Gökhan Dindar
Kocaeli University
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Publication
Featured researches published by Gökhan Dindar.
World Journal of Gastroenterology | 2011
Sadettin Hulagu; Omer Senturk; Cem Aygun; Orhan Kocaman; Altay Celebi; Tolga Konduk; Koç Dö; Goktug Sirin; Uğur Korkmaz; Ali Erkan Duman; Neslihan Bozkurt; Gökhan Dindar; Tan Attila; Yesim Gurbuz; Orhan Tarcin; Cem Kalayci
AIM To investigate the indication, feasibility, safety, and clinical utility of endoscopic submucosal dissection (ESD) in the management of various gastrointestinal pathologies. METHODS The medical records of 60 consecutive patients (34 female, 26 male) who underwent ESD at the gastroenterology department of Kocaeli University from 2006-2010 were examined. Patients selected for ESD had premalignant lesions or non-invasive early cancers of the gastrointestinal tract and had endoscopic and histological diagnoses. Early cancers were considered to be confined to the submucosa, with no lymph node involvement by means of computed tomography and endosonography. RESULTS Sixty ESD procedures were performed. The indications were epithelial lesions (n = 39) (33/39 adenoma with high grade dysplasia, 6/39 adenoma with low grade dysplasia), neuroendocrine tumor (n = 7), cancer (n = 7) (5/7 early colorectal cancer, 2/7 early gastric cancer), granular cell tumor (n = 3), gastrointestinal stromal tumor (n = 2), and leiomyoma (n = 2). En bloc and piecemeal resection rates were 91.6% (55/60) and 8.3% (5/60), respectively. Complete and incomplete resection rates were 96.6% (58/60) and 3.3% (2/60), respectively. Complications were major bleeding [n = 3 (5%)] and perforations [n = 5 (8.3%)] (4 colon, 1 stomach). Two patients with colonic perforations and two patients with submucosal lymphatic and microvasculature invasion (1 gastric carcinoid tumor, 1 colonic adenocarcinoma) were referred to surgery. During a mean follow-up of 12 mo, 1 patient with adenoma with high grade dysplasia underwent a second ESD procedure to resect a local recurrence. CONCLUSION ESD is a feasible and safe method for treatment of premalignant lesions and early malignant gastrointestinal epithelial and subepithelial lesions. Successful en bloc and complete resection of lesions yield high cure rates with low recurrence.
Indian Journal of Gastroenterology | 2013
Ugur Korkmaz; Ali Erkan Duman; Gökhan Dindar; Hasan Yilmaz; Ibrahim Hakki Dursun; Altay Celebi; Omer Senturk; Sadettin Hulagu
Sir: Inappropriate secretion of tumor necrosis factor alpha (TNF-α) leads to inflammation and tissue damage by causing excessive secretion of inflammatory cytokines especially IL-1 [1]. AntiTNF-α agents are used to treat a myriad of immune-based diseases. Although indicated in treating certain forms of psoriasis, TNF inhibitors have paradoxically been shown to cause or worsen psoriasis primarily in patients with underlying rheumatologic disease and inflammatory bowel diseases (IBD) [2, 3]. We present a case of plaque psoriasis in a patient with Crohn’s disease during adalimumab treatment. A 32-year-old female patient with the diagnosis of ileal Crohn’s disease for 5 years was started on adalimumab therapy (160 mg initially on day 1, followed by 80 mg on day 15, and a maintenance dose of 40 mg every other week) due to refractory disease. Following the loading dose, a marked improvement was seen in both clinical and laboratory indices (defined as a decrease in CDAI ≥100 points). In the fourth month of treatment, itchy irregular white desquamated plaques with surrounding hyperemia appeared on the extensor and partly flexor surfaces of the extremities and also on the scalp. Plaques with fissures were seen on the thenar parts of the hands (Fig. 1a, b). The patient was diagnosed with psoriasis. As psoriasis was believed to occur as a side effect of adalimumab, therapy was stopped and switched to methotrexate 15 mg/week plus infliximab 5 mg/kg/week in the 12th week of the treatment, laboratory findings were within normal range, and the patient suffered only from mild abdominal pain. Plaques were judged to show an improvement to a degree of approximately 90 % on the extremities and 50 % on the scalp. Treatment was maintained by adding topical therapies. Anti-TNF-α drugs play a key role in the treatment of IBD. Psoriasis is rarely seen in IBD patients using anti-TNF drugs and most of these cases are related to infliximab therapy [3–5]. The most common anti-TNF-α-related forms of psoriasis are plaque psoriasis and palmoplantar pustulosis [3, 5]. Signs occur after 1 to 96 months from the implementation of therapy [5]. Psoriasis development during anti-TNF-α therapy is believed to be a result of the disruption of the balance between TNF-α and interferon alpha [6]. Inhibition of TNF-α also leads to hyperproliferation of keratinocytes by decreasing levels of cytokines such as IL-6, IL-8, etc. [7]. Although there is no established treatment modality for such cases, stopping the offending drug provides a marked improvement. Switching to another drug from the same class, adding an immunomodulatory drug like methotrexate, and topical therapies (including vitamin D) are also recommended [3, 5, 6]. Although lesions might also heal during continuation of therapy, stopping the therapy yielded better responses [5]. In our case, both IBD and skin lesions (except scalp lesions) could be treated by stopping the offending drug and starting methotrexate along with infliximab (as Crohn’s disease was unresponsive to previous immunomodulatory therapies). Vitamin Dwhich has immunomodulatory effects (especially in plaque psoriasis) permits to lower the doses of other drugs used for the treatment of psoriasis [8]. Healing of plaques by vitamin D replacement is reported in adalimumab-induced psoriasis [9]. As skin lesions seen in IBD might be a manifestation of the disease, it should be always kept in mind that they might be the side effect of the drugs used for the treatment of the disease. U. Korkmaz (*) :A. E. Duman :G. Dindar :H. Yilmaz : A. Celebi :O. Senturk : S. Hulagu Department of Gastroenterology, Kocaeli University Medical Faculty, Umuttepe, 41900 Kocaeli, Turkey e-mail: [email protected]
The Turkish journal of gastroenterology | 2018
Ali Erkan Duman; Sadettin Hulagu; Altay Celebi; Uğur Korkmaz; Mahmut Mert Musul; Omer Senturk; Goktug Sirin; Hasan Yilmaz; Koç Dö; Gökhan Dindar; murat öztürkler; Neslihan Bozkurt; Hale Maral Kir
BACKGROUND/AIMS Glycoprotein 2 (GP2), the major autoantigen of Crohns disease (CD)-specific pancreatic autoantibodies, is reportedly correlated with several characteristics of CD. We investigated this serological marker in Turkish patients with CD and assessed its utility in combination with anti-Saccharomyces cerevisiae antibodies (ASCAs) for differential diagnosis of CD. MATERIALS AND METHODS A total of 60 patients with CD, 62 patients with ulcerative colitis (UC), and 46 healthy controls with a definite diagnosis who were similar in age and sex were enrolled in the study conducted from November 2011 to October 2012. ASCA and anti-GP2 levels were measured using commercially available kits. RESULTS Anti-GP2 IgA and IgG levels were higher in patients with CD (25%) than in those with UC (5%) and controls (2%). The seroprevalence of anti-GP2 IgA was markedly higher than that of IgG in patients with CD in contrast to previous studies. The specificity and positive predictive value of seropositivity for both ASCA and anti-GP2 were 100%. ASCA IgA seropositivity was correlated with a complicated disease course and a history of surgery. There was no correlation between anti-GP2 seropositivity and disease location, disease behavior, or a history of surgery. CONCLUSION The combination of ASCA and anti-GP2 may enable differentiation of CD from UC. As ASCA seropositivity is associated with a more complicated disease course, patients seropositive for ASCA at the initial diagnosis should undergo more intense therapy.
World Journal of Gastroenterology | 2014
Gökhan Dindar; Yucel Ustundag; Tarkan Karakan
Self expanding metalic stent (SEMS) application can cause serious problems up to one third of the patients and some studies reported negative effect of SEMSs on survival in patients with malignancy. The SEMS type especially the rigid one like Wall-stent rather than more flexible type Ultraflex was also reported to have bad impact on the risk of perforation we believe that stent based management protocol for patients with non-perforating left sided obstructing colorectal cancer is a complex method that needs qualified medical and technical team.
Gastroenterology | 2011
Sadettin Hulagu; Omer Senturk; Altay Celebi; Goktug Sirin; Koç Dö; Neslihan Bozkurt; Uğur Korkmaz; Ali Erkan Duman; Gökhan Dindar
G A A b st ra ct s However the relations between chemoresistance, cytoskeleton and EMT are inevitable. In the present study, we investigated the effect of chemoresistance on cell motility, cytoskeleton, and EMT. METHODS: HT-29, a human colon cancer cell, was exposed to increasing doses of 5FU or oxaliplatin for 6 months to achieve resistance at clinically relevant doses. cDNA microarray analysis was performed for parent and resistant cells. Rates of proliferation and sensitivity to drugs were assessed using WST-1 Assay. Cell movement was analyzed by Timelapse imaging; the images were captured under an Axiovert 200M microscope (CarlZeiss) for eight hours at intervals of 15 min. For cytoskeleton study, morphologic and molecular changes investigated by immunofluorescence staining and PCR analyses. RESULTS; HT29 cells were finally resistant to 5FU (2μg/mL) and oxaliplatin (2μmol/L). cDNA microarray studies showed alteration of cytoskeletal gene expression (actin related genes including caldesmon were upregulated) and EMT-related genes (TGF-beta1, ZEB2, and Vimentin were upregulated and E-cadherin was downregulated) in both 5FU resistant cells and oxaliplatin resistant cells. The both resistant cells exhibited a decrease in cellular proliferation and EMTlike morphologic changes; spindle-cell shape, loss of polarity, intercellular separation, and pseudopodia formation. Time-lapse imaging showed random and accelerated cell motility. Immunofluorescence staining revealed that E-cadherin expression was decreased and caldesmon expression was enhanced. Caldesmon is reported to act as a potent repressor of cancer cell invasion, however in both resistant cells of this study, overexpressed caldesmon was not associated with F-actin and stress fiber was not developed, which was not typical EMT phenotype. Depletion of caldesmon with siRNA restored the chemoresistant cells to parental cell-like adherent epithelial shape. CONCLUSIONS: These results indicate that chemoresistant CRC developed altered cytoskeleton, accelerated cell motility and atypical EMT phenotype, and that caldesmon is involved in chemoresistance-related phenotypical changes, suggesting that the cytoskeleton related genes are potent molecular targets to chemoresistance and tumor invasion/metastasis.
The Turkish journal of gastroenterology | 2013
Sadettin Hulagu; Şentürk Ö; Uğur Korkmaz; Şirin G; Ali Erkan Duman; Gökhan Dindar; Altay Celebi; Koç Dö; Neslihan Bozkurt; Hasan Yilmaz; Yesim Gurbuz; Duman D; Tarçın O
Internal Medicine | 2012
Ugur Korkmaz; Ali Erkan Duman; Berra Gurkan; Goktug Sirin; Yildiray Topcu; Gökhan Dindar; Yesim Gurbuz; Omer Senturk
Biomedical Research-tokyo | 2018
Mesut Sezikli; Goktug Sirin; Züleyha Akkan Çetinkaya; Alpaslan Tanoglu; Fatih Güzelbulut; Fatih Bunul; Gökhan Dindar
Kocaeli Tıp Dergisi | 2017
Mesut Sezikli; Gökhan Dindar; Melis Bektaş
Endoskopi Gastrointestinal | 2017
Gökhan Dindar; Mesut Sezikli; Emre Dönmez