Gene transfer with a vector expressing Maxi-K from a smooth muscle-specific promoter restores erectile function in the aging rat.

Previous reports have demonstrated that gene transfer with the alpha, or pore-forming, subunit of the human Maxi-K channel (hSlo) restores the decline in erectile capacity observed in established rat models of diabetes and aging. Preliminary data from a human clinical trial also showed safety and potential efficacy in 11 men treated with the same plasmid construct expressing the Maxi-K channel. In all instances, the original plasmid was driven by the heterologous cytomegalovirus promoter which is broadly active in a wide variety of cell and tissue types. To more precisely determine the contribution of the corporal myocyte to the observed physiological effects in vivo, we report here our initial work using a distinct vector (pSMAA-hSlo) in which hSlo gene expression was driven off the mouse smooth muscle alpha-actin (SMAA) promoter. Specifically, older rats, with diminished erectile capacity, were given a single intracorporal injection with either 100 mug pVAX-hSlo or 10, 100 or 1000 mug pSMAA-hSlo, or vector or vehicle alone. Significantly increased intracavernous pressure (ICP) responses to cavernous nerve stimulation were observed for all doses of both plasmids encoding hSlo, relative to control injections. These data confirm and extend previous observations to document that smooth muscle cell-specific expression of hSlo in corporal tissue is both necessary and sufficient to restore erectile function in aging rats.

Expression of myosin isoforms in the smooth muscle of human corpus cavernosum.

The molecular interaction between smooth muscle (SM) myosin and actin in the corpus cavernosum (CC) determines the erectile state of the penis. A key mechanism regulating this interaction and subsequent development and maintenance of force is alternative splicing of SM myosin heavy chain (MHC) and 17 kDa essential SM myosin light chain (MLC) pre-mRNAs. Our aim was to examine the relative SM myosin isoform composition in human CC. Tissue samples were obtained from 18 patients with erectile dysfunction (ED), Peyronie's disease, or both. One specimen was obtained during a transgender operation. Patients then were stratified according to presence of diabetes mellitus, hypertension, ED, or Peyronie's disease, as well as failure of phosphodiesterase-5 (PDE5) inhibitors and history of previous pelvic or penile surgeries, radiation, or both. Our results revealed that all human CC samples expressed only the SM-A isoform. There was a predominance of SM2 isoform mRNA relative to SM1 across all samples, with a mean of 63.8%, which correlated with protein analysis by gel electrophoresis. A statistically significant difference was found between patients who had undergone previous pelvic surgery, radiation, or both and those who did not. The ratio of LC(17b) to LC(17a) was approximately 1:1 for all patients, with a mean of 48.9% LC(17b). Statistical difference was seen in the relative ratio of LC(17b) to LC(17a) among the group who failed conservative therapy with PDE5 inhibitors compared with all others. In conclusion, we determined the SM myosin isoform composition of human CC and present for the first time differences in relative myosin isoform expression among patients with several risk factors contributing to their cause of ED. Our data reflect the fact that alternative splicing events in the MHC and 17 kDa MLC pre-mRNA may be a possible molecular mechanism involved in the altered contractility of the CCSM in patients with ED.

Ageing causes cytoplasmic retention of MaxiK channels in rat corporal smooth muscle cells.

The MaxiK channel plays a critical role in the regulation of corporal smooth muscle tone and thereby erectile function. Given that ageing results in a decline in erectile function, we determined changes in the expression of MaxiK, which might impact erectile function. Quantitative-polymerase chain reaction demonstrated that although there is no significant change in transcription of the alpha- and beta-subunits that comprise the MaxiK channel, there are significant changes in the expression of transcripts encoding different splice variants. One transcript, SV1, is 13-fold increased in expression in the ageing rat corpora. SV1 has previously been reported to trap other isoforms of the MaxiK channel in the cytoplasm. Correlating with increased expression of SV1, we observed in older rats there is approximately a 13-fold decrease in MaxiK protein in the corpora cell membrane and a greater proportion is retained in the cytoplasm (approximately threefold). These experiments demonstrate that ageing of the corpora is accompanied by changes in alternative splicing and cellular localization of the MaxiK channel.

Gene transfer for the therapy of erectile dysfunction: progress in the 21st century.

Gene transfer represents the next potential era of advancement in medicine for the prevention of the effects of aging or for treatment of genetic or acquired disease. For gene transfer to be a practical successor to today's oral and minimally invasive therapies, the product must have a high safety profile and a long duration of effectiveness to correct the need for on-demand administration. Several types of vectors have been used in preclinicals studies, but because of widely publicized adverse events, progress using viral vectors in humans has been limited. There is a current phase I human trial using naked DNA as the vector with the maxi-K gene to modify cellular contractility. Preliminary results in the safety trial thus far have shown no treatment-related adverse events, no transfer to the semen, and the possibility of efficacy in one participant.

Can self-administered questionnaires supplant objective testing of erectile function? A comparison between the International Index Of Erectile Function and objective studies.

To determine whether the results of the self-reported International Index of Erectile Function (IIEF) to assess erectile function can overestimate the degree of erectile impairment. A total of 32 consecutive patients seeking treatment for erectile dysfunction (ED) at a urologist's office were evaluated by completion of the erectile function domain of the IIEF. Nocturnal penile tumescence testing using the Rigiscan (Timm Medical Technologies Inc., USA) was performed in these patients after completion of the IIEF. The median IIEF-6 score was 9 of 30 (range, 1-25; mean, 11/30). Rigiscan results were abnormal in six patients (19%), normal in 25 patients (78%), and unable to interpret in one patient (3%). IIEF-6 scores were subdivided by severity along with Rigiscan results. There was no correlation between age, IIEF score, or Rigiscan results. In conclusion, the IIEF is a useful tool and is helpful for follow-up of a patient to evaluate efficacy of treatments for ED, but should not replace objective testing to diagnose the quality of ED.

Cutaneous temperature measurements in men with penile prostheses: a comparison study.

To evaluate and compare the cutaneous temperature of the penis in normal men, those with erectile dysfunction (ED), those with semirigid penile prostheses (SRPPs), and those with inflatable penile prostheses (IPPs), and those before and after trimix injection to create a penile erection. A total of 68 patients were evaluated. Five patient groups were identified, including men with normal erectile function, with ED, with SRPPs, with IPPs, and following intracavernosal injection of trimix solution. Cutaneous glans temperature increased significantly by more than 2.2 degrees C in the trimix-injected group compared with all other groups (P<0.001). Using cutaneous temperature measurements of the penis, patients with SRPPs had significantly lower cutaneous glans temperatures than normals (P<0.02), those in the ED group (P<0.04), and those in the IPP-deflated group (P<0.01). The mean temperature difference was 1.44+/-0.40 degrees C. Using cutaneous temperature measurements of the penis, men with SRPPs have a colder glans as compared with men with normal erectile function, ED, IPPs, and those who have received an injection of trimix. Men with normal erectile function, ED, and IPPs did not have significant cutaneous temperature differences.

Effects of age, menopause, and comorbidities on neurological function of the female genitalia.

The aim of this study was to investigate the effects of age, menopause, and comorbidities on neurological function of the female genitalia using a noninvasive, validated technique. In all, 58 consecutive women were enrolled in the study. Biothesiometry was performed at five genital sites and one peripheral site with S2 dermatome distribution. Kruskal-Wallis one-way ANOVA on ranks was used to evaluate the relationship between age and vibratory sensation. Bivariate and regressional analyses were performed to evaluate the effects of age, menopause and comorbidities on genital sensation. The mean age was 44.6+14.8 y (range 20-78 y). Vibration thresholds increased with advancing age at all six sites. Multilinear regression analysis indicated that menopause and increasing age negatively affect sensation. History of herniated lumbar disc, vaginal delivery, and diabetes variably affected genital sensation. There is a significant increase in vibration thresholds (indicating worsening neurological function) in women as they age and undergo menopause. Biothesiometry is a technique for evaluating genital neurological function in women with coexisting morbidities.

A nonimaging scintillation probe to measure penile hemodynamics.

UNLABELLED: We have developed a penile nonimaging scintillation (PNIS) probe consisting of a plastic well-type scintillation crystal interfaced to a portable computer and acquisition board. This report describes the design of the PNIS probe, performance characteristics, mode of usage and illustrative results which demonstrate its capabilities. METHODS: With the PNIS probe, penile blood-pool studies were performed in nine patients utilizing 3.7 MBq (100 microCi) autologous 99mTc-labeled red blood cells (RBCs). Venous blood standards were assayed to enable conversion of the count rate to volummetric measurements. Washin of peripherally administered 99mTc-RBCs was mathematically analyzed to estimate penile blood volume and cavernosal flow rate in the flaccid state. The rate of change of penile blood volume after intracavernosal vasodilators was used to generate measures of stimulated flow. RESULTS: A major advantage of this device over the gamma-camera is a 3300-fold increase in count rate sensitivity, which allows for markedly improved temporal resolution while significantly reducing the radiopharmaceutical dosage. Additionally, the PNIS probe is portable, economical and is not dependent on operator-defined regions of interest. Count rate sensitivity is relatively constant within the bore, with the exception of the proximal region adjacent to the opening, where geometric efficiency is reduced. CONCLUSION: The PNIS probe is an effective device for measuring penile activity in radionuclide studies, allowing for acquisition of time-activity curves of the penis during flaccid washin of peripherally labeled red blood cells and after pharmacologic stimulation to induce erection.

Pharmacological studies of human erectile tissue: characteristics of spontaneous contractions and alterations in alpha-adrenoceptor responsiveness with age and disease in isolated tissues.

1. The pathophysiology of impotence related to vascular smooth muscle dysfunction in the male corpus cavernosum was studied on human isolated erectile tissue (HET). Studies were conducted on 140 sections of HET obtained from 38 male patients undergoing surgery for implantation of penile prostheses to correct underlying erectile dysfunction. 2. Spontaneous myotonic oscillations were characteristic of greater than 90% of all HET preparations at 37 degrees C. These spontaneous oscillations were markedly attenuated by indomethacin, BW755C, nifedipine, removal of extracellular Ca2+, or lower temperatures (less than or equal to 32 degrees C), but were not sensitive to inhibition by atropine, phentolamine or tetrodotoxin. Our data suggest that the oscillations may, at least in part, result from the generation and/or release of a stable cyclo-oxygenase product and a consequent increase in transmembrane Ca2+ influx. 3. The phenylephrine-induced contractions in HET may be reliably assayed up to 24 h after surgical removal, without significant alterations in the EC50, maximum response (Emax) or slope index of the steady-state concentration-response curve to phenylephrine. 4. The competitive and surmountable nature of the antagonism of phenylephrine-induced contractions by prazosin and yohimbine allowed calculation of antagonist dissociation constants. The calculated pKb values for prazosin and yohimbine, respectively, were 9.47 +/- 0.49 and 5.54 +/- 0.22. The rank order of agonist potency in HET was: noradrenaline = phenylephrine much greater than clonidine. These data indicate the presence of a population of membrane receptors that are predominantly of the alpha 1-adrenoceptor subtype. 5. The entire patient population was stratified on a decennial basis into five age groups, and each age group was subsequently subdivided into diabetic and nondiabetic diagnostic categories. With respect to the steady-state phenylephrine concentration-response curves, a Winer two-factor analysis of variance revealed a significant effect of age on the calculated pEC50 value, as well as a significant age-diagnosis interaction. A post hoc statistical analysis for unpaired samples yielded significant differences between pEC50 values for diabetic and nondiabetic patients in age groups 41-50 and 61-70 years. In addition, a Winer two-factor analysis of variance also detected a significant effect of age on the calculated E.., value. 6. In conclusion, our studies demonstrate that spontaneous contractions in HET are likely to be mediated by the generation and release of a stable cyclo-oxygenase product. Furthermore, the results of both agonist and antagonist studies are consistent with the presence of a homogeneous alpha x-adrenoceptor population. Lastly, the responsiveness of isolated HET to phenylephrine was shown to be altered by both age and disease.

Facile acylation of sterically hindered alcohols through ketene intermediates.

[reaction--see text] Carboxylic acids possessing strongly electron withdrawing substituents in the alpha-position in the presence of DCC acylate sterically hindered and chemically sensitive alcohols. The pattern of reactivity, the deuteration experiments, and the formation of a product derived from a [4 + 2] cycloaddition reaction corroborate the existence of ketene intermediates in the reaction.

Use of intralesional verapamil to dissolve Peyronie's disease plaque: a long-term single-blind study.

OBJECTIVES: Multiple conservative therapies for the treatment of Peyronie's disease have been offered with variable and poor response rates. Calcium channel blockers have been shown in vitro and in vivo to inhibit secretion and synthesis of extracellular matrix, including collagen, glycosaminoglycans, and fibronectin, as well as causing increased collagenase and anti transforming growth factor-beta activity. Calcium antagonists, including verapamil, are effective in stimulating the remodeling and degradation of extracellular matrix in tissue by altering the metabolic pathways of fibroblasts. Recently, a pilot study (1994) showed preliminary promising results in treating plaque caused by Peyronie's disease. This randomized single-blind placebo-based study (1994 to 1996) was undertaken to confirm the hypothesis. METHODS: In this randomized single-blind study, 14 patients completed the study and were divided into two groups: the verapamil treatment group (n = 7) or the control saline group (n = 7). Verapamil or saline was injected directly into the Peyronie's plaque once a week for 6 months. Patients were evaluated before and after treatment with duplex ultrasound to confirm the extent of the lesion and to measure volume of the plaque, and by interview and mailed questionnaire 3 months after treatment. Patients being treated with oral calcium antagonists were excluded from the study. RESULTS: A decreased plaque volume was measured in 57% of the verapamil-treated men versus 28% in the control group (P <0.04). Penile curvature demonstrated an improvement trend of 37.71 +/- 9.3 degrees to 29.57 +/- 7.3 degrees in the verapamil-treated patients, but the difference was not significant (P <0.07). Plaque softening was noted in all patients treated with verapamil. There was significant objective improvement in plaque-associated penile narrowing in all patients in the verapamil group. Subjective plaque-associated erectile dysfunction (quality of erection) showed improvement in 42.87% of the verapamil group versus none in the control group (P <0.02). There was no local or systemic toxicity except for an occasional ecchymosis/bruise at the injection site. After a positive clinical response, plaque size, penile angulation, and symptoms continued to improve. Decrease in plaque size was noted in each of the responders in the first 3 months. CONCLUSIONS: This randomized single-blind study suggests that intralesional injection of calcium channel blocker may be a reasonable approach in some selected patients for the treatment of Peyronie's disease with noncalcified plaque and penile angulation of less than 30 degrees. Patients whose plaque failed to respond to intralesional verapamil therapy within 3 months or whose angulation was greater than 30 degrees at presentation were more likely to benefit from surgery.

Nonassociation of hyperamylasemia and prostatic disease.

The possible correlation of hyperamylasemia and prostatic disease was investigated in patients with benign prostatic hyperplasia, adenocarcinoma of the prostate, and in patients without clinical evidence of prostatic lesion. Our results indicate that prostatic lesions whether benign or malignant are not associated with either elevation of serum amylase or abnormal isozyme zymograms.

Evaluation of first 406 patients in urology department based Center for Male Sexual Dysfunction.

Four hundred six patients with a complaint of erectile dysfunction were evaluated in a urology department based Male Sexual Dysfunction Center. Results of physical examination, medical and psychosexual history, nocturnal penile tumescence (NPT), penile blood pressure, visual sexual stimulation, hormonal screen, and partner interview were used in establishing the final diagnosis. A summary of the final diagnoses is as follows: organic impotence 117 (28.8%), psychogenic impotence 161 (39.7%), combined factors 102 (25.1%), and dysfunction of unknown origin 26 (6.4%). Data analysis confirms that to establish a diagnosis of organic erectile failure multiple objective measurements in combination with patient and partner history are necessary.

Instability and rotation of silver silicone penile prosthesis.

Four cases of a similar complication in patients who have had the Jonas silver silicone prosthesis implanted are reported. The patients complain of instability and rotation of the prosthesis to a position that stands out from the body, no matter what the initial position of the prosthesis. The rotation causes difficulty with coitus. The explanation is one of a manufacturing and not a surgical defect.

Accuracy of the initial history and physical examination to establish the etiology of erectile dysfunction.

OBJECTIVES: Because of its implications for possible therapy, the ability to establish a diagnosis of erectile dysfunction (ED) solely on the basis of history and physical examination has been a matter of controversy. The determination of the etiology of ED based on history and physical examination is evaluated in this present study. METHODS: Consecutive patients presenting for evaluation of ED were evaluated by careful history, physical examination, psychologic evaluation, and RigiScan monitoring. They were then stratified into either organic or psychogenic groups based on each of these modalities. These diagnoses were then compared to a final diagnosis obtained through additional testing. RESULTS: History and physical examination had a 95% sensitivity but only a 50% specificity in diagnosing organic ED. The accuracy rates of history and physical examination in diagnosing ED were 80% and 60%, respectively. CONCLUSIONS: A multifaceted comprehensive approach is required to evaluate fully and to diagnose ED.

Urothelial tumors of upper tract following treatment of primary bladder transitional cell carcinoma.

We studied, retrospectively, the incidence of upper tract urothelial tumors following the treatment of primary transitional cell carcinoma of the bladder in 638 patients. Subsequent tumor development was found in 20 patients (3.1%) with a mean latency interval between initial treatment of the bladder cancer and diagnosis of the upper urinary tract tumor of eighty months. We did not find a significant difference among treatment modalities on the incidence of upper tract occurrences. Other than carcinoma in situ, tumor stage was not an independent predictive variable.

Gleason's histologic grading as clinical prognostic marker in patients with advanced prostatic carcinoma.

We have found that the Gleason's histologic grading system is a good clinical marker to predict long-term response and prognosis in symptomatic Stage D-2 adenocarcinoma of the prostate. In this retrospective study, 56 cases were reviewed and correlated with bone scan, acid phosphatase, and symptomatology following bilateral orchiectomy.

Intracavernous pressure responses to physical and electrical stimulation of the cavernous nerve in rats.

OBJECTIVES: To better define the techniques of nerve-sparing prostate dissection that would result in preservation of erectile function, we characterize the effects of physical pressure on the prostate and cavernous nerve, electrical stimulation of the cavernous nerve, and pharmacologic manipulations on intracavernous pressure (ICP) in normal and diabetic rats. METHODS: Fischer-34 rats, both normal and diabetic, underwent dissections that isolated the cavernous bodies and cavernous nerves. Cavernous body pressures were characterized during surgical manipulation, during electrical stimulation of the cavernous nerves, and following papaverine hydrochloride injection. RESULTS: In normal rats, baseline cavernous pressures ranged from 5 to 15 cm H2O (mean 12.29). In diabetic rats, the baseline pressure was significantly lower (3 to 7.5 cm H2O). Lateral nerve displacement caused ICP to rise to approximately 35 cm H2O in normal rats, but only to 20 cm H2O in diabetic rats. Electrostimulation resulted in cavernous pressure increases of 10-fold from baseline in normal rats and sevenfold from baseline in diabetic rats. ICPs were not disturbed appreciably with nerve-sparing dissection techniques. Neurotomy resulted in declines in baseline cavernous pressures in all rats. Electrostimulation of the distal end of a severed nerve resulted in pressure rises to 50% of those observed in rats with intact cavernous nerves. Intracavernous papaverine injection before or after nerve stimulation masked subsequent (expected) pressure changes. CONCLUSIONS: A change in cavernous pressure is a sensitive indicator of cavernous nerve manipulation. Both cavernous pressure measurements and electrostimulation of cavernous nerves may aid surgeons during radical prostatectomy.

Relationship between contraction and relaxation in human and rabbit corpus cavernosum.

Although alterations in corporeal smooth muscle tone undoubtedly play an important role in the etiology of erectile dysfunction, the relationship between the degree of corporeal smooth muscle contraction and the magnitude of the observed relaxation response has never been quantitated. Thus, in vitro studies were conducted to examine the relationship between alpha 1-adrenergic contractility, and relaxations elicited by the clinically and physiologically relevant vasorelaxants, nitroglycerin, nitroprusside, and prostaglandin E1. Corporeal tissues strips were isolated from impotent and potent men, as well as sexually mature rabbits, and precontracted over a wide range of phenylephrine doses, prior to exposure of each tissue to the same dose of vasorelaxant. Plots of percent contraction versus percent relaxation revealed that the relationship between contraction and relaxation was accurately described by a first order linear equation, and characterized by an inverse relationship in all tissues studied, for all vasorelaxants examined. Statistical analysis indicated that the slope of the regression line was significantly greater than unity in all corporeal tissues obtained from patients with organic impotence; however, corporeal tissues obtained from patients with documented erections and from sexually mature rabbits had significantly lower slopes that were indistinguishable from unity. The existence of an inverse relationship between contraction and relaxation, even in the absence of organic disease, emphasizes the importance of the level of basal corporeal smooth muscle tone per se. These studies provide further evidence implicating heightened adrenergic tone as a significant etiologic factor in erectile dysfunction.