Guerra A, Borghi L, Meschi T, Novarini A
Istituto di Semeiotica Medica, Università degli Studi di Parma.
Acta Biomed Ateneo Parmense. 1990;61(1-2):85-90.
Ion exchange chromatography is the best method for the determination of cysteine in urine, but it requires an expensive apparatus, specialized technicians and a long time. The major colorimetric procedure is the nitroprusside color reaction first described by Brand, but it involves the reaction with toxic cyanide reagent. Moreover commercial stick are not available. We have experienced a colorimetric procedure in which the sulfhydryl group of cystine reduces phosphotungstic acid to tungstic blue, which is determined photometrically. This procedure avoids the use of cyanide. We used this screening test during 5 years of ambulatory evaluation of nephrolithiasis and we found these results: urine cystine 191 controls: 87 +/- 57 mg/day, 870 stone oxalate and uric acid patients: 99 +/- 57 mg/day, 11 stone cystine patients: 479 +/- 379 mg/day (p 0.001). A close correlation was found in stone cystine patients between our data obtained in the same sample with ion exchange chromatography. We conclude that this inexpensive and simple method can be recommended as a screening test for cystinuria.
离子交换色谱法是测定尿中半胱氨酸的最佳方法，但它需要昂贵的仪器、专业技术人员且耗时较长。主要的比色法是布兰德首次描述的硝普盐显色反应，但它涉及与有毒的氰化物试剂反应。此外，没有商用试纸条。我们经历了一种比色法，其中胱氨酸的巯基将磷钨酸还原为钨蓝，通过光度法进行测定。该方法避免了使用氰化物。我们在对肾结石进行5年门诊评估期间使用了这种筛查试验，得到了以下结果：191名对照者尿胱氨酸：87±57毫克/天，870名草酸钙和尿酸结石患者：99±57毫克/天，11名胱氨酸结石患者：479±379毫克/天（p<0.001）。在胱氨酸结石患者中，我们用离子交换色谱法在同一样本中获得的数据之间发现了密切相关性。我们得出结论，这种廉价且简单的方法可推荐作为胱氨酸尿症的筛查试验。
