My mentor and friend Stephen Semple, who has died aged 92, was professor of medicine successively at the London medical schools of St Thomas’, the Middlesex and University College, and devoted his career to applying scientific methods to clinical medicine.
While on a two-year posting to Philadelphia in 1957-59, he began research on the control of breathing. I first met him just after his return.
Back in London he decided to take a new approach to his research and study the cause of the increase in breathing on exercise, which was then unknown. The physiologist William Yamamoto had postulated that the missing signal might derive from the cyclical nature of breathing producing an oscillating signal in blood carbon dioxide and hence arterial blood pH (acidity). No measurement techniques were available at the time to detect such a signal.
Steve recruited Dr David Band and together they developed a fast responding pH electrode that could be used to measure such changes. In a series of papers published from 1966 onwards, Steve showed that such oscillations existed, that they were detected by the arterial respiratory chemoreceptors, and that they could be the link relating the increased metabolism of exercise to the increase in breathing. This was new territory and marked a significant contribution to the understanding of respiratory control.
Born in London, Steve was the elder child of John Semple, chairman of a family firm in the City, Semple & Co, and his wife, Janet (nee Casson). He was educated at Westminster school and St Thomas’, qualifying in 1950. He did national service in Malaya in 1953-55. While in Philadelphia he met Penny Aldington, the daughter of a British diplomat, and they married in 1961.
His career prospered at St Thomas’, leading to a personal chair in 1969. The following year he was appointed professor of medicine at the Middlesex, where for the next 18 years he continued his research, contributing to new areas in respiratory medicine, such as lung problems in patients with Aids/HIV and disorders of breathing in sleep.
In 1985, the mergers in London medical schools found him professor of medicine and head of department at the merged UCH and Middlesex school. He retired in 1991, but continued research and teaching at Imperial College until the age of 86. In 2009 he was awarded the British Thoracic Society medal for his contribution to respiratory medicine and science.
Always a driven and dedicated clinician, he found time to indulge his love of music, playing the flute and pursuing his love of opera. An annual visit to Glyndebourne was sacred. A lifelong member of the Queen’s Club, in west London, he was a regular and enthusiastic tennis player – enthusiasm perhaps outstripping natural talent. A model and inspiration, he started many young doctors on rewarding careers in clinical medicine and research.
He is survived by Penny, their three sons, Edward, Robert and David, and four grandchildren.
