99mTechnetium dimercaptosuccinic acid scintigraphy in the diagnosis of acute pyelonephritis in rats.

The use of 99mtechnetium dimercaptosuccinic acid (99mTc-DMSA) scintigraphy for the early diagnosis of pyelonephritis has been evaluated in a study performed on adolescent female Sprague-Dawley rats exposed to an ascending Escherichia coli infection. The rats were studied with DMSA scintigraphy either before and 5 days after the infection or 5 and 28 days after the infection. One group of rats received anti-microbial treatment during days 6-11. After the last DMSA scintigraphy the rats were sacrificed and the kidneys prepared for light microscopy study. Kidney morphology was normal and DMSA uptake was high and homogeneous in all control rats. The majority of the rats exposed to E. coli developed inflammatory changes, on light microscopy which extended to various degrees in the renal parenchyma. Five days after the infection the DMSA uptake was consistently reduced, if the inflammatory lesion on light microscopy involved more than 15% of the renal cortex. Twenty-eight days after infection the inflammatory changes were less extensive than at 5 days. The DMSA uptake had usually improved. At this time, however, areas of decreased DMSA uptake could be detected even if the light microscopy changes involved less than 15% of the parenchyma. Microscopical lesions were less frequent and less extensive in the treated than in the untreated rats. The complete return to normal of previously abnormal DMSA uptake was only observed in treated rats. In a few untreated rats cortical scars had formed by day 28. The scars appeared in areas with decreased DMSA uptake at 5 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of vesicoureteral reflux and urinary tract infection on renal growth in children with upper urinary tract duplication.

The growth of the renal parenchyma was examined in children with duplicated outflow systems, vesicoureteral reflux (VUR), urinary tract infection (UTI) and no sign of obstruction. Ten patients with reflux occurring only in the caudal system (group A) and 4 patients with reflux both to the caudal and the apical system (group B) were studied shortly after their first UTI (study 1) and then 1.5 to 9 years later (study 2). The frequency of UTI was relatively high during the follow-up period. At urography, renal length and renal area were normal in group A in studies 1 and 2. Parenchymal thickness of the apical pole (APT/L) did not differ from normal values in any of the studies. Parenchymal thickness of the caudal pole (CPT/L) was significantly smaller than normal in both studies. There was also a significant decrease in CPT/L between study 1 and 2. UTI during the first year of life was associated with a greater reduction in CPT/L. The determination of renal length and renal area in children with a duplicated ureter, VUR and UTI, does not identify subjects at risk of developing renal growth retardation while serial determinations of parenchymal thickness appear to be an appropriate method.

Ascending pyelonephritis in young rats retards kidney growth.

Several radiological studies have suggested that pyelonephritis in infancy and childhood may result in kidney growth retardation without renal scarring. In the present study, we induced ascending pyelonephritis in 20-day-old rats with intravesical infusion of E. coli. Four days after infusion, E. coli was cultured from all renal cortex. The rats were either left untreated (PNu) or were treated with trimethoprim-sulfa (PNt). The rats were investigated one month after infection and compared with an age-matched control group (C). Seventy-nine percent of the PNu rats had recovered spontaneously from infection. Body weight was the same in all groups. In PNu rats, kidney weight (KW), kidney area (KA) and glomerular filtration rate (GFR) were significantly decreased. KW, KA and GFR were similar in PNt and C rats. The numbers of filtering nephrons were not reduced by the infection. The total cortical DNA content (index of cell number) was significantly lower in PNu (5.30 +/- 0.32 mg) and PNt (6.62 +/- 0.44 mg) than in C rats (8.48 +/- 0.49 mg). The cortical DNA content was significantly lower in PNu than in PNt rats. The cortical protein/DNA ratio was significantly higher in PNu rats than in C rats. The protein/DNA ratio was similar in PNt and PNu rats. The increase in protein/DNA ratio was interpreted as a sign of cell hypertrophy. The inflammatory process as such did not increase the protein/DNA ratio. The kidneys were also examined for structural lesions. Signs of scarring, inflammation and cell necrosis were almost absent in all groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Distribution of renal scars and intrarenal reflux in children with a past history of urinary tract infection.

The distribution of renal scars in children with vesicoureteral reflux (VUR) and a past history of urinary tract infection was studied to see whether a correlation existed between renal scarring and intrarenal reflux. In 37 children with one or more scars in one or both kidneys, scarring was significantly more frequent in the polar areas than in the lateral area. In 7 children with intrarenal reflux (IRR), the distribution of IRR was almost identical with that of renal scarring. When children with marked VUR (grade IV-V) were analyzed separately, a uniform distribution of scars was found. It was concluded that fused papillae, which normally are most frequent in the polar area, are a prerequisite for the development of IRR/renal scars.

Influence of diuresis on the degree of vesicoureteral reflux. An experimental investigation in rats.

The influence of bladder filling volume (BV), bladder pressure (BP) and diuresis (V) on the occurrence of vesicoureteral reflux (VUR) in Sprague-Dawley rats, where spontaneous VUR is common, has been investigated. The BV and BP at which VUR occurred during constant low diuresis (group I), high inconstant diuresis (group II) and moderately high, constant diuresis (group III), was measured. The abdomen was opened for visual observation of the VUR. The bladder was catheterized with a double-lumen metal catheter for infusion of a Lissamine green saline solution and to enable recording of BP. VUR occurred at significantly lower BV in group II than in group I and at significantly lower BV and BP in group I than in group III.