Discussion 101 



DISCUSSION 



Best: Prof. Tunbridge has already referred to some of the work of Dr. 

 Banga, and I would like to invite you, Prof. Balo, to give us a summary 

 of your findings ; perhaps a statement of what you think about the present 

 position of elastase. 



Bald: I reported on elastase in 1948, at the First Congress of Italian 

 Pathologists, at Forli. I had worked on this problem since 1938, and 

 at first I followed the work of Anitchkow. He found that after the admin- 

 istration of cholesterol one can bring about a special type of alteration 

 of the arteries, called "cholesterol atherosclerosis", where cholesterol 

 is deposited in the arteries ; but it is not always clearly distinguished from 

 other types of arteriosclerosis. In April 1956 I visited Prof. Anitchkow 

 in the Soviet Union and discussed this problem with him ; he believes that 

 this is the only type of arteriosclerosis and calls it "atherosclerosis". 

 I do not agree with this, but agree with Prof. Kallmann who has dis- 

 tinguished between this type of cholesterolsclerosis and the destruction 

 of elastic fibres which is, in fact, different from atherosclerosis. 



My work was carried out in collaboration with Dr. Banga and we have 

 published our findings (1949, Schweiz. Z. allg. Path., 12, 350; 1950, 

 Biochem. J., 46, 384). My first method was to put sections from the 

 carotid artery, which is rich in elastic fibres, into a solution of pancreatic 

 extract to give a watery extract ; later I took degreased specimens of the 

 pancreas and these again gave watery extracts, and I found when putting 

 the histological sections in the solution that the elastic fibres of the 

 arteries dissolved. 



Later on, biochemical methods were introduced and finally we carried 

 out the experiment in both ways. Because the test with the sections of 

 elastic arteries in elastase is very accurate, both methods can be used to 

 determine the elastolytic activity of a solution. 



We have considered that trypsin (which is a general proteolytic 

 enzyme in the pancreas) or chymotrypsin or some other enzymes might be 

 responsible for this solution of elastic fibres, but we found that crystal- 

 lized trypsin, which we received from Prof. Northrop, does not dissolve 

 the elastic fibres whereas elastase dissolves them readily. We purified 

 our specimens, and Dr. Banga obtained crystalline elastase. 



We were, of course, interested in the problem of how elastase worked 

 in the human organism. Early in our work we found that both human 

 and animal serum contain an inhibitor (to which Prof. Tunbridge has 

 referred) and that very small quantities of serum can inhibit the action 

 of elastase. As a result of these findings, we tried to define the possible 

 role of elastase in the organism. We removed the pancreas of the dog, 

 and on doing this we found some destruction of the elastic fibres. These 

 dogs were kept alive, some for more than one year and some for less than 

 one year, for 7, 10 or 12 months, which I believe is sufficient to demon- 

 strate the effect of the lack of elastase. In all these experiments we found 

 some alterations in the arteries after removal of the pancreas. In some 

 of these animals which I investigated I was at first led to believe that 

 remarkable alterations had occurred in the arteries; then I began to 



