MacFormat 1996 July/macformat-039.iso/DATABASE/BODY/CU8.TXT

Text File | 1996-03-11 | 10.2 KB | 213 lines | [TEXT/????]

1.5
Thousands of diabetics owe their lives to Banting, a largely
self-trained scientist. Before insulin treatment became
available, diabetes killed the young and shortened the life of
the elderly. The existence of insulin and its origin in the
pancreas (which also produces digestive ferments) was
deduced more than 20 years before, but all attempts to
isolate it had failed. Banting had a patient in whom disease
had destroyed the digestive part of the gland, yet diabetes
did not follow. This suggested that previous attempts to
extract insulin had failed because, in the process, digestive
ferments had destroyed the insulin. His experiments showed
this to be correct, and from his findings other scientists
devised the modern process which extracts insulin in large
quantities. Banting's ability to see the point others had
overlooked was characteristic
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2.2
The insulin treatment for diabetes was the result of
experiments in which Banting worked in collaboration with
the late Dr. J.R. Macleod and Dr. C.H. Best.  Banting began his
research on the internal secretion of the pancreas at Toronto
University on May 16, 1921, and the new treatment was
described in The Times on November 17, 1922.  The
discovery was no sudden or accidental revelation.  It had
been known during many years that the so-called island
tissue of the pancreas exerted a profound influence on the
sugar content of the blood, and, further, that in cases of
diabetes the island tissue was usually in a state of weakness
or degeneration.

Many attempts had been made to supply pancreatic extracts
to diabetic patients, but these attempts failed because, as is
now recognized, the island tissue had not been obtained in a
condition of enough potency to exert its influence.  Banting's
success was due to the method he adopted whereby island
tissue was made available in such potency as to effect the
necessary control of the sugar content of the blood.  Insulin
is, in fact, an extract of island tissue in as pure a state as can
be obtained, that is to say, as completely free as possible
from other elements present in the pancreas.

It represents, therefore, the coping-stone of an arch built in
long years by many hundreds of workers, each of whom
contributed his quota of knowledge.  It has proved to be one
of the most important medical discoveries, for by the use of
insulin many lives have been saved and many others
prolonged, while much disability has been prevented.

Frederick Grant Banting was born at Alliston, Ontario on
November 4 1891, and was educated at Alliston High School
and at Toronto University.  Before his career had really
begun the last War broke out, and joining up he served in
Canada, England, and France during the years 1915 to 1919.
He saw a good deal of fighting, was wounded in the arm at
Cambrai, and for his gallantry was awarded the M. C.  Later
he was invalided to England suffering with blood poisoning.
Before he left England he became M. R. C. S and he returned
to Canada in 1919 to become resident surgeon at the Hospital
for Sick Children, Toronto.  The next year he left the hospital
to take up private practice at London, Ontario, at the same
time undertaking the work of a part-time assistant in
physiology at the Western University in the town.  The
turning point in his career came in May, 1921, when he
returned to Toronto University to commence his research on
the internal secretion of the pancreas.  He combined with his
research work the lectureship in pharmacology in the
university from 1921 to 1922, and after that was senior
demonstrator, Department of Medicine until he was
appointed in 1923 Professor of Medical Research, which Chair
he held until his death.

Many honours came to him.  He was awarded the Starr Gold
Medal for the doctorate, University of Toronto, in 1922; the
Nobel Prize for Medicine (with DR.  J.  R.  Macleod) in 1923;
the Scott Medal in 1924; the Fellowship of the Royal Society
of Canada in 1926; the Cameron Prize (Edinburgh) in 1927;
the Flavelle Medal of the Royal Society of Canada in 1931; the
Apothecaries' Medal (London) in 1934; and the F. N. G. Starr
Gold Medal (Canadian Medical Association) in 1936, and the
Royal College of Surgeons made him an honorary Fellow in
1930; he was elected a Fellow of the Royal Society in 1935;
and the Royal College of Physicians made him an honorary in
1936.  He became D. Sc. (Toronto), 1923 LL. D.  (Queen's),
1923; Sc. D.  (Yale).  1924; LL. D.  (University of Western
Ontario), 1924; and D. Sc. (McGill), 1936.  In 1934 he was
created K. B. E.

It was not until 1925 that Banting went to Stockholm to
receive the Nobel Prize, and when he went he was asked to
deliver the Nobel Lecture, the first Canadian to be so
honoured.  Banting always felt that an injustice had been
done to Dr.  Best because he had not also been recognized by
the Nobel Prize committee, and he therefore shared with Dr.
Best his half of the Nobel Prize.  Banting was naturally
anxious that his work should be carried on, and for that
purpose he established a medical research foundation, which
was later to be known by his name.  Patients who had
derived benefit from the insulin treatment were among the
most generous donors to the fund and their gifts totalled
nearly $4, 500.  Medical care of the Eskimo was another
project in which Banting took great interest.  He went to the
Arctic to see if it were possible to set up hospital for the
treatment of the Eskimo, but it was found that no suitable
scheme could be formulated owing to the wandering life led
by those people.  While in the Arctic Banting painted a
number of pictures which evoked favourable comment, for
he was a talented artist.
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2.3
The fifteen-year-old daughter of Mr. Hughes, the United
States Secretary of State, is in hospital in Toronto undergoing
treatment for diabetes by Dr.  F.G. Banting, who is the
originator of the insulin treatment.

For over a year Dr.  Banting, with several associates, has been
engaged in research work in connexion with diabetes.  It is
apparently agreed among leading physicians in Canada and
the United States that the treatment has already prolonged
the lives of many sufferers and been effectual as a
preventive in many cases.  The remedy is being
manufactured at the Connaught Laboratory, Toronto, and at
Indianapolis, under the direction of the Medical Faculty of
the University of Toronto.  It is understood that in Great
Britain it is under the control of the Royal College of
Physicians and the Royal College of Surgeons.

It has long been known that removal of the pancreas, an
abdominal gland, causes diabetes.  Yet extracts of this gland
failed to relieve it.  Later work showed that the pancreas has
a double function.  It casts into the bowel ferments which
maintain digestion; but it also casts into the blood stream,
directly, an "internal secretion. "  It is this latter which is the
important factor in connexion with diabetes.

Banting and his co-workers conceived the idea of closing up
in an animal the tube connecting the pancreas with the bowel
and so causing the gland to lose one of its functions and
augment the other.  Preparations of this one-function gland
were subsequently used and injected into diabetic dogs,
which there-upon rapidly improved.  The product thus
obtained is termed "insulin, " because it is derived from the
"island tissue" of the pancreas.

Attempts were made later to use the preparation in cases of
human diabetes, and the Lancet reports that an improvement
has been noted.  The extract is given directly into a vein.
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2.5
Limited testing of insulin produced by genetic engineering, or
the procedure known as recombinant DNA, is in progress at
Guy's Hospital, London.  It is the first use in people of a
medicinal preparation made by genetic manipulation.

The tests on healthy volunteers to check the quality of the
insulin, are being made with a limited amount of this novel
source of human insulin obtained from laboratory-scale
production.

But the company involved in the manufacturing, Eli Lilley, is
building plants at Speke, near Liverpool, and at Indianapolis,
in the United States, costing a total of $18m for commercial
operation.  The first batches needed for clinical trials should
be ready from Speke in a few months.

Although the new substance is called human insulin because
it is identical in biological and chemical characteristics with
that generated by the human pancreas, the compound is
synthesized by making the type of genes that control the
production of insulin in the laboratory.

These man-made genes are then spliced by biochemical
methods into specially selected strains of bacteria, which
then synthesize insulin.

Professor Harry Keen, professor of human metabolism at
Guy's Hospital, described the advantages of this biosynthetic
insulin yesterday, when outlining plans for clinical trials to
be approved by the Committee on the Safety of Medicines.

The new method offers a more convenient source than the
traditional one of processing large quantities of animal tissue
to obtain bovine or porcine insulin.

As those preparations are not identical with that produced
by the body, the human insulin may provide the diabetic
with a better control over regulating the sugar level in the
blood.

Professor Keen hopes that will reduce some of the side-
effects among older long-term diabetics.  He said blindness
due to long-term complications was the largest cause of loss
of sight among the registered blind in industrial countries.

The first tests have been a comparison of the established
purified animal type of insulin with the biosynthetic variety.

The Eli Lilly company developed the first commercial
production of insulin from animal pancreas glands in 1923,
but forecasts of long range supplies of animal tissue suggest
that a shortage of supplies is likely in about 20 years.

The method of making the hormone is a more complicated
procedure because human insulin consists of two chains of
molecules, lying side-by-side and linked in a very specific
way.

In the biosynthesis, one microorganism is instructed to make
chain A and another to create chain B.  After the material is
extracted and purified, the two chains are carefully paired-
up to make the human type.