Aradigm Corp., of Hayward, Calif., appointed Richard Thompson chairman. Also, Igor Gonda was named chief scientific officer and Stephen Farr vice president of research and development.

Arrow Therapeutics Ltd., of London, appointed Naiem Hussain chief financial officer.

Athersys Inc., of Cleveland, hired Anne Brown as senior director of intellectual property.

Aviron, of Mountain View, Calif., appointed David M. Wonnacott vice president, regulatory affairs, and Charles F. Katzer vice president, manufacturing.

Celltech plc, of Slough, UK, promoted Mark Litton to vice president, business development.

Chimeric Therapies Inc., of Laguna Niguel, Calif., named Virgil Thompson as chief executive officer.

Cholestech Corp., of Hayward Calif., named Terry Wassmann vice president of human resources.

Ciphergen Biosystems Inc., of Fremont, Calif., made Chistopher Pohl vice president of research and development, and said he will also serve as a member of Ciphergen's executive committee.

CombiMatrix Corp., of Burlingame, Calif., appointed Gerald Knudson as chairman. Knudson has been CEO since February. Also, Patrick Quarles was named president and chief operating officer and Stephen Burke was named chief financial officer. The company also appointed Patrick de Maynadier executive vice president, general counsel and corporate secretary; promoted Brooke Anderson to vice president of software development; named Edward Eadeh vice president of international business development; and hired Warren Hargis as vice president of human resources.

Cytochroma Inc., of Kingston, Ontario, appointed Robert Foldes as president and chief executive officer.

Cytyc Corp., of Boxborough, Mass., promoted Daniel Levangie to executive vice president.

Derma Sciences Inc., of Princeton, N.J. appointed John Yetter chief financial officer.

Diversa Corp., of San Diego, made Mervyn Bibb director of pharmaceutical pathway expression and Melvin Simon, co-founder of Diversa, resident scientific adviser.

Ecopia BioSciences Inc., named Gary Littlejohn executive vice president and chief financial officer.

Enzon Inc., of Piscataway, N.J., said Peter Tombros, president and CEO, signed an extension of his tenure through 2003.

Genelabs Technologies Inc., of Redwood City, Calif., hired Lynn Hughes as vice president of human resources and Ming Chen as vice president of research.

HTS Biosystems Inc., of Eagan, Minn., named Enrico Picozza chief operating officer and executive vice president of business development.

MetaMorphix Inc., appointed Ronald L. Stotish as vice president, research and development.

Medarex Inc., of Princeton, N.J., named James Cornett and Ronald Pepin vice presidents, business development, of GenPharm International Inc. GenPharm is a wholly owned subsidiary of Medarex.

MetaMorphix Inc., of Baltimore, appointed Ronald Stotish as vice president, research and development.

MitoKor Inc., of San Diego, added Alan Rosenthal to its board of directors. Rosenthal currently is vice president of scientific affairs and technology at Abbott Laboratories.

Myriad Genetics Inc., of Salt Lake City, named Sudhir Sahasrabudhe executive vice president of research and development.

NeoTherapeutics Inc., of Irvine, Calif., named Rajesh Shrotriya president.

Novo Nordisk AS, of Bagsvaerd, Denmark, said Martin Soeters will take over as president of Novo Nordisk Pharmaceuticals Inc., of Princeton, N.J., and as head of its North American region.

OSI Pharmaceuticals Inc., of Uniondale, N.Y., elected Colin Goddard, currently president and CEO, chairman of the board.

Oxis International Inc., of Portland, Ore., named Joseph Bozman Jr. to its board of directors.

Oxxon Pharmaccines Ltd., of Oxford, England, appointed Alan Williamson as non-executive director.

Pan Pacific Pharmaceuticals Inc., of Menlo Park, Calif., made Rene Braeckman vice president, drug development.

Panacea Pharmaceuticals Inc., of Rockville, Md., announced Carl Merril as chairman of the company's scientific advisory board.