Person: KOÇ, MEHMET
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KOÇ
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MEHMET
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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 Open Access Night-time blood pressure load is associated with higher left ventricular mass index in renal transplant recipients(NATURE PUBLISHING GROUP, 2003-04) KOÇ, MEHMET; Toprak, A; Koc, M; Tezcan, H; Ozener, IC; Oktay, A; Akoglu, EThe absence of nocturnal fall in blood pressure (BP) is named as nondipper status, which has been shown to be an additional risk factor for the development of left ventricular hypertrophy and cardiovascular events in several high-risk groups. The aim of this study was to determine the influences of the nondipper status and nocturnal blood pressure loads on left ventricular mass index (LVMI) in renal transplant recipients. A total of 35 nondiabetic renal transplant recipients were included into the study. A 24-h ambulatory blood pressure monitoring (ABPM) was performed for all recipients. The nondipper status was defined as either an increase in night-time mean arterial pressure (MAP) or a decrease of no more than 10% of daytime MAP. LVMI was measured by using two-dimensional guided M-mode echocardiography. The night-time systolic blood pressure (SBP) load was defined as the percentage of the time, during which SBP exceeded 125 mmHg during night time. The nondipping was common among renal transplant recipients, of whom 60% were nondipper in our study. LVMI was significantly higher in the nondipper group vs the dipper group (133 +/- 35 g/m(2) VS 109 +/- 26 g/m(2), P= 0.04). A fall in MAP at night time was 14.5 +/- 4.3% in the dipper group, while it was 1.4 +/- 6.1% in the nondipper group (P< 0.001). On stepwise multiple regression analysis, night-time SBP load and haemoglobin were independent predictors of LVMI (R-2 = 0.53). In conclusion, nondipping is common after renal transplantation. Night-time SBP load and low haemoglobin are closely related to the increase in LVMI in renal transplant recipients. ABPM may be a more useful tool in optimizing treatment strategies to reduce cardiovascular events in renal transplant recipients.Publication Open Access The genetic architecture of membranous nephropathy and its potential to improve non-invasive diagnosis(NATURE PUBLISHING GROUP, 2020-12) ARIKAN, İZZET HAKKI; Xie, Jingyuan; Liu, Lili; Mladkova, Nikol; Li, Yifu; Ren, Hong; Wang, Weiming; Cui, Zhao; Lin, Li; Hu, Xiaofan; Yu, Xialian; Xu, Jing; Liu, Gang; Caliskan, Yasar; Sidore, Carlo; Balderes, Olivia; Rosen, Raphael J.; Bodria, Monica; Zanoni, Francesca; Zhang, Jun Y.; Krithivasan, Priya; Mehl, Karla; Marasa, Maddalena; Khan, Atlas; Ozay, Fatih; Canetta, Pietro A.; Bomback, Andrew S.; Appel, Gerald B.; Sanna-Cherchi, Simone; Sampson, Matthew G.; Mariani, Laura H.; Perkowska-Ptasinska, Agnieszka; Durlik, Magdalena; Mucha, Krzysztof; Moszczuk, Barbara; Foroncewicz, Bartosz; Paczek, Leszek; Habura, Ireneusz; Ars, Elisabet; Ballarin, Jose; Mani, Laila-Yasmin; Vogt, Bruno; Ozturk, Savas; Yildiz, Abdulmecit; Seyahi, Nurhan; Arikan, Hakki; Koc, Mehmet; Basturk, Taner; Karahan, Gonca; Akgul, Sebahat Usta; Sever, Mehmet Sukru; Zhang, Dan; Santoro, Domenico; Bonomini, Mario; Londrino, Francesco; Gesualdo, Loreto; Reiterova, Jana; Tesar, Vladimir; Izzi, Claudia; Savoldi, Silvana; Spotti, Donatella; Marcantoni, Carmelita; Messa, Piergiorgio; Galliani, Marco; Roccatello, Dario; Granata, Simona; Zaza, Gianluigi; Lugani, Francesca; Ghiggeri, GianMarco; Pisani, Isabella; Allegri, Landino; Sprangers, Ben; Park, Jin-Ho; Cho, BeLong; Kim, Yon Su; Kim, Dong Ki; Suzuki, Hitoshi; Amoroso, Antonio; Cattran, Daniel C.; Fervenza, Fernando C.; Pani, Antonello; Hamilton, Patrick; Harris, Shelly; Gupta, Sanjana; Cheshire, Chris; Dufek, Stephanie; Issler, Naomi; Pepper, Ruth J.; Connolly, John; Powis, Stephen; Bockenhauer, Detlef; Stanescu, Horia C.; Ashman, Neil; Loos, Ruth J. F.; Kenny, Eimear E.; Wuttke, Matthias; Eckardt, Kai-Uwe; Koettgen, Anna; Hofstra, Julia M.; Coenen, Marieke J. H.; Kiemeney, Lambertus A.; Akilesh, Shreeram; Kretzler, Matthias; Beck, Lawrence H.; Stengel, Benedicte; Debiec, Hanna; Ronco, Pierre; Wetzels, Jack F. M.; Zoledziewska, Magdalena; Cucca, Francesco; Ionita-Laza, Iuliana; Lee, Hajeong; Hoxha, Elion; Stahl, Rolf A. K.; Brenchley, Paul; Scolari, Francesco; Zhao, Ming-hui; Gharavi, Ali G.; Kleta, Robert; Chen, Nan; Kiryluk, KrzysztofMembranous Nephropathy (MN) is a rare autoimmune cause of kidney failure. Here we report a genome-wide association study (GWAS) for primary MN in 3,782 cases and 9,038 controls of East Asian and European ancestries. We discover two previously unreported loci, NFKB1 (rs230540, OR = 1.25, P = 3.4 x 10(-12)) and IRF4 (rs9405192, OR = 1.29, P = 1.4 x 10(-14)), fine-map the PLA2R1 locus (rs17831251, OR = 2.25, P = 4.7 x 10(-103)) and report ancestry-specific effects of three classical HLA alleles: DRB1*1501 in East Asians (OR = 3.81, P = 2.0 x 10(-49)), DQA1*0501 in Europeans (OR = 2.88, P = 5.7 x 10(-93)), and DRB1*0301 in both ethnicities (OR = 3.50, P = 9.2 x 10(-23) and OR = 3.39, P = 5.2 x 10(-82), respectively). GWAS loci explain 32% of disease risk in East Asians and 25% in Europeans, and correctly re-classify 20-37% of the cases in validation cohorts that are antibody-negative by the serum anti-PLA2R ELISA diagnostic test. Our findings highlight an unusual genetic architecture of MN, with four loci and their interactions accounting for nearly one-third of the disease risk.Publication Open Access Effect of angiotensin-converting enzyme inhibition on endothelial function and insulin sensitivity in hypertensive patients(J R A A S LTD, 2003-06) YAVUZ, DİLEK; Tezcan, H; Yavuz, D; Toprak, A; Akpinar, I; Koc, M; Deyneli, O; Akalin, SIntroduction Evidence suggests an association between insulin resistance, hypertension and impaired endothelial function. Studies have shown that insulin resistance precedes the development of hypertension. By improving insulin sensitivity, it may be possible to improve hypertension and the subsequent damage to vessel walls. Some data indicates beneficial effects of angiotensin-converting enzyme (ACE) inhibitors on insulin sensitivity and endothelial function. We aimed to investigate these effects of ACE inhibition in the same group of patients with essential hypertension. Materials and methods Nine non-smoking, untreated hypertensive patients (38.3+/-9 years, 4/5 male/female) and 12 age-matched healthy subjects (35.2+/-6.7 years, 5/7 male/female) were included in the study. Hypertensive patients were given enalapril maleate (5-40 mg/day) for six months. The following parameters were studied at baseline and at the end of treatment period. Whole body insulin sensitivity was measured by a formula derived from an oral glucose tolerance test and named as the insulin sensitivity index (ISI). Insulin was measured by chemiluminescence and glucose by a glucose oxidase method. Endothelial function was evaluated as flow-mediated dilatation (FMD) of the brachial artery by ultrasonography and expressed as a percentage change relative to baseline diameter. Endothelial-independent vasodilatation was measured after sublingual nitroglycerine. Results FMD was impaired in the hypertensive group compared with healthy subjects (7.3+/-3.1% vs. 15.3+/-4.8%, p<0.0005), and ISI values were 1.18+/-0.6 vs. 4.4+/-0.9 (p<0.0001) respectively. Both insulin sensitivity and FMD improved after the treatment period compared with baseline values, FMD increased from 7.3+/-3.1% to 16.0+/-2.9% (p<0.0005) and ISI from 1.18+/-0.6 to 4.2+/-1.0 (p<0.0001). FMD and ISI showed a significant positive correlation (r=0.67, p<0.001) in the hypertensive group. Conclusions Patients with essential hypertension have impaired endothelial function and decreased whole body insulin sensitivity compared with healthy subjects. Treatment for six months with enalapril maleate seems to improve both FMD and ISI. This Study confirms the beneficial effects of ACE inhibition on both endothelial function and insulin sensitivity tested in the same group of essential hypertensive patients. The mechanism of these favourable effects of ACE inhibition needs to be clarified.Publication Metadata only Circulating endothelial cells as predictor of long-term mortality and adverse cardiovascular outcomes in hemodialysis patients(WILEY, 2021) KOÇ, MEHMET; Mohandas, Rajesh; Diao, Yanpeng; Chamarthi, Gajapathiraju; Krishnan, Suraj; Agrawal, Nikhil; Wen, Xuerong; Dass, Bhagwan; Shukla, Ashutosh M.; Gopal, Saraswathi; Koc, Mehmet; Segal, Mark S.Circulating endothelial cells (CEC) are thought to be markers of endothelial injury. We hypothesized that the numbers of CEC may provide a novel means for predicting long-term survival and cardiovascular events in hemodialysis patients. 54 hemodialysis patients underwent enumeration of their CEC number. We retrospectively analyzed their survival and incidence of adverse cardiovascular events. 22 deaths (41%) were noted over the median follow up period of 3.56 years (IQR 1.43-12) and 6 were attributed to cardiovascular deaths (11%) of which 1 (4%) was in the low CEC (CEC<20 cells/ml) and 5 (19%) in the high CEC (CEC >= 20 cells/ml) group. High CEC was associated with worse cardiovascular survival (p = 0.05) and adverse cardiac events (p = 0.01). In multivariate analysis, CEC >20 cells/ml was associated with a 4-fold increased risk of adverse cardiac events (OR, 4.16 [95% CI,1.38-12.54],p = 0.01) while all-cause mortality and cardiovascular mortality were not statistically different. In this hemodialysis population, a single measurement of CEC was a strong predictor of long term future adverse cardiovascular events. We propose that CEC may be a novel biomarker for assessing cardiovascular risk in dialysis patients.Publication Metadata only Streptococcus bovis bacteremia related to colon adenoma in a chronic hemodialysis patient(WILEY-BLACKWELL PUBLISHING, INC, 2010) VELİOĞLU, ARZU; Kahveci, Arzu; Ari, Elif; Arikan, Hakki; Koc, Mehmet; Tuglular, Serhan; Ozener, CetinWe report the case of a 54-year-old hemodialysis patient who presented with recurrent fever due to Streptococcus bovis bacteremia related to colonic tubulovillous adenoma. Following polypectomy and broad-spectrum antibiotic therapy, the patient totally recovered. In this paper, we discussed the relation between S. bovis bacteremia, colonic adenomas, and hemodialysis. Awareness of this association is critical for early diagnosis and management.