Seven scientists have won prestigious medical awards for development of liver transplantation, discoveries about the inner workings of cells, and leadership in biomedical science.

The Albert and Mary Lasker Foundation announced the winners Monday. The prizes, worth $250,000 for each of three categories, will be presented in New York on Sept. 21.

The Lasker award for clinical medical research was shared by Dr. Thomas Starzl of the University of Pittsburgh and Dr. Roy Calne, an emeritus professor at Cambridge University, for developing liver transplantation.

Their work on the surgical procedure and treatment to prevent organ rejection was done initially in dogs. In 1960, Calne's dog experiments demonstrated for the first time that a drug could fend off organ rejection. Starzl attempted the first human liver transplant in 1963. That patient died during the procedure. The next several patients died within weeks of their surgeries, but they showed that transplanted livers could function.

James Till, MD, left, and Ernest McCulloch, MD, both from the University of Toronto, won the 2005 Lasker award for Basic Medical Research 2005 for their ground-breaking work in stem cell research. James Till, MD, left, and Ernest McCulloch, MD, both from the University of Toronto, won the 2005 Lasker award for Basic Medical Research 2005 for their ground-breaking work in stem cell research. (John Smock/Associated Press)

Both men pursued further research, especially in blocking rejection. Liver transplantation finally gained acceptance in the 1980s, and it has "restored normal life to thousands of patients," the foundation said.

The award for basic medical research was shared by Michael Sheetz of Columbia University, James Spudich of Stanford University, and Ronald Vale of the University of California, San Francisco. They were honoured for discoveries about the biological machines that make muscles contract and transport cargos within cells. Their work laid the foundation for research into treatments for conditions including cancer and a heart disorder that can kill young athletes, the foundation said.

The award for special achievement in medical science was shared by Donald Brown of the Carnegie Institution for Science in Baltimore and Tom Maniatis of Columbia University for "exceptional leadership and citizenship in biomedical science." Besides making key discoveries in genetics, both men have worked to help research by others. Maniatis co-wrote a manual on lab techniques, first published in 1982, that became widely used. Brown founded an organization that awards fellowships to young investigators and built an impressive biology research program at the Carnegie institution, the foundation said.

The Lasker foundation was established in 1942. Albert Lasker was an advertising executive who died in 1952. His wife, Mary, was a longtime champion of medical research before her death in 1994.

Canadians James Till and Ernest McCulloch received the 2005 Lasker award for Basic Medical Research for their work on stem cells. The pair were pioneers in the field and have been called the "fathers of stem cell science."