Nakagawa Y, Netzer M, Michaels E K, Suzuki F, Ito H
Department of Medicine (Nephrology Program), University of Chicago, Illinois.
J Urol. 1994 Jul;152(1):29-34. doi: 10.1016/s0022-5347(17)32808-2.
Nephrocalcin, an acidic glycoprotein that inhibits calcium oxalate crystal growth, has been previously localized in proximal tubules of kidneys by an immunohistochemical staining method and purified from tissue culture media of 2 renal carcinoma cell lines. A polyclonal antibody specific to nephrocalcin was raised in rabbits and the level of nephrocalcin was quantitatively determined in urine of 19 renal cell carcinoma patients (0.241 +/- 0.341 microgram nephrocalcin per mg. creatinine) and compared to healthy controls (0.022 +/- 0.012 micrograms nephrocalcin per mg. creatinine). Nephrocalcin levels after tumor nephrectomy decreased dramatically in 5 patients and to a lesser degree in 7. A specific nephrocalcin fraction that was eluted from an anion exchange column with low ionic strength was detected in urine of the renal cell carcinoma patients, and this fraction decreased or disappeared after tumor nephrectomy in 6 of 9 patients studied. Amino acid composition, phosphate content and dissociation constants toward calcium oxalate monohydrate crystals were investigated in the nephrocalcin from tumor patients and compared to that from healthy controls. Our studies demonstrate that nephrocalcin in patients with renal cell carcinoma is atypical and usually in much higher quantity. Further studies are needed to determine the clinical significance of these observations.
肾钙蛋白是一种抑制草酸钙晶体生长的酸性糖蛋白，此前已通过免疫组织化学染色方法定位在肾脏近端小管中，并从2种肾癌细胞系的组织培养基中纯化出来。用兔制备了针对肾钙蛋白的多克隆抗体，并对19例肾细胞癌患者尿液中的肾钙蛋白水平进行了定量测定（每毫克肌酐含0.241±0.341微克肾钙蛋白），并与健康对照者（每毫克肌酐含0.022±0.012微克肾钙蛋白）进行了比较。5例患者肿瘤肾切除术后肾钙蛋白水平显著下降，7例患者下降程度较小。在肾细胞癌患者的尿液中检测到一种从阴离子交换柱以低离子强度洗脱的特定肾钙蛋白组分，在9例研究患者中的6例中，该组分在肿瘤肾切除术后降低或消失。对肿瘤患者的肾钙蛋白进行了氨基酸组成、磷酸盐含量和对一水合草酸钙晶体的解离常数的研究，并与健康对照者的进行了比较。我们的研究表明，肾细胞癌患者的肾钙蛋白是不典型的，通常数量要高得多。需要进一步研究来确定这些观察结果的临床意义。
