L. H. GRAY 



Table 1. The sensitivity of cells and tissues tn X radiation classified in relation 



to clepciidcnce on oxygen tension 



Biological 

 material 



Damage 



Reference 



A. Sensitivity positively correlated with oxygen tension 



Rat 



Mouse 



Guinea pig 



Chick 



Death from whole body exposure 



1 



2, 3, 4, 5 

 6 

 7 



Rat 

 Mouse 

 Guinea pig 



or 

 Rabbit 



>< 



Bone marrow 



Spleen 



Lymphocyte 



Skin 



Hair 



Bone 



Foetus in utero 



Chromosome structural damage 



Lens of eye 



Tumours 



8, 9 

 8 

 10 



11, 12, 13, 4, 5 



13 



14, 15 



16, 17 



9, 18 



19 



18, 20, 21, 22, 23, 



24, 25, 26 



Drosophila Chromosome structural damage (sperm irradiated) 27 



Recessive lethal mutation (sperm irradiated) 28 



Recessive lethal mutation (egg irradiated) 29 

 Reduced hatchability of egg due to: (a) nuclear, and 



{b) cytoplasmic injury 30, 31 



Suppression of ' Erupt Eye ' 32 



Formation of 'melanotic tumour' 33 



Grasshopper Mitotic inhibition in the neuroblast 34 



Sea urchin Cleavage delay in the egg 35 



Roots 



Microspores 

 Seeds 



Yeast 



Paramecium 

 Bacteria 



Phage 

 DNA 



Mitotic arrest 36 



Growth and survival 37 



Chromosome structural damage 38 



Chromosome structural damage 39, 40 

 Germination, subsequent growth and chromosome 



structural damage* 41, 42, 43 



Loss of colony forming ability 44 



Nine reverse mutations to growth factor independence 45 



Genetic damage leading to reduced viability 46 

 Loss of colony forming ability 47, 48, 49, 50 



Reverse mutation to purine independence in E. coli B/r 51 



Indirect inactivation including 'after-effect' 52, 53 



Loss of structural viscosity when 'after-effect' is • • 



included 54 



B. Correlation between sensitivity and oxygen tension either not evident or inverse 

 Dominant lethal mutations induced by irradiation of 



sperm| 

 Reverse mutation to streptomycin independence in 



r + 



Mouse 



Bacteria 



Paramecium 

 Phage 



Transforming 



principle 

 DNA 



Erythrocyte 



E. coli B/ri 

 Non-genetic damage 

 Direct inacti\ation 

 Indirect inactivation (immediate) 



Indirect inactivation (immediate) 

 Loss of structural viscosity (immediate effect, irra- 

 diated in dilute acjueous solution) 

 Leakage of potassium 



55 



51 

 46 

 56 



52,57 



58 



54 

 59 



• The sensitivity of barley seeds may not be influenced by gaseous atmosphere at the time of irradiation. An 

 influence of oxvgen is, however, clearly evident from studies of post-irradiation treatments. 



t This entry is based on the absence of an effect of hypoxia, which could be due to the fact that the sperm which 

 were tested are normally nearly anoxic. Dominant lethals due to irradiation of oocytes show an influence of hypoxia 

 and are therefore oxygen positive (60). Dominant lethals resulting from irradiation of Drosophila sperm show a small 

 effect of hypoxia (see text) (61). 



J A small positive dependence on oxygen was observed (see text). 



153 



