I 



SOME CONTRIBUTIONS 



OF FLUORESCENCE MICROSCOPY 



TO THE HISTOCHEMISTRY OF THE SKIN 



A. JARRETT 



Reader in Dermatological Histology, U.C. H. Médical School, 

 Dermatology Dept. University Collège Hospital Médical School, London 



Thioflavine T 



Because it combines with nuclear proteins thioflavine T can be employed 

 for their localisation in tissues. On excitation with filtered ultra-violet 

 irradiation the nuclear proteins fluoresce a bri^t yellow. After incubating 

 histological sections with either ribonuclease or desoxyribonuclease the 

 remaining nucleic acid can be accurately located. Attempts hâve been 

 made to measure the intensity of the induced yellow fluorescence by 

 photometry and other methods. By estimating the li^t intensity before 

 and after enzyme digestion a value for the RNA/DNA ratio can be cal- 

 culated. Dur investigations with this histochemical method for the détermi- 

 nation of the RNA/DNA ratio are briefly described. 

 Congo red thioflavine T 



The value of congo red and thioflavine T for the differentiation of 

 skin keratins by differential colour fluorescence will be described to- 

 gether with illustrations of some experimaital changes induced by vitamin 

 A and triamcinolone on epidermal keratin. 

 Titan yellow 



In addition the use of fluorescence microscopy and the fluorochrome 

 titan yellow for the détection of magnésium in animal epidermis will 

 be reported. 



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