清水 一彦

Several complications may occur following iliac bone grafting, one of the common sites for autologous bone harvesting. Of these, it is difficult to localize the damage in neurological complications due to the presence of several nerves in a similar distribution area with variations among individuals. To minimize these complications, conventional clinical anatomical studies using normal human cadavers have estimated the theoretical neurological damage area corresponding to the surgical intervention area. We report a case of neuromuscular damage in a 93-year-old woman who had an iliac crest defect after a bone graft, based on the virtual and physical dissections with histological confirmations.In this study, the patient was confirmed to have severe neuromuscular complications with major complications including a hernia protruding through the iliac defect. One of the two ilioinguinal nerves was extracted with the hernia sac through the iliac defect, and its distal part was completely damaged. The iliohypogastric nerve, which was far from the defect foramen, also showed remarkable fibrosis and demyelination, affected by the degeneration of the transversus abdominis muscles.The present anatomical findings show that the area of eventual neuromuscular damage should be estimated to larger than the conventionally predicted area of direct nerve damage, which is usually concomitant with the surgical intervention area.

N-methyl-N-nitrosourea (MNU) is known to cause apoptosis of photoreceptor cells and changes in retinal pigment epithelium (RPE). However, the changes in choriocapillaris, which nourishes photoreceptor cells by diffusing tissue fluid through RPE, have not been reported in detail. Therefore, we studied the ultrastructural transformation in and around the choriocapillaris to characterize the interdependence between choriocapillaris and surrounding tissue components in a mouse model. Seven-week-old male C57BL/6 mice were given a single intraperitoneal injection of MNU (60 mg/kg of body weight). Perfusion-fixed eyeballs were examined chronologically using immunohistochemistry and electron microscopy until the photoreceptor cells were lost. Sequential ultrastructural changes were observed in photoreceptor cells, RPE, Bruch's membrane, choriocapillaris, and choroidal melanocytes after an MNU injection. The lumens of the choriocapillaris narrowed following dilation, and the vascular endothelium showed structural alterations. When the photoreceptor cells were completely lost, the choriocapillaris appeared to be in a recovery process. Our results suggest that transport abnormality through Bruch's membrane and structural changes in the choroid might have influenced the morphology of choriocapillaris. The thin wall of the choriocapillaris appears to be the cause of the vulnerability with its altered morphology.

日本産ジョロウグモ（Nephila clavata）の牽引糸遺伝子のcDNAをクローニングし、その塩基配列を初めて報告した。塩基配列から推定される日本産ジョロウグモ牽引糸タンパク質のアミノ酸配列をカイコのフィブロインH鎖や他のクモ牽引糸のものと比較した。牽引糸の繰り返し配列においてAn、（GA）nやGGX配列など共通の特徴を確認できた。クモ牽引糸タンパク質の繰り返し配列のコドン使用頻度をカイコのH鎖フィブロインと比較すると、同様の傾向があった。しかしながら、親水性と疎水性の分布は両者で大きな違いが見られた。引張り強度試験では、日本産ジョロウグモ牽引糸がカイコ繭糸よりも明らかに強いことが分かった。これらのことから、クモ糸を吐くカイコを作出してカイコH鎖フィブロインをクモ牽引糸タンパク質と置き換えること、あるいは両者の混合糸を作らせることにより、糸の強さや性状の異なる新しいシルクの創出が期待される。