5,934 research outputs found
SH-SY5Y İnsan Hücre Hattı: Hawthorne Berry (Crataegus spp.) Parkinson Hastalığının İn Vitro Modelinde Oluşturulan 6-OHDA Kaynaklı Nörotoksisiteye Karşı Korur
No full textAim: We purposed to study the neuroprotective effects of Hawthorn berry (crataegus spp.) extract, which is familiar to have antioxidant and anti-inflammatory features, opposite the neurotoxicity led to by 6-OHDA in SH-SY5Y cells. Method: SH-SY5Y cells were treated with Hawthorn berry (25-50-75 and 100 ?g/mL) for two hours ago 6-OHDA administration. Cells were exposed to 200 µM 6-OHDA for 24 hours to mimic the in vitro Parkinson's disease model. After one day, cell viability was measured by lactate dehydrogenase and 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide analysis. Oxidative stress was evaluated with tumor necrosis factor-?, interleukin-1?, superoxide dismutase, catalase, glutathione, glutathione peroxidase, myeloperoxidase, and malondialdehyde assays. Results: It was found that the viability rate of Hawthorn berry increased depending on the concentration and the cell viability was 94% at the highest concentration (p<0.001). Also, 6-OHDA raised lactate dehydrogenase leakage in SH-SY5Y cells (p<0.001). While 6-OHDA exacerbated oxidative stress by enhancing tumor necrosis factor-?, interleukin-1?, myeloperoxidase, and malondialdehyde (p<0.001), pretreatment with Hawthorn berry alleviated these toxic effects of 6-OHDA through antioxidant capacity by increasing glutathione peroxidase, superoxide dismutase, catalase and glutathione (p<0.05), (p<0.001). In line with all findings, Hawthorn berry attenuated neuronal cell demise in a dose-dependent manner. Conclusion: Considering its neuroprotective role as well as its effects on oxidative stress, Hawthorn berry could be a potential natural bio-medicine to prevent the development of Parkinson's disease.Amaç: Çalışmada antioksidan ve antiinflamatuar özelliklere sahip olduğu bilinen Hawthorn berry (crataegus spp.) ekstraktın, SH-SY5Y hücrelerinde 6-OHDA ile meydana gelen nörotoksisiteye karşı nöroprotektif etkilerini araştırmayı amaçlanmıştır. Yöntem: SH-SY5Y hücreleri, 6-OHDA uygulamasından önce iki saat boyunca Hawthorn berry (25, 50, 75 ve 100 ?g/mL) ile muamele edildi. Hücreler, in vitro Parkinson hastalığı modelini taklit etmek için 24 saat boyunca 200 uM 6-OHDA’ya maruz bırakıldı. Bir gün sonra, 3-(4,5 Dimetiltiazol-2-il)-2,5-difeniltetrazolyum bromür ve laktat dehidrogenaz tahlilleri ile hücre canlılığı belirlendi. Oksidatif stres tümör nekroz faktör-?, interlökin-1?, süperoksit dismutaz, katalaz, glutatyon, glutatyon peroksidaz, miyeloperoksidaz ve malondialdehit analizleri ile değerlendirildi. Bulgular: Canlılık oranında Hawthorn berry’nin konsantrasyona bağlı olarak bir artış gösterdiği ve en yüksek konsantrasyonda hücre canlılığı % 94 oranında bulundu (p<0,001). Ayrıca, 6-OHDA SH-SY5Y hücrelerinde laktat dehidrogenaz sızıntısını arttırdı (p<0,001). 6-OHDA tümör nekroz faktör-?, interlökin-1?, miyeloperoksidaz ve malondialdehit artırarak oksidatif stresi şiddetlendirirken (p<0,001), Hawthorn berry ile ön tedavi süperoksit dismutaz, katalaz, glutatyon ve glutatyon peroksidazı artırarak antioksidan kapasite yoluyla 6-OHDA'nın bu toksik etkilerini hafifletti (p<0,05), (p<0,001). Tüm bulgular doğrultusunda Hawthorn berry nöronal hücre ölümünü hafifleterek doza bağlı bir şekilde önledi. Sonuç: Oksidatif stres üzerindeki etkilerinin yanı sıra nöroprotektif rolü göz önüne alındığında Hawthorn berry, Parkinson hastalığının gelişimini önlemek için potansiyel doğal biyo-ilaç olabilir
Neuroprotective effects of Vaccinium spp. berry pomace extracts in SHSY5Y cell model
No full textMūsdienās pieaug interese par Vaccinium spp. ogu izspiedām, kā par potenciālu veselībai nozīmīgu ar fitoķīmiskām vielām bagātu avotu. Neirodeģenerācija ir patoloģisku procesu kopums, kas izraisa neironu nāvi, tāpēc tā novēršanai tiek meklēti neiroprotektīvi savienojumi. Darba mērķis ir pētīt piecu Vaccinium spp. ogu izspiedu ekstraktu acetilholīnesterāzes inhibīciju bezšūnu un SH-SY5Y šūnu modeļos un šūnu izdzīvošanas stimulāciju ar terciālā butilhidroksiperoksīda izraisītā oksidatīvā stresa apstākļos. Visi ogu ekstrakti inhibēja acetilholīnesterāzes aktivitāti, kā arī uzlaboja SH-SY5Y šūnu dzīvotspēju oksidatīvā stresa modelī. Augstāka acetilholīnesterāzes inhibīcija bija novērojama SH-SY5Y šūnu modelī. Secinājām, ka Vaccinium spp. ogu izspiedu ekstraktiem ir neiroprotektīvas īpašības in vitro.Today there is a growing interest in Vaccinium spp. berry pomace as potential source of phytochemicals that are important for health. Neurodegeneration is a set of pathological processes that cause neuronal death, therefore neuroprotective compounds are being searched. The aim of this study was to investigate the five Vaccinium spp. berry pomace extracts acetylcholinesterase inhibition potency in cell-free and SH-SY5Y cell models and cell survival stimulation effects under oxidative stress induced by tertiary butylhydroxyperoxide. All berry extracts inhibited acetylcholinesterase activity as well as improved SH-SY5Y cell viability in an oxidative stress model. Higher acetylcholinesterase inhibition was observed in the SH-SY5Y cell model. We concluded that Vaccinium spp. berry extract extracts have neuroprotective properties in vitro
Cellular Stress and p53-Associated Apoptosis by Juniperus communis L. Berry Extract Treatment in the Human SH-SY5Y Neuroblastoma Cells
No full textPlant phenolics have shown to activate apoptotic cell death in different tumourigenic cell lines. In this study, we evaluated the effects of juniper berry extract (Juniperus communis L.) on p53 protein, gene expression and DNA fragmentation in human neuroblastoma SH-SY5Y cells. In addition, we analyzed the phenolic composition of the extract. We found that juniper berry extract activated cellular relocalization of p53 and DNA fragmentation-dependent cell death. Differentially expressed genes between treated and non-treated cells were evaluated with the cDNA-RDA (representational difference analysis) method at the early time point of apoptotic process when p53 started to be activated and no caspase activity was detected. Twenty one overexpressed genes related to cellular stress, protein synthesis, cell survival and death were detected. Interestingly, they included endoplasmic reticulum (ER) stress inducer and sensor HSPA5 and other ER stress-related genes CALM2 and YKT6 indicating that ER stress response was involved in juniper berry extract mediated cell death. In composition analysis, we identified and quantified low concentrations of fifteen phenolic compounds. The main groups of them were flavones, flavonols, phenolic acids, flavanol and biflavonoid including glycosides of quercetin, apigenin, isoscutellarein and hypolaetin. It is suggested that juniper berry extract induced the p53-associated apoptosis through the potentiation and synergism by several phenolic compounds.Peer reviewe
Layers of Blackness: Colourism in the African Diaspora
No full textThis is the first book by an author in the UK to take an in-depth look at colourism - the process of discrimination based on skin tone among members of the same ethnic group, whereby lighter skin is more valued than darker complexions. The African Diaspora in Britain is examined as part of a global black community with shared experiences of slavery, colonization and neo-colonialism. The author traces the evolution of colourism within African descendant communities in the USA, Jamaica, Latin America and the UK from a historical and political perspective and examines its present impact on the global African Diaspora. This book is essential reading for educators and students and will appeal to anyone with an interest in the subject of race and identity who wants to understand why colourism - a psychological legacy of slavery still impacts people of African descent in the Diaspora today
Quantum anomalous Hall and quantum spin-Hall phases in flattened Bi and Sb bilayers
No full textDiscovery of two-dimensional topological insulator such as Bi bilayer initiates challenges in exploring exotic quantum states in low dimensions. We demonstrate a promising way to realize the Kane-Mele-type quantum spin Hall (QSH) phase and the quantum anomalous Hall (QAH) phase in chemically-modified Bi and Sb bilayers using first-principles calculations. We show that single Bi and Sb bilayers exhibit topological phase transitions from the band-inverted QSH phase or the normal insulator phase to Kane-Mele-type QSH phase upon chemical functionalization. We also predict that the QAH effect can be induced in Bi or Sb bilayers upon nitrogen deposition as checked from calculated Berry curvature and the Chern number. We explicitly demonstrate the spin-chiral edge states to appear in nitrogenated Bi-bilayer nanoribbons.open1139sciescopu
Berry-Esséen bound for high dimensional asymptotic approximation of Wilks' Lambda distribution
No full textLet [Lambda]=Se/Se+Sh, where Sh and Se are independently distributed as Wishart distributions Wp(q,[Sigma]) and Wp(n,[Sigma]), respectively. Then [Lambda] is distributed as Wilks' lambda distribution [Lambda]p,q,n which appears as the distributions of various multivariate likelihood ratio tests. In this paper, we derive a Berry-Essen bound for a high dimensional asymptotic approximation of the distribution of when p/n-->c[set membership, variant](0,1).Asymptotic distribution Berry-Esséen bound High dimensional approximation Wilks' lambda distribution
Wellesly Sh. W. to Mr. James Meredith (2 October 1962)
No full textSigned by Wellesly Sh. W.https://egrove.olemiss.edu/mercorr_pro/1531/thumbnail.jp
SMA-SH: Modified styrene maleic acid copolymer for functionalization of lipid nanodiscs
No full textChallenges in purification and subsequent functionalization of membrane proteins often complicate their biochemical and biophysical characterization. Purification of membrane proteins generally involves replacing the lipids surrounding the protein with detergent molecules, which can affect protein structure and function. Recently, it was shown that styrene–maleic acid copolymers (SMA) can dissolve integral membrane proteins from biological membranes into nanosized discs. Within these nanoparticles, proteins are embedded in a patch of their native lipid bilayer that is stabilized in solution by the amphipathic polymer that wraps the disc like a bracelet. This approach for detergent-free purification of membrane proteins has the potential to greatly simplify purification but does not facilitate conjugation of functional compounds to the membrane proteins. Often, such functionalization involves laborious preparation of protein variants and optimization of labeling procedures to ensure only minimal perturbation of the protein. Here, we present a strategy that circumvents several of these complications through modifying SMA by grafting the polymer with cysteamine. The reaction results in SMA that has solvent-exposed sulfhydrils (SMA-SH) and allows tuning of the coverage with SH groups. Size exclusion chromatography, dynamic light scattering, and transmission electron microscopy demonstrate that SMA-SH dissolves lipid bilayer membranes into lipid nanodiscs, just like SMA. In addition, we demonstrate that, just like SMA, SMA-SH solubilizes proteoliposomes into protein-loaded nanodiscs. We covalently modify SMA-SH-lipid nanodiscs using thiol-reactive derivatives of Alexa Fluor 488 and biotin. Thus, SMA-SH promises to simultaneously tackle challenges in purification and functionalization of membrane proteins.BN/Marie-Eve Aubin-Tam LabBN/Andreas Engel La
Valley-symmetry-preserved transport in ballistic graphene with gate-defined carrier guiding
No full textEver since the discovery of graphene(1), valley symmetry and its control(2,3) in the material have been a focus of continued studies in relation to valleytronics(4,5). Carrier-guiding quasi-one-dimensional (1D) graphene nanoribbons (GNRs)(6-12) with quantized energy subbands preserving the intrinsic Dirac nature have provided an ideal system to that end. Here, by guiding carriers through dual-gate operation in high-mobility monolayer graphene, we report the realization of quantized conductance in steps of 4e(2)/h in zero magnetic field, which arises from the full symmetry conservation of quasi-1D ballistic GNRs with effective zigzag-edge conduction. A tight-binding model calculation confirms conductance quantization corresponding to zigzag-edge conduction even for arbitrary GNR orientation. Valley-symmetry conservation is further confirmed by intrinsic conductance interference with a preserved Berry phase of pi in a graphene-based Aharonov-Bohm(AB) ring preparedby similar dualgating. This top-down approach for gate-defined carrier guiding in ballistic graphene is of particular relevance in the efforts towards efficient and promising valleytronic applications.112013sciescopu
Omega-3 fatty acid eicospentaenoic acid attenuates MPP+-induced neurodegeneration in fully differentiated human SH- SY5Y and primary mesencephalic cells
No full textEicosapentaenoic acid ( EPA), a neuroactive omega-3 fatty acid, has been demonstrated to exert neuroprotective effects in experimental models of Parkinson's disease ( PD), but the cellular mechanisms of protection are unknown. Here, we studied the effects of EPA in fully differentiated human SH-SY5Y cells and primary mesencephalic neurons treated with MPP+. In both in-vitro models of PD, EPA attenuated an MPP+-induced reduction in cell viability. EPA also prevented the presence of electron-dense cytoplasmic inclusions in SH-SY5Y cells. Then, possible mechanisms of the neuroprotection were studied. In primary neurons, EPA attenuated an MPP+-induced increase in Tyrosine-related kinase B (TrkB) receptors. In SH-SY5Y cells, EPA down-regulated reactive oxygen species and nitric oxide. This antioxidant effect of EPA may have been mediated by its inhibition of neuronal NADPH oxidase and cyclo-oxygenase-2 ( COX-2), as MPP+ increased the expression of these enzymes. Furthermore, EPA prevented an increase in cytosolic phospholipase A2 ( cPLA2), an enzyme linked with COX-2 in the potentially pro-inflammatory arachidonic acid cascade. Lastly, EPA attenuated an increase in the bax:bcl-2 ratio, and cytochrome c release. However, EPA did not prevent mitochondrial enlargement or a decrease in mitochondrial membrane potential. This study demonstrated cellular mechanisms by which EPA provided neuroprotective effects in experimental P
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