NUCLEOLUS 



178 



OLIGODENDROGLIA 



look something like plasmosomes . For 

 example, the nuclear inclusions in Borna 

 disease are acidophilic and may be of 

 the same size as plasmosomes ; but, they 

 like others of type B are strongly 

 acidophilic, are seldom tinged with 

 basic stains and are generallj'^ surrounded 

 by halos of unstained nucleoplasm. 

 Moreover they are not present in normal 

 animals. 



Secondly cells are sometimes encoun- 

 tered in which there is an increase in 

 acidophilic nuclear material often ac- 

 companied by nuclear hypertrophy. 

 The material may occur in the form 

 of dense spherules or of masses which 

 are bluntly angular and without halos. 

 Colored illustrations of liver cell nuclei 

 are given by Cowdry, E. V. and Kitchen, 

 S. F., Am. J. Hyg., 1930, 11, 227-299, 

 figs. 43 and 44. These bodies may be 

 true nucleoli which have undergone 

 hypertrophy or they may be simply 

 accumulations in the nuclei of aci- 

 dophilic material. The only sure way 

 to tell would be to ascertain whether 

 they comport themselves like true 

 plasmosomes during mitosis but the 

 cells involved have not been seen in 

 division. In other conditions (glioma- 

 tous tumors, etc.) cells are found whose 

 nuclei are enlarged and possess roughly 

 spherical, vacuole-like masses of granu- 

 lar acidophilic material. The granules 

 have the appearance of coagula produced 

 by the fixative in a rather thin fluid 

 medium. There is no halo. Such 

 bodies are probablj'' not altered plas- 

 mosomes. Their density is much less. 

 Differential staining. Nucleoli are 

 colored brown after fixation in equal 

 parts of 1% aq. chromic acid and 10% 

 formalin and staining of chromosomes 

 by Feulgen Reaction (Bhaduri, P. N., 

 J. Roy. Micr. Sci., 1938, 58, 120-124). 



Nucleonucleolar Ratio recommended as an 

 aid in the grading of malignancy with 

 review of the literature (Mendes Fer- 

 reira, H. E., J. Lab. & Clin. Med., 1940- 

 41, 26, 1612-1628). 



Nucleotides, see Pentose Nucleotides. 



Nutriles, growth promoting (Williams, R. 

 J., Biol. Rev., 1941, 16, 49-80). 



Oi! Ehie NA (Calco) a stain which colors 

 rubber bright blue in various plant 

 species (Whittenberger, R. T., Stain 

 Techn., 1944, 19, 93-102). This dye is 

 also a good stain for fat in animal cells 

 (Lillie, R. D., Stain Techn., 1945, 20, 

 7-9). 



Oil Red IV, see Sudan IV. 



Oil Red AS, O, B or 3B, see Sudan IIL 



Oil Red O (CI, 73).— fast oil orange II, fat 

 ponceau, oil scarlet, orange RR, red B, 

 Sudan II — an acid mono-azo dye sug- 

 gested as fat stain by French, R. W., 

 Stain Techn., 1926, 1, 79. Proescher's 



(F., Stain Techn., 1927, 2, 60-61) oil red 

 pyridine stain for fat is to immerse 

 frozen sections of formalin, Muller- 

 formalin (see MuUer's fluid) and 5 cc. 

 10% formalin in 100 cc. sat. aq. picric 

 acid fixed tissues in 50% aq. pyridine, 

 3-5 min. Stain 3-5 min in 3-5 gms. oil 

 red O dissolved in 100 cc. 70% aq. 

 pyridine C.P. Differentiate in 50% 

 pyridine several minutes and counter- 

 stain for 2-3 min. in Delafield's Hema- 

 toxylin. Mount in levulose syrup. For 

 central nervous system differentiate 

 30 min. in pyridine and use 16 cc. Dela- 

 field's -|- 2 cc. glacial acetic acid. Ac- 

 cording to Proescher, oil red O stains 

 fats and lipids more intensely and 

 quickly than Sudan III or IV. 



Oil Scarlet, see Oil Red O. 



Oil Soluble Dyes. List with physical prop- 

 erties of each and use as fat stains. 

 Very comprehensive (Lillie, R. D., J. 

 Tech. Methods, 1944, 24, 37-45). 



Oil Vermillion, see Sudan R. 



Okajima's "omnichrom" stain (Ito, T., 

 Folia Anat. Jap., 1937, 15, 357-359). 



O'Leary's Brazilin Method. (Revised by 

 James L. O'Leary, Dept. of Anatomy, 

 Washington University, St. Louis, May 

 24, 1946.) For myelin sheaths. Run 

 paraffin, or celloidin sections of prop- 

 erly fixed and mordanted (Muller's 

 Fluid) tissue to water. After rinsing 

 transfer to 3% aq. potassium bichro- 

 mate or in Muller's fluid, 12-24 hrs. for 

 4-24 hrs. Stain in: 10% Grubler's 

 Brazilin in abs. ale. (1-6 months old), 

 10 cc; aq. dest., 100 cc; acetic acid, 

 glacial, 5 drops. Wash in aq. dest. 

 Differentiate in 0.25% aq. potassium 

 permanganate 1—5 min. Remove po- 

 tassium permanganate with Weil's solu- 

 tion (oxalic acid, 2.5 gm.; sodium 

 bisulphite, 2.5 gm.; aq. dest. 1,000 cc) 

 Sections should show gray matter light 

 pink, white matter brilliant red. Cell 

 bodies stain in addition to myelinated 

 fibers. If differentiation not complete 

 after first immersion in potassium per- 

 manganate followed by oxalic acid- 

 bisulphite mixture, repeat the proce- 

 dure.' Wash, dehydrate and mount. 



Oligodendroglia. Method for impregna- 

 tion with silver in pyroxylin (celloidin) 

 sections (Weil, H. and Davenport, H. 

 A., Trans. Chicago Path. Soc, 1933, 14, 

 95-96) . This resembles their Microglia 

 method. Wash sections in aq. dest. 

 and transfer to aq. dest. containing 1 

 drop cone, ammonia per 10 cc. Treat 

 for 15-20 sec. with silver solution made 

 up as for microglia except that 15% 

 aq. silver nitrate is used and the end 

 point of the titration is reached when 

 about 12 cc. of it have been added to the 

 2 cc. cone ammonia. Transfer to 10% 

 formalin and allow section to drop to 



