ROBERT SIEGEL, HOST:
President Obama closed his news conference today with a tribute to some of those who were killed when that jet was shot down in Ukraine.
PRESIDENT BARACK OBAMA: On board Malaysian Airlines flight MH17, there were apparently 100 researchers and advocates traveling to an international conference in Australia dedicated to combating AIDS - HIV. These were men and women who had dedicated their own lives to saving the lives of others and they were taken from us in a senseless act of violence.
SIEGEL: Doctor Joep Lange was one of those passengers - a world renowned AIDS researcher. He had studied the disease since the early 1980s.
HELENE GAYLE: He was somebody who could connect the dots between the different aspects of the HIV bite.
AUDIE CORNISH, HOST:
Helene Gayle served as president of the International AIDS Society, a position she took over from Lange.
GAYLE: So there are some people who are just clinicians. There are some people who are just researchers or just on the prevention and behavioral side or the social side. You know, he really understood it all.
CORNISH: She says Lange used that credibility to build bridges between researchers and patients living with HIV and between activists and drug companies. Gayle credits him with fighting to lower the cost of treatment. He also launched the PharmAccess Foundation to try to put more doctors and nurses in sub-Saharan Africa.
SIEGEL: On top of that, she says, he was a kind, good man who insisted on making her frequent layovers in Amsterdam a little more comfortable.
GAYLE: He would come to the airport, pick me up at six o'clock in the morning, take me to his house. We'd have a cup of coffee, take a stroll - gave me a chance to take a shower, maybe even a quick nap. And then he'd take me back to the airport.
SIEGEL: Joep Lange was also the father of five daughters.
CORNISH: He was traveling with his longtime partner, Jacqueline van Tongeren, to Melbourne for the 20th International AIDS Conference.
SIEGEL: From NPR News, this is ALL THINGS CONSIDERED. I'm Robert Siegel. Transcript provided by NPR, Copyright NPR.