No abstract

Partial obstruction of the left ureter was created in two-day-old rats and its effects on kidney function were studied with 99mTc-DMSA and 99mTc-DTPA after one, two, three and six weeks, and after one year. Kidneys from animals sacrificed at the age of six weeks or one year were also examined histologically. The obstructed renal pelvis was enlarged by about 35 times and there was a delayed excretion of 99mTc-DTPA during forced diuresis, indicating significant, chronic obstruction. The renal DMSA-uptake ratio (left kidney/(left and right kidney] was reduced to about 40% from the first week of obstruction. The parenchymal weight ratio (expressed as above) was reduced to about 45% after both six weeks and one year. The glomerular filtration rate, examined during forced diuresis and calculated on the basis of uptake capacity, was lowered to 42% after six weeks but was not significantly reduced after one year of obstruction. The incidence figures for medullary hemorrhage or accumulation of iron pigment, and chronic inflammatory changes in the cortex were somewhat higher after one year of obstruction than after 6 weeks, but the lesions were patchy in both groups. We conclude that partial unilateral ureteric obstruction, created in the neonatal period, leads to a slight but permanent functional disturbance and parenchymal weight reduction without prominent structural parenchymal damage.

Partial obstruction of the ureter was created in newborn rats, and its effects were studied after 1, 2, 3, 6 and 9 weeks--that is, until adult age. Within 1 week, a considerable hydronephrosis had appeared. Within 2 weeks, parenchymal weight was found slightly reduced (8 per cent) on the obstructed side, and, within 3 weeks, equivalently increased on the contralateral, intact side. After these points in time, there was no further deterioration. Histological examination revealed marked deformation of the papilla and minor foci of degeneration and inflammation within 1 to 2 weeks which tended to become chronic in type after 3 to 9 weeks. Arterial hypertension was not noted. Thus, the effects of partial ureteric obstruction on the renal parenchyma are 1) discrete, 2) not in proportion to the degree of hydronephrosis, 3) fully compensated by contralateral hypertrophy and 4), after reaching an early maximum, not increasing with time.

Partial obstruction of the left ureter was created in newborn rats. The obstruction was either permanent or was released after two or seven days. The effects were studied at the age of six weeks. The permanently obstructed kidneys characteristically exhibited considerable enlargement (X 18) of pelvic volume and prominent deformation of the papilla, frequently associated with moderate widening of collecting ducts and convoluted tubuli, and focal inflammatory and degenerative lesions. The weight difference between the hydronephrotic and the contralateral, intact kidney was significantly higher than in a sham operated group, although the combined kidney weight was unchanged, indicating a reduction on the obstructed side and a compensatory contralateral hypertrophy. In the group released after seven days, the pelvic volume had returned to normal; nevertheless the parenchymal weight pattern and the histological lesions were similar to those found in animals obstructed for six weeks. In the group released after two days, the pelvic volume had normalized, and the histological changes were less prominent than in animals obstructed for seven days or six weeks. Yet there was a significant difference in parenchymal weight between the hydronephrotic and the contralateral kidney, almost entirely caused by hypertrophy on the nonobstructed side. Thus, the ureteric obstruction must be released very early to avoid parenchymal weight reduction and curb the tissue lesions. On the other hand, the resulting parenchymal damage is moderate and does not seem to progress with time.

OK-432 treatment resulted in a successful outcome in 70% of patients with lymphatic malformations. The long-term outcome was comparable to the short-term outcome.