Helmus, Janine
Zorell, Sarah
Bajanowski, Thomas
Poetsch, Micaela https://orcid.org/0000-0003-1364-6487
Article History
Received: 29 June 2017
Accepted: 19 September 2017
First Online: 30 September 2017
Compliance with ethical standards
: All samples were obtained after informed consent and with approval of the Medical Ethics Committee at the University of Duisburg-Essen in accordance with the Declaration of Helsinki and national laws.
: The authors declare that they have no conflict of interest.