Browsing by Author "Ozbek M."

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    Histophysiological effects of fluid resuscitation on heart, lung and brain tissues in rats with hypovolemia
    (Elsevier GmbH, 2006) Ekerbicer N.; Inan S.; Tarakci F.; Cilaker S.; Ozbek M.
    The efficacy of using colloids and crystalloids in the treatment of hypovolemia still remains controversial. An important aspect in treating hypovolemia is to re-establish normal tissue hemodynamics after fluid resuscitation. Production of nitric oxide (NO) or growth factors such as transforming growth factor beta (TGF-β) has been identified as a key mechanism in physiological and pathological processes in the different systems. This study was designed to investigate the histophysiological effects of resuscitation with different plasma substitutes on the heart, lung and brain tissues following acute blood loss in male Sprague-Dawley rats weighing 250-280 g (n=30). After anesthesia with sodium pentobarbital, the left femoral vein and artery were cannulated for the administration of volume expanders and for direct measurement of arterial pressure and heart rate. Twenty rats were bled (5 ml/10 min) and infused (5 ml/10 min) with one of four randomly selected solutions, (a) human albumin, (b) gelatin (Gelofusine), (c) dextran-70 (Macrodex); or (d) physiological saline (0.9% isotonic saline). Five control rats were bled without infusion. Tissue samples were taken and fixed in 10% formalin solution, then processed for embedding in paraffin wax. Sections were cut and stained with hematoxylin and eosin. Indirect immunohistochemical labelling was performed to reveal binding of primary antibodies against endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS) and TGF-β. Mild immunoreactivity of eNOS was observed in endothelial cells of vessels in brain, heart and lung tissues. Increased immunoreactivities of eNOS, iNOS and TGF-β were observed in the non-fluid resuscitated group in these organs; mild, moderate, moderate and strong immunoreactivities were seen in the albumin, gelatin, physiological saline and dextran-70 treated groups, respectively. Immunoreactivities of iNOS and TGF-β in the non-fluid resuscitated group were increased significantly, in comparison to the other groups, apart from the dextran-70 treated group. The results of this study show that gelatin solution and physiological saline may be of use after acute blood loss, and dextran-70 is not the preferred resuscitation fluid in the early stages of acute blood loss. It was concluded that albumin solution is the preferred fluid for resuscitation. © 2006 Elsevier GmbH. All rights reserved.
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    Effects of acute treatment with dexamethasone on hemodynamic and histopathological changes in rats
    (2012) Ekerbiçer N.; Inan S.; Tarakç F.; Barut T.; Gürpnar T.; Ozbek M.
    We assessed the time-dependent effects of intraperitoneal (i.p.) and intravenous (i.v.) application of dexamethasone (Dexa) on the mean arterial blood pressure (MAP), heart rate (HR) and total blood volume (TBV). We evaluated also the relation between the effects and immunoreactivities of transforming growth factor-beta (TGF-β), epithelial nitric oxide synthase (eNOS), interleukin-1 beta (IL1-β) and vascular endothelial growth factor (VEGF) in rat brain, lung and kidney tissues. Rats were anesthetized and while still breathing spontaneously, a tracheotomy and femoral vein and artery catheterizations were performed. To determine TBV using the hemodilution method, 2 ml albumin-electrolyte solutions were applied by i.v. injection. Group 1 (control group) received a 1 ml bolus injection of physiologic saline, Group 2 received 15 mg/kg and Group 3 received 75 mg/kg Dexa i.p. The hematocrit was measured at 10, 20, 60 and 120 min. For each animal, the values of MAP, HR and TBV were measured within 2 h. For immunohistochemical evaluation, anti-TGF-β, anti-eNOS, anti-IL1-β and anti-VEGF primary antibodies were tested using the avidin-biotin-peroxidase method. TBV was decreased in Group 1 and the increase in MAP was statistically significant. HR values increased slightly. None of the values changed significantly in Group 2. Although TBV was unchanged in Group 3, the decrease in MAP was statistically significant. HR values increased, but the increase was not statistically significant. Mild IL1-β immunoreactivity and moderate TGF-β, eNOS and VEGF immunoreactivities were observed in the brain, lung and kidney samples in Group 1. Increased eNOS immunoreactivity in the kidney samples were observed in Group 2. eNOS immunoreactivity was as strong in the brain and the kidney samples in Group 3. Decreased VEGF immunoreactivity was observed in the lung and kidney tissues in Group 3. Significantly decreased TGF-β immunoreactivity was observed in all tissue samples in Group 3. The decreased MAP values in Group 3 differed from those in Groups 1 and 2. Despite increased eNOS immunoreactivity, especially in brain and kidney, the decrease in VEGF immunoreactivity in Group 3, especially lung and kidney, were consistent with a drop in blood pressure. © 2012 The Biological Stain Commission.
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    The effects of melatonin and thymoquinone on doxorubicin- -induced cardiotoxicity in rats
    (Comenius University in Bratislava, 2020) Yildiz Pehlivan D.; Durdagi G.; Oz Oyar E.; Akyol S.; Ozbek M.
    OBJECTIVES: This study aims to investigate the protective effects of thymoquinone and melatonin on the heart against doxorubicin-induced cardiotoxicity in rats. BACKGROUND: Melatonin and thymoquinone may play an important role in cardiotoxicity. METHODS: The subjects were divided into four groups: Control (physiological serum on 5th day), Doxorubicin (DXR), Doxorubicin+Melatonin (DXR+MEL, 10 mg/kg melatonin, intraperitoneally), and Doxorubicin+Thymoquinone (DXR+TQ, 50 mg/kg thymoquinone, orally). On the 5th day of the experiment, all groups were injected with 45 mg/kg DXR into the tail vein. On the 8th day of the experiment, ECG recordings were performed under anaesthesia. RESULTS: Thymoquinone reduced the PR, QRS and QTc intervals, which were increased by DXR, while melatonin only reduced the QTc interval. Melatonin had a protective effect against the histopathological changes induced by DXR, while TQ did not demonstrate such an effect. DXR increased CK-MB, IL-6, MDA, IL-1, IL-18 levels and decreased SOD in the cardiac tissue. MEL reduced the levels of CK-MB, MDA, NO, SOD, IL-1, IL-6, IL-18. Meanwhile, TQ only reduced CK-MB, IL-1 and IL-18. CONCLUSION: Our study showed that DXR induces cardiac injury and that melatonin improves biochemical parameters and offers histological protection; while thymoquinone improves ECG parameters and causes partial recovery of biochemical parameters (Tab. 4, Fig. 2, Ref. 41). Text in PDF www.elis.sk. © 2020.
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    Effects of Melatonin and Adrenomedullin in Reducing the Cardiotoxic Effects of Doxorubicin in Rats
    (Springer, 2021) Durdagi G.; Pehlivan D.Y.; Oyar E.O.; Bahceci S.A.; Ozbek M.
    The main disadvantage of doxorubicin (DOX) is that it has cardiotoxic side effects. Our aim is to evaluate the cardioprotective effects of adrenomedullin (ADM) and to compare these effects with melatonin (MEL), it’s cardioprotective effects are well known. Rats were divided into four groups: Control group (0.9% NaCl solution, intravenously), Doxorubicin group (45 mg/kg DOX, intravenously), Doxorubicin + Melatonin group (DOX + MEL, 10 mg/kg melatonin, intraperitoneally), Doxorubicin + Adrenomedullin group (DOX + ADM, 12 µg/kg adrenomedullin, intraperitoneally). A single dose of DOX was injected to the experimental groups on day 5, and a single dose of 0.9% NaCl solution was injected to the control group through the tail vein. The animals were anesthetized and ECG recordings were obtained on day 8. For the purpose of biochemical and histological analysis, cardiac tissue biopsy was obtained after ECG recordings. Compared to the control group, the DOX group had significantly increased duration of QRS complex, PR interval, QT interval and QTc interval. QRS complex, QT interval and QTc interval were prolonged with the administration of DOX and shortened with the administration of ADM. MEL weakened the toxic effects of DOX on the cardiac tissue and it is shown histologically. DOX increased interleukins (IL-1α, IL-6, IL-18), tumor necrosis factor-α (TNF-α), hypoxia-inducible factor 1-alpha (HIF-1α), malondialdehyde (MDA), nitric oxide (NO), creatine kinase myocardial band (CK-MB), and total oxidant status (TOS) levels in cardiac tissue, while reducing total antioxidant status (TAS), superoxide dismutase (SOD) and catalase (CAT) levels. MEL administration decreased the levels of CK-MB, MDA, IL-1α, IL-6, IL-18, NO, and TNF-α, whereas ADM only decreased IL-1α, IL-18, MDA and TNF-α levels. In summary, these results show that DOX has toxic effects on rat cardiac tissue which is documented histologically, electrocardiographically and biochemically. MEL alleviated histological damage and showed improvement on the several biochemical parameters of cardiac tissue. ADM brought several electrocardiographic and biochemical parameters closer to normal values. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.
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    Electrophysiological detection of exam stress in health schools' students
    (Akademiai Kiado ZRt., 2024) Kazdagli H.; Ozel H.F.; Ozturk S.; Ceylan D.; Erdeniz B.; Ozbek M.; Semin M.I.
    Anxiety is a common issue among university students, many of them experience anxiety, depression, and stress during their school life. This study aimed to compare the acute physiological stress responses of students divided into two groups according to their perceived anxiety levels (positive test anxiety, PTA+, and negative test anxiety, PTA-). Heart rate variability (HRV) and electrodermal activity (EDA) were used to assess stress. Thirty-one healthy volunteers participated in the study. Participants completed anxiety assessments, including the Westside Test Anxiety Scale (WTAS), the State-Trait Anxiety Inventory (STAI), and the Test State Anxiety Inventory (TSAI). Based on their scores, participants were categorized into PTA+ and PTA-groups. All participants underwent 24-h continuous recordings of pulse and electrodermal activity (EDA) on two separate occasions: one day prior to a written exam and during a designated exam-free day serving as a baseline control. We compared the HRV and EDA data obtained on a regular day and on an exam day between the two groups. Results showed that the PTA+ group had significantly higher heart rate, stress index, low frequency, and short-Term detrended fluctuation analysis (DFAα1) on the exam day. The tonic EDA component was also higher in the PTA+ group. Stress-related HRV and EDA parameters were negatively correlated with exam scores. In conclusion, the study found that physiological stress indicators obtained from HRV and EDA are associated with perceived exam anxiety in students. © 2024 Akadémiai Kiadó, Budapest.
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    Right vagotomy alters heart rate variability temporarily and increases total choline levels in rats
    (Walter de Gruyter GmbH, 2024) Kazdagli H.; Baris E.; Ozel H.F.; Ozbek M.
    Objectives: The variability in the time intervals between heartbeats, known as heart rate variability (HRV), serves as a reflection of the intricate interplay between the sympathetic and parasympathetic neural systems. While the potential asymmetric effects of the left and right branches of the vagus nerve remain uncertain, this study aims to investigate the impact of unilateral, bilateral, and atropine interventions on HRV parameters and choline levels within cardiac tissue. Methods: 40 male adult Wistar albino rats were randomly assigned to the five groups (each n=8): sham-operated, atropine, right vagotomy, left vagotomy, and bilateral vagotomy. Heart rate variability (HRV) analyses were conducted, and the levels of total choline/acetylcholine in heart tissues were quantified. Statistical analyses were performed to assess the results. Results: The bilateral vagotomy and atropine groups exhibited higher heart rates and high frequency power (HF), along with reduced low frequency power (LF). Total power (TP) remained relatively unchanged. In the bilateral vagotomy group, DFAα1 was significantly elevated while DFAα2 was reduced significantly. SD1 and SampEn were significantly lower in both the bilateral vagotomy and atropine groups. Notably, the right vagotomy group displayed significant changes primarily in the 15th minute, particularly in time-domain parameters, HF, TP, and SD1, with a significant increase observed in total choline levels. Conclusions: Our results revealed that asymmetrical vagal innervation induces distinct effects on heart rate variability parameters and total choline/acetylcholine levels in heart tissues. Our findings suggest that compensatory hemodynamic recovery, possibly driven by contralateral vagal overactivity, may contribute to these observed results. © 2024 the author(s), published by De Gruyter.