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Objective: To assess the impact of kidney stone disease (KSD) and its treatment on the health-related quality of life (HRQOL) of high-risk stone formers with hyperparathyroidism, renal tubular acidosis, malabsorptive disease, and medullary sponge kidney., Patients and Methods: The Wisconsin Stone Quality of Life questionnaire was used to evaluate HRQOL in 3301 patients with a history of KSD from 16 institutions in North America between 2014 and 2020. Baseline characteristics and medical history were collected from patients, while active KSD was confirmed through radiological imaging. The high-risk group was compared to the remaining patients (control group) using the Wilcoxon rank-sum test., Results: Of 1499 patients with active KSD included in the study, the high-risk group included 120 patients. The high-risk group had significantly lower HRQOL scores compared to the control group (P < 0.01). In the multivariable analyses, medullary sponge kidney disease and renal tubular acidosis were independent predictors of poorer HRQOL, while alkali therapy was an independent predictor of better HRQOL (all P < 0.01)., Conclusions: Among patients with active KSD, high-risk stone formers had impaired HRQOL with medullary sponge kidney disease and renal tubular acidosis being independent predictors of poorer HRQOL. Clinicians should seek to identify these patients earlier as they would benefit from prompt treatment and prevention., (© 2024 The Authors. BJU International published by John Wiley & Sons Ltd on behalf of BJU International.)

Objective: To build the Wisconsin Stone Quality of Life Machine-Learning Algorithm (WISQOL-MLA) to predict urolithiasis patients' health-related quality of life (HRQoL) based on demographic, symptomatic and clinical data collected for the validation of the Wisconsin Stone Quality-of-Life (WISQOL) questionnaire, an HRQoL measurement tool designed specifically for patients with kidney stones., Material and Methods: We used data from 3206 stone patients from 16 centres. We used gradient-boosting and deep-learning models to predict HRQoL scores. We also stratified HRQoL scores by quintile. The dataset was split using a standard 70%/10%/20% training/validation/testing ratio. Regression performance was evaluated using Pearson's correlation. Classification was evaluated with an area under the receiver-operating characteristic curve (AUROC)., Results: Gradient boosting obtained a test correlation of 0.62. Deep learning obtained a correlation of 0.59. Multivariate regression achieved a correlation of 0.44. Quintile stratification of all patients in the WISQOL dataset obtained an average test AUROC of 0.70 for the five classes. The model performed best in identifying the lowest (0.79) and highest quintiles (0.83) of HRQoL. Feature importance analysis showed that the model weighs in clinically relevant factors to estimate HRQoL, such as symptomatic status, body mass index and age., Conclusions: Harnessing the power of the WISQOL questionnaire, our initial results indicate that the WISQOL-MLA can adequately predict a stone patient's HRQoL from readily available clinical information. The algorithm adequately relies on relevant clinical factors to make its HRQoL predictions. Future improvements to the model are needed for direct clinical applications., (© 2020 The Authors BJU International © 2020 BJU International.)

Objective: To identify the clinical and demographic predictors of repeat stone surgery., Materials and Methods: We retrospectively analysed 1496 consecutive patients, aged > 18 years, who underwent stone surgery at our institution in the period from January 2009 to May 2017 and who had at least 12 months of postoperative follow-up. We defined surgical recurrence as repeat surgery on the same renal unit or on the opposite renal unit if the original imaging did not demonstrate significant stones on that side. Characteristics associated with the risk of surgical recurrence in univariate Cox regression analysis were entered into a multivariate model., Results: Most patients underwent ureteroscopy and laser lithotripsy (83.0%). Approximately 60% of the patients had a personal history of stone disease and 50% were obese. Over a mean (median; interquartile range) follow-up of 4.1  (3.9; 2.4-5.9) years, 24.5% of patients had surgical recurrence, with 82% of repeat surgeries performed for symptomatic nephrolithiasis. The factors associated with increased risk of surgical recurrence in the multivariate model were: age <60 years, female gender, malabsorptive gastrointestinal disease, diabetes, recurrent urinary tract infections, personal history of nephrolithiasis, renal stones and bilateral nephrolithiasis. The hazard ratios for these variables ranged within an interval of <0.5 (from 1.30 to 1.71)., Conclusion: We identified eight demographic and clinical factors associated with increased risk of repeat renal stone surgery. These factors could be combined as a numerical count that allows stratification of patients into low-, intermediate- and high-risk subgroups., (© 2019 The Authors BJU International © 2019 BJU International Published by John Wiley & Sons Ltd.)

Objective: To assess whether extreme obesity (body mass index [BMI] ≥ 40 kg/m(2) ) is associated with peri-operative outcomes, overall survival (OS), cancer-specific survival (CSS), or recurrence-free survival (RFS) after surgical treatment for renal cell carcinoma (RCC)., Patients and Methods: After institutional review board approval, we used an institutional database to identify patients treated surgically between January 2000 and December 2014 with a pathological diagnosis of RCC. Comprehensive clinical and pathological data were reviewed. Kaplan-Meier analyses were used to estimate OS, RFS and CSS. Univariate and multivariate Cox proportional hazards analysis was used to evaluate associations with OS, CSS and RFS in patients with extreme obesity, among other known predictive variables., Results: In all, 100 patients (11.9%) with a BMI ≥ 40 kg/m(2) and 743 patients (88.1%) with a BMI < 40 kg/m(2) who were treated surgically for RCC were identified. Morbid obesity was not associated with an increased risk of blood transfusion (odds ratio [OR] 1, 95% confidence interval [CI] 0.587-1.70; P = 1.0). The median (interquartile range) length of hospital stay (LOS) was 4 (3-6) days. Morbid obesity was not associated with longer LOS (P = 0.26) or 30-day hospital readmission rates (P = 1.0). Major complications (Clavien ≥ 3a) were recorded in 67 patients (7.95%). BMI ≥ 40 kg/m(2) was not a predictor of major complications (OR 0.58, 95% CI 0.227-1.47; P = 0.251) or 90-day mortality (P = 0.4067). BMI ≥ 40 kg/m(2) was not associated with worse OS (P = 0.7), CSS (P = 0.2) or RFS (P = 0.5). BMI ≥ 35 kg/m(2) was also not associated with worse OS, CSS or RFS (P = 0.3, 0.1, 0.5, respectively). The 5-year OS rate was 68.9% for the entire cohort, including 69 and 70% for patients with BMI < 40 kg/m(2) and BMI ≥ 40 kg/m(2) , respectively (P = 0.69). The 5-year CSS was 79.5% for the entire cohort, including 78.4 and 87.9% (P = 0.16) for patients with BMI < 40 kg/m(2) and BMI ≥ 40 kg/m(2) , respectively. The 5-year RFS rates for BMI < 40 kg/m(2) and BMI ≥ 40 kg/m(2) were 84.1 and 90.6%, respectively (P = 0.48)., Conclusions: Extreme obesity is not associated with worse peri-operative or cancer outcomes after surgery for RCC. Surgery should remain a standard treatment option in well selected morbidly obese patients., (© 2015 The Authors BJU International © 2015 BJU International Published by John Wiley & Sons Ltd.)

Objectives: • To compare the Cyberwand (Gyrus/ACMI, Southborough, MA, USA), a dual-probe ultrasonic lithotrite, with a single-probe ultrasonic lithotrite. • The Cyberwand incorporates coaxial high- and low-frequency ultrasonic probes that work synergistically., Patients and Methods: • An institutional review board-approved, multicentre, randomized controlled trial to compare the Cyberwand to the Olympus LUS-II (Olympus America, Inc., Melville, NY, USA) single-probe lithotrite was performed. • Patients undergoing a percutaneous nephrolithotomy (PCNL) with a target stone > 2 cm in diameter were eligible for the study. • The primary outcome was the time to removal of the targeted stone., Results: • A total of 57 PCNLs were performed after randomization: 25 Cyberwand and 32 LUS-II. • There was no difference (P > 0.05) observed between the two devices for target stone surface area (Cyberwand 526.6 cm³ vs LUS-II 540.1 cm³), time to clearance of target stone (Cyberwand 15.8 min vs LUS-II 14.2 min) and target stone clearance rate (Cyberwand 61.9 mm²/min vs LUS-II 75.8 mm²/min). • Of the patients with stone analysis, hard stones (calcium oxalate monohydrate, brushite and cystine) were noted in 14 (56.0%) of the 25 Cyberwand and 18 (62.1%) of the 29 LUS-II patients. • Fifteen of the 25 (60.0%) Cyberwand and 20 of the 32 (62.5%) LUS-II patients were stone-free after the initial PCNL. • Those patients not rendered stone-free went on to receive a secondary PCNL. • Device malfunction occurred in eight of 25(32.0%) Cyberwand and five of 32 (15.6%) LUS II patients. • Complications were similar in both treatment groups., Conclusion: • No appreciable difference between the dual-probe Cyberwand and the standard ultrasonic Olympus LUS-II lithotrites can be identified., (© 2010 THE AUTHORS. BJU INTERNATIONAL © 2010 BJU INTERNATIONAL.)

Study Type: Therapy (case series)., Level of Evidence: 4., Objective: To determine the implementation of medical expulsive therapy (MET) for ureterolithiasis in one tertiary-care emergency room (ER); referral patterns in the surgical and metabolic follow-up of ureterolithiasis were also assessed., Patients and Methods: In this retrospective review we identified 556 patients with ureterolithiasis in the ER at our centre between 2005 and 2007. Of these, 131 patients met inclusion criteria, including first-time stone formers and no urological visit within the previous 5 years. ER records were reviewed and telephone interviews conducted to determine if MET was used, if the patient was referred to a urologist, if surgery was ultimately required, and if there was ultimately a metabolic evaluation., Results: The mean (range) stone size was 4.2 (2-10) mm. Ten patients were admitted directly from the ER and 121 were discharged home. Of the 121 discharged patients, 48 (40%) were prescribed MET. In all, 46 patients received tamsulosin 0.4 mg and two received doxazosin 2 mg; no patient was prescribed steroids. The mean size of passed stones was statistically significantly lower than that of stones that did not pass (P < 0.05). Patients prescribed MET had a 23% chance of needing surgery, vs 32% in those not prescribed MET (P < 0.05). Seventy-one (61%) patients were followed up by a urologist, 27 (23%) by a primary-care physician, and eight (7%) had no further follow-up. Ultimately, 31 (23%) patients had a metabolic evaluation and it was abnormal in 29 (95%)., Conclusions: In this single-institution ER experience, 40% of patients with symptomatic ureterolithiasis were treated with MET on discharge from the ER. Our data also show that only patients referred to a urologist received a metabolic evaluation. This is notable given that the vast majority of those evaluated were found to have a correctable abnormality.

Objective: To evaluate, in a posthoc analysis of a previous study, whether vitamin D repletion in postmenopausal women with insufficient vitamin D increases urinary calcium excretion, as vitamin D therapy might contribute to hypercalciuria and calcium stones in susceptible individuals, and the effect of vitamin D on the risk of urolithiasis warrants attention., Subjects and Methods: We recruited 18 women at > or =5 years after menopause who had vitamin D insufficiency (serum 25(OH)-vitamin D, 16-24 mg/dL). We excluded women with a history of urolithiasis and kidney disease. Women had one calcium absorption study when vitamin D-insufficient, received vitamin D therapy, and completed a second calcium absorption study when vitamin D-replete. We fed subjects meals that mirrored the nutrient composition from self-reported 7-day diet diaries. To measure calcium absorption, we collected urine for 24 h during both visits., Results: We achieved vitamin D repletion in all women (25(OH)-vitamin D before and after treatment, 22 and 63 mg/dL, respectively; P < 0.001). The mean calcium intake was 832 mg/day. Residual urine specimens were available for 16 women, allowing a measurement of 24-h urinary calcium. Calcium excretion did not change after vitamin D therapy (212 before vs 195 mg/day after; P = 0.60). Of four women with hypercalciuria (>247 mg/day), calcium excretion decreased in three (377-312 mg/day, not significant)., Conclusion: Vitamin D supplementation did not increase the urinary calcium excretion in healthy postmenopausal women. Many stone formers are at risk of premature bone loss, vitamin D insufficiency, or both. Based on the present results we suggest a study of patients with hypercalciuria and nephrolithiasis to determine the risks of vitamin D therapy.

Objective: To evaluate the recurrence-free survival (RFS) rate of patients taking cardioprotective aspirin after intravesical bacille Calmette-Guérin (BCG) for high-grade noninvasive urothelial carcinoma of the bladder, as preventing the recurrence of superficial bladder cancer might decrease patient morbidity and mortality from this disease, and nonsteroidal anti-inflammatory agents (NSAIDs) have shown promise in preclinical prevention through inhibition of the prostaglandin pathway and other mechanisms., Patients and Methods: In all, 43 patients with carcinoma in situ (CIS) and/or high-grade papillary bladder cancer were treated with intravesical BCG. Patients were stratified according to whether they took cardioprotective aspirin after treatment, and Kaplan-Meier curves of RFS were compared by log-rank analysis. Multivariable analysis was used for potentially confounding factors, including maintenance BCG, the presence of CIS, and smoking status., Results: Of patients taking cardioprotective aspirin, the 5-year RFS rate was 64.3%, compared with 26.9% for patients not taking aspirin, with a significantly higher RFS by univariable log rank analysis (P = 0.03). Even after adjusting for the other factors by multivariable analysis, aspirin seems to affect recurrence (hazard ratio 0.179, P = 0.001). Maintenance BCG (hazard ratio 0.233, P = 0.02) and smoking history (hazard ratio 3.199, P = 0.05) also significantly affected recurrence., Conclusion: There was a significantly higher RFS rate in patients taking cardioprotective aspirin after intravesical BCG therapy for bladder cancer. The results of this study support the further investigation of aspirin and other NSAIDs as preventive agents in patients being treated for superficial bladder cancer.

Objective: To evaluate the efficacy of stone volume measured using a three-dimensional (3D) reconstruction of preoperative non-contrast computed tomography (NCCT) as an independent predictor of success after extracorporeal shock wave lithotripsy (ESWL) of upper urinary tract calculi., Patients and Methods: We evaluated preoperative NCCT in 94 patients who had ESWL for solitary upper urinary tract calculi of 4-20 mm in diameter. Axial images were used to measure the skin-to-stone distance (SSD), Hounsfield Unit (HU) density and axial stone diameter. Stone volume was calculated on a volume-rendered 3D image for each stone. Maximum stone length was determined by comparative measurements of each stone in coronal, sagittal and axial planes, and was also measured on a plain abdominal film before ESWL. For ESWL we used the DoliS lithotripter (Dornier Medical Systems, Marrietta, GA, USA). A plain film at 6 weeks was used to categorize patients as stone-free (SF) or with residual stone., Results: In all, 58 (62%) patients were SF and 36 (38%) had RS; the mean stone volume was significantly different between these groups (274 vs 464 microL, P = 0.002). Logistic regression analysis showed that stone volume was the strongest predictor of SF status (P < 0.001), compared to peak HU (P = 0.015), mean HU (P = 0.04) and axial stone diameter (P = 0.006). The body mass index, SSD and maximum stone length on NCCT or a plain film did not predict success. A stone volume of <500 microL best predicted treatment success (P < 0.001) with 72% of patients with a stone volume of <500 microL having a successful outcome, vs only 27% with a stone volume of >500 microL., Conclusion: Our study suggests that stone volume is an optimal predictor of SF status after ESWL of solitary upper urinary tract calculi.

Objective: To evaluate the intermediate-term outcomes of hand-assisted laparoscopic radical nephrectomy (HALRN) for clinically organ-confined renal cell carcinoma (RCC)., Patients and Methods: We retrospectively reviewed patients who had HALRN for clinically organ-confined RCC at the University of Wisconsin from 1996 to 2003. All patients with pathologically confirmed RCC and with >or=3 years of follow-up were included in a retrospective chart review of variables before, during and after HALRN, as well as the clinical outcomes., Results: In all, 75 patients had HALRN in the study period; their mean age was 59 years, body mass index 29 kg/m(2), operative duration 227 min, estimated blood loss 130 mL, and none required conversion to open nephrectomy. The median time to first oral intake was 2.5 days and the median hospital stay 4 days. On pathological examination the mean tumour size was 5.8 cm; 70% were pT1, 26% pT2 and 4% pT3; 82% were clear cell, 9% papillary, 8% chromophobe and 1% collecting duct carcinoma. Of the 65 patients who had a follow-up of >or=36 months (mean 46, range 36-117), the 3- and 5-year disease-free survival rate was 93.4% and 90.2%, respectively; the 3- and 5-year cancer-specific survival rate was 96.5% and 94.4%, respectively., Conclusion: Our study suggests that HALRN is a safe and minimally invasive treatment for managing clinically organ-confined RCC, with good intermediate-term oncological outcomes.

Objective: to develop a reproducible, non-debilitating in vivo murine model of human renal cryoablation using a standard closed argon-delivery system., Materials and Methods: Custom engineered 2-mm conical tip cryoprobes for use on the standard argon-based cryoablation unit (Endocare, Inc. Irvine, CA, USA) were used to create small controllable iceballs (−160 °C) in the mouse kidney. The time to create a 4-mm cryolesion was compared using a contact vs puncture technique in 10 mice. To show consistency of the induced-freeze injury, a 4-mm iceball was created in 20 murine renal units and the time to creation and the size of the resultant cryolesion measured. To investigate lesion regression and histological changes, we created a 4-mm renal cryolesion in 28 mice and killed four each at 1, 3, 7, 14, 21, 28, and 35 days. The measured coronal cross-sectional area of the cryoablation site at necroscopy was compared to the initial calculated area as a percentage. To assess renal preservation, blood urea nitrogen (BUN) and creatinine levels at 1 week after cryoablation or sham ablation was compared (10 mononephric mice in each group)., Results: The time to create the desired iceball was 1.9 times quicker using the puncture vs the contact technique. The mean (sd) time to forming a 4-mm iceball was 35.3 (4.8) s with a mean maximum length of the resultant post-thaw injury of 5.7 (0.5) mm and a 9% coefficient of variance. Regression analysis of the two-dimensional cross-sectional coronal area of the cryolesion showed a statistically significant linear pattern of regression over time (P = 0.037) and classic histological findings. There was no significant difference in the BUN or creatinine levels in mononephric mice 1 week after cryotherapy compared with the sham-ablated controls., Conclusions: We describe a reproducible, non-debilitating, easily manipulated murine model for the study of human renal cryoablation.

Objective: To report our 5-year experience with laparoscopic and percutaneous cryoablation (LCA and PCA) for managing small renal masses., Patients and Methods: We retrospectively analysed patients undergoing LCA and PCA between October 2000 and March 2006 at our institution. After approval from the Institutional Review Board, charts were reviewed retrospectively for variables during and after CA, and for clinical outcomes, the latter including the efficacy of the procedure in achieving overall, cancer-specific and recurrence-free survival., Results: In all, 78 patients had CA of 88 small renal masses, by LCA in 58 and PCA in 20. The median American Society of Anesthesiology score was 3 and the mean body mass index was 30 kg/m(2). All procedures were done under general anaesthesia, with a mean anaesthesia time of 220 min. The mean tumour size was 2.6 cm and the mean hospital stay was 2.1 days. At a mean follow-up of 19 months, the overall, cancer-specific and recurrence-free survival rates were 88.5%, 100% and 98.7%, respectively. Four patients required a repeat treatment due to persistent disease and one had progression to locally advanced disease. Five patients had complications during CA and seven had complications afterward., Conclusion: This study suggests that CA is a safe, minimally invasive treatment option for patients with small renal masses, at the intermediate-term follow-up.

Objective: To determine whether an electrode array with a bipolar radiofrequency ablation (RFA) energy source can be used to perform a haemostatic partial nephrectomy by simultaneously ablating and coagulating renal tissue., Materials and Methods: Lower-pole partial nephrectomy was performed in 12 porcine kidneys using a bipolar RFA system. Intraoperative ultrasonography was used to identify and avoid the collecting system. Tissues were positioned between opposing electrodes and tissue impedance monitored using a proprietary feedback and control algorithm. Ablation time and power, lesion width and length, and tissue thickness were recorded. The kidneys were assessed in vivo to show haemostasis of the remaining renal unit. Collecting system integrity was assessed with methylene blue injection, and the resected tissue analysed histologically., Results: Partial nephrectomies were successful in all 12 porcine kidneys; the mean nephrectomy specimen was 3.2 x 2.6 cm. The total ablation time (sem) per lesion was 211 (15) s and the mean power was 23 W. Methylene blue injection showed an intact collecting system in 11 of the 12 kidneys, and haematoxylin and eosin staining showed a mean zone of necrosis of 9 mm at the resection margin. Ultrasonography revealed flow to the remaining kidneys after RFA and the in vivo assessment of haemostasis revealed no abnormal bleeding or haemorrhage from the kidneys., Conclusions: Applying bipolar RF energy to an electrode array can enable transmural excision of renal parenchyma in vivo in a bloodless fashion without collecting system injury.

Objective: To compare the efficacy of cryoablation and radical nephrectomy for treating implanted VX-2 carcinoma in rabbit kidneys., Materials and Methods: A pilot study was conducted using 27 New Zealand white rabbits to assess the natural history of VX-2 carcinoma in the kidney. VX-2 tumour segments (1 mm(3)) were excised from subcutaneous tumours in carrier rabbits and implanted in the left kidney of study rabbits. The tumours were allowed to grow for 6, 7, 8, 9, 10, 14, 18, 21 and 28 days after implantation. Tumour progression was analysed in the kidney and surrounding serosa, and metastatic tumour presence in the lung, liver, spleen and bladder determined. After this, 80 rabbits were implanted with VX-2 in the lower pole and randomized into one of three groups: group 1, 35 rabbits treated 7 days after VX-2 implantation with cryoablation using a 15-min double-freeze technique and a 5-mm tumour margin target temperature of - 20 degrees C; group 2, 35 rabbits treated with open radical nephrectomy; or group 3, 10 untreated controls. Rabbits were maintained for 22 days and then killed; the kidneys, lungs, liver, spleen, urinary bladder and ureter were removed, and examined grossly and histologically for tumour presence., Results: In the pilot study there was a consistent 50-100 mm(3) tumour after 7 days of growth, with no evidence of metastatic disease. By day 10 the mean kidney tumour was 230 mm(3) and two of three rabbits had metastases in the lung. By day 18 the mean primary tumour was 5504 mm(3) and all rabbits had metastatic disease. In the comparison study, cryotherapy cured 66% of implanted rabbits while nephrectomy cured 64%. All untreated controls had significant local and metastatic tumours. Findings in animals killed at 15 days after treatment showed significant differences between both treatment groups and untreated controls (P < 0.002). There was no difference in disease-free survival between the cryotherapy and open nephrectomy groups (P = 0.78), Conclusion: Both cryoablation and radical nephrectomy were effective in treating implanted VX-2 renal tumours compared with untreated controls. There was no statistically significant difference between cryoablation and nephrectomy.

Objective: To determine which of the known tachykinin receptor subtypes is predominant in the swine ureter., Materials and Methods: Ureters from adult pigs were harvested, cut into longitudinal strips and placed in 10 mL tissue baths containing Krebs buffer, under 4 g of initial tension. The magnitude and frequency of contractions were recorded. Tissues were incubated with 1 micromol/L solutions of peptidase inhibitors (phosphoramidon and captopril) for 1 h to inhibit degradation of peptides and treated with either CP 96,345 (NK-1 receptor antagonist), SR 48,968 (NK-2 receptor antagonist) or saline (control). Concentration-response curves to the tachykinins substance P (SP), neurokinin A (NKA) and neurokinin B (NKB) were determined., Results: Ureteric segments showed a concentration-dependent response to all tachykinins; NKA stimulated increased contractions at a lower concentration than either SP or NKB (P<0.05). This was reflected by the difference in the effective concentration required to obtain half the maximal response (EC50 ) for each of the peptides. The mean (sd) EC50 values were (micromol/L): NKA, 0.2 (0.02); SP, 3.5 (0.7); and NKB, 4.5 (1.7). In addition, the selective NK-2 antagonist (SR 48,968) significantly reduced contractile responses to all peptides, as indicated by a 10-fold rightward shift of the concentration-response curves (P<0. 05), whereas the NK-1 antagonist (CP 96,345) had no significant effect., Conclusion: These results indicate that NK-2 is the predominant tachykinin receptor subtype responsible for contraction of ureteric smooth muscle. The use of mediators which act on NK-2 receptors may have clinical applications for the treatment of ureteric disease.

Objective: To determine the optimal contractile response of isolated ureters to inflammatory mediators and neurotransmitters by evaluating four common methods of ureteric suspension., Materials and Methods: Ureters from adult domestic swine were placed immediately in Krebs buffer and cut into 4-5 mm segments. Four methods of suspension were compared: (i) an unopened ring segment suspended horizontally; (ii) a spirally cut segment (lumen cut open at a 45 degrees and suspended end-to-end); (iii) an open longitudinal segment; and (iv) a closed longitudinal segment. All segments were placed in individual water-jacketed tissue baths containing Krebs buffer, the frequency of contraction measured using a force transducer and registered on a polygraph. The sensitivity of all four segments was tested by measuring the tension and frequency in response to increasing frequencies of electric field stimulation, and by a cumulative concentration-response curve to carbachol., Results: Ureteric segments responded with an increased frequency of contraction depending on the intensity of stimulus to both electric field stimulation and carbachol. However, there were no significant differences in spontaneous levels of contraction, sensitivity or maximal response among the methods of suspension in response to electric field stimulation or carbachol., Conclusion: These results indicate that all four methods of suspending the ureteric segments produce contractile responses sensitive enough to study the action of various neurotransmitters.