Hans Georg Gesser (1942-2023)
We are very sad to announce that Hans Gesser died on Saturday evening (17th June 2023) at home, a few weeks after his 81st birthday. He was surrounded by his family.
Hans Gesser received his PhD (then called Fil. Dr.) in 1974 at the Zoophysiology Department in Gothenburg (Sweden) under supervision of Professor Ragnar Fange (1920-1999). During his doctoral studies, Hans also teamed up with Professor Otakar Poupa (1916-1999), who had to flee the “Prague School” of Developmental and Comparative Cardiology in 1968, and spent the rest of his life in exile in Scandinavia. Poupa was a good friend of Professor Kjell Johansen, the founder our section for Zoophysiology in Aarhus in 1972, and their relationship likely played a role when Hans was offered a position as Associate Professor in Aarhus in 1975. Hans was promoted to Docent in 1989.
Hans’ earliest studies pertained to aerobic and anaerobic metabolism in the swim bladder of fish, but – likely under the influence of Poupa – he subsequently turned his interest to the metabolism and contractile properties of the cardiac muscle in fish. He was one of the first researchers to appreciate and study the metabolic and functional differences between the inner spongy part of the heart and the outer compact layer. While Hans’ research expanded and widened through his career, the fish heart muscle remained a central theme, and Hans became a leading expert in the world on this topic. He authored a several influential reviews that will continue to inspire this field of research.
Many of Hans’ approximately 100 publications were based on studies on heart strips, a technique where cardiac muscle strips are skilfully mounted in vitro to measure the force of contraction under controlled conditions. Using this preparation, Hans described the influence of acidosis, oxygen-lack, and high potassium on cardiac function and interpreted the responses in the context of cellular energy status and changes in membrane potential. He also made fundamental discoveries on the manner in which calcium levels are regulated and how this divalent ion affects the contraction of the heart. Much of his work was inspired by classic biomedical muscle physiology, and many of Hans’ papers will stand the test of time. Several of his former PhD students carry on pursuing these questions, continuing the Gesser-legacy.
Hans never led a large research group, but seemingly preferred to focus on a few students at a time who received close and extremely dedicated supervision in the planning and execution of the experiments and interpretation of the results. He collaborated abroad as a visiting scientist at Mount Desert Island Marine station, Mount Allison University, Plymouth, University of Bergen, and Federal University of Sao Carlos, Brazil. In Brazil, Hans studied calcium handling in the octopus heart and rumours tell that he was partial to a ‘Batida de Coco’ cocktail. Several groups in Brazil have implemented the use of isolated heart strips as a result of collaborating with Hans.
Hans was a devoted and engaging teacher, but his mixture of Danish and Swedish - that ended up being neither - probably hampered the transfer of knowledge during lectures to the undergraduates. It is not surprising therefore that his characteristic accent, not even surpassed in the Muppet show, inspired many jokes amongst his friends; his pronunciation of “Jim and Jordi” shall be fondly remembered by all of us.
When Hans retired in 2011, we arranged a one-day symposium with guests from all over the world, and many of his former students. Hans continued his experimental studies for several years and remained actively engaged in many collaborative projects, both in Aarhus as well as internationally until a few years ago. In Aarhus, we were very grateful that he continued as an active emeritus, as he remained a much-treasured colleague due to his razor-sharp thinking and generosity with ideas and insights. He was always kind in the meeting of others, and we shall miss his smile and crisply formulated, but always constructive and encouraging suggestions.
