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    Dynamic thiol / disulfide homeostasis in metabolically healthy obese adolescents
    (2020) Yuce, Ozge; Erel, Ozcan
    Aim: This study aim to discuss the possible role of oxidant-antioxidant balance in providing metabolic health in obese adolescents by determining the oxidant-antioxidant status. Material and Methods: 98 metabolically healthy obese and 75 normal-weight adolescents participated in the study. Obese individuals were grouped according to the severity of obesity. Biochemical parameters including thiol/ disulfide homeostasis were analyzed. Serum native thiol (SH), total thiol (SH+SS) and disulfide (SS) concentrations were determined using a novel automated measurement method. Disulfide to native thiol ratio (SS/SH), disulfide to total thiol ratio(SS/(SH+SS)), and native thiol to total thiol ratio (SH/(SH + SS)) were calculated and were presented as percentage. Results: Native and total thiol levels-as an antioxidative parameter-was significantly higher in obese adolescents compared to healthy-weight adolescents (p0.001). Native thiol/total thiol ratio was slightly higher in the obese group, but not statistically significant (p=0.4). Disulfide levels, disulfide/native thiol and disulfide/total thiol ratios were not different between the groups. We found that the levels of the antioxidant parameters, native thiol, and total thiol increased significantly along with the severity of the obesity, while other parameters remained comparable. We also found a significant increase in antioxidant parameters correlated with the severity of obesity (p0.001). Conclusion: This study concluded that the increased antioxidant status and activity in obese adolescents may be related to the metabolic health.
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    Prolonged jaundice in newborns is associated with low antioxidant capacity in breast milk
    (Taylor & Francis Ltd, 2010) Uras, Nurdan; Tonbul, Alpaslan; Karadag, Ahmet; Dogan, Derya G.; Erel, Ozcan; Tatli, Mustafa M.
    In breastfeeding newborns who are otherwise healthy, the mechanism of prolonged jaundice remains unclear. The aim of this study was to investigate relations between prolonged jaundice and oxidative parameters in breast milk. Full-term, otherwise healthy newborns with jaundice lasting more than 2 weeks were enrolled prospectively in the study. As a control group, newborns in the same age group but without prolonged jaundice were selected. All newborns in the study were exclusively breastfed. In the newborns with prolonged jaundice, investigations of the etiology of the jaundice included complete blood count, peripheral blood smear, blood typing, direct Coombs test, measurement of serum levels of total and direct bilirubin, tests for liver and thyroid function (TSH, free T4, total T4), urine culture and measurement of urine reducing substances, and determination of glucose 6 phosphate dehydrogenase enzyme levels. Breast milk was collected from the mothers of the newborns in both groups. The antioxidant status of the breast milk was assessed via determination of total antioxidant capacity (TAG). Oxidative stress was also assessed in breast milk by measurement of total oxidation status (TOS) and calculation of the oxidative stress index (OSI). The prolonged jaundice group differed significantly from the control group in terms of mean TAG and OSI (p < 0.001), but not in terms of TOS. In conclusion, in the breast milk of mothers of newborns with prolonged jaundice, oxidative stress was found to be increased, and protective antioxidant capacity was found to be decreased.
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    The Relationship Between Vitamin-D Deficiency and Protein Oxidation Among Obese Children
    (Taylor & Francis Inc, 2023) Surucu Kara, Ilknur; Mertoglu, Cuma; Siranli, Guelsah; Arslan, Yusuf Kemal; Gok, Gamze; Erel, Ozcan
    Aim: The aim of the study is to examine the relationship between obesity, Vitamin-D deficiency, and protein oxidation. Methods: Thiol-disulfide homeostasis, Vitamin-D, ischemia modified albumin, insulin, and lipid levels were compared among obese, pre-obese and normal-weight healthy children. Results: A total of 136 children (69 boys and 67 girls) were included in the study. The vitamin-D levels of obese children were lower than those of pre-obese and normal weight (p < 0.05). In the normal weight group, total thiol and native thiol were lower in the pubertal period than in adolescence; were higher in those with sufficient Vitamin-D level than those with insufficient and deficient Vitamin-D (p < 0.05). Vitamin-D level was lower in pre-obese girls than boys (p < 0.05). Those with high triglycerides had high disulfide/total thiol, disulfide, and disulfide/native thiol and low native thiol/total thiol (p < 0.05). Conclusion: Thiol-disulfide homeostasis is negatively affected by low vitamin D levels, pubertal period and high triglyceride levels.
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    The role of thiol/disulfide homeostasis in the differentiation of transudative and exudative pleural effusion
    (2022) Abuzaina, Osama; Hezer, Habibe; Karalezli, Aysegul; Abuzaina, Seray; Neselioglu, Salim; Erel, Ozcan; Hasanoglu, H. Canan
    Aim: The dynamic thiol/disulfide homeostasis performs a major role in keeping up the oxidant-antioxidant equilibrium. We aimed to find the role of dynamic thiol/disulfide balance in pleural effusion transudate-exudate differentiation. This is considered to be the first research investigating the thiol/disulfide homeostasis in pleural fluid. Materials and Methods: This prospective study was conducted in the Clinic of Chest Diseases of Training and Research Hospital. One hundred adult patients with pleural effusion included. 20-100 cc pleural fluid samples were taken through thoracentesis of the patients. These fluids were categorized as exudate and transudate according to Light’s criteria. Automatic spectrophotometric practice which was defined by Erel & Neselioglu was used to gauge thiol/disulfide homeostasis in pleural fluid. Results: Disulfide, total and native thiol levels were significantly higher in the exudative group than the transudative group (p = 0.001). The ratio of disulfide/native thiol and disulfide/total thiol was higher in the transudative group (p = 0.03). In exudates, native thiol/total thiol proportions were higher (p = 0.03). Conclusion: The increased disulfide levels are indicative of increased oxidative stress in exudative pleural fluid. An abnormal thiol/disulfide state may be a major factor in the pathogenesis. These outcomes may conduce to distinguish exudative fluids without requesting synchronous serum thiol/disulfide level measurement.
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    Serum ischemia modified albumin and dynamic thiol/disulfide homeostasis in early- and late-onset preeclampsia
    (2020) Adanas Aydin, Gultekin; Ozgen, Gulten; Neselioglu, Salim; Erel, Ozcan
    Aim: In the present study, we aimed to evaluate serum IMA, IMA/albumin ratio, and DTDH levels in patients with early- and late-onset PE compared to healthy controls.Impaired homeostasis between oxidant and antioxidant mechanisms, inflammatory processes, and endothelial dysfunction play a key role in the pathogenesis of preeclampsia (PE). Serum ischemia modified albumin (IMA) and dynamic thiol/disulfide homeostasis (DTDH) levels are elevated in the presence of inflammation, oxidative stress, and endothelial dysfunction. Material and Methods: A total of 24 patients with early-onset PE and 62 patients with late-onset PE were included.The control group consisted of 46 healthy controls with similar gestational weeks. Serum samples were collected and IMA, albumin, and native, total, and disulfide thiol levels analyzed. Corrected IMA/albumin ratios were also calculated.Results: Disulfide levels, disulfide/native and disulfide/total thiol levels were higher in patients with early-onset PE compared to late-onset patients(p=0.008, p=0.022, and p=0.021, respectively). However, there was no significant difference between the late-onset PE patients and late-onset PE controls. Although there was no significant difference in the IMA levels between the patient and control groups, the IMA/albumin ratio was higher in the early-onset and late-onset PE patients, compared to the control group. However, there was no significant difference between the early-onset and late-onset PE patients.Conclusion: Our study results showed increased disulfide levels, disulfide/native thiol, disulfide/total thiol and IMA/albumin ratio in the early-onset PE patients, indicating increased oxidative stress in the pathogenesis of PE. In the late-onset PE patients, there was an increase only in the IMA/albumin ratio. However, further large-scale, prospective studies are needed to confirm the diagnostic value of these markers in the clinical practice.
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    Thiol/Disulfide Homeostasis in Patients with Central Serous Chorioretinopathy
    (Taylor & Francis Inc, 2016) Turkoglu, Elif Betul; Dikci, Seyhan; Celik, Erkan; Erel, Ozcan; Neselioglu, Salim; Alisik, Murat; Koca, Cemile
    Purpose: To evaluate dynamic thiol/disulfide homeostasis in patients with chronic central serous chorioretinopathy (cCSC).Methods: This prospective study included 34 cCSC cases and 37 healthy individuals who were age- and sex-matched. A new colorimetric method for measuring thiol/disulfide homeostasis was used. Native thiol, total thiol/disulfide levels, disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol ratios were measured.Results: The age and gender distributions were similar in both main groups. The mean duration of disease was 47.29 24 months. Native and total thiol levels were significantly lower among the cCSC group relative to the control group (p < 0.001). There was not a statistically significant difference between the cCSC and the control group in terms of disulfide levels (p = 0.492). While disulfide/native thiol and disulfide/total thiol ratios were elevated, the native thiol/total thiol ratio was decreased in the cCSC group (p = 0.017, 0.021, 0.036, respectively). Ratios obtained using plasma native thiol, total thiol, and disulfide levels differed significantly between the both groups.Conclusion: Disulfide/thiol ratio was significantly greater in cCSC patients relative to healthy control subjects. Our results suggest that the oxidative process is involved in the pathogenesis of the cCSC.