1. Institute of Biochemistry, Medical Faculty (Charité), Humboldt University Berlin, Hessische Str. 3-4, Berlin D(O)-1040, Germany
2. lnstitute of Veterinary Pharmacology and Toxicology, Free University Berlin, Koserstr., Berlin 33 D-1000, Germany
3. Herzog-Julius-Hospital, Kurhausstr, 13–17, Bad Harzburg D-3388, Germany