Dame Julia Polak

Born: June 26, 1939; Died: August 11, 2014.

DAME Julia Polak, who has died aged 75, was one of the world's foremost experts in histochemistry, the branch of science that deals with the chemical composition of the body's cells and tissues. Ironically, having specialised in the tissue engineering of the lung, she began suffering from lung disease and heart failure herself, had a heart and lung transplant when she was 56 and became one of the world's longest transplant survivors.

She had initially been diagnosed with asthma. In medical terms, her condition turned out to be idiopathic pulmonary arterial hypertension. In laymans' terms, it was life-threatening. After her successful transplant, performed by a close colleague, Sir Magdi Yacoub, she went on to specialise in developing organs in her laboratory, using healthy cells to be used in transplants to replace unhealthy cells in the same patient. She spent much of the rest of her career trying to develop artificial lungs. Commenting on her own diseased lungs, she once said: "my lungs were not of any use. So I studied them."

In fact, her operation by Professor Yacoub was known as a domino transplant. He replaced her heart and lungs with those of a donor but her heart was strong enough to be transplanted to another patient.

Born in Argentina to a Jewish family who had fled persecution in Eastern Europe, she spent most of her career in the UK, notably in Hammersmith Hospital, later part of Imperial College London. It was for her breakthrough work there that she was made a DBE, Dame Commander of the Order of the British Empire, by the Queen in 2003.

That work included fundamental discoveries to help understand how the body's hormones and nerves interact, in the bladder, lung and heart and even in the brain. She recalled that when someone called her up claiming to be in Buckingham Palace and that she had been named a Dame, she hung up. "I thought it was a joke, someone looking for money," I thought. "When they called back, it took a while to sink in."

Her work as a histochemist is a little difficult for most of us to understand although it could prove vital to many of us. She pioneered a revolutionary technique known as immunohistochemistry, making peptides, or amino acid compounds, visible under a microscope, a technique now used around the world.

These peptides showed to her that human nerves "talk to each other." Her work became the inspiration for a well-received 2001 novel, Intensive Care, by Rosemary Friedman, about a woman professor who is diagnosed with the very lung disease she has long been researching and treating.

Julia Margaret Polak was born in Buenos Aires, in 1939, towards the end of what Argentines call the "Infamous Decade" of corruption and violence sparked by the Great Depression. Her father, Carlos Polak, was a lawyer and judge, her mother Rebecca Mactas Alpersohn a leading Jewish Argentine writer. Her younger brother became a well-known Argentinian lawyer. As a student at the University of Buenos Aires, she met Daniel Catovsky, who proposed while they were dancing the tango. They married in 1960 and moved to London in 1967 to do postgraduate studies, Julia as a pathologist.

She became Professor of Endocrine Pathology at Hammersmith Hospital, west London, where, with her charisma, she attracted a highly productive research team before her diagnosed "asthma" turned out to be far worse, possibly lethal.

It was then that she agreed to a heart and lung transplant by her friend and colleague, the Egyptian-born Sir Magdi Yacoub.

After the dangerous but successful operation, she decided to live life to the full, as a person and a scientist. Given her personal experience, she turned to researching tissue engineering and restoring normal lung function through engraftment of pluripotent stem calls. Big medical words that perhaps even her patients didn't understand. But she saved many lives. She went on to found the Tissue Engineering and Regenerative Medicine Centre at Imperial College London, based at Chelsea and Westminster hospital, and became its Professor and latterly Professor Emeritus.

In June 2011, Dame Julia's daughter Marina Catovsky, a 47-year-old London barrister known to her friends as Mina, was killed while crossing the road close to London Bridge by a motorcyclist who was exceeding the speed limit. Unbeknowns to her mother, Mina had joined the organ donor scheme.

Dame Julia never quite recovered from the tragedy but, as always, tried to turn it to good use. Mina's organs were used to save the lives of half a dozen people, including a baby. Julia and Mina became and remain quiet heroes in the lives of those families.

Dame Julia was a member of several advisory panels worldwide on tissue engineering and stem cells. She published close to 1,000 original papers wrote or edited several books, many of them seen as groundbreaking in medical science.

After the death of his colleague, and the lady into whom he transplanted a new heart and lungs, Sir Magdi Yacoub said: "During our short journey through Planet Earth, occasionally we have the great privilege of getting to know an exceptional individual such as Julia. We should be greatly appreciative of such a privilege."

Dame Julia is survived by her husband Daniel, a renowned expert on chronic adult leukemia, and their sons Sebastian and Michael.