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1

Divya, Jagasia, and 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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Zant, Ayman [Verfasser], and 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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3

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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4

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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5

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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6

Heilmann, Romy Monika, Niels Grützner, Christina M. Iazbik, Rosana Lopes, Seth C. Bridges, Jan S. Suchodolski, Guilermo C. Couto, and 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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7

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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8

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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9

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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10

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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11

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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12

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 BAbstract not available
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13

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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14

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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15

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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16

Vedantam, Venkata Sri Harsha, Neethu Nair, CHRISTINE MOORE, and 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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18

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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19

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 Lopes
Resumo: 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)
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20

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-Bizzacchi
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
Made available in DSpace on 2018-08-24T12:13:12Z (GMT). No. of bitstreams: 1 Barnabe_Aline_D.pdf: 1712567 bytes, checksum: 647e2ea59dbddb21e153a8e6ceae61cc (MD5) Previous issue date: 2014
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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21

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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22

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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23

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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24

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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25

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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26

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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27

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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28

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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29

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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30

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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31

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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32

Johansson, Anna. "Alheimers sjukdom och förändrade nivåer av folat, vitamin B12 och homocystein." Thesis, Linnéuniversitetet, Institutionen för kemi och biomedicin (KOB), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-52070.

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Bakgrund: Alzheimers sjukdom (AD) utgör vanligaste formen av demenssjukdomar i Sverige. Alzheimers sjukdom klassas som en neurodegenerativ sjukdom och karaktäriseras av proteininlagringar samt av hjärnatrofi. Ungefär 150 000 personer i Sverige lever idag med demenssjukdomar, varav 90 000 lider av AD och varje år insjuknar ytterligare 20 000 i demens. Vitamin B12 och folat anses utgöra en viktig del med avseende på hjärnans kognitiva funktioner. Låga nivåer av vitamin B12 och/eller folatbrist medför en höjning av Homocystein (Hcy) i blodet. Syfte: Syftet med examensarbetet var att undersöka det eventuella sambandet mellan nivåerna av vitamin B12, folat respektive Hcy och risken för att drabbas av Alzheimers sjukdom. Utifrån syftet ställdes 2 frågeställningar upp. Frågeställning 1: Finns det en risk att utveckla AD vid förändrade nivåer av folat, vitamin B12 och Hcy. Frågeställning 2: Finns det ett samband mellan förändrade nivåer av folat, vitamin B12 och Hcy vid diagnosticerad AD. Metod: Detta arbete är en litteraturstudie baserat på 7 vetenskapliga artiklar. Resultat: Samtliga fem studier utifrån frågeställning 2 visade att AD-patienter hade höga nivåer av Hcy än kontrollpatienterna. Två av dessa studier visade även att AD-patienterna hade lägre nivåer av både vitamin B12 och folat än kontrollindividerna. Två ytterligare studier av de fem samtliga visade också lägre nivåer av folat än kontrollgruppen.  Totalt 4 av 5 studier visade lägre nivåer av folat. Utifrån frågeställning 1 visade studie 1 att det var enbart de låga nivåerna av folat från baslinjen som förespråkade till insjuknande i AD. Studie 2 indikerade att individer med låga nivåer av vitamin B12 och folat har 2 gånger högre risk för att insjukna i AD. Slutsats: Det är fortfarande oklart idag huruvida nivåerna av vitamin B12, folat och Hcy påverkar riskerna för att utveckla AD. Studierna visar att det finns ett samband mellan markörerna kopplat till AD. Det krävs mer forskning för att fastställa det eventuella sambandet mellan vitamin B12, folat och Hcy. Fler patienter måste undersökas och flera studier bör utföras för att kunna fastställa associationerna av dessa ämnen med AD. Studierna visar att det finns ett samband mellan markörerna kopplat till AD. Fler studier som tar hänsyn till inklusionskriterierna med avseende på nutritionsstatus bör göras.  Detta eftersom lågt BMI (Body Mass Index) kan vara av betydelse för uppkomsten samt riskerna för att insjukna i AD.
Background: Alzheimer's disease (AD) is the most common form of dementia in Sweden. Alzheimer's disease is classified as a neurodegenerative disease and is characterized by protein deposits in certain parts of the brain accompanied with brain atrophy. 150 000 people in Sweden today suffer from dementia, of whom 90 000 suffer from AD and every year another 20 000 dementia cases reside. The highest risk factor of developing AD is old age. After the age of 65, the risk is considerably higher for developing AD. Vitamin B12 and folate is considered to be an important part with respect to the brain's cognitive functions. Folate acts as a donor of the methyl groups in a reaction catalysed by methionine synthase, which produce methyl cobalamin which needs to be metabolised to methionine from Homocystein (Hcy). Low levels of vitamin B12 and/or folate deficiency leads to an increase of Hcy in the blood. Objective: The aim of this study was to investigate the possible link between low levels of vitamin B12, folate and Hcy and the risk of developing Alzheimer's disease. Two question based on the objective of the study were set. Question 1: Is there any risk of developing AD with altered levels of folate, vitamin B12 and Hcy? Question 2: Is there a relationship between altered levels of folate, vitamin B12 and Hcy in diagnosed AD? Methods: This work is a literature study based on 7 scientific articles. Results: All five studies from question 2 showed that AD patients had high levels of Hcy compared to control patients. Two of these studies also revealed that AD patients had lower levels of both vitamin B12 and folate than control individuals. Furthermore 2 out of the 5 studies also displayed lower levels of folate compared to the control group, resulting in a total of 4 out of 5 studies showing lower levels of folate. Based on question 1, study 1 presented that only low levels of folate at baseline correlated with developing AD. Study 2 indicated that individuals with low levels of vitamin B12 and folate had twice times higher risk of developing AD. Conclusion: It is still unclear whether the levels of vitamin B12, folate and Hcy affect AD. The studies investigated show that there is a correlation between the investigated markers linked to AD. However, more research is needed to be able to determine the possible link between vitamin B12, folate and Hcy. More patients must be investigated and several studies should be performed to determine the associations of these subjects with AD.  More studies that take in consideration of nutritional status must be carried out, due to the fact that low BMI (Body Mass Index) may be of importance for the risk of developing AD.
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33

Moore, Simon John. "Elucidation of the anaerobic biosynthesis of vitamin B12 in Bacillus megaterium." Thesis, University of Kent, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.594101.

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Vitamin B12 (cobalamin) is one of Nature's most complex small molecules. It is a cobalt-containing modified tetrapyrrole that plays a number of key metabolic roles in many prokaryotic systems and is also essential to the biochemistry of higher animals. However, it is made by only certain bacteria, requiring around thirty enzymatic steps for its complete de novo construction. Surprisingly, the nutrient is synthesised by one of two related, though genetically distinct, pathways that represent aerobic or anaerobic routes. The anaerobic pathway has remained poorly characterised due to the instability of the pathway intermediates to oxygen and the low activity of enzymes, and is the focus of the research reported in this thesis. The Gram-positive aerobe Bacillus megaterium has previously been used for the commercial production of cobalamin and has a complete anaerobic pathway. Several genes, (termed chi for 9,obinamide biosynthesis) from the cobalamin biosynthetic pathway have been cloned and overexpressed individually within the host B. megaterium DSM319. One of the major bottlenecks in the anaerobic pathway is the ring contraction step, where only limited yields « 5 %) of product had previously been obtained using crude-lysate based incubations. By studying the purified B. megaterium CbiH60 enzyme, an efficient method was developed to allow the generation of the ring-contracted product cobalt-factor IV in high yields. This breakthrough then permitted the characterisation of many of the down-stream steps in the pathway to be characterised by using other purified cobalamin biosynthetic enzymes from B. megaterium, by incubating combinations of purified enzymes with cobalt-factor IV and the appropriate cofactors (SAM, NADH). This has resulted in the successful step-by-step elucidation of the anaerobic cobalamin pathway, including the isolation of the long sought-after and elusive intermediates cobaltprecorrin- 5, -6A, -6B, -7 and -8. An enzyme-cocktail approach has also resulted in a full in vitro synthesis of cobyrinic acid (the first known stable intermediate in the pathway) from 5-aminolevulinic acid has been demonstrated, involving a full 15 enzymatic steps. The exposition of the anaerobic pathway has been interpreted with respect to the chemical logic of the metabolic process and the evolution of multifaceted biochemical pathways.
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34

Deme, Justin. "Protein-protein interactions for early intracellular vitamin B12 metabolism in mammals." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123014.

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Vitamin B12, or cobalamin, is a water soluble vitamin required as cofactor for two mammalian enzymatic processes: homocysteine remethylation to methionine in the cytoplasm using methionine synthase (MS), and fatty acid/amino acid metabolism in the mitochondrion using methylmalonyl-CoA mutase (MCM). Whereas the molecular nature of intracellular cobalamin metabolism in mammals remains poorly understood, the proteins MMACHC, MMADHC, LMBD1 and ABCD4 are implicated in its early uptake and processing. Due to the inherent challenges associated with the cellular utilization of cobalamin, we propose that these proteins mediate its early intracellular channeling; the objective of this thesis was to characterize the protein-protein interactions that coordinate this process.To gain insight into the function of MMADHC, recombinant isoforms were purified and low-resolution structural features were determined. MMADHC is monomeric and, in solution, adopts an extended conformation, with regions of disorder identified at the N-terminal domain. Panning combinatorial phage libraries against recombinant MMADHC allowed the mapping of putative sites of interaction on MMACHC. Kinetic analyses using surface plasmon resonance (SPR) confirmed a sub-micromolar affinity for the MMACHC–MMADHC interaction. Based on these studies, we propose that the function of MMADHC is exerted through its structured C-terminal domain via interactions with MMACHC in the cytoplasm.Clinical phenotypes and subcellular location of MS and MCM dictate that MMACHC functions in the cytoplasm while MMADHC functions at a branch point in the pathway in both the cytoplasm and the mitochondrion. To demonstrate that the MMACHC–MMADHC interaction is physiologically plausible, we used immunofluorescence and subcellular fractionation to confirm that MMACHC is cytoplasmic while MMADHC is dual-localized to the cytoplasm and mitochondria. Protein interaction analyses were extended by describing the recombinant production of the lysosomal membrane proteins LMBD1 and ABCD4. Detergent-solubilized LMBD1 and ABCD4 each formed homodimers in solution. SPR provided direct in vitro binding data for an LMBD1–ABCD4 interaction with low nanomolar affinity. Consistent with our phage display predictions, MMACHC interacted with LMBD1 and ABCD4 with high affinity.Our results support a model whereby membrane-bound LMBD1 and ABCD4 regulate the vectorial delivery of lysosomal cobalamin to cytoplasmic MMACHC, preventing cofactor dilution to the cytoplasmic milieu and protecting against inactivating side reactions. Subsequent formation of a cytoplasmic MMACHC–MMADHC complex then processes and partitions this cofactor to the downstream enzymes MCM and MS. These studies identify and characterize multiprotein complexes, advancing our basic understanding of early intracellular cobalamin metabolism.
La vitamine B12, ou bien la cobalamine, est une vitamine soluble requise pour deux processus enzymatiques distincts chez les mammifères; la production de l'acide aminée méthionine par la méthionine synthase (MS), et le métabolisme d'acides gras et d'acides aminées par la méthylmalonyl-CoA mutase (MCM). Malgré le fait que les procédées métaboliques intracellulaires de la cobalamine restes peu bien caractérisés, les protéines dont MMACHC, MMADHC, LMBD1, et ABCD4 jouent un rôle dans l'acquisition et le traitement de ce cofacteur. Vu les difficultés intrinsèques de l'utilisation cellulaire de la cobalamine, nous proposons que ces protéines assurent l'efficacité de son canalisation. Cette thèse avait pour objectif de caractériser les interactions protéine-protéine impliquées dans ce processus.Pour pouvoir caractériser la fonction de MMADHC, des isoformes protéiques ont été purifiées et leurs traits structurales ont étés déterminés à basse résolution. MMADHC se trouve à être monomérique et adopte une conformation étendue en solution, avec des régions non structurées dans la terminaison aminée de la protéine. Ensuite, des librairies combinatoires de phages ont été utilisées comme substrats pour tracer des sites d'interactions potentiels avec MMADHC. Les analyses kinésiques des interactions MMACHC–MMADHC ont été faites à l'aide de la résonance plasmonique de surface (SPR) et ont confirmées une intéraction d'affinité sub-micromolaire. Avec ces résultats, nous proposons que la fonction de MMADHC se fasse par sa terminaison acidique en interagissant avec MMACHC dans le cytoplasme.Les phénotypes cliniques et la localisation subcellulaire de MS et de MCM envisagent que MMACHC joue un rôle dans le cytoplasme et que MMADHC se trouve à être impliquée dans le processus au niveau de la mitochondrie et du milieu cytoplasmique. Pour démontrer que l'interaction MMACHC–MMADHC est physiologique, nous avons utilisé l'immunofluorescence et la fractionnement subcellulaire pour confirmer que MMACHC est cytoplasmique et que MMADHC se retrouvent au cytoplasme et au mitochondrie.Des analyses protéiques ont également engendré LMBD1 et ABCD4. Solubilisés à l'aide de détergent, ces deux protéines prennent la conformation d'homodimères en solution. Une interaction d'affinité nanomolaire entre LMBD1 et ABCD4 a été confirmée en SPR. En lien avec nos analyses de phages, MMACHC interagit avec haute affinité avec LMBD1 et ABCD4.Nos résultats supportent un modèle dans lequel LMBD1 et ABCD4, tous deux liés dans la membrane, régularisent l'octroi de la cobalamine lysosomale à MMACHC en prévenant la dilution de ce cofacteur dans le milieu cytoplasmique et en protégeant contre des réactions inactivant. La dissociation et le recrutement de la MMADHC cytoplasmique à MMACHC facilitent le transfert de la cobalamine vers les réactions enzymatiques catalysées par MCM et MS. L'identification et la caractérisation de ces complexes multiprotéiques font en sorte d'avancer nos connaissances générales sur le métabolisme de la cobalamine.
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35

Gibbons, John Marc. "The purification and properties of brain vitamin B12-dependent methionine synthase." Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248228.

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36

Serova, Svetlana. "Association Between Folate, Vitamin B12 and Cognitive Performance in Demented Elderly." Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc9034/.

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Dementia is prevalent among elderly people. As the world population ages, it is projected that the number of people affected by dementia may triple in the next 50 years. Over the last two decades, research has focused on identifying potentially modifiable risk factors in development and progression of dementia, such as vitamin B12 and folate. Results concerning the effects of low folate and vitamin B12 on cognitive performance are mixed. The main objective of the present study was to investigate the effects of vitamin deficiency on cognitive functioning in a clinical sample of elderly individuals with cognitive problems using a comprehensive neuropsychological assessment. A retrospective chart-review was performed on the 102 records of patients from the Geriatrics Clinic at the University of North Texas Health Science Center who presented with cognitive deficits. Charts were reviewed to obtain data on vitamin supplementation, vitamin status, history of chronic conditions and other biochemical data. The available database was used to obtain data on neuropsychological assessment. The study demonstrated mild association between vitamin B12 and folate status and cognitive deficits. There appeared to be a higher cut-off level that is above the traditionally used levels for vitamin B12 and folate deficiency concentrations at which cognitive deficits became more pronounced. Clinical applications, limitations and suggestions for future research were discussed.
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37

Serova, Svetlana Hall James. "Association between folate, vitamin B12 and cognitive performance in demented elderly." [Denton, Tex.] : University of North Texas, 2008. http://digital.library.unt.edu/permalink/meta-dc-9034.

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38

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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39

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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40

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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41

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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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
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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42

Musante, Ashlan M. "The role of mercury speciation in its methylation by methylcobalamin (vitamin-B12) /." Norton, MA : Wheaton College, 2008. http://hdl.handle.net/10090/6024.

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43

Kim, Jaeseung. "Novel inborn error of vitamin B12 metabolism caused by mutations in «ABCD4»." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110521.

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Vitamin B12 (cobalamin, Cbl) is an essential cofactor for two human enzymes: methylmalonyl-CoA mutase (MUT) and methionine synthase (MTR). MUT utilizes 5'-deoxyadenosylcobalamin (AdoCbl) to convert methylmalonyl-CoA to succinyl-CoA in the mitochondria, whereas MTR utilizes methylcobalamin (MeCbl) to convert homocysteine to methionine in the cytoplasm. To date, eight complementation groups (cblA-G and mut), each the result of mutations at a different gene, have been discovered to be involved in the intracellular metabolism of cobalamin. A patient presented at birth, following an abnormal newborn screen, with hypotonia, lethargy, poor feeding and bone marrow suppression. There were elevated levels of methylmalonic acid and homocysteine, suggestive of a defect in vitamin B12 metabolism. Studies of cultured fibroblast showed decreased function of the cobalamin-dependent enzymes, MTR and MUT. There was increased uptake of labelled cyanocobalamin (CNCbl) but decreased synthesis of the cobalamin cofactors MeCbl and AdoCbl, with accumulation of "free" (i.e. non-protein bound) CNCbl in the cells. The cellular phenotype mimicked that of the cblF disorder caused by mutations in the LMBRD1 gene encoding the lysosomal membrane protein LMBD1 that is thought to play a role in transfer of cobalamin across the lysosomal membrane into the cytoplasm. However, cells from the patient complemented those from all known complementation groups, including cblF, and no mutations in LMBRD1 were found. Whole-exome sequencing led to the identification of two mutations in the ABCD4 gene: c.956A>G (p.Y319C) and c.1746_1747insCT (p.E583LfsX9). Two additional patients with deleterious ABCD4 mutations were later found. Transfection of patient fibroblasts with wild type ABCD4 led to rescue of all abnormal cellular phenotypes. This thesis reports that this novel disorder, named cblJ, is an autosomal recessive disorder caused by mutations in ABCD4. The findings suggest that ABCD4, an ABC half-transporter, is another essential component of intracellular cobalamin metabolism.
La vitamine B12 (cobalamine, Cbl) est un cofacteur essentiel pour deux enzymes de l'homme: la méthylmalonyl-CoA mutase (MUT) et la méthionine synthase (MTR). La MUT utilise 5'-deoxyadenosylcobalamin (AdoCbl) pour convertir la méthylmalonyl-CoA en succinyl-CoA dans la mitochondrie, alors que MTR utilise la méthylcobalamine (MeCbl) pour convertir l'homocystéine en méthionine dans le cytoplasme. À ce jour, huit groupes de complémentation (cblA-G et mut) ont été découverts à être impliqués dans le métabolisme intracellulaire de la cobalamine. Chacun est le résultat de mutations au niveau d'un gène différent. Un patient s'est présenté à la naissance, suite à une anomalie sue le dépistage nouveau-né, avec l'hypotonie, la léthargie, la mauvaise alimentation et la suppression de la moelle osseuse. Le patient avait des niveaux élevés d'acide méthylmalonique et d'homocystéine, suggérant un défaut dans le métabolisme de la vitamine B12. Les études de fibroblastes cultivés ont démontré une diminution de la fonction des enzymes dépendants sur la cobalamine, MTR et MUT. Il avait aussi une augmentation de l'absorption de la cyanocobalamine (CNCbl), mais une diminution de la synthèse de cofacteurs cobalamine la MeCbl et AdoCbl, avec une accumulation de CNCbl "libre" (c'est à dire non liée aux protéines plasmatiques) dans les cellules. Le phénotype cellulaire imitait celle de la maladie cblF, causée par des mutations dans LMBRD1, le gène codant pour la protéine membrane lysosomale LMBRD1, qui semble jouer un rôle dans le transfert de la cobalamine à travers la membrane lysosomale dans le cytoplasme. Cependant, les cellules des deux patients complémentaient celles de tous les groupes de complémentation connus, y compris cblF, et aucune des mutations dans LMBRD1 ont été trouvés. Le séquençage de l'exome a mené à l'identification de deux mutations dans le gène ABCD4: c.956A>G (p.Y319C) et c.1746_1747insCT (p.E583LfsX9). Deux autres patients avec des mutations dans ABCD4 ont été retrouvés. Toutes les mutations ont été prévues d'être nocives. La transfection de fibroblastes de patients avec ABCD4 de type sauvage a conduit à sauver tous les phénotypes cellulaires anormaux. Cette thèse rapporte que ce trouble inédit, nommé cblJ, est une maladie autosomique récessive causée par des mutations dans ABCD4. Les résultats suggèrent qu'ABCD4, un demi-ABC transporteur, est un autre élément essentiel du métabolisme de la cobalamine intracellulaire.
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44

Zhang, Zhong Da. "Asymmetric catalysis by vitamin B12 : the isomerization of Achiral epoxides and Aziridines /." [S.l.] : [s.n.], 1992. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.

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45

Leech, Helen Kirsty. "The biosynthesis of sirohydrochlorin and its transformation into sirohaem and vitamin B12." Thesis, Queen Mary, University of London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408660.

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46

Kysil, Olga Aleksandrovna [Verfasser]. "Grundlegende Untersuchungen zur mikrobiellen Synthese von Vitamin B12 in symbiotischen pflanzlichen Systemen am Beispiel der Frankia : Entwicklung neuartiger pflanzlicher Extrakte mit hohem essentiellen Vitamin B12-Gehalt / Olga Aleksandrovna Kysil." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2014. http://d-nb.info/1053416199/34.

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47

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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Coordenação 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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48

Zainuddin, Zarina. "Expression of vitamin B₁₂ enzymes in Chlamydomonas reinhardtii chloroplast." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609492.

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49

Aljaadi, Abeer Mohammad. "Programming of hepatic gene expression by maternal folic acid and vitamin B12 imbalance." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50038.

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Folate is a B-vitamin required for cell growth and division, and its metabolism is linked to vitamin B12 (B12). Food fortification with folic acid (FA) has improved folate status but approximately 5% of Canadian adults, including pregnant women, are B12 deficient. This is concerning because an association between gestational exposure to high maternal folate and low B12 status and greater adiposity and insulin resistance in children has been reported. My thesis examined the effect of developmental exposure to maternal FA/B12 imbalance on programming of liver gene expression in adult offspring using an animal model. Female C57BL/6 mice were fed a high FA/adequate B12 (HFA+B12), high FA/no B12 (HFA-B12), or control diet 6 weeks prior to mating and through pregnancy and lactation. At weaning, offspring mice from each maternal diet group were randomly assigned to receive the control diet or a Western diet (45% fat, 35% carbohydrate) for 20 weeks (n=6 male mice/group) or for 40 weeks (n=6 female mice/group). Serum folate and B12 concentrations were quantified by microbiological assays. Relative mRNA expression of key enzymes in methyl metabolism in liver from adult offspring was quantified by real-time PCR. Male offspring mice from dams fed the HFA-B12 diet had lower Cbs and Mthfr mRNA expression and this was unaffected by post weaning diet. Male offspring mice fed the Western diet had higher Mtr mRNA expression compared to control-fed offspring mice, regardless of maternal diet. Female offspring from dams fed the HFA-B12 diet had lower Mtr mRNA expression and this was not affected by post weaning diet. Moreover, female offspring from dams fed the HFA-B12 diet had higher Mthfr mRNA expression when they were fed the Western diet. No effect of maternal and post weaning diets was observed for serum folate and B12 concentrations. In summary, developmental exposure to maternal FA/B12 imbalance was found to program expression of genes involved in folate and methionine metabolism in the liver of adult offspring mice. The functional consequences of this effect requires further investigation in order to consider B12 screening of pregnant women and to inform the debate on whether B12 fortification should be considered.
Land and Food Systems, Faculty of
Graduate
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50

Lewerin, Catharina. "Vitamin B12 and folate depletion in the elderly : diagnosis, clinical correlates and causes /." Göteborg : Section of Haematology and Coagulation, Dept. of Internal Medicine at The Sahlgrnska Academy, Göteborg University, 2006. http://hdl.handle.net/2077/741.

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