The study showed that all specimens with evidence of acute myocardial infarction (heart stoppage) showed intense immunoreactivity for HIF-1 alpha, which is a subunit of genes that carry hypoxia-inducible factors (HIF). HIF-1 is involved in the body's adaptive response to hypoxia (reduction in oxygen to body tissue, i.e., the heart in this case). HIF-1 alpha has been linked to the body's ability to expand blood vessels as a means of increasing oxygen to body tissue under conditions of hypoxia. The current study attempted to obtain quantitative and qualitative manifestations of antibody HIF-1 alpha in specimens of heart tissues affected by various degrees of damage, using an immunohistochemical method. The study also assessed the relationship between the manifestation of HIF-1 alpha and changes over time in human hearts deprived of oxygen. Although the authors advise that these findings should be interpreted with caution, they suggest that positive immunohistochemical revelation of HIF-1 alpha in heart samples is an indicator of heart malfunction due to hypoxia when there is no evidence of cardiac lesion under conventional microscopy. 2 tables, 6 figures, and 24 references