Proximal renal tubular function was studied in 522 consecutive patients entered into the Medical Research Council's fourth myelomatosis trial. Assessment was made at presentation after a 48 h period of hydration but before administration of chemotherapy. The most common abnormalities in the urine other than light chain proteinuria were raised concentrations of the low molecular weight proteins alpha 1-microglobulin and alpha 1-acid glycoprotein. These were usually accompanied by increases in urinary beta-N-acetyl-D-glucosaminidase concentrations. The concentration of these substances in the urine directly correlated with urinary free light chain output. This tubular proteinuria was seen whether or not patients had impaired glomerular function, as assessed by a rise in serum creatinine concentration. Urinary concentrations of retinol binding protein, however, were generally increased only when serum creatinine concentrations were raised. This applied even when there were high concentrations of light chains, alpha 1-microglobulin, alpha 1-acid glycoprotein, and beta-N-acetyl-D-glucosaminidase in the urine. There is therefore a selective tubular proteinuria in myelomatosis which is seen in almost all patients with urinary light chain values greater than 1 u/l. This proteinuria is generally reversible, when light chains no longer appear in the urine. Patients whose serum creatinine was greater than 200 mumol/l, however, had increased urinary output of retinol binding protein in addition to increased excretion of alpha 1-microglobulin, alpha 1-acid glycoprotein, and beta-N-acetyl-D-glucosaminidase. Tubular proteinuria in many of these patients presenting in renal failure persisted even when light chain output was reduced after chemotherapy.
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机译:在参加医学研究理事会的第四次骨髓瘤病研究的连续522名患者中研究了近端肾小管功能。在水合作用48小时后但在化疗之前对患者进行评估。除轻链蛋白尿外,尿液中最常见的异常情况是低分子量蛋白质α1-微球蛋白和α1-酸性糖蛋白的浓度升高。这些通常伴随着尿中β-N-乙酰基-D-氨基葡萄糖苷酶浓度的增加。尿液中这些物质的浓度与尿中游离轻链输出量直接相关。通过血清肌酐浓度的升高来评估该肾小管蛋白尿症患者的肾小球功能是否受损。然而,通常仅当血清肌酐浓度升高时,尿中视黄醇结合蛋白的浓度才会增加。即使尿液中存在高浓度的轻链,α1-微球蛋白,α1-酸性糖蛋白和β-N-乙酰基-D-氨基葡萄糖苷酶,这种方法也适用。因此,在骨髓瘤病中存在选择性的肾小管蛋白尿,几乎在所有尿轻链值大于1 u / l的患者中都可见到。当尿中不再出现轻链时,这种蛋白尿通常是可逆的。然而,血清肌酐大于200摩尔/升的患者,尿中视黄醇结合蛋白的分泌量增加,此外α1-微球蛋白,α1-酸糖蛋白和β-N-乙酰基-D-氨基葡萄糖苷酶的排泄增加。即使化疗后轻链输出减少,许多这些表现为肾衰竭的患者中的肾小管蛋白尿仍持续存在。
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