Although physical activity is known to improve bone mineralization, it is unclear whether this occurs through altered absorption and/or excretion. The purpose of this study was to investigate the effects of a high-impact and resistance-training exercise program versus a period of restricted physical activity on urinary calcium excretion. Ten healthy, moderately active men (27.0 +/- 5.8 yr) part...

The formation of various types of kidney stones is strongly influenced by urinary pH. An alkaline pH favors the crystallization of calcium- and phosphate-containing stones, whereas and acidic urine pH promotes uric acid or cystine stones. The activity of many transport processes involved in calcium, citrate and phosphate handling are sensitive to changes in systemic or local pH as shown for sev...

One of the obstacles in analyzing frozen urine samples is the formation of uncharacterized precipitates. Frequently, these precipitates are discarded before analysis. Some laboratory data may be erroneous if these precipitates contain important compounds. In the present study, we examined urinary sediments precipitated after overnight storage at -20 degrees C. Although cells and debris were rem...

Background. Skeletal fragility is a complication of phenylketonuria (PKU). A diet containing amino acids compared with glycomacropeptide reduces bone size and strength in mice. Objective. We tested the hypothesis that amino acid medical foods (AA-MF) provide a high dietary acid load, subsequently increasing urinary excretion of renal net acid, calcium, and magnesium, compared to glycomacropepti...

OBJECTIVE To evaluate the effect of dietary supplementation with sodium chloride (NaCl) on urinary calcium excretion, urine calcium concentration, and urinary relative supersaturation (RSS) with calcium oxalate (CaOx). ANIMALS 6 adult female healthy Beagles. PROCEDURE By use of a crossover study design, a canned diet designed to decrease CaOx urolith recurrence with and without supplemental...

Administration of oral contraceptive (OC) has been associated with body fluid retention and in high doses over a long period, promotes hypertension. This present investigation tests the hypothesis that the dietary calcium supplementation increases salt and water excretion in OC (norgestre/ethinylestradiol) treated 32 female albino rats randomly distributed into four (1-4) groups of 8 rats each:...

To clarify the role of the intestine, kidney, and bone in maintaining calcium homeostasis during pregnancy and lactation and after the resumption of menses, a longitudinal comparison was undertaken of 14 well-nourished women consuming approximately 1200 mg Ca/d. Measurements were made before conception (prepregnancy), once during each trimester of pregnancy (T1, T2, and T3), early in lactation ...

The abundance of protein in the matrix of calcium oxalate uroliths has fueled speculation regarding its role in stone genesis. In this study, we wanted to characterize the composition of the proteins associated with early stages of calcium oxalate crystallization in urine. Calcium oxalate crystallization was induced in urine from healthy men and women by the addition of an oxalate load. The cry...

PURPOSE Urolithiasis develops more frequently in patients with a family history (FHx). However, little is known about risk factors in stone formers with a FHx. The aim of this study was to examine the clinico-metabolic characteristics of urinary stone formers according to FHx. MATERIALS AND METHODS A database of 1,068 stone formers who underwent a complete metabolic evaluation was reviewed. T...

OBJECTIVES Calcium oxalate kidney stones are more common in patients with Crohn's disease (CD). The aims of this study were to verify the prevalence of the main risk factors for calcium oxalate nephrolithiasis in patients with CD and to evaluate the degree of urinary relative supersaturation for calcium oxalate (CaOx), dihydrogen uric acid (DHUA) and monohydrogen calcium phosphate (MHCaP). SUBJ...