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1.
Plants (Basel) ; 11(22)2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36432849

RESUMO

Cnidium officinale is a medicinal plant cultivated for its rhizomes, which are used in Chinese, Japanese, and Korean traditional medicine. This medicinal crop is highly susceptible to heat stress and cannot be cultivated in regions of higher temperatures. In the present study, ten clones from Korea (clones 1, 2, 5, 6, 8, 11, 14, 15, 22, and 26) were evaluated for their heat tolerance in vitro at 25, 30, 32.5, and 35 °C, and growth characteristics including plant height, the number of leaves and roots were evaluated. The initial experiment was conducted to find the threshold level for significant damage to the plant, while the second experiment was to screen the germplasm to select heat-tolerant clones. Most of the clones were sensitive to heat stress (clones 1, 2, 8, 11, 14, 15, 22, and 26), and few clones (clones 5 and 6) could perform well at an elevated temperature of 32.5 °C. Molecular analysis of the expression of heat-responsive genes, including heat shock protein (CoHSP), catalase (CoCAT), and cystine protease (CoCP), was performed by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) carried out with heat-tolerant and heat-sensitive clones. Two of the heat-tolerant clones (clones 5 and 6) showed significant expression of CoHSP and CoCAT genes at elevated temperature treatment. These clones can be used for further evaluation and cultivation.

2.
Stem Cell Res ; 65: 102965, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36403547

RESUMO

A human induced pluripotent stem cell (hiPSC) line, KSCBi017-A, was generated from a 50-year-old male individual using non-integrating episomal vectors expressing reprogramming factors. The generated hiPSCs were integration-free, expressed pluripotency markers, exhibited the potential for differentiation into three germ layers in vivo, and maintained the normal karyotype. This cell line can be used as a control for a disease model and is available from Korea National Stem Cell Bank.


Assuntos
Células-Tronco Pluripotentes Induzidas , Humanos , Masculino , Pessoa de Meia-Idade , Leucócitos Mononucleares
3.
Genes (Basel) ; 13(10)2022 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-36292700

RESUMO

Cnidium officinale is a valuable medicinal plant cultivated in Asia for its rhizomes. This study reports the in vitro regeneration of Cnidium officinale plants and the induction of rhizomes from microshoots. The rhizomatous buds of Cnidium officinale induced multiple shoots on Murashige and Skoog (MS) medium supplemented with 0.5 mg L-1 BA, which led to the regeneration of plants within four weeks of culture. After four weeks of culture, the plants were assessed for fresh weight, the number of leaves, the number of roots, and the length of roots to compare the performance of the different clones. The clones with good growth characteristics were selected with the aid of a flow cytometric analysis of 2C nuclear DNA content. The plants bearing high DNA values showed better growth characteristics. Various factors, namely, sucrose concentration (30, 50, 70, and 90 g L-1), ABA (0, 0.5, 1.0, and 2.0 mg L-1), the synergistic effects of BA (1.0 mg L-1) + NAA (0.5 mg L-1) and BA (1.0 mg L-1) + NAA (0.5 mg L-1) + ABA (1.0 mg L-1) with or without activated charcoal (1 g L-1), and light and dark incubation were tested on rhizome formation from microshoots. The results of the above experiments suggest that MS medium supplemented with 50 g L-1 sucrose, 1.0 mg L-1 ABA, and 1 g L-1 AC is good for the induction of rhizomes from the shoots of Cnidium officinale. Plantlets with rhizomes were successfully transferred to pots, and they showed 100% survival.


Assuntos
Cnidium , Reguladores de Crescimento de Plantas , Brotos de Planta/genética , Reguladores de Crescimento de Plantas/farmacologia , Carvão Vegetal/farmacologia , Células Clonais , Sacarose/farmacologia
4.
Stem Cell Res ; 63: 102841, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35700632

RESUMO

A human induced pluripotent cell (hiPSC) line, KSCBi012-A, was generated from a 40-year-old male individual using non-integrating episomal vectors expressing reprogramming factors. The generated hiPSCs were integration-free, expressed pluripotency markers, exhibited the potential for differentiation into three germ layers in vivo, and maintained the normal karyotype. This cell line can be used as a control for a disease model and is available from Korea National Stem Cell Bank.


Assuntos
Células-Tronco Pluripotentes Induzidas , Adulto , Diferenciação Celular , Linhagem Celular , Reprogramação Celular , Células Epiteliais , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Masculino , Plasmídeos
5.
Environ Res ; 194: 110657, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33388287

RESUMO

Nickel has been extensively used as a high work function metal because of its abundance, low cost, relatively non-toxic nature, and environmentally benign characteristics. However, it has rarely been extended in a form of immobilized composite, which is a practical strategy applicable for photocatalytic antimicrobial activities. In this study, a composite of nickel and TiO2 (Ni/TiO2) was prepared using a photodeposition method, and its antibacterial properties were investigated using Escherichia coli (E. coli). To optimize Ni/TiO2 synthesis, the effect of various photodeposition conditions on antibacterial performance were investigated, such as the light irradiation time, metal content, TiO2 crystalline structure, and presence or absence of electron donors (i.e., methanol). The optimized 2 wt% Ni/TiO2 exhibited an antibacterial efficiency of 3.74 log within 7 min, which is more than 10-fold higher than that of pristine TiO2 (2.54 log). Based on this optimized weight ratio, Ni/TiO2 was immobilized on a steel mesh using an electrospray/thermal compression method, and its antibacterial performance was further assessed against E. coli, MS2 bacteriophage virus (MS2 phage), and a common pulmonary pathogen (Legionella thermalis, L. thermalis). Within 70 min, all target microorganisms achieved an inactivation that exceeded 4 log. Furthermore, the long-term stability and sustainable usability of the Ni/TiO2 mesh were confirmed by performing more than 50 antibacterial evaluation cycles using E. coli. The results of this study facilitate the successful utilization of immobilized Ni/TiO2 mesh in water disinfection applications.


Assuntos
Escherichia coli , Nanocompostos , Antibacterianos/farmacologia , Catálise , Legionella , Levivirus , Titânio
6.
Sci Total Environ ; 712: 136574, 2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32050388

RESUMO

Although zinc oxide nanorod (ZnO NR) arrays are a nanomaterial that offers efficient bactericidal activity, they have not been systematically evaluated to quantitatively investigate their disinfection mechanism under dark conditions. In this study, ZnO NR arrays of different lengths (0.5-4 µm) were uniformly grown via hydrothermal synthesis. The longer arrays exhibited higher Escherichia coli (E. coli) inactivation efficiency up to 94.2% even under darkness for 30 min. When the NR arrays were coated via Al2O3 atomic layer deposition, the inactivation efficiency was decreased to 56.4% because the generation of reactive oxygen species (ROS) and the leaching of Zn2+ ions were both hindered by the surficial coverage of defect sites. The morphological effect, i.e., the mechanical rupture of E. coli on the surface, contributed 56.4% of the bactericidal efficiency; chemical effects, i.e., ROS formation and zinc ion release, contributed the remaining 37.8% under dark conditions. The bactericidal effect of fabricated ZnO NR arrays was further validated in bottled and pond water spiked with E. coli, exhibiting 87.5% and 80.4% inactivation efficiencies, respectively, within 30 min. Understanding these antibacterial mechanisms is not only of significance for research in this and related fields but also beneficial for potential application in various fields, e.g., biomedical and antifouling areas.


Assuntos
Nanotubos , Antibacterianos , Escherichia coli , Zinco , Óxido de Zinco
7.
Sci Rep ; 9(1): 13697, 2019 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-31548584

RESUMO

To overcome the conventional limitation of TiO2 disinfection being ineffective under light-free conditions, TiO2 nanowire films (TNWs) were prepared and applied to bacterial disinfection under dark and UV illumination. TNW exhibited much higher antibacterial efficiencies against Escherichia coli (E. coli) under dark and UV illumination conditions compared to TiO2 nanoparticle film (TNP) which was almost inactive in the dark, highlighting the additional contribution of the physical interaction between bacterial membrane and NWs. Such a physical contact-based antibacterial activity was related to the NW geometry such as diameter, length, and density. The combined role of physical puncture and photocatalytic action in the mechanism underlying higher bactericidal effect of TNW was systematically examined by TEM, SEM, FTIR, XPS, and potassium ion release analyses. Moreover, TNW revealed antimicrobial activities in a broad spectrum of microorganisms including Staphylococcus aureus and MS2 bacteriophage, antibiofilm properties, and good material stability. Overall, we expect that the free-standing and antimicrobial TNW is a promising agent for water disinfection and biomedical applications in the dark and/or UV illumination.


Assuntos
Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Titânio/química , Raios Ultravioleta , Desinfecção/métodos
8.
Environ Sci Technol ; 53(5): 2679-2687, 2019 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-30698421

RESUMO

Bimetallic iron-copper nanoparticles (Fe/Cu-NPs) were synthesized by a single-pot surfactant-free method in aqueous solution [via the reduction of ferrous ion to zerovalent iron nanoparticles (Fe-NPs) and the subsequent copper-coating by metal ion exchange]. The produced Fe/Cu-NPs formed aggregates of spherical nanoparticles (approximately 30-70 nm) of Fe-Cu core-shell structures with 11 wt % copper content. The microbicidal effects of Fe/Cu-NPs were explored on Escherichia coli and MS2 coliphage, surrogates for bacterial and viral pathogens, respectively. Fe/Cu-NPs exhibited synergistically enhanced activity for the inactivation of E. coli and MS2, compared to single-metal nanoparticles (i.e., Fe-NPs and Cu-NPs). Various experiments (microbial inactivation tests under different conditions, fluorescence staining assays, experiments using ELISA and qRT-PCR, etc.) suggested that Fe/Cu-NPs inactivate E. coli and MS2 via dual microbicidal mechanisms. Two biocidal copper species [Cu(I) and Cu(III)] can be generated by different redox reactions of Fe/Cu-NPs. It is suggested that E. coli is strongly influenced by the cytotoxicity of Cu(I), while MS2 is inactivated mainly due to the oxidative damages of protein capsid and RNA by Cu(III).


Assuntos
Cobre , Nanopartículas Metálicas , Colífagos , Escherichia coli , Ferro
9.
J Hazard Mater ; 360: 62-70, 2018 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-30077039

RESUMO

An immobilized photocatalyst was prepared by thermally treating TiO2-coated steel mesh (TiO2-IS) in a laboratory hot-press with no binder. TiO2 coating was performed by electrospraying a 1 mg/mL methanol dispersion of Evonik P25 powder. The thermal treatment conditions at 350 °C, 100 Mpa, and 1 h were found to be the optimum conditions. Scanning electron microscopic images displayed a robust and adherent TiO2 layer on steel mesh. X-ray photoelectron spectroscopy and elemental mapping studies confirmed that the Fe3O4 interface formed during thermal treatment strongly bound the TiO2 on steel mesh. The XRD patterns of TiO2-IS indicated the preservation of crystalline structure of Evonik P25 (anatase and rutile mixture) and the existence of iron oxide interface. Under UVA irradiation, 10 µM of methylene blue was completely decolorized within 40 min using an immobilized photocatalyst with 2.120 mg of TiO2 per 2.5 × 5.0 cm2 and showed stable efficacy in 25 consecutive photocatalytic runs. Furthermore, this sample degraded the organic micropollutants (e.g., pharmaceuticals) such as carbamazepine, ranitidine, acetaminophen, and trimethoprim at the rates of 0.041, 0.165, 0.089, and 0.079 min-1, respectively. Under UVA irradiation, it exhibited high photocatalytic disinfection activity for Escherichia coli and MS2 coliphage.

10.
Water Res ; 110: 83-90, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-27998786

RESUMO

Combinations of Cu(II) with hydroxylamine (HA) and hydrogen peroxide (H2O2) (i.e., Cu(II)/HA, Cu(II)/H2O2, and Cu(II)/HA/H2O2 systems) were investigated for the control of P. aeruginosa biofilms on reverse osmosis (RO) membranes. These Cu(II)-based disinfection systems effectively inactivated P. aeruginosa cells, exhibiting different behaviors depending on the state of bacterial cells (planktonic or biofilm) and the condition of biofilm growth and treatment (normal or pressurized condition). The Cu(II)/HA and Cu(II)/HA/H2O2 systems were the most effective reagents for the inactivation of planktonic cells. However, these systems were not effective in inactivating cells in biofilms on the RO membranes possibly due to the interactions of Cu(I) with extracellular polymeric substances (EPS), where biofilms were grown and treated in center for disease control (CDC) reactors. Different from the results using CDC reactors, in a pressurized cross-flow RO filtration unit, the Cu(II)/HA/H2O2 treatment significantly inactivated biofilm cells formed on the RO membranes, successfully recovering the permeate flux reduced by the biofouling. The pretreatment of feed solutions by Cu(II)/HA and Cu(II)/HA/H2O2 systems (applied before the biofilm formation) effectively mitigated the permeate flux decline by preventing the biofilm growth on the RO membranes.


Assuntos
Biofilmes , Peróxido de Hidrogênio , Incrustação Biológica/prevenção & controle , Hidroxilamina , Hidroxilaminas , Membranas Artificiais , Osmose , Purificação da Água
12.
Environ Sci Technol ; 50(15): 8231-8, 2016 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-27387011

RESUMO

This study reports that the combination of Cu(II) with hydroxylamine (HA) (referred to herein as Cu(II)/HA system) in situ generates H2O2 by reducing dissolved oxygen, subsequently producing reactive oxidants through the reaction of Cu(I) with H2O2. The external supply of H2O2 to the Cu(II)/HA system (i.e., the Cu(II)/H2O2/HA system) was found to further enhance the production of reactive oxidants. Both the Cu(II)/HA and Cu(II)/H2O2/HA systems effectively oxidized benzoate (BA) at pH between 4 and 8, yielding a hydroxylated product, p-hydroxybenzoate (pHBA). The addition of a radical scavenger, tert-butyl alcohol, inhibited the BA oxidation in both systems. However, electron paramagnetic resonance (EPR) spectroscopy analysis indicated that (•)OH was not produced under either acidic or neutral pH conditions, suggesting that the alternative oxidant, cupryl ion (Cu(III)), is likely a dominant oxidant.


Assuntos
Cobre/química , Peróxido de Hidrogênio/química , Espectroscopia de Ressonância de Spin Eletrônica , Hidroxilamina , Hidroxilaminas , Oxirredução , Oxigênio
13.
Environ Sci Technol ; 50(13): 7106-15, 2016 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-27268462

RESUMO

Oxidation by persulfates at elevated temperatures (thermally activated persulfates) disintegrates bacterial cells and extracellular polymeric substances (EPS) composing waste-activated sludge (WAS), facilitating the subsequent sludge dewatering. The WAS disintegration process by thermally activated persulfates exhibited different behaviors depending on the types of persulfates employed, that is, peroxymonosulfate (PMS) versus peroxydisulfate (PDS). The decomposition of PMS in WAS proceeded via a two-phase reaction, an instantaneous decomposition by the direct reaction with the WAS components followed by a gradual thermal decay. During the PMS treatment, the WAS filterability (measured by capillary suction time) increased in the initial stage but rapidly stagnated and even decreased as the reaction proceeded. In contrast, the decomposition of PDS exhibited pseudo first-order decay during the entire reaction, resulting in the greater and steadier increase in the WAS filterability compared to the case of PMS. The treatment by PMS produced a high portion of true colloidal solids (<1 µm) and eluted soluble and bound EPS, which is detrimental to the WAS filterability. However, the observations regarding the dissolved organic carbon, ammonium ions, and volatile suspended solids collectively indicated that the treatment by PMS more effectively disintegrated WAS compared to PDS, leading to higher weight (or volume) reduction by postcentrifugation.


Assuntos
Oxirredução , Esgotos/microbiologia , Polímeros , Eliminação de Resíduos Líquidos
14.
Environ Sci Technol ; 49(24): 14416-23, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26575593

RESUMO

The inactivation of Escherichia coli and MS2 coliphage by Cu(II) is found to be significantly enhanced in the presence of hydroxylamine (HA). The addition of a small amount of HA (i.e., 5-20 µM) increased the inactivation efficacies of E. coli and MS2 coliphage by 5- to 100-fold, depending on the conditions. Dual effects were anticipated to enhance the biocidal activity of Cu(II) by the addition of HA, viz. (i) the accelerated reduction of Cu(II) into Cu(I) (a stronger biocide) and (ii) the production of reactive oxidants from the reaction of Cu(I) with dissolved oxygen (evidenced by the oxidative transformation of methanol into formaldehyde). Deaeration enhanced the inactivation of E. coli but slightly decreased the inactivation efficacy of MS2 coliphage. The addition of 10 µM hydrogen peroxide (H2O2) greatly enhanced the MS2 inactivation, whereas the same concentration of H2O2 did not significantly affect the inactivation efficacy of E. coli Observations collectively indicate that different biocidal actions lead to the inactivation of E. coli and MS2 coliphage. The toxicity of Cu(I) is dominantly responsible for the E. coli inactivation. However, for the MS2 coliphage inactivation, the oxidative damage induced by reactive oxidants is as important as the effect of Cu(I).


Assuntos
Cobre/farmacologia , Desinfetantes/farmacologia , Escherichia coli/efeitos dos fármacos , Hidroxilamina/farmacologia , Levivirus/efeitos dos fármacos , Cobre/química , Relação Dose-Resposta a Droga , Peróxido de Hidrogênio/farmacologia , Oxidantes/química , Oxidantes/farmacologia , Oxirredução , Oxigênio/química , Microbiologia da Água
15.
Water Res ; 86: 66-73, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26093796

RESUMO

The production of reactive oxidants from nanoparticulate zero-valent iron (nZVI) and ferrous ion (Fe(II)) in the presence of oxygen was greatly enhanced by the addition of tetrapolyphosphate (TPP) as an iron-chelating agent. Compared to other ligands, TPP exhibited superior activity in improving the oxidant yields. The nZVI/TPP/O2 and the Fe(II)/TPP/O2 systems showed similar oxidant yields with respect to the iron consumed, indicating that nZVI only serves as a source of Fe(II). The degradation efficacies of selected organic compounds were also similar in the two systems. It appeared that both hydroxyl radical (OH) and ferryl ion (Fe(IV)) are produced, and OH dominates at acidic pH. However, at pH > 6, little occurrence of hydroxylated oxidation products suggests that Fe(IV) is a dominant oxidant. The degradation rates of selected organic compounds by the Fe(II)/TPP/O2 system had two optimum points at pH 6 and 9, and these pH-dependent trends are likely attributed to the speciation of Fe(IV) with different reactivities.


Assuntos
Ferro/química , Nanopartículas Metálicas/química , Oxidantes/química , Oxigênio/química , Polifosfatos/química , Quelantes/química , Radical Hidroxila/química , Ligantes , Oxirredução
16.
J Korean Med Sci ; 30(4): 371-7, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25829803

RESUMO

Children have dynamic process of maturation and substantial changes in growth and development which eventually make the drug safety profiles different from adults. Medication errors (MEs) in pediatrics are reported to occur three times more likely than adults. The aims of this study were to identify the characteristics of pediatric MEs in Korea at national level and help raise awareness of risks from the MEs in pediatrics. We conducted a descriptive analysis with the pediatric ME reports in Korea Adverse Event Reporting System (KAERS) database from 1989 to 2012 and 208 ME reports in pediatrics were found. Based on KAERS database, the proportion of reported pediatric ME in adverse drug event (ADE) reports was 2.73 times (95% CI, 2.35-3.17) higher than that of adult ME. In 208 ME reports, we found a total of 236 ME-related terms within 19 types of MEs. The most common type of MEs was "accidental overdose" (n=58, 24.6%), followed by "drug maladministration" (n=50, 21.2%) and "medication error" (n=41, 17.4%). After the narratives of ME reports were reviewed, we noticed that most of them did no harm to patients, but some cases were needed for medical treatment. Our data suggest that MEs in pediatrics are not negligible in Korea. We expect that this study would increase the awareness of the problem in pediatric MEs and induce the need for further development of an effective national ME preventing system in Korea.


Assuntos
Sistemas de Notificação de Reações Adversas a Medicamentos , Bases de Dados Factuais , Erros de Medicação/estatística & dados numéricos , Adulto , Criança , Humanos , República da Coreia/epidemiologia , Fatores de Tempo
17.
Korean J Parasitol ; 52(5): 537-40, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25352704

RESUMO

We present a case of ocular toxocariasis treated successfully with oral albendazole in combination with steroids. A 26-year-old male visited the authors' clinic with the chief complaint of flying flies in his right eye. The fundus photograph showed a whitish epiretinal scar, and the fluorescein angiography revealed a hypofluorescein lesion of the scar and late leakage at the margin. An elevated retinal surface and posterior acoustic shadowing of the scar were observed in the optical coherence tomography, and Toxocara IgG was positive. The patient was diagnosed with toxocariasis, and the condition was treated with albendazole (400 mg twice a day) for a month and oral triamcinolone (16 mg for 2 weeks, once a day, and then 8 mg for 1 week, once a day) from day 13 of the albendazole treatment. The lesions decreased after the treatment. Based on this study, oral albendazole combined with steroids can be a simple and effective regimen for treating ocular toxocariasis.


Assuntos
Albendazol/uso terapêutico , Oftalmopatias/tratamento farmacológico , Oftalmopatias/parasitologia , Toxocaríase/tratamento farmacológico , Triancinolona/uso terapêutico , Adulto , Albendazol/administração & dosagem , Anti-Helmínticos/administração & dosagem , Anti-Helmínticos/uso terapêutico , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/uso terapêutico , Humanos , Masculino , Triancinolona/administração & dosagem
18.
Korean J Ophthalmol ; 28(5): 386-92, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25276080

RESUMO

PURPOSE: To investigate which spectral domain optical coherence tomography (SD-OCT) findings predict visual outcome after anti-vascular endothelial growth factor (VEGF) treatment in neovascular age-related macular degeneration (NV-AMD). METHODS: We reviewed the medical records of patients with treatment-naïve NV-AMD who underwent three or more consecutive anti-VEGF injections. The patients were divided into three groups according to their changes of visual acuity (VA); improved (group I), static (group S), or worsened (group W). We assessed the incidences and values of all available SD-OCT findings of these groups, compared these findings between the three groups and compared the initial values with the post-treatment values. RESULTS: Better initial VA and longer external limiting membrane (ELM) length were associated with less change in VA after anti-VEGF treatment. The initial VA was mildly correlated with initial photoreceptor inner and outer segment junction (IS/OS) length and initial ELM length. The final VA was also mildly correlated with the final IS/OS length and the final ELM length. VA was significantly changed after anti-VEGF treatment in groups W and I. With regard to incidence, disruption of the IS/OS (IS/OS-D), disruption of the ELM (ELM-D) and ELM length differed significantly between the three groups, particularly ELM-D. The incidences of IS/OS-D and ELM-D in group I were significantly lower than those in groups S and W, and those in group S were also lower than those in group W. The ELM length in group I was significantly longer than it was in groups S and W, and the ELM length in group S was longer than that for group W. However, these three findings did not change after the anti-VEGF treatment. CONCLUSIONS: Initial IS/OS-D, ELM length and particularly ELM-D can be useful predictors of the visual outcome after anti-VEGF treatment in NV-AMD patients.


Assuntos
Inibidores da Angiogênese/uso terapêutico , Neovascularização de Coroide/tratamento farmacológico , Ranibizumab/uso terapêutico , Acuidade Visual/fisiologia , Degeneração Macular Exsudativa/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Neovascularização de Coroide/fisiopatologia , Feminino , Humanos , Injeções Intravítreas , Masculino , Pessoa de Meia-Idade , Segmento Interno das Células Fotorreceptoras da Retina/patologia , Segmento Externo das Células Fotorreceptoras da Retina/patologia , Tomografia de Coerência Óptica , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Degeneração Macular Exsudativa/fisiopatologia
19.
J Hazard Mater ; 265: 201-7, 2014 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-24361799

RESUMO

In aqueous solution, zero-valent iron (ZVI, Fe(0)) is known to activate oxygen (O2) into reactive oxidants such as hydroxyl radical and ferryl ion capable of oxidizing contaminants. However, little is known about the effect of the particle size of ZVI on the yield of reactive oxidants. In this study, the production of reactive oxidants from nanoparticulate and microparticulate ZVIs (denoted as nZVI and mZVI, respectively) was comparatively investigated in the presence of O2 and EDTA. To quantify the oxidant yield, excess amount of methanol was employed, and the formation of its oxidation product, formaldehyde (HCHO), was monitored. The concentration of HCHO in the nZVI/O2 system rapidly reached the saturation value, whereas that in the mZVI/O2 system gradually increased throughout the entire reaction time. The mZVI/O2 system exhibited higher yields of HCHO than the nZVI/O2 system under both acidic and neutral pH conditions. The higher oxidant yields in the mZVI/O2 system are mainly attributed to the less reactivity of the mZVI surface with hydrogen peroxide (H2O2) relative to the surface of nZVI, which minimize the loss of H2O2 by ZVI (i.e., the two-electron reduction of H2O2 into water). In addition, the slow dissolution of Fe(II) from mZVI was found to be partially responsible for the higher oxidant yields at neutral pH.


Assuntos
Formaldeído/química , Ferro/química , Nanopartículas Metálicas/química , Oxidantes/química , Corrosão , Ácido Edético/química , Oxigênio/química
20.
Environ Sci Technol ; 47(23): 13661-7, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24180265

RESUMO

The cupric ion mediated inactivation of Escherichia coli was enhanced by the presence of hydrogen peroxide (H2O2), with increasing inactivation efficacy observed in response to increasing concentrations of H2O2. The biocidal activity of the Cu(II)/H2O2 system is believed to result from the oxidative stress caused by reactive oxidants such as the hydroxyl radical ((•)OH), cupryl species (Cu(III)), and the superoxide radical (O2(•-)), which are produced via the catalytic decomposition of H2O2. In E. coli cells treated with Cu(II) and H2O2, the intracellular level of (•)OH and Cu(III) increased significantly, leading to complete disruption of cell membranes. On the basis of experimental observations made using an (•)OH scavenger, copper-chelating agents, and superoxide dismutase, it is concluded that Cu(III) is the predominant species responsible for the death of E. coli cells. It was also found that the production of Cu(III) was promoted by the reactions of copper with intracellular O2(•-). MS2 coliphage was found to be even more susceptible than E. coli to the oxidative stress induced by the Cu(II)/H2O2 system.


Assuntos
Anti-Infecciosos/farmacologia , Cobre/farmacologia , Escherichia coli/efeitos dos fármacos , Peróxido de Hidrogênio/farmacologia , Viabilidade Microbiana/efeitos dos fármacos , Oxidantes/farmacologia , Anti-Infecciosos/metabolismo , Catálise , Quelantes/metabolismo , Cobre/metabolismo , Escherichia coli/ultraestrutura , Escherichia coli/virologia , Fluorescência , Peróxido de Hidrogênio/metabolismo , Radical Hidroxila/química , Levivirus/fisiologia , Microscopia Eletrônica de Transmissão , Oxidantes/metabolismo , Estresse Oxidativo , Superóxido Dismutase/metabolismo , Superóxidos/química
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