Researcher:
Ulusoy, Gülen

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Gülen

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Ulusoy

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Ulusoy, Gülen

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2010 - 20154

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Researcher Of Publications: search.filters.isAuthorOfPublication.38e49b24-8f4e-46da-be10-429c71eb3f29

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    Pharmacogenetics of thiopurine methyltransferase in treatment of acute lymphoblastic leukemiawith 6-mercaptopurine in Turkish children-discordant cases
    (Wiley-Blackwell, 2013) Arınç, Emel; Tümer, Tuğba Boyuneğmez; Şahin, Gürses; Department of Chemistry; Ulusoy, Gülen; N/A; Department of Chemistry; College of Sciences; N/A
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    DNA repair XRCC1 Arg399Gln polymorphism alone, and in combination with CYP2E1 polymorphisms significantly contribute to the risk of development of childhood acute lymphoblastic leukemia
    (Pergamon-Elsevier Science Ltd, 2010) Tümer, Tuğba Boyuneğmez; Yılmaz, Duygu; Tanrıkut, Cihan; Şahin, Gürses; Arınç, Emel; Department of Chemistry; Ulusoy, Gülen; N/A; Department of Chemistry; College of Sciences; N/A
    It is now well established that genetic polymorphisms impairing the DNA repair capacity can disrupt the genomic integrity and potentially modulate individual's susceptibility to various cancers. In this study, we investigated the possible association of X-ray repair cross-complimenting group 1 (XRCC1) Arg399Gln and Arg194Trp variants with the risk of incidence of childhood acute lymphoblastic leukemia (ALL) in Turkish population comprised of 190 healthy controls and 167 ALL patients. For Arg399Gln polymorphism, the heterozygous (Arg/Gln) and homozygous mutant (Gln/Gln) genotypes were significantly more common in the ALL patients than the controls (OR: 1.6, p = 0.04). Particularly, the Gln399Gln genotype significantly increased the risk of disease up to 2.0-fold (OR: 2.0, p = 0.04). Besides, Gln399Gln genotype has been found to be associated with considerably increased risk of ALL among females (OR = 2.9, p = 0.03). In case of codon 194 polymorphism, no significant associations have been found with risk of childhood ALL. In addition, none of the combinations of XRCC1 codon 194 and 399 polymorphisms have been found to be significantly associated with childhood ALL risk. In the scope of this study, we have also showed that the co-presence of XRCC1 codon 399 and CYP2E1*5B and *6 polymorphisms (data for CYP2E1 polymorphisms drawn from previously published study conducted in our lab) in the same individuals considerably increased the risk for childhood ALL to 3.7-fold with borderline significance (p = 0.049). The observed combined effect was considerably more prominent among females (OR = 17.4, p = 0.001) and need to further investigation. This is the first study showing combined associations of XRCC1 399Gln, CYP2E1*5B and *6 alleles with the risk of development of childhood ALL.
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    Cyto/hemocompatible magnetic hybrid nanoparticles (ag2s-fe3o4) with luminescence in the near-infrared region as promising theranostic materials
    (Elsevier, 2015) Grandfils, Christian; Ojea-Jimenez, Isaac; Rossi, Francois; Dogan, Nurcan; Department of Physics; N/A; Department of Chemistry; Department of Chemistry; N/A; Kiraz, Alper; Hocaoğlu, İbrahim; Aşık, Didar; Acar, Havva Funda Yağcı; Ulusoy, Gülen; Faculty Member; PhD Student; Master Student; Faculty Member; N/A; Department of Physics; Department of Chemistry; College of Sciences; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Sciences; N/A; 22542; N/A; N/A; 178902; N/A
    Small hybrid nanoparticles composed of highly biocompatible Ag2S quantum dots (QD) emitting in the near-infrared region and superparamagnetic iron oxide (SPION) are produced in a simple extraction method utilizing ligand exchange mechanism. Hybrid nanoparticles luminesce at the same wavelength as the parent QD, therefore an array of hybrid nanoparticles with emission between 840 and 912 nm were easily produced. Such hybrid structures have (1) strong luminescence in the medical imaging window eliminating the autofluoresence of cells as effective optical probes, (2) strong magnetic response for magnetic targeting and (3) good cyto/hemocompatibility. An interesting size dependent cytotoxicity behavior was observed in HeLa and NIH/3T3 cell lines: smallest particles are internalized significantly more by both of the cell lines, yet showed almost no significant cytotoxicity in HeLa between 10 and 25 mu g/mL Ag concentration but were most toxic in NIH/3T3 cells. Cell internalization and hence the cytotoxicity enhanced when cells were incubated with the hybrid nanoparticles under magnetic field, especially with the hybrid nanoparticles containing larger amounts of SPION in the hybrid composition. These results prove them as effective optical imaging agents and magnetic delivery vehicles. Combined with the known advantages of SPIONs as a contrast agent in MRI, these particles are a step forward for new theranostics for multimode imaging and magnetic targeting.
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    PublicationOpen Access
    Meso-2,3-dimercaptosuccinic acid: from heavy metal chelation to CdS quantum dots
    (Royal Society of Chemistry (RSC), 2012) Özen, Can; N/A; Department of Chemistry; Sevinç, Esra; Ertan, Fatoş Sibel; Ulusoy, Gülen; Acar, Havva Funda Yağcı; Faculty Member; Department of Chemistry; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); Graduate School of Sciences and Engineering; College of Sciences; N/A; N/A; N/A; 178902
    DMSA (meso-2,3-dimercaptosuccinic acid) a prescription drug and a heavy-metal chelating agent, is shown to act both as a sulfur source and a capping agent in the aqueous synthesis of CdS quantum dots under mild conditions. Release of sulfur from DMSA depends on the solution pH and the reaction temperature. Combination of 70 C and pH 7.5 was determined as the best reaction conditions for a well-controlled reaction. Changing the SH/Cd ratio from 2.5 to 7 provides QDs emitting from blue to orange with 6–9% quantum yield with respect to Rhodamine 2B. Viability tests performed with HeLa and MCF-7 cell lines indicate a very low cytotoxicity. Mild reaction conditions and biocompatibility makes these particles valuable candidates for bio applications.