Jay McLean (1890 – November 14, 1957) was an American

surgeon In medicine, a surgeon is a medical doctor who performs surgery. Even though there are different traditions in different times and places, a modern surgeon is a licensed physician and received the same medical training as physicians before spec ...

. He is most notable for his major contribution to the discovery of

heparin Heparin, also known as unfractionated heparin (UFH), is a medication and naturally occurring glycosaminoglycan. Heparin is a blood anticoagulant that increases the activity of antithrombin. It is used in the treatment of myocardial infarction, ...

Early life

Born in

San Francisco San Francisco, officially the City and County of San Francisco, is a commercial, Financial District, San Francisco, financial, and Culture of San Francisco, cultural center of Northern California. With a population of 827,526 residents as of ...

in 1890, he was the son of a physician, John T. McLean. McLean's family lost their home and assets in the

1906 San Francisco earthquake At 05:12 AM Pacific Time Zone, Pacific Standard Time on Wednesday, April 18, 1906, the coast of Northern California was struck by a major earthquake with an estimated Moment magnitude scale, moment magnitude of 7.9 and a maximum Mercalli inte ...

. McLean set out to become a surgeon during his last year at Lowell High School. Following education at Lowell High School, he entered the

University of California at Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a public land-grant research university in Berkeley, California, United States. Founded in 1868 and named after the Anglo-Irish philosopher George Berkele ...

in 1909, obtaining his Bachelor of Science degree in 1914.

Career

McLean moved to

Baltimore Baltimore is the most populous city in the U.S. state of Maryland. With a population of 585,708 at the 2020 census and estimated at 568,271 in 2024, it is the 30th-most populous U.S. city. The Baltimore metropolitan area is the 20th-large ...

following his graduation from the

University of California The University of California (UC) is a public university, public Land-grant university, land-grant research university, research university system in the U.S. state of California. Headquartered in Oakland, California, Oakland, the system is co ...

before receiving an acceptance from

Johns Hopkins School of Medicine The Johns Hopkins University School of Medicine (JHUSOM) is the medical school of Johns Hopkins University, a private research university in Baltimore, Maryland. Established in 1893 following the construction of the Johns Hopkins Hospital, th ...

. Following his move he was informed of a vacancy at the school and began his medical studies in 1915. McLean entered

in 1915 where he met and began work with physiologist

William Henry Howell William Henry Howell (February 20, 1860 – February 6, 1945) was an American physiologist. He pioneered the use of heparin as a blood anti-coagulant. Early life William Henry Howell was born on February 20, 1860, in Baltimore, Maryland. He gra ...

. Howell admitted McLean into his laboratory and assigned him the task of investigating if an impurity was the cause of the pro-coagulating effect of cephalin or if cephalin itself had a naturally pro-coagulating effect and to compare it to other phosphatides. In 1916, when McLean was a second-year medical student, he was investigating pro-coagulant compounds when he first isolated a fat-soluble phosphatide anti-coagulant. This anti-coagulant was first isolated from the liver tissue of canines, which is how Heparin got its name(''hepar'' or "ήπαρ" is Greek for "liver"; ''hepar'' + '' -in''), first coined in 1918. Following the departure of McLean, Howell continued his work and with the assistance of T. Emmett Holt he isolated a water-soluble

polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with wat ...

anticoagulant. Howell also coined 'heparin' as the name of this compound despite being different from the compound previously discovered by McLean. McLean graduated from Johns Hopkins in 1919 and began an internship at the Johns Hopkins Hospital. Following completion of his internship, he began a surgical residency, in which he rotated through the Hunterian Laboratory, the laboratory founded by

Harvey Cushing Harvey Williams Cushing (April 8, 1869 – October 7, 1939) was an American neurosurgery, neurosurgeon, pathologist, writer, and draftsman. A pioneer of brain surgery, he was the first exclusive neurosurgeon and the first person to describe Cush ...

in 1904. McLean stayed in

until 1924 when returned to his alma-mater, the University of California to become an instructor in surgery. After three years in California, McLean took a position in the Department of Pathology at

Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...

, a position which he held until 1939. After leaving Cornell, McLean moved to

Columbus, Ohio Columbus (, ) is the List of capitals in the United States, capital and List of cities in Ohio, most populous city of the U.S. state of Ohio. With a 2020 United States census, 2020 census population of 905,748, it is the List of United States ...

, where he worked in private surgical practice and was appointed as an associate professor of surgery at Ohio State medical school. In 1949, he was appointed director of Radiation Therapy and Consultant in Malignant Diseases in

Savannah, Georgia Savannah ( ) is the oldest city in the U.S. state of Georgia (U.S. state), Georgia and the county seat of Chatham County, Georgia, Chatham County. Established in 1733 on the Savannah River, the city of Savannah became the Kingdom of Great Brita ...

, where he remained until his death in 1957, aged 67 years. 6 years after McLean passed away he was awarded a plaque by the Upjohn Company to Johns Hopkins School of Medicine for his work in the discovery of heparin as a second-year medical student.

References

{{DEFAULTSORT:McLean, Jay 1890 births 1957 deaths American surgeons Cornell University faculty Johns Hopkins University alumni Johns Hopkins University faculty 20th-century surgeons