開始內容
裝飾
簡悅威

第130屆 

學位頒授典禮

 (1987)

簡悅威

名譽科學博士

Mr Chancellor, if you visit the island of Cos, in the Aegean sea, you may be taken to a great tree under which the physician Hippocrates is said to have taught his students some 2,500 years ago. With due modern scepticism, we may doubt whether it really is the same tree.

Hippocrates, or the Hippocratic author, wrote the following words:

"No-one can know anything about the diseases we are discussing simply by using their eyes. This is why I call them 'hidden diseases', though this does not mean that medical science cannot deal with them...They can be overcome so far as the constitution of the sick makes it possible to investigate them, and so far as the capacities of future researchers are well-fitted to the task."

Before you today, Mr Chancellor, is just one of those successors for whom Hippocrates hoped: a man well-fitted to the task of researching into "hidden diseases", and applying his fundamental discoveries to the treatment of the sick.

One such disease is today prevalent in the land of Hippocrates, as well as in Italy, and that is thalassaemia. Indeed, though first known as Mediterranean anaemia, this disease, with sickle-cell anaemia, is now known as the most common genetic disease in the world.

The unborn foetus, Mr Chancellor, does not breathe, but takes its oxygen from its mother. Its red blood cells are therefore different from those of an adult. They cling to oxygen more tenaciously. But when we are born, a sort of genetic switch tells our bone marrow to start producing adult haemoglobin. Within some months of birth, the foetal blood cells are normally replaced by the adult variety.

Unfortunately, Mr Chancellor, some of us are genetically so made that the adult haemoglobin then produced is defective. It is inefficient in carrying oxygen round the body. This is a variable defect. In the worst cases, a baby will die as soon as its foetal blood cells have died out.

It was Kan Yuet Wai who pioneered our understanding of the nature and causes of this condition. He was first drawn to study it when, as a Research Fellow in haematology at McGill University in the mid 1960s, he was asked to see an infant with hydrops foetalis.

His first step was to study the different forms of thalassaemia by investigating the globin chains in the blood; he then studied the synthesis of globin in the foetus, studies which opened the possibility of diagnosis of the unborn. In due course, Dr Kan carried out the first successful prenatal diagnosis for a haemoglobin disorder by the analysis of foetal blood, a result published in 1975.

At the same time, Dr Kan was studying the genetic basis of the condition, using a new technology based on the then recent discovery of reverse transcriptase. In 1974, he was able to publish in Nature the first demonstration for any disease that it was caused by the deletion of a gene from the chromosome. This fundamental discovery made it possible to effect prenatal diagnosis no longer by obtaining foetal blood, but by the safer method of direct analysis of the deoxyribonucleic acid in the amniotic fluid.

Dr Kan became internationally famous for this work. It is not only of the first scientific importance, but also has very significant clinical applications. Not only can the doctor now determine whether an unborn baby has thalassaemia, and - if so - in what form, but there is also the prospect of genetic manipulation which, by preventing the thalassaemic baby from switching to the production of defective haemoglobin, might allow it to develop normally using the foetal variety. Dr Kan is also actively involved in this taxing research.

Dr Kan has carried out related work on sickle-cell anaemia, and other researchers have followed his pioneering lead, and are developing methods of prenatal diagnosis of other genetically determined diseases, especially those associated with defective mental and physical development.

Mr Chancellor, Kan Yuet Wai was born in 1936, the youngest of fourteen children. It was his father Kan Tong Po, a founder of the Bank of East Asia, who said to him: "You are going to be a doctor!" He duly took a distinguished MBBS at the University of Hong Kong in 1958. After appointments at various North American universities, he went to the University of California at San Francisco as Associate Professor, and also took the post of Chief of the Haematology Service at San Francisco General Hospital. In 1977, he became a full Professor of Medicine, and in 1979 was additionally appointed Professor of Biochemistry and Biophysics. From 1976 he was Investigator at the Howard Hughes Medical Institute Laboratory for the study of human genetic diseases, of which he is now Director, and in 1983 became the Louis K Diamond Professor of Haematology at the University of California at San Francisco.

His father had assumed early on that with his strong clinical background he would move into the rich pastures of private practice in Hong Kong. Instead he made a brilliant teaching and research career, and has become one of today's leading medical scientists. This has been recognised, Mr Chancellor, by many honours, far too many for me to list for you today. But they include his honorary degree in 1981 from the University of Cagliari in Sardinia (where he had collaborated with doctors treating a population showing a high incidence of thalassaemia); his election as Fellow of the Royal Society in 1981 (an honour rarely accorded to anyone outside Britain); the award in 1984 of the Lita Annenberg Hazen award for excellence in clinical research, which is given to a physician whose "investigative studies have changed the medical profession's perception and treatment of disease"; and his election last year to the United States National Academy of Sciences.

In this career, Dr Kan has been able to combine fundamental scientific research with clinical applications. Mr Chancellor, this is a rare and important talent. In medicine, as in other disciplines, increasing specialisation has tended to create undesirable gulfs between specialties. Dr Kan is one of the few doctors in modern times who is known and respected for his ability to bridge this difficult gap.

Mr Chancellor, as a young man, Dr Kan was fond of watching horror movies; yet the stereotyped fancies about the scientist who by tampering with life unlocks the powers of evil, fancies which have haunted our imagination since Mary Shelley wrote the story of Frankenstein, are the very opposite of the researcher whose discoveries are a power for good. What Dr Kan has discovered about "hidden diseases" could never have been dreamt of either by Mary Shelley, or by the pupils of Hippocrates sitting under that tree on the Island of Cos.

Mr Chancellor, for his contribution to medical science and medical education, I present to you Kan Yuet Wai, Doctor of Medicine, Doctor of Science, Fellow of the Royal Society, member of the National Academy of Sciences, brilliant alumnus of the University of Hong Kong and distinguished scion of a well-known Hong Kong family, clinical physician and investigator of the hidden secrets of disease, bridger of the gap between theory and practice, youthful lover of horror films but worthy inheritor of the oldest and best traditions from that tree of medical science, for the award of the degree of Doctor of Science honoris causa.

Citation written and delivered by Professor Francis Charles Timothy Moore, the Public Orator.

裝飾