THIAZIN DYES 



338 



THYMONUCLEIC ACID 



due to flavin and that on alkalinization 

 this is replaced by a bluish fluorescence 

 which is known to be occasioned by the 

 presence of thiamine, itself identical 

 with vitamin B, or aneurin. 



See Cartesian diver technique of 

 Westenbrink, H. G. K., Enzymologia, 

 1940, 8, 97-107. Click, p. 395 thinks 

 that the technique of Schultz, A., At- 

 kin, L. and Frey, C. N., Ind. Eng. 

 Chem., Anal. Ed., 1942, 14, 35-39 based 

 on stimulation of yeast fermentation 

 by thiamine. 



Thiazin Dyes. A very useful group of dyes 

 for the histologist. The two benzene 

 rings are joined by =N— and — S— . 

 Examples : azure A, B and C, methylene 

 azure, methylene blue, methylene green, 

 methylene violet, new methylene blue 

 N, thionin, toluidin blue O. 



Thiazine Red R (CI, 225)— chlorazol pink 

 Y, rosophenine lOB — An acid mono-azo 

 dye employed especially as counterstain 

 for iron hematoxylin. 



Thiazole Dyes contain thiazole ring with 

 indamine as chroma tophore. Geranine 

 G, primalin, thioflavine S, and titan 

 yellow. All of these dyes appear to be 

 useful in fluorescence microscopy. Pick, 

 J., Zeit. f. wis. Mikr., 1935, 51, 338-351 

 refers to three of them. 



Thiazole Yellow, see Titan Yellow. 



Thioflavine S (CI, 816). An acid thiazole 

 dye used in fluorescence microscopy. 



Thionin (CI, 920)— Lauth's violet— Com- 

 mission Certified. An extremely useful 

 basic thiazin dye. See Tissue Baso- 

 philes, King's Carbol Thionin, etc. 



Thiourea. A derivative of urea with sul- 

 phur replacing oxygen. As means of 

 activating thyroid gland (Thomas, O. 

 L., Anat. Rec, 1944, 89, 461-469). 

 Effect on organ weights and plasma 

 proteins of the rat (Leathem, J. H., 

 Anat. Rec, 1944, 89, 540). 



Thomas, see Arginine Reaction. 



Thorium Dioxide is occasionally employed 

 as a vital stain for reticulo-endothelium. 

 Angermann, M. and Oberhof, K., Zeit. 

 f. Ges. Exp. Med., 1934, 94, 121-126 give 

 directions for its administration to rab- 

 bits and for determination of its dis- 

 tribution chemically, radiologically and 

 histologically. (Thorotrast) 



Thulium, see Atomic Weights. 



Thyme Oil N.F. VI. Sometimes misnamed 

 oil of origanum. Contains thymol, car- 

 vacrol, cymene, pinene, linalool and 

 bornyl acetate. It is said to be useful 

 for clearing celloidin sections. 



Thymol Blue. See Hydrogen Ion Indicators. 



Thymonucleic Acid is a type of desoxypen- 

 tose nucleic acid isolated from nuclei 

 of the thymus. Also called desoxyribo- 

 nucleic acid on DNA for short. {Feul- 

 gen or nucleal reaction for). Pass 



paraffin sections, fixed in equal parts 

 sat. aq. corrosive sublimate and ab- 

 solute alcohol, through xylol and al- 

 cohols to water. Place in a staining 

 jar containing normal HCl (82.5 cc. 

 HCl, sp. gr. 1.17-1.85 per liter of water) 

 at room temperature for 1 min. Trans- 

 fer to normal HCl, at 60°C. and there 

 hydrolyze for 4 min. Treat with the 

 fuchsin sulphurous acid reagent in a 

 staining jar for 3-I hr. (This reagent 

 is : One gram of basic fuchsin is dis- 

 solved in 100 cc. of distilled water with 

 the aid of a little heat. The solution is 

 filtered while still warm and 20 cc. of 

 normal HCl is added to the filtrate. The 

 resulting fluid is then cooled and 1 

 gm. dry sodium bisulfite (NaHSOj) is 

 added. Then, after standing for about 

 24 hrs., the reagent is ready for use and 

 should have a pale straw color.) Pass 

 through a series of 3 jars, each contain- 

 ing a solution made by adding 10 cc. of a 

 molecular solution of sodium bisulfite 

 (i.e., 104 grams per liter) to 200 cc. of 

 tap-water, allowing 1^ min. in each and 

 agitating frequently. Wash in tap 

 water for 5 min., dehydrate, clear and 

 mount in balsam. Thymonucleic acid 

 is colored purple or violet and color 

 holds (Cowdry, E. V., Science, 1928, 

 68,40-41). Collected references (Milo- 

 vidov, P., Protoplasma, 1938, 31 (2), 

 246-266) ; technique for plant tissues 

 (Whitaker, T. W., Stain Techn., 1939, 

 14, 13-16). A more recent account is 

 given by Stowell, R. E., Stain Techn., 

 1945, 20, 45-58. Specificity has been 

 considered by Dodson, E. O., Stain 

 Techn., 1946, 21, 103-105. See Bauer- 

 Feulgen stain for Glycogen. 



Dr. A. R. Gopal-Ayengar of the 

 Tata Memorial Hospital, Bombay has 

 supplied details of a modification of 

 the Feulgen technique by Rafalko, 

 J. S., Stain Techn., 1946 21, 91-93. In- 

 stead of using HCl and sulphites, as in 

 the usual method, Rafalko directly 

 charges both basic fuchsin and the 

 bath water with SO2 gas, using A'^ HCl 

 only for the necessary process of hy- 

 drolysis. By this method, he claims to 

 have been able to stain diffuse and small 

 chromosomes, which give negative 

 results with conventional procedure. 

 Three types of organisms were tested: 

 (1) Various small, endosome -containing 

 amoebae; (2) oocytes of parasitic wasps, 

 Habrobracon; and (3) the yeasts Sac- 

 charomyces cerevisiae and S. carlsber- 

 gensis. Fix smears for 2-20 min. 

 Wash in water 20 min. and in aq. dest. 

 20 min. A'^ HCl room temperature, 

 2 min. N HCl at 60°C., 8-10 min. 

 Rinse in A'" HCl at room temperature. 

 Rinse in aq. dest.. Sulphurous acid, 



