Chapter 16 



THE ULTRAMOLET ABSORPTION SPECTRA OF PLASMA AND 



HEMOGLOBIN SOLUTIONS FROIM THE BLOOD OF 



NEUTRON-IRRADIATED RABBITS AND DOGS 



By EDWARD B. SAXIGAR 



There is much published work sho^^^ng that the irradiation of an animal 

 by neutrons causes a profoimd involvement of body organs ^\•ith consider- 

 able dismption of normal bodily functions (e.g., 1). Some of these dis- 

 turbances are reflected bj' abnormalities in the blood and blood plasma of 

 the animal. For example, the plasmas of animals subjected to neutron 

 irradiation of sufficient intensity and magnitude show de\4ations from the 

 normal in their elect rophoretic patterns (2, 3, 4) even though neutron 

 irradiation of noi'mal rabbit plasma in vitro is without effect (3). 



Although blood plasma contains a number of fractions whose character- 

 istic properties enable them to be distinguished by chemical or by electro- 

 phoretic means, it shows only one peak on the ultraviolet absorption cun^e. 

 The position of the maximum point of this peak, approximately 2800 A, 

 as well as the shape of the absorption curve, is the same for serum and 

 plasma from different animal species (e.g., 5). 



Since the ultraviolet absorption of plasma has been established as due 

 to the amino acid constituents of plasma, particularly the aromatic amino 

 acids tryptophane, tyrosine, and phenylalanine (6), the degradation of 

 plasma proteins even to the corresponding amino acids would not be ex- 

 pected to alter appreciably the shape of the absorption curve or the position 

 of its maximum. No such profound degradation of plasma proteins is, 

 however, indicated by the electrophoresis cuiwes for the plasmas from 

 neutron-irradiated animals. 



Further, irradiation of serum albumin in solution ^^'ith 29,000 Roentgen 

 units of soft X-rays (Cu target, 100,000 volts) has been sho%Mi to be ^^'ithout 

 effect on its ultraviolet absorption spectrum (7). While the effects of 

 neutron irradiation on the animal body are much more pronoimced than 

 those of X-rays, the two forms of radiation are similar, producing similar 

 bodilj' disorders and radiation sickness (la). 



It is thus possible to establish by argument the improbability of the 

 neutron irradiation of an animal causing any change in the ultraviolet 

 curve of its plasma or serum. Nevertheless it was thought desirable to 

 test the validity of this conclusion b\' the determination of the ultraviolet 



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