1986 Volume 41 Issue 2 Pages 539-549
Five urinary proteins were analysed among the 121 inhabitants, 63 males and 58 females aged 2-86 years, of a cadmium polluted area in the Jinzu river basin. The relation between the progression of renal dysfunction and the patterns of protein excretion in urine was studied.
1) The urinary excretion of low molecular weight (LMW) proteins larger than β2-microglobulin (β2-m), such as retinol binding protein and α1-microglobulin, increased in proportion to urinary β2-m concentration. When the concentrations of β2-m in urine were over 10mg/g.cr, the excretion of intermediate molecular weight (IMW) proteins, such as albumin (Alb) and Gc-globulin, in urine increased.
2) According to the β2-m and Alb concentrations, the urinary protein excretion patterns were classified. Among the inhabitants of the cadmium polluted area, normal type: β2-m under 0.59mg/g.cr and Alb under 40mg/g.cr was 57.9%, LMW protein dominant type: β2-m over 0.59mg/g.cr and Alb under 40mg/g.cr was 26.4%, LMW and IMW protein mixed type: β2-m over 0.59mg/g.cr and Alb over 40mg/g.cr was 15.7% and IMW protein dominant type: β2-m under 0.59mg/g.cr and Alb over 40mg/g.cr was none. The glomerular dysfunction was found by analysis of creatinine clearance and serum creatinine concentrations among inhabitants showing LMW and IMW protein mixed type.
3) As age class became higher or residence time in the polluted area became longer, the rates of cases showing LMW protein dominant type or LMW and IMW protein mixed type increased in both sexes in the polluted area. The rates of the cases showing LMW and IMW protein mixed type were higher among females than males. For reference, 47 out of 49 inhabitants of a non polluted area showed normal type and all 34 itai-itai disease patients showed LMW and IMW protein mixed type.
The classification mentioned above would be useful and convenient for differentiation of the stages of renal dysfunction caused by cadmium.
