by Lui Ka Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 143-166). / Abstracts in English and Chinese. / Acknowledgements --- p.i / List of Abbreviations --- p.ii / Abstract --- p.iv / 摘要 --- p.viii / List of Tables --- p.xi / List of Figures --- p.xii / Contents --- p.xvii / Chapter CHAPTER 1 --- INTRODUCTION / Chapter 1.1 --- Sulfur-Containing Amino Acids --- p.1 / Chapter 1.2 --- Metabolism of Sulfur-Containing Amino Acids --- p.3 / Chapter 1.2.1 --- The Metabolic Pathways --- p.3 / Chapter 1.2.2 --- Metabolic Regulation of Homocysteine --- p.7 / Chapter 1.3 --- Sulfur-Containing Amino acids and Health --- p.10 / Chapter 1.3.1 --- Sulfur-Containing Amino Acids and Renal Diseases --- p.11 / Chapter 1.3.2 --- Sulfur-Containing Amino Acids and the Nervous System --- p.13 / Chapter 1.3.3 --- Sulfur-Containing Amino Acids and Heart Diseases --- p.16 / Chapter 1.3.4 --- Sulfur-Containing Amino Acids and Liver Diseases --- p.20 / Chapter 1.4 --- Vitamin C (Ascorbic Acid) --- p.21 / Chapter 1.4.1 --- Biosynthesis 、 --- p.23 / Chapter 1.4.2 --- Vitamin C Transport System --- p.24 / Chapter 1.4.2.1 --- Uptake of Ascorbic Acid --- p.25 / Chapter 1.4.2.2 --- Uptake of Dehydroascorbic Acid --- p.26 / Chapter 1.5 --- Vitamin C and Health --- p.28 / Chapter 1.5.1 --- Vitamin C and Heart Diseases --- p.28 / Chapter 1.5.2 --- Vitamin C and Renal Diseases --- p.29 / Chapter 1.5.3 --- Vitamin C and Brain Diseases --- p.30 / Chapter 1.5.4 --- Vitamin C and Liver Diseases --- p.31 / Chapter 1.6 --- The Aims of Project --- p.33 / Chapter CHAPTER 2 --- MATERIALS AND METHODS / Chapter 2.1 --- Materials --- p.35 / Chapter 2.2 --- Preparation of Materials --- p.37 / Chapter 2.2.1 --- Mobile Phase for Ascorbic Acid Analysis --- p.37 / Chapter 2.2.2 --- Mobile Phase for Amino Acid Analysis --- p.37 / Chapter 2.2.3 --- Reagents for RNA Extraction and Reverse Transcription- Polymerase Chain Reaction (RT-PCR) --- p.38 / Chapter 2.2.4 --- Sense and Antisense Primers --- p.38 / Chapter 2.2.5 --- Reagents for Electrophoresis --- p.40 / Chapter 2.3 --- Animals --- p.40 / Chapter 2.4 --- Experimental Studies --- p.41 / Chapter 2.5 --- Methods --- p.41 / Chapter 2.5.1 --- Ascorbic Acid Analysis --- p.41 / Chapter 2.5.1.1 --- Extraction of Ascorbic Acid --- p.41 / Chapter 2.5.1.2 --- Chromatography --- p.42 / Chapter 2.5.2 --- Amino Acid Analysis --- p.45 / Chapter 2.5.2.1 --- Sample Preparation --- p.45 / Chapter 2.5.2.2 --- Chromatography --- p.45 / Chapter 2.5.3 --- Determination of RNA Expression by RT-PCR Analysis --- p.50 / Chapter 2.5.3.1 --- RNA Isolation --- p.50 / Chapter 2.5.3.2 --- Measurement of RNA Yield --- p.51 / Chapter 2.5.3.3 --- Reverse Transcription --- p.51 / Chapter 2.5.3.4 --- Polymerase Chain Reaction (PCR) --- p.52 / Chapter 2.5.3.5 --- Separation of PCR Products by Agarose Gel Electrophoresis --- p.52 / Chapter 2.5.3.6 --- Quantification of Band Density --- p.53 / Chapter 2.6 --- Statistical Analysis --- p.53 / Chapter CHAPTER 3 --- RESULTS / Chapter 3.1 --- Effects of Sulfur-Containing Amino Acids and Leucine on Ascorbic Acid Distributions in Mice --- p.54 / Chapter 3.1.1 --- Effects of Sulfur-Containing Amino Acids and Leucine on Ascorbic Acid Concentrations in the Plasma --- p.55 / Chapter 3.1.2 --- Effects of Sulfur-Containing Amino Acids and Leucine on Ascorbic Acid Concentrations in the Kidney --- p.57 / Chapter 3.1.3 --- Effects of Sulfur-Containing Amino Acids and Leucine on Ascorbic Acid Concentrations in the Liver --- p.59 / Chapter 3.1.4 --- Effects of Sulfur-Containing Amino Acids and Leucine on Ascorbic Acid Concentrations in the Brain --- p.61 / Chapter 3.1.5 --- Effects of Sulfur-Containing Amino Acids and Leucine on Ascorbic Acid Concentrations in the Heart --- p.63 / Chapter 3.1.6 --- Summary --- p.65 / Chapter 3.2 --- Time-Response --- p.66 / Chapter 3.2.1 --- Effects of Sulfur-Containing Amino Acids and Leucine Administration for Various Periods on Ascorbic Acid Concentrations in the Plasma --- p.67 / Chapter 3.2.2 --- Effects of Sulfur-Containing Amino Acids and Leucine Administration for Various Periods on Ascorbic Acid Concentrations in the Kidney --- p.69 / Chapter 3.2.3 --- Effects of Sulfur-Containing Amino Acids and Leucine Administration for Various Periods on Ascorbic Acid Concentrations in the Liver --- p.71 / Chapter 3.2.4 --- Effects of Sulfur-Containing Amino Acids and Leucine Administration for Various Periods on Ascorbic Acid Concentrations in the Brain --- p.73 / Chapter 3.2.5 --- Effects of Sulfur-Containing Amino Acids and Leucine Administration for Various Periods on Ascorbic Acid / Chapter 3.2.6 --- Summary --- p.77 / Chapter 3.3 --- Effects of Sulfur-Containing Amino Acids and Leucine on SVCT and GLUT3 Gene Expressions --- p.78 / Chapter 3.3.1 --- Effects of Sulfur-Containing Amino Acids and Leucine Administration on SVCT mRNA Expression in the Kidney --- p.79 / Chapter 3.3.2 --- Effects of Sulfur-Containing Amino Acids and Leucine Administration on SVCT mRNA Expression in the Liver --- p.89 / Chapter 3.3.3 --- Effects of Sulfur-Containing Amino Acids and Leucine Administration on SVCT and GLUT3 mRNA Expression in the Brain --- p.98 / Chapter 3.3.4 --- Effects of Sulfur-Containing Amino Acids and Leucine Administration on SVCT mRNA Expression in the Heart --- p.109 / Chapter 3.3.5 --- Summary --- p.115 / Chapter 3.4 --- Sulfur-Containing Amino Acids Concentrations in the Plasma --- p.117 / Chapter 3.4.1 --- Effects of Administration of Sulfur-Containing Amino Acids and Leucine on Methionine Concentrations in the Plasma --- p.117 / Chapter 3.4.2 --- Effects of Administration of Sulfur-Containing Amino Acids and Leucine on Cystine Concentrations in the Plasma --- p.119 / Chapter 3.4.3 --- Effects of Administration of Sulfur-Containing Amino Acids and Leucine on Taurine Concentrations in the Plasma --- p.119 / Chapter 3.4.4 --- Effects of Administration of Sulfur-Containing Amino Acids and Leucine on Leucine Concentrations in the Plasma --- p.122 / Chapter 3.4.5 --- Summary --- p.124 / Chapter CHAPTER 4 --- DISCUSSION AND CONCLUSIONS / Chapter 4.1 --- Effects of Sulfur-Containing Amino Acids and Leucine on Ascorbic Acid Concentrations in Mice --- p.126 / Chapter 4.2 --- Effects of Sulfur-Containing Amino Acids and Leucine on SVCT and GLUT3 Gene Expressions --- p.131 / Chapter 4.3 --- Sulfur-Containing Amino Acids Concentrations in the Plasma --- p.136 / Chapter 4.4 --- Conclusions --- p.140 / REFERENCES --- p.143

MMed (Paediatrics), Faculty of Health Sciences, University of the Witwatersrand / This prospective observational study analysed iron studies and vitamin C levels in patients with chronic kidney disease attending Johannesburg Hospital Paediatric Nephrology Clinic. The rationale behind this study was to determine the extent of iron deficiency among patients in chronic renal failure. Vitamin C deficiency is common among dialysis patients, it is easy to test for and easy to prevent. This study may assist in guiding future management with regards to vitamin C supplementation in patients with chronic renal insufficiency on dialysis. The study contained 45 patients of which 27 (60 %) were male and 18 (40 %) were female. The ages of the children varied from 2 years 1 month to 19 years and 7 months. The study included patients from all ethnic groups; 9 were Caucasian, 33 African, 2 Indian and 1 Coloured. Two male patients did not have Vitamin C levels analyzed. The patients were divided into 3 distinct groups; firstly those patients on haemodialysis (12 patients), those on peritoneal dialysis (22 patients) and those not yet dialysed (11 patients). In all patients who were not yet on dialysis the GFR ranged between 18.1 and 45 ml/min/1.73m2. There were no statistically significant differences between the three groups when the results of the iron studies were analysed. However, despite iron treatment 26.6 % of patients were iron deficient as indicated by their transferrin saturation which was less than 20 %. Vitamin C levels were also analysed in this study. Forty one percent of children in chronic renal failure were vitamin C deficient. There was no statistically significant variability among the three groups. Two patients (4.6%) were noted to be Vitamin C toxic. One of these patients was haemodialysed; the other was not yet on dialysis. Vitamin C deficiency in chronic renal insufficient patients on dialysis is easily correctable when identified. Vitamin C in specific well documented doses is safe to administer to this group of patients. It will also enhance the absorption of iron and thereby have an indirect effect on anaemia.

"We have developed a system to rapidly create three-dimensional tissue rings from aggregated cells. The ability to use cell-derived tissues to screen the effects of culture conditions on tissue mechanical function has not previously been reported. The first goal of this study was to evaluate the mechanical properties of cell-derived tissue rings in response to ascorbic acid, which has been shown to increase collagen content, resulting in increased mechanical strength. The second goal was to develop quantitative methods to evaluate the structure and composition of cell-derived tissue rings. Rat aortic smooth muscle cells (1.33x10^6 cells/ring) were seeded in agarose wells with 4 mm post diameters in DMEM supplemented with 10% FBS and ascorbic acid (0, 50, 150 ug/ml). After 7 days, the average thickness of the constructs reached 0.72 +/- 0.03 mm with no statistical differences between groups. Ultimate tensile strength values were higher in the ascorbic acid-treated groups compared to untreated controls. However, there was no significant difference between tissue rings treated with 50 and 150 ug/ml ascorbic acid. Biochemical analysis showed that ascorbic acid did not significantly affect total protein, collagen content or cell number. Image analysis of polarized light micrographs suggested that collagen fibril coverage increased in response to ascorbic acid treatment, although the differences between groups were insignificant. In addition to ascorbic acid treatment, we also subjected tissue rings to DTPA treatment to prolong ascorbic acid availability in culture medium, which resulted in weak and necrotic tissue rings. Reduced serum was also investigated in order to decrease cell proliferation, which resulted in decreased tissue thickness and increased mechanical strength. Overall, we successfully demonstrated that the mechanical properties of the tissue rings could be altered by ascorbic acid treatment, and developed a series of quantitative methods to measure tissue mechanics, composition and organization. The results of this study further support the potential to use the tissue ring system as a high throughput screening method for studying the functional properties of three-dimensional engineered tissues."

Made available in DSpace on 2014-06-11T19:30:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-11-24Bitstream added on 2014-06-13T20:40:39Z : No. of bitstreams: 1 arruda_mf_dr_arafcf.pdf: 1544944 bytes, checksum: 75a1678618fc45bbed80bdb04d417b13 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A osteoartrose se caracteriza pela degeneração articular, perda de cartilagem e alterações no osso subcondral. Pouco se sabe sobre a patogênese e mudanças que ocorrem na osteoartrose como também em seu reparo. As técnicas terapêuticas disponíveis podem resultar em alívio dos sintomas, mas não na regeneração do tecido lesado. Um dos métodos usuais para pesquisa em osteoartrose com o preceito de mimetizar esta situação e também realizada neste trabalho, é o modelo experimental utilizando a inoculação intra-articular de zymosan (Saccharamyces cerevisiae), gerando artrite em grau progressivo. A eletroterapia potencializa a reparação de tecidos conjuntivos representando uma alternativa na reparação de lesões da cartilagem hialina. O acido ascórbico é um dos precurssores do colágeno que junto com outras estruturas complexas como a trama de glicosaminoglicanas e proteoglicanas constitui a cartilagem. A utilização dessa técnica para administração do acido ascórbico em tecido biológico é fator substancial do presente trabalho. Objetivo: O objetivo do presente estudo foi verificar a resposta imuno-bioquímica e avaliar microscopicamente a cartilagem articular de ratos artrose induzidos, frente ao tratamento com iontoforese na presença e ausência de acido L - ascórbico. Materiais e Métodos: Ratos wistar machos divididos em 6 grupos de 6 animais cada um, diferenciados em grupos: controle positivo C+, controle negativo C-,gavagem com solução fisiológica GSF, gavagem com ácido ascórbico GAA, iontoforese solução fisiológica IFSF iontoforese com ácido ascórbico IFAA.Resultados: Histológicos demonstraram em coloração Hematoxilina e Eosina que com o grupo IFAA obteve normalidade da variável celularidade (40.1 mm2), e manutenção da cartilagem não calcificada (75.5mm) (p<0.05), sugerindo espessuras normais. Quanto ao grupo não tratado C+ apresentou-se menor... / Osteoarthritis is characterized by joint degeneration, loss of cartilage and subchondral bone changes. Little is known about the pathogenesis and changes that occur in osteoarthritis as well as in its repair. Available therapeutic techniques can result in relief of symptoms but not in the regeneration of injured tissue. One of the usual methods for research used in this study is the experimental model which uses intra-articular inoculation of zymosan (Saccharamyces cerevisiae), causing arthritis in progressive degree. Electrotherapy enhances the healing of tissues representing an alternative in the repair of hyaline cartilage injuries. Ascorbic acid is one of the forerunners of collagen which along with other complex structures like the chains of glycosaminoglycans and proteoglycans form the cartilage. The use of this technique for administration of ascorbic acid in biological tissue is a substantial factor in this study. Objective: The objective of this study was to investigate the immune-biochemical reply and evaluate microscopically the histology of articular cartilage in rats arthritis induced, compared to treatment with iontophoresis in the presence and absence of L - ascorbic acid. Methods: Male wistar rats were divided into 6 groups of 6 animals each, in different groups: positive control C+, negative control C-, gavage with saline solution GSS, gavage with ascorbic acid GAA, saline iontophoresis IPSS, iontophoresis with ascorbic acid IPAA. Results: Histological it was demonstrated that in hematoxylin and eosin staining the group that received IPAA obtained normality of variable (40.1 mm2), and maintenance of non calcified cartilage (75.5mm) (p<0.05), suggesting normal thickness. Regarding the untreated group C+, it presented lower average in the number of chondrocytes (13.0mm2), and with regard to the thickness of cartilage it had a higher average of calcified cartilage with... (Complete abstract click electronic access below)

Applesauce prepared for the US military is processed as MRE (meals-ready-to-eat) in several forms including Type VI - Applesauce with raspberry puree, and Type VII - Carbohydrate enriched applesauce. Production of MRE applesauce starts with commercially prepared and thermally processed applesauce that is further processed by a military contractor. The further processing includes adjusting pH, ºBrix, and ascorbic acid level, packaging into pouches, and again thermally processing. Both types of the MRE applesauce are very much liked by troops, but under stress storage applesauce darkens and its consumption is drastically reduced. The overall goal of this project was to identify additives to be used during further processing in order to slow darkening when exposed to elevated temperatures during shipping and storage. The specific objective was to determine whether different types of ascorbic acid, calcium salts, or addition of chelators can reduce deterioration under stress storage. Applesauce (AS), applesauce with raspberry puree (RPAS), MRE AS (Type VII) and MRE RPAS (Type VI) for all experiments were provided by Sopakco, Bennettsville S.C. The research was carried out in three phases. From the Phase 1, we learned that Type VII and Type VI darkened at faster rates at the beginning of the storage, but the effects of storage at 50°C for more than 2 weeks overcame any differences caused by further processing. Phase 2 helped us determine the formulations for the processing on the industrial scale. The formulations were: 0.15% L-ascorbic-acid (AA), and 0.15% AA with 300 ppm EDTA for both AS and RPAS, with 0.83% calcium lactate gluconate (CLG) for AS, and 0.15% ascorbyl-palmitate for RPAS. The results from the Phase 3 indicated that AS with addition of CLG and RPAS with total of 0.18% AA had the least total color change. In all samples, accumulation of HMF was related to amount of ascorbic acid with exception of samples with Pal which had the lowest HMF content. Our results indicate that current MRE Types VI and VII may have better stability at stress storage if the level of AA is limited to 0.18% and 0.83% CLG is added to the AS formulation.

The antioxidant and redox properties of L-ascorbic acid are closely associated with the electron rich 2, 3-enediol moiety of the molecule and therefore selective functionalization of the 2- and 3-OH groups is essential for the detailed structure-activity studies. Reactions of 5- and 6-OH protected ascorbic acid with electrophilic reagents exclusively produce the corresponding 3-O-alkylated products under mild basic conditions due to the high nucleophilicity of the C-3-OH. Based on the density functional theory (B3LYP) electron density calculations, a novel and general method was devised for the direct alkylation of the 2-OH group of ascorbic acid with complete regio- and chemo-selectivity. A complete spectroscopic analysis of two complementary series of 2- O -acetyl-3- O -alkyl and 2- O -alkyl-3- O -acetyl ascorbic acid derivatives was carried out to define their spectroscopic characteristics and to resolve common inconsistencies in the literature. The asymmetric approach to the synthesis of natural products or other biologically active compounds is impeded by low abundance of natural sources as well as a limited number of efficient synthetic methods. Nevertheless, carbohydrate-based systems such as the aldono-1,4-lactones (also known as aldono-γ-lactones) which generate a host of chiral compounds have been particularly rewarding in this respect. This study shows a practical approach using 5,6- O -isopropylidene-L-ascorbic acid (ketal of L-ascorbic acid) as a single common starting material for facile asymmetric synthesis of protected, optically pure and functionalized aldono-1,4-lactones derivatives, valuable in the synthesis of derivatives of various pharmacologically active agents for structure-activity studies. The practicality of this new approach is demonstrated by the convenient synthesis of a series of thermal Claisen-rearranged products of 5,6- O -isopropylidene-3- O -allyl-L-ascorbic acid and 5,6- O -isopropylidene-2- O -allyl-L-ascorbic acid as the corresponding 5,6- O -isopropylidene-2-allyl-3-keto-L-galactono-γ-lactone and 5,6- O -isopropylidene-3-allyl-2-keto-L-galactono-γ-lactone respectively. The synthetic routes are economical, efficient, diastereospecific, and proceed in high yields. / "August 2005." / Thesis (Ph.D.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Chemistry.

No description available.

Vitamin C is an essential water soluble vitamin found mainly in fruits, vegetables and their derivatives. Orange juice is a popular thirst quencher and a convenient way to reach the daily recommended intake of vitamin C. The aim of this thesis was to determine how the vitamin C content in orange juice is affected by storage temperature and oxygen content in the product. Bottles of orange juice were stored at different temperatures. Regular orange juice was compared to juice where dissolved oxygen in product water had been decreased before mixing the juice. One other aim was to determine the efficiency of a stress test room where a higher temperature was supposed to simulate longer storage time. The study showed a larger non-linear loss of vitamin C over time in the bottles stored at the higher temperatures. The samples with less dissolved oxygen showed a higher vitamin C content after five and six months of storage in room temperature. For a storage time up to one week the loss of vitamin C in the stress test does not appear to be equal to the corresponding storage time in room temperature.KeywordsOrange juice, / Vitamin C är en livsnödvändig vattenlöslig vitamin som främst förekommer i grönsaker, frukter och produkter framställda från dessa. Apelsinjuice är en populär törstsläckare och ett enkelt sätt att få i sig sin dagliga dos C-vitamin. Syftet med denna rapport är att undersöka hur halten C-vitamin i apelsinjuice från Kiviks Musteri ändras beroende på lagringstemperatur och syrehalt i produktvatten. Apelsinjuice tillverkad från kranvatten jämfördes med juice tillverkad med vatten där syrehalten minskats genom kokning. Ett annat syfte var att fastställa effektiviteten för ett lagringsrum som simulerade en längre lagringsperiod genom att höja temperaturen. Resultaten visade att det var en större ickelinjär förlust av C-vitamin i flaskor som lagras vid en högre temperatur. Juiceflaskor med mindre mängd löst syre visade en lägre förlust av C-vitamin efter fem respektive sex månaders lagring i rumstemperatur. Förlusten av C-vitamin i juice lagrad en vecka i rummet med högre temperatur var ej den mängd som förutspåddes enligt företagets modell.

Ascorbic acid (AA), in popular speech vitamin C, is a commonly known nutrient. It is involved in several biological processes and deficiency can lead to scurvy. Recent publications have shown the impact of AA on epigenetic regulation in mice. Addition of AA, via enzymatic activity, enhances the generation of 5-hydroxymethylcytosine (5hmC), which is an intermediate in active demethylation of DNA. The role of AA on epigenetic changes in humans has to our knowledge never been studied. In this study, naïve CD4+ T cells from blood donors were used as a model system to investigate AAs possible role in methylation changes in the immune system. By using dot-blot assay, hydroxymethylated DNA immunoprecipitation (hmeDIP) and qPCR, changes in methylation executed by AA could be detected. A confirmation of AAs impact on epigenetic changes in mice was observed. AA enhanced the levels of 5hmC compared to untreated cells. The Jurkat cell line, a human T lymphocyte cell line, showed an opposite result. Treatment with AA decreased the levels of 5hmC compared to untreated cells. When comparing this result with the results obtained in human naïve T cells, the same observation was made. The difference between mouse and human in the ability of producing and metabolize AA could be a reason for this opposite result. Since AA had the ability to modify epigenetic changes in primary human CD4+ T cells, the results suggest that AA may have a function in the human immune system.

Diss. (sammanfattning) Umeå : Umeå universitet, 2006. / Härtill 5 uppsatser.