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Professor Karl Julius Ullrich—in memoriam

2010; Elsevier BV; Volume: 78; Issue: 9 Linguagem: Inglês

10.1038/ki.2010.368

1523-1755

Heini Murer, Gerhard Burckhardt,

Amino Acid Enzymes and Metabolism

Prof. Dr. med. Dr. h.c. mult. Karl Julius Ullrich, former head of the Department of Physiology at the Max Planck Institute of Biophysics in Frankfurt am Main, Germany, passed away on 2 August 2010, at the age of 84. In him we lose an outstanding renal physiologist. Born in Würzburg in 1925, he studied medicine there, earned his doctoral degree, and served as a resident at the Department of Internal Medicine of the University Hospital. Karl Ullrich’s deep interest in basic medical sciences led him to join Kurt Kramer, a well-known physiologist in Marburg, where he began by studying heart function. In 1955, Ullrich moved with Dr. Kramer to Göttingen and began his career as a renal physiologist. He developed methods necessary to quantitatively describe transport functions of renal tubules, including microcatheterization of papillary collecting ducts, beveled micropipettes for puncturing the proximal tubules and peritubular capillaries, the ‘shrinking droplet method,’ microperfusion of tubules, and microcuvettes for small sample volumes. After a stay in Chapel Hill, North Carolina, working with Carl Gottschalk and Bodil Schmidt-Nielsen, Ullrich was appointed in 1962 as full professor of physiology at the Freie Universität in Berlin. In 1967, he became a director at the Max Planck Institute of Biophysics in Frankfurt, where he worked until his retirement in December 1993. Fascinated by Homer W. Smith's book The Kidney: Structure and Function in Health and Disease and intrigued by the pioneering work of Werner Kuhn and Heinrich Wirz, Karl Ullrich began with studies on the mechanism of the concentration and dilution of urine. He found out that the osmolality of the medulla resulted from the accumulation of salt and urea, and he detected glycerophosphocholine and inositol, substances later to become known as osmolytes. Ullrich showed that medullary collecting ducts absorb sodium ions, secrete protons and ammonium ions, and participate in urea recycling. An overview of the countercurrent system became a citation classic. In Berlin, Ullrich turned his interest to ion and water transport in renal proximal tubules. Using the zero net flux concentration difference, Ullrich determined active and passive transport for sodium ions, potassium ions, and calcium ions and developed the pump-leak model for transepithelial fluxes. The driving forces for the absorption of sodium ions, chloride, bicarbonate, and urea in proximal tubules were accurately determined. In the mid-1970s and 1980s, Ullrich investigated in depth the sodium-coupled absorption for hexoses, amino acids, phosphate, sulfate, monocarboxylates, and dicarboxylates. Influenced by Ernest M. Wright, he tested chemical analogs in order to define the structural requirements for absorption in vivo. Finally, Karl Ullrich developed a zero net flux capillary stopflow perfusion method that allowed him to study short-term uptake of solutes across the contraluminal (basolateral) membrane of proximal tubule cells in the intact rat kidney. With this method, three transport systems were described—for amphiphilic organic anions (the p-aminohippurate, or PAH, transport system), dicarboxylates (the succinate transport system), and sulfate—along with a transport system for organic cations. Ullrich tested hundreds of chemical compounds, including frequently used drugs, to define their interaction with these contraluminal transport systems. Never before had transport systems in the intact tubule been tested so vigorously. As a result, Ullrich was able to define charge, charge distance, hydrophobicity, and ability to form hydrogen bridges as being important for the interaction between substrates and transporters. Karl Ullrich published about 200 original articles, reviews, and chapters for student textbooks on physiology. His brilliant research and his enormous capacity to develop and transmit new concepts attracted many colleagues from all over the world who joined Ullrich in Berlin and Frankfurt for cooperation, often resulting in lifelong friendships and scientific exchange. Many great names in renal physiology are found as authors on Ullrich’s papers. Although he continuously advised his long-term research group leaders, he never appeared as a co-author on their papers—a truly generous behavior. Ullrich received numerous prestigious honors: the Feldberg Lecture for Experimental Medicine (1961), the Homer W. Smith Award of the New York Heart Association (1975), the Walter B. Cannon Lecture of the American Physiological Society (1987), and the A.N. Richards Award of the International Society of Nephrology (1990). In addition, he received the Purkinje Medal of the Czech Academy of Sciences, the Franz Volhard Medal of the German Society of Nephrology, the Jacob Henle Medal of the Medical Faculty in Göttingen, the Medal of the Fachbereich Humanmedizin in Frankfurt, the Borelli Gold Medal of Nephrology in Naples, the Pavlov Medal of the Russian Academy of Sciences, and the Kopernikus Medal of the Polish Academy of Sciences. He earned honorary doctoral degrees from the Medical Faculties in Marburg, Berlin, and Zurich. In 1969, Karl Ullrich became a member of the Gesellschaft der Naturforscher Leopoldina, the oldest continuously existing German Academy of Sciences. He was an honorary member of the Australian and New Zealand Society of Nephrology, the American Physiological Society, the Hungarian Physiological Society, the German Society of Physiology, and the German Society of Nephrology. Based on a rigorous approach to renal physiology, Ullrich’s department was a mecca of kidney physiology. Standing on the shoulders of this giant, many of his academic pupils were able to take over leadership in physiology or nephrology. We all are deeply grateful for the continual and highly valuable support offered to us by this eminent researcher and great academic teacher. —The authors, on behalf of his friends and academic pupils