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The author conducted experimental studies of active flexion/passive extension of the IP・MP joints of thumbs fitted with a Dynamic Extension Splint by using and not using rubber band traction apparatus, and evaluated the electromyographical wave pattern and electromyographic muscle activities of the EPL and FPL of eight healthy male adults. Statistically significant differences were not detected between the experimental (passive extension using rubber band traction apparatus) and control (active extension) groups. The authors concluded that there is a limitation of the effectiveness of active flexion/passive extension of the IP・MP thumb joints conducted with a rubber band traction apparatus as a postoperative early motion therapy for EPL tendon rupture., 関節装具装着時のIP/MP関節の長母指伸筋運動パターンについて検討した。男性健常者8名(平均21.75±0.43歳)を対象とした。伸展ダイナミックスプリントを装着した親指のIP/MP関節の屈曲/伸展運動を、筋電図を用いて評価した。ゴムバンド牽引装具を装着した場合の母指のIP/MP関節の伸展を他動伸展とした。長母指伸筋活動の強度を、自動屈曲/他動伸展(実験群)と、自動屈曲/自動伸展(対照群)とで比較した。長母指伸筋活動の基準値として、長母指屈筋活動も測定した。実験群の他動伸展と対照群の自動伸展に統計学的有意差は認められなかった。本研究結果から、長母指伸腱断裂の術後早期運動療法として用いるゴムバンド牽引装具の有効性には限界があると考えられた。

The filum terminale (FT) is a potential source of ependymal cells for transplantation. The present study was performed to clarify the characteristics of ependymal cells of the central canal (CC) of the FT in rats. The FT was a thin strand continuous with the conus medullaris (CM), a caudal end of the main spinal cord, situated at the L3-4 level in adult rats. The border between the CM and FT was not visible, but could be defined as the site where the strand was as thin as its more caudal segment. While the CM contained an appreciable amount of white and grey matter associated with the CC at its center, the FT had no or only a negligible amount of such spinal cord parenchymal tissue. The FT was tracked ca. 4 cm from the site defined above to the level of S4-5 in adult rats. The rostral part of the FT (FTI) included within the cauda equina is exposed to cerebrospinal fluid, whereas the more caudal part (FTE) was surrounded by a dense layer of connective tissue. Almost all ependymal cells were immunostained for Sox2, Sox9, FoxJ1, and CD133, generally recognized immunochemical markers for ependymal cells of the CC in the spinal cord. Ependymal cells of the CC of FT exhibited almost the same structural and immunohistochemical characteristics as those of the CC of the main spinal cord. Ependymal cells of FTI covered by a thin layer of connective tissue are considered appropriate for transplantation.

Bone marrow stromal cells (BMSCs) have been studied for the treatment of spinal cord injury (SCI). In previous studies, we showed that the transplantation of BMSCs, even though they disappeared from the host spinal cord within 1-3 weeks after transplantation, improved locomotor behaviors and promoted axonal regeneration. This result led to the hypothesis that BMSCs might release some neurotrophic factors effective for the treatment of SCI. The present study examined this by injecting the conditioned medium (CM) of BMSCs to treat SCI in rats. The spinal cord was contusion-injured, followed immediately by continuous injection for 2 weeks of the CM of BMSCs through the cerebrospinal fluid via the 4th ventricle using an Alzet osmotic pump. Locomotor behaviors evaluated by the Basso-Beattie-Bresnahan score were markedly improved in the CM-injection group, compared with the control group, at 1 to 4 weeks post-injection. The contusion-injured site of the spinal cord was identified as an astrocyte-devoid area, which contained no astrocytes but was filled with collagen matrices and empty cavities of various sizes. Collagen matrices contained type I collagen and laminin. Numerous axons extended through the collagen matrices of the astrocyte-devoid area. Axons were surrounded by Schwann cells, exhibiting the same morphological characteristics as peripheral nerve fibers. The density of axons extending through the astrocyte-devoid area was higher in the CM-injection group, compared with the control group. CM injection had beneficial effects on locomotor improvements and tissue repair, including axonal regeneration, meaning that the BMSC-CM stimulated the intrinsic ability of the spinal cord to regenerate. Activation of the intrinsic ability of the spinal cord to regenerate by the injection of neurotrophic factors such as BMSC-CM is considered to be a safe and preferable method for the clinical treatment of SCI.