Dissertationen zum Thema „B12 vitamins“
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1
Presoto, Ana Elisa Ferreira. „Vitaminas do complexo B e ferro em farinhas de cereais“. Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/9/9131/tde-21112017-145753/.
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As vitaminas do complexo B e o ferro estão presentes em farinhas de cereais, alimentos amplamente consumidos pela população brasileira. O teor natural desses compostos em farinhas de cereais pode ser significativo no cálculo de uma dieta bem balanceada e o consumo de produtos industrializados enriquecidos com vitaminas do complexo B e ferro ajuda a contribuir na ingestão diária recomendada desses micronutrientes. Tabelas Mundiais de Composição de Alimentos apresentam dados incompletos das vitaminas do complexo B e do ferro em farinhas de cereais. No Brasil, a adição de ácido fólico e ferro em farinhas de milho e trigo produzidas para fins industriais é obrigatória desde 2002. Deste modo, para a adequação dos teores de rotulagem de produtos enriquecidos com vitaminas e ferro se fazem necessários o desenvolvimento e a validação de metodologias analíticas confiáveis e sensíveis para análise de vitaminas do complexo B e ferro em alimentos que apresentam tais micronutrientes em quantidades baixas, porém significativas, que correspondem aos teores naturalmente presentes. O objetivo do presente trabalho é a avaliação dos teores de sete vitaminas do complexo B (B1, B2, B6, ácido pantotênico, ácido fólico, niacina e biotina) e ferro em cinco farinhas de cereais (aveia, arroz, cevada, milho e trigo) utilizadas como matéria prima de produtos enriquecidos na indústria alimentícia, utilizando métodos validados.Complex B vitamins and iron are present in some cereal foods, a kind of food largely consumed by Brazilian people. The total of these micronutrients can be significant at the dairy ingestion portion and in the consume of industrialized products enriched with complex B vitamins and iron contribute in the recommended dietary intake of these micronutrients. Table of food composition do not report complete data of complex B vitamins and iron in cereal flours. In Brazil, since 2002 the addition of folic acid and iron in com and wheat flours is compulsory. Therefore, to adapt the label of some products enriched with vitamins and iron, there is necessary the development and validation of analytical methods. These methods must be reliable and with enough sensitivity to analyse complex B vitamins and iron, in low concentration, wich are natural content in food. The purpose of this work is the evaluation, with validated methods, of the content of seven complex B vitamíns (B1, B2, B6, niacin, folic acid, pantothenic acid and biotin) and iron in five kinds of cereal flours (oat, rice, barley, com and wheat). These raw materiais are used in food industry in order to enrich the industrialized products.
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Steluti, Josiane. „Folato, vitamina B6 e B12: Ingestão dietética, níveis sanguíneos e relação com a concentração sérica de homocisteína em adolescentes de Indaiatuba, SP“. Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/6/6138/tde-17112010-120013/.
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Introdução: O folato e outras vitaminas do complexo B estão metabolicamente relacionadas à elevação sanguínea do aminoácido homocisteína (hcy). Este, por sua vez, se mostrou associada ao aumento de risco de eventos adversos, sobretudo as doenças cardiovasculares. Objetivo: Investigar a ingestão dietética e níveis sanguíneos das vitaminas folato, B6, e B12, e sua relação com a concentração sérica de hcy, entre adolescentes Métodos: Estudo observacional, transversal, em adolescentes de ambos os sexos, faixa etária de 16 a 19 anos, foi conduzido na escola de ensino técnico da cidade de Indaiatuba-SP-Brasil. Coletou-se registro alimentar de três dias não consecutivos. Os valores dos nutrientes referentes aos registros foram obtidos no software NDSR. Para a estimativa da dieta habitual pela remoção da variabilidade intrapessoal e a prevalência de inadequação da ingestão pelo método da EAR como ponto de corte, utilizou-se o PC-Side, versão 1.0. As análises bioquímicas de folato, B6, B12 e hcy foram conduzidas de acordo com os métodos aceitos na literatura científica. Todas as análises estatísticas foram realizadas no STATA® versão 10.0 considerando o nível de significância 5%. Resultados: O estudo foi conduzido com 99 adolescentes, sendo 58,6% do sexo feminino e média de idade de 17,6 (dp 0,9) anos. As médias da concentração sérica de folato, B6 e B12 foram de 9,2 (dp 3,4) ng/ml, 18,7 (dp 5,1) nmol/L e 397,5 (dp 188,4) pg/ml, respectivamente. 15,2% dos adolescentes apresentavam inadequação da ingestão de folato, 10,2%, de B6 e <1%, de B12. Os alimentos que mais contribuíram para a ingestão dos nutrientes foram: pão francês (23,1%), macarrão (9,7%) e feijões (8,2%) para folato; arroz branco (9,9%), carne de frango (5,7%) e carne bovina (4,2%) para B6, e carne bovina magra (16,4%), leite integral (15%) e carne bovina gorda (12,3%) para B12. Em relação à hcy, as médias foram de 15,4 (dp 10,2) µmol/L nos meninos e 8,2 (dp 2,2) µmol/L nas meninas. Dos meninos, 25% apresentavam valores séricos de hcy superiores a 15 µmol/L e diminuição da média sérica de folato e B12 quanto maior o tercil do nível sérico hcy (p<0,005). Conclusão: As prevalências de inadequação da ingestão folato, B6 e B12 mostraram-se baixas, possivelmente em decorrência da melhoria do acesso e disponibilidade de alimentos, inclusive dos alimentos processados que contêm entre os ingredientes as farinhas fortificadas com ácido fólico. No entanto, os feijões, ainda se destacaram como um dos alimentos que contribuíram para a ingestão desse nutriente. Além disso, os adolescentes do sexo masculino têm altos níveis séricos de hcy e apresentaram uma tendência de queda das médias da concentração sérica de folato e B12 quanto maior o tercil de hcy.Introduction: Folate and the metabolically related B vitamins are intimately connected with metabolic pathways of homocysteine (hcy). Epidemiologic studies have shown that increased total homocysteine concentration is an independent predictor for a number of human diseases, especially, cardiovascular diseases. Objective: to investigate the dietary intake and status of folate, related B-vitamin, and the relationship to total homocysteine concentration among adolescents. Methods: A cross-sectional study was conducted among adolescents, both genders, aged 16 to 19 years, in a public school of Indaiatuba, São Paulo. Dietary intake was measured using three-day dietary record. The energy and nutrients were computed using Nutrition Data System for Research software. The usual intake and prevalence of inadequate by EAR cut-point method were estimated using PC-SIDE, version 1.0. Biochemical analyses were determined according the methods recommended by the scientific literature. All statistical analyses were performed using STATA, version 10.0. A two-tailed p value <0.05 was considered significant. Results: The study was conducted among 99 adolescents, 58 (58.6%) were girls, mean age of 17.6 (SD 0.9) years old. The means of folate, B6 and B12 vitamins status were of 9.2 (SD 3.4) ng/ml, 18.7 (SD 5.1) nmol/L and 397.5 (SD 188.4) pg/ml, respectively. The proportion of adolescents with folate, B6 and B12 intakes above the recommendation was 15.2%, 10.2%, e <1%, respectively. The foods that more contributed for folate intake were French bread (23.1%), pasta (9.7%) and beans (8.2%). For B6 intake rice (9.9%), chicken (5.7%) and meat (4.2%). For B12 intake, meat without fat (16.4%) whole milk (15%) and meat with fat (12.3%). The mean of hcy was 15.4 (SD 10.2) µmol/L in boys and 8.2 (SD 2.2) µmol/L in girls. In boys, 25% of them showed values of serum hcy concentration upper to 15 µmol/L and, means of folate and vitamin B12 decreased according of serum hcy tercil (p<0.005). Conclusions: The prevalence of inadequate intake of folate, vitamin B6 and B12 were low, possibly due to improved access and availability of food, including processed foods that contain the fortified flour with folic acid as ingredient. However, the beans, a component of the Brazilians usual dietary pattern, are founded as important contributors of folate intake. The total homocysteine levels were higher in boys when compared with girls. In boys, folate and vitamin B12 status were decreased significantly with trend among different tercile serum homocysteine concentration.
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Beauvais, Maxime. „Long term seasonality of microbial vitamin B1 and B12 metabolisms and their potential interplay in the Northwestern Mediterranean Sea“. Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS641.
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L'environnement façonne les communautés microbiennes qui dirigent les cycles biogéochimiques des océans, mais les facteurs biotiques sont également d’important déterminants dans la structure des communautés. Ces systèmes dynamiques sont composés d'espèces cooccurrentes structurées dans un réseau complexe d'interactions entre organismes et avec leur environnement. Les vitamines B1 et B12 sont des cofacteurs essentiels mais la plupart des microbes marins incluant de nombreuses espèces de phytoplancton, ne peuvent pas les produire eux-mêmes (auxotrophes aux vitamines). De plus, les vitamines B1 et B12 sont rares dans l’océan. Ensemble, ces observations soulèvent la question suivante : comment les auxotrophes assurent-ils leurs besoins en vitamines dans l’océan ? Cette question reste en grande partie sans réponse car la saisonnalité des auxotrophes et leur interaction avec les producteurs de vitamines restent peu étudiées. Pour combler ces lacunes, nous avons réalisé une série temporelle métagénomique mensuelle sur 7 ans dans un site côtier de Méditerranée Nord-Ouest (station SOLA) afin d'évaluer la saisonnalité à long terme des communautés procaryotes, en se focalisant sur les métabolismes des vitamines B1 et B12 et leur interaction potentielle au cours des saisons. Tout d'abord, nous avons mis en évidence une succession saisonnière de différents organismes pouvant utiliser des voies distinctes pour produire de la B12 tout au long de l'année. En été, les bactéries du genre HIMB11, UBA8309 et Puniceispirillum peuvent utiliser la voie de production aérobie, tandis qu'en hiver, les archées du genre Nitrosopumilus et Nitrosopelagicus peuvent utiliser la voie de production anaérobie. Ensuite, nous avons montré que lors de perturbations environnementales, les organismes habituellement porteurs de gènes de synthèse de la B12 sont remplacés par d'autres porteurs du même gène (redondance fonctionnelle), maintenant ainsi le potentiel de production de B12. Cette assurance écologique pourrait contribuer à la résilience fonctionnelle à long terme des communautés microbiennes marines exposées à des conditions environnementales interannuelles contrastées. Deuxièmement, nous avons montré que les communautés procaryotes à SOLA étaient dominées par des auxotrophes HMP (Pelagibacter), dont l'abondance était plus élevée en été avec d’autre auxotrophes plus rares (doubles HET/HMP, comme HIMB59), et par des auxotrophes B1 (HIMB11), qui étaient présents tout au long de l'année. À SOLA, nous avons rapporté une plus grande contribution des producteurs de B1 que précédemment observé dans d'autres régions, incluant des bactéries (Pseudothioglobus, MB11C04), des cyanobactéries (Synechococcus) et des archées (Nitrosopumilus). Les expériences de bio-essais ont montré de multiples périodes de limitation en vitamines et précurseurs dans l'eau de mer pendant les mois d'hiver. En outre, l'ajout de vitamines et de précurseurs a eu un impact significatif sur la structure de la communauté procaryote dans nos microcosmes, en particulier en Février. Différents ASV ont été sélectivement favorisés par différentes conditions pendant la transition hiver/printemps. Cependant, la réponse des communautés reste difficile à démêler sachant que les auxotrophes et les prototrophes sont impactés par l’ajout de vitamines/précurseurs. Enfin, grâce à l’assemblage de MAGs et en identifiant leurs potentiels de production pour la B1 et la B12, nous avons montré des schémas de cooccurrence forts et récurrents entre les auxotrophes et les producteurs de vitamines, reflétant différentes complémentarités fonctionnelles potentielles en fonction des saisons. La double complémentarité pour la B1 et la B12 était prédominante dans le réseau de cooccurrence d’été (un auxotrophe B1/B12 avec un prototrophe B1/B12), tandis que la simple complémentarité pour la B1 ou la B12 était prédominante dans les cooccurrences d'hiver (un auxotrophe B1/producteur de B12 avec un producteur de B1/auxotrophe B12)The environment shapes marine microbial assemblages that drive ocean biogeochemical cycles, but biotic interactions are also strong community structuring factors. Marine microbial communities are dynamic systems of co-occurring species structured as a complex network of interactions, including microbe to environment and microbe to microbe connections. B-vitamins are essential cofactors of critical cellular processes, and most marine microbes, including many phytoplankton species require an exogenous source of vitamins or precursors to grow (i.e., vitamin or precursor auxotrophs). Despite their ecological importance, B1 and B12 are scarce in most oceanic and coastal regions. Together, the widespread vitamin scarcity observed in oceans and the high incidence of vitamin auxotrophy raises the question of how vitamin auxotrophs ensure their vitamin requirements in a large and diluted environment? This question remains largely unanswered as the seasonality of vitamin auxotrophs and their interplay with vitamin producers remain poorly studied. To tackle these knowledge gaps, we conducted a 7 years monthly metagenomic time series in the coastal NW Mediterranean Sea (SOLA station) to assess the long-term seasonality of planktonic prokaryotic communities, with a focus on B1 and B12 metabolisms and their potential interplay over time.First, we highlighted a seasonal succession of different organisms which could use distinct biosynthesis pathways to produce B12 de-novo along the year. In summer, bacteria belonging to the genera HIMB11, UBA8309 and Puniceispirillum could use the aerobic B12 production pathway, while in winter, Thaumarchaeota belonging to Nitrosopumilus and Nitrosopelagicus genera could use the anaerobic B12 production pathway. Then, we show that during irregular environmental perturbations observed in winter at SOLA station, organisms usually carrying B12 synthesis genes are replaced by others with the same gene (i.e., functional redundancy), thus maintaining the potential for B12 production. Such ecological insurance could contribute to the long-term functional resilience of marine microbial communities exposed to contrasting inter-annual environmental conditions. Secondly, we showed that SOLA prokaryotic communities were dominated by HMP auxotrophs (Pelagibacter, AAA536-G10, Litoricola), which had higher abundances in summer together with the rarer dual HET/HMP auxotrophs (HIMB59, HIMB100, Octadecabacter), and by B1 auxotrophs (HIMB11, Puniceispirillum), which were present throughout the year. At SOLA, we reported a larger contribution of B1 producers than previously reported in other regions, including bacteria (Pseudothioglobus, MB11C04), cyanobacteria (Synechococcus, Prochlorococcus) and archaea (Nitrosopumilus, Nitrosopelagicus). Bioassays experiments using showed multiple vitamin and precursor limitations periods in SOLA seawater during winter months. Moreover, the addition of vitamins and precursors had a significant impact on prokaryotic community structure in our microcosm’s experiments, especially in February. Different ASVs were selectively promoted by different conditions during the winter/spring transition (B12, H+C and B1+B12). However, the differential response of communities remains difficult to disentangle, given that both vitamin auxotrophs and prototrophs were promoted during our incubations. Finally, by assembling high-quality metagenome assembled genomes (MAGs) and identifying their B1 and B12 lifestyles, we highlight strong and recurrent co-occurrence patterns between vitamin auxotrophs and producers reflecting different potential functional complementarities between them depending on the season. Double complementarity for B1 and for B12 was prevalent in summer co-occurrences networks (e.g., B1/B12 auxotroph co-occur with B1/B12 prototroph), while simple complementarity for B1 or B12 was prevalent in winter co-occurrences (e.g., B1 auxotroph / B12 producer co-occur with B1 producer/B12 auxotroph)
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McMahon, Jennifer A., und n/a. „The effect of homocysteine lowering vitamins on cognitive performance in older people : a randomised controlled trial“. University of Otago. Department of Human Nutrition, 2006. http://adt.otago.ac.nz./public/adt-NZDU20070426.154857.
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Background: Inverse associations have been reported between homocysteine concentrations and poor cognitive performance in several cross-sectional studies of healthy elderly subjects. Folate supplementation with or without vitamins B-12 and B-6 is an effective means of lowering homocysteine concentrations. Mood disturbances, from mild mood changes to clinical depression, are common in older populations. Several studies have shown that depressed people have lower levels of folate and vitamin B-12 and higher levels of homocysteine than non-depressed people. Improvement of mood has been reported in depressed people following supplementation with folic acid. Clinical trials are required to determine if lowering homocysteine concentration with vitamins improves cognitive function and/or mood in healthy elderly participants.
Objective: The primary aim of this research project was to carry-out a 2 year randomised, double-blind, placebo-controlled trial to determine if a supplement containing folate (1mg L-Mefolinic acid), vitamin B-12 (500(mu)g) and vitamin B-6 (10mg) improves scores or prevents decline on tests of cognition in a group of healthy older people ([greater than or equal to]̲ 65 years) with a plasma homocysteine concentration [greater than or equal to]̲13 (mu)mol/L. A second aim of this study was to determine if homocysteine lowering vitamins improved scores on tests of mood in this group.
Methods: Four hundred and sixty-five individuals, aged 65 and over, were recruited from Dunedin and surrounds, and asked to attend a screening clinic and provide a fasting blood sample. Two-hundred and seventy-six volunteers with a plasma homocysteine concentration [greater than or equal to]13(mu)mol/L were randomised to take either a combination of 1mg L-Mefolinic acid, 500(mu)g vitamin B-12 and 10mg vitamin B-6 or placebo for 2 years. A battery of cognitive tests and indices of mood was administered at baseline, one year, and two years. A fasting blood sample was collected at baseline and every six months thereafter.
Results: From baseline to 6 months of the intervention, homocysteine concentrations decreased by 37.5%, from 16.7 to 10.5 (mu)mol/L in the vitamin supplemented group and then plateaued. In the vitamin supplemented group there was a 181% increase in red blood cell folate concentration from a mean of 977 to 2752 nmol/L, and a 90.1% increase in plasma vitamin B-12 (from a mean 283 to 538 (mu)mol/L) over the study period of two years.
In the vitamin supplemented group there was a trend to poorer performance on almost all tests of cognition compared to placebo group. The vitamin group was 8% slower on Part B of the Reitan Trail Making Test, a test of speeded attention, mental tracking, visual search and mental flexibility (p=0.009). The vitamin group scored significantly lower on tests of short-term recall, Weschler Paragraphs (p=0.03) after 2 years, and the Rey Auditory Verbal Learning Test ((p=0.04) after one year, than the placebo group. There was no difference in mood score by treatment in this largely non-depressed group.
Conclusion: These results suggest a detrimental effect of high dose homocysteine lowering vitamin supplements on cognitive function in healthy older people. These results need to be confirmed in other randomised controlled trials.
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Barnabé, Aline 1982. „Avaliação da concentração de 2,3-difosfoglicerato, homocisteina plasmatica, acido folico, vitamina B12 e polimorfismos no gene da MTHFR em pacientes com doença pulmonar obstrutiva cronica“. [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/311374.
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Orientadores: Nelci Fenalti Hoehr, Joyce Annichino-BizzacchiDissertação (mestrado) - Universidade Estadual de Campinas. Faculdade de Ciencias Medicas
Made available in DSpace on 2018-08-15T09:25:16Z (GMT). No. of bitstreams: 1 Barnabe_Aline_M.pdf: 1630242 bytes, checksum: 701df85c63a84d513832abd45b2c810a (MD5) Previous issue date: 2010
Resumo: A Doença Pulmonar Obstrutiva Crônica (DPOC) é caracterizada por obstrução do fluxo aéreo que envolve um processo inflamatório crônico das vias aéreas e destruição do parênquima pulmonar induzidos pela bronquite crônica ou enfisema. Devido às anormalidades na troca gasosa que ocorre na DPOC, mudanças no pH podem alterar as concentrações de 2,3-difosfoglicerato (2,3-DPG), um fosfato orgânico presente nos eritrócitos e que exerce função importante no transporte de oxigênio. A baixa concentração de 2,3-DPG aumenta a afinidade do oxigênio à hemoglobina, dificultando sua liberação, comprometendo a oxigenação dos tecidos. Além disso, oxigenioterapia indicada para pacientes com DPOC pode levar a produção de espécies reativas de oxigênio (EROS) responsáveis pela injúria celular. Por outro lado, EROS também pode ser produzido por um aumento nos níveis de homocisteína no plasma e com isso causar lesão celular. Estudos sugerem que pacientes com DPOC podem apresentar aumento da homocisteína plasmática, um fator de risco para doenças cardiovasculares. Baseando-se nisso, o objetivo deste estudo foi avaliar os níveis de 2,3-DPG e homocisteína em pacientes com DPOC. Nossos resultados mostraram que não houve diferença na concentração de 2,3-DPG entre pacientes e controles, pois a concentração desse fosfato foi semelhante em ambos os grupos. Nos pacientes com DPOC que fazem uso ou não de oxigenioterapia também não houve diferença nas concentrações de 2,3-DPG. Portanto, o transporte e distribuição de oxigênio não estavam prejudicados nesses pacientes. No entanto, os pacientes com DPOC apresentaram hiperhomocisteinemia leve e baixos níveis de ácido fólico. Esta observação sugere a necessidade de suplementação com ácido fólico para pacientes com DPOC. Os polimorfismos C677T e A1298C no gene da MTHFR não influenciaram as concentrações de homocisteína nos pacientes com DPOC. A contribuição de nossos dados é de grande importância para o monitoramento de pacientes com DPOC.
Abstract: Chronic Obstructive Pulmonary Disease (COPD) is characterized by chronic airflow obstruction that involves a chronic inflammation of the airways and destruction of lung parenchyma induced by chronic bronchitis or emphysema. Abnormalities in gas exchange that occurs in COPD leads to changes in pH altering 2,3-DPG levels, an organic phosphate present in red blood cells and play an important role in oxygen transport. Reduced levels of 2,3-DPG increase the oxygen affinity of hemoglobin and reduces oxygen delivery, compromising tissue oxygenation. On the other hand, oxygen therapy which is used in COPD patients induces the production of reactive oxygen species (ROS) responsible for cellular injury. ROS can be also produced by an excess of homocysteine in plasma. Studies suggest that COPD patients may have increased homocysteine, a risk factor for cardiovascular diseases. The aim of the present study was to evaluate 2,3-DPG and homocysteine levels in COPD patients. Our results showed no difference in the 2,3-DPG levels between patients and controls. In patients with COPD who use oxygen therapy or not there was no difference in the 2,3-DPG. Therefore, oxygen transport and unloading were not affected. Patients with COPD had mild hyperhomocysteinemia and low levels of folic acid. This observation suggests that dietary supplement of folate to COPD patients is necessary. C677T and A1298C polymorphisms in the MTHFR gene showed no influence on concentrations of homocysteine in COPD patients. Our data make an important contribution for the monitoring of COPD patients.
Mestrado
Ciencias Biomedicas
Mestre em Ciências Médicas
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Potter, Kathleen. „The effects of long-term homocysteine-lowering treatment with folic acid, vitamin B6 and Vitamin B12 on vascular structure and function in stroke“. University of Western Australia. School of Medicine and Pharmacology, 2009. http://theses.library.uwa.edu.au/adt-WU2010.0020.
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[Truncated abstract] An elevated total plasma homocysteine concentration (tHcy) is associated with an increased risk of myocardial infarction and ischemic stroke. Folic acid, vitamin B6 and B12 supplements significantly reduce tHcy even in people who are not overtly vitamin deficient. If homocysteine is a causal risk factor for atherothrombotic events, treatment with B-vitamins might prove a simple and cost-effective means to reduce cardiovascular risk. However, it remains unclear whether elevated tHcy causes atherosclerosis or is simply a risk marker. To prove that homocysteine is a modifiable risk factor for cardiovascular disease it is necessary to show that lowering tHcy reduces vascular risk. The aim of this study was to determine whether long-term homocysteine-lowering with B-vitamins would improve vascular structure and function in people with a history of stroke. This study was a cross-sectional sub-study of the Vitamins TO Prevent Stroke trial (VITATOPS), a multi-centre, randomised, double-blind, placebo-controlled clinical trial designed to test the efficacy and safety of B-vitamins (folic acid 2mg, vitamin B6 25mg and vitamin B12 0.5mg) in the prevention of vascular events in patients with a recent history of stroke or transient ischemic attack. 173 VITATOPS participants were recruited for the current study. Age, sex, stroke type, medications, cardiovascular risk factors and smoking history were recorded and blood pressure, height, weight, waist and hip girth were measured in all subjects at least two years after randomisation. ... After a mean treatment period of 3.9 ± 0.9 years, the subjects randomised to vitamin treatment had significantly lower tHcy than the subjects randomised to placebo (7.9mol/L, 95%CI 7.5, 8.4 versus 11.8mol/L, 95%CI 10.9, 12.8; p<0.001). There were no significant differences between groups in CIMT (0.84 ± 0.17mm vitamins versus 0.83 ± 0.18mm placebo; p=0.74) or FMD (median of 4.0%, IQR 0.9, 7.2, vitamins versus 3.0%, IQR 0.6, 6.6 placebo; p=0.48). Pooled estimates from the meta-analyses showed that B-vitamin treatment reduces CIMT by 0.10mm (95%CI 0.20, -0.01mm) and increases FMD by 1.4%, (95%CI 0.7, 2.2), although these estimates may have been influenced by positive publication bias. The improvement in FMD was significant in studies of less than eight weeks duration but not in studies with longer treatment periods. The association between tHcy and CIMT and FMD was eliminated by adjustment for renal function and long-term B-vitamin treatment did not alter the strong linear relationship between tHcy and cystatin C. Lowering tHcy did not alter arterial wall inflammation assessed by 18FDG-PET, although small subject numbers meant we were unable to exclude a minor treatment effect. Long-term homocysteine-lowering with B-vitamin treatment did not improve CIMT or FMD or reduce arterial wall inflammation in people with a history of stroke. The relationship between tHcy and these markers of vascular risk was eliminated by adjustment for renal function. Our data are consistent with the hypothesis that elevated tHcy is a risk marker for cardiovascular disease rather than a modifiable causal risk factor.
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Showemimo, Opeyemi F. „Vitamin B12 Deficiency Does Not Stimulate Amyloid-beta Toxicity in a Ceanorhabditis elegans Model of Alzheimer’s Disease“. Digital Commons @ East Tennessee State University, 2021. https://dc.etsu.edu/etd/3869.
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Alzheimer’s disease (AD) is symptomized by amyloid-beta plaques in the brain and accounts for more than 65 percent of dementia cases. Vitamin B12 (cobalamin) deficiency can result in similar cognitive impairment and roughly 15% of the elderly are vitamin B12 deficient. Vitamin B12 deficiency results in the accumulation of toxic methylmalonic acid and homocysteine. Hyperhomocysteinemia is a strong risk factor for AD. To test if vitamin B12 deficiency stimulates amyloid-beta toxicity, Caenorhabditis elegans expressing amyloid-beta in muscle were fed either vitamin B12-deficient OP50-1 or vitamin B12-rich HT115(DE3) E. coli bacteria. Increased amyloid-beta toxicity was found in worms fed the 0P50-1 diet. Supplementation of the OP50-1 diet with vitamin B12 did not rescue the increased C. elegans toxicity. Knockdown of either of the only two C. elegans vitamin B12-dependent enzymes metr-1 or mmmc-1 protected against toxicity. Therefore, vitamin B12 deficiency does not stimulate Alzheimer’s amyloid-beta-mediated toxicity in C. elegans.
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Brunaud, Laurent. „Déterminants nutritionnels et génétiques de l'homocystéine et méthylation de l'ADN : modèles expérimentaux et implications en pathologie“. Nancy 1, 2003. https://hal.univ-lorraine.fr/tel-01746923.
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Shinohara, Elvira Maria Guerra. „Prevalência de anemia em gestantes de primeira consulta em centros de saúde do estado no Subdistrito de Paz do Butantã, Município de São Paulo“. Universidade de São Paulo, 1989. http://www.teses.usp.br/teses/disponiveis/9/9136/tde-27032008-142216/.
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Foram estudadas 363 gestantes de primeira consulta, que não faziam uso de medicamentos que continham ferro, ácido fólico, vitamina B12 ou associação destes, na ocasião da coleta do material, em Centros de Saúde do Estado, no Subdistrito de Paz do Butantã, município de São Paulo. A prevalência de anemia (concentração de hemoglobina inferior a 11,6 g/dl) foi de 12,4%. As médias das concentrações de hemoglobina e as prevalências de anemia, segundo o trimestre de gestação, foram respectivamente: 13,47 g/dl e 3,57% no primeiro, 12,47 g/dl e 20,86% no segundo e 12,25 g/dl e 32,14% no terceiro trimestre. Não encontramos diferença. estatisticamente significativa entre as médias das concentrações de hemoglobina e entre as prevalências de anemia nas gestantes primigestas e multigestas. O mesmo aconteceu com as médias e as prevalências das gestantes multigestas com intervalo do último parto até dois anos e maior que dois anos. Na amostra estudada, encontramos maior prevalência de anemia naquelas gestantes que pertenciam às famílias que tinham renda per capita até 0,5 SMPC (salário mínimo per capita). As prevalências de verminose e de ancilostomídeos nas 300 gestantes foram respectivamente: 64,7% e 14,0%. Nas gestantes anêmicas foram respectivamente: 73,7% e 7,9%. Nas gestantes anêmicas, a prevalência de deficiência de ferro foi de 42,2% (concentração de ferro sérico <50 µg/dl) ou 46,7% (saturação da transferrina <15% ou 40,0% (concentração de ferro sérico <50 µg/dl e saturação de transferrina <15%). A prevalência de deficiência de ácido fólico foi 44,4%. A prevalência de deficiência de ferro e ácido fólico foi de 17,8%. Não encontramos deficiência de vitamina B
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Barnabé, Aline 1982. „Prevalência das deficiências de ácido fólico, vitamina B12 e ferro em diversos grupos da população brasileira, após o programa de fortificação adotado pela ANVISA“. [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/312945.
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Orientadores: Nelci Fenalti Höehr, Joyce Maria Annichino-BizzacchiTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
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Resumo: Folato, vitamina B12 e ferro são nutrientes essenciais, cujas deficiências afetam indivíduos em todas as faixas etárias, sendo consideradas um problema de Saúde Pública no mundo. Níveis reduzidos de folato e vitamina B12 podem estar associados com níveis elevados de homocisteína (Hcy), e que eventualmente resultam em complicações. Entretanto, no Brasil, poucos estudos avaliaram a prevalência dessas deficiências, principalmente de folato e vitamina B12, após a fortificação de farinhas com ácido fólico e ferro. Os objetivos do presente estudo foram: avaliar a prevalência das deficiências de folato, vitamina B12 e ferro em idosos, crianças, gestantes e lactantes após a fortificação de farinhas com ácido fólico e ferro adotado pela ANVISA em 2004; e investigar a contribuição de polimorfismos genéticos sobre os níveis de folato, vitamina B12 e Hcy nestes indivíduos. Os indivíduos foram recrutados em Centros de Saúde da cidade de Campinas entre 2006 a 2007. No total, 719 indivíduos incluindo, 262 idosos, 106 crianças, 291 gestantes e 60 lactantes foram incluídos. As concentrações destes nutrientes foram mensuradas por eletroquimioluminescência; a dosagem de Hcy foi realizada por cromatografia líquida de alta eficiência (CLAE); e os polimorfismos foram investigados por PCR-RFLP. Os resultados mostraram que a prevalência das deficiências de folato, vitamina B12 e ferro no grupo total de indivíduos foram de 0,3%, 5,3% e 12,6%, respectivamente. Praticamente não se observou a deficiência de folato, presente apenas em um idoso e uma gestante, enquanto que a deficiência de vitamina B12 foi prevalente em gestantes (8,9%) e idosos (4,2%). Além disso, a deficiência de ferro e anemia ferropriva foram prevalentes em crianças (9,9% e 4,9%, respectivamente), e gestantes (25,1% e 5,5%, respectivamente). A hiperhomocisteinemia esteve presente principalmente em idosos (34,3%). Com relação aos polimorfismos, apenas as gestantes carreadoras dos alelos CT+TT do polimorfismo no gene MTHFR (C677T) mostraram níveis reduzidos de folato (p=0,030). Através da análise múltipla, observamos que os níveis de Hcy foram determinados principalmente pelo folato (p<0,001), vitamina B12 (p<0,001), gênero (p<0,001) e idade (p<0,001) em idosos; vitamina B12 (p= 0,011) em crianças e folato (p=0,002) em gestantes. Nossos resultados demonstraram que na população avaliada, após 2 anos do início da fortificação de farinhas com ácido fólico e ferro, a deficiência de folato é praticamente inexistente, ao contrário da deficiência de ferro e de vitamina B12. A elevada prevalência da deficiência de vitamina B12 em idosos e gestantes deve ser valorizada na prática, devido ao risco de complicações. O mesmo deve ser observado em relação à deficiência de ferro, prevalente em crianças e gestantes. Portanto, medidas como suplementação e a dosagem desses nutrientes, para grupos populacionais de risco, devem ser implementados em políticas de Saúde Pública. Além disso, a hiperhomocisteinemia observada em idosos pode ser um fator de risco ou um marcador de doença arterial, que é comum nesses indivíduos
Abstract: Folate, vitamin B-12 and iron are essential nutrients, whose deficiencies are considerable public health problems worldwide, affecting all age groups. Low levels of folato and vitamin B12 have been associated with high concentrations of homocysteine (Hcy) and can lead to complications. In Brazil, a few studies evaluated the prevalence of these nutrients, especially, folate and vitamin B12, post acid folic and iron fortification era. The aim of this study was to assess folate, vitamin B12 and iron deficiencies in distinct Brazilian populations including elderly, children, pregnant and lactating women, after the initiation of folic acid and iron fortification by Brazilian authorities. We also investigated the contribution of polymorphisms on folate, vitamin B12 and Hcy levels in these individuals. Folate, vitamin B12 and ferritin levels were measured by chemiluminescence immunoassays, and Hcy levels were determined by high-performance liquid chromatography. Genotype analyses of RFC1 A80G, GCPII C1561T and MTHFR C677T polymorphisms were performed by PCR-RFLP. The individuals were recruited from primary care centers in Campinas ¿ Brazil, between 2006 - 2007. In total 719 individuals, including elderly (262), children (106), pregnant women (291) and lactating women (60) were included. The overall prevalence of low folate, vitamin B-12 and iron status was 0.3%, 5.3% and 12.6%, respectively. Folate deficiency was practically inexistent and was observed only in elderly (n=1) and pregnant women (n=1), whereas vitamin B12 deficiency was frequent in pregnant women (8.9%) and elderly (4.2%). Moreover, iron deficiency and iron deficiency anemia were prevalent in children (9.9% and 4.9%, respectively) and pregnant women (25.1% and 5.5%, respectively). Plasma Hcy concentrations were significantly higher in the elderly (34.3%). Pregnant women carrying the MTHFR 677T allele (CT+TT) showed lower serum folate levels (p=0.030), but none of the polymorphisms investigated in this study affected folate, vitamin B12 and Hcy levels in elderly, children and lactating women. After a multivariate analysis, Hcy levels were predicted by variables such as folate (p<0.001), vitamin B12 (p<0.001), gender (p<0.001) and age (p<0.001) in elderly; vitamin B12 (p= 0.011) in children; and folate (p = 0.002) in pregnant women. Our results demonstrated that folate deficiency is practically inexistent in this population, two years after the initiation of folic acid fortification, in contrast to vitamin B12 and iron deficiency. The high prevalence of vitamin B12 deficiency in elderly and pregnant women is relevant due to health complications. Supplementation and measure of nutrients in some groups of the population should be indicated by Public Health¿s policies. Furthermore, hiperhomocysteinemia in elderly can be a risk factor or a marker of arterial disease, which is common in these individuals
Doutorado
Ciencias Biomedicas
Doutora em Ciências Médicas
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Divya, Jagasia, und Ferrando Vanesa Zanzi. „Tempeh: a tempting potential vitamin B12 treat : An exploration of legumes and vitamin B12“. Thesis, Uppsala universitet, Institutionen för kostvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-255419.
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Background: Legumes are beneficial for the environment, nutritious and coupled with various health benefits. However, they lack the essential vitamin B12 and a vitamin B12 deficiency can lead to hazardous health problems. Tempeh is a fermented legume product that has the potential of carrying vitamin B12. Aim: The aim of this thesis is to investigate consumers' awareness of vitamin B12 and explore the indications for the possibility to introduce tempeh - a fermented legume product. Method: A quantitative survey was carried out within four different areas of Stockholm using a clustering sample technique with 195 participants who were recruited outside supermarkets through convenience sampling. Results: The majority of the subjects had moderate consumption of legumes and was open to trying tempeh even though they had never heard about it. While their knowledge of vitamin B12 was limited, the biggest risk groups, vegans and the elderly, were aware that they were a risk group but only a minority of them knew the correct vitamin B12 food sources. Conclusion: The participants in this study had little knowledge about vitamin B12 food sources, deficiencies or risk groups. Since their legume consumption was regular and they were positive towards trying tempeh even though they had never heard about tempeh before, there is potential for it in the market. However, more studies are needed to research the bioavailability of vitamin B12 in tempeh even though new research gives hope that it can be a possibility.
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Almeida, Lana Carneiro. „Preditores dietéticos das concentrações séricas ou plasmáticas de homocisteína, ácido fólico, vitaminas B12 e B6 em mulheres“. Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/6/6133/tde-25062007-175008/.
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Objetivo Examinar a correlação entre fatores dietéticos, obtidos por questionário de freqüência alimentar (QFA) validado, e concentrações séricas ou plasmáticas de homocisteína (hcy), ácido fólico, vitaminas B12 e B6 em mulheres de São Paulo. População e métodos Foram analisados os dados dietéticos de 1.434 mulheres de 21 a 65 anos de um estudo caso-controle sobre consumo alimentar e lesões neoplásicas do colo uterino realizado em três hospitais públicos da cidade de São Paulo, excluindo-se os casos de câncer invasivo. Todas participantes tiveram sua ingestão alimentar usual avaliada por entrevista, usando um QFA, e forneceram amostras sangüíneas em jejum para separação de plasma e soro. Concentrações séricas de ácido fólico e vitamina B12 séricos foram analisadas por técnica de fluoroimunoensaio, enquanto concentrações plasmáticas de hcy e vitamina B6 foram analisadas por Cromatografia Líquida de Alta Performance em fase reversa. Correlações entre ingestão estimada de nutrientes, ajustados pelas calorias totais, e alimentos com as variáveis bioquímicas foram avaliadas em modelos de regressão linear múltiplos, após ajuste para co-variáveis, tais como idade, Índice de Massa Corporal (IMC), estilo de vida (incluindo tabagismo), morbidade ginecológica pregressa ou atual, história obstétrica e uso de anticoncepcional oral. Resultados Embora apenas 6,2% das participantes do estudo tenham apresentado concentrações séricas de ácido fólico abaixo do valor de referência (7 nmol/L), 45,7% e em 97,1% tiveram um consumo estimado de folato inferior a 180 ug/dia e 400 ug/dia, respectivamente. Modelos de regressão múltiplos mostraram correlação positiva entre ácido fólico sérico e ingestão estimada de proteína, ferro, folato, vitaminas B1, B3, B6, A, C e frutas/sucos cítricos e de vegetais verdes, e correlação inversa entre ácido fólico sérico e consumo estimado de gorduras, doces e leite e derivados. Resultados similares foram obtidos após ajuste adicional para fibra da dieta, exceto com consumo de folato e de vegetais verdes, que perderam a significância estatística como preditores independentes das concentrações séricas de ácido fólico. Concentrações séricas de vitamina B12 abaixo do ponto de corte de 148 pmol/L foram observadas em 11,0% da amostra; a maioria delas (70,4%) apresentou ingestão estimada de vitamina B12 igual ou superior à recomendação (2 ug/dia). As concentrações séricas de vitamina B12 foram positivamente correlacionadas com consumo estimado de produtos lácteos e das vitaminas B2 e B12. A ingestão de fibra, vitamina E e leguminosas foi inversamente correlacionada com as concentrações séricas de vitamina B12. Ingestão de vitamina B6 abaixo das recomendações de 1,3 mg/dia (≤50 anos) e 1,5 mg/dia (>50 anos) foi observada em 49% das participantes. Nenhuma correlação foi encontrada entre dados da dieta e concentrações plasmáticas de vitamina B6. As concentrações plasmáticas de hcy foram positivamente correlacionadas com o consumo estimado de carboidratos e doces, e inversamente correlacionadas com o consumo estimado de proteína, colesterol, ferro, zinco de origem animal, vitaminas A, B2, B12 e B6, e pescados. Entretanto, essas correlações perderam a significância após ajuste adicional por proteína da dieta, um dos mais fortes preditores das concentrações plasmáticas de hcy. Conclusão Nutrientes e alimentos selecionados da dieta mostraram-se preditores independentes das concentrações séricas de ácido fólico e de vitamina B12, indicando as principais fontes alimentares desses nutrientes nesta população e em outras similares. A forte correlação negativa entre concentração plasmática de Hcy e proteína da dieta sugere base para o planejamento de futuras intervenções nutricionais. Nenhuma correlação foi observada entre concentração plasmática de vitamina B6 e fatores dietéticos estimados.Objective To examine whether measurements of dietary intakes, obtained with a validated quantitative food frequency questionnaire (FFQ), correlated with serum or plasma levels of folic acid, vitamins B12 and B6 and homocystein (hcy) measured in low-income women living in São Paulo, Brazil. Population and methods We analyzed dietary data from 1434 women aged 21-65 years enrolled in a case-control study of diet and cervical cancer carried out in three public hospitals of São Paulo. Data for women with invasive cervical cancer were excluded. All participants had their usual dietary intake assessed by interview, using a validated FFQ, and provided a fasting blood sample for serum and plasma separation. Serum concentrations of folic acid and vitamin B12 were measured by fluorimmunoassay, while serum levels of vitamin B6 and plasma levels of hcy were measured by reversed-phase high performance liquid chromatography. Correlations between estimates of food and energy-adjusted nutrient intakes and levels of folic acid, vitamins B12 and B6 and hcy were assessed using multiple linear regression models, adjusted for covariates such as age, body mass index, lifestyle (including smoking), past and current gynecologic morbidity and obstetric history, and use of oral contraceptives. Results Although only 6.2% of the study participants had serum folic acid levels below the reference value of 7 nmol/L, 45.7% and 97.1% had a dietary intake of folic acid estimated to be less than 180 g/day and 400 g/day, respectively. Multiple linear models showed serum folic acid levels to be positively correlated with the estimated intake of protein, iron, folate, vitamins B1, B3, B6, A and C, citrus fruits and juices and green vegetables, and negatively correlated with the estimated intake of fat, sweets and dairy products. Similar results were obtained after a further adjustment for fiber intake in the model, except for the estimated intake of folic acid and green vegetables, which lost their statistical significance as independent predictors of serum folic acid levels. Serum levels of vitamin B12 below the cut-off point of 148 pmol/L were found in 11.0% of study participants; most of them (70.4%) had their vitamin B12 intake estimated to be equal or greater than the reference value of 2 g/day. Serum levels of vitamin B12 were positively correlated with the estimated intake of dairy products and vitamins B2 and B12. The estimated intakes of fiber, vitamin E and beans were negatively correlated with serum levels of vitamin B12. Dietary vitamin B6 was estimated to be below the recommended levels of 1.3 mg/day (age 50 years) or 1.5 mg/day (age > 50 years) in 49.0% of study participants. No correlation was found between estimated intakes of foods and nutrients and plasma levels of vitamin B6. Hcy concentrations were positively correlated with the estimated intake of carbohydrates and sweets, and negatively correlated with the estimated intake of protein, cholesterol, iron, zinc of animal origin, vitamins A, B2, B12 and B6 and fishes. However, these correlations were no longer significant after additional adjustment for dietary protein, the strongest predictor of hcy plasma levels. Conclusion The estimated dietary intakes of selected foods and nutrients were shown to be independent predictors of measured serum levels of folic acid and vitamin B12, providing a basis for indentifying the main dietary sources of these nutrients in this and similar populations. The strong negative correlation between plasma levels of hcy and dietary protein provides a basis for future nutritional interventions. No correlation was found between plasma concentrations of vitamin B6 and estimated dietary intakes.
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Scaramele, Natália Francisco. „Expressão de microRNAs no hipocampo de ratos submetidos a meningite pneumocócica e tratados com vitamina B12 /“. Araçatuba, 2019. http://hdl.handle.net/11449/182271.
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Orientador: Flávia Lombardi LopesResumo: A meningite se caracteriza pela inflamação da aracnóide, pia-máter e líquor; causando danos às estruturas corticais e subcorticais. As meningites bacterianas estão intimamente relacionadas ao nível de desenvolvimento socioeconômico do país e são consideradas endêmicas no Brasil. Apesar dos esforços para o desenvolvimento de medicamentos e vacinas, a doença ainda possui altos índices de morbidade. Ela ocorre quando bactérias atravessam barreiras de proteção do corpo e alcançam o sistema nervoso central, desencadeando uma resposta imunológica. Sabe-se que durante o curso da doença os níveis de homocisteína do líquor aumentam, promovendo desmielinização e danos neuronais, e que a vitamina B12 é um tratamento utilizado para diminuir danos. Os microRNAs (miRNAs) são instrumentos de resposta fisiológica, tendo sua expressão modificada em diferentes tecidos, em decorrência de diferentes estímulos fisiológicos e patológicos. Estão associados ao controle da expressão de diferentes mediadores inflamatórios e sua ausência é capaz de causar danos severos a resposta imune. Considerando a importância dos miRNAs para regulação de processos imunes o presente estudo visou elucidar os padrões de expressão dos miRNAs durante o processo inflamatório da meningite pneumocócica (MP), bem como observar esses padrões em resposta ao tratamento adjuvante da doença com vitamina B12. Observamos um total de 37 miRNAs diferencialmente expressos, a infecção regulou positivamente 22 deles, e outros 7 negativ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Meningitis is characterized by an arachnoid, pia mater and cerebrospinal fluid inflammation; causing damage to the cortical and subcortical structures. Bacterial meningitis is closely related to the level of socioeconomic development of country and is considered endemic in Brazil. Despite efforts to develop drugs and vaccines, the disease still has high rates of morbidity and mortality. Occurring when bacteria cross body protection barriers and reach the central nervous system, triggering immune response. It is known that during disease course the the levels of homocysteine increase in cerebrospinal fluid, leading to demyelination and neuronal damage, and that vitamin B12 is a treatment used to reduce those damages. MicroRNAs (miRNAs) are instruments of physiological response, having their expression modified in different tissues, due to different physiological and pathological stimuli. They are associated with expression control of different inflammatory mediators and their absence is capable of causing severe damage to the immune response. Considering the importance of miRNAs in regulation of immune processes, the present study aimed to elucidate miRNA expression patterns during the inflammatory process resulting from pneumococcal meningitis (PM), and to observe these patterns in response to adjuvant treatment of vitamin B12 in infected rats. We observed a total of 37 differentially expressed miRNAs; the infection positively regulated 22 and negatively regulated 7 of them, ... (Complete abstract click electronic access below)
Mestre
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Zant, Ayman [Verfasser], und Rima [Akademischer Betreuer] Obeid. „Auswirkung einer mit Vitamin B12 angereicherten Zahncreme auf Plasma-Vitamin-B12 / Ayman Zant ; Betreuer: Rima Obeid“. Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2019. http://d-nb.info/1213294606/34.
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Murray, Louise M. „Comparative study of vitamin B12 and holotranscobalamin or active B12 as a marker for vitamin B12 deficiency at Dr George Mukhari Hospital“. Thesis, University of Limpopo (Medunsa Campus), 2012. http://hdl.handle.net/10386/774.
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Thesis (M Med (Chemical Pathology)) -- University of Limpopo, 2012.Abstract Aim: This study was undertaken to compare the diagnostic sensitivity and specificity of total vitamin B 12 analyses to active B 12 (holoTC) analyses in a population of patients attending the Dr George Mukhari Hospital in Pretoria. Methods: Routine serum folate, full blood count (FBC), thyroid function test, homocysteine, serum total vitamin B 12 and active B 12 analyses were performed on 30 samples. Results: Serum folate was determined in all patients and 96% of the patients had a normal folate value. When looking at the FBC results it is important to note that three times as many males as females presented with anemia (36% versus 16%). Thyroid function tests were normal in 90% of patients. When the total vitamin B 12 test was preformed only 10% of patients tested positive for vitamin B 12 deficiency, in contrast to the active B12 analyses where 16% of patients tested positive for vitamin B12 deficiency. Both tests had a diagnostic sensitivity of 50%. The diagnostic specificity for total vitamin B12 was 93% in comparison with the 86% obtained by the active B12 analyses; when homocysteine was used as the true marker for vitamin B12 deficiency. Conclusion: Diagnostic sensitivity was the same and the total vitamin B12 test's specificity was better in comparison to the active B 12 analyses. Thus the active B 12 assay cannot be recommended for routine use, since it has no benefit.
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Chen, Hong-chei. „Studies on the biosynthesis of vitamin B2 and vitamin B12 /“. The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487596307358381.
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Aguiar, Marise dos Santos. „Níveis séricos de vitamina B12, folato e homocisteína em pacientes dispépticos funcionais após um ano da erradicação do Helicobacter Pylori“. reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/118629.
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Introdução: Dispepsia funcional é uma doença que possui critérios diagnósticos definidos por reuniões de consenso, conhecidos por critérios de Roma. Apresenta alta prevalência mundial, grande impacto social e redução na qualidade de vida do indivíduo. Helicobacter pylori está envolvida na patogênese da dispepsia funcional, sendo indicada sua detecção e erradicação no tratamento dos pacientes dispépticos funcionais. H. pylori também tem sido sugerida como um importante agente na etiologia de níveis baixos de Vitamina B12 no soro. A hiperhomocisteinemia secundária à deficiência de Vitamina B12 e folato podem constituir um risco para as doenças cardiovasculares. Objetivo: investigar a relação entre os níveis séricos de Vitamina B12, folato e homocisteína e infecção pelo H. pylori em pacientes dispépticos funcionais. Métodos: Foram incluídos pacientes dispépticos funcionais, pelos critérios de Roma III do estudo HEROES (Helicobacter Eradication Relief of Dyspeptic Symptoms) - ClinicalTrials.gov número NCT00404534. Os pacientes dispépticos que apresentaram positividade para H. pylori foram randomizados para erradicação da bactéria com antibiticoterapia oral ou placebo. Após doze meses realizaram o segundo exame endoscópico com mesma metodologia. Da amostra total, 77 continuaram positivos para a infecação por H. pylori e 77 tiveram como resultado a erradicação da bactéria H. pylori, ou seja, negativaram. O material biológico foi previamente coletado e armazenado, além dos respectivos dados demográficos e clínicos. As amostras foram armazenadas a -80◦C em ependorf e realizadas medidas em soro dos níveis de vitamina B12 e folato e homocisteína. Resultados: Da amostra total, 77 pacientes eram H. pylori positivo (15 homens e 62 mulheres) e 77 eram H.pylori erradicados (21 homens e 56 mulheres). A média de idade foi de 47,8±11,5, em relação à idade e gênero não houve diferença significativa entre os grupos (p > 0,05). Quanto aos resultados reunidos em categorias (níveis de vitamina B12, folato e homocisteína), conforme os pontos de corte usados na literatura, não foi observada diferença estatisticamente significativa entre os dois grupos de pacientes (p > 0,6). Não houve correlação entre idade e níveis de vitamina B12 (p = 0,924). Houve diferença entre gêneros para homocisteína (p = 0,035), porém não houve significância para vitamina B12 (p = 0,584) e folato (p = 0,312). Não houve diferença entre níveis de homocisteína de pacientes H. pylori positivos e H. pylori erradicados para ambos os gêneros (p > 0,5). Conclusões: O presente estudo demonstrou que não houve relação significativa entre os níveis séricos de Vitamina B12, folato e homocisteína e infecção por H. pylori em relação aos H. pylori erradicados nos dispépticos funcionais. E quanto aos níveis de homocisteína comparados entre gêneros, os valores foram mais altos em homens.Introduction: Functional dyspepsia a disease which has diagnosis criteria defined by consensus gatherings, known as the Rome criteria. It is highly prevalent worldwide, has great social impact, and reduces the quality of life of individuals. Helicobacter pylori is involved in the pathogenesis of functional dyspepsia, and its detection and eradication are indicated in the treatment of functional dyspepsia patients. H. pylori has also been suggested as an important agent in the etiology of low levels of vitamin B12 in serum. A hyperhomocysteinemia secondary to vitamin B12 and folate deficiencies could pose a risk for cardiovascular diseases. Objective: To investigate the relationship among the serum levels of Vitamin B12, folate and homocysteine, and the H. pylori infection in functional dyspeptic patients. Methodology: A group of patients with functional dyspepsia was included, following the Rome III criteria from the study HEROES (Helicobacter Eradication Relief of Dyspeptic Symptoms) – ClinicalTrials.gov number NCT00404534. The dyspeptic patients who were positive for H. pylori in tissue biopsy were randomized to eradication of the bacteria with oral antibiotic therapy or placebo. After twelve months, a second endoscopy was performed with the same methodology. Of the total sample, 77 patients remained positive for H. pylori and 77 patients had as a result the eradication of H. pylori bacteria, that is, they became negative. The biological material was previously collected and stored, besides its demographic and clinical data. The samples were stored at -80◦C in Eppendorf, they were measured in the serum of vitamin B12 folate and homocysteine levels. Results: Of the total sample, 77 patients were positive for H. pylori (15 men, 62 women) and 77 patients had the eradication of H. pylori (21 men, 56 women). The average age of the sample was about 47,8±11,5,regarding age and gender, it was not observed significant difference between the groups (p > 0,05). Concerning the results gathered into categories (the levels of vitamin B12, folate, and homocysteine), as the cut off points used in the literature, it was not observed statistically significant difference between the two groups of patients (p > 0,6). There was no correlation between age and vitamin B12 levels (p = 0,924). There was difference between genders for homocysteine (p = 0,035), but there was no significant difference for vitamin B12 (p = 0,584) and folate (p = 0,312). There was no difference between homocysteine levels of positive patients for H. pylori and H. pylori eradication in both genders (p > 0.5). Conclusions: The study showed no significant relationship between the serum levels of vitamin B12, folate, and homocysteine and the H. pylori infection in relation to H. pylori eradication in functional dyspeptic patients. Regarding homocysteine levels compared between genders, the values were higher in men.
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Antunes, Marcelo Moreira. „Estratégias farmacêuticas com fósforo orgânico e vitamina B12 para melhorar a funcionalidade hepática de vacas leiteiras primíparas após o parto“. Universidade Federal de Pelotas, 2015. http://repositorio.ufpel.edu.br:8080/handle/prefix/3697.
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O objetivo deste estudo foi avaliar os efeitos da aplicação de fósforo orgânico (butafosfan) e vitamina B12 (cianocobalamina) sobre marcadores do metabolismo energético, mineral e inflamatório, produção de leite e sobre o índice de funcionalidade hepática de vacas leiteiras primíparas. Vinte e três vacas da raça Holandês foram aleatoriamente separadas em três grupos experimentais: Catosal (CAT, n = 8), que receberam total de 100 mL de Catosal®; Butafosfan (BUT, n = 8), que receberam total de 100 mL de solução aquosa de Butafosfan; e Controle (CTL, n = 7), que receberam total de 100 mL de solução fisiológica 0,9%. Todos os animais receberam os 100 mL divididos em 5 aplicações de 20 mL, em intervalos de 24 horas, por via subcutânea, iniciando logo após o parto. Os animais do grupo BUT apresentaram menores concentrações (P<0,05) de beta hidroxibutirato que os animais do grupo CTL. Os demais parâmetros metabólicos, o escore de condição corporal e a produção de leite não foram influenciados pelos tratamentos (P>0,05). O índice de funcionalidade hepática não foi influenciado pelos tratamentos (P>0,05). Após a separação dos animais em grupos de alto e baixo índice de função hepática, os animais do grupo com melhor função hepática (alto) apresentaram menores concentrações de beta hidroxibutirato (P<0,05) e tendência de menores concentrações de ácidos graxos não esterificados (P<0,10), enquanto que os animais com pior função hepática (baixo) apresentaram tendência de menores concentrações de albumina (P<0,10). Em conclusão, neste estudo o índice de funcionalidade hepática não foi influenciado pelos tratamentos.
The objective of this study was to evaluate the effects of organic phosphorus (butafosfan) and vitamin B12 (cyanocobalamin) on markers of energy, mineral and inflammatory metabolism, milk production and the liver functionality index of primiparous dairy cows. Twenty-three Holstein dairy cows were randomly allocated into three groups: Catosal (CAT, n = 8), receiving total of 100 mL of Catosal®; Butafosfan (BUT, n = 8) that received a total of 100 mL of aqueous Butafosfan; and Control (CTL, n = 7), receiving total of 100 mL of 0.9% saline. All the animals received the 100 mL divided in five 20 mL applications at 24-hour intervals, subcutaneously, beginning soon after birth. The animals in the group BUT showed lower beta-hydroxybutyrate concentrations (P<0.05) than animals in the CTL group. The other metabolic parameters, body condition score and milk production were not affected by treatments (P>0.05). The liver functionality index was not affected by treatments (P> 0.05). After the separation of the animals in groups of high and low index of liver function, the animals of the group with better liver function (high) had lower concentrations of beta-hydroxybutyrate (P<0.05) and a trend of lower concentrations of non-esterified fatty acids (P<0.10), whereas the animals with poor liver function (low) showed a tendency to have lower concentrations of albumin (P <0.10). In conclusion, in this study the liver functionality index was not affected by treatments.
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Heilmann, Romy Monika, Niels Grützner, Christina M. Iazbik, Rosana Lopes, Seth C. Bridges, Jan S. Suchodolski, Guilermo C. Couto und Jörg M. Steiner. „Hyperhomocysteinemia in greyhounds and its association with hypofolatemia and other clinicopathologic variables“. Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-213902.
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Background: Folate and cobalamin are essential cofactors for homocysteine (HCY) metabolism. Hyperhomocysteinemia, a multifactorial condition, may reflect B vitamin deficiency and is associated with increased risk of cardiovascular disease, thrombosis, and neurodegenerative and chronic gastrointestinal diseases in humans. Hyperhomocysteinemia has been reported in Greyhounds with suspected chronic enteropathy. Objectives: To evaluate the frequencies of and the association between hypofolatemia and hyperhomocysteinemia in Greyhounds. Animals: Data and serum samples from 559 Greyhounds. Methods: Nested case-control study. The frequency of hypofolatemia in Greyhounds was determined by a laboratory database search. The relationship between hyperhomocysteinemia (measured by gas chromatography-mass spectrometry) and hypocobalaminemia and hypofolatemia was evaluated, and its frequency compared between healthy Greyhounds and Greyhounds with thrombosis or chronic diarrhea. Results: Hypofolatemia was identified in 172 of 423 (41%) Greyhounds and was more common in hypo- than in normocobalaminemic dogs (49% vs. 35%; P = .0064). Hyperhomocysteinemia was detected in 53 of 78 (68%) of Greyhounds, being more common in hypo- than in normofolatemic dogs (88% vs. 59%; P = .0175). All healthy Greyhounds, 21 of 30 (70%) of dogs with chronic diarrhea and 6 of 8 (75%) of those with thrombosis, were hyperhomocysteinemic. Serum HCY concentrations were inversely correlated with serum folate concentration (q = -0.28; P = .0386) and were positively associated with
serum albumin concentration (q = 0.66; P = .0022). Conclusions and Clinical Relevance: Hyperhomocysteinemia occurs frequently in the Greyhound population. Its association with hypofolatemia suggests decreased intracellular availability of B vitamins, but the functional implications warrant further investigation. Hyperhomocysteinemia in Greyhounds potentially may serve as a spontaneous canine model to further investigate hyperhomocysteinemia in humans.
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McGoldrick, Helen Margaret. „Cobalamin (vitamin B12) biosynthesis in rhodobacter capsulatus“. Thesis, Queen Mary, University of London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415432.
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Martens, Jan-Henning. „Gezielte Entwicklung von Bacillus megaterium für biotechnologische Anwendungen“. [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=96717869X.
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Batailler, Karine. „Carence en vitamine B12 en médecine interne gériatrique“. Bordeaux 2, 1995. http://www.theses.fr/1995BOR2M156.
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Andrade, Renato Allan Navarro. „Um luminômetro Fluxo-Batelada para Determinação de Vitamina B12 em Medicamentos“. Universidade Federal da Paraíba, 2011. http://tede.biblioteca.ufpb.br:8080/handle/tede/7057.
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Previous issue date: 2011-11-11Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
In this work was developed a luminometer for analysis by chemiluminescence, coupled to a flow-batch analysis automatic system. The performance of the developed instrument was evaluated by means of the determination of vitamin B12 in pharmaceutical formulations. The chemical principle is based on the catalytic effect of cobalt (II) ion over luminol oxidation by hydrogen peroxide in alkaline medium whose reaction product emits electromagnetic radiation in visible region (more precisely at 425 nm). The detection system of the developed instrument consisted of a silicon photodiode and a module for amplification of analytical signals. The univariate calibration model was validated by means of Analysis of Variance (ANOVA) and used later in the quantification of vitamin B12 in real samples. The limits of detection and quantification obtained were 0.11 and 0.36 μg L-1 of vitamin B12. The analytical frequency was estimated in 90 samples h-1. The accuracy of the proposed instrument was attested by means of recovery tests whose obtained recovery rates were between 98 and 102%. The proposed instrument yielded results with satisfactory precision, as revealed by low value of overall standard deviation. Such results demonstrated that is possible to quantify vitamin B12 employing a simple, economic and robust method which generate low amount of waste to the environment.
Neste trabalho foi desenvolvido um luminômetro para análise por quimiluminescência, acoplado a um sistema automático de análise em fluxo-batelada. O desempenho do instrumento desenvolvido foi avaliado por meio da determinação de vitamina B12 em medicamentos. O princípio químico do sistema baseia-se no efeito catalítico do íon cobalto (II) sobre a oxidação do luminol pelo peróxido de hidrogênio em meio alcalino cujo produto da reação emite radiação eletromagnética na região visível (mais precisamente em 425 nm). O sistema de detecção do instrumento desenvolvido consiste de um fotodiodo de silício e de um módulo para amplificação dos sinais analíticos. O modelo de calibração univariado foi validado por meio da Análise de Variância (ANOVA) e usado posteriormente na quantificação de vitamina B12 em amostras reais. Os limites de detecção e quantificação obtidos foram 0,11 e 0,36 μg L-1 de vitamina B12. A frequência analítica foi estimada em 90 amostras h-1. A exatidão do instrumento proposto foi atestada por meio de testes de recuperação cujas taxas obtidas foram entre 98 e 102%. O instrumento proposto forneceu resultados com precisão satisfatória, como revelado pelo baixo valor de desvio padrão conjunto. Tais resultados obtidos demonstram que é possível quantificar vitamina B12 utilizando um método simples, econômico, robusto e que produz baixa quantidade de resíduos para o meio ambiente.
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Kowalzik, Frank. „Prophylaxe der Frühgeborenenanämie mittels Vitamin B12 und Folsäure“. [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=968791905.
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Aydın, Osman Sarıtaş Ülkü. „Helicobacter pylori eradikasyonunun vitamin B12 eksikliği üzerine etkisi /“. Isparta: SDÜ Tıp Fakültesi, 2006. http://tez.sdu.edu.tr/Tezler/TT00284.pdf.
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Vogiatzoglou, Anna. „Vitamin B12 status : determinants, biomarkers and brain function“. Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526422.
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Borley, Mark Letchford. „The uptake of vitamin B12 by unicellular algae“. Thesis, Royal Holloway, University of London, 1987. http://repository.royalholloway.ac.uk/items/e6b0cd50-d50c-45ee-a723-bcf53e5d0125/1/.
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Vitamin B12 binding and uptake by two unicellular, marine algae, the autotrophic Dunaliella primolecta and the auxotrophic Pavlova lutheri, has been studied. Features of the extracellular binders found in the culture medium of micro-algae were examined to elucidate their role. The B12 binding capacity of these proteins was shown to be proportional to cell density, and they were relatively stable for at least one month. Nevertheless, cells bind the majority of vitamin until stationary phase. Membrane-bound and intracellular cytosolic binders have also been isolated, representing around 49 and 16 % respectively of the total B12 binding capacity of cultures, 35% typically being associated with the extracellular fraction. To discover the relationship between these proteins and the nature of the uptake process, characterisation was pursued. An affinity chromatography-based purification scheme was developed for the binders, and small quantities of these proteins were purified from all three phases. Gel filtration showed uniform molecular weights in excess of 500,000, and amino acid analyses revealed similar compositions. The identification of carbohydrate components was investigated using a lectin-binding assay. However, it was not found to be possible to determine sub-unit molecular weight by SDS gelelectrophoresis, and attempts at localisation of the cellular B12 binding sites using fluorescence microscopy and electron probe micro-analysis were unsuccessful. Interestingly though, similar vitaminbinding characteristics were demonstrated for isolatedchloroplasts and intact cells of D. primolecta. Aspects of B12 and its uptake by micro-algae arereviewed, and an explanation for extracellular B12 binding proteins involving non-specific release issuggested. A general model of two-stage uptake of the vitamin by micro-algae, with a primary stage of binding to a receptor protein in the plasma membrane and a secondary phase of energy-dependent internalisation, is also proposed.
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Stanislava, Nikolić. „Uticaj metformina na nastanak deficita vitamina B12 kod pacijenata sa tipom 2 dijabetes melitusa“. Phd thesis, Univerzitet u Novom Sadu, Medicinski fakultet u Novom Sadu, 2019. https://www.cris.uns.ac.rs/record.jsf?recordId=110042&source=NDLTD&language=en.
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Prema podacima iz 2011 godine, u Srbiji je približno 630 000 ljudi (8,6%) obolelo od dijabetes melitus-a, a procenjuje se da će taj broj porasti na 730 000 (10,2%) do 2030 godine. Preko 90% obolelih ima tip 2 dijabetes melitus (T2DM). Prva linija medikamentne terapije predstavljaju bigvanidi čiji je najznačajniji predstavnik metformin. Prema literaturnim podacima, u oko 10-30% sluĉajeva, kontinuirana upotreba metformina ima za posledicu smanjenu intestinalnu apsorpciju vitamina B12. Tačan patofiziološki mehanizam koji dovodi do metforminom indukovane malapsorpcije vitamina B12 nije u potpunosti ispitan i poznat i postoji nekoliko aktuelnih teorija s ciljem objašnjenja ovog kompleksnog problema. Cilj rada je bio utvrđivanje nivoa, dinamike, trenda i učestalosti promena vitamina B12, holotranskobalamina (B12 aktiv), homocisteina i folne kiseline tokom kontinuirane primene metformina tokom godinu dana. Studija praćenja je sprovedena u Centru za laboratorijsku medicinu a u saradnji sa Klinikom za endokrinologiju, dijabetes i bolesti metabolizma, Kliničkog centra Vojvodine. Ovom studijom je obuhvaćeno 50 ispitanika obolelih od T2DM a u momentu uvođenja metformina. Svim ispitanicima je određivana koncentracija vitamina B12, B12 aktiva, homocisteina i folne kiseline, u momentu uvođenja terapije kao i nakon 4, 8 i 12 meseci primene metformina. Za dvanaest meseci kontinuirane primene metformina, utvrđen je kontinuirani pad i redukcija vrednosti ukupnog vitamina B12 za 25.29 %, odnosno vrednosti B12 aktiva za 23.26 %. U toku ispitivanja, utvrđen je kontinuirani trend porasta vrednosti homocisteina u krvi, s statistički značajnim porastom vrednosti homocisteina nakon osam meseci primene metformina. Pošavši od predpostavki da metformin istovremeno blokira apsorpciju vitamina B12 u gastrointestinalnom traktu kao i raspoloživost iz postojećih, tkivnih rezervi, zatečene količine ovog vitamina u ciljnim ćelijama se postepeno redukuju i troše, rezultujući krajnjem snižavanju nivoa metabolički aktivnih oblika kobalamina, te posledičnoj akumulaciji homocisteina kako u ćelijskom, tako i u vanćelijskom prostoru. Na osnovu dobijenih rezultata ispitivanja može se predložiti opservacija nivoa ukupnog vitamina B12 i homocisteina u krvi pre uvođenja metformina u terapiju tipa 2 dijabetes melitusa kao i dvanaest meseci nakon toga. Na osnovu nivoa jednogodišnjeg pada koncentracija ukupnog vitamina B12, porasta koncentracija homocisteina, kao i drugih kliničkih i laboratorijskih parametara, može se razmatrati opcija uvođenja supstitucione terapije vitaminom B12 ili dalja opservacija nivoa vitamin B12 u krvi i ćelijskom prostoru.According to data from 2011, in Serbia, approximately 630.000 people (8.6%) were diagnosed with diabetes mellitus, and it is estimated that this number will increase to 730.000 (10.2%) by 2030. Over 90% are type 2 diabetes mellitus (T2DM) patients. The first line of medication therapy is metformin. According to the literature data, in about 10-30% of cases, continuous use of metformin causes impared intestinal absorption of vitamin B12. The exact pathophysiological mechanism leading to metformin induced malabsorption of vitamin B12 has not been fully known, and there are several current theories to explain this complex problem. The aim of this study was to determine the level, dynamics, trend and frequency of changes in blood levels of total vitamin B12, holotranscobalamin (B12 active), homocysteine and folic acid during continuous application of metformin, over a year. The study was carried out at the Center of Laboratory Medicine in cooperation with the Clinic for Endocrinology, Diabetes and Metabolic Diseases, Clinical Center of Vojvodina. This study included 50 T2DM patients at the time of the introduction of metformin therapy. Levels of vitamin B12, holotranscobalamin, homocysteine and folic acid are determined before and after 4, 8 and 12 months of metformin administration, to all subjects. After a year of metformin use, the level of total vitamin B12 has been reduced by 25.29%, as well as holotranskobalamin by 23.26%. During the study, a continuous elevation of homocysteine levels was determined, with statistically significant increase in homocysteine values after eight months of metformin administration. Starting from the assumption that metformin blocks the absorption of vitamin B12 in the gastrointestinal tract as well as the availability of existing tissue reserves, the amount of this vitamin in the target cells is gradually reduced, resulting in an extremely low level of metabolically active forms of this vitamin and the consequent accumulation of homocysteine in intracellular and extracellular space. On the basis of the obtained test results, it may suggest observation of the level of total vitamin B12 and homocysteine prior to the introduction of metformin in T2DM therapy and after one year thereafter. Based on the level of one-year decline of total vitamin B12 and the increase of homocysteine concentrations, as well as other clinical and laboratory parameters, substitution therapy with vitamin B12 or further monitoring of laboratory parameters of vitamin B12 metabolism may be proposed.
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Leal, Renato Santos. „Associação de polimorfismos nos genes da metilenotetrahidrofolatoredutase, metionina sintase, cistationina beta-sintetase e micronutrientesrelacionados à via metabólica da homocisteína em mães e recém-nascidos do Estado da Bahia“. reponame:Repositório Institucional da FIOCRUZ, 2008. https://www.arca.fiocruz.br/handle/icict/4267.
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Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, Bahia, Brasil
Níveis elevados de homocisteína (Hcy) no plasma têm sido associados à presença de polimorfismo no gene da Metilenotetrahidrofolato Redutase (MTHFR), Metionina Sintase (MS) e Cistationina beta Sintetase (CBS) ou relacionados com quadros nutricionais, que podem alterar uma das duas vias metabólicas que envolvem os precursores do metabolismo da Hcy, remetilação ou trans-sulfuração. Desta forma, os polimorfismos gênicos associados ao metabolismo da vitamina B12, folato podem conferir níveis elevados de homocisteína, assim como diminuição nos níveis de folato e vitamina B12 plasmático, produzindo complicações durante a gravidez bem como, alterações na metilação do DNA e conseqüentemente evoluir para doenças cardíacas, vasculares, câncer, síndrome de Down, defeitos de fechamento de tubo neural e baixo peso ao nascer. Considerando o metabolismo anormal de folato, vitamina B12 e homocisteína às mutações do gene de enzimas envolvidas no metabolismo destes podem ser marcadores de fatores de risco materno. O objetivo deste trabalho foi investigar em 240 mães e 240 recém-nascidos (RNs) associações entre os polimorfismos presentes em genes responsáveis no metabolismo da homocisteína e seus substratos caracterizando de forma hematológica, bioquímica e molecular. Foram investigados os polimorfismos C677T e A1298C no gene da MTHFR; A2756G no gene da metionina sintase (MS) e a inserção 844ins68 no gene da enzima cistationina beta sintetase (CBS), utilizando a técnica de PCR – RFLP. Os níveis séricos de homocisteína, vitamina B12 e folatos foram determinados pela técnica de quimioluminescência. As freqüências alélicas dos polimorfismos entre 191 mães e 226 recém-nascidos foram 27,7%. e 25,6%, respectivamente, para o polimorfismo C677T da MTHFR; 14,0% e 14,6%, respectivamente, para o polimorfismo A1298C da MTHFR; 23,9% e 24,5%, respectivamente, para o polimorfismo A2756G da MS; e 22,3% e 20,2%, respectivamente, para a inserção 844ins68 da CBS. Os níveis de Folatos e Vitamina B12 entre mães normais e portadores para os diversos genótipos estudados não demonstraram diferenças estatisticamente significativas. Porém, para os RNs diferenças estatisticamente significantes foram encontradas para os portadores do polimorfismo A2756G e níveis de vitamina B12 (p=0,0023). Diferenças estatísticas significantes foram encontradas entre mães normais e portadores para o polimorfismo A1298C e níveis de homocisteína (p=0,0002). Também foram encontradas diferenças estatisticamente significantes para a ocorrência dos polimorfismos C667T da MTHFR e valores de leucócitos (p=0,0482); A2756G da MS e valores de leucócitos (p=0,0168) e de Ht (p=0,0103); e 844ins68 da CBS e valores de Hb (p=0,0432) no grupo de mães.Para o grupo de RNs os dados hematológicos apresentaram significância estatística apenas entre os valores de plaquetas (p=0,0247) e HCM (p=0,0278) e o polimorfismo A1298C. Os resultados deste estudo contribuem para o entendimento de fatores genéticos relacionados com nutrientes indicando a grande importância de apontar os fatores de risco que possam ser prevenidos e definir estratégias intervencionistas que reduzam os riscos maternos, bem como os cuidados que devem ser tomados durante o acompanhamento pediátrico relacionado aos níveis séricos de Vitamina B12 e folatos e a ocorrência de alterações genéticas de enzimas, uma vez que a presença destas pode conduzir a associação de riscos relacionados a doenças genéticas.
High levels of homocysteine (Hcy) in plasma have been associated with the presence of the polymorphism in the gene MTHFR, Methionine Synthase (MS) and Cystathionine beta Synthase (CBS) or related to nutrition tables, which can alter one of two metabolic pathways involving the precursors of metabolism of Hcy, remethylation or trans-sulphuration. Thus the gene polymorphisms associated with the metabolism of vitamin B12, folate can give high levels of homocysteine, as well as reduction in the levels of folate and vitamin B12 plasma, producing complications during pregnancy as well as changes in methylation of DNA and thus evolve into heart disease, vascular, cancer, Down syndrome, defects in the neural tube closure and low birth weight. Considering the abnormal metabolism of folate, vitamin B12 and homocysteine to mutations of the gene of enzymes involved in the metabolism of these can be markers of risk factors mother. The research aimed to investigate in 240 mothers and 240 newborns (NBs) associations between polymorphisms in these genes responsible for the metabolism of homocysteine and their way of characterizing substrates hematological, biochemical and molecular. We investigated the C677T and A1298C polymorphisms in the gene MTHFR; A2756G in the gene of methionine synthase (MS) and 844ins68 insertion in the gene of the enzyme cystathionine beta synthase (CBS), using the technique of PCR - RFLP. Serum levels of homocysteine, vitamin B12 and folate were determined by the technique of chemiluminescences. Allelic frequencies of polymorphisms between 191 mothers and 226 newborns were 27.7%. and 25.6% respectively, for the MTHFR C677T polymorphism, 14.0% and 14.6% respectively in the A1298C of MTHFR polymorphism, 23.9% and 24.5% respectively in the A2756G polymorphism of MS, and 22.3% and 20.2% respectively in the integration of CBS 844ins68. The levels of Folate and Vitamin B12 between mothers and normal carriers for the various genotypes studied showed no statistically significant differences. But for NBs statistically significant differences were found to carry the A2756G polymorphism and levels of vitamin B12 (p = 0.0023). Significant statistical differences were found between normal and mothers bearers for the polymorphism A1298C and levels of homocysteine (p=0.0002).Were also found statistically significant differences in the occurrence of the MTHFR C667T polymorphism and values of white blood cells (p = 0.0482); A2756G of MS and values of white blood cells (p = 0.0168) and Ht (p = 0.0103) and 844ins68 of CBS and values of Hb (p = 0.0432) in the group of mothers. For the group of NBs data hematological statistically significant only between the values of platelets (p = 0.0247) and HCM (p = 0.0278) and A1298C polymorphism. The results of this study contribute to the understanding of genetic factors related nutrients indicating the great importance of pointing the risk factors that can be prevented and interventionist strategies that reduce risks maternal, and the care that must be taken during the pediatric related to the serum levels of vitamin B12 and folate and the occurrence of genetic modification of enzymes, since the presence of these can lead to association of risks related to genetic diseases.
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Ranguin, Ronald. „Optimisation de la quantification de la chlordécone et mise au point d'un procédé de dégradation par des matériaux hybrides charbons actifs-cobalamine“. Thesis, Antilles, 2015. http://www.theses.fr/2015ANTI0015/document.
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La chlordécone (cld) de formule brute c10cl10o est un pesticide organochloré classé parmi les polluants organiques persistants (pop) par la convention de stockholm en 2009. Ce composé a été appliqué dans les soles bananières des antilles françaisede 1950 à 1993 : ce qui a conduit à une pollution généralisée de l’environnement dans les zones de production de banane. De plus il a été montré une imprégnation généralisée de la biosphère, avec un impact sanitaire décrit dans de nombreuses publications. Il est connu que la cld a une longue persistance dans les sols, conduisant à une contamination des eaux. Aussi, dans les zones polluées de la guadeloupe et de la martinique, les usines de production d'eau ont été équipées de filtres à charbon actif (ca). Cependant, après le traitement, le ca est contaminé, il est alors nécessaire de le régénérer.Un des axes de recherche de l’équipe covachim-m2e « connaissance et valorisation-chimie des matériaux environnement, énergie» est la fabrication de ca préparés à partir des ressources naturelles tropicales telle que la bagasse pour à la fois valoriser des quantités élevées de résidus lignocellulosiques disponibles localement, à un coût modéré, mais surtout pour une adsorption efficace de la cld, afin d’obtenir les informations par le mécanisme d’adsorption de la vb12 sur le ca. Un matériau hybride (mh) composé de ca de la vitamine b12 ou cobalamine (vb12) a été préparé à l’aide d’une fixation non-covalente, par adsorption de manière à préserver l’activité de déchloruration de la vb12.Il est montré que la vb12 réduite par le zinc zérovalent, est capable de dégrader cld, en accord avec les travaux de schrauzer publiés en 1978, montrant que la vb12, réduite par l’acétoine ou bien le borohydrure de sodium était capable dégrader la cld. Les intermédiaires de dégradation produits, ont été caractérisés par chromatographie en phase gazeuse couplée à un spectromètre de masse (cg-sm). Les cinétiques et isothermes d'adsorption de la vb12 sur ca ont été modélisées à l’aide de différents modèles mathématiques ceci permet de comprendre les interactions physico-chimiques mis en jeu entre les deux composants du matériau hybride lors du processus d’adsorption. Il a été révélé que la dynamique d’adsorption est bien décrite par le modèle du pseudo-second ordre. La fixation de la vb12 est plus importante sur le ca bagp1.5, préparé par activation de la bagasse par l’acide phosphorique, avec une valeur capacité d'adsorption maximale déduite du modèle de langmuir de 422 mg.g-1. L’adsorption est favorisée à haute température, et optimale à un ph de 6. En outre, afin d'étudier la stabilité du matériau hybride élaboré, la désorption de la vb12 adsorbée sur la bagp1.5 a également été suivie en milieu aqueux et dans l’éthanol. Le mh ainsi préparé a été caractérisé en utilisant différentes techniques, la méthode de boehm, la microscopie à balayage, la résonance raman, la spectrométrie de fluorescence x, la spectroscopie de photo-électron x, l’infra-rouge à transformée de fourieret aussi par adsorption d’azote.L’objectif de ce travail est d’optimiser la quantification de la cld et de ses intermédiaires de dégradation par une méthode en cg-sm et de mettre au point une méthode de dégradation de la cld en vue de la régénération des ca.Nos travaux ont montré que la vitesse de disparition de la cld est plus élevée pour le matériau hybride, que pour le charbon seul ou la vb12 seule. Les réactions de dégradation de la cld par la vb12 ont montré dans des conditions anaérobies, l’apparition de 3 intermédiaires dérivés de la cld. Ces intermédiaires ont été caractérisés en cg-ms à savoir la mono et dihydrochlordécone, ainsi qu’un dérivé pentachloroindèneChlordecone (cld) with an empirical formula c10cl10o is an organochlorine pesticide classified among the persistent organic pollutants (pops) by the stockholm convention in 2009. This compound was applied to banana plantation in the french west indies from 1950 to 1993: resulting to widespread environmental pollution in banana production areas. In addition it has been shown a generalized pollution of the biosphere, with a health impact described in many publications. It is known that cld has a long persistence in soils, leading to water contamination. Consequently, in the polluted areas of guadeloupe and martinique, the water production plants were equipped with activated carbon filters (ac). However, after water treatment, the ac is contaminated, it is then necessary to regenerate it.One of the research areas of the covachim-m2e team is the elaboration of ac from tropical natural resources such as bagasse to both add value the high amounts of lignocellulosic residues locally available at moderate cost, but as well especially for efficient adsorption of the cld. A hybrid material composed of activated carbon (ac) and vitamin b12 (vb12), known as cobalamin was prepared using a non-covalent attachment, by adsorption to preserve the dechlorination activity of vb12.It is shown that vitamin b12 reduced zerovalent zinc is able to degrade cld, in agreement with the work of schrauzer published in 1978, showing that vitamin b12, reduced by acetoin or sodium borohydride capable of degrading the cld. The intermediate degradation products, were characterized by gas chromatography coupled with mass spectrometric detection (gc-ms) to get right one vb12 adsorption mechanism. To get insight on vb12 adsorption mechanism, kinetic and adsorption isotherms of vb12 on ac were modeled using various mathematical models. It allows to understand the physical and chemical interactions involved between the two components of the hybrid material during the adsorption process. It was revealed that the adsorption dynamics is well described by the model of the pseudo-second order and brouers-sotolongo. Amount of the vb12 fixed on is more important on the bagp1.5 ac prepared by activation of the bagasse by the phosphoric acid, as a maximum adsorption capacity value derived from the langmuir model 422 mg.g-1. Adsorption is favored at high temperature, and at optimum value of ph 6. Furthermore, in order to study the stability of the prepared hybrid material, desorption of the adsorbed from bagp1.5 has also been followed in an aqueous medium and in absolute ethanol. Mh thus prepared was characterized using different technique, the method of boehm, scanning electron microscopy, raman resonance, and x-ray fluorescence spectrometry and x-ray photoelectron, infrared transform fourier spectroscopies and also by nitrogen adsorption.The objective of this work is to optimize the quantification of the cld and its intermeodiates by a gas chromatography method coupled with a mass spectrometer (gc-ms) and to develop a method of degradation of the cld for the regeneration of activated carbon.Our work has shown that the rate of disappearance of cld is higher for the hybrid material than vb12 alone. The degradation reactions of cld by vb12 under anaerobic conditions showed the appearance of 3 cld intermediates: mono and dihydrochlordecone and a pentachloroindène derivative that were characterized by gc-ms
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Besseau, Cyril. „Aspects physiopathologiques et moléculaires des causes gastriques de la malabsorption en vitamine B12“. Thesis, Nancy 1, 2011. http://www.theses.fr/2011NAN10126.
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-- Thèse fournie sans page de titre --Afin de mieux comprendre la physiopathologie des causes gastriques de malabsorption de la vitamine B12, nous nous sommes intéressés au déficit congénital en facteur intrinsèque, une maladie rare caractérisée par une diminution de la sécrétion de facteur intrinsèque (FI) fonctionnel dans le suc gastrique. Dans cette étude, nous rapportons cinq cas porteurs hétérozygotes du variant GIF c.290T>C (p.M97T) et deux cas porteurs hétérozygotes du variant GIF c.435_437delGAA (p.K145_N146delinsN). L'étude fonctionnelle des FI recombinants mutés produits par mutagenèse dirigée a mis en évidence une diminution de l'affinité du FI p.K145_N146delinsN pour la vitamine B12 n'expliquant toutefois pas totalement le phénotype observé chez les sujets. Par ailleurs, une association a été récemment décrite entre le polymorphisme rs601338, c.461 G>A du gène FUT2, codant pour une [alpha]1,2-fucosyltransférase, et les taux plasmatiques de vitamine B12. Afin de compléter notre étude, nous avons évalué l'influence du polymorphisme FUT2 c.461 G>A sur les taux de vitamine B12, de folates et d'homocystéine dans les populations Européennes et Africaines chez 1466 sujets. Notre étude démontre un effet du polymorphisme FUT2 c.461 G>A sur les taux plasmatiques de vitamine B12 et de folates indépendamment de l'âge, du sexe et de l'origine géographique. En conclusion, nos résultats démontrent que le gène du FI (GIF) n'est pas le seul gène impliqué dans la physiopathologie du déficit congénital en facteur intrinsèque. L'étude des malabsorptions d'origine gastrique de la vitamine B12 passe par une approche polygénique dans laquelle le gène FUT2 occupe une place importanteThere are multiple causes of gastric vitamin B12 malabsorption. To get a better understanding of their physiopathology, we are interested in inherited gastric intrinsic factor (GIF) deficiency, a vitamin B12 absorption defect characterized by GIF impaired activity. In this study, we report five cases heterozygous carriers of the variant GIF c.290T>C (p.M97T) and two cases heterozygous carriers of the variant GIF c.435_437delGAA (p.K145_N146delinsN). The study of recombinant mutated GIF produced by site-directed mutagenesis evidenced a reduced affinity for vitamin B12 in the case of GIF p.K145_N146delinsN which does not explain fully the phenotypes observed in our subjects. Recently, an association was described between the FUT2 polymorphism rs601338, c.461 G>A, coding for a fucosyltransferase, and plasma levels of vitamin B12. To complete our study, we assessed the influence of FUT2 c.461 G>A polymorphism on vitamin B12, folate and homocysteine in European and African populations in 1466 subjects. Our study demonstrate a clear effect of FUT2 c.461 G>A polymorphism on both plasma levels of vitamin B12 and folate, regardless of age, gender, and geographic origin. In conclusion, our results demonstrate the GIF gene is not the only gene involved in the physiopathology of inherited GIF deficiency. It is necessary to study the gastric causes of vitamin B12 malabsorption through a polygenic approach, in which the FUT2 gene is an important element
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Nakos, Michail [Verfasser]. „Quantitative determination of vitamin B12 in plants / Michail Nakos“. Hannover : Technische Informationsbibliothek (TIB), 2018. http://d-nb.info/1162903287/34.
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Bunce, Nigel Anthony Colin. „Characterisation of the multivalent Escherichia coli vitamin B12 receptor“. Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.290532.
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Miles, L. „Vitamin B12 status and neurological function in older people“. Thesis, London School of Hygiene and Tropical Medicine (University of London), 2016. http://researchonline.lshtm.ac.uk/2837733/.
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Ageing is associated with a decline in vitamin B12 status. Overt vitamin B12 deficiency can lead to neurologic disturbances but the public health impact for neurological disease of moderately low vitamin B12 status in older people is unclear. This study aimed to assess the relationship between vitamin B12 status and neurologic function in older people by systematically reviewing existing evidence and conducting secondary analyses on an existing high quality dataset. A systematic review of observational studies showed limited evidence of an association of vitamin B12 status with neurological function in older people. The possibility of an association between vitamin B12 status and neurologic function was further explored in cross-sectional analyses of baseline data from the Older People and Enhanced Neurological Function (OPEN) study, which investigated the effectiveness of vitamin B12 supplementation on electrophysiological indices of neurological function in asymptomatic older people with moderately low vitamin B12 status. This secondary analysis did not show any association between any measure of vitamin B12 status with electrophysiological indices or clinical markers of neurologic function. A systematic review of intervention studies suggested no benefits of vitamin B12 supplementation on neurologic function in asymptomatic older people; but it remained possible that improvement is only apparent in people with the lowest vitamin B12 status. This hypothesis was explored in further secondary analyses of OPEN data: there were no differences in the neurologic response to vitamin B12 supplementation according to baseline or change in vitamin B12 status. The available evidence indicates that concerns over the neurologic impact of moderately low vitamin B12 status in otherwise healthy older people may be unwarranted. Evidence is insufficient to support population screening for moderate vitamin B12 deficiency or population-wide recommendations for vitamin B12 supplementation in healthy asymptomatic older people, even among those with the lowest vitamin B12 status.
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Vedantam, Venkata Sri Harsha, Neethu Nair, CHRISTINE MOORE und Diana Gorman-Nunley. „VITAMIN B12 DEFICIENCY ANEMIA-ASSOCIATED MALIGNANCY ACCELERATED BY SUPPLEMENTATION“. Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/49.
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Vitamin B12 and folate are necessary for bone marrow progenitor growth and division. Deficiencies are common in lymphoproliferative disorders due to increased demands of rapidly growing malignant cells. Isolated vitamin B12 deficiency is seen in 13% of these patients and may be their only manifestation. We present the case of vitamin B12 deficiency anemia due to an underlying malignancy that was discovered following supplementation.
A 77-year-old nonsmoker female with chronic kidney disease and hypothyroidism presented to her internist with dyspnea, tachycardia and unintentional 7-pound weight loss. Age-appropriate cancer screenings were up-to-date. Physical exam was notable for an overweight female with tachycardia and trace ankle edema bilaterally. Electrocardiogram demonstrated sinus tachycardia. Labs were remarkable for hemoglobin 10.3 mg/dL (12.1 mg/dL one year ago) and serum B12/mL. She was started on intramuscular vitamin B12 supplementation. At her one-month follow-up, she reported debilitating gastrointestinal distress, rash, and fatigue lasting 5-6 days with every vitamin B12 injection. Physical exam was notable for 20-pound weight loss. Labs revealed hemoglobin 9.9 mg/dL despite serum B12 750 pg/mL and worsening kidney function with marked proteinuria. Additional work-up by primary team and subsequent Hematology & Oncology referral demonstrated elevated M-spike on urine protein electrophoresis and abnormal bone marrow biopsy suspicious for lymphoid malignancy. CT abdomen and whole body PET scan revealed increased uptake in the T12 vertebrae and multiple nodal basins consistent with stage IV lymphoma. Biopsy of vertebral body confirmed diffuse large B-cell lymphoma. The patient received one cycle of chemotherapy with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone). Her course was complicated by pathologic hip fracture requiring hospitalization and surgical repair. The patient died following cardiac arrest in the setting of septic shock from sigmoid colon perforation 7 months from initial presentation.
Vitamin B12 and folate play critical roles in nucleic acid synthesis for bone marrow progenitors. Vitamin B12 deficiency arrests cell growth and division, leading to macrocytic anemia and various neuropsychiatric manifestations. It is a common diagnosis with numerous causes: autoantibodies to digestive proteins, poor dietary intake, small bowel malabsorption, etc. Diagnose with low hemoglobin (/dL or 13 mg/dL in non-pregnant women or men, respectively) and mean corpuscular volume >100 fL plus low serum B12 or elevated homocysteine and methyl-malonic acid levels. Replacement is given orally or intramuscularly. Vitamin B12 and folate deficiencies are found in lymphoproliferative disorders due to increased demands of rapidly growing malignant cells. Isolated vitamin B12 deficiency is seen in 13% of patients and may be the only clue. Replacement will not resolve their anemia. Physicians should monitor patients receiving supplementation. If anemia fails to improve or patients experience systemic symptoms, further investigation for lymphoid malignancies is warranted. This patient had dramatic deterioration with acceleration of underlying malignancy following vitamin B12 replacement. We believe supplementation enabled malignant lymphoid precursors to resume cell cycle growth and division. Only one report of vitamin B12 supplementation associated with unmasking a lymphoid malignancy exists in literature. Further research is needed to support whether supplementation can accelerate lymphoid malignancies.
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Sillaots, Susan L. (Susan Linda). „Heterogeneity in cblG : differential binding of vitamin B12 to methionine synthase“. Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60091.
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Fibroblasts from patients with functional methionine synthase deficiency can be divided into 2 complementation classes, cblE and cblG. Both have low levels of intracellular methylcobalamin. Both groups also demonstrate low levels of incorporation of label from 5-methyltetrahydrofolate into macromolecules. Under standard reducing conditions, methionine synthase specific activity is normal in cblE fibroblast extracts, but is low in cblG fibroblast extracts. Seven cblE and seven out of ten cblG cell lines demonstrate levels of accumulation of ($ sp{57}$Co) CN-Cbl in fibroblasts comparable to that of control cells. They exhibit similar proportions of label associated with the two intracellular cobalamin binders, methylmalonyl-CoA mutase and methionine synthase. The remaining three cblG cell lines exhibit a lower level of cobalamin accumulation, and demonstrate a lack of cobalamin association with the enzyme methionine synthase. The specific activity of methionine synthase is almost undetectable in the three cblG cell lines that showed no such association. These results demonstrate heterogeneity within the cblG group and suggest that the defect in cblG affects the methionine synthase apoenzyme.
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Vassiliadis, Anthony. „Electron microscopic radioautographic localization of [57Co]Cobalamin in cb1F and control cells“. Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55659.
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Willekens, Jérèmy. „Carence précoce en donneurs de méthyles dans le cervelet : mécanismes moléculaires et épigénétiques“. Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0303/document.
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Les carences précoces en donneurs de méthyles (vitamines B9 et B12 notamment) sont à l’origine de malformations congénitales. Elles exercent un effet délétère sur le développement du cerveau et sont associées à une augmentation de l’incidence de pathologies neurologiques et neurodégénératives à l’âge adulte. Un modèle murin de carence en donneurs de méthyles, le modèle MDD, a été développé au laboratoire et a permis d’étudier la réponse à cette carence, et de mettre en évidence des altérations de la structure cérébrale et des défauts de locomotion chez les ratons issus de mères carencées. Ce comportement est contrôlé par le cervelet, dont on sait que le développement est altéré chez les MDD. En revanche, les mécanismes moléculaires mis en jeu dans la réponse à la carence dans le cervelet restent peu compris. Afin d’étudier les gènes et voies de signalisation dérégulés chez les MDD, nous avons réalisé l’étude du transcriptome du cervelet des ratons carencés. Puis, nous nous sommes intéressés aux modifications épigénomiques engendrées par la carence en analysant leur miRnome et les modifications des protéines histones dans leur cervelet. Nous avons mis en évidence des altérations des voies wnt, dans le cervelet des femelles carencées, qui n’ont pas été retrouvées chez les mâles. De même, de nombreux gènes impliqués dans le développement et les fonctions synaptiques sont dérégulés chez les femelles. Nous avons aussi montré des variations de plusieurs marques d’acétylation et de méthylation des histones chez les MDD. Enfin, de manière plus ciblée, nous avons mis en évidence un miARN dont l’expression diminue dans le cervelet des ratons carencés : miR-344-5p. Nos premiers résultats semblent indiquer qu’il est impliqué dans le contrôle de la mort cellulaire. Ces résultats montrent l’implication de dérégulations globales dépendantes du sexe mais aussi des altérations ciblées dans la réponse à la carence. Une amélioration de la compréhension de ces mécanismes moléculaires nous permettra de mieux appréhender le lien qui existe entre carence précoce en donneurs de méthyles, développement cérébral et incidence de pathologies à l’âge adulteEarly methyl-donor deficiencies (e.g. B9 and B12 vitamins) can lead to congenital disabilities. They are behind developmental abnormalities of the brain, and are associated with the development of neurological and neurodegenerative diseases at adulthood as well. In the lab, we developed a methyl donor deficiency rat model called MDD. It has allowed us to show structure alterations of several brain areas and also locomotor coordination impairments in pups born from dams fed a MDD diet. Cerebellum is the brain structure involved in the control of this behavior and we know its development is delayed in MDD. However, the molecular mechanisms underlying methyl donor deficiency still remain misunderstood in this brain structure. In order to study genes and signaling pathways dysregulated in MDD, we performed transcriptomic analysis of deficient pups’ cerebellum. We also led miRnome analyses and histone modifications investigations with the purpose of understanding epigenomic modifications caused by MDD. We showed alterations of wnt signaling pathways in female’s cerebellum which we did not find in males. We also found that several genes involved in cerebellum’s development and synaptic function were dysregulated in females. Regarding epigenomic regulation, acetylation and methylation of histone marks were also modified in females. Finally, we chose miR-344-5p as an interesting candidate to study more specific epigenetic modifications. Its expression is decreased in MDD and it seems to be involved in cellular death control, according to our first results. These results shed light on global dysregulations, in a sex-dependent manner, as a consequence of methyl donor deficiency but also more specific alterations. A better understanding of the molecular mechanisms taking place in response to MDD could help us to link methyl donor deficiency, brain development and neurodegenerative pathologies occurrence at adulthood
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Safi, Amal. „Contribution à la purification et à la caractérisation physico-chimique des protéines de transport enterocytaire de la vitamine b12“. Nancy 1, 1994. http://www.theses.fr/1994NAN10438.
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Ravnum, Solveig. „Translational regulation of genes in salmonella typhimurium by vitamin B12“. Doctoral thesis, Uppsala University, Department of Cell and Molecular Biology, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-547.
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In this thesis I have studied the mechanism by which vitamin B12 regulates the expression of the cob operon and the btuB gene in Salmonella typhimurium. The cob operon encodes most of the 25 genes required for the de novo synthesis of vitamin B12, and the butB gene encodes the outer membrane protein needed for transport of exogenous vitamin B12 into the cell. Vitamin B12 is used as a cofactor in four enzymatic reactions in Salmonella typhimurium. The regulation by vitamin B12 of the cob operon and the btuB gene requires sequences in the long leader regions of the respective mRNAs. Proper folding of the reader mRNA is essential for normal repression, in particular a hairpin structure that sequesters the ribosomal binding site (RBS). The upstream leader region contains two conserved sequence elements that are required for the vitamin B12 regulation; the translational enhancer (TE) element element and the B12 box. The TE element confers its enhancer function by resolving the downstream inhibitory RBS hairpin through basepairing with nucleotides in the stem. In the presence of vitamin B12, either B12 itself, or a B12 regulatory factor binds to the upstream reader region and prevents the enhancer function. This will inhibit unfolding of the RBS hairpin and repress translation.
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Byck, Susan. „Cross-correctional studies in inborn errors of vitamin B12 metabolism“. Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59259.
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Human skin fibroblasts derived from patients with all 7 known inborn errors of vitamin B$ sb{12}$ metabolism have been studied for functional integrity of methylmalonyl CoA mutase and methionine synthase. Cocultivation of cblC and cblF fibroblasts in the absence of polyethylene glycol resulted in a twofold increase over the expected in both ($ sp{14}$C) propionate and ($ sp{14}$C) methyltetrahydrofolate incorporation into acid-precipitable material, suggesting that metabolic cooperation between cells occurs. CblD fibroblasts, which are biochemically similar to cblC cells (Goodman et al, 1970; Willard et al, 1977), do not cooperate metabolically when mixed with cblF cells. Partial correction in phenotype was seen in mixtures of cblD and cblG cells, but not cblC and cblG cells. These observations lend further support for the division of cblC and cblD disease into two discrete complementation classes. Cocultivation of cblF fibroblasts with both cblE and cblG cells also resulted in partial correction in phenotype.($ sp{14}$C) Propionate incorporation in both cblC and cblF cells exposed to conditioned medium from control cells was increased more than twofold. ($ sp{14}$C) methyltetrahydrofolate incorporation in cblC cells exposed to conditioned medium from cblF cells was increased twofold. This suggests the presence of a diffusible factor correcting the defect in the mutant cell lines.
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Clegg, R. „Radiation-chemical studies of some sulphophthalocyanine complexes and vitamin B12“. Thesis, University of Salford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374501.
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Al-Naieb, M. A. B. „Szilard-Chalmers effects in sulphonated metallophthalocyanines, metalloporphyrins and vitamin B12“. Thesis, University of Salford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376856.
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Bawazeer, Nahla M. „Vitamin B12 and folate status during pregnancy among Saudi population“. Thesis, University of Warwick, 2011. http://wrap.warwick.ac.uk/49940/.
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T2DM is a growing health problem worldwide. It is now increasingly being diagnosed earlier in life. The factors involved in such an epidemic are complex. The intrauterine environment has long been known as an important contributor to many diseases including metabolic disorders such as T2DM. Recently, there is emerging evidence for maternal micronutrients affecting vital developmental processes in utero which can adversely “programme” the offspring to develop metabolic disorders in later life. Thus, “gene-diet” interaction during foetal development is likely to be a significant contributor to the epidemic of T2DM. In particular, the intrauterine imbalance between the two related vitamins, vitamin B12 and folate, affect DNA methylation and in turn programme the foetus for the whole life. Evidence from mandatory folic acid fortification studies suggests that in the presence of adequate folate, neural tube defects due to vitamin B12 insufficiency have tripled. In India, children born to mothers with “high folate and low vitamin B12” had higher adiposity and insulin resistance. Therefore, micronutrient status during pregnancy is likely to have a significant impact on the metabolic risk of the offspring. This thesis examines whether vitamin B12 insufficiency is prevalent in pregnancy, especially in a non-vegetarian population across the world as well as the Saudi pregnant population. As estimated intake is an accepted measure for micronutrient levels, we also examined the relationship between estimated vitamin B12 and folate intake with actual levels in the blood. We have found that vitamin B12 insufficiency was not uncommon during pregnancy across the world even in the non-vegetarian population and is also common in the Saudi population. Surprisingly, vitamin B12 insufficiency was observed in 50% of the tested population even in the presence of adequate vitamin B12 intake. In addition, we have also shown for the first time in the Saudi population that maternal BMI is inversely related to vitamin B12 levels, particularly in pregnancy. Even though we have shown a similar (or worse) picture in mothers with gestational diabetes, this study needs to be replicated, as our numbers are too small. Prospective studies linking the role of vitamin B12 insufficiency especially in the presence of high folate on birth outcomes in the Saudi population as well as intervention studies investigating the role of vitamin B12 supplementation in women of childbearing age and in pregnancy are urgently needed.
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Abel, Stefan. „The physiological effect of vitamin B12 deficiency in human blood“. Thesis, Stellenbosch : Stellenbosch University, 1990. http://hdl.handle.net/10019.1/69031.
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Thesis (MSc) -- Stellenbosch University, 1990.ENGLISH ABSTRACT: The main aim of this workpiece was to establish the physiological parameters against which a vitamin Bu deficiency could be measured. A comparison between the hematological values of healthy patients and those suffering from pernicious anemia due to vitamin Bu deficiency was done. A specific case of pernicious anemia was used in the comparison of abnormal values to the values of normal healthy patients. The comparison consisted of blood analyses with the help of specified instruments, photomicrographs of bone marrow and blood smears and statistical data. A Coulter Counter Model ZF was used for the hematological analyses of blood, a radio-isotope assay for serum vitamin B u was done and photomicrographs were taken with a NIKON Microflex camera with photomicrographic attachments. The importance of vitamin Bu has been shown in this workpiece. With the use of techniques and certain instruments, the effects of a shortage of vitamin Bu has been shown. Analyses of the blood from normal ,healthy patients was compared to that of patients suffering from pernicious anemia. It was demonstrated that pernicious anemia is characterized by a low erythrocyte count, hematocrit (Het), hemoglobin (Hb) and vitamin Bu levels together with a higher mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV). In severe cases of pernicious anemia these levels are extremely high or low as the case may be. Together with these values, the investigation of pernicious anemic blood and bone marrow smears revealed abnormally large erythrocyte precursors and fewer leucocytes than normal. Abnormally shaped cells, called macrocytes, were seen which was due to the disruption in deoxyribonucleic acid (DNA) synthesis caused by the vitamin Bu deficiency. This study produced a set of hematological reference values. The comparative study between healthy and pernicious anemic patients demonstrated a significant drop in serum vitamin B12 values during pernicious anemia. The hematological effect was illustrated by the Coulter Counter blood analysis results and the microscopic examination revealed the presence of megaloblastic erythrocytes, oval erythrocytes, pear-shaped poikilocytes and polymorphonuclear neutropbils with hypersegmented nuclei in blood smears I during vitamin B12 deficiency. This dianoses can be supported by the presence of megaloblasts and metamyelocytes in pernicious anemic bone marrow.
AFRIKAANSE OPSOMMING: Die hoof doel van hierdie werkstuk was om fisiologiese grense te bepaal waarteen 'n vitamien B12 tekort gemeet kan word. 'n Vergelyking tussen die hematologiese waardes van gesonde persone en die van pasiente met pernisieuse anemie wat ontstaan het as gevolg van 'n vitamien B12 tekort was uitgevoer. Die waardes verkry vanaf 'n spesifieke geval van pernisieuse anemie. was vergelyk met waardes vanaf normale gesonde persone. Hierdie vergelyking het bestaan uit bloed analises, fotomikrograwe van bloed en beenmurg smere en statistiese data. Die hematologiese bloed analises was met behulp van 'n Coulter Teller model ZF uitgevoer. 'n Radio-isotoop bepaling vir serum vitamien B12 was gedoen en fotomikrograwe was met 'n NIKON Microflex kamera geneem. Die belang van 'n vitamien B12 tekort was in hierdie werkstuk gedemonstreer. Die effek van hierdie tekort is deur die gebruik van sekere instrumente en tegnieke aangedui en die resultate hiervan is vergelyk tussen gesonde persone en pasiente met 'n vitamien B12 tekort. Hierdie studie het bevestig dat pernisieuse anemie gekenmerk word deur verlaagde eritrosiet, hematokrit (Het), hemoglobien (Hb) en vitamien B12 vlakke tesame met verhoogde gemene korpuskulere hemoglobien (GKH) en gemene korpuskulere volume (GKV) vlakke. Gedurende ernstige gevalle van pernisieuse anemie kan hierdie waardes uitermatig hoog of laag wees. Benewens hierdie waardes het die ondersoek van bloed en beenmurg gedurende vitamien B12 tekort, abnormale groot eritrosiet voorgangers en 'n verminderde hoeveelheid leukosiete getoon. Abnormale sel vorms was ook sigbaar a.g.v. die onderbreking in DNA sintese wat deur 'n vitamien B12 tekort veroorsaak word. Pernisieuse anemie word verkry wanneer daar 'n vitamien B12 en/of folaat tekort in die dieet is of wanneer hierdie vitamiene nie geabsorbeer kan word nie. Die teenwoordigheid van makrosiete, ovaal eritrosiete, peervormige poikilosiete en polimorfonuklere neutrofiele met hipergesegmenteerde keme in bloedsmere dui op 'n megaloblastiese anemie. Hierdie diagnose kan ondersteun word deur die aanwesigheid van megaloblaste en reuse metamielosiete in die beenmurg. Die bepaling van vitamien B12 en folaat vlakke in die bloed kan as addisionele bewysstukke vir 'n volledige diagnose dien. Gedurende hierdie studie is daar 'n stel hematologiese verwysingswaardes vasgestel. Die vergelykende studie tussen gesonde persone en pasiente met pernisieuse anemie het getoon dat daar 'n beduidende verlaging in serum vitamien B12 waardes gedurende pernisieuse anemie is. Die hematologiese effek was ook duidelik waameembaar in die Coulter teller se bloed analiese en mikroskopiese ondersoeke het die · teenwoordigheid van makrosiete, ovaal eritrosiete, peervormige poikilosiete en polimorfenuklere neutrofiele met hipersegmenteerde keme in bloedsmere aangedui. Hierdie diagnose kan ondersteun word deur die aanwesigheid van megaloblaste en reuse metamielosiete in die beenmurg.
This study was financially aided by a bursary from the CSIR.
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Pankiv, I. V. „Vitamin B12 levels in metformin-treated type 2 diabetes patients“. Thesis, БДМУ, 2020. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/18338.
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Aeschimann, Simon. „Hypersegmentierte Neutrophilenkenren im peripheren Blutbild ohne Vitamin-B12- und Folsäuremangel /“. Bern, 1990. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Sampaio, Romildo Martins. „Estudo da produção de vitamina B12 por bacterias dos generos propionibacterium e pseudomonas“. [s.n.], 1999. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255441.
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Orientador: Ranulfo Monte AlegreTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-07-28T14:47:55Z (GMT). No. of bitstreams: 1 Sampaio_RomildoMartins_D.pdf: 3919745 bytes, checksum: 716e0ca6a5f49638e524df0464557d83 (MD5) Previous issue date: 1999
Resumo: O presente trabalho trata do estudo da produção de vitamina B12, consistindo das seguintes etapas: seleção do melhor microrganismo produtor; seleção da melhor fonte de substrato, e do meia de cultura, avaliação, modelagem e otimização, das variáveis experimentais e fermentação em reator de bancada, para a obtenção das condições de operação e parâmetros cinéticos que influenciam no rendimento de produção da vitamina. A primeira fase consistiu da seleção do melhor microrganismo produtor a ser utilizado, nos estudos posteriores. Partiu-se das seguintes culturas tidas como boas produtoras de B12: Propionibacterium jensenii DSM 20274, Propionibacterium freudenreichii ATCC 9614, Propionibacterium shermanii ATCC 62Q1, Pseudomonas sp. ATCC 13867 e mais três mutantes isolados. Aqui como nas duas próximas etapas, os ensaios, foram realizados em frascos agitados, com base nos resultados, obtidos, decidiu-se pela seleção do mutante Pseudomonas P3, que chegou a uma produção máxima de 3,86 mg B12/1. A escolha da melhor fonte de substrato e do meio de cultura com composição mais indicada ocorreu paralelamente à escolha do microrganismo. Foram testadas lactose e sacarose e mais três composições de meio: meio 1, meio 2, e meio 3. A sacarose e o meio 1, associados ao mutante selecionado, proporcionaram os melhores rendimentos de B12, produção de biomassa e consumo de substrato. As culturas de. Propionibacterium mostraram maior um maior consumo de lactose do que as Pseudomonas. Na terceira etapa, estudou-se a influência de sete variáveis experimentais, previamente pesquisadas e selecionadas, na produção de B12. Foram elas: idade do inoculo, tempo de fermentação, temperatura, pH, concentração de substrato, de 5,6 DMI e de cobalto. Até a etapa de otimização, foram efetuados um planejamento fracionário, dois planejamentos com composto central e um caminho de ascendência máxima. As variáveis com seus respectivos níveis otimizados, que mais influenciaram a resposta, foram: concentração de 5,6 DMI (98,8 mg/l), temperatura (34,6 °C) e pH (7,14). O planejamento experimental permitiu um aumento de quase. 100% na produção de vitamina, alcançando um máximo de 7,57 mg BI2/1. Os ensaios no fermentador de bancada objetivaram verificar a influência do tempo de adição de 5,6 DMI, KLa e controle de pH no rendimento da vitamina. Concluiu-se que o tempo, ótima de adição, do precursor e a nível de Kls mais, indicado, foram respectivamente, 48 h e 36,8 h-1. Por outro lado, percebeu-se que o controle do pH não melhorou, a produção de vitamina nem aumentou, a velocidade de crescimento do microrganismo
Abstract: The present deals with the study of the production of vitamin B12, consisting of the following stages: selection of the best producing microorganism, selection of the best substrate, source, and the more, suitable medium of culture; evaluation, modeling and optimization of the experimental variables and; fermentation in a bench-fermentor for the obtaining of the operation, conditions and. kinetic parameters that, influence, the yield of the vitamin. The first phase consisted of the selection of the best producer microorganism to be used during the work. The following strains were used: Propionibacterium freudenreichii AICC 9614, Propiombacleruan jensenii. DSM 20274, Propianibacterium shermanii ATCC 6207, Pseudomonas sp. ATCC 13867 and more three mutants isolated. Here as in o stages, the experiments were, conducted in shake-flasks Based on the obtained results, the mutant Pseudomonas P3 was selected, producing a maximum of 3.86 mg BJ2/L. The selection of the best, substrate source, and medium composition was done parallelly to the microorganism selection. Were tested sucrose, lactose and three compositions of medium: medium 1 medium 2 and medium 3. The sucrose and medium 1, associated to the mutant P. P3, provided the best yields of B12, biomass production and substrate consumption. The strains of Propionibacterium showed larger ability in the lactose degradation than Pseudomonas and its mutants. In the third stage it was studied the influence of seven experimental variables in the production of vitamin B12: age of inoculum, time of fermentation, temperature, pH, substrate concentration, 5,6 Dimethylbenzimidazole (DMT> concentration and cobalt concentration. Up to the optimization step were realized a fractional factorial design, a steepest ascent path and two central composite design The most significant parameters, with respective optimized levels, were: 5,6 DMI (98.8 mg/L), temperature (34.6 °C) and pH (7-14)-. The experimental design allowed an. increase of almost 100% in. the Vitamin production, reaching a maximum of 7.57 mg B12/L. The experiments in the bench-fermentor were done to verify, the influence of the time of addition of 5,6 DMI, Kla and pH control in the yield of vitamin B12. The better time of addition and level of KLa, were respectively 48 hr and 36.8 hr-1. The control of pH did not improve the vitamin production
Doutorado
Doutor em Engenharia de Alimentos
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Suarez, Moreira Edward. „Vascular biochemistry of vitmain B12 exploring the relationship between intracellular cobalamin and redox status in human aortic endothelial cells /“. [Kent, Ohio] : Kent State University, 2010. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1270788182.
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Thesis (Ph.D.)--Kent State University, 2010.Title from OhioLINK ETD abstract webpage (viewed Apr. 28, 2010). Advisor: Nicola E. Brasch. Keywords: Vitamin B12; Cobalamin Metabolism; Oxidative Stress; Reactive Oxygen Species; Cobalamin Synthesis.
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Jackson, Rebecca J. „Hydrocobaltation/dehydrocobaltation reactions in organic synthesis“. Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282637.
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