Tıp Fakültesi / Faculty of Medicine
Permanent URI for this collectionhttps://hdl.handle.net/11727/1403
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Item Effects of Hypoxia Versus Ischaemia on Vascular Functions of Isolated Rat Thoracic Aorta: Revisiting the in Vitro Vascular Ischaemia/Reperfusion Model(2023) Orhan, Halit Guner; Teimoori, Ariyan; Demirtas, Elif; Zeynalova, Nargiz; Efe, Oguzhan Ekin; Aydingoz, Selda Emre; 37937174Introduction The in vitro rat vascular ischaemia and reperfusion model is used to evaluate the molecular and functional effects of potential agents against ischaemia and reperfusion injury of autologous graft veins. However, there is no consensus on whether hypoxia, rather than ischaemia, is sufficient to induce vascular dysfunction. Aim To compare the effects of hypoxia and ischaemia, with or without reperfusion, on the vascular functions of isolated thoracic aortic rings of rats. Material and methods Thoracic aortas of 12 male Sprague-Dawley rats (350-500 g, 18-24 months old) were isolated and divided into rings that were randomly allocated to control, ischaemia, hypoxia, ischaemia-reperfusion, and hypoxia-reperfusion groups. Aortic rings other than those of the control group were stored at 4 degrees C for 24 h in saline. For ischaemia, saline was gassed with nitrogen. After 24 h, aortic rings in the ischaemia-reperfusion and hypoxia-reperfusion groups were incubated with 200 mu M sodium hypochlorite for 30 min. Vascular and endothelial functions were tested in an organ bath set-up. Results Vascular response to potassium chloride (80 mM) decreased in all experimental groups compared to the control group (p = 0.007), but phenylephrine-induced contraction (10-5 M) increased only in the ischaemia-reperfusion group (p < 0.0001). Acetylcholine (10-11-10-5 M)-induced endothelium-dependent vasorelaxations were impaired in all groups - particularly in the ischaemia-reperfusion group (p = 0.0011). Sodium nitroprusside (10-12-10-7 M)-induced endothelium-independent vasorelaxations were similar across all groups (p = 0.1258). Conclusions Ischaemia followed by reperfusion should be implanted to achieve maximum endothelial and contractile dysfunction in vitro, and to replicate ischaemia and reperfusion injury of autologous graft veins.Item Association between Hypoxia Parameters with White Matter Hyperintensity and Silent Cerebral Infarcts on Brain Magnetic Resonance Images in Patients with Obstructive Sleep Apnea(2016) Avci, Aynur Yilmaz; Avci, Suat; Lakadamyali, Huseyin; Lakadamyali, Hatice; Can, Ufuk; 0000-0003-2155-8014; 0000-0001-9004-9382; 0000-0001-8689-417X; O-3636-2018; F-6770-2019; AAJ-2999-2021Objective: This study evaluated the association between hypoxia parameters with white matter hyperintensity (WMH) and silent cerebral infarcts (SCI) on brain magnetic resonance (MR) images of patients with obstructive sleep apnea (OSA). Methods: In this retrospective study, the study group was composed of 453 patients who were evaluated by overnight polysomnography (PSG). Data on hypoxia parameters, such as total sleep duration with oxygen saturation < 90% (ST90), percentage of cumulative time with oxygen saturation < 90% (CT90), and the lowest oxygen saturation (min SaO(2)), were obtained from PSG. The presence of WMH and SCI was evaluated in all participants using brain MR images. Results: Hypoxia parameters, such as ST90, CT90, and min SaO(2), were significantly associated with WMH (P < 0.001). The multiple regression analysis showed that CT90 was independently associated with SCI (P = 0.038). In addition, when participants were divided into two groups according to CT90 < 10% and CT90 = 10%, age (P = 0.002), sex (P = 0.015), body mass index, Apnea-Hypopnea Index score, Epworth Sleepiness Scale score, and the presence of WMH, hypertension, and diabetes mellitus were significantly higher in the CT90 = 10% group compared with the CT90 < 10% group (P < 0.001 for all parameters). CT90 = 10% increased the risk of WMH 2.34-fold (95% confidence interval, 1.44-3.85; P = 0.006). Conclusion: The severity of nocturnal intermittent hypoxia may contribute to the pathogenesis of WMH and SCI in patients with OSA.Item Does Ginkgo biloba Protect Developing Testes from Chronic Hypobaric Hypoxia?(2017) Gul, Elif Ensari; Kaplanoglu, Gulnur Take; Helvacioglu, Fatma; Kaplanoglu, Iskender; Seymen, Cemile Merve; 0000-0002-6026-0045; 0000-0002-8945-3801; AAH-8887-2021; AAS-5415-2021OBJECTIVE: To evaluate the potential protective effects of Ginkgo biloba on developing testes exposed to chronic hypobaric hypoxia during their prenatal life. STUDY DESIGN: Twelve pregnant Wistar albino rats on the fifth gestational day were placed in hypoxic chambers for the upcoming 15 days. Six pregnant female rats were kept under normal atmospheric conditions during the pregnancy as a control group. The study groups were as follows: Control, Hypoxia, and Hypoxia + Ginkgo biloba. Ginkgo biloba was administered for each designated postnatal sacrifice day. For the Hypoxia + Ginkgo biloba group, after birth, 100 mg/kg of Ginkgo biloba extract was administrated orally to the newborn male rats. Testes tissues were sampled on postnatal days 7, 14, and 21 from each group, and PCNA, TUNEL, and TEM examinations were performed. RESULTS: PCNA immunoreactivity was decreased and TUNEL positive cell number was increased in the hypoxic group. TEM examination revealed degenerative changes in hypoxic group testes tissue. Hypoxia changed the cell cycle in spermatogenic series by reducing proliferation and increasing apoptosis. Spermatogenic cell degeneration and high Leydig cell activity were determined in the hypoxia group by TEM examinations. CONCLUSION: We believe that Ginkgo biloba has protective effects on testes tissue, especially in long-term use.Item Peripheral Nerve Function Changes Due to Hypoxia in Obstructive Sleep Apnea(2019) Avci, Aynur Yilmaz; Avci, Suat; 0000-0001-9004-9382Introduction: Chronic hypoxia is known to be one of the risk factors for peripheral neuropathy. However, the effect of intermittent hypoxia on peripheral nerves is not fully understood. This study evaluated the relation between intermittent hypoxia and peripheral nerve function in Obstructive Sleep Apnea (OSA) patients. Materials and Methods: In this retrospective study, 86 patients who underwent polysomnography (PSG) and electroneuromyography were enrolled. Participants with diseases affecting peripheral nerves and lung function were excluded from the study. Hypoxia parameters were obtained from the PSG study. Lower extremity motor and sensory nerve conduction studies of all patients were evaluated. Results: In patients with OSA, peroneal nerve distal motor latency and sural sensory nerve action potential amplitude was low and velocity was significantly slower than controls (p<0.001, p<0.04, p<0.001, respectively). After adjustment for age and body mass index, the results remained significantly (p<0.001, p<0.01, p<0.001, respectively). The nerve conduction results were significantly correlated with the hypoxia parameters. After adjustment for confounding factors, logistic regression analyses revealed that hypoxia parameters were independently associated with nerve conduction results. Conclusion: OSA and intermittent hypoxia may affect both motor and sensory nerve conduction, which suggests that subclinical sensorimotor peripheral neuropathy is associated with OSA. The related intermittent hypoxia and OSA may be a cause of axonal and demyelinating neuropathies.