VISUALIZATION OF THE LYMPHATICS OF THE HEART AND THE MEDIASTINAL DRAINAGE PATHWAYS IN THE LIVING CYNOMOLGOUS (MACACA-MULATTA) MONKEY

Our interest in the effects of impaired cardiac lymph drainage on coro nary atherosclerosis led us to study the cardiac lymphatic anatomy in the monkey, generally considered the ideal experimental animal for exa mining coronary, artery disorders. Shortterm and long-term studies to visualize the cardiac lymphatic system and its mediastinal drainage pa thways in 14 living monkeys confirmed that the epicardial collecting l ymphatic anatomy is comparable to that of man, dog, and pig. These lym phatics, and particular lymphatic drainage to the cardiac lymph node i n the right mediastinum, are difficult to visualize, in good part, bec ause lymph uptake of such tracers as India Ink and T1824 blue dye is e xtremely slow. By modifying our techniques and faking cognizance of th e slow lymphatic uptake of the tracers, we have been more successful i n visualizing the mediastinal cardiac lymph node. Though our studies c onfirm that the lymphatic drainage of the monkey heart is similar to t hat in other mammals, we conclude that the ''monkey model'' has severa l drawbacks to study, the effects of impaired cardiac lymph flow becau se of the laborious requirements to visualize successfully the cardiac lymph node. Perhaps the development of new markers would make this ly mphatic system more approachable for experimental investigation.