Urinary stone analysis

Amino acids were isolated from natural sources, asparagine from plants, cystine from urinary stones in the first decade of the last century and became known later to be constituents of proteins. The peptide bond, however, as the fundamental feature of protein structure was recognized only in this century (Hofmeister 1902 E. Fischer 1906). Several more decades elapsed until sequence elucidation reached the point of practicality. The turning point was signaled by the determination of the structure of insulin (Sanger et al. 1953). The subsequent development of automated amino acid analysis (Spackman, Stein and Moore 1958) and automatic sequencing (Edman and Begg 1967)... 

X.-H. Sun, L.-M. Shen, X.-M. Cong, H.-J. Zhu, J.-L. Lv, L. He (2011) Infrared spectroscopic analysis of urinary stones (including stones induced by melamine-contaminated milk powder) in 189 Chinese children. J. Pediatric Surgery, 46, 723-728. 

In a French analysis of 22 510 urinary calcuh performed by infrared spectroscopy, drug-induced urolithiasis was divided into two categories first, stones with drugs physically embedded (n = 238 1.0%), notably indinavir monohydrate (n = 126 53%), followed by triamterene n = 43 18%), sulfonamides (n — 29 12%), and amorphous silica (n = 24 10%) secondly. 

In a French analysis of 22 510 urinary calculi performed by infrared spectroscopy, drug-induced urolithiasis was divided into two categories first, stones with drugs... 

A 15-year-old boy with Lennox-Gastaut syndrome taking felbamate (3000 mg/day), topiramate(200 mg/ day), and lorazepam developed painful hematuria, bilateral urethral obstruction, and urinary retention. Kidney, bladder, and urethral stones were found. The stone material was identified as felbamate by chemical analysis. However, as the patient was also taking topir-amate the association with felbamate was uncertain. 

Mandel NS, MandeIGS. Urinary tract stone disease In the United States veteran population. II. Geographical analysis of variations In composition. J.Urol. 1989,142 1516-21. 

The finding of a cystine stone should prompt confirmation of cystinuria by urinary analysis. It could be argued, however, that aU stone formers should be screened for cystinuria at least 10% of cystinurics form stones in which cystine cannot be detected, presumably because of epitaxis. The index of suspicion shordd be increased in patients who are relatively young stone formers and in those with a positive family history. Once a cystinuric patient is diagnosed, it is important to screen all members of the family, particularly to detect affected siblings. 

Spectrophotometric analysis of urinary inhibition on the active forms (HMW-UK and LMW-UK) revealed a significant difference between subjects with and without renal calculi (VI). A positive correlation exists between the percentage of inhibition and the urinary urate concentration. Urate inhibits both the LMW-UK and the HMW-UK, but not plasmin. These results are in perfect agreement with reports that stone patients have higher urinary urate concentrations (C2). These observations may explain why allopurinol is administered to kidney stone patients. Allopurinol causes a decrease in urinary urate excretion by inhibiting the xanthine oxidase, which could cause a higher urinary urokinase activity. 

Renal stones (calculi) produce severe pain and discomfort, and are common causes of obstruction in the urinary tract (Fig. 2). Chemical analysis of renal stones is important in the investigation of why they have formed. Types of stone include ... 

Sharrow, S. D., Novotny, M. V. and Stone, M. J., 2003, Thermodynamic analysis of binding between mouse major urinary protein-I and the pheromone 2-sec-butyl-4,5-dihydrothiazole, Biochemistry 42 6302-6309. 

We examined altogether 17 patients 9 men and 8 women. The patients were aged between 20 and 75 years. Two stones were found in the urine, 15 in the renal pelvis. We selected a patient group with uric acid percentage of 90—100% in the analysis of their urinary calculi. 

As with blood, urine analysis is used in clinical studies, and the relative concentrations of various ionic species are of great importance in both disease diagnostic and drug metabolism studies. For example, IC is used to determine urine oxalate concentrations. Urinary oxalate levels are an important parameter in urolithiasis research (kidney stones). Other anions that can be determined in urine using IC include phosphate, sulfate, bromide, citrate, nitrate, nitrite, and thiosulfate. As with blood and serum samples, both ultrafiltration and centrifugation are often used as sample cleanup steps. 

Case 2 A 67-year-old male with renal stones who died from renal tumors. He had renal stones, but analysis of them was not undertaken. His uric acid level was 0,1 mg/dl, and urinary uric acid excretion was 0.16 mg/day. 

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