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Biomedical subjects

A Pietrobelli

Publications and source records attributed to A Pietrobelli.

78 records · Page 5Linked to original sources
PubMed1996

Influence of body composition on bone mineral content in children and adolescents.

Excess fat and fat-free mass have been extensively described in obese children, whereas few data about bone mineral content (BMC) variations are available in children. Dual-energy X-ray absorptiometry (DXA) allows a direct and accurate measurement of three body compartments (fat, lean, and BMC), subdivided into three regions (arms, trunk, and legs). The aim of our study was to evaluate the influence of body compartments on total BMC (TBMC) and regional BMC (RBMC) in obese and normal-weight subjects. Sixty-five obese and 50 normal-weight children and adolescents (age range: 5-18 y relative body weight: 160 +/- 23% and 101 +/- 12%, respectively), matched for sex and pubertal stage underwent a DXA total-body analysis. Obese subjects had significantly greater fat and lean compartments than normal-weight subjects (P < 0.0001). TBMC was larger in obese children (1930 +/- 670 g compared with 1480 +/- 490 g, P < 0.0001) as was RBMC (arms: 182 +/- 81 g compared with 151 +/- 65 g; trunk: 560 +/- 223 g compared with 433 +/- 169 g; legs: 788 +/- 341 g compared with 539 +/- 231 g, P < 0.0001). We found lean mass to be the best correlate with TBMC (r = 0.91 in obese and 0.94 in normal-weight children). Multiple-regression analysis confirmed lean mass as one of the major determinants of TBMC and RBMC in children. However, differences in TBMC and RBMC were no longer present after correction for age, sex, and body-composition variables. There were no differences in TBMC and RBMC between obese and normal-weight children after correction for the confounding variables age and sex.

Absorptiometry, Photon↗
PubMed1996

Dual-energy X-ray absorptiometry body composition model: review of physical concepts.

Although dual-energy X-ray absorptiometry (DXA) is widely used in clinical research as a means of quantifying body composition, there remains at present little published information that reviews the method's underlying physical basis. Because a clear understanding of DXA physical concepts is integral to appropriate use and interpretation, we present here a three-section review that includes both relevant in vitro and in vivo experimental demonstrations. In the first section we describe the main physical principles on which DXA is based. The section that follows presents a step-by-step analysis of the DXA two-component soft tissue model. In the final section we demonstrate how knowledge of physical concepts can lead to resolution of important methodological concerns, such as the influence of hydration changes on DXA fat estimates. A thorough understanding of DXA physical concepts provides a basis for appropriate interpretation of measurement results and stimulates many new and important research questions.

Absorptiometry, Photon↗
PubMedDate not supplied

Upper extremity skeletal muscle mass: potential of measurement with single frequency bioimpedance analysis.

This study examined the potential of single frequency (50 kHz) BIA for estimation of upper extremity skeletal muscle (SM) mass. Subjects (n = 50) were weight stable adults varying in age (X +/- SD, 51.6 +/- 17 yr) and body mass index (27.2 +/- 5.9 kg/m2). Determinants of arm to arm impedance index (length L; L2/Z) were examined using multiple regression analysis. A good correlation was observed between L2/Z and arm SM estimated by dual-energy X-ray absorptiometry (r = 0.88, p < 0.001). Additional significant model covariates were arm fat mass (p < 0.05), bone mass (p < 0.01), and age (p < 0.001). These findings suggest that upper extremity SM may be rapidly and easily quantified using a simple and inexpensive BIA system combined with appropriate age-adjusted impedance prediction equations.

Absorptiometry, Photon↗
PubMedDate not supplied

Lean R value for DXA two-component soft-tissue model: influence of age and tissue or organ type.

Dual-energy X-ray absorptiometry (DXA) is an important new body composition method that is based on tissue attenuation of two main photon energies. When the two photon energies pass through tissue, attenuation at the lower energy compared with that at the higher energy can expressed as a ratio (R), which is used for tissue component identification. We tested whether: (1) the R value of lean tissue is related to age, and (2) the R value of lean tissue differs between soft tissue locations. Elemental content of various tissues from the literature was used. Results show that lean R values for 40 keV and 70 keV are independent of age and tissue type.

Absorptiometry, Photon↗
PubMedDate not supplied

Congenital true pancreatic cyst in pediatric age: case report.

Congenital pancreatic cysts are rare lesions in pediatric age. We present a case of congenital true pancreatic cyst in otherwise asymptomatic boy aged 4 years. Clinical history, laboratory, imaging, immunohistological findings and surgical treatment are also described.

Biopsy↗