[Anoxic lesion of the working myocardial cell. Ultrastructural aspects]

A study was made of the effects of anoxia on the ultrastructure of the ordinary myocardial cell. Guineapigs were placed in a Plexiglass chamber, in which the flow of gases comprising the low oxygen mixture could be regulated. Blood samples were taken before, during and after acute and chronic anoxia experiments. Afterwards, five animals were kept alive for a further 10 days' follow-up, and six were used as controls. The material was perfused and fixed in accordance with various methods, and photographed through a Phillips M 300 electron microscope. Myocardial damage varied in area and incidence in function of the degree of anoxia, and appeared earlier, as well as at a higher oxygen content, in older animals, and in function of size. It may thus be supposed that such lesions appear earlier in man than in small animals. Due to containment of fuel costs, aircrew are more exposed than before to chronic hypoxia. The lesions indicated that chronic hypoxia leads to degeneration and regeneration, reflecting their relation to haemodynamic and biochemical mechanisms underlying the body's adaptation response.