Kordaš, Marjan

Marjan Kordaš (Ćuprija, 17. avgusta 1931), zdravnik (dr. med), dr. znanosti, redni profesor za patološko fiziologijo (v pokoju) na Medicinski fakulteti v Ljubljani.

Rodil se je v Srbiji, od 1936 dalje pa je vseskozi živel v Sloveniji. Po maturi (I. gimnazija v Ljubljani) 1950 se je vpisal na Medicinsko fakulteto v Ljubljani (MF) in 1958 diplomiral kot dr. med. Potem ko je odslužil vojaščino, je 1959 začel delati na Inštitutu za patološko fiziologijo z nalogo, da – poleg pouka študentov medicine (predavanja, seminarji, vaje) – na tem inštitutu postavi laboratorij za elektrofiziologijo. Te raziskovalne metode se je učil na Department of Biophysics, University College London 1964/65 (Research Assistant; štipendist WHO, 10 mesecev) in 1967/68 (Research Assistant; štipendist WHO, 4 mesece) ter 1970 v Marine Biological Laboratory, Woods Hole, ZDA (Research Fellow, štipendist Sklada Borisa Kidriča, 3 mesece). 1971 je doktoriral s temo Časovni potek toka motorične ploščice pri nevromuskularnem prenosu v skeletni mišici. 1973 docent, 1977 izredni profesor, 1979 redni profesor za patološko fiziologijo. Upokojil se je 1999.
Funkcije na MF ter na Univerzi v Ljubljani (UL): predsednik Pododbora za sprejem novincev na MF (1986–92); predsednik Kadrovske komisije MF (1992–94); član Habilitacijske komisije UL (1992–94 in 1998–99); predsednik Habilitacijske komisije UL (1994–95 in 1995–98).

Za izrednega člana SAZU je bil izvoljen 6. junija 1995, za rednega člana SAZU pa 7. junija 2001.

Za eksperimentalno delo na skeletni mišici je že 1966 na Inštitutu za patološko fiziologijo MF postavil laboratorij za mikroelektrofiziologijo in kot prvi v Evropi uporabil “metodo vpete napetosti” (“voltage-clamp”). Do nekako 1980 je osnovno metodo nadgradil v nekaj različic. V enem najbolj citiranem članku iz 1969 je ovrgel dotedanje koncepte in nakazal, da se med živčno-mišičnim prenosom v postsinaptični membrani pojavi “ena sama prevodnost”, odvisna od količine sproščenega mediatorja. Tako se je zlagoma izoblikoval koncept o ionskem kanalčku oz. populaciji ionskih kanalčkov v živčno-mišičnem stiku. Sproščeni mediator nato sproži dogajanje, prek katerega se kanalčki preoblikujejo iz “zaprte” v “odprto” konformacijo.

Rezultate svojega raziskovalnega dela je Kordaš sproti objavljal v mednarodnem prostoru, večinoma v indeksiranih revijah, nekaj pa tudi kot poglavja v knjigah.

Najpomembnejša dela iz področja mikroelektrofiziologije:
Kordaš M (1969) The effect of membrane polarization on the time course of the end-plate current. J Physiol 204: 493 - 502.
Kordaš M (1970) The effect of procaine on neuromuscular transmission. J Physiol209: 698 - 699.
Kordaš M (1972a) An attempt at an analysis of the factors determining the time course of the end-plate current. I. The effects of prostigmine and of the ratio of Mg2+ to Ca2+. J Physiol 224: 317 - 332.
Kordaš M (1972b) An attempt at an analysis of the factors determining the time course of the end-plate current. II. Temperature. J Physiol 224: 333- 348.
Kordaš M, Brzin M, Majcen, Živa (1975) A comparison of the effect of cholinesterase inhibitors on end-plate current and on cholinesterase activity in frog muscle. Neuropharmacology 14: 791 - 800
Kordaš M (1977) On the role of junctional cholinesterase in determining the time course of the end-plate current. J Physiol 270: 133-150.
Citiranje do leta 1993: Indeks citiranosti: 334. Čisti citati: 572. Vsi citati 634. Celotna bibliografija obsega preko 100 bibliografskih enot. Več kot polovica del obravnava problematiko pedagoškega dela na MF na dodiplomski in podiplomski stopnji.

Poleg eksperimentalnega dela se je Kordaš tudi precej ukvarjal s simulacijo fizioloških procesov. Za pouk patološke fiziologije krvnega obtoka je s sodelavci razvil ter že 1968 objavil analogni model krvnih obtočil. Po prodoru računalniških metod v splošno uporabo je 1987 ta analogni model krvnih obtočil digitaliziral ter dopolnil 1993 in 1996. Po upokojitvi, ko ni več imel možnosti za eksperimentalno delo, se pa je v celoti posvetil simulaciji fizioloških procesov. Namreč, fiziološke sisteme je možno ponazoriti s t. i. analognim elektronskim vezjem. Slednje pa je možno precej natančno analizirati s sodobno računalniško programsko opremo.

Najpomembnejša dela iz področja simulacije fizioloških sistemov:
Kordaš M, Trontelj J, Leonardis S (1968) An electrical model of blood circulation. Med & biol Engng 6: 449 - 451.
Bošnjak R, Kordaš M (2002) Circulatory effects of internal jugular vein compression: a computer simulation study, Med. Biol. Eng. Comput. 40: 423-31.
Dolenšek J, Runovc F, Kordaš M (2005) Simulation of pulmonary ventilation and its control by negative feedback. Computers in Biology and Medicine 35: 217 - 228.
Sever M, Podnar T, Runovc F, Kordaš M (2007) Analog simulation of two clinical condition: (1) Acute left ventricle failure; (2) exercise in patient with aortic stenosis. Computers in Biology and Medicine 37: 1051 - 1062.
Dolenšek J, Podnar T, Runovc F, Kordaš M (2009) Analog simulation of aortic and of mitral regurgitation. Computers in Biology and Medicine 39: 474 - 481.
Samo Ribarič and Marjan Kordaš: Teaching cardiovascular physiology with equivalent electronic circuits in a practically oriented teaching module. Adv Physiol Educ 35: 149-160, 2011.
M. Sever, S. Ribarič, F. Runovc, M. Kordaš: Analog simulation of aortic stenosis. In: Masanori Hirota (ur.): Aortic stenosis - etiology, pathophysiology and treatment. InTech, Open Access Publisher, 2011, chapter 6, pp. 75-88.

Nagrade in odlikovanja: Nagrada Sklada Borisa Kidriča za raziskovalno delo (1976). Plaketa Univerze v Ljubljani za pedagoško delo (1993). Nosilec Reda dela z zlatim vencem (1987). Zaslužni profesor Univerze v Ljubljani (1999).

(januar 2012)

Marjan Kordaš (Ćuprija, August 17, 1931) physician (MD), DSc. Professor of Pathophysiology (retired), Faculty of Medicine in Ljubljana, Slovenia.

He was born in Serbia, but since 1936 he has been living continuously in Slovenia. After high school graduation (“Gymnasium”; I. gimnazija Ljubljana) he enrolled at the Faculty of Medicine and achieved his degree (MD) in 1958. Having finished the one-year compulsory service in the Yugoslav Army, in 1959 he started his career at the Institute of Pathophysiology. His position required him to teach medical students (lectures, seminars, practicals) of medical students, but his main duty was to set up an Electrophysiology Laboratory. To be proficient in this research method, he worked, as a WHO scholar, first at University College London as Research Assistant (1964/65, 10 months and 1967/68, 4 months) and later, as a Boris Kidrič Foundation Scholar, at Marine Biological Laboratory, Woods Hole, USA (1970, 3 months). In 1970 he achieved his Ph.D. degree, the research theme of which was titled The time course of the end-plate current during neuromuscular transmission in skeletal muscle. In 1973 Assistant Professor, in 1977 Associate Professor, in 1979 Professor of Pathophysiology. Retired in 1999.

Positions held at the Faculty of Medicine and at the University of Ljubljana: President of the Sub-Committee for newly enrolled medical students (1986 - 92); President of the Staff Committe (1992 - 94); member of the University Promotion Committee (1992 - 94 and 1998 - 99); President of the University Promotion Committee (1994 - 95 and 1995 - 1998).

Membership of the Slovenian Academy of Sciences and Arts: Associate Member since June 6, 1995; Full Member since June 7, 2001.

For the experimental work in skeletal muscle he established in 1966 his electrophysiological laboratory and - in Europe for the first time - he applied the “voltage-clamp” method. Until about 1980 the basic method was continuously upgraded. In a most frequently cited paper published in 1969 he disproved general concepts of that time and suggested that during neuromuscular transmission a “single conductance” appears, which depends on the quantity of the released transmitter. In this way he contributed to the concept of the ionic channel and population of ionic channels in neuromuscular junctions. Briefly, after transmitter is released, a process is triggered whereby channels change from the “closed” to the “open” conformation.

The results of his research have been communicated on-line, mostly in publications with international citations, or as chaptes in various textbooks.

Most relevant works in the field of microelectrophysiology:
Kordaš M (1969) The effect of membrane polarisation on the time course of the end-plate current. J Physiol 204: 493 - 502.
Kordaš M (1970) The effect of procaine on neuromuscular transmission. J Physiol 209: 698 - 699.
Kordaš M (1972a) An attempt at an analysis of the factors determining the time course of the end-plate current. I. The effects of prostigmine and of the ratio of Mg2+ to Ca2+. J Physiol 224: 317 - 332.
Kordaš M (1972b) An attempt at an analysis of the factors determining the time course of the end-plate current. II. Temperature. J Physiol 224: 333- 348.
Kordaš M, Brzin M, Majcen, Živa (1975) A comparison of the effect of cholinesterase inhibitors on end-plate current and on cholinesterase activity in frog muscle. Neuropharmacology 14: 791 - 800
Kordaš M (1977) On the role of junctional cholinesterase in determining the time course of the end-plate current. J Physiol 270: 133-150.
Citations until 1993: Citation Index: 334. Net citations: 572. All citations: 634. Total bibliography comprises more than 100 bibliographical units. More than 50 % of published works is concerned with problems about teaching at the undergraduate as well at the postgraduate level.

Apart from the experimental work Marjan Kordaš has also been concerned with simulation of physiological processes. Already in 1968 an analogue model of blood circulation, developed for teaching purposes, was published by Marjan Kordas and his coworkers. As soon as various computer methods had been introduced in general use, in 1987 this analogue model was digitalised, and later upgraded in 1993 and 1996. After retirement, when Marjan Kordaš had no more any possibility to continue his experimental work, all his efforts have been concentrated to simulation of physiological processes. Simply because physiological system can be simulated by electronic analogue circuits. The latter can be fairly accurately analysed by using modern computer programs.

Most relevant works in the field of simulation of physiological systems:
Kordaš M, Trontelj J, Leonardis S (1968) An electrical model of blood circulation. Med & biol Engng 6: 449 - 451.
Bošnjak R, Kordaš M (2002) Circulatory effects of internal jugular vein compression: a computer simulation study, Med. Biol. Eng. Comput. 40: 423-31.
Dolenšek J, Runovc F, Kordaš M (2005) Simulation of pulmonary ventilation and its control by negative feedback. Computers in Biology and Medicine 35: 217 - 228.
Sever M, Podnar T, Runovc F, Kordaš M (2007) Analogue simulation of two clinical condition: (1) Acute left ventricle failure; (2) exercise in patient with aortic stenosis. Computers in Biology and Medicine 37: 1051 - 1062.
Dolenšek J, Podnar T, Runovc F, Kordaš M (2009) Analogue simulation of aortic and of mitral regurgitation. Computers in Biology and Medicine 39: 474 - 481.
Samo Ribarič and Marjan Kordaš: Teaching cardiovascular physiology with equivalent electronic circuits in a practically oriented teaching module. Adv Physiol Educ 35: 149-160, 2011.
M. Sever, S. Ribarič, F. Runovc, M. Kordaš: Analog simulation of aortic stenosis. In: Masanori Hirota (ur.): Aortic stenosis - etiology, pathophysiology and treatment. InTech, Open Access Publisher, 2011, chapter 6, pp. 75-88.

Awards and decorations: Boris Kidrič Foundation Award for research (1976), University of Ljubljana Medal for teaching (1993). Emeritus Professor of University of Ljubljana (1999).

(January 2012)