These studies were carried out in the Departement of Dermatology and Venereology, Helsinki University Central Hospital, during the years 1994-1999.
I wish to express my sincere gratitude to those who have contributed to this work:
Professors Annamari Ranki and Timo Reunala for providing excellent facilities for the studies.
Professor Jorma Keski-Oja for providing the facilities and the support that enabled me to fully concentrate in this work during the year 1996.
My supervisor, Docent Ulpu Saarialho-Kere, deserves my deepest gratitude for introducing me to the world of metalloproteinases, and guiding me through these studies. I admire her never-failing, productive enthusiasm in scientific work, and the ability to always be ready for discussions, despite the busy schedule.
Professor Juha Kere for friendly discussions, during which he offered useful pieces of his vast genetic knowledge.
Docent Arja-Leena Kariniemi for her invaluable dermatopathological knowlegde, and for her friendliness and interest in fields that extend beyond the everyday work.
Professor Aarne Oikarinen and Docent Matti Laato for kindly examining this thesis, and for their constructive comments on the text.
My co-authors, Docents Veli-Matti Kähäri and Pauli Puolakkainen, Professor William Parks, and Drs. Marja-Liisa Karjalainen-Lindsberg, Nina Johansson, Laura Ravanti, Pia Saarinen, Jorma Lauharanta, Miina Weckroth and Tomi Leivo, for pleasant and fruitful collaboration.
Dr. Kristiina Airola not only for her contribution to the lab work in these studies, but especially for her friendship, that has brightened up many days both in the lab and in the outside world.
My friends and colleagues Outi, Tiina, Erja, Hanna, Leena, Mikko S., Oona, Sari and Siru for the time shared at work, for invaluable help in solving various kinds of problems, and for lunch-breaks and free-time with vivid conversations.
The ladies in the lab: Alli, Anna-Mari, Birgitta, Kaija, Liisa S. and Marja for excellent technical help and Liisa L. for excellent secretarial help, and for their interest and caring during these years.
David Mauffret for revising the English language.
In addition, I wish to give all my dear friends, and their families warm hugs for making my spare time most enjoyable. Especially Mari deserves a big hug for sharing the ups and downs of both research and everyday life.
I most warmly thank my parents Leila and Juhani Keski-Säntti for all the love and support they have given to our family during these years. I thank my brothers Harri and Jouko, and their lovely families for caring, and for sharing many of the best moments of my life. Also, Mikko´s parents Pirkko and Pentti Vaalamo, sister Tuija and brother Jukka with their families, deserve my deepest thanks for the enjoyable times we have spent together.
Most of all, I thank Mikko, Emilia and Veikka for filling my life with love, precious moments and joy. Mikko has shared all these years with me, and his love and care have been the greatest support to all the aspects of my life.
This thesis has been financially supported by the Helsinki University Central Hospital Research Fund, The University of Helsinki, Finska Läkaresällskapet, the Paulo Foundation, the Sigrid Juselius Foundation, the Farmos Research Foundation, the Duodecim Foundation, the Finnish Dermatological Society, and the Dermatopathological Society.