NIPPLE SECRETION SMEARS 



230 



NISSL BODIES 



The reaction consists of immersing 

 the sections or fresh materials in equal 

 volumes of 0.4% aq. triketo-hydrinden- 

 hydrate (ninhydrin) and phosphate 

 buffer pH 6.98. The ninhydrin solution 

 must be freshly prepared and the phos- 

 phate buffer not too concentrated. For 

 the latter he suggests 6 cc. M/15 solu- 

 tion secondary sodium phosphate 

 (11.1876 gm. Na2HP04-2H20 per liter) 

 and 4 cc. M/15 primary potassium phos- 

 phate (9.078 gm. KH2PO4 per liter). 

 The reaction is carried outin a covered 

 glass container placed on a boiling 

 water bath. This is allowed to stand 

 1-2 min. in the vapor after it has 

 reached the boiling point. A blue, or 

 violet, color developing while hot or 

 after cooling indicates the presence of 

 amino acids, fre, or bound in peptides, 

 or proteins. 



For microscopic examination mount 

 in pure glycerin squeezing if necessary. 

 The edges can be cemented by using a 

 mixture of 80 gm. collophonium and 

 20 gms. heated lanolin as recommended 

 by Romeis but they must be studied the 

 same day for the color fades quickly. 



Serra carefully states that the reac- 

 tion is given, not only by all amino 

 acids except proline and hydroxypro- 

 line, by peptides and proteins but also 

 by other compounds such as amines, 

 aldehydes, sugars with free aldehyde or 

 keto groups and by ammonia and am- 

 monium salts. "However, with com- 

 pounds other than amino acids and 

 proteides, the reaction is much less 

 sensitive and sometimes it gives a more 

 reddish color. In general it is easy to 

 exclude the possibility of these com- 

 pounds being present, by their solubil- 

 ity and localization. It must also be 

 remembered that the intensity of the 

 ninhydrin reaction varies according to 

 the nature of the amino acid and the 

 binding of this in the peptides. 



"The coloring formed during the 

 reaction can diffuse and be absorbed 

 by several cell structures. This com- 

 monly happens when the heating is 

 exaggerated and when compounds easily 

 soluble are present, for instance after a 

 weak fixation. It is, therefore, recom- 

 mended to employ fixatives which 

 harden the tissues, as we have said 

 above. To be sure that a secondary im- 

 pregnation or adsorption of the coloring 

 has not taken place, the following test 

 may be executed : A small weight (some 

 milligrams) of a pure amino acid, such 

 as glycine, is dissolved in distilled 

 water; an equal volume of phosphate 

 buffer of pH 6.98 and a few drops of 0.4% 

 ninhydrin solution are added; it is 

 boiled slowly and cooled for 20-30 



minutes. The ninhydrin employed 

 must be completely consumed — by addi- 

 tion of more amino acid solution. The 

 colored liquid of this reaction is now 

 used to immerse the pieces, with boiling, 

 etc., as for a ninhydrin reaction. If 

 then a certain structure shows a colora- 

 tion, this means that an absorption or 

 adsorption has taken place and a posi- 

 tive ninhydrin reaction in the same 

 structure does not necessarily demon- 

 strate a proteic or amino acid nature." 



Nipple Secretion Smears, see Papanicolaou 

 Techniques. 



Nissl Bodies (Tigroid bodies, chromophile 

 granules, chromidia, etc.) are masses 

 of basophilic material easily demon- 

 strable in the cytoplasm of most nerve 

 cells after a wide variety of fixations. 

 Certain types of nerve cells are char- 

 acterized by the shape, number, size 

 and distribution of their Nissl bodies. 

 Since, moreover, the Nissl bodies ap- 

 pear at a definite stage in the develop- 

 ment of the cells and undergo distinctive 

 modifications in physiological and path- 

 ological conditions there can be no 

 question that they represent material 

 present in vivo although they cannot 

 be distinguished as such in living nerve 

 cells. Bensley, R. R. and Gersh, I., 

 Anat. Rec, 1933, 47, 217-237 claim that 

 their discovery of well-formed Nissl 

 bodies, stainable with toluidin blue, in 

 sections of tissues frozen in liquid air 

 and dehydrated in vacuo while still 

 frozen is proof of the presence of Nissl 

 bodies in the living state. Wiemann, 

 W., Zeit. f. d. ges. Neurol, u. Psychiat., 

 1925, 98, 347-404 appears to have made 

 ultraviolet photomicrographs of Nissl 

 bodies, and a dense ash, revealed by 

 microincineration (Scott, G. H., Proc. 

 Soc. Exp. Biol. & Med., 1940, 44, 397- 

 398), corresponds with them topo- 

 graphically. 



The influence of fixation on the shape 

 (and perhaps to a slight degree on the 

 distribution) of Nissl bodies in nerve 

 cells has never been clearly defined. 

 It is known that the Nissl bodies are 

 much more pronounced after fixation in 

 95% alcohol, Zenker's fluid and Car- 

 ney's fluid than they are after fixation 

 in osmic acid, Altmann's fluid and 

 Regaud's fluid. Fixatives of the first 

 group also result in more stainable 

 particles in the nucleoplasm than those 

 of the second. For other details see 

 Hopkins, A. E., Anat. Rec, 1924, 28, 

 157-163. Influence of staining is also 

 a factor to be reckoned with because 

 of the striking difference in appearance 

 of Nissl bodies when intensely and 

 lightly colored. There are many 

 methods from which to make a choice. 



