1,313 research outputs found

    The influence of folic acid and vitamin B<SUB>12</SUB> on nucleic acid metabolism in microorganisms

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    A Mini-Review: Comparison between curcumin and tetrahydrocurcumin based on their activities

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    Curcumin, a natural ingredient present in turmeric rhizome is known for its various therapeutic activities such as antioxidant, anti-inflammatory, anticancer, antidiabetic, NF-kB activation suppresser. The hydrogenated derivative of curcumin, i.e., tetrahydrocurcumin, is also found to reveal the same activities. Moreover, the pro-oxidant effect of curcumin is reported, whereas tetrahydrocurcumin does not show any pro-oxidant effects. This contrasting behaviour of the two is attributed to their structures, because conjugation is involved only in curcumin, not in the tetrahydrocurcumin. It can be evidently concluded that double bonds affect the keto-enol ratio of the molecules and are therefore responsible for the degradation of curcumin, whereas tetrahydrocurcumin remains stable. Nevertheless, these double bonds are liable to affect the kinetics of beneficial activities of curcumin and tetrahydrocurcumin

    ANTIDEPRESSANT ACTIVITY OF AQUEOUS EXTRACTS OF FRUITS OF TERMINALIA CHEBULA AND PHYLLANTHUS EMBLICA IN BEHAVIOURAL MODELS OF DEPRESSION: INVOLVEMENT OF MONOAMINERGIC SYSTEM

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    Objectives: Terminalia chebula (TCh) and Phyllanthus emblica (PE) posses wide range of central nervous system activity. This study was conducted to investigate the antidepressant activity and mechanism action of aqueous extract of TCh &amp; PE using forced swimming test (FST) and tail suspension test (TST). Methods: Aqueous extracts of TCh (390, 780 &amp; 1560mg/kg) and PE (390, 780, 1560 &amp; 3120 mg/kg) were administered for seven days to mice and immobility time was measured in FST &amp; TST. Extracts were administered for 14 days and immobility time was measured in chronic FST. The mechanisms of antidepressant effect of TCh and PE were studied using prazosin (1mg/kg), levosulpiride (20mg/kg) and p-CPA (300mg/kg) in TST. Results: In FST, 780 &amp; 1560 mg/kg of TCh and 1560 &amp; 3120 mg/kg of PE reduced immobility time while in TST, 1560 mg/kg of TCh and 3120 mg/kg of PE decreased immobility significantly compared to control. In chronic FST, only 780 &amp; 1560 mg/kg of TCh showed significant reduction. Antidepressant effect of TCh was reversed by prazosin while antidepressant effect of PE was reversed by prazosin and levosulpiride significantly in TST. Conclusions: The aqueous extracts of TCh and PE possess antidepressant activity at higher doses. This effect was possibly mediated through mono aminergic pathways

    Structure-based stabilization of insulin as a therapeutic protein assembly via enhanced aromatic-aromatic interactions

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    Key contributions to protein structure and stability are provided by weakly polar interactions, which arise from asymmetric electronic distributions within amino acids and peptide bonds. Of particular interest are aromatic side chains whose directional π-systems commonly stabilize protein interiors and interfaces. Here, we consider aromatic-aromatic interactions within a model protein assembly: the dimer interface of insulin. Semi-classical simulations of aromatic-aromatic interactions at this interface suggested that substitution of residue TyrB26 by Trp would preserve native structure while enhancing dimerization (and hence hexamer stability). The crystal structure of a [TrpB26]insulin analog (determined as a T3Rf3 zinc hexamer at a resolution of 2.25 Å) was observed to be essentially identical to that of WT insulin. Remarkably and yet in general accordance with theoretical expectations, spectroscopic studies demonstrated a 150-fold increase in the in vitro lifetime of the variant hexamer, a critical pharmacokinetic parameter influencing design of long-acting formulations. Functional studies in diabetic rats indeed revealed prolonged action following subcutaneous injection. The potency of the TrpB26-modified analog was equal to or greater than an unmodified control. Thus, exploiting a general quantum-chemical feature of protein structure and stability, our results exemplify a mechanism-based approach to the optimization of a therapeutic protein assembly

    Thy-1 Expressing Mesenchymal Cells in Rat Nephrogenesis in Correlation with Cells Immunoreactive for α-Smooth Muscle Actin and Vimentin

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    Thy-1 expression may influence myofibroblast development. Through the epithelial-mesenchymal transition (EMT), injured renal epithelial cells undergo regression to the metanephric mesenchymal phenotype and then acquire a myofibroblastic nature (expressing α-smooth muscle actin; α-SMA). Because the metanephric blastema differentiates into mesenchymal and renal epithelial cells, we investigated Thy-1 immunoexpression during nephrogenesis in F344 rats in correlation with vimentin and α-SMA expressions. Kidney samples were obtained from fetuses on gestation days 18 and 21, neonates on days 1-18 and adults at 6 weeks of age. Mesangial cells in S-shaped bodies and immature and mature glomeruli continuously expressed both Thy-1 and α-SMA during early nephrogenesis (fetuses and neonates on days 1-9). During early nephrogenesis, loosely-arranged blastemal cell-derived mesenchymal cells in the cortex and medulla also exhibited Thy-1 and α-SMA, although the α-SMA expression was weaker than that of Thy-1. Vimentin expression coincided with that of Thy-1. These findings indicate that the derivation of α-SMA-expressing myofibroblastic cells may be related to mesangial or blastemal cells expressing both Thy-1 and α-SMA. Interestingly, there was a difference in Thy-1 expression between cortical and medullary tubulointerstitial cells from late nephrogenesis (neonates on days 12-18) and those from adults in that the cortical cells reacted faintly or negatively to Thy-1, whereas the medullary cells reacted strongly to Thy-1; additionally, bundle-arranged mesenchymal cells that were only observed in the neonates on days 1-12 reacted strongly to α-SMA, but faintly to Thy-1. Blastemal cell-derived mesenchymal cells seem to alter the immunoexpressions of Thy-1 and α-SMA, depending on the conditions which they develop. Thy-1 immunoexpression would be useful for investigation of reverse embryogenesis, which might occur in fibrotic kidneys

    Laser cladding of Ni based powder on a Cu-Ni-Al glassmold: Influence of the process parameters on bonding quality and coating geometry

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    International audienceLaser cladding of a Ni based powder on cupro-nickel-aluminum (Cu-Ni-Al) substrate was performed with a 4 kW continuous laser. The Cu-Ni-Al alloy is used for its thermal properties in glass mold industry. The role of the Ni based alloy clad is to protect the mold without affecting its thermal properties by limiting the heat-affected zone. The objective of this research is to produce a well bonded Ni based melted powder without pores or cracks and with a very small dilution zone on a non-planar surface (curved section). The impact of the process parameters such as laser power, scanning speed and powder feeding rate on the coating geometry was investigated with an experimental design technique analysis using the ANOVA (Analysis of variance) method. It was used to determine and represent the influence of each process parameter on the coating geometry (width, height) and the bonding quality. This ANOVA analysis led to a parameter combination to optimize the bonding quality between the Ni coating and the Cu-Ni-Al substrate taking into account the industrial geometrical constraints. More, an analytical calculation allowed to estimate the power necessary for bonding as a function of laser scanning speed and powder feeding rate

    Synergistic Antioxidant Activity of Capsicum Oleoresin, Lecithin and Curcuminoids in Sunflower Oil

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    Essential fatty acids (EFAs) have the tendency to undergo autoxidation. Hence, the addition of antioxidants becomes a key step during their storage. Synthetic antioxidants are found to be toxic in nature. Recently, many investigations were carried out where EFAs were stabilized by natural antioxidants those can even replace synthetic antioxidant totally. In the present study, capsicum oleoresin, soy lecithin and curcuminoids were used to stabilize EFAs in refined sunflower oil. The study showed that the synergism of these natural antioxidants in proper proportion increased the shelf life of sunflower oil. Consequently, the nutritive value of EFAs was restored because of their effective stabilization and the natural antioxidants added for their stabilization provided the medicinal benefits
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