[The intrarenal distribution of prostaglandin E2 and thromboxane A2 in the rat with unilateral ureteral obstruction or unilateral nephrectomy]

BACKGROUND

We evaluated the intrarenal distribution of prostaglandin E2 (PGE2) and thromboxane B2 (TxB2) on the rats that underwent unilateral ureteral obstruction (UUO), unilateral nephrectomy (UNX) or sham operation.

METHODS

Male Sprague-Dawley rats were divided into three groups; left ureteral obstruction (UUO), left nephrectomy (UNX) and sham-operation (Control). They were sacrificed at 1, 3, 6, 12, 24 hours and Day 2, Day 3, Day 5, Day 7 and Day 9 after surgery. Intrarenal distribution of eicosanoids were immunohistochemically detected on both kidneys of UUO rats, and on right kidneys of UNX and Control rats.

RESULTS

PGE2: In the obstructed kidneys, immunostained PGE2 increased in medullary interstitium at one hour to 6 hours, and in glomeruli and cortical interstitium at 6 hours. An increase of immunostained PGE2 was observed again in cortical interstitium at Day 3 to 5, and in medullary interstitium at Day 2 to 5. In the intact opposite kidneys, expression of immunostained PGE2 increased in glomeruli at Day 5 to 7, and in medullary interstitium at Day 3 to 5. In UNX, immunostained PGE2 increased in the medullary interstitium of the remnant kidneys at 3 hours and Day 3 to 7. On the other hand, an increase of immunostained PGE2 observed in glomeruli and cortical interstitium of these kidneys at Day 5 to 7. TxB2: In the obstructed kidneys, immunostained TxB2 increased in glomeruli and cortical interstitium at 6 hours, and in medullary interstitium at 3 to 12 hours. Predominant expression of TxB2 was observed in medullary interstitium at 3 hours compared to PGE2. We also observed an increase of immunostained TxB2 in cortical interstitium at Day 3 to 5, and in medullary interstitium at Day 2 to 5. In the intact opposite kidneys, immunostained TxB2 increased in medullary interstitium at 3 hours and Day 3. In the remnant kidneys of UNX, an increase of immunostained TxB2 was demonstrated in glomeruli at 6 hours and Day 7, and in medullary interstitium at 3 to 6 hours and Day 3 to 7.

CONCLUSION

In the obstructed kidneys, imbalance between PGE2 and TxA2 may contribute to the progression of renal injuries. The fact that expression patterns of these eicosanoids in the opposite kidneys of UUO different from that of the remnant kidneys of UNK, even though both were similarly associated with functional loss of contralateral kidneys, suggested that the opposite kidneys of UUO were affected by any additional factors different from that responsible for the remnant kidneys of UNK.

Unicalyceal kidney associated with ureteral anomalies

A unicalyceal kidney is a very rare anomaly of the urinary system. We report 4 cases of unicalyceal kidneys in infants. All cases were associated with ureteral anomalies: megaureter on the involved side, and/or ectopic ureter with vesicoureteral reflux or renal agenesis on the contralateral side. In order to preserve renal function we recommend surgical treatment for patients with unicalyceal kidney when they have ureteral anomalies.

[Renal function in children with reflux nephropathy followed up more than 10 years after disappearance of vesicoureteral reflux: usefulness of alpha 1-microglobulin as a marker to predict the prognosis of these children]

BACKGROUND

Although reflux nephropathy (RN) is one of the most important causes of renal failure in adolescence and young adulthood, we have no appropriate markers to know the future course of children with RN. In order to find out useful marker to predict the prognosis of these children, we analyzed the result of over ten years follow-up of children with RN.

METHODS

We evaluated renal function in 25 patients (aged between 11 years and 23 years, 14 males and 11 females) with RN using urinary alpha 1-microglobulin (alpha 1 m), urinary albumin and 99mTc-dimercaptosuccinic acid (DMSA) renal scan. All patients were followed up more than 10 years after disappearance of vesicoureteral reflux.

RESULTS

Of 25 patients, 13 showed high levels of urinary alpha 1 m (> 4.4 mg/gCr = upper normal limit) during follow-up period. Among them, renal dysfunction developed in 9 on DMSA renal scan and/or serum creatinin (Cr) level. Before puberty, all patients, even children with renal dysfunction (serum Cr > 1.0 mg/dl), remained in normal or slight high urinary albumin levels. Five cases, showed high levels of urinary alpha 1 m before puberty, demonstrated a remarkable increase of urinary albumin levels after puberty.

CONCLUSION

From these results, it was suggested that urinary levels of alpha 1 m could be utilized as a marker to predict the prognosis of children with RN.

[Effect of hydronephrosis on the contralateral blood flow and glomerular volume]

We designed a following experiment to appraise the effect of unilateral hydronephrosis on the contralateral kidney using weanling rats whose kidneys were in a growing stage. Rats were divided into 4 groups. Complete unilateral (left) ureteral obstruction (CUUO) was made on the experiment rats, and these went through the following procedures on the day 3 after CUUO; 1) Group R: CUUO released, 2) Group N: left nephrectomy performed, 3) Group S: CUUO continued. Sham-operations were performed on the days 0 and 3 to the controls. Renal cortical blood flow and glomerular volume of the contralateral (right) kidneys were determined on the days 5, 7, 9, 14 and 21. Blood flow to the renal cortex per unit volume (ml/min/100 cm3; measured with Laser blood perfusion monitor) in the contralateral kidneys increased gradually in the all groups, but statistical significance was not confirmed in the observed period between any groups. Increases in total renal blood flow (wet kidney weight times renal cortical blood flow per unit volume; g x ml/min/100 cm3) were proportional to the measured wet kidney weight in the all groups. Notably in the group N, a significant increase was noted compared to the group R and the controls. Glomerular volume (GV) of the contralateral kidneys did not show significant changes on the day 3 compared to the controls. GV significantly grew up during the day 5 to the day 14 (2 to 11 days after the relief of CUUO) in the group R and then it settled to the level of the controls on the day 21.(ABSTRACT TRUNCATED AT 250 WORDS)

[The effect of unilateral ureteral obstruction on the contralateral renal growth in weanling rats]

The effect of unilateral hydronephrosis on the growth of contralateral kidney were evaluated with weanling rats of which kidneys were in growing stage (body weighted between 80 g and 90 g). These rats underwent complete unilateral ureteral obstruction (CUUO) on day 0. They were divided into 3 groups and went through second operations on day 3 (CUUO-3) as follows; a) CUUO released, b) nephrectomy performed and c) CUUO continued. Sham-operation was performed on day 0 and on day 3 to the controls. Wet weights and bromodeoxy-uridine (BrdU) labeling index (L.I.) (index for cell proliferation in the uriniferous tubules) of the contralateral kidneys were measured for the evaluation. The wet weights were significantly higher in all the groups than that of the controls throughout the observation period on and after the day 3. The group that underwent nephrectomy demonstrated a sharp rise in L.I. after the day 7. In the group that was continued in CUUO, the L.I. started to rise later than its rise in nephrectomised group but the index caught up at the time when the blood flow completely disappeared in the kidneys of the ligated side. L.I. in the group of which CUUO was released became significantly higher than that of controls on the day 7 and remained its significance until the day 21 in spite of resolution of the hydronephrosis. To reveal the effect of length of obstructed term, the same trial was carried out that rats endured in CUUO for 5 days (CUUO-5) till the second operation. This turned out lower L.I. in the CUUO-5 than the CUUO-3. These results suggest that the presence of hydronephrosis made by CUUO suppress the growth (cell proliferation) of contralateral kidney and also duration of obstruction can be critical on the renal growth that shorter obstructed period turns out preferable for cell proliferation after relief of CUUO.

[Renal function of contralateral kidney after total or partial removal of kidney with ectopic ureter]

The effects of partial or total removal of the kidney with ectopic ureter on the contralateral kidney were evaluated using DMSA renal uptake rate on 8 patients. After partial nephrectomy on 6 cases, the affected residual kidneys showed significant decrease in DMSA renal uptake rate in 2 cases in which the extirpated kidneys had normal renal tissue in part but did not show significant change in DMSA uptake rate in 4 cases in which the extirpated kidneys were dominated mainly with dysplasia. Post-operative increase in DMSA uptake rate of the contralateral kidneys were significant in 3 of 4 patients who had the operation before they became 2 years old. In 2 of these 3 cases, pre-operative scintigram showed extremely low rate of DMSA renal uptake. Four cases aged 2 years old and over did not show post-operative increase in the uptake rate. As we have previously reported on the cases with hydronephrosis, these results suggest that 1) existence of obstruction caused by ectopic ureter inhibit the development of the contralateral kidney and 2) the growth of the kidney can resume the release of that obstruction, if the release is made while the kidneys are still in developing stage.

[Studies on reflux nephropathy--renal tubular and glomerular damage evaluated by various urinary indices]

Measurements were performed on beta 2-microglobulin (beta 2-MG), alpha 1-microglobulin (alpha 1-MG), N-acetyl-beta-D-glucosaminidase (NAG) as indices of renal tubular damage and microalbumin as an index of renal glomerular damage in 204 cases with primary vesicoureteral reflux (VUR). Investigations were made on the relationship between each index and extent of renal cortical damage from the findings of 99mTc-dimercapto-succinic acid (DMSA) renoscintigraphy, and also on the changes of each index before and after antireflux operation. At the first examination, high values of urinary beta 2-MG, alpha 1-MG, NAG and albumin were noted in 36%, 40%, 50% and 34% of cases with VUR respectively. Almost all the cases with high indices values before the operation showed improvement in those values accompanied with disappearance of VUR after the operation. These findings suggest that renal tubular and glomerular damage were induced by the sterile reflux itself. High values of urinary indices were confirmed in 16% (beta 2-MG), 40% (alpha 1-MG), 27% (NAG) and 32% (albumin) cases after a lapse of 2 years or longer since antireflux operation or spontaneous disappearance of VUR. In some of these cases indices values showed some improvement but have not returned to normal levels, and in other cases indices were within normal limits preoperatively but turned out to be high levels during the observation period even after the disappearance of VUR. Most of these cases were accompanied with severe cortical damage of unilateral or bilateral kidneys on DMSA renoscintigraphy. Based on these findings, we suggest that overload to residual nephron, caused by reduced mass of functional nephron, is playing an important role on raising the values of various urinary indices.

[Effect of unilateral hydronephrosis upon contralateral renal growth]

To evaluate the effect of hydronephrosis on the growth of contralateral normal kidney, following experiment was designed and performed.

EXPERIMENT

Three to four weeks old S-D rats weighing 80-90 g were used. The kidney development of these rats is considered to be roughly equivalent to that of a one year old child. Those rats were divided into three groups: (1) left nephrectomy (group N), (2) left ureteral ligation (group H), and (3) sham operation (group S). Bromodeoxy uridine (BrdU) was administered intraperitoneally on the 1st, 3rd, 5th, 7th and 14th days after operations. One hour after injection of BrdU, right kidneys were removed and wet weight and labelling index (LI) of BrdU were calculated. Compensatory renal growth of right kidneys was observed in both group H and group N on and after 1st or 3rd day. In group N, the growth was accompanied by cellular proliferation, while in group H, hypertrophy was the major finding for up to 5th day. From 7th day on, when significant disorders became histologically evident in the left hydronephrotic kidneys, cell proliferation was also observed in the group H. The above results indicate that compensatory renal growth occurred in the contralateral normal kidney after unilateral ureteral ligation. Although proliferation of right renal tubular cells were recognized when significant tubular and interstitial damage of the left hydronephrotic kidneys were observed, hypertrophy was a major finding in an early stage. We suggest that these results were attributed to (1) reduction of nephron triggered to proliferate tubular cells and (2) the existence of hydronephrotic kidney inhibited tubular cell proliferation.

[Evaluation of renal function and prediction of renal functional recovery in children with unilateral hydronephrosis using renal pelvic urine]

In 29 children with unilateral hydronephrosis who underwent surgery at the age from 2 months to 15 years (27 patients with ureteropelvic junction stenosis and 2 with obstructive megaureter), beta 2-microglobulin (beta 2-MG), alpha 1-microglobulin (alpha 1-MG), N-acetyl-beta-D-glucosaminidase (NAG) and albumin were determined in renal pelvic urine from the hydronephrotic kidney to evaluate renal dysfunction accompanying urinary tract obstruction. Moreover, it was also examined whether it is possible to predict functional recovery of the hydronephrotic kidney on the basis of relation between these indices and pre- and postoperative changes in renal dimercaptosuccinic acid (DMSA) uptake rate. The values of beta 2-MG, alpha 1-MG, NAG and albumin in urine from the renal pelvis were high in 48%, 50%, 75% and 83% of the patients, respectively. Among the patients of one year and up, those with low preoperative DMSA uptake rate tended to have high values of beta 2-MG, alpha 1-MG and NAG. On the contrary, albumin level was high in 78% of patients who had good preoperative DMSA uptake rate. With respect to the relation between pre- and postoperative changes in DMSA uptake rate and each index, beta 2-MG and alpha 1-MG were high in 73% and 62% of patients who exhibited a marked increase in postoperative DMSA uptake rate. In patients without a remarkable change in DMSA uptake rate before and after surgery, on the other hand, the values of these were high only in 25% and 36%.(ABSTRACT TRUNCATED AT 250 WORDS)

[Renal function in children with solitary kidney]

Renal function of eighteen children with solitary kidney (14 congenital and 4 acquired) was assessed using DMSA renal uptake rate and urinary excretion of alpha 1-MG, beta 2-MG, NAG and microalbumin. Seven of the cases were associated with vesicoureteral reflux (VUR) and two with congenital hydronephrosis. These anomalies have been already treated surgically before entering this study. DMSA renal uptake rate of 8 children was the same as that of the controls (51.8 +/- 3.7%; mean +/- SD). However, the uptake rate of 10 cases were more than 2SD below the mean of the controls. In five of them, including two children with no other urinary tract anomaly, the uptake rate was less than 70% of the mean of the controls. Half of 14 children evaluated with alpha 1-MG showed high values. In 6 of these 7 cases, DMSA renal uptake rate was more than 2SD below the mean of the controls. Urinary microalbumin was not correlated with urinary alpha 1-MG or DMSA renal uptake rate. Three of 4 children with high values of urinary microalbumin were more than 10 years old. Nine of 12 children evaluated with all the indices mentioned above showed high values of urinary alpha 1-MG and/or microalbumin. Low DMSA renal uptake rate was revealed in 7 out of these 9 children including two cases without urinary tract anomaly. These results indicate that, in the cases with solitary kidney even though no other urinary tract anomaly is recognized, renal overload may have already developed in early life.

[Urinary incontinence in children with primary vesicoureteral reflux--urinary incontinence and function of refluxing kidney]

The interrelation among urinary incontinence (nocturnal enuresis, urge incontinence), history of urinary tract infection and renal function was investigated in 153 children with primary vesicoureteral reflux who were more than three years old. Of them, 98 children (64%) had the chief complaint of urinary tract infection (UTI) and 43 children (28%), urinary incontinence. Of the children whose chief complaint was UTI, 44 (45%) had incontinence. Thus, 87 children (57%) with VUR had urinary incontinence. Almost all the children who had urinary incontinence and no previous UTI had good renal function. Renal dysfunction was found in children with previous UTI history. These studies on children with primary VUR more than three years old indicate that, although urinary incontinence could be a factor for recurrence of UTI and a probable cause of worsening of renal function, there is no direct correlation between urinary incontinence and renal dysfunction accompanied by VUR.

[Evaluation of renal function in children with primary VUR up to two years old]

The function of 99 refluxing kidneys of 61 children up to two years old at the time of diagnosis was evaluated by 99mTc-DMSA renoscintigraphy, urinary beta 2-microglobulin (beta 2-MG), alpha 1-microglobulin (alpha 1-MG) and N-acetyl-beta-D-glucosamidase (NAG). High grade reflex (grade IV, V) was found in 45% of the cases. 76%, 51% and 92% of the cases showed abnormally high value of urinary beta 2-MG, alpha 1-MG and NAG, respectively. These results indicate that they have already had tubular dysfunction at the time of diagnosis. DMSA renoscintigraphy of 82 refluxing kidneys of 49 children was performed. Of these, 48% had renal scar and 28% had serious renal dysfunction [DMSA uptake rate less than 18%]. 10-20% of low grade VUR had less than 18% DMSA uptake rate. Two patterns were noticed in the group in which urinary beta 2-MG ranged 0.33-1.0. One was characterized by good bilateral renal function with slight tubular damage and the other serious renal dysfunction with fixed tubular damage. No remarkable recovery of the renal function was noticed after antireflux operation in the second pattern cases. In many cases, in which urinary beta 2-MG was more than 1.0, improvement of DMSA uptake rate was noticed after antireflux operation.

[Evaluation of renal scarring in children with primary VUR by 99mTc-DMSA renoscintigraphy]

Renal scarring in 271 kidneys of 172 children with primary vesicoureteral reflux (VUR) was evaluated by 99mTc-DMSA renoscintigraphy. 58% of refluxing kidneys were with renal scar by the initial DMSA renoscintigraphy. Only 52% of these kidneys showed good correlation between the findings on IVP and DMSA renoscintigram. Of the 144 refluxing kidneys with normal IVP, 41% had renal scarring on DMSA renoscintigram. DMSA renoscintigram revealed widespread renal scarring in 28% of kidneys with only calyceal clubbing and in 60% of those with segmental cortical thinning on IVP. It is realized that IVP was an in-sensitive method to evaluate renal scarring of refluxing kidneys and such kidneys with segmental renal scar on IVP accompanies more widespread scar on DMSA renoscintigram. These cases were allocated to 2 age groups, younger than 3 years and older than 4 years. In the former group less than 10% of kidneys with low grade VUR and about 40% with high grade UVR had widespread renal scarring. On the contrary, in the latter group severe renal scar was recognized in more than 20% of kidneys with low grade VUR and in about 60% with high grade UVR.

[Enoxacin concentration in human prostatic tissue after 3-day administration]

The penetration of enoxacin into prostatic tissue was examined Thirty-five patients with benign prostatic hypertrophy entered the study. Enoxacin was administered orally in a dose of 200 mg three times daily for 3 days preoperatively. Blood samples were taken simultaneously at the time of tissue sampling. The patients were divided into groups 1 and 2. In group 1, tissue sampling was done after about 17 hours of final administration of the drug. The mean concentration of enoxacin in prostatic tissue was 1.87 +/- 1.23 micrograms/g and 1.05 +/- 0.458 micrograms/ml in serum. In group 2, sampling was done after 5.5 hours of final administration. The mean concentration of enoxacin in prostatic tissue was 2.51 +/- 0.725 micrograms/g and 1.78 +/- 0.586 micrograms/ml in serum.