0.63-0.90 [P=0.002]) were significantly associated with lower cardiovascular event rates. CONCLUSIONS:Objective measurements of physical activity via accelerometry were associated with cardiovascular events among older adults with limited mobility (summary score &gt;10 on the Short Physical Performance Battery) both using baseline and longitudinal data. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT01072500

    Differential effects of saturated versus unsaturated dietary fatty acids on weight gain and myocellular lipid profiles in mice

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    OBJECTIVE: In conditions of continuous high-fat (HF) intake, the degree of saturation of the fatty acids (FAs) in the diet might have a crucial role in the onset of obesity and its metabolic complications. In particular, the FA composition of the diet might influence the storage form of lipids inside skeletal muscle. The aim of the present study was to examine whether the FA composition of HF diets differentially affects weight gain and accumulation of myocellular triacylglycerol (TAG) and diacylglycerol (DAG). Furthermore, we examined whether the FA composition of the diet was reflected in the composition of the myocellular lipid intermediates.DESIGN: C57Bl6 mice were fed HF diets (45% energy) mainly containing palm oil (PO), cocoa butter (CB), olive oil (OO) or safflower oil (SO; n=6 per group) for 8 weeks. A low-fat diet (10% energy, PO) was used as control. Body weight was monitored weekly. At the end of the dietary intervention, myocellular TAG and DAG content and profiles were measured.RESULTS: We here show that HF_CB prevented weight gain after 8 weeks of HF feeding. Furthermore, the HF diet rich in SO prevented the accumulation of both myocellular TAG and DAG. Interestingly, the FA composition of DAG and TAG in skeletal muscle was a reflection of the dietary FA composition.CONCLUSION: Already after a relatively short period, the dietary FA intake relates to the FA composition of the lipid metabolites in the muscle. A diet rich in polyunsaturated FAs seems to prevent myocellular lipid accumulation.<br/

    Neck circumference is associated with adipose tissue content in thigh skeletal muscle in overweight and obese premenopausal women

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    Neck circumference (NC) has been proposed as a simple and practical tool, independently associated with cardiometabolic risk factors. However, the association of NC with inter-muscular adipose tissue (IMAT) is still to be determined. We aimed to examine the association of NC with thigh IMAT, and visceral adipose tissue (VAT) measured with computed tomography (CT) in overweight/obese women. 142 premenopausal overweight and obese Caucasian women participated in this crosssectional study. NC was measured with an inextensible metallic tape above the thyroid cartilage according to International Society for Advancement of Kinanthropometry protocol. Thigh IMAT and VAT volumes were measured with a single cross-sectional CT. Regarding the covariates, fat mass (FM) was assessed with dual-energy x-ray absorptiometry and physical activity was objectively measured with accelerometry. NC was positively associated with thigh IMAT and VAT volumes (standardized β coefcient: β=0.45, P-value= ≤0.001, β=0.60, P=≤0.001; respectively), which persisted after adjusting for age, height, overall FM or moderate-to-vigorous physical activity. Our fndings show that NC is associated with thigh IMAT volume in overweight and obese premenopausal Caucasian women, regardless of the amount of lower-body fatness. These results suggest underscoring the relevance of NC as a marker of adipose tissue content in thigh skeletal muscle.Portuguese Foundation for Science and Technology Sapiens 358007/99Oeiras City CouncilBecel PortugalRoche Pharmaceuticals PortugalCompal PortugalUniversity of Granada Plan Propio de Investigacion 2016 -Excellence actions: Unit of Excellence on Exercise and Health (UCEES)Junta de AndaluciaEuropean Union (EU) SOMM17/6107/UGRFundacion Carolina C.201657496
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