OxyFile #94

TI:  Regional Oxygenation and Radiotherapy: A Study of the 
     Degradation of Infused Hydrogen Peroxide
     II. Measurement of Decomposition of H2O2 Infused Into 
         Flowing Blood

DT:  December 7, 1970

AU:  James I. MacNaughton

SO:  Int. J. Radiat. Bilog., 1971, Vol. 19, No. 5, pp 415-426

AB:  The degree of decomposition of hydrogen peroxide infused 
     into blood blowing in a model system has been measured under 
     various conditions.  The results show:

     1.  that infused peroxide probably tends to stream, and not 
         mix.  There is no evidence of marked turbulence at the 
         infusion point which would assist mixing.
     2.  decomposition is slower than previously believed.
     3.  in the clinical situation, hydrodynamic factors make 
         precise determination of the pO2 impossible.
     4.  the probability that free peroxide perfuses tumour 
         tissue is high.
     5.  in intra-arterial peroxide infusion, only plasma 
         catalase in involved, in the relevant time, in the 
         decomposition process.
     6.  a half time for catalase-peroxide reaction of 
         approximately 0-35 sec under the conditions of these 
         experiments.

     A "peroxide effect", comparable to but more potent than the 
     "oxygen effect", is postulated, and experimental studies or 
     earlier workers are reviewed in the light of this postulate.