渡部 昌実

We investigated the usefulness of one-stage urethroplasty by the parameatal foreskin flap method (OUPF procedure), which is useful for repairing all types of hypospadias. Between June 1992 and March 2001, the OUPF procedure was performed on 18 patients with hypospadias: 10 patients with distal and 8 with proximal hypospadias. The follow-up periods ranged from 33-75 months, with an average of 52 months. The duration of surgery, the catheter indwelling period, and the postoperative complications of each patient were analyzed. The median age of the patients at the time of surgery was 3 years and 8 months. The length of surgery for OUPF II ranged from 150-230 min (average 186 min), and from 190-365 min (average 267 min) for OUPF IV. Postoperative complications were confirmed in 3 of the 18 patients (16.6%). Two patients had fistulas, and one had a meatal regression. The fistulas were successfully closed by the simple multilayered closure method. After adopting DuoDerm dressings instead of elastic bandages for protection of the wound, no fistulization occurred. DuoDerm dressings are useful in the healing of wounds without complications. To date, the longest follow-up period has been 75 months, and during that time there have been no late complications such as urethral stenosis or penile curvature. OUPF is a useful method in the treatment of hypospadias with a low incidence of early and late complications.

Dynamin is a protein essential to endocytosis. Dynamin 2, a dynamin isoform, is expressed most intensely in testicular tissue; however, precise localization has never been studied. Therefore, we investigated the expression of dynamin 2 in rat testicular tissue using immunohistochemical methods, and discuss here the physiological function of this protein. Testicular tissues were obtained from Wistar rats at 10, 21 and 63 days of age. Immunohistochemistrical examination and Western blot analysis were conducted using dynamin 2 specific antibody. Western blot analysis showed that expression in 21- and 63-day-old rats was more intense than that in 10-day-old rats. Dynamin 2 expression was observed using immunohistochemical method in the seminiferous tubules of all rats. In the 63-day-old rats, the expression was intense, especially in spermatids in the earlier maturation stages and in spermatocytes, and was observed in Sertoli cells. However, in spermatids, the expression gradually declined as spermatids matured to spermatozoa. In the 21-day-old rats, the expression was evident in spermatocytes and Sertoli cells, but that in the 10-day-old rats was weak. Intense expression of dynamin 2 during spermatogenesis suggests that this protein plays an important role in this process.

Testicular Sertoli cells highly express dynamin 2 and amphiphysin 1. Here we demonstrate that dynamin 2 is implicated in phosphatidylserine (PS)-dependent phagocytosis in Sertoli cells. Immunofluorescence and dual-live imaging revealed that dynamin 2 and amphiphysin 1 accumulate simultaneously at ruffles. These proteins are specifically bound in vitro. Over-expression of dominant negative dynamin 2 (K44A) inhibits liposome-uptake and leads to the mis-localization of amphiphysin 1. Thus, the cooperative function of dynamin 2 and amphiphysin 1 in PS-dependent phagocytosis is strongly suggested.