Browsing by Author "Gümüs, A"

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    The glycosylation status of murin postnatal thymus
    Balcan, E; Gümüs, A; Sahin, M
    During the intrathymic development, the fate of the thymocytes depends largely on variable expression of CD4/CD8 markers and T cell receptor protein expressions. In addition, changes of cell surface glycosylation status also affect the thymocyte maturation. In this study the glycosylation alterations in thymic tissues from 1, 9, 13 and 16 days old mice were evaluated by histochemical and lectin blotting techniques. With alcian blue (AB) at pH 5.7/periodic acid-Schiff (PAS) stainings, it was shown that thymic microenvironments contained carboxlylated and sulfated glycosaminoglycans (GAGs). Strong positivity to AB at pH 2.5, which specific for sialomucins, was seen in some medullary thymocytes. Similarly, it was shown that with Maackia amurensis agglutinin (MAL) medullary thymocytes, but not cortical ones, contained alpha(2 -> 3) linked sialic acid structures. On the other hand, while reaction with peanut agglutinin (PNA), which specific for core disaccharide galactose beta(1 -> 3) N-acetylgalactosamine, was only seen in cortical thymocytes, reaction with Galanthus nivalis agglutinin (GNA), which specific for terminal mannose residues, was seen in both cortex and medulla. However, Datura stramonium agglutinin (DSA), which recognizes galactose beta(1 -> 4) N-acetylglucosamine, was not only cell-specific, but it was bound some thymic vessels. With lectin blotting studies, five glycoprotein bands of molecular weights similar to 39, similar to 54, 100, similar to 110 and similar to 212 were found which reacted with MAL, PNA and DSA as well as GNA. These results suggest that glycosylation patterns of cell surface glycoconjugates are modified during thymocyte selection processes of postnatal days.
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    The Effect of Tunicamycin on Embryonic and Newborn Murine Spleen Tissues
    Balcan, E; Arslan, Ö; Gümüs, A; Sahin, M
    Tunicamycin is an antibiotic that widely used in cell biology for its ability to inhibit N-linked glycosylation of asparagine residues on proteins and to induce endoplasmic reticulum stress. In the present study, the effects of tunicamycin on murine splenic tissues at 17th embryonic day and 1st and 3rd postnatal days were evaluated with three structural and physiological parameters: 1) alterations in glycosaminoglycan molecules, 2) apoptosis and 3) alterations in laminin molecules. It was shown that splenic microenvironments of control groups contain carboxylated glycosaminoglycans, but their content slightly decreased in all tunicamycin treated groups by alcian blue-periodic acid-Schiff method. On the other hand, there was an increase in the interstitial space among the cells of tunicamycin treated groups. In addition, it was shown by immunoblotting analyses that expression levels of laminin molecules were decreased by tunicamycin tratment in developing spleen tissues. In order to determine apoptotic effects of tunicamycin, TUNEL assay was performed and it was found that the number of apoptotic cells in developing spleen was strongly increased with tunicamycin treatments. These results suggest that, during the spleen development, the alterations of glycosaminoglycan contents in the extracellular matrix and the glycosylation status of extracellular glycoproteins (e. g. laminins) that mediate cell-extracellular matrix interactions are very important factors that seal the fate of cell physiology and morphogenesis.
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    An important source of preanalytical error in medical laboratories: centrifugation
    Sonmez, C; Gümüs, A; Senes, M; Aykal, G; Taneli, F; Aksungar, F; Avci, E; Coskun, C; Cinaroglu, I; Colak, A; Eker, P; Güçel, F; Hakligor, A; Inal, BB; Orhan, B; Yilmaz, C
    Centrifugation separates particles within the specimen according to their shape, dimensions, and density and basically can be defined as a separation method. The centrifuge is an essential device in medical laboratories to prepare the serum, plasma, and urine samples for analysis. It is basically an electric device composed of the stationary (motor) and the motile (rotor) part. The centrifugation depends on two main variables: relative centrifugal force (RCF) and centrifugation time. The physical impact separating the specimen into its components in the centrifuge known as RCF is expressed as the multiples of gravitational acceleration (xg). RPM, defined as the number of rotations of the centrifuge perminute, shows the speed of the centrifuge. RCF value can be calculated by using RPM, and the centrifuge radius. Because models and sizes of centrifuges vary considerably, the use of gravity (g) forces instead of RPM is suggested. The centrifuges can be classified according to their usage, speed, technical specifications, and rotor type. An accurate and precise centrifugation process is essential to prevent errors in the preanalytical phase. The purpose of this document is to ensure the standardization of a good, precise protocol for the centrifugation process among the medical laboratories.
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    Surface chemistry dependent toxicity of inorganic nanostructure glycoconjugates on bacterial cells and cancer cell lines
    Sancak, S; Yazgan, I; Bayarslan, AU; Ayna, A; Evecen, S; Tasdelen, Z; Gümüs, A; Sönmez, HA; Demir, MA; Demir, S; Bakar, F; Dilek-Tepe, H; Kasemets, K; Otsus, M; Çeter, T
    Surface functionalized nanostructures have outstanding potential in biological applications owing to their target -specific design. In this study, we utilized laboratory synthesized carbohydrate-derivatives (i.e., galactose, mannose, lactose, and cellobiose derivatives) for aqueous one-pot synthesis of gold (Au) and silver (Ag) nano -structure glycoconjugates (NSs), and iron metal-organic framework glycoconjugates (FeMOFs). This work aims to test whether differences in the surface chemistry of the inorganic nanostructures play roles in revealing their toxicities towards bacterial cells and cancerous cell lines. As of the first step, biological activity of AuNSs, AgNSs, and FeMOFs were tested against a variety of gram (-) and gram (+) bacterial strains, where AgNSs possessed moderate to high antibacterial activities against all the tested bacterial strains, while AuNSs and FeMOFs showed their bacterial toxicity mostly depending on the strain. Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) determination studies were performed for the nanostructure glycoconjugates, for which mu g/mL MBC values were obtained such as (Cellobiose p-aminobenzoic acid_AgNS) CBpAB_AgNS gave 50 mu g/mL MBC value for P.aeruginosa and S.kentucy. The activity of selected sugar ligands and corresponding glycoconjugates were further tested on MDA-MB-231 breast cancer and A549 lung cancer cell lines, where se-lective anticancer activity was observed depending on the surface chemistry as well. Besides, D-penicillamine was introduced to galectin specific sugar ligand coated AuNS glycoconjugates, which showed very strong anticancer activities even at low doses. Overall, the importance of this work is that the surface chemistry of the inorganic nanostructures can be critical to reveal their toxicity towards bacterial cells and cancerous cell lines.
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    COVID-19: booster(s) vs. hospitalization and Intensive Care Unit admission
    Toprak, OB; Akpolat, T; Uzun, O; Deniz, PP; Kokturk, N; Varol, A; Guzel, E; Ercelik, M; Gultekin, O; Guner, R; Turan, S; Bekta, SG; Coskun, N; Bakan, N; Yakar, MN; Kutsoylu, OE; Ergan, B; Baris, SA; Basyigit, I; Boyaci, H; Cetinkaya, F; Colak, H; Aykac, N; Ketencioglu, BB; Yüce, ZT; Isik, SA; Yilmaz, ES; Karaoglanoglu, S; Safgi, SB; Ozkan, G; Kose, N; Kizilirmak, D; Havlucu, Y; Nural, S; Kerget, F; Sunal, O; Yuksel, A; Dursun, ZB; Deveci, F; Kuluozturk, M; Ataoglu, O; Dursun, M; Keskin, S; Sezgin, ME; Sezgin, ENA; Eser, F; Akyildiz, L; Almaz, MS; Kayaaslan, B; Hasanoglu, I; Bayrak, M; Gümüs, A; Sagcan, G; Cuhadaroglu, C; Kucuk, H; Onyilmaz, T; Mete, B; Kilinc, O; Itil, BO
    OBJECTIVE: As the pandem-ic continues, different vaccine protocols have been implemented to maintain the protection of vaccines and to provide protection against new variants. The aim of this study was to as-sess hospitalized patients' vaccination status and document the efficacy of boosters.PATIENTS AND METHODS: The patients that were hospitalized due to COVID-19 were enrolled from 28 hospitals in Turkey for five months from September 2021. 5,331 confirmed COVID-19 pa-tients from collaborating centers were random-ly enrolled to understand/estimate the distri-bution of vaccination status in hospitalized pa-tients and to compare the efficacy of vaccina-tion/booster protocols.RESULTS: 2,779 men and 2,552 women of which 2,408 (45.2%) were admitted to Intensive Care Units participated in this study. It was found that the highest risk reduction for all age groups was found in groups that received 4 doses. Four doses of vaccination for every 3.7 people under 50 years of age, for every 5.7 people in the 50-64 age group, and for every 4.3 people over 65 years of age will prevent 1 patient from being admitted to intensive care. Regardless of the type of vaccine, it was found that the risk of ICU hospitalization decreased in those who were vaccinated compared to those who were not vaccinated. Regardless of the type of vaccine, the ICU risk was found to decrease 1.25-fold in those who received 1 or 2 doses of vaccine, 1.18-fold in those who received 3 dos-es, and 3.26-fold in those who received 4 doses.CONCLUSIONS: The results suggested that the addition of a fourth dose is more effective in preventing intensive unit care even in disad-vantaged.