Immunonephelometric quantification of specific urinary proteins versus a simple electrophoretic method for characterizing proteinuria

OBJECTIVES: The quantification of urinary proteins presenting different molecular sizes is useful in characterizing a proteinuria. We assessed the performance of an electrophoretic system, the Hydragel Urine Profile, which allows firstly the identification of proteinuria and secondly a qualitative detection of monoclonal free light chains (FLC). DESIGN AND METHODS: Initially, the proteinuria was characterized on 127 pathological urines by quantifying albumin, a1microglobulin, immunoglobulins G by immunonephelometric quantification technique and the results were compared with the protein pattern obtained by the electrophoretic method. Secondly, we assessed the sensitivity and specificity of this electrophoretic test for the detection and characterization of Bence Jones proteins. FLC were analyzed quantitatively by an immunonephelometric assay and qualitatively by the electrophoretic test in 150 urines. RESULTS: The agreement between the two methods was good with a percentage of homology for characterizing the proteinuria of 89%. For detecting a monoclonal FLC, the electrophoretic method demonstrated a lesser sensitivity but a higher specificity compared to the immunoassay. CONCLUSION: The Urine Profile kit is a reliable assay that can be used as a screening test to differentiate the type of proteinuria.     

Screening for proteinuria in Japanese schoolchildren: a new approach.

By governmental mandate, Japanese school children are screened annually for proteinuria, hematuria, and glucosuria to identify children with possible renal disorders. We added urine dipstick tests for albumin and creatinine to the Japanese screening protocol, and used their dipstick results for blood, glucose and protein. The sulfosalicylic acid precipitation test was used to confirm "trace" positive protein dipsticks. The Japanese and our screening protocol have in common the same data for glucosuria and proteinuria. Their scheme has an algorithm for repeat testing of children with abnormal results, and further testing and medical evaluation for those showing persistently abnormal values. Out of the 23,121 students, we found seven with likely nephritis, one with confirmed nephritis, one with nephrotic syndrome, 170 with persistent unexplained hematuria, 19 with persistent unexplained proteinuria, 14 cases of urinary tract infection, and 20 cases of likely diabetes mellitus. We conclude that dipstick testing for albumin, protein, creatinine, glucose and occult blood has significant value in a multilevel testing scheme for identifying children with urinary tract abnormalities or diabetes. The assay of albumin increases the sensitivity of the screening, and dividing the albumin by the creatinine concentration reduces the potential errors arising from concentrated or dilute urines.     

非浓缩尿蛋白电泳在肾脏疾病早期诊断的应用探讨

目的 了解肾脏疾病尿蛋白电泳的改变。方法 应用十二烷基磺酸钠-琼脂糖凝胶电泳技术分析肾脏疾病患者非浓缩尿液样本。结果 42例中27例为肾小球性蛋白尿，15例为混合性蛋白尿。结论 非浓缩尿蛋白电泳能早期敏感的检测尿蛋白组分变化，协助临床判断肾脏病变的严重程度。     

Bioactivity of glomerular ultrafiltrate during heavy proteinuria may contribute to renal tubulo-interstitial lesions: evidence for a role for insulin-like growth factor I.

Clinical and experimental data have indicated that heavy proteinuria in renal glomerular diseases is associated with the formation of tubulo-interstitial fibrosis and contributes to the progression of renal failure. Albumin in glomerular ultrafiltrate does not appear to cause this sequelae, rather than compounds that are associated with ultrafiltered plasma proteins. One such protein-bound factor could be insulin-like growth factor I (IGF-I). The present studies show that in nephrotic rats, IGF-I is ultrafiltered in conjunction with IGF-binding protein-2 and is present in proximal tubular fluid at 1.35 nM. Proximal tubular fluid from nephrotic rats autophosphorylates IGF-I receptors in cultured proximal tubular cells. Nephrotic, but not control, rat proximal tubular fluid increases the [3H]thymidine incorporation in cultured tubular cells, and neutralizing IGF-I-receptor antibodies partially inhibit this activity. Incubation of cultured proximal tubular cells with an extract that was prepared from nephrotic rat urine increases the secretion of collagen types I and IV. Secretion of the two collagens is in part ameliorated by neutralizing IGF-I-receptor antibody. In concert, these findings suggest that the IGF-I present in nephrotic rat tubular fluid is bioactive and may contribute to the development of tubulo-interstitial fibrosis in chronic nephrotic glomerular diseases.     

Effect of telmisartan on the proteinuria and circadian blood pressure profile in chronic renal patients.

Telmisartan is a type 1 angiotensin II (AT(1)) receptor blocker, effective and safe in the treatment of arterial hypertension. However, data with respect to circadian blood pressure (BP) monitoring and urinary protein (uP) excretion are lacking in normotensive or mild hypertensive patients with chronic renal diseases. This study has evaluated the effects of 80 mg telmisartan, given as monotherapy, on 24 h BP levels and uP loss in 16 non-diabetic patients affected by proteinuric renal disease. These patients did not meet the recommended values of mean BP, i.e. < 98 mmHg, when proteinuria was 0.5-1.0 g/d and mean BP < 92 mmHg, when proteinuria was 1-3 g/d. Patients with diastolic BP > 114 mmHg, nephrotic syndrome or severe renal failure (creatinine clearance < 20 ml/min) were excluded. After 4.2 +/- 2.7 month therapy, ambulatory BP monitoring showed a significant decrease (P < 0.001) of 24 h BP levels: systolic 135 +/- 11 vs. 122 +/- 13 mmHg, diastolic 84.4 +/- 8.1 vs. 75.9 +/- 8.5 mmHg, mean 101 +/- 8 vs. 91 +/- 9 mmHg. The effect was quite evident during either day-time or night-time. Clinic BP levels also significantly decreased (P < 0.001), and five patients reached the target values. uP excretion lowered by 37% (median) from 1.60 +/- 0.90 to 1.06 +/- 0.63 g/24 h (P < 0.01). No change in creatinine clearance (53.3 +/- 31.1 vs. 51.7 +/- 30.9 ml/min) or serum potassium level (4.3 +/- 0.3 vs. 4.4 +/- 0.4 mEq/l) was observed. Our results show that 80 mg of telmisartan, taken once daily, is effective in reducing uP excretion and BP throughout the 24 h, in normotensive or mild hypertensive renal patients. Since evidence exists that adequate control of BP, including during night-time, and reduction of proteinuria play a crucial role in the protection of renal function, telmisartan can be usefully considered in the conservative treatment of renal patients.     

后腹腔镜肾囊肿去顶术治疗单纯性肾囊肿

目的 总结后腹腔镜肾囊肿去顶术治疗单纯性肾囊肿的临床经验,讨论人工后腹腔建立的方法.方法 1999年12月～2008年12月,78例后腹腔镜肾囊肿去顶术治疗单纯性肾囊肿.右侧肾囊肿47例,左侧肾囊肿31例.肾囊肿位于肾上极者21例,肾下极者47例,肾中段者10例.采用开放式和闭合式方法进行人工后腹腔建立.结果 75例手术成功,3例术中转开放性手术.手术时间50～100min,平均86.6min.53例开放式方法人工建立后腹腔,25例闭合式方法人工建立后腹腔.结论 后腹腔镜肾囊肿去顶术治疗单纯性肾囊肿疗效可靠,手术创伤小,术后恢复快.开放式人工后腹腔建立更易掌握、更加安全.     

个体化单纯性肾囊肿治疗方案探讨

目的探讨一种合适的单纯性肾囊肿治疗方案以提高肾囊肿的治愈率。方法回顾性分析383例单纯性肾囊肿患者的临床资料,分析患者全身情况、囊肿特点及囊肿大小等特点与成功治疗肾囊肿的相关性。结果接受经皮穿刺引流并反复注射无水乙醇的患者128例,接受经皮穿刺引流并反复注射无水乙醇联合生物蛋白胶治疗的患者157例,接受经腹膜后腹腔镜肾囊肿去顶减压术联合生物蛋白胶治疗的患者98例,其中有效率为98.7%,治愈率为93.2%。无其损伤脏器、感染性休克、化学性肾盂肾炎等严重并发症。结论并非所有单纯性肾囊肿患者实施同一化治疗方案,应该个体化对待。     

Stainable glomerular basement membrane polyanions and renal hemodynamics during hexadimethrine-induced proteinuria

To clarify the mechanism of hexadimethrine-induced proteinuria, we studied the changes in stainable glomerular basement membrane anions and renal hemodynamics during hexadimethrine (HDM) infusion. To determine whether glomerular anions were neutralized in vivo, animals infused with HDM received cationized ferritin intravenously, or their kidneys were perfused in situ with lysozyme. During its infusion, HDM bound heavily within the glomerular basement membrane, and binding of the cationic probes was virtually abolished. During recovery after HDM infusion, HDM deposits diminished and the binding of the cationic probes recovered to normal. The inverse correlation between HDM binding and binding of the cationic probes confirms that the glomerular binding of HDM is associated with neutralization or shielding of the glomerular basement membrane anions in vivo. Renal hemodynamic parameters and urinary protein excretion rate were measured before, during, and after infusion of HDM. Heavy proteinuria appeared during HDM infusion and persisted for 1 hour after its discontinuation. Although glomerular filtration rate, renal plasma flow, and urine flow rate decreased transiently at the onset of proteinuria, they returned to baseline levels before resolution of proteinuria. Filtration fraction never changed significantly. Thus, proteinuria cannot be attributed solely to renal hemodynamic factors. These results strengthen our hypothesis that HDM induces proteinuria as a consequence of its binding to and neutralization of glomerular basement membrane fixed anions.     

肾移植术后蛋白尿病因及转归的临床研究

目的:研究肾移植术后蛋白尿形成的主要原因及转归.方法:对105例肾移植术后蛋白尿患者进行回顾分析,研究其形成病因及其与转归的关系.结果:在105例肾移植尿蛋白患者中,由于排斥反应引起的占55.2％,由新发或复发性肾病引起的占34.3％,其余高血压、CNI肾毒性等原因的占10.5％.术后排斥反应和新发或复发性肾病导致肾移植术后蛋白尿总治愈率分别为93.10％和91.67％,两组比较差异无统计学意义(P＞0.05).与由高血压等其他原因所致蛋白尿患者比较,差异均有统计学意义(P＜0.05).结论:导致肾移植术后蛋白尿的主要原因是排斥反应和新发或复发性肾病,应根据移植肾穿刺后病理学诊断,及早进行相应临床治疗,以免造成不可逆性移植肾损伤.     

超高龄人群肾功能及尿蛋白对心血管事件发病的影响

目的：探讨肾小球滤过率估算值(eGFR)及尿蛋白水平对超高龄老年人发生心血管事件的影响。方法采用简化的 MDRD 公式进行估算,当 eGFR<60 ml·min-1·1.73 m-2时提示肾功能下降,将98例80岁及以上的查体老年人,分为肾功能下降组和肾功能正常组;又根据尿常规检测结果,将此98例分为尿蛋白阳性组和尿蛋白阴性组。随访心血管事件,比较不同组的心血管事件发生率,分析心血管事件发生的危险因素。结果①肾功能下降者(30/98)与尿蛋白阳性者(8/98)共占36.7%(36/98)。②随访时间平均(52.1±11.4)个月。至随访结束,存活42例,56例死亡者中发生心血管事件29例(29.6%)。③与肾功正常组比较,肾功能下降组患高血压、冠心病的比例升高(均 P <0.05),其空腹血糖、血尿酸、血尿素氮、白细胞总数升高(均 P <0.05),高密度脂蛋白胆固醇降低(P <0.05);与尿蛋白阴性组比较,尿蛋白阳性组中患高血压、糖尿病的比例高,eGFR 降低,血尿素氮 水 平 升 高(均 P <0.05)。④缺血性卒中、尿蛋白阳性、eGFR 水平是心血管事件发生的危险因素。⑤肾功能下降组患者的心血管事件发生率显著高于肾功能正常组36.7%(11/30)vs 26.5%(18/68),P <0.05;尿蛋白阳性组患者心血管事件发生率明显高于尿蛋白阴性组62.5%(5/8)vs 26.7%(24/90),P <0.01;缺血性卒中患者心血管事件发生率明显高于无缺血性卒中患者37.0%(10/27)vs 26.8%(19/71),P <0.05。结论超高龄老年人的 eGFR 下降、尿蛋白阳性以及有缺血性卒中史是心血管事件发生的危险因素。