The differential action of X-rays on tissue, growth and vitality.— Part II. The biological reaction to X-radiation in relation to a phenomenon termed antagonism
- 2 December 1930
- journal article
- research article
- Published by The Royal Society in Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character
- Vol. 107 (751) , 293-301
- https://doi.org/10.1098/rspb.1930.0072
Abstract
II. The allantoic membrane of the embryo chick, irradiated with homogeneous x-rays obtained by crystal diffraction, shows a reaction consisting of hypertrophy or atrophy which is associated with a definite frequency band. Any frequency outside this band tends to diminish or prevent the reaction. A prior dose of mixed radiation prevents a reaction due to homogeneous radiation. In this instance increasing doses of both radiations may be balanced against each other; a curve resembling a hyperbola was thus obtained. [long dash]III. The threshold dose for a reaction of the allantoic membrane to homogeneous x-radiation varies inversely as the square of the area irradiated for small areas. The reaction represents a summation of stimuli from adjacent parts which may not show any visible change. When 2 discrete areas are irradiated, a fused reaction may be obtained in the central non-irradiated part and the threshold dose varies as the square of the distance between parts up to 6.5 mm. Similar laws appear to hold when the skin of the rat is exposed to unfiltered soft mixed radiation and the possible role of the ionised atom is discussed.[long dash]IV. The allantoic membrane was exposed to homogeneous radiation for various periods of time at various intensities and the threshold dose was plotted against time. The curve showed a minimum value at li hrs. and 2 upward branches representing an increase in threshold dose when T is small and a "repair factor" when T is large. The skin of the mouse exposed to soft mixed radiation shows a similar curve except that repair was more rapid in the highly differentiated tissue. Approximate equation TD=K/T+ ([alpha]+[beta])T where [alpha] represents the return of the ionised atom to a normal state and [beta] a biological constant of repair.This publication has 0 references indexed in Scilit: