The role of HCN channels in peristaltic dysfunction in human ureteral tuberculosis.

OBJECTIVE: To explore the role of HCN channels in ureteral peristaltic dysfunction by comparing the changes in HCN channel levels between normal and tuberculous ureters. METHODS: A total of 32 specimens of human upper ureters were collected by nephrectomy from patients with renal tumor (control group, n = 16) or from patients with renal tuberculosis (experimental group, n = 16); the two groups did not receive radiotherapy, chemotherapy, immunotherapy, or any other special treatment before the surgical procedure. An experimental study on smooth muscle strips of human upper ureters showed variation in contraction amplitude and frequency after adding ZD7288, a specific blocker of HCN channels. The expression of HCN channels in the ureter was confirmed by Western blot (WB) and by confocal analysis of double immunostaining for c-kit and HCN channel proteins. RESULTS: Before the addition of ZD7288, the experimental and control groups showed significant differences in the frequency and amplitude of the spontaneous contraction of isolated ureteral smooth muscle strips. After ZD7288 was added, the frequency and amplitude of the contractions of the ureteral smooth muscle strips were significantly lower in both groups. The differences observed before and after ZD7288 treatment in each group were significant (P < 0.001), and the difference in contraction amplitude observed between the two groups before ZD7288 was also significantly different (P < 0.001). By using WB technology, we showed that the expression of HCN channels was present in normal human ureters, with the expression of HCN4 and HCN1 being the highest; the expression of HCN4 and HCN1 in the control and experimental groups were both statistically significant (P < 0.001). HCN4 and HCN1 were expressed in the mucosal and smooth muscle layers of human control ureters and tuberculous ureters, as revealed by a confocal analysis of double immunostaining for c-kit and HCNs proteins; there were significant differences between the two groups (P < 0.001). CONCLUSION: Four HCN channels are expressed in the ureter, mainly HCN4 and HCN1, suggesting that HCN channels are involved in the peristaltic contraction of ureteral ICCs, which may be an important reason for peristaltic dysfunction in ureteric tuberculosis.

Renal fungus ball: a challenging clinical problem.

INTRODUCTION: We describe a case of renal pelvi-ureteric fungus ball managed with placement of two nephrostomy tubes and amphotericin B irrigation through a nephrostomy tube with the other to free drain. CASE REPORT: A 46-year-old man with uncontrolled Type 2 diabetes mellitus was referred to the urology clinic for workup of recurrent urinary tract infection. Urine culture grew Candida albicans. The patient was started on oral fluconazole therapy. Cystoscopy and cystogram revealed a grade 3 left vesicoureteral reflux and right retrograde pyelogram revealed a filling defect in the right renal pelvis extending into the proximal ureter with severe hydroureteronephrosis. Two nephrostomy tubes were placed (mid-pole and lower pole) to ensure that the system was not obstructed. Amphotericin B (50 mg/1000 ml normal saline) irrigation was then instilled through the mid-pole nephrostomy tube at a rate of 30 ml/h with the lower pole nephrostomy tube to free drain. An antegrade nephrostogram was performed after 5 days of amphotericin B instillation, showing complete resolution of the fungus ball. The patient is awaiting definitive minimally invasive management of the distal ureteral narrowing. COMMENTS: Renal and pelvi-ureteric fungus ball is a challenging clinical entity. It must be addressed promptly and efficiently to be successful. We describe a minimally invasive approach that was tolerated well and resulted in complete clearance of the fungus ball in a relatively short time frame.

Effect of the combination of clarithromycin and amikacin on Pseudomonas aeruginosa biofilm in an animal model of ureteral stent infection.

OBJECTIVES: An experimental study was performed to evaluate both in vitro and in vivo the efficacy of clarithromycin coating combined with systemic amikacin in preventing ureteral stent biofilm infection due to Pseudomonas aeruginosa. METHODS: The activities of the two antibiotics were studied in vitro in the absence or in the presence of biofilm. For the in vivo study we evaluated a control group without bacterial challenge to evaluate the sterility of the surgical procedure, a challenged control group that did not receive any antibiotic prophylaxis and three challenged groups that received (i) 15 mg/kg intraperitoneal amikacin immediately after stent implantation, (ii) clarithromycin-coated ureteral stents where 0.2 cm² sterile ureteral stents were incubated in 10 mg/L clarithromycin solution for 30 min immediately before implantation, and (iii) intraperitoneal amikacin plus a clarithromycin-coated ureteral stent at the above concentrations. RESULTS: The in vitro studies showed that the biofilm was strongly affected by the presence of clarithromycin and, in its presence, amikacin had MICs and MBCs lower than those obtained in the absence of clarithromycin. For the singly treated groups, intraperitoneal amikacin showed the strongest effect on bacterial numbers. A clarithromycin coating combined with systemic amikacin showed an efficacy that was higher than that of each single compound. CONCLUSIONS: The prevention of ureteral stent Pseudomonas biofilm infection was enhanced by impregnation of the stent with clarithromycin combined with systemic amikacin.

Cryopreserved arterial homografts vs silver-coated Dacron grafts for abdominal aortic infections with intraoperative evidence of microorganisms.

OBJECTIVE: The gold standard for the treatment of abdominal aortic infections remains controversial. Cryopreserved arterial homografts and silver-coated Dacron grafts have both been advocated as reasonable grafts. Direct clinical or experimental comparisons between these two treatment options have not been published before. This study compared cryopreserved arterial homografts and silver-coated Dacron grafts for the treatment of abdominal aortic infections in a contaminated intraoperative field. METHODS: From January 2004 to December 2009, 56 patients underwent in situ arterial reconstruction for an abdominal aortic infection. Patients with negative intraoperative microbiologic specimens were excluded. We compared 22 of 36 patients (61%) receiving cryopreserved arterial homografts (group A) vs 11 of 20 (55%) receiving a silver-coated Dacron graft (group B). Primary outcomes were survival and limb salvage; secondary outcomes were graft patency and reinfection. Direct costs of therapy were also calculated. RESULTS: Thirty-day mortality was 14% in group A and 18% in group B (P >.99), and 2-year survival rates were 82% and 73%, respectively (P = .79). After 2 years, limb salvage was 96% and 100%, respectively (P = .50), whereas graft patency was 100% for both groups. Major complications were an aneurysmal degeneration in group A and graft reinfection in group B (n = 2). Median direct costs of therapy (in US $) were $41,697 (range, $28,347-$53,362) in group A and $15,531 (range, $11,310-$22,209) in group B (P = .02). CONCLUSIONS: Our results show comparable effectiveness between cryopreserved arterial homograft and silver-coated Dacron graft in the contaminated operative field with respect to early mortality and midterm survival. Graft-inherent complications, aneurysmal degeneration for homografts, and reinfection for silver graft, were also observed. The in situ arterial reconstruction with homografts is nearly three times more expensive than with silver graft.

[A case of Candida parapsilosis fungal balls in the urinary tract associated with a retrocaval ureter].

A 70-year-old man with a medical history of diabetes mellitus presented to a local clinic with seven days history of right flank pain and fever. Because there was no symptomatic improvement after one-week antibiotic administration, abdominal ultrasonography and computed tomographic scans were performed to show mass lesions in the right hydropelvis, and he was transferred to our hospital. Retrograde pyelography revealed a retrocaval ureter and a ureteral stent was indwelt. After the symptoms improved, the lesions were removed by percutaneous nephrostomy and fungal balls were diagnosed as Candida parapsilosis after culture. After intermittent one-week irrigation of the renal pelvis with normal saline, the nephrostomy tube was removed. In six-month follow-up, mild hydronephrosis remains without fungal ball recurrence. To the best our knowledge, there has been no case report of Candida parapsilosis fungal balls in the urinary tract.

Ureteral stent symptoms and associated infections: a biomaterials perspective.

Ureteral stents are commonly used in the field of urology, and, given their indwelling nature, are often a nidus for infection and a cause of discomfort. To minimize symptoms, the urologic surgeon should first consider whether a stent needs to be placed at all. Softer stents do not seem to improve patient comfort. Stents that are too long, specifically those that cross the midline of the bladder, significantly increase the frequency of stent-related symptoms. Administering alpha blockers while the stent is indwelling can reduce these symptoms. Antibiotic prophylaxis or concomitant antibiotic administration does not seem to reduce the incidence of stent-related urinary tract infection. At present, drug-eluting stents have shown the most promise for inhibiting bacterial adhesion and biofilm formation. Future stent designs that maintain drainage of the kidney and ureter while minimizing inflammation and contact with the urothelium will improve patient outcomes. By better understanding the basic pathways of bacterial adhesion to biomaterials, new stents and medications that target these mechanisms can be developed to eliminate bacterial adhesion and infection in patients with ureteral stents.

The antimicrobial peptide tachyplesin III coated alone and in combination with intraperitoneal piperacillin-tazobactam prevents ureteral stent Pseudomonas infection in a rat subcutaneous pouch model.

We investigated the efficacy of Tachyplesin III alone or combined with piperacillin-tazobactam (TZP) to prevent biofilm formation in vitro and in a rat model of Pseudomonas aeruginosa ureteral stent infection. We have observed that in vitro TZP, in presence of Tachyplesin III, showed minimal inhibitory concentrations (MIC)s twofold and minimal bactericidal concentrations (MBC)s eightfold lower. The in vivo study showed that rats that received intraperitoneal TZP showed the lowest bacterial numbers. Tachyplesin III combined with TZP showed efficacies higher than that of each single compound. Coating ureteral stents with Tachyplesin III is able to inhibit bacterial growth up to 1,000 times.

Beware! Fungal urosepsis may follow endoscopic intervention for prolonged indwelling ureteral stent.

We present a 38-year-old lady with a prolonged indwelling ureteral stent that had been placed for pain relief after development of Steinstrasse following extracorporeal lithotripsy for a 2.5-cm left renal calculus. The patient developed candidal urosepsis within 6 hours after ureteroscopy and percutaneous nephrolithotomy (PCNL) for the removal of residual fragments. She subsequently recovered on systemic antifungal therapy in the form of intravenous amphotericin B and achieved complete stone clearance after repeat ureteroscopy and PCNL. Fungal urosepsis is known to complicate the postoperative course in chronically debilitated patients with poor nutritional status or those with diabetes or other significant comorbities. To our knowledge, this is the first reported case of a patient with no significant comorbities developing fungal urosepsis after endoscopic intervention for a long-term indwelling ureteral stent.

Microscopic and ultrastructural lesions of the ureter and renal pelvis in sows with regard to Actinobaculum suis infection.

Tissues from ureter and renal pelvis of 18 sows naturally (n = 15) and experimentally (n = 3) infected with Actinobaculum suis (former Actinomyces, Eubacterium suis) were studied using light and scanning as well as transmission electron microscopy. The results were compared with the findings from 11 clinically healthy sows as controls. The lesions in both the ureter and renal pelvis of naturally and experimentally infected animals were similar. In severe cases there were necrotizing ureteritis and pyelitis with accumulation of bacterial colonies in some cases. Several superficial epithelial cells were found phagocytosing necrotic debris. In mild cases the main lesions included epithelial cell hyperplasia, desquamation of the superficial epithelial cells and goblet cell metaplasia with intraepithelial cyst formation. The goblet cells were found in the superficial as well as in the intermediate cell layers. Generally, it was observed that severe purulent ureteritis and pyelitis/ pyelonephritis in sows were to be expected only in mixed infection of A. suis with other bacteria. The findings were compared and discussed with the changes in the infected urinary bladder of sows and the alterations induced by urinary tract infection in man.

[Complex tubercular ureteral stenoses (report of 2 cases treated with permanent double-J catheter]. / Sténoses urétérales complexes tuberculeuses (à propos de deux cas traités par sonde double J définitive).

Two patients presenting complex tuberculous ureteral strictures on an only existing kidney were treated with definitive double J stent changed every 6 months. This treatment modality was well tolerated. On the basis of two cases and literature review, different therapeutic measures are discussed.

[Bladder candidosis after renal transplantation: contribution of ultrasonography]. / Candidose vésicale chez le transplanté rénal : apport de l'Echographie.

Candidosis of the ureter and the bladder is an infrequent complication after renal transplantation. A case occurring early after kidney transplantation is reported in a patient presenting with candiduria. Ultrasound examination detected several fungal bezoars, presenting as a proliferating, avascular lesions, located within the ureter and the bladder. It allowed to demonstrate the rapid extension of lesions, in spite of a medical treatment, leading to a successful endoscopic removal of fungus balls.

[Ureteral hydronephrosis secondary to appendicular abscess]. / Ureterohidronefrosis secundaria a absceso apendicular.

OBJECTIVE: To report a case of ureterohydronephrosis secondary to an undiagnosed appendiceal abscess. METHODS/RESULTS: Herein we describe a case of a 4-year-old girl with right ureterohydronephrosis arising from extrinsic compression of the right ureter due to an undiagnosed appendiceal abscess. The patient was treated with intravenous antibiotics and the abscess was drained. Regular isotope and US assessments showed both the residual retroperitoneal fibrosis and renoureteral dilation had decreased. CONCLUSIONS: Acute appendicitis is still the most common cause of emergency abdominal operations in children. Although the symptoms are easily recognizable and generally lead to the correct diagnosis in most cases, the peculiarities of childhood can lead to errors in the diagnosis resulting in the complications reported herein. We emphasize the usefulness of ultrasound in the diagnosis and conservative treatment is advocated.