View source for Coen Hemker

{{Short description|Dutch biochemist and academic administrator}}
{{Infobox academic
| name              = Coen Hemker
| image             =
| caption           =
| birth_name        = Hendrik Coenraad Hemker
| birth_date        = {{birth date and age|1934|07|21|df=y}}
| birth_place       = [[Amsterdam]], the Netherlands
| death_date        =
| death_place       =
| nationality       = Dutch
| occupation        = Biochemist
| spouse            =
| awards            = [[Ernst Jung Prize|Ernst Jung Prize for Medicine]] (1985)
| alma_mater        = [[University of Amsterdam]]
| thesis_title      = Mechanisme van de werking van ontkoppelende fenolen op de ademhalingsketen-fosforylering
| thesis_url        =
| thesis_year       = 1962
| doctoral_advisor  = [[Edward Slater]]
| influences        =
| workplaces        = [[Leiden University]], [[Maastricht University]]
| doctoral_students =
| notable_students  =
| main_interests    = [[thrombosis]], [[hemostasis]]
| notable_works     =
| notable_ideas     =
| influenced        =
| signature         =
| signature_size    =
| footnotes         =
}}
'''Hendrik Coenraad''' '''"Coen"''' '''Hemker''' (born 21 July 1934) is a Dutch biochemist and academic administrator. He was one of the founders of [[Maastricht University]] and was [[List of rectores magnifici of Maastricht University|its ''rector magnificus'']] from 1982 to 1984. He was a professor of biochemistry from 1975 until 1999. In his research he has mainly studied [[thrombosis]] and [[hemostasis]].
==Early life and career==
Hemker was born on 21 July 1934 in [[Amsterdam]].<ref name="KaaKaa2008">{{cite book|author1=D. J. van de Kaa|author2=Kaa|author3=Y. de Roo|title=De Leden Van de Koninklijke Nederlandse Akademie Van Wetenschappen: Een Demografisch Perspectief: 1808 Tot 2008|url=https://books.google.com/books?id=gzNvCGJEGCYC&pg=PA288|date=19 December 2008|publisher=Amsterdam University Press|isbn=978-90-6984-552-4|page=288}}</ref> With his mother being a heart patient and his father spending a lot of time on his hobbies, Hemker frequently looked after his four younger brothers. He subsequently wanted to study [[pediatrics]] but was advised by Dutch pediatrician {{ill|Simon van Creveld|nl||de||}} to study [[biochemistry]] for a year.<ref name="mt">{{cite web|last=Timmermans |first=Maurice |url=https://www.observantonline.nl/Home/Artikelen/articleType/ArticleView/articleId/10258/Hij-was-als-een-vaderlijke-vriend-voor-me |archive-url=https://web.archive.org/web/20201107135948/https://www.observantonline.nl/Home/Artikelen/articleType/ArticleView/articleId/10258/Hij-was-als-een-vaderlijke-vriend-voor-me |title="Hij was als een vaderlijke vriend voor me" |language=nl |publisher=Observant Online |date=6 January 2016 |archive-date=7 November 2020}}</ref> Hemker obtained his medical degree from the [[University of Amsterdam]] in 1959.<ref name="Green2020">{{cite book|author=David Green|title=The Heparins: Basic and Clinical Aspects|url=https://books.google.com/books?id=QyrJDwAAQBAJ&pg=PA13|date=13 January 2020|publisher=Elsevier Science|isbn=978-0-12-819069-2|page=13}}</ref><ref name="ch">{{cite web|url=http://www.coenhemker.nl/coen_hemker.php |url-status=dead |archive-url=https://web.archive.org/web/20161109104143/http://www.coenhemker.nl/coen_hemker.php |title=About |publisher=coenhemker.nl |date= |archive-date=9 November 2016}}</ref> Academically he performed well and he was asked to continue his studies so he could obtain a PhD. By this time he thoroughly liked performing research and accepted the offer.<ref name="mt"/> He obtained his PhD in biochemistry in 1962 at the University of Amsterdam under [[Edward Slater]] with a thesis titled: ''Mechanisme van de werking van ontkoppelende fenolen op de ademhalingsketen-fosforylering''.<ref name="Green2020"/><ref>{{cite web|url=http://www.albumacademicum.uva.nl/cgi/b/bib/bib-idx?type=simple;lang=nl;c=ap;rgn1=entirerecord;q1=Hemker;x=0;y=0;cc=ap;view=reslist;sort=achternaam;fmt=long;page=reslist;start=3;size=1 |archive-url=https://web.archive.org/web/20201107140658/http://www.albumacademicum.uva.nl/cgi/b/bib/bib-idx?type=simple&lang=nl&c=ap&rgn1=entirerecord&q1=Hemker&x=0&y=0&cc=ap&view=reslist&sort=achternaam&fmt=long&page=reslist&start=3&size=1 |title=H.C. Hemker, 1934 - |language=nl |publisher=University of Amsterdam |date= |archive-date=7 November 2020}}</ref>
Hemker subsequently started his specialist training to become a pediatrician but stopped as he preferred doing research. He was then hired as a researcher at the [[hemostasis]] and [[thrombosis]] department of [[Leiden University]]. While in this position he was sent to [[Oxford]] for further training where he met [[Robert Gwyn Macfarlane]]. Macfarlane had developed a first theory of [[coagulation]]. Hemker doubted the validity of the theory and thought one of the [[enzyme]]s played a different role. The two men found Hemker's idea was correct and they subsequently published their findings in ''[[Nature (journal)|Nature]]''.<ref name="mt"/>
During the 1960s he worked on [[vitamin K]] research under professor E.A. Loeliger. He found a coagulant factor only occurring with the use of [[vitamin K antagonist]]s or a vitamin K deficiency.<ref name="ntvg">{{cite web|url=https://www.ntvg.nl/system/files/publications/1968121560008a.pdf |archive-url=https://web.archive.org/web/20201107161101/https://www.ntvg.nl/system/files/publications/1968121560008a.pdf |title=Leidse lector Dr. H.C. Hemker wint Prix Européen Ganassini met stollingsonderzoek |language=nl |publisher=Nederlands Tijdschrift voor Geneeskunde |date=23 November 1968 |archive-date=7 November 2020}}</ref> Hemker became a lector of [[cardiology]] and professor of [[internal medicine]] at [[Leiden University]] in 1968.<ref name="ul">{{cite web|url=https://hoogleraren.leidenuniv.nl/id/1071 |archive-url=https://web.archive.org/web/20201107140623/https://hoogleraren.leidenuniv.nl/id/1071 |title=Hendrik Coenraad Hemker |language=nl |publisher=Leiden University |date= |archive-date=7 November 2020}}</ref><ref name="mu"/>
==Career at Maastricht University==
In the early 1970s, there were plans to establish a new university in the Netherlands, with Maastricht being named as a possible location. In 1973 Hemker was asked to join the project by political proponents of the plan, politician {{ill|Sjeng Tans|nl}} and Maastricht mayor {{ill|Fons Baeten|nl}}.<ref name="mt"/> In 1974 he was appointed and became part of a group of seven professors that prepared the founding of the Faculty of Medicine at the Rijksuniversiteit Limburg (later renamed Maastricht University).<ref name="mt"/><ref name="mu"/><ref name="bos">{{cite web|last=Bos |first=Wammes |url=https://www.observantonline.nl/Home/Artikelen/articleType/ArticleView/articleId/17045/Besturen-is-zo-weinig-interessant-Research-is-zo-veel-boeiender |archive-url=https://web.archive.org/web/20201107140137/https://www.observantonline.nl/Home/Artikelen/articleType/ArticleView/articleId/17045/Besturen-is-zo-weinig-interessant-Research-is-zo-veel-boeiender |title="Besturen is zó weinig interessant! Research is zó veel boeiender!" |language=nl |publisher=Observant Online |date=15 May 2019 |archive-date=7 November 2020}}</ref> The group was responsible for the forming of the eight faculty of medicine in the Netherlands, but when their work commenced the urgent need for the faculty was already diminished which led to the search for a different profile for the university as compared to others. This was found in first line care, [[family medicine]], and a new education concept. Hemker found that research did not receive sufficient attention.<ref name="bos"/> Hemker led a research group at Leiden University until 1975 when he formally moved to Maastricht University.<ref name="Green2020"/> At that point he became chair of the biochemistry department.<ref name="mu"/> At Maastricht his research group studied [[thrombosis]] and [[hemostasis]].<ref name="Green2020"/> In 1976 he was the first promotor of a doctorate at Maastricht University.<ref name="mu">{{cite web|url=https://www.maastrichtuniversity.nl/news/tans-medal-prof-coen-hemker |archive-url=https://web.archive.org/web/20201107135734/https://www.maastrichtuniversity.nl/news/tans-medal-prof-coen-hemker |title=Tans Medal for prof. Coen Hemker |publisher=Maastricht University |date=17 May 2019 |archive-date=7 November 2020}}</ref> During his time at Maastricht [[problem-based learning]] was considered innovative at the institute, although Hemker was initially positive about this he later became neutral to negative on the approach.<ref name="mu"/><ref name="bos"/><ref>{{cite web|url=https://www.youtube.com/watch?v=gstueOhacrQ&ab_channel=MaastrichtUniversity&t=6m21s |title=Interview with Coen Hemker, former rector of Maastricht University - a video portrait |publisher=Maastricht University via YouTube |date=12 January 2016 |access-date=14 November 2020}}</ref> Between 1976 and 1985 Hemker was concurrently working as an unpaid part-time professor of [[biochemistry]] at Leiden University.<ref name="ul"/>
In the early 1980s, the economic outlook in the Netherlands was negative and Maastricht University was not yet perceived to be a fully qualified university by other universities and the political establishment and there was fear of budget cuts or even the disestablishment of the institute. Hemker put his own name forward for the position of [[List of rectores magnifici of Maastricht University|''rector magnifici'' of Maastricht University]] to strengthen the scientific profile of the university.<ref name="bos"/> Hemker has stated he took the opportunity to show the importance of research at a time when the university was focused on education.<ref name="mt"/> The university board of directors, led by Rob van den Biggelaar, did not look favorably upon his nomination. As the college of deans supported Hemker he obtained the position and served as rector from 1982 to 1984.<ref name="mu"/><ref name="bos"/> Six months after laying down his position as rector Hemker was asked by [[Wim Deetman]] the [[List of Ministers of Education of the Netherlands|Dutch Minister of Education and Sciences]] to become chairman of the university board of directors. He declined as he wanted to focus on his research.<ref name="mt"/><ref name="bos"/>
After 1984 he took a sabbatical and became a visiting professor at the [[Paris Descartes University]], [[Pierre and Marie Curie University]] and the [[Collège de France]] in Paris.<ref name="Green2020"/><ref name="ch"/><ref name="bos"/> During 1988 he started working full-time at Maastricht University again.<ref name="ch"/> In 1995 he academically clashed with one of his colleagues in such a way that the matter was brought before the university board. Hemker was subsequently reprimanded for not having separated his own business venture sufficiently from his work in the faculty. Hemker subsequently stated that he had been too lax with his administrative obligations.<ref name="bos"/> He was an affiliate professor of internal medicine at [[Icahn School of Medicine at Mount Sinai|Mount Sinai School of Medicine]] between 1995 and 2005.<ref name="Green2020"/> Hemker officially retired from Maastricht University in 1999.<ref name="mu"/> The Hemker Fund was established in his name to promote scholarship into thrombosis and hemostasis.<ref name="ufl">{{cite web|url=https://www.ufl-swol.nl/fonds/hemker-fonds/ |archive-url=https://web.archive.org/web/20190503113513/https://www.ufl-swol.nl/fonds/hemker-fonds/ |title=Hemker Fonds |language=nl |publisher=Universiteitsfonds Limburg - SWOL |date= |archive-date=3 May 2019}}</ref> In 2009 a lecture hall at Maastricht University was named after him.<ref name="mu"/> During his career Hemker was (co-)promotor of 70 PhD's, including that of his own father when he was 70 years old.<ref name="mt"/><ref name="mu"/>
==Research==
In 1968 Hemker, in collaboration with Prof. R.G.Macfarlane (Oxford), found that prothrombin is converted into thrombin by two clotting proteins (factors Xa and Va) adsorbed next to each other on a membrane surface.<ref>Hemker HC, Esnouf MP, Hemker PW, Swart AC, Macfarlane RG: Formation of prothrombin converting activity. Nature 1967, 215:248-51.</ref> In the same year that a similar mechanism describes how the antihemophilic factors (Factors VIIa and IXa) act.<ref>Hemker HC, Kahn MJ: Reaction sequence of blood coagulation. Nature 1967, 215:1201-2.</ref> The detailed enzyme kinetics of these interactions was investigated later in collaboration with Rosing, Tans and Van Dieijen.<ref>Rosing J, Tans G, Govers-Riemslag JW, Zwaal RF, Hemker HC: The role of phospholipids and factor Va in the prothrombinase complex. J Biol Chem 1980, 255:274-83.</ref> The role of blood platelets in these processes was investigated in his lab by the groups of Zwaal <ref>Bevers EM, Comfurius P, van Rijn JL, Hemker HC, Zwaal RF: Generation of prothrombin-converting activity and the exposure of phosphatidylserine at the outer surface of platelets. Eur J Biochem 1982, 122:429-36.</ref> and Béguin.<ref>Beguin S, Kumar R, Keularts I, Seligsohn U, Coller BS, Hemker HC: Fibrin-dependent platelet procoagulant activity requires GPIb receptors and von Willebrand factor. Blood 1999, 93:564-70. </ref>
A second line of research is the mode of action of antithrombotic drugs, both vitamin K antagonists<ref>Hemker HC, Veltkamp JJ, Hensen A, Loeliger EA: Nature of Prothrombin Biosynthesis: Preprothrombinaemia in Vitamin K-Deficiency. Nature 1963, 200:589-90.</ref> and heparins.<ref>Muller AD, van Doorm JM, Hemker HC: Heparin-like inhibitor of blood coagulation in normal newborn. Nature 1977, 267:616-7. </ref><ref>Hemker HC, Al Dieri R, Beguin S: Heparins: A Shift of Paradigm. Front Med (Lausanne) 2019, 6:254.</ref>
A third main subject developed in collaboration with S.Béguin, is the invention of an automated thrombin generation test as sensitive probe for the function of the hemostatic power and thrombotic tendency of the blood.<ref>Hemker HC, Wielders S, Kessels H, Beguin S: Continuous registration of thrombin generation in plasma, its use for the determination of the thrombin potential. Thromb Haemost 1993, 70:617-24.</ref><ref>Hemker HC, Giesen P, Al Dieri R, Regnault V, de Smedt E, Wagenvoord R, Lecompte T, Beguin S: Calibrated automated thrombin generation measurement in clotting plasma. Pathophysiol Haemost Thromb 2003, 33:4-15</ref>
Hemker has more than 500 scientific publications to his name and holds several dozen patents.<ref>David Green (13 January 2020). The Heparins: Basic and Clinical Aspects. Elsevier Science. p. 13. ISBN 978-0-12-819069-2.</ref><ref>"Tans Medal for prof. Coen Hemker". Maastricht University. 17 May 2019. Archived from the original on 7 November 2020.</ref> He was the founder of the company Synapse, at which he continued to work after his retirement from Maastricht University.<ref>"Tans Medal for prof. Coen Hemker". Maastricht University. 17 May 2019. Archived from the original on 7 November 2020.</ref>
==Awards and honours==
Hemker was the winner of the 1968 Prix Européen Ganassini for his research on vitamin K coagulants.<ref name="ntvg"/> In 1985 he was recipient of the [[Ernst Jung Prize|Ernst Jung Prize for Medicine]].<ref>{{cite web|url=https://jung-stiftung.de/en/the-awards/ernst-jung-prize-for-medicine/laureates-1976-to-2018/ |archive-url=https://web.archive.org/web/20200331090401/https://jung-stiftung.de/en/the-awards/ernst-jung-prize-for-medicine/laureates-1976-to-2018/ |title=Laureates 1976 to 2018 |publisher=Ernst Jung Foundation |date= |archive-date=31 March 2020}}</ref> Hemker was elected a member of the [[Royal Netherlands Academy of Arts and Sciences]] in 1987.<ref>{{cite web|url=https://www.knaw.nl/en/members/members/4239 |archive-url=https://web.archive.org/web/20200924092751/https://www.knaw.nl/en/members/members/4239 |title=Coen Hemker |publisher=Royal Netherlands Academy of Arts and Sciences |date= |archive-date=24 September 2020}}</ref> In the same year he was named a commander of the [[Ordre des Palmes académiques]].<ref name="Green2020"/><ref name="ae"/> Hemker was elected a member of the [[Academia Europaea]] in 1990.<ref name="ae">{{cite web|url=https://www.ae-info.org/ae/Member/Hemker_Coenraad |archive-url=https://web.archive.org/web/20190401120808/https://www.ae-info.org/ae/Member/Hemker_Coenraad |title=Coenraad Hemker |publisher=Academia Europaea |date= |archive-date=1 April 2019}}</ref> He became a Chevalier in the [[Legion of Honour]] in 1990.<ref name="Green2020"/><ref name="ae"/> Hemker became a foreign honorary member of the {{ill|Koninklijke Academie voor Geneeskunde van België|nl}} in 1991.<ref name="ae"/><ref>{{cite web|url=https://www.academiegeneeskunde.be/ereleden |archive-url=https://web.archive.org/web/20200925102111/https://www.academiegeneeskunde.be/ereleden |title=Ereleden |language=nl |publisher=Koninklijke Academie voor Geneeskunde van België |date= |archive-date=25 September 2020}}</ref> In 2000 he was made a Knight of the [[Order of the Netherlands Lion]].<ref>{{cite web|url=https://www.ntvg.nl/artikelen/personalia-6856 |archive-url=https://web.archive.org/web/20201107153148/https://www.ntvg.nl/artikelen/personalia-6856 |title=Personalia |language=nl |publisher=Nederlands Tijdschrift voor Geneeskunde |date=4 August 2000 |archive-date=7 November 2020}}</ref> In 2001 Hemker became a foreign member of the French [[Académie Nationale de Médecine]].<ref name="ae"/> He was promoted to Officier in the Legion of Honour in 2011.<ref name="mu"/> In 2019 Hemker won the Dr. J.G.H. Tans Medal, the highest award of Maastricht University.<ref name="mu"/>
==Personal life==
Hemker's wife is a psychiatrist and psychoanalyst.<ref name="bos"/> During the late 1980s Hemker suffered from severe [[ulcerative colitis]], which led to him losing 20 kilograms and it nearly killed him. In an operation his [[large intestine]] was removed and Hemker subsequently recovered.<ref name="bos"/> Hemker wrote a cook book with chef Jacques Zeguers.<ref name="mt"/><ref name="bos"/>
==References==
{{Reflist}}
{{Authority control}}
{{DEFAULTSORT:Hemker, Coen}}
[[Category:1934 births]]
[[Category:Living people]]
[[Category:Commandeurs of the Ordre des Palmes Académiques]]
[[Category:Dutch biochemists]]
[[Category:Knights of the Order of the Netherlands Lion]]
[[Category:Academic staff of Leiden University]]
[[Category:Academic staff of Maastricht University]]
[[Category:Members of Academia Europaea]]
[[Category:Members of the Royal Netherlands Academy of Arts and Sciences]]
[[Category:Officers of the Legion of Honour]]
[[Category:Rectors of universities in the Netherlands]]
[[Category:Scientists from Amsterdam]]
[[Category:University of Amsterdam alumni]]