[1] Walter Sisulu Univ PBX1, Dept Human Biol, Fac Hlth Sci, ZA-5117 Mthatha, South Africa
[2] Walter Sisulu Univ PBX1, Dept Biol & Environm Sci, Fac Nat Sci, ZA-5117R Mthatha, South Africa
[3] Walter Sisulu Univ PBX1, MBCHB Programme, Fac Hlth Sci, ZA-5117 Mthatha, South Africa
[4] Med Univ Graz, Physiol Div, Otto Loewi Res Ctr Vasc Biol Immunol & Inflammat, Neue Stiftingtalstr 6, A-8036 Graz, Austria