The cholestyramine-induced decrease of PYY postprandial response is negatively correlated with fat mass in obese women.

Obese patients have decreased fasting and postprandial levels of peptide YY (PYY), an anorexigenic peptide produced by the L cells of the gastrointestinal mucosa. Fatty nutrients are the most powerful stimulus for PYY release. Cholestyramine, an anion exchanger which adsorbs bile salts, reduces digestion of lipids. The aim of the present study was to investigate the effects of cholestyramine or placebo on PYY secretion in obese women administered a high-fat meal [n=8; age: 30.9±2.7 years; BMI: 47.3±3.3 kg/m2]. Postprandial PYY levels in obese women given placebo significantly increased in plasma at 30, 60, 90, and 120 min after meal ingestion. Cholestyramine administration significantly reduced postprandial PYY response at 15, 30, and 60 min. Percent fat mass (FM%) was negatively correlated with the percent increment of plasma PYY concentrations induced by meal administration at 30 min; conversely, there was a positive correlation between FM% and the percent decrement of plasma PYY concentrations induced by cholestyramine at the same time interval. These correlations failed to reach statistical significance when related to BMI. This study implies that in the obese state the altered PYY response to food consumption is a consequence of a dysfunction of L cells, which become less sensitive to the positive feedback effect of lipids.

Prediction of resting energy expenditure in severely obese Italian males.

The objectives of the present study were to develop and cross-validate new equations for predicting resting energy expenditure (PREE) in severely obese Italian males, and to compare their accuracy with those of the Harris-Benedict, WHO/ FAO/UNU, Huang, Owen, Mifflin, Livingston, Nelson, Bernstein, and Cunnimgham equations in order to predict resting energy expenditure (REE), using the Bland-Altman method. One hundred and sixty-four severely obese males [mean body mass index (BMI): 45.4 kg/m2; 50.2% fat mass), aged 20 to 65 yr participated in this study. REE was measured by indirect calorimetry and body composition by bioelectrical analysis. Equations were derived by stepwise multiple regression analysis using a calibration group and tested against the validation group. Two new specific equations, based on anthropometric [REE=Weight x 0.048 + Height x 4.655 - age x 0.020 - 3.605 (R2=0.68, SE=1.14 MJ/d)] or body composition parameters [REE=fat free mass (FFM) x 0.081 + fat mass (FM) x 0.049 - age x 0.019 - 2.194 (R2=0.65, SE=1.15 MJ/d)], were generated. Mean PREE were not different from the mean measured REE (MREE) (<1%, p<0.001), REE being predicted accurately (95-105% of MREE) in 66 and 62% of subjects, respectively. The Harris-Benedict, WHO/FAO/UNU, Huang and Owen equations showed mean differences lower than 5% and PREE was accurate in less than 30% of subjects. The Mifflin, Livingston, and Nelson equations showed a mean PREE underestimation >7% (p<0.001) and PREE was accurate in less than 25% of subjects. The Bernstein and Cunningham equations showed a greater PREE underestimation (>22%, p<0.001) in more than 85% of subjects. The new prediction equations allow an accurate estimation of REE in groups of severely obese males and result in lower mean differences and lower limits of agreement between PREE and MREE than the commonly used equations.

Postural instability of extremely obese individuals improves after a body weight reduction program entailing specific balance training.

The purposes of this study were to compare postural stability between obese and lean subjects and to investigate the effect of a 3-week body weight reduction (BWR) program entailing specific balance training on postural stability of extremely obese patients. Time of balance maintenance and mean error on the medial-lateral direction at the trunk and lower limb level were assessed during a single limb stance on a movable platform in 19 non-obese and in 20 extremely obese individuals (age range: 20-40 yr). Time of balance maintenance was shorter (obese: 21.1+/-7.7 vs lean: 27.3+/-3.1 sec) and medial-lateral sway of the trunk was larger in obese (5.4+/-3.2 degrees) than in lean (3.2+/-1.1 degrees) subjects (p<0.05). Two subgroups of obese subjects were also tested after a BWR program (energy-restricted diet, moderate physical exercise, nutritional education and psychological counselling) combined with or without 6 sessions of specific balance training on a movable platform. BWR plus specific balance training enhanced time of balance maintenance (pre: 23.8+/-7.2 vs post: 30.0+/-0.0 sec) and reduced the trunk sway (5.2+/-2.8 degrees vs 2.6+/-0.9 degrees ) more than BWR alone (p<0.05). The present findings indicate that extremely obese individuals have inadequate postural stability (compared to their lean counterparts) that could however be improved by few sessions of specific balance training incorporated into a multidisciplinary BWR program. It was concluded that balance improvement is an important goal of rehabilitation, that would probably reduce the propensity of overweight individuals to fall while performing everyday activities.

Ghrelin secretion in severely obese subjects before and after a 3-week integrated body mass reduction program.

Ghrelin, the endogenous ligand of GH-secretagogue receptors, has been implicated in the regulation of feeding behavior and energy balance. Aim of the study was to investigate ghrelin levels in fasting conditions and after a standard meal test in obese subjects before and after a 3-week integrated body weight reduction (BWR) program (consisting of energy-restricted diet, exercise training, psychological counselling and nutritional education). Weight, height, fat mass, fat free mass (by impedentiometry), circulating ghrelin, insulin and leptin levels were evaluated in 10 obese subjects (3 male, 7 female; mean age: 35 +/- 9.3 yr; body mass index BMI: 45.2 +/- 10.6 kg/m2) before and after weight reduction. At baseline, obese subjects showed significantly lower ghrelin levels than controls, which were negatively correlated with BMI, weight, insulin and leptin levels. Fasting ghrelin levels were not modified by standard meal test in obese subjects (from 110.8 +/- 69.7 to 91.8 +/- 70.2 pmol/l p=ns), while a significant reduction was observed in controls (from 352.4 +/- 176.7 to 199.0 +/- 105.2 pmol/l; p<0.01). After a 3-week integrated BWR program obese subjects significantly reduced weight, BMI and leptin levels, while no significant changes were found both in fasting ghrelin and in ghrelin response after the meal. In conclusion, 5% weight loss obtained after a short-term period of integrated BWR program is not sufficient to normalize fasting ghrelin levels nor to restore the normal ghrelin suppression after a meal in severely obese subjects.

Effects of non-specific vs individualized exercise training protocols on aerobic, anaerobic and strength performance in severely obese subjects during a short-term body mass reduction program.

The purpose of the present study was to compare aerobic, anaerobic and strength performance changes induced by two short-term (3-week) body mass reduction programs based on the same low-calory diet (1200-1500 kcal/day), nutritional education and psychological counseling, but entailing different exercise training protocols. An individualized, low-volume and moderate-intensity exercise training (IET) was contrasted with a non-specific, high-volume, low-intensity exercise training (NET). Thirty obese in-patients (12 males, 18 females; mean age +/- SD: 33.9 +/- 9.4 yr, range: 19-51yr; mean BMI: 40.5 +/- 3.8 kg/m2, range: 35.3-51.4 kg/m2) were randomly divided in two gender-matched groups of 15 subjects each undergoing a different exercise training protocol. Maximum oxygen uptake (VO2max) determined with a submaximal indirect test on a bicycle ergometer, lower limb maximum power output (W(max)) determined with the jumping method, global motor capabilities determined by analysis of locomotor pattern during a short (8 m) running, maximum strength (1-RM) of upper and lower limb muscle groups determined with isotonic machines were tested before and after the program. Adherence to an individual exercise activity and maintenance of body weight (bw) loss were evaluated with a telephonic interview 6 months after the completion of the program. In both groups a significant (p < 0.001) and comparable weight loss was observed (IET: -4.27%; NET: -4.17%). In both groups VO2max and W(max) increased significantly (p < 0.05-0.001) when expressed relatively to body mass, while in absolute terms they were significantly (p < 0.001) improved only in IET group. 1-RM in all tested muscle groups was significantly increased in both IET and NET subjects (p < 0.001-0.01), but improvements were significantly greater in IET as compared with NET (p < 0.05-0.001). The analysis of locomotor pattern during the short running indicated that IET subjects significantly improved their global motor capabilities (p < 0.05-0.001), while no change was observed in NET group. After 6 months, IET subjects reported a level of spontaneously chosen physical activity significantly higher (p < 0.05) than NET subjects, displaying a trend of further decrease in bw. It was concluded that, although no difference in bw loss was appreciated between the two studied groups and significant improvements were found also in subjects performing NET protocol, the IET protocol offers better overall results in terms of muscle performance and physical fitness, with a possibly stronger motivation to subsequent exercise activity.

Effects of a 3-week integrated body weight reduction program on leptin levels and body composition in severe obese subjects.

The effects of short-term (3 weeks) integrated body weight reduction (BWR) program (including energy-restricted diet, aerobic and strength exercise (5 days/week), nutritional education and psychological counseling) on plasma leptin levels and body composition were investigated in 54 morbidly obese patients (38 females/16 males; mean BMI +/- SE: 41.8 +/- 0.1 kg/m2, range 35-58 kg/m2; mean age: 29.8 +/- 1.0 yr, age range: 18-46 yr). The BWR program induced a significant (p < 0.001) weight loss (BMI reduction: -4.8%) and a significant modification in body composition, consisting in a fat mass (FM) decrease (-7.0 +/- 0.4%, p < 0.001) with a concomitant fat-free (FFM) mass increase (1.8 +/- 0.3%, p < 0.001). On average, plasma leptin levels decreased significantly both in males (from 19.4 +/- 2.6 ng/ml to 11.6 +/- 1.3 ng/ml, p < 0.001) and in females (from 41.1 +/- 3.6 ng/ml to 29.9 +/- 3.0 ng/ml, p < 0.001). Both before and after weight loss, leptin levels were positively correlated (p < 0.001) with BMI and percent fat mass (FM) values. Weight changes after the BWR program were negatively correlated with baseline leptin concentrations both in absolute terms and expressed per unit FM. In conclusion, a short-term diet plus aerobic/strength training effectively induces body composition changes and reduces plasma leptin levels. Body FM reduction appears to be not the unique determinant of leptin levels regulation and the degree of leptin over-expression may negatively affect weight loss in morbidly obese patients.

Effects of 12 months rhGH treatment on bone and collagen turnover in children with constitutional growth delay.

Serum bone Gla protein (BGP), marker of osteoblast function, serum carboxyterminal cross-linked telopeptide of type I collagen (ICTP) and urinary free deoxypyridinoline (DPD), markers of bone resorption, and the aminoterminal propeptide of type III procollagen (PIIINP), marker of type III collagen turnover, were determined in eight prepubertal children (8 males, age range 7-9.6 yr, Tanner stage I) with constitutional growth delay (CGD), before and after 6-12 months of treatment with rhGH (Saizen, Serono, 0.6 IU/kg/week, s.c.). Serum BGP (mean+/-SD: 15.4+/-1.7 ng/ml), ICTP (9.4+/-1.6 ng/ml) and urinary DPD/creatinine (11.3+/-1.7 nmol/mmol) levels were significantly lower (p<0.02, p<0.0001 and p<0.02, respectively) in children with CGD than in healthy age-matched controls (BGP: 18.9+/-3.6 ng/ml, ICTP: 14.3+/-2.6 ng/ml, DPD: 20.7+/-10.0 nmol/mmol), while PIIINP levels of patients were similar to those recorded in controls (6.3+/-0.7 vs 6.7+/-2.3 ng/ml, respectively). Serum BGP, urinary free DPD/creatinine and PIIINP levels significantly increased after 6 (BGP: 20.9+/-2.1 ng/ml, p<0.0001; DPD/creatinine: 16.3+/-3.6 nmol/mmol, p<0.001; PIIINP: 8.1+/-1.6 ng/ml, p<0.005) and 12 months (BGP: 19.2+/-2.0 ng/ml, p<0.0001; DPD/creatinine: 19.7+/-5.1 nmol/mmol, p<0.001; PIIINP: 8.8+/-1.9 ng/ml, p<0.002) of GH treatment. Serum ICTP levels did not significantly change after 6 months (10.6+/-2.1 ng/ml), while a significant increase (p<0.002) was evident after 12 months of therapy (13.6+/-1.3 ng/ml). Our study shows that BGP, ICTP and DPD/creatinine levels are significantly reduced in children with CGD, thus indicating the presence of low bone turnover in this form of short stature. Since GH treatment is able to reactivate bone remodeling and increase collagen synthesis, it is tempting to speculate that a partial GH-IGF-I defect (i.e. locally at bone level) might be one of the factors involved in determining the biochemical alterations of bone metabolism found in this clinical condition.

CT appearance of mycotic abdominal aortic aneurysms.

The CT appearance of three cases of infected aortic aneurysms is reported with clinical and pathological correlation. Two of our cases had unique features: the disappearance of aortic calcifications, and an irregular, thickened aortic wall with peripheral enhancement. The nonspecific clinical presentation and high mortality make mycotic aneurysm an important consideration in the differential diagnosis of abnormal soft tissue contiguous with the aorta.