NEW YORK—GolinHarris has appointed Gaston Terrones Dimant as executive director and corporate practice leader in New York. He joins GolinHarris' Catalyst community, the agency's specialist team responsible for driving the integrated execution of client campaigns. Prior to joining GolinHarris, Terrones Dimant was senior vice president of corporate communications at Edelman in New York where he managed communications programs on multiple financial and professional services clients, including Citigroup and Shearman & Sterling.

TORONTO—MSLGroup has appointed Cameron Summers as senior vice president corporate and public affairs and deputy managing director of MSLGroup in Canada, and Tara Hunt as the social digital leader for Canada. Summers is a public policy expert with 18 years of experience, who most recently served as vice president of public affairs at Edelman. Hunt previously led Justin Trudeau's social media campaign during the federal Liberal Leadership race in 2013.

VIENNA, VA—Buffalo Communications, the global golf, sport and lifestyle public relations firm, has promoted Tom Williams to senior vice president. Williams will continue to lead the agency’s products group while playing key roles in corporate strategy and business development.

DENVER—Boom Broadcast, a specialty provider of broadcast and online media relations services, has hired Susan Sikora as senior vice president of business development. Based in Raleigh, NC, Sikora comes from Conduit Health Communications, which she founded in 2008 following a six-year tenure in global PR at pharmaceutical giant GlaxoSmithKline.