Biomedical subjects

V Giantin

Publications and source records attributed to V Giantin.

6 recordsLinked to original sources

PubMed2000

Visceral fat loss evaluated by total body magnetic resonance imaging in obese women operated with laparascopic adjustable silicone gastric banding.

OBJECTIVE: To investigate the changes of visceral fat, as compared with total and subcutaneous adipose tissue (AT) in obese patients operated with laparascopic adjustable silicone gastric banding (LAP-BAND). SUBJECTS: Six premenopausal morbid obese (body mass index range: 41.4-44.2 kg/m2) women, aged 38-42 y, operated with LAP-BAND, evaluated before, 8 weeks after, and 24 weeks after surgery. MEASUREMENTS: Fat distribution was analysed by total body multi-slices MRI. Total AT, gluteo-femoral subcutaneous AT, abdominal subcutaneous AT, and abdominal visceral AT volumes were measured. FM was calculated from MRI-determined total AT volume and AT density. RESULTS: A weight loss of 9.9+/-3.8 kg was observed in the first 8 weeks after LAP-BAND (0-8 weeks), and a further weight loss of 7.1+/-4.9 kg in the subsequent 16 weeks (8-24 weeks). Total AT showed a statistically significant reduction of 6.2+/-4.0 l in 0-8 weeks and a further significant reduction of 7.7+/-3.9 l in 8-24 weeks (P<0.01 from baseline). A similar trend was observed for both abdominal and gluteo-femoral subcutaneous AT. Visceral AT showed a statistically significant reduction of 1.0+/-0.9 l in the 0-8 weeks (P<0.05) and a further non-significant reduction of 0.6+/-0.7 l in 8-24 weeks (P<0.05 from baseline). In 0-8 weeks, the relative reduction of visceral AT was higher than the relative reduction of both total AT and gluteo-femoral subcutaneous AT. A highly significant correlation was observed between the reduction of total AT and the reduction of both abdominal and gluteo-femoral subcutaneous AT. By contrast, in 0-8 weeks, the reduction of total AT and the reduction of visceral AT were not correlated. In a subsequent analysis, both observations collected in the first 8 weeks after LAP-BAND and observations collected in the last 16 weeks are simultaneously considered, leading to a total of 12 time periods (two time periods for each individual patient). In order to identify factors associated with preferential visceral fat reduction, we calculated for each of the 12 time periods the difference between the percentage changes of visceral AT and the percentage changes of total AT. The relationship between this difference and several other variables were investigated by simple correlation analysis. The only variables found to be associated were the initial visceral AT volume, the absolute level of weight loss (kg) per week of observation, and the relative level of weight loss (%) per week of observation. CONCLUSION: In the phase of rapid weight loss following LAP-BAND, a preferential mobilization of visceral fat, as compared with total and subcutaneous AT, can occur. However, this preferential visceral fat reduction occurs only in those patients presenting higher levels of visceral fat deposition at baseline and higher levels of weight loss. International Journal of Obesity (2000)24, 60-69

Abdomen↗

PubMed1995

Relationship between energy expenditure and visceral fat accumulation in obese women submitted to adjustable silicone gastric banding (ASGB).

OBJECTIVE: To analyze the relationship between visceral fat accumulation and resting energy expenditure in obese women and to evaluate the effects of a severe weight loss both on energy expenditure and on fat distribution. DESIGN: Twelve premenopausal women, aged 19-50 years, undergoing adjustable silicone gastric banding (ASGB) for morbid obesity participated at the study. The patients were evaluated twice. The baseline evaluation was performed immediately before surgery. After surgery, a diet specifically developed for patients submitted to gastric restriction (2.5 MJ/day) was given to the patients. The second evaluation was performed 6 months after surgery. MEASUREMENTS: Resting metabolic rate (RMR) was determined by indirect calorimetry. Total fat area (TFA), visceral fat area (VFA) and subcutaneous fat area (SFA) were measured by abdominal computed tomography. Fat mass (FM) and fat free mass (FFM) were derived by bioelectrical impedance analysis. RESULTS: At baseline, RMR was positively related to VFA (r = 0.60, P < 0.05). ASGB induced a highly significant weight loss of 24.4 +/- 9.0 kg. This weight reduction was mainly due to a loss of FM (68.5 +/- 10.8 vs 48.5 +/- 9.2 kg, P < 0.001), whereas FFM was only slightly reduced (52.6 +/- 4.0 vs 47.9 +/- 4.6 kg, P < 0.05). The BMI reduction was positively related to the baseline BMI and FM values (r = 0.61, P < 0.05 and r = 0.55, P < 0.05, respectively). There was no significant correlation between the BMI reduction and the baseline variables of fat distribution, nor between the BMI reduction and the basal RMR. Weight loss was accompanied by modifications of fat distribution. In particular, the reduction of VFA after surgery was strictly related to the VFA values at baseline (r = 0.91, P < 0.001). Weight loss induced a significant reduction of RMR (7.96 +/- 1.77 vs 6.57 +/- 6.90 MJ/day; P < 0.01). The reduction of the RMR observed with weight loss was significantly related to the FFM loss (r = 0.63, P < 0.05), whereas no correlations were found between the changes of RMR and the FM loss. Regarding to fat distribution, the reduction of the RMR was significantly related to the visceral fat loss (r = 0.57, P < 0.05), but not to the modifications of total or subcutaneous fat area. The independent contribution of the modifications of FFM, FM, and visceral fat to the changes of RMR was analyzed by multiple regression analysis. In this model, both FFM and visceral fat changes resulted independently related to the RMR. CONCLUSIONS: (1) visceral fat accumulation was a significant predictor of RMR in the very obese woman; (2) visceral obese women lost more visceral fat than subcutaneous ones; (3) the reduction of the RMR observed during weight loss could partly be explained by a reduction of visceral fat mass.

Adipose Tissue↗

PubMed1994

Accuracy of bioelectrical impedance analysis in estimation of extracellular space in healthy subjects and in fluid retention states.

Bioelectrical impedance analysis (BIA) is a noninvasive method recently introduced for body fluid evaluation in healthy subjects. The purpose of this paper is to verify the reliability of bioelectrical measurements in extracellular water (ECW) prediction in healthy subjects and in fluid retention states. We studied 40 subjects (19 males and 21 females) aged 21-81 years; 22 were healthy subjects, 12 were affected by chronic heart failure, and 6 by chronic renal failure. In all subjects resistance (R) and reactance (Xc) at 1 and 50 kHz corrected for height were compared with ECW measured by the bromide dilution method. Our results suggested a different behavior of the current in fluid-retention states with respect to healthy subjects. ECW was best predicted by resistance at 1 kHz corrected for height, group (considered as dummy variable), weight and gender (R2 = 0.89, p < 0.001, SEE = 1.7 liters). The bioelectrical impedance analysis at 50 kHz explained the 89% of ECW variability when resistance and reactance corrected for height are considered with gender group and weight (R2 = 0.89, p < 0.001, SEE = 1.7 liters). In conclusion, the bioelectrical method at 1 kHz can be considered sufficiently accurate in ECW prediction in healthy subjects and in fluid retention states. Also, the bioelectrical impedance analysis at 50 kHz is useful for predicting ECW, but his role must be further investigated.

Adult↗

PubMed1993

Body composition study in the elderly: comparison between tritium dilution method and dual photon absorptiometry.

BACKGROUND: The methods commonly employed in body composition study in elderly persons derive fat-free mass (FFM) by measures of total body water (TBW); these methods assume FFM hydration constant (TBW/FFM = 0.732). The aim of our study was to verify the accuracy of the TBW method in FFM estimation and to study the variability of fat-free mass hydration (TBW/FFM) in healthy elderly subjects. METHODS: We assessed FFM in 27 healthy old subjects (76 +/- 7 yrs) by dual photon absorptiometry (DPA) and by TBW measured by 3H2O. Furthermore, to verify the accuracy in FFM estimation by our methods, we measured resting metabolic rate (RMR) by indirect calorimetry. RESULTS: FFM hydration was 71.9 +/- 4.9 (range 63.6-80.4%), a range larger than that reported by direct chemical analysis in adults. The FFM hydration measured in our subjects was not different from the 73.2 value currently used in healthy adults. FFM values derived by TBW (assuming TBW/FFM = 0.732) were not significantly different from FFM measured by DPA. We correlated FFM with resting metabolic rate and found a similar correlation between RMR and FFM-DPA (r = .89, p < .001) and FFM-TBW (r = .85, p < .001). CONCLUSIONS: Both methods employed in our study have proved to be accurate in estimating FFM in elderly persons; particularly, the value of 0.732 assigned to FFM hydration to derive fat-free mass in adults can be employed also in body composition study of the elderly.

Absorptiometry, Photon↗

PubMedDate not supplied

Assessment of body composition in elderly: accuracy of bioelectrical impedance analysis.

BACKGROUND: In the literature there are several body impedance analysis (BIA) prediction equations generally determined in younger populations and their accuracy in the elderly has not been adequately confirmed. OBJECTIVE: We verified the reliability of the BIA method in a body composition study in the elderly. METHODS: To assess the accuracy of bioelectrical impedance analysis we compared this method with dual photon absorptiometry (DPA), assumed as a gold standard; body composition was predicted by seven BIA prediction equations in 24 healthy elderly individuals. RESULTS: The best equation in fat-free mass (FFM) estimation is the RJL System formula (published by Segal in 1988); nevertheless, the wide range of the error in FFM estimating may limit its clinical application. The FFM hydration variability seems to be the principal variable which explains the error in FFM estimation by BIA prediction equations. CONCLUSION: These findings indicate that the use of BIA equations is not interchangeable, when FFM is calculated in an elderly population, and more validation studies are necessary in this age group to evaluate the clinical application of this method.

Absorptiometry, Photon↗

PubMedDate not supplied

Heart rate and metabolic response to burn injury in humans.

BACKGROUND: Although frequently done, estimating the energy requirements of individual burn patients without measuring their resting metabolic rate is a less than satisfactory method of evaluation. METHODS: We tested whether heart rate, which relates to the energy expenditure during physical activity, is also associated with postburn hypermetabolism (calculated as percentage increase of resting metabolic rate above the predicted normal fasting resting metabolic rate). Twenty-three patients [12 men and 11 women, aged 38 +/- 13 years (mean +/- SD); weight, 71.6 +/- 14.8 kg; body mass index, 25.4 +/- 3.6; total burn surface area, 35.3 +/- 17.8% (percentage of body surface)] were studied weekly for 3 weeks after an overnight fast. RESULTS: Measured resting metabolic rates and heart rates were 2016 +/- 497 kcal/d, 101 +/- 13 bpm (n = 19); 2231 +/- 485 kcal/d, 107 +/- 13 bpm (n = 18); and 1903 +/- 598 kcal/d, 99 +/- 14 bpm (n = 11) for weeks 1, 2, and 3, respectively. Postburn hypermetabolism was +36% +/- 19%, +55% +/- 27%, and +36% +/- 35% in the first, second, and third week, respectively. In each week postburn hypermetabolism correlated with heart rate (r = 0.65, p = .003; r = 0.69, p = .001; and r = 0.80, p = .002, respectively). Only in the second week did postburn hypermetabolism correlate with total burn surface area (r = 0.52, p = .02); there was no correlation with body temperature. In a multiple regression analysis, predicted resting metabolic rate, heart rate, and total burn surface area together explained 77% of all of the variance observed in the 48 fasting resting metabolic rates that were measured in the study (r2 = 0.77, p < .0001), and each of these variables also had a significant partial correlation with fasting resting metabolic rates (r2 = 0.45, p < .0001; r2 = 0.29, p < .0001; and r2 = 0.03, p < .03, respectively). CONCLUSIONS: In burn patients, variability in heart rate is associated with a significant part of postburn hypermetabolism variability. Therefore, heart rate may be considered a useful variable to be used for the evaluation of the energy requirements of severely burned patients.

Adolescent↗