Person: KOÇ, MEHMET
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
KOÇ
First Name
MEHMET
Name
37 results
Search Results
Now showing 1 - 10 of 37
Publication Metadata only Histopathological changes and tumour necrosis factor-alpha, transforming growth factor-beta and tenascin expression in patients with primary type I membranoproliferative glomerulonephritis in remission(WILEY, 2009) ARIKAN, İZZET HAKKI; Arikan, Hakki; Koc, Mehmet; Cakalagaoglu, Fulya; Tuglular, Serhan; Ozener, Cetin; Akoglu, EmelAim: Primary type I membranoproliferative glomerulonephritis (MPGN) is a rare cause of glomerular disease with a high relapse rate and poor prognosis. The aim of this study was: (i) to evaluate the histopathological findings associated with remission; and (ii) to document the possible clinical and histopathological factors predicting relapses. Methods: Eleven type I MPGN patients (five men, six women; mean age, 38.8 +/-13.5 years) who were in remission for at least 1 year after the cessation of immunosuppressive drugs were re-biopsied. The intensity of immunostaining for tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta 1, and tenascin was graded from 0 (no staining) to 3+ (maximum staining). Results: Mean baseline mesangial cellularity score and tubulointerstitial infiltration score were reduced and mesangial matrix expansion score was increased at protocol re-biopsies compared to baseline. The glomerular and tubulointerstitial staining scores for TGF-beta 1 and tenascin were higher than that of baseline. Reduced tubulointerstitial TNF-alpha expression was found in re-biopsy specimens compared to baseline. Patients have been followed for a mean time of 51.5 +/- 22.2 months after the protocol biopsy. Eight patients had a relapse. Mesangial cellularity score and glomerular tenascin expression at re-biopsy specimens were higher in relapsed patients compared to those without a relapse. Conclusion: Our study shows that mesangial cellularity and tubulointerstitial cell infiltration are reducing whereas mesangial matrix expansion, glomerular and tubulointerstitial TGF-beta 1 and tenascin expression are increasing with remission. The higher mesangial cell proliferation and glomerular tenascin scores in remission are associated with the development of relapse.Publication Metadata only Statin use is associated with lower inflammation and erythropoietin responsiveness index in hemodialysis patients(WILEY, 2011) KOÇ, MEHMET; Koc, Mehmet; Dogan, Cengiz; Arinsoy, Turgay; Tonbul, Zeki; Ayli, Deniz; Cirit, Mustafa; Sever, Mehmet Sukru; Yilmaz, Mehmet Emin; Unsal, Abdulkadir; Suleymanlar, Gultekin; Ok, Ercan; Basci, Ali; Yildiz, AlaatinPatients with end-stage renal disease are prone to inflammation and inflammation is related to erythropoietin-stimulating agent hyporesponsiveness and mortality in this population. Statins have been demonstrated to reduce cardiovascular mortality in selected populations of end-stage renal disease patients. These drugs have pleiotrophic effects such as anti-inflammation. In this retrospective analysis, we determined whether the use of statins improves inflammation and inflammation-related anemia in a cohort of hemodialysis patients. Data were analyzed from Fresenius Medical Care Dialysis Clinics in Turkey between 2005 and 2007. Seventy prevalent hemodialysis patients who were on statins at the start of the study and have been on statins during follow-up (statin users) and 1293 patients who were not on statin at the start of the study and had never been prescribed any lipid-modifying drugs during follow-up (statin nonusers) were included in the study. High-sensitive C-reactive protein levels were significantly decreased in statin users (1.50 +/- 1.49 vs. 1.33 +/- 1.11 mg/L, P=0.05) compared with nonusers (1.93 +/- 3.22 vs. 2.05 +/- 2.77 mg/L). Hemoglobin levels and the rate of erythropoietin-stimulating agent users were similar. However, the prescribed erythropoietin-stimulating agent dose (31.6 +/- 27.5 vs. 47.3 +/- 45.2 U/kg/week, P < 0.05) and the erythropoietin response index (2.90 +/- 2.73 vs. 4.51 +/- 4.48 U/kg/week/Hb, P=0.001) were lower in statin users compared with statin nonusers. On stepwise multiple regression analysis, gender, high-sensitive C-reactive protein, duration of hemodialysis, serum ferritin, and statin use were independent determinants of the erythropoietin responsiveness index. Our results suggest that statin treatment leads to lower inflammation and improves hematopoiesis in hemodialysis patients.Publication Metadata only Effect of low- and high-dose levothyroxine on thyroid nodule volume: a crossover placebo-controlled trial(BLACKWELL PUBLISHING LTD, 2002) YAVUZ, DİLEK; Koc, M; Ersoz, HO; Akpinar, I; Gogas-Yavuz, D; Deynell, O; Akalin, SOBJECTIVE The efficacy and the effective dose of levothyroxine suppressive therapy in the treatment of benign thyroid nodules are controversial. In this study, we aimed to determine the response of solitary thyroid nodules to low- or high-level TSH suppression in a placebo-controlled, randomized crossover trial. DESIGN Forty-nine patients with solitary thyroid nodules on palpation were randomized to high-level and low- level TSH suppression groups. In each group, patients were further randomized to placebo and active levothyroxine subgroups. Patients in each subgroup were crossed over to placebo or active levothyroxine at the end of the first year and were then followed up for an additional year. METHODS TSH levels were suppressed to 0.4-0.6 mIU/ml and less than or equal to0.01 mIU/ ml in the low-level and high-level TSH suppression groups, respectively. Nodule volumes were measured at baseline and every 6 months after the desired level of TSH was reached if the patients were in the active levothyroxine treatment group or every 6 months if they were in the placebo group. RESULTS In high-level TSH suppression groups, nodule volume decreased significantly at the end of the active treatment periods (4.99 +/- 2.02 ml vs. 3.20 +/- 1.50 ml, P < 0.01, in Group 1; and 3.72 &PLUSMN; 1.79 ml to 2.05 &PLUSMN; 0.64 ml, P < 0.001, in Group 2). In the low-level TSH suppression groups, nodule volume also decreased significantly at the end of the active treatment periods (4.43 +/- 1.76 ml vs. 3.04 +/- 1.32, P < 0.05, in Group 3; and 3.59 &PLUSMN; 0.89 ml to 2.22 &PLUSMN; 0.59 ml, P < 0.01, in Group 4). Nodule volumes regained their original volumes during the placebo treatment periods. The percentage decline in clinically relevant nodule volume reduction (greater than or equal to50%) was similar in the low- level and high-level TSH suppression groups. CONCLUSION Low- and high-level TSH suppression were equally effective in reducing nodule volume and thus, considering the complications of high-level TSH suppression, low- level TSH suppression should be used if one considers levothyroxine suppressive therapy to reduce thyroid nodule size.Publication Metadata only Waist circumference is associated with carotid intima media thickness in peritoneal dialysis patients(SPRINGER, 2013) VELİOĞLU, ARZU; Asicioglu, Ebru; Kahveci, Arzu; Arikan, Hakki; Koc, Mehmet; Tuglular, Serhan; Ozener, Cetin IshakAtherosclerosis is responsible for the high mortality rate in end-stage renal disease patients. Defining risk factors for atherosclerosis may lead to reduction in cardiovascular disease through modification of these factors. Peritoneal dialysis (PD) patients are subjected to high glucose loads on a daily basis, which results in considerable weight gain and an increase in waist circumference (WC). WC as an indicator of abdominal obesity is a risk factor for atherosclerosis in the general population. Carotid artery intima media thickness (CIMT) measurement is a reliable method for the detection of early atherosclerosis. The aim of this study was to investigate the relationship between WC and CIMT and to define risk factors associated with CIMT in PD patients. Fifty-five PD patients and 40 healthy controls were included. Atherosclerosis was assessed using measurement of CIMT. Fasting blood was collected for analysis. Anthropometric parameters (age, weight, BMI, and WC) were measured. Peritoneal dialysis patients had higher WC (93.9 +/- A 1.7 vs. 87.3 +/- A 1.2 cm, p < 0.05) and CIMT (0.70 +/- A 0.02 vs. 0.57 +/- A 0.01 mm, p < 0.01) than the control group. On univariate analysis, age, WC, plaque formation, and D/P creatinine were positively correlated with CIMT, whereas residual renal function, albumin, ultrafiltration volume, and D/D0 glucose were negatively correlated. On multivariate analysis, only age, WC, and plaque formation showed correlation (p < 0.001). Carotid artery intima media thickness is associated with age, plaque formation, and WC in PD patients. WC measurement is a simple, inexpensive, reproducible, and reliable method of evaluating atherosclerosis risk in PD patients and should be assessed at every visit. Appropriate counsel should be provided to patients with greater WC who are deemed to be at risk for atherosclerosis.Publication Metadata only Elevated Plasma Levels of PAI-1 Predict Cardiovascular Events and Cardiovascular Mortality in Prevalent Peritoneal Dialysis Patients(TAYLOR & FRANCIS LTD, 2009) ARIKAN, İZZET HAKKI; Arikan, Hakki; Koc, Mehmet; Tuglular, Serhan; Ozener, Cetin; Akoglu, EmelBackground. Elevated plasminogen activator inhibitor-1 (PAI-1) levels are associated with increased cardiovascular (CV) risk in the general population. It has been shown that peritoneal dialysis (PD) patients have increased plasma levels of PAI-1. The aim of this study was to investigate whether PAI-1 independently predicted CV outcome in PD patients. Material and Methods. Seventy-two PD patients (53% females, mean age 49.9 +/- 16.1 years) were studied. Twelve patients who underwent kidney transplantation and 14 patients who transferred to hemodialysis during follow-up were excluded from the analysis. The remaining 46 patients (54% female, mean age 54 +/- 16 years, dialytic age 42 +/- 30 months) were followed a mean time of 45.4 +/- 19.4 months (range 8-71 months). Baseline PAI-1, clinical, and laboratory parameters were assessed in all patients. Survival analyses were made with Kaplan-Meier and Cox regression analysis, with all-cause mortality and CV mortality and CV events (CVEs) as clinical end points. Results. During the follow-up, 29 patients died (17 from CV causes), and 28 fatal and non-fatal CVEs were recorded. The patients were divided according to plasma PAI-1 levels (i.e., <= or >41 ng/mL). The significant independent predictors of all-cause of mortality were age (>60 years; p = 0.018), CRP (>5 mg/L; p = 0.015), and serum albumin (<3.5 g/L; p = 0.011). Multivariable Cox regression analysis showed that plasma PAI-1 >41 ng/mL was independently predictive of higher CV mortality (p = 0.021) and CVEs (p = 0.001). The only other independent predictor of CV mortality was only CRP (>5 mg/L; p = 0.008). Conclusions. Plasma levels of PAI-1 >41 ng/mL is a significant predictor of CV mortality and CVEs in PD patients.Publication Metadata only Baseline carotid intima-media thickness is associated with cardiovascular morbidity and mortality in peritoneal dialysis patients(WILEY, 2021) VELİOĞLU, ARZU; Asicioglu, Ebru; Velioglu, Arzu; Arikan, Hakki; Koc, Mehmet; Tuglular, Serhan; Ozener, CetinCarotid intima-media thickness (CIMT) is an early marker of atherosclerosis and is increased in peritoneal dialysis (PD) patients. Association of CIMT with cardiovascular disease (CVD) or mortality is less clear. Fibroblast growth factor-23 (FGF-23) is a hormone associated with vascular calcification, atherosclerosis, and mortality in the hemodialysis population. We investigated whether baseline CIMT and FGF-23 are associated with CVD and mortality in PD patients. Fifty-five PD patients were included. CVD was defined as ischemic heart disease, stroke, or peripheral artery disease. Intact FGF-23 was measured in plasma. CIMT was measured by ultrasonography. Twenty-one patients developed CVD and 12 died over 47.1 +/- 33.8 months. Patients with CVD were older (55.9 +/- 10.5 vs. 42.5 +/- 12.9 years, P < .01), had lower albumin (3.8 +/- 0.5 vs. 4.2 +/- 0.3 g/dL, P < .01) and higher CIMT (0.87 +/- 0.22 vs. 0.61 +/- 0.11 mm, P < .01). Patients with mortality were also older (53.5 +/- 11.5 vs. 45.8 +/- 13.8 years, P = .05), had lower albumin (3.7 +/- 0.6 vs. 4.1 +/- 0.3 g/dL, P < .01), higher CRP (15.0 +/- 8.5 vs. 7.6 +/- 8.4 mg/L, P < .01) and CIMT (0.9 +/- 0.3 vs. 0.6 +/- 0.1 mm, P < .01). Albumin and CIMT were associated with CVD and CIMT > 0.75 mm was associated with cardiovascular mortality. FGF-23 did not show any correlations. CIMT at baseline is associated with CVD and mortality in PD patients.Publication Metadata only Obestatin improves ischemia/reperfusion-induced renal injury in rats via its antioxidant and anti-apoptotic effects: Role of the nitric oxide(ELSEVIER SCIENCE INC, 2014) YEGEN, BERRAK; Koc, Mehmet; Kumral, Zarife Nigar Ozdemir; Ozkan, Naziye; Memi, Gulsun; Kacar, Omer; Bilsel, Serpil; Cetinel, Sule; Yegen, Berrak C.Obestatin was shown to have anti-inflammatory effects in several inflammatory models. To elucidate the potential renoprotective effects of obestatin, renal I/R injury was induced in male Sprague Dawley rats by placing a clamp across left renal artery for 60 min following a right nephrectomy. Clamp was released and the rats were injected with either saline or obestatin (10, 30, 100 mu g/kg). In some experiments, obestatin (10 mu g/kg) was administered with L-NAME (10 mg/kg) or L-Nil (0.36 mg/kg). Following a 24-h reperfusion, the rats were decapitated to measure serum creatinine and nitrite/nitrate levels, renal malondialdehyde (MDA), glutathione (GSH) levels and myeloperoxidase (MPO) activity and to assess cortical necrosis and apoptosis scores. Obestatin treatment reduced I/R-induced increase in creatinine levels, renal MPO activity and renal MDA levels, while renal GSH levels were significantly increased by obestatin. Histological analysis revealed that severe I/R injury and high apoptosis score in the kidney samples of saline-treated rats were significantly reduced and the cortical/medullary injury was ameliorated by obestatin. Expression of eNOS, which was increased by I/R injury, was further increased by obestatin, while serum NO levels were significantly decreased. iNOS inhibitor L-Nil reduced oxidative renal damage and improved the functional and histopathological parameters. I/R-induced elevation in eNOS expression, which was further increased by obestatin, was depressed by L-NAME and L-Nil treatments. The present data demonstrate that obestatin ameliorates renal I/R-injury by its possible anti-oxidative, anti-inflammatory and anti-apoptotic properties, which appear to involve the suppression of neutrophil accumulation and modulation of NO metabolism. (C) 2014 Elsevier Inc. All rights reserved.Publication Metadata only Experience with Treatment of Retroperitoneal Fibrosis: Collaboration of Urology and Nephrology Departments for 26 years in Marmara University(TURK NEFROLOJI DIYALIZ TRANSPLANTASYON DERGISI, 2017) ŞEKERCİ, ÇAĞRI AKIN; Sekerci, Cagri Akin; Tanidir, Yiloren; Ozgen, Mahir Bulent; Koc, Mehmet; Akbal, Cem; Simsek, FerruhOBJECTIVE: Retroperitoneal fibrosis (RPF) is a rare condition characterized by the presence of inflammation and fibrosis in the retroperitoneum. This study describes our multidisciplinary approach and our results. MATERIAL and METHODS: Patients diagnosed with RPF at Marmara University between January 1990 and May 2007 were evaluated. Etiologies, demographic characteristics, renal functions, treatments and prognoses of each patient were recorded and data were analyzed. RESULTS: Of all patients, five were female, 15 were male and the mean follow-up was 11.3 years (1-18 years). Six patients were operated unilaterally and five were operated bilaterally with ureterolysis. Median creatinine values at diagnosis were 2.75 mg/dl (0.7-6.9 mg/dl) in females, 3.2 mg/dl (0.84-7.2 mg/dl) in males and 3.11 mg/dl (0.7-7.2 mg/dl) in the whole group. Median baseline creatinine level after surgery (n=11) was found to decrease from 3.63 mg/dl (1.4-7.2 mg/dl to 1.46 mg/dl (0.8-2.6 mg/dl). Baseline and drop in creatinine were compared among patients treated with either surgical or pharmacological methods, and no statistical significance was found. CONCLUSION: Retroperitoneal fibrosis can be treated surgically and pharmacologically. Our study has shown similar success for both methods. Treatment should be specific for each patient in a multidisciplinary fashion.Publication Metadata only Demographic and clinical characteristics of primary glomerular diseases in Turkey(SPRINGER, 2014) KOÇ, MEHMET; Ozturk, Savas; Sumnu, Abdullah; Seyahi, Nurhan; Gullulu, Mustafa; Sipahioglu, Murat; Artan, Serra; Bicik, Zerrin; Kutlay, Sim; Keles, Mustafa; Oygar, Deren; Odabas, Ali Riza; Kayatas, Mansur; Dursun, Belda; Sayarlioglu, Hayriye; Trablus, Sinan; Taymez, Dilek Guven; Ozdemir, Ali Abbas; Sahin, Gulizar Manga; Altun, Bulent; Azak, Alper; Altintepe, Lutfullah; Suleymanlar, Gultekin; Koc, Mehmet; Selcuk, Yilmaz; Kazancioglu, Rumeyza; Erkoc, Reha; Gursu, Meltem; Kucuk, Mehmet; Akcaoglu, Selma Alagoz; Yildiz, Abdulmecid; Unal, Aydin; Akarsu, Ozger; Ates, Kenan; Cankaya, Erdem; Turkmen, AydinThe aim of our study was to delineate the demographic and clinical properties of primary glomerular diseases of adult population in our country in the light of global knowledge. All over the country, a total of 25 centers entered data between May 2009 and July 2012 to the database created by 'Glomerulonephritis Study Group' of Turkish Society of Nephrology. Demographic and clinical characteristics, specific diagnoses of glomerular diseases and biopsy findings recorded to the database were analyzed. Among the 1,274 patients, who had renal biopsy within the defined time period, 55 % were male and 45 % were female. The mean age was 40.8 +/- A 14.6 years. The most frequent indication for biopsy was nephrotic syndrome (57.8 %), followed by nephritic syndrome including rapidly progressive glomerulonephritis (16.6 %) and asymptomatic urinary abnormalities (10.8 %). The most frequent primary glomerular disease was membranous nephropathy (28.8 %), followed by focal segmental glomerulosclerosis (19.3 %) and IgA nephropathy (17.2 %). The presented study displayed important data about the epidemiology of primary glomerular diseases among adults in our country. The predominance of membranous nephropathy in contrast to other countries, in which the most frequent etiology is IgA nephropathy, seems to be due to differences in the indications for renal biopsy.Publication Metadata only Peri̇ton di̇yali̇zi̇ hastasında leclerci̇a adecarboksi̇lata peri̇toni̇ti̇(2015-10-21) BARUTÇU ATAŞ, DİLEK; VELİOĞLU, ARZU; ARIKAN, İZZET HAKKI; KOÇ, MEHMET; TUĞLULAR, ZÜBEYDE SERHAN; AŞICIOĞLU, EBRU; BARUTÇU ATAŞ D., VELİOĞLU A., AŞICIOĞLU E., AYKENT M. B., ARIKAN İ. H., KOÇ M., TUĞLULAR Z. S., ÖZENER İ. Ç.Giriş: Peritonit, sürekli ayaktan periton diyalizinin (SAPD) en sık ve önemli komplikasyonudur. Leclercia adecarboksilata, Enterobactericea ailesinden gram negatif, hareketli bir basildir. Periton diyalizi (PD) ilişkili peritonitin çok nadir bir sebebidir. Olgu Sunumu: Kronik glomerulonefrite bağlı son dönem böbrek yetmezliği (SDBY) nedeniyle 12 yıldır SAPD tedavisi gören 72 yaşında kadın hasta ateş, bulantı, kusma, karın ağrısı ve diyalizatta bulanıklaşma şikayeti ile hastaneye başvurdu. Fizik muayenede kan basıncı 90/60 mm/Hg, ateş 38,8 C°, batında yaygın hassasiyet saptandı. Diyaliz sıvısında silme lökosit izlendi. Laboratuvar tetkiklerinde WBC 4.600/µL, CRP 135 mg/L (N: 0-5) ve prokalsitonin 63 ng/mL (N: 0-0.5) izlendi. Kan ve periton sıvısı kültürleri alındıktan sonra ampirik olarak intraperitoneal sefuroksim ve oral siprofloksasin başlandı. Ertesi gün hastada klinik kötüleşme oldu ve periton sıvısı kültüründe Acinetobacter Baumanii ve Leclercia Adecarboksilata üremesi bildirildi. Antibiyograma göre tedaviye intravenöz imipenem ile devam edildi. Klinik düzelme sağlandı, Diyalizat hücre sayısı tedavinin 5. gününde negatifleşti. 2 hafta sonra antibiyotik rezistansını önlemek için imipenem kesilerek intraperitoneal amikasin ve oral siprofloksasine geçildi. Toplam üç hafta süren antibiyotik tedavisi sonrası hasta tamamen iyileşti ve tekrarlayan kültürlerde üreme olmadı. PD katateri çekilmeyen hastanın takiplerinde relaps peritonit izlenmedi. Tartışma: Gram negatif mikroorganizmalarla ilişkili peritonitlerde mortalite daha yüksektir ve daha sık olarak PD kateterinin çıkarılması gerekmektedir. Leclercia Adecarboxilata tek başına ya da bizim hastamızda olduğu gibi polimikrobial infeksiyonların bir komponenti olarak izole edilebilir. Epidemiyolojisi tam olarak bilinmemekle birlikte hastaların çoğunluğu immunsupresiftir. Ancak Leclercia Adecarboksilatanın etken olduğu infeksiyonların çoğunluğu hayati tehdit oluşturmaz. Acinetobacter Baumanii gibi tehlikeli bir mikroorganizma ile birlikte üretilmesine rağmen uygun antibiyotik tedavisi ile başarılı bir sonuç alınmıştır.