bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasma Leptin and Blood Pressure in Men: Graded Association Independent of Body Mass and Fat Pattern
Authors: Barba Gianvincenzo , Russo Ornella , Siani Alfonso , Iacone Roberto , Farinaro Eduardo , Gerardi Maria Clara , Russo Paola , Della Valle Elisabetta , Strazzullo Pasquale
Published: April 2008

Objective: The role of leptin in the association between body mass, central adiposity, and blood pressure (BP) is controversial. This study evaluated the relationship between leptin and BP in relation to body mass index (BMI) and fat distribution in a large sample of untreated male adults.

Research Methods and Procedures: The study population was made up of 457 untreated male employees of the Olivetti factory in Naples. Plasma leptin, complete anthropometry, BP, and relevant biochemical variables were measured.

Results: Log‐transformed plasma leptin levels were directly associated with BMI (r = 0.661, p < 0.001) and waist circumference (r = 0.630; p < 0.001). Leptin also correlated with systolic (r = 0.258) and diastolic (r = 0.277) BP (p < 0.001). The association between leptin and BP was maintained after accounting for age, BMI (or waist circumference), log‐insulin, and serum creatinine (p < 0.01); this association was stronger than that with BMI. Logistic regression analysis showed that an increased prevalence of hypertension (BP ≥ 140 and/or 90 mm Hg) was associated with high plasma leptin levels when controlling for age and waist circumference (odds ratio, 1.99; 95%CI, 1.06 to 3.72) or for age and BMI (odds ratio, 1.92; 95%CI, 1.02 to 3.61).

Discussion: A graded positive relationship between plasma leptin levels and BP was observed in this sample of untreated male adults. This association was independent of age, BMI, abdominal adiposity, and fasting plasma insulin. Moreover, elevated plasma leptin concentrations were associated with greater probability of hypertension, again independently of potential confounders.
Reduced PDK4 Expression Associates with Increased Insulin Sensitivity in Postobese Patients
Authors: Rosa Giuseppina , Di Rocco Paola , Manco Melania , Greco Aldo V. , Castagneto Marco , Vidal Hubert , Mingrone Geltrude
Published: April 2008

Objective: The aim of this study was to verify whether changes in PDK4 mRNA expression in skeletal muscle in formerly obese subjects who underwent malabsorptive bariatric surgery [bilio‐pancreatic diversion (BPD)] might be related to insulin sensitivity improvement, and if these possible modifications might correlate with a reduction of the intramyocytic lipid level.

Research Methods and Procedures: Six obese women (body mass index 46.6 ± 8.2 kg/m2) were enrolled in the study. Body composition, euglycemic‐hyperinsulinemic clamp and muscle biopsies for skeletal muscle lipid analysis, and semiquantitative reverse transcriptase‐polymerase chain reaction were performed before and 3 years after BPD.

Results: The average weight loss observed after surgery was ∼42%. Increased glucose uptake was accompanied by a significant decrease of PDK4 mRNA (R2 = 0.71, p < 0.001). The amounts of intramyocytic triglycerides correlate directly with PDK4 mRNA (R2 = 0.87, p = 0.005) and inversely with glucose uptake values (R2 = 0.75, p < 0.001).

Discussion: Our results support the concept that a reduced tissue availability of fatty acids consequent to a massive lipid malabsorption influences glucose metabolism acting through the regulation of PDH complex. In fact, as shown in animals, a higher level of FFA availability is likely to induce overexpression of PDK4 also in humans.
Emotional Eating, Alexithymia, and Binge‐Eating Disorder in Obese Women
Authors: Pinaquy Sandrine , Chabrol Henri , Simon Chantal , Louvet Jean‐Pierre , Barbe Pierre
Published: April 2008

Objective: To investigate the relationships between alexithymia and emotional eating in obese women with or without Binge Eating Disorder (BED).

Research Methods and Procedures: One hundred sixty‐nine obese women completed self‐report questionnaires, including the Beck Depression Inventory, the State Trait Anxiety Inventory, the Stress Perceived Scale, the Dutch Eating Behaviour Questionnaire, and the Toronto Alexithymia Scale. The presence of BED, screened using the Questionnaire of Eating and Weight Patterns, was confirmed by interview.

Results: Forty obese women were identified as having BED. BED subjects and non‐BED subjects were comparable in age, body mass index, educational level, and socioeconomic class. According to the Dutch Eating Behaviour Questionnaire, BED subjects exhibited higher depression, anxiety, perceived stress, alexithymia scores, and emotional and external eating scores than non‐BED subjects. Emotional eating and perceived stress emerged as significant predictors of BED. The relationships between alexithymia and emotional eating in obese subjects differed between the two groups according to the presence of BED. Alexithymia was the predictor of emotional eating in BED subjects, whereas perceived stress and depression were the predictors in non‐BED subjects.

Discussion: This study pointed out different relationships among mood, alexithymia, and emotional eating in obese subjects with or without BED. Alexithymia was linked to emotional eating in BED. These data suggest the involvement of alexithymia in eating disorders among obese women.
Birth Weight, Adult Body Composition, and Subcutaneous Fat Distribution
Authors: te Velde Saskia J. , Twisk Jos W.R. , van Mechelen Willem , Kemper Han C.G.
Published: April 2008

Objectives: To investigate if birth weight is related to both body mass index (BMI) and distribution of subcutaneous fat at adult age.

Research Methods and Procedures: A 9‐year longitudinal study was performed in 229 subjects (192 women) with ages ranging from 27 to 36 years. Birth weight was retrieved by a questionnaire, and adult weight, height, skinfold thicknesses, and waist‐to‐hip ratio (WHR) were repeatedly measured at mean ages 27, 29, 31, and 36 years. BMI, sum of four skinfolds (S4S), the ratio between two truncal skinfolds and S4S (SS/S4S), and the ratio between WHR and the cross‐sectional area of the left thigh were calculated with the available data.

Results: The adjusted model showed that in women, birth weight was significantly negatively related to adult S4S [β = −5.211; (−9.768 to −0.654)], waist circumference [β = −1.449; (−2.829 to −0.069)], and SS/S4S ratio [β = −3.579; (−5.296 to −1.862)]. In men, a significant negative association was observed between birth weight and adult WHR [β = −1.096; (−2.092 to −0.100)] only. Other relationships showed, although not significantly, the same negative trend, namely that lower birth weight is related to higher adult body fat mass (S4S) and a more truncal subcutaneous fat distribution (SS/S4S). No associations were found between birth weight and either adult BMI or the cross‐sectional area of the thigh.

Discussion: Lower birth weight is, in both adult men and women, related to a higher adult subcutaneous fat mass and a more truncal distribution of subcutaneous fat, indicating a higher risk for obesity.
Relationship of Neck Circumference to Cardiovascular Risk Factors
Authors: Ben‐Noun Liubov (Louba) , Laor Arie
Published: April 2008

Objective: To determine a relationship between neck circumference (NC) and risk factors for coronary heart disease by evaluating the components of the metabolic syndrome.

Research Methods and Procedures: The study group included 561 subjects (231 men and 330 women) who had no known major medical conditions and were not receiving any medication therapy. The subjects were those who attended a family health clinic for any reason between 1998 and December 2001. Main indicators studied included NC, waist circumference, waist‐to‐hip ratio, body mass index, blood pressure, and lipoprotein, glucose, and uric acid levels.

Results: Pearson's correlation coefficients indicated a significant association between NC and body mass index (men, r = 0.71; women, r = 0.81; each, p < 0.0001), waist circumference (men, r = 0.75; women, r = 0.79; each, p < 0.0001), waist‐to‐hip ratio (men, r = 0.56; women, r = 0.63; each, p < 0.0001), total cholesterol (men, r = 0.50; women, r = 0.66; each, p < 0.0001), low‐density lipoprotein‐cholesterol (men, r = 0.42; women, r = 0.60; each, p < 0.0001), triglycerides (men, r = 0.48; women, r = 0.49; each, p < 0.0001), glucose (men, r = 0.21, p < 0.001; women, r = 0.44; p < 0.0001), uric acid (men, r = 0.50, p < 0.0001; women, r = 0.60, p < 0.001), and systolic (men, r = 0.53; women, r = 0.69; each, p < 0.0001), and diastolic (men, r = 0.55; women, r = 0.65; each, p < 0.0001) blood pressure.

Discussion: Higher NC is correlated positively with the factors of the metabolic syndrome; therefore, it is likely to increase the risk of coronary heart disease.
Weight Goals in a College‐age Population
Authors: Anderson Drew A. , Lundgren Jennifer D. , Shapiro Jennifer R. , Paulosky Caroline A.
Published: April 2008

Objective: Although a growing body of literature has found unrealistic weight loss goals to be common among older, primarily female, subjects, little is known about weight loss goals of younger adults.

Research Methods and Procedures: Three hundred seventy‐nine college students had their height and weight taken and reported their “goal,” “dream,” “happy,” “acceptable,” and “disappointed” weights. A series of 2 (gender) × 2 (nonoverweight vs. overweight) ANOVAs were conducted with both absolute weight goals and percentage of weight loss needed to obtain those goals as dependent variables.

Results: When examined in terms of absolute weight goals, women generally had lower body mass index (BMI) goals than men, and nonoverweight participants had lower BMI goals than overweight participants. Surprisingly, most overweight participants would accept a weight loss that would still place them in the overweight BMI range. When examined in terms of percentage loss needed to reach those goals, only overweight women chose goal and dream weights that would require a loss greater than can be expected from nonsurgical weight‐loss treatments, and all overweight participants chose happy and acceptable weights within 15% of current weight.

Discussion: Participants in this study had generally reasonable weight‐loss goals, and even the most extreme weight loss goals were much more moderate than those found in previous studies. These results are surprising given the extreme social pressures for thinness facing young adults. Future studies should examine the variables that influence selection of goal weights and how goal weights affect actual dieting behavior.
DRF 2655: A Unique Molecule that Reduces Body Weight and Ameliorates Metabolic Abnormalities
Authors: Vikramadithyan Reeba K. , Hiriyan Jagadheshan , Suresh Juluri , Gershome Cynthia , Babu Ravi K. , Misra Parimal , Rajagopalan Ramanujam , Chakrabarti Ranjan
Published: April 2008

Objective: Preclinical evaluation of DRF 2655, a peroxisome proliferator‐activated receptor alpha (PPARα) and PPARγ agonist, as a body‐weight lowering, hypolipidemic and euglycemic agent.

Research Methods and Procedures: DRF 2655 was studied in different genetic, normal, and hyperlipidemic animal models. HEK 293 cells were used to conduct the reporter‐based transactivation of PPARα and PPARγ. To understand the biochemical mechanism of lipid‐, body‐weight‐, and glucose‐lowering effects, activities of key β‐oxidation and lipid catabolism enzymes and gluconeogenic enzymes were studied in db/db mice treated with DRF 2655. 3T3L1 cells were used for adipogenesis study, and HepG2 cells were used to study the effect of DRF 2655 on total cholesterol and triglyceride synthesis using [14C]acetate and [3H]glycerol.

Results: DRF 2655 showed concentration‐dependent transactivation of PPARα and PPARγ. In the 3T3L1 cell‐differentiation study, DRF 2655 and rosiglitazone showed 369% and 471% increases, respectively, in triglyceride accumulation. DRF 2655 showed body‐weight lowering and euglycemic and hypolipidemic effects in various animal models. db/db mice treated with DRF 2655 showed 5‐ and 3.6‐fold inhibition in phosphoenolpyruvate carboxykinase and glucose 6‐phosphatase activity and 651% and 77% increases in the β‐oxidation enzymes carnitine palmitoyltransferase and carnitine acetyltransferase, respectively. HepG2 cells treated with DRF 2655 showed significant reduction in lipid synthesis.

Discussion: DRF 2655 showed excellent euglycemic and hypolipidemic activities in different animal models. An exciting finding is its body‐weight lowering effect in these models, which might be mediated by the induction of target enzymes involved in hepatic lipid catabolism through PPARα activation.
Absence of Hypersensitivity to Glucocorticoids in Antiretroviral‐associated Lipodystrophy
Authors: Martin Ian P. , Breen Patricia A. , Weigle David S.
Published: April 2008

Objective: The lipodystrophy syndrome, which is associated with the use of antiretroviral drugs in some human immunodeficiency virus (HIV)‐infected individuals, bears a striking similarity to the fat redistribution observed in Cushing's disease. Although urinary free cortisol excretion and glucocorticoid receptor binding affinity are not elevated in subjects with lipodystrophy, glucocorticoid action at the cellular level has not been examined in affected individuals. The objective of this study was to determine whether tissue sensitivity to glucocorticoids is increased in subjects with lipodystrophy taking protease inhibitors.

Research Methods and Procedures: Subjects included 11 HIV‐infected men on protease inhibitor therapy with lipodystrophy and 10 control HIV‐infected men not on protease inhibitor therapy and without lipodystrophy. Trunk to extremity fat ratio was measured by DXA. Dexamethasone suppression of peripheral blood mononuclear cell proliferation was measured as an index of tissue sensitivity to glucocorticoid action.

Results: Compared with the control group, subjects with lipodystrophy had a significant elevation of the trunk to extremity fat ratio [median (interquartile range): 2.9 (1.3) vs. 1.6 (1.2); p < 0.05]. The concentration of dexamethasone resulting in 50% maximal suppression of proliferation was 11.7 nM (9.3 nM) in subjects with lipodystrophy and 19.6 nM (9.7 nM) in control subjects (p = not significant), and the percentage minimal proliferation was 4% (12%) and 17% (18%) in the two groups, respectively (p = not significant).

Discussion: Despite the Cushingoid appearance of affected individuals, these data suggest that body fat redistribution in antiretroviral‐associated lipodystrophy does not arise through an increase in postreceptor glucocorticoid signaling.
Regulation of Resistin by Gonadal, Thyroid Hormone, and Nutritional Status
Authors: Nogueiras Rubén , Gualillo Oreste , Caminos J. Eduardo , Casanueva Felipe F. , Diéguez Carlos
Published: April 2008

Objective: Resistin was recently identified as a hormone secreted by adipocytes that is under hormonal and nutritional control. This hormone has been suggested to be the link between obesity and type 2 diabetes. The aim of this study was to assess the influence of gender, gonadal status, thyroid hormones, pregnancy, and food restriction on resistin mRNA levels in adipose tissue of rats.

Research Methods and Procedures: We have determined resistin mRNA expression by Northern blot analysis in all experimental sets.

Results: Resistin mRNA expression is influenced by age, with the highest hormone levels existing at 45 days after birth and decreasing thereafter. Resistin mRNA expression is higher in men than in women. Moreover, we studied the effect of orchidectomy and ovariectomy in rats of different ages and showed that gonadal hormones increase adipose tissue resistin mRNA expression in male rats. Resistin is also regulated by thyroid hormones; it is severely decreased in hyperthyroid rats. Our results clearly show that chronic food restriction (30% of ad libitum food intake) led to a decrease in adipose tissue mRNA levels in normal cycling female rats and pregnant rats. In pregnancy, resistin mRNA levels were enhanced particularly at midgestation.

Discussion: Our observations indicate that resistin is influenced by gender, gonadal status, thyroid hormones, and pregnancy. These findings suggest that resistin could explain the decreased insulin sensitivity during puberty and could be the link between sex steroids and insulin sensitivity. Moreover, resistin could mediate the effect of thyroid hormones on insulin resistance and the state of insulin resistance present during pregnancy.
Associations of Aging and Birth Cohort with Body Mass Index in a Biethnic Cohort
Authors: Juhaeri  , Stevens June , Jones Daniel W. , Arnett Donna
Published: April 2008

Objective: To examine associations of aging and birth cohort with body mass index (BMI) in a biethnic cohort.

Research Methods and Procedures: This was a longitudinal closed cohort study of 14, 500 white and African‐American men and women, 45 to 64 years of age, followed for 9 years. Aging was defined as the length of the interval in years between baseline and following visits. Birth cohort was defined by the year in which participants were born. Mixed model analyses were used to examine associations of aging, birth cohort, and BMI in four ethnicity‐gender groups.

Results: We found that aging was associated with an increase in BMI in white and African‐American men and women. The associations between aging and BMI were stronger in the younger birth cohorts. Except for white women, younger birth cohort was associated with a higher BMI. After adjusting for aging, birth cohort was associated with an increase in BMI of 0.1 kg/m2 [95% confidence interval (95% CI): −0.1, 0.3] among white women. The corresponding values for African‐American women, white men, and African‐American men are 0.5 kg/m2 (95% CI: 0.1, 0.9), 0.6 kg/m2 (95% CI: 0.4, 0.8), and 0.6 kg/m2 (95% CI: 0.2, 1.0), respectively.

Discussion: Our analyses show that, in all except white women, people in this age range who were born later have a higher BMI at the same attained age. In all groups, people who are born later gained more weight as they aged. In general, subjects ages 45 to 64 years gained weight as they aged 9 years.
The Relationship of Rapid Weight Gain in Infancy to Obesity and Skeletal Maturity in Childhood
Authors: Cameron Noël , Pettifor John , De Wet Thea , Norris Shane
Published: April 2008

Objective: Children with birth weight appropriate for gestational age (AGA) who also demonstrate rapid weight gain in infancy have a greater risk of being overweight or obese during childhood. A concurrent advancement in skeletal maturity would account for their greater size and would, therefore, not necessarily pose a threat of greater risk during adolescence and early adulthood. This study aims to determine whether children with rapid weight gain during infancy have advanced skeletal maturity during childhood.

Research Methods and Procedures: One hundred and ninety‐three African children (boys = 108; girls = 85) of normal birth weight and gestational age were assessed from birth to 9 years. Body composition was assessed at 9 years of age by whole‐body DXA, and skeletal maturity was assessed using the Tanner‐Whitehouse II technique. Rapid weight gain in infancy was defined as a +0.67 change in weight‐for‐age Z‐score between birth and 2 years.

Results: Rapid weight gain was experienced by over 20% of the sample. Children with rapid weight gain were significantly lighter at birth and significantly taller, heavier, and fatter throughout childhood. Chronological age and Tanner‐Whitehouse II technique skeletal ages at 9 years were not significantly different between groups or between sexes within groups.

Discussion: Because AGA children with rapid weight gain have a greater risk of overweight and obesity but are not advanced in skeletal maturity, later adolescent adjustments toward average weight and fatness values are unlikely. The identification and monitoring of such children is of importance in reducing their risk of morbidity.
Plasma Markers of Cholesterol Homeostasis and Apolipoprotein B‐100 Kinetics in the Metabolic Syndrome
Authors: Chan Dick C. , Watts Gerald F. , Barrett P. Hugh R. , O'Neill Frans H. , Thompson Gilbert R.
Published: April 2008

Objective: The metabolic syndrome is characterized by defective hepatic apolipoprotein B‐100 (apoB) metabolism. Hepato‐intestinal cholesterol metabolism may contribute to this abnormality.

Research Methods and Procedures: We examined the association of cholesterol absorption and synthesis with the kinetics of apoB in 35 obese subjects with the metabolic syndrome. Plasma ratios of campesterol and lathosterol to cholesterol were used to estimate cholesterol absorption and synthesis, respectively. Very‐low‐density lipoprotein (VLDL), intermediate‐density lipoprotein (IDL), and low‐density lipoprotein apoB kinetics were studied using stable isotopy and mass spectrometry. Kinetic parameters were derived using multicompartmental modeling.

Results: Compared with controls, the obese subjects had significantly lower plasma ratios of campesterol, but higher plasma ratios of lathosterol (p < 0.05 in both). This was associated with elevated VLDL‐apoB secretion rate (p < 0.05) and delayed fractional catabolism of IDL and low‐density lipoprotein‐apoB (p < 0.01). In the obese group, plasma ratios of campesterol correlated inversely with VLDL‐apoB secretion (r = −0.359, p < 0.05), VLDL‐apoB (r = −0.513, p < 0.01) and IDL‐apoB (r = −0.511, p < 0.01) pool size, and plasma lathosterol ratio (r = −0.366, p < 0.05). Subjects with low cholesterol absorption had significantly higher VLDL‐apoB secretion, VLDL‐apoB and IDL‐apoB pool size, and plasma lathosterol ratio (p < 0.05 in both) than those with high cholesterol absorption.

Discussion: Subjects with the metabolic syndrome have oversecretion of VLDL‐apoB and decreased catabolism of apoB‐containing particles and low absorption and high synthesis rates of cholesterol. These changes in cholesterol homeostasis may contribute to the kinetic defects in apoB metabolism in the metabolic syndrome.
K121Q PC‐1 Gene Polymorphism Is Not Associated with Insulin Resistance in a Spanish Population
Authors: González‐Sánchez José Luis , Martínez‐Larrad María Teresa , Fernández‐Pérez Cristina , Kubaszek Agata , Laakso Markku , Serrano‐Ríos Manuel
Published: April 2008

Objective: To investigate the effect of the K121Q plasma cell membrane glycoprotein (PC‐1) polymorphism on the components of the insulin resistance syndrome in a population‐based nationwide multicenter study in Spain.

Research Methods and Procedures: The subjects of the study were 293 nonrelated adults (44.7% men and 55.3% women) ages 35 to 64 years randomly chosen from a nationwide population‐based survey on obesity and related conditions, including insulin resistance and cardiovascular risk factors. Obesity‐related anthropometric measurements included blood pressure, oral glucose tolerance test, lipid profile (total cholesterol, high‐density lipoprotein‐ and low‐density lipoprotein‐cholesterol, and triglycerides), plasma leptin, insulin levels by radioimmunoassay, and insulin resistance (homeostasis model assessment). K121Q PC‐1 genotypes were determined by restriction fragment‐length polymorphism‐polymerase chain reaction.

Results: Overall Q allele frequency was 0.14, with no differences between obese and nonobese individuals (0.15 vs. 0.13). After adjustment for sex, age, BMI, and degree of glucose tolerance, the Q allele was associated with high plasma leptin and triglyceride levels, but not with insulin resistance.

Discussion: The results showed that the K121Q PC‐1 polymorphism in the Spanish population has no significant impact on insulin sensitivity.
Decreased Uncoupling Protein Expression and Intramyocytic Triglyceride Depletion in Formerly Obese Subjects
Authors: Mingrone Geltrude , Rosa Giuseppina , Greco Aldo V. , Manco Melania , Vega Nathalie , Hesselink Matthijs K. , Castagneto Marco , Schrauwen Patrick , Vidal Hubert
Published: April 2008

Objective: To examine the muscular uncoupling protein expression 2 (UCP2) and UCP3 gene expression in morbid obese subjects before and after bariatric surgery [bilio‐pancreatic diversion (BPD)].

Research Methods and Procedures: Eleven obese subjects (BMI = 49 ± 2 kg/m2) were studied before BPD and 24 months after BPD. Skeletal muscle UCP2 and UCP3 mRNA was measured using reverse transcriptase‐competitive polymerase chain reaction and UCP3 protein by Western blotting. Intramyocytic triglycerides were quantified by high‐performance liquid chromatography. Twenty‐four‐hour energy expenditure and respiratory quotient (RQ) were measured in a respiratory chamber.

Results: After BPD, the average weight loss was ∼38%. Nonprotein RQ was increased in the postobese subjects (0.73 ± 0.00 vs. 0.83 ± 0.02, p < 0.001). The intramyocytic triglyceride level dropped (3.66 ± 0.16 to 1.60 ± 0.29 mg/100 mg of fresh tissue, p < 0.0001) after BPD. Expression of UCP2 and UCP3 mRNA was significantly reduced (from 35.9 ± 6.1% to 18.6 ± 4.5% of cyclophilin, p = 0.02; from 60.2 ± 14.0% to 33.4 ± 8.5%, p = 0.03; respectively). UCP3 protein content was also significantly reduced (272.19 ± 84.13 vs. 175.78 ± 60.31, AU, p = 0.04). A multiple regression analysis (R2 = 0.90) showed that IMTG levels (p = 0.007) represented the most powerful independent variable for predicting UCP3 variation.

Discussion: The strong correlation of UCP expression and decrease in IMTG levels suggests that triglyceride content plays an even more important role in the regulation of UCP gene expression than the circulating levels of free fatty acids or the achieved degree of weight loss.
Geographic and Demographic Variation in the Prevalence of Overweight Canadian Children
Authors: Willms J. Douglas , Tremblay Mark S. , Katzmarzyk Peter T.
Published: April 2008

Objective: To examine the geographic and demographic variation in the prevalence of overweight Canadian children.

Research Methods and Procedures: Using BMI data from the 1981 Canada Fitness Survey and the 1996 National Longitudinal Survey of Children and Youth, this study assessed: 1) the prevalence of overweight and obesity among Canadian boys and girls ages 7 to 13 years; 2) secular trends in the prevalence of overweight from 1981 to 1996, by province and adjusted for age and sex; and 3) provincial variation in the prevalence of overweight, before and after adjusting for socioeconomic and demographic characteristics.

Results: The prevalence of boys and girls classified as overweight in 1996 was 33% and 26%, respectively. The corresponding figures for obesity were 10% for boys and 9% for girls. Provincial variation was observed with a trend of increasing risk of being overweight from west to east. Socioeconomic status was inversely related to the prevalence of overweight regardless of geographic region. The risk of being overweight was more related to geography (province) than demographic variables (income and family background); however, the effect of secular trends (1981 to 1996) exceeded the effect of geographic or demographic variables.

Discussion: The prevalence of childhood overweight and obesity is increasing in all areas of Canada and can be explained only partially by geographic or demographic characteristics.
Novel recombinant thrombolytic and antithrombotic staphylokinase variants with an RGD motif at their N‐termini
Authors: He Jintian , Di Jingfang , Xu Ruiguang , Zhao Baohua
Published: April 2008

To develop a more potent thrombolytic agent, four Sak (staphylokinase) variants were constructed, in which RGD (Arg‐Gly‐Asp) sequences are introduced into diferent sites of the N‐terminus of Sak. These variants were successfully expressed in Escherichia coli DH5α as soluble cytoplasmic proteins in a 5‐litre fermentor and accounted for more than 40% of the total cellular protein. The expressed proteins were subsequently purified, employing a similar three‐step chromatographic purification process. SDS/PAGE and HPLC–MS analyses indicated that the purified proteins were almost completely homogeneous, the purity of the variants exceeding 95%. Further investigations into the properties of the Sak variants showed that mutations at the N‐terminus significantly affected N‐terminal methionine excision, and serine residues at the N‐terminus of Sak appeared to play an important role in the process. Kinetic analysis of r‐Sak (recombinant Sak) and its variants using plasminogen as substrate indicated that the mutations affected the proteolysis. In addition, a significant inhibitory effect of the Sak variants at 2.0 μM was observed on the ADP‐induced aggregation of platelets compared with that of r‐Sak, whether N‐terminally cleaved or not (P<0.05). Furthermore, the inhibitory activity of Sak variants after N‐terminal proteolysis was higher than that of native Sak variants.
Metalloprotease‐mediated OPA1 processing is modulated by the mitochondrial membrane potential
Authors: Guillery Olwenn , Malka Florence , Landes Thomas , Guillou Emmanuelle , Blackstone Craig , Lombès Anne , Belenguer Pascale , Arnoult Damien , Rojo Manuel
Published: April 2008

Background information. Human OPA1 (optic atrophy type 1) is a dynamin‐related protein of the mitochondrial IMS (intermembrane space) involved in membrane fusion and remodelling. Similarly to its yeast orthologue Mgm1p that exists in two isoforms generated by the serine protease Pcp1p/Rbd1p, OPA1 exists in various isoforms generated by alternative splicing and processing. In the present paper, we focus on protease processing of OPA1.

Results. We find that various mammalian cell types display a similar pattern of OPA1 isoforms [two L‐OPA1 (long isoforms of OPA1) and three S‐OPA1 (short isoforms of OPA1)] and that loss of the inner membrane potential, but not inhibition of oxidative phosphorylation or glycolysis, induces rapid and complete processing of L‐OPA1 to S‐OPA1. In isolated mitochondria, OPA1 processing was inhibited by heavy‐metal chelators, pointing to processing by a mitochondrial metalloprotease. The pattern of OPA1 isoforms and its processing kinetics were normal in mitochondria devoid of the serine protease PARL (presenilins‐associated rhomboid‐like protein) – the human orthologue of Pcp1/Rbd1 – and in cells from patients carrying homozygous mutations in SPG7 (spastic paraplegia type 7), a gene encoding the matrix‐oriented metalloprotease paraplegin. In contrast, OPA1 processing kinetics were delayed upon knock‐down of YME1L (human yme1‐like protein), an IMS‐oriented metalloprotease. OPA1 processing was also stimulated during apoptosis, but inhibition of this processing did not affect apoptotic release of OPA1 and cytochrome c. Finally, we show that all OPA1 isoforms interact with Mfn1 (mitofusin 1) and Mfn2 and that these interactions are not affected by dissipation of ΔΨm (inner mitochondrial membrane potential) or OPA1 processing.

Conclusions. Metalloprotease‐mediated processing of OPA1 is modulated by the inner membrane potential and is likely to be mediated by the YME1L protease.
In nucleoli, the steady state of nucleolar proteins is leptomycin B‐sensitive
Authors: Muro Eleonora , Hoang Thang Q. , Jobart‐Malfait Aude , Hernandez‐Verdun Danièle
Published: April 2008

Background information. The nucleolus is a dynamic structure. It has been demonstrated that nucleolar proteins rapidly associate with and dissociate from nucleolar components in continuous exchanges with the nucleoplasm using GFP (green fluorescent protein)‐tagged proteins. However, how the exchanges within one nucleolus and between nucleoli within the nuclear volume occurred is still poorly understood.

Results. The movement of PAGFP (photoactivatable GFP)‐tagged proteins that become visible after photoactivation can be followed. In the present study, we establish the protocol allowing quantification of the traffic of PAGFP‐tagged nucleolar proteins in nuclei containing two nucleoli. The traffic in the activated area, at the periphery of the activated area and to the neighbouring nucleolus is measured. Protein B23 is rapidly replaced in the activated area, and at the periphery of the activated area the steady state suggests intranucleolar recycling of B23; this recycling is LMB (leptomycin B)‐sensitive. The pool of activated B23 is equally distributed in the volume of the two nucleoli within 2 min. The three‐dimensional distribution of the proteins Nop52 and fibrillarin is less rapid than that of B23 but is also LMB‐sensitive. In contrast, traffic of fibrillarin from the nucleoli to the CB (Cajal body) was not modified by LMB.

Conclusions. We propose that the steady state of nucleolar proteins in nucleoli depends on the affinity of the proteins for their partners and on intranucleolar recycling. This steady state can be impaired by LMB but not the uptake in the neighbouring nucleolus or the CB.
Similarity and diversity in mechanisms of muscle fate induction between ascidian species
Authors: Hudson Clare , Yasuo Hitoyoshi
Published: April 2008

Developmental processes can change during evolution at many levels of the ontogeny of an individual. Embryos of solitary ascidians have a largely invariant mode of development, with fixed cleavage patterns and fate maps. Thus the cell lineages and final body plan of the two quite distantly related species considered in this review, Ciona intestinalis and Halocynthia roretzi, are highly similar. However, close comparison of the developmental mechanisms used by these two species provide examples of evolutionary changes and help pinpoint which aspects of development are evolutionarily flexible. Examples of both similarity and diversity are observed in the mechanisms used to generate the full complement of larval muscle. We will describe the changes in muscle‐cell lineage, as well as some striking differences in the intercellular signalling pathways used to induce muscle fate. The somewhat surprising conclusion is that in ascidians, as in nematode vulval development, different signalling mechanisms have been adopted to mediate similar interactions between equivalently positioned cells.
Spin-orbit configuration interaction study of the electronic structure of the 5f2 manifold of U4+ and the 5f manifold of U5+
Authors: Danilo Cécile , Vallet Valérie , Flament Jean-Pierre , Wahlgren Ulf
Published: April 2008

The energy levels of the 5f configuration of U5+ and 5f2 configuration of U4+ have been calculated in a dressed effective Hamiltonian relativistic spin-orbit configuration interaction framework. Electron correlation is treated in the scalar relativistic scheme with either the multistate multireference second-order multiconfigurational perturbation theory (MS-CASPT2) or with the multireference single and double configuration interaction (MRCI) and its size-extensive Davidson corrected variant. The CASPT2 method yields relative energies which are lower than those obtained with the MRCI method, the differences being the largest for the highest state S01 of the 5f2 manifold. Both valence correlation effects and spin-orbit polarization of the outer-core orbitals are shown to be important. The satisfactory agreement of the results with experiments and four-component correlated calculations illustrates the relevance of dressed spin-orbit configuration interaction methods for spectroscopy studies of heavy elements.
Hypersonic velocity impact on a-SiC target: A diagram of damage characteristics via molecular dynamics simulations
Authors: Makeev Maxim A. , Srivastava Deepak
Published: April 2008

Dynamic damage response characteristics of an amorphous silicon carbide target due to hypersonic velocity impacts of diamond projectiles are investigated using molecular dynamics simulations. In a certain range of radii of the projectile, four distinct regimes of damage are uncovered and summarized in a penetration depth diagram. The regimes correspond to shallow crater formation, deep penetration into the target, deep penetration with local melting of the target, and complete disintegration of the projectile. In the third regime, a logarithmic dependence of the penetration depth as a function of the projectile velocity has been found and explained by an analytical model.
Unbiased τ-leap methods for stochastic simulation of chemically reacting systems
Authors: Xu Zhouyi , Cai Xiaodong
Published: April 2008

The τ-leap method first developed by Gillespie [D. T. Gillespie, J. Chem. Phys. 115, 1716 (2001)] can significantly speed up stochastic simulation of certain chemically reacting systems with acceptable losses in accuracy. Recently, several improved τ-leap methods, including the binomial, multinomial, and modified τ-leap methods, have been developed. However, in all these τ-leap methods, the mean of the number of times, Km, that the mth reaction channel fires during a leap is not equal to the true mean. Therefore, all existing τ-leap methods produce biased simulation results, which limit the simulation accuracy and speed. In this paper, we analyze the mean of Km based on the chemical master equation. Using this analytical result, we develop unbiased Poisson and binomial τ-leap methods. Moreover, we analyze the variance of Km, and then develop an unbiased Poisson/Gaussian/binomial τ-leap method to correct the errors in both the mean and variance of Km. Simulation results demonstrate that our unbiased τ-leap method can significantly improve simulation accuracy without sacrificing speed.
Propagation of complex shaped ultrafast pulses in highly optically dense samples
Authors: Davis J. C. , Fetterman M. R. , Warren W. S. , Goswami D.
Published: April 2008

We examine the propagation of shaped (amplitude- and frequency-modulated) ultrafast laser pulses through optically dense rubidium vapor. Pulse reshaping, stimulated emission dynamics, and residual electronic excitation all strongly depend on the laser pulse shape. For example, frequency swept pulses, which produce adiabatic passage in the optically thin limit (independent of the sign of the frequency sweep), behave unexpectedly in optically dense samples. Paraxial Maxwell optical Bloch equations can model our ultrafast pulse propagation results well and provide insight.
Gating of single molecule transistors: Combining field-effect and chemical control
Authors: Perrine Trilisa M. , Smith Ron G. , Marsh Christopher , Dunietz Barry D.
Published: April 2008

Previously we have demonstrated that several structural features are crucial for the functionality of molecular field-effect transistors. The effect of additional structural aspects of molecular wires is explored. These include the type of, the thiol binding location on, and the chemical substitutions of a conjugated system. Pentacene, porphyrin, and the Tour–Reed devices are utilized as model systems. The thiol binding location is shown to have a varied effect on the transmission of a system depending on the molecular orbitals involved. Substitution by electron withdrawing and donating groups is illustrated to have a substantial effect on the transmission of single molecule devices. The substitution effect is either a simple energy shifting effect or a more complicated resonance effect, and can be used to effectively tune the electronic behavior of a single molecule field effect transistor.
Analysis and refinement of the Cu(001)c(2×2)CO–He potential using He3 selective adsorption resonances
Authors: Riley D. J. , Jardine A. P. , Alexandrowicz G. , Hedgeland H. , Ellis J. , Allison W.
Published: April 2008

Measurements of He3 scattering from the Cu(001)c(2×2)CO surface using He3 spin-echo spectroscopy show a number of selective adsorption resonance features. The features cannot be reproduced by close coupled scattering calculations based on the existing Cu(001)c(2×2)CO–He interaction potential. An empirical potential is created by adjusting the shape, depth, and width of the existing potential to improve agreement with the experimental data.
Polymer translocation through a cylindrical channel
Authors: Wong Chiu Tai Andrew , Muthukumar M.
Published: April 2008

A formalism of polymer translocation through a cylindrical channel of finite diameter and length between two spherical compartments is developed. Unlike previous simplified systems, the finite diameter of the channel allows the number of polymer segments inside the channel to be adjusted during translocation according to the free energy of possible conformations. The translocation process of a Gaussian chain without excluded volume and hydrodynamic interactions is studied using exact formulas of confinement free energy under this formalism. The free energy landscape for the translocation process, the distribution of the translocation time, and the average translocation time are presented. The complex dependencies of the average translocation time on the length and diameter of the channel, the sizes of the donor and receptor compartments, and the chain length are illustrated.
Thermotropic biaxial nematic liquid crystals: Spontaneous or field stabilized?
Authors: Vanakaras Alexandros G. , Photinos Demetri J.
Published: April 2008

An intermediate nematic phase is proposed for the interpretation of recent experimental results on phase biaxiality in bent-core nematic liquid crystals. The phase is macroscopically uniaxial but has microscopic biaxial, and possibly polar, domains. Under the action of an electric field, the phase acquires macroscopic biaxial ordering resulting from the collective alignment of the domains. A phenomenological theory is developed for the molecular order in this phase and for its transitions to purely uniaxial and to spontaneously biaxial nematic phases.
Functional group dependent dissociative electron attachment to simple organic molecules
Authors: Prabhudesai Vaibhav S. , Nandi Dhananjay , Kelkar Aditya H. , Krishnakumar E.
Published: April 2008

Dissociative electron attachment (DEA) cross sections for simple organic molecules, namely, acetic acid, propanoic acid, methanol, ethanol, and n-propyl amine are measured in a crossed beam experiment. We find that the H− ion formation is the dominant channel of DEA for these molecules and takes place at relatively higher energies (>4eV) through the core excited resonances. Comparison of the cross sections of the H− channel from these molecules with those from NH3, H2O, and CH4 shows the presence of functional group dependence in the DEA process. We analyze this new phenomenon in the context of the results reported on other organic molecules. This discovery of functional group dependence has important implications such as control in electron induced chemistry and understanding radiation induced damage in biological systems.
Turbo charging time-dependent density-functional theory with Lanczos chains
Authors: Rocca Dario , Gebauer Ralph , Saad Yousef , Baroni Stefano
Published: April 2008

We introduce a new implementation of time-dependent density-functional theory which allows the entire spectrum of a molecule or extended system to be computed with a numerical effort comparable to that of a single standard ground-state calculation. This method is particularly well suited for large systems and/or large basis sets, such as plane waves or real-space grids. By using a superoperator formulation of linearized time-dependent density-functional theory, we first represent the dynamical polarizability of an interacting-electron system as an off-diagonal matrix element of the resolvent of the Liouvillian superoperator. One-electron operators and density matrices are treated using a representation borrowed from time-independent density-functional perturbation theory, which permits us to avoid the calculation of unoccupied Kohn–Sham orbitals. The resolvent of the Liouvillian is evaluated through a newly developed algorithm based on the nonsymmetric Lanczos method. Each step of the Lanczos recursion essentially requires twice as many operations as a single step of the iterative diagonalization of the unperturbed Kohn–Sham Hamiltonian. Suitable extrapolation of the Lanczos coefficients allows for a dramatic reduction of the number of Lanczos steps necessary to obtain well converged spectra, bringing such number down to hundreds (or a few thousands, at worst) in typical plane-wave pseudopotential applications. The resulting numerical workload is only a few times larger than that needed by a ground-state Kohn–Sham calculation for a same system. Our method is demonstrated with the calculation of the spectra of benzene, C60 fullerene, and of chlorophyll a.
Multiplicative cross-correlated noise induced escape rate from a metastable state
Authors: Chaudhuri Jyotipratim Ray , Chattopadhyay Sudip , Banik Suman Kumar
Published: April 2008

We present an analytical framework to study the escape rate from a metastable state under the influence of two external multiplicative cross-correlated noise processes. By starting from a phenomenological stationary Langevin description with multiplicative noise processes, we have investigated the Kramers theory for activated rate processes in a nonequilibrium open system (one dimensional in nature) driven by two external cross-correlated noise processes which are Gaussian, stationary, and delta correlated. Based on the Fokker–Planck description in phase space, we then derive the escape rate from a metastable state in the moderate to large friction limit to study the effect of degree of correlation on the same. By employing numerical simulation in the presence of external cross-correlated additive and multiplicative noises, we check the validity of our analytical formalism for constant dissipation, which shows a satisfactory agreement between both the approaches for the specific choice of noise processes. It is evident both from analytical development and the corresponding numerical simulation that the enhancement of rate is possible by increasing the degree of correlation of the external fluctuations.
Disorder and decision cost in spatial networks
Authors: Zanin Massimiliano , Buldú Javier M. , Cano P. , Boccaletti S.
Published: April 2008

We introduce the concept of decision cost of a spatial graph, which measures the disorder of a given network taking into account not only the connections between nodes but their position in a two-dimensional map. The influence of the network size is evaluated and we show that normalization of the decision cost allows us to compare the degree of disorder of networks of different sizes. Under this framework, we measure the disorder of the connections between airports of two different countries and obtain some conclusions about which of them is more disordered. The introduced concepts (decision cost and disorder of spatial networks) can easily be extended to Euclidean networks of higher dimensions, and also to networks whose nodes have a certain fitness property (i.e., one-dimensional).
Observation of structural transitions and Jahn–Teller distortion in LaMnO3-doped BiFeO3 thin films
Authors: Kartopu G. , Lahmar A. , Habouti S. , Solterbeck C-L. , Elouadi B. , Es-Souni M.
Published: April 2008

Structural and functional properties of multiferroic BiFeO3 are currently under debate. We utilized Raman spectroscopy to characterize the structural properties of pure and up to 10mol% LaMnO3-doped polycrystalline BiFeO3 thin films. All films were identified as phase-pure perovskite using x-ray diffraction (XRD). Although XRD has insufficient sensitivity for detailed thin film analysis, Raman experiments showed that pure BiFeO3 structure is best described as monoclinic, and that doping with LaMnO3 causes substantial modifications, namely, Jahn–Teller distortions to the (Mn,Fe)3+O6 octahedra accompanied by structural transition toward orthorhombic. Manganese substitution is shown to be the main cause of these changes.