by Colin Green, professor emeritus University College London, colin.green@ucl.ac.uk

Cryobiologist Dr. David Pegg has died at 86. A pioneer in the field of low temperature biology, Pegg made perhaps his greatest contribution through research into the preservation of human kidneys, which he began in 1965.

He helped found the international Society for Cryobiology in 1964, and started its journal, Cryobiology, of which he later became editor in chief, eventually becoming the society’s president in 1974 and a Fellow in 2005.

In 1965 Pegg founded the British Society for Low Temperature Biology, which has now expanded to cover Europe; he twice served as its secretary.

Born in Chester, UK, Pegg attended King’s College London to study medicine. After graduating in 1956, he served in the school’s teaching group for a year, before working in its department of pathology for a decade from 1957, specializing in hematology.

In 1967, he left Westminster to join as a senior scientist the division of low temperature biology at the MRC’s clinical research laboratories in Mill Hill. Three years later he was promoted to head of cryobiology, the study of the effects of low temperatures on living things, at the MRC’s new clinical research center at Northwick Park hospital, Harrow, and remained there until attracted to Cambridge by Calne to become head of the MRC’s medical cryobiology group in 1978.

He stayed at MRC until 1992, when he set up the East Anglia Tissue Bank at the National Blood Service in Cambridge, serving as its director for a year. He was director of the medical cryobiology unit at York University from 1993 to 2006, and an honorary professor in the biology department from 1999 to 2018.

From dubious survival times of eight hours or fewer using simple surface cooling by surrounding the kidney in ice, Pegg and his colleagues at the Medical Research Council (MRC) in north London worked on techniques whereby a plastic tube was inserted into the renal artery and the organ was flushed with a cold solution of balanced salts and nutrients to cool it from within, a more efficient process.

Pegg developed sophisticated continuous perfusion methods, getting fluids to pass through a closed circuit that could be used to cool the kidney and even mimic blood to provide oxygen and essential nutrients. Both techniques are now used routinely in organ transplantation services worldwide allowing organs to be maintained for up to 30 hours and still function well after transplantation. Later, he pioneered new freezing techniques that have proved to be helpful in preserving plant cells for agriculture, reproductive cells for fish farming and, in the field of conservation, cells from endangered species of plants and animals.