Smith S D, Wheeler M A, Weiss R M
Department of Surgery, Yale University School of Medicine, New Haven, Connecticut 06520-8041, USA.
Kidney Int. 1998 Oct;54(4):1331-6. doi: 10.1046/j.1523-1755.1998.00102.x.
Nitroblue tetrazolium (NBT) reduction to formazan has been used as a marker for nitric oxide synthase (NOS). Since inducible NOS activity is elevated in urine from patients with urinary tract infections (UTIs), we investigated the accuracy of NBT reduction as an early predictor of UTIs and quantified the relationship between inducible NOS and NBT.
Urine samples from 434 patients were screened for the presence of UTIs with leukocyte-esterase and nitrite dipsticks and with NBT reduction. The rapid screening results from each test were compared to urine culture results. In addition, NBT reduction parameters were measured in urine pellet at 595 nm after incubation with one of four factors: NOS cofactors, NOS inhibitors, NADH, or superoxide dismutase/catalase.
As a urine screening test for UTIs, NBT reduction was more sensitive with a higher negative predictive accuracy than the nitrite dipstick. NBT reduction also was more specific with a higher positive predictive accuracy and negative predictive accuracy than the leukocyte-esterase dipstick. In infected urine pellet, both NADPH, a NOS cofactor, and NADH increased NBT reduction. Superoxide dismutase/catalase decreased NBT reduction.
Although NOS may not be the only NBT reducing enzyme, rapid, visible reduction of NBT is induced in urine from patients with UTIs.
硝基蓝四氮唑（NBT）还原为甲臜一直被用作一氧化氮合酶（NOS）的标志物。由于尿路感染（UTI）患者尿液中诱导型NOS活性升高，我们研究了NBT还原作为UTI早期预测指标的准确性，并量化了诱导型NOS与NBT之间的关系。
对434例患者的尿液样本进行筛查，通过白细胞酯酶和亚硝酸盐试纸条以及NBT还原检测UTI的存在。将每项检测的快速筛查结果与尿液培养结果进行比较。此外，在与四种因子之一（NOS辅助因子、NOS抑制剂、NADH或超氧化物歧化酶/过氧化氢酶）孵育后，于595nm处测量尿沉渣中的NBT还原参数。
作为UTI的尿液筛查试验，NBT还原比亚硝酸盐试纸条更敏感，阴性预测准确性更高。NBT还原比白细胞酯酶试纸条也更具特异性，阳性预测准确性和阴性预测准确性更高。在感染的尿沉渣中，NOS辅助因子NADPH和NADH均增加NBT还原。超氧化物歧化酶/过氧化氢酶降低NBT还原。
虽然NOS可能不是唯一使NBT还原的酶，但UTI患者尿液中可诱导NBT快速、明显还原。
