Person: YAVUZ, DİLEK
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YAVUZ
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DİLEK
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Publication Metadata only Does concomitant prolactin measurement increase the accuracy of inferior petrosal sinus sampling?(SPRINGER, 2022) YAVUZ, DİLEK; Apaydin, Tugce; Yasar, Mehmet; Baltacioglu, Feyyaz; Haklar, Goncagul; Yavuz, Dilek GogasIntroduction Prolactin (PRL) measurement during inferior petrosal sinus sampling (IPSS) can be helpful to improve the accuracy. We aimed to evaluate the effect of measuring PRL levels as a predictor for the accuracy of IPSS and evaluate its impact on the lateralization of adenomas. Methods In this retrospective cohort study, we reviewed 51 patients who had undergone IPSS for the investigation of ACTH-dependent hypercortisolism. Results Forty-nine patients had proven Cushing's disease (CD), one had EAS, and the remaining one patient had adrenal adenoma. Forty-seven patients had an above 2 ACTH IPS/P ratio at baseline, and all the post-corticotropin-releasing hormone (CRH) ACTH IPS/P ratios of patients with proven CD were above 3. In these two patients whose ACTH IPS/P ratio at baseline was below 2, PRL IPS/P ratios were above 1.8 in only the dominant side, which was considered secondary to a prolactin intersinus gradient due to the biological effects of the tumor. PRL-adjusted ACTH IPS/P ratios were > 1.3 in all patients with proven CD; it was 0.7 in the patient with EAS. Surgically confirmed positive lateralization was observed in 55.1% of patients with the ACTH gradient, but when PRL-adjusted ACTH IPS/IPS ratios were used in addition to the ACTH gradient, the ratio increased to 67.3%. Conclusion Although PRL-adjusted ACTH IPS/P ratios can be helpful to improve the accuracy of results during IPSS procedures, a prolactin intersinus gradient towards the ACTH-dominant side in patients with CD may invalidate PRL as an indicator of pituitary venous outflow.Publication Metadata only Serum osteoprotegerin levels, endothelial function and carotid intima-media thickness in type 2 diabetic patients(ELSEVIER SCIENCE INC, 2021) YAVUZ, DİLEK; Gunes, Mutlu; Temizkan, Sule; Apaydin, Tugce; Ilgin, Can; Haklar, Goncagul; Yavuz, Dilek GogasObjectives: Osteoprotegerin (OPG), a well-known protein that inhibits osteoclast formation and activity, might also be a potential marker for identifying patients with high cardiovascular risk. This study aimed to compare OPG levels, FMD, and CIMT measurements in subjects with vs. without diabetes and investigate the association of serum osteoprotegerin level with the early atherosclerotic markers, endothelial function, and carotid intimamedia thickness (CIMT) in patients with type 2 diabetes mellitus (DM2). Methods: Forty-nine patients with DM2 (F/M: 26/23, 49.3 +/- 10.0 years) and 45 healthy volunteers (F/M: 26/19, 48.3 +/- 7.5 years) were included in this cross-sectional study. Serum OPG levels were measured by solid-phase enzyme-linked immunosorbent assay (ELISA). Fasting plasma glucose (FPG) and HbA1c levels were measured. CIMT was measured by B-mode ultrasound, and endothelial function was evaluated via flow-mediated dilation (FMD) of the brachial artery with Doppler ultrasonography. Results: Serum OPG levels were significantly higher in patients with DM2 (617.0 +/- 111.0 pg/mL) compared to controls (481.0 +/- 96.0 pg/mL, p < 0.001). While CIMT in diabetic patients (0.65 + 0.13 mm) was higher than controls (0.54 +/- 0.10 mm, p = 0.009), FMD measurement was lower in DM2 group (4.2% +/- 3.1 mm vs. 7.6% +/- 4.1 mm, p = 0.01). Univariate analysis showed that OPG was associated with the presence of diabetes (OR: 6.999, p = 0.001, R-2: 15.1%) and hypertension (OR = 6.925, p = 0.001, R-2: 13.2%). There was no relationship between OPG levels and CIMT or FMD. Conclusion: Osteoprotegerin and CIMT levels were increased, and FMD measurements were decreased in patients with DM2. No association between CIMT, FMD, and OPG measurements was observed. The presence of DM and hypertension were associated with circulating OPG levels.Publication Metadata only Collagen ultrastructure and TGF-beta 1 expression preserved with aminoguanidine during wound healing in diabetic rats(TAYLOR & FRANCIS INC, 2005) YAVUZ, DİLEK; Yavuz, D; Tugtepe, H; Cetinel, S; Uyar, S; Kaya, H; Haklar, G; Civelek, S; Deyneli, O; San, T; Burcak, G; Akalin, SAdvanced glycoxidation end products have been implicated in delayed diabetic wound healing. In this study, we evaluated the effects of aminoguanidine, which is an advanced glycation and nitric oxide ( NO) synthase inhibitor, on extracellular matrix protein expression, collagen configuration, and nitrite/nitrate levels in wounds of diabetic rats. Sixteen Wistar male rats were made diabetic by streptozotocin. Of these, eight rats were given AG ( aminoguanidine bicarbonate ( AG) ( group DAG) in their drinking water, and eight rats were followed as diabetic paired controls ( group D). Eight healthy rats were followed as the healthy control group ( group H). At the eighth week, a 2 x 2 cm area full-thickness skin defect was created. The degree of contraction of the open wounds was evaluated for 2 weeks duration. On the 15th postoperative day, wound surface areas were measured, and wound specimens and blood samples were collected. The shrinking percentage of the wounds was small in both groups H and DAG compared with group D ( p < 0.05). Similar to healthy rats, the aminoguanidine-treated diabetic rats had very strong transforming growth factor ( TGF)-beta 1 expression in granulation tissue and intact skin in comparison with diabetic controls. In the diabetic group, the intact skin demonstrated sparsely distributed regular collagen fibers in the granulation zone, and the regular pattern of collagen fibers was lost. In conclusion, aminoguanidine improves wound healing, restores growth factor TGF-beta 1 expression, and preserves collagen ultra structure, whereas it has no prominent effect on NO levels within wound tissue in diabetic rats.Publication Metadata only Effects of captopril and losartan on lipid peroxidation, protein oxidation and nitric oxide release in diabetic rat kidney(2003) YAVUZ, DİLEK; Yavuz, Dilek; Küçükkaya, Belgin; Haklar, Goncagül; Ersöz, Onder; Akoğlu, Emel; Akalin, SemaIncreased oxidative stress has an important role in the pathogenesis of diabetic nephropathy. The aim of this study was to evaluate the effects of renin-anigiotensin system blockage, either by angiotensin-converting enzyme inhibition or angiotensin receptor blockage, on oxidative stress and nitric oxide release in diabetic rat kidneys. After induction of diabetes, six rats were given captopril, six rats were given losartan, and six rats served as diabetic controls. Six healthy rats were also included. At the end of an 8-week period nitric oxide release, lipid peroxidation and protein oxidation were measured in kidney cortices, and urinary albumin excretion (UAE) was determined in 24-h urine samples. Losartan- and captopril-treated diabetic rats had lower levels of UAE than diabetic controls. Diabetic rats had higher levels of lipid peroxidation and protein oxidation compared to healthy rats. NO release was significantly lower in diabetic groups than healthy controls. UAE levels showed a positive correlation with lipid peroxidation and a negative correlation with NO release. Inhibition of lipid peroxidation could be one of the protective mechanisms of renin-angiotensin axis inhibition in diabetic kidney tissues.Publication Metadata only Rosiglitazone attenuates liver inflammation in a rat model of nonalcoholic steatohepatitis(SPRINGER, 2007) ÇELİKEL, ÇİĞDEM; Tahan, Veysel; Eren, Fatih; Avsar, Erol; Yavuz, Dilek; Yuksel, Meral; Emekli, Ebru; Imeryuz, Nese; Celikel, Cigdem; Uzun, Hafize; Haklar, Goncagul; Tozun, NurdanRosiglitazone is an insulin-sensitizing agent. We aimed to assess the effects of rosiglitazone on a methionine- and choline-deficient diet (MCDD) model of nonalcoholic steatohepatitis (NASH) in rats. Wistar rats were fed either MCDD or a control diet in the 4-week induction study; they were given saline or 4 mg/kg/day rosiglitazone. After the induction study period, the rats were divided into four groups and fed MCDD or given a control diet for an additional 8 weeks and received saline or rosiglitazone. Serum and tissue samples were obtained. Rosiglitazone improved inflammation in NASH and improved ALT, alkaline phosphatase, and interleukin-6 levels in the induction study and interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha levels in the treatment study. Our preliminary study is the first to show the anti-inflammatory effects of rosiglitazone in NASH. Rosiglitazone's effect on cytokines may be a key mechanism of its anti-inflammatory effect in NASH.