The present study was carried out at the department of Biochemistry, University of Oulu. First of all, I wish to express my gratitude to my supervisor, Docent Oili Hietala for introducing me to the interesting world of science and her support during this work. Our project was often difficult and results kept us waiting, but there were certainly less disagreements and complaints in our lab than in labs generally. I also owe my sincere thanks to Professor Karl Tryggvason, the Head of Department in Oulu during early years and my present supervisor whose flexibility made the completion of this thesis possible. Professors Kalervo Hiltunen and Raili Myllylä, as well as other professors and group leaders, are acknowledged for the devoted cultivation of the exceptionally creative environment and modern attitude towards research work at the Department of Biochemistry.
I am grateful to professor Leena Alhonen and Docent Erkki Hölttä for their valuable comments on the manuscript, and to Dr. William Griffiths for the careful revision of the language of this thesis.
I wish to express my gratitude to all co-authors and collaborators. Particularly, I cherish the days spent in the lab with Jukka Saarimies. Without the collaboration of professor Markku Pelto-Huikko and Dr. Elena Rybnikova this thesis would never have been printed. My special thanks go to the skilful staff of the department for their assistance in technical, secretarial and administrative matters. They also formed the core of our volleyball team giving variety to the long working evenings.
I feel deep gratitude to all my colleagues and friends in Oulu, Birmingham and Stockholm. It has been a pleasure to work with them on good days and they have managed to nurse me through the worse days. I owe my very special thanks to Paula Reponen and Ari Tuuttila for their friendship and support during all the years from the early undergraduate days to the beginning of serene and happy senility. Also the wide allaround expertise of Timo Pikkarainen and creative idiosyncrasies of Ulrich Bergman are appreciated and remembered with warm gratefulness.
Finally, I feel my deepest gratitude to my family and relatives. My parents Hanna and Simo brought me up as skilfully as ever possible. My sister Pirkko, brother Pertti and sister-in law Tuija have made tireless efforts to upgrade my upbringing still little bit. Aunts Eeva and Leena and uncle Mikko as well as Lauri, Liisa and cousins have been helpful in many valuable ways.
This work was supported by grants from the Finnish Foundation for Cancer Research, the Finnish Cultural Foundation, the Ida Montin Foundation, the Paulo Foundation and the University of Oulu.
Solna, February 2002 Pekka Kilpeläinen