Prevention of early vitamin K deficiency bleeding (VKDB) of the newborn, with onset at birth to 2 weeks of age (formerly known as classic hemorrhagic disease of the newborn), by oral or parenteral administration of vitamin K is accepted practice. In contrast, late VKDB, with onset from 2 to 12 weeks of age, is most effectively prevented by parenteral administration of vitamin K. Earlier concern...

The mechanisms by which vitamin E interferes with vitamin K activity, especially blood clotting, are not known, but hypothetically this interference may involve metabolic pathways. Phylloquinone (K(1)) must be converted to menaquinone (MK-4, the most potent extrahepatic tissue vitamin K) by truncation of the K(1) side chain and replacement with geranylgeranyl. Possible mechanisms for the vitami...

Vitamin K functions as a cofactor during the posttranslational modification of proteins. The reaction in question is the carboxylation of glutamate (Glu) residues into y-carboxyglutamate (Gla) and it is depicted in Fig. 1. Because Glu is only a weak Ca2l chelator and Gla a much stronger one, the vitamin K-dependent step substantially increases the Ca2"-binding capacity ofa protein. The discover...

The present paper describes a system in vitro that has been developed to mimic vitamin K metabolism and vitamin K function in liver. In this system the two pathways that are known to participate in vitamin K reduction are active and the vitamin K-dependent carboxylase accepts a synthetic pentapeptide as substrate. With this system in vitro the effect of warfarin on both pathways was examined un...

BACKGROUND AND OBJECTIVES Based on a high incidence of Vitamin K deficiency bleeding (VKDB) in breastfed infants with thus far unrecognized cholestasis, such as biliary atresia (BA), the Dutch regimen to prevent VKDB in breastfed infants was changed from a daily oral dosage of 25 µg to 150 µg vitamin K. Infants continued to receive 1 mg of vitamin K orally at birth. We compared the efficacy of ...

BACKGROUND AND OBJECTIVES Vitamin K, vitamin K-dependent proteins, and vitamin D may be involved in the regulation of calcification in chronic kidney disease (CKD). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Vitamin K and D status was measured as dietary intake, plasma phylloquinone, serum percent uncarboxylated osteocalcin (%ucOC), proteins induced by vitamin K absence (PIVKA-II), Vitamin...

Intramuscular administration of vitamin K for prophylaxis against hemorrhagic disease of the newborn has the disadvantage of increased cost, pain, anxiety to parents and risk of transmission of infection. Oral route is a better alternative. Oral absorption of vitamin K has been shown to be equally good using special oral preparations. However, this preparation is not available in India. A prosp...

The systematic use of antivitamin K anticoagulants (AVK) as rodenticides caused the selection of rats resistant to AVKs. The resistance is mainly associated to genetic polymorphisms in the Vkorc1 gene encoding the VKORC1 enzyme responsible for the reduction of vitamin K 2,3-epoxide to vitamin K. Five major mutations, which are responsible for AVK resistance, have been described. Possible explan...

REFERENCES 1. Nimptsch K, Rohrmann S, Kaaks R, Linseisen J. Dietary vitamin K intake in relation to cancer incidence and mortality: results from the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg). Am J Clin Nutr 2010;91: 1348–58. 2. Bolton-Smith C, Price RJ, Fenton ST, Harrington DJ, Shearer MJ. Compilation of a provisional UK database fo...

Montalembert et al report that PIVKA-II was detected in 33% of patients with cystic fibrosis, while vitamin K, plasma concentrations were normal.' It is astonishing that despite daily supplements of 5-10 mg vitamin K,, PIVKA-II was detectable in these patients. The authors conclude that PIVKAII is not associated with vitamin K deficiency, but with the use of antibiotics. There is some doubt as ...