New positions
* University of Baltimore has hired Neil W. Didriksen as vice president of institutional advancement. He will oversee the school's fund-raising and alumni programs.
* American Red Cross, Central Maryland chapter, appointed Pat Lakatta director of communications and Eugena Blythe managing director for human resources.
* Columbia Computers Inc. named Carl Kasseboom service manager and added Bob Matthews, Joe Jakub and Albert Blaize to its sales staff.
Advertising and PR
* W. B. Doner & Co. has chosen Bruce Broder senior vice president and creative director.
* Impax Inc., a national public relations firm based in Hunt Valley, has named David Green chief executive officer and Josh Green president.
* BB&Y; Inc., advertising and public relations, has added Eden Stotsky to the staff as an administrative account executive.
* Harvey & Daughters, the communications and package design firm located in Cockeysville, has named Audrey Dufresne a graphics designer, Michael Kreitz computer graphics artist and Stephanie Kermisch production manager.
Financial services
* Potomac Valley Bank has named Kenneth C. Cook president and chief executive officer and R. Dennis Homberg vice chairman.
Professional
* Marshall Craft Associates, a Baltimore-based architects and interior design firm, announced that Susan D. Guggenheim joined its interior design and space planning department.
* James Posey Associates Inc. named Karl Gumnick project electrical engineer and Shirley Neale as senior marketing coordinator.
* Cochran, Stephenson & Donkervoet promoted David S. Segmiller and Diane DiFerdinando to senior associate. Named associates were: Frederick J. Hiser, Charles M. Hovancik III, Michael A. Miller, Kevin C. Ross and Karyn J. Schmitt.
Legal and insurance
* Piper & Marbury announced that Joyce J. Gorman, Joseph A. Fanone, Mitchell S. Marder and John Washington Jr. have joined its Washington office.
* AVEMCO Corp. elected Thomas L. Hudson vice president, business development for the Frederick-based insurer.
Health care
* Tri-Home Health Care & Services has chosen Sue Niewenhous as director of operations.
* Vantage House named Kay Trantham as director of nursing.
Commercial real estate
* RTKL Associates elected David J. Brotman vice chairman and appointed Randall S. Pace as controller.
* Beacon Management Co. named Jennifer G. Arhens as leasing agent for the Candler Building.