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71.
72.
Reactive oxygen species generated by NADPH oxidase 5 (Nox5) have been implicated in physiological and pathophysiological signaling pathways, including cancer development and progression. However, because immunological tools are lacking, knowledge of the role of Nox5 in tumor biology has been limited; the expression of Nox5 protein across tumors and normal tissues is essentially unknown. Here, we report the characterization and use of a mouse monoclonal antibody against a recombinant Nox5 protein (bp 600–746) for expression profiling of Nox5 in human tumors by tissue microarray analysis. Using our novel antibody, we also report the detection of endogenous Nox5 protein in human UACC-257 melanoma cells. Immunofluorescence, confocal microscopy, and immunohistochemical techniques were employed to demonstrate Nox5 localization throughout UACC-257 cells, with perinuclear enhancement. Tissue microarray analysis revealed, for the first time, substantial Nox5 overexpression in several human cancers, including those of prostate, breast, colon, lung, brain, and ovary, as well as in malignant melanoma and non-Hodgkin lymphoma; expression in most nonmalignant tissues was negative to weak. This validated mouse monoclonal antibody will promote further exploration of the functional significance of Nox5 in human pathophysiology, including tumor cell growth and proliferation.  相似文献   
73.
Mutations of the gene for glucocerebrosidase 1 (GBA) cause Gaucher disease (GD), an autosomal recessive lysosomal storage disorder. Individuals with homozygous or heterozygous (carrier) mutations of GBA have a significantly increased risk for the development of Parkinson’s disease (PD), with clinical and pathological features that mirror the sporadic disease. The mechanisms whereby GBA mutations induce dopaminergic cell death and Lewy body formation are unknown. There is evidence of mitochondrial dysfunction and oxidative stress in PD and so we have investigated the impact of glucocerebrosidase (GCase) inhibition on these parameters to determine if there may be a relationship of GBA loss-of-function mutations to the known pathogenetic pathways in PD. We have used exposure to a specific inhibitor (conduritol-β-epoxide, CβE) of GCase activity in a human dopaminergic cell line to identify the biochemical abnormalities that follow GCase inhibition. We show that GCase inhibition leads to decreased ADP phosphorylation, reduced mitochondrial membrane potential and increased free radical formation and damage, together with accumulation of alpha-synuclein. Taken together, inhibition of GCase by CβE induces abnormalities in mitochondrial function and oxidative stress in our cell culture model. We suggest that GBA mutations and reduced GCase activity may increase the risk for PD by inducing these same abnormalities in PD brain.  相似文献   
74.
Secoisolariciresinol diglucosides (SDGs) (S,S)-SDG-1 (major isomer in flaxseed) and (R,R)-SDG-2 (minor isomer in flaxseed) were synthesized from vanillin via secoisolariciresinol (6) and glucosyl donor 7 through a concise route that involved chromatographic separation of diastereomeric diglucoside derivatives (S,S)-8 and (R,R)-9. Synthetic (S,S)-SDG-1 and (R,R)-SDG-2 exhibited potent antioxidant properties (EC50 = 292.17 ± 27.71 μM and 331.94 ± 21.21 μM, respectively), which compared well with that of natural (S,S)-SDG-1 (EC50 = 275.24 ± 13.15 μM). These values are significantly lower than those of ascorbic acid (EC50 = 1129.32 ± 88.79 μM) and α-tocopherol (EC50 = 944.62 ± 148.00 μM). Compounds (S,S)-SDG-1 and (R,R)-SDG-2 also demonstrated powerful scavenging activities against hydroxyl [natural (S,S)-SDG-1: 3.68 ± 0.27; synthetic (S,S)-SDG-1: 2.09 ± 0.16; synthetic (R,R)-SDG-2: 1.96 ± 0.27], peroxyl [natural (S,S)-SDG-1: 2.55 ± 0.11; synthetic (S,S)-SDG-1: 2.20 ± 0.10; synthetic (R,R)-SDG-2: 3.03 ± 0.04] and DPPH [natural (S,S)-SDG-1: EC50 = 83.94 ± 2.80 μM; synthetic (S,S)-SDG-1: EC50 = 157.54 ± 21.30 μM; synthetic (R,R)-SDG-2: EC50 = 123.63 ± 8.67 μM] radicals. These results confirm previous studies with naturally occurring (S,S)-SDG-1 and establish both (S,S)-SDG-1 and (R,R)-SDG-2 as potent antioxidants and free radical scavengers for potential in vivo use.  相似文献   
75.
目的探讨胃肝样腺癌(hepatoid adenocarcinoma of the stomach,HAS)的临床病理学特点、发生机制和免疫组化特征,以提高诊断水平。方法收集并分析5例胃肝样腺癌的临床特征和病理资料,采用HE染色、免疫组化方法,并复习文献。结果组织学胃肝样腺癌具有管状腺癌、粘液性癌和肝样分化腺癌的移行过渡,肿瘤细胞呈小梁状、巢团状,间质为丰富的血窦。免疫表型胃肝样腺癌AAT(5/5)、ACT(5/5)、CEA(5/5)、AFP(4/5)均为阳性,Heppar1灶性阳性(2/5)。结论胃肝样腺癌是一种少见的高度恶性、侵袭性强的特殊类型胃癌,组织学呈肝细胞样腺癌,免疫表型AFP、AAT和ACT阳性有助诊断。  相似文献   
76.
77.
To examine how the major elements of global change affect herbivory in agroecosystems, a multifactorial experiment was conducted where soybeans were grown at two levels of carbon dioxide and temperature, including those predicted for 2050, under otherwise normal field conditions. Japanese beetles (Popillia japonica Newman) were enclosed on foliage for 24 h, after which the beetle survivorship, total and per capita leaf consumption, and leaf protease inhibitor activity were measured. The direct effect of temperature on beetle consumption and survivorship also was measured under controlled environmental conditions. No differences in total foliage consumption were observed; however, beetles forced to feed at elevated temperature in the field demonstrated greater per capita consumption and reduced survivorship compared to beetles feeding at ambient temperature. Survivorship was also greater for beetles that consumed foliage grown under elevated CO2, but there were no interactive effects of CO2 and temperature, and no differences in leaf chemistry were resolved. Leaf consumption by beetles increased strongly with increasing temperature up to ~37° C, above which increased mortality caused a precipitous decrease in consumption. An empirical model based on the temperature dependence of leaf consumption and flight suggests that the 3.5°C increase in temperature predicted for 2050 will increase the optimal feeding window for the Japanese beetle by 290%. Elevated temperature and CO2 operating independently have the potential to greatly increase foliage damage to soybean by chewing insects, such as Popillia japonica, potentially affecting crop yields.  相似文献   
78.
To assess the biological safety of Fe3O4 nanoparticles (NPs), the oxidative-damage effect of these NPs was studied. Twenty-five Kunming mice were exposed to Fe3O4 NPs by intraperitoneai injection daily for 1 week at doses of 0, 10, 20, and 40 mg.kg1. Five Kunming mice were also injected with 40 mg.kg 1 ordinary Fe3O4 particles under the same physiological conditions. Biomarkers of reactive oxygen species (ROS), glutathione (GSH), and malondialdehyde (MDA) in the hepatic and brain tissues were detected. Results showed that no significant difference in oxidative damage existed at concentrations lower than 10 mg.kg i for NPs compared with the control group. Fe3O4 NP concentration had obvious dose-effect relationships (P〈 0.05 or P 〈 0.01) with ROS level, GSH content, and MDA content in mouse hepatic and brain tissues at〉20 mg.kg 1 concentrations. To some extent, ordinary Fe3O4 particles with 40mg.kg -1 concentration also affected hepatic and brain tissues in mice. The biological effect was similar to Fe3O4 NPs at 10 mg. kg-1 concentration. Thus, Fe3O4 NPs had significant damage effects on the antioxidant defense system in the hepatic and brain tissues of mice, whereas ordinary Fe3O4 had less influence than Fe3O4 NPs at the same concentration.  相似文献   
79.
Neurotransmitters are the compounds which allow the transmission of signals from one neuron to the next across synapses. They are the brain chemicals that communicate information throughout brain and body. Fullerenes are a family of carbonallotropes, molecules composed entirely of carbon, that take the forms of spheres, ellipsoids, and cylinders. Various empty carbon fullerenes (Cn) with different carbon atoms have been obtained and investigated. Topological indices have been successfully used to construct effective and useful mathematical methods to establish clear relationships between structural data and the physical properties of these materials. In this study, the number of carbon atoms in the fullerenes was used as an index to establish a relationship between the structures of neurotransmitters (NTs) acetylcholine (AC) 1, dopamine (DP) 2, serotonin (SE) 3, and epinephrine (EP) 4 as the well-known redox systems and fullerenes Cn (n = 60, 70, 76, 82, and 86) which create [NT].Cn; A-1 to A-5 up to D-1 to D-5. The relationship between the number of carbon atoms and the free energy of electron transfer (ΔGet(n); n = 1–4) is assessed using the Rehm-Weller equation for A-1 to A-5 up to D-1 to D-5 supramolecular [NT].Cn complexes. The calculations are presented for the four reduction potentials (Red.E1 to Red.E4) of fullerenes Cn. The results were used to calculate the four free energy values of electron transfer (ΔGet(1) to ΔGet(4)) of the supramolecular complexes A-1 to A-8 up to D-1 to D-8 for fullerenes C60 to C120. The first to fourth free activation energy values of electron transfer and the maximum wavelength of the electron transfers, ΔG#et(n) and λet (n = 1–4), respectively, were also calculated in this study for A-1 to A-8 up to D-1 to D-8 in accordance with the Marcus theory.  相似文献   
80.
无义介导的mRNA降解途径(nonsense-mediated mRNA decay,NMD)作为细胞内的一种重要的mRNA质量监控机制,可以降解含有提前终止密码子(premature termination codon,PTC)的异常转录本,从而避免截短蛋白质对细胞的毒害,但其详细的分子机制有待进一步阐释。蓝氏贾第虫(Giardia lamblia)作为一种寄生性单细胞原生动物,进化地位特殊,对其NMD途径的研究有利于阐明基因表达调控的分子和进化机制。本研究通过酵母双杂交及体外pull-down实验分析了贾第虫NMD途径因子上游移码蛋白1(Giardia lamblia up-frameshift 1,GlUPF1)、贾第虫RNA结合蛋白(Giardia lamblia HRP1, GlHRP1)、贾第虫核糖核酸外切酶(Giardia lamblia Ski7p,GlSki7p、Giardia lamblia XRN1,GlXRN1)之间的相互作用关系。结果表明,GlUPF1全长与GlHRP1、GlXRN1(1~500 aa)、GlSki7p间均可发生相互作用。而且GlUPF1的CH结构域和C端结构域分别与GlHRP1、GlXRN1(1~500 aa)、GlSki7p相互作用。说明GlUPF1在贾第虫NMD途径中作为招募平台,在无义mRNA识别和降解过程中发挥重要作用。为此,结合本实验室之前的研究结果,我们提出原生动物贾第虫的NMD途径:在提前终止密码子处SURF(SMG1-UPF1-eRF1-eRF3)复合物形成后,GlUPF1被磷脂酰肌醇3-激酶(suppressor with morphogenetic effect on genitalia 1,SMG1)磷酸化修饰, NMD途径激活,随后GlUPF1与HRP1相互作用,将转录本标记为NMD底物;GlUPF1进而招募下游贾第虫5′-3′核糖核酸降解酶GlXRN1、贾第虫3′-5′ 核糖核酸降解因子GlSki7p,最终降解靶标mRNA。  相似文献   
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