Search results for "Vitamin K 1"
showing 10 items of 11 documents
Stabilization and detection of hydrophylloquinone as di-O-methyl derivative
2016
Phylloquinone is a redox active naphthoquinone involved in electron transport in plants. The function of this reduced form remains unclear due to its instability, which has precluded detection. Herein, a simple method that permits the stabilization of the reduced form of phylloquinone by di-O-methylation and HPLC detection is described. Fil: Sussmann, Rodrigo A. C.. Universidade de Sao Paulo; Brasil Fil: de Moraes, Marcilio M.. Universidade de Sao Paulo; Brasil Fil: Cebrián Torrejón, Gerardo. Universidad de Valencia; España. Universidade de Sao Paulo; Brasil Fil: Porta, Exequiel Oscar Jesús. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - …
Intestinal Scavenger Receptors Are Involved in Vitamin K 1 Absorption
2014
International audience; Vitamin K-1 (phylloquinone) intestinal absorption is thought to be mediated by a carrier protein that still remains to be identified. Apical transport of vitamin K-1 was examined using Caco-2 TC-7 cell monolayers as a model of human intestinal epithelium and in transfected HEK cells. Phylloquinone uptake was then measured ex vivo using mouse intestinal explants. Finally, vitamin K-1 absorption was compared between wild-type mice and mice overexpressing scavenger receptor class B type I (SR-BI) in the intestine and mice deficient in cluster determinant 36 (CD36). Phylloquinone uptake by Caco-2 cells was saturable and was significantly impaired by co-incubation with al…
Erratum to: Cetuximab-induced skin exanthema: prophylactic and reactive skin therapy are equally effective
2013
Purpose Treatment with cetuximab is accompanied by the development of an acneiform follicular skin exanthema in more than 80 % of patients. Severe exanthema (grade III/IV) develops in about 9–19 % of patients with the necessity of cetuximab dose reduction or cessation. Methods The study presented was a retrospective analysis of 50 gastrointestinal cancer patients treated with cetuximab in combination with either FOLFIRI or FOLFOX. One cohort of 15 patients received an in-house reactive skin protocol upon development of an exanthema. A second cohort of 15 patients received a skin prophylaxis starting with the first dose of cetuximab before clinical signs of toxicity. A third historic group o…
Vitamin K epoxide reductase activity in the metabolism of epoxides
1985
Abstract The importance of vitamine K epoxide reductase for the metabolism of a range of structurally diverse epoxides has been investigated. Vitamin K 1 epoxide is reduced by rat liver microsomes at a rate of 0.47 nmoles/g liver/min. The rate of menadione oxide reduction is not significantly higher than the non-enzymatic reduction rate. No measurable reduction of benzo[ a ]pyrene 4,5-oxide, benzo[ a ]pyrene 7,8-oxide, phenanthrene 9,10-oxide, styrene 7,8-oxide, and dieldrin has been detected, nor could trichothecene T-2 toxin inhibit reduction of vitamin K 1 epoxide. Thus, vitamin K epoxide reductase is very specific for vitamin K 1 epoxide. Taking into account the range of structurally di…
Effects of β-Carotene, Retinal, Riboflavin, α-Tocopherol and Vitamins C and K1 on Sister-chromatid Exchanges Induced by 3-Amino-1-methyl-5H-pyrido[4,…
1998
The vitamins and related compounds cited in the title were investigated for their abilities to modulate sister-chromatid exchanges (SCEs) induced by Trp-P-2 or cyclophosphamide (CP) in human peripheral lymphocyte cultures in the presence of an exogenous metabolizing system from rat liver. When inducer and test substances were given simultaneously, beta-carotene, retinal and alpha-tocopherol caused a dose-dependent decrease of SCE frequencies induced by Trp-P-2 and CP. Vitamin K1, however, brought about an identical effect with Trp-P-2 only, while with CP an initial decrease of SCEs was followed by a statistically significant re-increase at higher concentrations. Vitamin C was ineffective ag…
Dietary intake of vitamin K is inversely associated with mortality risk
2014
Vitamin K has been related to cardiovascular disease and cancer risk. However, data on total mortality are scarce. The aimof the present study was to assess the association between the dietary intake of different types of vitamin K and mortality in a Mediterranean population at high cardiovascular disease risk. A prospective cohort analysis was conducted in 7216 participants from the PREDIMED (Prevención con Dieta Mediterránea) study (median follow-up of 4.8 y). Energy and nutrient intakes were evaluated using a validated 137-item food frequency questionnaire. Dietary vitamin K intake was calculated annually using the USDA food composition database and other published sources. Deaths were a…
Low vitamin K1 intake in haemodialysis patients
2017
Background & aims Vitamin K acts as a coenzyme in the γ-carboxylation of vitamin K-dependent proteins, including coagulation factors, osteocalcin, matrix Gla protein (MGP), and the growth arrest-specific 6 (GAS6) protein. Osteocalcin is a key factor for bone matrix formation. MGP is a local inhibitor of soft tissue calcification. GAS6 activity prevents the apoptosis of vascular smooth muscle cells. Few data on vitamin K intake in chronic kidney disease patients and no data in patients on a Mediterranean diet are available. In the present study, we evaluate the dietary intake of vitamin K1 in a cohort of patients undergoing haemodialysis. Methods In this multi-centre controlled observati…