Collection of urine sample for examination of proteinuria has been described elsewhere. [17]Briefly, urine specimens were taken during a 4-h examination. p 2 -microglobulin was measured in aliquots of the hour-one urine sample while total protein and albumin were measured in the hour-four urine sample. Kidney sizes were measured in millimeters using ultrasound investigations of both kidneys (left and right). The longest dimension and the smallest thickness of kidney parenchyma were determined. Also, location, size and morphology (cysts, stones and tumors) of the kidneys were obtained. All images were saved electronically for future reference. Serum creatinine was collected and was used to calculate creatinine clearance (CCR) using the Cockcroft and Gault formula (1976). [31]