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Displaying article 1-24
p. 1-13
Received: 28 October 2009; in revised form: 23 November 2009 / Accepted: 23 December 2009 / Published: 24 December 2009
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| Download PDF Full-text (185 KB) | Download XML Full-text Abstract: Chalcones exhibit chemopreventive and antitumor effects. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a naturally occurring anticancer agent that induces apoptosis in cancer cells and is not toxic to normal cells. We examined the cytotoxic and apoptotic effect of five chalcones in combination with TRAIL on prostate cancer cells. The cytotoxicity was evaluated by the MTT and LDH assays. The apoptosis was determined using flow cytometry with annexin V-FITC. Our study showed that all five tested chalcones: chalcone, licochalcone-A, isobavachalcone, xanthohumol, butein markedly augmented TRAIL-mediated apoptosis and cytotoxicity in prostate cancer cells and confirmed the significant role of chalcones in chemoprevention of prostate cancer.
p. 14-40
Received: 19 November 2009; in revised form: 19 December 2009 / Accepted: 24 December 2009 / Published: 28 December 2009
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| Download PDF Full-text (404 KB) | Download XML Full-text Abstract: This review will discuss recent progress in the chemistry of secondary polyphenols produced during food processing. The production mechanism of the secondary polyphenols in black tea, whisky, cinnamon, and persimmon fruits will be introduced. In the process of black tea production, tea leaf catechins are enzymatically oxidized to yield a complex mixture of oxidation products, including theaflavins and thearubigins. Despite the importance of the beverage, most of the chemical constituents have not yet been confirmed due to the complexity of the mixture. However, the reaction mechanisms at the initial stages of catechin oxidation are explained by simple quinone–phenol coupling reactions. In vitro model experiments indicated the presence of interesting regio- and stereoselective reactions. Recent results on the reaction mechanisms will be introduced. During the aging of whisky in oak wood barrels, ellagitannins originating from oak wood are oxidized and react with ethanol to give characteristic secondary ellagitannins. The major part of the cinnamon procyanidins is polymerized by copolymerization with cinnamaldehyde. In addition, anthocyanidin structural units are generated in the polymer molecules by oxidation which accounts for the reddish coloration of the cinnamon extract. This reaction is related to the insolubilization of proanthocyanidins in persimmon fruits by condensation with acetaldehyde. In addition to oxidation, the reaction of polyphenols with aldehydes may be important in food processing.
p. 41-51
Received: 30 October 2009; in revised form: 3 December 2009 / Accepted: 28 December 2009 / Published: 29 December 2009
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| Download PDF Full-text (208 KB) | Download XML Full-text Abstract: Different concentrations of asafoetida extract were added to the medium of Pleurotus ferulic and the effects of the extract on growth of P. ferulic mycelium and fruiting bodies was observed. As the amount of asafoetida extract additive was increased, the growth of Pleurotus mycelium was faster, the time formation of buds was shorter and that yield of fruiting bodies was stimulated. However, overdosing of asafoetida extract hampered the growth of Pleurotus ferulic. The amino acid composition and volatile components in three kinds of pleurotus’ were contrasted, including wild pleurotus (WP), cultivated pleurotus with asafoetida extract (CPAE) and cultivated pleurotus without asafoetida extract (CP). CPAE with 2.3 g/100 g asafoetida extract addition had the highest content of total amino acids, as well as essential amino acids. WP had a higher content of total amino acids and essential amino acids than CP. In addition, CPAE with 2.3 g/100 g had the highest score of protein content of pleurotus fruiting bodies, while WP had a higher score than CP. In the score of essential amino acid components of pleurotus fruiting bodies, CP had the highest score, while CPAE was higher than WP. Asafoetida extract influenced the volatile components of Pleurotus ferulic greatly, making the volatile components of cultivated pleurotus more similar to those of wild pleurotus (WP).
p. 52-66
Received: 31 October 2009; in revised form: 25 December 2009 / Accepted: 28 December 2009 / Published: 5 January 2010
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| Download PDF Full-text (1781 KB) | Download XML Full-text Abstract: Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of heart muscles. Here we show a novel biomimetic gel actuator that can walk spontaneously with a wormlike motion without switching of external stimuli. The self-oscillating motion is produced by dissipating chemical energy of oscillating reaction. Although the gel is completely composed of synthetic polymer, it shows autonomous motion as if it were alive.
p. 67-78
Received: 16 December 2009 / Accepted: 30 December 2009 / Published: 6 January 2010
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| Download PDF Full-text (390 KB) | Download XML Full-text Abstract: Dandelion (Taraxacum officinale ), an oriental herbal medicine, has been shown to favorably affect choleretic, antirheumatic and diuretin properties. Recent reports have indicated that excessive oxidative stress contributes to the development of atherosclerosislinked metabolic syndrome. The objective of this current study was to investigate the possible hypolipidemic and antioxidative effects of dandelion root and leaf in rabbits fed with a high-cholesterol diet. A group of twenty eight male rabbits was divided into four subgroups; a normal diet group, a high-cholesterol diet group, a high-cholesterol diet with 1% (w/w) dandelion leaf group, and a high-cholesterol diet with 1% (w/w) dandelion root group. After the treatment period, the plasma antioxidant enzymes and lipid profiles were determined. Our results show that treatment with dandelion root and leaf positively changed plasma antioxidant enzyme activities and lipid profiles in cholesterol-fed rabbits, and thus may have potential hypolipidemic and antioxidant effects. Dandelion root and leaf could protect against oxidative stress linked atherosclerosis and decrease the atherogenic index.
p. 79-106
Received: 21 November 2009; in revised form: 25 December 2009 / Accepted: 2 January 2010 / Published: 6 January 2010
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| Download PDF Full-text (448 KB) | Download XML Full-text Abstract: Plant tannins, including hydrolysable and condensed varieties, are well known antioxidants in medicinal plants, foods, and edible fruits. Their diverse biological properties and potential for disease prevention have been demonstrated by various in vitro and in vivo assays. A number of ellagitannins, the largest group of hydrolysable tannins, have been isolated from dicotyledoneous angiosperms and characterized. This diverse class of tannins is sub-grouped into simple ellagitannins, C -glycosidic ellagitannins, complex tannins (condensates of C -glycosidic tannins with flavan-3-ol), and oligomers up to pentamers. This review outlines and describes the chemotaxonomic significance of structural features in various types of ellagitannins found in plants belonging to the Myrtaceae, Onagraceae, and Melastomataceae families, which are all included in the order Myrtales. Any biological activities that have been reported, including antitumor and antibacterial effects as well as enzyme inhibition, are also reviewed.
p. 107-123
Received: 4 November 2009; in revised form: 31 December 2009 / Accepted: 1 January 2010 / Published: 8 January 2010
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| Download PDF Full-text (201 KB) | Download XML Full-text Abstract: Standardized extract from the leaves of the Ginkgo biloba tree, labeled EGb761, is one of the most popular herbal supplements. Numerous preclinical studies have shown the neuroprotective effects of EGb761 and support the notion that it may be effective in the treatment and prevention of neurodegenerative disorders such as Alzheimer’s disease (AD). Despite the preclinical promise, the clinical efficacy of this drug remains elusive. In this review, possible mechanisms underlying neuroprotective actions of EGb761 are described in detail, together with a brief discussion of the problem of studying this herb clinically to verify its efficacy in the treatment and prevention of AD. Moreover, various parameters e.g., the dosage and the permeability of the blood brain barrier (BBB), impacting the outcome of the clinical effectiveness of the extract are also discussed. Overall, the findings summarized in this review suggest that, a better understanding of the neuroprotective mechanisms of EGb761 may contribute to better understanding of the effectiveness and complexity of this herb and may also be helpful for design of therapeutic strategies in future clinical practice. Therefore, in future clinical studies, different factors that could interfere with the effect of EGb761 should be considered.
p. 124-139
Received: 25 November 2009; in revised form: 6 January 2010 / Accepted: 6 January 2010 / Published: 8 January 2010
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| Download PDF Full-text (167 KB) | Download XML Full-text Abstract: The genetic variation found in small regions of the genomes of many species can be arranged into haplotype trees that reflect the evolutionary genealogy of the DNA lineages found in that region and the accumulation of mutations on those lineages. This review demonstrates some of the many ways in which clades (branches) of haplotype trees have been applied in recent years, including the study of genotype/phenotype associations at candidate loci and in genome-wide association studies, the phylogeographic history of species, human evolution, the conservation of endangered species, and the identification of species.
p. 140-153
Received: 13 November 2009; in revised form: 4 January 2010 / Accepted: 7 January 2010 / Published: 12 January 2010
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| Download PDF Full-text (478 KB) | Download XML Full-text Abstract: Transient forebrain or global ischemia induces cell death in vulnerable CA1 pyramidal neurons. A brief period of ischemia, i.e. , ischemic preconditioning, affords CA1 neurons robust protection against a subsequent, more prolonged ischemic challenge. Using the four-vessel occlusion model, we established an ischemic preconditioning model in which rodents were subjected to 3 min of sublethal ischemia 48 h before a 15 min lethal ischemia. We showed that preconditioning attenuated the ischemia-induced neural cell death and DNA fragmentation in the hippocampal CA1 region. RT-PCR and western blot analysis showed that preconditioning prior to an ischemic insult significantly increased ASIC 2a mRNA and protein expression in comparison to the ischemic insult alone (p < 0.01). These findings implicate a new role of ASIC 2a on endogenous neuroprotection from ischemic insult.
p. 154-163
Received: 14 December 2009; in revised form: 30 December 2009 / Accepted: 5 January 2010 / Published: 12 January 2010
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| Download PDF Full-text (365 KB) | Download XML Full-text Abstract: Imagine devices or particles so small that they are invisible to the naked eye. Imagine that such entities could be used to patrol our bodies and autonomously augment endogenous defense and repair mechanisms. Imagine the defeat of illness at a fraction of the current costs. Bionanotechnology is the field of science that deals with just that: the development of imaging, tracking, targeting, sensing, diagnostic, and eventually therapeutic capabilities based on particles in the nanometer range, i.e. , “nanoparticles”. Within the extensive group of nanoparticles, semiconducting quantum dots play a central and prominent role. Quantum dots excel at a myriad of physical properties, most notably their fluorescent properties, such as high quantum yield, photo-stability, broad absorption spectra, and their remarkable size-dependent emission-tunability.
p. 164-172
Received: 16 December 2009; in revised form: 5 January 2010 / Accepted: 6 January 2010 / Published: 13 January 2010
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| Download PDF Full-text (947 KB) | Download XML Full-text Abstract: A novel type of high-pressure membrane reactor has been developed for hydrogenation in supercritical carbon dioxide (scCO2 ). The main objectives of the design of the reactor are the separate feeding of hydrogen and substrate in scCO2 for safe reactions in a continuous flow process, and to reduce the reaction time. By using this new reactor, hydrogenation of cinnamaldehyde into hydrocinnamaldehyde has been successfully carried out with 100% selectivity at 50 °C in 10 MPa (H2 : 1 MPa, CO2 : 9 MPa) with a flow rate of substrate ranging from 0.05 to 1.0 mL/min.
p. 173-188
Received: 1 December 2009; in revised form: 31 December 2009 / Accepted: 4 January 2010 / Published: 12 January 2010
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| Download PDF Full-text (474 KB) | Download XML Full-text Abstract: The host-guest complexation between an Alexa 488 labelled adamantane derivative and β-cyclodextrin is studied by Fluorescence Correlation Spectroscopy (FCS). A 1:1 complex stoichiometry and a high association equilibrium constant of K = 5.2 × 104 M-1 are obtained in aqueous solution at 25 °C and pH = 6. The necessary experimental conditions are discussed. FCS proves to be an excellent method for the determination of stoichiometry and association equilibrium constant of this type of complexes, where both host and guest are nonfluorescent and which are therefore not easily amenable to standard fluorescence spectroscopic methods.
p. 189-205
Received: 30 November 2009 / Accepted: 17 December 2009 / Published: 12 January 2010
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| Download PDF Full-text (598 KB) | Download XML Full-text Abstract: Aqueous solutions of ethoxylated alcohols which form lyotropic liquid crystals at high concentrations (40–80%) were selected as model lubricating substances. Microscopic studies under polarized light and viscosity measurements were carried out in order to confirm the presence of liquid crystalline structures in the case of alcohol solutions with ethoxylation degrees of 3, 5, 7 and 10. Microscopic images and viscosity coefficient values characteristic of various mesophases were obtained. As expected, the viscosity of LLCs decreases considerably with an increase in shearing rate which is characteristic of liquid crystals being non-Newtonian liquids. Antiseizure properties were determined by means of a four-ball machine (T-02 Tester) and characterized by scuffing load (Pt ), seizure load (Poz ) and limiting pressure of seizure (poz ). Alcohol ethoxylates forming mesophases in aqueous solutions have the strongest effect on the Pt values which are several times higher than those measured in the presence of water. Ethoxylates with higher degrees of ethoxylation exhibit higher values of scuffing load. Those changes have been interpreted as a result of higher cloud points at which those compounds lose their amphiphilic properties. In general, the presence of mesophases in the bulk phase and particularly in the surface phase may lead to the formation of a lubricant film which separates the frictionally cooperating elements of a friction pair. The antiseizure efficiency of alcohol solutions is highest up to the load value which does not exceed the scuffing load value.
p. 206-221
Received: 24 November 2009; in revised form: 4 January 2010 / Accepted: 8 January 2010 / Published: 13 January 2010
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| Download PDF Full-text (4123 KB) | Download XML Full-text Abstract: Recent advances in nanophotonics open the way for promising applications towards efficient single molecule fluorescence analysis. In this review, we discuss how photonic methods bring innovative solutions for two essential questions: how to detect a single molecule in a highly concentrated solution, and how to enhance the faint optical signal emitted per molecule? The focus is set primarily on the widely used technique of fluorescence correlation spectroscopy (FCS), yet the discussion can be extended to other single molecule detection methods.
p. 222-232
Received: 16 December 2009; in revised form: 8 January 2010 / Accepted: 10 January 2010 / Published: 13 January 2010
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| Download PDF Full-text (208 KB) | Download XML Full-text Abstract: The extracellular signal-regulated kinase (ERK) pathway is a member of the mitogen-activated protein kinase (MAPK) superfamily, which is an important, highly conserved family of enzymes associated with cell membrane receptors and regulative targets. In the central nervous system, there is almost no mature neuronal proliferation and differentiation, but the regulation of MAPK and its upstream and downstream molecular pathways is still widespread, with the ERK signaling pathway being one of the most actively studied signal transduction pathways. It is activated by a variety of cell growth factors and substances which promote mitotic activity, and transmits extracellular signals from the cell surface to the nucleus, which transmission plays an important role in the process of cell proliferation and differentiation. In recent years, accumulating evidence has shown that the ERK signaling pathway has an important link with the higher functions of learning and memory.
p. 233-253
Received: 23 November 2009; in revised form: 7 January 2010 / Accepted: 9 January 2010 / Published: 19 January 2010
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| Download PDF Full-text (198 KB) | Download XML Full-text Abstract: Different types of enzymes such as lipases, several phosphatases, dehydrogenases, oxidases, amylases and others are well suited for the reactions in SC-CO2 . The stability and the activity of enzymes exposed to carbon dioxide under high pressure depend on enzyme species, water content in the solution and on the pressure and temperature of the reaction system. The three-dimensional structure of enzymes may be significantly altered under extreme conditions, causing their denaturation and consequent loss of activity. If the conditions are less adverse, the protein structure may be largely retained. Minor structural changes may induce an alternative active protein state with altered enzyme activity, specificity and stability.
p. 254-267
Received: 17 December 2009; in revised form: 12 January 2010 / Accepted: 15 January 2010 / Published: 20 January 2010
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| Download PDF Full-text (786 KB) | Download XML Full-text Abstract: Dye-sensitized solar cells (DSSCs) were assembled by using the bougainvillea flowers, red turnip and the purple wild Sicilian prickly pear fruit juice extracts as natural sensitizers of TiO2 films. The yellow orange indicaxanthin and the red purple betacyanins are the main components in the cocktail of natural dyes obtained from these natural products. The best overall solar energy conversion efficiency of 1.7% was obtained, under AM 1.5 irradiation, with the red turnip extract, that showed a remarkable current density (Jsc = 9.5 mA/cm2 ) and a high IPCE value (65% at λ = 470 nm). Also the purple extract of the wild Sicilian prickly pear fruit showed interesting performances, with a Jsc of 9.4 mA/cm2 , corresponding to a solar to electrical power conversion of 1.26%.
(This article belongs to the Special Issue
Solar Cells )
p. 268-287
Received: 13 November 2009; in revised form: 11 January 2010 / Accepted: 12 January 2010 / Published: 21 January 2010
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| Download PDF Full-text (236 KB) | Download XML Full-text Abstract: Microcystins (MC) are potent hepatotoxins produced by the cyanobacteria of the genera Planktothrix , Microcystis , Aphanizomenon , Nostoc and Anabaena . These cyclic heptapeptides have strong affinity to serine/threonine protein phosphatases (PPs) thereby acting as an inhibitor of this group of enzymes. Through this interaction a cascade of events responsible for the MC cytotoxic and genotoxic effects in animal cells may take place. Moreover MC induces oxidative stress in animal cells and together with the inhibition of PPs, this pathway is considered to be one of the main mechanisms of MC toxicity. In recent years new insights on the key enzymes involved in the signal-transduction and toxicity have been reported demonstrating the complexity of the interaction of these toxins with animal cells. Key proteins involved in MC up-take, biotransformation and excretion have been identified, demonstrating the ability of aquatic animals to metabolize and excrete the toxin. MC have shown to interact with the mitochondria. The consequences are the dysfunction of the organelle, induction of reactive oxygen species (ROS) and cell apoptosis. MC activity leads to the differential expression/activity of transcriptional factors and protein kinases involved in the pathways of cellular differentiation, proliferation and tumor promotion activity. This activity may result from the direct inhibition of the protein phosphatases PP1 and PP2A. This review aims to summarize the increasing data regarding the molecular mechanisms of MC toxicity in animal systems, reporting for direct MC interacting proteins and key enzymes in the process of toxicity biotransformation/excretion of these cyclic peptides.
p. 288-303
Received: 7 December 2009; in revised form: 10 January 2010 / Accepted: 17 January 2010 / Published: 21 January 2010
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| Download PDF Full-text (1457 KB) | Download XML Full-text Abstract: We report self-assembly and phase transition behavior of lower diamondoid molecules and their primary derivatives using molecular dynamics (MD) simulation and density functional theory (DFT) calculations. Two lower diamondoids (adamantane and diamantane), three adamantane derivatives (amantadine, memantine and rimantadine) and two artificial molecules (ADM•Na and DIM•Na) are studied separately in 125-molecule simulation systems. We performed DFT calculations to optimize their molecular geometries and obtained atomic electronic charges for the corresponding MD simulation, by which we predicted self-assembly structures and simulation trajectories for the seven different diamondoids and derivatives. Our radial distribution function and structure factor studies showed clear phase transitions and self-assemblies for the seven diamondoids and derivatives.
p. 304-311
Received: 3 December 2009; in revised form: 11 January 2010 / Accepted: 12 January 2010 / Published: 21 January 2010
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| Download PDF Full-text (322 KB) | Download XML Full-text Abstract: Single molecule techniques improve our understanding of the photon and light. If the single photon double slit experiment is performed at the “single photon limit” of a multi-atom light source, faint light pulses with more than one photon hamper the interpretation. Single molecules, quantum dots or defect centres in crystals should be used as light source. “Single photon detectors” do not meet their promise―only “photon number resolving single photon detectors” do so. Particularly, the accumulation time argument, the only safe basis for the postulate of a strictly particle like photon, has so far not yet been verified.
p. 312-328
Received: 23 December 2009 / Accepted: 15 January 2010 / Published: 21 January 2010
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| Download PDF Full-text (296 KB) | Download XML Full-text Abstract: Since biological membranes are composed of lipids and proteins we tested the in vitro antioxidant properties of several indoleamines from the tryptophan metabolic pathway in the pineal gland against oxidative damage to lipids and proteins of synaptosomes isolated from the rat brain. Free radicals were generated by incubation with 0.1 mM FeCl3 , and 0.1 mM ascorbic acid. Levels of malondialdehyde (MDA) plus 4-hydroxyalkenal (4-HDA), and carbonyl content in the proteins were measured as indices of oxidative damage to lipids and proteins, respectively. Pinoline was the most powerful antioxidant evaluated, with melatonin, N -acetylserotonin, 5-hydroxytryptophan, 5-methoxytryptamine, 5-methoxytryptophol, and tryptoline also acting as antioxidants.
p. 329-353
Received: 13 November 2009; in revised form: 23 December 2009 / Accepted: 17 January 2010 / Published: 22 January 2010
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| Download PDF Full-text (1324 KB) | Download XML Full-text Abstract: New organic dyes comprising carbazole, iminodibenzyl, or phenothiazine moieties, respectively, as the electron donors, and cyanoacetic acid or acrylic acid moieties as the electron acceptors/anchoring groups were synthesized and characterized. The influence of heteroatoms on carbazole, iminodibenzyl and phenothiazine donors, and cyano-substitution on the acid acceptor is evidenced by spectral, electrochemical, photovoltaic experiments, and density functional theory calculations. The phenothiazine dyes show solar-energy-to-electricity conversion efficiency (η ) of 3.46–5.53%, whereas carbazole andiminodibenzyl dyesshow η of 2.43% and 3.49%, respectively.
p. 354-369
Received: 24 December 2009; in revised form: 18 January 2010 / Accepted: 20 January 2010 / Published: 25 January 2010
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| Download PDF Full-text (130 KB) | Download XML Full-text Abstract: Bone adaptation or integration of an implant is characterized by a series of biological reactions that start with bone turnover at the interface (a process of localized necrosis), followed by rapid repair. The wound healing response is guided by a complex activation of macrophages leading to tissue turnover and new osteoblast differentiation on the implant surface. The complex role of implant surface topography and impact on healing response plays a role in biological criteria that can guide the design and development of future tissue-implant surface interfaces.
p. 370-385
Received: 13 November 2009; in revised form: 6 January 2010 / Accepted: 17 January 2010 / Published: 25 January 2010
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| Download PDF Full-text (266 KB) | Download XML Full-text Abstract: Genotype/phenotype association analyses (Treescan) with plasma lipid levels and functional site prediction methods (TreeSAAP and PolyPhen) were performed using sequence data for ANGPTL4 from 3,551 patients in the Dallas Heart Study. Biological assays of rare variants in phenotypic tails and results from a Treescan analysis were used as “known” variants to assess the site prediction abilities of PolyPhen and TreeSAAP. The E40K variant in European Americans and the R278Q variant in African Americans were significantly associated with multiple lipid phenotypes. Combining TreeSAAP and PolyPhen performed well to predict “known” functional variants while reducing noise from false positives.
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