A series of experiments performed from the late 1800s to the early 1900s revealed that diabetes is caused by the absence of a substance normally produced by the pancreas. In 1869, Oskar Minkowski and Joseph von Mering found that diabetes could be induced in dogs by surgical removal of the pancreas. In 1921, Canadian professor Frederick Banting and his student Charles Best repeated this study, and found that injections of pancreatic extract reversed the symptoms produced by pancreas removal. Soon, the extract was demonstrated to work in people, but development of insulin therapy as a routine medical procedure was delayed by difficulties in producing the material in sufficient quantity and with reproducible purity. The researchers sought assistance from industrial collaborators at Eli Lilly and Co. based on the company's experience with large scale purification of biological materials. Chemist George Walden of Eli Lilly and Company found that careful adjustment of the pH of the extract allowed a relatively pure grade of insulin to be produced. Under pressure from Toronto University and a potential patent challenge by academic scientists who had independently developed a similar purification method, an agreement was reached for non-exclusive production of insulin by multiple companies. Prior to the discovery and widespread availability of insulin therapy the life expectancy of diabetics was only a few months. COUNT 10
QSN1 What is diabetes caused from? ANS1 absence of a substance normally produced by the pancreas QSN2 Why was insulin therapy delayed? ANS2 difficulties in producing the material in sufficient quantity and with reproducible purity QSN3 How can diabetes be induced in dogs? ANS3 surgical removal of the pancreas QSN4 Before insulin, what was the life expectancy of diabetics? ANS4 only a few months QSN5 Who discovered that pancreatic extract reversed symptoms of pancreas removal? ANS5 Frederick Banting and his student Charles Best QSN6 Diabetes is caused by the removal of what organ? ANS6 pancreas QSN7 Left untreated, how long were diabetic patients were expected to live? ANS7 a few months QSN8 What could be adjusted in a sample of pancreatic extract to produce purer insulin? ANS8 pH QSN9 To purify insulin, Banting and Best sought the assistance of what company? ANS9 Eli Lilly and Co. QSN10 Minkowski and von Mering did surgical tests on what animal? ANS10 dogs