[1] Charles Univ Prague, Fac Med 2, Inst Physiol, Prague 15000 5, Czech Republic
[2] Charles Univ Prague, Fac Med 2, Clin Ophthalmol, Prague 15000 5, Czech Republic
[3] Charles Univ Prague, Fac Med 2, Inst Histol & Embryol, Prague 15000 5, Czech Republic
[4] Charles Univ Prague, Fac Med 2, Inst Med Chem & Biochem, Prague 15000 5, Czech Republic
[5] Acad Sci Czech Republ, Inst Physiol, Dept Growth & Differentiat Cell Populat, Prague, Czech Republic
[6] Univ Edinburgh, Edinburgh, Midlothian, Scotland