Urine proteins are thought to control calcium oxalate stone formation, but over 1000 proteins have been reported in stone matrix obscuring their relative importance. Proteins critical to stone formation should be present at increased relative abundance in stone matrix compared to urine, so quantitative protein distribution data were obtained for stone matrix compared to prior urine proteome data. Matrix proteins were isolated from eight stones (> 90% calcium oxalate content)

BTURB was associated with a lower risk of overall complications, but there was no difference in the rate of hematuria in the two cohorts. Male gender and large tumor size are associated with higher risk of early complications.

Purpose. To determine the association between the two methods of obtaining current perception thresholds (CPTs) in the lower urinary tract (LUT). Materials and Methods. Twenty-one women undergoing pelvic surgery underwent CPT determinations of the urethra. CPTs were measured at 2,000, 250, and 5 Hz (corresponding to A-β, A-δ, and C fibers, resp.) both pre- and postoperatively. Threshold values were obtained in all patients by using the method of limits and the method of levels. Results. CPT values obtained by using the method of levels and the methods of limits were highly correlated at all frequencies before and after surgery (ρ = 0.93–0.99, P < 0.0001). The mean threshold values obtained by the method of levels were significantly lower at all frequencies compared with those obtained by the method of limits. Conclusions. Our findings suggest that the method of levels is more sensitive for the detection of CPTs compared to the method of limits.

Despite the apparent importance of matrix proteins in calcium oxalate kidney stone formation, the complexity of the protein mixture continues to elude explanation. Based on a series of experiments, we have proposed a model where protein aggregates formed from a mixture containing both strongly charged polyanions and strongly charged polycations could initiate calcium oxalate crystal formation and crystal aggregation to create a stone. These protein aggregates also preferentially adsorb many weakly charged proteins from the urine to create a complex protein mixture that mimics the protein distributions observed in patient samples. To verify essential details of this model and identify an explanation for phase selectivity observed in weakly charged proteins, we have examined primary structures of major proteins preferring either the matrix phase or the urine phase for their contents of aspartate, glutamate, lysine and arginine; amino acids that would represent fixed charges at normal urine pH of 6–7. We verified enrichment in stone matrix of proteins with a large number of charged residues exhibiting extreme isoelectric points, both low (pI<5) and high (pI>9). We found that the many proteins with intermediate isoelectric points exhibiting preference for stone matrix contained a smaller number of charge residues, though still more total charges than the intermediate isoelectric point proteins preferring the urine phase. While other sources of charge have yet to be considered, protein preference for stone matrix appears to correlate with high total charge content.

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