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Dive into the research topics where Senem Karatayli is active.

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Featured researches published by Senem Karatayli.


Clinical Infectious Diseases | 2012

Entecavir Treatment of Chronic Hepatitis D

Gökhan Kabaçam; F. Oğuz Önder; Mustafa Yakut; Gülseren Seven; Senem Karatayli; Ersin Karatayli; Berna Savas; Ramazan Idilman; A. Mithat Bozdayi; Cihan Yurdaydin

BACKGROUND Hepatitis D virus (HDV) requires hepatitis B surface antigen (HBsAg) to propagate infection and cause disease. Entecavir is a nucleoside analog with potent antiviral efficacy, and in the woodchuck animal model it also decreased hepatitis B virus (HBV) cccDNA and woodchuck surface antigen. The aim of this study was to investigate the efficacy of entecavir in chronic hepatitis D (CHD). METHODS This single-center study was conducted in patients with compensated liver disease. All patients had to have detectable hepatitis HDV RNA and elevated levels of alanine aminotransferase (ALT). Entecavir was given at a dosage of 1 mg/d for 1 year. The primary end point was achievement of undetectable HDV RNA at the end of treatment. RESULTS Thirteen consecutive patients were assessed. All patients had detectable HDV RNA, and 8 had detectable HBV DNA at baseline. At the end of treatment, HBV DNA became undetectable in all patients (P = .001). No significant decline in HDV RNA, ALT, or quantitative HBsAg levels was observed. The primary end point of undetectable HDV RNA at the end of treatment was achieved in 3 patients who had significantly lower baseline HDV RNA levels than nonresponders (2.99 log(10) copies/mL ± .70 vs 4.68 ± .97; P = .0185). In all 3 patients, ALT levels were also normal at the end of treatment. CONCLUSIONS One year of entecavir treatment is ineffective in CHD. Any generalized beneficial effect of nucleoside/nucleotide analog treatment may necessitate prolonged treatment. Patients with CHD with HBV dominance, which is likely to occur in the later phases of CHD, may be a reasonable patient cohort in which to target nucleoside/nucleotide analog therapy.


Proteome Science | 2011

Effect of Turkish propolis extracts on proteome of prostate cancer cell line

Yaşam Barlak; Orhan Deger; Meltem Çolak; Senem Karatayli; A.M. Bozdayi; Fulya Balaban Yucesan

BackgroundPropolis is a natural, resinous hive product that has several pharmacological activities. Its composition varies depending on the vegetation, climate, season and environmental conditions of the area from where it was collected. Surface enhanced laser desorption ionization time of flight mass spectrometry (SELDI-TOF MS) is a proteomic approach which has been used in cancer proteomics studies. Prostate cancer is one of the most commonly diagnosed cancers in men. It has shown that nutritional supplements rich in polyphenolic compounds such as propolis play a significant role in prostate cancer chemoprevention. The aim of this study is to evaluate if protein expression profile in PC-3 prostate cancer cell lines could be differentiated when incubated with dimethyl sulfoxide and water extracts of Turkish propolis.ResultsThe antioxidant potentials of dimethyl sulfoxide and water extracts of propolis were found in correlation with the amount of total phenolic compounds of them. Dimethyl sulfoxide and water extracts of propolis of 20 μg/mL reduced the cell viability to 24.5% and 17.7%, respectively. Statistically significant discriminatory peaks between control PC-3 cells and dimethyl sulfoxide extract of propolis-treated PC-3 cells were found to be the proteomic features at m/z 5143, 8703, 12661, 20184 and 32794, detected by CM10 ProteinChip, and the peak at m/z 3772, detected by Q10 ProteinChip. Between control PC-3 cells and water extract of propolis-treated PC-3 cells, statistically significant discriminatory peaks were found to be the proteomic features at m/z 15846, 16052 and 24658, detected by CM10 ProteinChip and the peaks at m/z 10348, 10899 and 11603, detected by Q10 ProteinChip.ConclusionsIt was concluded that dimethyl sulfoxide and water extracts of Turkish propolis may have anti-proliferative activity through differentiating protein expression profile in PC-3 prostate cancer cell lines along with their antioxidant capacity.


Journal of Clinical Virology | 2012

Molecular characterization of a novel entecavir mutation pattern isolated from a multi-drug refractory patient with chronic hepatitis B infection

Ersin Karatayli; Senem Karatayli; Kubilay Çinar; Selma Gokahmetoglu; Kadri Güven; Ramazan Idilman; Cihan Yurdaydin; A. Mithat Bozdayi

BACKGROUND Prolonged antiviral treatment results in selection and accumulation of resistant strains in quasispecies pool in hepatitis B virus (HBV) infection. OBJECTIVES The aim of this study was to characterise a novel HBV pattern which shows resistance to lamivudine, adefovir dipivoxil and entecavir using in vitro phenoyping assay. STUDY DESIGN A male 36 years old patient diagnosed with anti HBe-positive chronic hepatitis B (CHB) had received lamivudine treatment for 7 years following an initial unsuccessfull interferon treatment. The therapy had been switched to adefovir and then to entecavir when breakthrough occcured during each treatment. This led only to a temporary HBV DNA decline which soon was followed by viral breakthrough despite the lack of known entecavir resistance mutations. Patient died after 9 months of entecavir treatment from liver failure. A total of 434 clones from 6 different serum samples were analysed retrospectively. HBV genomes bearing mutation patterns suggestive of antiviral resistance were analysed by in vitro phenotyping assay. RESULTS Dominance of a clone carrying L80LV, L91I, M204I, S219A, N238D, Y245H changes was detected in the last serum sample of the patient just before his death. This pattern displayed 30.4 fold resistance to entecavir when compared with the wild type HBV by in vitro phenotyping assay. CONCLUSION A novel mutation pattern showing a high degree of resistance to entecavir was documented. In this pattern, the S219A and Y245H mutations mainly seem to contribute to the emergence of ETV resistance.


Archives of Virology | 2011

Complete genome sequences and phylogenetic analysis of hepatitis delta viruses isolated from nine Turkish patients

İnci Çelik; Ersin Karatayli; Emrah Çevik; S. Gökçe Kabakçı; Senem Karatayli; Bedia Dinç; Kubilay Çinar; Kendal Yalçin; Ramazan Idilman; Cihan Yurdaydin; A. Mithat Bozdayi

Hepatitis delta virus (HDV) is a subviral agent of hepatitis B virus (HBV), and its life cycle is dependent on HBV. It is commonly accepted that HDV has eight distinct genotypes. In this study, the complete nucleotide sequences of HDV genomes isolated from nine Turkish patients were obtained by RT-PCR using two pairs of primers that cover the entire HDV genome. PCR products were sequenced directly. The results showed that these 9 isolates were approximately 1680 base pairs in length and clustered in the genotype HDV-1 branch when phylogenetic analysis was done with the sequences together with the complete sequences of HDV genomes representing each genotype retrieved from GenBank. Analysis of a portion of the large hepatitis D antigen (L-HDAg) gene showed that sequence similarity among these Turkish isolates is between 87.4 and 97.1%, and the Turkish isolates have the most sequence similarity to HDV-1 (90.5%), while they have the least sequence similarity to HDV-3 (64.1%). Full-genome analysis indicates that the sequence similarity is between 80.7 and 95.4%, and the highest sequence similarity is 84.8% (between the Turkish isolates and HDV-1). The lowest sequence similarity is 56.4% (between the Turkish isolates and HDV-3). In conclusion, phylogenetic analysis shows that the Turkish HDV isolates belong to HDV-1.


Antiviral Therapy | 2014

Efficacy of tenofovir in adefovir-experienced patients compared with treatment-naive patients with chronic hepatitis B.

Onur Keskin; Ormeci Ac; Baran B; Gökhan Kabaçam; Tüzün A; Ersin Karatayli; Filiz Akyuz; Senem Karatayli; A.M. Bozdayi; Onel D; Badur S; Ramazan Idilman; Sabahattin Kaymakoglu; Cihan Yurdaydin

BACKGROUND Tenofovir (TDF) has similar antiviral efficacy in both treatment-naive and lamivudine-resistant chronic hepatitis B (CHB) patients. Data on TDF use in patients with adefovir (ADV) resistance is inconsistent. The aim of our study was to assess antiviral efficacy of TDF against nucleoside analogue-naive (NN) and ADV-resistant (ADV-R) CHB and suboptimal responders to ADV (ADV-S). METHODS A database of 135 CHB patients treated with TDF was analysed. A total of 37 patients with incomplete data were excluded and analysis was performed in 98 (44 NN, 30 ADV-R and 24 ADV-S). Patients with primary ADV-R mutations had either A181T/V or N236T mutations or both. HBV DNA was measured at 3-month intervals until month 24. Primary outcome measures were comparison of the decline of HBV DNA between the three treatment groups. RESULTS NN patients had higher baseline HBV DNA compared with ADV-R and ADV-S patients (6.08 log10 IU/ml versus 5.53 and 4.88, respectively; P=0.002). By exponential regression analysis, HBV DNA decline kinetics differed between the three groups. HBV DNA decline was faster in NN patients compared to ADV-R and ADV-S CHB patients (P=0.002 and P=0.004, respectively). Undetectable HBV DNA was achieved in 77.2%, 60% and 75% of NN, ADV-R and ADV-S CHB patients, respectively, at month 12 (P= not significant). CONCLUSIONS HBV DNA decline is slower in ADV-experienced patients compared with treatment-naive patients. The clinical significance of this slow response may be important in patients with critical liver reserve and high viral load. Optimal combination treatment (TDF+ entecavir) could be considered in these patients.


Journal of Viral Hepatitis | 2014

Tumour necrosis factor-alpha, interleukin-10, interferon-gamma and vitamin D receptor gene polymorphisms in patients with chronic hepatitis delta.

Senem Karatayli; Z. E. Ulger; A. A. Ergul; Onur Keskin; Ersin Karatayli; R. Albayrak; Muhip Özkan; Ramazan Idilman; Kendal Yalçin; Hakan Bozkaya; Ozden Uzunalimoglu; Cihan Yurdaydin; A.M. Bozdayi

No data exist to assess certain polymorphisms that have a potential effect on the immune response in patients with chronic hepatitis delta (CHD). The aim of this study was to investigate polymorphisms in 6 polymorphic sites: IL‐10 ‐1082 (rs1800896), IL‐10 ‐627 (rs1800872), IFN‐γ +874 (rs62559044), TNF‐α ‐308 (rs1800629), vitamin D receptor (VDR) FokI (rs2228570) and VDR TaqI (rs731236). The genotypes of 67 patients with CHD and 119 patients with chronic hepatitis B (CHB) were compared. In addition, 56 individuals with resolved hepatitis B virus (HBV) infection were used as a control group for patients with CHB. Polymorphisms in TNF‐α, IL‐10, and VDR genes were analysed using polymerase chain reaction/restriction fragment length polymorphism methods. The IFN‐γ gene polymorphism was detected by allele‐specific polymerase chain reaction (PCR). Patients with CDH were more likely to have advanced liver disease compared with patients with CHB (P < 0.0001). IL‐10 ‐1082 and VDR TaqI polymorphisms showed significant differences between patients with CHD and CHB. The high secretory IL‐10 ‐1082 genotype GG was less frequent in CHD compared with patients with CHB and resolved HBV (17.7%, 37.4% and 47.1%, respectively (P < 0.05 for CHD vs CHB and resolved HBV). The frequency of the high secretory VDR TaqI TT genotype was 86.6% in patients with CHD, 62.7% in patients with CHB and 62.5% in resolved HBV individuals (CHD vs CHB: P < 0.05). None of the polymorphisms analysed had an effect on HBV persistence. IL‐10 ‐1082 and VDR TaqI polymorphisms may contribute to the more severe liver disease associated with CHD compared with CHB.


Hepatology | 2018

Optimizing lonafarnib treatment for the management of chronic delta hepatitis: The LOWR HDV‐1 study

Cihan Yurdaydin; Onur Keskin; Çağdaş Kalkan; Fatih Karakaya; Aysun Çalişkan; Ersin Karatayli; Senem Karatayli; A. Mithat Bozdayi; Christopher Koh; Theo Heller; Ramazan Idilman; Jeffrey S. Glenn

In a proof‐of‐concept (POC) study, the oral prenylation inhibitor, lonafarnib (LNF), decreased hepatitis D virus (HDV) RNA during 4 weeks of treatment. Here, we explored optimal LNF regimens. Fifteen patients (five groups; 3 per group) completed dosing as follows: (1) LNF 200 mg twice‐daily (BID; 12 weeks); (2) LNF 300 mg BID (12 weeks); (3) LNF 100 mg thrice‐daily (5 weeks); (4) LNF 100 mg BID + pegylated interferon alfa (PEG‐IFNα) 180 μg once‐weekly (QW; 8 weeks); and (5) LNF 100 mg BID + ritonavir (RTV) 100 mg once‐daily (QD; 8 weeks). Tolerability and efficacy were assessed. Higher LNF monotherapy doses had greater decreases in HDV viral load than achieved in the original POC study. However, this was associated with increased gastrointestinal adverse events. Addition of RTV 100 mg QD to a LNF 100 mg BID regimen yielded better antiviral responses than LNF 300 mg BID monotherapy and with less side effects. A similar improvement was observed with LNF 100 mg BID + PEG‐IFNα 180 μg QW. Two of 6 patients who received 12 weeks of LNF experienced transient posttreatment alanine aminotransferase (ALT) increases resulting in HDV‐RNA negativity and ALT normalization. Conclusion: The cytochrome P450 3A4 inhibitor, RTV, allows a lower LNF dose to be used while achieving higher levels of postabsorption LNF, yielding better antiviral responses and tolerability. In addition, combining LNF with PEG‐IFNα achieved more substantial and rapid HDV‐RNA reduction, compared to historical responses with PEG‐IFNα alone. Twelve weeks of LNF can result in posttreatment HDV‐RNA negativity in some patients, which we speculate results from restoring favorable immune responses. These results support further development of LNF with RTV boosting and exploration of the combination of LNF with PEG‐IFN. (Hepatology 2018;67:1224‐1236)


Journal of Clinical Virology | 2014

A one step real time PCR method for the quantification of hepatitis delta virus RNA using an external armored RNA standard and intrinsic internal control

Ersin Karatayli; Yasemin Çelik Altunoğlu; Senem Karatayli; S. Gökçe K. Alagöz; Kubilay Çinar; Kendal Yalçin; Ramazan Idilman; Cihan Yurdaydin; A. Mithat Bozdayi

BACKGROUND Hepatitis delta virus (HDV) RNA viral load measurement is critical in diagnosis and monitoring the response to antiviral treatment. OBJECTIVES Our aim is to design a real time PCR method for accurate quantitation of HDV RNA in clinical specimens using an armored RNA as external standard, and an intrinsic internal control. STUDY DESIGN A plasmid bearing delta antigen region of genotype I HDV genome was used to develop an armored RNA. Serial dilutions of the armored HDV RNA standard with 10(12)copy/mL were used as standards for quantitation. A primer-probe set derived from HDAg region was used in one step EZ RT PCR kit chemistry which uses rTth enzyme allowing reverse transcription and polymerization in the same tube. The kit also uses the advantage of uracil-N-glycosylase (UNG) enzyme treatment to prevent PCR contamination. RESULTS The established assay has a dynamic range of 10(2)-10(11)copy/mL with a PCR efficiency of 96.9%. Detection limit was 858±32copy/mL with 95% confidence interval. Intra- and inter-assay variabilities were low for high, medium and low levels of viremia. Incorporation of freely circulating GAPDH in serum into the assay as an intrinsic internal control prevented false negative results and failures in PCR amplifications due to inhibitors, inefficient extraction procedures or enzymatic reactions. CONCLUSION In conclusion, this study defines a novel assay for sensitive and reliable quantification of HDV RNA using an armored HDV RNA as a standard and GAPDH in plasma or serum as an intrinsic internal control in a single tube.


Antiviral Therapy | 2012

Clonal analysis of the quasispecies of antiviral-resistant HBV genomes in patients with entecavir resistance during rescue treatment and successful treatment of entecavir resistance with tenofovir.

Ersin Karatayli; Ramazan Idilman; Senem Karatayli; Cevik E; Mustafa Yakut; Gülseren Seven; Gökhan Kabaçam; A.M. Bozdayi; Cihan Yurdaydin

BACKGROUND Clonal analysis of quasispecies of resistant HBV genomes in patients with entecavir (ETV) resistance receiving lamivudine (3TC) plus adefovir (ADV) rescue therapy has never been performed. METHODS A sample of 10 patients with ETV resistance who were switched to 3TC+ADV treatment were analysed for changes in viral quasispecies. Serum samples at baseline, and at months 3 and 6 of 3TC+ADV treatment could be clonally analysed in 7 of 10 patients; 3-82 clones per sample (total 1,068 clones, mean 63) were sequenced. RESULTS 3TC+ADV therapy led to a modest decline in HBV DNA. Almost all clones had L180M and M204V 3TC resistance mutations before and during combination therapy. All clones had ≥1 of the S202G, T184F, T184A, T184L, T184I and M250V ETV resistance mutations. The percentages of detected clones bearing 3TC (rtL180M and rtM204V) and ETV mutations did not change with rescue 3TC+ADV therapy. In 7 of 8 patients with detectable HBV DNA (median 5.17 log(10) copies/ml) after a median 24 months of ADV therapy, HBV DNA became undetectable with 3TC plus tenofovir after 6 months of treatment. CONCLUSIONS In patients with ETV resistance tenofovir is effective. Clonal analysis data indicate no selection of specific HBV mutants during rescue 3TC+ADV.


Liver International | 2015

Interleukin-28 gene polymorphisms may contribute to HBsAg persistence and the development of HBeAg-negative chronic hepatitis B.

Senem Karatayli; Mithat Bozdayi; Ersin Karatayli; Tuğba Öztürk; Abbas A. Husseini; Rabia Albayrak; Muhip Özkan; Zeynep Kalaylioglu; Kendal Yalçin; Kubilay Çinar; Ramazan Idilman; Cihan Yurdaydin

Aim of this study was to investigate whether a potential association exists between several single nucleotide polymorphisms (SNPs) of the IL‐28B gene (rs12979860, rs1188122, rs8099917, rs8105790, rs12980275) and HBsAg persistence. Further, a potential effect on the development of HBeAg‐negative CHB vs. inactive HBsAg carrier state was assessed in a genotype D HBV cohort. A cohort of chronic HDV patients was also used to see if they behave differently compared to chronic HBV patients.

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