Apollo Medical Holdings Inc. has appointed Dr. Thomas Lam to its board, the company announced Tuesday. The Glendale doctors group and health management company, signed an investment agreement last year with Network Medical Management Inc. in Alhambra, a health care management firm. Lam is chief executive of Network Medical. It currently manages care for more than 600,000 patients in California. Born in Hong Kong and raised in California, Lam is a gastroenterologist who also serves as chief financial officer at Allied Pacific of California IPA, a large doctors group that has more than 500,000 enrolled patients. “We are thrilled to welcome Tom to our board of directors and look forward to our partnership with Network Medical Management,” Dr. Warren Hosseinion, ApolloMed’s chief executive, said in a statement. “He brings a wealth of industry and financial experience from his successful career as CEO and CFO of health care enterprises with over $500 million in revenues.” Shares closed up 1 cent or a fraction of 1 percent to $5.51 on the over-the-counter market.