We have developed a sensitive EIA which allows direct determination of the concentrations of urinary type IV collagen (uCL-IV). Specimens of both spot urine and first urine in the morning were obtained from 35 normal subjects (24males, 11 females) aged 21 to 54 (32.0±9.4, mean±SD) years old.Urinary concentrations of CL-IV were 4, 02±1, 86μg/g Crin the spot urine, and 2.16±0.79μg/gCr in the first urine. The first urine is not influenced by physical activity during the day, and the results suggest that the first urine is preferable for the determination of uCL-IV. The reference value in the first urine is below 3.74μg/gCr in normal subjects. Urinary CL-IV excretion was significantly increased in diabetic subjects with nephropathy: 5.00±3.68μg/gCr in 26 diabetics with incipient nephropathy, and 24.1±17.7μg/gCr in 22 diabetics with overt nephopathy. CL-IV is a structural protein unique to the basement membrane (BM). Pathological findings in glomeruli of the diabetic kidney are thickening of the BM and expansion of the mesangial area. Augmented expression of CL-IV has also been reported. The evaluation of uCL-IV by direct assay provides information on the activity of structurally altered glomerular processes, and will thus contribute to better management of diabetic nephropathy.
The effect of the additional administration of α-glucosidase inhibitor on glycemic regulation in NIDDM patients treated with gliclazide was investigated. Sixteen outpatients (8 males and 8 females) with NIDDM who showed good to fair glycemic control under gliclazide administration were enrolled into the present study. At the time of α-glucosidase inhibitor administration (acarbose or voglibose), the daily doses of gliclazide were halved. Thereafter, the doses of gliclazide were adjusted to achieve better glycernic control, according to blood glucose and, glycated albumin concentrations. After 12-weeks caf α-glucosidase inhibitor administration, the daily doses of gliclazide required for effective glycemic control diminished from 64±35 to 48±31 mg/day. Levels of glycated hemoglobin and glycated albumin decreased significantly from 7.1±0.3 to 6.8±0.2%, and from 18.9±1.1 to 17.2±1.0%, respectively, Plasma glucose concentrations at 2-hr after breakfast also decreased significantly from 166±28 ta 123±27 mg/dl. Hypoglycemic episodes did not oceur throughout the iiivestigatiori period. These observations indicate that the present therapeutic approach to treatmeiit of postprandial hyperglycemia in patients vvith NIDDM is efficient and safe, suggestillg that the regimell leads to prevention af the exhaustion of pancreatic beta cell function.