DEUTSCHES ÄRZTEBLATT INTERNATIONAL is a peer-reviewed, weekly, open-access, internet journal of medicine and public health. It is the international (English) version of the science section of Deutsches Ärzteblatt, the official journal of the German Medical Association (Bundesärztekammer) and the National Association of Statutory Health Insurance Physicians (Kassenärztliche Bundesvereinigung).

CHIEF SCIENTIFIC EDITOR: Priv.-Doz. Dr. Christopher Baethge

DEPUTY SCIENTIFIC EDITOR: Prof. Dr. Dr. Remschmidt, Marburg, Child and Adolescent Psychiatry

EDITORIAL BOARD:
Prof. Dr. Heinz-Harald Abholz, Düsseldorf, Primary Care Medicine
Prof. Dr. Friedhelm Beyersdorf, Freiburg, Surgery
Prof. Dr. Maria Blettner, Mainz, Epidemiology and Statisitics
Prof. Dr. Volker Budach, Berlin, Radiotherapy
Prof. Dr. Ingolf Cascorbi, Kiel, Pharmacology
Prof. Dr. Marianne Dieterich, Mainz, Neurology
Prof. Dr. Peer Eysel, Köln, Orthopedics
Prof. Dr. Klaus Friese, München, Obstetrics and Gynecology
Prof. Dr. Rolf W. Günther, Aachen, Radiology
Prof. Dr. Andreas Heinz, Berlin, Psychiatry
Prof. Dr. Ulrich Keilholz, Berlin, Oncology
Prof. Dr. Günter K. Krieglstein, Köln, Ophthamology
Prof. Dr. Dieter Leyk, Cologne/Koblenz, Sports Medicine
Prof. Dr. Wolf-Dieter Ludwig, Berlin, Hematology, Pharmacology
Prof. Dr. Joachim Mössner, Leipzig, Gastroenterology
Prof. Dr. Peter Neuhaus, Berlin, Surgery
Prof. Dr. Georg Peters, Münster, Microbiology, Hygiene
Prof. Dr. Peter Propping, Bonn, Genetics
Prof. Dr. Markus A. Rothschild, Köln, Forensic Medicine
Prof. Dr. Herbert Rübben, Essen, Urology
Prof. Dr. Andrea Tannapfel, Bochum, Pathology
Prof. Dr. Tobias Welte, Hannover, Pneumology
Prof. Dr. Karl Werdan, Halle, Cardiology
Prof. Dr. Renate Wrbitzky, Hannover, Occupational Medicine
Prof. Dr. Hans-Peter Zenner, Tübingen, Otolaryngology
Prof. Dr. Josef Zentner, Freiburg, Neurosurgery
Prof. Dr. Michael Zenz, Bochum, Anesthesiology and Intensive Care MEdicine
Prof. Dr. Detlef Zillikens, Lübeck, Dermatology
Prof. Dr. Klaus-Peter Zimmer, Gießen, Pediatrics

EDITOR-IN-CHIEF, Deutsches Ärzteblatt: Heinz Stüwe,responsible in law for overall editorial content

EDITORIAL STAFF: Elke Bartholomäus M.A., Dr. Sandra Goldbeck-Wood, Dr. Svenja Ludwig, Catrin Marx, Dr. sc. nat. Stephan Mertens, Dipl.-Biol. Gabriele Seger

PRODUCTION DEPARTMENT: Herbert Moll (chief), Ralf Brunner, Michael Peters

WEB EDITOR AND ARCHIVE ADMINISTRATOR: Michael Schmedt (chief)

ADDRESS OF THE EDITORIAL OFFICES: Ottostraße 12, 50859 Cologne, Germany; P.O. Box 40 02 43, 50832 Cologne, Germany; phone: +49 (0) 22 34/70 11-1 20; fax: +49 (0) 22 34/70 11-1 42; email: medwiss@aerzteblatt.de; www.aerzteblatt-international.de

The instructions for authors are available at: www.aerzteblatt-international.de/int/forauthors.asp

Articles appearing in DEUTSCHES ÄRZTEBLATT INTERNATIONAL are indexed in the following databases: Carelit, CINAHL, Compendex, DOAJ, EMBASE, EMNursing, GEOBASE, HINARI, Index Copernicus, Medline, Medpilot, PsycINFO, Science Citation Index expanded and Scopus.

Articles represent the views of authors and not necessarily those of the editorial team. Any quoted dosages, indications or applications of treatments, particularly in the case of newly licensed products, must be checked against information supplied by the manufacturer.
DEUTSCHES ÄRZTEBLATT INTERNATIONAL reserves all rights, in particular the right to reproduce, microcopy, save to electronic databases, or translate into other languages, material published therein. Reprints and inclusion in electronic databases is permitted, whether wholly or in part, only with the permission of the publisher. We cannot guarantee to return unsolicited, submitted manuscripts. Submission of material to the editorial team implies agreement to its full or partial publication unless wishes to the contrary are clearly expressed at the time of submission.

CHIEF EXECUTIVE OFFICERS DEUTSCHER ÄRZTE-VERLAG GMBH: Jürgen Führer, Dieter Weber

BUSINESS MANAGER PUBLISHING GROUP: Rüdiger Sprunkel

PUBLISHER: Deutscher Ärzte-Verlag GmbH, Dieselstraße 2, 50859 Cologne, Germany; P.O. Box 40 02 54, 50832 Cologne, Germany; phone: +49 (0) 22 34/70 11-0; fax: +49 (0) 22 34/70 11-4 60, www.aerzteblatt.de; email: verlag@aerzteblatt.de

TAX REFERENCE: USt. IdNr. DE 123474208

PRODUCTION: L. N. Schaffrath DruckMedien, Geldern

ISSN 1866-0452