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İstanbul, Turkey

Tatli A.M.,Van Training and Research Hospital | Urakci Z.,Dicle University | Kalender M.E.,University of Gaziantep | Arslan H.,Van Training and Research Hospital | And 2 more authors.
Asian Pacific Journal of Cancer Prevention | Year: 2015

Background: Elevated serum alpha-fetoprotein (AFP) levels in adults are considered abnormal. This parameter is used mostly in the diagnosis and follow-up of hepatocellular carcinomas and yolk sac tumors. Among the other rare tumors accompanied with elevated serum AFP levels, gastric cancer is the most common. In this study, we evaluated the follow-up and comparison of the treatment and marker response of patients with metastatic gastric cancer who had elevated serum AFP levels. Materials and Methods: We performed a retrospective study, including all consecutive patients with advanced gastric cancer, who received systemic chemotherapy with elevated AFP level. Results: Seventeen metastatic gastric cancer patients with elevated AFP levels at the time of diagnosis were evaluated. Fourteen (82.4%) were males and three (17.6%) were females. The primary tumor localization was the gastric body in 8 (76.4%), cardia in 7 (41.2%), and antrum in 2 (11.8%). Hepatic metastasis was observed in 13 (76.4%) at the time of diagnosis. When the relationship of AFP levels and carcinoembryonic antigen (CEA) response of the patients with their radiologic responses was evaluated, it was found that the radiologic response was compatible with AFP response in 16 (94.1%) patients and with CEA response in 12 (70.6%); however, in 5 (29.4%) patients no accordance was observed between radiological and CEA responses. Conclusions: Follow-up of AFP levels in metastatic gastric cancer patients with elevated AFP levels may allow prediction of early treatment response and could be more useful than the CEA marker for follow-up in response evaluation. Source


Palabiyik B.,IstanbulUniversity | Jafari Ghods F.,IstanbulUniversity | Onay Ucar E.,IstanbulUniversity
Genetics and Molecular Research | Year: 2014

The relationship between glucose repression and the oxidative stress response was investigated in Schizosaccharomyces pombe wild type cells (972h-) and glucose repression resistant mutant type cells (ird11). We aimed to reveal the mechanism of simultaneous resistance to glucose repression and oxidative stress in ird11 mutants. Compared to the wild type, the expression of the sty1 gene was not altered in the ird11 mutant under normal growth conditions, but decreased after exposure to H2O2. This effect was clearly explained by the immunoblotting results, which showed elevated levels of a much more stable phosphorylated form of Sty1 mitogen-activated protein kinase in the ird11 mutant. Increased ght3 gene expression levels were also found, which may play a role in protecting the ird11 mutant from the deleterious effects of oxidative stress. In addition, decreased expression levels of glycolytic enzyme enolase- and thiamine synthesis/transport-related genes were detected. This might have resulted from the flux redirection toward mitochondrial respiration, which would enhance NADPH generation to prevent the high reactive oxygen species accumulation that is generated by respiration. Some evidence supported a flux shift toward fermentation as well as respiration. We conclude that a defect in the glucose-sensing signaling pathway in ird11 mutants likely causes erroneous low glucose-sensing signaling and high ATP production. This most likely occurs because high glucose availability in the medium induces an impairment in the respiratory chain and fermentation balance in these cells, which might explain the glucose repression and oxidative stress resistance in ird11 compared to the wild type. © FUNPEC-RP. Source


Gurel F.,IstanbulUniversity | Gurel F.,Research and Application Center for Biotechnology and Genetic Engineering | Arican E.,IstanbulUniversity | Gozukirmizi N.,IstanbulUniversity | Ari S.,IstanbulUniversity
Scientific Research and Essays | Year: 2011

Genetically modified (GM) crops are the plant varieties carrying single or multiple transgenes in their genomes modified by recombinant DNA technology. Detection of transgenic elements associated with GM crops is an important issue for their traceability in food chain and also for the risk assessments related to environment and transgene introduction into human diet. A number of methods have been developed for screening GM crop products with the aim of increasing reliability and molecular sensitivity. This review article is focused on the published methods which are mainly based on PCR and DNA hybridizations as well as biosensors as a recently utilized technology. DNA hybridization methods including probe immobilization on solid surfaces and subsequent hybridization by target DNA are variously depended on surface types, probe labeling conditions or some modifications such as the use of peptide nucleic acids (PNA). Quantitative real-time PCR (qRT-PCR) is the most routinely used and compatible method for quantification which is a crucial issue in GMO content analyses. Finally, biosensors represent more advanced assays with high detection sensitivity provided by specific transducers sense DNA hybridization events. Progress in technical implementations related to GM crop analyses will contribute not only to environmental safety but also to guarantee global market functioning and the consumer rights to choose. © 2011 Academic Journals. Source

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