The immunosuppressive agent FK506 prevents subperineurial degeneration and demyelination on ultrastructural and functional analysis.

Several kinds of injury models, such as crush, transection and graft repair have been well studied in terms of neuroprotective effect of FK506. However, definitive experimental studies are lacking on focal degeneration or ischemia. In the present study, our goal was to investigate the effect of FK506 on functional recovery of the sciatic nerve after focal ischemia, produced by stripping of the epineurial vessels. A total number of 48 Wistar rats were used for this purpose and divided into four groups (control, sham-operated, FK506-treated, and Vehicle-treated). Sciatic nerves were approached by femoral and gluteal muscle splitting. Then, epineurial vessels around the sciatic nerve were stripped in the FK506-treated and Vehicle-treated groups. After operation, 5mg/kg/day FK506 administration was initiated by subcutaneous injection until animal sacrifice. The same volume of saline was administrated to the vehicle-treated group. The functional and sensory recoveries were tested by walking pattern analysis and pinch test in every postoperative week. The animals were sacrificed in the end of the fourth postoperative week and sciatic nerve samples were harvested and processed for electron microscopic evaluation. Our data revealed that FK506 administration showed beneficial effect on subperineurial degeneration/demyelinization from functional, sensorial, and ultrastructural points of view. The sciatic nerve samples in the FK506-treated group had several remyelinated fibers compared to the vehicle-treated group. Our literature searches revealed that FK506 administration has not, to our knowledge, been studied in focal ischemic degeneration produced by stripping of the epineurial vessels.

The incidence of accessory navicular bone types in Turkish subjects.

Accessory ossicles are the skeletal variations of the ankle and foot that can cause painful syndromes. The accessory navicular bone is one of the most common accessory ossicle of the foot (4-21%) and is also known as os tibiale, os tibiale externum and os naviculare secundarium. This bone can be adjacent to the posteromedial tuberosity of the navicular bone or can be separated and may cause various diseases in the foot and mimic fractures of foot bones. The aim of this study was to document a detailed investigation of incidence and types of accessory navicular bones of Turkish subjects according to sex in both extremities. The accessory navicular bone was detected (11%) via the posterior-anterior radiographs of 650 subjects in the radiological examination. The incidences of accessory navicular bones were identified as 6.1-4.9% in female and male participants. Accessory navicular bones were classified into three groups as Type I, Type II and Type III and the incidences of these bones were determined as 3.3, 3.1, 4.6%, respectively. Each group was also divided into subgroups. The incidences of the subgroups are as Type Ia 0.6%, Type Ib 1.5%, Type Ic 1.2%, Type IIA/a 0.8%, Type IIA/b 0.4%, Type IIA/c 0%, Type IIB/a 1.1%, IIB/b 0.3%, IIB/c 0.5%, Type IIIa 1.5%, Type IIIb 1.4%, Type IIIc 1.7%. Finally, the types of accessory navicular bones were discussed and the imaging modalities for diagnosis were presented.