Publications by authors named "Aytac U"

Background: AI for medical diagnosis has made a tremendous impact by applying convolutional neural networks (CNNs) to medical image classification and momentum plays an essential role in stochastic gradient optimization algorithms for accelerating or improving training convolutional neural networks. In traditional optimizers in CNNs, the momentum is usually weighted by a constant. However, tuning hyperparameters for momentum can be computationally complex.

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Background: Next-generation sequencing in cancer research may reveal germline variants of clinical significance. We report patient preferences for return of results and the prevalence of incidental pathogenic germline variants (PGVs).

Patients And Methods: Targeted exome sequencing of 202 genes was carried out in 1000 advanced cancers using tumor and normal DNA in a research laboratory.

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CD26 is an antigen with key role in T-cell biology and is expressed on selected subsets of aggressive T-cell malignancies. To elucidate the role of CD26 in tumor behavior, we examine the effect of CD26 depletion by small interfering RNA transfection of T-anaplastic large cell lymphoma Karpas 299. We show that the resultant CD26-depleted clones lose the ability to adhere to fibronectin and collagen I.

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CD26 is a Mr 110,000 surface-bound glycoprotein with diverse functional properties, including having a key role in normal T-cell physiology and the development of certain cancers. In this article, we show that surface expression of CD26, especially its intrinsic dipeptidyl peptidase IV (DPPIV) enzyme activity, results in enhanced topoisomerase IIalpha level in the B-cell line Jiyoye and subsequent in vitro sensitivity to doxorubicin-induced apoptosis. In addition, we show that expression of CD26/DPPIV is associated with increased phosphorylation of p38 and its upstream regulators mitogen-activated protein kinase kinase 3/6 and apoptosis signal-regulating kinase 1 and that p38 signaling pathway plays a role in the regulation of topoisomerase IIalpha expression.

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CD26 is a 110 kDa surface-bound ectopeptidase with intrinsic dipeptidyl peptidase IV (DPP IV) activity, which has multiple biological functions. In this review, we will focus specifically on work demonstrating that CD26 has a key role in immune function as a T cell activation molecule and a regulator of the functional effect of selected biological factors through its DPP IV enzyme activity. As further evidence of the important role played by this multifaceted molecule in immune regulation, we will also discuss experimental attempts from our laboratory and others to influence immune-mediated conditions through CD26 monoclonal antibodies and DPP IV activity with various agents, including anti-CD26 monoclonal antibodies and DPP IV chemical inhibitors.

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CD26/dipeptidyl peptidase IV (DPPIV) is a cell surface-bound ectopeptidase with important roles in T-cell activation and tumour biology. We now report that CD26/DPPIV enhances sensitivity to apoptosis induced by the antineoplastic agents doxorubicin and etoposide. In particular, CD26/DPPIV presence is associated with increased susceptibility to the mitochondrial pathway of apoptosis, documented by enhanced cleavage of poly (ADP ribose) polymerase (PARP), caspase-3 and caspase-9, Bcl-xl, and Apaf-1, as well as increased expression of death receptor 5 (DR5).

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T-large granular lymphocyte lymphoproliferative disorder (T-LGL LPD) is an indolent disease characterized by prolonged cytopenia and the presence of circulating large granular lymphocytes in the patient's peripheral blood. Although the disease is commonly thought of as indolent, most patients eventually require therapy because of recurrent infections secondary to neutropenia as well as a need for frequent blood product transfusions. CD26 is a 110-kDa surface glycoprotein with an essential role in T-cell function, including being a marker of T-cell activation and a mediator of T-cell activating signals.

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CD26/dipeptidyl peptidase IV (DPPIV) is a surface antigen with multiple functions, including a role in T-cell activation and the development of certain human cancers. We previously demonstrated that CD26/DPPIV enhanced sensitivity of Jurkat cells to doxorubicin. We now show that expression of CD26/DPPIV enhanced sensitivity of CD26 Jurkat transfectants to G(2)-M arrest mediated by the antineoplastic agent etoposide.

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CD26, a M(r) 110,000 surface-bound ectopeptidase with dipeptidyl peptidase IV (DPPIV) activity, has an array of diverse functional properties, with a role in T-cell physiology and the development of certain human cancers. In this study, we report that surface expression of CD26, through its associated DPPIV enzyme activity, enhanced sensitivity of Jurkat T-cell transfectants to G(2)-M arrest induced by the chemotherapeutic drug, doxorubicin. This was associated with disruption of cell cycle-related events, including hyperphosphorylation and inhibition of p34(cdc2) kinase activity, phosphorylation of cdc25C, and alteration in cyclin B1 expression.

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CD26 is a M(r) 110,000 surface glycoprotein with diverse functional properties, including having a potentially significant role in tumor development, and antibodies to CD26 mediate pleomorphic cellular functions. In this report, we show that binding of soluble anti-CD26 monoclonal Ab 1F7 inhibits the growth of the human CD30+ anaplastic large cell T-cell lymphoma cell line Karpas 299 in both in vitro and in vivo experiments. In vitro experiments show that 1F7 induces cell cycle arrest at the G1-S checkpoint, associated with enhanced p21 expression that is dependent on de novo protein synthesis.

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Cytogenetic and molecular studies were performed on 20 interferon-alpha receiving Turkish chronic myelocytic leukemia patients. Four different restriction endonucleases and bcr-G probe were used for southern blot analysis to detect rearrangements of the bcr gene. The RT-PCR method was also applied to detect chimeric bcr/abl mRNA.

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The INK4 cyclin dependent kinase inhibitors (CDKI), such as p15(INK4B) and p16(INK4A), block cell cycle progression from G to S phase. This is mediated by inhibition of phosphorylation of proteins, including the retinoblastoma susceptibility protein (Rb), by cyclin dependent kinases. Ectopic over-expression of the p16(INK4A) CDKI can inhibit growth of cell lines depending on Rb status.

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Inhibition of cyclin dependent kinases (CDK) by cyclin dependent kinase inhibitors (CDKI) blocks cell cycle progression and inhibits cellular proliferation. The archetypical member of the INK4 CDKI family, p16INK4A (also called CDKN2), is a tumor suppressor frequently deleted or mutated in certain neoplasms and many cell lines. Because p19INK4D has strong structural and functional similarity to p16INK4A, we have assessed its role as a tumor suppressor.

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Queuosine (Q nucleoside) is a highly modified guanosine analog and is present only in the first position of the anticodons of tRNA(Tyr), tRNA(His), tRNA(Asn) and tRNA(Asp). The levels of Q in normal human brain and two different types of human brain tumors (meningiomas and astrocytomas) were determined by using an enzymatic assay method. tRNAs isolated from tumor tissues contained decrease amounts of Q when compared to tRNAs from normal (i.

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