Dissertations / Theses: 'Vitamin B1'

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Tanja, Brezo-Borjan. "Određivanje vitamina B1, B2 i B3 primenom hronopotenciometrije i hronopotenciometrijske striping analize." Phd thesis, Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, 2019. https://www.cris.uns.ac.rs/record.jsf?recordId=111000&source=NDLTD&language=en.

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U okviru ove doktorske disertacije razvijene su elektroanalitičke metode za određivanje pojedinih vitamina B grupe. Za određivanje vitamina B₁ i B₃ primenjena je adsorpciona hronopotenciometrijska striping analiza (AdHSA) na tankoslojnoj živinoj elektrodi kao radnoj elektrodi, dok je za određivanje vitamina B2 primenjena hronopotenciometrijska analiza (HA) na dvema geometrijski različitim elektrodama od staklastog ugljenika: planarnoj disk elektrodi i elektrodi u vidu procesne posude. U cilju optimizacije metoda ispitan je uticaj najznačajnijih eksperimentalnih faktora. Optimalni eksperimentalni uslovi za određivanje vitamina B₁ su podrazumevali primenu 0,2 mol/l citratnog pufera vrednosti pH 6 kao pomoćnog elektrolita, potencijala i vremena akumulacije od -1,313 V i 50 s, redom, i struje rastvaranja depozita od 1,9 – 6,1 μA. Odgovarajući eksperimentalni faktori za određivanje vitamina B₂ su bili: 0,025 mol/l HCl kao pomoćni elektrolit, inicijalni potencijal od 0,023 V i struja redukcije od 0,8 – 4,2 μA, dok su optimalni radni uslovi za određivanje vitamina B₃ obuhvatali primenu 0,05 mol/l citratnog pufera pH 6, potencijala akumulacije od -1,405 V pri vremenu akumulacije od 15 s, i struji rastvaranja u intervalu od 1,4 – 15,1 μA. U slučaju određivanja vitamina B₂ primenom radne elektrode u vidu procesne posude ispitan je i uticaj aktivne površine radne elektrode na analitički signal vitamina B₂. Optimalna vrednost aktivne površine radne elektrode iznosila je 13,4 cm². Pod optimalnim eksperimentalnim uslovima, dolazilo je do elektrooksidacije molekula vitamina B₁ i B₃ na tankoslojnoj živinoj elektrodi u analitičkom koraku, dok se vitamin B₂ redukovao na elektrodama od staklastog ugljenika. U okviru validacije metoda definisani su opsezi linearnosti, određene su vrednosti granice detekcije i granice kvantitativnog određivanja, ocenjena je preciznost i ispitane su interferencije. Uz odgovarajuće uslove rada, dobijena je dobra linearnost analitičkog signala od sadržaja za sva tri ispitivana vitamina. Ostvarene su granice detekcije od 1,64 mg/l za vitamin B₁, 0,076 mg/l za vitamin B₂ uz primenu planarne disk elektrode i 0,018 mg/l (vitamin B₂) uz primenu procesne posude od staklastog ugljenika kao radne elektrode. Ostvarena granica detekcije za vitamin B₃ je iznosila 2,20 mg/l. Nakon optimizacije i validacije, razvijene metode HA i AdHSA primenjene su za određivanje vitamina B₁, B₂ i B₃ u komercijalnim multivitaminskim dodacima ishrani i multivitaminskim instant napicima. Tačnost razvijenih metoda je potvrđena paralelnim analizama izvedenim primenom visokopritisne tečne hromatografije.
Within the scope of this doctoral dissertation, electroanalytical methods for the determination of several vitamins of the B-complex are developed. For the determination of vitamin B1 and B3 adsorptive chronopotentiometric stripping analysis was applied, with mercury film electrode as the working electrode. For vitamin B2 determination, the chronopotentiometric analysis was performed on two geometrically different glassy carbon working electrodes: the planar disc electrode and the process vessel electrode. The most important experimental parameters of the analysis were investigated and optimized. For vitamin B₁ determination, the optimized experimental conditions were: 0,2 mol/l citrate buffer pH 6 as the supporting electrolyte, accumulation potential of -1,313 V, accumulation time of 15 s and the oxidation current between 1,9 μA and 6,1 μA. The appropriate experimental factors for vitamin B₂ determination included 0,025 mol/l HCl solution (supporting electrolyte), initial potential of 0,023 V and reduction current in the range from 0,8 – 4,2 μA, whereas the optimal working parameters for vitamin B3 determination were as follows:0,05 mol/l citrate buffer pH 6, accumulation potential of -1,405 V, accumulation time of 15 s and dissolution current from 1.4 – 15.1 μA. When the process vessel was used as the working electrode, the optimal volume of the analyzed solution i.e. the active surface area of the electrode was optimized. The optimal value of the active surface area was 13,4 cm2. As well, under the optimal experimental conditions, vitamin B₁ and vitamin B3 underwent electrooxidation process in the analytical step, whereas vitamin B₂ was electrochemically reduced on glassy carbon electrodes. A validation procedure of the optimized methods was performed by evaluation of the following parameters: linearity, the limit of detection (LOD), the limit of quantitation (LOQ), precision, selectivity, and accuracy. Under optimal working conditions, the linearity of the proposed methods was very good. The achieved limits of detection were 1.64 mg/l for vitamin B₁, 0,076 mg/l for vitamin B₂ (planar disc electrode) and 0,018 mg/l (process vessel electrode) and 2,2 mg/l for vitamin B₃.After optimization and validation procedures, the developed methods were applied for vitamin B₁, B₂, and vitamin B₃ determination in commercially available multivitamin supplements and instant multivitamin beverages. The accuracy of the proposed methods was tested by parallel HPLC analyses of the same samples.

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Jordão, Fabiana Morandi. "Caracterização bioquímica da biossíntese de tiamina (vitamina B1) em Plasmodium falciparum." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/42/42135/tde-18102007-151045/.

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Nesta dissertação, foi caracterizada a via de biossíntese de tiamina (Vitamina B1) nas três formas intraeritrocitárias de P. falciparum. Foram realizadas marcações metabólicas, utilizando diferentes precursores radioativos envolvidos na biossíntese de tiamina, já descritos para outros organismos. A utilização do precursor [1-14C] acetato de sódio demonstrou que a via de biossíntese de tiamina encontra-se ativa em todos os estágios intraeritrocitários de P. falciparum. Investigamos os precursores que poderiam estar envolvidos na biossíntese do intermediário tiazol, e nossos dados sugerem que a cistéina é a doadora do enxofre presente na molécula de tiamina; que o aminoácido tirosina pode ser o precursor da biossíntese de tiamina, e nicotinamida não é utilizada como precursor em P. falciparum. Também se avaliou o efeito da fosmidomicina e 3ClDHP e foi demonstrado que ambos propiciaram uma inibição no crescimento dos parasitas. Estes dados sugerem que a via de biossíntese de tiamina, pode ser explorada como alvo para drogas antimaláricas, devido ausência em humanos.
In the present work we have demonstrated the biosynthesis of thiamin (vitamin B1) in the intraerytrocytic stages of P. falciparum. We have demonstrated active biosynthesis of thiamine in the three parasite stages metabolically labeled with [1-14C] sodium acetate. We also investigated which precursors could be involved in the biosynthesis of the thiazole intermediate, by metabolic labelling with different precursors. Our data suggest that the sulphur present in the thiamine molecule is formed from cysteine white that tyrosine can be the precursor of thiamine biosynthesis. Nicotinamide is not utilized as a precursor in P.falciparum. We also investigated the effect of fosmidomycin (an inhibitor of the DOXP reductoisomerase in the MEP pathway) and 3CIDHP (an analogue of bacimethrin) in vitro cultures and both showed an inhibitory effect on parasite growth. These data suggest that the biosynthesis of thiamine can be an attractive target for the development of antimalarial drugs since this pathway is absent in humans.

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Balia, Yusof Zetty Norhana. "Regulation of thiamine biosynthesis in Chlamydomonas reinhardtii." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610616.

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Ajjawi, Imad. "Thiamin synthesis and cofactor activation in Arabidopsis thaliana /." abstract and full text PDF (free order & download UNR users only), 2006. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3250683.

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Thesis (Ph. D.)--University of Nevada, Reno, 2006.
"December 2006." Includes bibliographical references. Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2006]. 1 microfilm reel ; 35 mm.

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Häubner, Norbert. "Dynamics of astaxanthin, tocopherol (Vitamin E) and thiamine (Vitamin B1) in the Baltic Sea ecosystem : Bottom-up effects in an aquatic food web." Doctoral thesis, Uppsala universitet, Ekologisk botanik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-130143.

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The thesis combines laboratory experiments and field expeditions to study production, transfer and consumption of non-enzymatic antioxidants and thiamine in an aquatic food web. In particular, I (1) documented spatial and seasonal variation of tocopherols and carotenoids in the Baltic Sea pelagic food web, and (2) examined the effects of abiotic and biotic factors on tocopherol, carotenoid and thiamine concentrations in phytoplankton, zooplankton and fish. Moderate differences in temperature and salinity affected α-tocopherol, β-carotene and thiamine production in microalgae. Furthermore, the results suggest that acute stress favors the expression of non-enzymatic antioxidants rather than enzymatic antioxidants. Because production of α-tocopherol, β-carotene and thiamine differ markedly between microalgae, the availability of non-enzymatic antioxidants and thiamine is likely to be highly variable in the Baltic Sea and is difficult to predict. The transfer of non-enzymatic antioxidants from phytoplankton to zooplankton was biomass dependent. The field expeditions revealed that phytoplankton biomass was negatively associated with α-tocopherol concentration in mesozooplankton. Thus, increased eutrophication of the Baltic Sea followed by an increase in phytoplankton biomass could decrease the transfer of essential biochemicals to higher levels in the pelagic food web. This could lead to deficiency syndromes, of the kind already observed in the Baltic Sea. Astaxanthin is synthesized from precursors provided by the phytoplankton community. Thus biomass dependent transfer of astaxanthin precursors from phytoplankton to zooplankton could be responsible for astaxanthin deficiency in zooplanktivorous herring. Astaxanthin in herring consists mostly of all-Z-isomers, which are characterized by low bioavailability. Therefore, astaxanthin deficiency in salmon could be explained by the low concentration of this substance and its isomeric composition in herring.

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Sylvander, Peter. "Thiamine dynamics in the pelagic food web of the Baltic Sea." Doctoral thesis, Stockholms universitet, Institutionen för ekologi, miljö och botanik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-89192.

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Thiamine (vitamin B1) is involved in several basal metabolic processes. It is an essential compound for many organisms and in aquatic systems it is mainly produced by phytoplankton and prokaryotes and transferred to higher trophic levels through grazing and predation. The occurrence of thiamine deficiency in top predators has been reported from several aquatic systems. In the Baltic populations of the Atlantic salmon (Salmo salar) this has been observed since 1974 and recently thiamine deficiency has also been reported for Baltic sea birds. This thesis aims at investigating what processes that governs the flow of thiamine from the primary producers to top predators via zooplankton grazers and planktivoric fish. Paper I showed that abiotic stress factors such as salinity, temperature and light conditions can alter the thiamine content of phytoplankton. Paper II showed that abiotic factors indirectly can affect the stress resistance of zooplankton grazers by changing the nutritional quality of their food. In Paper III we found that the in situ thiamine content of zooplankton grazers was directly affected by that of the phytoplankton diet. In Paper IV we found a similar connection between the thiamine contents of Baltic salmon and herring, one of the major salmon prey species. In Paper V we looked at the thiamine content of the pelagic food web of the Baltic Sea as a whole and found a pattern of trophic dilution; the higher the trophic level of an organism (i.e. the further away from the source of thiamine in the food web), the lower was its thiamine content. In all, the results of this thesis suggests a bottom up effect on the thiamine status of the higher trophic levels of the Baltic Sea and that external factors, both natural and man-made, have the capability to affect the thiamine status of the plankton communities and thereby the whole Baltic ecosystem. Thiamine and other micronutrients are not something generally considered in the environmental management of aquatic systems but the results of this thesis suggest that ecological disturbances indirectly can have negative effects on top predators via a disrupted supply of essential substances.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript. Paper 5: Manuscript.

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Tunc, Meral. "The molecular genetic regulation of thiamin biosynthesis in plants." abstract and full text PDF (free order & download UNR users only), 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3307578.

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Beauvais, Maxime. "Long term seasonality of microbial vitamin B1 and B12 metabolisms and their potential interplay in the Northwestern Mediterranean Sea." Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS641.

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L'environnement façonne les communautés microbiennes qui dirigent les cycles biogéochimiques des océans, mais les facteurs biotiques sont également d’important déterminants dans la structure des communautés. Ces systèmes dynamiques sont composés d'espèces cooccurrentes structurées dans un réseau complexe d'interactions entre organismes et avec leur environnement. Les vitamines B1 et B12 sont des cofacteurs essentiels mais la plupart des microbes marins incluant de nombreuses espèces de phytoplancton, ne peuvent pas les produire eux-mêmes (auxotrophes aux vitamines). De plus, les vitamines B1 et B12 sont rares dans l’océan. Ensemble, ces observations soulèvent la question suivante : comment les auxotrophes assurent-ils leurs besoins en vitamines dans l’océan ? Cette question reste en grande partie sans réponse car la saisonnalité des auxotrophes et leur interaction avec les producteurs de vitamines restent peu étudiées. Pour combler ces lacunes, nous avons réalisé une série temporelle métagénomique mensuelle sur 7 ans dans un site côtier de Méditerranée Nord-Ouest (station SOLA) afin d'évaluer la saisonnalité à long terme des communautés procaryotes, en se focalisant sur les métabolismes des vitamines B1 et B12 et leur interaction potentielle au cours des saisons. Tout d'abord, nous avons mis en évidence une succession saisonnière de différents organismes pouvant utiliser des voies distinctes pour produire de la B12 tout au long de l'année. En été, les bactéries du genre HIMB11, UBA8309 et Puniceispirillum peuvent utiliser la voie de production aérobie, tandis qu'en hiver, les archées du genre Nitrosopumilus et Nitrosopelagicus peuvent utiliser la voie de production anaérobie. Ensuite, nous avons montré que lors de perturbations environnementales, les organismes habituellement porteurs de gènes de synthèse de la B12 sont remplacés par d'autres porteurs du même gène (redondance fonctionnelle), maintenant ainsi le potentiel de production de B12. Cette assurance écologique pourrait contribuer à la résilience fonctionnelle à long terme des communautés microbiennes marines exposées à des conditions environnementales interannuelles contrastées. Deuxièmement, nous avons montré que les communautés procaryotes à SOLA étaient dominées par des auxotrophes HMP (Pelagibacter), dont l'abondance était plus élevée en été avec d’autre auxotrophes plus rares (doubles HET/HMP, comme HIMB59), et par des auxotrophes B1 (HIMB11), qui étaient présents tout au long de l'année. À SOLA, nous avons rapporté une plus grande contribution des producteurs de B1 que précédemment observé dans d'autres régions, incluant des bactéries (Pseudothioglobus, MB11C04), des cyanobactéries (Synechococcus) et des archées (Nitrosopumilus). Les expériences de bio-essais ont montré de multiples périodes de limitation en vitamines et précurseurs dans l'eau de mer pendant les mois d'hiver. En outre, l'ajout de vitamines et de précurseurs a eu un impact significatif sur la structure de la communauté procaryote dans nos microcosmes, en particulier en Février. Différents ASV ont été sélectivement favorisés par différentes conditions pendant la transition hiver/printemps. Cependant, la réponse des communautés reste difficile à démêler sachant que les auxotrophes et les prototrophes sont impactés par l’ajout de vitamines/précurseurs. Enfin, grâce à l’assemblage de MAGs et en identifiant leurs potentiels de production pour la B1 et la B12, nous avons montré des schémas de cooccurrence forts et récurrents entre les auxotrophes et les producteurs de vitamines, reflétant différentes complémentarités fonctionnelles potentielles en fonction des saisons. La double complémentarité pour la B1 et la B12 était prédominante dans le réseau de cooccurrence d’été (un auxotrophe B1/B12 avec un prototrophe B1/B12), tandis que la simple complémentarité pour la B1 ou la B12 était prédominante dans les cooccurrences d'hiver (un auxotrophe B1/producteur de B12 avec un producteur de B1/auxotrophe B12)
The environment shapes marine microbial assemblages that drive ocean biogeochemical cycles, but biotic interactions are also strong community structuring factors. Marine microbial communities are dynamic systems of co-occurring species structured as a complex network of interactions, including microbe to environment and microbe to microbe connections. B-vitamins are essential cofactors of critical cellular processes, and most marine microbes, including many phytoplankton species require an exogenous source of vitamins or precursors to grow (i.e., vitamin or precursor auxotrophs). Despite their ecological importance, B1 and B12 are scarce in most oceanic and coastal regions. Together, the widespread vitamin scarcity observed in oceans and the high incidence of vitamin auxotrophy raises the question of how vitamin auxotrophs ensure their vitamin requirements in a large and diluted environment? This question remains largely unanswered as the seasonality of vitamin auxotrophs and their interplay with vitamin producers remain poorly studied. To tackle these knowledge gaps, we conducted a 7 years monthly metagenomic time series in the coastal NW Mediterranean Sea (SOLA station) to assess the long-term seasonality of planktonic prokaryotic communities, with a focus on B1 and B12 metabolisms and their potential interplay over time.First, we highlighted a seasonal succession of different organisms which could use distinct biosynthesis pathways to produce B12 de-novo along the year. In summer, bacteria belonging to the genera HIMB11, UBA8309 and Puniceispirillum could use the aerobic B12 production pathway, while in winter, Thaumarchaeota belonging to Nitrosopumilus and Nitrosopelagicus genera could use the anaerobic B12 production pathway. Then, we show that during irregular environmental perturbations observed in winter at SOLA station, organisms usually carrying B12 synthesis genes are replaced by others with the same gene (i.e., functional redundancy), thus maintaining the potential for B12 production. Such ecological insurance could contribute to the long-term functional resilience of marine microbial communities exposed to contrasting inter-annual environmental conditions. Secondly, we showed that SOLA prokaryotic communities were dominated by HMP auxotrophs (Pelagibacter, AAA536-G10, Litoricola), which had higher abundances in summer together with the rarer dual HET/HMP auxotrophs (HIMB59, HIMB100, Octadecabacter), and by B1 auxotrophs (HIMB11, Puniceispirillum), which were present throughout the year. At SOLA, we reported a larger contribution of B1 producers than previously reported in other regions, including bacteria (Pseudothioglobus, MB11C04), cyanobacteria (Synechococcus, Prochlorococcus) and archaea (Nitrosopumilus, Nitrosopelagicus). Bioassays experiments using showed multiple vitamin and precursor limitations periods in SOLA seawater during winter months. Moreover, the addition of vitamins and precursors had a significant impact on prokaryotic community structure in our microcosm’s experiments, especially in February. Different ASVs were selectively promoted by different conditions during the winter/spring transition (B12, H+C and B1+B12). However, the differential response of communities remains difficult to disentangle, given that both vitamin auxotrophs and prototrophs were promoted during our incubations. Finally, by assembling high-quality metagenome assembled genomes (MAGs) and identifying their B1 and B12 lifestyles, we highlight strong and recurrent co-occurrence patterns between vitamin auxotrophs and producers reflecting different potential functional complementarities between them depending on the season. Double complementarity for B1 and for B12 was prevalent in summer co-occurrences networks (e.g., B1/B12 auxotroph co-occur with B1/B12 prototroph), while simple complementarity for B1 or B12 was prevalent in winter co-occurrences (e.g., B1 auxotroph / B12 producer co-occur with B1 producer/B12 auxotroph)

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Künz, Madeleine [Verfasser], and Christian [Akademischer Betreuer] Betzel. "Investigations on an Innovative Antibiotic Approach : Structure-Function-Analysis of Essential Enzymes Routing the Vitamin B1 de novo Biosynthesis and Vitamin B6 Salvage Pathway of Staphylococcus aureus / Madeleine Künz. Betreuer: Christian Betzel." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2015. http://d-nb.info/1075317398/34.

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Roland, Jessica Justine. "Septohippocampal system modulation in an animal model of diencephalic amnesia." Diss., Online access via UMI:, 2008.

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Anzalone, Steven J. "Cholinergic cortical dysfunction in an animal model of diencephalic amnesia." Diss., Online access via UMI:, 2009.

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Page, Georgina L. J. "Oral thiamine (Vitamin B1) supplementation in subjects with type 2 diabetes mellitus : a randomised, double-blind, placebo-controlled crossover trial assessing biophysical markers of endothelial function, oxidant stress, insulin sensitivity and vascular inflammation." Thesis, University of Portsmouth, 2013. https://researchportal.port.ac.uk/portal/en/theses/oral-thiamine-vitamin-b1-supplementation-in-subjects-with-type-2-diabetes-mellitus(aac28b07-c232-4bc6-baed-4cbcb0531efa).html.

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Background and Aims Type 2 diabetes is increasing in prevalence and is associated with a threefold increased risk of cardiovascular mortality despite management of the traditional risk factors. Novel risk factors have been hypothesised that contribute to the pathogenesis of both type 2 diabetes and atherosclerosis and include oxidative stress, inflammation and endothelial dysfunction. Thiamine has been shown to be an important cofactor in the attenuation of these novel risk factors and people with type 2 diabetes have been shown to be thiamine deficient. This study tested the hypothesis that thiamine supplementation may improve endothelial function, oxidative stress, vascular inflammation and insulin resistance in subjects with type 2 diabetes who have a high cardiovascular risk profile. Methods Subjects with type 2 diabetes underwent a randomised, double blind, placebo-‐controlled crossover pilot study receiving 300mg daily of oral thiamine hydrochloride or placebo for eight weeks with a two week washout period. Measurements were taken for endothelial function (change in the reflective index post salbutamol using digital photoplethysmography, plasma cyclic GMP, plasma sVCAM-‐1, urinary albumin: creatinine ratio), insulin resistance (HOMA-‐IR), oxidative stress (glutathione ratio, CuPRAC-BCS) and inflammation (hsCRP) at the beginning and end of treatment with both thiamine and placebo. Results 34 patients (20 male) completed the study. Mean age 61 ± 9.4 years, HbA1c 7.46 ± 0.88%, blood pressure 137/77 ± 18/9 mmHg, total cholesterol 4.01 ± 1.11 mmol/l, HDL cholesterol 1.00 ± 0.30 mmol/l, triglycerides 1.87 ± 1.39 3 mmol/l. The majority of the patients were on two or more glucose lowering therapies with 88% on metformin. Most of the patients were on other cardiovascular disease modifying medications (statins or antihypertensive agents). Treatment with thiamine demonstrated a significant increase in thiamine diphosphate levels (310 ± 82 nmol/l post thiamine vs. 178 ± 32 nmol/l post placebo, p=<0.001) but no significant difference in markers of endothelial function, insulin resistance, oxidative stress or inflammation or other metabolic markers. Conclusion In this cohort of patients treatment with 300mg per day of oral thiamine for eight weeks in well-‐controlled type 2 diabetes at high cardiovascular risk, demonstrated no significant improvement in endothelial function, insulin resistance, oxidative stress or inflammation.

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Kozel, Carrie L. "Early Feeding In Lake Trout Fry (salvelinus Namaycush) As A Mechanism For Ameliorating Thiamine Deficiency Complex." ScholarWorks @ UVM, 2017. http://scholarworks.uvm.edu/graddis/685.

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Recruitment failure of lake trout (Salvelinus namaycush) in the Great Lakes has been attributed in part to the consumption of alewife (Alosa pseudoharengus) by adult lake trout, leading to Thiamine Deficiency Complex (TDC) and early mortality in fry. The current understanding of thiamine deficiency in lake trout fry is based on information from culture and hatchery settings, which do not represent conditions fry experience in the wild and may influence the occurrence of TDC. In the wild, lake trout fry have access to zooplankton immediately following hatching; previous studies found that wild fry begin feeding before complete yolk-sac absorption. However, hatchery-raised fry are not provided with food until after yolk-sac absorption, long after the development of TDC. Zooplankton are a potential source of dietary thiamine for wild fry in the early life stages that has not previously been considered in the occurrence of thiamine deficiency. We postulated that wild-hatched fry could mitigate thiamine deficiency through early feeding on natural prey. Specifically, we hypothesized 1) feeding should increase thiamine concentrations relative to unfed fry and 2) feeding should increase survival relative to unfed fry. Feeding experiments were conducted on lake trout fry reared from eggs collected from Lake Champlain in 2014 and Cayuga Lake in 2015. A fully crossed experimental design was used to determine the effect of early feeding by lake trout fry in thiamine replete and thiamine deplete treatments before and after feeding. Overall, thiamine concentrations and survival did not significantly differ between fed and unfed fry. Thiamine concentrations increased from egg stage to hatching in both years, suggesting a potential source of thiamine, which had not previously been considered, was available to the lake trout eggs during development.

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Ribeiro, Fernando Augusto de Oliveira. "Efeito neurodegenerativos causados pela deficiência de vitamina B1." Universidade Federal de Minas Gerais, 2006. http://hdl.handle.net/1843/MCSC-78AT2E.

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Oxidative stress, selective neuronal loss, and diminished activity of thiaminedependent enzymes is assumed to characterize most of the neurodegenerative diseases. Thiamine deficiency (TD) models have been used to produce selective neurodegeneration basically because of the mild impairment of oxidative metabolism. In the present study, we report that TD elicited a significant decrease in voltage-dependent K+ membrane conductance in cerebellar granule neurons. We examined the TD effects on delayed rectifier and A-type K+ channels, two well known voltage-activated K+ channels involved in the regulation of action potential firing in cerebellar granule neurons. Current recordings were performed in cultured rat cerebellar granule neurons using the whole-cell voltageclamp technique. TD markedly depressed the transient A-type K+ currents. The present results suggest that, by inhibiting IA, there is increase in action potential firing. Both situations could cause neuronal cell death.
Estresse oxidativo, perda neuronial seletiva, e a atividade diminuída de enzimas dependentes de tiamina parecem provocar a maioria das doenças neurodegenerativas. Os modelos da deficiência de tiamina (DT) são usados para produzir neurodegeneração seletiva por causa do comprometimento do metabolismo oxidativo. No estudo atual, nós relatamos que a DT revelou uma diminuição significativa na condutância, tempo-dependente, de membrana para as correntes de K+ nos neurônios granulares do cerebelo. Nós examinamos os efeitos da DT sobre os canais para K+ sensíveis a voltagem do tipo retificadorretardado e do tipo-A, os quais estão envolvidos na regulação e disparo de potenciais de ação nos neurônios granulares. Os registros foram feitos em neurônios cerebelares usando a técnica da whole-cell voltage e current-clamp. A DT diminuiu as correntes de K+, inibindo primariamente a IA, e aumentou a freqüência de despolarizações. Os conjuntos destas mudanças poderiam levar a morte neuronial.

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CARCEL, CORINNE. "Indications du dosage sanguin de la vitamine b1 : etude retrospective concernant 5359 dosages." Lyon 1, 1989. http://www.theses.fr/1989LYO1M404.

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Agostini, Tania da Silveira. "Desenvolvimento de metodologia para determinação simultanea, por CLAE das vitaminas B1, B2, B6, acido nicotinico e nicotinamida em alimentos enriquecidos." [s.n.], 1993. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254285.

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Orientador: Helena Teixeira Godoy
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O controle dos níveis de enriquecimento de alimentos, pela adição de vitaminas, tem sido dificultado, especialmente, pela falta de metodologias apropriadas. Visando suprir esta deficiência, foi desenvolvida e. avaliada uma metodologia para determinação simultânea das vitaminas B1, B2, B6, ácido nicotínico e nicotinamida em alimentos enriquecidos, utilizando a cromatografia líquida de alta eficiência (CLAE). O método desenvolvido foi aplicado na determinação dessas vitaminas em 50 diferentes tipos/marcas de alimentos enriquecidos, como biscoitos de maisena (marca comercial grafada com Z, registrada), de leite, maria, coco e recheados, farinhas de cereais, farinhas lácteas, flocos de milho, macarrões, bebidas lácteas aromatizadas, leite em pó e esterilizado, bebida dietética e um complemento alimentar para desenvolvimento de massa muscular. As vantagens do método proposto, em relação aos métodos oficiais, são, além da determinação simultânea de 4 vitaminas (Bl, B2, B6 e PP, incluindo as duas formas desta última, ácido nicotínico e nicotinamida), simplicidade e versatilidade das etapas de extração e limpeza, utilização de reagentes com menores níveis de toxicidade, uso de detector UV, em substituição ao de fluorescência, eliminação de reações de derivação e rapidez. A extração multivitamínica é feita com ácido sulfúrico diluído, através de vibração ultra-sônica. A precipitação do extrato com metanol, seguida de refrigeração, é satisfatória tanto na eliminação de interferentes, quanto na prevenção de precipitação na coluna cromatográfica. A eluição por gradiente é importante para a obtenção de boa resolução das vitaminas, sendo que todas as vitaminas são eluídas em 23 min de corrida. O tempo necessário para o re-equilíbrio da coluna é de 20 mino A detecção é feita na região do ultravioleta e a quantificação é feita por curvas de padronização externa. Os limites de detecção e recuperação, nos níveis médios de enriquecimento, foram, respectivamente, 0,04 µg/ml e 102% para a vitamina B1, 0,03 µg/ml e 96% para a B2, 0,08 µg/ml e 106% para a B6, 0,10 µg/ml e 105% para a nicotinamida e 0.03 µg/ml e 81% para o ácido nicotínico. Os testes de repetibilidade, nos níveis de enriquecimento, apresentaram um coeficiente de variação médio inferior a 5% para as vitaminas B1, B2 e nicotinamida, inferior a 10% para a vitamina B6 e inferior a 13% para o ácido nicotínico. Entre os alimentos enriquecidos analisados, todos os diferentes tipos de biscoitos, de 1 única marca, apresentaram apenas 30 % dos valores de vitamina B2 descritos nas embalagens dos produtos; os flocos de milho, de 4 diferentes marcas, apresentaram menos de 30% dos níveis vitamínicos declarados; macarrões, de 1 única marca, não apresentaram nenhuma das vitaminas descritas nas embalagens do produto e o complemento alimentar para desenvolvimento de massa muscular apresentou níveis de B1, B2 e nicotinamida superiores a 300% dos valores declarados. Menores variações também foram observadas em alguns dos outros produtos analisados. Os resultados obtidos neste trabalho, além de demonstrarem as vantagens e aplicabilidade da metodologia desenvolvida, apontam para a necessidade de maior rigor no controle das taxas de enriquecimento destes alimentos.
Abstract:The control of enrichment levels in foods is difficult mainly due to the lack of appropriate analytical methodology. A new method for the simultaneous determination of nicotinamide, nicotinic acid, ribotlavin, thiamin and pyridoxine in enriched Brazilian foods by high performance liquid chromatography (HPLC) was developed and evaluated. The new method was employed to determine the vitamin B group in a survey of fifty products, such as cornflour, milk, coconut and sandwich biscuits, cereal flour, lacteous flours, com flakes, macaroni, flavored milk, whole and skim milk powder, acidified milk powder, steritized whole milk, flavored diet drinks and flavored mix for milk-based diet drink. In addition to the simultaneous determination of four vitamins (Bl, B2, B6 and two diferent forms of PP), the advantages of the method developed are: simplicity and improvement in the extraction and cleaning procedures, no use of toxic reagents, use of the UV detector instead of the fluorescent detector, elimination of derivatization reactions and speed in comparison with the official methods. The multivitamin extraction with sulfuric acid in an ultrasonic wave vibrator proved effective. The methanol solution provided partial purification of the extract and prevented precipitation on the analytical column. Neverthless, a gradient elution was necessary in order to get good resolution of the compounds. As the amounts of vitamins in enriched foods are normally greater than usual, the detection can be made using a UV detector. Quantitative data were obtained using calibration curves constructed by plotting peak area versus concentration. Quantification limits of the method and recoveries, in average enrichment levels, were 0.04 µg/ml and 102% for vitamin B1, 0.03 µg/ml and 96% for B2, 0.08 µg/ml and 106% for B6, 0.10 µg/ml and 105% for nicotinamide and 0.03 µg/ml and 81% for nicotinic acid, respectively. Repeated.injections showed a relative standard deviation lower than 5% for vitamin B1, B2 and nicotinamide, 10% for vitamin B6 and 13% for nicotinic acid, respectively. In some of the products analized the vitamin levels agreed with those printed on the package. Although some slight quantitative variations were found within biscuits, one sample had levels of ribot1avin 35% lower than the value stated on the package. Of five different com cereal brands, only one had the declared vitamin content, the others were 30% lower. No B-group vitamins were detected in one brand of enriched macaroni, except for the nicotinic acid naturally present in the t1om. On the other hand, one t1avored milk drink exhibited vitamins levels 200% higher than the amounts stated on the label and one milk drink mix had thiamin, ribot1avin and nicotinamide levels 3 to 5 times greater than stated. These results suggest an absence of control of the amount of vitamins in enriched foods.
Doutorado
Doutor em Ciência de Alimentos

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DEVINAT, JEAN-CHRISTOPHE. "A propos d'un cas d'insuffisance cardiaque par hypovitaminose b1 chez un alcoolique." Aix-Marseille 2, 1994. http://www.theses.fr/1994AIX20152.

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Granier, Patrick. "Etude comparative des taux plasmatiques et sanguins de thiamine après adminisatration orale chez le sujet âgé." Montpellier 1, 1995. http://www.theses.fr/1995MON11173.

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19

Vachaud, Cécile. "Les modifications mécanocardiographiques induites par la vitamine B1 : valeur, signification diagnostique, orientation thérapeutique." Montpellier 1, 1990. http://www.theses.fr/1990MON11220.

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Souza, Bianca Rodrigues de. "Quantificação das vitaminas do complexo B (B1, B2) e vitâmeros das vitaminas B3 e B6 em amostras de pólen apícola desidratado provenientes da Região Sul do Brasil." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/9/9131/tde-27052015-141055/.

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Entende-se por pólen apícola o resultado da aglutinação do pólen das flores, efetuado pelas abelhas operárias, mediante néctar e substâncias salivares, o qual é recolhido no ingresso da colmeia. A literatura descreve que esse alimento contém proteínas, carboidratos, lipídeos, vitaminas e minerais. De acordo com estudo prévio, amostras de pólen apícola in natura e desidratado, da cidade de Pariquera-Açu (São Paulo), apresentaram teores significativos de vitamina B1(tiamina) e B2 (riboflavina), além da presença dos vitâmeros da vitamina B3 (ácido nicotínico e nicotinamida) e B6 (piridoxal, piridoxol e piridoxamina) em sua composição o que foi associado à flora local explorada pelas abelhas. A região Sul do Brasil possui clima, relevo e vegetação diferenciados de outras regiões, necessitando-se assim da verificação do potencial vitamínico deste produto local. Destaca-se, ainda, o fato de que nesta região encontra-se um dos dois maiores produtores nacionais de pólen apícola (estado de Santa Catarina). O presente trabalho teve como objetivo principal quantificar os teores das vitaminas do complexo B: vitaminas B1 e B2, assim como os vitâmeros das vitaminas B3 e B6. Foram coletados 28 lotes de pólen apícola desidratado de diferentes localidades da região Sul durante o período de agosto de 2011 a dezembro de 2012 que posteriormente foram armazenados, a -18 °C até o momento das análises. As vitaminas do complexo B foram analisadas por cromatografia liquida de alta eficiência (CLAE) na matriz pólen apícola desidratado e os resultados foram expressos em base seca. Entre as amostras analisadas foram verificados teores de vitamina B1 variando entre 0,46 e 1,83 mg / 100 g de pólen apícola; vitamina B2 de 0,40 à 1,86 mg / 100 g e quanto à vitamina B6 apenas os vitâmeros piridoxal e piridoxamina puderam ser quantificados em todos os lotes analisados. O piridoxal teve variação entre as amostras de 0,42 à 6,70 mg / 100 g e a piridoxamina de 0,26 à 0,95 mg / 100g. Em relação à vitamina B3, o vitâmero ácido nicotínico apresentou-se nos diferentes lotes variando de 0,68 à 3,93 mg / 100 g e a nicotinamida de 0,27 à 5,54 mg / 100 g de produto. Tomando-se como porção sugerida para consumo diário 25 g de pólen apícola, verificou-se que num total de 28 amostras, 15 foram consideradas fontes e 2 como ricas em tiamina; 19 lotes foram fontes e 3 ricos em riboflavina, e; 2 lotes foram fontes e 26 ricos em piridoxina segundo à Ingestão Diária Recomendada (IDR) para adultos como disponibilizado na Resolução de Diretoria Colegiada (RDC) nº. 269, de 22 de setembro de 2005.
Bee pollen is understood to be the result of agglutination of pollen from flowers, made by worker bees, and nectar through salivary substances, which is collected at the hive entrance. The literature describes that this product contains proteins, carbohydrates, lipids, vitamins, minerals. Previous study with fresh and dehydrated bee pollen, from the city of Pariquera-Açu (São Paulo) showed significant levels of vitamin B1 (thiamine), B2 (riboflavin), presence of B3 (nicotinic acid and nicotinamide) and B6 (pyridoxal, pyridoxamine, piridoxol) vitamins vitamers in its composition which was associated with the local flora explored by bees. Southern Brazil has a differentiated climate, topography and vegetation from other regions, thus requiring verification of vitamin potential of this local product. Also stands out the fact that this region is one of the two largest national producers of bee pollen (Santa Catarina state). This study aimed to quantify the levels of B complex vitamins: vitamins B1, B2, as well as the vitamers of vitamins B3 and B6. Thus, it was collected 28 batches of dehydrated bee pollen from different locations in the South during the period from August 2011 to December 2012. Samples were obtained and subsequently stored at -18 ° C until the analysis time. B vitamins were analyzed by high performance liquid chromatography (HPLC) in bee pollen dehydrated matrix and results were expressed on a dry basis. Among the samples it levels of vitamin B1 varied from 0.46 to 1.83 mg / 100 g; vitamin B2 from 0.40 to 1.86 mg / 100 g; and for vitamin B6, only the pyridoxal and pyridoxamine vitamers could be quantified in all analyzed batches. The pyridoxal had variation between samples from 0.42 to 6,70 mg / 100 g and pyridoxamine from 0.26 to 0.95 mg / 100g. Taking 25 g of bee pollen as suggested for daily intake portion, it was found in a total of 28 samples that 15 were considered sources and 2 rich in thiamine; 19 lots were sources and 3 rich in riboflavin, and; 2 lots were sources and 26 rich in pyridoxine in relation to the Reference Daily Intake (RDI) for adults as provided in Resolução de Diretoria Colegiada (RDC) nº 269, de setembro de 2005.

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Hamonet, Magali. "Etude comparative des taux plasmatiques de thiamine après administration parentérale et orale chez le sujet âgé dénutri." Montpellier 1, 1990. http://www.theses.fr/1990MON11202.

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Coz, Martel Karin Elman, and Ramos Sara Regina Huamán. "Validación de un método analítico para la determinación de vitamina B1 en leche UHT enriquecida y endulzada por cromatografía líquida de alta eficiencia H.P.L.C." Universidad Nacional Mayor de San Marcos. Programa Cybertesis PERÚ, 2007. http://www.cybertesis.edu.pe/sisbib/2007/huaman_rs/html/index-frames.html.

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Se presentan los resultados obtenidos en la validación de un método analítico por cromatografía líquida de alta resolución, para la determinación de vitamina B1, en leche UHT Enriquecida y Endulzada, el cual se diseñó para separar la tiamina, con la utilización de una columna RP-18 de 150 x 4.6 mm y un detector UV-Visible. Dicho método se empleó para el control de la calidad de este producto. El método fue validado siguiendo una metodología de trabajo elaborado previamente en un protocolo de validación, donde se analizaron diferentes parámetros como son: selectividad, linealidad, presición, exactitud. Se procede a recopilar toda la información bibliográfica necesaria para luego realizar los primeros análisis exploratorios definiendo las condiciones cromatográficas finales. Definida las condiciones se inicia los análisis para la evaluación de los parámetros de validación y se demuestra mediante el diseño experimental y los procedimientos estadísticos empleados que la técnica analítica propuesta es lineal por que se obtiene un coeficiente de determinación de r2= 0.9998; es exacta por que se obtiene un porcentaje de recuperación de 100.07%; es precisa ya que para la repetibilidad se obtiene un RSD de 0.446% y para la precisión intermedia se demuestra que no existe diferencias entre las varianzas de los analistas; finalmente es selectiva por que no se evidencian picos interferentes cumpliendo así con los parámetros de validación establecidas en las obras oficiales, por lo cual, el método validado es confiable y puede ser empleado en el análisis de rutina
The results obtained in the validation of an analytic method by chromatography liquid of high resolution are presented, for the decision of vitamin B1, in milk UHT enriched and sweetened, which was designed to separate the thiamine, with the utilization of a column RP-18 of 150 x 4.6 mm and a detector UV- Visible. Said method was employed for the control of the quality of this product. The validation of an analytic method includes the evaluation of a series of parameters. They are: selectivity, linearity, precision, accuracy. We compilated all the bibliographic information we need to do the first exploratory analyses which define the final chromatographic conditions. Then, when the conditions were defined, we started the analyses for the evaluation of validation’s parameters. It was shown by the experimental design and the statistic procedures, that the proposed analytical technique is linear because the correlation coefficient obtained was r2= 0.9998; it is accurate, it was obtained a recuperation percentage of 100.07%; is precise since for the repeatability obtained was RSD of 0.446% and for the intermediate precision it is shown that do not exist differences among the variances of the analysts, finally is selective because there is no evidence of interferential chromatographic peaks. The proposed technique accomplished all established validation’s parameters established in the official papers. Thus, the validate method is reliable and it can be used in the routine analyses

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LANDA, TRUJILLO JOSÉ ÁNGEL. "Efecto de la administración de vitamina B1 sobre el comportamiento productivo de toretes en corral de engorda." Tesis de Licenciatura, Universidad Autónoma del Estado de México, 2016. http://hdl.handle.net/20.500.11799/66339.

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El objetivo del presente estudio fue evaluar el efecto de la adición a la dieta de vitamina B1 sobre el comportamiento productivo de bovinos en corral de engorda. Se emplearon 20 toretes F1 (Cebú/Suizo) con un peso promedio de 319.95 ± 5.02 kg. los cuales se dividieron al azar en dos grupos de 10 animales cada uno. Al inicio del experimento los toretes fueron pesados, bacterinizados contra clostridiasis y pasterelosis neumónica, y desparasitados con ivermectina a una dosis de 200 μg/ Kg. de peso vivo (PV) por vía subcutánea, además se les aplico vitamina ADE por vía intramuscular a una dosis de 250000 u.i/animal al inicio del experimento y posteriormente se pesaron hasta finalizar el experimento. Los toretes fueron alojados en dos corrales diferentes los cuales contaron con suministro de agua y alimento ad libitum, la asignación del alimento fue manual pesando diariamente la cantidad a suministrar hasta finalizar el experimento el cual tuvo una duración de 90 días. El grupo 1 (experimental) recibió una dieta con la adición de vitamina B1, el grupo 2 permaneció como el grupo control, el cual recibió la misma dieta sin la adición de vitamina B1. Los resultados del presente experimento fueron sometidos a un análisis de varianza a través de un diseño completamente al azar. El peso promedio de los toros al inicio del experimento, fue de 316.14 ± 53 kg. y de 323.50 ± 49.10 kg. para los tratamientos 1 y control respectivamente. En relación al peso promedio final de los toros, estos fueron de: 446.2 ± 64.80 kg. y 434.60 ± 51.13 kg., el promedio de ganancia total por toro fue de 129.8 ± 33.00 kg. y 111.10 ± 15.73 kg., así como la ganancia diaria de peso por toro la cual fue de: 1.44 ± 0.37 kg. y 1.23 ± 0.17 kg. para los tratamientos 1 y control respectivamente, no observándose diferencias estadísticamente significativas para ninguna de estas variables (P>0.05). El consumo total de alimento para el tratamiento 1 fue de 10300 kg. y de 10150 kg. para el grupo control. El consumo total de alimento por toro fue de 1030 kg. y de 1050 kg. para los toros del tratamiento 1 y grupo control respectivamente. El consumo de alimento por toro al día fue muy similar para los dos grupos siendo de 11.44 kg. para el tratamiento 1 y de 11.28 kg. para el grupo control. La conversión alimenticia fue de 7.94 kg. y de 9.14 kg. para el tratamiento 1 y el grupo control respectivamente. La eficiencia alimenticia fue de 12.60% y 10.95 % para los grupos 1 y control respectivamente. Se concluye que bajo las condiciones en las que se realizó el presente estudio la suplementación en la dieta con vitamina B1 en toretes de engorda constituye una herramienta innovadora para mejorar la eficiencia y el desempeño de los animales, aumentando la ganancia de peso y la eficiencia alimenticia, lo que incrementará la rentabilidad de los corrales de engorda de bovinos.

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Huamán, Ramos Sara Regina, and Martel Karin Elman Coz. "Validación de un método analítico para la determinación de vitamina B1 en leche UHT enriquecida y endulzada por cromatografía líquida de alta eficiencia H.P.L.C." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2007. https://hdl.handle.net/20.500.12672/1085.

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Se presentan los resultados obtenidos en la validación de un método analítico por cromatografía líquida de alta resolución, para la determinación de vitamina B1, en leche UHT Enriquecida y Endulzada, el cual se diseñó para separar la tiamina, con la utilización de una columna RP-18 de 150 x 4.6 mm y un detector UV-Visible. Dicho método se empleó para el control de la calidad de este producto. El método fue validado siguiendo una metodología de trabajo elaborado previamente en un protocolo de validación, donde se analizaron diferentes parámetros como son: selectividad, linealidad, presición, exactitud. Se procede a recopilar toda la información bibliográfica necesaria para luego realizar los primeros análisis exploratorios definiendo las condiciones cromatográficas finales. Definida las condiciones se inicia los análisis para la evaluación de los parámetros de validación y se demuestra mediante el diseño experimental y los procedimientos estadísticos empleados que la técnica analítica propuesta es lineal por que se obtiene un coeficiente de determinación de r2= 0.9998; es exacta por que se obtiene un porcentaje de recuperación de 100.07%; es precisa ya que para la repetibilidad se obtiene un RSD de 0.446% y para la precisión intermedia se demuestra que no existe diferencias entre las varianzas de los analistas; finalmente es selectiva por que no se evidencian picos interferentes cumpliendo así con los parámetros de validación establecidas en las obras oficiales, por lo cual, el método validado es confiable y puede ser empleado en el análisis de rutina.
The results obtained in the validation of an analytic method by chromatography liquid of high resolution are presented, for the decision of vitamin B1, in milk UHT enriched and sweetened, which was designed to separate the thiamine, with the utilization of a column RP-18 of 150 x 4.6 mm and a detector UV- Visible. Said method was employed for the control of the quality of this product. The validation of an analytic method includes the evaluation of a series of parameters. They are: selectivity, linearity, precision, accuracy. We compilated all the bibliographic information we need to do the first exploratory analyses which define the final chromatographic conditions. Then, when the conditions were defined, we started the analyses for the evaluation of validation’s parameters. It was shown by the experimental design and the statistic procedures, that the proposed analytical technique is linear because the correlation coefficient obtained was r2= 0.9998; it is accurate, it was obtained a recuperation percentage of 100.07%; is precise since for the repeatability obtained was RSD of 0.446% and for the intermediate precision it is shown that do not exist differences among the variances of the analysts, finally is selective because there is no evidence of interferential chromatographic peaks. The proposed technique accomplished all established validation’s parameters established in the official papers. Thus, the validate method is reliable and it can be used in the routine analyses.
Tesis

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Sánchez, Huamaní Juan Pablo. "Eficacia analgésica de diclofenaco más vitaminas b1, b6 y b12 en comparación a sólo diclofenaco en cirugía de tercera molar inferior." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2015. https://hdl.handle.net/20.500.12672/4541.

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Esta tesis está basada en un ensayo clínico, simple-ciego y no aleatorizado, realizado en el servicio de Cirugía Oral y Maxilofacial del Hospital Nacional Hipólito Unanue, cuyo objetivo fue determinar si la terapia con diclofenaco más vitaminas B es superior a la terapia con sólo diclofenaco en pacientes sometidos a cirugía electiva de tercera molar inferior. Se formaron 2 grupos, un grupo recibió diclofenaco más vitaminas B y el otro diclofenaco solo. La variable principal fue la intensidad de dolor medida luego de 1, 3, 6, 9, 12 y 24 horas de finalizada la cirugía mediante una escala gráfica verbal del 0-100; las variables secundarias fueron el tiempo para analgesia de rescate y la cantidad de analgésicos consumidos en el postoperatorio. Treinta pacientes completaron el estudio, quince de ellos recibieron diclofenaco (75 mg) más una mezcla de vitaminas B (B1: 100 mg, B6: 100 mg y B12: 10 mg) y los otros quince solamente diclofenaco (75 mg). Ambas terapias fueron administradas por vía intramuscular al finalizar la cirugía. Los resultados mostraron que la adición de vitaminas B al diclofenaco mejoró la eficacia analgésica del diclofenaco en la variable principal pero no de manera estadísticamente significativa (p > 0.05). Palabras clave: diclofenaco - vitaminas b - cirugía dental - tercera molar impactada
--- This thesis is based on a single-blind, non-randomized clinical trial which took place in the oral and maxillofacial surgery service of the Hipólito Unanue National Hospital, of which objective was to determine if the therapy using diclofenac plus B vitamins is better than the therapy using only diclofenac in patients subjected to elective surgery of inferior third molar. Two groups were formed, a group received diclofenac plus B vitamins and the other group received diclofenac only. The main variable was the intensity of pain measured after 1, 3, 6, 9, 12 and 24 hours the surgery had finished using a verbal graphic scale (0-100); the secondary variables were the time for rescue analgesics consumption and the amount of rescue analgesics taken in the postoperative period. Thirty patients completed the study, fifteen of them received diclofenac (75 mg) plus B vitamins (B1: 100 mg, B6: 100 mg and B12: 10 mg) and other fifteen patients received only diclofenac (75 mg). Both therapies were administered by intramuscular route once the surgery was finished. The results showed that by adding B vitamins to diclofenac improved the analgesic effectiveness of diclofenac in the main variable but there were no statistically significant differences. Keywords: diclofenac – b vitamins – dental surgery – impacted third molar
Tesis

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Soayfane, Zeina. "Implication des transporteurs SR-B1, NPC1L1 et la P-glycoprotéine dans l'absorption intestinale des composés lipophiles." Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1399/.

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L'absorption intestinale des lipides et des micronutriments à caractère lipophile fait intervenir des transporteurs de la membrane apicale de l'entérocyte tels que NPC1L1, SR-B1 et CD36. Pour les xénobiotiques incluant les médicaments lipophiles, les transporteurs ABC multidrogues, comme la P-glycoprotéine (Pgp) ou MRP ou BCRP, interviennent en effluant et en limitant la biodisponibilité de ces composés dans l'organisme. Ils sont aussi capables de transporter des lipides comme le cholestérol et les phospholipides. De plus, un rôle dans l'homéostasie des lipides a été évoqué pour la Pgp. Les objectifs de cette thèse ont été (i) de caractériser la contribution de NPC1L1 et SR-B1 dans l'absorption du cholestérol et d'une vitamine liposoluble, la vitamine E ou tocophérol, tout au long de l'intestin grêle, (ii) d'identifier le rôle de la Pgp dans l'homéostasie des lipides dans l'organisme et enfin (iii) d'évaluer le rôle de la Pgp dans la biodisponibilité de l'ivermectine, un médicament anthelmintique lipophile, lorsqu'elle est administrée dans des formulations lipidiques. Nous avons montré que les cellules Caco-2 sont capables d'absorber le cholestérol et le tocophérol incorporés dans des micelles contenant de l'acide oléique, selon une voie commune, faisant intervenir NPC1L1 et SR-B1. Chez la souris, nous avons montré que le tocophérol est majoritairement absorbé au niveau du jéjunum médial et distal. Nous avons également mis en évidence un rôle spécifique de ces transporteurs en fonction de leur localisation intestinale : NPC1L1 intervient tout au long de l'intestin dans l'absorption du cholestérol et seulement au niveau distal pour le tocophérol. SR-B1 intervient dans l'absorption du cholestérol au niveau distal et dans celle du tocophérol au niveau proximal de l'intestin (Publication 1: Soayfane et al. , 2011). Par ailleurs, nous avons mis en évidence un rôle important de la P-glycoprotéine (Pgp) dans le maintien de l'homéostasie des lipides. Les souris déficientes en Pgp développent une obésité associée à des troubles métaboliques (stéatose hépatique, hyperinsulinémie) (Publication 2: Foucaud-Vignault et al. , 2011) mais ont aussi une triglycéridémie postprandiale augmentée par rapport aux souris sauvages. Parmi les mécanismes explorés, nous avons montré que les souris déficientes en Pgp avaient une diminution de l'absorption intestinale des lipides et une captation plus importante des lipides par le tissu adipeux (Publication 3: Soayfane et al. , en préparation). Enfin, la biodisponibilité de l'ivermectine formulée dans de l'huile ou avec un émulsifiant, le polysorbate 80, a été évaluée. Nous avons montré chez la souris que le polysorbate augmente de façon marquée la biodisponibilité de l'ivermectine via l'inhibition de la Pgp (Publication 4: Soayfane et al. , en préparation). En conclusion, nous avons contribué à élucider certains mécanismes qui sous-tendent l'absorption intestinale de différents composés lipidiques. Différents rôles de NPC1L1 et SR-B1 dans l'absorption du cholestérol et du tocophérol ont été établis tout au long de l'intestin. De plus, d'autres transporteurs semblent intervenir dans l'absorption du tocophérol au niveau médial et distal de l'intestin. D'autre part, l'homéostasie des lipides est profondément affectée chez la souris déficiente en Pgp révélant une nouvelle fonction physiologique possible pour la Pgp en relation avec le développement de l'obésité. Enfin, des formulations à base de composés capables d'inhiber la Pgp augmentent la biodisponibilité des médicaments lipophiles dans l'organisme et pourraient contribuer ainsi à améliorer l'efficacité. Ces travaux devraient contribuer à potentialiser l'absorption de composés lipophiles clé de notre alimentation comme les vitamines liposolubles mais aussi certains médicaments lipophiles
Intestinal absorption of lipids and lipophilic micronutrients involves apical membrane transporters of the enterocyte such as NPC1L1, SR-B1 and CD36. In addition, multidrug ABC transporters such as P-glycoprotein (Pgp) or MRP or BCRP, are involved in effluxing and in limiting the bioavailability of lipophilic xenobiotics including drugs in the body. They can also transport lipids such as cholesterol or phospholipids, suggesting a role of these transporters in the lipid turn-over. The objectives of the thesis were (i) to characterize the contribution of NPC1L1 and SRB1 in the cholesterol and vitamin E (tocopherol) absorption throughout the small intestine, (ii) to identify the role of Pgp in the lipid homeostasis in the body and (iii) to evaluate the influence of lipid formulations on the Pgp-mediated transport of ivermectin, a lipophilic drug from anthelmintic macrocyclic lactone family. In Caco-2 cells, in the presence of oleic acid, the cholesterol and tocopherol share common uptake pathways through NPC1L1 and SR-B1. In mice, we showed that the absorption of tocopherol occurred in the medial and distal jejunum. Specific roles in the absorption of cholesterol and tocopherol were envisaged for these transporters based on their intestinal localization. NPC1L1-mediated intestinal absorption of cholesterol occurs throughout the small intestine while it takes place in the distal part for tocopherol. SR-B1 is involved in the in distal intestinal absorption of cholesterol and in the proximal intestine for tocopherol (Publication 1: Soayfane et al. , 2011). In addition, Pgp-deficient mice developed metabolic disorders and obesity suggesting an important role of this transporter in the maintenance of lipid homeostasis (Publication 2: Foucaud- Vignault et al. , 2011). Moreover, a significant decrease in postprandial triglyceride levels was observed in these mice. Indeed, we have shown that Pgp deficiency is associated with a decrease in intestinal fat absorption and increased uptake of lipids by adipose tissue (Publication 3: Soayfane et al. , in preparation). Finally, the bioavailability of ivermectin, formulated in oil or in excipient such as polysorbate 80, was determined. We showed that a polysorbate based-formulation enhanced the bioavailability of ivermectin in mice by inhibiting the Pgp (Publication 4: Soayfane et al. , in preparation). In conclusion, we have contributed to the understanding of some mechanisms underlying the intestinal absorption of several lipophilic compounds. Specific roles of NPC1L1 and SR-B1 were determined along the intestine in the absorption of cholesterol and tocopherol. In addition, other transporters may be involved in tocopherol absorption in the medial and distal intestine. Moreover, lipid homeostasis is disturbed in the absence of Pgp. An obesity and a decrease in the postprandial triglyceridemia occurred in Pgp-deficient mice. These results could reveal new physiological functions of Pgp. Finally, vehicule-based formulations which are able to inhibit Pgp, should improve the bioavailability and certainly the efficacy of lipophilic drugs. This work should contribute to better understand the mechanisms underlying lipid absorption and will allow to propose strategy to enhance the absorption of key lipophilic compounds such as those contained in our diet or therapeutical agents

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Ramos, Karla Lisboa. "Desenvolvimento, validação e determinação simultanea das vitaminas Tiamina (B1) e Riboflavina (B2) em vegetais folhosos não convencionais, por CLAE." [s.n.], 2002. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254315.

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Orientadores: Helena Teixeira Godoy, Elizabeth Maria Tala de Souza
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo; No Brasil, programas de alimentação alternativa estimulam o consumo de novas fontes alimentares. Instituições não governamentais adotaram o uso de não convencionais, ou alimentos alternativos, com a finalidade de prevenir e recuperar crianças desnutridas com idade pré-escolar. Entretanto, a falta de metodologias analíticas apropriadas dificulta o conhecimento dos teores de micronutrientes, em especial as vitaminas, em alimentos não convencionais. Com a finalidade de suprir essa carência, este trabalho desenvolveu e validou uma metodologia para determinação simultânea das vitaminas 81e 82 por CLAE. O método desenvolvido foi aplicado a folhosos verde-escuros não convencionais, como beldroega (Portulacca oleracea L.), caruru (Amaranthus sp), serralha (Sonchus oleraceus L.), tanchagem (Plantago tomentosa Lom.) e pó da folha de mandioca (Manihot esculenta). ... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital.
Abstract: In Brazil, programs of alternative feeding stimulate the consumption of new food sources. Non governmental institutions adopted the use of unconventional foods or alternative foods with the purpose of preventing and recovering malnourished children in preschool age. However, the lack of appropriate analytical methodologies turns difficult the assessment of micronutrients levels, specially vitamins, in unconventional foods. In order to fil! this deficiency, this work developed and validated a methodology for simultaneous determination of vitamins 81 and 82, by HPLC. The developed method was applied to unconventional dark green leaf vegetables, as beldroega (Oleracea Portulacca L.), caruru (Amaranthus sp), serralha (Sonchus oleraceus L), tanchagem (Tomentosa Plantago Lom.) and cassava leaf powder (Manihot esculenta). Vitamins 81 and 82 were extracted with HCI 0.1N followed by enzymatic hydrolysis. ... Note: The complete abstract is available with the full electronic digital thesis or dissertations.
Mestrado
Mestre em Ciência de Alimentos

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Jannusch, Kai [Verfasser], and Svenja [Gutachter] Caspers. "Das komplexe Zusammenspiel der Vitamine B6 und B1 mit kognitiver Funktion, Hirnstruktur und funktioneller Konnektivität in der älteren Bevölkerung / Kai Jannusch ; Gutachter: Svenja Caspers." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2019. http://d-nb.info/1201881943/34.

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Oliveira, Gersilene Valente de. "Vitaminas B1, B6, B12 e Complexo B na prevenÃÃo da discinesia orofacial induzida por haloperidol em ratos: avaliaÃÃo comportamental e mecanismos associados." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16133.

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CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior
A Discinesia tardia (DT) Ã caracterizada por movimentos involuntÃrios, principalmente na parte inferior da face, prÃximos da boca, com espasmos que podem ser leves ou severos. Ã uma alteraÃÃo motora grave relacionada, mas nÃo restrita Ã terapia antipsicÃtica. Tratamentos com antipsicÃticos principalmente os da classe dos tÃpicos, como o haloperidol (HAL) aumentam os riscos de DT. A fisiopatologia da DT Ã associada a um desequilÃbrio em sistemas de neurotransmissÃo, dentre eles dopaminÃrgico e colinÃrgico, bem como com desequilÃbrio oxidativo, principalmente em Ãreas cerebrais relacionadas ao controle do movimento, como o corpo estriado. As vitaminas (vit.) B, por sua vez, apresentam efeitos antioxidantes sendo cofatores para enzimas relacionadas Ã sÃntese de neurotransmissores. Neste contexto, o presente trabalho teve como objetivo determinar os efeitos preventivos das vit. B1, B6, B12 ou Complexo B na discinesia orofacial (DO) induzida por HAL em ratos. Foram utilizados ratos Wistar machos tratados por via intraperitoneal com HAL (1 mg/kg, i.p.) por 21 dias ou concomitantemente com HAL e as vit. B1 (60 mg/kg), B6 (60 mg/kg) ou B12 (0,6 mg/kg) por via subcutÃnea, sozinhas ou em associaÃÃo (complexo B). O complexo B consistiu na mistura das 3 vitaminas em iguais proporÃÃes. Um grupo de animais foi administrado clozapina (25 mg/kg), um antipsicÃtico atÃpico nÃo relacionado ao desenvolvimento de DO. Os testes comportamentais foram realizados apÃs 30 minutos no 1Â, 7Â e 21Â dias de administraÃÃo das fÃrmacos e consistiram na determinaÃÃo da atividade locomotora, catalepsia e movimentos de mastigaÃÃo no vazio. No 21Â dia os animais foram sacrificados e retiradas Ãreas cerebrais para as anÃlises neuroquÃmicas e de expressÃo para tirosina hidroxilase (TH), receptores dopaminÃrgicos D1 e D2 e receptor muscarÃnico M1. Os resultados mostraram que o HAL aumentou o tempo de catalepsia no dia 7 e causou DO no dia 21. A administraÃÃo das vit. B (B1: B6: B12) sozinhas ou em associaÃÃo, juntamente com HAL, preveniu o desenvolvimento de DO e em menor extensÃo da catalepsia. O efeito preventivo das vit. B foi acompanhado por restauraÃÃo dos nÃveis de glutationa reduzida (GSH) e peroxidaÃÃo lipÃdica. AlÃm dos efeitos antioxidantes, as vit. B aumentaram a atividade da enzima acetilcolinesterase (AChE) em todas as Ãreas cerebrais estudadas, com o incremento mÃximo de atividade observada no hipocampo de animais co-tratados com vit. B12 e coquetel de vit. B. A clozapina nÃo induziu DO e aumentou a atividade AChE semelhante para os grupos co-administrados com vit. B e HAL. A anÃlise da expressÃo de receptores e enzimas relacionadas Ã sÃntese de neurotransmissores no corpo estriado por PCR-RT revelou que o HAL foi capaz de aumentar a expressÃo de receptores dopaminÃrgicos D1 e D2 e reduzir a expressÃo dos receptores muscarÃnicos M1. A expressÃo da tirosina hidroxilase (TH), passo limitante para a sÃntese de dopamina, se apresentou reduzida pelo HAL. Os dados sugerem que as vitamina do complexo B sÃo capazes de prevenir as alteraÃÃes induzidas pelo HAL apresentando, portanto, um papel promissor na prevenÃÃo de DO associada ao uso desta fÃrmaco.
Tardive dyskinesia (TD) is characterized by involuntary movements, mostly at lower face, near the mouth, with convulsion that can be light or hard. Is one severe disorder related, but restricted the antipsychotic therapy. Antipsychotic treatments above all the class of typical, like haloperidol (HAL) increase the risk of TD. The pathophysiology of TD is associated to a instability in neurotransmission system, such as dopaminergic and cholinergic, among others, as well as with oxidative instability mainly in brain areas related to the control of movement, as the striatum. B vitamins, in turn, show antioxidants effect and are cofactors to enzymes related to the synthesis of neurotransmitters. In this context, the present study aimed to determine the preventive effects of B1, B6, B12 vitamins or B complex against orofacial dyskinesia (OD) induced by HAL in rats. To do this male Wistar rats were intraperitoneally administered HAL (1 mg/kg, i.p.) for 21 days or concomitantly received HAL, B1 (60 mg/kg), B6 (60 mg/kg) or B12 (0,6 mg/kg) vitamin subcutaneously alone or in association. B complex consisted in the mix of 3 vitamins in equal proportions. One group of animals was administered with clozapine (25 mg/kg), an atypical antipsychotic not related to the development of OD. Behavioral tests were performed at the 1st, 7th and 21st days of drugs administration. The behavioral tests performed were locomotor activity, catalepsy and chewing vacuous movements. At 21st day the animals were sacrificed and had their brain areas dissected for neurochemical analysis. The results showed that HAL increased catalepsy time at 7th day and OD at 21st day. Administration of B vitamins (B1:B6:B12) alone or in association, together with HAL, prevented the development of OD and in a lower extension, catalepsy. Preventive effect of B vitamins was accompanied by restoration of the levels of reduced glutathione (GSH) and lipid peroxidation. Beyond the antioxidant effects, B vitamins increased the activity of the enzyme acetylcholinesterase (AChE) in all brain areas studied, with the maximum increase of activity observed in the hippocampus of animals co-administered with B12 vitamins and B vitamins cocktail. Clozapine did not induce OD and increase in the activity of AChE. Analysis of the expression of receptors and enzymes related to the synthesis of neurotransmitters in striatum by PCR-RT revealed that HAL increased the expression of the dopaminergic receptors D1 and D2 and reduce an expression of the muscarinic receptors M1. Haloperidol decreased the expression of tyrosine hydroxylase (TH), a limiting step for the synthesis of dopamine. Taken together the results suggest that B vitamins prevented changes induced by HAL, presenting thus a promising role as a preventive approach against HAL-induced OD.

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Tang, Jing Jing. "Intérêt du profil chromatographique des acides organiques urinaires pour le diagnostic de carences en vitamines du groupe B (B1, B2, B8, B12)." Nutrition humaine, 1993. http://www.theses.fr/1993NAN10258.

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31

Oliveira, Gersilene Valente de. "Vitaminas B1, B6, B12 e Complexo B na prevenção da discinesia orofacial induzida por haloperidol em ratos : avaliação comportamental e mecanismos associados." reponame:Repositório Institucional da UFC, 2015. http://www.repositorio.ufc.br/handle/riufc/15726.

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OLIVEIRA, Gersilene Valente de. Vitaminas B1, B6, B12 e Complexo B na prevenção da discinesia orofacial induzida por haloperidol em ratos: avaliação comportamental e mecanismos associados. 2015. 120 f. Tese (Doutorado em Farmacologia) – Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, 2015.
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Tardive dyskinesia (TD) is characterized by involuntary movements, mostly at lower face, near the mouth, with convulsion that can be light or hard. Is one severe disorder related, but restricted the antipsychotic therapy. Antipsychotic treatments above all the class of typical, like haloperidol (HAL) increase the risk of TD. The pathophysiology of TD is associated to a instability in neurotransmission system, such as dopaminergic and cholinergic, among others, as well as with oxidative instability mainly in brain areas related to the control of movement, as the striatum. B vitamins, in turn, show antioxidants effect and are cofactors to enzymes related to the synthesis of neurotransmitters. In this context, the present study aimed to determine the preventive effects of B1, B6, B12 vitamins or B complex against orofacial dyskinesia (OD) induced by HAL in rats. To do this male Wistar rats were intraperitoneally administered HAL (1 mg/kg, i.p.) for 21 days or concomitantly received HAL, B1 (60 mg/kg), B6 (60 mg/kg) or B12 (0,6 mg/kg) vitamin subcutaneously alone or in association. B complex consisted in the mix of 3 vitamins in equal proportions. One group of animals was administered with clozapine (25 mg/kg), an atypical antipsychotic not related to the development of OD. Behavioral tests were performed at the 1st, 7th and 21st days of drugs administration. The behavioral tests performed were locomotor activity, catalepsy and chewing vacuous movements. At 21st day the animals were sacrificed and had their brain areas dissected for neurochemical analysis. The results showed that HAL increased catalepsy time at 7th day and OD at 21st day. Administration of B vitamins (B1:B6:B12) alone or in association, together with HAL, prevented the development of OD and in a lower extension, catalepsy. Preventive effect of B vitamins was accompanied by restoration of the levels of reduced glutathione (GSH) and lipid peroxidation. Beyond the antioxidant effects, B vitamins increased the activity of the enzyme acetylcholinesterase (AChE) in all brain areas studied, with the maximum increase of activity observed in the hippocampus of animals co-administered with B12 vitamins and B vitamins cocktail. Clozapine did not induce OD and increase in the activity of AChE. Analysis of the expression of receptors and enzymes related to the synthesis of neurotransmitters in striatum by PCR-RT revealed that HAL increased the expression of the dopaminergic receptors D1 and D2 and reduce an expression of the muscarinic receptors M1. Haloperidol decreased the expression of tyrosine hydroxylase (TH), a limiting step for the synthesis of dopamine. Taken together the results suggest that B vitamins prevented changes induced by HAL, presenting thus a promising role as a preventive approach against HAL-induced OD.
A Discinesia tardia (DT) é caracterizada por movimentos involuntários, principalmente na parte inferior da face, próximos da boca, com espasmos que podem ser leves ou severos. É uma alteração motora grave relacionada, mas não restrita à terapia antipsicótica. Tratamentos com antipsicóticos principalmente os da classe dos típicos, como o haloperidol (HAL) aumentam os riscos de DT. A fisiopatologia da DT é associada a um desequilíbrio em sistemas de neurotransmissão, dentre eles dopaminérgico e colinérgico, bem como com desequilíbrio oxidativo, principalmente em áreas cerebrais relacionadas ao controle do movimento, como o corpo estriado. As vitaminas (vit.) B, por sua vez, apresentam efeitos antioxidantes sendo cofatores para enzimas relacionadas à síntese de neurotransmissores. Neste contexto, o presente trabalho teve como objetivo determinar os efeitos preventivos das vit. B1, B6, B12 ou Complexo B na discinesia orofacial (DO) induzida por HAL em ratos. Foram utilizados ratos Wistar machos tratados por via intraperitoneal com HAL (1 mg/kg, i.p.) por 21 dias ou concomitantemente com HAL e as vit. B1 (60 mg/kg), B6 (60 mg/kg) ou B12 (0,6 mg/kg) por via subcutânea, sozinhas ou em associação (complexo B). O complexo B consistiu na mistura das 3 vitaminas em iguais proporções. Um grupo de animais foi administrado clozapina (25 mg/kg), um antipsicótico atípico não relacionado ao desenvolvimento de DO. Os testes comportamentais foram realizados após 30 minutos no 1º, 7º e 21º dias de administração das fármacos e consistiram na determinação da atividade locomotora, catalepsia e movimentos de mastigação no vazio. No 21° dia os animais foram sacrificados e retiradas áreas cerebrais para as análises neuroquímicas e de expressão para tirosina hidroxilase (TH), receptores dopaminérgicos D1 e D2 e receptor muscarínico M1. Os resultados mostraram que o HAL aumentou o tempo de catalepsia no dia 7 e causou DO no dia 21. A administração das vit. B (B1: B6: B12) sozinhas ou em associação, juntamente com HAL, preveniu o desenvolvimento de DO e em menor extensão da catalepsia. O efeito preventivo das vit. B foi acompanhado por restauração dos níveis de glutationa reduzida (GSH) e peroxidação lipídica. Além dos efeitos antioxidantes, as vit. B aumentaram a atividade da enzima acetilcolinesterase (AChE) em todas as áreas cerebrais estudadas, com o incremento máximo de atividade observada no hipocampo de animais co-tratados com vit. B12 e coquetel de vit. B. A clozapina não induziu DO e aumentou a atividade AChE semelhante para os grupos co-administrados com vit. B e HAL. A análise da expressão de receptores e enzimas relacionadas à síntese de neurotransmissores no corpo estriado por PCR-RT revelou que o HAL foi capaz de aumentar a expressão de receptores dopaminérgicos D1 e D2 e reduzir a expressão dos receptores muscarínicos M1. A expressão da tirosina hidroxilase (TH), passo limitante para a síntese de dopamina, se apresentou reduzida pelo HAL. Os dados sugerem que as vitamina do complexo B são capazes de prevenir as alterações induzidas pelo HAL apresentando, portanto, um papel promissor na prevenção de DO associada ao uso desta fármaco.

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Bedie, Kouadio Gerard. "Microencapsulation de composés nutraceutiques dans des complexes protéines-polysaccharides." Doctoral thesis, Université Laval, 2008. http://hdl.handle.net/20.500.11794/19823.

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Ou-Yang, Chia, and 歐陽葭. "Nutrition Status of Vitamin B1､Vitamin B2 in Taiwanese Chinese." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/72355801936776250516.

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Chan, Xie Wah Audrey. "Thiamine utilisation by the malaria parasite Plasmodium falciparum." Phd thesis, 2014. http://hdl.handle.net/1885/155906.

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Thiamine (vitamin B1), is converted into an important cofactor for several enzymes and is an essential nutrient for the human malaria parasite Plasmodium falciparum. The thiamine biosynthesis capacity of the intraerythrocytic stage of P. falciparum is insufficient to meet the parasite's thiamine requirements and, therefore, the parasite needs to scavenge extracellular thiamine in order to support its rapid growth during the erythrocytic stage of its life cycle. Thiamine utilisation by the P. falciparum parasite might therefore serve as a potential antimalarial drug target. The mechanism of thiamine transport and its accumulation in the P. falciparum parasite was investigated in some detail. So too was the antiplasmodial activity of various thiamine analogues. Oxythiamine, a thiamine analogue, inhibited in vitro parasite proliferation via a thiamine-related pathway, as removal of thiamine from the culture medium increased the antiplasmodial activity of oxythiamine. The antiplasmodial mode of action of oxythiamine was investigated by targeted overexpression of key enzymes in thiamine metabolism and utilisation. Overexpression of thiamine pyrophosphokinase (PfTPK; the enzyme which converts thiamine into its active form, thiamine pyrophosphate, TPP) hypersensitised parasites to oxythiamine by up to 1700-fold, consistent with oxythiamine being a substrate for PfTPK and being converted into an antimetabolite. Parasites overexpressing the TPP-dependent enzymes, oxoglutarate dehydrogenase (PfOxoDH) and pyruvate dehydrogenase (PfPDH) are up to 15-fold more resistant to oxythiamine. HPLC analysis of strep-tagged PfOxoDH and PfPDH from pull-down assays of oxythiamine-treated parasites demonstrated the generation of oxythiamine pyrophosphate (OxPP) and its binding to these enzymes in situ. Taken together, the results are consistent with oxythiamine being converted into OxPP within the parasite and with this antimetabolite simultaneously inactivating at least two TPP-dependent enzymes located within distinct organelles. The ability of thiamine analogues, antimalarials and MDR pump inhibitors to inhibit thiamine transport was investigated. Surprisingly, thiamine analogues (including oxythiamine) did not inhibit thiamine transport, but quinine, quinidine and verapamil were effective inhibitors. Moreover, it was found that thiamine accumulation into K1 (chloroquine-resistant) parasites was 3-fold lower than that observed in 3D7 (chloroquine-sensitive) parasites. Due to the difference in thiamine accumulation between K1 and 3D7 parasites, and the inhibitory effect of quinine and verapamil (known inhibitors of PfCRT, the key mediator of chloroquine resistance) on thiamine accumulation, the possibility that PfCRT plays a role in thiamine accumulation by the parasite was investigated. Using previously-generated transgenic parasites with key mutations in PfCRT, data was generated consistent with a role for PfCRT in thiamine accumulation in P. falciparum parasites. Outcomes from this study have advanced our understanding of the utilisation of thiamine by P. falciparum and of the antiplasmodial mechanism of action of thiamine analogues, in particular, oxythiamine. Additionally, it has also resulted in the identification of a number of effective antimalarials in inhibiting thiamine transport by the parasites. The findings described in this thesis, therefore, validate thiamine-utilisation by P. falciparum as a potential target for future antimalarials.

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Deblon, Achim [Verfasser]. "Vitamin B1-Blutspiegel bei Alkoholkrankheiten mit besonderer Berücksichtigung der Alkoholpsychosen / vorgelegt von Achim Deblon." 2007. http://d-nb.info/987465597/34.

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Hsiao-Mei, Lin, and 林筱玫. "Vitamin B1 requirements of juvenile hybrid tilapia (Oreochromis niloticus × O. aureus) and grouper (Epinephelus malabaricus)." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/43247633384430031222.

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碩士
國立海洋大學
食品科學系
90
The study was aimed at quantifying the optimal vitamin B1 (B1) requirements of juvenile hybrid tilapia (Oreochromis niloticus  O. aureus) and grouper (Epinephilus malabaricus). In Experiment I, purified diets with 8 levels (0, 0.5, 1.0, 2.0, 3.0, 4.0, 8.0, 16.0 mg/kg diet) of supplemental vitamin B1 were each fed to triplicate groups of tilapia (mean initial body weight 0.63  0.01 g) for 8 weeks. Results indicated that fish fed the unsupplemented vitamin B1 control diet had lower (P<0.05) weight gain (WG), feed efficiency (FE), protein efficiency ratio (PER) and vitamin B1 concentration in tissues than fish fed diets supplemented with B1. Hepatic and blood transketolase (TK) activity increased, while thiamin pyrophosphate (TPP) effect decreased in fish as the dietary B1 supplementation level increased. Analysis of the WG, blood B1 concentration and TK activity of the fish by broken-line regression indicate that the optimal dietary vitamin B1 requirement for tilapia is approximately 1.4-2.1 mg/kg diet. In Experiment II, purified diets with 8 levels (0, 0.5, 1.0, 2.0, 3.0, 6.0, 10.0, 20.0 mg/kg diet) of supplemental B1 were each fed to triplicate groups of grouper (mean initial body weight 4.09  0.08 g) for 8 weeks. Results indicated that fish fed the B1 unsupplemented control diet had lower WG, FE, PER and tissue vitamin B1 concentration than fish fed diets supplemented with B1. Analysis of the WG, blood B1 concentration and TK activity of the fish by broken-line regression indicate that the optimal dietary vitamin B1 requirement for grouper is approximately 0.7-1.0 mg/kg diet.

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37

Keller, Laura Lee. "Thiamin content of three sources of corn and arepas as determined chemically and microbiologically." 1985. http://hdl.handle.net/2097/27510.

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38

Kim, Chang Soon. "Modification of fluorometric assay for thiamin in chicken muscle." 1986. http://hdl.handle.net/2097/22095.

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39

Yuan-Cheng, Lin, and 林園程. "Studies on 24-hours the vitamin B1 absorption of hybrid tilapia(Oreochromis niloticus × O.aureus) by modified cannulated method." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/29097838716987466579.

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碩士
國立臺灣海洋大學
水產養殖學系
97
The objective of this study was to investigate the vitaminB1 metabolism of hybrid tilapia (Oreochromis niloticus × O.aureus) with a modified cannulated urine collector through the comparisons between two exogenous vitaminB1 supply methods, injection and oral administration, within a 24 -hour duration. There were three replicates each running three fish at a time. Each fish received an exogenous supply of either an injection of 5ml vitamin B1 solution with a certain concentration of 0, 0.1, 0.3, 0.5 and 1ppm, or an oral administration of 0.3%BW vitamin B1 diet at a certain level of 0, 1, 4, 8, 12 and 16ppm in concertration. Blood and urine samples were taken at the 2nd, 4th, 6th, 8th, 10th, 12th, 16th, 20th and 24th hour after the initiation of each run of the experiment. Muscle and liver samples were obtained at the 24th hour in the end of the experiment. It was observed that the plasma concentrations of the whole treatments were all peaked at the 6th hour and urine concentration peaked at the 6th-8th hour after oral administrations of diets. The plasma vitamin B1 peaked at the 2nd hours ,while that for vitamin B1 was at the 4th hour after injection. The delay of 4-6 hours of the plasma vitamin B1 concentration peak and the delay of 2-4 hours of the urine vitamin B1 concentration peak in the oral administration group of fish than the respective two peaks in the injection fish group revealed that vitamin B1 had been absorped in the digestion system 4-6 hours before enough amount of vitamin B1 was transported to circulation system. The amount of vitamin B1 excreted in urine within the 24-hourr experimental duration were 1.60×10-2μg for fish given control diet, 1.22×10-1μg for fish given 1ppm vitamin B1 diet, 2.02×10-1μg given 4ppm diet, 3.20×10-1μg given 8ppm diet, 3.80×10-1μg given 12ppm diet and 4.57μg given 16ppm diet, respectively. While the respective vitamin B1 concentration in urine within the 24-hour experimental duration amounted to a total of 1.62×10-2μg for fish injected control solution, 4.74×10-2μg for fish injected 0.1ppm vitamin B1 solution, 1.15×10-1μg for 0.3ppm solution, 2.43×10-1μg for 0.5ppm solution and 4.85×10-1μg for 1ppm solution. But the amount of vitamin B1 excreted in the urine did not match the amount in proportion in blood which led to a low accumulated percentage excretion for the whole treatments in both injection or oral administration group of fish. By plotting the values of urine vitamin B1 concentration against those of plasma vitamin B1 concentration , it was found that oral administration of 1ppm vitamin B1 diet group of fish and the injection of 0.3 ppm solution group of fish exhibited a higher value of the regression line slope than those of the other treatments compared each in the two respective vitamin B1 supplying methods. So it was concluded that 1ppm diet and 0.3ppm injection of vitamin B1 must be the candidate level for best utilization in hybrid tilapia. Adding an indicator such as innulin in vitamin B1 solutions for a clearance test as well as extending the experimental duration from 24 hours to 48 hours were recommended to assure more detailed information about the vitamin B1 metabolism of this fish be collected.

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40

Asztalos, Peter [Verfasser]. "Untersuchungen zu molekularen, strukturellen und biokatalytischen Aspekten des Vitamin B1-abhängigen Enzyms Transketolase A aus Escherichia coli / von Peter Asztalos." 2008. http://d-nb.info/990783510/34.

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41

Olivard, Sarah. "Studies on Uptake of Thiamin Analogs by a Thiamin Deficient E. coli Mutant Strain." Thesis, 2012. http://hdl.handle.net/1969.1/148374.

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Thiamin transport in Escherichia coli is a model system to establish the tolerance of derivatives for transport into the cell. Since little is known about what types of thiamin derivatives may be successfully taken into the cell through the transport system, a series of thiamin derivatives are synthesized. A thiamin amino analog is synthesized and tested to determine the use of the analog as an alternate source of thiamin for growth of an E. coli thiamin mutant. Formate, acetate, and benzoate thiamin esters are synthesized and tested as alternate sources for growth of an E. coli thiamin mutant. Thiamin esters or amides may provide a scaffold for attaching other small molecules of interest to be imported into the cell by thiamin transport system. Thiamin containing formate, acetate, and benzoate esters were synthesized and tested as alternative growth source for thiamin using an E. coli mutant strain incapable of synthesizing thiamin. All three synthesized ester thiamin forms gave a zone of growth determined by disk-assay study. Also, an amino thiamin is synthesized to determine uptake through thiamin transport system by growth study using an E. coli mutant incapable of synthesizing thiamin. The growth curves resulting show concentration-dependent growth in the absence of natural thiamin, indicating amino thiamin is taken up by thiamin transport system as an alternate source of thiamin for growth. More characterization of the thiamin transport system is desired in order to develop thiamin conjugates of interest such as a photoaffinity probe for isolating thiamin-utilizing enzymes.

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42

Wolak, Natalia. "Udział witaminy B_{1} w odpowiedzi na warunki stresu abiotycznego modelowych organizmów drożdżowych z rodzaju Saccharomyces oraz Candida." Praca doktorska, 2015. http://ruj.uj.edu.pl/xmlui/handle/item/42137.

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43

(5930339), Seda Tuncil. "Investigating Stability in Amorphous Solid Dispersions: A Study of the Physical and Chemical Stability of Two Salt Forms of Thiamine and the Physical Stability of Citric Acid." Thesis, 2019.

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The majority of water soluble vitamin and organic acid food additives are distributed in their crystalline forms. However, when they are combined with water and other food ingredients and then exposed to a variety of unit operations, there is potential to solidify these initially crystalline ingredients in the amorphous state. Amorphous solids are generally less chemically and physically stable than their crystalline counterparts. To ensure nutrient delivery to the consumer and fulfill labeling laws, deterioration of nutrients due to unintentional amorphization is undesirable. Additionally, the potential for recrystallization of an amorphous ingredient may alter texture and redistribute water. Hence, solid state form is a critical factor dictating the stability of food formulations. Building on earlier work from my M.S. degree that demonstrated thiamine chloride hydrochloride could solidify in the amorphous state in the presence of a variety of polymers (Arioglu-Tuncil et al., 2017), a major goal of this study was to develop a comprehensive understanding of the physical and chemical stability of amorphous forms of two thiamine salts, thiamine chloride hydrochloride (TClHCl) and thiamine mononitrate (TMN), in comparison to their crystalline counterparts and each other. The objectives for this part of the work were to investigate amorphization/recrystallization tendencies of TMN and TClHCl in solid dispersions, as well as chemical stability of thiamine in the solid dispersions to understand the impact of vitamin form, physical state (amorphous vs. crystalline), polymer type and features (Tg, hygroscopicity, and ability for intermolecular interactions), storage conditions, proportion of vitamin to polymer,and pre-lyophilized solution pHs on thiamine degradation and the physical stability of dispersions. Thiamine degraded more when in the amorphous form compared to in the crystalline state. Additionally, polymer type and vitamin proportion influenced thiamine degradation, where thiamine degraded more when it was present in lower concentrations (in dispersions that had higher Tgs), and it was chemically more stable when a polymer with greater intermolecular interactions with the vitamin was used. As storage RH increased, variably hygroscopicities of the polymers resulted in different thiamine degradation rates. The pre-lyophilization pHs of the solutions had a significant impact on thiamine stability in the solid dispersions. Similar to thiamine salts, citric acid is a commonly used food ingredient with a high crystallization tendency. Following similar experimental designs for documenting the recrystallization tendencies of citric acid in amorphous solid dispersions to those used in the thiamine studies, hydrogen bonding and/or ionic interactions between polymer and citric acid were found to be the main stabilizing factor for delaying recrystallization, more than polymer Tg and hygroscopicity. The findings of this dissertation provide a powerful prediction approach to physically and chemically stabilize the small compounds in the complex food matrices for the production of high quality food products and ensuring nutrient delivery to target populations.

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44

Digiorgio, Angela Marie. "Sensory and nutritional quality of boneless turkey rolls as affected by thermal processing conditions for foodservice usage." 1986. http://hdl.handle.net/2097/27617.

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45

Chadtová, Anežka. "Vývoj HPLC metody pro stanovení vitaminu B1 v klinickém výzkumu." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-344189.

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Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Anežka Chadtová Supervisor: RNDr. Lenka Kujovská Krčmová Ph.D. Title of diploma thesis: Development of HPLC method for determination of vitamin B1 in clinical research The present thesis describes the development and partial validation of the new HPLC method for determination of vitamin B1 (thiamine hydrochloride) and its phosphorylated derivatives (thiamine monophosphate, thiamine pyrophosphate). This method is based on the use of liquid chromatography with indirect fluorescence detection. Separation was achieved using modern second generation monolithic stationary phase High Resolution Chromolith RP-18e 100 x 4.6 mm (Merck, Germany) in combination with gradient elution. Mobile phase was consisting of the mixture of 95% phosphate buffer 10 mmol / l pH 6 5 and 5% acetonitrile (ACN), flow rate of the mobile phase was 2.5 ml / min, from 2.1. min 4 ml / min. For fluorescence detection of thiamin hydrochloride (TH), thiamin monophosphate (TMP) and thiamine pyrophosphate (TPP, thiamine diphosphate) was necessary to use chemical oxidation by potassium ferricyanide to thiochrome and its adequate esters having photoluminescence activity. Chromatographic method has been partially validated. Peak...

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46

Kumar, Gyanendra. "Computational And Biochemical Studies On The Enzymes Of Type II Fatty Acid Biosynthesis Pathway : Towards Antimalarial And Antibacterial Drug Discovery." Thesis, 2007. https://etd.iisc.ac.in/handle/2005/589.

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Malaria, caused by the parasite Plasmodium, continues to exact high global morbidity and mortality rate next only to tuberculosis. It causes 300-500 million clinical infections out of which more than a million people succumb to death annually. Worst affected are the children below 5 years of age in sub-Saharan Africa. Plasmodium is a protozoan parasite classified under the phylum Apicomplexa that also includes parasites such as Toxoplasma, Lankestrella, Eimeria and Cryptosporidium. Of the four species of Plasmodium affecting man viz., P. falciparum, P. vivax, P. ovale and P. malariae, Plasmodium falciparum is the deadliest as it causes cerebral malaria. The situation has worsened recently with the emergence of drug resistance in the parasite. Therefore, deciphering new pathways in the parasite for developing lead antimalarial compounds is the need of the hour. The discovery of the type II fatty acid biosynthesis pathway in Plasmodium falciparum has opened up new avenues for the design of new antimalarials as this pathway is different from the one in human hosts. Although many biochemical pathways such as the purine, pyrimidine and carbohydrate metabolic pathways, and the phospholipid, folate and heme biosynthetic pathways operate in the malaria parasite and are being investigated for their amenability as antimalarial therapeutic targets, no antimalarial of commercial use based on the direct intervention of these biochemical pathways has emerged so far. This is due to the fact that the structure and function of the targets of these drugs overlaps with that of the human host. A description of the parasite, its metabolic pathways, efforts to use these pathways for antimalarial drug discovery, inhibitors targeting these pathways, introduction to fatty acid biosynthesis pathway, discovery of type II fatty acid biosynthesis pathway in Plasmodium falciparum and prospects of developing lead compounds towards antimalarial drug discovery is given in Chapter 1 of the thesis. In the exploration of newly discovered type II fatty acid biosynthesis pathway of P. falciparum as a drug target for antimalarial drug discovery, one of the enzymes; β-hydroxyacyl- acyl carrier protein dehydratase (PfFabZ) was cloned and being characterized in the lab. The atomic structure of PfFabZ was not known till that point of time. Chapter 2 describes the homology modeled structure of PfFabZ and docking of the discovered inhibitors with this structure to provide a rationale for their inhibitory activity. Despite low sequence identity of ~ 21% with the closest available atomic structure then, E. coli FabA, a good model of PfFabZ could be built. A comparison of the modeled structure with recently determined crystal structure of PfFabZ is provided and design of new potential inhibitors is described. This study provides insights to further improve the inhibition of this enzyme. Enoyl acyl carrier protein reductase (ENR) is the most important enzyme in the type II fatty acid biosynthesis pathway. It has been proved as an important target for antibacterial as well as antimalarial drug discovery. The most effective drug against tuberculosis – Isoniazid targets this enzyme in M. tuberculosis. The well known antibacterial compound – Triclosan, a diphenyl ether, also targets this enzyme in P. falciparum. I designed a number of novel diphenyl ether compounds. Some of these compounds could be synthesized in the laboratory. Chapter 3 describes the design, docking studies and inhibitory activity of these novel diphenyl ether compounds against PfENR and E. coli ENR. Some of these compounds inhibit PfENR in nanomolar concentrations and EcENR in low micromolar concentrations, and many of them inhibit the growth of parasites in culture also. The structure activity relationship of these compounds is discussed that provides important insights into the activity of this class of compounds which is a step towards developing this class of compounds into an antimalarial and antibacterial candidate drugs. Components of the green tea extract and polyphenols are well known for their medicinal properties since ages. Recently they have been shown to inhibit components of the bacterial fatty acid biosynthesis pathway. Some selected tea catechins and polyphenols were tested in the laboratory for their inhibitory activity against PfENR. I conducted docking studies to find their probable binding sites in PfENR. On kinetic analysis of their inhibition, these compounds were found to be competitive with respect to the cofactor NADH. This has an implication that they could potentiate inhibition of PfENR by Triclosan in a fashion similar to that of NADH. As a model case, one of the tea catechins; EGCG ((-) Epigalocatechin gallate) was tested for this property. Indeed, in the presence of EGCG, the inhibition of PfENR improved from nanomolar to picomolar concentration of Triclosan.conducted molecular modeling studies and propose a model for the formation of a ternary complex consisting of EGCG, Triclosan and PfENR. Docking studies of these inhibitors and a model for the ternary complex is described in Chapter 4. Docking simulations show that these compounds indeed occupy NADH binding site. This study provides insights for further improvements in the usage of diphenyl ethers in conjugation or combination with tea catechins as possible antimalarial therapeutics. In search for new lead compounds against deadly diseases, in silico virtual screening and high throughput screening strategies are being adopted worldwide. While virtual screening needs a large amount of computation time and hardware, high throughput screening proves to be quite expensive. I adopted an intermediate approach, a combination of both these strategies and discovered compounds with a 2-thioxothiazolidin-4-one core moiety, commonly known as rhodanines as a novel class of inhibitors of PfENR with antimalarial properties. Chapter 5 describes the discovery of this class of compounds as inhibitors of PfENR. A small but diverse set of 382 compounds from a library of ~2,00,000 compounds was chosen for high throughput screening. The best compound gave an IC50 of 6.0 µM with many more in the higher micromolar range. The compound library was searched again for the compounds similar in structure with this best compound, virtual screening was conducted and 32 new compounds with better binding energies compared to the first lead and reasonable binding modes were tested. As a result, a new compound with an IC50 of 240 nM was discovered. Many more compounds gave IC50 values in 3-15 µM range. The best inhibitor was tested in red blood cell cultures of Plasmodium, it was found to inhibit the growth of the malaria parasite at an IC50 value of 0.75 µM. This study provides a new scaffold and lead compounds for further exploration towards antimalarial drug discovery. The summary of the results and conclusions of studies described in various chapters is given in Chapter 6. This chapter concludes the work described in the thesis. Cloning, over-expression and purification of PanD from M. tuberculosis, FabA and FabZ from E. coli are described in the Appendix.

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47

Kumar, Gyanendra. "Computational And Biochemical Studies On The Enzymes Of Type II Fatty Acid Biosynthesis Pathway : Towards Antimalarial And Antibacterial Drug Discovery." Thesis, 2007. http://hdl.handle.net/2005/589.

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Abstract:

Malaria, caused by the parasite Plasmodium, continues to exact high global morbidity and mortality rate next only to tuberculosis. It causes 300-500 million clinical infections out of which more than a million people succumb to death annually. Worst affected are the children below 5 years of age in sub-Saharan Africa. Plasmodium is a protozoan parasite classified under the phylum Apicomplexa that also includes parasites such as Toxoplasma, Lankestrella, Eimeria and Cryptosporidium. Of the four species of Plasmodium affecting man viz., P. falciparum, P. vivax, P. ovale and P. malariae, Plasmodium falciparum is the deadliest as it causes cerebral malaria. The situation has worsened recently with the emergence of drug resistance in the parasite. Therefore, deciphering new pathways in the parasite for developing lead antimalarial compounds is the need of the hour. The discovery of the type II fatty acid biosynthesis pathway in Plasmodium falciparum has opened up new avenues for the design of new antimalarials as this pathway is different from the one in human hosts. Although many biochemical pathways such as the purine, pyrimidine and carbohydrate metabolic pathways, and the phospholipid, folate and heme biosynthetic pathways operate in the malaria parasite and are being investigated for their amenability as antimalarial therapeutic targets, no antimalarial of commercial use based on the direct intervention of these biochemical pathways has emerged so far. This is due to the fact that the structure and function of the targets of these drugs overlaps with that of the human host. A description of the parasite, its metabolic pathways, efforts to use these pathways for antimalarial drug discovery, inhibitors targeting these pathways, introduction to fatty acid biosynthesis pathway, discovery of type II fatty acid biosynthesis pathway in Plasmodium falciparum and prospects of developing lead compounds towards antimalarial drug discovery is given in Chapter 1 of the thesis. In the exploration of newly discovered type II fatty acid biosynthesis pathway of P. falciparum as a drug target for antimalarial drug discovery, one of the enzymes; β-hydroxyacyl- acyl carrier protein dehydratase (PfFabZ) was cloned and being characterized in the lab. The atomic structure of PfFabZ was not known till that point of time. Chapter 2 describes the homology modeled structure of PfFabZ and docking of the discovered inhibitors with this structure to provide a rationale for their inhibitory activity. Despite low sequence identity of ~ 21% with the closest available atomic structure then, E. coli FabA, a good model of PfFabZ could be built. A comparison of the modeled structure with recently determined crystal structure of PfFabZ is provided and design of new potential inhibitors is described. This study provides insights to further improve the inhibition of this enzyme. Enoyl acyl carrier protein reductase (ENR) is the most important enzyme in the type II fatty acid biosynthesis pathway. It has been proved as an important target for antibacterial as well as antimalarial drug discovery. The most effective drug against tuberculosis – Isoniazid targets this enzyme in M. tuberculosis. The well known antibacterial compound – Triclosan, a diphenyl ether, also targets this enzyme in P. falciparum. I designed a number of novel diphenyl ether compounds. Some of these compounds could be synthesized in the laboratory. Chapter 3 describes the design, docking studies and inhibitory activity of these novel diphenyl ether compounds against PfENR and E. coli ENR. Some of these compounds inhibit PfENR in nanomolar concentrations and EcENR in low micromolar concentrations, and many of them inhibit the growth of parasites in culture also. The structure activity relationship of these compounds is discussed that provides important insights into the activity of this class of compounds which is a step towards developing this class of compounds into an antimalarial and antibacterial candidate drugs. Components of the green tea extract and polyphenols are well known for their medicinal properties since ages. Recently they have been shown to inhibit components of the bacterial fatty acid biosynthesis pathway. Some selected tea catechins and polyphenols were tested in the laboratory for their inhibitory activity against PfENR. I conducted docking studies to find their probable binding sites in PfENR. On kinetic analysis of their inhibition, these compounds were found to be competitive with respect to the cofactor NADH. This has an implication that they could potentiate inhibition of PfENR by Triclosan in a fashion similar to that of NADH. As a model case, one of the tea catechins; EGCG ((-) Epigalocatechin gallate) was tested for this property. Indeed, in the presence of EGCG, the inhibition of PfENR improved from nanomolar to picomolar concentration of Triclosan.conducted molecular modeling studies and propose a model for the formation of a ternary complex consisting of EGCG, Triclosan and PfENR. Docking studies of these inhibitors and a model for the ternary complex is described in Chapter 4. Docking simulations show that these compounds indeed occupy NADH binding site. This study provides insights for further improvements in the usage of diphenyl ethers in conjugation or combination with tea catechins as possible antimalarial therapeutics. In search for new lead compounds against deadly diseases, in silico virtual screening and high throughput screening strategies are being adopted worldwide. While virtual screening needs a large amount of computation time and hardware, high throughput screening proves to be quite expensive. I adopted an intermediate approach, a combination of both these strategies and discovered compounds with a 2-thioxothiazolidin-4-one core moiety, commonly known as rhodanines as a novel class of inhibitors of PfENR with antimalarial properties. Chapter 5 describes the discovery of this class of compounds as inhibitors of PfENR. A small but diverse set of 382 compounds from a library of ~2,00,000 compounds was chosen for high throughput screening. The best compound gave an IC50 of 6.0 µM with many more in the higher micromolar range. The compound library was searched again for the compounds similar in structure with this best compound, virtual screening was conducted and 32 new compounds with better binding energies compared to the first lead and reasonable binding modes were tested. As a result, a new compound with an IC50 of 240 nM was discovered. Many more compounds gave IC50 values in 3-15 µM range. The best inhibitor was tested in red blood cell cultures of Plasmodium, it was found to inhibit the growth of the malaria parasite at an IC50 value of 0.75 µM. This study provides a new scaffold and lead compounds for further exploration towards antimalarial drug discovery. The summary of the results and conclusions of studies described in various chapters is given in Chapter 6. This chapter concludes the work described in the thesis. Cloning, over-expression and purification of PanD from M. tuberculosis, FabA and FabZ from E. coli are described in the Appendix.

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48

Mehta, Rhea. "Investigting the Cytoprotective Mechanisms of VIitamins B6 and B1 against Endogenous Toxin-induced Oxidative Stress." Thesis, 2011. http://hdl.handle.net/1807/31865.

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Recent epidemiological evidence suggests that many chronic health disorders in the developed world are associated with endogenous toxins formed from the Western diet. The Western diet, which encompasses calorie dense foods, processed foods and increased quantities of red meat, can cause intracellular oxidative stress through increased formation of reactive oxygen species(ROS) and reactive carbonyl species (RCS). A number of micronutrients have been investigated for their protective capacity in in vitro and in vivo models of oxidative stress. This thesis investigated the cytotoxic targets of Fenton-mediated ROS and RCS and the subsequent protective mechanisms of vitamins B1 (thiamin) or B6 (pyridoxal, pyridoxamine or pyridoxine) in an isolated rat hepatocyte model. The approach was to use an “accelerated cytotoxicity mechanism screening” technique (ACMS) to develop an in vitro cell system that mimicked in vivo tissue cytotoxicity. Using this technique, we investigated the protective mechanisms of vitamins B1 and/or B6 against the cytotoxic effects of two endogenous toxins associated with the Western diet: 1) RCS, as exemplified by glyoxal, a glucose/fructose autoxidation product and 2) biological ROS induced by exogenous iron. Firstly, we developed an understanding of the sequence of events contributing to glyoxal-induced oxidative stress, with a focus on protein carbonylation. Next, we determined the mechanisms by which carbonyl scavenging drugs (vitamin B6 included) protected against the intracellular targets of glyoxal-induced toxicity. Our results suggested that the agents used were cytoprotective by multiple mechanisms and glyoxal trapping was only observed when the agents were administered at concentrations equal to glyoxal. We also evaluated the protective capacity of vitamins B1 and B6 against iron-catalyzed cytotoxicity and found that hepatocytes could be rescued from protein and DNA damage when vitamins B1 or B6 were added up to one hour after treatment with iron. The vitamins also varied in their primary mechanisms of protection. Our improved understanding of Western diet-derived endogenous toxins enabled us to identify and prioritize the specific inhibitory mechanisms of vitamins B1 or B6. The ability to delay, inhibit or reverse toxicity using multi-functional B1 or B6 vitamins could prove useful as therapy to minimize oxidative stress in diet-induced chronic conditions.

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49

Bedie, Kouadio Gerard. "Microencapsulation de composés nutraceutiques dans des complexes protéines-polysaccharides /." 2008. http://www.theses.ulaval.ca/2008/25147/25147.pdf.

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Dissertations / Theses on the topic 'Vitamin B1'

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