WoS İndeksli Yayınlar Koleksiyonu

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2-[(2-Bromo-phen-yl)imino-meth-yl]-6-methyl-phenol
(int Union Crystallography, 2010) Karadag, Asli Tosyali; Atalay, Sehriman; Genc, Hasan
In the title compound, C14H12BrNO, is a Schiff base which adopts the phenol-imine tautomeric form in the solid state. The dihedral angle between the two aromatic rings is 34.26 (9)degrees and an intramolecular O-H center dot center dot center dot N hydrogen bond generates an S(6) ring.
2-[(E)-2-Hy-droxy-5-(trifluoro-meth-oxy)benzyl-idene-amino]-4-methyl-phenol
(int Union Crystallography, 2011) Karadag, Asli Tosyali; Atalay, Sehriman; Genc, Hasan
The title compound, C15H12F3NO3, is a Schiff base which adopts the cis-quinoid form in the solid state. The dihedral angle between the least-squares planes of the benzene rings being 3.6 (1)degrees. The F atoms of the -CF3 group are disordered over two sets of sites with refined occupancies of 0.61 (5) and 0.39 (5). An intramolecular N-H center dot center dot center dot O hydrogen bond occurs. The crystal structure is stabilized by intermolecular O-H center dot center dot center dot O hydrogen bonds.
2-Phenyl Substituted Benzimidazole Derivatives: Design, Synthesis, and Evaluation of Their Antiproliferative and Antimicrobial Activities
(Springer Birkhauser, 2022) Ersan, Ronak Haj; Kuzu, Burak; Yetkin, Derya; Alagoz, Mehmet Abdullah; Dogen, Aylin; Burmaoglu, Serdar; Algul, Oztekin
The inability to meet the desired outcomes of anticancer treatment and decrease in treatment success of bacterial and fungal infections accelerated research in these areas. Our research group has conducted numerous studies, especially on benzimidazole ring systems' antiproliferative and antimicrobial activities. In this study, the antiproliferative activity of benzimidazole compounds was tested against A549, A498, HeLa, A375, and HepG2 cancer cell lines by MTT assay. All compounds exhibited good to potent antiproliferative activity against all tested cancer cell lines. Compounds 6-chloro-2-(4-fluorobenzyl)-1H-benzo[d] imidazole (30) and 6-chloro-2-phenethyl-1H-benzo[d]imidazole (46) were especially active against HeLa and A375 cancer cell lines with IC50 values in the range of 0.02-0.04 mu M. In contrast, compounds 6-chloro-2-((p-tolyloxy)methyl)-1H-benzo[d] imidazole (67) and 5(6)-chloro-2-((4-hydroxyphenoxy)methyl)-1H-benzimidazole (68) were active against A549 and A498 cancer cell lines with an IC50 value of 0.08 mu M. These compounds (30, 46, 67, and 68) were less toxic to normal human cells than the positive control compound methotrexate, which was screened to determine its toxicity against normal cell lines (HEK293). In the second part of the study, all compounds were tested to demonstrate their antimicrobial properties. All compounds exhibited moderate activity against all tested bacteria and fungi. However, some phenoxy methyl derivatives 5-chloro-2-((4-chlorophenoxy)methyl)-1H-benzo[d]imidazole (69) and 5,6-dichloro-2-((4-chlorophenoxy)methyl)-1H-benzo[d] imidazole and (74) were most active against Candida (<3.90 mu g/mL). Molecular docking studies were carried out against certain proteins in order to identify potential targets of the antiproliferative effects of the synthesized compounds. The docking scores of the compounds were found to be significantly compatible with the antiproliferative activity results. [GRAPHICS] .
3,5-Dibenzoyl
(int Union Crystallography, 2009) Sahin, Zarife Sibel; Isik, Samil; Sener, Ahmet; Tan, Meltem
In the crystal structure of the title compound, C26H27NO3, a one-dimensional network of C-H center dot center dot center dot O hydrogen bonds and pi-ring interactions is responsible for crystal stabilization. Intermolecular hydrogen bonds and C-H center dot center dot center dot pi interactions produce R-2(2)(10), R-4(4)(27) and R-4(4)(29) rings.
3-Mcpd and Glycidol Levels in Edible Oils and Fats Obtained From Local Markets in Turkiye
(Consejo Superior investigaciones Cientificas-csic, 2023) Gunduz, A. O.; Ceylan, M. M.; Basturk, A.
In this study, it was aimed to determine the 3-MCPD and glycidol levels in 9 types (46 brands) of edible fat and oil offered for sale in markets located in Turkiye. 3-MCPD and glycidol levels were determined by making some modifications to the DGF C VI 18 (10) method. The highest levels of 3-MCPD and glycidol levels were detected in hazelnut oils, riviera olive oils, margarines, and shortenings. As expected, these contaminants were not observed in extra-virgin olive oils, while they were detected at low levels in fish oils. The highest 3-MCPD levels were found in the range of 0.06-2.12 mg & BULL;kg-1 in hazelnut oil, 0.16-1.69 mg & BULL;kg-1 in riviera olive oils, and 0.17-1.17 mg & BULL;kg-1 in margarines. The highest glycidol levels were found in the shortenings in the range of 1.98-6.46 mg & BULL;kg-1, followed by hazelnut oil (0.54-2.63 mg & BULL;kg-1) and riviera olive oil (0.19-3.53 mg & BULL;kg-1).
3.5 Ghz Radiofrequency Radiation May Affect Biomechanics of Bone and Muscle of Diabetics
(Taylor & Francis Ltd, 2023) Bektas, Hava; Dasdag, Suleyman; Nalbant, Asrin; Akdag, Mahmut Berat; Demir, Canan; Kavak, Servet
With the developments in wireless technologies, living beings are increasingly exposed to electromagnetic fields (EMFs). EMFs are known to affect bone metabolism and muscle tissue. However, their effects on bones and skeletal muscles are controversial, as some studies have reported positive effects while others have reported adverse effects. In this study, the effects of radiofrequency radiation (RFR) on bone biomechanics and skeletal muscle tissues were investigated in diabetic and healthy rats. Rats were exposed to 3.5 GHz RFR for 2 h per day for 30 days. Bone biomechanics measurements were taken to evaluate the effects of RFR on bone quality, flexibility and durability. The whole-body specific absorption rate (SAR) was found to be 37 mW/kg. The results showed that RFR exposure had adverse effects on bone biomechanics, including decreased elasticity coefficient and Young's modulus, increased maximum displacement and decreased maximum force. However, oxidative stress parameters in diabetics were also altered by 3.5 GHz RFR to a greater extent than in healthy rats. In conclusion, 3.5 GHz RFR may have potential to alter bone quality and structural integrity including muscle oxidative stress parameters in rats. It should be emphasized that the observed changes were more obvious in diabetic rats. In addition, the changes observed in healthy and diabetic rats exposed to RFR showed a statistically significant difference according to the sham groups.
3d Location Optimization of Multiple Unmanned Aerial Vehicle Base Stations in Next-Generation Cellular Networks and a New Meta-Heuristic Approach
(Gazi Univ, Fac Engineering Architecture, 2021) Ozdag, Recep
The use of Unmanned Aerial Vehicles (UAVs) as mobile Base Stations (BSs) in wireless communication is emerging as an effective technique that should be used for the services planned in the next-generation cellular networks or in disaster situations. Currently, effective 3D placement of BS mounted on UAVs or Drones (Drone-BS), also called Low-altitude Air Platforms, in the defined area significantly increases the Quality of Service (QoS) of wireless communication. This study has been aimed to be performed dynamic deployments (location optimization) of Drone-BSs randomly distributed in the 3D plane in order to optimally cover the users in the urban environment according to the Air-to-Ground (ATG) model. Using new approaches based on the Electromagnetism-Like (EML) Algorithm and the Whale Optimization Algorithm (WOA), which are widely used in the literature and are meta-heuristic, it was planned to be covered the maximum number of users on the ground by multiple Drone-BSs. In addition, Extensive-interval Optimal Fitness Search Algorithm (EOFSA-EML) and Discrete-interval Optimal Fitness Search Algorithm (DOFSA-EML) approaches were developed based on the EML algorithm. Based on comparison metrics for multiple Drone-BSs distributed by EOFSA-EML, DOFSA-EML, and Pure-WOA, it has been found that EML-based algorithms achieve optimal results compared to Pure-WOA.
A 5 Years Follow-Up for Ischemic Cardiac Outcomes in Patients With Carotid Artery Calcification on Panoramic Radiographs Confirmed by Doppler Ultrasonography in Turkish Population
(British inst Radiology, 2020) Akkemik, Ozlem; Kazaz, Hakki; Tamsel, Sadik; Dundar, Nesrin; Sahinalp, Sahin; Ellidokuz, Hulya
Objective: To evaluate the diagnostic accuracy of digital panoramic radiograph (DPR) for detection of carotid artery calcification (CAC) confirmed by Doppler Ultrasonography (DUSG) and to clarify the relationship between between CAC identified by DPR and cardiovascular events through a 5 year follow-up period. Methods: Of 3600 consecutive patients examined, 158 patients presented with CAC as detected by DPR. The final study group was composed of 96 patients who had CAC confirmed by DUSG or CT angiogram. The control group was composed of 62 patients who has normal DUSG. The end point of the study was the occurrence of any cardiovascular event. Results: 72 (75%) of the 96 patients with CAC confirmed by DUSG (16 patients had significant stenosis) had bilateral and 24 (25%) had unilateral CAS as detected by DUSG. There was a low agreement between the examination results with a kappa value of 0.488 (p < 0.005) for calcification. Study data revealed that smoking, chronic obstructive pulmonary disease (COPD), diabetes mellitus (DM) and diastolic hypertension were significantly more common in patients with CAC than the control group (p < 0.05). During the follow-up period, 13 subjects had myocardial infarction and 1 subject died; in the control group, 1 patient died after MI and 1 patient died of a non-cardiac event. Conclusion: Patients with CAC detectable by DPR concomitant with COPD, DM, smoking or diastolic hypertension are more likely to suffer from vascular events. Therefore, patients with detectable carotid plaque in DPR require referral to a cardiovascular surgery clinic for further investigations.
5-fluoro/(trifluoromethoxy)-2-indolinone Derivatives With Anti-Interleukin Activity
(Wiley-v C H verlag Gmbh, 2023) Soylu-Eter, Ozge; Sevincli, Zekiye Seyma; Ersoy, Betul; Hasanusta, Bahar; Gatfar, Ugur; Lack, Nathan A.; Karali, Nilgun
The pro-inflammatory cytokine interleukin-1 (IL-1) drives the pathogenesis of several inflammatory diseases. Recent studies have revealed that 2-indolinones can modulate cytokine responses. Therefore, we screened several 2-indolinone derivatives in preliminary studies to develop agents with anti-IL-1 activity. First, the putative efficacies and binding interactions of 2-indolinones were evaluated by docking studies. Second, previously synthesized 5-fluoro/(trifluoromethoxy)-1H-indole-2,3-dione 3-(4-phenylthiosemicarbazones) (compounds 47-69) which had the highest inhibitory effect in the screening were evaluated for inhibitory effects on the IL-1 receptor (IL-1R). Compounds 52 (IC50 = 0.09 mu M) and 65 (IC50 = 0.07 mu M) were selected as lead compounds for the subsequent synthesis of new derivatives. The novel 5-fluoro/(trifluoromethoxy)-1H-indole-2,3-dione 3-(4-phenylthiosemicarbazones) (compounds 70-116) were designed, synthesized, and in vitro studies were completed. The compounds 76, 78, 81, 91, 100, 105, and 107 tested showed nontoxic inhibitory effects on IL-1R-dependent responses in the range of 0.01-0.06 mu M and stronger than the lead compounds 52 and 65. In vitro and in silico findings showed that compounds 78 (IC50 = 0.01 mu M) and 81 (IC50 = 0.02 mu M) had the strongest IL-1R inhibitory effects and the most favorable drug-like properties. Molecular modeling studies of the compounds 78 and 81 were carried out to determine the possible binding interactions at the active site of the IL-1R. Novel 5-fluoro/(trifluoromethoxy)-2-indolinone derivatives were designed and synthesized based on in silico and preliminary in vitro test results from lead compounds. All compounds tested displayed nontoxic IL-1 receptor inhibitory effects at IC50 values in the range of 10 nM to 13 mu M, and seven compounds showed inhibitory responses stronger than the lead compounds at 0.01-0.06 mu M.image
500,000 Years of Environmental History in Eastern Anatolia: the Paleovan Drilling Project
(Copernicus Gesellschaft Mbh, 2012) Litt, Thomas; Anselmetti, Flavio; Baumgarten, Henrike; Beer, Juerg; Cagatay, Namik; Cukur, Deniz; Wonik, Thomas
International Continental Scientific Drilling Program (ICDP) drilled a complete succession of the lacustrine sediment sequence deposited during the last similar to 500,000 years in Lake Van, Eastern Anatolia (Turkey). Based on a detailed seismic site survey, two sites at a water depth of up to 360 m were drilled in summer 2010, and cores were retrieved from sub-lake-floor depths of 140 m (Northern Basin) and 220 m (Ahlat Ridge). To obtain a complete sedimentary section, the two sites were multiple-cored in order to investigate the paleoclimate history of a sensitive semi-arid region between the Black, Caspian, and Mediterranean seas. Further scientific goals of the PALEOVAN project are the reconstruction of earthquake activity, as well as the temporal, spatial, and compositional evolution of volcanism as reflected in the deposition of tephra layers. The sediments host organic matter from different sources and hence composition, which will be unravelled using biomarkers. Pathways for migration of continental and mantle-derived noble gases will be analyzed in pore waters. Preliminary 40Ar/39Ar single crystal dating of tephra layers and pollen analyses suggest that the Ahlat Ridge record encompasses more than half a million years of paleoclimate and volcanic/geodynamic history, providing the longest continental record in the entire Near East to date.
7-Acetoxyhorminone From Salvia Multicaulis Vahl. as Promising Inhibitor of 3-Hydroxy Coenzyme a (hmg-Coa) Reductase
(Mdpi, 2022) Yigitkan, Serkan; Ertas, Abdulselam; Salmas, Ramin Ekhteiari; Firat, Mehmet; Orhan, Ilkay Erdogan
3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase is a key enzyme involved in cholesterol biosynthesis and one of the most important targets for the treatment of hypercholesterolemia. A limited number of studies on the HMG-CoA reductase inhibitory potential of natural products are available. Thus, in the current study, we aimed to test the HMG-CoA reductase inhibitory capacity of extracts from the roots and aerial parts of Salvia multicaulis Vahl., through activity-guided isolation. Our findings revealed that the root extract prepared with dichloromethane-acetone (1:1) showed the highest inhibition (71.97 +/- 0.37%) at 100 mu g/mL. The extract was then initially fractionated by column chromatography and the obtained fractions were monitored by thin layer chromatography. Fractions which were similar to each other were combined and a total of 15 fractions were obtained. Further conventional chromatographic studies were carried out on the active fractions. Based on these fractions, 10 known compounds, comprising 9 terpenes and 1 steroid derivative in total, were isolated and their structures were verified by a combination of IT-TOF-MS, and 1D and 2D NMR techniques. According to the enzyme inhibition data of the identified compounds, 7-acetoxyhorminone exerted the highest inhibition (84.15 +/- 0.10%, IC50 = 63.6 +/- 1.21 mu g/mL). The molecular docking experiments on 7-acetoxyhorminone and horminone indicated that both compounds strongly bind to the active site of the enzyme.
8-Ohdg Levels in Patients With Allergic Rhiniti
(Yerkure Tanitim & Yayincilik Hizmetleri A S, 2011) Onbasi, Kevser; Noyan, Tevfik; Cebi, Aysegl; Kiroglu, Faruk
Objective: Respiratory allergies like allergic rhinitis and allergic asthma are more frequently observed worldwide. Chronic inflammation in the respiratory tract is observed in these diseases. Oxidative stress contributes to this inflammation in the respiratory airways. 8-OHdG is a marker of oxidative stress. The aim of our study was to investigate the 8-OHdG levels in patients with respiratory allergy. Material and Methods: 23 patients with allergy consisting of 11 men and 12 women and 23 healthy controls were enrolled to the study. Results: 8-OHdG levels were found to be higher in allergic patients in comparison to healthy controls but it was not statistically significant. Conclusion: The reason for not significantly high levels of 8-OHdG levels as a marker of oxidative stress in respiratory allergy may attribute to the factor that the inflammation in respiratory allergy is less intensive in comparison to the inflammation in atopic dermatitis.
Ab Initio Study of Li2cata2o7 Compound: Electronic and Optical Properties for Three Phases
(Tubitak Scientific & Technological Research Council Turkey, 2019) Aycibin, Murat
The Li2CaTa2O7 compound belongs to the Ruddlesden-Popper family of layered perovskites. First principle approximation was used to investigate the electronic band structure and optical properties of the compound for three phases. Independent of the studied compound's structural type, Li2CaTa2O7 has semiconductor behavior and direct transition. In addition, the forbidden energy band gap of the compound decreases with rising temperature, as expected. Furthermore, the 3d orbital of Ca contributes to the conduction band due to the crystal field effect. Moreover, the optical response of the chosen axes of the compound to incoming electromagnetic rays varies with phase transition.
Ab-Initio Calculations of Physical Properties of Alkali Chloride Xcl (X = K, Rb and Li) Under Pressure
(Elsevier, 2015) Erdinc, Bahattin; Secuk, Mehmet Nurullah; Aycibin, Murat; Gulebagan, Sinem Erden; Dogan, Emel Kilit; Akkus, Harun
Structural properties, electronic band structure, real and imaginary parts of complex dielectric function of alkali chloride XCl (K, Rb and Li) compounds were investigated under various pressures using first principles calculations. Moreover, Gibbs free energies were also calculated at those pressures. Calculated results of the Gibbs free energy show that LiCl does not show any structural phase transition. However, structural phase transitions of KCl and RbCl occur from NaCl (B1) to CsCl (B2) at 4.5 and 1.7 GPa pressures, respectively. The electronic band gaps under pressure were also calculated. The calculated physical properties of these compounds are compared with the previous theoretical and experimental results and a good agreement was observed. (c) 2015 The Authors. Published by Elsevier B. V. This is an open access article under the CC BY-NC-ND license.
Abnormal Left Ventricular Longitudinal Functional Reserve Assessed by Exercise Pulsed Wave Tissue Doppler Imaging in Patients With Subclinical Hypothyroidism
(Endocrine Soc, 2009) Akcakoyun, Mustafa; Kaya, Hasan; Kargin, Ramazan; Pala, Selcuk; Emiroglu, Yunus; Esen, Ozlem; Esen, Ali Metin
Background: Response of systolic and diastolic velocities of mitral annulus to exercise in patients with subclinical hypothyroidism (SCH) has not been explored previously. We sought to investigate whether SCH is associated with abnormal left ventricular (LV) longitudinal function reserve to exercise. Methods: Mitral annular systolic (S') and early diastolic (E') velocities were measured at rest and during supine bicycle exercise using tissue Doppler echocardiography (TDE) in 23 patients with newly diagnosed SCH and 25 controls. LV diastolic and systolic longitudinal function reserve indices were calculated. Results: There were no significant differences in mitral inflow velocities at rest between groups except for LV end-diastolic dimension and LV end-systolic dimension, which were higher in the control group. E' and S' at rest were also similar between the groups. However, S' (9.8 +/- 1.5 vs. 11.3 +/- 1.5 cm/sec at 25 W, P = 0.001; and 11.3 +/- 1.8 vs. 13.1 +/- 1.8 cm/sec at 50 W, P = 0.001) and E' (13.8 +/- 1.4 vs. 15.7 +/- 1.6 cm/sec at 25 W, P = 0.001; and 15.6 +/- 1.6 vs. 18.2 +/- 1.5 cm/sec at 50 W, P < 0.001) during exercise were significantly lower in patients with SCH. Longitudinal systolic and diastolic function reserve indices were significantly lower in patients with SCH (systolic index, 1.4 +/- 0.9 vs. 2.5 +/- 0.9 cm/sec at 25 W, P = 0.001; and 2.7 +/- 1.3 vs. 4.1 +/- 1.2 cm/sec at 50 W, P = 0.001; diastolic index, 2.3 +/- 1.3 vs. 3.6 +/- 1.5 cm/sec at 25 W, P = 0.003; and 3.9 +/- 1.6 vs. 5.9 +/- 1.3 cm/sec at 50 W, P < 0.001). Conclusion: Assessment of LV longitudinal functional reserve with exercise using TDE appears to be helpful in identifying early myocardial dysfunction in SCH. (J Clin Endocrinol Metab 94: 2979-2983, 2009)
Absence of Frontal Sinus in Turkish Individuals
(Yonsei University College of Medicine, 2003) Aydinlioǧlu, A.; Kavakli, A.; Erdem, S.
The frontal sinus has been used for personal identification since the early part of the 20th century as a result of its tremendous interindividual variation. The frontal sinus is present in approximately 90% of adults. However, some populations have a higher proportion of people without a frontal sinus. This study investigated the frequency of the absence of frontal sinuses in Turkish individuals. The present study was performed retrospectively on the CT scans of the paranasal sinuses in the axial and coronal planes from a series of 1200 cases. A bilateral absence and a unilateral absence of sinuses were found in 3.8% and 4.8% of cases, respectively. The clinical significance of the frontal sinuses and their absence are also discussed.
Absence of Right Superior Vena Cava and Aortic Annular Hypoplasia in a Patient With Turner's Syndrome
(Wiley, 2005) Kutay, V; Yakut, C
Cardiovascular abnormalities are frequently encountered in patients with Turner's syndrome. These include coarctation of the aorta, bicuspid aortic valve, aortic root dilatation, atrial and ventricular septal defects, but absence of the right superior vena cava (SVC) in visceroatrial situs solitus is extremely rare. We report absence of the right SVC and congenital aortic annular hypoplasia with bicuspid aortic valve stenosis in a patient with Turner's syndrome. Aortic root extension with prosthetic valve replacement was performed and absent right SVC, which was detected incidentally during operation, is confirmed by postoperative venous angiogram.
Absence of the Mecc Gene in Methicillin-Resistant Staphylococcus Aureus Isolated From Various Clinical Samples: the First Multi-Centered Study in Turkey
(Elsevier Science London, 2019) Cikman, Aytekin; Aydin, Merve; Gulhan, Baris; Karakecili, Faruk; Kurtoglu, Muhammet G.; Yuksekkaya, Serife; Ozekinci, Tuncer
Background: mecA is a predefined gene causing methicillin resistance in Staphylococcus aureus (S. aureus) isolates; however, it has been shown that some methicillin-resistant S. aureus (MRSA) strains do not carry this gene. Recently, in isolates found to be MRSA-positive but mecA-negative, a new resistance gene called mecC, which is a homolog of mecA, has been reported. This study aimed to investigate the mecC and mecA genes in MRSA strains isolated from different geographic regions in Turkey. Methods: The sample of the study consisted of 494 MRSA strains isolated from seven geographical regions in Turkey between 2013 and 2016. The strains were obtained from 17 centers, comprising 13 university hospitals, three education and research hospitals, and one state hospital. Methicillin resistance in S. aureus strains was determined using the agar disk diffusion method with a cefoxitin disk and the agar dilution method with oxacillin. The mecC and mecA genes in MRSA strains was investigated by Polymerase Chain Reaction (PCR). Results: Of the MRSA strains investigated, 47.9% were isolated from intensive care units. Concerning sample type, 36.7% were detected in the respiratory tract (tracheal aspirate, sputum, etc.), 24.8% in blood, 18.7% in skin and soft tissues, 9.3% in nasal swabs, 5.4% in urine, 4.1% in ears, and 1% in sterile body fluid. Using PCR, mecC was not identified in any of the S. aureus strains isolated from different clinical microbiology laboratories. mecA gene positivity was found in 315 of the MRSA strains (63.8%). Staphylococcal Cassette Chromosome mec ( SCCmec) type was identified in 232 strains (46.9%), of which 136 (58.7%) were type II, 75 (32.4%) were type IV, 12 (5.1%) were type Mb, six (2.5%) were type I, and three (1.3%) were type III. Conclusion: This is the first multi-centered study to investigate MRSA strains isolated from different regions in Turkey. The mecC gene was not detected in any of the MRSA strains. We believe that this study will constitute an important basis for monitoring possible future changes. (C) 2019 The Authors. Published by Elsevier Limited on behalf of King Saud Bin Abdulaziz University for Health Sciences.
Absorption Ratio of Treatment Couch and Effect on Surface and Build-Up Region Doses
(Elsevier Science Bv, 2018) Tugrul, Taylan
Aim: In this study, at different fields, energies and gantry angles, treatment couch and rails dose absorption ratio and treatment couch effect on surface and build-up region doses were examined. Background: It is assumed that radiation attenuation is minimal because the carbon fiber couches have low density and it is not generally accounted for during treatment planning. Consequently, it leads to a major dosimetric mistake. Materials and methods: Solid water phantom was used for relative dose measurement. The measurements were done using a Farmer ion chamber with 0.6 cc volume and a parallel plane ion chamber starting from surface with 1 mm depth intervals at 10 x 10 cm(2) field, SSD 100 cm. Measurements were taken for situations where the beams intersect the couch and couch rails. Results: Dose absorption ratio of carbon fiber couch obtained at gantry angle of 180 was 1.52%, 0.69%, 0.33% and 0.25% at different field sizes for 6 MV. For 15 MV, this ratio was 0.95%, 0.27%, 0.20% and 0.05%. The absorption ratio is between 3.4% and 1.22% when the beams intersect with couch rails. The couch effect increased surface dose from 14% to 70% for 6 MV and from 11.34% to 53.03% for 15 MV. Conclusions: The results showed that the carbon fiber couch increased surface dose during posterior irradiation. Therefore, the skin -sparing effect of the high energy beams was decreased. If the effect of couch is not considered, it may cause significant differences at dose which reaches the patient and may cause tissue problems such as erythema. (C) 2017 Greater Poland Cancer Centre. Published by Elsevier Sp. z o.o. All rights reserved.
Accelerated Atherosclerosis in Haemodialysis Patients; Correlation of Endothelial Function With Oxidative Dna Damage
(Oxford Univ Press, 2012) Kaya, Yuksel; Ari, Elif; Demir, Halit; Soylemez, Nihat; Cebi, Aysegul; Alp, Hakan; Beytur, Ali
Background. Accelerated atherosclerosis is the major cause of mortality in patients on chronic haemodialysis (HD). The aim of this study was to evaluate the relationship between oxidative DNA damage [8-hydroxy-2'-deoxyguanosine/deoxyguanosine ratio (8-OHdG/dG ratio)], oxidative stress biomarkers and endothelial function in HD patients as an indicator of atherosclerosis. Methods. Forty-four chronic HD patients without known atherosclerotic disease and 55 age- and sex-matched healthy individuals were included in the study. Plasma malondialdehyde (MDA) levels and 8-OHdG/dG ratio were determined as oxidative stress markers. Superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were measured as antioxidants. Endothelial function was assessed by ultrasonography. Results. 8-OHdG/dG ratio and MDA levels were higher in HD patients than controls while SOD and GPx activities were lower in HD patients compared to controls. Flow-mediated dilatation FMD% in HD patients were lower than the control group (7.28 +/- 0.79 versus 11.18 +/- 0.82, P < 0.001). There was a significant negative correlation between FMD% and 8-OHdG/dG ratio (r = -0.678, P < 0.01) and MDA levels (r = 0.517, P < 0.01), while there was a significant positive correlation between FMD% and SOD (r = 0.538, P < 0.01) and GPx levels (r = 0.720, P < 0.01). Conclusions. Our data have demonstrated that HD patients exhibit increased oxidative DNA damage and decreased antioxidant activity. We propose that endothelial function is negatively correlated with 8-OHdG/dG ratio and positively correlated with antioxidant enzymes. To our knowledge, this is the first study to demonstrate the inverse relationship between endothelial function and plasma oxidative DNA damage in HD patients.

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