Utsav Bansal

Contribution of GABAA, Glycine, and Opioid Receptors to Sacral Neuromodulation of Bladder Overactivity in Cats.

In α-chloralose–anesthetized cats, we examined the role of GABAA, glycine, and opioid receptors in sacral neuromodulation-induced inhibition of bladder overactivity elicited by intravesical infusion of 0.5% acetic acid (AA). AA irritation significantly (P < 0.01) reduced bladder capacity to 59.5 ± 4.8% of saline control. S1 or S2 dorsal root stimulation at threshold intensity for inducing reflex twitching of the anal sphincter or toe significantly (P < 0.01) increased bladder capacity to 105.3 ± 9.0% and 134.8 ± 8.9% of saline control, respectively. Picrotoxin, a GABAA receptor antagonist administered i.v., blocked S1 inhibition at 0.3 mg/kg and blocked S2 inhibition at 1.0 mg/kg. Picrotoxin (0.4 mg, i.t.) did not alter the inhibition induced during S1 or S2 stimulation, but unmasked a significant (P < 0.05) poststimulation inhibition that persisted after termination of stimulation. Naloxone, an opioid receptor antagonist (0.3 mg, i.t.), significantly (P < 0.05) reduced prestimulation bladder capacity and removed the poststimulation inhibition. Strychnine, a glycine receptor antagonist (0.03–0.3 mg/kg, i.v.), significantly (P < 0.05) increased prestimulation bladder capacity but did not reduce sacral S1 or S2 inhibition. After strychnine (0.3 mg/kg, i.v.), picrotoxin (0.3 mg/kg, i.v.) further (P < 0.05) increased prestimulation bladder capacity and completely blocked both S1 and S2 inhibition. These results indicate that supraspinal GABAA receptors play an important role in sacral neuromodulation of bladder overactivity, whereas glycine receptors only play a minor role to facilitate the GABAA inhibitory mechanism. The poststimulation inhibition unmasked by blocking spinal GABAA receptors was mediated by an opioid mechanism.

Neurotransmitter Mechanisms Underlying Sacral Neuromodulation of Bladder Overactivity in Cats

To determine the role of opioid, β‐adrenergic, and metabotropic glutamate 5 receptors in sacral neuromodulation of bladder overactivity.

Sacral neuromodulation of nociceptive bladder overactivity in cats

To investigate the effects of electrical stimulation of sacral dorsal/ventral roots on irritation‐induced bladder overactivity, reveal possible different mechanisms under nociceptive bladder conditions, and establish a large animal model of sacral neuromodulation.

Clinical experience with temporary right ventricular mechanical circulatory support

Objectives This study sought to determine if indication for support affects the outcomes after temporary right ventricular mechanical circulatory support after postcardiotomy cardiogenic shock, cardiac transplant, or left ventricular assist device placement. Methods A retrospective review was performed on 80 patients receiving a right ventricular assist device. Data were collected from a prospectively maintained database. Kaplan–Meier survival analysis was performed to compare survival between groups. Multivariate regression analysis was performed to identify risk factors for failure to wean from support. Results The indication for support was postcardiotomy cardiogenic shock in 13 patients (16%), cardiac transplant in 25 patients (31%), and left ventricular assist device in 42 patients (53%). Median support time was 6 days. Device was successfully weaned in 6 postcardiotomy cardiogenic shock cases (46%), 21 cardiac transplant cases (84%), and 35 left ventricular assist device cases (83%). Survival was worse for patients with postcardiotomy cardiogenic shock compared with patients with a left ventricular assist device. Survival up to 3 months was better for patients who received immediate (n = 43) versus delayed (n = 37) support (79% vs 46%, P = .003). Weaning and survival remained static across implant era. Risk factor analysis identified postcardiotomy cardiogenic shock indication (odds ratio, 0.161; P = .007; confidence interval, 0.043‐0.600) as an independent negative predictor of weaning from mechanical support. Conclusions Temporary right ventricular mechanical support remains an effective treatment strategy after left ventricular assist device placement with immediate support resulting in superior short‐term survival. Caution should be applied in postcardiotomy cardiogenic shock when weaning and survival are poor. Overall survival outcomes have remained relatively static over time.

Safety and Surgical Outcomes of Same-day Anterior Urethroplasty

OBJECTIVE To evaluate the safety and feasibility of same-day anterior urethroplasty at our institution and define predictors of postoperative admission and surgical failure. METHODS We retrospectively reviewed the charts of 118 consecutive anterior urethroplasties performed at a tertiary care center. Data were analyzed to detect predictors of postoperative admission and urethroplasty failure. The 30-day complications and long-term outcomes were compared between same-day and admitted patients. RESULTS Ninety-two patients (78%) were discharged on the day of surgery. A penile stricture location compared with a bulbar stricture location (odds ratio: 13.4, P = .009) and having undergone more than 3 prior endoscopic stricture interventions (odds ratio: 10.2, P = .001) were significantly associated with postoperative admission. Patients with a ventral onlay approach were more likely to be discharged home (P = .03), whereas patients with combined repairs were more likely to be admitted (P = .04). Same-day urethroplasty did not increase 30-day postoperative complications, patient emergency room visits, unplanned clinic visits, or phone calls. Success rates did not differ between same-day (89%) and admitted (79%) cohorts, and no individual stricture characteristic was predictive of urethroplasty failure. CONCLUSION Same-day anterior urethroplasty is safe and feasible and could help increase utilization of urethroplasty for urethral stricture disease.

Lumbosacral spinal segmental contributions to tibial and pudendal neuromodulation of bladder overactivity in cats

To determine the spinal segmental afferent contributions to tibial and pudendal inhibition of bladder overactivity.

Sex difference in the contribution of GABAB receptors to tibial neuromodulation of bladder overactivity in cats

This study investigated the role of γ-aminobutyric acid subtype B (GABAB) receptors in tibial and pudendal neuromodulation of bladder overactivity induced by intravesical administration of dilute (0.5%) acetic acid (AA) in α-chloralose-anesthetized cats. To inhibit bladder overactivity, tibial or pudendal nerve stimulation (TNS or PNS) was applied at 5 Hz and two or four times threshold (T) intensity for inducing toe or anal sphincter twitch. TNS at 2T or 4T intensity significantly (P < 0.05) increased the bladder capacity to 173.8 ± 16.2 or 198.5 ± 24.1%, respectively, of control capacity. Meanwhile, PNS at 2T or 4T intensity significantly (P < 0.05) increased the bladder capacity to 217 ± 18.8 and 221.3 ± 22.3% of control capacity, respectively. CGP52432 (a GABAB receptor antagonist) at intravenous dosages of 0.1-1 mg/kg completely removed the TNS inhibition in female cats but had no effect in male cats. CGP52432 administered intravenously also had no effect on control bladder capacity or the pudendal inhibition of bladder overactivity. These results reveal a sex difference in the role of GABAB receptors in tibial neuromodulation of bladder overactivity in cats and that GABAB receptors are not involved in either pudendal neuromodulation or irritation-induced bladder overactivity.

Trends in Urologic Indications for Pediatric Renal Transplantation Over a 27 Year Period- UNOS Database

OBJECTIVE To elucidate the trends in urologic causes for renal transplant in the pediatric population using a national database. Little is known about the specific pediatric urologic conditions and resultant trends that precede renal transplantation. MATERIAL AND METHODS We reviewed the United Network for Organ Sharing (UNOS) database for pediatric patients (<18 years old) who underwent renal transplantation from January 1988 to September 2015. We included those patients who received a renal transplant because of a urologic condition. RESULTS Over 27 years, 7291 of 20,213 children (36%) underwent renal transplant secondary to a urologic condition. The 2 most common indications were hypoplasia/dysplasia/dysgenesis/agenesis (HDDA, 35.1%) and congenital obstructive uropathy (COU, 25.7%). The incidence of COU has increased from 18% to 30%, and the incidence of Wilms tumor has remained relatively consistent at 1.8% per year. In addition, 68% of all urologic renal transplants were performed in men compared with women. However, a higher percentage of women required transplantation because of Wilms tumor (3.1% vs 1.2%) and chronic pyelonephritis (17.6% vs 7.9%). Overall, the majority of patients (61.5%) who underwent renal transplantation were white, 18.8% Hispanic, and 15.3% black. CONCLUSION HDDA and COU consistently have been the most common urologic indications for renal transplantation. Both are the leading causes in men, whereas HDDA and chronic pyelonephritis are predominant in women. Higher rate of renal transplant during the ages of 11-17 years is suggestive of increased burden on poorly functioning kidneys during times of adolescent growth.

Optimal Length of Follow-up for the Detection of Unsuccessful Pediatric Pyeloplasty: A Single-Center Experience

Objectives To assess the optimal length of follow-up for patients undergoing both open and minimally invasive pyeloplasties to ensure prompt detection of a recurrent obstruction. There are no standard guidelines on ideal follow-up and imaging post-pediatric pyeloplasty currently. Methods A retrospective chart review identified 264 patients (<18 years old) who underwent pyeloplasty for ureteropelvic junction obstruction between April 2002 and December 2014. Ultrasound was obtained every 3–4 months for the first year following pyeloplasty and thereafter at discretion of treating physician. Patient characteristics including symptoms and imaging were reviewed. Results Of the 264 patients, 72% were male with mean age of 51 months and follow-up of 26.8 months. Approximately 73% followed up to 3 years. Fourteen patients (5.3%) had a recurrent obstruction. Among the failures, 85% were diagnosed and underwent successful redo pyeloplasty within 3 years. Six infants had a recurrence (43% of all unsuccessful surgeries) and were diagnosed within 3 years of the initial surgery. Patients undergoing a minimally invasive procedure were less likely to be followed for more than 3 years compared to an open procedure (p < 0.001). Patients with severe hydronephrosis preoperatively were followed longer (p = 0.031). Age at surgery and type of surgical approach (p < 0.01) were significant predictors of length of follow-up in a negative binomial regression. Conclusion Based on the results, a minimum of 3 years of follow-up is necessary to detect the majority of recurrent obstructions. Those patients who have higher than average lengths of follow-up tend to be younger and/or underwent an open surgical approach.