Serge Carrier

Effect of simulated birth trauma on the urinary continence mechanism in the rat.

OBJECTIVES To examine the effect of simulated birth injury in an animal model as part of a study on the pathogenesis of stress urinary incontinence (SUI) and the urinary continence mechanism. METHODS A balloon was inflated in the vaginas of rats for 4 hours to simulate prolonged labor. The effect on the continence mechanism was assessed by functional, anatomic, biochemical, and histologic examinations. The functional test consisted of placing chili powder or a clipped whisker into the rats nostrils to induce sneezing. Anatomic measurement of the genital hiatus was performed with a caliper. Serum creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) were measured to examine the value of muscle injury in predicting incontinence. c-Fos immunostaining in the spinal cord was used as a marker of nerve injury. These data were then correlated with histopathologic examination of the urethra and pelvic floor tissues. RESULTS Four weeks after simulated birth injury, SUI was noted in 19 of 48 experimental rats. The genital hiatus was significantly wider in incontinent rats. The serum CPK and LDH levels were markedly elevated, but no difference was noted between the continent and incontinent rats. All experimental rats showed many c-Fos immunostaining neurons in the L6 to S1 spinal cord segments, but none was seen in control rats. Histologic study revealed a marked decrease of ganglion cells in the neural plexuses posterolateral to the vagina in experimental rats. After 4 weeks, muscle necrosis and degeneration, irregular shape and size of muscle fibers, and a change in the type I/II ratio were prominent features in the levator ani. In the urethra, we noted a significant decline in urethral wall musculature (both smooth and striated) in incontinent rats. CONCLUSIONS In this novel rat model, simulated birth injury resulted in SUI in a portion of the animals. Pathologic changes in the urethra, pelvic ganglia, and levator muscles seem to be the contributing factors to SUI.

REGENERATION OF NITRIC OXIDE SYNTHASE-CONTAINING NERVES AFTER CAVERNOUS NERVE NEUROTOMY IN THE RAT

In patients who recover erectile function after radical prostatectomy (with preservation of at least 1 neurovascular bundle), a recovery time of 6 to 18 months is not uncommon. As this is also the usual time required for regeneration of spinal nerves, we believe that regeneration of cavernous nerves, partially damaged inadvertently, may be responsible. In a rat model, we examined the long-term effect of unilateral and bilateral cavernous nerve transection on the nonadrenergic/noncholinergic (NANC) nervous system and erectile function. In 31 rats, nitric oxide synthase (NOS), the enzyme that catalyzes nitric oxide production, was identified in penile nerve fibers from a mid-shaft segment with nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase staining and antibody to neuronal NOS. Animals were divided into three groups: 5 rats underwent pelvic exploration without transection of cavernous nerves (sham group); 13 rats underwent unilateral neurotomy of a 5-mm. segment of the cavernous nerve; and 13 rats underwent bilateral neurotomy. After bilateral ablation, the NOS-positive nerve fibers were significantly decreased at 3 weeks and remained so at 6 months; no erectile response could be elicited by pelvic nerve stimulation. After unilateral ablation, the NOS-positive nerve fibers were similarly decreased on the side of the neurotomy at 3 weeks, but by 6 months the number had increased significantly and approximated the level on the contralateral side. Furthermore, electrostimulation of the intact side induced a greater intracavernous pressure response at 6 months than at 3 weeks (N.B. the rat has an incomplete septum). Fibers positive for NOS were also identified in the dorsal nerve. The staining pattern diminished as rapidly and significantly on the side of neurotomy as in tissue from the corpus cavernosum. However, regeneration was not seen. To our knowledge, this is the first demonstration of regeneration of NOS-containing nerves after cavernous nerve neurotomy. Our findings support the reports by others that unilateral nerve-sparing is sufficient to preserve erectile function.

AGE DECREASES NITRIC OXIDE SYNTHASE-CONTAINING NERVE FIBERS IN THE RAT PENIS

PURPOSE To study the effect of aging on erectile function in a rat model. MATERIALS AND METHODS We investigated: 1) the number and distribution of nerve fibers within the corpus cavernosum and dorsal nerve containing vasoactive intestinal polypeptide (VIP) and nitric oxide synthase (NOS); and 2) the erectile response to apomorphine (a central dopamine receptor agonist), electrostimulation of the cavernous nerve, and intracorporeal papaverine injection. RESULTS The number of NOS-containing nerve fibers was significantly less in the old rats (24 months) than in the young (2.5 months) and intermediate (8.5 months)-aged (63.3 +/- 3.35 vs. 135.1 +/- 10.88 [p < or = 0.0002] and 127.8 +/- 11.65 [p < or = 0.0002]). The number of erections induced by apomorphine was significantly less in the old rats than in the young (1.0 +/- 3.1 vs. 3.6 +/- 0.26; p < 0.002). With electrostimulation, the latency period before the onset of the intracavernous pressure rise was noted to increase with age (2.3 +/- 0.24 sec. for the young vs. 6.77 +/- 0.98 sec. for the old, p < or = 0.0001). The maximal intracavernous pressure after intracavernous papaverine injection decreased with age. CONCLUSION The erectile mechanism appears to remain intact as rats age, but the response to central and peripheral stimulation decreases. The reduction in NOS-containing nerve fibers might account for these observations.

Is colchicine effective in Peyronie'sdisease? A pilot study

OBJECTIVES The treatment of Peyronies disease with oral or topical agents has not been entirely satisfactory. In this pilot study, we hypothesized that colchicine, known to induce collagenase activity and decrease collagen synthesis, might be an ideal agent in the treatment of Peyronies disease. METHODS Colchicine was administered orally for 3 to 5 months to a group of 24 previously untreated patients with Peyronies disease. RESULTS Peyronies plaque decreased or disappeared in 12 of the 24 patients, 7 of 9 patients with painful erections reported significant relief, and penile curvature was improved in 7 of 19 cases. Erectile status, narrowing of the penis, and accompanying Dupuytrens contracture did not change in any of the cases. CONCLUSIONS Although this pilot study shows some promising results of the use of colchicine in the treatment of Peyronies disease, the ultimate usefulness of this agent will be determined only by a prospective double-blind clinical study.

Effect of testosterone on the number of NADPH diaphorase-stained nerve fibers in the rat corpus cavernosum and dorsal nerve.

OBJECTIVES To elucidate the effect of testosterone on penile nerve supply. METHODS Three groups of 10 rats each were assessed; two groups were castrated and the third underwent a sham operation (control). After castration, one group received subcutaneous injection of testosterone while the others received sesame oil. At 8 weeks, the rats underwent a functional analysis. The evaluation included a subcutaneous injection with apomorphine to study centrally mediated erection, and cavernous nerve electrostimulation and papaverine injection to study peripherally mediated erection. At death, a penile midshaft specimen was taken for nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase staining. RESULTS In the apomorphine study, castrated rats had no erections, but the erectile function of those receiving testosterone was restored to the level of the controls. The mean numbers of NADPH-diaphorase-stained nerve fibers in the copora cavernosa and both dorsal nerves of castrated rats, at 165.8 +/- 20.0 and 271.3 +/- 21.1, respectively, were significantly lower than those of the controls, at 271.7 +/- 14.6 and 471.2 +/- 27.6, respectively. Those of the testosterone replacement group, at 290.7 +/- 10.1 and 500.7 +/- 23.9, respectively, recovered to the control level. The intracavernosal pressure decreased significantly in the absence of testosterone, both after electrostimulation and intracavernosal papaverine injection, and recovered to the control level after testosterone replacement. CONCLUSIONS Our results indicate that testosterone acts on the nervous system to mediate erection. When it is absent, there may be downregulation of both the production and activity of nitric oxide (NO), thereby decreasing the response to peripheral stimulation via the NO pathway. Testosterone replacement may upregulate NO activity to the control level.

Pathophysiology of erectile dysfunction

During the past decade, our knowledge of the hemodynamics, functional anatomy, neurophysiology, and neuropharmacology of erectile function has evolved substantially. The change of smooth muscle tone has emerged as a key factor in erection and detumescence. However, future studies are needed to elucidate the cellular and molecular basis of erectile physiology. With insight into normal physiology we will understand the pathologic process and be able to treat it.

ORIGINAL RESEARCH—PHYSIOLOGYORIGINAL RESEARCH—PHYSIOLOGY: Thermography as a Physiological Measure of Sexual Arousal in Both Men and Women

INTRODUCTION Current physiological measures of sexual arousal are intrusive, hard to compare between genders, and quantitatively problematic. AIM To investigate thermal imaging technology as a means of solving these problems. METHODS Twenty-eight healthy men and 30 healthy women viewed a neutral film clip, after which they were randomly assigned to view one of three other video conditions: (i) neutral (N = 19); (ii) humor (N = 19); and (iii) sexually explicit (N = 20). MAIN OUTCOME MEASURES Genital and thigh temperatures were continuously recorded using a TSA ImagIR camera. Subjective measures of sexual arousal, humor, and relaxation were assessed using Likert-style questions prior to showing the baseline video and following each film. RESULTS Statistical (Tukey HSD) post-hoc comparisons (P < 0.05) demonstrated that both men and women viewing the sexually arousing video had significantly greater genital temperature (mean = 33.89 degrees C, SD = 1.00) than those in the humor (mean = 32.09 degrees C, SD = 0.93) or neutral (mean = 32.13 degrees C, SD = 1.24) conditions. Men and women in the erotic condition did not differ from each other in time to peak genital temperature (men mean = 664.6 seconds, SD = 164.99; women mean = 743 seconds, SD = 137.87). Furthermore, genital temperature was significantly and highly correlated with subjective ratings of sexual arousal (range r = 0.51-0.68, P < 0.001). There were no significant differences in thigh temperature between groups. CONCLUSION Thermal imaging is a promising technology for the assessment of physiological sexual arousal in both men and women.

Diabetes and male sexual function

Diabetes mellitus (DM) is the most common cause of erectile dysfunction (ED). Up to 28% of men complaining of ED have DM as the primary causative factor. DM should be considered in all patients presenting with ED. Known diabetic men should be encouraged to have excellent control of their DM to avoid not only the chronic complications of DM but also its acute effects, especially the effect of hyperglycemia on erectile function. The physiological impact of diabetes on sexual function in men is reviewed.

Duplex Ultrasonography After Prostaglandin E1 Injection of the Clitoris in a Case of Hyperreactio Luteinalis

We report an unusual case of persistent postpartum clitorimegaly due to ovarian hyperreactio luteinalis. Duplex ultrasonography of the clitoris after intracorporeal injection of prostaglandin E1 revealed marked clitoral erection and increased arterial flow, as in the penis.

Assessment of photoselective vaporization of prostate skills during Urology Objective Structured Clinical Examinations (OSCE)

INTRODUCTION We evaluated the use of the GreenLight Simulator (GL-SIM) (American Medical Systems, Guelph, ON) in the skill assessment of postgraduate trainees (PGTs) in photoselective vaporization of the prostate (PVP). We also sought to determine whether previous PVP experience or GL-SIM practice improved performance. METHODS PGTs in postgraduate years (PGY-3 to PGY-5) from all 4 Quebec urology training programs were recruited during 2 annual Objective Structured Clinical Examinations (OSCEs). During a 20-minute OSCE station, PGTs were asked to perform 2 exercises: (1) identification of endoscopic landmarks and (2) a PVP of a 30-g normal prostate. Grams vaporized, global scores, and number of correct anatomical landmarks were recorded and correlated with PGY level, practice on the GL-SIM, and previous PVP experience. RESULTS In total, 25 PGTs were recruited at each OSCE, with 13 PGTs participating in both OSCEs. When comparing scores from the first and second OSCEs, there was a significant improvement in the number of grams vaporized (2.9 vs. 4.3 g; p = 0.003) and global score (100 vs. 165; p = 0.03). There was good correlation between the number of previously performed PVPs and the global score (r = 0.4, p = 0.04). Similarly, PGTs with previous practice on the GL-SIM had significantly higher global score (100.6 vs. 162.6; p = 0.04) and grams vaporized (3.1 vs. 4.1 g; p = 0.04) when compared with those who did not practice on GL-SIM. Furthermore, there were significantly more competent PGTs among those who had previously practiced on the GL-SIM (32.7% vs. 10.2%; p = 0.009). PGY level did not significantly affect grams vaporized or global score (p > 0.05). CONCLUSION Performance on the GL-SIM at OSCEs significantly correlated with previous practice on the GL-SIM and previous PVP experience rather than PGY level. Furthermore, there were significantly more competent PGTs among those who had previously practiced on the GL-SIM.