529 research outputs found

    Cancer cell expulsion of anticancer drugs through shedding of microvesicles: association with drug resistance and tumour survival

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    Microvesicles (MVs) are small (0.1-≀1 ”m in diameter) heterogeneous vesicles released from cells constitutively or upon activation, that mediate intercellular communication. Multi-drug resistance (MDR) has been defined as the ability of cancer cells to survive after treatment with various drugs. However, the mechanism(s) used by cancer cells to evade apoptosis induced by anticancer drugs remain unclear and was the subject of our investigation. Here we report a novel mechanism of cancer cell expulsion of anticancer drugs through the release of MVs, followed by the recruitment of lysosomes to the site of release to repair the resulting damage. In addition, we show for the first time that inhibition of MV release by pretreatment of PC3M cells with the calpain inhibitor, calpeptin, sensitizes cancer cells to drug-elicited apoptosis mediated by the addition of methotrexate (MTX) and docetoxel (DOC) using at least 10-fold lower concentrations, both in vitro and in vivo. Treatment of cancer patients with MET or DOC leads to significant side effects due to the use of higher doses. Here we show that these drugs when administered together with calpeptin can be given at doses 100 times lower and still induce effective killing of target cancer cells. Overall our studies shed light on the role of MV release in cancer cell expulsion of anticancer drugs and subsequent evasion and survival from apoptosis and suggest new combination therapies for existing cancer drugs.Peer reviewedFinal Accepted Versio

    Coxsackie virus entry and spread in HeLa cells is aided by microvesicle release

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    Microvesicles(MVs) released from plasma membrane expressing surface phosphatidylserine and ranging from 0.2-≀1 m in diameter are reported to carry various membrane proteins, lipids and cytoplasmic components characteristic of the parental cell (1). Coxsackievirus B (CVB), a member of the enterovirus family is the main cause of meningitis and encephalitis in infants which may result in neurodevelopmental defects. Calpains are calcium-dependant cysteine proteases that degrade cytoplasmic and cytoskeletal proteins. They regulate a variety of actin-dependant cellular processes such as microvesiculation. CVB1 requires calpain activation for both entry and virus replication. Here, we show that knocking down calpain, using approaches such as small interfering RNA (siRNA), culminates in reduction of MV release, as we showed before with another intracellular pathogen, the protozoan parasite, Trypanosoma cruzi (2). The reduction in MV release then abrogates CVB1 entry and spread in HeLa cells. The calpain inhibitor calpeptin also caused similar reduction in CVB1 entry and spread to healthy target cells. Together, our findings provide evidence that CVB1 infected HeLa cells enhance MV production, and these MVs aid the spread of infection. Furthermore, inhibition of MV release using siRNA results in inhibition of CVB1 entry and spread.Peer reviewedFinal Accepted Versio

    Physiologically responsive mechanically adaptive polymeric materials for biomedical applications

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    KĂŒnstliche neurale Schnittstellen können verwendet werden, um das zentrale Nervensystem mit der Ă€usseren Welt zu verbinden. Sie bieten deshalb grosses Potential fĂŒr die Rehabilitierung von Patienten, die unter LĂ€hmung, anderen Formen von motorischer Dysfunktion oder Amputationen leiden. Es wurden verschiedene Arten neuraler Gehirnschnittstellen entwickelt, mit unterschiedlichen InvasivitĂ€tsgraden sowie der FĂ€higkeit, neurale Signale aufzunehmen. Beispielsweise können nicht-eindringende aufzeichnende Elektroden, welche extern auf der Kopfhaut oder subdural auf der HirnoberflĂ€che angebracht werden, funktionale Informationen gewinnen. Allerdings ist unter Forschern die Annahme verbreitet, dass Aufzeichnungs- und StimulationsgerĂ€te, die in spezifische Regionen des Gehirns eindringen (z. B. intrakortikale Mikroelektroden), wahrscheinlich die nĂŒtzlichsten Signale einer neuralen Schnittstelle liefern werden. Trotz des Potentials, welches intrakortikale Mikroelektroden gezeigt haben, ist die breite klinische Implementation durch die Tatsache behindert, dass es schwierig ist, bestĂ€ndig qualitativ hochwertige neurale Signale ĂŒber einen klinisch relevanten Zeitrahmen aufzuzeichnen. Dies wird hauptsĂ€chlich durch Neuroinflammation verursacht, was sowohl Neuronendegeneration als auch Fremdkörperverkapselung beinhaltet. Viele Faktoren werden in Zusammenhang gebracht, einen Beitrag zur EntzĂŒndung der Gehirnareale in Folge von GerĂ€teimplantationen zu leisten, darunter die mechanische Diskrepanz zwischen dem hĂ€ufig sehr steifen Implantat und dem deutlich weicheren Hirngewebe, sowie dem oxidativen Stresszustand, der um das Implantat als Resultat der EntzĂŒndung entsteht. Um langzeit-bestĂ€ndige neurale Aufzeichnungen zu ermöglichen, werden neue Materialien fĂŒr die nĂ€chste Generation intrakortikaler Mikroelektroden benötigt, mit grösserer Betonung auf einer Reduktion der neuroinflammatorischen Antwort benötigt. Die vorliegende Dissertation verfolgt die Entwicklung physiologisch responsiver, mechanisch adaptiver Polymere fĂŒr neurale Schnittstellenapplikationen sowie eine Studie zur Struktur-Eigenschaftsbeziehung dieser Materialien. Ausgehend von einem zuvor etablierten Designprinzip fĂŒr chemisch-responsive mechanisch adaptive Materialien, inspiriert durch die Architektur der Dermis von Seegurken, wurden verschiedene Familien von Nanokompositen entworfen, prĂ€pariert und untersucht. Diese Materialien beinhalten ein Matrixpolymer, welches durch steife Cellulose Nanokristalle (cellulose nanocrystalls, CNCs) und die Wechselwirkungen zwischen den CNCs verstĂ€rkt wird, so dass auch die gesamten mechanischen Eigenschaften durch Kontakt mit Wasser beeinflusst werden können. Die adaptive Natur dieses Materials lĂ€sst es nĂŒtzlich erscheinen als Basis fĂŒr eindringende kortikale Mikroelektroden, die ausreichend steif sind, um einfach in den Kortex implantiert werden zu können, aber unter physiologischen Bedingungen erweichen und besser zur Steifigkeit des Gehirns passen. Mehrere neue, rational entworfene Materialien wurden untersucht. Nanokomposite basierend auf Polyvinylalkohol (PVA) und CNCs, gewonnen aus Manteltieren und Baumwolle, wurden hinsichtlich des Einflusses von AspektverhĂ€ltnis, OberflĂ€chenladungsdichte und FĂŒllstoffkonzentration auf die mechanischen Eigenschaften untersucht. Die neuen Materialien bieten eine anfĂ€ngliche Steifigkeit, welche signifikant höher ist als bei vorangegangenen Generationen solcher responsiver Materialien, vermutlich wegen der Wechselwirkungen zwischen Polymer und CNCs. Ferner wurde gezeigt, dass die Quellcharakteristika der Nanokomposite im wĂ€ssrigen Medium durch die Verarbeitungsbedingungen kontrolliert werden konnten. Unter Verwendung dieses Instruments konnte der „Schaltkontrast“ der Nanokomposite durch Kontakt mit (emulierten) physiologischen Bedingungen variiert werden. Physiologisch responsive mechanisch adaptive Materialien basierend auf Polyvinylalkohol oder Polyvinylacetat und CNCs, die aus Manteltieren oder Baumwolle gewonnen wurden, wurden so konzipiert, auch lokal die antioxidativen Wirkstoffe Curcumin, Resveratrol oder Superoxiddismutase mimetisch mit plötzlichen („burst“) oder nachhaltigen Freisetzungsprofilen zu regulieren. Diese Materialien reprĂ€sentieren die ersten Beispiele fĂŒr interkortikale Implantate, welche zwei voneinander unabhĂ€ngig effektive Mechanismen kombinieren – mechanische Verformbarkeit und lokale Freisetzung von Antioxidantien. Sie erlauben erstmals Untersuchungen darĂŒber, wie die Freisetzungskinetik bei Antioxidanstherapie an der intrakortikalen Implantat-Gewebe GrenzflĂ€che die neurale Integration beeinflusst. Eine erste in-vivo Studie mit PVA/CNC/Curcumin Nanokompositen an Ratten zeigte, dass ĂŒber die ersten vier Wochen der Implantation Curcumin-freisetzende, mechanisch adaptive Implantate mit einer höheren NeuronenĂŒberlebensrate und einer stabileren Blut-Hirn-Schranke an der GrenzflĂ€che zwischen Implantat und Gewebe assoziiert wurden als die reinen Polyvinylalkohol Kontrollproben. Abschliessend wurde die FĂ€higkeit der mechanischen Verformung durch Einfluss physiologischer Bedingungen fĂŒr optische Fasern fĂŒr die Optogenetik verwendet. Diese kĂŒrzlich entwickelte Plattform fĂŒr neurale Schnittstellen beruht auf der Aktivierung oder Stummschaltung von Neuronen, die Licht verwenden. Es wird erwartet, dass die mechanische Diskrepanz zwischen konventionellen optischen Fasern und kortikalem Gewebe auch zur chronischen neuroinflammatorischen Antwort beitrĂ€gt. Daher wurden mechanisch adaptive optische Fasern aus PVA entwickelt, welche dieses Problem lindern könnten. Die Fasern wurden in einem einstufigen „dry-jet“ Nassspinnprozess produziert und sie zeigen eine anfĂ€ngliche Steifigkeit, die geringfĂŒgig höher ist als die kommerziell erhĂ€ltlicher optischer Fasern, und die mĂŒheloses EinfĂŒhren von Implantaten mit geringem Durchmesser in den Kortex ermöglicht. Unter (emulierten) physiologischen Bedingungen quellen die Fasern mit Wasser geringfĂŒgig auf und ihre Steifigkeit wird signifikant reduziert, wĂ€hrend die begleitenden VerĂ€nderungen der optischen Eigenschaften der Faser gering sind. Die optischen Fasern aus PVA erlauben es, Licht in einem WellenlĂ€ngenbereich zu transportieren, der hinreichend intensiv ist, Neuronen im Gehirn zu stimulieren und optischen Anforderungen fĂŒr optogenetische Anwendungen gerecht zu werden. Die vorliegende Dissertation leitet fundamentale Einblicke in Struktur- Eigenschaftsbeziehungen her, indem sie die adaptive Natur dieser Materialien durch Zusammensetzung (z.B. unterschiedliche Polymermatrices, Art und Menge der NanofĂŒller und therapeutischer Substanzen) sowie die Verarbeitungsbedingungen vertieft. WĂ€hrend in-vivo Studien zum hier vorliegenden neuen Material gerade erst begonnen haben, ist es schon heute ersichtlich, dass die im Rahmen dieser Dissertation hergestellten und untersuchten Materialien zum Fortschritt des VerstĂ€ndnisses nĂŒtzlich sind, wie stimuli-responsive Polymere helfen können, neuroinflammatorische Effekte in Zusammenhang mit Intrakortikalimplantaten zu verringern

    A Sociocultural Perspective on Everyday Interactions Stressing Grammatical vs. Communicative Competence: The Case of Iranian Taxi-discussions

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    Conversation analysis as a branch of the vast field of discourse studies, aims to show the structure and the process of social interaction between people in any genre of conversation. This aim is traced in this study as well. This study focuses on Dell Hymes’ idea on the notion of communicative competence which is going beyond the structural linguistic properties of language. The purpose of this study is to make a link between communicative competence and sociocultural dimensions of language, which has a determining role in building up interlocutors’ shared ground and enabling a course of communication to take place. For this purpose, a case of Iranian taxi discussions is selected. The conversational codes are identified and the reason why a specific code occurred is provided according to the contexts of that taxi discussion (the context is provided by the narrator’s detailed description of the detail about that situation and condition). This was a discussion that interlocutors opposed each others’ ideas; therefore, the most frequent code was FTA which occurred 6 times

    Refit to numerically problematic UMIST reaction rate coefficients

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    Aims. Chemical databases such as the UMIST Database for Astrochemistry (UDFA) are indispensable in the numerical modeling of astrochemical networks. Several of the listed reactions in the UDFA have properties that are problematic in numerical computations: Some are parametrized in a way that leads to extremely divergent behavior for low kinetic temperatures. Other reactions possess multiple entries that are each valid in a different temperature regime, but have no smooth transition when switching from one to another. Numerically, this introduces many difficulties.We present corrected parametrizations for these sets of reactions in the UDFA06 database. Methods. From the tabulated parametrization in UDFA, we created artificial data points and used a Levenberg-Marquardt algorithm to find a set of improved fit parameters without divergent behavior for low temperatures. For reactions with multiple entries in the database that each possess a different temperature regime, we present one joint parametrization that is designed to be valid over the whole cumulative temperature range of all individual reactions. Results. We show that it is possible to parametrize numerically problematic reactions from UDFA in a form that avoids low temperature divergence. Additionally, we demonstrate that it is possible to give a collective parametrization for reaction rate coefficients of reactions with multiple entries in UDFA. We present these new fitted values in tabulated form.Comment: accepted by A&

    Data ongreenhousegasesemission in condensateseparationunitofapetrochemical companyinIran

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    Sinceglobalwarmingduetogreenhousegasemissionsisno respecterofgeographicalboundariesofcountries,concerted mitigation activitiessuchas CleanDevelopmentMechanism (CDM), aresuitable.Inthis mechanism,somedeveloped countriescangaincertified emissionreductioncreditsfrom emission reductionactionsundertakenindevelopingcoun- tries.Thus,thedataofgreenhousegasemissionsindeveloping countrieswouldbeinformativeforimplementingofCDM. Herein,thedataofgreenhousegasemissionsofBandarImam PetrochemicalComplex,oneof the biggestpetrochemical companiesintheMiddleEastregionispresented.Thedatawas acquiredusingemissionfactormethodandself-presentedraw information oftheBandarImamPetrochemicalComplex. Overall,thedatawillbeinterestingforenvironmentalists,non- governmentalorganization(NGO), anddevelopedcountriesto perform CDM. & 2016TheAuthors.PublishedbyElsevierInc.Thisisanop

    Bioremediation of phenanthrene-polluted soil using Bacillus kochii AHV-KH14 as a halo-tolerant strain isolated from compost

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    Background: Phenanthrene (PHE) is a polycyclic aromatic hydrocarbon (PAH) with crystalline structure of C14H10, which was produced from incomplete combustion of hydrocarbons and fossil fuels and can cause harmful biological effects. Bioremediation using halophilic bacteria is payed attention over chemical methods due to considerable benefits. Methods: In the present study, a halo-tolerant bacterium Bacillus kochii strain AHV-KH14 was isolated from municipal compost, and used for the bioremediation of PHE from the contaminated soil. The effects of operational parameters including soil/water ratio, initial inoculum size, PHE concentration, and salinity on the bioremediation performance were investigated. Results: A biodegradation efficiency of about to 98% was obtained for PHE concentration of 50 mg/ kg and salinity level of 1.5%. By increasing salinity content PHE concentration, PHE biodegradation rate decreased significantly. It was found that the bioremediation efficiency decreased with increasing PHE concentration. It was also revealed that for the unwashed soil sample, cumulative concentrations of different hydrocarbons played an important role in decreasing the efficiency of bioremediation. Conclusion: A natural hydrocarbon-contaminated soil sample with total petroleum hydrocarbon (TPH) concentration of 2350 mg/kg was subjected to bioremediation using the selected conditions of operational parameters, and a biodegradation rate of 17.7% was obtained. Keywords: Biodegradation, Soil pollution, Phenanthrene, Bacillus kochii strain AHV-KH14, Compos

    An Efficient Biosurfactant by Pseudomonas stutzeri Z12 Isolated from an Extreme Environment for Remediation of Soil Contaminated with Hydrocarbons

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    Capability of a biosurfactant produced by Pseudomonas stutzeri Z12 for the removal of hydrocarbons from oily sludge contaminated soil was investigated. The effect of operating parameters, including pH, critical micelle concentration (CMC), salinity, and contact time were studied. The chemical structure of produced biosurfactant was characterized using FTIR and LC-MS-MS analysis, which revealed that the extracted biosurfactant was a combination of both mono- and di-rhamnolipid congeners. The main three congeners RhaC12:1C10 (529.9 m z–1), RhaC12C10 (531 m z–1), and RhaC10C10 (503.2 m z–1) were associated to mono-rhamnolipid, while five congeners, RhaRhaC10C8 (621.2 m z–1), RhaRhaC12C12 (707.7), RhaRhaC10C12 (677.1), RhaRhaC10C12:1 (675.3 m z–1), and RhaRhaC10C1 (649.5 m z–1) were associated to di-rhamnolipid structures. The critical micelle concentration (CMC) was 80 mg L–1, and emulsification index (E24) values for n-hexadecane, n-hexane, kerosene, diesel oil, xylene, and crude oil were 62.1, 57.6, 54.4, 41.5, 46.9, and 30.2 %, respectively. This work is licensed under a Creative Commons Attribution 4.0 International License

    REVIEWING THE EFFECTS OF TECHNOLOGY MANAGEMENT ON INNOVATION IN AHVAZ JUNDISHAPUR UNIVERSITY OF MEDICAL SCIENCES, IRAN

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    Technology management (management of technology or MOT) requires an extensive spectrum of capabilities in operational environments ranging from research and development to financial affairs (services) marketing and every other traditional management activity. Technological management needs to have an interdisciplinary approach and therefore requires a collection of different disciplines. While traditional management disciplines are pursuing how to allocate resources, technological management is not forced to allocate resources. In fact, it aims to further access and dominate the formation of the effects of technological variables on a business. Our country is classified among developing countries and technology transfer is recommended as a shortcut for access to state-of-the-art technologies, providing that technology transfer actually happens and Indigenization of transferred technologies to be considered. The present study examines the effects of technology on innovation in Ahvaz Jundishapur University of Medical Sciences. It is performed based on a descriptive study. For this purpose, four hypotheses have been raised in the study and the data required for this research were collected from 298 employees and managers from the university. The most important result of the present research is that the deployment of technology management and R&D (research and development) will lead to the promotion of quality functions and more importantly consolidation of innovation functions in the university of medical sciences. The value of Cronbach’s alpha for these 24 elements is equal to 0.935 which represented that the data have reliability (are reliable). In conclusion, the Pearson correlation coefficient test was used to confirm or reject the research hypotheses.JEL: O14, M54, O32 Article visualizations
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