In 1939, McKee and Doisy and their co-workers1 showed that vitamin K has a quinoid structure. This led to investigation of the antihemorrhagic value in cases of experimental hypoprothrombinemia of many of the quinones. Of those examined, the 2-methyl-1,4-naphtho-quinone and the 2-methyl-3-hydroxy-1,4-naphthoquinone possessed the greatest antihemorrhagic activity.2 Rhoads and Fliegelman3 have recently reported favorable results in the control of hypoprothrombinemia in the human patient by the use of 2-methyl-1,4-naphtho-quinone. Binkley, Doisy and others4 and Feiser5 have recently shown that 2-methyl-3-phytyl-1,4-naphthoquinone and the natural vitamin K possess identical physical properties and the same empiric formula.
PRESENTATION OF DATA
In this paper are presented 10 cases of clinical hypoprothrombinemia of various causes and the responses of the patients to administration of 2-methyl-1,4-naphthoquinone. These cases are summarized in the accompanying table. Daily studies of the plasma prothrombin were made for each patient while he was receiving the drug.