The extraordinary capacity of phytate (myo-inositol hexaphosphate), a substance present in blood, urine, interstitial and intracellular fluids, to inhibit crystallization of calcium salts (oxalate and phosphate) is discussed. Its role in preventing calcium renal stone formation is specifically presented and discussed. "In vitro" and "in vivo" experiments, as well as clinical studies clearly dem...

Over 59 generations, a strain of rats has been inbred to maximize urine calcium excretion. The rats now excrete eight to 10 times as much calcium as controls. These rats uniformly form calcium phosphate (apatite) kidney stones and have been termed genetic hypercalciuric stone-forming (GHS) rats. The addition of a common amino acid and oxalate precursor, hydroxyproline, to the diet of the GHS ra...

Nephrolithiasis is a common clinical disorder, and calcium oxalate (CaOx) is the principal crystalline component in approximately 75% of all renal stones. It is widely believed that proteins act as inhibitors of crystal growth and aggregation. Acidic amino acids present in these proteins play a significant role in the inhibition process. In this study, interaction of calcium oxalate with human ...

BACKGROUND The incidence of kidney stones in children is increasing. While guidelines exist for acute surgical intervention, there is limited data to inform the decision as to when to intervene non-urgently. OBJECTIVES To identify patient and stone characteristics predicting stone surgery in children. DESIGN Retrospective chart review. SETTING Stollery Children's Hospital, Edmonton, Alber...

To assess the binding of individual amino acids to the principal calcium minerals found in human kidney stones, the adsorption of 20 amino acids on to calcium oxalate monohydrate, CaHPO4*2H2O, Ca3(PO4)2 and Ca5(PO4)3OH crystals was determined over the physiological urinary pH range (pH 5-8) in aqueous solutions. All amino acids adsorbed most strongly at pH 5, and this decreased in all cases as ...

The majority of human urinary stones are primarily composed of calcium salts. Although normal urine is frequently supersaturated with respect to calcium oxalate, most humans do not form stones. Inhibitors are among the multiple factors that may influence the complex process of urinary stone formation. We have isolated an inhibitor of calcium oxalate crystal growth from human urine by monoclonal...

PURPOSE Critically evaluate the experimental evidence and clinical trial outcomes as the basis for use of magnesium (Mg) supplements as therapy for calcium oxalate nephrolithiasis. MATERIALS AND METHODS Literature search of MedLine and Web of Science through January 2005; articles cited in papers found by searches. RESULTS Magnesium inhibits calcium oxalate crystallization in human urine an...

Nephrolithiasis is a common health problem across the globe with a prevalence of 15%-20%. Idiopathic hypercalciuria is the most common cause of nephrolithiasis, and calcium oxalate stones are the most common type of stones in idiopathic hypercalciuric patients. Calcium phosphate stones are frequently associated with other diseases such as renal tubular acidosis type 1, urinary tract infections,...

Copyright © 2010 Massachusetts Medical Society. A 43-year-old man presents for evaluation of recurrent kidney stones. He passed his first stone 9 years earlier and has had two additional symptomatic stones. Analysis of the first and the last stones showed that they contained 80% calcium oxalate and 20% calcium phosphate. Analysis of a 24-hour urine collection while the patient was not receiving...