Yasuo Kawanishi

Coexistence of Nitric Oxide Synthase, Tyrosine Hydroxylase and Vasoactive Intestinal Polypeptide in Human Penile Tissue–a Triple Histochemical and Immunohistochemical Study

Recently, nitric oxide (NO) has been believed to act as a neuronal messenger to mediate penile erection. In the present study using human penile tissue, we investigated the coexistence of neuronal NO synthase (NOS), tyrosine hydroxylase (TH) and vasoactive intestinal polypeptide (VIP) by a triple staining method using NADPH diaphorase (ND) staining, a specific histochemical marker of neuronal NOS, and immunohistochemical staining for TH and VIP. Numerous ND-positive nerve fibers and TH-containing fibers were seen in axon bundles, but their distributions were different. Only a few axons in the bundles showed VIP immunoreactivity. Abundant fine varicose nerve terminals innervating cavernous smooth muscles and deep and helicine arteries were observed. The proportion of fibers showing TH-immunoreactivity in ND-positive terminals in the cavernous space was about 25%, and that of VIP was about 40%. Vasoactive intestinal polypeptide may act as a coworker in these fibers both in cavernous trabeculae and around arteries, as about 40% of NOS-containing fibers also showed VIP immunoreactivity. The physiological significance of the colocalization of TH and NOS is unclear, and further studies are required to know the physiological significance of the colocalization of NOS and other neurotransmitters in penile tissue.

Penile revascularization surgery for arteriogenic erectile dysfunction: the long‐term efficacy rate calculated by survival analysis

Authors from Japan describe their results with penile revascularization in patients who had arteriogenic erectile dysfunction. They recommend that this type of surgery is most suited to younger patients, and suggested that attention be paid to the long‐term outcome and the long‐term adverse events.

Effect of moxisylyte hydrochloride on isolated human penile corpus cavernosum tissue

The effect of moxisylyte hydrochloride on isolated human penile corpus cavernosum tissue was investigated and compared with other a-adrenergic antagonists. Moxisylyte produced a concentration-dependent relaxation of a norepinephrine-induced (1 x 10(-5) M) contraction of the corpus cavernosum tissue. Pretreatment with 1 x 10(-6) M doses of moxisylyte reduced competitively the norepinephrine-induced contraction. The competitive effect of prazosin was strongest among four tested agents, followed by phentolamine, moxisylyte, and then yohimbine. The activity ratio for each antagonist is 2.4 for moxisylyte, as compared with 28.2 for prazosin, 6.7 for phentolamine, and 1.6 for yohimbine respectively. Moxisylyte hydrochloride is an agent with potential clinical and research uses capable of producing erection when injected intra-cavernously.

Feasibility of multi‐slice computed tomography in the diagnosis of arteriogenic erectile dysfunction

Objective To compare computed tomography (CT) angiography (CTA) obtained by multi‐slice CT (a new minimally invasive method) with the current standard of arterial imaging, digital subtraction angiography (DSA), in diagnosing arteriogenic erectile dysfunction (ED).

Variations of the internal pudendal artery as a congenital contributing factor to age at onset of erectile dysfunction in Japanese

Associate Editor

Is Erythropoietin Effective for Impotence in Dialysis Patients

A. Imagawa, Kidney Center, Takamatsu Red Cross Hospital, Bancho 4-1-3, Kagawa 760 (Japan) Dear Sir, Clinical use of erythropoietin (r-EPO) is one of the recent advances in the field of dialysis therapy. r-EPO increases the patient’s red cell count with a concomitant rise in blood viscosity. Increased blood viscosity does cause some adverse side effects such as hypertension and occlusion of the arteriovenous fistula [1, 2]. However, we observed a beneficial side effect, an increase in the circumference of the penis during sleep which may also be caused by the increase in blood viscosity. We measured maximum nocturnal penile tumescence in 4 patients (32, 37, 46, and 51 years old) receiving long-term hemodialysis before and after a course of r-EPO therapy. We measured nocturnal penile tumescence for 3 nights using an in-house erectometer [3]. All patients had sexual dysfunction before r-EPO therapy. Two complained of slight difficulty during sexual intercourse due to inadequate erection, and another patient complained of difficulty achieving ejaculation due to rapid detumes-cence during sexual intercourse. These 3 patients were able to achieve full erection after intracavernous papav-erine injection [4]. The 4th patient had not been able to achieve erection adequate for coitus for a 5-year period, and was also unable to achieve erection in a papaverine test. The penile-brachial index [5] of the 4 patients was within normal limits ( > 0.7). Before r-EPO therapy, the maximum increase in the circumference of the penis during sleep in each patients was 2,12,24, and 26 mm, and their hematocrit (Ht) counts were 14, 19, 20, and 19, respectively. After 3 months of r-EPO therapy, 3 patients subjectively reported an increase in sexual ability. In all 3 patients, both Ht and circumference increased significantly after therapy. However, in the 1 patient with impotence, no change in sexual ability was indicated by either subjective or objective evaluation. Also the increase in his Ht was slight (fig. 1). ΔNPT (mm) y 30 ⁄ 0Jr 10 20 30 40 Ht(7o) Fig. 1. Changes in the circumference and Ht before and after r-EPO therapy in hemodialysis patients. • = Before treatment; O = after treatment; NPT= nocturnal penile tumescence.

Three-dimensional CT cavernosography: reconsidering venous ligation surgery on the basis of the modern technology

Study Type – Therapy (case series) 
Level of Evidence 4

Effect of aldosterone on isolated human penile corpus cavernosum tissue

To clarify the physiological effects of aldosterone on human penile corpus cavernosum (hPCC) tissue, as aldosterone has a wider physiological action than just the maintenance of electrolyte balance, and there are mineralocorticoid receptors, i.e. aldosterone receptors, in hPCC tissue.

Retinal vascular findings and penile cavernosal artery blood flow

Authors from Japan attempt to correlate retinal vascular changes with cavernosal arterial blood flow. They studied patients with erectile dysfunction, but excluded patients with previous pelvic surgery, pelvic injury or diabetes. They found that penile changes can be anticipated from retinal vascular changes seen on fundoscopy.

Virtual cavernoscopy: a novel diagnostic tool for use in the corpus cavernosal lumen in patients with erectile dysfunction

Study Type – Diagnostic (case series)