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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
341

The relationship between allergic diseases and vitamin D pathway genes and serum vitamin D levels in Chinese children. / 過敏性疾病與維生素D路徑的基因及血清維生素D水平之間的關係 / CUHK electronic theses & dissertations collection / Guo min xing ji bing yu wei sheng su D lu jing de ji yin ji xue qing wei sheng su D shui ping zhi jian de guan xi

January 2013 (has links)
Wang, Shuxin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 191-212). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese; appendixes includes Chinese.
342

Razvoj prediktivnog modela obogaćivanja prehrambenih proizvoda vitaminom D u Srbiji / Development of Predictive Model for Fortification of Foods with Vitamin D in Serbia

Milešević Jelena 19 April 2019 (has links)
<p>Kreirana je specijalizovana baza podataka o sadržaju vitamina D koja sadrži 981 analitički podatak prikupljen iz evropskih baza podataka, od čega je 658 (67%) izraženo u formi ukupnog vitamina D. Podaci o svim vitamerima pronađeni su za meso, obogaćene namirnice/formulacije i za ribu, dok su podaci o D3 pronađeni za ribu, meso i mlečne proizvode. Podaci o sadržaju vitamina D, iz srpske baze podataka o sastavu namirnica (BPSN), ažurirani su za ukupno 541 namirnicu, jelo i dijetetski suplement.<br />Da bi se upotpunio kvalitet podataka o vitaminu D u srpskoj BPSN, određen je sadržaj vitamina D u svežim konzumnim koko&scaron;ijim jajima proizvedenim na teritoriji Srbije. Analizirana su jaja iz intenzivne proizvodnje i iz malih domaćinstava. Analize su izvedene u laboratoriji Danskog Tehničkog Univerziteta (DTU) standardizovanom HPLC metodom. Sadržaj vitamina D u jajima iz intenzivne proizvodnje iznosio je 5,78 &mu;g/100g, a u jajima iz slobodnog uzgoja 2,99 &mu;g/100 g. Izračunati prosečni sadržaj vitamina D u svežim jajima iznosio je 4,39 &mu;g/100 g te je ovaj podatak unet u srpsku BPSN.<br />Uobičajeni unos vitamina D analiziran je programom SPADE u populaciji koju su činili ispitanici iz četiri regiona Srbije, ukupno 605 odraslih, od toga 54% žena. Ustanovljeno je da uobičajeni prosečni unos vitamina D iznosi 4&plusmn;1,4 &mu;g/dan, kod mu&scaron;karaca 4,3&plusmn;1,5 &mu;g/dan, a kod žena 3,7&plusmn;1,2 &mu;g/dan, &scaron;to je znatno niže od preporučenih vrednosti od 10 &mu;g/dan za procenjene prosečne potrebe (Estimated Average Requirement-EAR) i 15 &mu;g/dan za adekvatni unos (Adequate Intake &ndash;AI). Čak 95% srpske populacije ne dostiže EAR vrednosti.<br />Analiza ishrane srpske populacije pokazala je da su glavni nutritivni izvori vitamina D jaja, riba, meso i mlečni proizvodi. Konzumacija obogaćenih namirnica vitaminom D (obogaćenih i biljnih mleka, kakao praha, obogaćenih sokova, margarina i instant žitarica) identifikovana je kod trideset petoro ispitanika. Prateći kriterijume za odabir adekvatnih namirnica za obogaćivanje, a za potrebe dizajniranja prediktivnog modela, odabrano je 70 namirnica koje su sortirane u sedam karakterističnih grupa: beli hleb, mleko, jogurt, sir, pavlaka, jaja i paradajz pire.<br />Prediktivni model obogaćivanja namirnica baziran je na matematičkoj formuli kojom se izračunava količina vitamina D (fc) koju treba dodati određenoj namirnici, odnosno grupi namirnica. Izračunata količina zavisi od tri faktora:<br />- prosečne konzumacije date namirnice, ili grupe, u gramima na n-tom percentilu populacije,<br />- njenog (njihovog) procentualnog udela u dnevnom energetskom unosu,<br />- unosa vitamina D (u &mu;g/dan) na n-tom percentilu.<br />Odabrano je sedam scenarija koji su simulirani da bi se validirala efektivnost &bdquo;dodavanja&ldquo; vitamina D radi dostizanja preporučenih nutritivnih vrednosti. U optimalnom scenariju, AI je dostignut na 65. percentilu populacije, a unos vitamina D na 95. percentilu populacije bio je ispod 25 &mu;g/dan. U maksimalnom scenariju, 50% populacije bilo je između AI i gornjeg tolerisanog nivoa nutritivnog unosa (Upper Tolerable Intake Level-UL), pri čemu niko nije dostigao UL vrednosti. Na ovaj način definisane su optimalne i maksimalne količine vitamina D koje se mogu dodati odabranim namirnicama da bi se zadovoljile potrebe, odnosno korigovao unos vitamina D kod srpske populacije.</p> / <p>A specialized database on the content of vitamin D was created with 981 analytical data on vitamin D content obtained from European databases, of which 658 (67%) were expressed as total vitamin D. The data (for all vitamins) were mainly found for meat, enriched foods/formulations and fish, while D3 data was identified for fish, meat and dairy products. Updating data on vitamin D content in Serbian food composition database (FCDB) was done in 541 foods, dishes and dietary supplements. To enhance the quality of data in Serbian FCDB, content of vitamin D in fresh eggs from the farm and domestic production on the territory of Serbia has been determined. Analysis was performed in Danish Technical University-DTU, Denmark, using standardized HPLC method. Eggs from the farm contained 5.78 &mu;g vitamin D/100 g, while domestic eggs were 2.99 &mu;g vitamin D/100 g, and the average vitamin D content in fresh eggs - 4.39 &mu;g/100 g which value was inserted into Serbian FCDB. The usual dietary intake of vitamin D was analyzed using the SPADE program in the survey covering 605 adult respondents from four regions of Serbia, of which 54% were women. The average intake of vitamin D was found to be 4&plusmn;1.4&mu;g/day, which is 4.3&plusmn;1.5 &mu;g/day for men and 3.7&plusmn;1.2 &mu;g/day for women, and is significantly lower than the recommended Estimated Average Requirement (EAR) values (10 &mu;g/day) and Adequate Intake (AI) values (15 &mu;g/day). As many as 95% of Serbian population are not reaching the EAR values. Nutritional analysis of Serbian diet has shown that the main sources of vitamin D are eggs, fish, meat and dairy products. Consumption of vitamin D-fortified foods (fortified and plant milk, cocoa powder, fortified juices, margarine, and instant cereals) was identified in 35 subjects. Following the criteria for selecting adequate foods for fortification, for the needs of designing the model, 70 foods were selected that were sorted into 7 characteristic food groups: white bread, milk, yoghurt, cheese, sour cream, eggs and tomato puree.<br />The prediction model of food fortification is based on a mathematical formula that calculates the amount of vitamin D (fc) to be added to a particular food group in accordance with:<br />- the amount of consumption of that food vector and<br />- the percentage factor in the total energy intake of the considered foods (food vectors) in the observed population,<br />- the intake of vitamin D on n-th percentile.<br />Seven scenarios were simulated to validate the effect of addition of vitamin D toward reaching the given reference values. In the optimal scenario, AI was reached at the 65th percentile of the population, and vitamin D intake at 95th percentile was below 25 &mu;g/day. In the maximum scenario, 50% of the population was between AI and Upper Tolerable Intake Level (UL), while none has reached UL values. This defines the ranges of optimal and maximum values of vitamin D that, by being added to the chosen food-vectors, can help in reaching vitamin D requirements of Serbian population.</p>
343

Regulation of Vitamin D 25-hydroxylases : Effects of Vitamin D Metabolites and Pharmaceutical Compounds on the Bioactivation of Vitamin D

Ellfolk, Maria January 2008 (has links)
A 700bp portion of the promoter of CYP2D25, the porcine microsomal vitamin D 25-hydroxylase was isolated and sequenced. The computer analysis of the sequence revealed the existence of a putative VDRE at 220 bp upstream of the transcription start site. A CYP2D25 promoter-luciferase reporter plasmid was constructed in order to study the transcriptional regulation of the gene. Treatment with the vitamin D metabolites calcidiol and calcitriol suppressed the promoter, provided that the nuclear receptors VDR and RXR were overexpressed. Phenobarbital was also capable of suppressing the promoter if the nuclear receptors PXR or CAR were overexpressed. The 25-hydroxylases are not expressed solely in liver but in a wide array of other organs as well. It is therefore possible at least in theory to study the vitamin D 25-hydroxylation in human subjects using cells from extrahepatic organs, from which biopsy retrieval is easier than from the liver. Dermal fibroblasts are frequently used to study different pathological conditions in human subjects and they are easy to come by. Dermal fibroblasts were shown to express two vitamin D 25-hydroxylases: CYP27A1 and CYP2R1. The expression pattern of CYP2R1 displayed considerable interindividual variation. The fibroblasts were also capable of measurable vitamin D 25-hydroxylation, which makes dermal fibroblasts a possible tool in studying vitamin D 25-hydroxylation in human subjects. Little is known about the regulation of expression and activity of the human vitamin D 25-hydroxylases. Therefore dermal fibroblasts – expressing CYP2R1 and CYP27A1 – and human prostate cancer LNCaP cells, that express CYP2R1 and CYP2J2, were treated with calcitriol and phenobarbital and efavirenz, two drugs that give rise to vitamin D deficiency. Treatment decreased the mRNA levels of CYP2R1 and CYP2J2 provided that the treated cells also expressed the necessary nuclear receptors. CYP27A1 did not respond to any of the treatments. The treatments also managed to decrease the 25-hydroxylating activity of the cells. The results show that vitamin D 25-hydroxylases can be regulated by both endogenous and xenobiotic compounds.
344

Mechanisms regulating osteoblast response to surface microtopography and vitamin D

Bell, Bryan Frederick 11 November 2009 (has links)
A comprehensive understanding of the interactions between orthopaedic and dental implant surfaces with the surrounding host tissue is essential in the design of advanced biomaterials that better promote bone growth and osseointegration of implants. Dental implants with roughened surfaces and high surface energy are well known to promote osteoblast differentiation in vitro and promote increased bone-to-implant contact in vivo. In addition, increased surface roughness increases osteoblasts response to the vitamin D metabolite 1α,25(OH)2D3. However, the exact mechanisms mediating cell response to surface properties and 1α,25(OH)2D3 are still being elucidated. The central aim of the thesis is to investigate whether integrin signaling in response to rough surface microtopography enhances osteoblast differentiation and responsiveness to 1α,25(OH)2D3. The hypothesis is that the integrin α5β1 plays a role in osteoblast response to surface microtopography and that 1α,25(OH)2D3 acts through VDR-independent pathways involving caveolae to synergistically enhance osteoblast response to surface roughness and 1α,25(OH)2D3. To test this hypothesis the objectives of the studies performed in this thesis were: 1) to determine if α5β1 signaling is required for osteoblast response to surface microstructure; 2) to determine if increased responsiveness to 1α,25(OH)2D3 requires the vitamin D receptor, 3) to determine if rough titanium surfaces functionalized with the peptides targeting integrins (RGD) and transmembrane proteoglycans (KRSR) will enhance both osteoblast proliferation and differentiation, and 4) to determine whether caveolae, which are associated with integrin and 1α,25(OH)2D3 signaling, are required for enhance osteogenic response to surface microstructure and 1α,25(OH)2D3. The results demonstrate that integrins, VDR, and caveolae play important roles in mediating osteoblast response to surface properties and 1α,25(OH)2D3. Silencing of the β1 integrin in osteoblast-like MG63 cells significantly reduced osteogenic response to surface topography and 1α,25(OH)2D3. Silencing of the α5 subunit did not alter the response of MG63 cells to changing surface roughness or chemistry, although future work must confirm these results given similar cell surface α5 integrin expression observed in control and α5-silenced cells. Multifunctional RGD, KRSR, and KSSR coated surfaces show that RGD increased osteoblast proliferation and reduced differentiation, KRSR had no affect on osteoblast phenotype, and KSSR increased osteoblast differentiation. These results suggest that titanium surfaces can be modified to manipulate proliferation and differentiation and that RGD/KSSR functionalized surfaces could be further investigated for use as osteointegrative surfaces. The results using VDR deficient osteoblasts demonstrate that 1α,25(OH)2D3 acts via VDR-dependent mechanisms in cells cultured on titanium surfaces that support terminal differentiation. In caveolae deficient osteoblasts, 1α,25(OH)2D3 affected cell number, alkaline phosphatase activity, and TGF-β1 levels, although levels of osteocalcin and PGE2 were not affected. These results are consistent with the hypothesis that VDR is required for the actions of 1α,25(OH)2D3, but that caveolae-dependent membrane 1α,25(OH)2D3 signaling modulates traditional VDR signaling. The exact mechanisms for this interaction remain to be shown. Overall, these results are important in better understanding the role of β1 integrin partners in mediating osteoblast response to implant surfaces and in understanding how integrin signaling can alter osteoblast differentiation and responsiveness to 1α,25(OH)2D3 via genomic and non-genomic pathways.
345

Mutational analysis and engineering of the human vitamin D receptor to bind and activate in response to a novel small molecule ligand

Castillo, Hilda S. 22 January 2011 (has links)
Nuclear receptors (NRs) are ligand-activated transcription factors that regulate the expression of genes involved in all physiological activities. Disruption in NR function (e.g. mutations) can lead to a variety of diseases; making these receptors important targets for drug discovery. The ability to bind a broad range of 'drug-like' molecules also make these receptors attractive candidates for protein engineering, such that they can be engineered to bind novel small molecule ligands, for several applications. One application is the creation of potential molecular switches, tools that can be used for controlling gene expression. Gaining knowledge of specific molecular interactions that occur between a receptor and its ligand is of interest, as they contribute towards the activation or repression of target genes. The focus of this work has been to investigate the structural and functional relationships between the human vitamin D receptor (hVDR) and its ligands. To date, mutational assessments of the hVDR have focused on alanine scanning and residues typically lining the ligand binding pocket (LBP)that are involved in direct interactions with the ligand. A comprehensive analysis of the tolerance of these residues in the binding and activation of the receptor by its ligands has not been performed. Furthermore, residues not in contact with the ligand or that do not line the LBP may also play an important role in determining the activation profiles observed for NRs, and therefore need to be explored further. In order to engineer and use the hVDR in chemical complementation, a genetic selection system in which the survival of yeast is linked to the activation of a NR by an agonist, the hVDR gene was isolated from cDNA. To gain insight into how chemical and physical changes within the ligand binding domain (LBD) affect receptor-ligand interactions, libraries of hVDR variants exploring the role and tolerance of hVDR residues were created. To develop a comprehensive mutational analysis while also engineering the hVDR to bind a novel small molecule ligand, a rational and a random mutagenic approach were used to create the libraries. A variant, hVDRC410Y, that displayed enhanced activity with lithocholic acid (LCA), a known hVDR ligand, and novel activation with cholecalciferol (chole), a precursor of the hVDR's natural ligand known not to activate the wild-type hVDR, was discovered. The presence of a tyrosine at the C410 position resulting in novel activation profiles with both LCA and chole, and the fact that this residue does not line the hVDR's LBP led to interest in determining whether a physical or chemical property of the residue was responsible for the observed activity. When residue C410 was further assessed for its tolerance to varying amino acids, the results indicated that bulkiness at this end of the pocket is important for activation with these ligands. Both LCA and chole have reduced molecular volumes compared to the natural ligand, 1alpha, 25(OH)2D3. As a result, increased bulkiness at the C410 position may contribute additional molecular interactions between the receptor and ligands. Results obtained throughout this work suggest that the end of the hVDR's LBP consisting of two ligand anchoring residues, H305 and H397, and residue C410 tolerates structural variations, as numerous variants with mutations at these positions displayed enhanced activity. The receptor contains two tyrosines, Y143 and Y147, which were targeted for mutagenesis in one of the rationally designed libraries, located at the exact opposite end of the pocket. In an effort to gain further insight into the role of these residues at the other end of the LBP, mutagenesis assessing the tolerance of tyrosines 143 and 147 was performed. Overall, most changes at these positions proved to be detrimental to the function of the receptor supporting the hypothesis that this end of the LBP is less tolerant of structural changes, compared to the opposite end consisting of residues H305, H397 and C410. Overall, a better understanding of the structural and functional relationships between the human vitamin D receptor (hVDR) and its ligands was achieved. The effects of residue C410 on specificity and activation with the different ligands studied were unforeseen, as this residue does not line the receptor's ligand binding pocket (LBP). However, they serve as an example of the significant impact distant residues can have on receptor activation and also emphasize the important role physical properties of residues, such as volume, can play for specific ends of the LBP compared to chemical properties.
346

Analysen zu Interaktionen zwischen dem Vitamin-D-Rezeptor Signalweg und der Hedgehog Signalkaskade / Analyses of interactions between the vitamin D pathway and the Hedgehog signaling cascade

Fritsch, Anne 31 March 2014 (has links)
Der Hedgehog (Hh)-Signalweg ist an der Entstehung verschiedener Tumorentitäten beteiligt. Es wird vermutet, dass die Signalwegskomponente Patched (Ptch) physiologischerweise als Oxysterolpumpe dient und ein Molekül - vermutlich ein Vitamin D3 Derivat - sezerniert, welches den Hh Signalweg durch Bindung an das Transmembranprotein Smoothened (Smo) hemmt. Durch inaktivierende Ptch Mutationen wird die Sekretion dieses Moleküls vermutlich gestört, was zu einer Aktivierung des Signalwegs führt. Vorarbeiten lassen vermuten, dass es sich bei dem sezernierten Vitamin D3-Derivat um 1α,25(OH)2D3 (Calcitriol) handeln könnte. Da Calcitriol seine antitumorale Wirkung neben der Hemmung der Hh-Signalkaskade auch über die Aktivierung des Vitamin-D-Rezepor (Vdr) -Signalwegs vermitteln kann, sollten in dieser Arbeit mögliche Schnittpunkte der Hh-Signalkaskade, des Vdr-Signalwegs und des Calcitriol Metabolismus untersucht werden. Zunächst ergaben die Untersuchungen, dass Ptch-defiziente Rhabdomyosarkom Zellen, verglichen mit Wildtyp-Ptch Zellen, eine verminderte Calcitriol-Synthese aufweisen, die vermutlich durch eine herabgesetzte Aktivität der 1α Hydroxylase bedingt ist. Die dadurch verminderte Calcitriol Konzentration ist wahrscheinlich die Ursache der gleichzeitig erhöhten Hh Signalwegsaktivität in den Zellen. Dies bestätigten weitere Untersuchungen mit dem 1α Hydroxylaseinhibitor Itraconazol an Ptch-/- Zellen. Weiterhin konnte gezeigt werden, dass Itraconazol mit Calcitriol hinsichtlich der Hemmung des Hh-Signalwegs kooperiert. Die verstärkte Hemmung ist aber unabhängig von einer Itraconazol-abhängigen Herabsetzung der 24 Hydroxylaseaktivität. Zudem zeigten die Untersuchungen, dass Calcitriol (neben der Aktivierung des Vdr Signalwegs) den Hh-Signalweg in Ptch / Zellen effizienter hemmt als Cyclopamin. Weiterhin konnte gezeigt werden, dass Calcitriol auch mit Cyclopamin bezüglich der Hemmung der Hh-Signalkaskade kooperiert. Weitere Untersuchungen bekräftigen die Hypothese, dass Calcitriol, ähnlich wie der bekannte Smo-Inhibitor Cyclopamin, an Smoothened (Smo) bindet. Daneben weisen die Untersuchungen darauf hin, dass 1α,25(OH)2D3 den Hh-Signalweg zusätzlich über einen nicht-kanonischen, Suppressor of fused-unabhängigen Weg hemmen könnte. Transfektionsuntersuchungen an Gli-Knock-Out-Zellen zeigten, dass Gli3 möglicherweise die Vdr-Expression und dadurch auch die Calcitriol/Vdr-vermittelte Proliferationshemmung von Calcitriol reguliert. Schließlich konnte im Tiermodell für BCC die antitumorale Wirkung von 100 ng/kg/d Calcitriol gezeigt werden. Die Studie zeigte die effektive Wirkung von Calcitriol, wenn die Substanz ab einem frühen Tumorstadium verabreicht wird. Daneben scheint die Dauer der Behandlung eine entscheidende Rolle für die antiproliferative in vivo Wirkung von Calcitriol zu spielen.
347

PREVALÊNCIA DE DEFICIÊNCIA DE VITAMINA D E ANÁLISE DOS FATORES ASSOCIADOS EM CRIANÇAS SAUDÁVEIS DO AMBULATÓRIO DE PEDIATRIA DO HUSM / PREVALENCE OF VITAMIN D DEFICIENCY AND THE ANALYSIS OF ASSOCIATED FACTORS IN HEALTHY CHILDREN OF THE OUTPATIENT PEDIATRICS CLINIC OF THE SANTA MARIA UNIVERSITY HOSPITAL

Silva, Alliny Beletini da 22 August 2016 (has links)
Vitamin D deficiency is one of the most commented health issues at the moment, given the number of discoveries about its function in various tissues and organs. The principal action of vitamin D is related to calcium absorption and its implication in bone homeostasis, but, besides this, it has been implicated in several other diseases. Despite this huge interest in vitamin D, there are still few studies talking about vitamin D deficiency in children in our country, and especially in our region. Knowing the prevalence of vitamin D deficiency in specific place or region, it will be possible plan actions focusing prevention, early diagnosis and treatment, and thus to reduce complications and costs to public health. This study aims to determine the prevalence of vitamin D deficiency and the factors associated in healthy children of the outpatient pediatrics clinic of a university hospital in the central region of Rio Grande do Sul. This analytical cross-sectional study included 138 healthy children of the pediatrics clinic of the University Hospital of Santa Maria. The serum 25 (OH) D was performed by the Clinical Laboratory of the University Hospital. The associated factors were obtained through a questionnaire conducted by telephone. The results showed that the overall prevalence of vitamin D deficiency in the population studied was 42.7%, 12.3% with deficiency and 30.4% with insufficiency in vitamin D. The highest percentage of children with adequate levels occurred among infants, followed by preschoolers, schoolers and adolescents. The majority, 65.9%, received vitamin D supplementation on average by 21.6 (± 15.6) months. The principal risk factors identified were: the age group (preschoolers, schoolers and adolescents); residence in urban areas; no supplemental of vitamin D and lack of sun exposure. We conclude that the prevalence of vitamin D deficiency is high in the region studied, especially among adolescents. Besides age, no vitamin D supplementation and inadequate sunlight exposure are risk factors that increase the chance of insufficiency/deficiency in vitamin D. / A deficiência de vitamina D é um dos assuntos mais comentados da área da saúde na atualidade, face às várias descobertas sobre a sua função em diversos tecidos e órgãos. A ação mais conhecida da vitamina D é na absorção do cálcio e sua implicação na homeostase óssea, mas além disso, tem estudos comprovando a relação da vitamina D com diversas outras doenças. Apesar desse enorme interesse sobre a vitamina D, ainda existem poucos trabalhos na literatura falando sobre a deficiência de vitamina D em crianças em nosso país, e principalmente na nossa região. Conhecendo a prevalência da hipovitaminose D, em determinado local ou região, pode-se pensar em medidas de prevenção, diagnóstico precoce e tratamento, buscando assim reduzir as complicações e os custos para a saúde pública. Assim, o presente estudo tem por objetivo conhecer a prevalência de deficiência de vitamina D e os fatores associados à esta, em crianças saudáveis em seguimento em um ambulatório de pediatria de um hospital universitário, na região central do Estado do Rio Grande do Sul. Este estudo transversal analítico incluiu 138 crianças saudáveis em seguimento no ambulatório de pediatria do Hospital Universitário de Santa Maria. A dosagem sérica de 25(OH)D foi realizados pelo Laboratório de Análises Clínicas do HUSM, utilizando a coleta para exames de rotina já estabelecidos no ambulatório. Os fatores associados foram obtidos através de questionário realizado por telefone. Os resultados mostraram que a prevalência geral de hipovitaminose D na população estudada foi de 42,7%, sendo 12,3% das crianças deficientes e 30,4% insuficientes em vitamina D. O maior percentual de crianças com níveis adequados ocorreu entre os lactentes, seguido dos pré-escolares, escolares e adolescentes. A maioria, 65,9%, recebeu suplementação de vitamina D, em média, por 21,6 (±15,6) meses. Os fatores de risco identificados com maior significância foram: a faixa etária de pré-escolar/escolar/adolescente; residência em zona urbana; não suplementação de vitamina D e exposição solar. Conclui-se que a prevalência de hipovitaminose D é alta na região estudada, especialmente entre adolescentes. Além da faixa etária, a não suplementação de vitamina D e a exposição solar inadequada são fatores de risco, que aumentam a chance de insuficiência/deficiência em vitamina D.
348

Relação entre as concentrações séricas da vitamina D, polimorfismos do gene do VDR e síndrome metabólica em adultos e idosos / Relationship between serum concentrations of vitamin D, VDR gene polymorphisms and metabolic syndrome in adults individuals

Natielen Jacques Schuch 13 December 2011 (has links)
Introdução - O receptor de vitamina D (VDR) é expresso em vários tecidos e quando este se encontra na sua forma ativada, modula a expressão de diversos genes. Esses incluem variações dos níveis circulantes de 1,25(OH) 2 D , variações na densidade mineral óssea, secreção e sensibilidade à insulina em resposta à glicose, suscetibilidade à diabetes tipo 1 e 2, obesidade, dislipidemias e hipertensão arterial. Atualmente, evidências têm sugerido o envolvimento da vitamina D com a síndrome metabólica. Objetivo - Investigar a concentração sérica da vitamina D e sua relação com a síndrome metabólica e avaliar a potencial associação entre estes fatores com a presença de polimorfismos no gene do receptor de vitamina D (VDR) em indivíduos adultos. Métodos - Trata-se de um estudo transversal, onde foram avaliados 372 indivíduos adultos. Foram coletadas amostras sanguíneas para dosagens laboratoriais da 25(OH)D 3 , PTH e exames bioquímicos relacionados à SM, além disso foram realizadas avaliações antropométricas (peso, altura, IMC). A síndrome metabólica (SM) foi classificada usando o critério proposto pelo National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III). A resistência a insulina foi estimada pelo cálculo de HOMA IR e a função da célula pelo cálculo de HOMA . A 25(OH)D foi dosada por HPLC e a insuficiência foi determinada pelo ponto de corte da curva Roc (52,6nmol/l). Foram avaliados também PTH intacto e cálcio sérico. Os polimorfismos BsmI e FokI foram detectados através da digestão das enzimas de restrições específicas para cada polimorfismo e confirmados através da técnica PCR alelo específico (ASPCR) ou amplificação de mutação refratária (ARMs) nos indivíduos com e sem SM (52 por cento vs. 48 por cento , respectivamente). A análise estatística inclui construção da curva ROC, teste T de Student, testes de correlação, teste de equilíbrio de Hardy-Weinberg, ANOVA, regressão logística binária (Odds Ratio). Estas análises foram conduzidas no software SPSS para Windows, versão 18 e p < 0,05 foi considerado significante. Resultados - A idade média dos participantes foi 51(15) anos, o IMC médio 29(6) kg/m 3 2 e 48 por cento apresentaram SM. Como esperado, os 3 indivíduos com SM apresentaram maiores valores de idade 57(12) anos, IMC 32(6) Kg/m , circunferência de cintura 103(13) cm, pressão sistólica 138(17) mmHg e diastólica 83(10) mmHg, glicemia de jejum 98(12) mg/dl, triglicérides 165(76) mg/dl, índices HOMA-IR 2.2(1.7) e 116(95), e menores valores de colesterol HDL colesterol 41(11) mg/dl. Com relação às concentrações séricas de 25(OH)D propostas pela análise da curva ROC, 43 por cento dos indivíduos com SM e 57 por cento dos indivíduos sem SM apresentam insuficiência desta vitamina. Correlações entre 25(OH)D 3 3 com PTH (r = -0.153; p = 0.005) e com circunferência da cintura (r = -0.106; p = 0.05) foram observada em todos os participantes. Considerando os polimorfismos do gene VDR, nos pacientes com SM, não houve associação entre o polimorfismo BsmI e os componentes da SM, HOMA e IR, 25(OH)D e PTH. No entanto, indivíduos sem SM, mas com homozigose para polimorfismo BsmI (genótipo recessivo bb ), apresentaram concentrações mais baixas de 25(OH)D 3 3 do que aqueles com o genótipo BB normal. Além disso, os indivíduos com SM e heterozigose para o polimorfismo FokI (genótipo Ff) têm maiores concentrações de PTH e HOMA do que aqueles com genótipo normal FF. Nesse mesmo grupo, os indivíduos com o genótipo recessivo ff têm maior resistência à insulina do que aqueles com genótipo Ff. Por outro lado, os pacientes sem SM, mas carregando o genótipo Ff, apresentaram maiores concentrações de triglicerídeos e baixos níveis de HDL do que aqueles com genótipo FF. A presença de um alelo f no genótipo (Ff ou ff) é, aparentemente, o suficiente para aumentar os níveis de triglicérides e resistência à insulina, quando comparados ao genótipo normal FF. Conclusão - Os resultados demonstram que o polimorfismo FokI no gene VDR associa-se a resistência à insulina e maiores concentrações de PTH em pacientes que apresentam SM. Além disso, o polimorfismo BsmI associa-se a menores concentrações de 25(OH)D em indivíduos sem SM. Portanto, esses novos dados indicam que polimorfismos no gene do VDR estão associados a diferentes fenótipos dos componentes da SM / Introduction - The vitamin D receptor (VDR) is expressed in many tissues and when it is in its activated form modulates the expression of several genes. These include changes in circulating levels of 1,25(OH)2D3, variations in bone mineral density, sensitivity and secretion of insulin in response to glucose, susceptibility to type 1 and 2 diabetes mellitus, obesity, dyslipidemia and hypertension. Currently, evidences have suggested the involvement of vitamin D with the metabolic syndrome. Objective - To investigate the serum concentrations of vitamin D and its relationship with metabolic syndrome (MS) and to evaluate the potential association between these factors with the presence of polymorphisms in vitamin D receptor gene in individuals adults. Methods - This is a cross-sectional study, which evaluated 243 adults and elderly. We collected blood samples for measurements of 25(OH)D3, iPTH, biochemical tests related to MS, and anthropometric evaluation (weight, height, BMI) were also assessed. MS was classified using the criteria proposed by the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III). Insulin resistance and cell secretion were estimated by calculating HOMA IR and HOMA , respectively. The 25(OH)D3 was measured by HPLC and insufficiency was determined by the Roc curve cut-off (52.6 nmol/L). Intact PTH and serum calcium were also evaluated. The BsmI and FokI polymorphisms were detected by enzymatic digestion with specific enzymes and confirmed by allele specific PCR (ASPCR) or amplification of refractory mutation (ARM) in individuals with or without MS (52 per cent vs. 48 per cent , respectively). Statistical analyses include construction of Roc curves, Student T test, correlation tests, Hardy-Weinberg test, ANOVA, binary logistic regression (odds ratio), and TwoStep Cluster. These analyses were conducted with SPSS for Windows, version 18 and p < 0.05 was considered significant. Results - The mean age of participants was 51(15) years, mean BMI was 29(6) kg/m2, and 48 per cent of individuals presented MS. As expected, subjects with MS showed higher values of age (57(12) years), BMI was 32(6) kg/m2, waist circumference was 103(13) cm, systolic blood pressure was 138(17) mmHg, diastolic was 83(10) mmHg, fasting glucose was 98(12) mg/dl, triglycerides was 165(76) mg/dl, HOMA-IR was 2.2(1.7), HOMA was 116(95), and lower levels of HDL cholesterol was observed (41 mg/dl(11)). With respect to serum 25(OH)D3 proposed by ROC curve analysis, 43 per cent of individuals with MS and 57 per cent of individuals without MS presented insufficiency of this vitamin. Correlations between 25(OH)D3, iPTH (r = -0,153, p = 0.005), and waist circumference (r = -0,106, p = 0.05) were observed in all participants. Considering the VDR gene polymorphisms, in patients with MetSyn, there is no association among BsmI polymorphism and components of MetSyn, HOMA IR and , 25(OH)D3, and PTH. However, subjects without MetSyn, but with homozygosis for BsmI polymorphism (recessive bb genotype), presented lower levels of 25(OH)D3 than those with normal BB genotype. In addition, individuals with MetSyn and heterozygosis for FokI polymorphism (Ff genotype) have higher concentrations of PTH and HOMA than those with normal FF genotype. In this same group, subjects with the recessive ff genotype have higher insulin resistance than those with Ff genotype. On the other hand, patients without MetSyn, but carrying the Ff genotype, have higher concentration of triglycerides and lower levels of HDL than those with FF genotype. Interestingly, the presence of one allele f in the (Ff or ff) genotype is apparently enough to increase triglycerides levels and insulin resistance, when compared to the normal FF genotype. Conclusion - The results show that FokI polymorphism in the VDR gene is associated to insulin resistance and higher concentrations of PTH in patients with MetSyn. Moreover, BsmI polymorphism is related to a lower concentration of 25(OH)D3 in individuals without MetSyn. Therefore, the results indicated that VDR gene polymorphisms are associated to different phenotypes of MetSyn components
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Effects of Histone Deacetylase Inhibitors on Vitamin D Activity in Human Breast Cancer Cells

Savage, Brooke 01 January 2013 (has links) (PDF)
Breast cancer is one of the leading causes of death in women cancer cases worldwide. Cancer is the result of environmental and genetic factors that contribute to alterations in cellular control, proliferation, differentiation and apoptosis. Vitamin D is emerging as an important nutrient in the prevention and treatment of cancer due to its ability to modulate proliferation and apoptosis in vivo and in vitro. To accomplish this, Vitamin D exerts its biological activity by binding to a specific, high-affinity intracellular vitamin D receptor (VDR). VDR expression is identified in mammary cancer cell lines, but levels are reduced compared to non-cancerous cells, which limits vitamin D-induced gene expression. Our study investigated two compounds with histone deacetylase inhibitor (HDACI) activity, trichostatin A (TSA), and sulforaphane (SFN), and how they influence the expression of vitamin D-induced gene expression. By isolating mRNA to create cDNA, we were able to run RT-PCR to analyze the overall gene expression. The genes investigated were: CYP24A1, CYP27B1, VDR and TRPV6. We found that in MCF-7 breast cancer cells, 1,25(OH)2D3 treatment alone induced the expression of VDR, CYP24A1 and CYP27B1. TRPV6 mRNA expression was not evident. TSA alone increased expression of VDR and CYP24A1, but SFN alone had no effect. Co-treatments of 1,25(OH)2D3 and TSA raised CYP24A1, but not significantly. Co-treatments with SFN seemed to decrease CYP24A1 expression, not significantly. Our findings support further study of the effects of the HDACI TSA in breast cancer, and suggest that this HDACI may be beneficial in augmenting vitamin D cellular responsiveness.
350

Riskläkemedel för vitamin D-brist : Handläggning av patienter i Kalmar län.

Lönnbom, Ulrika January 2014 (has links)
Bakgrund: Det finns läkemedel som ger ökad risk för vitamin D-brist. En kartläggningsstudie av hur patientgrupper med olika riskläkemedel hanteras i Landstinget i Kalmar län har inte gjorts tidigare. En sådan studie är önskvärd, för att få en nulägesanalys och öka medvetenheten bland hälso-och sjukvårdspersonal om hur läkemedel påverkar D-vitaminstatus. Syfte: Syftet var att undersöka omfattningen av ordinerade riskläkemedel hos samtliga patienter, samt hos patientgruppen ≥75år och hur dessa handläggs avseende ordination av supplementering (samtidig behandling med läkemedel innehållande vitamin D3 / kalcium och vitamin D3,), provtagning och analysresultat avseende kalcidiol i serum. Metod: Riskläkemedel för vitamin D-brist identifierades. Inklusionskriterier för studien var patienter med de fördefinierade riskläkemedlen med ordinationer under 2012 och/eller 2013. Populationen som ingick i studien var patienter i Landstinget i Kalmar län. Data hämtades från patientdatasystemet Cambio Cosmic. Utifrån dessa data analyserades förekomst av supplementering, provtagning för S-25(OH)D kalcidiol och analyssvar. Materialet strukturerades efter respektive läkemedel avseende kön och ålder (≥75 år.) Resultat: 9118 individer ordinerades något av riskläkemedelen orlistat, sevelamer, kolestyramin, kolestipol, efavirenz, prednison, prednisolon, fenytoin, fenobarbital eller karbamazepin. 31% av patienterna som ordinerats riskläkemedel var ≥75 år. Totalt behandlades 22% med supplementationspreparat av de som ordinerats riskläkemedel. I åldersgruppen ≥75 år behandlades 43% med supplement. 61% av de supplementerade patienterna var ≥75 år. Totalt provtogs enbart 4,1% avseende kalcidiol av de som ordinerats riskläkemedel. Av dessa hade 37% av de provtagna en bristnivå av S-25(OH)D (≤50 nmol/L) vid första provtillfället. 57% av de som visade brist supplementerades. Endast 8,3% av de som hade en brist följdes upp med ytterligare en eller flera provtagningar. Av patienterna ≥75 år provtogs 4,1% av patienterna i åldersgruppen. Detta innebär att 31% av de som provtogs var ≥75år. 39% led brist. Av de patienter ≥75 år som hade led brist supplementerades 65% av individerna. Konklusion: Det finns förbättringsutrymme för implementering av kunskap kring riskläkemedel i Landstinget i Kalmar län. / Introduction: Some drugs increase the risk for vitamin D deficiency. To date, no survey has been performed in Kalmar County about how patients medicated with risk pharmaceuticals are handled. Such a survey would be desirable in order to increase knowledge among healthcare workers about how substances interfere with vitamin D status. Aim: The aim was to examine the extent to which risk pharmaceuticals are prescribed among all patients and among patients aged ≥75, and to investigate how these patients are treated with respect to supplementation (drugs containing vitamin D3 / Calcuim and vitamin D3), blood sampling and analysis of serum calcidiol levels. Method: Drugs interfering with vitamin D were identified. Inclusion criteria for the survey were patients that had been prescribed the pre-defined risk pharmaceuticals during 2012 and/ or 2013. The surveyed population was residents in Kalmar County. Data were collected from the patient database Cambio Cosmic. From these data analyzes were made about the occurrence of: supplementation, sampling of S-25(OH)D calcidiol and test results. The collected data were arranged by substance, gender and age (elderly aged ≥75). Results: 9118 patients were prescribed at least one of the risk pharmaceuticals; orlistat, sevelamer, cholestyramine, colestipol, efavirenz, prednisol, prednison, phenytoin, phenobarbital or carbamazepine. 31% of these were aged ≥75. Overall, 22% of the patients were prescribed supplements. Out of these, 61% were elderly. Among the patients that had been prescribed risk pharmaceuticals a minority, 4,1% of the patients were sampled for calcidiol. 37% of these had deficiency in S-25(OH)D (≤50 nmol/L). 8.3% of patients with a vitamin D deficiency were sampled more than once. Out of the patients with deficiency 57% were treated with supplements. Out of the elderly patients prescribed risk pharmaceuticals, 4.1% of the patients were tested for calcidiol. This means that 31% of the tested patients were aged ≥75 and 39% of these had a deficiency. Out of the elderly patients with deficiency, 65% were treated with supplements. Conclusion: In Kalmar County, much can be done in order to better implement the existing knowledge about drugs that increase the risk for vitamin D deficiency. / Betydelsen av bra D-vitaminstatus för äldres hälsa – Hur stor är förekomsten av D-vitaminbrist hos äldre i Kalmar län och hur påverkar läkemedel D-vitaminstatus

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