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1.
Several neurodegenerative diseases and brain injury involve reactive oxygen species and implicate oxidative stress in disease mechanisms. Hydrogen peroxide (H2O2) formation due to mitochondrial superoxide leakage perpetuates oxidative stress in neuronal injury. Catalase, an H2O2-degrading enzyme, thus remains an important antioxidant therapy target. However, catalase therapy is restricted by its labile nature and inadequate delivery. Here, a nanotechnology approach was evaluated using catalase-loaded, poly(lactic co-glycolic acid) nanoparticles (NPs) in human neuronal protection against oxidative damage. This study showed highly efficient catalase encapsulation capable of retaining∼99% enzymatic activity. NPs released catalase rapidly, and antioxidant activity was sustained for over a month. NP uptake in human neurons was rapid and nontoxic. Although human neurons were highly sensitive to H2O2, NP-mediated catalase delivery successfully protected cultured neurons from H2O2-induced oxidative stress. Catalase-loaded NPs significantly reduced H2O2-induced protein oxidation, DNA damage, mitochondrial membrane transition pore opening and loss of cell membrane integrity and restored neuronal morphology, neurite network and microtubule-associated protein-2 levels. Further, catalase-loaded NPs improved neuronal recovery from H2O2 pre-exposure better than free catalase, suggesting possible applications in ameliorating stroke-relevant oxidative stress. Brain targeting of catalase-loaded NPs may find wide therapeutic applications for oxidative stress-associated acute and chronic neurodegenerative disorders. 相似文献
2.
Tammineni Venkata Surendra Selvaraj Mohana Roopan Maksudur R. Khan 《Biotechnology progress》2019,35(4):e2823
The rare earth metal oxide nanoparticles such as gadolinium oxide nanoparticles (Gd2O3 NPs) have been synthesized by green synthesis process using methanolic extract of Moringa oleifera (M oleifera) peel. In this process, the Gd2O3 NPs formation was observed at 280–300 nm in UV–Vis spectroscopy. The XRD pattern of the synthesized Gd2O3 NPs was exactly matched with JCPDS No 3-065-3181which confirms the crystalline nature of Gd2O3 NPs. In addition, Energy-dispersive X-ray spectroscopy (EDX) analysis was stated that Gd and O elements were present as 70.31 and 29.69%, respectively in Gd2O3 NPs. The SEM and TEM analysis were said Gd2O3 NPs are in rod shape and 26 ± 2 nm in size. Further the synthesized Gd2O3 NPs were confirmed by X-ray photoemission spectroscopy (XPS). The synthesized Gd2O3 NPs were further examined for anti-fungal activity against Alternaria saloni (A saloni) and Sclerrotium rolfsii (S rolfsii) and it showed moderate activity. Also, Gd2O3 NPs evaluated as good antibacterial agent against different Gram +ve and Gram −ve bacteria. Moreover, the toxicity of the Gd2O3 NPs on red blood cells (RBCs) of the human blood was determined using hemolytic assay, the obtained results were stated the synthesized Gd2O3 NPs are nontoxic to the human erythrocytes. The photocatalytic activity against malachite green (MG) dye was tested and confirmed as 92% of dye was degraded within 2 hr by Gd2O3 NPs. The results were stated the green synthesized Gd2O3 NPs are good anti-fungal agents, nontoxic and we can use as a photocatalyst. Copyright © 2019 John Wiley & Sons, Ltd. 相似文献
3.
H. N. Ravishankar Aparna V. S. Rao T. Ramasarma 《Molecular and cellular biochemistry》1996,154(2):101-106
Sequential addition of vanadyl sulfate to a phosphate-buffered solution of H2O2 released oxygen only after the second batch of vanadyl. Ethanol added to such reaction mixtures progressively decreased oxygen release and increased oxygen consumption during oxidation of vanadyl by H2O2. Inclusion of ethanol after any of the three batches of vanadyl resulted in varying amounts of oxygen consumption, a property also shared by other alcohols (methanol, propanol and octanol). On increasing the concentration of ethanol, vanadyl sulfate or H2O2, both oxygen consumption and acetaldehyde formation increased progressively. Formation of acetaldehyde decreased with increase in the ratio of vanadyl:H2O2 above 2:1 and was undetectable with ethanol at 0.1 mM. The reaction mixture which was acidic in the absence of phosphate buffer (pH 7.0), released oxygen immediately after the first addition of vanadyl and also in presence of ethanol soon after initial rapid consumption of oxygen, with no accompanying acetaldehyde formation. The results underscore the importance of some vanadium complexes formed during vanadyl oxidation in the accompanying oxygen-transfer reactions. 相似文献
4.
PurposeTitanium dioxide nanoparticles (TiO2 NPs) have been investigated for their role as radiosensitisers for radiation therapy. The study aims to increase the efficiency of these NPs by synthesising them with samarium.MethodsSamarium-doped TiO2 NPs (Ti(Sm)O2 NPs) were synthesised using a solvothermal method. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS) were performed for characterising of the Ti(Sm)O2 NPs. The intracellular uptake and cytotoxicity were assessed in vitro using A549 and DU145 cancer cell lines. Furthermore, the effect of dose enhancement and generation of reactive oxygen species (ROS) in response to 6 MV X-rays was evaluated. Additionally, the image contrast properties were investigated using computed tomography (CT) images.ResultsThe synthesised Ti(Sm)O2 NPs were about 13 nm in diameter as determined by TEM. The XRD pattern of Ti(Sm)O2 NPs was consistent with that of anatase-type TiO2. EDS confirmed the presence of samarium in the nanoparticles. At 200 μg/ml concentration, no differences in cellular uptake and cytotoxicity were observed between TiO2 NPs and Ti(Sm)O2 NPs in both A549 and DU145 cells. However, the combination of Ti(Sm)O2 NPs and X-rays elicited higher cytotoxic effect and ROS generation in the cells than that with TiO2 NPs and X-rays. The CT numbers of Ti(Sm)O2 NPs were systematically higher than that of TiO2 NPs.ConclusionsThe Ti(Sm)O2 NPs increased the dose enhancement of MV X-ray beams than that elicited by TiO2 NPs. Samarium improved the efficiency of TiO2 NPs as potential radiosensitising agent. 相似文献
5.
Determination of ampicillin sodium using the cupric oxide nanoparticles–luminol–H2O2 chemiluminescence reaction
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A simple and sensitive chemiluminescence (CL) method has been developed for the determination of ampicillin sodium at submicromolar levels. The method is based on the inhibitory effect of ampicillin sodium on the cupric oxide nanoparticles (CuO NPs)–luminol–H2O2 CL reaction. Experimental parameters affecting CL inhibition including concentrations of CuO NPs, luminol, H2O2 and NaOH were optimized. Under optimum conditions, the calibration plot was linear in the analyte concentration range 4.0 × 10‐7–4.0 × 10‐6 mol/L. The limit of detection was 2.6 × 10‐7 mol/L and the relative standard deviation (RSD) for six replicate determinations of 1 × 10‐6 mol/L ampicillin sodium was 4.71%. Also, X–ray diffraction (XRD) and transmission electron microscopy (TEM) analysis were employed to characterize the CuO NPs. The utility of the proposed method was demonstrated by determining ampicillin sodium in pharmaceutical preparation. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
6.
Enzhou Liu Limin Kang Feng Wu Tao Sun Xiaoyun Hu Yuhao Yang Hanchen Liu Jun Fan 《Plasmonics (Norwell, Mass.)》2014,9(1):61-70
Ag-loaded TiO2 (Ag/TiO2) nanocomposites were prepared by microwave-assisted chemical reduction method using tetrabutyl titanate as the Ti source. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption–desorption isotherms, UV–vis absorption spectrum, X-ray photoelectron spectrum, photoluminescence spectrum, and Raman scattering spectrum, respectively. Results revealed that Ag nanoparticles (NPs) were successfully deposited on TiO2 by reduction of Ag+, and the visible light absorption and Raman scattering of TiO2 were enhanced by Ag NPs based on its surface plasmon resonance effect. Besides, Ag NPs could also effectively restrain the recombination of photogenerated electrons and holes with a longer luminescence life time. In addition, photocatalytic reduction of CO2 with H2O on the composites was conducted to obtain methanol. Experimental results indicated that Ag-loaded TiO2 had better photocatalytic activity than pure TiO2 due to the synergistic effect between UV light excitation and surface plasmon resonance enhancement, and 2.5 % Ag/TiO2 exhibited the best activity; the corresponding energy efficiency was about 0.5 % and methanol yield was 405.2 μmol/g-cat, which was 9.4 times higher than that of pure TiO2. Additionally, an excitation enhancement synergistic mechanism was proposed to explain the experimental results of photocatalytic reduction of CO2 under different reaction conditions. 相似文献
7.
Magnetic targeted drug delivery (MTD), using magnetic gold nanoparticles (Fe3O4@Au NPs) conjugated with an anti-cancer drug is a promise modality for cancer treatment. In this study, Fe3O4@Au NPs were prepared and functionalized with thiol-terminated polyethylene glycol (PEG), then loaded with anti-cancer drug doxorubicin (DOX). The physical properties of the prepared NPs were characterized using different techniques. Transmission electron microscopy (TEM) revealed the mono dispersed nature of Fe3O4@Au NPs with an average size of 20 nm which was confirmed using Dynamic light scattering (DLS) measurements. Zeta potential measurements along with UV–VIS spectroscopy demonstrated surface DOX loading on Fe3O4@Au NPs. Energy Dispersive X-ray Spectroscopy (EDX) assured the existence of both iron and gold elements in the prepared NPs. The paramagnetic properties of the prepared NPs were assessed by vibrating sample magnetometer (VSM). The maximum DOX-loading capacity was 100 μg DOX/mg of Fe3O4@Au NPs. It was found that DOX released more readily at acidic pH. In vitro studies on MCF-7 cell line elucidated that DOX loaded Fe3O4@Au NPs (Fe3O4@Au-PEG-DOX) have more potent therapeutic effect than free DOX. Knowledge gained in this study may open the door to pursue Fe3O4@Au NPs as a viable nanocarriers for different molecules delivery in many diagnostic and therapeutic applications. 相似文献
8.
Pretreatments for enzymatic saccharification are crucial for the establishment of lignocellulosic biorefineries. In this study, we focused on ammonium ions and peroxometal complexes as potential delignifying agents. We first examined the pretreatment of beech wood with nine different ammonium salts in the presence of H2O2. Significant pretreatment effects were found only for ammonium molybdate, which is transformed to a peroxometal complex on reacting with H2O2. Since microwave sensitizer effects are expected for (peroxo)molybdate, beech wood was pretreated using external heating and microwave irradiation. As a result, a maximum sugar yield of 59.5% was obtained by microwave irradiation at 140 °C for 30 min, while external heating in an autoclave gave a sugar yield of 41.8%. We also found that an ammonium ion is the key counterion accelerating the pretreatment with molybdate. These results highlight the powerful selective delignifying capability of the H2O2-activated ammonium molybdate system energised by microwave radiation. 相似文献
9.
To improve xanthan gum productivity, a strategy of adding hydrogen peroxide (H2O2) was studied. The method could intensify oxygen supply through degradation of H2O2 to oxygen (O2). In shake flask testing, the xanthan gum yield reached 2.8% (improved by 39.4%) when adding 12.5 mM H2O2 after 24 h of fermentation. In fermentor testing, it was obvious that the oxygen conditions varied with the H2O2 addition time. Eventually, gum yield of 4.2% (w/w) was achieved (increased by 27.3%). Compared with the method of intense
mixing and increasing the air flow rate, adding H2O2 to improve the dissolved oxygen concentration was more effective and much better. Moreover, addition of H2O2 improved the quality of xanthan gum; the pyruvate content of xanthan was 4.4% (w/w), higher than that of the control (3.2%). 相似文献
10.
Gelavizh Barzegar Reza Darvishi Cheshmeh Soltani Mehdi Ahmadi Reza Saeedi Mehrnoosh Abtahi 《Soil & Sediment Contamination》2017,26(5):538-557
In the current study, Fe3O4 NPs were synthesized and used as catalysts in a sono-Fenton-like process for remediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soil. The effects of operational variables were studied using central composite design (CCD) optimization approach. Results indicated that the effects of H2O2 concentration, Fe3O4 NPs dosage, ultrasonic power and pH were significant for pyrene removal as a contaminant model. In optimum experimental conditions, including H2O2 concentration of 78 mM, Fe3O4 NPs dosage of 18 mM, ultrasonic power of 313 W and pH value of 3.46, the observed pyrene removal was obtained 98.37%, which was verified through the additional experimental tests (99.33%). Pseudo first-order kinetic model was well fitted with the experimental data of pyrene removal with significant coefficient of correlation (R2: 0.9672). Accordingly, an unwashed real soil sample containing diffident PAHs (pyrene, flurene, acenaphthylene, phenenthrene, chrysene, etc) was subjected to sono-Fenton-like process based on optimized conditions. The obtained findings revealed that the removal (%) ranged between 37.7% and 85.19% for different PAHs. 相似文献
11.
《生物化学与生物物理学报:疾病的分子基础》2014,1842(7):927-934
Glial cell line-derived neurotrophic factor (GDNF) is a potent neuroprotective molecule for dopaminergic neurons of the nigrostriatal pathway that degenerate in Parkinson's disease. We have previously shown that H2O2- or l-3,4-dihydroxyphenylalanine (l-DOPA)-challenged dopaminergic neurons trigger the release of soluble factors that signal ventral midbrain astrocytes to increase GDNF expression. In the present work, we evaluated whether the factors released by ventral midbrain-challenged cells were able to alter GDNF expression in striatal cells, the targets of dopaminergic neurons projecting from the substantia nigra, and investigated the signalling pathways involved. Our data showed that soluble mediators released upon H2O2- or l-DOPA-induced dopaminergic injury up-regulated GDNF in striatal cells, with different temporal patterns depending on the oxidative agent used. Conditioned media from H2O2- or l-DOPA-challenged midbrain astrocyte cultures failed to up-regulate GDNF in striatal cultures. Likewise, there was no direct effect of H2O2 or l-DOPA on striatal GDNF levels suggesting that GDNF up-regulation was mediated by soluble factors released in the presence of failing dopaminergic neurons. Both phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways were involved in striatal GDNF up-regulation triggered by H2O2-induced dopaminergic injury, while diffusible factors released in the presence of l-DOPA-challenged dopaminergic neurons induced GDNF expression in striatal cells through the activation of the MAPK pathway. These soluble mediators may constitute, in the future, important targets for the control of endogenous GDNF expression enabling the development of new and, hopefully, more efficient neuroprotective/neurorestorative strategies for the treatment of Parkinson's disease. 相似文献
12.
A sensitive peroxidase-dependent luminol-enhanced chemiluminescence (ECL) assay for determination of hydrogen peroxide (H2O2) generation by tumour cells was established. This test system allows determination of H2O2 in concentrations as low as 25 pmol (50nmol/L) and yields results which are comparable to those obtained using a less sensitive photometric method and a previously described scopoletin flurorescence assay. After 3h incubation time 104SK-N-SH neuroblastoma cells released 60° 5 pmol H2O2 in the supernatant and this level was significantly (p<0.025) increased by about 70% in the presence of 5pmol (100 ng/mL) recombinant tumour necrosis factor α (TNFα). In contrast, H2O2 production was slightly reduced by TNFα at a very low concentration of 0.5 fmol (0.01 ng/mL). 相似文献
13.
Inhibition of lipid peroxidation 总被引:1,自引:0,他引:1
Enjie Sun Huibi Xu Dijiang Wen Ping Zuo Jingyan Zhou Jünjian Wang 《Biological trace element research》1997,59(1-3):87-92
Lipid peroxy radicals (ROO-) were detected by electron spin resonance (ESR) at low temperature after formation by addition
of H2O2 into a suspension of mice lymphocites. If lymphocytes were treated with selenomethionine (Se-Met) prior to addition of H2O2, ROO-formation was inhibited in a fashion that was dependent on Se-Met concentration. Formation of ROO- in the spleen of
mice was induced by60Co irradiation. Animals that were supplemented with Na2SeO3 prior to irradiation exhibited a lower ROO-concentration than that of nontreated animals. Based on our experiments, we have
concluded that Se has an oxygen-free radical scavenging effect. This should be a protective effect against lipid peroxy radical
cellular attack. 相似文献
14.
Cupric oxide nanoparticles‐enhanced chemiluminescence method for measurement of β‐lactam antibiotics
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A simple, sensitive cupric oxide nanoparticles (CuO NPs) enhanced chemiluminescence (CL) method was developed for the measurement of β‐lactam antibiotics, including amoxicillin and cefazolin sodium. The method was based on suppression of the CuO NPs–luminol–H2O2 CL reaction by β‐lactam antibiotics. Experimental parameters that influenced the inhibitory effect of the antibiotic drugs on the CL system, such as NaOH (mol/L), luminol (µmol/L), H2O2 (mol/L) and CuO NPs (mg/L) concentrations, were optimized. Calibration graphs were linear and had dynamic ranges of 1.0 × 10–6 to 8.0 × 10–6 mol/L and 3.0 × 10–5 to 5.0 × 10–3 mol/L for amoxicillin and cefazolin sodium, respectively, with corresponding detection limits of 7.9 × 10–7 mol/L and 1.8 × 10–5 mol/L. The relative standard deviations of five replicate measurements of 5.0 × 10–6 amoxicillin and 5 × 10–4 cefazolin sodium were 5.43 and 5.01%, respectively. The synthesized CuO NPs were characterized by X‐ray diffraction (XRD) and transmission electronmicroscopy (TEM). The developed approach was exploited successfully to measure antibiotics in pharmaceutical preparations. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
15.
《Experimental cell research》1981,134(1):65-72
O2 consumption of an Arbacia egg homogenate is stimulated by addition of millimolar calcium concentrations. The O2 consumption is calcium-dependent, cyanide-insensitive, non-mitochondrial and associated with the pigment granules. The purified naphthoquinone pigment of the pigment granules, echinochrome A, also undergoes a Ca2+-stimulated oxidation with similar behavior—with respect to Ca2+ and H+ concentrations—as the homogenate O2 consumption. This oxidation of echinochrome accounts for the bulk of the Ca2+-stimulated homogenate O2 consumption. The Ca2+-stimulated oxidation results in the production of H2O2. As naphthoquinone pigment is released by eggs and the extent of release is increased at fertilization, this Ca2+-mediated oxidation of the pigment may be the source of H2O2 used in hardening the fertilization membrane. Ca2+-mediated echinochrome oxidation might also function in an antibacterial role. 相似文献
16.
Min Fengling Liu Fenju Wen Wanxin Zhai Lijia Tong Jiandong Wang Zu Yuan Xin Gao Qingxiang 《Radiation and environmental biophysics》2009,48(4):371-378
Clinical trials with rituximab in combination with chemotherapeutic regimens have shown promising results. Data on the effects
of rituximab treatment in combination with irradiation are, however, limited and inconsistent. This study aims to investigate
the effects of rituximab (R) on cell death induced by X-irradiation in Raji lymphoma cells and to evaluate its mechanisms.
We found the cell growth inhibition by irradiation was enhanced by additional rituximab exposure both in cells precultured
with rituximab followed by irradiation (R + irradiation) or in cells treated in the reverse sequence (irradiation + R). R + irradiation
combination treatment induced more apoptotic cells than irradiation and irradiation + R treatment as early as 12 h after treatment.
At 24 h, both combination treatments, R + irradiation and irradiation + R, showed apoptotic cells, which were significantly
different from irradiation alone. G2/M cell cycle arrest was observed after irradiation alone and the combination treatment.
The combination treatment revealed an elevation in reactive oxygen species (ROS) generation in a radiation dose-dependent
manner. In addition, rituximab enhanced the cell growth inhibition and apoptotic cell death induced by the oxidative agent,
H2O2. We propose that rituximab mediates a significant in vitro radiosensitizing effect and induces cell cycle changes and apoptosis
in Raji cells. ROS probably play an important role in these events. 相似文献
17.
Silvia Bortolami 《Free radical research》2013,47(5):446-456
A new procedure for fluorescent detection of intracellular H2O2 in cells transiently expressing the catalyst Horseradish Peroxidase (HRP) is setup and validated. More specific reaction with HRP largely amplifies oxidation of the redox probes used (2′,7′-dichlorodihydrofluorescein and dihydrorhodamine). Expression of HRP does not affect cell viability. The procedure reveals MAO activity, a primary intracellular H2O2 source, in monolayers of intact transfected cells. The probes oxidation rate responds specifically to the MAO activation/inhibition. Their oxidation by MAO-derived H2O2 is sensitive to intracellular H2O2 competitors: it decreases when H2O2 is removed by pyruvate and it increases when the GSH-dependent removal systems are impaired. Specific response was also measured after addition of extracellular H2O2. Oxidation of the fluorescent probes following reaction of H2O2 with endogenous HRP overcomes most criticisms in their use for intracellular H2O2 detection. The method can be applied for direct determination in plate reader and is proposed to detect H2O2 generation in physio-pathological cell models. 相似文献
18.
In the medium of H2SO4 and in the presence of TiO2+, gold nanoparticles in size of 10 nm exhibited a weak surface plasmon resonance scattering (SPRS) peak at 775 nm. Upon addition
of trace H2O2, the yellow complex [TiO(H2O2)]2+ formed that cause the gold nanoparticles aggregations to form bigger gold nanoparticle clusters in size of about 900 nm,
and the SPRS intensity at 775 nm (I) enhanced greatly. The enhanced intensity ΔI was linear to the H2O2 concentration in the range of 0.025–48.7 μg/mL, with a detection limit of 0.014 μg/mL H2O2. This SPRS method was applied to determining H2O2 in water samples with satisfactory results. 相似文献
19.
Transient receptor potential melastatin 2 (TRPM2) is an oxidative stress-sensitive Ca2+-permeable channel. In monocytes/macrophages, H2O2-induced TRPM2 activation causes cell death and/or production of chemokines that aggravate inflammatory diseases. However, relatively high concentrations of H2O2 are required for activation of TRPM2 channels in vitro. Thus, in the present study, factors that sensitize TRPM2 channels to H2O2 were identified and subsequent physiological responses were examined in U937 human monocytes. Temperature increase from 30 °C to 37 °C enhanced H2O2-induced TRPM2-mediated increase in intracellular free Ca2+ ([Ca2+]i) in TRPM2-expressing HEK 293 cells (TRPM2/HEK cells). The H2O2-induced TRPM2 activation enhanced by the higher temperature was dramatically sensitized by intracellular Fe2+-accumulation following pretreatment with FeSO4. Thus intracellular Fe2+-accumulation sensitizes H2O2-induced TRPM2 activation at around body temperature. Moreover, intracellular Fe2+-accumulation increased poly(ADP-ribose) levels in nuclei by H2O2 treatment, and the sensitization of H2O2-induced TRPM2 activation were almost completely blocked by poly(ADP-ribose) polymerase inhibitors, suggesting that intracellular Fe2+-accumulation enhances H2O2-induced TRPM2 activation by increase of ADP-ribose production through poly(ADP-ribose) polymerase pathway. Similarly, pretreatment with FeSO4 stimulated H2O2-induced TRPM2 activation at 37 °C in U937 cells and enhanced H2O2-induced ERK phosphorylation and interleukin-8 (CXCL8) production. Although the addition of H2O2 to cells under conditions of intracellular Fe2+-accumulation caused cell death, concentration of H2O2 required for CXCL8 production was lower than that resulting in cell death. These results indicate that intracellular Fe2+-accumulation sensitizes TRPM2 channels to H2O2 and subsequently produces CXCL8 at around body temperature. It is possible that sensitization of H2O2-induced TRPM2 channels by Fe2+ may implicated in hemorrhagic brain injury via aggravation of inflammation, since Fe2+ is released by heme degradation under intracerebral hemorrhage. 相似文献
20.
M.A. Symonyan R.M. Nalbandyan 《Biochimica et Biophysica Acta (BBA)/General Subjects》1979,583(3):279-286
Superoxide radicals in high concentrations were generated from alkaline H2O2 without using catalysts or irradiation. The dependence of the intensity and parameters of the superoxide radical EPR spectrum on pH, temperature, viscosity and H2O2 concentration were studied. The observed changes are explained on the base of matrix effects. The addition of superoxide dismutase to alkaline H2O2 led initially to a drop in the EPR spectrum intensity, followed by an increase in the concentration of superoxide radicals. 相似文献