Aim: As an attempt to clarify the molecular basis of castration-induced apoptosis, this study was undertaken to demonstrate the expression of caspase-1 in male accessory sex organs of rats. Methods and results: cDNA of rat caspase-1 was cloned by reverse transcription-polymerase chain reaction from the ventral prostates. The open reading frame predicts 402 amino acids, which shows more than 91% and 63 % identity to those of mouse and human, respec tively. Northern analyses demonstrated the presence of castration-induced up-regulation of the 1.6 kb transcript in the ventral prostate and the seminal vesicles. Finally, the authors demonstrated the caspase-1 transcripts in the epithelia of these tissues by in situ hybridization analyses. Conclusion: Castration induces the expression of caspase-1 tran scripts in the epithelia of ventral prostate and seminal vesicle. These observations suggest a possible role of caspase-1 in apoptosis in male accessory sex organs.

Objective: To treat vertebral fractures with posterior wall injury in the elderly, vertebral bone grafting is generally performed through a posterior transpedicular approach, combined with pedicle screw fixation. An autologous bone is ideal to treat this disorder. However, harvesting autologous bones from the elderly with osteoporosis is limited by the amount and quality of available autologous bone. Thus, we developed a bone-grafting substitute. The newly developed unidirectional porous β-tricalcium phosphate, with a porosity of 57% (UDPTCP; Affinos®, Kuraray Co., Ltd., Tokyo, Japan), is used in the bone-grafting procedure. This is the first report of UDPTCP used as an artificial bone graft in patients with an acute vertebral burst fracture.Materials and Methods: UDPTCP (mean: 4.2 g) was implanted through the pedicle, and posterior instrumentation was achieved with pedicle screws in five elderly patients. Resorption of UDPTCP and substitution with the autologous bone were evaluated on computed tomography (CT) and plain X-ray performed immediately and at 3, 6, and 12 months after the operation.Results: In case 1, the pedicle screws did not loosen, and UDPTCP was completely resorbed and replaced with the autologous bone at 3 postoperative months. In the other four cases, although the pedicle screws or the caudal part loosened because of osteoporosis, resorption of UDPTCP was observed at 3 postoperative months. At 6 postoperative months, progressive substitution with the autologous bone was confirmed, and at 12 postoperative months, formation of the good autologous bone was confirmed.Conclusion: This preliminary case series demonstrated that the newly developed UDPTCP shows good clinical potential as a bone-graft substitute for acute vertebral burst fractures in the elderly, including patients with osteoporosis.