Bioelectrical impedance analysis (BIA) was used to determine total body water (TBW) and lean body mass (LBM) in patients with renal failure. The body's electrical resistance (R) was measured by the voltage to current ratio, injecting an 800microA alternating current with a frequency of 50KHZ and detecting a voltage drop between the wrist and the ankle. Impedance index (Height2/Resistance) compared favorably with TBW measured by deuterium (D2O) dilution method as the reference, giving the correlation coefficient (r) of 0.966 and standard error estimation (SEE) of 2.71 liter. The index was compared with LBM determined by dual-energy x-ray absorptiometry (DEXA) as the reference, giving r of 0.970 and SEE of 3.00kg. The r of 0.985 and SEE of 2.15kg were found between the reference method. BIA appeared to have a somewhat lower accuracy than those of the reference method. However, it is a useful clinical tool for estimating body composition, because it is easy, rapid and non-invasive. The existing BIA method is based on an extremely simple conductor model of the body. The accuracy may be improved further, based on a more realistic model for the body.
Absorptiometry, Photon ; Ankle ; Body Composition ; Body Water* ; Deuterium ; Electric Impedance* ; Humans ; Renal Insufficiency* ; Wrist

Following extensive bowel resection， the intestinal tract undergoes a variety of adaptive responses to enhance bowel function． The purpose of this study was to determine the effect of glutamine-supplemented parenteral nutrition on mucosal cellularity and gut function． In addition， enterocyte gene expression of two relevant systems was also characterized and related to the structural and functional changes that occurred．Male Wistar rats underwent a 60％ small bowel resection and jugular vein catheterization and were randomized into two groups． The control group （n＝10） received a standard intravenous nutritional solution and the study group （n＝10） received a similar solution but enriched with alanylglutamine dipeptide． After 7 days blood was taken for amino acid analysis， and bowel was harvested to determine mucosal morphology and expression of mucosal cell glutaminase and IGF-I mRNA． Mesentery lymphnodes were cultured to determine the presence of bacteria and thus access bacteria translocation． Serum glutamine concentration and mucosal architecture were maintained in the study group compared to the controls． Seventy percent of lymphnodes were cultured positive in control vs． only 20％ in the study group （P＜0．05）． Jejunal mucosal glutaminase and ileum mucosal IGF-I mRNA increased twofold and threefold respectively compared to control animals．Parenteral nutrition supplemented with alanyl-glutamine dipeptide supports mucosal cellularity and regional immune function in rodents following intestinal resection， These alterations are associated with enhanced enterocyte expression of glutaminase and IGF-I． These changes may facilitate the structural and functional alterations which were observed in the glutamine treated animals．