title: Eight-month longitudinal study of urinary excretion of albumin and tubular proteins in diabetic subjects.
abstract: To evaluate the importance of tubular proteinuria in diabetic nephropathy, we studied the serial changes of micro-albuminuria, microproteinuria and protein patterns by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) in 38 diabetic patients over 8 months. There was a significant correlation between the amount of micro-albuminuria measured by radio-immunoassay and the amount of microproteinuria quantitated by the Coomassie brilliant blue dye binding method (r = 0.976; p less than 0.0001). Micro-albuminuria of 50 mg/day was equivalent to microproteinuria of 190 mg/day. Among the 38 diabetic patients, 26 had micro-albuminuria above 50 mg/day, while 12 had micro-albuminuria below this level. There was a significant correlation between the amount of microproteinuria and haemoglobin A1, showing that the quantity of microproteinuria was affected by metabolic control. Diabetic patients with micro-albuminuria of above 50 mg/day have a significantly higher diastolic blood pressure than those below this level. Among the diabetic patients with micro-albuminuria of less than 50 mg/day, the amount of micro-albuminuria and microproteinuria remained constant, whereas progressive increases in micro-albuminuria and microproteinuria were observed among the 12 diabetic subjects with micro-albuminuria above 50 mg/day. These support the prognostic importance of this quantity of micro-albuminuria. The protein patterns as revealed by SDS-PAGE with Coomassie blue staining show a significant loss of low-molecular-weight proteins in 7 patients, which may therefore suggest tubular damage. The loss of tubular proteins persisted over a period of 8 months in all 7 subjects, and the amount gradually increased over this period.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medicine, University of Hong Kong.
authors.forename: K K
authors.initials: KK
authors.lastname: Pun
authors.forename: P
authors.initials: P
authors.lastname: Ho
authors.forename: P
authors.initials: P
authors.lastname: Lau
authors.forename: F H
authors.initials: FH
authors.lastname: Wong
mesh_terms: D000328:Adult; D000419:Albuminuria / Q000453:epidemiology*; D003928:Diabetic Nephropathies / Q000453:epidemiology / Q000652:urine*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011507:Proteinuria / Q000453:epidemiology*; D011863:Radioimmunoassay; D012394:Rosaniline Dyes; D013194:Staining and Labeling; D013997:Time Factors
chemical_list: D012394:Rosaniline Dyes; C004692:coomassie Brilliant Blue