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Abdelrahman, Aly M,Suleimani, Yousuf M Al 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.12
The aim of this study was to examine the effect of chronic administration of nimesulide, a cyclooxygenase-2 inhibitor, on endothelial dysfunction in streptozotocin-induced diabetic rats. Three groups of Sprague-Dawley rats (300-350 g, n = 6) were used. The first group served as normoglycemic control and the second and third groups were rendered diabetic by an intraperitoneal injection of streptozotocin (60 mg/kg). The third group received the selective COX-2 inhibitor, nimesulide (20 mg/kg/day), orally by gavage for 4 weeks while the second group received only drinking water and served as diabetic control. At the end of the treatment period, the rats were anesthetized with urethane (1.2 g/kg) and mean arterial pressure, heart rate and hindlimb blood flow were monitored. This was followed by the injection of acetylcholine (endothelium-dependent vasodilator, $0.1-0.8{\mu}g/kg$) and sodium nitroprusside (endothelium-independent vasodilator $1-4{\mu}g/kg$). Mean arterial pressure was significantly reduced and hindlimb vascular conductance was not significantly affected in the control diabetic group when compared to the normoglycemic control group. Nimesulide treatment did not cause any significant change in any of the measured hemodynamic parameters. Acetylcholine and sodium nitroprusside induced dose-dependent increases in hindlimb vascular conductance in control normoglycemic rats which were attenuated in diabetic control rats. Nimesulide reversed the attenuation of acetylcholine-induced increase in hindlimb vascular conductance. In conclusion, chronic administration of the selective COX-2 inhibitor, nimesulide improved endothelial dysfunction in the hindlimb vasculature of streptozotocin induced diabetic rats. This suggests that COX-2 products might be involved in the pathogenesis of endothelial dysfunction in streptozotocin-induced diabetic rats.
Negative Influence of the Hunger State on Rule-observance Behavior in Mice
Abdelrahman M. Alkahwaji,신희섭,이창준 한국뇌신경과학회 2023 Experimental Neurobiology Vol.32 No.1
Developing social strategies to share limited resources equally and maximize the long-term benefits of conflict resolution is critical for appropriate social interactions. During social interactions, social decision-making depends not only on the external environment, but also on internal factors, such as hunger, thirst, or fatigue. In particular, hunger, which is related to food as a physical need, plays a dominant role in social decision-making. However, the consequences of food deprivation on social decision-making are not well understood. We have previously shown that mice with rule-observance behavior are capable of resolving conflict during social decision-making by observing a well-established social strategy based on reward zone allocation. Here, we developed a rule-observance behavior paradigm wherein the hunger state is achieved by applying food restric- tions on mice prior to social behavior experiments.We found that the hunger state in mice deteriorated the established social strategy by decreasing reaction time, implying an increase in impulsivity. In contrast, the hunger state did not affect reward zone allocation, indicating no effect on spatial memory. This decrease in reaction time led to a significant increase in the percentage of violations during rule observance and a significant de- crease in the amount of reward (payoff equity). Our study proposes that the hunger state exerts a detrimental effect on appropriate social decision- making by decreasing reaction time, increasing violation, and decreasing payoff equity in rule-observance behavior.
Abdelrahman Zkria,Fouad Abdel-Wahab,Yuki Katamune,Tsuyoshi Yoshitake 한국물리학회 2019 Current Applied Physics Vol.19 No.2
Ultrananocrystalline diamond/hydrogenated amorphous carbon composite films were deposited in the ambient of hydrogen by coaxial arc plasma deposition. The film compositions and chemical bonding structures were investigated by X-ray diffraction, X-ray photoemission and hydrogen forward scattering spectroscopies. The sp3 / (sp2 +sp3 ) ratio and hydrogen content in the film were estimated to be 64% and 35 at.%, respectively. The optical parameters and the optical dispersion profile were determined by using a variable angle spectroscopic ellipsometer at 55°, 65° and 75° angle of incidence in the photon energy range of 0.9–5 eV. Combinations of multiple Gaussian, and Tauc-Lorentz or Cody-Lorentz dispersion functions are used to reproduce the experimental data. Results of ellipsometry showed a refractive index of approximately 2.05 (at 2eV) and optical band gap of 1.63 eV. The imaginary part of dielectric function exhibited a peak at 3.8 eV, which has assigned to π-π* electron transitions. Furthermore, Electron spin resonance measurements implied the existence of dangling bonds, which might have a partial contribution to the optical absorption properties of the deposited films. A correlation between optical parameters and structural profile of the deposited films is discussed.
Induction of P3NS1 Myeloma Cell Death and Cell Cycle Arrest by Simvastatin and/or γ-Radiation
Abdelrahman, Ibrahim Y,Helwa, Reham,Elkashef, Hausein,Hassan, Nagwa HA Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.16
The present study was conducted to investigate the effect of ${\gamma}$-radiation alone or combined with a cytotoxic drug, simvastatin, on viability and cell cycling of a myeloma cell line. P3NS1 myeloma cells were treated with the selected dose of simvastatin ($0.1{\mu}M/l$) 24 hours prior to ${\gamma}$-irradiation (0.25, 0.5 and 1Gy). The cell viability, induction of apoptosis, cell death, cell cycling, generation of ROS, and expression of P53, Bax, Bcl2, caspase3, PARP1 and Fas genes were estimated. The results indicated that simvastatin ($0.1{\mu}M/l$) treatment for 24 hours prior to ${\gamma}$-irradiation increased cell death to 37.5% as compared to 4.81% by radiation (0.5Gy) alone. It was found that simvastatin treatment before irradiation caused arrest of cells in G0/G1 and G2/M phases as assessed using flow cytometry. Interestingly, simvastatin treatment of P3NS1 cells increased the intracellular ROS production and decreased antioxidant enzyme activity with increased P53, Bax and Caspase3 gene expression while that of Bcl2 was decreased. Consequently, our results indicated that pre-treatment with simvastatin increased radio sensitivity of myeloma tumor cells in addition to apoptotic effects through an intrinsic mitochondrial pathway.
Abdelrahman, Mohammad,Sang-Young Park IEEE 2011 IEEE transactions on aerospace and electronic syst Vol.47 No.2
<P>A generalized algorithm for spacecraft three-axis attitude and rate estimation is presented. The filter concept presented here is quite general and applicable to a wide range of sensor systems. The structure of the filter is built using spacecraft nonlinear dynamics in the presence of momentum exchange devices. Then quaternion kinematics are augmented with spacecraft dynamics to represent the filter process dynamics. Magnetometer measurements and their corresponding time derivatives are utilized to represent the filter measurement model. The filter is designed to suit spacecraft in low-Earth orbits, so the aerodynamic drag in addition to spacecraft magnetic residuals are included as disturbance torques to the process dynamics. To test the filter EgyptSat-1 is used as a real test case where a magnetometer and fiber-optic gyros are used for attitude and rate determination. A Monte-Carlo simulation is then applied to study the performance of the proposed filter with initial attitude and angular velocity sampled from a uniform distribution, each axis respectively. The filter shows the capability of estimating the attitude within 5 deg and rate on the order of 0.03 deg/s in each axis.</P>