Hüseyin Beydagi

Determination of preferred walking speed on treadmill may lead to high oxygen cost on treadmill walking.

The energy consumption of walking relates to the intensity of physical effort and can be affected by the alterations in walking speed. Therefore, walking speed can be accepted as a crucial, determinant of energy consumption measurement for a walking test. We aimed to investigate the differences in preferred walking speed (PWS) determined both on overground and on a treadmill and, to measure walking energy expenditure and spatio-temporal parameters of gait on a treadmill at both, speeds. Participants (n=26) walked on a treadmill at two pre-determined speeds for 7 min while, indirect calorimetry measurements were being performed. Spatio-temporal parameters were collected, by video-taping during each walking session on a treadmill. The average overground preferred walking speed (O-PWS) was 85.96+/-12.82 m/min and the average treadmill preferred walking speed (T-PWS), was 71.15+/-13.85 m/min. Although T-PWS was lower, oxygen cost was statistically higher when, treadmill walking at T-PWS (0.158+/-0.02 ml/kg/m) than when the treadmill walking at O-PWS, (0.1480+/-0.02 ml/kg/m). Cadence (127+/-9.13 steps/min), stride (134.02+/-14.09 cm) and step length (67.02+/-6.90 cm) on the treadmill walking at O-PWS were significantly higher than cadence (119+/-10 steps/min), stride (117.96+/-14.38 cm) and step length (59.13+/-7.02 cm) on the treadmill walking at TPWS. In conclusion, walking on treadmill using O-PWS is more efficient than walking on treadmill using TPWS, in walking tests. Since using T-PWS for treadmill walking tests overestimates the oxygen cost of walking, O-PWS should be used for oxygen consumption measurement during treadmill walking tests.

Neuroprotective effect of levetiracetam on hypoxic ischemic brain injury in neonatal rats

PurposeHypoxic-ischemic brain injury that occurs in the perinatal period is one of the leading causes of mental retardation, visual and auditory impairment, motor defects, epilepsy, cerebral palsy, and death in neonates. The severity of apoptosis that develops after ischemic hypoxia and reperfusion is an indication of brain injury. Thus, it may be possible to prevent or reduce injury with treatments that can be given before the reperfusion period following hypoxia and ischemia. Levetiracetam is a new-generation antiepileptic drug that has begun to be used in the treatment of epilepsy.MethodsThe present study investigated the effects of levetiracetam on neuronal apoptosis with histopathological and biochemical tests in the early period and behavioral experiments in the late period.ResultsThis study showed histopathologically that levetiracetam reduces the number of apoptotic neurons and has a neuroprotective effect in a neonatal rat model of hypoxic-ischemic brain injury in the early period. On the other hand, we demonstrated that levetiracetam dose dependently improves behavioral performance in the late period.ConclusionsBased on these results, we believe that one mechanism of levetiracetam’s neuroprotective effects is due to increases in glutathione peroxidase and superoxide dismutase enzyme levels. To the best of our knowledge, this study is the first to show the neuroprotective effects of levetiracetam in a neonatal rat model of hypoxic-ischemic brain injury using histopathological, biochemical, and late-period behavioral experiments within the same experimental group.

Slow cortical potential shifts modulate P300 amplitude and topography in humans

Effects of the spontaneous slow cortical potential (SCP) shifts of the electroencephalogram (EEG) on the P300 response were investigated on ten healthy volunteers. P300 responses were recorded using an auditory oddball paradigm, where target stimuli were presented regularly after every four standard stimuli. Single event-related potential (ERP) sweeps exhibiting negative or positive SCP shifts were averaged separately. The P300 amplitude was significantly larger during negative SCP shifts. Furthermore, the topographies of P200 and P300 waves obtained during negative and positive SCP shifts showed significant differences. The results indicate that the SCP shifts in single ERP sweeps, which are considered to be correlated with the arousal or basic activity level of the cortex, explain at least part of the inter-trial variability of P300 response.

The Relation Between Event Related Potential and Working Memory in Healthy Subjects

In numerous investigations the P300-component of the event related potential has proved a valid indicator of memory activities. The present study explores the amplitude and latency of the components of event-related potential regarding short-term memory task. Event related potentials, elicited by auditory stimuli, were recorded in 40 healthy subjects. For evaluating short term memory capacity of a subject, software in Delphi for Windows language was written. Algorithm of the software was the presentation of randomly selected four different digits for 4 seconds, removing it and waiting for subjects response, adding one digit, if response was true, otherwise decreased by one. After 20 trials, mean of recall time for true answers was computed. The subjects with high recall time showed prolonged latency of P300. A positive correlation was found between P300 latency and recall time. No correlation was found between N1, P2 and N2 latency or amplitude and recall time. These results suggest that memory problems are well correlated with the abnormalities of P300.

The effect of direction on saccadic eye movement parameters.

The present study obtained saccadic eye movements from 25 right-handed normal subjects (aged 18-35 yr, mean 22.4 yr) to examine the effects of saccade direction on saccadic parameters (latency, duration and average velocity). Binocular saccadic eye movements were recorded with a direct-current electrooculographic system, and analysis was performed on a laboratory digital computer. The LED target positions were randomly selected 10, 15, 20, 25 and 30 degrees to the left or right of the fixation points. In general, the mean values of the saccadic parameters over large saccade angles were in agreement with those previously reported. There were no significant differences between saccades directed to the right and to the left.

Fibromyalgia Syndrome Patients Optimize the Oxygen Cost of Walking by Preferring a Lower Walking Speed

Objectives The aim of the study is to investigate the effect of fibromyalgia syndrome [FMS] on the preferred walking speed [PWS], energy expenditure at rest, and oxygen cost of walking. Methods Fifteen women with FMS and 15 healthy matched female subjects participated in our study. All patients were newly diagnosed and had no medication for FMS. The energy expenditure of FMS individuals was measured by using indirect calorimetry during resting and walking at PWS. Results The resting energy expenditure in healthy subjects [Group 1] was 1115.08 ± 154.33 kcal/day and that in FMS patients [Group 2] was 1253.48 ± 212.94 kcal/day; there was no statistical difference between the groups [P > 0.05]. The mean PWSs in Groups 1 and 2 were 81.22 ± 9.10 and 71.42 ± 6.61 m/min, respectively. The difference between the PWSs in Groups 1 and 2 was statistically significant [P < 0.05]. The mean oxygen consumption in the first walking trail was 12.95 ± 2.62 and 11.83 ± 1.68 mL/kg/min in Groups 1 and 2, respectively [P > 0.05]. The mean oxygen cost of the first walking trial in Groups 1 and 2 was 0.16 ± 0.02 and 0.17 ± 0.02 mL/kg/m, respectively; the difference was not significant [P > 0.05]. Conclusion The PWS of patients with FMS was lower than that of healthy controls. The oxygen cost and consumption were similar in both groups in our study. This study demonstrates that FMS individuals optimize the oxygen cost of walking by preferring a lower walking speed.

The effects of fibroblast growth factor-2 and pluripotent astrocytic stem cells on cognitive function in a rat model of neonatal hypoxic-ischemic brain injury.

Abstract Objective: This study aimed to determine the effect of pluripotent astrocytic stem cells (PASCs) and fibroblast growth factor-2 (FGF-2) on cognitive function in neonatal rats with hypoxic-ischemic brain injury (HIBI). Methods: The study was performed on 7-d-old rats that were randomly divided into four groups. All rats, except those in the sham group, were kept in a hypoxic chamber containing 8% oxygen for 2 h after the ligation of the right carotid artery. Next, 5 d after HIBI was induced, PASCs were administered to the motor cortex, and FGF-2 was administered intraperitoneally to group AF; PASCs were administered to the motor cortex, and salt solution buffered with phosphate was administered intraperitoneally to group A; and fresh cell culture solution (medium) was administered to group M. Immunofluorescence was used to localize the administered PASCs in the brains of rats from groups A and AF. The Morris water maze tank (MWM) test was performed to assess the rats’ cognitive functions at week 12. The rats that were administered PASCs were observed for the development of neoplasms and autopsies were performed after 30 months. Results: PASCs migrated to damaged brain regions surrounding the hippocampus in groups A and AF. The mean platform finding time (PFT) significantly decreased over time in each group on day 1–4 of MWM testing (p < 0.001). On day 2–4, the mean PFT was shortest in group S followed by group AF. In group A, the PFT was significantly longer than in group S on day 3–4 (p = 0.01 and 0.007, respectively). On day 5 of the MWM test, the time spent in the eastern quadrant (which previously contained the platform) was longest in group S followed by groups AF, A, and M; however, the differences between groups were not significant (p = 0.51). After 30 months, none of the rats in groups A or AF had benign or malignant neoplasms. Conclusions: Following the administration of PASCs in rats with experimentally induced HIBI, PASCs migrated to the injured brain regions; however, treatment with PASCs did not have a positive effect on cognitive function. The administration of FGF-2 together with PASCs resulted in positive cognitive results, although not at the level of significance.

Is levetiracetam neuroprotective in neonatal rats with hypoxic ischemic brain injury

BACKGROUND The aim of this study was to determine if levetiracetam (LEV) is neuroprotective in neonatal rats with hypoxic-ischemic brain injury (HIBI). METHODS The study included 7-d-old male Wistar rats that were randomly divided into the LEV400, LEV800, control, and sham groups. All the rats, except those in the sham group, underwent ligation of the carotid artery and were then kept in a hypoxic chamber containing 8% oxygen for 2 h. At the end of the hypoxic period the rats in the control group were administered saline solution 0.5 mL, the rats in the LEV400 group were administered LEV 400 mg.kg-1, and rats in the LEV800 group were administered LEV 800 mg.kg-1 via the intraperitoneal route. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) method was used to evaluate neuronal apoptosis in the rats. The Morris Water Maze (MWM) test was performed at age 14 weeks in order to evaluate cognitive function. RESULTS The number of apoptotic neurons in the right hemispheres was significantly lower in the sham, LEV400, and LEV800 groups than in the control group (p < 0.001, p < 0.001, and p < 0.001, respectively). In addition, the number of apoptotic neurons in the right hemispheres was significantly lower in the LEV800 group than in the LEV400 group (p = 0.001). Platform finding time (PFT) during MWM testing was significantly shorter in the sham and LEV800 groups on d 4 than on d 1 (p = 0.001 and p = 0.006, respectively); however, PFT did not significantly change between d 1 and d 4 in the control or LEV400 groups (p = 0.91 and p = 0.096, respectively). CONCLUSION Based on the present findings, LEV exhibited a dose-dependent neuroprotective effect in neonatal rats with HIBI (Ref. 27).

Resting Energy Expenditure in Normal-Weight and Overweight/Obese Subjects Was Similar Despite Elevated Sympathovagal Balance

Objective: Alterations in the autonomic nervous system (ANS) may cause impairment in the metabolic processes that can lead to weight gain. The purpose of this study was to determine the difference between the resting energy expenditure (REE) and the resting ANS activity in overweight/obese and normal-weight healthy subjects. Method: Group 1 consisted of 18 subjects with BMI > 25 kg/m2, and 20 subjects with BMI ranging from 20 to 25 kg/m2 formed group 2. Measurements of low-frequency (LF) and high-frequency (HF) power components expressed in normalized units (LFnu, HFnu) and LF/HF ratio were assessed for analysis of heart rate variability, and simultaneously REE measurement was performed. Results: The mean LFnu (27.2% increased) and the LF/HF were higher and the mean HFnu was lower (29.9% decreased) in group 1 than in group 2 (p < 0.01). Although a statistical difference was observed in REE between groups, REE per kilogram corrected for fat-free mass (REEFFMcorr) was 21.47 ± 2.92 kcal/day/kg in group 1, and 21.56 ± 1.90 kcal/day/kg in group 2, and this difference was not statistically significant (p > 0.05). Conclusion: We concluded that REEFFMcorr in overweight/obese and normal-weight subjects were similar despite elevated sympathovagal balance in overweight/obese individuals, and REEFFMcorr should be used to avoid misestimating the REE in obese and normal-weight subjects.

Effect of Osteoporosis on Energy Expenditure of Resting and Daily Activities in Postmenopausal Women

Summary Objective: The purpose of our study was to determine the effect of osteoporosis on energy expenditure and daily activities of postmenopausal women. Materials and Methods: Eighteen recently diagnosed postmenopausal osteoporotic women without any fractures participated in this study. They were matched for age and body mass index with 19 postmenopausal nonosteoporotic women. Energy expenditure of postmenopausal women was measured using an indirect calorimetry during resting, sitting, standing and walking at speeds of 50 m/min and 70 m/min. Quality of life of subjects was evaluated with the short form-36 (SF-36) questionnaire. Results: There were no significant differences between groups for VO2 (ml/min) during resting, sitting, standing, and walking at speeds of 50 m/min and 70 m/min. Bone mineral density (BMD) of the proximal femur was correlated with resting energy expenditure (REE) (r=0.49, p= 0.03) in postmenopausal osteoporotic women. The SF-36 bodily pain subscale score was significantly higher in postmenopausal osteoporotic women (74.33±20.86) than in nonosteoporotic women (58.10±17.09). The power of the study for detecting the differences was calculated as 71%. Conclusion: The results seem to indicate that there is a relationship between BMD and REE in postmenopausal osteoporotic women. Although pain scores were higher in osteoporotic women, it was detected that they did not affect the energy expenditure of resting and at different physical activity levels. While determining the caloric intake of osteoporotic women and energy expenditure estimation in various daily physical activities, it can be taken into account that energy expenditure of osteoporotic women is similar to nonosteoporotic women. Turk J Phys