PubMed · 3719967
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R M David, Z K Shihabi, M L O'Connor. 1986. Simplified method for cystinuria screening.. https://pubmed.ncbi.nlm.nih.gov/3719967/
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The uptake of L-cystine into cultured human umbilical vein endothelial cells was Na+ independent and inhibited competitively by glutamate. It is concluded that the uptake of cystine in endothelial cells is mediated by system x-c. The contents of glutathione in endothelial cells decreased when the cells were cultured in cystine-free medium or in glutamate-enriched medium, suggesting that the glutathione level in endothelial cells is regulated by the cystine uptake via system x-c. The uptake rate of cystine increased three times the normal rate when the cells were exposed to H2O2 generated by glucose and glucose oxidase. This increase required protein synthesis. The cystine transport activity was also enhanced when the cells were cocultured with activated polymorphonuclear leukocytes. Intracellular glutathione levels were decreased when the cells were exposed to H2O2 despite an increase in the cystine uptake. The extracellular glutathione levels were increased at that time, suggesting the efflux of glutathione. In endothelial cells, cystine transport activity seems to be involved in the cell defense against oxidative stress.
We evaluated the respective role of size, location and composition of renal stones as determinants of the outcome of extracorporeal shock wave lithotripsy (ESWL). The analysis of the chemical composition and of the morphology of the fragments eliminated by hundred patients who underwent ESWL has been made by X-rays diffraction. Results showed that the larger the stone, the higher the risk of having to perform an extra intervention (additional sessions of ESWL, percutaneous nephrostolithotomy, nephrolitholapaxy) or of finding residual fragments at the three month check-point. In addition, the location of the stone in a calice, especially a lower calice, strongly predisposes to incomplete elimination of the fragments. Finally, two types of stones appear to lessen the probability of success of ESWL: those of struvite and those of cystine. Indeed, out of eleven ESWL performed on struvite stones (pure or mixed), two had to be completed by percutaneous nephrolitholapaxy and even one by a nephrectomy because of superinfection. Out of the four patients with cystine stones, two had to be treated by additional percutaneous nephrolitholapaxy because of inadequate fragmentation after ESWL. However, for the remaining types of stones (pure or mixed) chemical composition seems to be less important than size or location.
We present 31 patients with cystine urolithiasis referred to our extracorporeal shock wave lithotripsy (ESWL) center since 1985. This group differed statistically from the other 3000 patients treated by us for urolithiasis with regard to age, stone burden, number of previous operations, and known duration of urolithiasis. The average known duration in those with cystine stones was 15 years. Of 26 patients with such a history, 22 had an average of 2 operations each. At referral, 14 had bilateral stones and among the others there were 5 nonfunctioning kidneys. Of 26 referred with a diagnosis of cystine nephrolithiasis, only 11 were being treated medically. At presentation, 31 had no stones and 1 was being treated medically. In the other 29 patients, 44 renal-ureteral units had urolithiasis. During follow-up 2 ureteral stones were discharged spontaneously and the other units were treated by ESWL, surgery and/or ureteroscopy, and percutaneous irrigation. 36/42 units were free of significant stone residue, but in 4 there were large gravel remains; 1 kidney was removed primarily and 1 kidney lost its function following prolonged obstruction after ESWL. During follow-up, of 11 patients unable to tolerate D-penicillamine and treated by urinary alkalinization alone, 3 have already formed new stones.