SECTION I. HISTOCHIMIE PREPARATIVE 



II. APPLICATION TO LOCALIZATION OF ENZYMES 

 AND OTHER CHEMICALS 



JEFFREY P. CHANG and SAMUEL H. HORI 



Section of Expérimental Pathology, Department of Pathology, 

 The University of Texas M. D, Anderson Hospital and Tumor Institute, 



Houston, Texas, U.S.A. 



The application of the section freeze-substitution technique to the lo- 

 calization of enzymes and other substances in tissueâ is reported. The 

 following hâve been readily and precisely demonstrated in frozen-substi- 

 tuted tissues: oxidative enzymes, such as DPNH and TPNH diaphorases, 

 succinic dehydrogenase and choline dehydrogenase; hydrolytic enzymes, 

 such as alkaline and acid phosphatases, esterase, 5'-nucleotidase, amy- 

 lophosphorylase, and beta-glucuronidase; and chemical substances other 

 than enzymes, such as nucleic acids, carbohydrates, proteins and amino 

 acids, inorganic éléments, and soluble isotopes. The section freeze- 

 substitution technique appears to be a most versatile and reliable histo- 

 chemical procédure. Studies are currently being conducted to demonstrate 

 its fullest usefulness. 



- 3 - 



