共查询到20条相似文献,搜索用时 15 毫秒
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R. Fouad Ibrahim A. Shaaban Tarik E. Ali Mohammed A. Assiri S. S. Shenouda 《RSC advances》2021,11(60):37726
New and stable coordinated compounds have been isolated in a good yield. The chelates have been prepared by mixing Co(ii), Ni(ii), Cu(ii), and Cd(ii) metal ions with (1E)-1-((6-methyl-4-oxo-4H-chromen-3-yl)methylene)thiocarbonohydrazide (MCMT) in 2 : 1 stoichiometry (MCMT : M2+). Various techniques, including elemental microanalyses, molar conductance, thermal studies, FT-IR, 1H-NMR, UV-Vis, and XRD spectral analyses, magnetic moment measurements, and electrical conductivity, were applied for the structural and spectroscopic elucidation of the coordinating compounds. Further, computational studies using the DFT-B3LYP method were reported for MCMT and its metal complexes. MCMT behaves as a neutral NS bidentate moiety that forms octahedral complexes with general formula [M(MCMT)2Cl(OH2)]Cl·XH2O (M = Cu2+; (X = ½), Ni2+, Co2+; (X = 1)); [Cd(MCMT)2Cl2]·½H2O. There is good confirmation between experimental infrared spectral data and theoretical DFT-B3LYP computational outcomes where MCMT acts as a five-membered chelate bonded to the metal ion through azomethine nitrogen and thiocarbonyl sulphur donors. The thermal analysis is studied to confirm the elucidated structure of the complexes. Also, the kinetic and thermodynamic parameters of the thermal decomposition steps were evaluated. The measured optical band gap values of the prepared compounds exhibited semiconducting nature. AC conductivity and dielectric properties of the ligand and its complexes were examined, which showed that Cu(ii) complex has the highest dielectric constant referring to its high polarization and storage ability.New and stable coordinated compounds have been isolated in a good yield. 相似文献
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D Porche 《The Journal of the Association of Nurses in AIDS Care》2001,12(6):88-90
Treatment review is intended to inform and update nurses about treatments relevant to HIV/AIDS. Product information presented in this column does not imply endorsement by the Association of Nurses in Aids Care. 相似文献
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Giardia, Entamoeba, and Trichomonas Enzymes Activate Metronidazole (Nitroreductases) and Inactivate Metronidazole (Nitroimidazole Reductases)
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Dibyarupa Pal Sulagna Banerjee Jike Cui Aaron Schwartz Sudip K. Ghosh John Samuelson 《Antimicrobial agents and chemotherapy》2009,53(2):458-464
Infections with Giardia lamblia, Entamoeba histolytica, and Trichomonas vaginalis, which cause diarrhea, dysentery, and vaginitis, respectively, are each treated with metronidazole. Here we show that Giardia, Entamoeba, and Trichomonas have oxygen-insensitive nitroreductase (ntr) genes which are homologous to those genes that have nonsense mutations in metronidazole-resistant Helicobacter pylori isolates. Entamoeba and Trichomonas also have nim genes which are homologous to those genes expressed in metronidazole-resistant Bacteroides fragilis isolates. Recombinant Giardia, Entamoeba, and Trichomonas nitroreductases used NADH rather than the NADPH used by Helicobacter, and two recombinant Entamoeba nitroreductases increased the metronidazole sensitivity of transformed Escherichia coli strains. Conversely, the recombinant nitroimidazole reductases (NIMs) of Entamoeba and Trichmonas conferred very strong metronidazole resistance to transformed bacteria. The Ehntr1 gene of the genome project HM-1:IMSS strain of Entamoeba histolytica had a nonsense mutation, and the same nonsense mutation was present in 3 of 22 clinical isolates of Entamoeba. While ntr and nim mRNAs were variably expressed by cultured Entamoeba and Trichomonas isolates, there was no relationship to metronidazole sensitivity. We conclude that microaerophilic protists have bacterium-like enzymes capable of activating metronidazole (nitroreductases) and inactivating metronidazole (NIMs). While Entamoeba and Trichomonas displayed some of the changes (nonsense mutations and gene overexpression) associated with metronidazole resistance in bacteria, these changes did not confer metronidazole resistance to the microaerophilic protists examined here. 相似文献
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M A Alpert 《Southern medical journal》1999,92(9):858-865
Ample clinical and epidemiologic evidence exists to implicate homocyst(e)ine as a risk factor for atherosclerotic vascular disease and thrombosis. The precise mechanisms by which this occurs are uncertain but probably involve injury to endothelium, impairment of endothelial function, lipid peroxidation, oxidation of low-density lipoprotein, and creation of a prothrombotic environment in areas of endothelial injury. Plasma homocyst(e)ine concentration (PHC) can be effectively reduced with oral administration of folic acid. Whether vitamins B6 and B12 are also required in the absence of vitamin deficiency remains uncertain. Studies currently in progress may help to determine whether reduction of PHC will translate into a decrease in clinical vascular events. 相似文献
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《The Medical letter on drugs and therapeutics》2005,47(1200):5-7
Alprazolam, a widely prescribed benzodiazepine, is effective for treatment of anxiety and panic disorder but sedation, withdrawal symptoms and abuse are common. SSRIs are also effective and safer. Cognitive-behavioral therapy is probably more effective in the long term. 相似文献
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GENETIC CONTROL OF THE IMMUNE RESPONSE : In Vitro Stimulation of Lymphocytes by (T,G)-A--L, (H,G)-A--L, and (Phe,G)-A--L 总被引:5,自引:5,他引:5
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In vitro antigen-induced tritiated thymidine uptake has been used to study the response of sensitized lymphocytes to (T,G)-A--L, (H,G)-A--L, and (Phe,G)-A--L in responder and nonresponder strains of mice. The reaction is T-cell and macrophage dependent. Highly purified T cells (91% Thy 1.2 positive) are also responsive, suggesting that this in vitro lymphocyte transformation system is not B-cell dependent. Lymphocytes from high and low responder mice stimulated in vitro react as responders and nonresponders in a pattern identical to that seen with in vivo immunization. Stimulation occurs only if soluble antigen is added at physiological temperatures; antigen exposure at 4°C followed by washing and incubation at 37°C fails to induce lymphocyte transformation. Stimulation is specific for the immunizing antigen and does not exhibit the serologic cross-reactivity which is characteristic of these three antigens and their respective antisera. The reaction can be inhibited by anti-H-2 sera but not by anti-immunoglobulin sera. The anti-immunoglobulin sera did, however, inhibit lipopolysaccharide or pokeweed mitogen stimulation. These results suggest that the Ir-1A gene(s) are expressed in T cells, and that there are fundamental physiologic differences between T- and B-cell antigen recognition. 相似文献
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Khuloud A. Alibrahim Foziah A. Al-Saif M. T. Alghamdi M. S. El-Shahawi Y.
M. Moustafa Moamen S. Refat 《RSC advances》2018,8(40):22515
Three new solid complexes of pipemidic acid (Pip–H) with Ru3+, Pt4+ and Ir3+ were synthesized and characterized. Pipemidic acid acts as a uni-dentate chelator through the nitrogen atom of the –NH piperazyl ring. The spectroscopic data revealed that the general formulas of Pip–H complexes are [M(L)n(Cl)x]·yH2O ((1) M = Ru3+, L: Pip–H, n = 3, x = 3, y = 6; (2) M = Pt4+, L: Pip–NH4, n = 2, x = 4, y = 0 and (3) M = Ir3+, L: Pip–H, n = 3, x = 3, y = 6). The number of water molecules with their locations inside or outside the coordination sphere were assigned via thermal analyses (TG, DTG). The DTG curves refer to 2–3 thermal decomposition steps where the first decomposition step at a lower temperature corresponds to the loss of uncoordinated water molecules followed by the decomposition of Pip–H molecules at higher temperatures. Thermodynamic parameters (E*, ΔS*, ΔH* and ΔG*) were calculated from the TG curves using Coats–Redfern and Horowitz–Metzeger non-isothermal models. X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques were carefully used to assign properly the particle sizes of the prepared Pip–H complexes. The biological enhancement of Pip–H complexes rather than free chelate were assessed in vitro against four kinds of bacteria G(+) (Staphylococcus epidermidis and Staphylococcus aureus) and G(−) (Klebsiella and Escherichia coli) as well as against the human breast cancer (MCF-7) tumor cell line.Three new solid complexes of pipemidic acid (Pip–H) with Ru3+, Pt4+ and Ir3+ were synthesized and characterized. Pipemidic acid acts as a uni-dentate chelator through the nitrogen atom of the –NH piperazyl ring. 相似文献
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Because of the involvement of proteinases in the activation mechanism of thrombocytes and granulocytes, the effect of proteinase inhibitors was tested. To document cell activation we used thrombocyte and granulocyte aggregation. Chemiluminescence and superoxide production were used as parameters for the release of activated oxygen compounds, and lysozyme as a marker of lysosomal enzyme release. FOY and aprotinin inhibited all but not arachidonic acid thrombocyte aggregation. Only aprotinin diminished granulocyte responses to various stimuli, while FOY was without effect at concentration less than 100 microM. 相似文献