61 results on '"Aygün H"'
Search Results
2. Interval-valued intuitionistic fuzzy subgroups based on interval-valued double t-norm
- Author
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Aygünoğlu, A., Varol, B. Pazar, Çetkin, V., and Aygün, H.
- Published
- 2012
- Full Text
- View/download PDF
3. Spherical fuzzy soft sets: Theory and aggregation operator with its applications.
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Güner, E. and Aygün, H.
- Subjects
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SOFT sets , *AGGREGATION operators , *OPERATOR theory , *PROBLEM solving , *FUZZY sets - Abstract
The aim of this paper is to redefine the notion of spherical fuzzy soft sets as a more general concept to make them more functional for solving multi-criteria decision-making problems. We first define the set operations under the new spherical fuzzy soft set environment and obtain some fundamental properties of them. Then, we construct the spherical fuzzy soft aggregation operator which allows establishing a more efficient and useful method to solve the multi-criteria decision-making problems. We establish an algorithm for the decision-making process which is more useful, simple, and easier than the existing methods. After constructing the method for solving the decision-making problem, we give a numerical example based on linguistic terms to show that the validity of the proposed technique. Finally, we analyze the reliability of the results of this method with the help of the comparative studies by applying this to a real-time data set and using the existing methods. [ABSTRACT FROM AUTHOR]
- Published
- 2022
4. The Phenomenon of Thrombotic Microangiopathy in Cancer Patients
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Alexander Vorobev, Victoria Bitsadze, Fidan Yagubova, Jamilya Khizroeva, Antonina Solopova, Maria Tretyakova, Nilufar Gashimova, Kristina Grigoreva, Sabina Einullaeva, Maria Drozhzhina, Aygun Hajiyeva, Emilia Khalilulina, Alexander Cherepanov, Daredzhan Kapanadze, Elena Egorova, Nart Kuneshko, Jean-Christophe Gris, Ismail Elalamy, Cihan Ay, and Alexander Makatsariya
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thrombotic microangiopathy ,cancer patients ,thrombotic thrombocytopenic purpura ,thrombo-inflammation ,ADAMTS13 ,drug-induced TMA ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Thrombotic microangiopathy (TMA) encompasses a range of disorders characterized by blood clotting in small blood vessels, leading to organ damage. It can manifest as various syndromes, including thrombotic thrombocytopenic purpura (TTP), hemolytic-uremic syndrome (HUS), and others, each with distinct causes and pathophysiology. Thrombo-inflammation plays a significant role in TMA pathogenesis: inflammatory mediators induce endothelial injury and activation of platelet and coagulation cascade, contributing to microvascular thrombosis. Primary TMA, such as TTP, is primarily caused by deficient ADAMTS13 metalloproteinase activity, either due to antibody-mediated inhibition or intrinsic enzyme synthesis defects. In cancer patients, a significant reduction in ADAMTS13 levels and a corresponding increase in VWF levels is observed. Chemotherapy further decreased ADAMTS13 levels and increased VWF levels, leading to an elevated VWF/ADAMTS13 ratio and increased thrombotic risk. Drug-induced TMA (DITMA) can result from immune-mediated or non-immune-mediated mechanisms. Severe cases of COVID-19 may lead to a convergence of syndromes, including disseminated intravascular coagulation (DIC), systemic inflammatory response syndrome (SIRS), and TMA. Treatment of TMA involves identifying the underlying cause, implementing therapies to inhibit complement activation, and providing supportive care to manage complications. Plasmapheresis may be beneficial in conditions like TTP. Prompt diagnosis and treatment are crucial to prevent serious complications and improve outcomes.
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- 2024
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5. In vitro activities of moxifloxacin and ciprofloxacin against Staphylococcus aureus isolates: P1198
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Azap, A., özkan, S., Aygün, H., Gül, S., Yagci, D., Memikoglu, O. K., and Tekeli, E.
- Published
- 2005
6. An algebraic perspective on neutrosophic sets: fields and linear spaces.
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Çetkin, V., Varol, B. Pazar, and Aygün, H.
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VECTOR spaces - Abstract
In this work, we intend to introduce and study another algebraic structure of single-valued neutrosophic sets called neutrosophic field as a continuation of our investigations on neutrosophic algebraic structures. For this goal, we define the concept of neutrosophic fields and observe some of their basic characteristics and properties. Then we give the definition of a neutrosophic linear space over the proposed neutrosophic field and consider its fundamental properties. [ABSTRACT FROM AUTHOR]
- Published
- 2021
7. Relative compactness in L-fuzzy topological spaces
- Author
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Aygün, H., Kudri, S.R.T., and Warner, M.W.
- Published
- 2000
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8. P-Closedness in L-fuzzy topological spaces
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Aygün, H. and Kudri, S.R.T.
- Published
- 2000
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9. On (L,M)-Double Fuzzy Filter Spaces
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Abd El-Latif, A. A., primary, Aygün, H., additional, and Çetkin, V., additional
- Published
- 2018
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10. Dampster'in Birleştirme Kuralı ile Sınıflandırma Algoritmalarının Birleştirilmesi
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AYGÜN, H. and ADALI, E.
- Abstract
Bu çalışmada sınıflandırma sonuçlarını iyileştirmek için yeni bir yöntem önerilmektedir. Önerilen Yöntem Dempster’in Birleştirme Algoritmasını kullanarak farklı sınıflandırmalarından elde edilen sonuçların birleştirilmesidir. Dempster’in Birleştirme Algoritmasının kullanımıyla yapılan birleştirme işleminin, birleşimde kullanılan her bir sınıflandırma algoritmasından daha başarılı sonuçlar verdiği ortaya konmuştur. Ayrıca Önerilen yöntemin mevcut birleşik algoritmalardan daha başarılı olduğu da gösterilmiştir. Sınıflandırmanın doğruluğunu arttırmak amacıyla birleştirme işleminde Güven derecesi kullanımı önerilmiştir. Güven derecesi kullanımının daha doğru sınıflandırma gerçeklediği gösterilmiştir.
- Published
- 2016
11. Analysis of Myomectomy during Cesarean Section: A Tertiary Center Experience
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Mehmet Sakinci, Gokce Turan, Cem Yasar Sanhal, Yunus Yildiz, Aygun Hamidova, Fatma Ceren Guner, Alime Buyuk, Nasuh Utku Dogan, and Safak Olgan
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cesarean section ,myomectomy ,myoma ,pregnancy ,cesarean myomectomy ,complications ,Surgery ,RD1-811 - Abstract
Purpose This study analyzed the safety of myomectomy during the cesarean section (CS). Methods Pregnant women who underwent myomectomy during CS in a tertiary center between January 2015 and November 2019 were included in the study in Group A, and pregnant women who did not have myoma and who underwent only CS were included in the study in Group B. The following information was obtained from patient files in hospital archives and was then recorded and compared: age, gravidity, parity, gestational week, characteristics of the myomas (i.e., location, size, number, and type), duration of surgery, perioperative complications, need for blood transfusion, preoperative and postoperative hemoglobin (Hb) values, duration of surgery, and hospital stay duration. Results A total of 83 patients underwent CS plus myomectomy (Group A), and 80 patients (without myoma) underwent only CS (Group B).There were no statistically significant differences between the groups in terms of preoperative and postoperative Hb values or blood transfusion rates (p > 0.05). Hospitalization and surgery duration were significantly higher in the group that underwent CS myomectomy (p = 0.001 and p = 0.001, respectively). The mean myoma size was 8.3 ± 4.1 cm in Group A. There was a statistically significant and inverse correlation between the size of the myoma and the delivery week (p = 0.035). There was a statistically significant and positive correlation between the myoma size and hospital stay (p = 0.01). Conclusion Myomectomy during CS is safe and can be applied regardless of the location, size, type, and number of myomas. However, to make myomectomy routine during CS, multi-center studies that include more cases are needed.
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- 2022
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12. EVALUTION OF THE RELATIONSHIP BETWEEN THE LEVEL OF PRESERVICE AND INSERVICE SCIENCE TEACHERS’ SCIENTIFIC LITERACY, SELF-EFFICACY AND ATTITUDES
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AKGÜN, Abuzer, ÖZDEN, Mustafa, ÇİNİCİ, Ayhan, SONEKĐNCĐ, Ayşe, and AYGÜN, H. Ali
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Fen Eğitimi,Fen ve Teknoloji Okuryazarlığı,Öz-yeterlik,Tutum ,Science Education,Scientific Literacy,Self-Efficacy,Attitude - Abstract
Bu araştırmanın amacı fen bilgisi öğretmenlerinin ve fen bilgisi öğretmen adaylarının fen-teknoloji okuryazarlık seviyeleri ile öz yeterlik ve tutum düzeyleri arasındaki ilişkiyi incelemektir. Çalışmanın örneklemini Adıyaman Üniversitesi Eğitim Fakültesi İlköğretim Bölümü Fen Bilgisi Öğretmenliği programında öğrenim gören 30 öğretmen adayı ve Adıyaman ilinde görev yapan 30 Fen ve Teknoloji Öğretmeni oluşturmaktadır. Betimsel tarama modelinde ilişkisel tarama yönteminin kullanıldığı bu araştırmada verilerin toplanmasında “Fen ve Teknoloji Okuryazarlık Ölçeği”, “Fen Öğretimi Öz Yeterlik Ölçeği” ve “Fen Öğretimi Tutum Ölçeği” kullanılmıştır. Araştırma sonuçlarına göre, öğretmenlerin fen ve teknoloji okuryazarlık düzeyleri öğretmen adaylarına göre daha yüksektir. Diğer taraftan öğretmen adaylarının Fen ve Teknoloji Okuryazarlık düzeylerinin öz yeterlik ve tutum üzerinde yol açtığı değişim kontrol edildiğinde ise öz yeterlik ve tutum düzeyleri arasında pozitif yönde bir ilişki olduğu belirlenmiştir., The purpose of this study is to investigate the relationship between preservice and in-service science teachers’ scientific literacy levels, their self-efficacies and attitudes towards science. The sample group consisted of thirty preservice teachers enrolled in Adıyaman University, Faculty of Education, Department of Science Education and thirty in service science teachers employed at various schools. As data collection tool, Scientific Literacy Test, Self-Efficacy about science and science attitude were all used. According to the results of the study, it is revealed that in-service science teachers’ scientific literacy level is higher compared to preservice science teachers. Besides, there is a positive relationship between those two groups’ self-efficacy and attitudes levels.
- Published
- 2014
13. Some Good Extensions of Compactness in Sostak's L-Fuzzy Topology
- Author
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AYGÜN, H. and ABBAS, S. E.
- Published
- 2014
14. (r,s)-Convergent Nets
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AYGÜN, H. and ABBAS, S.e.
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Statistics and Probability ,Intuitionistic fuzzy set,Intuitionistic fuzzy topology,2000 AMS Classification: 54 A 20 ,İstatistik ve Olasılık - Abstract
We introduce the notions of (r, s)-adherent point, (r, s)-accumulation point, (r, s)-cluster point, (r, s)-limit point and (r, s)-derived set in an intuitionistic fuzzy topological spaces and investigate some of their properties. Also, we define (r, s)-convergent nets and investigate some of their properties.
- Published
- 2014
15. Behaviour of ultrasonic waves in porous rigid materials: an anisotropic Biot-Attenborough model
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Aygün, H, primary and Barlow, C, additional
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- 2015
- Full Text
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16. Interval-valued intuitionistic fuzzy subgroups based on interval-valued double t-norm
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Aygünoğlu, A., primary, Varol, B. Pazar, additional, Çetkin, V., additional, and Aygün, H., additional
- Published
- 2011
- Full Text
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17. Implementation of switching unit of a cross-connet system
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Aygün, H. Berkay, İnan, Kemal, and Diğer
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Cross linking ,Elektrik ve Elektronik Mühendisliği ,Switching ,Electrical and Electronics Engineering - Abstract
öz SAYISAL ÇAPRAZ BA?LANTI SİSTEMİNİN ANAHTARLAMA ÜNİTESİNİN TASARLANMASI VE GERÇEKLEŞTİRİLMESİ AYGÜN, H. Berkay Yüksek Lisans Tezi, Elektrik ve Elektronik Mühendisliği Ana Bilim Dalı Tez Yöneticisi: Prof. Dr. Kemal İNAN Ocak, 1993, 76 sayfa. Bu tezde PTT Araştırma ve Geliştirme Müdürlüğü tarafından prototipi üretilen Sayısal Çapraz Bağlantı Sisteminin Veri ve Sinyalleşme Anahtarlama Ünitesinin mimarisi ve tasarımı ile bu ünitenin kontrolünü gerçekleştiren yazılımlar anlatılmaktadır. Ünite kişisel bilgisayarda bulunan bir yazılım ile sürekli iletişim halindedir. Bu yazılım kullanılarak anahtarlama yapmak veya kaldırmak mümkündür. Anahtar Kelimeler: Tasarım, Anahtarlama, Sayısal Çapraz Bağlantı Sistemleri, Bilgisayar Kontrollü Sistemler. Biim Dalı Sayısal Kodu: 609.02.07 iv ABSTRACT IMPLEMENTATION OF SWITCHING UNIT OF A CROSS CONNECT SYSTEM AYGÜN H. Berkay M.S. in Electrical and Electronics Engineering Supervisor: Prof. Dr. Kemal İNAN February, 1993, 76 pages. In this study, the hardware and software architecture of data and signalling switching unit of the Cross Connect System of PTT R&D has been implemented. The switch is interfaced to a software running on a personal computer. Through this interface operator can establish or clear connections. Keywords: Implementation, Switching, Cross Connect Systems, Computer controlled systems. Science Code: 609.02.07 m 76
- Published
- 1993
18. Insertion Loss of Clamped Perforated and Non-Perforated Poroelastic Plate Silencers with Flow
- Author
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Aygün, H., primary and Attenborough, K., additional
- Published
- 2008
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19. ON (L, M)-FUZZY CLOSURE SPACES.
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AYGÜN, H., Ç:ETKIN, V., and ABBAS, S. E.
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TOPOLOGICAL spaces , *CLOSURE spaces , *FUNCTION spaces , *FUZZY sets , *SET theory - Abstract
The aim of this paper is to introduce (L, M)-fuzzy closure structure where L and M are strictly two-sided, commutative quantales. Firstly, we define (L, M)-fuzzy closure spaces and get some relations between (L, M)double fuzzy topological spaces and (L, M)-fuzzy closure spaces. Then, we introduce initial (L, M)-fuzzy closure structures and we prove that the category (L, M)-FC of (L, M)-fuzzy closure spaces and (L, M)-C-maps is a topological category over the category SET. From this fact, we define products of (L, M)-fuzzy closure spaces. Finally, we show that an initial structure of (L, M)-double fuzzy topological spaces can be obtained by the initial structure of (L, M)-fuzzy closure spaces induced by them. [ABSTRACT FROM AUTHOR]
- Published
- 2012
20. The Development and the Growth Features of Sprouts of Malus Orientalis Uglitzk.Species Introduced in Absheron
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Ceyran Najafova, Aynur Arabzade, and Aygun Huseynova
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malus orientalis ,absheron ,taxon ,embryo ,Agriculture ,Plant culture ,SB1-1110 - Abstract
Apple is cultivated in most of the temperate regions due to the fruit’s quality, its easiness to propagate, and its natural aptitude to bear. Malus classifications differ primarily in the taxonomic level at which infrageneric groupings of species are recognized. Object of the study was oriental apple (Malus orientalis Uglitzk) from Azerbaijan flora which was introduced to Absheron. The conducted experiments showed that the first sprouts of the seeds of the Malus orientalis sown in autumn were observed in the third decade of March. The first embryo roots which gives start to the main roots begin growth in germinal period before the ontogenesis. Thus, experiments have shown that Malus orientalis specie have normal growth in the ontogenesis initial development - germinal stage and it can be used as a perspective species for greening of Absheron.
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- 2017
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21. Exergo-economic cost accounting for PW4000 turbofan engine and its components
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Aygun Hakan, Cilgin Mehmet E., and Turan Onder
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Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
You The several series of PW4000 high bypass turbofan engine have used so far in many aircrafts. These commercial engines have played a crucial role on passenger and freight transportations. Namely, these engines are closely related to the environment impacts and security of energy supply. In this article, exergoeconomic analysis which is useful tool to investigate existing potential for improvement of the a system efficiency were carried out. The assesment, design and optimization of energy consuming systems are performed by means of these analyses. Therefore, thermo-economic costs were assigned to existing exergetic values of PW400 engine. Also exergo-economic performance parameters were evaluated. Finally, exergoeconomic deputy parameters were examined to understand relations with exergo-economic parameters. Based on the results of exergo-economics analysis, for Fan and exhaust, specific thrust costs are estimated 5.7051 $/hkN and 68.45$/hkN respectively. Also exergo-economics factor of PW4000 is found 7.958 % , while relative cost difference is determined at highest rate with 24.458 % for combustion chamber . With examination relations between economic variables and exergo-economic performance parameters, the change between 0.6 and 1.2 $/kg in the fuel price leads to increase the exhaust and fan specific thrust costs with 82.4701 $/hkN and 5.4332 $/hkN respectively. It is expected that conclusions of this study are helpful to notify exergo-economic impact of PW4000 engine Also, it may be benchmarking for similar gas turbine engines.
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- 2020
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22. On Intuitionistic Fuzzy 2-Metric Spaces
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Güner Elif, Çetkin Vildan, and Aygün Halis
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Information technology ,T58.5-58.64 - Abstract
In this study, we first recall the notion of an intuitionistic fuzzy 2-metric space and fundamental definitions with several illustrative examples. Then we define the notion of δ−chainable space and (δ,λ)−uniform locally contractive mapping between intuitionistic fuzzy 2-metric spaces. After that, by using the proposed concepts, we obtain a few fixed point theorems of self-mappings defined on this spaces.
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- 2018
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23. Evaluation of clinical, radiological and pathological findings in the identification of a spinal cord lesion in a paraplegic dog
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KILIC E, YAYLA S, ERMUTLU CS, KAYA M, AYGUN H, and SOZMEN M
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Veterinary medicine ,SF600-1100 - Published
- 2013
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24. Tendon healing and repair: a review of current approaches
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AYGUN H, CAKAR A, and ATILLA HA
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Veterinary medicine ,SF600-1100 - Published
- 2013
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25. Perioperative and postoperative effects of hydrostatic pressure applied to the dura mater on central nervous system in unilateral biportal endoscopic spine surgery.
- Author
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Çevikkalp E, Aygün H, Yıldız K, and Efe EM
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- Humans, Male, Female, Middle Aged, Adult, Aged, Endoscopy methods, Spine surgery, Dura Mater surgery, Hydrostatic Pressure, Optic Nerve, Postoperative Complications etiology, Postoperative Complications prevention & control
- Abstract
Objectives: To evaluate the changes in optic nerve sheath diameter (ONSD) caused by this pressure applied to the dura mater and postoperative complications., Methods: The study was conducted between 01.01.2022 and 01.06.2022 at Private Medicabil Hospital. The ONSD was measured 3 mm behind the eyeball using US at 5 time points: T1 (in the supine position after anesthesia induction), T2 (after conversion to the prone position), T3 (in the prone position after applying pressure to the dura mater), T4 (in the prone position after the discontinuation of applying pressure to the dura mater), T5 (after conversion to the supine position). Postoperative complications were recorded., Results: The ONSD at T3 was higher than those at all time points. For an ONSD value >5.3 mm, the sensitivity, specificity, positive predictive, and negative predictive values were 87.5%, 71.9%, 50.9%, and 94.5%, respectively (Area under the curve 0.830, 95% Confidence Interval: 0.761-0.899, p <0.001) CONCLUSION: We think that the hydrostatic pressure applied to the dura mater in unilateral biportal endoscopic (UBE) surgeries causes changes in the ONSD sheath diameter and that monitoring ONSD with peroperative USG can reduce the possible complications in order to reduce the effects of this pressure on the central nervous system., (Copyright: © Neurosciences.)
- Published
- 2024
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26. Comparison of forearm and intra-arterial blood pressure measurements according to body and arm positions in obese patients.
- Author
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Günay Ismailoğlu E, Aygün H, Şahan S, Ergin E, and Geçtan E
- Abstract
Rationale: Noninvasive blood pressure (BP) monitoring is very important also difficult for accurate diagnosis and monitor of obese patients., Aims: The study aimed to assess the agreement between forearm arm BP and intra-arterial BP values in a different body and arm positions in obese patients., Methods: The descriptive study was carried out on 60 intensive care patients with a body mass index above 30 kg/m
2 who were monitored with invasive radial BP in the general and surgical intensive care units. BP values obtained from the upper arm and forearm with different arm and body positions were compared with intra-arterial BP results. Bland-Altman analysis and correlation coefficient were used for the accuracy of upper and forearm noninvasive BP reading in different positions., Results: The best agreement was found between the forearm systolic BP in the supine and half-sitting position with the arm down and intra-arterial BP values. Also, the best agreement in diastolic BP was found between the half-sitting and half-sitting position with the arm down and intra-arterial BP., Conclusions: Forearm systolic BP measurement, especially in the supine and half-sitting position with the arm below the heart level position, was best agreement with intra-arterial measurement, regarded as the gold standard. For this reason, it is more appropriate to use forearm BP measurement in obese patients monitored in intensive care to obtain accurate results., (© 2024 John Wiley & Sons Ltd.)- Published
- 2024
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27. An innovative method to prevent infection when measuring the arterial blood gas SpO2 saturation.
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Şahan S, Güler S, Geçtan E, and Aygün H
- Abstract
Background: Patients are hospitalized for extended periods, particularly in intensive care units (ICUs). As a result, the saturation probe (pulse oximeter) remains attached for an extended period and microorganisms can grow in the wet environment. If the pulse oximeters are not reprocessed, cross-infection may occur. The literature contains several studies in which gloves were used for the measurement while various SpO
2 (peripheral arterial oxygen saturation) measurements were compared with each other. However, such comparisons have yet to be made with the results of arterial blood gas SpO2 measurements by pulse oximeter, considered as the gold standard. The present study aimed to compare arterial blood gas values with the fingertip saturation measurement performed by having adult patients wear gloves of different colors, one after the other, on their fingers and determining the effect of the differently colored gloves (transparent, white, black, light blue) on saturation values., Methods: The study was conducted on 54 patients in an ICU. Intra-arterial blood gas SpO2 results were measured. Oxygen saturation was measured while the patient 1. did not wear gloves and 2. sequentially wore a series of gloves of different colors. Paired t-test, correlation analysis, and Bland Altman charts were used to evaluate the results., Results: The mean SpO2 % value of the participants' intra-arterial blood gas measurements was 97.76±2.04. The mean SpO2 % value obtained from the measurements of the fingers with a transparent glove was 0.43 points lower than the mean SpO2 % value of the intra-arterial blood gas measurements (t=0.986, p=0.61). The mean SpO2 % value obtained from the measurements of the fingers with a white glove was 0.93 points lower than the mean SpO2 % value of the intra-arterial blood gas measurements (t=1.157, p=0.093)., Conclusion: Of the measurements performed with a glove, the mean SpO2 % value obtained from the measurements of the fingers with a transparent glove was more consistent with the mean SpO2 % value of the intra-arterial blood gas measurements than measurement of the fingers without a glove., Competing Interests: The authors declare that they have no competing interests., (Copyright © 2024 Şahan et al.)- Published
- 2024
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28. Evaluation of Patients with COVID-19 Followed Up in Intensive Care Units in the Second Year of the Pandemic: A Multicenter Point Prevalence Study.
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Güngör S, Ediboğlu Ö, Yazıcıoğlu Moçin Ö, Adıgüzel N, Tuncay E, Ekiz İşcanlı İG, Er B, Karakurt Z, Turan S, Kosovalı BD, Mutlu NM, Kayar D, Gökbulut Bektaş Ş, Uysal E, Seğmen F, Alp G, Erdem D, Has Selmi N, Güven P, Özçelik Z, Ocakcıoğlu M, Yazıcı Özgür C, Yılmaz R, Bilgi Özel D, Cebeci H, Güler B, Cansever C, Çakırca M, İnceöz H, Solmaz İ, Özkan Sipahioğlu F, Aydın EM, Dayanır H, Öner SF, Karatepe U, Özen S, Boran M, Ergül DF, Kasapoğlu US, Delen LA, Toy E, Altun K, Albayrak T, Yanal H, Zaim G, Yarar V, Kılınç G, Deniz M, Özdemir E, Soylu VG, Yılmaz A, Saygılı SM, Öztürk EK, Ergan B, Eyüpoğlu S, Şahin Y, Yüksel B, Bulut A, Sarıtaş A, Yeniay H, Genç M, Kargın F, Özcan O, Karakoç E, Karaca Ü, Sözütek D, Sarı S, Şenoğlu N, Aygün H, Yiğit AC, Kavruk N, Uzan ÇA, Bıçakcıoğlu M, Solak S, Kutbay Özçelik H, Uluç K, Yıldırım İ, Arar MC, Demirel İ, Küver SU, Özgür ES, Aydın K, Erdal Dönmez G, Aygencel G, Esmaoğlu A, Sebil Aydın B, Tokur ME, Korkmaz Ekren P, Aydemir Y, Çakır Güney B, Erdil ÖY, Tünay A, Bahadır T, Uçkun S, Kocaoğlu N, Pınar HU, Kutluer Karaca N, Gültekin H, Ayvat P, Belin Özer A, Eroğlu A, Kuyrukluyıldız U, Baytar Ç, Ayoğlu H, Mızrakçı S, Metin H, Zanbak Mutlu ÖP, Yılmaz H, and Tüzüner F
- Abstract
Objective: A 1-day point prevalence study was planned to obtain country data by determining the clinical characteristics, follow-up and treatment methods of coronavirus disease 2019 (COVID-19) cases that required intensive care unit (ICU) treatment in the second year of the pandemic., Material and Methods: All patients who were hospitalized in the ICUs due to COVID-19 between March 11, 2022, 08.00 am, and March 12, 2022, 08.00 am, were included in the study. Demographic characteristics, intensive care and laboratory data, radiological characteristics, and follow-up results of the patients were recorded., Results: A total of 811 patients from 59 centers were included in the study, 59% of the cases were male, and the mean age was 74 ± 14 years. At least one comorbid disease was present in 94% of the cases, and hypertension was the most common. When ICU weight scores were examined, Acute Physiology and Chronic Health Evaluation-II: 19 (15-27) and Sequential Organ Failure Assessment: 7 (4-10) were seen. Sepsis was present in 37% (n = 298) of cases. PaO2/FiO2 ratios of the patients were 190 the highest and 150 the lowest and 51% of the cases were followed via invasive mechanical ventilation. On the study day, 73% bilateral involvement was seen on chest x-ray, and ground-glass opacities (52%) were the most common on chest tomography. There was growth in culture in 40% (n = 318) of the cases, and the most common growth was in the tracheal aspirate (42%)., Conclusion: The clinical course of COVID-19 is variable, and ICU follow-up was required due to advanced age, comorbidity, presence of respiratory symptoms, and widespread radiological involvement. The need for respiratory support and the presence of secondary infection are important issues to be considered in the follow-up. Despite the end of the second year of the pandemic and vaccination, the high severity of the disease as well as the need for follow-up in ICUs has shown that COVID-19 is an important health problem.
- Published
- 2023
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29. Resistive Warming Mattress, Forced-Air Warming System, or a Combination of the Two in the Prevention of Intraoperative Inadvertent Hypothermia: A Randomized Trial.
- Author
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Okgün Alcan A, Aygün H, and Kurt C
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- Humans, Prospective Studies, Intraoperative Complications prevention & control, Body Temperature, Hypothermia prevention & control, Hypothermia etiology
- Abstract
Purpose: To prevent intraoperative inadvertent hypothermia (IIH), resistive products and forced-air warming systems are often used simultaneously. There is insufficient evidence to show whether this application is clinically more effective than a single active warming device. The aim of this study is to compare the efficacy a single intraoperative active warming method with combined methods in IIH prevention., Design: A randomized, prospective, experimental study., Methods: This study was conducted between June and October 2021 in the operating room of a training and research hospital. The study sample consisted of 123 patients who underwent scheduled orthopedic surgery under spinal anesthesia, were young (18-64), and had an ASA risk score of I to III. The patients were divided into three groups preoperatively according to the stratified randomization technique. To prevent IIH, a resistive warming mattress was used in group 1; a forced-air warming system was used in group 2; and a combination of the two methods were used in group 3. The body temperatures of the patients were measured and recorded every 15 minutes from admission to the operating room until the end of surgery., Findings: The mean intraoperative body temperature of the patients was 36.6±0.15˚C for group 1; 36.6±0.1˚C for Group 2 and 36.6 ± 0.15˚C for Group 3. There was no difference between the groups in terms of body temperature. The overall incidence of IIH was 8.1%; 9.8% in group 1, 9.8% in group 2 and 4.9% in group 3. There was no statistically significant difference between the groups in terms of IIH (p < .05)., Conclusions: This study supports the efficacy of using resistive warming mattress and forced-air warming systems in preventing IIH. The use of both methods together made no difference in terms of IIH development., (Copyright © 2022 American Society of PeriAnesthesia Nurses. Published by Elsevier Inc. All rights reserved.)
- Published
- 2023
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30. Innovation in measuring obese patients' blood pressure: measurement with conical wrapping technique.
- Author
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Şahan S, Şahin S, Aygün H, and Yildiz A
- Subjects
- Adolescent, Adult, Arm, Blood Pressure, Humans, Male, Middle Aged, Radial Artery, Blood Pressure Determination, Obesity
- Abstract
Introduction: Accurate measurement of blood pressure (BP) is difficult in obese patients due to their upper arm shape and width. Errors made during BP measurement cause misdiagnosis or lead to wrong treatment., Method: The data of this methodological study were collected from 40 patients who were 18 years old or above, with a BMI above 25 kg/m2, and who were followed up with radial catheter arterial pressure in adult intensive care and postoperative care units between March and December 2020., Results: In total 55% of the participants were male with a mean age of 63.9 years, mean height of 165.7 cm, mean weight of 85.2 kg and mean BMI of 31.0 ± 2.1 kg/m2. Intra-arterial BP (IABP) measurement values were found to be correlated with conical wrapping technique and cylindrical wrapping technique (P < 0.001). As a result, a statistically significance was found between conical SBP and intra-arterial SBP (r = 0.921; P < 0.05) and conical DBP and intra-arterial DBP (r = 0.902; P < 0.05)., Conclusion: It was determined that the SBP and DBP results of the conical wrapping technique were closer to the results obtained by IABP measurements. For this reason, it is more appropriate to measure BP with conical wrapping technique in clinically obese patients., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)
- Published
- 2022
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31. The effect of Madopar on absence‑like seizures in WAG/Rij rats.
- Author
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Al-Kaleel A, Erbaş O, and Aygün H
- Subjects
- Animals, Benserazide, Disease Models, Animal, Drug Combinations, Electroencephalography, Levodopa therapeutic use, Male, Rats, Rats, Wistar, Seizures chemically induced, Seizures drug therapy, Epilepsy, Absence drug therapy
- Abstract
The aim of this study was to investigate the effect of Madopar on the absence seizures and the anxiety‑like behavior (assessed using the open field test) in Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats. Twenty‑eight male WAG/Rij rats were randomly divided into four groups: group I: control; group II: Madopar 5 mg/kg; group III: Madopar 50 mg/kg; group IV: Madopar 100 mg/kg. A tripolar electrode was attached to all WAG/Rij rats. Electrocorticography (ECoG) recordings were made before and after Madopar (5, 50, and 100 mg/kg) injection for three hours. Anxiety‑related behavior was studied using the open field test for 5 min after the ECoG recordings. Madopar significantly reduced the number and duration of spike‑wave discharges (SWDs) when compared to the control group. The highest dose of Madopar (100 mg/kg) significantly reduced the duration of SWDs when compared to Madopar (5 mg/kg). All Madopar doses did not alter the duration of grooming, but the highest doses of Madopar significantly increased the number of squares crossed in the open field test when compared to the control and Madopar (5 mg/kg) groups. These results revealed that Madopar reduced the absence‑like seizures and the anxiety‑related behavior in WAG/Rij rats. This may emphasize the therapeutic properties of the Madopar/L‑dopa in absence epilepsy.
- Published
- 2022
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32. Vitamin D may prevent COVID-19 induced pregnancy complication.
- Author
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Al-Kaleel A, Al-Gailani L, Demir M, and Aygün H
- Abstract
SARS-CoV-2 enters target cells via the ACE2 receptor and downregulates it. ACE2 exhibits high catalytic activity to produce Angiotensin 1-7 (Ang-1-7), which has a vasodilator effect and also inactivates the vasoconstrictor Angiotensin II. In normal pregnancy ACE2 expression is raising in the uterus and placenta. Ang-1-7 levels in plasma are significantly higher in third-trimester pregnant women when compared to non-pregnant women. This may be contributing to systemic vasodilation and reduced blood pressure and modulating hemodynamics during pregnancy. Interestingly, Ang-1-7 plasma levels are lower in pregnancies complicated by pre-eclampsia than normal pregnancies. COVID-19 infection increased the inflammatory cytokines and reduced ACE2 level. This may lead to pre-eclampsia or hypertensive pregnancies, then increasing the perinatal and maternal mortality and morbidity. Vitamin D increased ACE2 expression and Ang-1-7 plasma levels and also decreased Ang II level in plasma. Moreover, Vitamin D reduced the inflammatory cytokine storm. So, Vitamin D supplementation can prevent the risk of preeclampsia or hypertension in pregnant women with COVID-19., (Copyright © 2021 Elsevier Ltd. All rights reserved.)
- Published
- 2021
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33. The Role of NMDA Receptors in the Effect of Purinergic P2X7 Receptor on Spontaneous Seizure Activity in WAG/Rij Rats With Genetic Absence Epilepsy.
- Author
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Doǧan E, Aygün H, Arslan G, Rzayev E, Avcı B, Ayyıldız M, and Ağar E
- Abstract
P2X7 receptors (P2X7Rs) are ATP sensitive cation channels and have been shown to be effective in various epilepsy models. Absence epilepsy is a type of idiopathic, generalized, non-convulsive epilepsy. Limited data exist on the role of P2X7Rs and no data has been reported regarding the interaction between P2X7Rs and glutamate receptor NMDA in absence epilepsy. Thus, this study was designed to investigate the role of P2X7 and NMDA receptors and their possible interaction in WAG/Rij rats with absence epilepsy. Permanent cannula and electrodes were placed on the skulls of the animals. After the healing period of the electrode and cannula implantation, ECoG recordings were obtained during 180 min before and after drug injections. P2X7R agonist BzATP, at doses of 50 μg and 100 μg (intracerebroventricular; i.c.v.) and antagonist A-438079, at doses of 20 μg and 40 μg (i.c.v.) were administered alone or prior to memantine (5 mg/kg, intraperitoneal; i.p.) injection. The total number (in every 20 min), the mean duration, and the amplitude of spike-wave discharges (SWDs) were calculated and compared. Rats were decapitated and the right and left hemisphere, cerebellum, and brainstem were separated for the measurements of the advanced oxidation protein product (AOPP), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), catalase (CAT), glutathione peroxide (GPx), and glutathione reductase (GR). BzATP and A-438079 did not alter measured SWDs parameters, whereas memantine reduced them, which is considered anticonvulsant. BzATP did not alter the anticonvulsant effect of memantine, while A-438079 decreased the effect of memantine. Administration of BzATP increased the levels of SOD and GR in cerebrum hemispheres. A-438079 did not alter any of the biochemical parameters. Memantine reduced the levels of MDA, GSH, and GR while increased the level of CAT in the cerebrum. Administration of BzATP before memantine abolished the effect of memantine on MDA levels. The evidence from this study suggests that P2X7Rs does not directly play a role in the formation of absence seizures. P2X7Rs agonist, reduced the antioxidant activity of memantine whereas agonist of P2X7Rs reduced the anticonvulsant action of memantine, suggesting a partial interaction between P2X7 and NMDA receptors in absence epilepsy model., (Copyright © 2020 Doǧan, Aygün, Arslan, Rzayev, Avcı, Ayyıldız and Ağar.)
- Published
- 2020
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34. Hyperbaric oxygen therapy decreases QTc dispersion that increased in CO poisoning.
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Bağli BS and Aygün H
- Subjects
- Adult, Aged, Aged, 80 and over, Arrhythmias, Cardiac blood, Arrhythmias, Cardiac etiology, Arrhythmias, Cardiac physiopathology, Carbon Monoxide Poisoning blood, Carbon Monoxide Poisoning complications, Carbon Monoxide Poisoning physiopathology, Electrocardiography, Female, Humans, Male, Middle Aged, Troponin blood, Young Adult, Arrhythmias, Cardiac therapy, Carbon Monoxide Poisoning therapy, Hyperbaric Oxygenation methods
- Abstract
Myocardial injury is a frequent consequence of moderate to severe CO (carbon monoxide) poisoning and a significant predictor of mortality in CO injury. Electrocardiography (ECG) is an easily accessible diagnostic tool for evaluating myocardial damage. Increased QT interval and QT dispersion are related to heterogeneity of regional ventricular repolarization and can develop into arrhythmias. It has been reported that QT interval and QT dispersion increase in patients with CO poisoning. Hyperbaric oxygen (HBO2) therapy has been used successfully in treating patients with CO poisoning. The aim of this study was to investigate change of corrected QT (QTc) interval and QTc dispersion after HBO2 therapy. This study included 31 patients with CO poisoning. QTc dispersion increased in patients with CO poisoning. The mean QTc dispersion was 54.94 milliseconds (ms) on admission. The mean QTc dispersion decreased to 35.74 ms after HBO2 therapy (P=0.003). There was also a correlation between carboxyhemoglobin level and QTc dispersion (P=0.029). HBO2 therapy, which decreases QTc dispersion, may improve the myocardial electrical homogeneity and reduce the risk of ventricular arrhythmia and cardiac death. Physicians should be aware of the effect of HBO2 therapy on myocardial damage when treating patients with CO poisoning. The ECGs should be examined carefully before referring or excluding HBO2 therapy., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)
- Published
- 2018
35. Effect of platelet-rich fibrin on epidural fibrosis and comparison to ADCON® Gel and hyaluronic acid.
- Author
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Demirel E, Yildiz K, Çadirci K, Aygün H, Şenocak E, and Gündoğdu B
- Subjects
- Adjuvants, Immunologic pharmacology, Animals, Disease Models, Animal, Drug Therapy, Combination methods, Fibrosis, Organic Chemicals pharmacology, Rats, Rats, Sprague-Dawley, Treatment Outcome, Epidural Space drug effects, Epidural Space pathology, Hyaluronic Acid pharmacology, Laminectomy adverse effects, Laminectomy methods, Lumbar Vertebrae surgery, Platelet-Rich Fibrin, Postoperative Complications pathology, Postoperative Complications prevention & control
- Abstract
Objective: In this experimental study, PRF (Platelet Rich Fibrin), HA (Hyaluronic Acid) gel and ADCON® Gel were compared in terms of preventing epidural fibrosis., Methods: Twenty-eight Sprague-Dawley rats (mean weight, 400-450 g) were divided into 4 groups. L3-L4 laminectomy was performed in each group. Following laminectomy, Adcon® Gel, HA gel and PRF were applied onto the surgery site locally in Group 1, 2 and 3, respectively. Group 4 was maintained as control without any local application. After five weeks, L3-L4 vertebrae were removed totally and taken to histopathological evaluation for epidural fibrosis, acute inflammatory cell density, chronic inflammatory cell density, hemorrhage, angiogenesis and new bone formation., Results: Acute inflammation cell density, angiogenesis, and new bone formation levels were comparable among the study groups (p > 0.05). However, new bone formation was higher in the PRF group. Epidural fibrosis and chronic inflammatory cell density were significantly lower in the PRF group (p < 0.05)., Conclusion: We concluded that PRF contributed to hemostasis and prevented epidural fibrosis., (Copyright © 2018 Turkish Association of Orthopaedics and Traumatology. All rights reserved.)
- Published
- 2018
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36. [Amoebic liver abscess in a patient initially diagnosed with pneumonia: case report and discussion of relevant literature].
- Author
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Kurt Ö, Aktaş N, Çalışkan C, Karatuna O, Aygün H, and Akyar I
- Subjects
- Anti-Infective Agents therapeutic use, DNA, Protozoan analysis, Diagnosis, Differential, Drainage, Dysentery, Amebic complications, Entamoeba histolytica genetics, Entamoeba histolytica isolation & purification, Feces parasitology, Humans, Liver Abscess, Amebic parasitology, Liver Abscess, Amebic therapy, Male, Polymerase Chain Reaction, Tomography, X-Ray Computed, Turkey, Young Adult, Liver Abscess, Amebic diagnosis, Pneumonia diagnosis
- Abstract
In one-third of the patients with amoebiasis, amoebic liver abscess (ALA) may occur after the penetration of amoebic trophozoites through the intestinal wall. ALA is seen mostly among men aged 20-45 years with a serious clinical outcome, with fever and abdominal pain on the right upper quadrant. Most patients have no recent history of amoebic colitis; indeed, they have neither gastrointestinal complaints nor Entamoeba histolytica (E. histolytica) cysts/trophozoites in their stools. Therefore, ultrasonography and serology are primary in ALA diagnosis, while searching for E. histolytica DNA in abscess fluid using PCR has been preferred as an effective and reliable method, lately. Early antimicrobial therapy is effective; however, for cases irresponsive to therapy after 72 hours and with large abscess, drainage or surgical intervention is indicated. If left untreated, ALA may disseminate to other organs and cause death. The data concerning the extra-intestinal manifestations of amebiasis in Turkey are limited. Here, a rare case of a young man with an initial diagnosis of pneumonia followed by the identification of ALA after radiological interventions and laboratory tests is presented and the relevant literature is discussed.
- Published
- 2015
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37. Clinical and radiological comparison of posterolateral fusion and posterior interbody fusion techniques for multilevel lumbar spinal stabilization in manual workers.
- Author
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Aygün H, Cakar A, Hüseyinoğlu N, Hüseyinoğlu U, and Celik R
- Abstract
Study Design: Eighty-four patients who had been treated for degenerative spinal diseases between January 2006 and June 2009 were reviewed retrospectively., Purpose: We aimed to compare the clinical and radiologic findings of manual workers who underwent posterolateral fusion (PLF) or posterior interbody fusion (PLIF) involving fusion of 3 or more levels of the spine., Overview of Literature: Previous studies have concluded that there is no significant difference between the clinical outcome of PLF and PLIF techniques., Methods: After standard decompression, 42 patients underwent PLF and the other 42 patients underwent PLIF. Radiologic findings, Oswestry disability index (ODI) scores, and visual analogue scale (VAS) scores were assessed preoperatively and at 6-month intervals postoperatively and return to work times/rates were assessed for 48 months., Results: Patients who underwent PLF had significantly shorter surgical time and less blood loss. According to the 48-month clinical results, ODI and VAS scores were reduced significantly in the two groups, but the PLIF group showed better results than the PLF group at the last follow-up. Return to work rate was 63% in the PLF group and 87% in the PLIF group. Union rates were found to be 81% and 89%, respectively, after 24 months (p=0.154)., Conclusions: PLIF is a preferable technique with respect to stability and correction, but the result does not depend on only the fusion rates. Discectomy and fusion mass localization should be considered for achieving clinical success with the fusion technique. Before performing PLIF, the association of the long operative time and high blood loss with mortality and morbidity should be taken into consideration, particularly in the elderly and disabled patients.
- Published
- 2014
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38. Protective effect of melatonin on adriamycin-induced cardiotoxicity in rats.
- Author
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Bilginoğlu A, Aydın D, Ozsoy S, and Aygün H
- Subjects
- Animals, Cardiotoxicity etiology, Electrocardiography, Male, Rats, Rats, Wistar, Antioxidants pharmacology, Cardiotoxicity prevention & control, Doxorubicin toxicity, Heart drug effects, Lipid Peroxidation drug effects, Melatonin pharmacology
- Abstract
Objectives: Adriamycin is one of the most widely used anticancer drugs. The major limiting factor of using this drug is the development of cardiotoxicity. However, melatonin (N-acetyl-5-methoxytryptamine) is a ubiquitous molecule as a good antioxidant that may protect the heart. We investigated whether or not pretreatment with melatonin can attenuate adriamycin-induced cardiotoxicity., Study Design: All procedures and experiments were approved by the Animal Ethics Committee of Gazi Osman Paşa University (2012-HADYEK-022). Adult male Wistar-Albino rats were randomly divided into four groups, namely control (CON, n=7), melatonin (MEL, n=7), adriamycin (ADR, n=7), and adriamycin+melatonin (ADR+MEL, n=7) groups. Cardiotoxicity in rats was induced by adriamycin injection (cumulative dose: 18 mg/kg, intraperitoneal [i.p.]) at an interval of 24 hours (h) on the 5th, 6th and 7th days. Rats receiving melatonin treatment in the adriamycin group received melatonin (10 mg/kg/day, i.p.) for 7 days and were injected with adriamycin (18 mg/kg, i.p.) on 5th, 6th and 7th days. On the 8th day, gravimetric, electrocardiography (ECG) and biochemical parameters were assessed., Results: Adriamycin induction caused changes in the ECG pattern, including ST-segment elevation and decreased R-amplitude, increase in the serum levels of cardiac injury markers (creatine kinase [CK], CK-MB, aspartate transaminase, and lactate dehydrogenase), decrease in the antioxidant enzymes activity (superoxide dismutase, glutathione peroxidase), elevated lipid peroxidation (malondialdehyde), and altered lipid profile in the serum. Melatonin treatment prevented all the parameters of adriamycin-induced cardiotoxicity in rats., Conclusion: Melatonin has a protective effect on the heart against adriamycin-induced cardiotoxicity in rats.
- Published
- 2014
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39. Does platelet-rich plasma enhance microfracture treatment for chronic focal chondral defects? An in-vivo study performed in a rat model.
- Author
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Hapa O, Çakici H, Yüksel HY, Fırat T, Kükner A, and Aygün H
- Subjects
- Animals, Biomarkers metabolism, Cartilage, Articular metabolism, Chondrocytes metabolism, Chronic Disease, Collagen Type II biosynthesis, Disease Models, Animal, Injections, Intralesional, Lower Extremity surgery, Male, Rats, Rats, Sprague-Dawley, Wound Healing, Bone Regeneration drug effects, Cartilage, Articular drug effects, Platelet-Rich Plasma
- Abstract
Objective: The purpose of the present study was to compare the effectiveness of platelet-rich plasma (PRP) + microfracture and microfracture treatments in the healing of chronic focal chondral defects., Methods: The study included 57 adult male Sprague-Dawley rats. Forty-two rats were divided into three groups of 14 rats with a chondral defect (control, microfracture only, PRP+microfracture). The remaining 15 rats were used to produce the PRP preparation. The rats were then euthanatized at 3 and 6 weeks after treatment and examined. Histological analysis using the modified Pineda scoring system and immunohistochemical staining for Type 2 collagen were performed., Results: At both time intervals, control group histological scores (Week 3: 8.8±1.2, Week 6: 8.5±0.7) were higher than microfracture (Week 3: 6.8±1.0, Week 6: 7.1±0.6) and PRP+microfracture (Week 3: 6.4±1.3, Week 6: 5.7±1.2) scores (p<0.05). The microfracture group score was higher at Week 6 than the PRP+microfracture group (p<0.05). The degree of Type 2 collagen staining was higher at Week 6 in the PRP+microfracture group and was unique in showing staining at the cell membrane., Conclusion: The addition of PRP application to microfracture treatment appears to enhance cartilage healing in chronic focal chondral defects.
- Published
- 2013
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40. Effect of platelet-rich plasma on tendon-to-bone healing after rotator cuff repair in rats: an in vivo experimental study.
- Author
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Hapa O, Cakıcı H, Kükner A, Aygün H, Sarkalan N, and Baysal G
- Subjects
- Animals, Disease Models, Animal, Follow-Up Studies, Injections, Intraoperative Period, Male, Rats, Rats, Sprague-Dawley, Plastic Surgery Procedures, Rotator Cuff pathology, Rotator Cuff surgery, Tendon Injuries pathology, Platelet-Rich Plasma, Rotator Cuff Injuries, Tendon Injuries therapy, Wound Healing
- Abstract
Objective: The purpose of this experimental study was to analyze the effects of local autologous platelet-rich plasma (PRP) injection on tendon-to-bone healing in a rotator cuff repair model in rats., Methods: Rotator cuff injury was created in 68 left shoulders of rats. PRP was obtained from the blood of an additional 15 rats. The 68 rats were divided into 4 groups with 17 rats in each group; PRP group (Week 2), control group (Week 2), PRP group (Week 4), and control group (Week 4). Platelet-rich plasma or saline was injected to the repair area intraoperatively. Rats were sacrificed 2 and 4 weeks after the surgery. Histological analysis using a semiquantitative scoring was performed on 7 rats per group. Tendon integrity and increases in vascularity and inflammatory cells and the degree of new bone formation were evaluated and compared between the groups. The remaining tendons (n=10) were mechanically tested., Results: Degree of inflammation and vascularity were less in the study group at both time intervals (p<0.05). Tendon continuity was better in the study group at 2 weeks (p<0.05). Obvious new bone formation was detected in the control group at 4 weeks (p<0.05). Biomechanically, platelet-rich plasma-treated specimens were stronger at 2 weeks (p<0.05)., Conclusion: Local autologous PRP injection may have beneficial effects on initial rotator cuff tendon-to-bone healing and enhance initial tendon-to-bone healing remodeling. This may represent a clinically important improvement in rotator cuff repair.
- Published
- 2012
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41. Ultrasonic wave propagation in stereo-lithographical bone replicas.
- Author
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Aygün H, Attenborough K, Lauriks W, and Langton CM
- Subjects
- Algorithms, Computer Simulation, Femur Head diagnostic imaging, Humans, Ilium diagnostic imaging, Lumbar Vertebrae diagnostic imaging, Ultrasonography, Water, Bone and Bones diagnostic imaging, Models, Biological
- Abstract
Predictions of a modified anisotropic Biot-Allard theory are compared with measurements of pulses centered on 100 kHz and 1 MHz transmitted through water-saturated stereo-lithographical bone replicas. The replicas are 13 times larger than the original bone samples. Despite the expected effects of scattering, which is neglected in the theory, at 100 kHz the predicted and measured transmitted waveforms are similar. However, the magnitude of the leading negative edge of the waveform is overpredicted, and the trailing parts of the waveforms are not predicted well. At 1 MHz, although there are differences in amplitudes, the theory predicts that the transmitted waveform is almost a scaled version of that incident in conformity with the data.
- Published
- 2010
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42. Predictions of angle dependent tortuosity and elasticity effects on sound propagation in cancellous bone.
- Author
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Aygün H, Attenborough K, Postema M, Lauriks W, and Langton CM
- Subjects
- Acoustics, Air, Algorithms, Animals, Anisotropy, Cattle, Humans, Models, Biological, Porosity, Bone and Bones physiology, Elasticity, Sound
- Abstract
The anisotropic pore structure and elasticity of cancellous bone cause wave speeds and attenuation in cancellous bone to vary with angle. Previously published predictions of the variation in wave speed with angle are reviewed. Predictions that allow tortuosity to be angle dependent but assume isotropic elasticity compare well with available data on wave speeds at large angles but less well for small angles near the normal to the trabeculae. Claims for predictions that only include angle-dependence in elasticity are found to be misleading. Audio-frequency data obtained at audio-frequencies in air-filled bone replicas are used to derive an empirical expression for the angle-and porosity-dependence of tortuosity. Predictions that allow for either angle dependent tortuosity or angle dependent elasticity or both are compared with existing data for all angles and porosities.
- Published
- 2009
- Full Text
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43. Oligonucleotides suppress PKB/Akt and act as superinductors of apoptosis in human keratinocytes.
- Author
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Kippenberger S, Müller J, Schultz M, Dorn A, Bock A, Aygün H, Thaçi D, Hofmann M, Kaufmann R, and Bernd A
- Subjects
- Animals, Cells, Cultured, DNA pharmacology, ErbB Receptors metabolism, Humans, Keratinocytes cytology, Keratinocytes enzymology, Mutation, Myeloid Differentiation Factor 88 genetics, Myeloid Differentiation Factor 88 metabolism, Oligodeoxyribonucleotides chemistry, Proto-Oncogene Proteins c-akt metabolism, Toll-Like Receptor 9 genetics, Toll-Like Receptor 9 metabolism, Apoptosis, Keratinocytes drug effects, Oligodeoxyribonucleotides pharmacology, Proto-Oncogene Proteins c-akt antagonists & inhibitors
- Abstract
DNA oligonucleotides (ODN) applied to an organism are known to modulate the innate and adaptive immune system. Previous studies showed that a CpG-containing ODN (CpG-1-PTO) and interestingly, also a non-CpG-containing ODN (nCpG-5-PTO) suppress inflammatory markers in skin. In the present study it was investigated whether these molecules also influence cell apoptosis. Here we show that CpG-1-PTO, nCpG-5-PTO, and also natural DNA suppress the phosphorylation of PKB/Akt in a cell-type-specific manner. Interestingly, only epithelial cells of the skin (normal human keratinocytes, HaCaT and A-431) show a suppression of PKB/Akt. This suppressive effect depends from ODN lengths, sequence and backbone. Moreover, it was found that TGF alpha-induced levels of PKB/Akt and EGFR were suppressed by the ODN tested. We hypothesize that this suppression might facilitate programmed cell death. By testing this hypothesis we found an increase of apoptosis markers (caspase 3/7, 8, 9, cytosolic cytochrome c, histone associated DNA fragments, apoptotic bodies) when cells were treated with ODN in combination with low doses of staurosporin, a well-known pro-apoptotic stimulus. In summary the present data demonstrate DNA as a modulator of apoptosis which specifically targets skin epithelial cells.
- Published
- 2009
- Full Text
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44. Sequencing of single and double stranded RNA oligonucleotides by acid hydrolysis and MALDI mass spectrometry.
- Author
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Bahr U, Aygün H, and Karas M
- Subjects
- Base Sequence, Hydrogen-Ion Concentration, Hydrolysis, Oligoribonucleotides analysis, RNA analysis, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Acids chemistry, Oligoribonucleotides chemistry, Oligoribonucleotides genetics, RNA chemistry, RNA genetics, Sequence Analysis, RNA methods
- Abstract
Treatment of RNA oligonucleotides with strong acids at pH 1-2 rapidly leads to hydrolysis of the phosphodiester bonds at the 5'-position of ribose. Analysis of the resulting degradation products by MALDI coupled to an Orbitrap high resolution mass spectrometer shows almost complete mass ladders from both sides of the nucleotides without interfering fragments from base losses or internal fragments. From the mass differences between adjacent peaks of a mass ladder, the sequence can be determined. Low cleavage efficiency at the termini leads to 2mers and 3mers which can be identified by MS/MS. In this way the complete sequences of different siRNA 21mer single and double strands could be verified. This simple and fast method can be applied for controlling sequences of synthetic oligomers, as well as for de-novo sequencing. Moreover, the method is applicable for localization and identification of RNA modifications as demonstrated using the examples of an oligonucleotide with phosphorothioate backbone and of one containing 2'-methoxy-ribose modifications.
- Published
- 2009
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45. Detection and relative quantification of siRNA double strands by MALDI mass spectrometry.
- Author
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Bahr U, Aygün H, and Karas M
- Subjects
- RNA, Double-Stranded chemistry, RNA, Small Interfering analysis, RNA, Small Interfering chemistry, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization methods
- Abstract
While MALDI-MS is widely accepted for quality control of synthetic oligonucleotides, this method has been regarded as not applicable for a control of the purity and correct annealing of double strands. The results presented here show that the double-strand intensities measured by MALDI-MS maintain and reflect the solution conditions. Using a single-stranded RNA as internal standard, the double-strand intensity can be determined by measuring the intensity ratio of the single strands to the standard under "native" conditions and after denaturation with formic acid. For siRNAs with fully matched 20-21 base pairs, relative intensities of the double strands are between 94 and 97.2%. The stability determined by MALDI-MS for different RNA duplexes correlates well with calculated T m values and the content of G-C pairs. Furthermore, the quantification method enables one to determine an excess of one single strand and the contribution of duplex formation by truncated strands. The results show that MALDI-MS is a fast and reliable method for quality control of synthetic siRNA.
- Published
- 2008
- Full Text
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46. Vertical mattress suture technique: an alternative vascular anastomosis.
- Author
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Aygün H and Yildirim OS
- Subjects
- Anastomosis, Surgical, Animals, Blood Flow Velocity, Femoral Artery pathology, Male, Rats, Rats, Sprague-Dawley, Femoral Artery surgery, Suture Techniques, Vascular Surgical Procedures methods
- Abstract
The objective of this study was to introduce the vertical mattress (VM) suture technique and compare its patency and postoperative healing with other commonly used suture techniques. Thirty-two Sprague-Dawley rats were randomly assigned to one of four suture techniques to be applied to both femoral arteries: continuous (C), interrupted (I), VM, and VM with flap (VMF) sutures. The operating time and the degree of postanastomotic leakage were recorded. The milking test was employed 5 and 15 minutes and 14 days after the operation to attain patency. Blood flow velocity was determined using ultrasonography at 1 hour and on days 1 and 14 postoperation. Rats then were sacrificed, and anastomotic lining tissues were harvested for histopathologic examination. Anastomoses by C and I were executed in 12.06 and 18.31 minutes. Modified suture techniques took longer to execute anastomosis (23.09 minutes for VM and 32.44 minutes for VMF). VM suture technique was superior to other suture techniques in terms of anastomotic leakage, quality of filling, and blood flow velocity. Also, absence of the luminal closure or constriction, intimal injury and hyperplasia, foreign body inflammation, and inversion were noted in histopathology. In conclusion, the VM suture technique could be considered for microvascular surgery.
- Published
- 2008
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47. [Case report: two Leuconostoc bacteremia cases].
- Author
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Aygün H, Bozkurt GY, Memikoğlu O, and Cokça F
- Subjects
- Adult, Anti-Bacterial Agents therapeutic use, Bacteremia drug therapy, Catheters, Indwelling microbiology, Clindamycin therapeutic use, Gram-Positive Bacterial Infections drug therapy, Humans, Leuconostoc drug effects, Male, Postoperative Complications drug therapy, Postoperative Complications microbiology, Vancomycin Resistance, Anti-Bacterial Agents pharmacology, Bacteremia microbiology, Clindamycin pharmacology, Gram-Positive Bacterial Infections microbiology, Leuconostoc isolation & purification
- Abstract
Leuconostoc species, which are the members of Streptococcaceae family, have recently been recognized as potential pathogens. They usually cause infections in patients with underlying disease, with venous catheters or previously treated with vancomycin. In this report, we have presented two cases of Leuconostoc bacteremia. The first case was a 42 years old male patient who was diagnosed to have colon adenocarcinoma. He had undergone colon, stomach and distal pancreas resection operation and had given chemotherapy. Blood and catheter cultures yielded methicillin-resistant Staphylococcus aureus. Blood cultures were repeated since teicoplanin therapy had failed, and Gram positive cocci resistant to vancomycin were isolated. The other case was a 26 years old male patient who had undergone a shunt operation because of pineal lesion and hydrocephaly. He had given ampirical vancomycin therapy since he had post-operative high fever, however the therapy had failed. The catheter culture yielded Gram positive cocci resistant to vancomycin. Both isolates were identified as Leuconostoc spp. with API 20 strep identification kit (Bio Merieux), and both of them were found sensitive to penicillin, ampicillin, clindamycin, gentamicin and chloramphenicol, while they were resistant to teicoplanin and vancomycin. The patients were successfully treated with clindamycin. It is concluded that, Leuconostoc spp. should be considered when vancomycin-resistant organisms resembling streptococci are isolated from blood cultures.
- Published
- 2005
48. Effect of proline to alanine mutation on the thermal stability of the all-beta-sheet protein tendamistat.
- Author
-
Zscherp C, Aygün H, Engels JW, and Mäntele W
- Subjects
- Enzyme Inhibitors metabolism, Models, Molecular, Mutation, Peptides metabolism, Protein Denaturation, Protein Structure, Secondary, Spectroscopy, Fourier Transform Infrared, Temperature, Alanine metabolism, Enzyme Inhibitors chemistry, Peptides chemistry, Peptides genetics, Proline metabolism, Protein Structure, Tertiary
- Abstract
The temperature dependent denaturation of wild-type tendamistat and of the proline-free triple mutant P7A/P9A/P50A was investigated using Fourier-transform infrared (FTIR) spectroscopy. Whereas the temperature-induced unfolding is reversible in the wild type, aggregation was observed for the proline-free tendamistat when studied under the same conditions. The midpoint unfolding temperature T(m) was found as 82.3+/-0.5 degrees C in (2)H2O. The thermal stability of the proline-free mutant is reduced by 15 degrees C as compared to the wild type. Changes in the strength of hydrogen bonding of tyrosine O-H groups upon unfolding and aggregation are reflected in small shifts of the C-C stretching mode of the aromatic ring near 1515 cm(-1). Evaluation of data from different infrared (IR) bands sensitive to changes in secondary structure as well as to changes in tertiary structure strongly supports a two-state model for the unfolding process of wild-type tendamistat.
- Published
- 2003
- Full Text
- View/download PDF
49. Structural variations and stabilising modifications of synthetic siRNAs in mammalian cells.
- Author
-
Czauderna F, Fechtner M, Dames S, Aygün H, Klippel A, Pronk GJ, Giese K, and Kaufmann J
- Subjects
- Endoribonucleases metabolism, HeLa Cells, Humans, Methylation, Oligonucleotides, Antisense genetics, PTEN Phosphohydrolase, Phosphatidylinositol 3-Kinases biosynthesis, Phosphatidylinositol 3-Kinases genetics, Phosphoric Monoester Hydrolases biosynthesis, Phosphoric Monoester Hydrolases genetics, Protein Serine-Threonine Kinases biosynthesis, Protein Serine-Threonine Kinases genetics, Proto-Oncogene Proteins c-akt, RNA Stability, RNA, Double-Stranded chemistry, RNA, Double-Stranded genetics, Transfection, Tumor Suppressor Proteins biosynthesis, Tumor Suppressor Proteins genetics, Proto-Oncogene Proteins, RNA Interference, RNA, Small Interfering chemistry, RNA, Small Interfering genetics
- Abstract
Double-stranded short interfering RNAs (siRNA) induce post-transcriptional silencing in a variety of biological systems. In the present study we have investigated the structural requirements of chemically synthesised siRNAs to mediate efficient gene silencing in mammalian cells. In contrast to studies with Drosophila extracts, we found that synthetic, double-stranded siRNAs without specific nucleotide overhangs are highly efficient in gene silencing. Blocking of the 5'-hydroxyl terminus of the antisense strand leads to a dramatic loss of RNA interference activity, whereas blocking of the 3' terminus or blocking of the termini of the sense strand had no negative effect. We further demonstrate that synthetic siRNA molecules with internal 2'-O-methyl modification, but not molecules with terminal modifications, are protected against serum-derived nucleases. Finally, we analysed different sets of siRNA molecules with various 2'-O-methyl modifications for stability and activity. We demonstrate that 2'-O-methyl modifications at specific positions in the molecule improve stability of siRNAs in serum and are tolerated without significant loss of RNA interference activity. These second generation siRNAs will be better suited for potential therapeutic application of synthetic siRNAs in vivo.
- Published
- 2003
- Full Text
- View/download PDF
50. Kinetic mechanism and catalysis of a native-state prolyl isomerization reaction.
- Author
-
Pappenberger G, Bachmann A, Müller R, Aygün H, Engels JW, and Kiefhaber T
- Subjects
- Catalysis, Cyclophilins metabolism, Fluorescence, Humans, Hydrogen-Ion Concentration, Isomerism, Kinetics, Models, Molecular, Mutation genetics, Peptides genetics, Peptidylprolyl Isomerase metabolism, Proline genetics, Protein Conformation, Protein Denaturation, Protein Renaturation, Peptides chemistry, Peptides metabolism, Proline chemistry, Protein Folding
- Abstract
Folding of tendamistat is a rapid two-state process for the majority of the unfolded molecules. In fluorescence-monitored refolding kinetics about 8% of the unfolded molecules fold slowly (lambda=0.083s(-1)), limited by peptidyl-prolyl cis-trans isomerization. This is significantly less than expected from the presence of three trans prolyl-peptide bonds in the native state. In interrupted refolding experiments we detected an additional very slow folding reaction (lambda=0.008s(-1) at pH 2) with an amplitude of about 12%. This reaction is caused by the interconversion of a highly structured intermediate to native tendamistat. The intermediate has essentially native spectroscopic properties and about 2% of it remain populated in equilibrium after folding is complete. Catalysis by human cyclophilin 18 identifies this very slow reaction as a prolyl isomerization reaction. This shows that prolyl-isomerases are able to efficiently catalyze native state isomerization reactions, which allows them to influence biologically important regulatory conformational transitions. Folding kinetics of the proline variants P7A, P9A, P50A and P7A/P9A show that the very slow reaction is due to isomerization of the Glu6-Pro7 and Ala8-Pro9 peptide bonds, which are located in a region that makes strong backbone and side-chain interactions to both beta-sheets. In the P50A variant the very slow isomerization reaction is still present but native state heterogeneity is not observed any more, indicating a long-range destabilizing effect on the alternative native state relative to N. These results enable us to include all prolyl and non-prolyl peptide bond isomerization reactions in the folding mechanism of tendamistat and to characterize the kinetic mechanism and the energetics of a native-state prolyl isomerization reaction.
- Published
- 2003
- Full Text
- View/download PDF
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