The influence of varying blood and dialysate flow on haemodialysis adequacy

The aim of this study was the exploration and correlation of the influence of variations in blood flow and dialysate flow on haemodialysis adequacy through the quantitative indexes Kt/V, TACurea and PCR. A prospective study of 48 patients subjected to haemodialysis was carried out. The collection of data included taking blood and urine samples according to the directives of DOQI, for a total of 8 months. Statistical analysis was based on the paired t-test and multiple regression analysis. The variations in blood flow and dialysate flow are positively related to the variation of the indexes Kt/V, TACurea and PCR and consequently to the haemodialysis adequacy both as isolated factors and when combined together

Bone mineral content of junior competitive weightlifters

It is suggested that practicing various sports can increase the bone mineral content (BMC). However, we were unable to find any reports indicating BMC changes in weightlifting, a sport which involves both extremities and spine and increases muscle mass as well. Therefore, we thought that it might be of interest to measure BMC in junior competitive weightlifters. On the occasion of a recent Junior World Championship we measured, by single photon absorptiometry, BMC in 59 young competitive male athletes (aged 15 to 20 years) from 14 countries. Several variables were taken into account for each subject, including race, record, age, height and weight. Multiple regression analysis was performed in order to assess the contribution of the above mentioned variables to the variability of both distal and proximal BMC. Finally, athletes' BMCs were compared to matched sex and age normals. Our results suggest that junior competitive weightlifters have an increased BMC, well above the age-matched controls' mean. It seems that the vigorous exercise of weightlifters tends to fade out any race or age-related BMC differences. Finally, weightlifters' BMC seems to be highly correlated with body weight and record

Body composition changes in chronic hemodialysis patients before and after hemodialysis as assessed by dual-energy X-ray absorptiometry

The aim of this study was to investigate the effect of hemodialysis on body composition assessment by dual-energy x-ray absorptiometry (DEXA). Seventeen patients with chronic renal failure who were on a regular hemodialysis schedule were studied. Body weight and body composition were assessed immediately before and approximately 1 hour after a typical hemodialysis session. Body weight was assessed by means of an electronic balance. Body composition measurements were made by DEXA. Whole-body and subtotal (head and neck excluded) analysis assessed the following parameters: body weight, bone mineral density (BMD), bone mineral content (BMC), and fat (FTM)and lean (LTM) tissue mass. BMC, FTM, and LTM were estimated separately for the trunk, arms, and legs. The mean body weight reduction after hemodialysis was 2.8 +/- 1.1 kg (mean +/- SD). Concerning whole-body analysis, no change was observed in mean BMC and FTM after hemodialysis. On the contrary, a significant reduction was observed in mean body weight as assessed by DEXA (before hemodialysis, 65.0 +/- 11.4 kg; after, 62.2 +/- 10.9 kg, P=.0003), as well as in mean LTM (before hemodialysis, 42.7 +/- 9.4 kg; after, 39.7 +/- 9.0 kg, P=.0003). Similar results were obtained from subtotal and regional analysis. Body weight changes as measured by the electronic balance exhibited a strong positive correlation with the changes in both body weight and LTM as assessed by DEXA (r=.989, standard error of the estimate [SEE]=0.167 kg and r=.941, SEE=0.382 kg, respectively, P<.0001). It is concluded that gravimetric changes induced by hemodialysis are highly correlated with LTM changes and are not associated with changes in BMC or FTM estimated by DEXA. Copyright (C) 1997 by W.B. Saunders Company

Exercise, Nutrition, and Bone Health

Optimal bone metabolism is the result of hormonal, nutritional, and mechanical harmony, and a deficit in one area is usually impossible to overcome by improvements in others. Exercise during growth influences bone modeling locally at the regions being loaded, whereas calcium is thought to act systemically to influence bone remodeling. Despite acting through different mechanisms, a growing body of research suggests that exercise and calcium may not operate independently. Low dietary calcium intake or reduced bioavailability may minimize the adaptive response to exercise-induced bone loading. Conversely, adequate levels of calcium intake can maximize the positive effect of physical activity on bone health during the growth period of children and adolescents. Research also suggests that adequate levels of calcium intake can maximize bone density at the regions being loaded during exercise. Achieving optimal bone health and minimizing one’s risk of osteoporotic fracture later in life depend on a lifelong approach. This approach relies on the establishment of an optimum level of bone during the growth years, with a subsequent goal to maintain and slow the rate of age-related bone loss thereafter. Exercise, adequate nutrition, and optimal hormone levels are the components that influence the bone outcome. Making healthy nutritional choices, engaging in weight-bearing physical activity, and ensuring optimal hormone levels during growth provides a window of opportunity to build optimal bone mass, to reduce the risk of fracture later in life. Concurrent management of fracture risk with a physical activity prescription, adequate nutrition, and pharmacotherapy for osteoporosis when required offers the best approach to optimal bone health throughout adulthood