RADI()-PR0TI:C:TIVK action of 5-HYDROX^ l RM'I amixk 



you used you saw any sucli piolcilion against cataract formation in the rats that 

 received 1000 to IGOO r and lived? 



Mr. van oen Brenk: Yes, I saw that there were very few rats whic li had developed 

 cataracts in the survivors. I should have mentioned that point. I suppose I have got 

 200 of these surviving rats now alive from six to twelve months and there are very 

 few that have cataracts — the odd one we do see. I might mention with regard to 

 the local effect of 5-hydroxytryptamine that Bacq reported that cysteamine (I think 

 he used cysteamine), given as an ointment and rubbed into the skin, gave substantial 

 protection. He used this as an argument for it acting by competitive radical formation 

 because there could be no vascular or anoxic effect. That, of course, is doubtful. 

 I have repeated the experiments with cysteamine, 5-hydroxytryptamine, adrenalin 

 and several other protective substances, using 10 per cent ointments rubbed into the 

 skin and I could never obtain anything like the radio-protective action that I showed 

 in skin when the animal received the substance parenterally before irradiation. 

 There is a slight reduction in skin damage, but it is only slight. 



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