SULFHYDRYL GROUPS 



329 



SULFONPHTHALEINS 



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 awaJ^ 



"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 maxi- 

 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 

 obtained good results with a fixation in 

 10% neutral formaldehyde during 2-15 

 hours at room temperature. A more 

 prolonged action of this fixative also 

 hinders the reaction; it is recommended, 

 therefore, that if possible 2-4 hours of 

 fixation be used. 



"The results of the reaction have 

 different meanings according to the 

 fixation, washings, etc., because the 

 glutathione is partly soluble. When 

 the tissues are treated several times 

 with a 10% solution of trichloroacetic 

 acid for 15 minutes, the glutathione is 

 dissolved and only "fixed", that is, pro- 

 teic sulfhydryl groups remain in the 

 preparation. It is still possible not 

 only to demonstrate the existing SH 

 groups but also to reduce SS groups to 

 SH groups, by means of a pre-treatment 

 of the materials with a solution of 10% 

 KCN for 10 minutes in a small stoppered 

 bottle (the cyanide solution can be 



weakly alkalinized with potassium hy- 

 droxide, to make its use safe). 



"The reaction has been recognized aa 

 well localized, but in case of doubt a 

 test of secondary impregnation can be 

 made in the way described for the 

 ninhydrin." See Nitroprusside Reac- 

 tion. 

 Sulfmethemoglobin, a greenish compound 

 of methemoglobin and sulphur often 

 encountered in abdominal walls of 

 cadavers, but it may be present in 

 blood where it can be diagnosed by 

 spectroscopic examination (Mallory, 

 p. 135). 

 Sulfonamides. Great importance of sulfa 

 drugs makes their demonstration in 

 tissues useful. Mackee, G. M., Herr- 

 mann, F., Baer, R. L. and Sulzberger, 

 M. B., Science, 1943, 98, 66-68; J. Lab. 

 & Clin. Med., 1943, 28, 1642-1649. 



Fix fresh tissue with dry formalde- 

 hyde gas and visualize sulfa compounds 

 as orange precipitates in frozen sections 

 treated with p-dimethylaminobenzalde- 

 hyde in acid alcohol solution. In at- 

 tempting to identify sulfonamides 

 microscopically in urinary sediments 

 the descriptions and diagrams of the 

 various crystals given by C. J. Gentz- 

 kow and H. A. Van Auken in Simmons 

 and Gentzkow will be helpful, viz. 



Sulfadiazine: (1) free drug, "dark 

 greenish irregularity striated spheres 

 with either fuzzy or clean edges"; (2) 

 acetyl crystals like "sheaves of wheat 

 with eccentric bindings". 



Sulfaguanidine : (1) free drug, rare; 

 (2) acetyl crystals as "thin oblong 

 plates, clear or with fine mesh pattern, 

 often aggregated into cross or star-like 

 clusters". 



Sulfanilamide: (1) free drug as large 

 needles with angle of 106° at ends 

 often in sheaves; (2) acetyl crystals 

 similar needles with square ends. 



Sulfapyridine : (1) free drug as stubby 

 prisms; (2) acetyl crystals as "boat- 

 or petal -shaped forms with rounded 

 edges; start angled crystals; bow ties or 

 burrs; and occasionally as large ro- 

 settes." 



Sulphathiazole: (1) free drug rare as 

 flattened or 6 sided crystals with angle 

 at end of 84°; (2) acetyl crystals may 

 resemble those of free drug but with 

 end angles of 136° when they look like 

 wheat sheaves with central binding. 

 These may be swollen suggesting 2 half 

 circles fused at center; striated spheru- 

 lites frequently occur. 



Sulfasuccidine crystals absent be- 

 cause of but slight absorption of this 

 drug from intestine. 

 Sulfonphthaleins. These are compounds of 

 phthalic anhydride and ortho-sulfo- 



