Publications by authors named "Guler Ozturk"

Article Synopsis
  • The review highlights the connection between melatonin and aging, emphasizing the decline of melatonin levels as a significant factor in age-related diseases.
  • Melatonin influences various biological functions, including circadian rhythms and immune response, and its decline is linked to oxidative stress and mitochondrial dysfunction, which are key components of the aging process.
  • The text suggests that melatonin supplementation could be beneficial for older adults, particularly in relation to COVID-19 treatment, given the increased fatality rates among this population and the need for further research on this topic.
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Objectives: The aim of the study was to investigate the possible effects of radiofrequency radiation (RFR) at different frequencies for different exposure durations on caspase-dependent apoptosis pathways in human colon adenocarcinoma (HT-29).

Methods: HT-29 cells were exposed to 1800 MHz; 2100 MHz and 2600 MHz RFR for 3 h cont., 6 h int.

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Background: Vitamin D regulates calcium and phosphorus metabolism, and it is essential for bone formation. Several factors can affect vitamin D levels in plasma. In present study we compare vitamin D levels of outpatients, who admit to Maltepe University Hospital between 2011 and 2013 and had vitamin D measurements regarding gender, age, and season.

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Aim: Human sperm DNA fragmentation is one of the factors suggested for male infertility. The ratio of sperm DNA damage in semen may adversely affect both the fertilization rate and the embryo development of in vitro fertilization/ intracytoplasmic sperm injection cycles. Sperm cryopreservation both increases the success rates in assisted reproductive techniques (ARTs) and contributes to the preservation of fertility before testis surgery, chemotherapy, and radiotherapy.

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Ischemia-reperfusion (I/R) injury induces the generation of reactive oxygen species (ROS) which affect many organs. This study was designed to investigate the roles of melatonin and 1,25-dihydroxyvitamin D3 (VD3) on renal I/R injury. Thirty male Wistar albino rats were divided into five groups: group 1, control; group 2, right nephrectomy (RN) +  I/R in the contralateral kidney; group 3, melatonin + RN + I/R; group 4, VD3 + RN + I/R; and group 5, melatonin + VD3 + RN + I/R.

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Objective: To compare the efficacy of ozone with melatonin, shown as the most powerful antioxidant in attenuation of testicular ischemia/reperfusion injury, in an experimental rat model of testicular torsion/detorsion.

Methods: Twenty-four male Wistar rats were divided into 4 groups: sham-operated, torsion/detorsion, torsion/detorsion plus melatonin, and torsion/detorsion plus ozone. Melatonin (10 mg/kg) and ozone (4 mg/kg) were intraperitoneally injected daily beginning 15 minutes before detorsion for the following 7 days.

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Oxidative stress is an important factor for aging. The antioxidative enzymes glutathione peroxidase (GPx), glutathione reductase (GRd) and superoxide dismutase (SOD) play a crucial role protecting the organism against the age-dependent oxidative stress. Glutathione (GSH) is present in nearly all living cells.

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This study was designed to evaluate the preventive role of melatonin (Mel) and 1,25-dihydroxyvitamin D3 (VD3) in biochemical and apoptotic events leading to tissue injury and renal dysfunction after ischemia-reperfusion (I/R). Thirty male Wistar rats were divided into five groups: sham-operated, I/R, Mel + I/R, VD3 + I/R, and Mel + VD3 + I/R. The rats were intraperitoneally administered with Mel (10 mg/kg), VD3 (0.

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The aim of this review is to update the reader as to the association between physical exercise and melatonin, and to clarify how the melatonin rhythm may be affected by different types of exercise. Exercise may act as a zeitgeber, although the effects of exercise on the human circadian system are only now being explored. Depending on the time of the day, on the intensity of light, and on the proximity of the exercise to the onset or decline of the circadian production of melatonin, the consequence of exercise on the melatonin rhythm varies.

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Melatonin (MEL) is synthesized mainly in the pineal gland and derived from 5-hydroxytryptophan (5-HTP). Zinc (Zn) is one of the most important trace elements in the body. Zn and MEL levels are changed with aging.

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The purpose of this study was to examine whether the serum levels of nitric oxide end products and the ratio of nitrite to lipoproteins are valid instruments in the clinical follow-up of patients with coronary artery disease. 65 subjects were divided into three groups, including patients with coronary artery disease, silent coronary artery disease and controls. The serum nitrite level and also the ratio of nitrite to high-density lipoprotein were significantly different between the groups.

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Nitric oxide is synthesized from L-arginine by endothelial nitric oxide synthase encoded by eNOS gene. This study was performed to investigate the relationship between the serum nitric oxide level and eNOS gene polymorphism in the Turkish population with angiographically diagnosed coronary artery disease (63.47 +/- 9.

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Although the interaction between Hcy, NO(2)(-) and vascular disease has been extensively studied, there are no data verifying their ratios to HDL-C in coronary artery disease (CAD). We examined whether Hcy/HDL-C and NO(2)(-)/HDL-C ratios correlated with the degree of stenosis in CAD. Also, TC/HDL-C and LDL-C/HDL-C ratios were evaluated in the same individuals.

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Nitric oxide (NO) is a free radical that is produced by a number of mammalian cell types from L-arginine and a critical mediator that acts in many tissues to regulate a diverse range of physiological processes. The major metabolic end product for NO is nitrate (NO(3)) and nitrite (NO(2)), which are stable metabolites within tissue, plasma, and urine. Measurements of nitrate and nitrite values reveal alterations in NO production.

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The objective of this study was to determine the role of cerebral nitric oxide and its powerful oxidant peroxynitrite following mild birth asphyxia. The cerebrospinal fluid levels of nitric oxide and 3-nitrotyrosine as a marker for peroxynitrite are measured in neonates with mild hypoxic-ischemic encephalopathy. Based on the classification of Sarnat and Sarnat, term neonates with mild hypoxic-ischemic encephalopathy and neurologically normal neonates suspected of sepsis were taken as the control group.

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Recently, angiogenesis has gained an increasing interest as a prognostic factor in a variety of solid tumours. In this study we aimed to assess the prognostic role of serum vascular endothelial growth factor (VEGF), basic fibroblast growth factor (b-FGF) and nitric oxide (NO) levels in patients with colorectal carcinoma (CRC).A total of 52 consecutive colorectal cancer patients with stage I to IV disease was included.

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Nitrogen monoxide (NO) is a potent endogenous vasodilator and is involved in cytotoxicity, neurotransmission, and immunological defense mechanisms. Phototherapy has long been known to change the distribution of blood flow throughout the body in newborn infants. The objective of this study was to investigate the effect of phototherapy on NO production in otherwise healthy newborns.

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