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The purpose of the present study was to examine renal functional changes caused by chronic blockade of nitric oxide (NO) synthesis in young rats. Two types of NO synthase inhibitor were used: NG-nitro-L-arginine methyl ester (L-NAME) as a non-selective inhibitor and aminoguanidine (AG) as a selective inhibitor of the inducible isoform. Oral administration of L-NAME (20-80 mg/dL of drinking water), not AG (400 mg/dL), for 4 weeks induced systemic hypertension in the treated rats. Both inhibitors caused a significant reduction in urinary excretion of NO2-/NO3-. Rats treated with L-NAME developed proteinuria and tubular enzymuria (high excretion of N-acetyl-beta-D-glucosaminidase) in a dose-dependent fashion, with normal serum levels of creatinine, albumin and cholesterol. Chronic AG administration did not alter the urinary levels of protein and N-acetyl-beta-D-glucosaminidase or serum laboratory values. Overall, these observations highlight the importance of the continuous generation of NO by the constitutive isoform in the control of vascular tone and the maintenance of renal glomerular and tubular function. Oral administration of L-NAME may serve as a model of chronic NO-deficient hypertension with renal injury in young rats.

Several less harmful methods than voiding cysto-urethrography for detecting significant ureteric reflux have been proposed. The present prospective study investigated whether ultrasonography was effective in identifying ureteric reflux in infants with their first febrile urinary infection. The subjects were 27 infants (24 boys and 3 girls) aged from 0 to 8 months. The urinary tract was scanned when the bladder was full, and before and during induced voiding. Infants with abnormal ultrasound findings underwent voiding cysto-urethrography. The other infants were followed and those who had a recurrence of urinary infection underwent voiding cystography. Ten children underwent cysto-urethrography, with eight refluxing ureters identified in six boys. Ultrasound revealed transient dilatation of the renal pelvis on voiding in five kidneys, transient dilatation of distal ureters in 12 and hydro-ureteronephrosis in two. Each of the five kidneys with pelvic dilatation on voiding was associated with ureteric reflux grades III or IV. Of the 17 children who did not undergo cysto-urethrography, only one had recurrence of urinary infection and was diagnosed with ureteric reflux. This girl was one of the three babies who were not scanned during voiding. More than half of the infants with febrile urinary infection were excluded from invasive examination without having recurrence of urinary infection. Thus, ultrasound scanning during voiding was effective for screening infants with their first urinary infection to detect significant ureteric reflux.

Dilatation of the renal pelvis has been observed as an ultrasonographic finding of ureteral reflux as well as hydronephrosis. However, little information is available on the prevalence of renal pelvis at dilatation in neonates. We measured the inner pelvis dimension of the kidneys in 511 apparently healthy neonates (279 boys and 232 girls) using an ultrasound scanner to determine the prevalence of renal pelvis dilatation. Ninety per cent of the neonates had an inner dimension of both renal pelvises below 5 mm. The prevalence of left renal pelvis dilatation of 5 mm or more was significantly higher in the boys than in the girls, 25 (9%) compared to 5 (2%). In contrast, no significant difference was found in the prevalence of right renal pelvis dilatation between the sexes. In the boys, the prevalence of renal pelvis dilatation of 6 mm or more was significantly higher on the left side than on the right. Moreover, the left renal pelvis dilatation of the male neonates had a tendency to persist at 1 month of age. These findings suggest that the left renal pelvis of the baby boy may be predisposed to dilatation.

The following is a case of a family with a pair of identical twins and a family history of insulin-dependent diabetes mellitus (IDDM). A 2 year old identical twin was first admitted to our hospital and diagnosed as IDDM based on diabetic ketoacidosis. His father has been treated with insulin since the diagnosis of IDDM at the age of 17. All family members had the HLA-DR4 and DQA1*0301 alleles, which are strongly associated with IDDM. The DR-DQ haplotypes of the father and both twins were DR4-DQW8 (DQB1*0302), which increases susceptibility to IDDM. Islet cell antibodies were positive only in the index twin at the time of diagnosis. The co-twin was considered to have beta-cell dysfunction based on the result of an intravenous glucose tolerance test.