made prior to irradiation exposure at 20gy to 50gy hair loss in the treated tempo subjects is less severe and returns to normal more rapidly than in the control group similarly treated with the same ethanol water solution without tempo skin samples obtained from the treated group test positive for the presence of 4 hydroxy tempo while other tissue and blood specimens generally test negative the application of the solution can also continue daily after the irradiation exposure see goffman et al 34 topical application of nitroxide protects radiation induced alopecia in guinea pigs 34 international journal of radiation oncology biology and physics volume 22 pp 803 806 1992 which is hereby incorporated herein by reference a 0 4 or 1 mm solution of tempo is used to significantly reduce cardiac injury caused by reperfusion arrhythmia ventricular fibrillation and ventricular tachycardia as well as post ischemic release of lactate dehydrogenase and oh formation in isolated rat heads subjected to regional ischemia the rat heads are obtained and perfused using a modified krebs henseleit kh buffer as detailed in gelvan et al 34 cardiac reperfusion damage prevented by a nitroxide free radical 34 proceedings of the national academy of sciences usa medical sciences vol 88 pp 4680 4684 june 1991 which is hereby incorporated herein by reference in which the tempo solution was added to the perfusate after reperfusion head function and resulting damage is analyzed tempo is found to strongly protect against reperfusion injury by preventing oh formation rather than by decreasing heart rate or by direct suppression of arrhythmia the invention is described above and illustrated herein with reference to specific chemical formulas preparations and therapeutic.