Exfoliative Cytology 359 



Johnson and Klein {19'^6) apply the method to paraffin sections. 



Carson (1959) substitutes Technicon dehydrant- for ethyl alcohol, 

 thereby eliminating the need for reventie-taxed ethyl alcohol which 

 is diffictilt for some laboratories to obtain. 



MacLean {I960) describes processing Papanicolaou smears on the 

 Technicon. 



Fluorescent Method 



Provided the proper equipment is available, the fluorescent proce- 

 dure requires less time for preparation and less skill on the part of the 

 examiner than the Papanicolaou method. The polychrome staining is 

 so brilliant that cells are seen in sharp contrast against a black back- 

 groiuid, rendering mass screening simple and quick. Under low power 

 atypical cells show increased amotnits of fluorescence and suspicious 

 malignant cells are a brilliant flaming reddish orange (they seem to 

 glow) in contrast to normal cells, ^vhich may be greenish grey Avith 

 whitish yelloAV nticlei. The method is based on the differentiation of 

 RNA and DNA by acridine orange NO (AO). The RNA in the cyto- 

 plasm and the nucleoltis fluoresces red, while the DNA of the nucleus 

 fluoresces green. 



von Bertalanffy and Bickis (1956); von Bertalanffy, 

 Masin and Masin (1958) 



solutions: 



Acridine orange (AO): 

 Stock soliuion: 



acridine orange, C.I. 46005 0.1 gm. 



distilled water 100.0 ml. 



Keep in dark bottle in refrigerator. 



M/I5 phosphate buffer, pH 6: 



M/15 sodium phosphate, dibasic, Na2H2P04 



(11.876 gm./lOOO ml. water) 7.0 ml. 



M/15 potassium phosphate, KH.PO4 (9.078 



gm./lOOO ml. water) 43.0 ml. 



Keep in refrigerator. 



Working soliuion: 



AO stock solution 5.0 ml. 



buffer solution 45.0 ml. 



-Technicon Chemical Co., Chauncev, N.V. 



