Grabbing the golden ring  pg. 2

In the seventeenth century, English physician Thomas Willis added a urine taste test to the criteria for diagnosing diabetes. It wasn’t unusual for physicians to first suspect diabetes in men by noting the presence of crystals on their shoes. With the beginnings of modern chemistry in 1775, the source of the sweetness was identified as sugar, and by 1815 it was known to be glucose.

During these years, the only therapeutic advice was dietary. The nineteenth-century French physician Apollinaire Bouchardat, who required daily urine analysis of his patients, recognized that fasting reduced sugar levels and prescribed a spare diet. Observing that exercise increased carbohydrate tolerance, he admonished his patients, “You shall earn your bread by the sweat of your brow.”

Yet the real breakthrough in treatment was to come not from dietary prudence but from basic physiological studies of glucose metabolism that began in the latter half of the nineteenth century.

In 1869 a German pathologist, Paul Langerhans, discovered the existence of two systems of cells in the pancreas: the acinar cells, secreting the pancreatic juice into the digestive system, and islets floating between the acini, with some as yet unknown function. In 1889 Oscar Minkowski and Joseph Von Mering removed the pancreas from a dog and witnessed symptoms indistinguishable from diabetes.

The two German physiologists went on to eliminate acinar cell secretion as the culprit when, after tying off the ducts that feed digestive juices from the pancreas to the gut, diabetes did not develop. By the early twentieth century, a direct link had been made between diabetes and damage to the islet cells.

Failure piled upon failure as scientists from around the world went in search of the “internal secretion” responsible for diabetes. The gold ring was finally grabbed by a Canadian surgeon and a medical student in the summer of 1921. Dr. Frederick Banting and Charles H. Best, in collaboration with J.J.R. Macleod and J.B. Collip, successfully reversed diabetes in a depancreatised dog by injecting a concoction of pancreatic extracts, which the researchers later named “insulin.”

The discovery was front-page news around the world. Appeals from families of diabetic patients poured in, and after Banting and Best tested the extract on themselves and found it safe, the first insulin injection in a diabetic patient was given to 14-year-old Leonard Thompson in January 1922. Thompson, who had been surviving on the “starvation” diet, weighed less than 65 pounds and was near death. Insulin saved his life.

Since 1922, much has been done to better insulin therapy, both in terms of improved insulin preparations and ease of use. Purification of insulin reduced adverse reaction at the injection site, and modification of the insulin molecule has led to greater control over the duration of its effects, which translates to fewer injections.

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