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    Biological rhythm of saliva ghrelin in humans
    (Taylor & Francis Ltd, 2006) Aydin, Suleyman; Ozercan, H. Ibrahim; Aydin, Suna; Ozkan, Yusuf; Dagli, Ferda; Oguzoncul, Ferdane; Geckil, Hikmet
    Background: We previously reported that ghrelin in saliva, orexigenic hormone that induces NPY release, was produced and released by salivary glands in humans. The purpose of this study was to investigate a possible circadian rhythm in saliva ghrelin concentration in human subjects as a function of time and meal. Saliva samples were collected at three-hour intervals throughout a 24-h period in 12 healthy volunteer males and ten healthy volunteer females who were provided with meals on a fixed schedule, and saliva collections were made within 15 minutes after each meal. Saliva ghrelin levels were measured by using a commercial radioimmuno assay (RIA) kit that uses I-125-labeled bioactive ghrelin as a tracer and a rabbit polyclonal antibody raised against full-length octanoylated human ghrelin. Immunohistochemical analysis of salivary glands was also performed. The results of this investigation indicated the following. (1) The saliva ghrelin level was slightly higher in female subjects in comparison with male subjects. (2) Saliva ghrelin levels were elevated before each meal and fell to trough levels after eating. (3) Saliva ghrelin levels showed a circadian rhythm that rose throughout the day to a zenith at 0300, then dropped at 0600-0900. (4) Saliva ghrelin also weakly correlated with BMI. (5) Immunohistochemical analysis showed that ghrelin was localized in the striated and excretory ducts of salivary glands of human. The present work is the first report of the circadian rhythm of saliva ghrelin level in human subjects as a function of time and meal. Meal plays an important role in lowering saliva ghrelin concentration in humans. However, present data did not exclude whether the circadian changes in saliva ghrelin expression were regulated by the biological clock or by food intake.
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    Can melatonin correct the negative effect of experimental diabetes created during the maternal period on fetal rat development and puppies cognitive functions?
    (2021) Evren, Bahri; Koz, Sema Tulay; Ozkan, Yusuf; Guldogan, Emek
    Aim: Chronic hyperglycemia can cause cognitive impairments such as learning and memory impairment. In our study, we aimed to investigate the levels of glial fibrillary acidic protein (GFAP), neural cell adhesion molecules (NCAM), lipid peroxidation (LPO), and glutathione (GSH) molecules and the protective effect of melatonin in the brain tissue of baby rats with diabetic mothers. Materials and Methods: Wistar-Albino rats used in the experiments were obtained from Firat University Experimental Research Center. Morris Water Maze Test is a learning and memory test commonly used in rats and mice. In the statistical analysis of the data; one-way analysis of variance (One-way ANOVA) was used to evaluate the significance of NCAM, GFAP, LPO, GSH levels between three groups, and repeated measures analysis of variance (Repeated measures one-way ANOVA) was used to evaluate the Morris Water Maze learning test. Results: Learning was worse in rats whose mothers were diabetic compared to diabetes + melatonin and control groups. With the administration of melatonin to diabetic mothers during their pregnancy, an improvement was observed in the learning ability of baby rats. NCAM 180, GFAP, GSH levels were significantly lower (p <0.05, p <0.001, p <0.05), and LPO level was higher (p <0.001) in baby rats with diabetic mothers compared to the control group. NCAM 180 and GFAP levels were significantly higher in the group that was administered melatonin during pregnancy (p <0.05, p <0.01), and LPO levels were lower (p <0.01). With the administration of melatonin during pregnancy, GSH levels were higher than the diabetes group, even though the difference was not statistically significant. Conclusion: Learning and memory functions are impaired in the offspring of diabetic mothers. The decrease in NCAM isoforms can inhibit brain development and the formation of synaptic plasticity. Decreased GFAP density may pose a problem in completing brain maturation in offspring of diabetic mothers. It has been observed that the administration of melatonin to diabetic mothers during their pregnancy is protective against the harmful effects of oxidative stress in their offspring due to its antioxidant effect.
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    The role of apparent diffusion coefficient values in differentiation between adrenal masses
    (Elsevier Science Inc, 2014) Cicekci, Mehtap; Onur, Mehmet Ruhi; Aydin, Ayse Murat; Gul, Yeliz; Ozkan, Yusuf; Akpolat, Nusret; Kocakoc, Ercan
    The aim of this study was to evaluate the utility of apparent diffusion coefficient (ADC) values in differentiation between solid adrenal masses. The ADC values of 73 adrenal lesions (54 benign, 19 malignant) in 69 patients were measured at b 100, 600 and 1000 gradients on diffusion-weighted magnetic resonance imaging (DW-MRI). No statistically significant difference was found between ADC values of benign and malignant adrenal masses, nonadenomatous benign adrenal masses and malignant adrenal masses, adrenal adenomas and nonadenomatous lesions, adenomas and metastases, adenomas and pheochromocytomas, metastases and pheochromocytomas. ADC values are not helpful in the differentiation between solid adrenal masses. (C) 2014 Elsevier Inc. All rights reserved.