Özaçmak, Veysel Haktan | Sayan, Hale | Aktunç, Erol

Other | 2009 | Türk Biyokimya Dergisi34 ( 2 ) , pp.82 - 88

Amaç: Adenozin ve adenozin A1 reseptör agonistleri, çeşitli dokuların reperfüzyon harabiyetine karşı önkoşullanma yoluyla koruyucu etkiler göstermektedir. Çalışmanın amacı, sıçan ince bağırsağının reperfüzyon harabiyeti üzerine adenozin A1/A2 reseptör aktivasyonunun etkilerini incelemekti. Yöntemler: Denekler herbiri rastgele sekiz hayvan içeren dört gruba ayrıldı: sham kontrol, iskemi-reperfüzyon kontrol, 5’-N-etilkarboksiamidoadenozin (NECA) (non-selektif A1 /A2 agonisti, 0.1 mg/kg, i.v.) tedavili iskemi-reperfüzyon ve teofilin (non-selektif A1 /A2 antagonisti, 20 mg/kg, i.v.) tedavili iskemi-reperfüzyon. Tedaviler iskemi yapılmad . . .an 5 dk önce uygulandı. Süperiyor mezenter arter 30 dk klempe edildikten sonra reperfüzyon dönemi 180 dk sürdü. Terminal ileum segmentlerinin, KCl, karbakol ve substans P’ye olan kasılma yanıtlarının kaydedilmesinin yanısıra, dokuların miyeloperoksidaz, malondialdehit ve indirgenmiş glutatyon miktarları da ölçüldü. Bulgular: İskemi, nötrofil infiltrasyonu ve lipid peroksidasyonunu ileri düzeyde yükseltirken aynı zamanda indirgenmiş glutatyonu düşürdü. Sham control grubuy- la karşılaştırıldığında, kasılma yanıtları iskemi-reperfüzyon grubunda ciddi düzeyde azaldı. NECA ön tedavisi, doku indirgenmiş glutatyon miktarını ileri derecede düzeltti ve ayrıca iskemi-reperfüzyon sonucu azalmış kasılma yanıtını kısmen iyileştirdi. Teofilin ile ön tedavi ise herhangi koruyucu bir etki göstermedi. Sonuç: Adenozin A1 /A2 reseptör aktivasyonunun, iskemi sonucu gelişen bağırsak kasılma bozukluğuna karşı kısmi koruma sağladığını ve ayrıca bu korumanın, indirgenmiş glutatyon düzeyinin fizyolojik seviyede tutulması yolu ile muhtemelen gerçekleştiğine dair ek kanıt önermekteyiz. Objectives: Adenosine and adenosine A1 receptor agonists exert protective effects against reperfusion injury in different tissues by mediating preconditioning. The aim of the present study was to examine the effects of adenosine A1 /A2 receptor activation on reperfusion-induced small intestinal injury in rat. Methods: Animals were randomized into four groups each including eight as following: sham control, ischemia-reperfusion control, 5’-N-ethylcarboxamidoadenosine (NECA) (non-selective A1 /A2 agonist, 0.1 mg/kg, i.v.)-treated I/R, and theophylline (non-selective A1 /A2 antagonist, 20 mg/kg, i.v.)-treated I/R groups. The treatments were administered 5 min before inducing ischemia in which superior mesenteric artery was clamped for 30 min followed by 180 min of reperfusion pe- riod. Myeloperoxidase, malondialdehyde, and reduced glutathione contents of terminal ileum samples were measured besides recording contractile responses to KCl, carbachol and substance P. Results: Ischemic insult significantly increased neutrophil infiltration and lipid peroxidation while decreasing the reduced glutathione. Contractile responses were seriously reduced in I/R group compared to that of the sham control group. NECA pretreatment alleviated the tissue content of reduced glutathione remarkably besides providing partial amelioration of I/R-reduced contractile response, while theophylline pretreatment had no any protective effect. Conclusion: We offer additional evidence that activation of A1 /A2 adenosine receptors provides partial protection against ischemia-induced intestinal contractile dysfunction possibly through maintaining reduced glutathione content at physiological levels Daha fazlası Daha az

Aydemir, Selim | Tekin, Solak Nilgün | Aktunç, Erol | Numanoğlu, Gamze | Üstündağ, Yücel

Article | 2004 | Turkish Journal of Gastroenterology15 ( 3 ) , pp.192 - 195

Amaç: Celiac hastalığı ince barsakların glutene intoleransı sonucu oluşan bir hastalıktır. Epidemiolojik çalışmalarda prevalansı hakkında çok farklı veriler vardı. Hastalarda genellikle çok geniş spektrumda semptom ve bulgulara neden olabildiğinden celiac hastalığı tanısının konulması zor olabilmektedir. Hastalığın erken evrede yakalanması önemlidir. Çünkü bu hastalarda barsak lenfoması gelişme riski artmıştır. Celiac hastalığı olan hastalarda rekürren aftoz stomatit prevalansındaki yükseklik nedeniyle rekürren aftoz stomatitli hastaların celiac hastalığı yönünden araştırılması asemptomatik celiac hastalığı olan hastaların tanı alma . . .sını sağlayabilir. Bu çalışma rekürren aftoz stomatit nedeniyle başvuran olgularda celiac hastalığı prevalansını saptamak için planlanmıştır. Yöntem: Çalışma gurubu olarak rekürren aftoz stomatit öyküsü olan, kontrol grubu olarak ise rekürren aftoz stomatit öyküsü olmayan olgular alındı. Tüm olgularda anti gliadin IgG, antigliadin IgA ve anti endomisium antikorları bakıldı. Ayrıca endoskopi yapılarak duodenum distal kesiminden biyopsiler alındı. Bulgular: Rekürren aftoz stomatit öyküsü olan 41 olgunun ikisinde patolojik inceleme ile doğrulanan celiac hastalığı bulundu (%4.8). Celiac hastalığı saptanan bu iki olgunun her ikisinde de anti gliadin IgA ve endomisium antikorları pozitif bulundu. Anti gliadin IgG antikoru ise olguların birinde pozitifti. Kontrol grubundaki 49 olgunun hiçbirinde celiac hastalığı saptanmadı. Sonuç: Rekürren aftoz stomatit olgularında celiac hastalığı açısında ileri incelenmeler yapılmalıdır. Endoskopinin invaziv ve daha pahalı olması nedeniyle rekürren aftoz stomatitli olgularda celiac hastalığı ı araştırmak için öncelikli olarak serolojik tetkikler yapılmalı, seroljik markır pozitif olan olgularda endoskopik olarak duodenum ikinci kesiminden biyopsiler alınmalıdır. Background/aims: Celiac disease is a condition related to the small intestine’s intolerance to gluten. In epidemiologic studies the prevalence is highly variable. The diagnosis can be difficult due to the wide spectrum of signs and symptoms. As the risk for intestinal lymphoma is higher in these patients, early diagnosis has its privileges. The higher prevalence of recurrent aphthous stomatitis in celiac disease led us to investigate the celiac disease prevalence in patients with recurrent aphthous stomatitis, which might assist in diagnosis of asymptomatic celiac disease patients. The aim of this study was to determine the prevalence of celiac disease in patients presenting with recurrent aphthous stomatitis. Methods: The study group consisted of patients having a history of recurrent aphthous stomatitis. The control group included patients not having aphthous stomatitis. Antibodies to gliadin IgG and IgA and antibodies to endomysium were determined from the serum samples of all patients. Biopsies were obtained from the distal part of the duodenum. Results: Biopsies of two patients (4.8%) out of 41 belonging to the study group were diagnosed as celiac disease. In serum samples of both, antibodies to gliadin IgA and antibodies to endomysium were found to be positive. Antibodies to gliadin IgG antibody were positive in only one of these two patients. None of the 49 patients in the control group was diagnosed as celiac disease. Conclusion: Further evaluation of recurrent aphthous stomatitis patients for celiac disease must be performed. As the endoscopic procedures are invasive and costly, evaluation of recurrent aphthous stomatitis patients for celiac disease must include serologic markers at the beginning. If any positivity is determined in markers, then endoscopic procedures including biopsies of the duodenum must be considered as the second-step intervention Daha fazlası Daha az

Özer, Mahmut | Bal, Abdullah

Article | 2004 | Istanbul University Journal of Electrical and Electronics Engineering4 ( 1 ) , pp.1091 - 1104

In this paper, we investigate dynamics of voltage-gated ionic channels which are of great importance in integrating the information received by neurons. Understanding of dynamical behavior of voltage-gated ionic channels plays a major role for determining underlying mechanism of spike activity and predicting the neuronal behavior. Investigation is carried out based on Hodgkin-Huxley (H-H) mathematical formalism. Ionic channel gate model is discussed briefly. Relaxation phenomenon is studied in the gate variables. Then effects of temperature on dynamics of gate variables are examined. Finally voltage-clamped simulations are carried o . . .ut to determine their dynamic behaviors based on squid giant axon. In this paper, we investigate dynamics of voltage-gated ionic channels which are of great importance in integrating the information received by neurons. Understanding of dynamical behavior of voltage-gated ionic channels plays a major role for determining underlying mechanism of spike activity and predicting the neuronal behavior. Investigation is carried out based on Hodgkin-Huxley (H-H) mathematical formalism. Ionic channel gate model is discussed briefly. Relaxation phenomenon is studied in the gate variables. Then effects of temperature on dynamics of gate variables are examined. Finally voltage-clamped simulations are carried out to determine their dynamic behaviors based on squid giant axon Daha fazlası Daha az

Kılıçay, Ebru | Hazer, Baki | Çoban, Burak | Scholz, Carmen

Article | 2010 | Hacettepe Journal of Biology and Chemistry38 ( 1 ) , pp.9 - 17

Pseudomonas oleovorans was grown with either 10-undecenoic acid alone or the equimolar mixture of octanoic acid and 10-undecenoic acid to obtain unsaturated poly(3- hydroxy alkanoates) (PHA)s; poly(3-hydroxy-10-undecenoate) (PHU) and poly(3-hydroxyoctanoate- co-3-hydroxy-10-undecenoate) (PHOU), respectively. The addition of bromine to olefinic double bond, by reacting the unsaturated PHA with bromine in homogeneous solution in dark, was readily carried out. The brominated PHA was reacted with polyethylene glycol (PEG) in the presence of a base to obtain PHA-g-PEG graft copolymers. The polymers were characterized by $^ 1H$ NMR and FT . . .IR spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Pseudomonas oleovorans was grown with either 10-undecenoic acid alone or the equimolar mixture of octanoic acid and 10-undecenoic acid to obtain unsaturated poly(3- hydroxy alkanoates) (PHA)s; poly(3-hydroxy-10-undecenoate) (PHU) and poly(3-hydroxyoctanoate- co-3-hydroxy-10-undecenoate) (PHOU), respectively. The addition of bromine to olefinic double bond, by reacting the unsaturated PHA with bromine in homogeneous solution in dark, was readily carried out. The brominated PHA was reacted with polyethylene glycol (PEG) in the presence of a base to obtain PHA-g-PEG graft copolymers. The polymers were characterized by $^ 1H$ NMR and FTIR spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) Daha fazlası Daha az

Aydemir, Selim | Bayraktaroğlu, Taner | Üstündağ, Yücel | Borazan, Ali | Sekirmez, Nedret | Aktunç, Erol | Numanoğlu, Gamze

Article | 2004 | Akademik Gastroenteroloji Dergisi3 ( 3 ) , pp.129 - 133

Giriş ve amaç: Standart üçlü tedavi ile Helicobacter pylori (H. pylori) eradikasyonu sağlanmayan olgularda ikinci tedavi ile eradikasyon daha zordur. H. pylori eradikasyon başarısızlıklarında uygulanacak tedavi kombinasyonları kesin belirlenmemiştir. Bu çalışmada lansoprazol, amoksisilin ve klaritromisin (LAK) ile yapılan standart üçlü tedavi ile H. pylori eradikasyonu sağlanamayan olgularda lansoprazol, ranitidin bizmut sitrat, tetrasiklin ve metronidazolden (LBTM) oluşan dörtlü tedavinin etkinliğini araştırdık. Gereç ve yöntem: Peptik ülser hastalığı veya nonülser dispepsi nedeniyle standart üçlü LAK tedavisi verilen ve H. pylori . . .eradikasyonu sağlanamayan toplam 36 olgu çalışmaya alındı. Bu olgulara lansoprazol (2x30 mg), ranitidin bizmut sitrat (2x400 mg), tetrasiklin (4x500 mg) ve metronidazolden (3x500 mg) oluşan dörtlü tedavi 14 gün verildi. Tedavinin bitiminden iki ay sonra endoskopik biyopsi ile H. pylori eradikasyonu değerlendirildi. Bulgular: Olgulardan beşi tedavi bitiminde kontrole gelmediğinden çalışma dışı bırakıldı. Dörtlü tedavi ile H. pylori eradikasyon oranı çalışmaya alınan tüm olgular değerlendirildiğinde %58.3, çalışma sonunda kontrole gelen olgular değerlendirildiğinde ise %67.7 saptandı. Sonuç: Bölgemizde standart LAK tedavisi ile H. pylori eradikasyonu sağlanamayan olgularda LBMT dörtlü tedavi kombinasyonunun başarı oranını oldukça düşük bulduk. Bu durumun ülkemizdeki metronidazol direncinin yüksek seviyelerde olması ile açıklanabileceğini düşünmekteyiz. Ülkemizde farklı bölgelerde H. pylorinin antibiyotik direnç durumunu ve tedavi başarısızlığı sebeplerini değerlendiren araştırmalara ihtiyaç vardır. Background/aim: Successful eradication of Helicobacter pylori (H. pylori) infection after failure of standard triple therapy is difficult. There are no guidelines on second-line therapies for H. pylori eradication failures. In the present study we investigated the efficacy of a 14-day quadruple regimen combining lansoprazole, ranitidine bismuth citrate (RBC), tetracycline and metronidazole as rescue treatment for Helicobacter pylori infection after failure of standard triple therapy combining lansoprazole, amoxicillin, clarithromycin (LAC). Materials and methods: A prospective study was designed consisting 36 patients infected with H. pylori and diagnosed with peptic ulcer or non-ulcer dyspepsia in whom triple therapy with LAC had failed. The patients were treated with quadruple therapy including lansoprazole, 30 mg twice daily, RBC, 400 mg twice daily, tetracycline, 500 mg four times daily, and metronidazole, 500 mg three times daily, for 14 days. Two months after completion of therapy, endoscopic biopsy evaluation was performed to confirm eradication. Results: Five cases who did not attend to the appointment were excluded from the study. With quadruple therapy, the H. pylori eradication rates were 58.3% by intention-to-treat analysis and 67.7% by per protocol analysis. Conclusion: The success rate of quadruple therapy with LBTM was found to be low in patients in whom standard triple therapy had failed in western Blacksea region. This finding may be explained by higher rates of metronidasole resistance in our country. We conclude that further studies about the drug resistance rates and explanation of reasons for treatment failure must be carried out Daha fazlası Daha az

Özer, Mahmut

Proceedings | 2003 | Mathematical and Computational Applications8 ( 1-3 ) , pp.71 - 78

In this study, phase-plane analysis is carried out for a simplified model of Purkinje cell dendrite in terms of voltage-gated ionic channels involved. State variables, nullclines and equilibrium points of the model are determined, and effects of ionic channel conductance and injected current on the shape of nullclines and the equilibrium points are investigated. In this study, phase-plane analysis is carried out for a simplified model of Purkinje cell dendrite in terms of voltage-gated ionic channels involved. State variables, nullclines and equilibrium points of the model are determined, and effects of ionic channel conductance and . . . injected current on the shape of nullclines and the equilibrium points are investigated Daha fazlası Daha az

Hazer, Baki | Hirao, Akira | Volga, Cüneyt

Article | 1999 | Macromolecular Chemistry and Physics200 ( 1 ) , pp.71 - 76

In order to synthesize benzoyl peroxide functionalized polystyrene (PSt), polyisoprene (PI) and poly(methyl methacrylate) (PMMA), anionic living PSt, PI, and PMMA were allowed to react with an excess amount of 4-(bromomethyl)benzoyl tert-butyl peroxide (BMtB) or bis[3,5-bis(bromomethyl)benzoyl] peroxide (BDBP) in tetrahydrofuran (THF) at -78°C. The results indicate that coupling reactions leading to dimers are significant during the reaction. Dimer formation was avoided when the living polystyrene was modified to the alcoholate anion by reaction with ethylene oxide (EO). © Wiley-VCH Verlag GmbH, 1999.

Menteş, Ayger | Sarbay, Mithat | Hazer, Baki | Arslan, Hülya

Article | 2005 | Applied Organometallic Chemistry19 ( 1 ) , pp.76 - 80

Mo(CO)6 was reacted with the Schiff base ligand obtained by condensation reaction of 2-acetyl- or benzoylpyridine with poly(propylene glycol)bis(2-aminopropyl ether) to obtain polymeric, dinuclear metal tetracarbonyl compounds. The long-chain Schiff base complexes are highly soluble even in non-polar solvents such as petroleum ether, diethyl ether and n-hexane. These complexes, as free-radical initiators, afforded methyl methacrylate polymerization in chlorinated solvents. Copyright © 2004 John Wiley & Sons, Ltd.

Tığlı-Aydın, Rahime Seda | Kazancı, Füsun

Article | 2018 | JAOCS, Journal of the American Oil Chemists' Society95 ( 11 ) , pp.1385 - 1398

In recent years, the use of ozonated oil (ozone enriched oil form) is being increasingly preferred for biomedical applications because of its antibacterial activity. Among most important reasons of this choice is the high molecular affinity of the ozone molecule and intracellular effects of the products of ozone and the unsaturated fatty-acid chemical reactions in cellular signaling systems. The aim of the present study was to synthesize and optimize the ozonated oil nanoemulsion system that would be transferred into the living systems easily, suggesting a promising carrier system for various biomedical applications. By varying form . . .ulation parameters (surfactant-to-oil ratio, surfactant concentration, mixing rate, and surfactant type), nanoemulsions were investigated in terms of mean particle diameters, distributions, and stabilities. Nanoemulsions with high stability and small droplet diameters (212.7 nm) could be produced under optimized conditions with Tween 40 as the surfactant at a 750 rpm mixing rate using the emulsion inversion point (EIP) low-energy method. Spherical and uniformly distributed nanoemulsions were observed by SEM, which also supports mean particle diameter measurements. Fourier-transform infrared spectroscopy (FTIR) and 13C NMR (nuclear magnetic resonance) studies indicated an ozonide structure within the nanoemulsion system, which remained even after 30 days of storage. The antibacterial activity of ozonated oil emulsions against Staphylococcus aureus and Escherichia coli suggests promising applications in the biomedical field. © 2018 AOC Daha fazlası Daha az

Korkut, Şeyda | Kılıç, Muhammet Samet | Hazer, Baki

Article | 2019 | Asia-Pacific Journal of Chemical Engineering14 ( 6 ) , pp.1385 - 1398

A copolymer poly(methyl methacrylate-co-vinylferrocene) was synthesized and used for the first time in a biofuel cell design. Bioanaode enzyme glucose oxidase and biocathode enzyme bilirubin oxidase were physically immobilized onto the copolymer-modified electrodes. Characterization studies were conducted by scanning electron microscopy, carbon-13, fourier transform infrared and hydrogen-1 nuclear magnetic resonance, and cyclic voltammograms. The designed biofuel cell was operated with linear sweep voltammetry. The maximum current was at 45°C with 120 µg of polymer amount. An improved power density of 323 µW cm-2 that is higher than . . . other ferrocene-based fuel cells was obtained with 10-mM glucose at 0.4 V with the designed bioanode. © 2019 John Wiley & Sons Ltd Daha fazlası Daha az

Macit, Hülya | Hazer, Baki

Article | 2004 | Journal of Applied Polymer Science93 ( 1 ) , pp.219 - 226

Combination of cationic, redox free radical, and thermal free radical polymerizations was performed to obtain linear and star polytetramethylene oxide (poly-THF)-polymethyl methacrylate (PMMA)/polystyrene (PSt) multiblock copolymers. Cationic polymerization of THF was initiated by the mixture of AgSbF6 and bis(4,4' bromo-methyl benzoyl) peroxide (BBP) or bis (3,5,3',5' dibromom-ethyl benzoyl) peroxide (BDBP) at 20°C to obtain linear and star poly-THF initiators with MW varying from 7,500 to 59,000 Da. Poly-THF samples with hydroxyl ends were used in the methyl methacrylate (MMA) polymerization in the presence of Ce(IV) salt at 40°C . . .to obtain poly(THF-b-MMA) block copolymers containing the peroxide group in the middle. Poly(MMA-b-THF) linear and star block copolymers having the peroxide group in the chain were used in the polymerization of methyl methacrylate (MMA) and styrene (St) at 80°C to obtain PMMA-b-PTHF-b-PMMA and PMMA-b-PTHF-PSt linear and star multiblock copolymers. Polymers obtained were characterizated by GPC, FT-IR, DSC, TGA, 1H-NMR, and 13C-NMR techniques and the fractional precipitation method. © 2004 Wiley Periodicals, Inc Daha fazlası Daha az

Macit, Hülya | Hazer, Baki | Arslan, Hülya | Noda, Isao

Article | 2009 | Journal of Applied Polymer Science111 ( 5 ) , pp.2308 - 2317

A new and promising method for the diversification of microbial polyesters based on chemical modifications is introduced. Poly(3-hydroxy alkanoate)-g-(poly(tetrahydrofuran)-b-poly(methyl methacrylate)) (PHAg-(PTHF-b-PMMA)) multigraft copolymers were synthesized by the combination of cationic and free radical polymerization. PHA-g-PTHF graft copolymer was obtained by the cationic polymerization of THF initiated by the carbonium cations generated from the chlorinated PHAs, poly(3-hydroxybutyrate-co-3- hydroxyvalerate) (PHBV), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHx) in the presence of AgSbF 6. Therefore, PHA-g-PTHF gr . . .aft copolymers with hydroxyl ends were produced. In the presence of Ce +4 salt, these hydroxyl ends of the graft copolymer can initiate the redox polymerization of MMA to obtain PHA-g-(PTHF-b-PMMA) multigraft copolymer. Polymers obtained were purified by fractional precipitation. In this manner, their ?-values (volume ratio of nonsolvent to the solvent) were also determined. Their molecular weights were determined by GPC technique. The structures were elucidated using 1H-NMR and FTIR spectroscopy. Thermal analyses of the products were carried out using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 2308-2317, 2009 Daha fazlası Daha az