Browsing by Author "Aktas, S"

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    Effect of apoptosis and response of extracellular matrix proteins after chemotherapy application on human breast cancer cell spheroids
    Oktem, G; Vatansever, S; Ayla, S; Uysal, A; Aktas, S; Karabulut, B; Bilir, A
    Multicellular Tumor Spheroid (NITS) represents a three-dimentional structural form of tumors in laboratory conditions, and it has the characteristics of avascular micrometastases or intervascular spaces of big tumors. Recent studies indicate that extracellular matrix (ECM) proteins play a critical role in tumor metastasis, therefore normal and cancer cells require an ECM for survival, proliferation and differentiation. Doxorubicin and Docetaxel are widely used in the therapy of breast cancer, as well as in in vivo and in vitro studies. In this study, we examined the effect of apoptosis and proliferation of cells on the human breast cancer cell line, MCF-7, by using p53, bcl-2 and Ki67 gene expression, and the tendency to metastasis with extracellular matrix proteins, laminin and type IV collagen after chemotherapy in the spheroid model. The apoptotic cell death in situ was detected by TUNEL method. TUNEL-positive cells and positive immunoreactivities of laminin, type IV collagen, p53 and, bel-2 were detected in the control group. There was no laminin and type IV collagen immunoreactivities in spheroids of drug groups. While TUNEL-positive cells and p53 immunoreactivity were detected in Docetaxel, Doxorubicin and Docetaxel/Doxorubicin groups, p53 immunoreactivity was not observed in the Docetaxel group. There was no bcl-2 immunoreactivity in either drug group. In addition, we did not detect Ki67 immunoreactivity in both control and drug treatment groups. However, the absence of Ki67 protein in MCF-7 breast multicellular tumor spheroids is possibly related to the cells in GO or S phase. These agents may affect the presence of ECM proteins in this in vitro model of micrometastasis of spheroids. These findings suggest that the possible mechanism of cell death in Doxorubicin and Docetaxel/Doxorubicin treatment groups is related to apoptosis through the p53 pathway. However, we considered the possiblity that there is another control mechanism for the Docetaxel group.
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    Comparison study on SMC and grain-oriented laminated steel core for small-size axial flux permanent-magnet synchronous machines
    Karabulut, Y; Mese, E; Ayaz, M; Aktas, S
    This study aims to compare the soft magnetic composite (SMC) and grain-oriented (GO) steel stator axial flux permanent-magnet synchronous machine (AFPMSM) in terms of performance and iron losses. Stator cores are manufactured using both materials to perform experimental performance tests. The produced machines are designed for pump propulsion systems in left ventricular assist devices as an application area. The machines are modeled with several analytical equations, and iron losses and performance tests are carried out with AFPMSMs, finite element methods, and experimental setups. Our findings show that the torque density is higher in the GO steel stator AFPMSMs that can produce 15.07 percent more torque. GO steel material experimentally has 20.33 percent less iron loss as SMC material since the loss value per kilogram for SMC material is higher than that for GO steel. In addition, the saturation value of the SMC material is lower than that of the GO material according to the magnetic flux density value.
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    The effects of disodium pentaborate decahydrate on in-vivo neuroblastoma animal model
    Altun, Z; Serinan, EO; Aktas, S; Calisir, M; Aydin, M; Yilmaz, O; Korkmaz, M; Olgun, N
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    Treatment and prophylaxis with sucralfate ameliorates hypoxia/reoxygenation-induced intestinal injury in pup rats
    Sencan, AB; Sencan, A; Aktas, S; Habif, S; Kabaroglu, C; Parildar, Z; Karaca, I
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    Caffeine use in preterm neonates: national insights into Turkish NICU practices
    Unal, S; Beken, S; Ince, DA; Turan, O; Toygar, AK; Ecevit, A; Akcan, AB; Akin, MA; Aktas, S; Ciftdemir, NA; Altuncu, E; Altunhan, H; Arcagok, BC; Armangil, D; Ozer, EA; Aydin, B; Bezirganoglu, H; Bilgin, L; Calisici, E; Calkavur, S; Celik, K; Celik, Y; Cetinkaya, B; Cetinkaya, M; Demirel, A; Demirel, G; Dogan, NN; Dogan, P; Durukan, M; Engur, D; Ercan, TE; Gokmen, Z; Varal, IG; Gulasi, S; Gunlemez, A; Gursoy, T; Toptan, HH; Hamitoglu, S; Isleyen, F; Iyigun, I; Kader, S; Kahvecioglu, D; Kayki, G; Kostu, M; Kurnaz, D; Mammadaliyev, T; Akin, IM; Narli, N; Okulu, E; Okur, N; Olukman, O; Ovali, F; Ozcan, B; Ozdemir, A; Ozdemir, O; Ozkan, H; Sandal, G; Sarici, D; Sivrikaya, C; Bilgin, BS; Sundus, S; Onay, OS; Simsek, H; Tandircioglu, UA; Tanriverdi, S; Tekgunduz, KS; Terek, D; Tunc, G; Tunc, T; Tutak, E; Tufekcioglu, E; Erdogan, FT; Ulu, E; Isik, DU; Uras, N; Uslu, SI; Unal, I; Yilmaz, FH; Moniri, A
    Objective: Caffeine is a proven medication used for the prevention and treatment of apnea in premature infants, offering both short- and long-term benefits. International guidelines provide a range of recommendations regarding the preterm population eligible for caffeine prophylaxis, including the timing, dosage, and duration of treatment. Our national guidelines, published prior to the most recent updates of the international guidelines, recommend the use of caffeine citrate starting from the first day after delivery for preterm infants with a gestational age of <28 weeks. For infants up to 32 weeks, if positive pressure ventilation is required, the decision should be made on an individual basis. This study aims to describe the variability in caffeine usage across neonatal intensive care units in our country. Methods: An online survey was sent to neonatologist who are members of the Turkish Neonatology Society to describe the variability in caffeine usage in neonatal intensive care units in our country. Results: We collected responses from 74 units. Prophylactic caffeine usage was observed as; GA <= 27(6/7): 98.6%, GA 28(0/7)-28(6/7): 89.0%, GA 29(0/7)-29(6/7): 75.3%, GA 30(0/7)-31(6/7): 53.4%. 62.2% of units reported administering loading dose within the first two hours. The initial maintenance dose was 5 mg/kg in 64.8% of units, 10 mg/kg in 32.4% of units, and intermediate dose in 5.3% of units. 47.3% of units reported no routine dose adjustment. The postmenstrual age that caffeine treatment was stopped was found to be 34 (min-max; 32-36) weeks for infants without apnea and respiratory support, 36 (min-max; 34-52) weeks for infants without apnea but any respiratory support. The time to discharge after treatment cessation was found as; 1-4 days: 37.8%, 5-7 days: 68.9%. Among the 56 units with multiple responsible physicians, 32.1% reported intra-unit variations. Conclusion: The significant differences in caffeine usage characteristics between and within units highlight the need for clear recommendations provided by standardized guidelines.
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    Efficiency of Bioflavonoids in the Prevention of Experimental Myringosclerosis
    Ilknur, AE; Dundar, R; Basoglu, S; Inan, S; Aktas, S; Aslan, H; Ozkul, Y; Ozturkcan, S; Katilmis, H
    Objectives/Hypothesis: It has been noted that some materials with anti-inflammatory and antioxidant effects decrease sclerotic lesions in experimental myringosclerosis. Our purpose in this study is to investigate the effect of micronized purified flavonoid fraction (MPFF), an antioxidant with anti-inflammatory effects, in experimental myringosclerosis in guinea pigs. Materials and Methods: Two study groups were formed. The first group was administered 100mg/kg/day MPFF by catheter for five days before myringotomy and 10 days after myringotomy, while the second group was administered distilled water by the same method, before and after myringotomy. On the 15th day of the study, after the tympanic membranes were examined otomicroscopically for myringosclerosis, they were removed by dissection together with the bone annulus, for histochemical and immunohistochemical examinations. Results: In the MPFF group, the otomicroscopical sclerosis score, inflammation score and tympanic membrane thickness were significantly less than those in the untreated group (p<0.05). It was also determined that the immunoactivity of the anti-VEGF, anti-TGF-beta, anti-eNOS, anti-iNOS, and anti-IL1-beta primary antibodies, which are known to have an important role in angiogenesis and inflammation, significantly decreased in the MPFF group (p<0.05). Conclusion: In conclusion, this study shows that orally administered MPFF can be efficient in the prevention of experimental myringosclerosis in guinea pigs.