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Search Results: 1 - 10 of 4343 matches for " Omar Janneh "
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Interactions of Tenofovir, Lamivudine, Abacavir and Didanosine in Primary Human Cells
Omar Janneh,Saye H. Khoo
Pharmaceutics , 2011, DOI: 10.3390/pharmaceutics3020326
Abstract: Certain triple nucleoside/tide reverse transcriptase inhibitor (NRTI) regimens containing tenofovir (TDF) have been associated with rapid early treatment failure. The mechanism is unknown, but may be at the level of drug transport. We measured the lipophilicity of the drugs [ 3H]-lamivudine (3TC), -didanosine (ddI), -TDF and -ABC. Peripheral blood mononuclear cells (PBMCs) were used to evaluate drug–drug interactions at the level of drug transport. PBMCs were measured for the expression of P-glycoprotein (P-gp), multidrug resistance-associated protein-1 (MRP-1) and breast cancer resistance protein (BCRP) by flow cytometry. The rank order of the lipophilicity of the drugs were ABC>>>3TC3ddI>TDF. The accumulation of [ 3H]-3TC, -ddI and -TDF were temperature sensitive (suggesting facilitated transport), in contrast to [ 3H]-ABC. ABC reduced the accumulation of [ 3H]-3TC, and cell fractionation experiments suggested this was mainly in membrane-bound [ 3H]-3TC. ABC/TDF and ABC/ddI increased the accumulation of [ 3H]-3TC and 3TC/TDF also increased the accumulation of [ 3H]-TDF. In contrast, none of the NRTI/NtRTI incubations (alone or in combination) altered the accumulation of [ 3H]-ABC and -ddI. PBMC expression of P-gp, MRP1 and BCRP were detected, but none correlated with the accumulation of the drugs. The high failure rates seen with TDF, ABC and 3TC are not fully explained by an interaction at transporter level.
Glutathione transferase-P1-1 binding with naturally occurring ligands: assessment by docking simulations  [PDF]
Anupam J. Das, Sreeda Chalil, Poonam Nigam, Pamela Magee, Omar Janneh, Richard Owusu-Apenten
Journal of Biophysical Chemistry (JBPC) , 2011, DOI: 10.4236/jbpc.2011.24046
Abstract: Glutathione transferase-P1-1 (hGSTP1-1), which is associated with acquired drug resistance in some tumour cells, requires two identical subunits for full activity. Naturally occurring inhibitors for GSTP1-1 quaternary structure could be interesting therapeutic agents. The aim of this study was to investigate potential binding sites for hGSTP1-1 interaction with ligands many of which occur naturally. Simulations were performed with commercial docking software and with GST monomer or dimer as template. Docking results using hGSTP1-1 dimer showed one binding site for most of the ligands tested. Lycopene, glutathione, ellagic acid, ethacrynic acid, quercetin, caffeic acid, ferulic acid, porphyrin, curcumin, cinnamic acid, and also α-tocopherol bound at the enzyme dimer subunit-subunit interface. In contrast, investigations using hGSTP1-1 monomer revealed three additional sites for ligand binding. In conclusion, the docking simulations suggest that the enzyme subunit interface may be important for hGSTP1-1 interactions with ligands. These findings may provide valuable insights for further research to identify naturally occurring therapeutic agents.
Evaluation of antimalarial, free-radical-scavenging and insecticidal activities of Artemisia scoparia and A. Spicigera, Asteraceae
Fariba H. Afshar,Abbas Delazar,Omar Janneh,Hossein Nazemiyeh
Revista Brasileira de Farmacognosia , 2011,
Abstract: Artemisia species (Asteraceae), widespread throughout the world, are a group of important medicinal plants. The extracts of two medicinal plants of this genus, Artemisia scoparia Waldst. & Kit. and A. spicigera C. Koch, were evaluated for potential antimalarial, free-radical-scavenging and insecticidal properties, using the heme biocrystallisation and inhibition assay, the DPPH assay and the contact toxicity bioassay using the pest Tribolium castaneum, respectively. The methanol extracts of both species showed strong free-radical-scavenging activity and the RC50 values were 0.0317 and 0.0458 mg/mL, respectively, for A. scoparia and A. spicigera. The dichloromethane extracts of both species displayed a moderate level of potential antimalarial activity providing IC50 at 0.778 and 0.999 mg/mL for A. scoparia and A. spicigera, respectively. Both species of Artemisia showed insecticidal properties. However, A. spicigera was more effective than A. scoparia.
Attenuation of Doxorubicin-Induced Cardiotoxicity by mdivi-1: A Mitochondrial Division/Mitophagy Inhibitor
Mayel Gharanei, Afthab Hussain, Omar Janneh, Helen Maddock
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0077713
Abstract: Doxorubicin is one of the most effective anti-cancer agents. However, its use is associated with adverse cardiac effects, including cardiomyopathy and progressive heart failure. Given the multiple beneficial effects of the mitochondrial division inhibitor (mdivi-1) in a variety of pathological conditions including heart failure and ischaemia and reperfusion injury, we investigated the effects of mdivi-1 on doxorubicin-induced cardiac dysfunction in na?ve and stressed conditions using Langendorff perfused heart models and a model of oxidative stress was used to assess the effects of drug treatments on the mitochondrial depolarisation and hypercontracture of cardiac myocytes. Western blot analysis was used to measure the levels of p-Akt and p-Erk 1/2 and flow cytometry analysis was used to measure the levels p-Drp1 and p-p53 upon drug treatment. The HL60 leukaemia cell line was used to evaluate the effects of pharmacological inhibition of mitochondrial division on the cytotoxicity of doxorubicin in a cancer cell line. Doxorubicin caused a significant impairment of cardiac function and increased the infarct size to risk ratio in both na?ve conditions and during ischaemia/reperfusion injury. Interestingly, co-treatment of doxorubicin with mdivi-1 attenuated these detrimental effects of doxorubicin. Doxorubicin also caused a reduction in the time taken to depolarisation and hypercontracture of cardiac myocytes, which were reversed with mdivi-1. Finally, doxorubicin caused a significant elevation in the levels of signalling proteins p-Akt, p-Erk 1/2, p-Drp1 and p-p53. Co-incubation of mdivi-1 with doxorubicin did not reduce the cytotoxicity of doxorubicin against HL-60 cells. These data suggest that the inhibition of mitochondrial fission protects the heart against doxorubicin-induced cardiac injury and identify mitochondrial fission as a new therapeutic target in ameliorating doxorubicin-induced cardiotoxicity without affecting its anti-cancer properties.
Composition, antioxidant and chemotherapeutic properties of the essential oils from two Origanum species growing in Pakistan
Hussain, Abdullah I.;Anwar, Farooq;Rasheed, Shazia;Nigam, Poonam S.;Janneh, Omar;Sarker, Satyajit D.;
Revista Brasileira de Farmacognosia , 2011, DOI: 10.1590/S0102-695X2011005000165
Abstract: the gc-ms analyses of origanum majorana l. (ome) and origanum vulgare l. (ove), lamiaceae, essential oils helped identification of 39 (96.4% of the total oils) and 43 (92.9% of the total oils) components, respectively. the major constituents of ome were terpinene-4-ol (20.9%), linalool (15.7%), linalyl-acetate (13.9%), limonene (13.4%) and α-terpineol (8.57%), whereas, thymol (21.6%), carvacrol (18.8%), o-cymene (13.5%) and α-terpineol (8.57%) were the main components of ove. in the disc diffusion and the resazurin microtitre assays, ome showed better antibacterial activity than ove with larger zones of inhibition (16.5-27.0 mm) and smaller mic (40.9-1250.3 μg/ml) against the tested bacterial strains. only ove displayed anti-heme biocrystallization activity with an ic50 at 0.04 mg/ml. in the dpph assay, ove showed better radical-scavenging activity than ome (ic50=65.5 versus 89.2 μg/ml) and both ome and ove inhibited lionleic acid oxidation. however, in the bleaching β-carotene assay, ove exhibited better antioxidant activity than ome. in the mtt assay, ome was more cytotoxic than ove against different cancer cell types, such as mcf-7, lncap and nih-3t3, with ic50s of 70.0, 85.3 and 300.5 μg/ml, respectively. overall, some components of ome and ove may have antiparasitic and chemotherapeutic activity.
Evaluation of antimalarial, free-radical-scavenging and insecticidal activities of Artemisia scoparia and A. Spicigera, Asteraceae
Afshar, Fariba H.;Delazar, Abbas;Janneh, Omar;Nazemiyeh, Hossein;Pasdaran, Ardalan;Nahar, Lutfun;Sarker, Satyajit D.;
Revista Brasileira de Farmacognosia , 2011, DOI: 10.1590/S0102-695X2011005000144
Abstract: artemisia species (asteraceae), widespread throughout the world, are a group of important medicinal plants. the extracts of two medicinal plants of this genus, artemisia scoparia waldst. & kit. and a. spicigera c. koch, were evaluated for potential antimalarial, free-radical-scavenging and insecticidal properties, using the heme biocrystallisation and inhibition assay, the dpph assay and the contact toxicity bioassay using the pest tribolium castaneum, respectively. the methanol extracts of both species showed strong free-radical-scavenging activity and the rc50 values were 0.0317 and 0.0458 mg/ml, respectively, for a. scoparia and a. spicigera. the dichloromethane extracts of both species displayed a moderate level of potential antimalarial activity providing ic50 at 0.778 and 0.999 mg/ml for a. scoparia and a. spicigera, respectively. both species of artemisia showed insecticidal properties. however, a. spicigera was more effective than a. scoparia.
Hard Decision-Based PWM for MIMO-OFDM Radar  [PDF]
Omar Daoud
Communications and Network (CN) , 2015, DOI: 10.4236/cn.2015.71004
Abstract: For the purpose of target localization, Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing (MIMO-OFDM) radar has been proposed. OFDM technique has been adopted in order to a simultaneous transmission and reception of a set of multiple narrowband orthogonal signals at orthogonal frequencies. Although multi-carrier systems such as OFDM support high data rate applications, they do not only require linear amplification but also they complicate the power amplifiers design and increase power consumption. This is because of high peak-to-average power ratio (PAPR). In this work, a new proposition has been made based on the Pulse Width Modulation (PWM) to enhance the MIMO-OFDM radar systems’ performance. In order to check the proposed systems performance and its validity, a numerical analysis and a MATLAB simulation have been conducted. Nevertheless of the system characteristics and under same bandwidth occupancy and system’s specifications, the simulation results show that this work can reduce the PAPR values clearly and show capable results over the ones in the literature.
Numerical Investigation of Phase and Group Propagation of Time-Domain Signals in a Novel Band-Reject Metamaterial Ring Hybrid  [PDF]
Omar Siddiqui
Journal of Computer and Communications (JCC) , 2015, DOI: 10.4236/jcc.2015.36002
Abstract: Phase and group propagation in metamaterial-based microwave components has always been intellectually challenging for students and engineers new to the area of periodic structures and metamaterials. This paper aims in tackling this important topic by studying the wave propagation in a metamaterial-based microwave device. Hence, the contribution of this paper is twofold. First, design of a novel metamaterial ring hybrid (or rate-race) is presented which has a large rejection band so that the second and third harmonics are effectively suppressed. Second, the electromagnetic phase and the group propagation in the ring hybrid are investigated by numerically exciting the input ports with band-limited Gaussian pulses and then finding their responses at various locations in the device.
Investigation of the Quaternion Dynamical System  [PDF]
Yasmin Omar
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.51014
Abstract: The quaternion Mandelbrot set is one of the most important sets in mathematics. In this paper we first give some properties of the quaternion algebra. Then, we introduce the quternion dynamical system. We are concerned with analytical and numerical investigation of the quaternion dynamical system.
Pattern-Oriented Approach for Enterprise Architecture: TOGAF Framework  [PDF]
Mohamed Taleb, Omar Cherkaoui
Journal of Software Engineering and Applications (JSEA) , 2012, DOI: 10.4236/jsea.2012.51008
Abstract: Design pattern suggests that developers must be able to reuse proven solutions emerging from the best design practices to solve common design problems while composing patterns to create reusable designs that can be mapped to different types of enterprise frameworks and architectures such as The Open Group Architecture Framework (TOGAF). Without this, business analysts, designers and developers are not properly applying design solutions or take full benefit of the power of patterns as reuse blocks, resulting in poor performance, poor scalability, and poor usability. Furthermore, these professionals may “reinvent the wheel” when attempting to implement the same design for different types of architectures of TOGAF framework. In this paper, we introduce different categories of design patterns as a vehicle for capturing and reusing good analyses, designs and implementation applied to TOGAF framework while detailing a motivating exemplar on how design patterns can be composed to create generic types of architectures of TOGAF framework. Then, we discuss why patterns are a suitable for developing and documenting various architectures including enterprise architectures as TOGAF.
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