Plasma vitamin D

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Relationship between insulin resistance and plasma vitamin D in adults

Relationship between insulin resistance and plasma vitamin D in adults

Abstract: A recent relationship between vitamin D deficiency and the risk of type 2 diabetes mellitus (T2DM) and insulin resistance has been established through several studies. Research suggests a correlation between serum vitamin D and glycemic status measures. The aim of this study was to investigate the relationship between the plasma vitamin D levels (25[OH]D) and the factors linked to insulin resistance in a representative sample of Canadians ranging in age from 16–79 years. Data were used from the Canadian Health Measures Survey where direct measures of health and wellness were reported from 1,928 subjects. These data were gathered from March 2007–February 2009 at 15 sites selected through a multistage sampling strategy. An inverse relationship between insulin resistance and plasma vitamin D level in both men and women was observed. This study provides additional evidence for the role of vitamin D in T2DM. If causally associated, the supplementation of vitamin D may help in preventing insulin resistance and subsequent T2DM.

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Plasma Vitamin D Concentration Influences Survival Outcome After a Diagnosis of Colorectal Cancer

Plasma Vitamin D Concentration Influences Survival Outcome After a Diagnosis of Colorectal Cancer

variables. We first examined the association between vitamin D and CRC- specific and all-cause mortality by using Kaplan-Meier survival analysis. Cox proportional hazards models were used to calculate hazard ratios (HRs), adjusting the analysis for other relevant factors. Test of the proportional hazards assumptions was performed. HRs were calculated for vitamin D tertiles, with the lowest category as the reference. To explore effect modifica- tion, we assessed the risk in an analysis stratified for cancer stage. Trend tests were calculated based on 25-OHD as a continuous variable. P ⬍ .05 was considered statistically significant unless otherwise stated. Main effects of VDR polymorphisms and haplotypes and their multiplicative interaction with vita- min D on survival were assessed by using a Cox proportional hazards model.

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The analysis of the plasma vitamin D of the pre-school children

The analysis of the plasma vitamin D of the pre-school children

Samples are plasmas of preschool children (12-59 months). Their samples are obtained by the pediatric Department of Hospital University of Tlémcen (CHU) from three different areas of Tlémcen (Algerian willaya is located in the Northern West): coastal Northern area, the central mountainous area, and the southern steppe area. Each sample was conducted a questionnaire. Volume 2 ml of blood for each child was collected in Lithium heparin tube protected from light by a foil pouch. These blood samples are transported to the laboratory in a cooler where they were centrifuged at 5000 tr/ min [5]. Plasma obtained in an amount of 1 ml was pipetted into black and placed in tubes 2 aliquots (a and b) 0.5 ml for each. The tube "a" was reserved for the determination of Cholecalciferol and tube "b" used double as a backup or for further study on other micronutrients. The foil-covered tubes were frozen at -25 ° C.

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Maternal plasma vitamin D levels and associated determinants in late pregnancy in Harare, Zimbabwe: a cross sectional study

Maternal plasma vitamin D levels and associated determinants in late pregnancy in Harare, Zimbabwe: a cross sectional study

Our finding of significantly higher maternal 25 (OH) D concentrations in HIV-infected women is in discordance with findings from a number of studies that have reported an association between HIV infection and lower mean plasma values of maternal 25 (OH) D [1, 3, 4]. We specu- late this difference could have been due to the effect of cART. However, the effects of cART on vitamin D are regi- men dependent. Some drugs are associated with lower levels and some with higher levels. Although not assessed in this study, prolonged exposure to sunlight and improved well-being could also have contributed to the higher mater- nal 25 (OH) D levels.

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Human plasma transport of vitamin D after its endogenous synthesis

Human plasma transport of vitamin D after its endogenous synthesis

ultracentrifuged to provide a rapid separation of proteins of density < and > 1.3 g/ml. Upper and lower phases and serial fractions were analyzed for vitamin D3 (extraction, HPLC), cholesterol (enzyme assay), and human DBP (hDBP) (radial immunodiffusion). Total plasma vitamin D (basal level < 1 ng/ml) increased by 10 h and peaked at 24 h (9 +/- 1 ng/ml). 98% of the D3 remained at the density > 1.3 layers for up to 7 d, whereas cholesterol (> 85%) was detected at density < 1.3 and all of the hDBP was at density > 1.3. In three volunteers who each ingested 1.25 mg of vitamin D2, the total plasma D2 increased to 90 +/- 32 ng/ml by 4 h, and the D2 was evenly distributed between the upper and lower layers at 4, 8, and 24 h after the dose, indicating a continuing association of the vitamin with chylomicrons […]

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The effects of a vitamin D randomised controlled trial on muscle strength and power in female adolescent athletes : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Human Nutrition at Massey University,

The effects of a vitamin D randomised controlled trial on muscle strength and power in female adolescent athletes : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Human Nutrition at Massey University, Albany, New Zealand

In view of the fact that gymnasts and dancers are at a high risk for vitamin D deficiency, and that the necessary strength required for performance in these sports may be compromised, there is a demand for a well-designed, placebo-controlled intervention study. Upon the commencement of the present study, there had been no randomised controlled trials published on the direct effect of vitamin D supplementation on muscle function in any athletic population. Some researchers have hypothesised that the creation of a double-blind, placebo-controlled, multiple-dose crossover study with long washout periods using high doses - such as 2000, 4000, and 6000 IU of vitamin D per day - could determine if peak athletic performance levels exist for any particular serum 25(OH)D concentration (Cannell, Hollis, Sorenson, Taft, & Anderson, 2009). Alternatively, participants could receive the dose required to increase their own serum 25(OH)D concentrations to 100 nmol/L, theoretically regarded to be associated with peak neuromuscular performance (Bischoff-Ferrari, Dietrich, Orav, Hu, et al., 2004). However, there are ethical concerns in identifying without treating a vitamin D deficient control group, as well as the practical difficulties concerning time and participant numbers.

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ALTERATION IN PLASMA HOMOCYSTEINE, VITAMIN D, FOLATE AND VITAMIN C CONCENTRATION IN SCHIZOPHRENIC PATIENTS DUE TO GLUTEN FREE DIET

ALTERATION IN PLASMA HOMOCYSTEINE, VITAMIN D, FOLATE AND VITAMIN C CONCENTRATION IN SCHIZOPHRENIC PATIENTS DUE TO GLUTEN FREE DIET

The metabolism of Homocysteine is most highly affected by the Folate level and also by numerous environmental factors, such as food, in addition to genetic factors, typically MTHFR. 21 An increase in plasma Homocysteine is brought about by hypertension, age, vitamin B2, the male gender, vitamin B6, Creatinine, smoking, alcohol consumption, and coffee. Also seeing the option that the patients in our study had a low-Folate diet because they were hospitalized in a mental hospital, where a diet rich of Folate was inaccessible and they are also on gluten free diet which is probably low in Folate so it was assumed that there could be many schizophrenic patients who have a Folate-sensitive Homocysteine metabolism disorder. [22] The schizophrenic patients who have a Folate- sensitive Homocysteine metabolism disorder, in these patients the plasma Homocysteine level was considerably higher. [6]

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Plasma 25-Hydroxy Vitamin-D and Risk of Breast Cancer: A Case Control Study

Plasma 25-Hydroxy Vitamin-D and Risk of Breast Cancer: A Case Control Study

normal mammary tissue which induces a program of genes that suppresses proliferation and stimulates differentiation in the normal mammary gland. This hypothesis predicts that dysregulation of vitamin-D-receptor-mediated gene expression in the mammary gland will alter mammary gland development or function and possibly predispose cells to transformation. Breast cancer death rates tended to be higher in areas with low winter sunlight levels and lower in sunny areas (Gorham et al., 1989). Women regularly exposed to sunlight and consumers of above average amounts of vitamin D had significantly lower incidence of breast cancer (John et al., 1999). Women in the lower quartile of serum 1, 25(OH) 2 D had a risk of breast cancer 5 times higher than those in the higher quartile

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Maternal vitamin D depletion alters DNA methylation at imprinted loci in multiple generations

Maternal vitamin D depletion alters DNA methylation at imprinted loci in multiple generations

Fig. 4 Maternal vitamin D deficiency perturbs DNA methylation at imprinted regions in adult G1 soma (liver) and germline (sperm). a Schematic representation of imprinted regions assessed for DNA methylation changes. White, gray, and black lollipops indicate unperturbed methylation states from fully hypomethylated to partially and fully hypermethylated alleles, respectively. Location of lollipop and location of arrows indicates parental methylation or expression from maternal alleles (above gene) and paternal allele (below gene); b – c Bar graphs depict average DNA methylation across samples in the respective treatment group assayed in adult G1 liver (b) and sperm (c) for each sample analyzed (in order from left to right N = 10, 11, 10, 9 for all loci except Grb10 N = 10, 10, 9, 8 and N = 10, 10, 10, 9 liver and sperm, respectively). For each sample, the average methylation for all CpGs assayed across the locus is represented as a dot within the bar graph (see the “ Methods ” section). DMR differentially methylated region, Cbs CTCF binding site, ICR imprinted control region. Median values are indicated and linked by a horizontal line between box and whisker plots. Asterisks (*) or (***) indicate p value <0.05 or 0.005 determined by t test within each cross; panel above each graph lists all statistically significant (p value <0.05) comparisons determined by regression analysis for overall diet-dependent effects (diet), diet- independent parent of origin effects (PO), and diet-dependent parent of origin effects (diet × PO). n.s. not significant

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Role of plasma gelsolin and the vitamin D binding protein in clearing actin from the circulation

Role of plasma gelsolin and the vitamin D binding protein in clearing actin from the circulation

We determined the plasma kinetics of both actin and complexes of actin with the two high affinity actin-binding proteins of plasma, gelsolin, and vitamin D-binding protein (DBP). Actin is cleared rapidly from the plasma by the liver (half-disappearance time, 0.5 h). Using radiolabeled actin-binding proteins, we found that actin accelerated the clearance of both plasma gelsolin and the vitamin D-binding protein. In separate experiments we found that DBP-actin complexes were cleared more quickly than gelsolin-actin complexes, at a rate comparable to the clearance of actin from the blood. A low affinity interaction (dissociation constant, 2.9 X 10(-4) M) between actin and fibronectin was found, suggesting that little actin will bind to fibronectin in plasma. We conclude that while plasma gelsolin and DBP may both clear actin from the circulation, DBP appears to play a more important role. By so doing, DBP may conserve the filament-severing activity of plasma gelsolin.

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The turnover and transport of vitamin D and of a polar metabolite with the properties of 25 hydroxycholecalciferol in human plasma

The turnover and transport of vitamin D and of a polar metabolite with the properties of 25 hydroxycholecalciferol in human plasma

Four normal men were injected intravenously with physiological doses (6 µg) of vitamin D 3 - 1,2- 3 H. Serial samples of plasma were collected for 50 days. Total lipid extracts were chromatographed on silicic acid columns or thin-layer plates in order to characterize the radioactive components. Labeled vitamin D 3 disappeared rapidly from plasma (initial half- life approximately 12 hr); after 7 days unchanged vitamin D 3 represented less than 1% of circulating radioactivity. Coincident with vitamin D 3 disappearance a more polar labeled metabolite appeared with chromatographic and other properties identical with those of 25- hydroxycholecalciferol. The disappearance of the more polar metabolite was relatively slow with a half-life of 19.6 ±0.6 days. A similar half-life was seen in a fifth subject, injected with 80 µg of vitamin D 3 - 3 H. Most (approximately 92%) of the plasma total radioactivity was represented by this component throughout the study. Plasma samples collected at various times were adjusted to density (d) 1.21 and were ultracentrifuged to separate plasma lipoproteins from proteins with d > 1.21. In all samples, almost all (mean 94%) of the radioactivity was found in association with proteins of d > 1.21. This observation was confirmed by bioassay, measuring uptake of 45 Ca by intestinal slices. All plasma bioassayable vitamin D was found in association with proteins of d > 1.21; 55% of bioactivity was found in the chromatographic fraction corresponding […]

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Metabolism of Vitamin D3 3H in Vitamin D Resistant Rickets and Familial Hypophosphatemia

Metabolism of Vitamin D3 3H in Vitamin D Resistant Rickets and Familial Hypophosphatemia

The fate of an intravenous dose of tritiated vitamin D 3 was studied in seven normal subjects, four children with vitamin D-resistant rickets, and four adults with a familial history of vitamin D-resistant rickets and persistent hypophosphatemia. An abnormal metabolism of vitamin D in vitamin D-resistant rickets was defined and characterized by a decrease in the plasma fractional turnover rate, a marked increase in plasma water-soluble metabolites, and a relative decrease in the conversion of vitamin D to a polar, biologically active metabolite. Alterations in vitamin D metabolism in the adults with persistent hypophosphatemia were similar but less severe than those of affected children with vitamin D-resistant rickets. It is tentatively concluded that the abnormalities in vitamin D metabolism documented in

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Vitamin D and Vulnerable Carotid Plaque

Vitamin D and Vulnerable Carotid Plaque

One limitation of our study is its cross-sectional nature, mak- ing it difficult to determine causation between low vitamin D levels and carotid IPH. Another limitation is that unknown con- founders may exist that we did not have data to control for in the regression analysis. These would include variables related to both predictor (vitamin D) and outcome (IPH). While we evaluated multiple factors that may influence both vitamin D levels and carotid IPH, including age, sex, body mass index, angiotensin system markers, and carotid markers including plaque thickness, we did not find a significant association between IPH and any of the factors listed except for plaque thickness. Still, it is possible that low vitamin D levels are linked to some other undiscovered confounder or sedentary lifestyle, which even surveys may fail to appropriately quantify. 51 Finally, our study recruited patients

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Not enough vitamin D

Not enough vitamin D

Low levels of VTD are considered a major public health  problem in Canada, especially during the winter. Those  with  risk  factors  should  be  screened  for  low  25(OH)D  levels  and  repletion  therapy  instituted  if  needed.  Researchers  have  estimated  that  the  oral  dose  of  vita- min D3 to attain and maintain 25(OH)D levels >80 nmol/ L  is  2200  IU/d  if  baseline  levels  are  20  to  40  nmol/L,  1800 IU/d if levels are 40 to 60 nmol/L, and 1160 IU/d if 

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Vitamin D in obesity

Vitamin D in obesity

If obese people are truly vitamin D deficient, there may be implications for systems other than bone. Vitamin D deficiency has been associated with a large number of disorders, such as auto-immunity, cancer, neurodegenerative disease and metabolic syndrome. However, there is not yet clear evidence for a causative role of vitamin D deficiency in many of these conditions 32 . Obesity does increase the risk for several of these disorders but there are other possible mechanisms than low vitamin D for these associations, and the interaction of vitamin D and obesity in causation has not yet been clearly characterised 33 .

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Vitamin D deficiency: cognition, mortality and resource utilisation   prospective associations

Vitamin D deficiency: cognition, mortality and resource utilisation prospective associations

Ginde et al performed a small prospective observational pilot study to evaluate the association of Vitamin D deficiency (<75nmol/L) and higher sepsis severity in Emergency Department (ED) patients (Ginde et al., 2011). A total of 81 patients were recruited, aged over 18 years with suspected infection as identified by the admitting physician. Patients were classified as having sepsis if they had suspected infection with two or more Systemic Inflammatory Response Syndrome (SIRS) markers. Severe sepsis was presence of suspected infection with one or more organs acutely dysfunctional. Other markers of illness severity used in the study were the Acute Physiology and Chronic Health Evaluation (APACHE) and Sequential Organ Failure Assessment (SOFA) scores. The median age of participants was 62 years and median Vitamin D level was 52nmol/L. Participants were assessed at baseline and at 24 hours. Those with lower 25(OH)D levels at baseline were more likely to be older, male and white in ethnicity. Lower Vitamin D levels were also associated with higher SOFA and APCHE scores on admission and higher prevalence of severe sepsis. Lower Vitamin D levels were associated with increased SOFA scores at 24hours from baseline. Patients with lower Vitamin D levels had lower lactate levels and higher Iinterleukin-6 (IL-6) and IL-1 levels on admission.

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ROLE OF VITAMIN E ON OXIDATIVE STRESS IN SMOKERS

ROLE OF VITAMIN E ON OXIDATIVE STRESS IN SMOKERS

erythrocytes from smokers are more susceptible to lipid peroxidation (25). This study demonstrated that vitamin E reduces the susceptibility of erythrocytes to lipid peroxidation. The end product of lipid peroxidation, MDA was measured by fluorometric determination. Although this assay is not specific only for MDA and measures other substance that can react with thiobarbituric acid and give rise to the colored end points detected, the modifying effect of vitamin E on the generation of TBA-reacting species implies that it is a valid indicator of peroxidation in vitro.

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Vitamin D: the role of the sunshine vitamin

Vitamin D: the role of the sunshine vitamin

There is an association between inadequate Vitamin D levels and obesity (Alemzadeh et al. 2008; Sanchez-Hernandez et al. 2005; Renzaho et al. 2011; Brock et al. 2010). A relatively recent systematic review of 14 studies found an association between VDD and obesity related disorders (Renzaho et al. 2011) and another study found a relationship between VDD and BMI index of above thirty (Brock et al. 2010). It is also known that obesity is a common problem in people with mental health ailments, therefore, VDD is likely to be prevalent in this population(Phelan et al. 2001). More importantly, emerging evidence suggest a link between VDD and the aetiology of various mental health problems such as schizophrenia, depression, Alzheimer’s disease and anxiety. Specifically, there is a strong link between vitamin D and neurodevelopmental ailments. This is particularly provocative as we now consider a number of psychiatric illnesses neurodevelopmental in origin. For this reason, it is important to review evidence that support the link between VDD and neurodevelopment.

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AN ASSESSMENT OF INTERACTION BETWEEN PLASMA LEVEL OF VITAMIN D AND ATRIAL FIBRILLATION IN PATIENTS UNDERGOING CABG

AN ASSESSMENT OF INTERACTION BETWEEN PLASMA LEVEL OF VITAMIN D AND ATRIAL FIBRILLATION IN PATIENTS UNDERGOING CABG

Other studies show an increase in serum myocardial oxidative markers such as Peroxynitrite and Superoxide in atrial fibrillation after surgery. [10,11] Antioxidants such as vitamin C, N- acetylcysteine and statins lower serum levels of oxidants.4 In recent years, there has been a growing interest toward the role of vitamin D on cardiovascular health. [12,13] Lack of vitamin D is related to hypertension, [14,15] stroke, [16,17] Myocardial Infarction16 and other cardiovascular related diseases such as diabetes mellitus. [18] The main sources of vitamin D are sunlight, diet and supplements. Plasma 25- hydroxyvitamin D level is the most accurate method to assess vitamin D deficiency. [7] A plasma 25-hydroxy vitamin D level between 32 to 50 ng/ml is considered as the normal range. [19]

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Association between vitamin D plasma concentrations and VDR gene variants and the risk of premature birth

Association between vitamin D plasma concentrations and VDR gene variants and the risk of premature birth

methodologies, definitions of vitamin D deficiency, tim- ing of supplementation, and dose of supplementation [34]. A recent Cochrane review [39] showed evidence from 3725 pregnant women enrolled in 22 studies, sug- gesting that vitamin D supplementation alone during pregnancy potentially attenuates the risk of preeclampsia in comparison to placebo or no intervention. Also, it may have small or even no difference for the risk of pre- mature birth. Other review raised evidence from nine studies involving 1916 pregnant women and suggested that the risk of preeclampsia is reduced when supple- mentation with vitamin D and calcium is performed, al- though may increases risk of preterm birth. Other than that, the benefits or harms of vitamin D supplementa- tion alone or combined with calcium and other vitamins and minerals during pregnancy for mother and children remains unclear [39].

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