90 research outputs found
Cancer therapy and pharmacogenetic approach: Scientific letter
No full textAdverse drug reactions are important public health problem. Adverse drug reactions are an important public health problem. Inherited genetic variations in both host genome and the tumor genome affect drug response in cancer patients. Pro-drugs are metabolized through serial biochemical reactions (phase I, phase II etc.) by using detoxification enzymes. Functional polymorphisms in the genes encoding detoxification enzymes cause inter-individual differences, which contribute to adverse drug reactions as a result of standard chemotherapy protocols. Clinicians generally start the treatment with the average dose. The application of pharmacogenetic testing to cancer therapy is attractive because it helps to reduce the fatal adverse effect of therapeutics and creates effective individual medical strategies. Many cheap and fast molecular techniques are developed for pharmacogenetic screening. The most prominent two examples of pharmacogenetic tests used in oncology are the tests determining the toxicity of chemotherapeutics (5-fluorouracil, irinotecan, thiopurine etc.) and the tests determining the response to the treatment with specific molecular therapeutics (imatinib, rituximab and gefitinib etc.). Baseline pharmacogenetic testing before starting therapy is expected to be useful for the individualization and optimization of cancer chemotherapy. Recently high-throughput screening has been developed to identify the genes influencing polygenic drug response by using gene expression profiles
Production and characterization of electrospun fish sarcoplasmic protein based nanofibers
No full textŞahin, Yeşim Müge (Arel Author)In this study, poly (e-caprolactone) (PCL) and fish sarcoplasmic protein (FSP) (Mw < 200 kDa) composite nanofibers were fabricated by electrospinning technique. Solution properties such as density, viscosity, conductivity and surface tension were studied as a function of FSP content in the solution. The morphology, molecular interaction, degradation as well as thermal and tensile properties of PCL/FSP nanofibers were investigated. The results show that smooth and beadless PCL/FSP nanofibers with the diameters ranging from 120 +/- 29 nm to 139 +/- 41 nm were obtained. The average diameters decreased and the diameter distributions narrowed with the addition of optimum FSP amount. The characteristic picks of FSP and PCL were identified in the composite nanofibers by structural analyses. PCL/FSP nanofibers exhibited high degradation ability in comparison to electrospun pure PCL nancifibers. Moreover, the PCL/FSP nanofibers exhibit good mechanical properties (tensile strength of 5.55 MPa) with the additional FSP content. (C) 2017 Elsevier Ltd. All rights reserved
Synthesis, characterization, and biological properties of composites of hydroxyapatite and hexagonal boron nitride
No full textŞahin, Yeşim Müge (Arel Author)Hydroxyapatite (HA), obtained from bovine bones, was successfully reinforced with hexagonal boron nitrite (h-BN). h-BN/HA composites, with BN content up to 1.5 wt %, were sintered at various temperatures between 1000 and 1300 degrees C, in air. Well-sintered samples were obtained after sintering at 1200 and 1300 degrees C. The presence of h-BN contributed to dense, fine, and well-crystallized microstructure. The results of X-ray diffraction analysis and FT-IR spectroscopy showed that the produced composites comprised biphasic beta-TCP/HCA (HCA: carbonate partially substituted HA). High values of mechanical properties were achieved, namely compression strength 155 MPa for the sample 0.5% h-BN/HA and Vickers microhardness of 716 HV for the samples 1.5% h-BN/HA, both sintered at 1300 degrees C. U2OS human bone osteosarcoma proliferation and cell viability showed no adverse effect in the presence of h-BN/HA, suggesting the potential use of the produced materials as safe biomaterials in bone tissue engineering. (C) 2017 Wiley Periodicals, Inc
Allelotype frequencies of TPMT (thiopurine S-methyltransferase), CYP3A4 and CYP3A5 genes in Turkish population
No full text3D Printing Artificial Blood Vessel Constructs Using PCL/Chitosan/Hydrogel Biocomposites
No full textŞahin, Yeşim Müge (Arel Author)The present paper aims to overcome the problems related to previous use of autologous grafts using available synthetic grafts. To examine the optimum of the ideal vessel-like constructs parameters are produced at 230 degrees C. At this production temperature, the elastic modulus values of the constructs ranges from 56 MPa to 174 MPa. The maximum cell proliferation is obtained from PCL/7wt.%CS/5wt.%H that is tested by mitochondrial dehydrogenase activity. The structures are visualized with all constructs after cell fixation by making use of the HUVEC cell line
A simple chemical method for conversion of Turritella terebra sea snail into nanobioceramics
No full textŞahin, Yeşim Müge (Arel Author)In this study, a sea shell was converted into bioceramic phases at three different sintering temperatures (450 degrees C, 850 degrees C, 1000 degrees C). Among the obtained bioceramic phases, a valuable beta-TCP was produced via mechanochemical conversion method from sea snail Turritella terebra at 1000 degrees C sintering temperature. For this reason, only the bioceramic sintered at 1000 degrees C was concentrated on and FT-IR, SEM/EDX, BET, XRD, ICP-OES analyses were carried out for the complete characterization of beta-TCP phase. Biodegradation test in Tris-buffer solution, bioactivity tests in simulated body fluid (SBF) and cell studies were conducted. Bioactivity test results were promising and high rate of cell viability was observed in MTT assay after 24 hours and 7 days incubation. Results demonstrated that the produced beta-TCP bioceramic is qualified for further consideration and experimentation with its features of pore size and ability to support bone tissue growth and cell proliferation. This study suggests an easy, economic method of nanobioceramic production
Communication media use, social networks, and identity management by immigrant women entrepreneurs in an urban economy
No full textImmigrant women entrepreneurs are one of the disadvantaged communities in developed nations. Social change can be promoted in marginalized communities by analyzing how communication can transform the lives of people who are socially, politically and economically disadvantaged. In an attempt to promote social change, this study explored the communication strategies adopted in the situated experiences of immigrant women entrepreneurs as influenced by their gender, ethnic, religious and immigrant identities. Utilizing a mixed-method, 60 in-depth interviews and 100 survey questionnaires were conducted with immigrant women entrepreneurs from various ethnic and cultural backgrounds in an urban environment of New York City. This study revealed how various organizing practices including identity negotiation, place making, communication media use, (in)visibility and social networking help immigrant women entrepreneurs construct a desired entrepreneurial identity and thereby contribute to their empowerment and business sustainability and growth.Ph.D.Includes bibliographical referencesby Müge Hasek
Nanostructured biomaterials with antimicrobial properties
No full text#nofulltext# --- Şahin, Yeşim Müge (Arel Author)The present review is intended to bring together the main advances in the field of nanostructured biomaterials with antimicrobial properties. It is generally accepted that the discovery of antibiotics was of great importance but, nowadays new antimicrobial agents are needed and/or their better administration routes. The limitation of the use of antibiotics is essential because of the following reasons: the excessive use of antibiotics leads to the development of antibiotic resistant microorganisms; there are some alternatives for many types of infections, many of these alternatives being less toxic and do not lead to antibiotic similar resistance. In compliance with the above presented, the use of antibiotic is recommended to be eliminated (when alternatives are available) or to be reduced by using combined therapy when possible or to administrate these drugs through targeted or loco-regional drug delivery systems
Drug delivery systems for dental applications
No full text#nofulltext# --- Şahin, Yeşim Müge (Arel Author)Inevitable caries formation and other tooth related diseases are one of the most common factors affecting human quality of life, as they are often followed by loss of teeth. Significant research efforts have been devoted to establishing control and preventive solutions. It is clearly known that fluoride is one of the promising chemical substances with anti-carious activity. The elimination of the microbial infection, especially the multispecies infections induced by aerobic and anaerobic bacteria, is a current challenge of the endodontic therapy. Using antibiotics or other active agents (from ions, nanoparticles to natural products) loaded in specific drug carrier systems seems to be ideal approach in treating and controlling dental diseases, even if, the drug delivery systems used in dental applications are less established comparing with other tissues/organs. Based on the importance of biomedical drug delivery systems the present study aims to give a brief review on the improvements of drug delivery systems for dental applications
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