The incidence of Alzheimer's disease (AD) increases with age and in carriers of the apolipoprotein E4 genotype. A relative deficiency of vitamin K, affecting the extrahepatic functions of the vitamin, is common in ageing men and women. The concentration of vitamin K is lower in the circulating blood of APOE4 carriers than in that of persons with other APOE genotypes. Evidence is accumulating th...

We examined the effect of vitamin K and vitamin D supplementation on calcium balance in young rats fed a normal or low calcium diet. Eighty female Sprague-Dawley rats, 6 wk of age, were randomized by the stratified weight method into eight groups with 10 rats in each group: 0.5% (normal) or 0.1% (low) calcium diet, 0.5% or 0.1% calcium diet+vitamin K (vitamin K2, menatetrenone, 30 mg/100 g, foo...

All newborns require phylloquinone after birth to prevent vitamin K deficiency bleeding. Babies born prematurely may be at particular risk of deficiency without adequate supplementation during infancy. The main sources of phylloquinone in preterm babies during the neonatal period are the prophylactic dose of phylloquinone given at birth, and that derived from parenteral and/or enteral feeding. ...

The contents of vitamin K in the plasma and tissues (kidney, liver and gonad) of mummichog Fundulus heteroclitus fed diets supplemented with different vitamin K groups were determined. The vitamin K mainly detected in the gastrointestinal tract of each experimental group was the one supplemented in the respective diet, and all other forms of vitamin K were observed at low concentrations. This i...

There is strong evidence supporting the importance of vitamin K in bone health and the aetiological role of vitamin K deficiency in osteoporosis. In view of the common occurrence of osteoporosis among older subjects in Hong Kong, we have studied the dietary vitamin K intakes in 100 residents of a nursing home (43 men, 57 women; median age 81.0 years) and 88 free-living subjects attending a day ...

We describe a cell-based assay for studying vitamin K-cycle enzymes. A reporter protein consisting of the gla domain of factor IX (amino acids 1-46) and residues 47-420 of protein C was stably expressed in HEK293 and AV12 cells. Both cell lines secrete carboxylated reporter when fed vitamin K or vitamin K epoxide (KO). However, neither cell line carboxylated the reporter when fed KO in the pres...

Protein-bound gamma-carboxyglutamate (Gla) has been demonstrated in calcified atherosclerotic plaques. Vitamin K is required for the formation of Gla-residues. As the biological activity of Gla-proteins appears to be strictly dependent on the presence of the Gla-residues, vitamin K status may be an important factor in the development and progression of atherosclerotic calcifications. We studied...

BACKGROUND In many developing countries vitamin K prophylaxis is not routinely administered at birth. There are insufficient data to assess the cost effectiveness of its implementation in such countries. OBJECTIVE To estimate the burden of intracranial haemorrhage caused by late onset vitamin K deficiency bleeding in Hanoi, Vietnam. METHODS Cases of intracranial haemorrhage in infants aged ...

Vitamins D and K are lipid-phase nutrients that are pleiotropic - endowed with versatile homeostatic capacities at the organ, tissue, and cellular levels. Their metabolic and physiologic roles overlap considerably, as evidenced in the bone and cardiovascular systems. Vitamin D₃ (cholecalciferol, D₃) is the prehormone for the vitamin D endocrine system. Vitamin D₃ undergoes initial enzymatic con...

Vitamin K is a cofactor in the -glutamyl carboxylation pathway, a posttranslational conversion of specific glutamate residues into -carboxyglutamic acid (Gla) residues, catalyzed by the endoplasmic reticulum enzyme -glutamyl carboxylase. The substrates of carboxylase are the so-called vitamin K–dependent proteins, which are involved in diverse physiological processes such as blood coagulation, ...