Effect of rectal distension on vesical motor activity in humans: the identification of the recto-vesicourethral reflex

OBJECTIVE: Rectal lesions have an effect on the urinary bladder and its sphincters. Patients with constipation sometimes complain of difficult micturition or of retention. Urinary retention may also occur after anorectal operations. We investigated the hypothesis that rectal distension affects vesical dilatation through a reflex action. METHODS: The study comprised 22 healthy volunteers (14 men, 8 women, age 42.3 +/- 10.3 SD years). The rectum was distended by rectal balloon inflated with air in increments of 50 mL. The vesical and posterior urethral pressures were recorded before and after individual anesthetization of the rectum, bladder, and posterior urethra. RESULTS: Fifty-milliliter rectal distension effected no vesicourethral pressure response (P > 0.05). At 100 and up to 300-mL distension, the vesical pressure decreased (P < 0.05), while the urethral pressure increased (P < 0.05). The response showed no significant difference upon increase of the distending volume. The mean latency was 16.8 +/- 2.4 milliseconds. Vesicourethral pressure did not respond to rectal distension when the bladder, urethra, or rectum was individually anesthetized. CONCLUSIONS: Rectal distension seems to induce diminished vesical, but increased urethral sphincter tone, an effect that is presumably mediated through a reflex that we call the "recto-vesicourethral reflex." This reflex is apparently evoked at defecation to abort simultaneous micturition. The clinical significance of the reflex needs to be established.     

Role of sacral ligament clamp in the pudendal neuropathy (pudendal canal syndrome): results of clamp release

Pudendal canal syndrome (PCS) is treated by pudendal canal (PC) decompression. We studied the hypothesis that failure of PCD to relieve anal and perianal pain could result from compression of the pudendal nerve (PN) not only in the PC but also in the sacral ligament clamp (SLC), i.e., in the space between sacrotuberous and sacrospinous ligaments. SLC release was performed in 21 patients with proctalgia who had not improved after PCD. PN terminal motor latency was higher than normal. The SLC release operation comprised entering the ischiorectal fossa through a para-anal incision, identifying the PN, and division of sacrospinous ligament. Treatment was successful in 17 patients and failed in 4. The former showed pain disappearance and improvement in fecal incontinence, perianal sensation, and anal reflex. Clinical manifestations and investigative results improved after SLC release in 80.9% of the cases. We assume that these results denote traumatization of the PN not only in the PC but also in the SLC.     

Study of the cremasteric muscle during erection

Background Mechanism of testicular elevation during erection is not known. We investigated the hypothesis that erection evokes reflex cremasteric muscle (CM) contraction which effects testicular elevation.Methods Electromyographic (EMG) response of CM to erection was recorded in 26 healthy volunteers (age 36.7 ± 6.8 SD years). Erection was induced by intracavernosal injection of alprostadil. CM response was tested before and after individual glans penis (GP) and CM anesthetization.Results The CM exhibited resting electric activity of mean amplitude of 74.8 ± 6.3 μV which, on erection, increased to 486.6 ± 36.8 μV (P < 0.001). Response was momentary. Anesthetization of erect GP did not effect increase of CM EMG activity, while bland gel did. Anesthetized CM did not respond to GC erection while saline infiltrated did.Conclusions The CM appears to contract during erection through a reflex which we call ‘peno-cremasteric reflex’. CM contraction assumingly elevates testicle and support cord veins; it may effect testicular compression, thus expressing its secretions into vas deferens.     

Study of the duodenal contractile activity during antral contractions

AIM: To investigate the hypothesis that duodenal bulb (DB) inhibition on pyloric antrum (PA) contraction is reflex. METHODS: Balloon (condom)-tipped tube was introduced into 1st duodenum (DD) and a manometric tube into each of PA and DD. Duodenal and antral pressure response to duodenal and then PA balloon distension with saline was recorded. These tests were repeated after separate anesthetization of DD and PA. RESULTS: Two and 4 mL of 1st DD balloon distension produced no pressure changes in DD or PA (10.7 ± 1.2 vs 9.8 ± 1.2, 11.2 ± 1.2 vs 11.3 ± 1.2 on H2O respectively, P > 0.05). Six mL distension effected 1st DD pressure rise (30.6 ± 3.4 cm H2O, P < 0.01) and PA pressure decrease (6.2 ± 1.4 cm H2O, P < 0.05); no response in 2nd, 3rd and 4th DD. There was no difference between 6, 8, and 10 mL distensions. Ten mL PA distension produced no PA or 1st DD pressure changes (P > 0.05). Twenty mL distension increased PA pressure (92.4 ± 10.7 cm H2O, P < 0.01) and decreased 1st DD pressure (1.6 ± 0.3 cm H2O, P < 0.01); 30, 40, and 50 mL distension produced the same effect as the 20 mL distension (P > 0.05). PA or DD distension after separate anesthetization produced no significant pressure changes in PA or DD. CONCLUSION: Large volume DD distension produced DD pressure rise denoting DD contraction and PA pressure decline denoting PA relaxation. PA relaxation upon DD contraction is postulated to be mediated through a reflex which we call duodeno-antral reflex. Meanwhile, PA distension effected DD relaxation which we suggest to be reflex and termed antro-duodenal reflex. It is suggested that these 2 reflexes, could act as investigative tools indiagnosis of gastroduodenal motility disorders.     

Vesical pacing in patients with overactive bladder: technique and results

OBJECTIVES: A recent study has demonstrated that the electric activity of the overactive bladder (OAB) is 'dysrhythmic'. The cause was attributed to a disordered vesical pacemaker which discharges these waves. In a subsequent study, the dysrhythmic waves have been 'normalized' by vesical pacing and the optimal parameters which are required to achieve normalization have been defined. We investigated the hypothesis that vesical pacing of the OAB might improve not only the vesical electric activity but also the symptoms. METHODS: Vesical pacing was used in 9 patients (age 39.2 +/- 10.3; 5 women, 4 men) with OAB. Under anesthesia, the pacemaker was implanted in an inguinal subcutaneous pocket and connected to 2 pacing electrodes implanted into the vesical vault. The normalization of the waves was tested by 2 recording electrodes which were temporarily applied to the vesical wall and removed post-testing. The pacemaker was then programmed for home pacing to be activated at given times. RESULTS: Vesical pacing effected normalization of the dysrhythmic electric waves with disappearance of the OAB symptoms in 7 patients and failed in 2. Vesical pacing was abandoned in 3/7 patients after a few months following the spontaneous disappearance of the symptoms. CONCLUSIONS: Vesical pacing has normalized the dysrhythmic electric activity and suppressed the symptoms of the OAB in 77.7% of patients. The pacemaker was removed in 5 patients: 2 failures and 3 after spontaneous waves normalization. No complications were encountered. Vesical pacing is suggested as a treatment for OAB when commonly used therapeutic modalities have failed.     

Do vesical and voided urine have identical compositions?

OBJECTIVE: In view of the concept that the urothelium is a functioning epithelium, we investigated the hypothesis that the composition of urine is modified as it passes through the urethra from the urinary bladder to the exterior. MATERIAL AND METHODS: The study was performed in 22 healthy volunteers (13 males, 9 females; mean age 44.6+/-6.2 years). Vesical and voided urine were collected separately; pH was determined using a pH electrode, osmolality by means of micro-osmometry and electrolytes (Na, K) using flame photometry. RESULTS: Voided urine showed significant increases in pH, osmolality and Na and K concentrations compared to urine contained in the bladder (p < 0.05 for each). Gender and age differences were not significant. CONCLUSIONS: Vesical urine undergoes changes in some of its components during its passage through the urethra. These findings presumably indicate that the urethral urothelium is a functioning epithelium and also that voided and vesical urine are not identical. The study raises the question to what extent is the analysis of voided urine representative of that of vesical urine?     

Mycophenolate mofetil without antibody induction in cadaver vs. living donor pediatric renal transplantation

Mycophenolate mofetil (MMF) is a new immunosuppressive agent that blocks de novo purine synthesis in T and B lymphocytes via a potent selective inhibition of inosine monophosphate dehydrogenase. MMF has been shown to significantly reduce the incidence of acute rejection in both adult and pediatric renal transplantation. The impact of MMF on routine antibody induction therapy in pediatric renal transplantation has not been defined. Remarkably, a recent North American Pediatric Transplant Cooperative Study concluded that T-cell antibody induction therapy was deleterious for patients who received MMF. Our study examines the use of MMF in an evolving immunosuppressive strategy to avoid antibody induction in both living (LD) and cadaver (CAD) donor pediatric renal transplantation. We retrospectively analyzed the records of 43 pediatric renal transplants that received MMF-based triple therapy without antibody induction therapy between November 1996 and April 2000. We compared CAD (n = 17) with LD (n = 26). The two groups were similar demographically except that CAD had significantly younger donors than LD, 26.1 +/- 13.7 vs. 36.2 +/- 9.2 yr (p = 0.006). All the patients received MMF at 600 mg/m2/b.i.d. (maximum dose of 2 g/d) and prednisone with cyclosporine (86%) or tacrolimus (14%). Mean follow-up was >36 months for each group. Acute rejection rate at 6 months was 11.8% (CAD) vs. 15.4% (LD) (p = 0.999) and at 1 yr was 23.5% (CAD) vs. 26.9% (LD) (p = 0.999). Mean estimated glomerular filtration rate (ml/min/1.73 m2) at 6 months was 73.3 +/- 15.3 (CAD) vs. 87.6 +/- 24.2 (LD) (p = 0.068). Patient survival at 1, 2, and 3 yr was 100, 100, and 100% for CAD vs. 100, 96, and 96% for LD, respectively. Graft survival at 1, 2, and 3 yr was 100, 100, and 94% for CAD vs. 96, 88, and 71% for LD, respectively. Graft loss in CAD was because of chronic rejection (n = 2) while in LD it was because of non-compliance (n = 6), post-transplant lymphoproliferative disorder (n = 1), and sepsis (n = 1). In conclusion, MMF without antibody induction in both CAD and LD pediatric renal transplantation provides statistically similar and effective prophylaxis against acute rejection at 6 months and 1 yr post-transplant. The short-term patient and graft survival rates are excellent, however, non-compliance remains a serious challenge to long-term graft survival. Additional controlled studies are needed to define the role of MMF without antibody induction therapy in pediatric renal transplantation.