Oxidized

  • 文章类型: Journal Article
    研究了通过氧化魔芋葡甘聚糖(OKGM)表面修饰来增强原花青素脂质体(PC-Lip)的稳定性。OKGM包被的PC-Lip(OKGM-PC-Lip)的包封率和载药量显著上升。OKGM-PC-Lip的平均大小和PDI增加,而zeta电位与PC-Lip相比降低。用OKGM涂覆后,PC-唇膜流动性降低。OKGM-PC-Lip的形态表明在脂质体表面形成了OKGM“晕层”。氢键在OKGM和PC-Lip的结合中起着不可或缺的作用,用OKGM涂覆后,PC-Lip的相变温度略有升高。OKGM-PC-Lip在极端pH下的保留率高于PC-Lip。体外释放,在胃期,OKGM-PC-Lip和PC-Lip之间的累积释放没有显着差异,肠道期OKGM-PC-Lip的累积释放速率明显低于PC-Lip。OKGM-PC-Lip的抗氧化活性明显高于PC-Lip。这些结果表明,用OKGM涂覆后,PC-Lip对外部影响的抵抗力得到了有效增强。与其他多糖相比,由于多糖对人体健康的益处,OKGM包被的脂质体在功能性食品中可能更有前途和优势。
    The stability enhancement of proanthocyanidin-loaded liposomes (PC-Lip) via surface decoration with oxidized konjac glucomannan (OKGM) was investigated. The encapsulation efficiency and drug loading capacity of OKGM-coated PC-Lip (OKGM-PC-Lip) rose significantly. The average size and PDI of OKGM-PC-Lip increased, while the zeta potential decreased compared to those of PC-Lip. PC-Lip membrane fluidity reduced after coating with OKGM. The morphology of OKGM-PC-Lip showed that OKGM \"halo layer\" was formed on the liposome surface. Hydrogen bonding played an indispensable role in the combination between OKGM and PC-Lip, and the phase transition temperature of PC-Lip slightly increased after coating with OKGM. The retention rate of OKGM-PC-Lip was higher than that of PC-Lip at extreme pH. In vitro release, no significant difference in cumulative release was detected between OKGM-PC-Lip and PC-Lip at gastric stage, while the cumulative release rate of OKGM-PC-Lip was remarkably lower than that of PC-Lip at intestinal stage. The antioxidant activity of OKGM-PC-Lip was notably higher than that of PC-Lip. These results suggested that the resistance of PC-Lip to external influences was fruitfully enhanced after coating with OKGM. Compared with other polysaccharides, OKGM-coated liposomes may be more promising and advantageous in functional foods due to the polysaccharide\'s benefits to human health.
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  • 文章类型: Journal Article
    以前大多数氧化汞的测量是使用现在已知的低偏置方法收集的。在这项研究中,在科罗拉多州SteamboatSprings的山顶站点上,与基于渗透管的自动校准器一起部署了氧化汞检测极限为6-12pgm-3的双通道系统,美国,2021年和2022年。含有元素汞和卤化汞的渗透管在部署到校准器之前,通过国际单位制(SI)可追溯的重量分析法和气相色谱/质谱法进行了表征。双通道系统分别回收了97±4和100±8%(±标准偏差)的注入元素汞和HgBr2。重量法测定的总汞渗透率和汞形态,色谱系统,双通道系统,在JoçefStefan研究所实验室进行的独立SI可追溯测量方法在每种方法的各自不确定度内都具有可比性。这些是在低环境浓度下对氧化汞的首次测量,在对环境空气进行采样的同时,在现场条件下对SI可追踪校准系统进行了验证。他们显示了准确的,常规校准的氧化汞测量是可以实现的。
    Most previous measurements of oxidized mercury were collected using a method now known to be biased low. In this study, a dual-channel system with an oxidized mercury detection limit of 6-12 pg m-3 was deployed alongside a permeation tube-based automated calibrator at a mountain top site in Steamboat Springs Colorado, USA, in 2021 and 2022. Permeation tubes containing elemental mercury and mercury halides were characterized via an International System of Units (SI)-traceable gravimetric method and gas chromatography/mass spectrometry before deployment in the calibrator. The dual-channel system recovered 97 ± 4 and 100 ± 8% (±standard deviation) of injected elemental mercury and HgBr2, respectively. Total Hg permeation rates and Hg speciation from the gravimetric method, the chromatography system, the dual-channel system, and an independent SI-traceable measurement method performed at the Jožef Stefan Institute laboratory were all comparable within the respective uncertainties of each method. These are the first measurements of oxidized mercury at low environmental concentrations that have been verified against an SI-traceable calibration system in field conditions while sampling ambient air, and they show that accurate, routinely calibrated oxidized mercury measurements are achievable.
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  • 文章类型: Journal Article
    硬化蛋白(SOST)由骨细胞产生,被称为骨稳态的负调节剂。甲状旁腺激素(PTH)调节钙,磷酸盐和维生素D的代谢,是体内外SOST合成的强抑制剂。PTH具有两个可被氧化的甲硫氨酸氨基酸(位置8和18)。在Met18氧化的PTH(Met18(ox)-PTH)继续具有生物活性,而PTH在Met8氧化(Met8(ox)-PTH)或PTH在Met8和Met18氧化(Met8,Met18(di-ox)-PTH)具有较小的生物活性。非氧化PTH(n-oxPTH)和氧化形式的PTH如何作用于硬化素合成是未知的。在UMR106成骨细胞样细胞中评估了n-oxPTH和PTH的氧化形式对SOST基因表达的影响。此外,我们分析了516例稳定肾移植受者中SOST与n-oxPTH和所有形式的oxPTH的关系,该系统可以在临床样本中区分n-oxPTH和所有氧化PTH形式的总和(Met8(ox)-PTH,Met18(ox)-PTH,和Met8,Met18(di-ox)-PTH。我们发现,n-oxPTH和Met18(ox)-PTH在1、3、20和30nmol/L的剂量下均显着抑制SOST基因的表达,而Met8(ox)-PTH和Met8,Met18(di-ox)-PTH对SOST基因表达的抑制作用较弱。在临床队列中,多元线性回归表明,只有n-oxPTH,但不是完整的PTH(iPTH)或oxPTH,在调整已知的混杂因素后,与循环SOST独立相关。总之,只有生物活性PTH形式,如n-oxPTH和Met18(ox)-PTH,抑制SOST合成。
    Sclerostin (SOST) is produced by osteocytes and is known as a negative regulator of bone homeostasis. Parathyroid hormone (PTH) regulates calcium, phosphate as well as vitamin D metabolism, and is a strong inhibitor of SOST synthesis in vitro and in vivo. PTH has two methionine amino acids (positions 8 and 18) which can be oxidized. PTH oxidized at Met18 (Met18(ox)-PTH) continues to be bioactive, whereas PTH oxidized at Met8 (Met8(ox)-PTH) or PTH oxidized at Met8 and Met18 (Met8, Met18(di-ox)-PTH) has minor bioactivity. How non-oxidized PTH (n-oxPTH) and oxidized forms of PTH act on sclerostin synthesis is unknown. The effects of n-oxPTH and oxidized forms of PTH on SOST gene expression were evaluated in UMR106 osteoblast-like cells. Moreover, we analyzed the relationship of SOST with n-oxPTH and all forms of oxPTH in 516 stable kidney transplant recipients using an assay system that can distinguish in clinical samples between n-oxPTH and the sum of all oxidized PTH forms (Met8(ox)-PTH, Met18(ox)-PTH, and Met8, Met18(di-ox)-PTH). We found that both n-oxPTH and Met18(ox)-PTH at doses of 1, 3, 20, and 30 nmol/L significantly inhibit SOST gene expression in vitro, whereas Met8(ox)-PTH and Met8, Met18(di-ox)-PTH only have a weak inhibitory effect on SOST gene expression. In the clinical cohort, multivariate linear regression showed that only n-oxPTH, but not intact PTH (iPTH) nor oxPTH, is independently associated with circulating SOST after adjusting for known confounding factors. In conclusion, only bioactive PTH forms such as n-oxPTH and Met18(ox)-PTH, inhibit SOST synthesis.
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  • 文章类型: Journal Article
    Mdm2促进p53的泛素化和降解,而Mdm2-p60可以与p53结合并减少Mdm2诱导的p53泛素化,以提高其稳定性。USP2a可以去泛素化和稳定Mdm2,USP2a是否可以调节Mdm2-p60需要进一步证实和阐明。我们发现氧化应激可以在转录后水平上调USP2a,并通过形成亚基间二硫键诱导USP2a被氧化。USP2a的氧化与细胞凋亡密切相关。在凋亡细胞中,氧化的USP2a具有增强的蛋白质稳定性,并通过去泛素化进一步稳定Mdm2-p60,USP2a-Mdm2-p60-p53轴在细胞凋亡中起作用。总的来说,USP2a对氧敏感,氧化USP2a通过Mdm2-p60-p53轴发挥凋亡作用,这为通过靶向USP2a调节p53凋亡信号提供了实验基础。
    Mdm2 promotes the ubiquitination and degradation of p53, while Mdm2-p60 can bind to p53 and reduce the Mdm2-induced p53 ubiquitination to improve its stability. USP2a can deubiquitinate and stabilize Mdm2, whether USP2a can regulate Mdm2-p60 needs to be further confirmed and elucidated. We found that oxidative stress can up-regulate USP2a at the post-transcriptional level and induce USP2a to be oxidized by forming inter-subunit disulfide bonds. The oxidized USP2a is closely related with cell apoptosis. In apoptotic cells, oxidized USP2a has enhanced protein stability and further stabilizes Mdm2-p60 through deubiquitination, and the USP2a-Mdm2-p60-p53 axis plays a role in cell apoptosis. Altogether USP2a is oxygen sensitive, oxidized USP2a exerts apoptotic effects through the Mdm2-p60-p53 axis, which provides an experimental basis for regulating p53 apoptotic signaling by targeting USP2a.
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  • 文章类型: Journal Article
    研究了体心立方(bcc)结构的Cr20Mn17Fe18Ta23W22耐火高熵合金(RHEA)的氧化行为以及氧化前后氢离子引起的微观缺陷。结果表明,与在800°C(6.7°C/min)下氧化Cr20Mn17Fe18Ta23W224h(ST3,Ar:O2=3:1)相比,将Cr20Mn17Fe18Ta23W22在300°C(6°C/min)下氧化2h,然后升高到800°C(5°C/min)4h的加热程序更有利于氧化物的产生,而不会在表面剥落,即,HT1(Ar:O2=1:1),HT2(Ar:O2=2:1)和HT3(Ar:O2=3:1)样品。Cr20Mn17Fe18Ta23W22RHEA的氧化主要受阳离子扩散控制,而不是与O的亲和力。发现通量为3.9×1022cm-2氢离子(60eV)辐照的HT1和HT3样品比Cr20Mn17Fe18Ta23W22RHEA具有更好的耐氢辐照性能。辐照Cr20Mn17Fe18Ta23W22中的微缺陷主要以氢气气泡形式存在,氢-空位(H-V)复合物和空位/空位簇。辐照的HT3中的微缺陷主要是空位和H-V配合物,而辐照HT1中的微缺陷主要以空位和空位簇的形式存在,因为大量的氢气被消耗以与HT1表面上的氧化物反应。在氢辐照下,HT3样品表面的氧化物比HT1表面的氧化物更稳定。
    The oxidation behavior of body-centered cubic (bcc) structure Cr20Mn17Fe18Ta23W22 refractory high-entropy alloy (RHEA) and the microdefects induced by hydrogen ions before and after oxidation were investigated. The results revealed that compared with oxidizing Cr20Mn17Fe18Ta23W22 at 800 °C (6.7 °C/min) for 4 h (ST3, Ar:O2 = 3:1), the heating procedure of oxidizing Cr20Mn17Fe18Ta23W22 at 300 °C (6 °C/min) for 2 h and then increased to 800 °C (5 °C/min) for 4 h is more conducive to the production of oxides without spalling on the surface, i.e., HT1 (Ar:O2 = 1:1), HT2 (Ar:O2 = 2:1) and HT3 (Ar:O2 = 3:1) samples. The oxidation of Cr20Mn17Fe18Ta23W22 RHEA is mainly controlled by the diffusion of cations instead of affinities with O. Additionally, HT1 and HT3 samples irradiated with a fluence of 3.9 × 1022 cm-2 hydrogen ions (60 eV) were found to have a better hydrogen irradiation resistance than Cr20Mn17Fe18Ta23W22 RHEA. The microdefects in irradiated Cr20Mn17Fe18Ta23W22 mainly existed as hydrogen bubbles, hydrogen-vacancy (H-V) complexes and vacancy/vacancy clusters. The microdefects in irradiated HT3 were mainly vacancies and H-V complexes, while the microdefects in irradiated HT1 mainly existed as vacancies and vacancy clusters, as large amounts of hydrogen were consumed to react with oxides on the HT1 surface. The oxides on the surface of the HT3 sample were more stable than those on HT1 under hydrogen irradiation.
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  • 文章类型: Journal Article
    评估两种不同表面和颈部设计的植入物和假体。登记的患者接受了骨水平,12°锥形连接植入物(诺贝尔平行,NobelBiocare;NOBEL组),阳极氧化表面(TiUnite),粗糙度为1.35μm,或经粘膜植入系统(Prama,瑞典和玛蒂娜;PRAMA组),领口收敛,ZIrTi表面,粗糙度1.4-1.7μm。两种植入物均由纯IV级钛制成,具有相似的直径和长度,根据牙科部门的可用性和患者的要求选择。早期假体输送后,患者至少填充1年.结果指标是:植入物和假体的存活率和成功率,生理边缘骨重建,牙周参数和粉红色美学评分(PES)。结果:每组15例患者被分配和治疗。在为期一年的随访中,三个病人退出了,NOBEL组一个,PRAMA组两个。在整个调查期间,所有植入物均存活,假体成功.在边缘骨丢失方面无统计学差异,牙周参数,和美学(p>0.05)。结论:由于本研究的局限性,两种植入系统均显示成功的临床结果.最后,许多其他临床和手术变量可能会影响边缘骨水平,植入物存活,和牙周参数。需要更大样本的更同质临床试验来证实这些初步结论。
    To evaluate the implant and prosthetic of two implants with different surfaces and neck design. Enrolled patients received bone level, 12° conical connection implants (Nobel Parallel, Nobel Biocare; NOBEL group) with anodized surface (TiUnite) and roughness of 1.35 μm, or transmucosal implant system (Prama, Sweden and Martina; PRAMA group) with convergent collar, ZIrTi surface, and roughness 1.4-1.7 μm. Both implants were made of pure grade IV titanium, with similar diameter and length, chosen according to the dentistry department availability and patient\'s request. After early prosthesis delivery, patients were filled for at least one year. Outcome measures were: implant and prosthetic survival and success rates, physiological marginal bone remodeling, periodontal parameters and pink esthetic score (PES). Results: Fifteen patients were allocated and treated in each group. At the one-year follow-up, three patients dropped out, one in the NOBEL group and two in the PRAMA group. During the entire time of investigation, all implants survived and the prostheses were successful. No statistically significant differences were found in term of marginal bone loss, periodontal parameters, and aesthetics (p > 0.05). Conclusion: With the limitations of the present study, both implant systems showed successful clinical results. Finally, many other clinical and surgical variables may influenced marginal bone levels, implant survival, and periodontal parameters. More homogenous clinical trials with larger samples are needed to confirm these preliminary conclusions.
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  • 文章类型: Journal Article
    To study oxidative stress in systemic lupus erythematosus (SLE) by estimating serum oxidised LDL (OxLDL), 8-hydroxy-2\'-deoxyguanosine (8-OHdG), malondialdehyde (MDA), and total anti-oxidant status and to correlate with SLE disease activity and disease damage. Eighty SLE patients satisfying the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) 2012 criteria and 80 healthy controls were studied. Exclusion criteria were infections, renal insufficiency, other connective tissue diseases, drug-induced lupus, smoking, alcohol consumption. Disease activity was measured by SLE disease activity index-2 K (SLEDAI), disease damage was quantified by SLICC-Damage Index (SDI). Sera was tested for OxLDL, 8-OHdG, and total antioxidant status (TAS) by double-antibody sandwich ELISA; MDA measured by Colorimetric assay. Oxidative stress markers were compared between group1- controls, group 2-mildly active SLE (SLEDAI ≤ 5), group 3- moderate to highly active SLE (SLEDAI ≥ 6). SLE patients had significantly higher MDA, 8-OHdG and lower TAS when compared to healthy controls, while OxLDL was similar in the three groups. MDA, 8-OHdG were significantly higher, TAS lower in group 3 compared to group 2. MDA had positive correlation with SLEDAI, TAS negatively correlated with SLEDAI. SLE with neuropsychiatric manifestations, vasculitis, anti-sdDNA antibodies had higher MDA, MDA/TAS ratio. SLE patients with thrombocytopenia, and vasculitis had higher OxLDL. Only OxLDL was significantly higher in those patients who have SDI > 1. SLE patients have increased oxidative stress measured by increases in MDA, 8-OHdG, and lower total antioxidant status that was associated with disease activity and some disease manifestations. However only OxLDL was associated with damage.
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  • 文章类型: Journal Article
    Esterification of cholesterol is a universal mechanism to store and transport large quantities of cholesterol between organs and tissues and to avoid toxicity of the excess of cellular cholesterol. Intended for transport and storage and thus to be inert, cholesteryl esters (CEs) reside in hydrophobic cores of circulating lipoproteins and intracellular lipid droplets. However, the inert identity of CEs is dramatically changed if cholesterol is esterified to a polyunsaturated fatty acid and subjected to oxidative modification. Post-synthetic, or epilipidomic, oxidative modifications of CEs are mediated by specialized enzymes, chief among them are lipoxygenases, and by free radical oxidation. The complex repertoire of oxidized CE (OxCE) products exhibit various, context-dependent biological activities, surveyed in this review. Oxidized fatty acyl chains in OxCE can be hydrolyzed and re-esterified, thus seeding oxidized moieties into phospholipids (PLs), with OxPLs having different from OxCEs biological activities. Technological advances in mass spectrometry and the development of new anti-OxCE antibodies make it possible to validate the presence and quantify the levels of OxCEs in human atherosclerotic lesions and plasma. The article discusses the prospects of measuring OxCE levels in plasma as a novel biomarker assay to evaluate risk of developing cardiovascular disease and efficacy of treatment.
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  • 文章类型: Journal Article
    Fibroblast growth factor 23 (FGF23) and parathyroid hormone (PTH) are regulators of renal phosphate excretion and vitamin D metabolism. In chronic kidney disease (CKD), circulating FGF23 and PTH concentrations progressively increase as renal function declines. Oxidation of PTH at two methionine residues (positions 8 and 18) causes a loss of function. The impact of n-oxPTH and oxPTH on FGF23 synthesis, however, and how n-oxPTH and oxPTH concentrations are affected by CKD, is yet unknown. The effects of oxidized and non-oxidized PTH 1-34 on Fgf23 gene expression were analyzed in UMR106 osteoblast-like cells. Furthermore, we investigated the relationship between n-oxPTH and oxPTH, respectively, with FGF23 in two independent patients\' cohorts (620 children with CKD and 600 kidney transplant recipients). While n-oxPTH stimulated Fgf23 mRNA synthesis in vitro, oxidation of PTH in particular at Met8 led to a markedly weaker stimulation of Fgf23. The effect was even stronger when both Met8 and Met18 were oxidized. In both clinical cohorts, n-oxPTH-but not oxPTH-was significantly associated with FGF23 concentrations, independent of known confounding factors. Moreover, with progressive deterioration of kidney function, intact PTH (iPTH) and oxPTH increased substantially, whereas n-oxPTH increased only moderately. In conclusion, n-oxPTH, but not oxPTH, stimulates Fgf23 gene expression. The increase in PTH with decreasing GFR is mainly due to an increase in oxPTH in more advanced stages of CKD.
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  • 文章类型: Journal Article
    Background Activated vascular cells produce submicron prothrombotic and proinflammatory microparticle vesicles. Atherosclerotic plaques contain high levels of microparticles. Plasma microparticle levels increase during acute coronary syndromes and the thrombotic consequences of plaque rupture likely involve macrophage-derived microparticles (MΦMPs). The activation pathways that promote MΦMP production remain poorly defined. This study tested the hypothesis that signals implicated in atherogenesis also stimulate MΦMP production. Methods and Results We stimulated human primary MΦs with proinflammatory cytokines and atherogenic lipids, and measured MΦMP production by flow cytometry. Oxidized low-density lipoprotein (oxLDL; 25 µg/mL) induced MΦMP production in a concentration-dependent manner (293% increase; P<0.001), and these oxLDL MΦMP stimulatory effects were mediated by CD36. OxLDL stimulation increased MΦMP tissue factor content by 78% (P<0.05), and oxLDL-induced MΦMP production correlated with activation of caspase 3/7 signaling pathways. Salvionolic acid B, a CD36 inhibitor and a CD36 inhibitor antibody reduced oxLDL-induced MΦMP by 67% and 60%, respectively. Caspase 3/7 inhibition reduced MΦMP release by 52% (P<0.01) and caspase 3/7 activation increased MΦMP production by 208% (P<0.01). Mevastatin pretreatment (10 µM) decreased oxLDL-induced caspase 3/7 activation and attenuated oxLDL-stimulated MΦMP production and tissue factor content by 60% (P<0.01) and 43% (P<0.05), respectively. Conclusions OxLDL induces the production of prothrombotic microparticles in macrophages. This process depends on caspases 3 and 7 and CD36 and is inhibited by mevastatin pretreatment. These findings link atherogenic signaling pathways, inflammation, and plaque thrombogenicity and identify a novel potential mechanism for antithrombotic effects of statins independent of LDL lowering.
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