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Öğe Bupivacaine and ropivacaine: Comparative effects on nerve conduction block(PROUS SCIENCE, SAU-THOMSON REUTERS, 2007) Bariskaner, H.; Ayaz, M.; Guney, F. B.; Dalkilic, N.; Guney, O.Unlike other drugs which act in the region of the synapse, local anesthetics are agents that reversibly block the generation and conduction of nerve impulses along a nerve fiber. This study aims to investigate the comparative inhibitions of bupivacaine and ropivacaine on the frog sciatic nerve. Isolated nerves were transferred to the nerve chamber which includes Ringer's solution. The nerves were stimulated by), standard square wave pulse protocols and the responses were recorded with conventional systems. Bupivacaine (n = 8) and ropivacaine (n 8) were administered in the nerve chamber both with cumulative concentrations (10(-9) to 10(-3) M) and the effects were monitored for variable time periods (5. 10 and 15 min). Both bupivacaine and ropivacaine significantly depressed the compound action potential (CAP) parameters in a dose-dependent (p < 0.05) and reversible manner. Difference in the eftects of these two drugs was detectable only when the dose (>= 10(-5) M) and exposure time (15 min) were increased. Percent inhibitions in maximum derivatives and latency-period measurements have shown that ropivacaine is not only fast but also much more powerful in conduction block for longer and higher doses. Blipivacaine, on the other hand, is effective in the group of fibers with relatively slower conduction velocity for all the measured doses and time periods. In conclusion, ropivacaine has a sensory specific side of action, when compared with the bupivacaine. (c) 2007 Prous Science. All rights reserved.Öğe Early results of non-fusion dynamic stabilization with InterS(EDIZIONI MINERVA MEDICA, 2011) Kaptan, H.; Kasimcan, O.; Birler, S.; Ayaz, M.Aim. The current study aims to investigate the early out comes of the new technique applied to degenerative spinal disc disease (DSDD) patients. For this purpose 25 patients having DSDD, spinal stenosis and spondilolisthesis were included in the study. The treatments were performed on a two-stage procedure, first surgically with laminectomy, discectomy (when needed) and then the low invasive non-fusion dynamic stabilization with InterS. Methods. The outcomes of the procedure has been followed up for 12 months. Patients were followed up by means of clinical and radiographic techniques. All of the three group of patients underwent a midline decompressive laminectomy with foraminotomies at the effected levels. Furthermore, in lumbar disc hernia cases, discectomy was performed. Oswestry pain scale was used for the clinical evaluation. Results. The study included patients from both sexes (16 females, 9 males) with a mean age of 54.45 years (range 37-68). Symptoms and signs included pain (100), 15 patients have DDD, 7 patients have spinal stenosis, 3 patients spondylolisthesis. Localization was as follows: L3-4: 5 (20%), L4-5: 20 (80%). Satisfactory results were demonstrated in 21 (84%) patients. The average of Oswestry scores was 42.15 in the preoperative period and 8.8 in the postoperative period. Conclusion. Non-fusion dynamic stabilization method of InterS type is a safe procedure. We believe this technique may reduce higher complication rates for patients with spinal stenosis and spondylolysthesis, degenerative disc disease. Motion preservation, early mobilization, short hospital stays and shorter recovery are the main advantages of the operation.Öğe The effects of estradiol on cardiac muscle electrophysiology in orchiectomized rat model: a new insight to side effects caused by castration(VERDUCI PUBLISHER, 2015) Ayaz, M.; Akand, M.; Kucukbagriacik, Y.; Dursunoglu, D.OBJCTIVE: Although the testosterone has a protective effect on heart, patients having maximal androgen blockade due to prostate cancer resembles endothelial dysfunction and cardiac problems when compared to normal population. We aimed to test the effect of 17 beta estradiol on the orchiectomized male rat heart electrophysiology and ion channel expression levels. MATERIALS AND METHODS: This study was conducted on 27 male rats with 4 groups (healthy, orchiectomized, orchiectomized+ 17 beta estradiol treated and orchiectomized+ vehicle treated). Action potentials and contractions were recorded simultaneously, while expressions of the calcium and potassium ion channels were measured. RESULTS: Testosterone depletion for 4 weeks has caused a significant prolongation in the action potential durations and decrease in maximal contraction force as well as a deceleration. While this depletion suppressed expression of potassium channels, it increased the expression of calcium ion channels. Application of estradiol on the other hand, except for the calcium ion channel expression, had no positive effect on the tested parameters. CONCLUSIONS: Testosterone has a markedly important and protective effect on male cardiac muscle preparations while estrogen does not have any. It is predicted that testosterone has showed this effect by means of modulation of some key points of excitation-contraction pairing of cardiac muscle.Öğe EFFECTS OF MELATONIN SUPPLEMENTATION ON EXERCISE-INDUCED CHANGES IN CONDUCTION VELOCITY DISTRIBUTIONS(PROUS SCIENCE, SA, 2009) Ayaz, M.; Okudan, N.The mammalian nervous system processes complex information to control complex behaviors. Since the speed of transport of information can be a life-saving phenomenon, it is extremely important to stabilize the rate of these processes. This study aims to investigate the protective effects of melatonin supplementation on acute heavy exercise-induced changes in the nerve conduction velocity distributions (CVD). Remodeling of the sciatic nerve due to heavy exercise demonstrates not only on increase in some parameters (rheobase and chronaxie), but also decreases in maximum depolarization, total area under the compound action potential (CAP), fall-down phase of CAP kinetics and speed of the intermediately conducting group. Acute heavy exercise-induced decreases in the contribution of nerve fibers were mainly found between 1.0 and 1.7 interstimulus interval (ISI) values (46-52 m/s). Presupplementotion with melatonin, a powerful antioxidant for nervous tissues, protects the sciatic nerve against off of the aforementioned changes. Presupplementotion not only protects the nerve cells from exercise-induced damage, but also increases the contribution of nerve fibers with conduction velocities of 46-52 m/s.Öğe Protective effect of distillated Nerium oleander on heart of type 2 diabetic rats(COMENIUS UNIV, 2015) Ayaz, M.; Baba, Fevzi; Akgün, N.; Baş, Ahmet Levent; Üney, Kamil; Dik, BurakOBJECTIVES: The current study aims to investigate the possible role of NO distillate either for therapeutic or for protective potential in diabetic cardiomyopathy. BACKGROUND: Protective and restorative effects of distillated Nerium oleander (NO) on the diabetes-induced electrophysiological and structural alterations were investigated. METHODS: Type 2 diabetes was induced by combination of single dose streptozotocin injection and high fat diet for four weeks. Experimental groups were designed as follows: control, diabetic, restorative-NO treated diabetic and protective-NO treated diabetic. Intracellular action potentials (AP) and contractile activities were measured form left ventricular papillary muscle strips as well as histopathological examination of heart tissue and biochemical examinations of serum were performed. RESULTS: Type 2 diabetes induced AP prolongation was prevented with both ways of NO treatments. Moreover, treatments produced nearly complete restorations of diabetes-induced depressed amplitude and altered kinetics of contractile activities. In parallel to electrophysiological parameters, both histopathological and biochemical results indicates the NO induced beneficial effects on the diabetes related alterations. CONCLUSION: Distillated Nerium oleander (NO) can be a highly potential therapeutic or preventive agent on the diabetes induced excitation-contraction coupling alterations (Tab. 3, Fig. 3, Ref. 23). Text in PDF www.elis.sk.Öğe The role of gender and sex steroids on the respond of muscle tissue to hypocalcemia(JOHN WILEY & SONS LTD, 2010) Tekin, S.; Kokcam, S.; Sahin, M.; Ayaz, M.; Acar, F.[Abstract not Available]
