The role of vitamin K in the synthesis of prothrombin has been examined with the following results. 1. Vitamin K deficiency has no effect on general protein synthesis as studied by amino acid incorporation into protein in vivo and in vitro and by tryptophan pyrrolase production following tryptophan feeding. 2. Prothrombin activity was found in normal rat liver microsomes with increased release ...

AIM To determine whether vitamin K1, which is routinely administered to neonates, could act as an exogenous oxidising agent and be partly responsible for haemolysis in glucose-6-phosphat-dehydrogenase (G-6-PD). METHODS G-6-PD deficient (n = 7) and control (n = 10) umbilical cord blood red blood cells were incubated in vitro with a vitamin K1 preparation (Konakion). Two concentrations of Vitam...

Previous studies have demonstrated that supplemental alpha-tocopherol inhibited calcium-induced cytosolic enzyme efflux from normal rat skeletal muscles incubated in vitro and suggested that the protective action was mediated by the phytyl chain of alpha-tocopherol [1]. In order to investigate this further a number of hydrocarbon chain analogues of tocopherol (7,8-dimethyl tocol, 5,7-dimethyl t...

Vitamin K deficiency bleeding (VKDB) due to physiologically low vitamin K plasma concentrations is a serious risk for newborn and young infants and can be largely prevented by adequate vitamin K supplementation. The aim of this position paper is to define the condition, describe the prevalence, discuss current prophylaxis practices and outcomes, and to provide recommendations for the prevention...

BACKGROUND Idiopathic vitamin K deficiency in infancy or acquired prothrombin complex deficiency (APCD) is a serious bleeding disorders in infants. It leads to a high mortality rate and permanent neurological sequele among the survivors. A low vitamin K intake by infants is suggested to have a major role in the pathogenesis. To reduce the incidence of this syndrome, its risk factors have to be ...

The vitamin K metabolism of three patients with factitious purpura due to brodifacoum ingestion was studied. These patients, who presented with bleeding disorders due to deficiency of the vitamin K-dependent blood clotting proteins, were refractory to vitamin K1 at standard doses and required fresh frozen plasma to control bleeding until large doses of vitamin K1 were used. Metabolic studies de...

Vitamin K is a nutrient that was originally identified as an essential factor for blood coagulation. Recently, vitamin K has emerged as a potential protector against osteoporosis, atherosclerosis, and hepatocarcinoma. Accumulated evidence indicates that subclinical non-hemostatic vitamin K deficiency in extrahepatic tissues, particularly in bone and possibly in vasculature, exists widely in the...

in this study the plasma levels of lipid peroxidation (lp) products, protein carbonyls and antioxidant capacity of plasma as judged by ferric reducing ability of plasma (frap assay) were compared in adult and weanling rats treated with vitamin k1 phylloquinone).

Intact male and female albino rats fed a vitamin K-deficient diet develop a plasma prothrombin-proconvertin deficiency. Male rats respond with a precipitous drop to approximately 20-30% of normal plasma levels within 2-5 days, whereas female rats respond at a slower rate. Ethynylestradiol, 5-10 mug/day, or castration, reduces the progressive decline of plasma prothrombin-proconvertin seen in no...