434 VITAMIN K GROUP 



boplastin diminishes in the vitamin K deficiency of obstructive jaundice 

 and returns to normal under the influence of vitamin K therapy."^ Certain 

 characteristics of cothromboplastin are its presence in normal plasma or 

 serum and even in aged plasma [thus clearly differentiating it from both 

 prothrombin and Ac-globulin (factor V or labile factor)]. 



During the interval when the "prothrombin time" of the newborn is 

 prolonged, a prothrombin conversion factor was found lacking by Randall 

 and Randall;"^ this factor is present in normal plasma, aged plasma, and 

 serum. 



Among the clotting changes resulting from dicoumarol therapy is a 

 diminution of stable prothrombin conversion factor i^^o ^j^jg precedes the 

 drop in prothrombin. The" stable factor — so named to distinguish it from 

 the labile factor of Quick — is present in normal plasma, prothrombin-poor 

 serum, and aged plasma. Cothromboplastin, in these and other respects, 

 appears to be identical with the stable factor. Both resemble, at least 

 superficially, the factor of Randall and Randall. 



Dam and coworkers^'^ have given their support to the opinion that there 

 are non-prothrombic clotting changes in both simple vitamin K deficiency 

 and dicoumarolization ; however, they suggest that a "delta" factor is 

 lacking in the former, but a different ("kappa") factor is reduced in the 

 latter (delta present in dicoumarol plasma and kappa in vitamin K-deficient 

 plasma) . That a difference exists between dicoumarol plasma and plasma of 

 simple vitamin K deficiency has been both confirmed'^ia g^j-^^j denied. '-^^ 



It becomes increasingly clear that the "hypoprothrombinemia" of the 

 newborn infant, of obstructive jaundice, and of dicoumarol therapy in- 

 volves, in addition to lowered prothrombin, one or more non-prothrombic 

 factors. ^22 Since vitamin K overcomes the coagulation defect in all three 

 conditions, one is inclined to recall the statement of Boyd and Warner i^^s 



"8 F. D. Mann, E. S. Shonyo, and F. C. Mann, Am. /. Physiol. 164, 111 (1951). 



119 A. Randall, IV, and J. P. Randall, Proc. Soc. Exptl. Biol. Med. 70, 215 (1949). 



120 C. A. Owen, Jr., and J. L. Bollman, Proc. Soc. Exptl. Biol. Med. 67, 367 (1948); 

 C. A. Owen, Jr., T. B. Magath, and J. L. Bollman, Am. J. Physiol. 166, 1 (1951). 



121 H. Dam, Nature 161, 1010 (1948) ; H. Dam and E. S0ndergaard, Biochim.et Biophys. 

 Acta 2, 409 (1948); 0. S0rbye, I. Kruse, and H. Dam, Acta Chem. Scand. 4, 549, 

 831 (1950); Anonymous, Nutrition Revs. 9, 36 (1951). 



i2ia M. Verstraete and R. Verwilghen, Acta din. belg. 6, 269 (1951). 

 12"^ A. J. Quick, C. V. Hussey, and G. E. Collentine, Proc. Soc. Exptl. Biol. Med. 79, 

 131 (1952). 



122 See also: F. Koller, A. Loeliger, and F. Duckert, Acta Haematol. 6, 1 (1951) ; R. F. 

 Jacox and R. F. Bays, Blood 5, 313 (1950) ; R. L. MacMillan. Science [N. S.] 108, 416 

 (1948); P. A. Owren, Rev. hematol. 6, 135 (1951); C. A. Mawson, /. Lab. Clin. Med. 

 34, Part 1, 458 (1949); H. E. Schultze, Arch, exptl. Pathol. Pharmakol. 207, 173 

 (1949); G. Y. Shinowara and W. B. Smith, Am. J. Clin. Pathol. 20, 341 (1950); L. 

 A. Sternberger, Blood 4, 1131 (1949). 



123 E. J. Boyd and E. D. Warner, /. Lab. Clin. Med. 33, 1431 (1948). 



