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Cimolin V.,Polytechnic of Milan | Cimolin V.,Orthopaedic Rehabilitation Unit | Galli M.,Polytechnic of Milan | Vismara L.,Orthopaedic Rehabilitation Unit | And 3 more authors.
International Journal of Rehabilitation Research | Year: 2015

Obesity is the most common chronic disorder in children and adolescents. As walking is the most common daily task and is recommended for weight management, quantifying how obesity affects the biomechanics of gait provides important insight into the relationship between metabolic and mechanical energetics, mechanical loading and associated risk for musculoskeletal injury. This study quantitatively compared gait in 12 obese and 10 lean adolescents. Obese adolescents showed longer stance duration, excessive hip flexion during the whole gait cycle and an increased hip movement in the frontal plane compared with lean participants. In the obese, the knee was slightly extended in stance phase and the ankle was in a plantar flexed position at initial contact and at toe-off, with a greater ankle range of motion. Kinetic data showed higher values of maximum power generated at hip level during the stance phase; ankle power displayed a higher absorption at initial stance and higher values of power generation in the terminal stance. Because obese adolescents are encouraged to walk to increase their physical activity and energy expenditure level, injury prevention and rehabilitative programmes should take our findings into consideration and include specific strengthening of the lower limb proximal and distal muscles, together with weight loss and reconditioning interventions. © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Bizzarri C.,Unit of Endocrinology and Diabetes | Rigamonti A.E.,University of Milan | Luce A.,University of Insubria | Cappa M.,Unit of Endocrinology and Diabetes | And 5 more authors.
European Journal of Endocrinology | Year: 2010

Background and aims: Ghrelin is an orexigenic 28-amino acid peptide produced by the stomach. Circulating ghrelin levels rise shortly before and fall shortly after every meal. Peptide YY (PYY), an anorexigenic 36-amino acid peptide, is secreted primarily from the intestinal mucosa of the ileum and large intestine. Plasma PYY levels begin to rise within 15 min after starting to eat and plateau within -90 min, remaining elevated for up to 6 h. Recently, some studies have tried to evaluate the potential role of ghrelin and PYY in the hyperphagia of patients with Prader-Willi syndrome (PWS). While hyperghrelinemia is well characterized in PWS, conflicting results have been reported for PYY. The aim of the study was to investigate ghrelin and PYY responses to a standard liquid high-fat meal in children with PWS. Patients and methods: Circulating levels of total ghrelin and PYY levels were assayed by RIA after overnight fasting and 45, 60, 90, and 180 min following a standard meal (Ensure 6 ml/kg) in 16 patients with PWS (11 boys and five girls, aged 4.6-10.7 years, including ten receiving 0.02 mg/kg per day rhGH for 2-18 months; body mass index (BMI) z-score: 0.6±0.2 and 1.6±0.5 for children treated or not treated with rhGH respectively), ten obese (eight boys and two girls, aged 9.2-15.6 years; BMI z-score: 2.4±0.2, i.e. BMI > 97th centile for chronological age and sex) subjects, and 16 normal-weight controls (five boys and 11 girls, aged 5.8-17.3 years; BMI z-score: 0.6±0.2). Results: PWS children showed higher fasting levels of ghrelin than obese and lean controls. Postprandial ghrelin drop was more pronounced in PWS than in the other study groups. No significant difference on fasting levels of PYY was found among groups. PWS showed a higher postprandial PYY rise than obese and lean controls.PWSpatients treated and not treated with GH showed similar fasting and postprandial levels of ghrelin and PYY. Fasting PYY levels correlated negatively (P<0.05; r=-0.68) with those of ghrelin only in PWS. Conclusions: The results of this study confirm fasting hyperghrelinemia in PWS. Since in PWS adults an impaired postprandial suppression of plasma ghrelin was previously reported to be associated with a blunted postprandial PYY response, the finding of a meal-induced decrease and increase in ghrelin and PYY levels respectively in PWS children would imply that the regulation of appetite/satiety of these peptides is operative during childhood, and it progressively deteriorates and vanishes in adulthoodwhen hyperphagia and obesity worsen. © 2010 European Society of Endocrinology.

Bedogni G.,Liver Research Center | Bedogni G.,University of Milan | Grugni G.,Istituto Auxologico Italiano | Agosti F.,Experimental Laboratory for Auxo endocrinological Research | And 3 more authors.
Obesity Facts | Year: 2014

Objective: Patients with Prader-Willi syndrome (PWS) have been hypothesized to be at lower risk of non-alcoholic fatty liver disease (NAFLD) because of higher insulin sensitivity. However, PWS patients have a peculiar body composition, i.e. higher fat mass and lower fat-free mass, which may confound such associations. We evaluated whether NAFLD is less frequent in PWS than in non-PWS women matched on percent body fat (PBF). Methods: PBF was measured by dual-energy X-ray absorptiometry. Liver fat was assessed by ultrasonography. Insulin sensitivity and beta-cell function were evaluated by oral glucose tolerance testing. Coarsened exact matching (CEM) was used to match PWS and non-PWS women on PBF. General and generalized linear models taking CEM into account were used to perform comparisons between PWS and non-PWS women. Results: 20 women with PWS were matched to 27 women without PWS on the basis of PBF (mean 53 vs. 54%, p = 0.6). Insulin sensitivity and beta-cell function were similar in the two groups. However, the prevalence of NAFLD was 25% in PWS versus 59% in non-PWS women (p = 0.04). Conclusion: NAFLD is less frequent in PWS than in non-PWS women but this finding is not associated with higher insulin sensitivity. © 2014 S. Karger GmbH, Freiburg.

Bedogni G.,Clinical Epidemiology Unit | Bedogni G.,University of Milan | Agosti F.,Experimental Laboratory for Auxo endocrinological Research | De Col A.,Experimental Laboratory for Auxo endocrinological Research | And 3 more authors.
European Journal of Clinical Nutrition | Year: 2013

Background/Objectives: We evaluated the agreement of air displacement plethysmography (ADP) and bioelectrical impedance analysis (BIA) with dual-energy X-ray absorptiometry (DXA) for the assessment of percent fat mass (%FM) in morbidly obese women. Subjects/Methods: Fifty-seven women aged 19-55 years and with a body mass index (BMI) ranging from 37.3 to 55.2 kg/m 2 were studied. Values of %FM were obtained directly from ADP and DXA, whereas for BIA we estimated fat-free mass (FFM) from an equation for morbidly obese subjects and calculated %FM as (weight-FFM)/weight. Results: The mean (s.d.) difference between ADP and DXA for the assessment of %FM was -2.4% (3.3%) with limits of agreement (LOA) from -8.8% to 4.1%. The mean (s.d.) difference between BIA and DXA for the assessment of %FM was 1.7% (3.3%) with LOA from -4.9% to 8.2%. Conclusion: ADP-DXA and BIA-DXA are not interchangeable methods for the assessment of body composition in morbidly obese women. Copyright © 2013 Macmillan Publishers Limited.

Salvadego D.,University of Udine | Sartorio A.,Istituto Auxologico Italiano | Sartorio A.,Experimental Laboratory for Auxo endocrinological Research | Agosti F.,Experimental Laboratory for Auxo endocrinological Research | And 5 more authors.
European Journal of Applied Physiology | Year: 2015

Purpose: In obesity, an increased work of breathing contributes to a higher O2 cost of exercise and negatively affects exercise tolerance. The purpose of the study was to determine whether, in obese adolescents, acute respiratory muscle unloading via normoxic helium–O2 breathing reduces the O2 cost of cycling and perceived exertion. Methods: Nine males [age 16.8 ± 1.6 (x ± SD) years, body mass 109.9 ± 15.0 kg] performed on a cycle ergometer, breathing room air (AIR) or a 21 % O2–79 % helium mixture (He–O2): an incremental exercise, for determination of $$ \mathop V\limits^{.} $$V.O2 peak and gas exchange threshold (GET); 12 min constant work rate (CWR) exercises at 70 % of GET (GET) determined in AIR. Results: $$ \mathop V\limits^{.} $$V.O2 peak was not different in the two conditions. From the 3rd to the 12th minute of exercise (both during CWR < GET and CWR > GET), $$ \mathop V\limits^{.} $$V.O2 was lower in He–O2 vs. AIR (end-exercise values: 1.40 ± 0.14 vs. 1.57 ± 0.22 L min−1 GET). During CWR > GET in AIR, $$ \mathop V\limits^{.} $$V.O2 linearly increased from the 3rd to the 12th minute of exercise, whereas no substantial increase was observed in He–O2. The O2 cost of cycling was ~10 % (GET) lower in He–O2 vs. AIR. Heart rate and ratings of perceived exertion for dyspnea/respiratory discomfort and leg effort were lower in He–O2. Conclusions: In obese adolescents, acute respiratory muscle unloading via He–O2 breathing lowered the O2 cost of cycling and perceived exertion during submaximal moderate- and heavy-intensity exercise. © 2014, Springer-Verlag Berlin Heidelberg.

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