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PubMed1998

Renal hemodynamic changes after complete and partial unilateral ureteral obstruction in the fetal lamb.

PURPOSE: Complete and partial ureteral obstruction decreases ipsilateral renal blood flow in neonatal and adult animals. However, the effects of obstruction that develops during gestation may be different from those in neonatal or adult animals. We determine whether complete or partial ureteral obstruction decreases ipsilateral renal blood flow in fetal sheep. MATERIALS AND METHODS: We positioned an ultrasonic flow transducer around both renal arteries in 21 fetal sheep at 123 to 125 days of gestation. Unilateral ureteral obstruction was created in 16 fetuses, including complete and partial obstruction in 7 and 9, respectively. There were 5 controls. Renal blood flow and arterial blood pressure were measured daily for a minimum of 7 days. RESULTS: All obstructed kidneys had hydronephrosis, partially obstructed kidneys had less obstruction and contralateral kidneys had none. Renal weight was similar in obstructed and contralateral kidneys in the sham operated, partial and complete obstruction groups. After partial ureteral obstruction renal blood flow in obstructed and contralateral kidneys was increased compared to that in sham operated kidneys up to 11 days after obstruction was created. After complete ureteral obstruction the blood flow in obstructed kidneys was significantly lower than in the unobstructed counterparts but it remained 124% of initial renal blood flow at 10 days. Elevated ureteral pressure was maintained in obstructed kidneys throughout the study period. CONCLUSIONS: In our experiment partial ureteral obstruction in the fetus did not decrease renal blood flow to the ipsilateral kidney even after 7 days. Complete obstruction decreased blood flow in the affected kidney but not to same magnitude as that in previous adult animal studies. Our findings suggest that during gestation renal blood flow is maintained in the presence of obstruction.

Animals↗
PubMed2003

Antegrade pyelography for suspected ureteral obstruction in cats: 11 cases (1995-2001).

OBJECTIVE: To determine sensitivity and specificity of radiography, ultrasonography, and antegrade pyelography for detection of ureteral obstructions in cats. DESIGN: Retrospective study. ANIMALS: 11 cats. PROCEDURE: Medical records of cats that had radiography, ultrasonography, and antegrade pyelography performed for suspected ureteral obstructions were examined. Ultrasound-guided pyelocentesis and fluoroscopic-assisted antegrade pyelography were performed on 18 kidneys in 11 cats. Obstructive ureteral lesions were confirmed in all cats by surgical or necropsy examination. Sensitivity and specificity of survey radiography, ultrasonography, and antegrade pyelography for identification of ureteral obstructions were calculated. Surgical or necropsy findings were used as the standard for comparison. RESULTS: All cats were azotemic. Mean +/- SD serum creatinine and BUN concentrations were 10.2 +/- 6.1 and 149 +/- 82 mg/dL, respectively. Fifteen of 18 ureters were found to be obstructed at surgery or necropsy. Sensitivity and specificity were 60 and 100% for radiography and 100 and 33% for ultrasonography, respectively, in identification of ureteral obstructions. Leakage of contrast material developed in 8 of 18 kidneys during antegrade pyelography and prevented diagnostic interpretation in 5 of 18 studies. For the 13 diagnostic studies, specificity and sensitivity were 100% by use of the antegrade pyelography technique. Correct identification of the anatomic location of the ureteral obstruction was obtained in 100% of diagnostic antegrade pyelography studies and in 60% of radiography or ultrasonography studies. CONCLUSIONS AND CLINICAL RELEVANCE: Antegrade pyelography can be a useful alternative in the diagnosis and localization of ureteral obstructions in azotemic cats, although leakage of contrast material may prevent interpretation of the study.

Animals↗
PubMed1990

Hydronephrotic atrophy after stable mild or severe partial ureteral obstruction: natural history and recovery after relief of obstruction.

After stable mild or severe partial unilateral ureteral obstruction in rats, the ratio of renal dry weight to whole body weight changes in two phases. In a "destructive phase" of two to six weeks, slight weight reduction occurs in the kidneys with mild obstruction and pronounced weight reduction occurs in those with severe obstruction. Then, in a "steady-state phase", there is no further weight reduction in kidneys with either mild or severe obstruction. Relief of ureteral obstruction during the steady-state phase does not result in an increase in renal dry weight. We conclude that the development of hydronephrotic atrophy after stable mild or severe partial unilateral ureteral obstruction can not be influenced by relief of obstruction in the steady-state phase.

Animals↗
PubMed1993

The significance of ureteral obstruction in invasive transitional cell carcinoma of the urinary bladder.

Ureteral obstruction is a frequent complication of transitional cell carcinoma (TCC), known as a poor prognostic sign and indicative of advanced disease. We investigated retrospectively the medical records of 122 consecutive patients who suffered from invasive TCC of the urinary bladder during a 6-year period. Unilateral or bilateral ureteral obstruction was found in 66 patients (54.1%). High stage (T3-T4) and grade (III-IV) tumors were correlated with ureteral obstruction in 89.4% and 83.3% respectively compared to 67.9% and 66.1%, respectively, among patients with normal upper tracts (P < 0.001); 10.6% of the patients with ureteral obstruction had low stage disease, and all of them proved to have involvement of the ureteral orifices on the affected side. The 5-year survival rate of patients with and without ureteral obstruction was 32.2% and 65.9%, respectively (P < 0.001). The presence of ureteral obstruction, particularly in the absence of intravesical involvement of the ureteral orifices, signified a high stage, muscle invasive, and often metastatic tumor in more than 90% of the patients. Ureteral obstruction was an accurate criterion for poor prognostic and was associated with significantly lower, overall and stage-specific, survival rates, despite of radical surgery. We conclude that evidence of ureteral obstruction is an important staging standard and significant prognostic indicator in transitional cell carcinoma of the urinary bladder.

Aged↗
PubMed1977

Evaluation of ureteral obstruction by early intravenous pyelography.

Acute ureteral obstruction was studied in dogs by intravenous pyelography at two, four, six, nine, 12, 24, 48 and 168 hours after total occlusion of the ureter. Ureteral obstruction was correctly diagnosed in all instances, if intravenous pyelography was performed within nine hours from the time of obstruction and if a two hour sequence roentgenogram was obtained. A variably diagnostic rate of 36 to 75 per cent occurred when intravenous pyelography was delayed until 12 hours or later. In ureters with a positive diagnosis, 65 per cent were correctly identified on the 15 minute film, 98 per cent on the one hour film and 100 per cent on the two hour film. Intravenous pyelography should be performed immediately after the onset of renal insufficiency to obtain maximal information, as deterioration in renal function from total ureteral obstruction rapidly causes inadequate excretion and concentration of contrast material and prevents visualization of an obstructed collecting system.

Acute Disease↗
PubMed1977

Late ureteral obstruction mimicking rejection after renal transplantation.

Ureteral obstruction occurring five years or more after renal transplantation is uncommon and may mimic allograft rejection. In 2 patients who had received cadaveric renal allograft, ureteral obstruction was detected six and one-half and five and one-half years after transplantation. In both patients, surgery was needed to restore normal renal function and to prevent further renal damage. Excretory urography is important in the follow-up of patients who have undergone renal transplantation, and conditions such as ureteral obstruction should be ruled out before antirejection treatment is started.

Adult↗
PubMed1988

Bilateral ureteral obstruction secondary to endometriosis.

Endometriotic ureteral obstruction is an uncommon but serious event often unrecognized until hydronephrotic renal atrophy has occurred. A case of bilateral endometriotic ureteral obstruction treated with danazol (Danocrine) is reported, and the literature is reviewed.

Adult↗
PubMed2005

The role of percutaneous nephrostomy in malignant ureteric obstruction.

OBJECTIVES: Uraemia as a result of malignant ureteric obstruction is a recognised event in those with advanced malignancy, usually of pelvic origin, which, if left untreated, is quickly a terminal event. Palliative decompression of the obstructed urinary system, either by percutaneous nephrostomy (PCN), ureteric stent or a combination of both is a recognised method of improving renal function, with presumed low morbidity. The aims of the study were to assess whether PCN placement in malignant ureteric obstruction provided any additional survival benefit or patient morbidity. PATIENTS AND METHODS: The case notes of 32 patients with a mean age of 68.1 years (16 male, 16 female) who underwent PCN drainage for malignant ureteric obstruction were retrospectively analysed. Data on the site of primary malignancy, mode of presentation, improvement in renal function, median survival, conversion to internal ureteric stents and intervention-related complications were collected for analysis. RESULTS: The median survival following PCN insertion was 87 days and was unrelated to the patient's age and renal function. Those patients with primary underlying gynaecological malignancies appeared to survive almost 4 times as long as those with underlying primary bladder cancer. Renal function took a mean of 16.8 days to reach a nadir. Almost 79% of patients were able to be discharged from hospital--each patient, however, being re-admitted back to hospital on average 1.6 times prior to their death through PCN or internal ureteric stent related events. Retrospective "useful quality of life" was seen in less than half of the patient cohort. CONCLUSIONS: In the presence of malignant ureteric obstruction, palliative percutaneous urinary diversion may be performed and is effective in improving renal function. However, long-term survival is limited and should, therefore, be performed only when the views and wishes of the patient and carers are taken into account and if there is a definitive treatment plan available for the patient as quality of life can be suboptimal.

Aged↗
PubMed1991

Role of vasopressin in rats with bilateral ureteral obstruction.

After unilateral release of bilateral ureteral obstruction (BUO), there is a significant increase in renal vasoconstriction that accounts for the marked decrease in glomerular filtration rate and effective renal plasma flow seen in this setting. We examined the potential role of antidiuretic hormone (ADH), a vasoconstrictor of the renal circulation, on renal hemodynamics in female Sprague-Dawley rats with BUO of 24-hr duration. Rats with BUO had significantly higher plasma values of ADH 65.1 +/- 12.2 vs. 12.1 +/- 4.1 pg/ml), sodium (145.4 +/- 0.91 vs 138.6 +/- 1.06 mEq/liter), and osmolality (375.6 +/- 2.0 vs 310.1 +/- 3.6 mOsm/kg) than sham-operated rats. Rats with BUO pretreated with enalapril, an angiotensin-converting enzyme inhibitor, before obstruction had somewhat higher, but not significantly different, plasma values for ADH (84.6 +/- 20.8 pg/ml) than rats with BUO not given enalapril. Rats with unilateral ureteral obstruction of 24-hr duration had plasma levels of ADH (8.2 +/- 1.3) not different from those in sham-operated rats. Rats with BUO pretreated with a specific antagonist of the V1-type receptor for ADH had significantly greater values for the glomerular filtration rate (2.31 +/- 0.24 vs 1.44 +/- 0.08 ml/min/kg body wt) and the effective renal plasma flow (8.95 +/- 0.71 vs 3.81 +/- 0.44 ml/min/kg body wt) and significantly lower values for mean arterial pressure (140.3 +/- 2.0 vs 159.1 +/- 5.5 mm Hg) than did BUO rats not given the antagonist. The results indicate that high levels of ADH play an important role in the decrease in the glomerular filtration rate and effective renal plasma flow observed in rats with BUO of 24 hr. The significant increase in ADH levels after BUO of 24-hr duration may be due to an increase in osmotic stimulation as a consequence of hypernatremia. Activation of the renin-angiotensin axis, known to occur after BUO or unilateral ureteral obstruction of 24-hr duration, does not appear to have a role in the increased circulating levels of ADH.

Animals↗
PubMed1983

Calycovesicostomy for total ureteral obstruction after renal transplantation.

Surgical reconstruction for ureteral obstruction is necessary in 1 to 10 per cent of renal transplants. On an acute basis edema, ischemia, lymphocele and hematoma formation cause ureteral obstruction. Chronic etiologies include ureterovesical obstruction and retroperitoneal or ureteral fibrosis. Options for repair are myriad and include repeat ureteral reimplantation, pyeloureterostomy, ureteroureterostomy, pyelocystostomy and calycovesicostomy. We report on the desirability of calycovesicostomy as a last resort option for total ureteral obstruction after renal transplantation.

Adult↗
PubMed1984

Ureteral obstruction secondary to perianeurysmal fibrosis.

Ureteral obstruction secondary to perianeurysmal fibrosis is rare. We have added 3 cases to the 61 cases previously reported in the literature. Perianeurysmal fibrosis should be included in the differential diagnosis of ureteral obstruction particularly when there is medial deviation of the ureters. Abdominal ultrasound is a valuable screening test to confirm the presence of perianeurysmal fibrosis. Treatment must be individualized for each patient, but the majority of patients will benefit most from preoperative urinary drainage followed by aneurysmectomy and ureterolysis.

Aged↗
PubMed1983

Ureteric obstruction after dacron vascular replacement.

Ureteric obstruction is a recognised complication of aortic bifurcation grafting where the graft material is in close proximity to the ureter as it crosses the common iliac vessels. We have assessed the value of routine postoperative urography in (1) a retrospective 6-year study of ruptured aortic aneurysm repair (11 patients reviewed) and (2) a prospective 18-month study of all patients receiving intra-abdominal dacron grafts (24 assessable patients) in a district general hospital. Renal function was normal in all cases and only 1 ureter was shown at urography to be minimally dilated but not significantly obstructed out of 32 'at risk' ureters in 18 patients in the 2 studies. This complication is uncommon, and no particular advantage can be demonstrated in positioning the ureters either behind or in front of the graft limbs. There is no place for routine urography which should be reserved for the patient with symptoms of ureteric obstruction.

Aged↗
PubMedDate not supplied

Microscopic hematuria and calculus-related ureteral obstruction.

The evaluation of patients with ureteral calculi in the emergency department has historically included urinalysis (UA) and intravenous pyelograms (IVP). This retrospective study was done to determine if a statistically significant relationship existed between the degree of calculus-related ureteral obstruction, proven by IVP, and the presence or absence of microscopic hematuria. Urine red blood cells were recorded as less than 3 rbc/hpf (negative) or greater than or equal to 3 rbc/hpf (positive). IVPs were recorded as nonsevere or severe. IVP criteria were based on the presence or absence of extravasation, greater than 2-hour ureteral filling times, and a numerical scoring system of 1 to 4 for ureteral or calyceal dilatation and nephrogenic effect. Eighty-nine men (72%) had non-severe obstructions and 34 (28%) had severe obstructions. Twenty-five women (68%) had nonsevere obstructions and 12 (32%) had severe obstructions. Of the 28 patients with normal UAs, 11 had severe ureteral obstructions and 17 had nonsevere ureteral obstructions. There were no statistically significant differences between the presence or absence of significant microscopic hematuria and the presence or absence of severe ureteral obstruction. Microscopic hematuria is neither sensitive nor specific in determining the degree of calculus-related ureteral obstruction.

Emergency Medical Services↗
PubMed1996

Control of p53 and p21 (WAF1) expression during unilateral ureteral obstruction.

Long-term unilateral ureteral obstruction (UUO) initiates a series of renal events leading to proliferation of interstitial fibroblasts and proliferation/repair of tubular cells. This is evidenced by significant increases in proliferating cell nuclear antigen (PCNA) positive nuclei during UUO. Several pathologic settings requiring DNA replication and/or DNA repair are dependent upon the expression of p53 and at least one of two p53-dependent proteins, termed p21 (also called WAF1) and GADD45. We therefore sought to determine if p53, p21 (WAF1) or GADD45 mRNA levels were changed in obstruction. There was a progressive increase in the amount of p53 mRNA and p21 (WAF1) mRNA at 1, 3, 5 and 8 days of continuous UUO. The amount of GADD45 mRNA was found not to change. Treatment of the experimental animals with an ACE inhibitor on day 4 through day 8 of UUO significantly blunted the increase in p53 and p21 (WAF1) expression. ACE inhibitor treatment also significantly decreased the number of PCNA-positive renal cell nuclei during UUO. These results suggest that during ureteral obstruction the p53 and p21 (WAF1) genes are activated. ACE inhibitor treatment reduces p53 and p21 (WAF1) expression. This reduction is at least in part due to an inhibition of interstitial cell proliferation.

Animals↗
PubMed1988

Pelviometry in the normal and the partially obstructed porcine kidney: recordings before and three weeks after application of ureteral obstruction.

In 11 pigs a standardized proximal ureteric obstruction was applied. The effect of the obstruction was examined three weeks later. In both the normal and the obstructed systems the pressure-volume relationship was exponential. Mean pelvic capacity increased from 6.5 ml. to 44.1 ml. (p less than 0.002). Mean intrapelvic baseline pressure increased from 10.0 to 16.8 cm. H2O (p less than 0.02), and this parameter correlated positively to volume (rS = 0.79 - p less than 0.05). There was a slight decrease in the relative function of the obstructed kidney on renography (from 49% to 39% of the total renal function), but this was not significant. The decrease in function was correlated to the increase in capacity (rS = -0.69 - p less than 0.05). In this series renal deterioration occurred in the hydronephrotic kidneys, and at least in this model of acute ureteral obstruction there was no support for the theory that hydronephrotic transformation is a compensatory mechanism which protects the kidney when the upper urinary tract is obstructed.

Animals↗
PubMed1993

Recovery of ureteric motility following complete and partial ureteric obstruction.

Complete and partial ureteric obstruction was created in 2 groups of 10 mongrel dogs by placing a ligature around, or inserting a fine bore plastic stent into, the lower end of the left ureter (Groups 1 and 2). After 4 weeks the ligature or stent was removed, a 2.5-cm segment of ureter was harvested for in vitro analysis and the ureter reimplanted into the bladder. Pelvic and ureteric pressures and motility were recorded before, during and after the period of obstruction via a subcutaneously placed nephrostomy tube. Pre-obstruction resting intra-ureteric pressure was 2.1 +/- 0.3 mm Hg (mean +/- SEM), with regular contractions 8.9 +/- 0.7/min of 36.2 +/- 1.2 mm Hg amplitude. After 4 weeks of obstruction, contractility was abolished in Group 1 but increased in Group 2, 71.5 +/- 3.3 mm Hg, with irregular multiphasic contractions seen following diuresis. Intra-ureteric pressure was 16.3 + 1.2 mm Hg in Group 1 and 9.3 + 1.2 mm Hg in Group 2. In vitro experiments confirmed the patterns of contractility seen in vivo. Eight weeks after reimplantation the ureter returned to normal rhythm and rate in Group 1, but increased contractility persisted both in vivo and in vitro in Group 2.

Animals↗
PubMed2003

Renal hemodynamic and ureteral pressure changes in response to ureteral obstruction: the role of nitric oxide.

PURPOSE: Triphasic changes in renal blood flow and ureteral pressure after unilateral ureteral obstruction have long been known. The contribution of nitric oxide to the decline in renal blood flow and ureteral pressure in unilateral ureteral obstruction was studied in this model using arginine infusion and by studying the effect of 2 inhibitors of nitric oxide synthase (NOS). MATERIALS AND METHODS: Left ureteral obstruction was created in dogs. Renal blood flow and ureteral pressure were monitored. Groups 1 to 4 underwent unilateral ureteral obstruction and group 5 dogs underwent sham operation. Groups 2 to 5 received an infusion of arginine at hour 18 of obstruction that was sustained for 1 hour. In addition, NOS inhibitors were administered to dogs in groups 3 (N-monomethyl-L-arginine) and 4 (triamcinolone diacetate). RESULTS: Arginine administration at 18 hours of obstruction caused a significant increase in renal blood flow and ureteral pressure compared to sham operated animals. Triamcinolone diacetate eliminated the increase in renal blood flow and ureteral pressure, whereas N-monomethyl-L-arginine did not, reflecting the competitive nature of its inhibition of NOS. CONCLUSIONS: Arginine infusion 18 hours after unilateral ureteral obstruction led to increases in renal blood flow and ureteral pressure that were not seen in control animals. These results suggest that the nitric oxide system of the kidney is activated in unilateral ureteral obstruction. Since the addition of arginine is accompanied by an increase in renal blood flow and ureteral pressure, it further suggests that a lack of availability of substrate for NOS may explain the decrease in renal blood flow and ureteral pressure in obstruction. Providing substrate may be a way of maintaining renal blood flow in unilateral ureteral obstruction.

Animals↗
PubMed2003

Use of nephrostomy tubes in ureteric obstruction from incurable malignancy.

Malignancy may produce ureteric obstruction. This obstruction may be relieved by inserting a nephrostomy tube. All 31 cases of malignant ureteric obstruction from a single institution were retrospectively analysed. The commonest indications for nephrostomy tube insertion were renal failure (87%) and flank pain with hydronephrosis (13%). The mean serum creatinine levels pre and post insertion were 481 and 170 micromol/l, representing significant improvement (p<0.01). The complication rate was 13%, relating to tube blockage or dislodgement. Survival of patients was significantly worse if their malignancy was not resectable or suitable for chemotherapy (p=0.01). However, incurable patients still survived for a mean of 232 days, and although 46% of this time was spent as an inpatient, it did not differ significantly from the inpatient rate of curable patients (31%, p=0.1). Nephrostomy tube insertion should be considered for all palliative cases of malignant ureteric obstruction.

Aged↗