Tunica albuginea acellular matrix graft for penile reconstruction in the rabbit: a model for treating Peyronie's disease

OBJECTIVE

To evaluate the use of an acellular matrix graft of the tunica albuginea for functional penile reconstruction in severe cases of Peyronie's disease.

MATERIALS AND METHODS

In 18 rabbits, an acellular matrix graft of the tunica albuginea was used to cover a 4 x 8 mm tunical defect, and six animals each were killed 1, 3 and 6 months later; four unoperated animals served as histological controls. Before death an erection was induced by papaverine, with the quality classified on a scale of 0-5, and cavernosography performed. After death the penis was prepared for histological study, and the cell number, collagen and elastic fibre content evaluated in the regenerated matrix, and in control specimens and four unimplanted matrices.

RESULTS

Of 18 experimental animals, 11 had normal erections before death, four had slight penile deviation and three developed no erection. Failure was caused by severe postoperative haematoma, resulting in scar tissue. There was no graft rejection. Histologically there was no difference between natural and regenerated tunica. The collagen content and cell number were not significantly different in regenerated and control samples. There were significantly fewer elastic fibres in the unimplanted grafts and the 1-month group, but in later samples this difference was no longer evident.

CONCLUSION

The homologous acellular matrix graft of the tunica albuginea warrants further evaluation as an alternative treatment in Peyronie's disease, despite some postoperative failures. The advantage of this orthotopic biomaterial is its rapid integration, with no rejection.

Heterologous acellular matrix graft for reconstruction of the rabbit urethra: histological and functional evaluation

PURPOSE

In a rabbit model we evaluated urethral replacement by a free heterologous dog acellular matrix graft and compared these results with those of a homologous graft with the exclusion of antigenicity as a major goal.

MATERIALS AND METHODS

In 14 male New Zealand rabbits a 0.8 to 1.1 cm. segment of urethra was resected and replaced with a tubular acellular 1.0 to 1.5 cm. (mean 1.3) urethral matrix graft placed on an 8Fr feeding tube. Seven animals received a rabbit graft, 7 received a canine graft and 3 untreated rabbits served as controls. All animals underwent urethral pressure profile determination and retrograde urethrography before 8 and 6 were sacrificed at 6 and 8 months, respectively. Grafted and normal specimens were evaluated by histological testing.

RESULTS

In all animals the acellular matrix graft remained in its original position. Histological examination showed complete epithelialization and progressive vessel infiltration. At 6 months more than a third of the homologous grafts had smooth muscle bundles but the heterologous grafts had only poorly disseminated smooth muscle. Picrosirius red stain demonstrated a shift in the ratio of collagen types I-to-III with an increase in type III in the processed homologous and heterologous matrices that did not change significantly postoperatively. At 8 months the urethral pressure profile detected no difference in control and matrix grafted animals, and urethrography did not readily differentiate host from implant.

CONCLUSIONS

In the heterologous matrix all tissue components were present after 6 months with no signs of rejection and even gradual improvement with time. However, regenerated smooth muscle did not equal that in normal rabbit urethra and it was not well oriented. Even after 8 months only a few disseminated smooth muscle cells were evident. Most alpha-actin positive cells were surrounding the vessels. Although function was normal, the alteration in the collagen ratio effected by matrix production indicated that the matrix collagen appeared not to have been replaced by host collagen. The increase in collagen type III may explain the lack of stricture in the grafted animals on normal retrourethrography.

Time dependent smooth muscle regeneration and maturation in a bladder acellular matrix graft: histological studies and in vivo functional evaluation

PURPOSE

We evaluated the time dependence of smooth muscle regeneration and restoration of in vivo functional properties in bladder augmented with a bladder acellular matrix graft.

MATERIALS AND METHODS

A total of 45 Sprague-Dawley rats underwent augmentation cystoplasty with a bladder acellular matrix graft. Two rats each were sacrificed at various intervals within the first 21 days and 6 each were sacrificed at 4, 8 and 12 weeks. This second group underwent preoperative and postoperative assessment of bladder function, including cystometry, electrostimulation and stimulation with ice water, potassium and carbachol, as well as labeling of the bladder wall by the injection of fluorescent microspheres. After sacrifice slides of the bladders prepared for hematoxylin and eosin, trichrome, KI67, vimentin, desmin, smooth muscle specific alpha-actin and fluorescent microspheres were evaluated.

RESULTS

Within 2 weeks the number of cells in the matrix as well as the proliferation index increased rapidly and then decreased gradually. Erythrocytes and inflammatory cells were found in the matrix within 2 to 4 days, followed by fibroblasts. A bladder host-to-matrix shift was evident by the appearance of microspheres in the matrix. Cell marker expression indicated the early appearance of vimentin and alpha-actin within the first 10 days. Distinct desmin expression was observed later, when the first smooth muscle cells were recognized. Functional evaluation revealed restored bladder function at 12 weeks.

CONCLUSIONS

The time dependent increase of muscle cell markers during smooth muscle cell regeneration in a bladder acellular matrix graft is concordant with the progressive restoration of bladder function. These results may support the bladder acellular matrix graft concept for clinical application.

Bladder acellular matrix graft in rats: its neurophysiologic properties and mRNA expression of growth factors TGF-alpha and TGF-beta

To assess the neurophysiologic properties and molecular mechanisms of the bladder acellular matrix graft (BAMG), we performed cystometric and neurophysiologic studies in male Sprague-Dawley rats (n = 46) at varying intervals. The animals were assigned to 3 groups: 1) normal, 2) partial cystectomy (>50%), and 3) partial cystectomy (>50%) and grafting with a BAMG of equal size. Additionally, matrix-grafted and host bladders were processed for analysis of mRNA expression of transforming growth factor (TGF)-alpha, TGF-beta1, TGF-beta2, and TGF-beta3 by reverse transcriptase polymerase chain reaction. Matrix-grafted bladders showed a significantly higher bladder capacity at 3 and 6 weeks and 4 months than those with partial cystectomy alone, and a significantly higher bladder capacity at 4 months than in normal controls (P < or = 0.01). Residual urine volume was significantly increased at 4 months. Electrostimulation of the pelvic nerve provoked generalized bladder contractions, a response that was reduced by atropine and hexamethonium. Variable induction of TGF-alpha, TGF-beta1, TGF-beta2, and TGF-beta3 gene transcription was evident in the BAMG, with prominent mRNA expression of TGF-alpha and TGF-beta1 6 months after surgery. These cystometric results and detrusor responses to stimulation provide further evidence that graft components do not interfere with host components. Matrix-grafted rat bladders generate, although not increased over time, adequate intravesical pressure responses to produce sustained voiding. Gene expression of different growth factors may be significant in understanding their role in the development and differentiation of the BAMG for partial bladder replacement.

Homologous acellular matrix graft for urethral reconstruction in the rabbit: histological and functional evaluation

OBJECTIVE

To evaluate urethral replacement by a free homologous graft of acellular urethral matrix in a rabbit model.

MATERIALS AND METHODS

In 30 male New Zealand rabbits, a 0.8 to 1.1 cm. segment of the urethra was resected, replaced with an acellular matrix graft of 1.0 to 1.5 cm. (mean 1.3 cm.), and placed on an 8F feeding tube. Additionally 4 animals underwent sham operation. At varying intervals before sacrifice (from 10 days to 8 months), the animals underwent urodynamic evaluation and retrograde urethrography (for which 4 untreated rabbits served as control). The grafted specimens were prepared for evaluation histologically and by reverse-transcription polymerase chain reaction (RT-PCR).

RESULTS

In all animals, the acellular matrix graft remained in its original position. Histological examination showed complete epithelialization and progressive vessel infiltration. At 3 months, smooth muscle bundles were first observed infiltrating the matrix at the end-to-end anastomosis; after 6 months, the smooth muscle bundles had grown into one-third of the matrix. Urodynamics did not detect any difference between the control and matrix-grafted animals in bladder volume, leak-point pressure and residual volume. RT-PCR detected an increase in IGF mRNA in the graft between week 3 and month 6 and in HB-EGF mRNA after day 10 through month 3. TGF-alpha mRNA was not detected; TGF-beta mRNA was unchanged from normal urethral tissue. By 8 months, the host and implant could not be differentiated by urethrography.

CONCLUSION

The acellular urethral matrix allows single-stage urethral reconstruction. All tissue components were seen in the grafted matrix after 3 months, with further improvement over time; however, the smooth muscle in the matrix was less than in normal rabbit urethra and was not well oriented. RT-PCR revealed the importance of time-dependent growth factor influences during regeneration.

Homologous bladder augmentation in dog with the bladder acellular matrix graft

OBJECTIVE

To determine the functional potential and antigenicity of the homologous bladder acellular matrix graft (BAMG) in a dog model.

MATERIALS AND METHODS

Seven mongrel dogs underwent partial cystectomy (20-50%) and grafting with an equal-sized BAMG; two control animals underwent partial cystectomy (40%) only. The dogs were killed after 30 (one), 120 (one) and 210 days (five dogs). Blood samples were obtained before and at 1, 2, 4, 7, 14, 30, 90 and 210 days after surgery. The dogs underwent cystography, intravenous pyelography and ultrasonography before and after surgery, and on the day they were killed, with cystoscopy carried out just before death. The grafted tissue was assessed using routine and immunohistochemical techniques.

RESULTS

All the dogs survived surgery; a complete blood cell count, chemical panel and white blood cell count showed no significant difference between the experimental and control animals. Cystography, cystoscopy and ultrasonography revealed no pathological changes in the upper urinary tract. After 7 months, the mean bladder capacity in the augmented dogs was significantly higher (P = 0.035) than in the controls (264 vs 172 mL). Histological evaluation showed an invasion of all bladder wall components during the first month; at 7 months, the morphological examination showed essentially complete regeneration.

CONCLUSION

In this dog model, the potential of the BAMG as a bladder augmentation graft was confirmed, having minimal antigenicity with maximal acceptance. The reconstructed bladder matched the morphological and functional properties of the normal bladder.

Organ-specific acellular matrix for reconstruction of the urinary tract

In urology, replacement of organs or organ segments has proved problematic. Current techniques do not replicate complete organ function, and they cause well-known complications. With the acellular organ-specific matrix we have found a way to regenerate tissue components seen in the normal lower urinary tract. The time required for regeneration depends on the matrix size and function. The matrix is covered by urothelium migrating from the host, after which neovascularization occurs, followed by formation of smooth-muscle cells and nerves. In our studies, normal muscle lining and nerves providing functional tissue were demonstrable and no sign of antigenicity was evident, even after heterologous grafting. The regenerated rat bladder was evaluated by organ bath as well as by in vivo functional tests and demonstrated properties and functions similar to those of host tissue. Besides our obtaining encouraging results in the rat bladder, we also studied the organ-specific acellular matrix in other species (dog and rabbit) and other organ segments (ureter and urethra).

Long-term results of colpocystourethropexy for persistent or recurrent stress urinary incontinence

PURPOSE

We review the long-term outcome of colpocystourethropexy for persistent or recurrent stress urinary incontinence after suspension procedure failure.

MATERIALS AND METHODS

Medical records and preoperative studies were reviewed of 60 patients (mean age 60.8 years) who had undergone colpocystourethropexy after at least 1 suspension procedure (range 1 to 8, mean 2.7). Patient responses to a standardized questionnaire regarding overall health, degree of satisfaction with colpocystourethropexy, presence or absence of leakage, and pattern and degree of leakage were elicited by telephone or mail and compared with preoperative status. Results were graded according to the degree of satisfaction and number of pads used daily. Patients with persistent incontinence were reevaluated with video urodynamic studies.

RESULTS

Mean interval since colpocystourethropexy was 6.9 years. Successful results (greater than 80% satisfaction and the use of 1 or no pad daily) were reported by 41 patients (69%), who were significantly younger at the time of surgery than those with unsatisfactory results. In the latter group significant urge incontinence was present in 61% before the repair and in 63% postoperatively, suggesting an additional nonanatomical cause, which was confirmed by postoperative video urodynamic studies.

CONCLUSIONS

When colpocystourethropexy was used for persistent urinary incontinence after previous surgical repair two-thirds of the patients had excellent long-term results. In patients with less satisfactory results a nonanatomical cause of urinary incontinence was a major factor.

Bladder acellular matrix graft: in vivo functional properties of the regenerated rat bladder

The purpose of this study was to determine whether the rat urinary bladder augmented by an acellular matrix graft can restore the bladder's low-pressure reservoir function and preserve normal micturition. After partial cystectomy (> 50%) and grafting with the bladder acellular matrix graft (BAMG), storage and voiding functions were monitored in 20 rats by means of a specially designed "micturition cage," leak-point cystography, and cystometry. After 4 months, sections (n = 6) were examined histologically to evaluate regeneration of bladder wall components within the BAMG. Bladder capacity and compliance increased progressively and were significantly higher in the grafted animals than in controls (partial cystectomy only), and volumes per void were significantly higher than in either control or normal animals. At 4 months, the regenerated urothelium, smooth muscle, blood vessels and nerves within the BAMG were qualitatively identical to normal bladder wall. Augmentation cystoplasty with the homologous BAMG leads to morphologic and functional rat bladder regeneration, thus enhancing low-pressure reservoir function and preserving normal micturition.

The impact of sacral root anatomy on selective electrical stimulation for bladder evacuation

Although different structures have been studied with electrostimulation to elicit bladder evacuation, only the sacral root remains feasible for clinical application at present. However, the resultant concomitant contractions of the bladder and sphincteric muscles have been the principal problem over the last few decades. Attempts to identify fibers within the sacral ventral root that innervate the detrusor predominantly have been made by microsurgery alone or in combination with advanced electrical blocking techniques. This article evaluates our past and present efforts to achieve voiding in light of the mixed nature of sacral root anatomy.

Composition and biomechanical properties of the bladder acellular matrix graft: comparative analysis in rat, pig and human

OBJECTIVE

To compare the composition and mechanical properties of the newly developed bladder acellular matrix graft (BAMG) with the normal urinary bladder in rat, pig and human.

MATERIALS AND METHODS

Rat, pig and human urinary bladders were harvested and divided into control and experimental groups. For the latter, BAMGs were prepared, and light and transmission electron microscopic studies performed. Strips from the normal bladders and the BAMGs (10 in each group) were tested under tension, and the ultimate tensile strength, maximum strain, and elastic modulus were determined from stress/strain curves.

RESULTS

Both types I and III collagen, as well as elastic fibres, were observed as major components of the matrix scaffold. There were more collagen type I fibres in the rat than in the pig and human BAMGs, whereas the pig, and particularly the human, both showed higher levels of type III collagen and elastic fibres. These different matrix scaffold patterns were confirmed by electron microscopy. Results from biomechanical testing showed no significant differences for strength, strain or elastic modulus between BAMG and control bladder strips, except in the rat where the maximum strain values were significantly lower.

CONCLUSION

There are variations in the acellular matrix structure with similar biomechanical properties between the BAMG and the normal urinary bladder in three different species. These results may underscore the potential of the BAMG. Furthermore, this in vitro model provides a suitable method to study the mechanical properties of the urinary bladder and may serve as a diagnostic tool for various investigations.

The latissimus dorsi bladder myoplasty to assist detrusor function

The objective of this study was to evaluate whether an innervated skeletal muscle might augment detrusor function. In four dogs we performed the latissimus dorsi myoplasty, a transfer of the latissimus muscle as an innervated free flap wrapped around the bladder. Stimulation of the latissimus dorsi free flap initially achieved an average bladder pressure of 45.8 +/- 8.41 cm H2O, sufficient for partial evacuation. After 4 months the muscle generated a maximal pressure of 82 cm H2O, resulting in an evacuation of 27.7%. For selected patients, the latissimus dorsi bladder myoplasty may provide an alternative to intermittent catheterization in the future.

In vitro functional properties of the rat bladder regenerated by the bladder acellular matrix graft

PURPOSE

To assess the response of rat urinary bladder regenerated by the homologous bladder acellular matrix graft (BAMG) to in vitro electrical and pharmacologic stimuli.

MATERIALS AND METHODS

In Sprague-Dawley rats, partial cystectomy (>50%) was performed, followed by BAMG augmentation cystoplasty. After 4 months, organ bath studies of tissue strips in 10 were used to compare the contractility of the BAMG regenerates and the corresponding host detrusor smooth muscle.

RESULTS

The BAMG regenerates exhibited contractile activity to electrical field stimulation and a qualitatively identical pattern of response to muscarinic, purinergic, alpha- and beta-adrenergic drug administration and nitric oxide. At 4 months after surgery, the maximum forces of contraction of the BAMG regenerates to carbachol stimulation amounted to close to 80% of the host bladder response. With electrical field stimulation, they equaled 44% and 62% of the host bladder response after 2.5 and 4 months, respectively. Histological and immunohistochemical studies confirmed the presence of receptors for neurotransmitters that these functional in vitro studies implied.

CONCLUSIONS

The present study provides further evidence that augmentation cystoplasty with the BAMG leads to functional regeneration of the rat bladder detrusor smooth muscle.

Bladder substitution: experimental data

Bladder enlargement or substitution using various segments of the gastrointestinal tract has been associated with significant metabolic and nutritional complications. Extensive research for other alternative materials, both synthetic and autologous, has revealed some difficulties including rejection, infection and stone formation. Most investigators believe that any material used for bladder augmentation must serve as a scaffold for the progressive ingrowth of all host bladder wall components, without infection or rejection. Recently, acellular matrix has been successfully utilized in experimental models for bladder substitution and appeared to satisfy many of these prerequisites.

Erectile response to transurethral alprostadil, prazosin and alprostadil-prazosin combinations

PURPOSE

Transurethral alprostadil has been shown to be efficacious in many men with erectile dysfunction. We compared transurethral alprostadil and prazosin alone, and in combination to treat this disorder.

MATERIALS AND METHODS

In this double-blind, placebo controlled study the erectile responses to transurethral alprostadil, prazosin and alprostadil-prazosin combinations were assessed in 234 men 26.8 to 81.5 years old with complete organic erectile dysfunction. Patients self-administered a random sequence of 7 doses in the clinic in 4 weeks. The erectile response was assessed using categorical and visual analog scales.

RESULTS

Full penile enlargement or rigidity was achieved by 165 of the 234 men (70.5%) after at least 1 active dose of medication. The most effective alprostadil dose (500 microg.) resulted in full penile enlargement or rigidity in 51.8% of administrations, whereas the most effective prazosin dose (2,000 microg.) and placebo resulted in a similar response in 12.7 and 2.7%, respectively (p <0.001). The 500/2,000 microg. alprostadil/prazosin combination, which resulted in full enlargement or rigidity in 58.9% of doses, was only slightly better than the most effective dose of alprostadil alone (500 microg.). However, combinations of 125/500 and 250/500 microg. alprostadil/prazosin were more effective (p <0.01) than 125 and 250 microg. alprostadil given alone, respectively. The most common side effect of therapy was penile pain, which rarely led to study discontinuation. Hypotension most commonly developed at the higher alprostadil-prazosin combination.

CONCLUSIONS

Transurethral alprostadil and alprostadil-prazosin combinations produced erections in men with complete organic erectile dysfunction. This combination therapy may be an option in patients who do not respond to transurethral alprostadil alone.

Functional rat bladder regeneration through xenotransplantation of the bladder acellular matrix graft

OBJECTIVE

To determine the decreased antigenicity of the bladder acellular matrix graft (BAMG) through xenotransplantation and to assess the in vivo and in vitro functional properties of the rat urinary bladder thus regenerated.

MATERIALS AND METHODS

After partial cystectomy (> 50%), BAMGs prepared from hamster, rabbit and dog urinary bladders were grafted to male and female Sprague-Dawley rats; 10 control rats underwent partial cystectomy only. Urinary storage and voiding function were monitored in 15 animals using a specially designed 'micturition cage' and cystometry. After 4 months, organ-bath studies and histological techniques were used to evaluate bladder regeneration in vitro in the grafted animals.

RESULTS

Clinically relevant antigenicity was not evident; no animal died from rejection and all bladder wall components regenerated in all BAMG xenografts. However, the degree and quality of regeneration varied. Muscularization, peak pressure, and bladder capacity were higher in the hamster BAMG-grafted animals, whereas in vitro contractility and compliance were best in the dog BAMG-regenerated bladders. All grafted bladders had significantly better capacity and compliance than the autoregenerated bladders after partial cystectomy alone.

CONCLUSIONS

The present in vivo and in vitro studies show that BAMG-augmentation cystoplasty can lead to morphological and functional regeneration of the rat bladder, preserving its low-pressure reservoir function. Because BAMG-regenerated bladders show functional innervation that is similar to normal bladders, they can work in coordination with the host bladder components, thus generating adequate intravesical pressure to produce sustained voiding. The decreased antigenicity makes heterologous BAMG transplants feasible without immunosuppression.

Free ureteral replacement in rats: regeneration of ureteral wall components in the acellular matrix graft

OBJECTIVES

To evaluate ureteral replacement by a free homologous graft of acellular matrix in a rat model.

METHODS

In 30 male Sprague-Dawley rats, a 0.3 to 0.8-cm midsegment of the left ureter was resected and replaced with an acellular matrix graft of equal length placed on a polyethylene stent. The animals were killed at varying intervals, and the grafted specimens were prepared for light and electron microscopy.

RESULTS

In all animals, the acellular matrix graft remained in its original position without evidence of incrustation or infection, and histologic examination showed complete epithelialization and progressive infiltration by vessels. At 10 weeks, smooth muscle fibers were observed; at 12 weeks, nerve fibers were first detected; at 4 months, smooth muscle cells had assumed regular configuration.

CONCLUSIONS

The ureteral acellular matrix graft appears to promote the regeneration of all ureteral wall components.

Continence mechanism of the isolated female urethra: an anatomical study of the intrapelvic somatic nerves

PURPOSE

A neuroanatomical study was initiated to gain better insight into the continence mechanism of the isolated urethra in women.

MATERIALS AND METHODS

We performed a detailed gross and histological neuroanatomical study to identify the intrapelvic somatic pathway from the sacral spinal cord to the female urethral sphincter. Gross anatomical dissection was performed in 5 formalin fixed female adult pelvises by tracing the autonomic nerves from the pelvic plexus and the spinal somatic nerves from S2-S4 to the urethral sphincter. Immunohistochemical staining of urethral step sections with a neuropeptide specific antibody was performed to demonstrate the course of the periurethral somatic nerves in relation to the vaginal wall.

RESULTS

Our study demonstrated an intrapelvic somatic pathway derived from the S2, S3 and S4 sacral roots, distinct from the peripheral pudendal nerve, supplying the levator ani and the urethra. The somatic nerves travel beneath the endopelvic fascia in close relation to the inferior vascular pedicle of the bladder and are susceptible to injury during radical pelvic surgery. Mixed autonomic fibers from the pelvic plexus travel along the course of the ureter and are also intimately associated with the vascular pedicle of the bladder. Immunohistochemical staining of urethral step sections demonstrated that the periurethral nerves travel in close relation to the lateral and anterior vaginal wall.

CONCLUSIONS

We believe that the identification of intrapelvic somatic pathways to the urethra provides a basis for developing surgical techniques to preserve urethral somatic innervation during radical pelvic surgery in women.

Neurostimulation for bladder evacuation: is sacral root stimulation a substitute for microstimulation?

OBJECTIVE

To determine by anatomical and functional studies whether stimulation of sacral rootlets might permit selective stimulation of autonomic fibres, thus avoiding the detrusor/sphincter dyssynergia characteristic of current techniques of neurostimulation for bladder evacuation.

MATERIALS AND METHODS

In 10 male mongrel dogs, the S2 root was isolated and its constituent rootlets followed from their origin in the spinal cord to the point of exit from the dura. The entire root and the individual rootlets were then stimulated, including intra- and extra-dural stimulation and at proximal, mid and distal levels.

RESULTS

Neuroanatomical and histological findings showed that rootlets of ventral S2 maintain their identity throughout their intradural course; some carry predominantly autonomic fibres, some predominantly somatic and some a mixture of the two.

CONCLUSION

It appears surgically feasible to identify, isolate and sever the predominantly somatic rootlets intradurally, sparing the predominantly autonomic rootlets for inclusion in extradural electrode placement around the entire sacral root, thus eliminating sphincteric interference with detrusor contraction for voiding at low pressure.

Reproduction of functional smooth muscle tissue and partial bladder replacement

OBJECTIVE

To find a means of bladder augmentation that would avoid the complications encountered with the use of bowel segments, using a newly developed acellular biomaterial, the bladder acellular matrix graft (BAMG), as a homologous graft.

MATERIALS AND METHODS

Thirty-four rats underwent a partial cystectomy (40-50%) and grafting with a BAMG of equal size. Eleven rats died within the first 72 h. probably from urinary leakage caused by obstruction of the bladder neck with stones or coagula; the surviving 23 were killed at varying intervals after cystectomy and examined.

RESULTS

After providing initial bladder enlargement, the graft was progressively infiltrated by the vessels and smooth muscle cells of the host: furthermore, the mucosal lining was complete within 10 days. After 4 weeks, all bladder wall components were evident histologically in the graft. The ingrowth was complete after 8 weeks, except for neural regeneration, which was only partial. At 12 weeks, the bladder wall muscle structure in the graft was so well developed that it was difficult to delineate the junction between host bladder and BAMG. Neural regeneration continued to improve. Normal bladder capacities were maintained throughout the study.

CONCLUSION

The BAMG appears to serve, without rejection, as a framework of collagen and elastin for the ingrowth of all bladder wall components. The reason for the better acceptance of the BAMG than of other bladder augmentation grafts requires further investigation.

Voiding dysfunction in human immunodeficiency virus infections

PURPOSE

We prospectively evaluated the current spectrum of urodynamic pathology in patients infected with human immunodeficiency virus (HIV) who presented with voiding dysfunction.

MATERIALS AND METHODS

We obtained a directed genitourinary and neurological history, and performed a physical examination and urodynamic testing in 18 patients. A 4-channel membrane urethral catheter was used to record intravesical and intraurethral pressures simultaneously.

RESULTS

Detrusor hyperreflexia was present in 28% of our patients and detrusor-sphincter dyssynergia in 28%. Detrusor areflexia, previously described as the most frequent abnormality, was uncommon in our series (6% of patients).

CONCLUSIONS

This changing proportion of urodynamic diagnoses may reflect a changing pattern of neurological manifestations of HIV infection due to more aggressive management. Urodynamic evaluation remains critical for precise diagnosis and treatment in patients with HIV who present with urinary symptoms.

Reinnervation of the rat bladder with a somatic nerve and a striated muscle flap

PURPOSE

Current techniques of ventral sacral root stimulation to regain voluntary motor control of the decentralized urinary bladder depend upon intact parasympathetic innervation of the detrusor. We investigated techniques that might allow restoration of motor control of the bladder after efferent parasympathetic impairment.

MATERIALS AND METHODS

In a chronic rat model, we evaluated whether motor control of a peripherally denervated bladder could be restored by transplantation of autologous excitable tissues and subsequent electrostimulation. Either a somatic nerve or a striated muscle flap was used as the transplant.

RESULTS

Four months after the initial surgery, electrostimulation of the somatic nerve implant provoked bladder contractions--a response that was blocked by atropine. Stimulation of the nerve innervating the striated muscle flap also provoked bladder contractions; these were not affected by atropine and were slightly reduced by hexamethonium.

CONCLUSION

Reinnervation of the bladder with somatic nerves or striated muscles is possible in principle. Future experiments will clarify the clinical significance of electrostimulation of such implants.

Intraoperative electrostimulation of the cavernous nerve: technique, results and limitations

PURPOSE

We studied the feasibility of inducing penile erection intraoperatively by stimulation of the cavernous nerves.

MATERIALS AND METHODS

In 16 men undergoing retropubic radical prostatectomy and 6 undergoing penile surgery for venous leakage electrostimulation was applied to both sides of the prostatic apex (prostatectomy group) or the hilum of the penis (venous surgery group).

RESULTS

Electrostimulation produced visible erection in 8 of the 16 prostatectomy patients and an increase in intracavernous pressure in 5 of the 6 venous surgery patients.

CONCLUSIONS

Electrostimulation of the cavernous nerves intraoperatively to produce penile erection is feasible. However, the technique must be further refined to be clinically useful, that is to localize the neurovascular bundle in men undergoing prostatectomy.

Sodium nitroprusside: physiologic effects as a nitric oxide donor in three species

Recent in vitro and in vivo studies have suggested that nitric oxide may be the neurotransmitter responsible for cavernous smooth muscle relaxation and penile erection. Sodium nitroprusside, after combining with different kinds of thiols in the cellular cytoplasm, can effect nitric oxide release. We undertook this study to determine the physiologic response to sodium nitroprusside injection when used to induce and maintain penile erection in three species. Sodium nitroprusside was injected in increasing concentrations into the cavernous tissue of rats, dogs and monkeys. Dosages injected were 10(-4) M, 10(-3) M and 10(-2) M in 10 rats; 10(-4) and 10(-3) M in five dogs and five monkeys. The volume of drug injected was 0.05 ml for the rats and 0.5 ml for dogs and monkeys. The results show a dose-dependent erectile response to sodium nitroprusside injection (mean intracavernous pressure increase of 102.4 cm H2O in dogs, and 98.4 cm H2O in monkeys after injection of 10(-3) M nitroprusside). However, only a slight increase in intracavernous pressure (mean increase 28.4 cm H2O after injection of 10(-2) M of sodium nitroprusside) was noted in rats. The drop in blood pressure was > 15 mmHg in dogs and monkeys, while in rats it varied according to the dose studied. Sodium nitroprusside induced excellent erections in dogs and monkeys with minimal alteration in blood pressure. However, administration in rats resulted in hypotension. Nitroprusside may not be an acceptable nitric oxide donor for the treatment of male erectile dysfunction.

The effect of intracavernous injection of potassium channel openers in monkeys and dogs

Cavernous smooth muscle relaxation is effected through a complex biochemical pathway; therefore, a defect in any step of this pathway may result in erectile dysfunction. Administration of pharmacologic agents which cause relaxation of the cavernous smooth muscle through a different mechanism may serve as an effective therapeutic alternative for impotent patients. To test this hypothesis two potassium channel openers, pinacidil and cromakalim, were used to initiate and maintain cavernous smooth muscle relaxation. The drugs were given as intracavernous injections in two animal models. In 10 dogs pinacidil and cromakalim produced full erection. With pinacidil (10(-2) M), the mean intracavernous pressure increased from a baseline pressure of 32.6 +/- 3.43 cm H2O to a peak intracavernous pressure of 131.8 +/- 12.01 cm H2O, and remained elevated for a period of 17.8 +/- 9.4 min. With cromakalim (10(-2) M) intracavernous pressure rose from a baseline pressure of 32 +/- 2.55 cm H2O to a peak intracavernous pressure of 140 +/- 3.39 cm H2O, for a period of 19.4 +/- 0.89 min. Additionally, in 5 primates injected with cromakalim (10(-2) M) intracavernous pressure rose from 24 +/- 3.81 to 131.2 +/- 7.56 cm H2O, for 27.0 +/- 4.79 min. It is concluded that both pinacidil and cromakalim can initiate and maintain erection in dogs and that cromakalim produces a similar erectile response in monkeys. Further study of the local and systemic effects of chronic injection is needed to determine whether this class of pharmacologic agents can provide therapy for impotent patients.

Response of guinea pig smooth and striated urethral sphincter to cromakalim, prazosin, nifedipine, nitroprusside, and electrical stimulation

Prazosin (an alpha-1-adrenergic blocker) and cromakalim (potassium channel opener), given alone, induced significant fatigue of the urethral sphincter at a concentration of 10(-4) M; both drugs combined achieved a significant sphincteric fatigue at a concentration of 10(-5) M each. To 10(-4) M hexamethonium (ganglionic smooth muscle blocker) and 10(-4) M decamethonium (nicotinic blocker of striated muscle) the striated urethral sphincter responded like striated muscle with no detectable function of its smooth muscle component. Therefore, the striated component seems to play a dominant role in sphincteric function. With calcium depletion or in the presence of a calcium channel blocker (10(-4) M nifedipine) the urethral sphincter showed a relative enhancement of response to electrical field stimulation when compared with smooth and skeletal muscle, whose responses were both significantly reduced. This phenomenon could not be explained with calcium-dependent, inhibitory, nitric oxide-releasing nerves, as the NO-synthase blocker N-nitro-L-arginine (10(-5) M to 5 x 10(-5) M) failed to induce the enhancement of sphincter contraction during electrostimulation found with calcium depletion. Still, NO-releasing nerves might play a role in sphincteric relaxation because sodium nitroprusside (10(-5) M) induced a significant relaxation of the urethral sphincter precontracted with 80 mM potassium. The potential to weaken sphincteric closure with drugs, exemplified by the results obtained in response to prazosin and cromakalim, would represent a therapeutic advance in the patient with neurogenic bladder dysfunction.

The detailed neuroanatomy of the human striated urethral sphincter

OBJECTIVE

To study the nerve supply of the striated urethral sphincter.

MATERIALS AND METHODS

The pelvis from six formalin-fixed male cadavers was dissected.

RESULTS

Cadaveric dissection revealed that both the intrinsic and extrinsic segments of the urethral rhabdosphincter receive their innervation from sacral roots S2-S4. The nerve fibres travel to their final destination via both the pudendal nerves and the nerve branches of the sacral roots. The terminal branches of the pudendal nerve enter the sphincteric area from the perineum. They separate shortly after they cross the ischial spine and run further ventromedially. Small branches approach the sphincter after their division from the dorsal nerve of the penis. The course of the pudendal nerve and its branching on the perineum are quite consistent. The pelvic branches travel inside the pelvis above the levator ani muscle. Among the cadavers the number of branches varied markedly, as did their site of termination (2.3 to 3.9 cm from the striated urethral sphincter). A substantial nerve approaching the sphincter from inside the pelvis was found. After it divided from the S2, S3 sacral roots it ran separately, initially just lateral to the fibres of the pelvic plexus and then on the dorsolateral surface of the rectum. In its terminal segment it dived into the levator ani muscle and terminated in the striated urethral sphincter.

CONCLUSIONS

We believe that the nerve supply to the striated urethral sphincter consists of branches from both the pudendal nerve and the 'extrapudendal' nerves that run above the levator ani muscle inside the pelvis. The variations in the course of the latter are remarkable.

Anatomy and strength of the tunica albuginea: its relevance to penile prosthesis extrusion

In 7 male cadavers the anatomical structure, thickness and tensile strength of the tunica albuginea of the penis, measured at specific locations, were determined. The tunica is composed of inner circular and outer longitudinal layers made up of collagen bundles. The outer layer appears to determine, to a large extent, the variation in thickness and strength of the tunica. The ventral groove (found between the 5 and 7 o'clock positions), which houses the corpus spongiosum, lacks outer bundles and appears vulnerable to perforation. The thickness of the tunica measured at the 7, 9 and 11 o'clock positions was 0.8 +/- 0.1 mm, 1.2 +/- 0.2 mm and 2.2 +/- 0.4 mm, respectively. Differences in the thickness of the tunica at specific locations were statistically significant (all p < or = 0.018). Symmetrical measurements were nearly identical in a mirror image arrangement (3, 5 and 1 at the 9, 7 and 11 o'clock positions, respectively). The stress on the tunica at penetration (breaking point pressure) measured at the 7, 9 and 11 o'clock positions was 1.6 +/- 0.2 x 10(7) N/m.2, 3.0 +/- 0.3 x 10(7) N/m2 and 4.5 +/- 0.5 x 10(7) N/m.2, respectively. The strength and thickness of the tunica correlated in a statistically significant manner with location (r = 0.911 and p = 0.0001). The most vulnerable area is on the ventral aspect (which lacks the longitudinally directed outer layer bundles), where most prostheses tend to extrude. This finding supports our belief that prosthesis extrusion often has an anatomical basis and is not merely a phenomenon caused by infection or compression.

The distribution of elastic fibrous elements within the human penis

OBJECTIVE

To determine the distribution of elastic fibres in the tunica albuginea and the erectile tissue of the penis.

MATERIALS AND METHODS

Samples of tunica albuginea or penile erectile tissue were taken from seven cadavers and five patients undergoing surgery. Light and electron microscopy were performed.

RESULTS

There were two anatomical regions in which elastic fibres were seen rarely: the proximal crus and the distal tunica. In the rest of the corpora cavernosa where the tunica was more compliant, the elastic fibres were in relative abundance. In the corpus spongiosum, abundant irregularly oriented elastic fibres were present; the densest elastic network was found in the glans penis and was composed of coarse elastic fibres. A perisinusoidal fibroelastic shell was seen in the glans, which was probably an extension of Buck's fascia. The elastic components within the sinusoids (cavernosal, spongiosal, and glanular) were similar but finer than the elastic lamellae in the penile arterial wall.

CONCLUSION

The elastic fibres were unevenly distributed, often forming an irregular network on which the collagen component rested. Elastic fibres were more abundant in the corpus spongiosum, around the blood vessels and surrounding the sinusoid of the corpus cavernosum.

The latissimus dorsi muscle for detrusor assistance: functional recovery after nerve division and repair

The treatment of choice for bladder atonia is clean intermittent catheterization. To eliminate the catheter-related morbidity and increase the quality of life for patients with an atonic bladder, the restoration of bladder contractility would be desirable. Based on our hypothesis that skeletal muscle might augment bladder contractility, we designed the present study to examine the ability of the latissimus dorsi muscle in situ to empty a bladder-like reservoir and to regenerate after division and repair of the supplying motor nerve. In 4 dogs, the left latissimus dorsi muscle was dissected, mobilized and wrapped around a bladder substitute (100-ml. silicone reservoir). Stimulation of the thoracodorsal nerve resulted in the evacuation of 63.8 +/- 6.2% of the reservoir's volume and a maximum pressure of 109.5 +/- 18.6 cm. H2O. Four months later, the thoracodorsal nerve supplying motor control to the muscle was transected and microsurgically reanastomosed. Using transcutaneous stimulation, we recorded the pressure generation and resulting evacuation at regular intervals for 8 months (that is, 12 months after the initial surgery). At the end of this period, the pressure was 79.3 +/- 12.1 cm. H2O (72.4% of the initial value), expelling 48.3 +/- 6.7% of total volume. This long-term study demonstrates: (1) the ability of the transposed latissimus dorsi muscle to evacuate a bladder-like reservoir; and (2) the regenerative potential of muscle and nerve after nerve transsection and repair. Use of skeletal muscle, which can be readily stimulated, may serve to facilitate bladder emptying and provide a treatment alternative to intermittent catheterization in the future.

Intracellular mechanism of penile erection in monkeys

To elucidate the sequence of events between the release of neurotransmitters and cavernous smooth muscle relaxation in erection, we studied the role of the cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) systems. In a well-established simian model, the effects of specific agonists and antagonists of the intracellular sequence for smooth muscle relaxation and potassium channel openers on the intracavernous pressure were examined. Sodium nitroprusside (10(-3) M), a nitric oxide releaser and thus a stimulant of the cGMP system, caused an increase in the intracavernous pressure from 82 to 115 cm H2O for 7 to 19 min and penile diameter from 24.8 +/- 2.28 to 43 +/- 4.87 mm. When nitroprusside was injected after methylene blue (10(-3) M), a specific antagonist of the enzyme guanylate cyclase, intracavernous pressure rise decreased significantly, but cromakalin, a potassium channel opener, provoked excellent increases after the block. A smaller dose of sodium nitroprusside (10(-4) M) caused an increase in intracavernous pressure from 35 to 85 cm H2O for 7 to 11.5 min. When nitroprusside was injected after zaprinast, a phosphodiesterase inhibitor, the increase in pressure ranged from 80 to 116 cm H2O for 15 to 30 min. Prostaglandin E1, an activator of the cAMP system, caused an increase in the intracavernous pressure of 20-80 cm H2O for 5 to 10 min, and an increase in penile diameter from 25 +/- 2.22 to 35 +/- 3.48 mm. The erectile response to PGE1, but not to cromakalin, was nearly abolished by ethylmaleimide, an adenylate cyclase blocker. The response to nitroprusside was significantly greater (P < 0.05) than to PGE1. Both systems, cAMP and cGMP, may be involved in cavernous smooth muscle relaxation, and cGMP is probably the predominant intracellular second messenger in penile erection in monkeys. Stimulants of the cGMP system, such as nitric oxide releasers, could represent a more physiological and effective approach in the treatment of erectile dysfunction.

Preoperative urodynamic evaluation: does it predict the degree of urinary continence after radical retropubic prostatectomy?

Preoperative evaluation of voiding patterns and detailed urodynamic evaluation before radical retropubic prostatectomy was carried out in an attempt to identify patients at higher risk of developing urinary incontinence postoperatively. Ninety-two men, mean age 64 years (range 54-72), who completed 1 year of follow-up after radical retropubic prostatectomy for clinically localized adenocarcinoma of the prostate were included in the study. According to the preoperative urodynamic findings, patients were divided into two main groups: group 1 (n = 64) patients with normal urodynamic findings, and group 2 (n = 28) patients with abnormal urodynamic findings. The latter group was further subdivided according to the abnormality: detrusor instability (n = 12), weak sphincter mechanism (n = 9), and detrusor and sphincter instability (n = 7). The degree and incidence of urinary incontinence were evaluated in both groups at the 1-year follow-up visit. There was a substantial difference in the incidence of urinary incontinence between the two main groups with only 2 patients with incontinence in group 1 (3%) versus 11 patients in group 2 (39%). In addition, the incidence of incontinence in group 2 differed depending on the type of abnormality: the lower incidence occurred in patients with detrusor instability (17%) and the higher incidence in patients with both detrusor and sphincter instability (71%). Identification of sphincteric and bladder dysfunction preoperatively may indicate a high risk of urinary incontinence after radical prostatectomy.

Rat model for the study of penile erection: pharmacologic and electrical-stimulation parameters

We report the use of a modified rat model for the study of the mechanisms of penile erection. In 92 Sprague-Dawley rats, the cavernous nerve was stimulated with different pulse intensities and frequencies, and the intracavernous pressure, time to maximal pressure and total duration of tumescence were measured. A maximal response was elicited at 20 pulses per second (pps) and 1.5 mA. Using this as 100%, we determined the relative pressure responses obtained with other frequencies: 5 pps, 57.3% (p = 0.007), 10 pps, 84.9% (p = 0.043); 30 pps, 99.5% (p = 0.832); 40 pps, 97.8% (p = 0.168); 50 pps, 90.9% (p = 0.021); 100 pps, 76.1% (p < 0.001). The time to maximal pressure varied with different frequencies, but was in all cases significantly different from the 20-pps response. Erection time during continuous cavernous nerve stimulation was significantly longer with frequencies below 20 pps (10 and 5 pps). In 30 rats, the physiologic response to intracavernous injection (0.03 ml) of acetylcholine, atropine, guanethidine, norepinephrine, phenylephrine, papaverine, terbutaline (intravenous also) and phentolamine was measured. Papaverine caused a dose-dependent rise in pressure; acetylcholine, atropine (a parasympathetic blocking agent) and guanethidine all had minimal effects. Phentolamine and norepinephrine increased systemic blood pressure, whereas phenylephrine decreased the intracavernous pressure in response to electrostimulation significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of nerve stimulation on blood flow in the urinary bladder, urethra and pelvic floor in the dog

Pelvic organs have triple innervation from the pelvic, sympathetic and pudendal nerves. Peripheral effects can be studied by neurostimulation of the nerves, whereas the topography of the spinal cord neurons can be determined by horseradish peroxidase tracing. We have evaluated the neurophysiologic effects of the nerves at their target organs by intraoperative electric stimulation and compared the effects to the anatomical innervation areas. These zonal areas were determined by blood flow alterations, measured with nine different microspheres. Pelvic nerve stimulation showed bladder contraction with no significant blood flow changes during stimulation. Sympathetic nerve stimulation caused moderate detrusor contraction and pressure increase in the bladder neck and intraprostatic area. Regional blood flow showed a four-fold increase in the bladder neck area during neurostimulation. Pudendal nerve stimulation revealed an intraurethral pressure increase with a 3.5-fold increase of blood flow in the sphincteric area and in the pelvic floor musculature.

Drainage and reflux characteristics of antireflux ureteral double-J stents

We tested three antireflux double-J stents and compared them with common double-J stents in ex vivo canine urinary systems. At a physiologic flow rate, the drainage function of the antireflux stents proved to be sufficient; however, at a supraphysiological flow rate, drainage was inferior to that of the common double-J stent. Our reflux study demonstrated high-grade reflux with the common double-J stent, which transmitted more than 90% of the bladder pressure to the renal pelvis. The antireflux stents prevented this to a certain degree by both a reduction in and a delay of pressure transmission to the renal pelvis. In preliminary clinical trials, vesicorenal reflux was not detectable radiologically with the antireflux stents.

Diagnosis of urethral diverticula in women: value of MR imaging

OBJECTIVE

The purpose of this study was to determine the role of MR imaging in the diagnosis of urethral diverticula in women.

SUBJECTS AND METHODS

In 20 patients (mean age, 47 years), MR imaging was performed (1.5-T); unenhanced T1-weighted and T2-weighted images and contrast-enhanced T1-weighted images were obtained. MR imaging findings were compared with findings on urethrograms (including voiding cystourethrograms or double balloon catheter studies) in 16 patients, urethroscopic findings in 18, and surgical findings in 13. MR images were assessed for the presence, size, number, and location (anterior or posterior to the urethral lumen and relationship to the neck of the bladder) of diverticula, visualization of ostia, and presence of any concomitant complications. Sixteen of 20 patients had urethral diverticula: uncomplicated (simple) urethral diverticula in 13 patients; a diverticulum with a stone in one; a diverticulum with chronic granulation in one; and a diverticulum with adenocarcinoma in one. In the remaining four patients, the diagnoses included Gartner's duct cyst (one) and paraurethral cyst (one); urethras were deemed to be normal in two.

RESULTS

In 13 patients who had surgery, MR images correctly showed the presence or absence of diverticula, whereas urethrography was correct in nine (69%) and urethroscopy in 10 (77%). Compared with surgical findings (20 diverticula in 12 patients), MR images depicted 14 (70%) of 20 diverticula and urethrography and urethroscopy each depicted 11 (55%) of 20. The ostium of the diverticulum could not be identified on MR images. The use of MR contrast material did not contribute to lesion detection, but the enhanced images were superior to unenhanced images in showing granulation tissue and carcinoma, although they did not help in their differentiation.

CONCLUSION

MR imaging is accurate for showing urethral diverticula, but owing to its high cost, it should be considered only when urethroscopic or urethrographic findings are equivocal or when patients are unable to undergo these procedures and clinical findings strongly suggest a urethral diverticulum.

High flow priapism: a spectrum of disease

We describe 4 cases of high flow arterial priapism, ranging from 1 week to 3 years in duration. The mode of presentation, evaluation using a duplex scanner, treatment and ultimate resolution are discussed. In 1 patient treated with ice compression the erection subsided spontaneously. One patient underwent percutaneous embolization and achieved detumescence. In 2 men a vascular pseudocapsule formed around the site of the ruptured cavernous artery that provided an important anatomical landmark for intraoperative localization. The ruptured branch of the cavernous artery was ligated in an open procedure. Based on these cases and a review of the literature, we outline a modified diagnostic and therapeutic approach for patients with high flow arterial priapism.

Stimulated pressure response of the ileocolonic junctional zone and its use as a continence mechanism in a canine model

Mechanisms for maintaining passive continence in the efferent limb of urinary diversions include compression of tissue, peristalsis, equilibration of pressure and use of valves. Motor activity and pressure in the ileum, ileocecal valve (ICV) and the colon were evaluated in dogs. Spontaneous activity and pressure were compared with stimulated pressure response and activity. Stimulation was performed at the pelvic nerve and the small nerves in the mesenterium, as well as direct neurostimulation of the bowel. Resting pressure at the ICV was 12.7 +/- 0.4 cmH2O rising to 26.4 +/- 2.2 cmH2O during spontaneous depolarization. Stimulation of the pelvic nerve resulted in increased colonic motor activity with unchanged pressure. Electric stimulation of small mesenterical nerves to the ICV increased pressure in the ICV to 35.0 +/- 4.1 cmH2O, while direct myoelectric stimulation of the ICV zone increased the intraluminal pressure to 75.0 +/- 3.2 cmH2O. Termination of the electric stimulation was followed by a slow decrease of pressure to the resting level over a period of 30-45 s. Maintaining continence at the ICV with long-term constant or intermittent stimulation seems feasible.

Motility and intraluminal pressure of the ileocolonic junctional zone and adjacent bowel in a canine model

The exact role of the ileocecal valve (ICV) at the junction of small and large bowel is not well understood. Bowel segments used for the construction of urinary reservoirs incorporate the ICV. In the Indiana pouch its natural continence is used as one principle for achieving continence of the efferent limb. Motor activity and pressure in the ICV, the ileum and colon were registered in eight dogs. Myogenic activity of the bowel consisted of slow waves, irregular spontaneous contractions and superimposed spikes. Pressures of 7.2 +/- 0.3 cmH2O were recorded in the ileum and of 5.6 +/- 0.4 cmH2O in the colon. The pressure in the ICV was 12.7 +/- 0.4 cmH2O rising to 26.4 +/- 2.2 cmH2O during spontaneous depolarization. Balloon dilatation of the ileum resulted in relaxation of the ICV in 76% of experiments, whereas colonic distension was followed by a pressure increase in the ICV region in 80% of experiments. In 16% of cases a relaxation of the ICV area and a weaker response after repeated dilatation was noted. These findings make the ICV an unreliable continence mechanism as its long-term continence can not be predicted despite intraoperative evaluation. Additional measures to ensure consistent continence at the ICV (e.g. electric stimulation) need to be studied.

Pelvic plexus denervation in rats causes morphologic and functional changes of the prostate

The effect of pelvic plexus denervation on biochemical, morphologic and functional characteristics of the rat prostate was assessed in 11 adult Sprague-Dawley rats. Unilateral denervation was performed by removing the right pelvic ganglion from the surface of the prostate; the contralateral lobe was similarly dissected, but not denervated, to serve as a control. After 15 to 18 days, the prostate was excised and specimens from both sides were used for morphologic (light and electron microscopy) and biochemical studies (sodium-dodecylsulfate-polyacrylamide gel electrophoresis). With light microscopy, histologic features of the denervated prostate showed an overall decrease in cell height and a reduction of the clear apical area of the supranuclear region. At an ultrastructural level, denervated prostatic epithelial cells showed a slight, but significant, reduction in the number of secretory granules, a decrease in the height of the supranuclear region, and fewer and less abundantly dilated apical cisternae of endoplasmic reticulum. These changes indicate a modification of the secretory activity and reflect a change in epithelial metabolism, which was further supported by the results of SDS gel electrophoresis: the denervated prostate tissue showed an increase in the expression of 108 kDa and 80 kDa protein bands and a decrease in the expression of the 45 kDa protein band. This modification in the protein content is probably temporal and would undergo further evolution with time. The finding that denervation of the prostate causes significant morphologic and functional changes of the glandular epithelium strongly suggests that prostate function is not subject solely to the regulatory influence of the hormonal milieu. It is also dependent on the anatomical and, quite possibly functional, integrity of the nervous system.

Phenotypic and cytogenetic characterization of a human corpus cavernosum cell line (DS-1)

We report here the establishment and characterization of a corpus cavernosum cell line (DS-1) from human penile tissue. This is the first cell line of its type derived from cavernosum tissue. DS-1 cells have become immortalized in culture, and show growth in monolayers. These cells have a doubling time of about 45 h in in vitro culture. Cytogenetic analysis by G-banding demonstrated a diploid karyotype with a model chromosome number of 46. The chromosome constitution of DS-1 cells was found to be male (XY), in 28/30 cells scored. Two of the 30 cells showed an extra structurally rearranged "marker" chromosome, that appeared to be a derivative of chromosome 18 with excessive chromosome on the short arm. Ploidy analysis revealed that the majority of DS-1 cells had a DNA index of one. About 35% cells were found to be in G-1 phase and 52% cells in S phase. Light and electron microscopy of DS-1 cells and original penile tissue showed typical characteristics of this tissue. Immunocytochemistry studies using antibodies to smooth muscle actin, desmin, vimentin and cytokeratin (LP34, CAM5.2) showed that the DS-1 cell line had predominantly smooth muscle cells, as these cells were positive for smooth muscle actin, desmin and vimentin.

Peyronie's plaque: surgical treatment with the carbon dioxide laser and a deep dorsal vein patch graft

We describe a procedure for ablation of Peyronie's plaque using the carbon dioxide laser, which allows one to remove all palpable evidence of plaque while at the same time avoiding the creation of a large defect in the tunica albuginea requiring coverage with a large graft. The plaque is removed by making either a longitudinal or transverse incision in the plaque with a focused carbon dioxide laser beam from a hand held probe, and evaporating the plaque substance from the undersurface by tangentially directing the laser beam. It is possible to remove large dystrophic calcifications from within the plaque and to augment the repair in the area of greatest curvature using the deep dorsal vein as a patch graft. In cases of narrow plaques relaxation incisions and venous patch grafting alone are usually sufficient to correct the deformity. Our experience with 12 patients is summarized and 2 cases are reported in detail to illustrate the versatility of the procedure.

Implantable penile venous compression device: initial experience in the chronic canine model

A prosthetic penile venous compression device was surgically placed in 14 dogs to assess the effects of chronic device implantation and repeated device cycling on cavernous tissue. Duration of device implantation ranged from 37 to 224 days; total number of device cycles ranged from 8 to 59. At recovery, erection was induced by electrostimulation of the pelvic nerve. The device successfully prolonged intracavernous elevation for as much as 30 minutes after inflation. Histologic examination of representative tissue sections through the corpora revealed no evidence of neural injury, vascular compromise, or tissue atrophy. The implantable venous compression device may offer an improved method of treatment of venogenic impotence.