SUDAN BLACK B. 



SULFHYDRYL GROUPS 



bedded in gelatin or not. 6-10 microns 

 thick. Transfer to aq. dest. and then 

 into 50% diacetin agitated 30 sec. To 

 make stain, add excess Sudan Black B 

 (I.G.F.) to equal volumes of diacetin 

 and aq. dest., incubate at 55°C. for 2 

 days. Cool. Before use filter off 

 amount required. Stain 15 micron sec- 

 tions 2 hrs. If speed is necessary warm 

 in paraffin oven. 50% diacetin 30 sec. 

 Counterstain with carmalum. Place 

 in dish of water with care making sec- 

 tions "spin on surface and flatten." 

 Float on to slide and mount in Apathy's 

 medium. Nuclei red, lipids including 

 myelin black (Leach, E. H., J. Path. & 

 Bact., 1938, 47, 635-637). Diacetin is 

 glycerol diacetate introduced as solvent 

 for scharlach R by Gross (W., Zeit., 

 wiss. Mikr., 1930, 47, 64). Since Leach 

 does not specify what Apathy's medium 

 is, it is suggested that temporary 

 mounts be made in glycerin. 



2. For myelin (Lison, L. and Dag- 

 nelie, J., Bull. d'Histol. AppL, 1935, 

 12, 85-91). To stain lipoid granules in 

 leucocytes. Dry blood smear and fix 

 in methyl alcohol, 30 sec. Stain in a jar 

 with sat. Sudan black B in 70% alcohol, 

 30 min. Rinse in water and wash 1 min. 

 in 70% alcohol to remove deposit. 

 Counterstain with sat. alcoholic eosin in 

 70% alcohol, 30 sec. Wash and stain 

 in sat. aq. methylene blue 3 min. Rinse, 

 blot dry and examine with oil immersion. 

 Lipoid granules, deep black; nuclei, 

 blue; and erythrocytes, red. (Sheehan, 

 H.L ,J. Path. & Bact., 1939, 49,580-581). 



Sudan Black Bi as a bacterial fat stain. 

 Sat. sol. of Sudan black B (Nat. Aniline 

 and Chemical Co.) in 70% alcohol, or 

 in ethylene glycol stains fat bodies in 

 bacteria deep blue black (Hartman, T. 

 L., Stain Techn., 1940, 15, 23-28). 



Sudan Blue G, Brown 5 B, Corinth B, as fat 

 stains (Lillie, R. D., J. Lab. & Clin. 

 Methods, 1944, 24, 35-42). This gives 

 good account of all oil soluble dyes as 

 fat stains. 



Sudan G, see Sudan III. 



Sudan Hydrotropes. Sudan stains are rela- 

 tively insoluble in water. They can be 

 changed to hydrotropes (Neuberg) which 

 are water soluble. The hydrotropes of 

 red lipid stains are of a blue color 

 which changes to red when the dye 

 passes into a lipid or a lipid solvent. 

 This is the basis of a useful technique 

 for lipids (Hadjioloff, A., Bull. d'Hist. 

 Appl., 1938, 15, 37-41). 



Sudan R (CI, 113)— brilliant fat scarlet B, 

 oil Vermillion — A weakly acid mono-azo 

 dye. 



Sudan Red, see Magdala Red. 



Sulfhydryl Groups. 1. Prussian blue histo- 

 chemical reaction for (Ch^vremont, M. 



and Frederic, J. Arch, de Biol., 1943, 

 54, 589-605). Fresh or fixed tissue sec- 

 tions or smears can be used. Formol, 

 formol Ringer (saline) and Bouin are 

 suitable fixatives; but fluids containing 

 sublimate, such as those of Zenker and 

 Helly are contraindicated. The opti- 

 mum time of fixation is from a few hours 

 to one day. Time of heating during 

 paraffin embedding should be reduced 

 to a minimum. Wash sections care- 

 fully in aq. dest. to remove formalin. 

 Plunge sections or smears in 3 succes- 

 sive baths of the following mixture: 

 1 part fresh 0.1% aq. ferricyanide of 

 potassium (For Analysis, C.P.) and 3 

 parts 1% aq. ferric sulphate (For Anal- 

 ysis, C.P.). The mixture thus pre- 

 pared has a pH of 2.4 and, in ordinary 

 light, it is stable for 2 hrs.; in darkness 

 it lasts longer. The time in the baths 

 is approximately 10-20 min. for frozen 

 sections, 20-25 min. for paraffin sections 

 and for blood smears and 1 hr. for 

 smears of yeast. If desired, stain the 

 background with Azo carmin. No 

 metal instruments must enter the baths. 

 A positive result is indicated by appear- 

 ance in cells of blue granules or of a blue 

 colloidal precipitate which gives the im- 

 pression of being diffuse. After long 

 washing in water preparations can be 

 mounted in Canada balsam after dehy- 

 dration or in syrup of levulose without 

 dehydration. They last as long as 7 

 months. Consult original article for 

 histochemical controls and for illustra- 

 tions of epidermis and other tissues. 



2. Another reaction is given as fol- 

 lows by Serra, J. A., Stain Techn., 1946, 

 21, 5-18: "This reaction has been exten- 

 sively used for the study of the dis- 

 tribution of the tripetide glutathione. 

 One of the better methods of accom- 

 plishing the reaction is that of Giroud 

 and Bulliard (see Lison, 1936), which 

 gives a stable red coloration, while 

 other methods produce a violet color 

 rapidly fading away. 



"The pieces are immersed for some 

 seconds (in general an excess of time 

 does no harm) in a 5% aqueous solution 

 of zinc acetate. Directly afterwards 

 they are treated with a 10% aqueous 

 solution of sodium nitroprusside, con- 

 taining about 2% concentrated am- 

 monia. The pieces acquire a bright 

 red coloration, which attains its ma.xi- 

 mum in 3-5 minutes. Afterwards they 

 are mounted in pure glycerin for micro- 

 scopic observation, if necessary with a 

 preliminary washing in distilled water. 



"The materials may be studied 

 freshly or after fixation. It must be 

 noted, however, that the majority of 

 the fixatives hinder the reaction. We 



