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Abstract

Human renal calculi surgically removed from kidney stone patients were obtained and chemically analysed. Stones with CaOx (calcium oxalate) as the major component were washed in 0.15 M NaCl with gentle stirring for 48 h and then pulverised to a fine powder. The powder was extracted with 0.05 M EGTA, 1 mM PMSF and 1% beta-mercaptoethanol for 4 days at 4 degrees C, the suspensions and the supernatants obtained were filtered through an Amicon Model 200 apparatus (mol. wt. cut off of 10,000 daltons) under nitrogen at 40 p.s.i. and concentrated to a known volume. The method of Nakagawa et al. [7] was employed to study the ability of > 10 kDa fractions to influence COM growth using metastable solution of CaCl2 and Na2C2O4 containing traces of 14C-oxalic acid. Potent biomolecules having the ability to influence CaOx precipitation were subjected to isolation, purification and characterization. Standard biochemical procedures, e.g. ultracentrifugation, ion-exchange chromatography, molecular sieve chromatography and SDS-PAGE, etc., were employed. Results revealed that human renal calculi extract contains biomolecules that can inhibit as well as stimulate the growth of preformed COM (calcium oxalate monohydrate) crystals. Most potent stimulator of CaOx growth was found to have a molecular weight of 66 kDa.

Peeping into Human Renal Calcium Oxalate Stone Matrix: Characterization of Novel Proteins Involved in the Intricate Mechanism of Urolithiasis

“…The supernatant of EGTA extract was filtered through Amicon ultra centrifugal filter device with 3kDa molecular weight cut off at 4°C and concentrated it. Whole EGTA extract and greater than 3 kDa fractions were stored at −20°C for further studies [15].…”

Nephrolithiasis: Molecular Mechanism of Renal Stone Formation and the Critical Role Played by Modulators

“…Our research group has been conducting many studies to explore the organic matrix of renal stone and revealed the presence of a 66 kDa stimulator of calcium oxalate crystal growth in the human renal calculi extract [6]. Later they investigated the activity of high and low molecular weight biomolecules present in the matrix of human CaOx stones not only on the initial mineral phase formation of calcium and phosphate (CaP) but also on its growth and demineralization of the preformed mineral phase [226].…”

“…However, approximately 75% of stones are primarily calcium oxalate, but up to 50% of these include calcium hydroxyl phosphate (brushite or calcium hydroxyapatite) in trace or greater amounts; 10–20% are composed of magnesium ammonium phosphate (struvite or triple phosphate); 5% are composed of urate; and 1-2% are composed of cystine [4, 5]. With its multifactor etiology and high rate of recurrences, urinary tract stone disease provides a medical challenge [6]. There is thus a pressing need to prevent this disease and its recurrence.…”

Evaluation of Antiurolithiatic Activity of Asparagus Racemosus on In Vitro Calcium Oxalate Crystallization Methods

“…The solutions of 7. accomplished by comparing the turbidity slope of the varying concentrations of cystone or AEAR with the control by the succeeding formula. 15 However Tsi was the nucleation turbidity slope in the existence of an inhibitor sample, i.e., cystone/AEAR and Tsc was the nucleation turbidity slope in the absence of the inhibitor (control).…”