NON-NEOPLASTIC LATE EFFECTS 



E. BRINKMAN 



Radiopathologisch Laboratorium der Rijksuniversiteit, Groningen, Holland 



SUMMARY 



A short comparison of ageing and late radiation effects leads to considerations on 

 "molecular", "cellular" and "nuclear" life-spans. The "vieillissement moleculaire" of 

 haemoglobins is mentioned. 



Most attention is paid to ageing and radiation changes of mucopolysaccharide tissue 

 matrix with embedded fibres. This converges on the hypothesis of basal membranes being 

 an important structure from which ageing by irradiation might be understood. Examples 

 are aortic intimal and glomerular basal membranes. 



The programme of this symposium now requires us to discuss non-neoplastic 

 late somatic effects, arising from early radiation exposure. From those I will 

 have to select the effects which may lead to damages shortening life-span. So 

 (/ changes in vital organs (arteries, nervous centres, kidneys) or severe break- 

 down of homeostasis will prevail over late effects in skin, in sensory organs, or 

 in the efficiency of co-ordinated mobility. 



Current opinion often considers late somatic effects as not much different 

 from "normal" ageing syndromes, the main effect of radiation being an 

 advancement of all causes of death, but at different rates (Lindop and Rotblat, 

 1961). Curtis (1961) defines "radiation-induced ageing" as a true" shortening 

 of the natural ageing process". 



To my knowledge, gerontology up to the present does not give much help 

 in analysmg causes of ageing, apart from considering them partially as non- 

 inevitable. But wherever some possible symptoms of ageing have been 

 ascertained, their similarity to late irradiation effects is great and one is 

 inclined to look for common general causes. It is said, that animals which 

 normally die predominantly of a particular disease such as nephrosclerosis, 

 will also die predominantly of the same disease following irradiation (Curtis, 

 1961). 



Starting from the "dynamic existence" of most biological structures with 

 turnovers, varying from a few hours to possibly years for the "life-span" of 

 their constituting macromolecules, it is conceivable, that this "molecular 

 life-span" might be influenced by age and by radiation. If the turnover of 

 mtracellular and extracellular macromolecules increases with cellular 

 metabolism, its retardation (for a certain period) by a hypocaloric diet appears 

 to increase life-span in rats and in pigs (McKay, 1952). If this points to a 



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