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Type 1 Diabetes Mellitus (T1D) results from the destruction of insulin-producing beta cells in the pancreas by autoreactive T cells. Myeloid derived suppressor cells (MDSCs) are a recently identified immune cell subset that down-regulate T cells. Whether defects in MDSC numbers or function may contribute to T1D pathogenesis is not known. We report here that MDSCs are unexpectedly enriched in peripheral blood of both mice and patients with autoimmune diabetes. Peripheral blood MDSCs from T1D patients suppressed T cell proliferation in a contact-dependent manner; however, suppressive function could be enhanced with in vitro cytokine induction. These findings suggest that native T1D MDSCs are not maximally suppressive and that strategies to promote MDSC suppressive function may be effective in preventing or treating T1D.  相似文献   
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目的探讨锰卟啉(MnTBAP)对大鼠局灶性脑缺血损伤的保护作用及其可能机制。方法采用线拴法建立大鼠大脑中动脉栓塞(MCAO)模型,分为假手术组、缺血组、MnTBAP治疗组。缺血组和治疗组术后立即腹腔注射生理盐水和MnTBAP(10mg/kg体重),缺血24h后处死,用原位末端标记技术(TUNEL)和免疫组织化学方法对缺血侧脑组织神经细胞凋亡和凋亡调控蛋白Caspase-3表达进行检测。结果与假手术组相比,缺血组脑组织神经细胞凋亡及Caspase-3蛋白表达水平明显增加(P<0.01);与缺血组相比,MnTBAP治疗组神经细胞凋亡及Caspase-3蛋白表达水平显著减少。结论 MnTBAP能下调Caspase-3蛋白表达,抑制脑组织神经细胞凋亡,对缺血性脑损伤具有保护作用。  相似文献   
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目的 观察锰苯甲酸卟啉(MnTBAP)对SD大鼠小肝移植物模型缺血再灌注损伤的治疗及保护作用.方法 采用二袖套法建立供肝/标准肝体积比(GV/SV)≤30%的小肝移植物大鼠模型,将大鼠随机分为A:假手术组(n=24),B:对照组(n=24),C:MnTBAP治疗组(n=24),于复流后3、6、12、24 h各取6只处死取材,检测各组大鼠肝组织中肿瘤坏死因子(TNF)-α mRNA表达、髓过氧化物酶(MPO)、丙二醛(MDA)、肝功能指标和肝细胞凋亡间的状态.结果 与假手术组比较,对照组肝组织TNF-α mRNA及MDA、MPO含量显著升高(P<0.01),肝丙氨酸转氨酶(ALT)活性显著升高(P<0.01),肝细胞凋亡明显增多(P<0.01);而MnTBAP治疗组的肝组织MDA、MPO含量较对照组显著降低(P<0.05),肝细胞凋亡减少,且在术后6、12、24 h,肝TNF-α mRNA表达均下降(P<0.05),血清ALT水平也明显降低(P<0.01).结论 MnTBAP可以抑制中性粒细胞的呼吸爆发,降低肝组织TNF-α mRNA表达、减轻细胞膜损伤程度,对缺血肝损伤有良好的保护作用.  相似文献   
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A number of synthetic manganese complexes exhibit both in vitro and in vivo catalytic antioxidant activities. This study reports that the antioxidant potencies of a new series of meso-N,N'-dialkyl-imidazolium substituted manganese(III) porphyrins are dependent, in part, on their ability to redox cycle with endogenous flavin-dependent oxidoreductases. Inhibition of lipid peroxidation activities of these novel cationic porphyrins was compared using rat brain homogenate as a source of lipids and endogenous oxidoreductases. Iron and ascorbate was used as initiators of lipid peroxidation, and two indices of lipid peroxidation (thiobarbituric acid reactive species (TBARS) and F(2)-isoprostanes) were determined. All meso-N,N'-dialkyl-imidazolium substituted porphyrins tested were potent inhibitors of lipid peroxidation with IC(50) ranging from 0.1 to 34 microM with a metal-dependent potency of Mn(III)>Co(III)>Zn(II). A flavin-dependent oxidoreductase antioxidant process was supported by the ability of the diphenyleneiodonium chloride (DPI, a flavoenzyme inhibitor) to decrease the potency of Mn-porphyrins in the lipid peroxidation model and that Mn-porphyrins stimulate NADPH oxidation in rat brain homogenates. These data suggest that metalloporphyrins may have differential antioxidant effects in tissues due to the presence or absence of flavin-dependent oxidoreductases.  相似文献   
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Sensorineural hearing damage is a frequent complication of bacterial meningitis, affecting as many as 30% of survivors of pneumococcal meningitis. There is a substantial body of evidence that oxidants, such as reactive nitrogen species (RNS), are central mediators of brain damage in experimental bacterial meningitis. In the present study, we investigated whether RNS also contribute to the pathophysiology of suppurative labyrinthitis in our well-established rat model of pneumococcal meningitis. In all infected rats, but not in uninfected controls, we observed suppurative labyrinthitis. Cochlear inflammation was accompanied by severe blood-labyrinth barrier (BLB) disruption as evidenced by increased Evans Blue extravasation. Furthermore, increased cochlear expression of endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) was detected by immunohistochemistry. Colocalization of iNOS and tyrosine nitration (a marker of RNS attack) indicated that nitric oxide (NO) produced by iNOS contributes to oxidative cochlear damage through the action of RNS. To determine the pathophysiological role of RNS in BLB disruption, rats were treated with peroxynitrite scavengers (MnTBAP and uric acid, UA). Six h after adjunctive treatment with 300 mg/kg i.p. UA or 15 mg/kg i.p. MnTBAP+100 mg/kg i.p. ceftriaxone, BLB disruption was significantly reduced compared with that in infected animals treated only with ceftriaxone. Therefore, we conclude that RNS are involved in the breaching of the BLB during meningogenic pneumococcal labyrinthitis.  相似文献   
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目的:观察锰四(4-苯甲酸)卟啉[MnTBAP]对大鼠急性放射性肺损伤的保护作用。方法:200~230g SD雄性大鼠分为正常对照组、照射损伤组和MnTBAP治疗组。用6 MV X射线、单次照射全肺28Gy,建立大鼠肺损伤模型。损伤组腹腔注射生理盐水(1.5mL/kg),MnTBAP组腹腔注射MnTBAP(10mg/kg)。经1、4、8和12周,采用ELISA法检测血清转化生长因子β1(TGF-β1)水平;肺组织作病理检查和生化检测超氧化物歧化酶(SOD)、脂质过氧化产物丙二醛(MDA)、羟脯氨酸(Hyp)、抗超氧阴离子自由基(ASAR)。结果:病理检查显示,MnTBAP组肺组织损伤程度较损伤组明显减轻;生化检测结果显示,经1~12周,与照射损伤组相比较,MnTBAP治疗后SOD含量显著增加(P值均<0.001),ASAR含量显著增加(P值均<0.001),MDA含量显著减少(1周,P<0.001;4~12周,P值均<0.05),TGF-β1含量显著减少(P值均<0.001),Hyp含量1~4周没有变化,8~12周明显降低(8周,P<0.05;12周,P<0.01)。结论:MnTBAP具有抗氧化清除自由基功能,对放射性肺损伤具有保护作用,可能是潜在的放射性损伤保护剂。  相似文献   
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Cationic Mn porphyrins are among the most potent SOD mimics and peroxynitrite scavengers. They have been widely and successfully used in different models of oxidative stress and are either progressing towards or are in phase I of clinical trials. The most frequently used compounds are Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+) or AEOL10113), its methyl analogue (MnTM-2-PyP(5+) or AEOL10112), and Mn(III) meso-tetrakis(4-benzoic acid)porphyrin (MnTBAP). A great discrepancy between the in vivo data obtained with Calbiochem preparations and those of authentic MnTE-2-PyP(5+) and MnTM-2-PyP(5+) samples were recently observed. Surprisingly, the commercial samples were invariably of poor identity and consisted of mixtures of nearly equal contributions of non-alkylated, mono-, di-, tri- and tetraalkylated porphyrins, lacking thus the major structural entity that determines their antioxidant potency, i.e., the four positively charged orthoN-alkylpyridyl groups that afford thermodynamic tuning of the active site and electrostatic guidance of anionic superoxide and peroxynitrite species toward the metal center. The MnTE-2-PyP(5+) and MnTM-2-PyP(5+) compounds were not even the major species in the commercial samples sold as "MnTE-2-PyP" and "MnTM-2-PyP", respectively. While we have already reported the insufficient impurity of the MnTBAP samples from Alexis and other suppliers, in one more recent lot the situation is dramatic, as 25% of the sample was not MnTBAP, but metal-free ligand, H(2)TBAP. The (unintentional) use of the Mn porphyrins of low quality compromises therapeutic and/or mechanistic conclusions. Simple techniques, which include thin-layer chromatography, electrospray-mass spectrometry, UV-vis spectroscopy, and electrochemistry described here could be used routinely to check the overall quality of Mn porphyrins in order to avoid misleading conclusions and waste of valuable resources (animals, compounds, time, manpower).  相似文献   
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