BACKGROUND The cholecalciferol inputs required to achieve or maintain any given serum 25-hydroxycholecalciferol concentration are not known, particularly within ranges comparable to the probable physiologic supply of the vitamin. OBJECTIVES The objectives were to establish the quantitative relation between steady state cholecalciferol input and the resulting serum 25-hydroxycholecalciferol co...

1. A competitive protein-binding assay for plasma 25-hydroxycholecalciferol was developed, using Sephadex LH-20 columns for the isolation of the sterol and a partially purified protein from rat serum as the binding protein. 2. The mean plasma 25-hydroxycholecalciferol in eighteen male and female normal volunteers was 38 5 SD 14 pmol/ml (1 5.2 & 5.6 nglml). 3. Levels of 25-hydroxycholecalciferol...

OBJECTIVES Although vitamin D is recognized as an important factor in bone health, its role in osteoarticular infections is unclear. We hypothesized that low vitamin D (25-hydroxycholecalciferol) levels are associated with a lower likelihood of treatment success in osteoarticular infections. METHODS This was a retrospective cohort study of patients with orthopedic infections who had a 25-hydr...

BACKGROUND Although solid cohort studies confirmed a preventative role for the anti-oxidant vitamin D in allergic asthma, a limited number of studies focused on allergic rhinoconjunctivitis (ARC). Here, we aimed to determine 25-hydroxycholecalciferol levels in tear and serum in young allergic rhinoconjunctivitis patients as compared to their apparently healthy matched controls. METHODS In tot...

INTRODUCTION AND OBJECTIVES The purpose of this study was to evaluate the concentration of 25-hydroxycholecalciferol and parameters of calcium-phosphate metabolism at different periods of relapsing-remitting multiple sclerosis (RRMS). MATERIALS AND METHODS Forty-five patients, residents of Poland (49°-50°, N), were enrolled in the study, i.e. 15 immediately after the diagnosis of RRMS, 15 at ...

INTRODUCTION Psoriasis is a hyperproliferative disorder of the skin, and vitamin D analogs are widely used in its treatment. It is evident that ultraviolet radiation enables vitamin D3 (cholecalciferol) formation in the epidermis, and this product is further converted into the active metabolites 25-hydroxycholecalciferol and 1,25-hydroxycholecalciferol, which exert several important effects on ...

The formation of 1,25-dihydroxycholecalciferol from 25-hydroxycholecalciferol by chick kidney homogenates is inhibited by increasing concentrations of Ca(2+). The apparent K(m) for the hydroxylation reaction is 1x10(-7)m, significantly lower than that reported for isolated mitochondria. Separated cytoplasmic and particulate fractions are inactive, but on recombination activity is restored, poss...

The prior administration of actinomycin D prevents the metabolism of [(3)H]25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol, a metabolite of vitamin D(3) that is effective in the stimulation of intestinal calcium transport. In this paper, the question of whether the response of intestinal calcium transport to 1,25-dihydroxycholecalciferol is sensitive to actinomycin D was examined. Wh...

Serial measurements of 51Cr edetic acid clearance were made over a period of one year in two groups of 8 children, in a double blind trial of 1 alpha-hydroxycholecalciferol (10 ng/kg/day) and calciferol (670 ng/kg/day). Glomerular filtration rate (GFR) at the beginning of the trial was 20-50 ml/min/1.73 m2; it rose in the children given 1 alpha-hydroxycholecalciferol (group A) after 6 months bu...