Experimental model of human corpus cavernosum smooth muscle relaxation

PURPOSE: To describe a technique for en bloc harvesting of the corpus cavernosum, cavernous artery and urethra from transplant organ donors and contraction-relaxation experiments with corpus cavernosum smooth muscle. MATERIALS AND METHODS: The corpus cavernosum was dissected to the point of attachment with the crus penis. A 3 cm segment (corpus cavernosum and urethra) was isolated and placed in ice-cold sterile transportation buffer. Under magnification, the cavernous artery was dissected. Thus, 2 cm fragments of cavernous artery and corpus cavernosum were obtained. Strips measuring 3 x 3 x 8 mm3 were then mounted vertically in an isolated organ bath device. Contractions were measured isometrically with a Narco-Biosystems force displacement transducer (model F-60, Narco-Biosystems, Houston, TX, USA) and recorded on a 4-channel Narco-Biosystems desk model polygraph. RESULTS: Phenylephrine (1µM) was used to induce tonic contractions in the corpus cavernosum (3 - 5 g tension) and cavernous artery (0.5 - 1g tension) until reaching a plateau. After precontraction, smooth muscle relaxants were used to produce relaxation-response curves (10-12M to 10-4 M). Sodium nitroprusside was used as a relaxation control. CONCLUSION: The harvesting technique and the smooth muscle contraction-relaxation model described in this study were shown to be useful instruments in the search for new drugs for the treatment of human erectile dysfunction.

The isolated gamma probe technique for sentinel node penile carcinoma detection is unreliable

PURPOSE: Penile carcinoma is a common disease in northeast Brazil. This paper shows the results of the use of isolated gamma probe and discusses the incidence of false negative rates. MATERIALS AND METHODS: From July 2000 to September 2003, 27 newly diagnosed penile carcinoma patients (T1, T2, N0) were included in this prospective study. The isolated gamma probe technique uses the sodium phytate technetium as a tracer and inguinal scanning with probe and after identified the lymph node it is removed. Lymphadenectomies were performed for positive inguinal lymph nodes metastasis. RESULTS: There were 27 patients (mean age 59.6). Follow up was 37 months. Patients from country were 72 percent and illiterate or semi-illiterate were 56.7 percent. The tumors were mostly located in the glans (81.4 percent). They were T1, 52 percent and T2, 48 percent. 81.4 percent of the patients underwent partial penectomy, and 18.6 percent underwent postectomy and excision with wide margins. In 48 percent of the patients, the highest radioactive count rate was located on the left side, while in 41 percent was located on the right side. Only one patient had a positive pathological lymph node metastasis at the moment of the surgery. Additionally 3 patients became inguinal lymph node positive at the follow up. This date yielded a sensibility rate of 25 percent and a false-negative rate of 42.8 percent. CONCLUSION: Isolated gamma probe technique for sentinel node penile carcinoma has a very low sensibility and a high false negative rate. Therefore it is highly advisable the addition of others methods such as lymphoscintigraphy, vital blue, ultrasonography and so on. The isolated gamma probe technique for sentinel node penile carcinoma detection is unreliable.