【はじめに、目的】

超高齢社会を迎えた本邦では，フレイルが原因で要介護状態に陥る高齢者の数は増加することが明らかとなっており，その対策は喫緊の課題となっている．基本チェックリスト（KCL）は，IADL，運動機能，栄養状態，口腔機能，閉じこもり，認知機能，うつ症状など多様な機能低下を検出し総合的に心身の脆弱性を把握することが可能な評価ツールであり，フレイルを判別する妥当性がこれまでに数多く報告されている．一方，フレイルは後期高齢者においてその該当者が多いとされているが，前期高齢者にも少なからず存在することから，フレイル対策としての介入戦略は年代別に異なる可能性が高い．本研究では，フレイル高齢者のKCL該当項目が前期高齢者と後期高齢者の間で異なるのか否かについて検討し，年代の異なるフレイル高齢者のKCL該当項目の特徴を明らかにすることを目的とした．

【方法】

対象は，平成23年～25年の3年間で長崎市が実施した「二次予防対象者把握事業」におけるKCL全戸配布において返信があった59,290名の内，KCL25項目中8項目以上に該当したフレイル高齢者10,085名（平均年齢77.4±6.8歳，男性4,178名，女性5,907名）とした．そして，男女別に対象者を前期高齢者（65～74歳）と後期高齢者（75歳以上）に分け，KCLの各項目についてカイ二乗検定を用いて比較した．

【結果】

男性における前期高齢者は1,575名（37.7％），後期高齢者は2,603名（62.3％）であり，女性における前期高齢者は1,960名（33.2％），後期高齢者は3,947名（66.8％）であった．男性においてKCL各項目を前期高齢者と後期高齢者の間で比較した結果，前期高齢者では項目5，11，21の該当割合が後期高齢者に比べ有意に高く，後期高齢者では項目1，2，6，7，10，14，16，17の該当割合が前期高齢者に比べ有意に高かった．一方，女性の前期高齢者では項目9，11，14，15，21，22，23，25の該当割合が後期高齢者に比べ有意に高く，後期高齢者では項目1，2，3，4，5，6，7，8，10，16，17，19，20の該当割合が前期高齢者に比べ有意に高かった．

【結論】

フレイルに該当した前期高齢者では，男女ともに低栄養やうつ症状に関連する項目に該当している者の割合が高くなり，加えて，男性ではIADL，女性では転倒既往や口腔機能に関連する項目の該当割合が高かった．一方，後期高齢者では男女ともにIADL，運動機能，閉じこもりに関連する項目に該当している者の割合が高くなり，加えて，男性では口腔機能，女性では認知機能に関連する項目の該当割合が高かった．したがって，フレイル対策としての介入戦略は男女ともに前期高齢者と後期高齢者で異なる可能性が示唆された．

【倫理的配慮、説明と同意】

本研究では長崎市が二次予防対象者把握事業で実施した自記式アンケートの匿名化された（特定の個人を識別できない）データを研究目的で二次分析しており，データの研究への活用については長崎市から承認を得ている．

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Astrocytes regulate neuronal excitability by maintaining ion homeostasis and secreting neuroactive substances. We previously showed that blockade or expressional knockdown of inwardly rectifying potassium (Kir) 4.1 channels elevate BDNF expression in astrocytes (Int. J. Mol. Sci., 19, 3313, 2018). In order to explore the neural factors influencing on the Kir4.1-BDNF system, we investigated the effects of acetylcholinergic agents on mRNA expression of Kir4.1 and BDNF in primary cultured astrocytes. Treatment of astrocytes with acetylcholine inhibited Kir4.1 expression and increased BDNF expression in a concentration-related manner. Both inhibition of Kir4.1 and enhancement of BDNF expression by acetylcholine were antagonized by mACh antagonist atropine, but not by nACh antagonist mecamylamine. In addition, inhibition of Kir4.1 expression by acetylcholine was significantly antagonized by the selective M₁ antagonist pirenzepine, which also inhibited acetylcholine-induced BDNF expression. The present results strongly suggest that acetylcholine inhibits Kir4.1 expression and increases BDNF expression via the activation of M₁ receptor in astrocytes.

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Nishiki-ishi is a kind of jasper and shows mixed bright red, yellow-brown, green, and black colors. It occurs in Tsugaru region, Aomori Prefecture Japan and has been used for ornaments. Most of the raw stones are usually collected at shingle beaches, and few outcrops of the jasper are found out. Therefore, the occurrence of Nishiki-ishi has not been reported in detail. To elucidate the formation process of Nishiki-ishi, we observed textures of the rocks and minerals by optical and electron microscopes, Raman spectroscopy and analyzed the chemical compositions of minerals by an electron micro-probe analyzer.

 Nishiki-ishi were collected from two localities: Aoiwa, Nakadomari-machi, Kita-Tsugaru and Tappi-zaki, Sotogahama, Higashi-Tsugaru, Aomori Prefecture, Japan. It mainly consists of mixtures of micro-crystalline and crypto-crystalline quartz, opal-CT and iron-containing minerals.

 Its colors are caused by iron-containing minerals; hematite (red), celadonite (green), goethite (yellow), siderite (yellow), pyrite (black), and marcasite (black). These iron-containing minerals, which exhibit needle-like or granular forms, are included as fine grains in quartz crystal and fill boundaries among the quartz crystals.

 The macroscopic structure of Nishiki-ishi is breccia-like or clastic. In the texture, breccia fragments show yellow or red colors, and green and black parts filled up the space between breccia fragments. Yellow-brown and red color parts of Nishiki-ishi have flamboyant and mosaic (jigsaw) textures, which consist of micro-quartz and optically length-slow type spherules of quartz. Black and green color parts are also composed of opal-CT, chalcedony, and micro-quartz. These features are considerable differences of quartz textures between in brecciated fragments and at the matrix among brecciated fragments. Nishiki-ishi was formed by silicification of volcanic rocks during volcanic activity. After the silicified rocks brecciated, quartz and chalcedony precipitated in the breccia.

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From the lower Pleistocene strata in Japan Sea borderland, the following four species of rock-boring bivalves were obtained; Hiatella arctica (Linnaeus), Zirfaea subconstricta (Yokoyama), Penitella gabbii (Tryon) and Nettastomella japonica (Yokoyama). All these species are now living around Japanese Islands. Such a high extant rate is probably due to their endolithic life style. The Nettastomella and the Penitella-Zirfaea associations are recognized by the combination of above mentioned species. The southern limit of the Nettastomella association living around northern Hokkaido was situated at central Honshu in early Pleistocene. This distributional pattern and the low diversity of associations are attributed to the colder climate in those age than in the recent.

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