Biomaterial Database

Tannic acid improves the visualization of the human erythrocyte membrane skeleton by freeze-etching. 1983

S Fujikawa

The effect of fixatives on the membrane skeleton underlying the human erythrocyte membrane was examined by freeze-etching. An anastomosing fibrillar network was readily observed on the protoplasmic surface of the erythrocyte membrane treated with tannic acid. Such structure was much less defined in unfixed membrane or membrane fixed with glutaraldehyde or glutaraldehyde followed by osmium tetraoxide. Tannic acid caused a marked increase in diameter of the fibrillar components of the membrane skeleton and of the protoplasmic surface particles of inside-out vesicles prepared by alkali treatment but did not affect the size of intramembranous particles seen on fracture faces nor the appearance of exoplasmic surfaces. The improved visualization of the membrane skeleton after treatment with tannic acid resulted from interactions between tannic acid and exposed membrane proteins.

UI	MeSH Term	Description	Entries
D009993	Osmium Tetroxide	(T-4)-Osmium oxide (OsO4). A highly toxic and volatile oxide of osmium used in industry as an oxidizing agent. It is also used as a histological fixative and stain and as a synovectomy agent in arthritic joints. Its vapor can cause eye, skin, and lung damage.	Osmic Acid,Acid, Osmic,Tetroxide, Osmium
D004910	Erythrocyte Membrane	The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.	Erythrocyte Ghost,Red Cell Cytoskeleton,Red Cell Ghost,Erythrocyte Cytoskeleton,Cytoskeleton, Erythrocyte,Cytoskeleton, Red Cell,Erythrocyte Cytoskeletons,Erythrocyte Ghosts,Erythrocyte Membranes,Ghost, Erythrocyte,Ghost, Red Cell,Membrane, Erythrocyte,Red Cell Cytoskeletons,Red Cell Ghosts
D005404	Fixatives	Agents employed in the preparation of histologic or pathologic specimens for the purpose of maintaining the existing form and structure of all of the constituent elements. Great numbers of different agents are used; some are also decalcifying and hardening agents. They must quickly kill and coagulate living tissue.	Fixative,Pickling Agents,Agents, Pickling
D005613	Freeze Etching	A replica technique in which cells are frozen to a very low temperature and cracked with a knife blade to expose the interior surfaces of the cells or cell membranes. The cracked cell surfaces are then freeze-dried to expose their constituents. The surfaces are now ready for shadowing to be viewed using an electron microscope. This method differs from freeze-fracturing in that no cryoprotectant is used and, thus, allows for the sublimation of water during the freeze-drying process to etch the surfaces.	Etching, Freeze
D005976	Glutaral	One of the protein CROSS-LINKING REAGENTS that is used as a disinfectant for sterilization of heat-sensitive equipment and as a laboratory reagent, especially as a fixative.	Glutaraldehyde,Cidex,Diswart,Gludesin,Glutardialdehyde,Glutarol,Korsolex,Novaruca,Sekumatic,Sonacide,Sporicidin
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D013634	Tannins	Polyphenolic compounds with molecular weights of around 500-3000 daltons and containing enough hydroxyl groups (1-2 per 100 MW) for effective cross linking of other compounds (ASTRINGENTS). The two main types are HYDROLYZABLE TANNINS and CONDENSED TANNINS. Historically, the term has applied to many compounds and plant extracts able to render skin COLLAGEN impervious to degradation. The word tannin derives from the Celtic word for OAK TREE which was used for leather processing.	Tannin
D047348	Hydrolyzable Tannins	Polymeric derivatives of GALLIC ACID that are esters of a sugar.	Ellagi-Tannins,Ellagitannins,Gallo-Tannins,Gallotannins,Pyrogallol Tannins,Ellagi Tannins,Gallo Tannins,Tannins, Hydrolyzable,Tannins, Pyrogallol