Jay McLean
1890-1957 · American · biochemistry
American physician whose 1916 identification, as a second-year Johns Hopkins medical student in William Henry Howell's laboratory, of an anticoagulant principle subsequently named heparin established the second naturally-occurring anticoagulant principle of mammalian origin, parallel to Haycraft's earlier hirudin from medicinal leech.
Profile
- Life years
- 1890-1957
- Nationality
- American
- Era
- early 20th
- Primary field
- biochemistry
Institutional Affiliations
- University of California, Berkeley (B.S., 1913)
- Johns Hopkins University School of Medicine (M.D., 1919)
- Ohio State University (Surgical Faculty)
- University of California, San Francisco (Surgical Faculty)
Key Contributions
- Identified, as a second-year medical student at the Johns Hopkins University School of Medicine in 1916, an anticoagulant principle in canine hepatic and cardiac tissues subsequently characterized and named heparin by Howell (1918).
- Authored 'The Thromboplastic Action of Cephalin' (1916), the foundational paper from his work in Howell's laboratory, published in the American Journal of Physiology.
- Pursued a subsequent surgical and clinical career, including service as a surgeon at Ohio State University and later at the University of California, San Francisco, with continued interest in the clinical applications of anticoagulant therapy.
- Advocated, late in his career, for the formal recognition of his role in the 1916 identification of heparin, contributing to the historical-medical literature that distinguishes McLean's discovery of the activity from Howell's subsequent characterization and naming.
- Established, through his 1916 discovery in Howell's laboratory, the second naturally-occurring anticoagulant principle of biological origin, parallel to John Berry Haycraft's 1884 isolation of hirudin from the medicinal leech.
Importance to Hirudotherapy
Jay McLean's contribution to hirudotherapy is the parallel-historical role his 1916 discovery played in establishing the second naturally-occurring anticoagulant principle of biological origin, parallel to John Berry Haycraft's 1884 isolation of hirudin from the medicinal leech. Working as a second-year medical student in William Henry Howell's physiology laboratory at Johns Hopkins, McLean isolated from canine hepatic and cardiac tissues an anticoagulant activity that Howell subsequently characterized and named heparin in 1918. The McLean-Howell-heparin lineage and the Haycraft-hirudin lineage together established the two foundational naturally-occurring anticoagulant principles of modern pharmacology: one from a parasitic invertebrate, the other from mammalian connective tissue. The subsequent twentieth-century pharmaceutical development of these two lineages diverged for several decades. Heparin was rapidly developed into a clinically-used parenteral anticoagulant in the late 1930s and 1940s and became the dominant anticoagulant of mid- and late-twentieth-century clinical medicine. Hirudin, by contrast, remained primarily a research tool and a biochemical curiosity until the late-twentieth-century recombinant-DNA era, when the cloning of the hirudin gene enabled the development of lepirudin, desirudin, and ultimately the synthetic direct thrombin inhibitor bivalirudin. The two lineages have since converged in the modern anticoagulant-pharmacology field. The American Society of Hirudotherapy regards Jay McLean as the discoverer of the principal mammalian-origin parallel to the leech-derived hirudin tradition. The historical question of credit between McLean (who isolated the activity) and Howell (who characterized and named the substance) has been the subject of considerable medical-historical debate; ASH regards the historical record as supporting both McLean's role in the original observation and Howell's role in the subsequent characterization, in a manner closely paralleling the broader history of biomedical discovery in which student-investigator-supervisor credit allocations are frequently complex.
Key Publications
- The Thromboplastic Action of Cephalin · American Journal of Physiology (1916)
- The Discovery of Heparin · Circulation (posthumous; written 1940 and published posthumously) (1959)
External Resources
Influenced Research
Compounds and research areas tracing back to this figure's contributions:
Related Figures
John Berry Haycraft
1857-1922 · British (Scottish)
Edinburgh physiologist who discovered hirudin in 1884, founding the modern molecular pharmacology of leech saliva.
Karl Jacoby
1864-1926 · German
German pharmacologist who in 1902 produced the first crude hirudin powder, bridging Haycraft's discovery to industrial-scale anticoagulant chemistry.
Marie Termier
1859-1930 · French
French physician who in 1922 published one of the first formal clinical studies of leech therapy for post-surgical thrombosis, establishing modern clinical methodology in hirudotherapy.
Isabella P. Baskova
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