Chronic ureteric obstruction and its impact on the coordinating mechanisms of peristalsis (Pyeloureteric Pacemaker System)

Summary We present the results of a study designed to characterise urine transport in the healthy and chronically obstructed upper urinary tract. Fifteen healthy and 11 hydronephrotic pigs were used; experimental hydronephrosis was produced by partially obstructing the ureter. Data consisting of the peristaltic rate, bolus volume, and the urine flow rate were collected and related to varying increments of diuresis. The transmission characteristics of renal pelvic to ureteric contractions were studied by extracellular electrodes. Similarly, in hydronephrotic preparations we studied the transmission between the proximal and middle pelvis to the ureter. In healthy preparations, the contraction frequency of the renal pelvis and the ureter is identical, while in obstructive cases, the contraction frequency of the upper pelvis is not coordinated with the lower pelvis or ureter. While diuresis increased bolus volume to a maximum of 1,200% in the healthy and 660% in the hydronephrotic kidney, the peristaltic rate changed by only 45% and 50% respectively. The results of this study show that chronic ureteric obstruction alters the coordination of ureteric peristalsis and thereby disrupts the pacemaker mechanisms of the renal pelvis.     

Effects of beta-adrenergic agents on the pacemaker of ureteral peristalsis

An electromyographic study of the responses of the pelvicalyceal border which is the pacemaker region of ureteral peristalsis, and of the renal pelvis and ureter to dobutamine and terbutaline, beta 1- and beta 2-adrenergic stimulants, respectively, was performed using isolated canine pelviureteral preparations. The beta 1-adrenergic stimulant produced a marked enhancement of discharge potential in the pacemaker region, but, in the renal pelvis and ureter, it did not evoke any noticeable response. Application of the beta 2-adrenergic stimulant led to disappearance of discharges in the renal pelvis and ureter, whereas the pacemaker region continued to exhibit regular discharges. These findings seem to suggest the presence in the pelvicalyceal border of a group of cells which, unlike other smooth muscle cells, respond to beta-adrenergic agents in a fashion similar to the cardiac pacemaker, namely, stimulated by beta 1-adrenergic stimulants and not inhibited by beta 2-adrenergic stimulants.     

Renin-angiotensin system in ureteric bud branching morphogenesis: insights into the mechanisms

Branching morphogenesis of the ureteric bud (UB) is a key developmental process that controls organogenesis of the entire metanephros. Notably, aberrant UB branching may result in a spectrum of congenital anomalies of the kidney and urinary tract (CAKUT). Genetic, biochemical and physiological studies have demonstrated that the renin–angiotensin system (RAS), a key regulator of the blood pressure and fluid/electrolyte homeostasis, also plays a critical role in kidney development. All the components of the RAS are expressed in the metanephros. Moreover, mutations in the genes encoding components of the RAS in mice or humans cause diverse types of CAKUT which include renal papillary hypoplasia, hydronephrosis, duplicated collecting system, renal tubular dysgenesis, renal vascular abnormalities, abnormal glomerulogenesis and urinary concentrating defect. Despite widely accepted role of the RAS in metanephric kidney and renal collecting system (ureter, pelvis, calyces and collecting ducts) development, the mechanisms by which an intact RAS exerts its morphogenetic actions are incompletely defined. Emerging evidence indicates that defects in UB branching morphogenesis may be causally linked to the pathogenesis of renal collecting system anomalies observed under conditions of aberrant RAS signaling. This review describes the role of the RAS in UB branching morphogenesis and highlights emerging insights into the cellular and molecular mechanisms whereby RAS regulates this critical morphogenetic process.     

Paradigm shift from classic anatomic theories to contemporary cell biological views of CAKUT

Ectopic budding of the ureter from the Wolffian duct is the first ontogenic misstep that leads to many-if not all-congenital anomalies of the kidney and urinary tract (CAKUT). The ectopia results in hypoplastic kidney, ectopia of ureterovesical orifice, urinary outflow obstruction and/or reflux. Studies in several mutant mouse models have verified that ectopic ureteric budding indeed precedes formation of CAKUT. Often, the genes involved in navigating ureteric budding to the correct site also regulate later ontogenic events of the kidney and urinary tract. The wide spectrum of CAKUT, for example, multicystic dysplastic kidney, megaureter and atretic ureter, portray the additional important functions of these same genes that are activated at multiple sites and stages during the normal morphogenesis of the kidney and urinary tract     

腰部切口联合经尿道电切肾、输尿管全切术

目的探讨经尿道输尿管口电切在肾、输尿管全切术中的价值. 方法 2002年1月～2003年9月,我院采用腰部切口联合经尿道电切肾、输尿管全切术治疗28例肾盂、输尿管上段移行细胞癌.首先经尿道电切患侧输尿管口,然后经腰部切口切除肾及全长输尿管,术后留置导尿管7 d. 结果手术时间70～95 min,平均81 min.无尿漏、严重血尿及伤口感染等并发症.术后住院7～9 d,平均7.4 d.28例随访8～15个月,平均12个月,无肿瘤复发. 结论腰部切口联合经尿道电切肾、输尿管全切术创伤小、恢复快、安全.     

Bilateral extracorporeal shock wave lithotripsy in a spinal cord injury patient with a cardiac pacemaker.

OBJECTIVES: To review the precautions to be observed before and during extracorporeal shock wave lithotripsy (ESWL) in spinal cord injury (SCI) patients with a cardiac pacemaker and the safety of bilateral ESWL performed on the same day. DESIGN: A case report of bilateral ESWL in a SCI patient with a permanent cardiac pacemaker. SETTING: The Regional Spinal Injuries Centre, Southport, the Lithotripsy Unit, the Royal Liverpool University Hospitals NHS Trust, Liverpool, and the Department of Cardiology, Manchester Royal Infirmary, Manchester, UK. SUBJECT: A 43-year-old male sustained a T-4 fracture and developed paraplegia with a sensory level at T-2. During the post-injury period, he developed episodes of asystole requiring implantation of a dual chamber (DDD) permanent pacemaker. Twenty-one months later, he developed a right ureteric calculus with hydronephrosis. A radio-opaque shadow was seen in the left kidney with no hydronephrosis. During right ureteric stenting, the ureteric stone was pushed into the renal pelvis. 1,500 shock waves were delivered to this stone on the right side, followed by ESWL to the left intra-renal stone with 1250 shock waves. RESULTS: The patient tolerated ESWL to both kidneys. The pacemaker was reprogrammed to a single chamber ventricular pacing mode at 30 beats per minute with a reduced sensitivity during lithotripsy. There were no untoward cardiac events during or after lithotripsy. The serum creatinine was 45 micromol/l before lithotripsy and 44 micromol/l two weeks after ESWL. CONCLUSION: SCI patients with a cardiac pacemaker may be able to undergo extracorporeal shock wave lithotripsy following temporary reprogramming of the pacemaker. Bilateral, simultaneous ESWL is safe in the vast majority of patients provided that there is no risk of simultaneous ureteric obstruction by stone fragments. However, it should be remembered that a decrease in renal function could occur following bilateral ESWL of renal calculi.     

Ectopic ureter without urinary incontinence despite ureteric orifice in the vestibulum: report of one case

This is one case of ectopic ureter which lacked urinary incontinence despite ureteric orifice in the vestibulum. Case: A 20-year-old woman complained of miction pain. On examination, we found a small orifice in the vestibulum. DIP revealed slight hydronephrosis in the left contracted kidney and normal pyelogram in the right kidney. On cystoscopy, the bilateral ureteral orifices were normal, but we found the head of a catheter placed in the orifice of the vestibulum was passing under the mucosa of the bladder. The abnormal lumen was recognized by introducing an opaque medium through a catheter placed into the orifice of the vestibulum. The diagnosis was an abnormal left ureteral ectopic opening into the vestibulum with left complete duplication of renal pelvis and ureter. Left heminephro-ureterectomy was performed. Some discussions about the ectopic ureteral orifice without incontinence were conducted.     

Eicosanoid synthesis in the isolated human renal pelvis, ureter and bladder

Prostaglandin synthetase inhibitors are used for the treatment of ureteric colic. However, there is controversy regarding the mechanism of action of these drugs. In this study, differential prostaglandin synthesis in the human renal pelvis, ureter and bladder was measured using specific radioimmunoassays and gas chromatography/mass spectrometry. There was a significant quantitative predominance of the smooth muscle constrictor eicosanoids, PGF2 alpha and TXA2 over the dilatory PGE2 in tissue from all sites--renal pelvis, ureter and bladder. The results indicate that prostaglandins play a direct role in smooth muscle activity of the upper urinary tract and the inhibition of this activity with indomethacin indicates a further mode of its action in pain relief in ureteric colic.     

Improved renal transplantation in the rat with a nonsplinted ureteroureterostomy

Orthotopic renal transplantation in the rat is a widely used model in immunology and transplantation-related research. Although numerous modifications of the surgical technique of ureteric reconstruction were evaluated, ureter complications following this reconstruction still occurred frequently. Instead of dividing the ureter in the middle between kidney and bladder (method 1), the anastomosis was performed close to the renal pelvis after cutting the ureter obliquely (method 2), which enlarged the diameter of the ureteral anastomosis 2-fold. The incidence of stenosis of ureteric anastomosis was 12.5% (3/24) using method 1, whereas this complication was avoided completely (0/45) using method 2. Furthermore, the risk of injury to the ureter was reduced, as isolation of the ureter was limited. These modifications improved the last delicate step in the procedure of rat kidney transplantation.     

Effect of calyceal resection on pelviureteral peristalsis in isolated pig kidney

Pelviureteral peristalsis in the isolated pig kidney with calyceal resection was studied by electromyography. Ureteral peristalsis normally remained under control of calyceal pacemakers while at least one of the upper, middle and lower major calyces of the isolated pig kidney was intact. After resection of all these calyces, uncontrolled spontaneous contractions began to arise from the renal pelvis, pelviureteral junction (PUJ) and stump of the ureter. In such kidneys, the PUJ and cut end of the ureter showed discharge potentials with irregular intervals while the potential recorded from the center of the pelvis had virtually constant intervals of discharge. The spontaneous contractions arising in the pelvis were rarely propagated to the PUJ and ureter, and there was irregular antiperistalsis of the ureter generating at the cut end and also irregular ureteral normoperistalsis originating at the PUJ and propagating to the ureter. With increased intrapelvic fluid infusion, the discharge interval of the renal pelvis shortened whereas that of the PUJ and ureter was prolonged. These facts suggest the importance of the calyceal pacemaker both as an origin of ureteral peristalsis and as a supervisor for maintaining normal ureteral peristalsis.     

Dynamics of the urinary tract in longterm vesico-ureteral reflux with infravesical obstruction and infection in pigs; V

In a study of the dynamic function of the urinary tract in infravesically obstructed pigs with vesicoureteric reflux, 5 pigs with 6 refluxing ureters evidenced urinary tract infection after 8 and 10 weeks of obstruction. Examination showed that the median ureteric baseline activity had decreased to 0.0 A.P./min (action potentials/min). During bladder filling, no increase in activity was seen, although there was pressure equilibration between the bladder and the renal pelvis, when the reflux producing bladder pressure was reached. Only a few episodes of retrograde activity were recorded during the bladder filling. 46% of the ureteric contractions were incomplete and stopped in the mid-third of ureter. The study showed the severe, irreversible impairment of ureteric function when subjected to not only reflux and obstruction but also infection.     

Immunohistochemical detection of neuronal plexuses and nerve cells within the upper urinary tract of pigs.

OBJECTIVE: To investigate the distribution and topography of nervous structures within the renal pelvis and upper part of the ureter of pigs, and thus help to determine the origin, propagation and mechanisms of the modulation of pelvi-ureteric peristalsis. MATERIALS AND METHODS: Whole-mount preparations of renal pelves from adult pigs were stained using a universal immunostaining method with streptavidin-alkaline phosphatase. Anti-neuron-specific enolase antibody and anti-neurofilament antibody were used as neuronal markers. RESULTS: The patterns of neuronal structures differed between the renal calyces, renal pelvis and upper ureter. In the calyx, there was one single dense nerve plexus; this network contained relatively thin nerve fibres running both circularly and longitudinally. In the wall of the renal pelvis and upper ureter there were two neuronal plexuses, one submucosal and another within the muscular layer; these nerve fibres were mainly orientated longitudinally. Some single nerve cells were also found at the pelvicalyceal border. CONCLUSIONS: These findings suggest a potent nervous system within the upper urinary tract of pigs that connects the renal calyces with the renal pelvis, pelvi-ureteric junction and ureter. The presence of these dense neuronal networks and nerve cells within the wall of the renal pelvis and ureter suggests that propagation, coordination and modulation of pelvi-ureteric peristalsis in pigs may arise through intrinsic nervous stimulation.     

Reconstruction of necrotic kidney graft pelvis with a vascularized small bowel patch

Complete necrosis of the pelvis in a transplanted kidney is a rare but particularly severe complication that generally requires removal of the graft. Here, the case of a patient is reported in whom complete necrosis of the ureter and the pelvis occurred a few days after transplantation, while kidney function was excellent. After resection of all necrotic tissue, reconstruction of the pelvis was performed with a vascularized small bowel patch fixed to the renal parenchyma at the border of the intrarenal pelvis. The native ureter was then anastomosed to this reconstructed pelvis. Although the patient suffered from recurrent urinary tract infections in the early postoperative phase, he is now well, with normal kidney graft function and unimpaired urine flow through the reconstructed urinary tract, 18 months after transplantation. This report demonstrates that successful surgical reconstruction after complete necrosis of the renal pelvis in a grafted kidney can be achieved, although the long-term outcome of this graft-saving technique remains to be seen. Received: 15 November 1999 Revised: 31 March 2000 Accepted: 15 November 2000     

Cytologic diagnostic value of voided urine in 60 cases of primary transitional cell carcinoma of the renal pelvis and ureter

Exfoliative urinary cytology was performed on 60 cases of histologically proven TCC (Transitional cells carcinoma) of the renal pelvis and ureter. There were 39 cases of TCC of the renal pelvis. Urine cytology was positive in 27 cases (69.2%); suspicious in 5 cases (12.8%) and negative in 7 cases (17.9%). Significant correlation was found in the frequency of diagnosis and the histological grade of carcinoma. The cytological positive rate in G1 carcinoma was 40%; 71% in G2; 100% in G3. It is considered that the location of tumor in the renal pelvis predominates the urinary cytological positive rate. Urine cytology was positive in 3 cases (33.3%) out of 9 cases of the carcinoma seated in the inferior renal calix, whereas 19 cases (86.4%) from 22 cases in other sites of the renal pelvis (P less than 0.05). The positive rate of urine cytology for 21 cases of TCC of the ureter was 42.9%. The results showed that the secondary ureteric obstruction was an influence on the cytological positive rate.     

Pyelocutaneous ileal conduit for endoscopic control of recurrent renal pelvic tumour. A case report

In a patient with transitional cell carcinoma of the pelvis of a solitary kidney there were extensive recurrences in the ureter and bladder. The treatment consisted of total cystoureterectomy and pyeloileocutaneostomy for urinary diversion and endoscopic control of the pelvic neoplastic growth.     

肾移植术后并发泌尿系统肿瘤的相关因素与临床干预

目的:探讨肾移植术后并发泌尿系统肿瘤的相关因素与临床干预措施.方法:报告9例(10次)此种患者的临床资料.9例肾移植术后均行免疫抑制治疗.肿瘤均发生在自体肾、输尿管和膀胱:肾透明细胞癌、肾肉瘤和膀胱腺癌各1例,肾盂输尿管膀胱移行细胞癌6例,其中1例先发生膀胱腺癌后又发生肾盂输尿管移行细胞癌.肿瘤发生于移植术后8～146个月,且8例发生在应用新型免疫抑制剂之后.患者均有服用龙胆泻肝丸或冠心苏合丸史.8例接受了根治性手术,1例未能手术切除.结果:9例随访8～44个月,未能手术切除1例于术后5个月肝转移死亡.1例肉瘤复发后放弃治疗后死亡.1例膀胱肿瘤复发,行膀胱全切腹壁造瘘术,1例腺癌已出现肺和胸膜转移.另5例最后随访时存活良好.结论:肾移植术后并发泌尿系统肿瘤以移行细胞癌为多;可能与服用含马兜铃的中药和应用新型免疫抑制剂有关;根治性手术治疗、减少免疫抑制剂用量和更换免疫抑制剂种类是主要临床干预措施.     

Consequences to the upper urinary tract after ureteric torsion

Summary The effects of ureteric torsion on the upper urinary tract were studied in 8 pigs. With 5 pigs the distal ureter was mobilised, torted 1 to 5 times and reimplanted into the bladder. With three pigs the proximal ureter was torted 1 to 3 times and re-anastomosed to the renal pelvis. It was shown that a torsion of 1 or 2 times in the distal ureter does not result in ureteral obstruction. However, as little as 360 degrees torsion in the proximal ureter may lead to dysfunction secondary to mechanical obstruction. Histological examination of the ureter showed ischaemic changes only after multiple torsions.