LEATHER BROWN 



174 



LEISHMANIA. MEDIA 



hematoxylin dissolved in few drops abs. 

 or 95% alcohol + 10 cc. freshly filtered 

 2% aq. K2HPO4 for 2-3 hrs. Wash 

 changing tap water 10-60 min., dehy- 

 drate in 95% ale, clear in terpineol and 

 mount in terpineol balsam. Lead light 

 to grayish blue, nuclei deep blue. 

 Another method applicable to paraffin 

 sections of Zenker fixed material is to 

 stain in 0.1% methylene blue in 20% 

 ale. 10-20 min. Differentiate 10-20 

 min. in 95% ale, dehydrate, clear and 

 mount. Phloxine is recommended as a 

 contrast stain before the methylene 

 blue. 



2. Chromate method (Frankenberger, 

 Cretin). By simply fixing in Regaud's 

 Fluid lead is precipitated as insoluble 

 yellow lead chromate easily identifiable 

 microscopically. This method is 

 strongly advised by Lison (p. 101). 

 It has been used by True (E., Bull. 

 d'Hist. Appl., 1929, 6, 393-399). See 

 Sieber (E., Arch. f. exper. path. u. 

 pharmak., 1936, 181, 273-280) for demon- 

 stration of lead in bones. 



3. Attempts have been made to 

 identify lead after microincineration by 

 exposure to hydrogen sulphide, because 

 lead sulphide is black, but Gordon H. 

 Scott emphasizes difficulty in dis- 

 tinguishing it from other sulphides and 

 from carbon in imperfectly incinerated 

 specimens (McClung, p. 660). 



4. The method of Sieber, E., Arch. f. 

 exper. Path. u. Pharmak., 1939, 181, 

 273 depending on production of acid 

 resistant brown-black lead sulfide when 

 tissue is treated with acidulated H2S 

 solution is said to be satisfactory by 

 Gomori, G., J. Mt. Sinai Hosp., 1944- 

 45, 11, 317-326 when presence of other 

 heavy metals is ruled out. 



Methods for chemical determination 

 of lead in biological materials are 

 important as checks on above. Consult 

 Smith, F. L. 2nd., Rathmell, T. K. and 

 Williams, T. L., Am. J. Clin. Path., 

 1941, 11, Suppl. 5, 653-668. 



For a convenient method of giving 

 colloidal lead intravenously to rabbits 

 see Crawford, B. L., Stewart, H.L., 

 Willoughby, C. E. and Smith, F. L., 

 Am. J. Cancer, 1938, 33, 401^22. The 

 authors describe techniques for direct 

 analysis of lead in the tissues. 



Leather Brown, see Bismark Brown Y. 



Leather Yellow, see Phosphine. 



Leblond, see Radioantographic Technique. 



Lebowich's soap-wax technique eliminates 

 use of alcohol , xylol and overnight drying 

 of paraffin sections. Takes only 6-8 hrs. 

 (Moritz, C. E., Stain Techn., 1939, 14, 

 17-20). 



L. E. Cells. The discovery of these cells 

 in acute disseminated lupus erythe- 



matosus by Hargraves, M. M., Rich- 

 mond, M. and Morton, R., Proc. Staff 

 Meet., Mayo Clin., 1948, 23, 25-28, was 

 a definite advance in diagnostic pro- 

 cedure. The simplest test for L. E. 

 cells is that of Lee, Stanley L., Am. J. 

 Clin. Path., 1951, 21, 492-496. With- 

 draw 1-2 cc. venous blood into a clear 

 dry test tube. Let clot and remain at 

 room temperature for 2 hrs.; with 

 wooden applicator "fish out" the clot. 



Lecithin, a compound of phosphoric acid, 

 glycerol, choline and 2 fatty acid mole- 

 cules. It is a phosphatide soluble in 

 alcohol, chloroform, ether and benzene, 

 see Lipoids. 



Lee-Brown. Modification of Mallory's ani- 

 line blue connective tissue stain (Lee- 

 Brown, R. K., and Laidley, J. W. S., 

 J. Urol., 1929, 21, 259-274). Mallory 

 (p. 155) states that the following tech- 

 nique is particularly valuable for the 

 kidney. Treat paraffin sections of Zen- 

 ker fixed material with iodine to remove 

 mercury. Wash. 1% aq. phosphomolyb- 

 dic acid, 30 sec. Wash in aq. dest. 1-2 

 min. Stain in: aniline blue, 0.5 gm.; 

 orange G., 2 gm. ; phosphomolybdic acid, 

 2 gm.; aq. dest., 100 cc. for 30 min. at 

 55 °C. Wash in an. dest 2-5 min. 1% 

 aq. phosphomolybdic acid, 30 sec. 95% 

 ale . , abs . ale . , xylol , balsam . Glomerular 

 basement membrane and collagen, deep 

 blue; nuclei, orange. 



Leishmania Donovani, a search for stains 

 that will color more rapidly than Giemsa 

 revealed Astra violet F. F. Extra, 

 Himmelblau, Magenta Lermont and 

 Navy blue shade, each to be used in 

 fresh 10% aq. solution (Takasaki, S., 

 Lues, Tokyo, 1938, 16, 127). 



Leishmania. Media. Direct microscopic 

 examination of peripheral blood may 

 be negative while detection in culture 

 is feasible. Q. M. Geiman (Simmons 

 and Gentzkow) recommends addition 

 of 10 cc. blood to sodium citrate in 

 physiological saline, centrifuge and in- 

 oculate few drops buffey coat into tubes 

 of NNN medium, incubate 22-28°C. and 

 examine microscopically 10-20th day 

 for motile forms. The following media 

 are abbreviated from Geiman 's ac- 

 count. 



1. Blood agar or NNN (Novy, Mac- 

 Neal and Nicolle, 1908). Agar, 14 gm., 

 sodium chloride, 6 gm., aq. dest. 1000 

 cc. Add 5 vol. sterile defibrinated 

 rabbit's blood cooled to 45°-50°C. Mix, 

 tube long slant. After agar sets, cap 

 with sterile rubber stoppers. Prove 

 sterility by incubation 37°C., 24 hrs. 

 Inoculate material to be cultivated on 

 slant and in water of condensation. 

 Incubate 20°-25°C. Transfer every 20- 

 30 days to maintain. 



