Micro-recanalization in a biodegradable graft for reconstruction of the vas deferens is enhanced by sildenafil citrate

This study investigated the effect of sildenafil citrate on micro-recanalization and neovascularization, which were previously demonstrated in a rat model using biodegradable grafts (BGs) for vas deferens reconstruction. A total of 24 male rats underwent bilateral vasectomy with removal of a 0.5-cm vasal segment and were randomly assigned to four groups. Groups 1 and 2 underwent immediate vasovasostomy. Groups 3 and 4 underwent interposition of a 0.5-cm BG in the vasal gap. Groups 1 and 3 were given 5 mg kg -1 day -1 oral sildenafil. Other groups were given placebo. Rats were housed with females 12 weeks postoperatively. Reconstructed vasal segments were harvested 16 weeks postoperatively and analyzed histologically. Fluid from the distal vasal stump was analyzed for motile sperm. Urine samples obtained 16 weeks postoperatively were analyzed for cGMP levels. cGMP levels in rats treated with sildenafil were significantly higher than in control rats. No pregnancies were sired by grafted groups. In all, 5/6 rats in group 1 and 3/6 rats in group 2 sired litters. No motile sperm were noted in the vasal fluid of the grafted groups. Motile sperm were noted in all rats in group 1 and in 5/6 rats in group 2. In addition, 29 and 4 microcanals were detected in the sildenafil and placebo groups, respectively (P = 0.023). No microcanal exceeded 3 mm in length. An average of 12 and 28 blood vessels per graft were noted in the placebo and sildenafil groups, respectively (P 0.0001). In conclusion, sildenafil enhances micro-recanalization and neovascularization in BG used for vas deferens reconstruction, but does not increase the microcanal length after 16 weeks

Early microrecanalization of vas deferens following biodegradable graft implantation in bilaterally vasectomized rats

We evaluated a biodegradable graft for reconstruction of rat vasa deferentia with long obstructed or missing segments. A total of 47 Sprague-Dawley rats underwent bilateral vasectomy and were divided into groups according to length of the vas deferens affected (0.5, 1, 1.5 cm). After 8 weeks, poly-(D,L-lactide) (PDLA) grafts were used to reconnect the vas deferens. Grafts and adjoining vasa deferentia were excised 8 and 12 weeks later and evaluated microscopically. At 8 weeks, microscopic changes included a robust inflammatory response around the grafts. All grafts were still intact but in the early stages of degradation. No microtubules, indicative of vas deferens recanalization, were identified. One specimen showed evidence of healing and neovascularization at the interface zone between the vas deferens and the graft. At 12 weeks, grafts were further degraded but still present. Microscopic evaluation showed decreased inflammation. Seven specimens showed neovascularization at the interface zone; two of these showed distinct epithelialized vas deferens microcanals at the graft edges. One specimen showed a microcanal spanning the entire 0.5-cm graft. A time period of 8 weeks is not ample enough for vas deferens regeneration in the setting of a biodegradable PDLA graft; however, early evidence of re-growth was seen at 12 weeks. A longer healing time should permit further biodegradation of the graft, as well as re-growth and possible eventual reconnection of the vas deferens, allowing passage of sperm. These findings suggest a potential role for biodegradable grafts in the reconstruction of vas deferens with long obstructed segments

Closed Timelike Curves and Holography in Compact Plane Waves

We discuss plane wave backgrounds of string theory and their relation to Goedel-like universes. This involves a twisted compactification along the direction of propagation of the wave, which induces closed timelike curves. We show, however, that no such curves are geodesic. The particle geodesics and the preferred holographic screens we find are qualitatively different from those in the Goedel-like universes. Of the two types of preferred screen, only one is suited to dimensional reduction and/or T-duality, and this provides a ``holographic protection'' of chronology. The other type of screen, relevant to an observer localized in all directions, is constructed both for the compact and non-compact plane waves, a result of possible independent interest. We comment on the consistency of field theory in such spaces, in which there are closed timelike (and null) curves but no closed timelike (or null) geodesics.Comment: 21 pages, 3 figures, LaTe

Nonfunctional Supernumerary Testis in a 26-Year-Old Man with Orchalgia

Polyorchidism is a rare phenomenon, with 47 histologically confirmed cases and 77 total reported cases. In most patients, it is an incidental finding or an asymptomatic scrotal mass. More than half of histologically confirmed supernumerary testes have been reported to have the potential for sperm production. We report a case of a man with symptomatic left scrotal pain who was found to have a nonfunctional supernumerary testis in his left hemiscrotum

Micro-recanalization in a biodegradable graft for reconstruction of the vas deferens is enhanced by sildenafil citrate

This study investigated the effect of sildenafil citrate on micro-recanalization and neovascularization, which were previously demonstrated in a rat model using biodegradable grafts (BGs) for vas deferens reconstruction. A total of 24 male rats underwent bilateral vasectomy with removal of a 0.5-cm vasal segment and were randomly assigned to four groups. Groups 1 and 2 underwent immediate vasovasostomy. Groups 3 and 4 underwent interposition of a 0.5-cm BG in the vasal gap. Groups 1 and 3 were given 5 mg kg -1 day -1 oral sildenafil. Other groups were given placebo. Rats were housed with females 12 weeks postoperatively. Reconstructed vasal segments were harvested 16 weeks postoperatively and analyzed histologically. Fluid from the distal vasal stump was analyzed for motile sperm. Urine samples obtained 16 weeks postoperatively were analyzed for cGMP levels. cGMP levels in rats treated with sildenafil were significantly higher than in control rats. No pregnancies were sired by grafted groups. In all, 5/6 rats in group 1 and 3/6 rats in group 2 sired litters. No motile sperm were noted in the vasal fluid of the grafted groups. Motile sperm were noted in all rats in group 1 and in 5/6 rats in group 2. In addition, 29 and 4 microcanals were detected in the sildenafil and placebo groups, respectively (P = 0.023). No microcanal exceeded 3 mm in length. An average of 12 and 28 blood vessels per graft were noted in the placebo and sildenafil groups, respectively (P 0.0001). In conclusion, sildenafil enhances micro-recanalization and neovascularization in BG used for vas deferens reconstruction, but does not increase the microcanal length after 16 weeks.This article is from Asian Journal of Andrology 12 (2010): 814, doi: 10.1038/aja.2010.55. Posted with permission.</p

Early microrecanalization of vas deferens following biodegradable graft implantation in bilaterally vasectomized rats

We evaluated a biodegradable graft for reconstruction of rat vasa deferentia with long obstructed or missing segments. A total of 47 Sprague-Dawley rats underwent bilateral vasectomy and were divided into groups according to length of the vas deferens affected (0.5, 1, 1.5 cm). After 8 weeks, poly-(D,L-lactide) (PDLA) grafts were used to reconnect the vas deferens. Grafts and adjoining vasa deferentia were excised 8 and 12 weeks later and evaluated microscopically. At 8 weeks, microscopic changes included a robust inflammatory response around the grafts. All grafts were still intact but in the early stages of degradation. No microtubules, indicative of vas deferens recanalization, were identified. One specimen showed evidence of healing and neovascularization at the interface zone between the vas deferens and the graft. At 12 weeks, grafts were further degraded but still present. Microscopic evaluation showed decreased inflammation. Seven specimens showed neovascularization at the interface zone; two of these showed distinct epithelialized vas deferens microcanals at the graft edges. One specimen showed a microcanal spanning the entire 0.5-cm graft. A time period of 8 weeks is not ample enough for vas deferens regeneration in the setting of a biodegradable PDLA graft; however, early evidence of re-growth was seen at 12 weeks. A longer healing time should permit further biodegradation of the graft, as well as re-growth and possible eventual reconnection of the vas deferens, allowing passage of sperm. These findings suggest a potential role for biodegradable grafts in the reconstruction of vas deferens with long obstructed segments.This article is from Asian Journal of Andrology 11 (2009): 373, doi: 10.1038/aja.2008.8. Posted with permission.</p