Objective: It is known that point mutations, duplications and deletions occur in mitochondrial DN... more Objective: It is known that point mutations, duplications and deletions occur in mitochondrial DNAs (mtDNA) of different tissues of individuals. Among the deletions observed, mt4977 mutation, which is located at nucleotide positions 8470-8482 and 13447-13459 and causes the loss of 4977 base pairs, is the most common. mtDNA 4977 deletion leads to the loss of 8 genes encoding subunits of respiratory chain complexes. Consequently, the deletion could be expected to inhibit the oxidative function and reduce ATP production level. It is known that mitochondrial ATP production has an important role on platelet functions. However, there is no information about this in the literature. Since platelet activation in ischemic heart disease (IHD) has been shown to play an important role in the pathophysiology of the disease, we wanted to examine the relationship between platelet function and mtDNA 4977 deletion in ischemic heart disease. Material and Method: Platelet functions were studied by giving ADP stimulus with the help of lumiaggregometer device to evaluate in terms of secretion and aggregation. ATP measurement was performed with the bioluminescence assay kit. mtDNA 4977 deletion was determined by the modified simultaneous quantitative polymerase chain reaction method. Results: The frequency of mtDNA 4977 deletion and mtDNA copy number were higher in platelets of the patients compared with the healthy control group (p<0.05). However, no significant differences in platelet ATP content, and in their slope (Ω) and % amplitude values were observed between both groups (p>0.05). Conclusion: It was observed that increased deletion in patients with IHD did not have a significant effect on platelet dysfunction compared with healthy control subjects. ÖZET Amaç: Bireylerin farklı dokularındaki mitokondriyal DNA'larında (mtDNA) nokta mutasyonları, duplikasyonlar ve delesyonlar meydana geldiği bilinmektedir. Gözlenen delesyonlar içerisinde 8470-8482 ile 13447-13459 nükleotid pozisyonlarında yer alan ve 4977 baz çiftinin kaybına yol açan mtDNA 4977 mutasyonu en sık olarak görülmtedir. mtDNA 4977 delesyonu solunum zinciri komplekslerinin alt ünitlerini kodlayan 8 genin kaybolmasına yol açar. Buna bağlı olarak delesyonun oksidatif fonksiyonu engellemesi ve ATP üretim düzeyini azaltması beklenebilir. Mitokondriyal ATP üretiminin trombosit fonksiyonları üzerinde önemli bir rolü olduğu bilinmektedir. Ancak bununla ilişkili olarak literatürde herhangi bir bilgi göze çarpmamaktadır. İskemik kalp hastalığında (İKH) trombosit aktivasyonunun hastalık fizyopatolojisinde önemli bir rol oynadığı gösterildiğinden, bu çalışmamızda trombosit fonksiyonu ile mtDNA 4977 delesyonu arasındaki ilişkiyi ve iskemik kalp hastalığı gelişimindeki olası etkilerini araştırmayı amaçladık. Gereç ve Yöntem: Trombosit fonksiyonları, sekresyon ve agregasyon açısından değerlendirilmek üzere lumiagregometre cihazı yardımı ile ADP uyaranı verilerek çalışıldı. ATP ölçümü biyolüminesans test kiti ile yapıldı. mt4977 delesyonu, modifiye edilmiş eşzamanlı kantitatif polimeraz zincir reaksiyonu (RT-PCR) yöntemi ile belirlendi. Bulgular: Hastaların trombositlerinde mtDNA 4977 delesyon sıklığı ve mtDNA kopya sayısı sağlıklı kontrol grubuna göre daha yüksekti (p <0.05). Ancak her iki grup arasında trombosit ATP içeriği ile bunların eğim (Ω) ve % amplitüd değerlerinde anlamlı farklılık gözlenmedi (p> 0.05). Sonuç: Sağlıklı kontrol denekleriyle karşılaştırıldığında, İKH hastalarında artmış delesyonun trombosit disfonksiyonu üzerinde anlamlı bir etkiye sahip olmadığı görülmüştür.
It is known that erythrocyte aggregation in renal tissue during preserva- tion is cause of microc... more It is known that erythrocyte aggregation in renal tissue during preserva- tion is cause of microcirculation defects in the reperfusion period. The aim of our study is to investigate oxidative damage in erythrocytes relative to the time of cold ischemia during organ preservation and relationship between lipid peroxidation and development of these damages. In experiments with a rabbit model, explant- ed kidneys were exposed to perfusion and 96 hours preservation with Euro-Collins (EC) in the 1st group, and University of Wisconsin (UW) solution in the 2nd group. Electron- microscopic examinations in renal tissues were performed. Lipid peroxidation and glu- tathione levels in erythrocytes preserved in the same solutions were investigated. Agglutination of the erythrocytes and adhe- sion to the endothelium with ‡24 hours preservation were observed in the kidney tis- sue of the first group, and after ‡48 hours preservation in the second group. During preservation of the erythrocytes in or...
Object. Thyroid cancer (TC) is a rare type of cancer which occurs as a result of environmental an... more Object. Thyroid cancer (TC) is a rare type of cancer which occurs as a result of environmental and genetic factors. Although different types of genetic and epigenetic changes are associated with TC, the molecular mechanism still remains unclear. SRY-box transcription factor 15 (SOX15) is an important transcription factor, and its expression is altered in many cancer types by epigenetic modifications. Recently, miR-147b overexpression has been associated with SOX15 silencing in TC. Methods. In this study, qRT-PCR was used to investigate the expression levels of the SOX15 gene and of miR-182, miR-183, miR-375, and miR-96 in thyroid tumors and adjacent noncancerous tissues. We also investigated the methylation status of the SOX15 promoter by methylation-specific PCR in tumors and adjacent noncancerous tissues. Results. We observed a statistically significant downregulation of SOX15 expression in tumors compared to noncancerous tissue samples. The methylation levels of tumors and matche...
The extract from larval Lucilia sericata is used clinically to promote wound healing and tissue r... more The extract from larval Lucilia sericata is used clinically to promote wound healing and tissue regeneration. However, its effect and underlying mechanisms on fibroblast cells, which are involved in the wound healing process, are still poorly understood. This study aimed to examine the effects of larval secretions on dermal fibroblast activity and gene expression and to evaluate the wound healing potential of their major components. Primary rat fibroblasts were cultured and treated with larval secretions. Following the treatment, the cells were used to extract RNA for gene profiling. In addition, migration to the injury site was studied with the scratch healing assay. Our results showed that larval secretion accelerated the migration of the fibroblasts compared to the control cells and that several mRNAs were differentially expressed during a period of 72 h incubation. Additionally, we analyzed the chemical composition of larval secretions and showed that fumaric acid, ferulic acid, and p-coumaric acid, which were selected and identified for their major components, enhanced the migration of the fibroblasts. Therefore, these results indicate that L. sericata larval secretions could modulate the mRNA expression of some wound healing-related genes of the fibroblasts and contain the effective components for wound healing.
Normal wound healing is achieved by a cascade of many cellular activities. This process is affect... more Normal wound healing is achieved by a cascade of many cellular activities. This process is affected by some of the metabolic diseases like Diabetes Mellitus (DM). DM causes bad prognosis and is one of the major contributors to chronic wound healing problems. Recently, Lucilia sericata larvae are used for wound healing as they are very effective agents in wound healing process. It's still unclear that how the larvae affect the molecular mechanisms and signaling pathways of chronic wound healing. MicroRNAs (miRNAs) can induce gene expression in post-transcriptional mechanisms. In this study, our aim was to determine whether the larvae secretions could change the expression patterns of selected miRNAs on the diabetic microenvironment. Methods: Wistar Albino rats were classified as diabetic and nondiabetic, then full thickness cutaneous wounds were created at the dorsal region of rats. Wound tissues were collected on days 0, 3, 7 and 14 post wounding. The association between miR21, miR146a, miR146b and miR29a gene expression profiles and wound healing Amaç: Normal yara iyileşmesi bir çok hücresel faaliyetin zincirleme tepkimeleri ile gerçekleşmektedir. Diabetes Mellitus gibi metabolik hastalığa sahip kişilerde ise bu süreç olumsuz etkilenmekte, kötü iyileşen ya da iyileşmeyen kronik yaraların meydana gelmesine neden olmaktadır. Lucilia sericata larvalarının yara iyileşmesinde etkin rol oynamakta olduğu bildirilmiştir ancak kronik yara iyileşmesinin moleküler mekanizmasında ve ilgili yolaklardaki etkileri hala bilinmemektedir. RNA türlerinden biri olan mikroRNA'ların (miRNA) bir bölümünün yüksek glukoz düzeylerinde ekspresyonlarının değiştiği gösterilmiştir. Bu sebeple çalışmamızda; yara iyileştirmesinde rolü olduğu bildirilen bazı miRNA'ların ekspresyonlarının diyabetik şartlarda larva salgısı uygulaması ile deri iyileşmesi süresince ne yönde etkilendiği incelenmiştir. Yöntemler: Deneysel çalışmamızda kullanılan Wistar Albino türü sıçanlar diyabetik ve diyabetik olmayanlar olarak gruplandırıldıktan sonra sırt bölgesinde tam kat yara oluşturulmuştur. Oluşturulan yara bölgelerinden 0., 3., 7. ve 14. günlerde biyopsi örneği alınmıştır. Çalışmamızda literatür taraması yapılarak yara iyileşmesi ile ilişkilendirilmiş miR21, miR146a, miR146b ve miR29a genlerinin
Some anesthetics including ketamine/xylazine and thiopental have been shown to alter the expressi... more Some anesthetics including ketamine/xylazine and thiopental have been shown to alter the expression of genes related with inflammatory cytokines and chemokines in previous studies unassociated with wound healing, arising the question of whether commonly used anesthetics in wound healing models could interfere with the transcriptional responses of the genes associated with skin wound healing. The gene expression profile in wound biopsies of rats who received widely used anesthetics doses of intraperitoneal ketamine/xylazine (50 mg/kg and 10 mg/kg) or thiopental (50 mg/kg) in comparison with control rats was analyzed by monitoring the expression of genes effective on various phases of wound healing. The expression levels of 84 genes were determined on 3rd, 7th and 14th days of post-wounding using a qPCR array system. Of the genes either up or downregulated fivefolds or more, three (Egf, Col5a1 and Cxcl3) and two (Tgfa and Il2) genes were found to be the most responsive ones to ketamine/xylazine or thiopental anesthesia respectively in a period of 14 days after correction for multiple testing. However, up to 22 and 24 genes for ketamine/xylazine and thiopental were found to be differentially expressed in the same period without correction for multiple-comparisons testing (p < 0.05). In conclusion, our data suggest that ketamine/xylazine and thiopental may alter the transcriptional responses of some genes associated with wound healing in rats. We strongly suggest to consider the possible alteration effect of these anesthetics on gene expression in animal models of dermal wound healing.
Turkish journal of haematology : official journal of Turkish Society of Haematology, Jan 5, 2002
To evaluate the role the coagulation and fibrinolysis abnormalities in the pathogenesis of ischem... more To evaluate the role the coagulation and fibrinolysis abnormalities in the pathogenesis of ischemic stroke of undetermined etiology, we assayed plasma concentration of fibrinopeptide-A and thrombin-antithrombin III complex, both sensitive markers for thrombin activation and fibrin formation, and D-dimer, a marker of plasmin activity and fibrinolysis. Hemostatic markers were measured in 32 patients with acute stroke and 20 patients with chronic stroke, and compared with 21 normal subjects. Fibrinopeptid-A and thrombin-antithrombin III complex levels were not elevated significantly, whereas the D-dimer level was markedly raised in acute (p< 0.001) and chronic (p< 0.05) phases of ischemic stroke in comparison with the control group. Prolonged elevation of D-dimer concentration suggests that hemostatic abnormalities have a primary role in the pathogenesis of ischemic stroke. The measurement of D-dimer concentration may help to better decide the indications for therapy of the patie...
To compare glutathione S-conjugate transport in obese and nonobese persons, and how glutathione S... more To compare glutathione S-conjugate transport in obese and nonobese persons, and how glutathione S-conjugates are involved in the antioxidant status in obesity. The efflux of glutathione conjugates and malondialdehyde (MDA) levels were measured in erythrocytes of obese (N = 33) and nonobese (N = 28) persons at every 30 min during a 120 min incubation time in vitro. 2,4-dinitrophenyl-S-glutathione (DNP-SG) represented the glutathione S-conjugate. The efflux of conjugate in erythrocytes from obese subjects (708 +/- 147 DNP-SG efflux nmol/ml erythrocytes/h) was significantly higher than that of control group (490 +/- 105 DNP-SG efflux nmol/ml erythrocytes/h) (P &lt; 0.05). At all time points measured (30-120 min), there was an increase in DNP-SG efflux in obese group (P &lt; 0.05). This is manifested by a decrease in cellular DNP-SG levels. The susceptibility of erythrocytes to in vitro 1-chloro-2,4-dinitrobenzene (CDNB)-induced oxidative stress were greater for cells of control group (P &lt; 0.05), although hemolysis sensitivity of these cells are not different between both groups (P &gt; 0.05). Following CDNB pretreatment, incubation of erythrocyte with vanadate, a DNP-SG transport inhibitor, resulted in an increase of MDA in both groups. However, in this case, the difference in susceptibility was not related to obesity. On the other hand, while erythrocyte glutathione level was lower in obese subjects (79% of control) than in controls (P &lt; 0.05), the adenosine 5&#39;-triphosphate (ATP) levels, the enzyme activities of glutathione S-transferase (GST) and the conjugation capacities of the erythrocytes were not different between groups (P&gt;0.05). Obesity may increase erythrocyte glutathione conjugate transport independent from ATP and GST activity that may protect against MDA formation in vitro.
Journal of Basic and Clinical Physiology and Pharmacology, 2006
The development of diabetic complications has usually been attributed to the nonenzymic glycation... more The development of diabetic complications has usually been attributed to the nonenzymic glycation of tissue proteins. Only recently, however, have researchers examined the possible role on free radicals in the pathogenesis of diabetes. In the present study, glutathione (GSH) and major antioxidant enzyme levels in plasma of patients with type II diabetes mellitus were assessed both before and after 3 months of N-acetylcysteine (NAC) therapy. Thirty-two diabetic patients were examined as well as fifteen healthy controls. Before treatment with NAC, glutathione peroxidase (GPx), catalase (CAT), and (GSH) levels of diabetic patients and control subjects showed no significant differences, whereas glutathione S-transferase (GST) levels were higher in type II diabetic patients. Following 3 months of Following NAC supplementation, GSH, GST, and CAT levels were found to be similar to the levels before treatment. On the other hand, GPx activity was significantly lower compared with the values before treatment. According to this finding, NAC treatment could have a positive effect on GPx values in type II diabetic patients showing abnormally high values.
The anti-epileptic drug vigabatrin was developed as an inhibitor of gamma-aminobutyric acid trans... more The anti-epileptic drug vigabatrin was developed as an inhibitor of gamma-aminobutyric acid transaminase, and its ability to increase inhibition in the central nervous system led to its testing in an animal model. In animal models chronic use of vigabatrin is associated with irreversible myelin vacuolation. Antioxidant drugs change the antioxidant capacity of the body. Oxidative stress of the body increased when valproic acid and carbamazepine were used chronically. To assess whether vigabatrin may affect protein oxidation and lipid peroxidation, glutathione, glutathione peroxidase (GPx), and glutathione-S-transferase (GST) levels were studied in the livers of 57 rat fetuses after administration of vigabatrin to the mothers (19 in the first week of pregnancy, 20 in the second week, and 18 in the third week) and in 19 control rat fetuses without vigabatrin. We compared the results of administration of vigabatrin in each group with the controls. Rat fetus protein oxidation in group I (0.686 nmol/mg protein) and group II (0.723 nmol/mg protein) was higher than in the control group (0.388 nmol/mg protein). Lipid peroxidation (0.209, 0.224, 0.253 nmol/mg protein, respectively) and GPx levels (345.4, 329.0, 283.2 nmol/mg protein, respectively) of groups I, II, and III were higher than in the control group (0.104, 167.2 nmol/mg protein, respectively). GST in group II (79.2 nmol/mg protein) and group III (77.8 nmol/mg protein) were not different from that in the control group (78 nmol/mg protein). It was found that vigabatrin affected all the parameters that were studied, especially in group I, which was given the drug in the first week of pregnancy.
Recent epidemiological studies proposed that the glutathione S-transferase (GST) M1-null genotype... more Recent epidemiological studies proposed that the glutathione S-transferase (GST) M1-null genotype may contribute to diseases associated with oxidative stress. The genetic polymorphism exhibited by the GSTM1 may be an important factor in risk toward oxidant chemicals. In this study, we investigated the e¡ect of GSTM1-null genotype in lymphocyte and oxidative stress-dependent inhibition of platelet aggregation. To determine whether GSTM1 de¢ciency is a genetic determinant of cell toxicity toward oxidant chemicals, lymphocytes were incubated in vitro with low levels of benzo(a)pyrene (BaP), cumene hydroperoxide (CumOOH), or trans-stilbene oxide that do not decrease cell viability, and were assessed for oxidative damage and for the lymphocyte-dependent inhibition of platelet response. Malondialdehyde and carbonyl levels, and the oxidation of cisparinaric acid, were used as biomarkers of oxidative stress in lymphocytes. Following stimulation by BaP or CumOOH, when peroxidation-dependent changes in these parameters were compared between the GSTM1-null genotype and the positive genotype, no signi¢cant di¡erences were found between the two genotypes. On the other hand, preincubation of the lymphocytes with BaP or CumOOH attenuated their inhibitory action on ADP-induced platelet aggregation. However, our results indicate that lymphocytes of individuals with the GSTM1-null genotype have greater inhibitory activity on platelet function after exposure to BaP, but not CumOOH, although they are not more susceptible to in vitro oxidative stress.
Objective: Paraoxonase-1 (PON1) is an HDL-associated enzyme implicated in the pathogenesis of ath... more Objective: Paraoxonase-1 (PON1) is an HDL-associated enzyme implicated in the pathogenesis of atherosclerosis by protecting lipoproteins against peroxidation. PON1 has two genetic polymorphisms both due to amino acid substitution, one involving glutamine and arginine at position 192 and the other leucineand methionine at position 55. Our study aimed to compare the effect of PON192 polymorphism and PON1 activity in patients with type 2 diabetes mellitus (T2DM) and non-diabetic controls. Material and Methods: 50 patients with T2DM and 30 non-diabetic controls were included in this study. The PON192 polymorphism was studied by polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP). Paraoxonase activity was measured by spectrophotometric method. Results: The frequencies of the QQ, QR and RR genotypes were found as 36.5 and 14% in type 2 diabetes patients and 26.67, 46.66, 26.67% in control subjects, respectively. The paraoxonase activity was detected at lower levels in diabetics (102.0 ±38.9) than in control subjects (158.1±63.7). PON1192 RR homozygotes had significantly higher PON activity than QR and QQ genotypes among control and type 2 diabetes patients (p<0.005). Conclusion: In comparing the activities of three genotypes of the control and type 2 diabetic groups; all activities were found significantly lower in diabetics. In conclusion, we suggested that paraoxonase activities are affected by PON1 genetic variability in patients with type 2 diabetes mellitus and controls.
From epidemiological studies, there is some evidence that genetic variation at the glutathione S-... more From epidemiological studies, there is some evidence that genetic variation at the glutathione S-transferase (GST) loci GSTM1 influences individual susceptibility to disease associated with oxidative stress. The aim of this study was to elucidate the role of the GSTM1 genotype in protection against oxidant chemicals by comparing the sensitivity, genotoxicity and cytotoxicity of lymphocytes to benzo(a)pyrene (BaP)-and cumene hydroperoxide (CumOOH)-induced in vitro oxidative challenge. Malondialdehyde and protein carbonyl levels, and oxidation of 2%,7%-dichlorofluorescin diacetate were used as biomarkers of oxidative stress in lymphocytes. Following supplementation with BaP or CumOOH, time-dependent increases were observed in the production of all the markers after incubation for 12-48 h. However, we could not find any differences between GSTM1 null and positive genotypes. Furthermore, dose or time response experiments indicated that GSTM1-deficient cells were not more sensitive than control cells to BaP-or CumOOH-induced cell killing and micronucleus formation, although they were hypersensitive to BaP-inhibited cellular growth. The results suggest that lymphocytes from individuals with the GSTM1 null genotype are not abnormally susceptible to in vitro induced oxidant challenge, when exposed to CumOOH.
The serine/threonine kinase liver kinase B 1 (LKB1) is a multifunctional protein and has been ass... more The serine/threonine kinase liver kinase B 1 (LKB1) is a multifunctional protein and has been associated with various cancer types. Although the tumor suppressor function of LKB1 is attributed mainly to its ability to phosphorylate directly different adenosine monophosphate-activated protein kinases, its regulation is still poorly understood. More recently, it has been shown that LKB1 expression can be regulated by forkhead box O transcription factors via cis-acting elements, which are found in the promoter region of the LKB1 gene. In this study, we investigated LKB1 messenger RNA expression levels in association with the promoter methylation of the gene and forkhead box O member 3 (FOXO3) messenger RNA expression in head and neck squamous cell carcinoma (HNSCC) tumor samples. Our results show that LKB1 expression is downregulated, especially in advanced-stage tumor samples, and this downregulation was not the result of promoter methylation or modulation by FOXO3 (P = 0.656). Despite observing a positive association between the LKB1 and FOXO3 expression levels in the tumors, this association was not statistically significant (P = 0.24). Our results indicate that downregulation of LKB1 is independent of FOXO3 and may be implicated in the progression of HNSCC.
Aim: We investigated the vascular effects of agmatine (decarboxylated arginine = AGM), an endogen... more Aim: We investigated the vascular effects of agmatine (decarboxylated arginine = AGM), an endogenous ligand for ␣ 2-adrenoceptors and imidazoline receptors, present in endothelium and smooth muscle, using the diabetic rat aortae. Materials and methods: Studies were performed in control group (0.2 ml i.p. saline, n = 10), streptozotocin (STZ)-diabetic control group (60 mg kg −1 STZ i.p., n = 10), agmatine (AGM)-control group (5 mg kg −1 day −1 i.p. AGM for 1 month, n = 10), citrate-control group (0.2 ml 0.01 M, n = 10), insulin-treated diabetic group ((3 U kg −1 NPH + 1 U kg −1 regular insulin) twice per day, for 1 month, n = 10) and AGM-treated diabetic group (5 mg kg −1 day −1 i.p. for 1 month, n = 10). All values are expressed as means ± S.E.M. Statistical analysis of the data was performed using ANOVA followed by Tukey multiple comparisons test. Results: One-month AGM-treatment significantly decreased the blood glucose levels of diabetic rats (502 ± 44 mg dl −1 to 343 ± 31 mg dl −1 , P < 0.001). Fast, slow and total components of responses to noradrenaline in all the experimental groups were not significantly affected by AGM-treatment. AGM reversed the decreased responses of acetylcholine (pD 2 and Inh.%, P < 0.001 and P < 0.05) in diabetic rats although it did not affect the responses of sodium nitroprusside in all groups. The contraction values of KCl in all groups were not affected by AGM-treatment. Conclusion: AGM-treatment could improve the increased blood glucose level, reverse the endothelial dysfunction and normalize the endothelium-dependent relaxation responses in STZ-diabetic rats.
The aim of the present study was to investigate the effect of donor aging on the glutathione conj... more The aim of the present study was to investigate the effect of donor aging on the glutathione conjugate transport in erythrocytes and whether it plays a role in the resistance to oxidative stress of the erythrocytes of aging subjects. In our comparative study on intact erythrocytes of healthy aging and young adults, in which 2,4-dinitrophenyl-S-glutathione (DNP-SG) was used as model glutathione S-conjugate, we found that the efflux of DNP-SG remained unchanged in the aged subjects. This result suggests that the detoxification function is maintained against the chemical stress employed in erythrocytes of aging subjects. In the assay conditions used, which were optimized to obtain maximal inhibition of glutathione S-conjugate transport, our results also indicated that the susceptibility of erythrocytes to in vitro lipid peroxidation generated by cumene hydroperoxide was enhanced by pretreatment with DNP-SG inhibitors in both age groups. However, the difference in susceptibility was not a function of aging. Further, the results suggested that inhibition of glutathione S-conjugate pump may impair cellular protection of the erythrocytes against oxidative damage.
Objective: It is known that point mutations, duplications and deletions occur in mitochondrial DN... more Objective: It is known that point mutations, duplications and deletions occur in mitochondrial DNAs (mtDNA) of different tissues of individuals. Among the deletions observed, mt4977 mutation, which is located at nucleotide positions 8470-8482 and 13447-13459 and causes the loss of 4977 base pairs, is the most common. mtDNA 4977 deletion leads to the loss of 8 genes encoding subunits of respiratory chain complexes. Consequently, the deletion could be expected to inhibit the oxidative function and reduce ATP production level. It is known that mitochondrial ATP production has an important role on platelet functions. However, there is no information about this in the literature. Since platelet activation in ischemic heart disease (IHD) has been shown to play an important role in the pathophysiology of the disease, we wanted to examine the relationship between platelet function and mtDNA 4977 deletion in ischemic heart disease. Material and Method: Platelet functions were studied by giving ADP stimulus with the help of lumiaggregometer device to evaluate in terms of secretion and aggregation. ATP measurement was performed with the bioluminescence assay kit. mtDNA 4977 deletion was determined by the modified simultaneous quantitative polymerase chain reaction method. Results: The frequency of mtDNA 4977 deletion and mtDNA copy number were higher in platelets of the patients compared with the healthy control group (p<0.05). However, no significant differences in platelet ATP content, and in their slope (Ω) and % amplitude values were observed between both groups (p>0.05). Conclusion: It was observed that increased deletion in patients with IHD did not have a significant effect on platelet dysfunction compared with healthy control subjects. ÖZET Amaç: Bireylerin farklı dokularındaki mitokondriyal DNA'larında (mtDNA) nokta mutasyonları, duplikasyonlar ve delesyonlar meydana geldiği bilinmektedir. Gözlenen delesyonlar içerisinde 8470-8482 ile 13447-13459 nükleotid pozisyonlarında yer alan ve 4977 baz çiftinin kaybına yol açan mtDNA 4977 mutasyonu en sık olarak görülmtedir. mtDNA 4977 delesyonu solunum zinciri komplekslerinin alt ünitlerini kodlayan 8 genin kaybolmasına yol açar. Buna bağlı olarak delesyonun oksidatif fonksiyonu engellemesi ve ATP üretim düzeyini azaltması beklenebilir. Mitokondriyal ATP üretiminin trombosit fonksiyonları üzerinde önemli bir rolü olduğu bilinmektedir. Ancak bununla ilişkili olarak literatürde herhangi bir bilgi göze çarpmamaktadır. İskemik kalp hastalığında (İKH) trombosit aktivasyonunun hastalık fizyopatolojisinde önemli bir rol oynadığı gösterildiğinden, bu çalışmamızda trombosit fonksiyonu ile mtDNA 4977 delesyonu arasındaki ilişkiyi ve iskemik kalp hastalığı gelişimindeki olası etkilerini araştırmayı amaçladık. Gereç ve Yöntem: Trombosit fonksiyonları, sekresyon ve agregasyon açısından değerlendirilmek üzere lumiagregometre cihazı yardımı ile ADP uyaranı verilerek çalışıldı. ATP ölçümü biyolüminesans test kiti ile yapıldı. mt4977 delesyonu, modifiye edilmiş eşzamanlı kantitatif polimeraz zincir reaksiyonu (RT-PCR) yöntemi ile belirlendi. Bulgular: Hastaların trombositlerinde mtDNA 4977 delesyon sıklığı ve mtDNA kopya sayısı sağlıklı kontrol grubuna göre daha yüksekti (p <0.05). Ancak her iki grup arasında trombosit ATP içeriği ile bunların eğim (Ω) ve % amplitüd değerlerinde anlamlı farklılık gözlenmedi (p> 0.05). Sonuç: Sağlıklı kontrol denekleriyle karşılaştırıldığında, İKH hastalarında artmış delesyonun trombosit disfonksiyonu üzerinde anlamlı bir etkiye sahip olmadığı görülmüştür.
It is known that erythrocyte aggregation in renal tissue during preserva- tion is cause of microc... more It is known that erythrocyte aggregation in renal tissue during preserva- tion is cause of microcirculation defects in the reperfusion period. The aim of our study is to investigate oxidative damage in erythrocytes relative to the time of cold ischemia during organ preservation and relationship between lipid peroxidation and development of these damages. In experiments with a rabbit model, explant- ed kidneys were exposed to perfusion and 96 hours preservation with Euro-Collins (EC) in the 1st group, and University of Wisconsin (UW) solution in the 2nd group. Electron- microscopic examinations in renal tissues were performed. Lipid peroxidation and glu- tathione levels in erythrocytes preserved in the same solutions were investigated. Agglutination of the erythrocytes and adhe- sion to the endothelium with ‡24 hours preservation were observed in the kidney tis- sue of the first group, and after ‡48 hours preservation in the second group. During preservation of the erythrocytes in or...
Object. Thyroid cancer (TC) is a rare type of cancer which occurs as a result of environmental an... more Object. Thyroid cancer (TC) is a rare type of cancer which occurs as a result of environmental and genetic factors. Although different types of genetic and epigenetic changes are associated with TC, the molecular mechanism still remains unclear. SRY-box transcription factor 15 (SOX15) is an important transcription factor, and its expression is altered in many cancer types by epigenetic modifications. Recently, miR-147b overexpression has been associated with SOX15 silencing in TC. Methods. In this study, qRT-PCR was used to investigate the expression levels of the SOX15 gene and of miR-182, miR-183, miR-375, and miR-96 in thyroid tumors and adjacent noncancerous tissues. We also investigated the methylation status of the SOX15 promoter by methylation-specific PCR in tumors and adjacent noncancerous tissues. Results. We observed a statistically significant downregulation of SOX15 expression in tumors compared to noncancerous tissue samples. The methylation levels of tumors and matche...
The extract from larval Lucilia sericata is used clinically to promote wound healing and tissue r... more The extract from larval Lucilia sericata is used clinically to promote wound healing and tissue regeneration. However, its effect and underlying mechanisms on fibroblast cells, which are involved in the wound healing process, are still poorly understood. This study aimed to examine the effects of larval secretions on dermal fibroblast activity and gene expression and to evaluate the wound healing potential of their major components. Primary rat fibroblasts were cultured and treated with larval secretions. Following the treatment, the cells were used to extract RNA for gene profiling. In addition, migration to the injury site was studied with the scratch healing assay. Our results showed that larval secretion accelerated the migration of the fibroblasts compared to the control cells and that several mRNAs were differentially expressed during a period of 72 h incubation. Additionally, we analyzed the chemical composition of larval secretions and showed that fumaric acid, ferulic acid, and p-coumaric acid, which were selected and identified for their major components, enhanced the migration of the fibroblasts. Therefore, these results indicate that L. sericata larval secretions could modulate the mRNA expression of some wound healing-related genes of the fibroblasts and contain the effective components for wound healing.
Normal wound healing is achieved by a cascade of many cellular activities. This process is affect... more Normal wound healing is achieved by a cascade of many cellular activities. This process is affected by some of the metabolic diseases like Diabetes Mellitus (DM). DM causes bad prognosis and is one of the major contributors to chronic wound healing problems. Recently, Lucilia sericata larvae are used for wound healing as they are very effective agents in wound healing process. It's still unclear that how the larvae affect the molecular mechanisms and signaling pathways of chronic wound healing. MicroRNAs (miRNAs) can induce gene expression in post-transcriptional mechanisms. In this study, our aim was to determine whether the larvae secretions could change the expression patterns of selected miRNAs on the diabetic microenvironment. Methods: Wistar Albino rats were classified as diabetic and nondiabetic, then full thickness cutaneous wounds were created at the dorsal region of rats. Wound tissues were collected on days 0, 3, 7 and 14 post wounding. The association between miR21, miR146a, miR146b and miR29a gene expression profiles and wound healing Amaç: Normal yara iyileşmesi bir çok hücresel faaliyetin zincirleme tepkimeleri ile gerçekleşmektedir. Diabetes Mellitus gibi metabolik hastalığa sahip kişilerde ise bu süreç olumsuz etkilenmekte, kötü iyileşen ya da iyileşmeyen kronik yaraların meydana gelmesine neden olmaktadır. Lucilia sericata larvalarının yara iyileşmesinde etkin rol oynamakta olduğu bildirilmiştir ancak kronik yara iyileşmesinin moleküler mekanizmasında ve ilgili yolaklardaki etkileri hala bilinmemektedir. RNA türlerinden biri olan mikroRNA'ların (miRNA) bir bölümünün yüksek glukoz düzeylerinde ekspresyonlarının değiştiği gösterilmiştir. Bu sebeple çalışmamızda; yara iyileştirmesinde rolü olduğu bildirilen bazı miRNA'ların ekspresyonlarının diyabetik şartlarda larva salgısı uygulaması ile deri iyileşmesi süresince ne yönde etkilendiği incelenmiştir. Yöntemler: Deneysel çalışmamızda kullanılan Wistar Albino türü sıçanlar diyabetik ve diyabetik olmayanlar olarak gruplandırıldıktan sonra sırt bölgesinde tam kat yara oluşturulmuştur. Oluşturulan yara bölgelerinden 0., 3., 7. ve 14. günlerde biyopsi örneği alınmıştır. Çalışmamızda literatür taraması yapılarak yara iyileşmesi ile ilişkilendirilmiş miR21, miR146a, miR146b ve miR29a genlerinin
Some anesthetics including ketamine/xylazine and thiopental have been shown to alter the expressi... more Some anesthetics including ketamine/xylazine and thiopental have been shown to alter the expression of genes related with inflammatory cytokines and chemokines in previous studies unassociated with wound healing, arising the question of whether commonly used anesthetics in wound healing models could interfere with the transcriptional responses of the genes associated with skin wound healing. The gene expression profile in wound biopsies of rats who received widely used anesthetics doses of intraperitoneal ketamine/xylazine (50 mg/kg and 10 mg/kg) or thiopental (50 mg/kg) in comparison with control rats was analyzed by monitoring the expression of genes effective on various phases of wound healing. The expression levels of 84 genes were determined on 3rd, 7th and 14th days of post-wounding using a qPCR array system. Of the genes either up or downregulated fivefolds or more, three (Egf, Col5a1 and Cxcl3) and two (Tgfa and Il2) genes were found to be the most responsive ones to ketamine/xylazine or thiopental anesthesia respectively in a period of 14 days after correction for multiple testing. However, up to 22 and 24 genes for ketamine/xylazine and thiopental were found to be differentially expressed in the same period without correction for multiple-comparisons testing (p < 0.05). In conclusion, our data suggest that ketamine/xylazine and thiopental may alter the transcriptional responses of some genes associated with wound healing in rats. We strongly suggest to consider the possible alteration effect of these anesthetics on gene expression in animal models of dermal wound healing.
Turkish journal of haematology : official journal of Turkish Society of Haematology, Jan 5, 2002
To evaluate the role the coagulation and fibrinolysis abnormalities in the pathogenesis of ischem... more To evaluate the role the coagulation and fibrinolysis abnormalities in the pathogenesis of ischemic stroke of undetermined etiology, we assayed plasma concentration of fibrinopeptide-A and thrombin-antithrombin III complex, both sensitive markers for thrombin activation and fibrin formation, and D-dimer, a marker of plasmin activity and fibrinolysis. Hemostatic markers were measured in 32 patients with acute stroke and 20 patients with chronic stroke, and compared with 21 normal subjects. Fibrinopeptid-A and thrombin-antithrombin III complex levels were not elevated significantly, whereas the D-dimer level was markedly raised in acute (p< 0.001) and chronic (p< 0.05) phases of ischemic stroke in comparison with the control group. Prolonged elevation of D-dimer concentration suggests that hemostatic abnormalities have a primary role in the pathogenesis of ischemic stroke. The measurement of D-dimer concentration may help to better decide the indications for therapy of the patie...
To compare glutathione S-conjugate transport in obese and nonobese persons, and how glutathione S... more To compare glutathione S-conjugate transport in obese and nonobese persons, and how glutathione S-conjugates are involved in the antioxidant status in obesity. The efflux of glutathione conjugates and malondialdehyde (MDA) levels were measured in erythrocytes of obese (N = 33) and nonobese (N = 28) persons at every 30 min during a 120 min incubation time in vitro. 2,4-dinitrophenyl-S-glutathione (DNP-SG) represented the glutathione S-conjugate. The efflux of conjugate in erythrocytes from obese subjects (708 +/- 147 DNP-SG efflux nmol/ml erythrocytes/h) was significantly higher than that of control group (490 +/- 105 DNP-SG efflux nmol/ml erythrocytes/h) (P &lt; 0.05). At all time points measured (30-120 min), there was an increase in DNP-SG efflux in obese group (P &lt; 0.05). This is manifested by a decrease in cellular DNP-SG levels. The susceptibility of erythrocytes to in vitro 1-chloro-2,4-dinitrobenzene (CDNB)-induced oxidative stress were greater for cells of control group (P &lt; 0.05), although hemolysis sensitivity of these cells are not different between both groups (P &gt; 0.05). Following CDNB pretreatment, incubation of erythrocyte with vanadate, a DNP-SG transport inhibitor, resulted in an increase of MDA in both groups. However, in this case, the difference in susceptibility was not related to obesity. On the other hand, while erythrocyte glutathione level was lower in obese subjects (79% of control) than in controls (P &lt; 0.05), the adenosine 5&#39;-triphosphate (ATP) levels, the enzyme activities of glutathione S-transferase (GST) and the conjugation capacities of the erythrocytes were not different between groups (P&gt;0.05). Obesity may increase erythrocyte glutathione conjugate transport independent from ATP and GST activity that may protect against MDA formation in vitro.
Journal of Basic and Clinical Physiology and Pharmacology, 2006
The development of diabetic complications has usually been attributed to the nonenzymic glycation... more The development of diabetic complications has usually been attributed to the nonenzymic glycation of tissue proteins. Only recently, however, have researchers examined the possible role on free radicals in the pathogenesis of diabetes. In the present study, glutathione (GSH) and major antioxidant enzyme levels in plasma of patients with type II diabetes mellitus were assessed both before and after 3 months of N-acetylcysteine (NAC) therapy. Thirty-two diabetic patients were examined as well as fifteen healthy controls. Before treatment with NAC, glutathione peroxidase (GPx), catalase (CAT), and (GSH) levels of diabetic patients and control subjects showed no significant differences, whereas glutathione S-transferase (GST) levels were higher in type II diabetic patients. Following 3 months of Following NAC supplementation, GSH, GST, and CAT levels were found to be similar to the levels before treatment. On the other hand, GPx activity was significantly lower compared with the values before treatment. According to this finding, NAC treatment could have a positive effect on GPx values in type II diabetic patients showing abnormally high values.
The anti-epileptic drug vigabatrin was developed as an inhibitor of gamma-aminobutyric acid trans... more The anti-epileptic drug vigabatrin was developed as an inhibitor of gamma-aminobutyric acid transaminase, and its ability to increase inhibition in the central nervous system led to its testing in an animal model. In animal models chronic use of vigabatrin is associated with irreversible myelin vacuolation. Antioxidant drugs change the antioxidant capacity of the body. Oxidative stress of the body increased when valproic acid and carbamazepine were used chronically. To assess whether vigabatrin may affect protein oxidation and lipid peroxidation, glutathione, glutathione peroxidase (GPx), and glutathione-S-transferase (GST) levels were studied in the livers of 57 rat fetuses after administration of vigabatrin to the mothers (19 in the first week of pregnancy, 20 in the second week, and 18 in the third week) and in 19 control rat fetuses without vigabatrin. We compared the results of administration of vigabatrin in each group with the controls. Rat fetus protein oxidation in group I (0.686 nmol/mg protein) and group II (0.723 nmol/mg protein) was higher than in the control group (0.388 nmol/mg protein). Lipid peroxidation (0.209, 0.224, 0.253 nmol/mg protein, respectively) and GPx levels (345.4, 329.0, 283.2 nmol/mg protein, respectively) of groups I, II, and III were higher than in the control group (0.104, 167.2 nmol/mg protein, respectively). GST in group II (79.2 nmol/mg protein) and group III (77.8 nmol/mg protein) were not different from that in the control group (78 nmol/mg protein). It was found that vigabatrin affected all the parameters that were studied, especially in group I, which was given the drug in the first week of pregnancy.
Recent epidemiological studies proposed that the glutathione S-transferase (GST) M1-null genotype... more Recent epidemiological studies proposed that the glutathione S-transferase (GST) M1-null genotype may contribute to diseases associated with oxidative stress. The genetic polymorphism exhibited by the GSTM1 may be an important factor in risk toward oxidant chemicals. In this study, we investigated the e¡ect of GSTM1-null genotype in lymphocyte and oxidative stress-dependent inhibition of platelet aggregation. To determine whether GSTM1 de¢ciency is a genetic determinant of cell toxicity toward oxidant chemicals, lymphocytes were incubated in vitro with low levels of benzo(a)pyrene (BaP), cumene hydroperoxide (CumOOH), or trans-stilbene oxide that do not decrease cell viability, and were assessed for oxidative damage and for the lymphocyte-dependent inhibition of platelet response. Malondialdehyde and carbonyl levels, and the oxidation of cisparinaric acid, were used as biomarkers of oxidative stress in lymphocytes. Following stimulation by BaP or CumOOH, when peroxidation-dependent changes in these parameters were compared between the GSTM1-null genotype and the positive genotype, no signi¢cant di¡erences were found between the two genotypes. On the other hand, preincubation of the lymphocytes with BaP or CumOOH attenuated their inhibitory action on ADP-induced platelet aggregation. However, our results indicate that lymphocytes of individuals with the GSTM1-null genotype have greater inhibitory activity on platelet function after exposure to BaP, but not CumOOH, although they are not more susceptible to in vitro oxidative stress.
Objective: Paraoxonase-1 (PON1) is an HDL-associated enzyme implicated in the pathogenesis of ath... more Objective: Paraoxonase-1 (PON1) is an HDL-associated enzyme implicated in the pathogenesis of atherosclerosis by protecting lipoproteins against peroxidation. PON1 has two genetic polymorphisms both due to amino acid substitution, one involving glutamine and arginine at position 192 and the other leucineand methionine at position 55. Our study aimed to compare the effect of PON192 polymorphism and PON1 activity in patients with type 2 diabetes mellitus (T2DM) and non-diabetic controls. Material and Methods: 50 patients with T2DM and 30 non-diabetic controls were included in this study. The PON192 polymorphism was studied by polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP). Paraoxonase activity was measured by spectrophotometric method. Results: The frequencies of the QQ, QR and RR genotypes were found as 36.5 and 14% in type 2 diabetes patients and 26.67, 46.66, 26.67% in control subjects, respectively. The paraoxonase activity was detected at lower levels in diabetics (102.0 ±38.9) than in control subjects (158.1±63.7). PON1192 RR homozygotes had significantly higher PON activity than QR and QQ genotypes among control and type 2 diabetes patients (p<0.005). Conclusion: In comparing the activities of three genotypes of the control and type 2 diabetic groups; all activities were found significantly lower in diabetics. In conclusion, we suggested that paraoxonase activities are affected by PON1 genetic variability in patients with type 2 diabetes mellitus and controls.
From epidemiological studies, there is some evidence that genetic variation at the glutathione S-... more From epidemiological studies, there is some evidence that genetic variation at the glutathione S-transferase (GST) loci GSTM1 influences individual susceptibility to disease associated with oxidative stress. The aim of this study was to elucidate the role of the GSTM1 genotype in protection against oxidant chemicals by comparing the sensitivity, genotoxicity and cytotoxicity of lymphocytes to benzo(a)pyrene (BaP)-and cumene hydroperoxide (CumOOH)-induced in vitro oxidative challenge. Malondialdehyde and protein carbonyl levels, and oxidation of 2%,7%-dichlorofluorescin diacetate were used as biomarkers of oxidative stress in lymphocytes. Following supplementation with BaP or CumOOH, time-dependent increases were observed in the production of all the markers after incubation for 12-48 h. However, we could not find any differences between GSTM1 null and positive genotypes. Furthermore, dose or time response experiments indicated that GSTM1-deficient cells were not more sensitive than control cells to BaP-or CumOOH-induced cell killing and micronucleus formation, although they were hypersensitive to BaP-inhibited cellular growth. The results suggest that lymphocytes from individuals with the GSTM1 null genotype are not abnormally susceptible to in vitro induced oxidant challenge, when exposed to CumOOH.
The serine/threonine kinase liver kinase B 1 (LKB1) is a multifunctional protein and has been ass... more The serine/threonine kinase liver kinase B 1 (LKB1) is a multifunctional protein and has been associated with various cancer types. Although the tumor suppressor function of LKB1 is attributed mainly to its ability to phosphorylate directly different adenosine monophosphate-activated protein kinases, its regulation is still poorly understood. More recently, it has been shown that LKB1 expression can be regulated by forkhead box O transcription factors via cis-acting elements, which are found in the promoter region of the LKB1 gene. In this study, we investigated LKB1 messenger RNA expression levels in association with the promoter methylation of the gene and forkhead box O member 3 (FOXO3) messenger RNA expression in head and neck squamous cell carcinoma (HNSCC) tumor samples. Our results show that LKB1 expression is downregulated, especially in advanced-stage tumor samples, and this downregulation was not the result of promoter methylation or modulation by FOXO3 (P = 0.656). Despite observing a positive association between the LKB1 and FOXO3 expression levels in the tumors, this association was not statistically significant (P = 0.24). Our results indicate that downregulation of LKB1 is independent of FOXO3 and may be implicated in the progression of HNSCC.
Aim: We investigated the vascular effects of agmatine (decarboxylated arginine = AGM), an endogen... more Aim: We investigated the vascular effects of agmatine (decarboxylated arginine = AGM), an endogenous ligand for ␣ 2-adrenoceptors and imidazoline receptors, present in endothelium and smooth muscle, using the diabetic rat aortae. Materials and methods: Studies were performed in control group (0.2 ml i.p. saline, n = 10), streptozotocin (STZ)-diabetic control group (60 mg kg −1 STZ i.p., n = 10), agmatine (AGM)-control group (5 mg kg −1 day −1 i.p. AGM for 1 month, n = 10), citrate-control group (0.2 ml 0.01 M, n = 10), insulin-treated diabetic group ((3 U kg −1 NPH + 1 U kg −1 regular insulin) twice per day, for 1 month, n = 10) and AGM-treated diabetic group (5 mg kg −1 day −1 i.p. for 1 month, n = 10). All values are expressed as means ± S.E.M. Statistical analysis of the data was performed using ANOVA followed by Tukey multiple comparisons test. Results: One-month AGM-treatment significantly decreased the blood glucose levels of diabetic rats (502 ± 44 mg dl −1 to 343 ± 31 mg dl −1 , P < 0.001). Fast, slow and total components of responses to noradrenaline in all the experimental groups were not significantly affected by AGM-treatment. AGM reversed the decreased responses of acetylcholine (pD 2 and Inh.%, P < 0.001 and P < 0.05) in diabetic rats although it did not affect the responses of sodium nitroprusside in all groups. The contraction values of KCl in all groups were not affected by AGM-treatment. Conclusion: AGM-treatment could improve the increased blood glucose level, reverse the endothelial dysfunction and normalize the endothelium-dependent relaxation responses in STZ-diabetic rats.
The aim of the present study was to investigate the effect of donor aging on the glutathione conj... more The aim of the present study was to investigate the effect of donor aging on the glutathione conjugate transport in erythrocytes and whether it plays a role in the resistance to oxidative stress of the erythrocytes of aging subjects. In our comparative study on intact erythrocytes of healthy aging and young adults, in which 2,4-dinitrophenyl-S-glutathione (DNP-SG) was used as model glutathione S-conjugate, we found that the efflux of DNP-SG remained unchanged in the aged subjects. This result suggests that the detoxification function is maintained against the chemical stress employed in erythrocytes of aging subjects. In the assay conditions used, which were optimized to obtain maximal inhibition of glutathione S-conjugate transport, our results also indicated that the susceptibility of erythrocytes to in vitro lipid peroxidation generated by cumene hydroperoxide was enhanced by pretreatment with DNP-SG inhibitors in both age groups. However, the difference in susceptibility was not a function of aging. Further, the results suggested that inhibition of glutathione S-conjugate pump may impair cellular protection of the erythrocytes against oxidative damage.
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Papers by AHMET OZAYDIN