January 23,
1922. That date marked the end of the death sentence for people
suffering from diabetes mellitus. After nine months of effort at the
University of Toronto in Canada, Dr. F.G. Banting and student C.H. Best
gave birth to a new era in the treatment of diabetes mellitus. They
successfully treated a human diabetic with insulin. While the discovery
of insulin was one of the greatest medical achievements of this century,
the Flame of Hope literally still burns at Sir Frederick G. Banting
Square at the Banting Museum in London, Ontario. When a cure, rather
than a treatment, for diabetes mellitus is found, the flame will be
extinguished
The objectives
of insulin therapy are:
Maintain blood
glucose concentrations as close to normal as possible;
Prevention of
insulin "under dose" or carbohydrate overdose, leading to
life-threatening diabetic (hyperglycemic) coma; Warning signs of
hyperglycemia include drowsiness, flushed face, thirst, appetite loss,
fruity (ketone) breath odor, glucose and acetone (ketones) in urine,
nausea, vomiting, dehydration.
Prevention of
short-term episodes of hyperglycemia;
Prevention of
long-term complications of diabetes, such as blindness, heart attack,
and kidney failure;
Prevention of
insulin overdose, leading to life-threatening hypoglycemic coma. Warning
signs of hypoglycemia include very rapid heart rate, tremor, pale skin,
and profuse sweating. Administration of glucose or rapidly absorbed
carbohydrate reverses these signs and prevents hypoglycemic coma.
Insulin
preparations are obtained either from the pancreas of animals (pigs -
porcine; cows - bovine) killed for meat or, more commonly, insulin is
made in laboratories by bacteria that have the genes to make the
"human" form of insulin. Human insulin does not come from
humans, but it is identical to the naturally-occurring insulin in
humans. Animal insulin is almost, but not quite, identical to human
insulin, but there is a higher incidence of allergic reactions to animal
insulin. Insulin is usually injected under the skin (subcutaneously),
and occasionally into a muscle (intramuscularly). In an emergency,
regular insulin may be injected intravenously. Besides differing in
their source, insulin preparations also differ, very importantly, in the
time required to have an effect (onset of action), the time to peak
effect, and the length of time the insulin remains working (duration of
the effect). Combinations of different insulin are also available, and
some patients prefer to mix their own. The properties of different
insulin preparations are summarized in the table below. The source
(bovine, porcine, or human) is omitted for brevity.
