[Pathomorphology and pathogenesis of radiation sickness in calves and young cattle following whole body roentgen irradiation].

Here are the most important pathomorphological findings recorded from 14 calves or heads of young cattle following whole-body X-ray treatment (170 R and u50 R median-line dosage): 1. Damage was caused to the haematopoietic system, with the most severe effects on granulopoiesis, thrombocytopoiesis, and lymphopoiesis, but less conspicuous lesion of erythropoiesis. 2. Haemorrhagic diathesis developed together with pneumonia in 86 per cent of all cases, manifested in most of them as severe fibrinous pneumonia and pleuropneumonia (in 75 per cent of the cases) and progressing pericarditis. 3. Liver degeneration occurred to all animals, usually in the form of centrobular liver cell necrobiosis (86 per cent), with most of the cases accompanied by diffuse degenerative hepatoparenchymal damage (80 per cent) as well as by granular degeneration of the myocardium and acute fubulonephrosis, the latter two processes obviously developing only short time before death. 4. Catarrhal as well as fibrinous and circumscribed diphtheroid enteritis developed in 43 per cent of all animals, those which had received a median-line dosage of 170 R. 5. Deficiency in supply was recorded, too, with severe damage to the haematopoietic organs being in the focus of the pathological process. That damage actually was the cause of the haematologically established granulocytopenia or agranulocytosis, thrombocytopenia, and lymphopenia. That was the background against which radiation syndrome of calf could be accompanied by activation of latent or subclinical infection of respiratory organs and the development of severe pneumonia as well as by changes in the intestinal flora leading to the outbreak of enteritis. The collapse of cellular defence mechanisms obviously caused intestinal induction of resorption of bacterial toxins and decomposed tissue products, with the pneumonia-damaged lungs being involved. The results eventually were intoxication with haemodynamic disorders, increase in vascular permeability, and degenerative damage to the parenchyma. Haemorrhagic diathesis was the result of thrombocytopenia and, possibly, endotoxic or toxic damage to the coagulation and blood vessel system. Further pathogenetic aspects relating to the radiation syndrome in calf and young cattle are discussed.