Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0451641 (urolithiasis)
 3,973 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extreme degrees of hypoxanthine phosphoribosyltransferase (HPRT) deficiency in man are associated with gross sex-linked neurological dysfunction, gout and urinary stones (the Lesch-Nyhan or 'complete HPRT-deficiency' syndrome). The less severe degrees of enzyme deficiency (sex-linked recessive gout and/or urolithiasis or the 'partial HPRT-deficiency' syndrome) may be associated with minor neurological manifestations. Whole body purine synthesis de novo is accelerated in both these groups of patients. A strain of mice with an experimentally produced mutation at the HPRT locus showed some residual 'apparent HPRT activity' in brain, liver, testicular, splenic, kidney and ovarian tissues but not in erythrocyte haemolysates. The mutation removes exons 1 and 2 of the coding region of the gene together with the promotor and about 10 kb of upstream sequence from the gene. It is therefore possible that the observed 'apparent HPRT activity' in these mice is due to the operation of an alternative metabolic pathway. Purine synthesis de novo was markedly accelerated in their brain, testicular, splenic and kidney tissues. It was not accelerated in the liver tissue of male mice hemizygous for the mutation and the degree of acceleration in the female homozygotes only just reached statistical significance at the p = 0.02 level. This observation casts doubt on the importance of modulations in the rate of hepatic purine synthesis de novo as a mechanism for maintaining a steady supply of purines for translocation to other organs.
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PMID:Purine synthesis de novo and salvage in hypoxanthine phosphoribosyltransferase-deficient mice. 209 36

The epidemiology of renal stones has changed all over the world toward a predominance of calcium oxalate stones. However, studies evaluating the influence of age and gender on the distribution of the various types of urinary calculi are scarce. We will present the results of a study based on 205 calculi (from 122 boys and 83 girls) analyzed by infrared spectroscopy between 1993 and 2007. 90% of stones were collected by surgery, whereas only 6% by spontaneous passage. The biological exploration was performed in only 126 cases. Etiology was metabolic in 13.5%. 10.7% of stones were infectious, 13.1% were endemic and 54.9% were idiopathic. 7.8% were secondary to urinary stasis with malformation but no infection. Calcium oxalate (CaOx) was the predominant constituent in 54.7% of stones, followed by calcium phosphate and purines 14.6% in each of the cases. We found an increasing prevalence of calcium oxalate stones with age in both genders (42.9% in infant vs. 59.3% in child) (P < 0.05). Struvite stones were more frequent in infant than children. Purine stones were predominant in 20% of cases, but its prevalence decreases with age. The increase in calcium oxalate stone in school age children and the decrease in struvite and purine stones confirm the change on the etiology of urolithiasis according to age.
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PMID:Changes in stone composition according to age in Tunisian pediatric patients. 1993 17