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|Section2= |Section3= }} Haematoxylin, hematoxylin, Natural Black 1, or C.I. 75290 is a compound extracted from the heartwood of the logwood tree.〔Cooksey 2010〕 Hematoxylin is a basic / positive compound that binds to and forms salts with acidic, or basophilic, compounds containing negative charges (such as DNA and RNA which are acidic/negative because the nucleic acid building blocks that come off the phosphate backbone are negatively charged) and stains them dark blue or violet. Haematoxylin and eosin together make up haematoxylin and eosin stain, one of the most commonly used stains in histology. This type of stain is a permanent stain as opposed to temporary stains (e.g. iodine solution in KI). Another common stain is phosphotungstic acid haematoxylin, a mix of haematoxylin with phosphotungstic acid. When oxidized it forms haematein, a compound that forms strongly coloured complexes with certain metal ions, the most notable ones being Fe(III) and Al(III) salts. Metal-haematein complexes are used to stain cell nuclei prior to examination under a microscope. Structures that stain with iron- or aluminium-haematein are often called basophilic, even though the mechanism of the staining is different from that of staining with basic dyes. In the early 1970s and in 2008, there were shortages of haematoxylin due to interruptions in its extraction from logwood. The price of the compound increased, affecting the cost of diagnostic histopathology, and prompted a search for alternative nuclear stains. Before the use of any alternatives became firmly established, haematoxylin returned to the market, though at a higher price, and resumed its place in histopathology. Several synthetic dyes have been recommended as replacements, notably celestine blue (CI 51050), gallocyanine (CI 51030), gallein (CI 45445) and eriochrome cyanine R (also called chromoxane cyanine R and solochrome cyanine (CI 43820). All four have Fe(III) as the mordant. Another alternative is the aluminium complex of oxidized brazilin, which differs from haematoxylin by only one hydroxyl group. ==Staining solutions== These stains are commonly employed for histological studies. The mordants used to demonstrate nuclear and cytoplasmic structures are alum and iron, forming lakes or coloured complexes (dye-mordant-tissue complexes), the colour of which will depend on the salt used. Aluminium salt lakes are usually coloured blue-white, whereas ferric salt lakes are coloured blue-black. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「haematoxylin」の詳細全文を読む スポンサード リンク
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