No description available.

München, Techn. Universiẗat, Diss., 2001.

No description available.

No description available.

Background:  Betel nut (BN) or Areca nut (AN) chewing habits on its own or with other ingredients including chewing tobacco are highly prevalent in many South East Asian countries as well as among the migrants from these countries residing around the world. The major alcaloid arecoline in betel nut has been found to carcinogenic and to be associated with a range of health risks, including negative effects on pregnancy outcomes.  It is also reportedly associated with nutritional deficiencies including lower folate status among men and women. Pregnancy imposes stress on folate stores because of increased requirements for growth of maternal tissues, the fetus and the placenta.  Folate deficiency during pregnancy is a major public health concern as it is associated with many adverse health outcomes including neural tube defects, low birth weight, preterm birth, delayed maturation of the nervous system, growth retardation and megaloblastic anemia. Aim: To evaluate the association between betel nut use and folate status among pregnant women in Matlab, Bangladesh. Design: A secondary analysis of data from the Maternal and Infant Nutrition Intervention in Matlab (MINIMat) trial.  A sub sample of pregnant women aged 14-50 years and living in the study area Matlab with available serum folate measurements (N= 730) was included in this study. Outcome variable was folate level and folate deficiency and the independent variable was betel nut consumption.  Logistic regression analysis and analyses of covariance (ANCOVA) were done. Results were adjusted for potential confounders. Results: Two-thirds (63%) of the women consumed betel nut and 17% had folate deficiency. Women who consumed betel nut combined with  chewing  tobacco were 2.57 times more likely to have folate deficiency (OR = 2.57; 95% CI = 1.23-5.36; p =0.012;) and  betel nut consumption 2-3 times/day was significantly associated with folate deficiency among users (OR = 2.51; 95% CI = 1.07–5.92; p =0.035). Mean serum folate levels were significantly lower among betel nut users as compared to non-users. Conclusion: Betel nut consumption combined with chewing tobacco is associated with lower serum folate level or folate deficiency among pregnant women in Matlab in Bangladesh. Strategies are needed for prevention and control of betel nut consumption in order to prevent adverse health outcomes. There is a need of more knowledge regarding betel nut use and other combined substances to distinguish their individual effects on folate deficiency.

No description available.

O ácido fólico, a forma mais estável entre os folatos, é indicado como forma de prevenção sendo encontrado em forma de suplementação medicamentosa e alimentos fortificados, como leite e derivados. O folato pode reagir com a riboflavina singlete excitada, 1kq = 4,8·1010 L·mol-1·s-1, como determinado por desativação da fluorescência do estado estacionário, e com a riboflavina triplete excitada, com uma reação um pouco mais lenta, 3kq= 4,8·108 L·mol-1·s-1, como determinado por fotólise de pulso de laser e espectroscopia de absorção de transientes verificando-se que ambos os processos são competitivos e próximos ao limite de difusão. A preferência cinética de um a outro depende da matriz alimentar. O rendimento quântico para solução de riboflavina e de folato preparado em solvente aquoso e deuterado e em meio anaeróbico e aeróbico mostrou a prevalência do mecanismo fotoreacional do Tipo I. A voltametria cíclica apresentou um processo irreversível anódico de dois elétrons para o ácido fólico (E= 1,14 V vs. NHE). Os principais produtos da fotodegradação do folato sensibilizado pela riboflavina foram identificados por LC-IT-MS/MS como: 6-carboxipterina,p-aminobenzoil-L-ácido glutâmico e oxaziridina derivada do ácido fólico, como confirmando a desativação química do estado triplete excitado da riboflavina por transferência de elétrons com subseqüente clivagem oxidativa entre N(10) e C(9) no ácido fólico. / Folic acid, the most stable among folate, is recommended as prevention and it is found in supplementation and fortified foods such as milk and dairy products. The folate can react with singlet-excited state of riboflavin, 1kq= 4.8·1010 L·mol-1·s-1, as determined by steady-state fluorescence quenching, and with triplet-excited state of riboflavin in a slower reaction with 3kq= 4.8·108 L·mol-1·s-1, as determined by laser flash photolysis and transient absorption spectroscopy, verifying that both the processes are competitive and they are near limited diffusion. The kinetic preference depends on the matrix food. The quantum yield for the solution of riboflavin and folate prepared in aqueous and deuterated solvents and in anaerobic and aerobic medium showed the prevalence of the mechanism Type I. The cyclic voltammetry showed an irreversible two-electron anodic process for folate (E = 1.14 V vs. NHE). The main products of folate photodegradation sensitized by riboflavin were identified by LC-IT-MS/MS as: pterin-6-carboxylic acid, p-aminobenzoyl-L-glutamic acid and oxaziridine derivative of folic acid, as confirming chemical quenching of the triplet-excited state of riboflavin by electron transfer with subsequent oxidative cleavage between N(10) and C(9) in folic acid.

ABSTRACT THE RELATIONSHIP BETWEEN UNMETABOLIZED FOLIC ACID AND SERUM FOLATE CONCENTRATIONS AND CANCER RISK IN OLDER US ADULTS by Regine L. Baldauff Importance Several studies have reported an increase in serum and unmetabolized folic acid levels since the implementation of folic acid fortification (January 1, 1998). However, the literature published during the post-folic acid fortification period is controversial with regards to the safety and potential risk for cancer in non-target populations. Objective To study the association between unmetabolized folic acid and serum folate and cancer in older US adults. Design, Setting, and Participants This is a cross sectional study using data from National Health and Nutrition Examination Surveys. Among 700 participants with identified unmetabolized folic acid, 147 cases were reported a history of having cancer from 1999-2002. Within the 7,981 subjects who had a recorded value for serum folate from 1999-2008; 1,459 reported a history of all cancer. Among the 4,007 women who had a recorded value for serum folate between 1999-2008; 288 reported a history of breast cancer. Main Outcome Measures Associations of unmetabolized folic acid and serum folate with all cancer and breast cancer was evaluated using a multivariable logistic regression analysis controlling for demographic and dietary intakes. Results Men and women without unmetabolized folic acid were 0.7 times less likely to develop cancer. Those over the age of sixty with the highest concentration of serum folate were 1.4 times more likely to have cancer than participants with lower serum folate concentrations. Women over the age of sixty with the highest concentration of serum folate were 1.8 times more likely to have breast cancer compared to women with lower serum folate concentrations. Conclusions and Relevance The presence of unmetabolized folic acid and high serum folate concentrations were related to an increased prevalence of cancer. Further research is warranted to investigate the cause and effect relationship.

Folate is an essential cofactor in one-carbon transfer reactions including nucleotide biosynthesis, thereby playing an important role in DNA replication and repair. In cancer cells, folate depletion interrupts DNA synthesis, thereby causing cancer cell death. This has been the basis for chemotherapy using antifolates and 5-fluorouracil (5FU). We determined the effect of folate deficiency on the sensitivity of colon cancer cells to 5FU in a well established in vitro model of folate deficiency. Folate deficient cells had lower intracellular folate concentrations, had functional evidence of intracellular folate depletion, proliferated less, and had increased chemosensitivity to 5FU with and without Leucovorin. These data suggest that folate deficiency significantly enhances the sensitivity of colon cancer cells to 5FU based chemotherapy via changes in intracellular folate. Dietary or other strategies to deplete intracellular folate concentrations in colon cancer cells to enhance chemosensitivity to 5FU are worthy of further investigation.

Folate is an essential cofactor in one-carbon transfer reactions including nucleotide biosynthesis, thereby playing an important role in DNA replication and repair. In cancer cells, folate depletion interrupts DNA synthesis, thereby causing cancer cell death. This has been the basis for chemotherapy using antifolates and 5-fluorouracil (5FU). We determined the effect of folate deficiency on the sensitivity of colon cancer cells to 5FU in a well established in vitro model of folate deficiency. Folate deficient cells had lower intracellular folate concentrations, had functional evidence of intracellular folate depletion, proliferated less, and had increased chemosensitivity to 5FU with and without Leucovorin. These data suggest that folate deficiency significantly enhances the sensitivity of colon cancer cells to 5FU based chemotherapy via changes in intracellular folate. Dietary or other strategies to deplete intracellular folate concentrations in colon cancer cells to enhance chemosensitivity to 5FU are worthy of further investigation.