Disturbances of the coagulation of the blood may occur if the plasma prothrombin content is below 20 per cent. Such a reduction is presumed to occur under conditions which affect the supply, the absorption or the utilization of vitamin K. In the adult it is difficult to demonstrate an actual deficiency of vitamin K in the diet. The explanation given is that the bacterial flora of the intestine furnishes an intrinsic source of vitamin K which is sufficient to give an adequate supply even if the diet itself is deficient or lacking in the vitamin. In the newborn infant, however, there is a decrease in the plasma prothrombin level during the first three days of life, followed by a rise to normal values. Quick1 has suggested that this is due to a prompt establishment of bacterial flora in the intestine following the ingestion of food. Salomonsen and Nygaard2
SANFORD HN, SHMIGELSKY I. IS THE PRESENCE OF BILE AND FOOD IN THE SMALL INTESTINE NECESSARY FOR THE FORMATION OF PROTHROMBIN? STUDIES ON THREE INFANTS, ONE WITH CONGENITAL ABSENCE OF THE GALLBLADDER AND EXTRAHEPATIC DUCTS AND TWO WITH CONGENITAL ATRESIA OF THE ESOPHAGUS. Am J Dis Child. 1942;63(5):894–899. doi:10.1001/archpedi.1942.02010050058006
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