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In cases where volume of urine is significantly reduced or if abnormally high amounts of crystal-forming salts are present (hyperuricosuria) the concentration levels reach the point at which the salts no longer dissolve, so they precipitate out and form crystals.
 

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Hyperuricosuria is defined as urinary uric acid levels that exceed 800 mg/day in men and 750 mg/day in women. The most common cause of hyperuricosuria is increased dietary purine intake, but many other hereditary or acquired factors (eg, gout) may result in this condition. Individuals with hyperuricosuria may develop uric acid or calcium oxalate stones due to supersaturation of urine with monosodium urate. Monosodium urate may initiate calcium oxalate stone formation by the induction of heterogeneous nucleation or by absorption of certain inhibitors. Patients with calcium oxalate stones have a urinary pH of greater than 5.5.

Reference:
http://emedicine.medscape.com/article/444866-overview
 

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Discussion Starter · #5 ·
hey thanku so much :)
but still i dont get one thing, if oxalate stones are formed when ph > 5 n uric acid decreases pH, how they form ! from that link i think maybe somehow monosodium urate must be increasing urinary pH.
 

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hey thanku so much :)
but still i dont get one thing, if oxalate stones are formed when ph > 5 n uric acid decreases pH, how they form ! from that link i think maybe somehow monosodium urate must be increasing urinary pH.
Uric acid decreases urine PH but when you have oxalate stones in urine (which are formed because of the presence of monosodium urate) the urine PH goes high even though the patient is having hyperuricosuria.
 

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Or maybe: at a urine pH <5.5 hyperuricosuric patients are more likely to form uric acid stones, and at a urine pH >5.5 hyperuricosuric patients are more likely to form calcium stones?
 

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Discussion Starter · #8 ·
@mondoshawan, yea possible. i dont know, thats y i posted. i asked few of my friends, no one was actually kinda sure. il try to look up sm place else. u try too.
n hey i read ur ques that alpha 1 antitrypsin one, it was good one !
 
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