540 research outputs found

    Misreporting of energy and micronutrient intake estimated by food records and 24 hour recalls, control and adjustment methods in practice

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    In order to assess nutritional adequacy, valid estimates of nutrient intake are required. One of the main errors in dietary assessment is misreporting. The objective was to review the extent, nature and determinants of misreporting in dietary assessment, how this affects reported intakes of micronutrients and how this is identified and measured, and to identify the best ways of dealing with misreporting when interpreting results. A systematic literature search was conducted for studies of misreporting of dietary intake in adults by 24 hour recalls or by estimated or weighed food records, published up to March 2008. Thirty-seven relevant studies were identified. Possible causes of misreporting were identified. Methods most used to identify misreporting were the Goldberg cut-off (46 % studies) and the doubly labelled water technique (24 % studies). The magnitude of misreporting of energy intake was similar in all three dietary assessment methods. The percentage of under-reporters was about 30 % and energy intake was underestimated by approximately 15 %. Seven papers presented usable data for micronutrient intake. Absolute intakes of Fe, Ca and vitamin C (the three micronutrients addressed in all papers) were on average 30 % lower in low-energy reporters (LER) than that in non-LER and, although results were not consistent, there was a tendency for micronutrient density to be higher in LER. Excluding underreporters or using energy adjustment methods for micronutrient intakes is discussed. Residual method of energy adjustment seems to be a good tool for practice to decrease an influence of misreporting when interpreting results of studies based on food records and 24 hour recall

    IL6. Two-step model of ultrafast interfacial electron transfer in dye-semiconductor assemblies

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    Interfacial electron transfer (IET) is one of the steps in light-harvesting process that occurs in various assemblies for solar energy conversion, such as dye-sensitized solar cells or dye-sensitized photoelectrosynthesis cells. This work investigates IET in a model pyridine-TiO2 assembly, with the goals to assess the validity of the Fermi\u27s golden rule for calculation of the IET rates, understand the importance of conformational sampling in modeling the IET process, and establish an approach to rapid computational screening of dye-sensitizers that undergo fast IET into the semiconductor. Our results suggest that IET is a two-step process, in which the electron is first transferred into the semiconductor surface states, followed by the diffusion of the electron into the nanoparticle bulk states. Furthermore, while Fermi\u27s golden rule and related approaches are appropriate for predicting the initial IET rate (i.e., initial transfer of electron from dye into the semiconductor surface states), they are not reliable for prediction of the overall IET rate. Inclusion of the conformational sampling at room temperature into the model offers a more complete picture of the IET process, leading to a distribution of IET rates with the median rate faster than that of the IET rate obtained for the fully-optimized structure at 0 K. Finally, the two most important criteria for determination of the initial IET rate are the percent of electron density on linker in the excited state as well as the number of the semiconductor acceptor states available at the energy of the excited state. Both of these can be obtained from relatively simple electronic structure calculations either at ab initio or semiempirical levels of theory and can be thus used for rapid screening of dyes with desired properties. Elena Jakubikova, North Carolina State University Chang Liu, North Carolina State Universit

    Can sulforaphane prevent the onset or slow the progression of osteoarthritis?

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    Osteoarthritis (OA) is a degenerative joint disease characterised in part by destruction of articular cartilage. There are currently no disease-modifying drugs to treat OA, with joint replacement the only treatment offered to patients at end-stage disease. With age the major risk factor for OA, the number of patients is predicted to double by 2030. An understanding of the role of bioactive molecules from the habitual diet on joint health offers a novel way in which to prevent the onset or slow the progression of OA. Our research has indicated that sulforaphane (SFN), gained from the consumption of cruciferous vegetables, particularly broccoli, could impact upon articular cartilage in laboratory models of OA because (1) it decreased the cytokine-induced expression of cartilage-degrading proteinases from chondrocytes (cartilage cells); (2) it prevented the cytokine-induced degradation of cartilage explants; and (3) it attenuated cartilage destruction in a murine model of OA. The major mechanism of action for SFN in human articular chondrocytes was inhibition of NFB, not activation of Nrf2 nor inhibition of histone deacetylases. A proof-of-principle human trial was performed to measure uptake of SFN, or its metabolites, in the human knee joint following a broccoli-rich diet, and the expression or levels of several genes and proteins in cartilage, fat and synovial fluid were also measured. Data from this trial are about to be published. Overall, these findings support the utility of SFN in the prevention or treatment of OA. The proof of this requires an appropriately designed clinical trial of pain and function which we are currently pursuing

    Benefits and risks of the hormetic effects of dietary isothiocyanates on cancer prevention

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    The isothiocyanate (ITC) sulforaphane (SFN) was shown at low levels (1-5 µM) to promote cell proliferation to 120-143% of the controls in a number of human cell lines, whilst at high levels (10-40 µM) it inhibited such cell proliferation. Similar dose responses were observed for cell migration, i.e. SFN at 2.5 µM increased cell migration in bladder cancer T24 cells to 128% whilst high levels inhibited cell migration. This hormetic action was also found in an angiogenesis assay where SFN at 2.5 µM promoted endothelial tube formation (118% of the control), whereas at 10-20 µM it caused significant inhibition. The precise mechanism by which SFN influences promotion of cell growth and migration is not known, but probably involves activation of autophagy since an autophagy inhibitor, 3-methyladenine, abolished the effect of SFN on cell migration. Moreover, low doses of SFN offered a protective effect against free-radical mediated cell death, an effect that was enhanced by co-treatment with selenium. These results suggest that SFN may either prevent or promote tumour cell growth depending on the dose and the nature of the target cells. In normal cells, the promotion of cell growth may be of benefit, but in transformed or cancer cells it may be an undesirable risk factor. In summary, ITCs have a biphasic effect on cell growth and migration. The benefits and risks of ITCs are not only determined by the doses, but are affected by interactions with Se and the measured endpoint

    The ligand-to-metal charge transfer excited state of [Re(dmpe)3]2+

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    The ligand-to-metal charge transfer (LMCT) transitions of [Re(dmpe)3]2+ (dmpe=bis-1,2-(dimethylphosphino)ethane) were interrogated using UV/Vis absorbance spectroscopy, photoluminescence spectroscopy, and time-dependent density functional theory. The solvent dependence of the lowest energy charge transfer transition was quantified; no solvatochromism was observed. TD-DFT calculations reveal the dominant LMCT transition is highly symmetric and delocalized involving all phopshine ligand donors in the charge transfer, providing an understanding for the absence of solvatochromism of [Re(dmpe)3]2+

    Isocyanide Ligands Promote Ligand-to-Metal Charge Transfer Excited States in a Rhenium(II) Complex

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    A metal-to-ligand charge transfer with mixed intraligand character is observed for the rhenium hexakisarylisocyanide complex [Re(CNAr)6]PF6 (CNAr = 2,6-dimethylphenylisocyanide, λmax = 300 nm). Upon oxidation to [Re(CNAr)6](PF6)2, the dominant low energy optical transition is a ligand-to-metal charge transfer (LMCT) mixed with intraligand transitions (λmax = 650 nm). TD-DFT was used to identify the participating ligand-based orbitals in the LMCT transition, revealing that the majority of the donor orbital is based on the aryl ring (85%) as opposed to the CN bond (14%). For both [Re(CNAr)6]+ and [Re(CNAr)6]2+, structural characterization by X-ray diffraction reveals deviations from Oh geometry at the central Re ion, with larger reduction in symmetry observed for Re(II). For [Re(CNAr)6]+, these structural changes lead to a broadening of the strong ν(C≡N) stretch (2065 cm-1), as the degeneracy of the T1u IR-active mode is broken. Furthermore, a shoulder is observed for this ν(C≡N) stretch, resulting from deviation of the C-N-Ar bond from linearity. By contrast, [Re(CNAr)6]2+ has two weak bands in the ν(C≡N) region (2065 and 2121 cm-1). DFT calculations indicate that reduction of symmetry at the central rhenium ion manifests in the decrease in intensity and the observed split of the ν(C≡N) band. Stability of both complexes are limited by light-induced decomposition where Re(I) dissociates a isocyanide ligand upon irradiation and Re(II) absorbance decays under ambient light. These data provide new insights to the electronic structure of [Re(CNAr)6]2+, enhancing our understanding of LMCT excited states and the versatility of isocyanide ligands

    Wpływ zapalenia tarczycy Hashimoto, stężenia TSH oraz dodatniego wyniku obecności przeciwciał przeciwtarczycowych na występowanie zróżnicowanego raka tarczycy

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      Introduction: The relationship between Hashimoto’s thyroiditis (HT) and thyroid cancer (TC) is controversial. While most surgical studies report a high incidence of malignancy among patients with HT, cytological studies do not. The role of autoantibodies in the incidence of malignancy is unclear. Material and methods: A single-centre retrospective observational study was conducted in patients evaluated for thyroid nodules by US-guided fine-needle aspiration cytology (FNAC) and, if indicated, by surgery. The levels of thyroid-stimulating hormone (TSH) and anti-thyroid antibodies were measured at the time of FNAC. Results: Of 4947 patients, 599 (12.1%) were diagnosed with HT. A malignant/suspicious cytological result was found in 14.2% of the patients with HT and in 15.2% of the others. The odds ratio (OR) for malignancy in HT was 0.921 (0.716–1.183, p = 0.51). Of 1603 patients who underwent surgery, differentiated thyroid carcinoma was found in 29.5% of the HT patients and in 15.2% of the others (OR 2.33, 95% confidence interval CI, 1.403–3.854, p < 0,001). Low TSH (< 0.4 mIU/L) decreased the malignancy rate in the entire patient population, both when considering the cytological results and the surgical results. This was not confirmed in the subgroup diagnosed with HT. No relationship was observed between autoantibodies against thyroid peroxidase (ATP) or thyroglobulin (ATG) and malignancy rate. Conclusions: No association between HT and thyroid cancer was observed cytologically; a positive relationship in histological series was caused by selection bias. Low TSH levels decreased the risk of TC in patients with nodular goitre, but this has not been proven in patients with HT. (Endokrynol Pol 2016; 67 (1): 48–53)    Wstęp: Związek pomiędzy zapaleniem tarczycy Hashimoto (HT) i rakiem tarczycy (TC) jest uważany za kontrowersyjny. Podczas gdy większość badań nad operacjami dokumentuje wysoką częstotliwość występowania guzów wśród pacjentów z HT, badania cytologiczne tego nie potwierdzają. Rola autoprzeciwciał w częstotliwości występowania guzów nie jest do końca jasna. Materiał i metody: Wśród pacjentów, u których stwierdzono guzki tarczycy przeprowadzono jednoośrodkowe, retrospektywne badanie obserwacyjne poprzez aspiracyjną cytologię cienkoigłową (FNAC) pod kontrolą USG oraz operacyjnie, jeśli takie było wskazanie. Stężenia tyreotropiny (TSH) oraz przeciwciał przeciwtarczycowych zmierzono podczas przeprowadzania FNAC. Wyniki: Z 4947 pacjentów, u 599 (12,1%) zdiagnozowano HT. Zły/podejrzany wynik cytologii stwierdzono u 14,2% pacjentów z HT oraz u 15,2% innych pacjentów. Iloraz szans (OR) dla guza przy HT wynosił 0,921 (0,716–1,183, p = 0,51). Z 1603 pacjentów, których poddano operacji, zróżnicowanego raka tarczycy wykryto u 29,5% pacjentów z HT i u 15,2% innych pacjentów (OR 2,33; 95% CI; 1,403–3,854, p < 0,001). Niski poziom TSH (< 0,4 mIU/l) obniża wskaźnik występowania guza w całej populacji pacjentów, zarówno gdy bierze się pod uwagę wyniki cytologiczne, jak i operacyjne. Nie zostało to potwierdzone w podgrupie, u której zdiagnozowano HT. Nie zaobserwowano związku pomiędzy autoprzeciwciałami przeciw peroksydazie tarczycowej (ATP) lub tyreoglobulinie (ATG) i wskaźnikiem występowania guzów. Wnioski: Nie zaobserwowano cytologicznego związku pomiędzy HT i rakiem tarczycy; dodatni związek w seriach histologicznych spowodowany był stronniczością selekcji. Niskie stężenie TSH obniżył ryzyko TC u pacjentów z wolem guzkowym, lecz nie zostało to udowodnione u pacjentów z HT. (Endokrynol Pol 2016; 67 (1): 48–53)

    Phenethyl isothiocyanate, a dual activator of transcription factors NRF2 and HSF1

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    Cruciferous vegetables are rich sources of glucosinolates which are the biogenic precursor molecules of isothiocyanates (ITCs). The relationship between the consumption of cruciferous vegetables and chemoprotection has been widely documented in epidemiological studies. Phenethyl isothiocyanate (PEITC) occurs as its glucosinolate precursor gluconasturtiin in the cruciferous vegetable watercress (Nasturtium officinale). PEITC has multiple biological effects, including activation of cytoprotective pathways, such as those mediated by the transcription factor nuclear factor erythroid 2 p45-related factor 2 (NRF2) and the transcription factor heat shock factor 1 (HSF1), and can cause changes in the epigenome. However, at high concentrations, PEITC leads to accumulation of reactive oxygen species and cytoskeletal changes, resulting in cytotoxicity. Underlying these activities is the sulfhydryl reactivity of PEITC with cysteine residues in its protein targets. This chemical reactivity highlights the critical importance of the dose of PEITC for achieving on target selectivity, which should be carefully considered in the design of future clinical trials
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