Dose-dependent protective effect of sildenafil citrate on testicular injury after torsion/detorsion in rats.

This experiment was designed to investigate the effect of sildenafil citrate on testicular injury after unilateral testicular torsion/detorsion (T/D). Thirty-seven adult male Wistar albino rats were divided into four groups: sham operated group (group 1), T/D+ saline (group 2), T/D+ 0.7 mg sildenafil citrate (group 3) and T/D+ 1.4 mg sildenafil citrate (group 4). Testicular torsion was created by rotating the right testis 720° in a clockwise direction for 2 h in other groups, except for group 1, which was served as sham group. The level of GSH (P < 0.05) in the testis in the group 2 were significantly lower (P < 0.05) and the levels of MDA and NO (P < 0.01 for both) in the testis were significantly higher when compared with those of the group 1. Administration of low dose sildenafil citrate prevented the increases in MDA and NO levels and decreases in GSH values induced by testicular torsion. However, administration of high dose sildenafil citrate did not have any effect on these testicular tissue parameters (P > 0.05). Also, mean values of seminiferous tubules diameters, germinal cell layer thicknesses and mean testicular biopsy score were significantly better in group 3 than groups 2 and 4. These results suggest that T/D injury occurred in testis after unilateral testicular T/D and that administration of low dose sildenafil citrate before detorsion prevents ischemia/reperfusion cellular damage in testicular torsion. Sildenafil citrate probably acts through reduction of reactive oxygen species and support antioxidant enzyme systems.

A polyethylene-high proportion hydroxyapatite implant and its investigation in vivo.

An implant from hydroxyapatite and polyethylene (HA+PE) composite was investigated for the usability in large bone defects. With this aim, the implants were manufactured in blocks by hot compacting the mixture of 80% HA and 20% PE weight ratio. Powders were machined in a lathe in the dimensions of diaphysis of the radius of the mongrel dogs. Then a defect, 1.5 cm in length, was made in the diaphysis of the radius with an operation performed under general anaesthesia in 16 healthy mongrel dogs. The defects were filled with implant as a block. The dogs were observed radiologically in 15-day intervals and examined clinically in certain intervals. The bone samples were taken out from four dogs for the histopatological examinations at the end of the 2nd, 4th, 6th and 12th months, respectively. Clinical examinations indicated the occurrence of slight lameness in all cases at the first month of experiment, but lameness completely disappeared in a further examination. Progressive resorption and new bone formation began in the implants from the first month, but complete resorption was not observed in any case at the end of 12-month period. SEM and optical microscope examinations revealed fibroblast cell with its clear cytoplasmic extensions and osteoblast cells in endosteum in the inner region. Bone formation increasing and extending to the pores of implant in time and blood vessels with lamellar structure and Haversian system were observed. As a result, it was indicated that HA+PE composite implants could be applied with confidence and are useful in treatment of large bone defects in long bone of dogs.