BEYOND REASON
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Although there exists some debate over who discovered
pancreatic enzymes, it appears the French physician
Lucien Corvisart first described trypsin in 1856.
However, the German researcher Julius Kühne deserves credit
for actually naming this protease in 1876 and for introducing
the concept of digestive enzymes as catalysts secreted by the
pancreas that allow for efficient breakdown of food in the
gastrointestinal (GI) tract.
By 1900, the 3 main classes of pancreatic enzymes had
been identified: (1) the proteases that cleave proteins into
constituent amino acids and peptides; (2) the amylases that
reduce complex carbohydrates into simple disaccharides and
trisaccharides; and (3) the lipases, which convert triglycerides
into monoglycerides, diglycerides, and free fatty acids.
Physiologists at the time, aware these enzymes worked best in
a slightly alkaline environment, discovered that the pancreas
released these various ferments, as they were called, into the
duodenum during meals along with bicarbonate to neutralize
the acidic chyme arriving from the stomach.
By the late 1800s, there was a flurry of activity among
European researchers searching for therapeutic applications for
the newly discovered enzymes, above and beyond any purely
digestive use. Scientists discovered that trypsin could be useful in the treatment of diphtheria when applied directly to the
tough fibrous membrane formed in the throat that could, if
unchecked, lead to suffocation. In an animal model of the
disease, a preparation of trypsin applied in the larynx appeared
to digest away this tissue and when tested in humans, the
enzyme worked quite well. An early reference to the successful
treatment in humans dates from the October 23, 1886 issue of
the Journal of the American Medical Association.1
In response to these early successes, by 1900, 2
pharmaceutical firms, Merck and the New York–based
Fairchild, affiliated with Burroughs Wellcome, marketed
powdered trypsin preparations derived from animal sources
for treatment of the disease as well as injectable preparations for
a hoped-for systemic effect. In addition, preparations meant for
oral ingestion as a digestive aid became available, the most
widely prescribed known as Holadin.
In 1902, the English scientist John Beard, DSc (1858-1924),
Professor at the University of Edinburgh in Scotland, first
proposed an anticancer activity for trypsin. His thesis, which
would generate considerable controversy at the time,
represented the culmination of some 20 years of meticulous
research that began with the development of the nervous
system in invertebrates.
Beard was not a physician but a zoologist trained as an
embryologist: His graduate studies at the University of
Freiburg in Germany, from which he received his doctoral
degree in 1884, dealt with the embryogenesis of the sense
organs in an obscure worm.2
As his career evolved, he
focused his attention on the developing nervous system of
fish, then eventually mammals, and many of his pioneering
findings from this period in his life, now proven correct, are
standard fare in contemporary embryology texts.
It was Beard’s study of the embryonic nervous system
that, through a most convoluted route, led him to consider
the formation and growth of the placenta, which anchors the
mammalian fetus to the uterus and serves as the point of
connection between the maternal blood vessels, providing
oxygen and essential nutrients, and the blood of the embryo
carrying the wastes of metabolism.
Beard was the first scientist to report that in many
respects the placenta in its early stages—known as the
trophoblast (from the Greek “to feed or nurture”)—looks and