Creatine supplement in combination with exercise increased the proportion of lean mass more than EX or CREAT alone. The use of creatine alone induced an important and significant reduction of both RPF and GFR.

Metabolic evaluation of stone-forming (SF) patients is based on the determination of calcium, oxalate, citrate, uric acid and other parameters in 24-h urine samples under a random diet. A reliable measurement of urinary oxalate requires the collection of urine in a receptacle containing acid preservative. However, urinary uric acid cannot be determined in the same sample under this condition. Therefore, we tested the hypothesis that the addition of preservatives (acid or alkali) after urine collection would not modify the results of those lithogenic parameters. Thirty-four healthy subjects (HS) were submitted to two non-consecutive collections of 24-h urine. The first sample was collected in a receptacle containing hydrochloric acid (HCl 6 N) and the second in a dry plastic container, with HCl being added as soon as the urine sample was received at the laboratory. Additionally, 34 HS and 34 SF patients collected a spot urine sample that was divided into four aliquots, one containing HCl, another containing sodium bicarbonate (NaHCO(3 )5 g/l), and two others in which these two preservative agents were added 24 h later. Urinary oxalate, calcium, magnesium, citrate, creatinine and uric acid were determined. Urinary parameters were also evaluated in the presence of calcium oxalate or uric acid crystals. Mean values of all urinary parameters obtained from previously acidified 24-h urine samples did not differ from those where acid was added after urine collection. The same was true for spot urine samples, with the exception of urinary citrate that presented a slight albeit significant change of 5.9% between samples in HS and 3.1% in SF. Uric acid was also not different between pre- and post-alkalinized spot urine samples. The presence of crystals did not alter these results. We concluded that post-delivery acidification or alkalinization of urine samples does not modify the measured levels of urinary oxalate, calcium, magnesium, creatinine and uric acid, and that the change on citrate was not relevant, hence allowing all parameters to be determined in a single urine sample, thus avoiding the inconvenience and cost of multiple 24-h urine sample collections.

Background/Aim: Some studies have identified an association of kidney stone formation with vitamin D receptor (VDR) or calcium-sensing receptor (CaSR) polymorphisms. We aimed to evaluate the association between these polymorphisms with urinary calcium excretion (uCa) in calcium- stone-forming patients. Methods: VDR polymorphism, detected by BsmI digestion, and 3 CaSR polymorphisms (G/T at codon 986, G/A at codon 990 and C/G at codon 1011), detected by direct sequencing, were evaluated in 100 hypercalciuric (HCa) and 101 normocalciuric (NCa) calcium-stone-forming patients. Results: The total allelic frequency of VDR polymorphism was: 16% BB, 49% Bb and 35% bb. The prevalence of bb genotype was significantly higher in the HCa when compared to the NCa group (43 vs. 27%). With respect to CaSR polymorphisms, 986S, 990G and 1011E variant alleles were detected, respectively, in 5, 4 and 3% of the whole sample and 5 CaSR haplotypes were identified: 94% ARQ (wild-type), 3% SRQ, 1.5% AGQ, 1.0% ARE and 0.5% AGE. No statistical differences have been observed between NCa and HCa with respect to these CaSR haplotypes. Conclusions: The present study suggested that bb homozygous for VDR polymorphism was overrepresented in hypercalciuric stone formers. Urinary calcium excretion was not associated with CaSR polymorphism in the present sample.

The estrogen receptor (ER) gene has been considered as a candidate genetic marker for osteoporosis, and PvuII and XbaI polymorphisms of the ERalpha gene have been associated with low bone mineral density (BMD). We investigated whether ER polymorphism could predict the response of BMD in 28 postmenopausal women on hemodialysis with marked osteopenia or osteoporosis, randomized to receive raloxifene, a selective estrogen receptor modulator (SERM), or placebo for 1 year. BMD was assessed by dual X-ray absorptiometry and PvuII and XbaI restriction fragment-length polymorphism of the ER gene was determined using polymerase chain reaction. Baseline lumbar spine or femoral neck BMD parameters were not different between patients presenting either homozygous PP or xx when compared with heterozygous Pp or Xx genotypes. After 1 year, patients on raloxifene, presenting with PP or xx genotypes (but not those with Pp or Xx), showed a significantly higher mean lumbar spine BMD (0.942 +/- 0.18 vs. 0.925 +/- 0.17 g/cm2, p < .01) and lower serum pyridinoline (19.7 +/- 9.7 vs. 30.6 +/- 16.5 nmol/L, p < .02) when compared with baseline values. No changes were detected in the placebo-treated patients or in the femur neck sites. In conclusion, after 1 year on raloxifene, postmenopausal osteoporotic women on chronic hemodialysis, homozygous for the P or x (PP or xx) alleles of the ER, exhibited a better lumbar spine BMD response and decreased serum pyridinoline values when compared with heterozygous women (Pp or Xx), suggesting that ERalpha allelic variants may explain, at least in part, the different outcomes after treatment of osteoporosis with SERM.

The estrogen receptor (ER) gene has been considered as a candidate genetic marker for osteoporosis, and PvuII and XbaI polymorphisms of the ERalpha gene have been associated with low bone mineral density (BMD). We investigated whether ER polymorphism could predict the response of BMD in 28 postmenopausal women on hemodialysis with marked osteopenia or osteoporosis, randomized to receive raloxifene, a selective estrogen receptor modulator (SERM), or placebo for 1 year. BMD was assessed by dual X-ray absorptiometry and PvuII and XbaI restriction fragment-length polymorphism of the ER gene was determined using polymerase chain reaction. Baseline lumbar spine or femoral neck BMD parameters were not different between patients presenting either homozygous PP or xx when compared with heterozygous Pp or Xx genotypes. After 1 year, patients on raloxifene, presenting with PP or xx genotypes (but not those with Pp or Xx), showed a significantly higher mean lumbar spine BMD (0.942 +/- 0.18 vs. 0.925 +/- 0.17 g/cm2, p < .01) and lower serum pyridinoline (19.7 +/- 9.7 vs. 30.6 +/- 16.5 nmol/L, p < .02) when compared with baseline values. No changes were detected in the placebo-treated patients or in the femur neck sites. In conclusion, after 1 year on raloxifene, postmenopausal osteoporotic women on chronic hemodialysis, homozygous for the P or x (PP or xx) alleles of the ER, exhibited a better lumbar spine BMD response and decreased serum pyridinoline values when compared with heterozygous women (Pp or Xx), suggesting that ERalpha allelic variants may explain, at least in part, the different outcomes after treatment of osteoporosis with SERM.