Biyokimya/Makale Koleksiyonu

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https://hdl.handle.net/20.500.12395/15495

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Synthesis and evaluation of the antitumor activity of Calix[4]arene L-proline derivatives
(ACADEMIC PRESS INC ELSEVIER SCIENCE, 2020) Oguz, Mehmet.; Gul, Alev.; Karakurt, Serdar.; Yilmaz, Mustafa.
The unique conformational properties, functionality, low toxicity, and low cost make calixarene-based compounds a valuable candidate against cancer. The aim of the present study is the synthesis of the upper rim and lower rim-functionalized L-proline-based calix[4]arene derivatives and evaluation of their cytotoxic potential for human cancerous cells as well as to determine the death mechanism. Synthesized calix[4]arene (3, 8a, 8b 13a, and 13b) derivatives were characterized by different spectroscopic techniques such as (HNMR)-H-1, (CNMR)-C-13, and FTIR. In vitro effects of compounds 3, 8a, 8b, 13a and 13b were tested on human cancerous cells (HEPG2, PC-3, A-549, and DLD-1) as well as human healthy epithelium cell (PNT1A). Results show that compounds 3, 8a, 8b and 13b have cytotoxic potential on human colorectal carcinoma cells (DLD-1) with IC50, values of 43 mu M, 45.2 mu M, 64.57 mu M, and 29.35 mu M respectively. Apoptosis ratios of cell death were investigated with flow cytometer using 7-AAD and Annexin-V as markers. Cytotoxic potential of 8a was found to be higher due to increased apoptosis, when compared with healthy cells the apoptotic cell death was significantly (p < 0.0001) increased up to 1.7-fold and 2.4-fold in DLD-1 and A549 cells, respectively. In conclusion, these L-proline derived calix[4]arenes with their selective cytotoxic potential on human cancerous cells may be a potential candidate for the treatment of human CRC and lung cancer.
Synthesis of novel tetrazine based D-pi-A organic dyes for photoelectrochemical and photocatalytic hydrogen evolution
(ELSEVIER SCIENCE SA, 2020) Aslan, Emre.; Karaman, Merve.; Yanalak, Gizem.; Bilgili, Hakan.; Can, Mustafa.; Ozel, Faruk.; Patir, Imren Hatay.
Two novel donor-pi-acceptor (D-pi-A) dyes, called as MK-2 and MK-8, are synthesized. Their structural, optical and electrochemical properties are investigated by NMR, absorption/photoluminescence spectroscopies and cyclic voltammetry techniques, respectively. Photocatalytic and photoelectrochemical hydrogen evolution properties of these D-pi-A dyes are explored by using triethanolamine (TEOA) as a sacrificial electron donor under anaerobic conditions and visible light irradiation with or without co-catalysts (Cu2WS4 and Pt) for the first time. Photoelectrochemical and photocatalytic hydrogen evolution reaction (HER) activities of these dyes are studied by using TiO2 coated FTO electrodes and powdered TiO2 (Degussa P25), respectively. Photoelectrochemical response of MK-2/TiO2 and MK-8/TiO2 are figured out in the order of 180 mu A cm(-1) and 80 A cm(-1). The photocatalytic hydrogen evolution amounts of MK-2/TiO2, MK-2/TiO2/Cu2WS4, MK-2/TiO2/Pt, MK-8/TiO2, MK-8/TiO2/Cu2WS4 and MK-8/TiO2/Pt are turned out to be 565, 920, 1828, 374, 522 and 1260 mu molg(-1) h(-1), respectively. Dye/TiO2 photocatalysts are displayed good stability in the both photochemical HER experiments. The alteration in the HER activities of MK-2 and MK-8 is explained by molecule structures of dyes. The proposed mechanism of photocatalytic hydrogen evolution is clarified by using electrochemical band levels of each constituent.
Green preparation of Carbon Quantum dots using Gingko biloba to sensitize TiO2 for the photohydrogen production
(ELSEVIER SCI LTD, 2020) Genc, Munevver Tuna.; Yanalak, Gizem.; Arslan, Gulsin.; Patir, Imren Hatay.
Carbon Quantum dots (CQDs) were obtained from Gingko biloba by using microwave technique, which is easy, time-saving, cost-effective, non-toxic and environmental friendly way. TiO2 were sensitized by green-prepared CQDs to obtain CQDs/TiO2 composite. The characterizations of the CQDs and CQDs/TiO2 were performed by Transmission Electron Microscopy (TEM), high-resolution TEM (HR-TEM), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopic (XPS), Photoluminescence (PL) and Fourier Transformed Infrared (FT-IR) spectroscopy. The photocatalytic hydrogen evolution activity of CQDs/TiO2 system was studied under visible light (lambda > 420 nm) irradiation in the aqueous solution by using triethanolamine (TEOA) as a sacrificial electron donor. When Pt was used as a co-catalyst, CQDs/TiO2/Pt exhibited improved hydrogen evolution rate (1502 mu mol h(-1)g(-1)) compared to CQDs/TiO2 composite (665 mu mol h(-1)g(-1)).
Co-catalyst-free photocatalytic hydrogen evolution by Laponite D clay
(ELSEVIER SCIENCE SA, 2020) Aslan, Emre.
Laponite D is known as a zwitterionic synthetic clay having disc-shaped with negatively charged top faces and positively charged lateral edges, which is photochemically inactive and used to increase catalytic active surfaces. Herein, photocatalytic hydrogen evolution over Laponite D, which known as low cost inorganic clay, is firstly reported in a system containing Eosin-Y (EY) and triethanolamine (TEOA) as a photosensitizer and electron donor, respectively, under visible light illumination. This reaction system shows excellent stability due to the good charge transport and separation efficiency thanks to zwitterionic property of Laponite D.
Formation of the inclusion complex of water soluble fluorescent calix[4]arene and naringenin: solubility, cytotoxic effect and molecular modeling studies
(Taylor and Francis Ltd., 2019) Oğuz, Mehmet; Bhatti, Asıf Ali; Doğan, Berna; Karakurt, Serdar; Durdagı, Serdar; Yılmaz, Mustafa
Naringenin is considered as an important flavonoid in phytochemistry because of its important effect on cancer chemoprevention. Unfortunately its poor solubility has restricted its therapeutic applications. In this study, an efficient water-soluble fluorescent calix[4]arene (compound 5) was synthesized as host macromolecule to increase solubility and cytotoxicity in cancer cells of water-insoluble naringenin as well as to clarify localization of naringenin into the cells. Complex formed by host–guest interaction between compound 5 and naringenin was analyzed with UV–visible, fluorescence, FTIR spectroscopic techniques and molecular modeling studies. Stern–Volmer analysis showed binding constant value of Ksv 3.5 × 107 M?1 suggesting strong interaction between host and guest. Binding capacity shows 77% of naringenin was loaded on compound 5. Anticarcinogenic effects of naringenin complex were evaluated on human colorectal carcinoma cells (DLD-1) and it was found that 5-naringenin complex inhibits proliferation of DLD-1 cells 3.4-fold more compared to free naringenin. Fluorescence imaging studies show 5-naringenin complex was accumulated into the cytoplasm instead of the nucleus. Increased solubility and cytotoxicity of naringenin with fluorescent calix[4]arene makes it one of the potential candidates as a therapeutic enhancer. For deep understanding of host–guest interaction mechanisms, complementary multiscale molecular modeling studies were also carried out. Communicated by Ramaswamy H. Sarma. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.
The investigation of novel D-pi-A type dyes (MK-3 and MK-4) for visible light driven photochemical hydrogen evolution
(ELSEVIER SCI LTD, 2019) Aslan, Emre.; Karaman, Merve.; Yanalak, Gizem.; Can, Mustafa.; Ozel, Faruk.; Patir, Imren Hatay.
Two novel donor-n-acceptor (D-pi-A) semiconductor organic dyes have been synthesized for the photochemical hydrogen evolution reaction (HER) to sensitize TiO2 for the first time. The molecular structures of D-pi-A semiconductor organic dyes, which are entitled as MK-3 and MK-4, have been characterized by NMR spectroscopy method; and also electrochemical and optical properties have been investigated by cyclic voltammetry and UV-Vis absorption techniques, respectively. Amount of dye loading on TiO2 surface has been investigated by EDX method. The HER activities have been explored in the presence of triethanolamine (TEOA) as a electron donor reagent under sunlight (solar simulator illumination limited by cut-off filter lambda >= 420 nm) in the absence and presence of co-catalysts (Pt and Cu2WS4). Transient photocurrent densities of MK-3/TiO2 and MK-4/TiO2 electrodes have been reached to 110 mu A cm(-1) and 275 mu A cm(-1), respectively. The photocatalytic HER activities have been relatively enhanced in the presence of the Pt or Cu2WS4 co-catalysts (dye/TiO2/Cu2WS4 or dye/TiO2/Pt) when compared to only dye/TiO2. The HER rates have been found as 427, 1277, 675, 682, 1027 and 795 mu molg(-1) h(-1) for the MK-3/TiO2, MK-3/TiO2 /Pt, MK-3/TiO2/Cu2WS4, MK-4/TiO2, MK-4/TiO2/Pt and MK4/TiO2/Cu2WS4 , respectively. The differences of photochemical activities of MK-3/TiO2 and MK-4/TiO2 have been stated taking into account dye molecule structures. Moreover, the HER mechanism have been described by using electrochemical band energy levels of dyes, TiO2 and Cu2WS4 co-catalyst.
Production of magnetic chitinous microcages from ephippia of zooplankton Daphnia longispina and heavy metal removal studies
(ELSEVIER SCI LTD, 2019) Sargin, Idris; Arslan, Gulsin; Kaya, Murat
This is the first study on production of three dimensional chitinous microcages from ephippial eggs of a microcrustacean, Daphnia longispina (water flea) by keeping the original shape of its chitinous structure. Iron-based magnetic particles were successfully loaded into the chitinous microcages to enhance its heavy metal sorption capacity. The FT-IR, SEM-EDX and TGA analysis proved the purity of chitin and demonstrated that the loading of magnetic particles into the chitinous microcages was achieved. These newly obtained three-dimensional chitin microcages and magnetic particles loaded microcages were tested in Cd(II), Cr(III), Cu(II), Ni(II) and Zn(II) removal from aqueous solutions. Magnetic particles loaded microcages exhibited a better performance in removal of Cd(II), Cu(II) and Ni(II) ions; while unloaded microcages showed a higher affinity for Cr(III) and Zn(II). This study demonstrated that the chitin microcages are suitable carriers for iron-based magnetic particles. Here these new materials were studied only for removal of five heavy metal ions but these promising materials have a potential to be used in various fields.
Hexavalent chromium removal by magnetic particle-loaded micro-sized chitinous egg shells isolated from ephippia of water flea
(ELSEVIER SCIENCE BV, 2019) Arslan, Gulsin; Sargin, Idris; Kaya, Murat
Modified chitin and magnetic particles are two important materials widely used in heavy metal removal studies. Loading of magnetic particles into conventional adsorbents has emerged as a recent convenient way to improve the properties of adsorptive materials. Compared to its deacetylated form chitosan, chitin has very limited use in removal of contaminants because of its insolubility in aqueous environments. This study reports an easy way to produce micro-sized chitin and gives details on loading of magnetic particles into micro-sized chitin to enhance the interaction of chitin with heavy metal contaminant; hexavalent chromium Cr(VI). Removal of Cr(VI) ions from the aquatic environments is of high importance considering its detrimental effects on human health. Chitin microcages that had been isolated from the ephippial eggs of Daphnia longispina (crustacean, water flea) were incorporated with magnetic particles. Chitin microcages and magnetic particles-loaded chitin microcages were tested in removal of Cr(VI) under different solution and operational parameters; adsorbent dosage, contact time, Cr(VI) ion concentration, pH and temperature. Magnetic particles-loaded chitin microcages yielded higher Cr(VI) removal performance under all the specified conditions; chitin microcages: 0.77 mmol/g and particles loaded chitin microcages: 1.29 mmol/g. (C) 2019 Elsevier B.V. All rights reserved.
Green synthesized carbon quantum dots as TiO2 sensitizers for photocatalytic hydrogen evolution
(PERGAMON-ELSEVIER SCIENCE LTD, 2019) Sargin, Idris.; Yanalak, Gizem.; Arslan, Gulsin.; Patir, Imren Hatay.
Carbon quantum dots (CQDs) have attracted growing interest due to their superior luminescent properties, which make them excellent photosensitizers for TiO2. This study presents the green-synthesis of CQDs from edible mushroom Agaricus bisporus through microwave irradiation. In the study as-synthesized CQDs were used as a sensitizer for TiO2 in photocatalytic hydrogen evolution in aqueous triethanolamine (sacrificial reagent) under visible-light irradiation. Photocatalytic hydrogen production activity of CQD-sensitized TiO2 was found to be 472 mu mol g(-1) h(-1) (without loading any noble metal co-catalyst) and 1458 mu mol g(-1) h(-1) (with loading Pt co-catalyst). The study revealed that the CQDs from mushroom A. bisporus can be used as an efficient sensitizer for TiO2 in photocatalytic hydrogen production. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Encapsulation of lipase using magnetic fluorescent calix[4]arene derivatives; improvement of enzyme activity and stability
(ELSEVIER SCIENCE BV, 2019) Ozyilmaz, Elif.; Cetinguney, Sevilay.; Yilmaz, Mustafa.
In this study, iron magnetic nanoparticles capped with fluorescent calixarene derivatives (Fe3O4@Calix-2 and Fe3O4@Calix-3) were prepared in one-step using coprecipitation of Fe(II) and Fe(III) in basic solution. Different techniques were used to characterize the synthesized magnetic nanoparticles, such as Fourier Transform Infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and confocal microscopy. Candida rugosa was encapsulated on synthesized nanoparticles following sol-gel method. It has been observed that under the optimum conditions, the activity of encapsulated lipase (Fe3O4@Calix-2E) was 119 U/g of support which is 4.1 times more that of the encapsulated lipase without calix[4]arene derivative (Fe3O4@E). Comparative study show that the encapsulated lipase on nanoparticles has higher thermal and operational stability than encapsulated lipase without calix[4]arene derivative. Among these encapsulated lipase nanoparticles, Fe3O4@Calix-2 was capable of effectively catalyze hydrolysis of racemic Flurbiprofen methyl ester with high conversion of 49% and substrate enantiomeric excess (ees) of 85% at optimum pH and temperature. The efficiency of these nanoparticles was assessed by their reusability, for that after five consecutive operational uses these encapsulated lipase nanoparticles retained their conversion ratios up to 38% and 30% respectively, in the hydrolysis of (R,S)-Flurbiprofen methyl ester. The results showed that encapsulated lipases nanoparticle with calixarene moieties lead to increased activity, stability, reusability and enhanced stereoselectivity in kinetic resolution. (C) 2019 Elsevier B.V. All rights reserved.
Donor-pi-acceptor dye-sensitized photoelectrochemical and photocatalytic hydrogen evolution by using Cu2WS4 co-catalyst
(PERGAMON-ELSEVIER SCIENCE LTD, 2019) Patir, Imren Hatay.; Aslan, Emre.; Yanalak, Gizem.; Karaman, Merve.; Sarilmaz, Adem.; Can, Mumin.; Can, Mustafa.; Ozel, Faruk.
Photoelectrochemical and photocatalytic hydrogen evolution reaction (HER) have been investigated by using metal free donor-acceptor (D-A) and donor-pi-acceptor (D-pi-A) dyes, which are abbreviated as MC-32 and MC-048, respectively, sensitized TiO2 as a photo-catalyst with or without Cu2WS4 co-catalyst. This co-catalyst is synthesized by a low-cost and simple hot injection method, under visible light illumination. The photoactivities of these dyes have been clarified according to their structural, optical and electrochemical properties. Photocatalytic activities have been slightly increased when added the Cu2WS4 co-catalyst (dye/TiO2/Cu2WS4). This catalytic activity is also compared to that of noble metal Pt (dye/TiO2/Pt). It has been found that 121 mu molg(-1)h(-1), 179 mu molg(-1)h(-1), 348 mu molg(-1)h(-1), 212 mu molg(-1)h(-1), 422 mu molg(-1)h(-1) and 1139 mu molg(-1)h(-1) hydrogen have been evolved by using MC-32/TiO2, MC-32/TiO2/Cu2WS4, MC-32/TiO2/Pt, MC-048/TiO2, MC-048/TiO2/Cu2WS4 and MC-048/TiO2/Pt, respectively. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Cu(II) sorption performance of silane-modified poly(NaSS-co-MA-co-AAm) and poly(NaSS-co-MA-co-NIPAM) terpolymers
(SPRINGER, 2019) Okudan, Ahmet.; Ozviran, Emre.; Arslan, Gulsin.; Sargin, Idris.
This study reports the adsorption of Cu(II) ion by 3-(2-aminoethylamino) propyldimethoxymethylsilane-modified terpolymers. Water-soluble poly(sodium 4-styrenesulfonate-co-maleic anhydride-co-acrylamide) [poly(NaSS-co-MA-co-AAm)] and poly(sodium 4-styrenesulfonate-co-maleic anhydride-co-N-isopropylacrylamide) [poly(NaSS-co-MA-co-NIPAM)] terpolymers were synthesized and then modified with silane to make them water-insoluble. H-1-NMR and FT-IR spectroscopy was used to study the chemical composition of the terpolymers. Also, acid number and viscosity of the polymers were determined. Cu(II) ion adsorption parameters (adsorbent dosage, contact time, pH and metal ion concentration) were studied, and the equilibrium data were evaluated using adsorption isotherm models; Freundlich isotherm gave the best fit. Cu(II) adsorption performance of poly(NaSS-co-MA-co-AAm) and poly(NaSS-co-MA-co-NIPAM) terpolymers was found to be 53.42 and 43.10%, respectively. The terpolymers can be used for removal of Cu(II) from aqueous media.
Cu(II) sorption performance of novel chitosan/ter-(vinyl pivalate-maleic anhydride-N-tert-butylacrylamide) microcapsules
(SPRINGER, 2019) Okudan, Ahmet.; Ataoglu, Busra Ebru.; Sengoz, Onur.; Arslan, Gulsin.
In this study, first, the ter-polymerization reaction between vinyl pivalate (VP), maleic anhydride (MA), and N-tert-butylacrylamide (NTBA) was done in inert atmosphere (N-2). FT-IR and (HNMR)-H-1 spectroscopy was applied to study the chemical composition of the obtained ter-polymers. MA content of the ter-polymers was determined by following the chemical titration method. Second, novel chitosan/ter-(vinyl-pivalate-maleic-anhydride-N-tert-butylacrylamide) microcapsules were synthesized. In microcapsule production, chitosan polymer served as a matrix for acrylamide ter-polymers with four different molar ratios. The microcapsules were characterized by FT-IR and SEM analyses. Cu(II) sorption efficiency of the microcapsules were tested at different pH levels, temperature, sorbent dosage, and metal ion concentration. Comparison with blank chitosan microbeads revealed that incorporation of acrylamide ter-polymers into the cross-linked chitosan matrix increased the metal sorption. Sorption capacities of the sorbents were recorded; blank chitosan microbeads: 67.03 mg g(-1), and chitosan/acrylamide ter-polymer microcapsules: in range of 75.39-98.64 mg g(-1). The findings demonstrated chitosan/acrylamide ter-polymer microcapsules can be utilized in sorption of Cu(II) ions in water treatment.
Characterisation of chitin in the cuticle of a velvet worm (Onychophora)
(TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY, 2019) Greven, Hartmut.; Kaya, Murat.; Sargin, Idris.; Baran, Talat.; Kristensen, Reinhardt Mobjerg.; Sorensen, Martin Vinther.
We characterize the trunk cuticle of velvet worms of the Peripatoides novaezealandiae-group (Onychophora) using SEM, TEM, Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). TEM and SEM revealed a relatively uniform organization of the delicate cuticle that is covered by numerous bristled and nonbristled papillae with ribbed scales arranged in transverse rows. The cuticle consists of a very thin multilayered epicuticle of varying appearance followed by the largely fibrous procuticle. The irregularly arranged nanofibres of isolated cuticular chitin seen by SEM are considered as bundles of chitin fibres. FT-IR and TGA showed that the chitin is of the alpha-type. This confirms and broadens the single previous study in which the presence of a-chitin in a velvet worm was demonstrated with a single analysis (X-ray diffraction).
Autoinhibitory feedback control over photodynamic action
(AMER CHEMICAL SOC, 2019) Yurt, Mediha Nur Zafer.; Cakmak, Yusuf.; Tekin, Gulsum.; Karakurt, Serdar.; Erbas-Cakmak, Sundus.
In biology, the activity of enzymes is usually regulated by feedback loops, which enables direct communication between enzymes and the state of the cell. In a similar manner, with the intention to have automated activity regulation, the therapeutic effect of a photosensitizer (BOD1) is shown to be reduced through a negative feedback loop initiated by the photosensitizer. Photodynamic action produces cytotoxic O-1(2) and this reactive oxygen species reacts with ascorbate, generating H2O2. Peroxide-mediated oxidation of the photosensitizer auxiliary group leads to the formation of inactive BOD2 from the parent photosensitizer. BOD1 is shown to accumulate in mitochondria, and cell viability is shown to decrease significantly with BOD1 compared to the loop end product, BOD2. Photoinduced enhancement of fluorescence indicates the formation of inactive BOD2 under cellular conditions, and enhanced fluorescence acts as a reporter for the activity of the photosensitizer. We present the first example of PDT autoinactivation, and such a feedback control mechanism would enable a decrease in post-therapy side effects.
Characterization of chitosan-based films with different aniseed oil content
(2018) Yılmaz, Bahar Akyüz; Kaya, Murat; Akyüz, Lalehan; Çakmak, Yavuz Selim; Erkul, Seher Karaman; Sargın, İdris; Koç, Behlül
This paper reports the findings of a study describing the production of chitosan-based edible films incorporated with different amount of Pimpinella anisum seed oil. The chitosan-aniseed oil (CAO) composite films (CS, CAO-0.5, CAO-1, and CAO-2) were characterized with FT-IR and DSC and their mechanical, optical transmittance, hydrophobicity and anti-oxidative properties were also investigated. With the increasing concentration of aniseed oil in the films, a continuous decrease was observed in tensile strength and Young’s modulus. Optical transmittance of chitosan-aniseed oil composite films in the UV-Visible region was lower than that of chitosan control film (without aniseed oil). Incorporation of aniseed oil into chitosan films enhanced antioxidant activity of films. The results suggested that chitosan-aniseed oil composite films can be used as a food packaging material.
N-Acetylcysteine Prevents Vasospasm After Subarachnoid Hemorrhage
(ELSEVIER SCIENCE INC, 2010) Güney, Önder; Erdi, Fatih; Esen, Hasan; Kıyıcı, Aysel; Kocaoğullar, Yalçın
Background: This study investigated the ability of NAC to prevent cerebral vasospasm in a rabbit model of SAH. Methods: Twenty-one, male New Zealand white rabbits were randomly divided into 3 groups of 7 rabbits each: group 1 (control), group 2 (SAH only), group 3 (SAH + NAC treatment). NAC (150 mg/kg, single dose, IF) was administered just before SAH and continued until 72 hours after SAH in group 3. Animals were killed 72 hours after SAH. Tissue MDA levels, SOD, and GSH-Px activities were measured, and basilar artery cross-sectional areas, arterial wall thickness, and endothelial apoptosis in a cross section of basillary artery were determined in all groups. Results: Intraperitoneal administration of NAC was found to be. markedly effective against developing a cerebral vasospasm following a SAH in rabbits. It could significantly reduce elevated lipid peroxidation and increase the level of tissue GSH-Px and SOD enzymatic activities. Also, NAC treatment was found to be effective in increasing the luminal area and reducing wall thickness of the basilar artery. The morphology of arteries in the NAC treatment group was well protected. NAC markedly reduced apoptotic index and protects the endothelial integrity. Conclusions: This study demonstrates, for the first time, that NAC treatment attenuates cerebral vasospasm in a rabbit SAH model. NAC treatment has significant neuroprotective effect and markedly prevents cerebral vasospasm after SAH. In conclusion, the NAC treatment might be beneficial in preventing cerebral vasospasm after SAH, thus showing potential for clinical implications.
The Effect of Prophylactic Melatonin Administration on Reperfusion Damage in Experimental Testis Ischemia-reperfusion
(Maghira & Maas Publications, 2003) Öztürk, Ahmet; Baltacı, Abdulkerim Kasım; Moğulkoç, Rasim; Öztürk, Bahadır
AIM: Torsion of testis, which is a urologic emergency case, is generally treated by surgical detorsion procedure. However, the resulting reperfusion and both ipsilateral and contralateral testis damage caused thereby are important problems. This study aims at investigating the administration of prophylactic melatonin in order to reduce free radical damage that is caused due to reperfusion after experimental testis torsion-detorsion procedure. MATERIAL AND METHOD: The rats used in the study were allocated to four groups, each containing 10 rats. Rats in Group I had six hours of torsion (ischemia) followed by orchiectomy. Rats in Group II had six hours of torsion, then received melatonin (10 mg/kg/IM) and after that had detorsion (reperfusion). Rats in Group Ill had detorsion after six hours of torsion and serum physiologic administration (the same volume as melatonin). Torsion and/or detorsion procedures were not applied in Group IV (control). Ipsilateral, contralateral testis and plasma Malondialdehyde (MDA) levels were determined in all groups. RESULTS: Tissue and plasma MDA levels in the group which had detorsion were found to be significantly higher than those in the group that had orchiectomy only (p < 0.02). Ipsilateral and contralateral testis MDA levels were identified to be significantly lower in the group receiving prophylactic melatonin in comparison to the group receiving serum physiologic (p < 0. 02). Plasma and contralateral MDA levels correlated positively with MDA levels identified in ipsilateral testis in all groups (rs= +0.89, n=40, p=0.000). CONCLUSION: In cases where testis torsion is identified, administration of melatonin just before torsion may reduce local and systemic free radical damage.
Effects of Zinc Deficiency and Supplementation on Malondialdehyde and Glutathione Levels in Blood and Tissues of Rats Performing Swimming Exercise
(Humana Press Inc, 2003) Öztürk, Ahmet; Baltacı, Abdülkerim Kasım; Moğulkoç, Rasim; Öztekin, Esma; Sivrikaya, Abdullah; Kurtoğlu, Erdal; Kul, Aylin
The aim of the study was to investigate the effects of zinc deficiency and supplementation on lipid peroxidation and glutathione levels in blood and in some tissues of rats performing swimming exercise. Forty adult male Sprague-Dawley rats were divided into four groups: group 1, zinc-deficient consisted of swimming rats; group 2 consisted of zinc-supplemented swimming rats; groups 3 and 4 were the swimming and nonswimming controls, respectively. The levels of malondialdehyde and glutathione were measured after 4 wk of zinc-deficient or zinc-supplemented diet and 30 min of swimming exercise daily. The erythrocyte glutathione levels of groups 2 and 4 were significantly higher than those of groups 1 and 3 (p<0.01). The plasma malondialdehyde level of group 1 was significantly higher than all other groups. The glutathione levels in liver, kidney, striated muscle, and testes of group 2 were higher than in the other groups (p<0.01) and higher in kidney and striated muscle of group 3 than in groups 1 and 4 (p<0.01). The tissue malondialdehyde levels of striated muscle, liver, kidney, and testes of group 1 were significantly higher than for all other groups (p<0.01). Our findings suggest that both swimming exercise and zinc deficiency result in an increase of lipid peroxidation in tissues and that zinc supplementation prevents these alterations by the activation of the antioxidant system.
Effects of Magnesium Sulfate on Tissue Lactate and Malondialdehyde Levels After Cerebral Ischemia
(Karger, 2003) Barışkaner, Hülagü; Üstün, M. E.; Ak, A.; Yosunkaya, Alper; Ulusoy, H. B.; Gürbilek, Mehmet
In the present study, the effects of magnesium sulfate on tissue lactate and malondialdehyde (MIDA) levels after cerebral ischemia in rabbits were studied. The rabbits were divided equally into three groups. Group 1 (n = 8) was the sham-operated control group, in group 2 (n = 8) only cerebral ischemia was induced by clamping bilaterally the common carotid arteries for 60 min, and in group 3 (n = 8) magnesium sulfate was administered at a dose of 100 mg/kg im. within 5 min after opening the clamps. In group 1 EEG recordings were obtained immediately and 60 and 120 min after craniectomy. In groups 2 and 3 EEG recordings were obtained immediately after craniectomy but before clamping and 60 min after clamping. One hour after opening the clamps and taking EEG recordings, brain cortices were resected, and the concentrations of lactate and MIDA were determined using spectrophotometric/enzymatic and thiobarbituric acid methods, respectively. In all groups, there were significant differences between MDA and lactate levels (p < 0.05). There were no significant differences in lactate levels between groups 2 and 3 (p > 0.05), and also the preischemic EEG grades were the same in all groups. Preischemic and postischemic EEG values were significantly different (p < 0.05), and there were also significant differences between postischemic EEG grades in groups 2 and 3 (p < 0.05). There was a correlation between postischemic EEG grades and MIDA and lactate levels. These results demonstrate that cerebral ischemia-reperfusion injury leads to an increase in brain tissue lactate and MIDA levels, that magnesium sulfate suppresses the increase of MDA and lactate concentrations, and that magnesium sulfate, treatment improves the EEG changes. The EEG grades correlated well with MIDA and lactate levels.

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