bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interactive Effects Between Polymorphisms in the β‐Adrenergic Receptors and Longitudinal Changes in Obesity
Authors: Ellsworth Darrell L. , Coady Sean A. , Chen Wei , Srinivasan Sathanur R. , Boerwinkle Eric , Berenson Gerald S. 
Published: April 2008

AbstractWe assessed interactions between polymorphisms in the β‐adrenergic receptor genes and longitudinal changes in obesity from childhood to adulthood using longitudinal data collected over a 24‐year period from 1973 to 1996. Sex‐ and age‐stratified analyses using random coefficients models were used to examine gene—gene interaction effects on obesity measures in 1179 African‐American and white men and women (71% white, 57% women). Suggestive evidence for an interaction (p = 0.022) between the β1‐ and β2‐adrenergic receptors was observed in men for longitudinal change in BMI. Men with Gly/Gly genotypes for both the β1 and β2 receptors showed significant increases (∼0.6%/yr) in BMI from childhood to adulthood. Women showed suggestive evidence for an interaction (p = 0.035) between the β1‐ and β3‐adrenergic receptors for change over time in BMI. Women with Gly/Gly genotypes at the β1‐receptor and carrying at least one β3‐Arg allele showed notable increases in BMI. The regulation of lipolysis and development of obesity differ markedly between men and women and may be influenced by genetic polymorphisms, which contribute to the efficiency of the β‐adrenergic receptors, and hormonal effects on adrenergic receptor activity.
Adenosinergic Modulation of Ventilation in Obese Zucker Rats
Authors: Lee Shin‐Da , Nakano Hitoshi , Farkas Gaspar A. 
Published: April 2008

AbstractObjectives: The goal of our study was to determine whether altered adenosinergic mechanisms contribute to the depressed ventilatory response observed in obese Zucker rats.Research Methods and Procedures: Eight lean and eight obese Zucker rats were studied at 7 to 8 weeks of age. Ventilation (V˙E) during room air, during 5‐minute hypercapnic (7% CO2, balance O2), and during 30‐minute sustained hypoxic (10% O2) exposures were sequentially measured by the barometric method on three separate occasions after the randomized blinded administration of equal volumes of either saline (control), 8‐(p‐sulfophenyl)‐theophylline (8‐PST, 7 mg/kg, peripheral adenosine antagonist), or aminophylline (AMPH, 15 mg/kg, peripheral and central adenosine antagonist).Results: During room air and hypercapnic exposures, AMPH (but not 8‐PST) significantly (p < 0.05) increased V˙E in both lean and obese rats. During acute (2 minute) hypoxic exposure, 8‐PST (but not AMPH) significantly depressed V˙E in lean rats. In contrast, AMPH (but not 8‐PST) selectively increased V˙E in obese rats. During sustained (10 to 30 minutes) hypoxic exposure, neither AMPH nor 8‐PST administration altered V˙E in lean rats. In contrast, AMPH (but not 8‐PST) selectively increased V˙E during the late response in obese rats.Discussion: Our findings indicate that obese rats possess altered adenosinergic modulation of ventilatory responses to acute and sustained hypoxia in two opposite ways. We conclude that the reduced hypoxic ventilatory response observed in obese Zucker rats is attributed to depressed adenosinergic peripheral excitatory mechanisms and to enhanced adenosinergic central depression mechanisms, both of which contribute to the blunted ventilatory response in obesity.
Glucose Tolerance and Skeletal Muscle Gene Expression in Response to Alternate Day Fasting
Authors: Heilbronn Leonie K. , Civitarese Anthony E. , Bogacka Iwona , Smith Steven R. , Hulver Matthew , Ravussin Eric 
Published: April 2008

AbstractObjective: Alternate day fasting may extend lifespan in rodents and is feasible for short periods in nonobese humans. The aim of this study was to examine the effects of 3 weeks of alternate day fasting on glucose tolerance and skeletal muscle expression of genes involved in fatty acid transport/oxidation, mitochondrial biogenesis, and stress response.Research Methods and Procedures: Glucose and insulin responses to a standard meal were tested in nonobese subjects (eight men and eight women; BMI, 20 to 30 kg/m2) at baseline and after 22 days of alternate day fasting (36 hour fast). Muscle biopsies were obtained from a subset of subjects (n = 11) at baseline and on day 21 (12‐hour fast).Results: Glucose response to a meal was slightly impaired in women after 3 weeks of treatment (p < 0.01), but insulin response was unchanged. However, men had no change in glucose response and a significant reduction in insulin response (p < 0.03). There were no significant changes in the expression of genes involved in mitochondrial biogenesis or fatty acid transport/oxidation, although a trend toward increased CPT1 expression was observed (p < 0.08). SIRT1 mRNA expression was increased after alternate day fasting (p = 0.01).Discussion: Alternate day fasting may adversely affect glucose tolerance in nonobese women but not in nonobese men. The gene expression results indicate that fatty acid oxidation and mitochondrial biogenesis are unaffected by alternate day fasting. However, the increased expression in SIRT1 suggests that alternate day fasting may improve stress resistance, a commonly observed feature of calorie‐restricted rodents.
Sedentary Behavior, Physical Activity, and the Metabolic Syndrome among U.S. Adults
Authors: Ford Earl S. , Kohl Harold W. , Mokdad Ali H. , Ajani Umed A. 
Published: April 2008

AbstractObjective: We examined the associations among physical activity, sedentary behavior, and metabolic syndrome in a representative sample of U.S. adults.Research Methods and Procedures: A total of 1626 men and women ≥20 years old from National Health and Nutrition Examination Survey 1999 to 2000 who attended the morning examination were evaluated. The metabolic syndrome was defined by using the definition from the National Cholesterol Education Program.Results: In unadjusted analysis, participants who did not engage in any moderate or vigorous physical activity during leisure time had almost twice the odds of having metabolic syndrome [odds ratio (OR), 1.90; 95% confidence interval (CI), 1.22 to 2.97] as those who reportedly engaged in ≥150 min/wk of such activity. Adjustment for age, sex, race or ethnicity, educational status, smoking status, and alcohol use attenuated the OR (OR, 1.46; 95% CI, 0.87 to 2.45). Compared with participants who watched television or videos or used a computer <1 h/d outside of work, the adjusted ORs for having metabolic syndrome were 1.41 (95% CI 0.80 to 2.51) for 1 h/d, 1.37 (95% CI 0.85 to 2.20) for 2 h/d, 1.70 (95% CI 0.92 to 3.14) for 3 h/d, and 2.10 (95% CI 1.27 to 3.47) for ≥4 h/d. Additional adjustment for physical activity or sedentary behavior minimally affected the ORs.Discussion: Sedentary behavior is an important potential determinant of the prevalence of the syndrome. Efforts to lessen the amount of time that U.S. adults spend watching television or videos or using a computer, especially if coupled to increases in physical activity, could result in substantial decreases in the prevalence of metabolic syndrome.
Effects of Exercise on Metabolic Risk Variables in Overweight Postmenopausal Women: A Randomized Clinical Trial
Authors: Frank Laura Lewis , Sorensen Bess E. , Yasui Yutaka , Tworoger Shelley S. , Schwartz Robert S. , Ulrich Cornelia M. , Irwin Melinda L. , Rudolph Rebecca E. , Rajan Kumar B. , Stanczyk Frank , Bowen Deborah , Weigle David S. , Potter John D. , McTiernan Anne 
Published: April 2008

AbstractObjective: This study examined the effects of exercise on metabolic risk variables insulin, leptin, glucose, and triglycerides in overweight/obese postmenopausal women.Research Methods and Procedures: Sedentary women (n = 173) who were overweight or obese (BMI ≥ 25 kg/m2 or ≥24 kg/m2 with ≥33% body fat), 50 to 75 years of age, were randomized to 12 months of exercise (≥45 minutes of moderate‐intensity aerobic activity 5 d/wk) or to a stretching control group. Body composition (DXA) and visceral adiposity (computed tomography) were measured at baseline and 12 months. Insulin, glucose, triglycerides, and leptin were measured at baseline and 3 and 12 months. Insulin resistance was evaluated by the homeostasis model assessment formula. Differences from baseline to follow‐up were calculated and compared across groups.Results: Exercisers had a 4% decrease and controls had a 12% increase in insulin concentrations from baseline to 12 months (p = 0.0002). Over the same 12‐month period, leptin concentrations decreased by 7% among exercisers compared with remaining constant among controls (p = 0.03). Homeostasis model assessment scores decreased by 2% among exercisers and increased 14% among controls from baseline to 12 months (p = 0.0005). The exercise effect on insulin was modified by changes in total fat mass (trend, p = 0.03), such that the exercise intervention abolished increases in insulin concentrations associated with gains in total fat mass.Discussion: Regular moderate‐intensity exercise can be used to improve metabolic risk variables such as insulin and leptin in overweight/obese postmenopausal women. These results are promising for health care providers providing advice to postmenopausal women for lifestyle changes to reduce risk of insulin resistance, coronary heart disease, and diabetes.
Neuropeptides, Including Neuropeptide Y and Melanocortins, Mediate Lipolysis in Murine Adipocytes
Authors: Bradley Richard L. , Mansfield Julia P. R. , Maratos‐Flier Eleftheria 
Published: April 2008

AbstractObjective: To determine whether key appetite‐regulating neuropeptides such as melanin‐concentrating hormone (MCH), neuropeptide Y (NPY), and α‐melanocyte—stimulating hormone (α‐MSH), which are known to mediate energy balance through centrally mediated pathways, also have direct acute effects on the lipolytic activity of murine adipocytes.Research Methods and Procedures: Fully differentiated 3T3‐L1 adipocytes serum starved overnight in Dulbecco's modified Eagle medium containing 2% bovine serum albumin or freshly isolated mouse adipocytes were incubated for up to 2 hours in the absence and presence of 100 nM each of NPY, MCH, α‐MSH, the melanocortin receptor agonist MTII, or isoproterenol as a control. Free fatty acids secreted into the incubation medium were measured using a commercially available nonesterified fatty acid C test kit.Results: Treatment of 3T3‐L1 cells with 100 nM NPY decreased basal free fatty acid secretion (basal, 0.006 ± 0.001 vs. NPY, 0.001 ± 0.0003 nM at 90 minutes; p < 0.05), whereas both α‐MSH and MTII stimulated up to a 7‐fold increase in free fatty acid release (MTII, 0.238 ± 0.004 vs. basal, 0.024 ± 0.002 nM at 2 hours; p < 0.05; and α‐MSH, 0.22 ± 0.005 vs. basal, 0.04 ± 0.003 nM at 2 hours; p < 0.05). Treatment with 100 nM MCH had no effect on basal free fatty acid release or on α‐MSH—induced lipolysis during concurrent treatment. Conversely, concurrent treatment with 100 nM NPY dramatically inhibited (by ∼90%) α‐MSH—induced lipolysis. Similar treatment of freshly isolated mouse adipocytes showed virtually identical results.Discussion: In addition to their centrally mediated actions, appetite‐regulating neuropeptides modulate adipose tissue mass through direct peripheral effects. Systemic administration of pharmacological agents altering the effects of these neuropeptides may form the basis of future obesity therapies. Thus, some of these agents will likely have direct effects on adipocytes that may serve to alter their therapeutic effectiveness.
Regulation of Adiponectin Expression in Human Adipocytes: Effects of Adiposity, Glucocorticoids, and Tumor Necrosis Factor α
Authors: Degawa‐Yamauchi Mikako , Moss Katherine A. , Bovenkerk Jason E. , Shankar Sudha S. , Morrison Charles L. , Lelliott Christopher J. , Vidal‐Puig Antonio , Jones RoseMarie , Considine Robert V. 
Published: April 2008

AbstractObjective: Adiponectin mRNA expression in isolated subcutaneous and omental adipocytes was examined across a wide range of adiposity to determine whether adiponectin synthesis is impaired in these adipose tissue depots in obese humans. Tumor necrosis factor (TNF)α and dexamethasone were tested for inhibitory effects on adiponectin release from human adipocytes in vitro.Research Methods and Procedures: Adipocytes were isolated by collagenase digestion of abdominal adipose tissue obtained from subjects undergoing surgical procedures or outpatient needle biopsy. Adiponectin and leptin mRNA were quantitated by real‐time reverse transcriptase‐polymerase chain reaction. Adiponectin and leptin secretion from isolated adipocytes treated with dexamethasone or TNFα were determined by radioimmunoassay.Results: There was a significant negative correlation between adiponectin gene expression and BMI in subcutaneous adipocytes from 32 women (r = 0.420; p = 0.02). Adiponectin mRNA was also significantly correlated with serum adiponectin (r = 0.44; p = 0.03; n = 25). There was no correlation between adiponectin mRNA expression and BMI in omental adipocytes from 29 women. Leptin mRNA was significantly and positively correlated (r = 0.484; p = 0.01) with BMI in the same omental adipocyte mRNA preparations. In subcutaneous adipocytes from lean subjects, TNFα inhibited adiponectin release by 7.4 ± 1.2% (n = 9, p < 0.05) but had no effect on adiponectin release from subcutaneous or omental adipocytes from obese subjects. Dexamethasone significantly inhibited adiponectin release with 24 hours of treatment.Discussion: The data suggest that reduced adiponectin synthesis in subcutaneous adipocytes contributes to lower serum adiponectin levels in obesity and that glucocorticoids regulate adiponectin gene expression in human adipocytes. TNFα does not seem to directly inhibit adiponectin synthesis in human adipocytes.
Intentional Weight Loss Reduces Mortality Rate in a Rodent Model of Dietary Obesity
Authors: Vasselli Joseph R. , Weindruch Richard , Heymsfield Steven B. , Pi‐Sunyer F. Xavier , Boozer Carol N. , Yi Nengjun , Wang Chenxi , Pietrobelli Angelo , Allison David B. 
Published: April 2008

AbstractObjective: We used a rodent model of dietary obesity to evaluate effects of caloric restriction‐induced weight loss on mortality rate.Research Measures and Procedures: In a randomized parallel‐groups design, 312 outbred Sprague‐Dawley rats (one‐half males) were assigned at age 10 weeks to one of three diets: low fat (LF; 18.7% calories as fat) with caloric intake adjusted to maintain body weight 10% below that for ad libitum (AL)‐fed rat food, high fat (HF; 45% calories as fat) fed at the same level, or HF fed AL. At age 46 weeks, the lightest one‐third of the AL group was discarded to ensure a more obese group; the remaining animals were randomly assigned to one of three diets: HF‐AL, HF with energy restricted to produce body weights of animals restricted on the HF diet throughout life, or LF with energy restricted to produce the body weights of animals restricted on the LF diet throughout life. Life span, body weight, and leptin levels were measured.Results: Animals restricted throughout life lived the longest (p < 0.001). Life span was not different among animals that had been obese and then lost weight and animals that had been nonobese throughout life (p = 0.18). Animals that were obese and lost weight lived substantially longer than animals that remained obese throughout life (p = 0.002). Diet composition had no effect on life span (p = 0.52).Discussion: Weight loss after the onset of obesity during adulthood leads to a substantial increase in longevity in rats.
Decreased Glucagon‐like Peptide 1 Release after Weight Loss in Overweight/Obese Subjects
Authors: Adam Tanja C. M. , Jocken Johan , Westerterp‐Plantenga Margriet S. 
Published: April 2008

AbstractObjective: Postprandial glucagon‐like peptide 1 (GLP‐1) release seems to be attenuated in obese subjects. Results on whether weight loss improves GLP‐1 release are contradictory. The aim of this study was to further investigate the effect of weight loss on basal and postprandial GLP‐1 release in overweight/obese subjects.Research Methods and Procedures: Thirty‐two overweight/obese subjects participated in a repeated measurement design before (BMI, 30.3 ± 2.8 kg/m2; waist circumference, 92.6 ± 7.8 cm; hip circumference, 111.1 ± 7.4 cm) and after a weight loss period of 6 weeks (BMI, 28.2 ± 2.7 kg/m2; waist circumference, 85.5 ± 8.5 cm; hip circumference, 102.1 ± 9.2 cm). During weight loss, subjects received a very‐low‐calorie diet (Optifast) to replace three meals per day. Subjects came to the laboratory fasted, and after a baseline blood sample, received a standard breakfast (1.9 MJ). Postprandially, blood samples were taken every one‐half hour relative to intake for 120 minutes to determine GLP‐1, insulin, glucose, and free fatty acids from plasma. Appetite ratings were obtained with visual analog scales.Results: After weight loss, postprandial GLP‐1 concentrations at 30 and 60 minutes were significantly lower than before weight loss (p < 0.05). Glucose concentrations were also lower, and free fatty acids were higher compared with before weight loss. Ratings of satiety were increased, and hunger scores were decreased after weight loss (p < 0.05).Discussion: In overweight/obese subjects, GLP‐1 concentrations after weight loss were decreased compared with before weight loss, and nutrient‐related stimulation was abolished. This might be a response to a proceeding negative energy balance. Satiety and GLP‐1 seem to be unrelated in the long term.
Ghrelin Does Not Influence Gastric Emptying in Obese Subjects
Authors: Mora Maria E. Valera , Scarfone Antonino , Valenza Venanzio , Calvani Menotti , Greco Aldo V. , Gasbarrini Giovanni , Mingrone Geltrude 
Published: April 2008

AbstractObjective: To evaluate the relationship between fasting plasma concentrations of ghrelin and gastric emptying in obese individuals compared with lean subjects.Research Methods and Procedures: We included 20 obese patients (9 men and 11 women, BMI > 30 kg/m2) and 16 nonobese control subjects (7 men and 9 women, BMI ≤ 25 kg/m2). Gastric emptying of solids (egg sandwich labeled with radionuclide) was measured at 120 minutes with (99m)Tc‐single photon emission computed tomography imaging. Ghrelin and leptin were analyzed by radioimmunoassay and ELISA methods, respectively.Results: The gastric half‐emptying time was similar in obese men and women (67.8 ± 14.79 vs. 66.6 ± 13.56 minutes) but significantly shorter (p < 0.001) than in the control population (men: 88.09 ± 11.72 minutes; women: 97.25 ± 10.31 minutes). Ghrelin levels were significantly lower in obese subjects (131.37 ± 47.67 vs. 306.3 ± 45.52 pg/mL; p < 0.0001 in men and 162.13 ± 32.95 vs. 272.8 ± 47.77 pg/mL; p < 0.0001 in women). A negative correlation between gastric emptying and fasting ghrelin levels was observed only in lean subjects (y = −0.2391x + 157.9; R2 = 0.95). Also, in the lean group, ghrelin was the only significant independent determinant of gastric emptying, explaining 98% of the variance (adjusted R2) in a multiple regression analysis.Discussion: This report shows that, in humans, gastric emptying is faster in obese subjects than in lean controls and that, whereas ghrelin is the best determinant of gastric kinetics in healthy controls, this action is lost in obesity.
Survival Expectations of the Obese: Is Excess Mortality Reflected in Perceptions?
Authors: Falba Tracy A. , Busch Susan H. 
Published: April 2008

AbstractObjective: This study compared self‐reported subjective life expectancy (i.e., probability of living to age 75) for normal‐weight, overweight, and obese weight groups to examine whether individuals are internalizing information about the health risks due to excessive weight.Research Methods and Procedures: Using data from the Health and Retirement Study, a total of 9035 individuals 51 to 61 years old were analyzed by BMI category. The primary outcome measure was individuals’ reports about their own expectations of survival to age 75. Absolute and relative risks of survival were compared with published estimates of survival to age 75.Results: Consistently, higher levels of BMI were associated with lower self‐estimated survival probabilities. Differences relative to normal weight ranged from 4.9% (p < 0.01) for male nonsmokers to 8.8% (p < 0.001) for female nonsmokers. However, these differences were substantially less than those obtained from published survival curve estimates, suggesting that obese individuals tended to underestimate mortality risks.Discussion: Individuals appeared to underestimate the mortality risks of excessive weight; thus, knowledge campaigns about the risks of obesity should remain a top priority.
Altered Luteinizing Hormone and Testosterone Secretion in Middle‐Aged Obese Men with Obstructive Sleep Apnea
Authors: Luboshitzky Rafael , Lavie Lena , Shen‐Orr Zila , Herer Paula 
Published: April 2008

AbstractObjective: To elucidate the causes for the decline in testosterone levels observed in men with obstructive sleep apnea (OSA).Research Methods and Procedures: We determined serum luteinizing hormone (LH) and testosterone levels every 20 minutes between 7 pm and 7 am with simultaneous sleep recordings in five obese middle‐aged men with OSA, in five age‐ and BMI‐matched controls, and in six lean young healthy men.Results: The mean and area under the curve (AUC) values of LH and testosterone were significantly lower in men with OSA compared with controls. Young controls had significantly more testosterone pulses of shorter interpulse duration than OSA subjects and middle‐aged controls. After adjusting for age and BMI, the three groups differed in mean and AUC values of LH and testosterone. Analysis of covariance, using BMI as a covariate, revealed a statistically significant group effect on mean and AUC testosterone values (p = 0.03; p < 0.003, respectively). Eliminating young controls, there was a significant positive correlation between the amount of LH and testosterone secreted at night. After partialling out age alone and BMI alone, the mean LH and mean testosterone were still positively correlated.Discussion: Thus, OSA is associated with decreased pituitary‐gonadal function. The decline in testosterone concentrations is due to obesity and advanced age and to a lesser degree to sleep fragmentation and hypoxia.
Overweight and Obesity: Knowledge, Attitudes, and Practices of General Practitioners in France
Authors: Bocquier Aurélie , Verger Pierre , Basdevant Arnaud , Andreotti Gérard , Baretge Jean , Villani Patrick , Paraponaris Alain 
Published: April 2008

AbstractObjective: To describe the current knowledge, attitudes, and practices of French general practitioners (GPs) in the field of adult overweight and obesity management.Research Methods and Procedures: A cross‐sectional telephone survey interviewed a sample of 600 GPs, representative of the private GPs in southeastern France. A four‐part questionnaire assessed personal and professional characteristics, attitudes and opinions about overweight and obesity, relevant knowledge and training, and practices (diagnostic methods, clinical assessments, weight loss objectives, types of counseling).Results: Most GPs knew that weight problems are health‐threatening, and 79% agreed that managing these problems is part of their role. Nevertheless, 58% did not feel they perform this role effectively, and one‐third did not find it professionally gratifying. Approximately 30% had negative attitudes toward overweight and obese patients; 57% were pessimistic about patients’ ability to lose weight; 64% often set weight loss objectives more demanding than guidelines call for; and neither food diaries nor nutritional education were used systematically. GPs’ feelings of effectiveness and attitudes toward obese patients were associated with some professional (training) and personal (BMI, personal diet experience) characteristics.Discussion: GPs’ feelings of ineffectiveness may stem from an underlying conflict between practitioners’ and patients’ representations of weight problems and the relationship problems this causes. Inadequate practices and health care system organization may also play a role.