İstanbul University-Cerrahpaşa
Recent publications
A fluorescent gold nanocluster was used for determining peroxyl radical scavenging activity of antioxidants. Histidine was used as a green reducing and protective agent, and glutathione (GSH) enhanced the fluorescence intensity of histidine-stabilized gold nanoclusters (AuNCs) by ligand exchange process. When AAPH-induced oxidation of GSH occurred, the initial fluorescence intensity of GSH-capped AuNCs (λex = 450 nm λem = 502 nm) was decreased with static quenching. The decline of fluorescence intensity of the GSH-capped AuNCs upon peroxyl radical attack is diminished with the addition of antioxidants to the reaction medium, the difference in fluorescence intensity being related to peroxyl radical scavenging activity of antioxidants. The 50 % inhibitive concentration of related antioxidant compounds were determined and compared to those of crocin bleaching assay. Inhibition % of sage (Salvia officinalis L.) and green tea (Camellia sinensis) infusions against peroxyl radicals were investigated. The proposed assay can be used for simple and selective estimation of the peroxyl radical scavenging activity in complex matrices, as histidine-stabilized GSH-capped AuNCs were selective toward peroxyl radicals, not affected by other ROS at the studied concentrations.
Colorectal cancer (CRC) is one of the leading causes of death and comprises a considerable percentage of cases presented with metastases. Herein, we report 81 yr-old female patient who was admitted to our clinic due to persistent nausea and vomiting. She had an eight years-history of colorectal cancer, and she had undergone a right hemicolectomy and received adjuvant capecitabine treatment. An incisional hernia was palpated around the umbilicus and confirmed by abdominal CT (computed tomography). Whole-body PET (positron emission tomography) revealed FDG (fluorodeoxyglucose)-enhanced lesions in the lungs, pancreas, and small bowel, suggesting metastases. Colonoscopy did not reveal any recurrence. Biopsies obtained from the pancreas with endosonography diagnosed colorectal cancer metastasis. During hospitalisation she has been operated due to ileus and the obstructed jejunal segment was resected. Histopathological examiation confirmed intestinal metastasis of the colorectal cancer. In conclusion, pancreas and small bowel metastases are both rare phenomena individually. Ileus caused by intestinal metastasis is also exceptional. The coexistence of these rare metastases and lung metastases in CRC can be related to the unique biologic behavior of this tumor.
Laryngeal tumours with multifactorial etiopathogenesis constitute similar to 1% of all body cancers. The imbalance between oxidative and antioxidative systems affects redox-homeostasis. The oxidative stress generated by the continuous formation of reactive oxygen species results in the oxidation of cellular molecules. The present study investigated the protein oxidation levels and the distribution of receptors for advanced glycation end products (RAGE) variants in the risk of laryngeal carcinoma (LC). RAGE gene polymorphisms were determined by restriction endonuclease-based assay in 120 controls and 120 LC patients. Spectrophotometric methods were used to determine oxidant and antioxidant parameters including protein-carbonyl-groups (PCO), advanced-oxidation-protein-products (AOPP), lipid-hydroperoxides (LPH), thiol-fractures, superoxide-dismutase (SOD) activity. The distributions of rs1800624 and rs2070600 genotypes differed non-significantly among the study groups, however, the rs2070600-Ser allele had a higher frequency among the patients. While rs1800624-A allele carriers had higher frequency of perineural and lymphatic invasion, rs2070600-Ser allele frequency was higher in advanced-stage patients and in patients with muscle and perineural invasion. PCO, AOPP, LPH levels, and SOD activity were significantly higher in the patients. According to AUCs all of them are of diagnostic importance, therefore, cut-off values were determined. The analysis of the combined effects of RAGE polymorphisms and the oxidative stress parameters showed that LPH, thiols, and SOD activity differ among RAGE variants. Our results suggest that high levels of serum PCO, AOPP, LPH, and SOD activity and rs2070600-Ser allele may have effects on LC risk individually and both polymorphisms of RAGE may affect the progression of the disease by interacting with the oxidant-antioxidant system.
Background: We aimed to evaluate the features of primary membranous nephropathy (MNP) in Turkish people. Methods: This is a retrospective analysis of patients with biopsy-proven primary MNP. We obtained the data collected between 2009 and 2019 in the primary glomerulonephritis registry of the Turkish Society of Nephrology Glomerular Diseases Study Group (TSN-GOLD). Patients with a secondary cause for MNP were excluded. Clinical, demographic, laboratory, and histopathological findings were analyzed. Results: A total of 995 patients with primary MNP were included in the analyses. Males constituted the majority (58.8%). The mean age was 48.4 ± 13.9 years. The most common presentation was the presence of nephrotic syndrome (81.7%) and sub nephrotic proteinuria (10.3%). Microscopic hematuria was detected in one-third of patients. The median estimated glomerular filtration rate (eGFR) was 100.6 mL/min/1.73 m2 (IQR, 75.4-116.3), and median proteinuria was 6000 mg/d (IQR, 3656-9457). Serum C3 and C4 complement levels were decreased in 3.7 and 1.7% of patients, respectively. Twenty-four (2.4%) patients had glomerular crescents in their kidney biopsy samples. Basal membrane thickening was detected in 93.8% of cases under light microscopy. Mesangial proliferation and interstitial inflammation were evident in 32.8 and 55.9% of the patients, respectively. The most commonly detected depositions were IgG (93%), C3 complement (68.8%), and kappa and lambda immunoglobulin light chains (70%). Although renal functions were normal at presentation, vascular, interstitial, and glomerular findings were more prominent on biopsy in hypertensive patients. No significant effect of BMI on biopsy findings was observed. Conclusions: Despite some atypical findings, the main features of primary MNP in Turkey were similar to the published literature. This is the largest MNP study to date conducted in Turkish people.
Background The use of more than one potentially lethal method together and sequentially to complete suicide is called “complex suicide.” Complex suicides are divided into two groups: planned and unplanned. This study aimed to discuss with literature 21 complex suicide cases identified after a 2-year retrospective study. Results This study included 21 complex suicide cases. Eleven were classified as planned complex suicides, and 10 were labeled as unplanned complex suicides. The average age of all cases was 42.5 ± 17.7 (min: 19, max: 76) years. Suicide notes were present in six (28.5%) cases. Fifteen victims (71.4%) suffered from psychiatric diseases. Twelve victims ingested a toxic dose of medication, nine cases jumped from a height, eight cases used stabbing, six cases used hanging, two cases ingested a corrosive substance, two cases drowned, two cases inhaled a toxic gas, one case ingested cyanide, one case ingested insecticide, and one case used suffocation with a plastic bag. In two cases, three methods of suicide were used together. In the current study, “corrosive substance intake + cyanide intoxication” and “corrosive substance intake + jumping from a height” were defined for the first time and have not been previously described in the literature. Conclusions Complex suicides are highly likely to be potentially mistaken for murder. The cause of death in these cases can be determined with a comprehensive autopsy along with a detailed examination of the scene, statements of relatives, and eyewitnesses.
This consensus statement by a panel of Fabry experts aimed to identify areas of consensus on conceptual, clinical and therapeutic aspects of Fabry disease (FD) and to provide guidance to healthcare providers on best practice in the management of pediatric and adult patients with FD. This consensus statement indicated the clinical heterogeneity of FD as well as a large number of pathogenic variants in the GLA gene, emphasizing a need for an individualized approach to patient care. The experts reached consensus on the critical role of a high index of suspicion in symptomatic patients and screening of certain at-risk groups to reveal timely and accurate diagnosis of FD along with an increased awareness of the treating physician about the different kinds of pathogenic variants and their clinical implications. The experts emphasized the crucial role of timely recognition of FD with minimal delay from symptom onset to definite diagnosis in better management of FD patients, given the likelihood of changing the disease’s natural history, improving the patients’ quality of life and the prognosis after enzyme replacement therapy (ERT) administered through a coordinated, multidisciplinary care approach. In this regard, this consensus document is expected to increase awareness among physicians about unique characteristics of FD to assist clinicians in recognizing FD with a well-established clinical suspicion consistent with pathogenic variants and gender-based heterogeneous clinical manifestations of FD and in translating this information into their clinical practice for best practice in the management of patients with FD.
The Global Campaign against Headache, as a collaborative activity with the World Health Organization (WHO), was formally launched in Copenhagen in March 2004. In the month it turns 18, we review its activities and achievements, from initial determination of its strategic objectives, through partnerships and project management, knowledge acquisition and awareness generation, to evidence-based proposals for change justified by cost-effectiveness analysis.
Background A previous European Headache Federation (EHF) guideline addressed the use of monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) pathway to prevent migraine. Since then, randomized controlled trials (RCTs) and real-world evidence have expanded the evidence and knowledge for those treatments. Therefore, the EHF panel decided to provide an updated guideline on the use of those treatments. Methods The guideline was developed following the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) approach. The working group identified relevant questions, performed a systematic review and an analysis of the literature, assessed the quality of the available evidence, and wrote recommendations. Where the GRADE approach was not applicable, expert opinion was provided. Results We found moderate to high quality of evidence to recommend eptinezumab, erenumab, fremanezumab, and galcanezumab in individuals with episodic and chronic migraine. For several important clinical questions, we found not enough evidence to provide evidence-based recommendations and guidance relied on experts’ opinion. Nevertheless, we provided updated suggestions regarding the long-term management of those treatments and their place with respect to the other migraine preventatives. Conclusion Monoclonal antibodies targeting the CGRP pathway are recommended for migraine prevention as they are effective and safe also in the long-term.
Background Heart rate, acidosis, consciousness, oxygenation, and respiratory rate (HACOR) have been used to predict noninvasive ventilation (NIV) failure. However, the HACOR score fails to consider baseline data. Here, we aimed to update the HACOR score to take into account baseline data and test its predictive power for NIV failure primarily after 1–2 h of NIV. Methods A multicenter prospective observational study was performed in 18 hospitals in China and Turkey. Patients who received NIV because of hypoxemic respiratory failure were enrolled. In Chongqing, China, 1451 patients were enrolled in the training cohort. Outside of Chongqing, another 728 patients were enrolled in the external validation cohort. Results Before NIV, the presence of pneumonia, cardiogenic pulmonary edema, pulmonary ARDS, immunosuppression, or septic shock and the SOFA score were strongly associated with NIV failure. These six variables as baseline data were added to the original HACOR score. The AUCs for predicting NIV failure were 0.85 (95% CI 0.84–0.87) and 0.78 (0.75–0.81) tested with the updated HACOR score assessed after 1–2 h of NIV in the training and validation cohorts, respectively. A higher AUC was observed when it was tested with the updated HACOR score compared to the original HACOR score in the training cohort (0.85 vs. 0.80, 0.86 vs. 0.81, and 0.85 vs. 0.82 after 1–2, 12, and 24 h of NIV, respectively; all p values < 0.01). Similar results were found in the validation cohort (0.78 vs. 0.71, 0.79 vs. 0.74, and 0.81 vs. 0.76, respectively; all p values < 0.01). When 7, 10.5, and 14 points of the updated HACOR score were used as cutoff values, the probability of NIV failure was 25%, 50%, and 75%, respectively. Among patients with updated HACOR scores of ≤ 7, 7.5–10.5, 11–14, and > 14 after 1–2 h of NIV, the rate of NIV failure was 12.4%, 38.2%, 67.1%, and 83.7%, respectively. Conclusions The updated HACOR score has high predictive power for NIV failure in patients with hypoxemic respiratory failure. It can be used to help in decision-making when NIV is used.
Introduction Genistein is a natural isoflavonoid and has several pharmacological effects, such as antioxidant, antitumor activity, and improvement of glucose metabolism. The safety of intestinal anastomosis after ischemia–reperfusion (I/R) injury is a critical issue for surgeons. This experimental study aimed to investigate the effects of genistein on anastomotic healing after intestinal I/R injury. Methods A total of 36 male Wistar Albino rats were divided into four groups: control, I/R, genistein, and genistein + I/R. The control group received segmental ileal resection and ileoileal anastomosis. The I/R group received resection + anastomosis after intestinal I/R. The genistein group was administered subcutaneous injection of 1 mg/kg genistein 12 h and 1 h before the procedure and received ileal resection + anastomosis. The genistein + I/R group received I/R + ileal resection + anastomosis after genistein injection. Anastomotic bursting pressure, hydroxyproline, superoxide dismutase, and glutathione peroxidase levels and histopathological wound healing scores of all rats were measured on postoperative day 5. Results The anastomotic bursting pressure was significantly higher in the genistein and genistein + I/R groups (P < 0.001). Genistein increased the hydroxyproline concentration and the superoxide dismutase and glutathione peroxidase levels in the intestinal anastomosis (P < 0.001). In histopathological assessment, the mean wound healing score was significantly higher in the genistein group than in the other groups (P < 0.001). Conclusions Genistein, with its anti-inflammatory and antioxidant properties, shows protective effects against increased oxidative stress after intestinal I/R injury and contributes positively to intestinal anastomotic healing.
Computational methods used for estimation the effects of dynamic loading on buildings need to be developed and updated to ensure structural safety. A computer program, YAY2020-Dynamic was developed using the Matlab interpreter to calculate the effect of dynamic forces on planar structures. The program successfully estimated the impact of dynamic forces on structures. The main feature of the program is that it uses mass and stiffness matrices with both diagonal and non-diagonal elements. Furthermore, the developed program uses 12 × 12 matrices in shear formulations to include moment and rotation effects perpendicular to the plane. These features were not used in the literature and have not been studied on high-rise buildings before. Modal analysis (Eigen analysis) and time history analysis (Newmark analysis) are performed in the program for dynamic analysis of high-rise buildings. A special formulation is used to include angular and rotation freedom parameters in the mass and stiffness matrices of plate elements. These matrices were presented for the first time in this study as 12 × 12 matrices with diagonal and non-diagonal elements. The core principle of the program is to make more realistic modeling by considering as many mechanisms as possible, instead of making assumptions and neglecting some parameters that limit representing real behavior. To determine the performance of the developed program, two buildings (a 10-story and a 20-story) were examined. According to the results, YAY2020-Dynamic determined that the examined building models were more rigid and had fewer deformations than the estimated by SAP2000. Therefore, the use of YAY2020-Dynamic in design stages can help determine the required member strengths more precisely and choose the proper building materials while considering the safety factors.
Current trends and future innovative issues focus on the development of smart multifunctional bio-nanostructures. In this study, novel maca extract-coated CuO nanoparticles (MaE-CuO NPs) were prepared using a green and facile sonication method. Multifunctional MaE-CuO NPs were characterized by different techniques, such as Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), High Resolution Transmission Electron Microscopy (HRTEM), Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) techniques. According to the results, we proved that the sonosynthesized MaE-CuO NPs had a uniform spherical shape with an average diameter range of ~ 10 nm, while the surface area was 344.645 m 2 /g. The preservative performance of the antimicrobial MaE-CuO NPs was investigated to evaluate the biological activity of the nanostructure against Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), Candida albicans (C. albicans), and Aspergillus brasiliensis (A. brasiliensis). Furthermore, the MaE-CuO NPs-based non-enzymatic electrochemical and smart-phone colorimetric biosensor detected dopamine in the concentration range from 0.625 to 5 µM with a high sensitivity of 667 µA μM − 1 cm − 2 and a low limit of detection (LOD) value of 16.9 nM. Consequently, we proved that the obtained nanoformulations are promising antimicrobials agents and colorimetric/electrochemical dual-mode biosensors.
As in the whole world, abandoned mining sites and their immediate surroundings stands as a major environmental problem in Turkey. This study aims to reveal the factors affecting the utilization opportunities of the wetlands and their immediate surroundings in the abandoned mining sites in Istanbul through a multidimensional approach. In the study, a 34-variable factor analysis was performed, and approximately 75% of the respondents’ opinions were explained with seven factors by taking 24 variables as a basis at the end of the reliability analysis. These factors are listed according to their significance level: (1) utilization for recreational purposes, (2) utilization for functional purposes, (3) management and operation, (4) utilization as water reserve areas, (5) utilization as disposal sites, (6) legal framework, principles, and procedures, and (7) contribution to employment and economy. Afterwards, the nonparametric Kruskal-Wallis H and Mann-Whitney U tests were used to investigate whether there was a statistically significant and important difference between the various socio-economic variables (gender, occupation, workplace and experience) of the groups identified within the scope of the questionnaire. According to these results, thanks to the interdisciplinary and multi-functional planning of these sites after mining activities and their correct and effective management, the local people will be ensured to benefit from these sites at the highest level and the ecological balance will be re-established. The previous economic and ecological value of the abandoned mining sites should at least be restored and/or developed further. There are various criteria and indicators for this. In order to carry out and follow up the works in these areas in a successful way without interruption, it is important that legal arrangements to be made include not only forest areas but also all areas that require nature restoration such as agriculture, industry, solid waste, mines and quarries. In this sense, it should be ensured that all relevant persons and institutions cooperate with each other. As a result, in terms of sustainable land use, this study revealed an approach regarding the correct and effective management of damaged areas remaining after mining and its importance.
A series of early Oligocene Paratethyan manganese deposits occur in the shallow-marine sediments of the Maikop Series that surround the present-day Caspian Sea and Black Sea basins. These deposits are located either in former shallow-water seaways between the anoxic basins, where they typically occur as world-class deposits, or as much smaller deposits in shallow-water, shelf settings around the margins of the anoxic basins. The host rocks of the deposits are similar and are composed mainly of laminated marls, clays, and carbonates. The major-oxide compositions of the Paratethyan manganese deposits are similar and reveal a distinctive enrichment in Mn, Ca, and P, relative to Post-Archaean Australian Shale (PAAS). In addition, compared to the PAAS, the deposits typically show a trace element enrichment of Co, Ni, As, Ba, Sr, and strong depletion of Nb, Ta, Cr, Zr, Th, and Hf, which can be attributed to their similar processes of formation. Detrital-sourced elements of the Paratethyan deposits such as Nb, Ta, Cr, Zr, Th, Ti, and Hf are characteristically extremely low relative to the PAAS and indicate syn-sedimentary Mn-oxide and -carbonate deposition under conditions of low detrital input. Furthermore, a PAAS normalized positive Eu anomaly typically present in most deposits together with high contents of Co, Ni, As, Ba, and Sr in ores indicates a hydrothermal contribution into the basins. Besides the introduction of dissolved Mn and associated elements from rivers, this study shows that these elements may have been also discharged into the Paratethyan basins along the basin-margin growth faults. According to the geological and geochemical findings, Mn deposition is likely to have occurred from oceanic upwelling currents during periods of the high sea-level stand with syn-genetic precipitation of Mn-oxides and carbonates close to paleohighs between the deep anoxic basins.
Purpose To compare macula vascular parameters in optical coherence tomography angiography (OCTA) of children with history of retinopathy of prematurity (ROP) who were treated with laser photocoagulation (LPC) or intravitreal Bevacizumab therapy. Methods Forty eyes of 28 ROP children treated with LPC and 36 eyes of 22 ROP children treated with intravitreal Bevacizumab and 40 eyes of 40 age-gender matched term children were included the study. Capillary plexus densities in macula, FAZ parameters, outer retina and choriocapillaris flow rates, and central foveal thickness were measured. Results Foveal superficial and deep capillary plexus densities were found significantly higher in LPC and intravitreal Bevacizumab injection (IBI) groups compared to control group. FAZ area was found significantly lower in LPC and IBI groups compared to control group (p ‹ 0.001). Higher foveal superficial capillary plexus density, higher central foveal thickness, and lower FAZ area were found to be associated with poorer visual acuity in correlation analysis (p ‹ 0.05). In IBI group, earlier anti-VEGF therapy was found to be associated with lower foveal superficial capillary plexus density. Conclusion Microvascular characteristics such as FAZ area and capillary plexus densities of macula are deteriorated in ROP. There is no significant difference between the treatment alternatives of ROP in terms of macular microvascular parameters.
Post modifications such as alloying element addition and/or heat treatment are applied to improve the magnetic properties of NdFeB permanent magnets. In this study, effects of external magnetic field and flash annealing at different temperatures (680 °C and 710 °C) and durations of 5 and 10 min on the magnetic properties of relatively high Nd content (37 wt.%) NdFeB magnet alloys were investigated. Melt spinning method was used in production of the NdFeB magnet alloys. Heat treatment was applied to various NdFeB magnet ribbons at 680 °C and 710 °C temperatures for 5 and 10 min by the flash annealing at heating and cooling rates of 300 K/s. In addition, before vibrating sample magnetometer tests, various samples were magnetized under an external magnetic field of 5 Tesla. After melt spinning, semi-amorphous structure was obtained and Nd2Fe14B hard and α-Fe soft magnetic phases were crystallized at nanoscale by flash annealing. These crystallizations formed between approximately 350 °C and 430 °C. After the flash annealing, residual amorphous structures were observed without complete crystallization. The highest remanence and coercivity were obtained in the sample flash annealed for 10 min at 710 °C, 57.64 emu/g and 10,419.07 Oe, respectively. The maximum energy product improved thanks to the high remanence and coercivity, important for the NdFeB magnets resulted in a high value of 87.79 kJ/m³ in the same sample. This flash annealing procedure provides a cost-effective and simple platform to improve the magnetic features of NdFeB magnets.
Since the first case of COVID‐19 was reported in December 2019, many studies have been carried out on artificial intelligence for the rapid diagnosis of the disease to support health services. Therefore, in this study, we present a powerful approach to detect COVID‐19 and COVID‐19 findings from computed tomography images using pre‐trained models using two different datasets. COVID‐19, influenza A (H1N1) pneumonia, bacterial pneumonia and healthy lung image classes were used in the first dataset. Consolidation, crazy‐paving pattern, ground‐glass opacity, ground‐glass opacity and consolidation, ground‐glass opacity and nodule classes were used in the second dataset. The study consists of four steps. In the first two steps, distinctive features were extracted from the final layers of the pre‐trained ShuffleNet, GoogLeNet and MobileNetV2 models trained with the datasets. In the next steps, the most relevant features were selected from the models using the Sine–Cosine optimization algorithm. Then, the hyperparameters of the Support Vector Machines were optimized with the Bayesian optimization algorithm and used to reclassify the feature subset that achieved the highest accuracy in the third step. The overall accuracy obtained for the first and second datasets is 99.46% and 99.82%, respectively. Finally, the performance of the results visualized with Occlusion Sensitivity Maps was compared with Gradient‐weighted class activation mapping. The approach proposed in this paper outperformed other methods in detecting COVID‐19 from multiclass viral pneumonia. Moreover, detecting the stages of COVID‐19 in the lungs was an innovative and successful approach.
Institution pages aggregate content on ResearchGate related to an institution. The members listed on this page have self-identified as being affiliated with this institution. Publications listed on this page were identified by our algorithms as relating to this institution. This page was not created or approved by the institution. If you represent an institution and have questions about these pages or wish to report inaccurate content, you can contact us here.
2,041 members
Deniz Palamar
  • Department of Physical Medicine and Rehabilitation
Nurten Kaya
  • Faculty of Health Sciences
Murat Uludag
  • Department of Physical Medicine and Rehabilitation
Matem Tunçdemir
  • Department of Medical Biology
Cenk Eray Yildiz
  • Institute of Cardiology
Information
Address
İstanbul University-Cerrahpaşa Rectorate, 34320, Istanbul, Turkey
Website
http://istanbulc.edu.tr/en