PALLADIUM 



253 



PAPANICOLAOU TECHNIQUES 



9.2-8.2 but he made them up in a dif- 

 ferent way. 



Palladium. Histochemical detection based 

 on reaction between palladium and p- 

 Dimethylaminobenzyl-idenrhodanin in 

 neutral formalin or alcohol fixed tissues 

 (Okamoto, K., Mikami, G. and Nishida, 

 M., Acta Scholae Med. Univ. Imp. in 

 Kioto, 1939, 22, 382-387). 



Panchrome is a modification by Pappenheim 

 (Folia haematol., Arch., 1911, 11, 194) 

 of the Giemsa stain. Add 0.75 gm. of 

 the panchrome powder (Griibler) to 75 

 cc. pure methyl alcohol and 25 cc. acid 

 free glycerin at 60°C. After filtering 

 keep in glass stoppered bottle. Use 

 after May-Griinwald fixation as de- 

 scribed for Giemsa after methyl alcohol 

 fixation. According to Slider and 

 Downey (McClung's Microscopical 

 Technique, p. 329) it gives better 

 coloration of neutrophilic granules and 

 metachromasia of mast granules than 

 the plain Giemsa's stain but "some 

 delicacy is lost, and the cells are more 

 likely to be muddy." 



Pancreas. This organ lends itself very well 

 to microscopic examination in the fresh 

 state. The classic which everyone seek- 

 ing technical details should consult is 

 Bensley, R. R., Am. J. Anat., 1911, 12, 

 297-388. The techniques for Blood 

 Vessels and Nerve Endings are those 

 employed generally and are described 

 under these headings. No particular 

 difficulties will be encountered in their 

 adaptation to the pancreas. It may be 

 helpful however to consult Beck, J. S. 

 P. and Berg, B. N., Am. J. Path., 1931, 

 7, 31-35 on the blood vessels. The 

 same holds for the Connective Tissue 

 components. Epithelial parts of the 

 pancreas can routinely be examined in a 

 preliminary way with the other parts in 

 tissues fixed in Formalin-Zenker and 

 stained with Hematoxylin and Eosin. 

 For details see Zymogen, Ducts and 

 Islets of Langerhans. 



Pancreatin digestion method for spleen 

 (Kyes, P., Am. J. Anat., 1901, 1, 37- 

 43). 



Paneth Cells. Influence of fasting on 

 (Klein, S., Am. J. Anat., 1905-1906, 5, 

 315-330). To observe storage and dis- 

 charge phases examine in guinea pigs 24 

 and 6 hrs. after feeding (Klein, S., Am. 

 J. Anat., 1905-06, 5, 315-330) . By com- 

 bining DeGalantha's amyloid stain with 

 mucicarmine, Paneth granules are col- 

 ored green and mucous granules red 

 (Hertzog, A. J., Am. J. Path., 1937, 

 13, 351-360). 



Pantothenic Acid. Detection by fluores- 

 cence microscopy in tomato plants 

 (Bonner, J. and Dorland, R., Am. J. 

 Bot., 1943, 30, 414-418). 



Papanicolaou Techniques in Exfoliative 



Cytology— written by Charlotte M. 

 Street, Department of Anatomy, Cor- 

 nell University Medical College, New 

 York. May 21, 1951— Exfoliative cy- 

 tology, i.e. the study of cells which 

 have been exfoliated from the epithelial 

 lining of an organ or cavity of the body, 

 is gradually becoming an independent 

 branch of the morphological sciences. 

 Its usefulness in hormonal studies and 

 in cancer diagnosis has been largely 

 responsible for its great expansion in 

 the last two decades. The progress 

 achieved in this field has been primarily 

 due to the introduction of more ade- 

 quate technical methods for the preser- 

 vation and staining of cells in smears 

 prepared from various physiological 

 secretions. The techniques described 

 herein will be limited chiefly to those 

 which have been developed by Dr. 

 George N. Papanicolaou in the course 

 of his cytologic studies, and which are 

 now in use in his laboratory in the De- 

 partment of Anatomy of Cornell Uni- 

 versity Medical College. 



These technical procedures are based 

 on the use of smears which are fixed 

 without drying, in a solution of equal 

 parts of 95'% ethyl alcohol and ether, 

 by which good preservation of e.xfoli- 

 ated cells is attained. In such fixed 

 smears the cells are well preserved and 

 when stained, their cytoplasmic and 

 nuclear details are clearly defined. On 

 the contrary, in dried, unfixed smears 

 many of the structural details are lost, 

 there is an apparent increase in the 

 size of the cells and their nuclei, and 

 their affinity for stains is much im- 

 paired. Since cells subjected to drying 

 prior to fixation show a preference for 

 acidophilic stains, it is impossible in 

 dried smears to make the proper evalua- 

 tion of basophilic and acidophilic cells 

 which is so necessary in endocrine 

 studies. Furthermore, in the examina- 

 tion of smears for malignant cells, 

 good nuclear preservation and staining 

 are of utmost importance. For this 

 reason thorough fixation of wet smears 

 is essential. The relative size of cells 

 and the nuclear-cytoplasmic ratio also 

 play an important role in the diagnosis 

 of malignancy. Therefore, drj^ing of 

 smears which results in apparent en- 

 largement of cells and nuclei may give 

 a false impression of malignancy. 



The development of Papanicolaou's 

 staining procedures may be divided into 

 two periods. The first includes his 

 animal experimentation and his early 

 work in the human, during which vagi- 

 nal smears were used as an index for 

 evaluating cytologic changes occurring 



