首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   61篇
  免费   3篇
  国内免费   4篇
  2023年   1篇
  2021年   5篇
  2020年   2篇
  2019年   1篇
  2018年   2篇
  2017年   3篇
  2016年   1篇
  2015年   6篇
  2014年   3篇
  2013年   4篇
  2012年   10篇
  2011年   6篇
  2010年   3篇
  2009年   2篇
  2007年   2篇
  2006年   3篇
  2005年   3篇
  2004年   2篇
  2003年   3篇
  2001年   1篇
  1999年   4篇
  1995年   1篇
排序方式: 共有68条查询结果,搜索用时 15 毫秒
1.
Activated hepatic stellate cells promote hepatocellular carcinoma (HCC) progression. Hepatic stellate cells play a key role in retinoid metabolism, and activation of stellate cells increases retinoic acid (RA) in the liver. However, the role of RA in HCC proliferation remains unclear. We aimed to analyse the mechanism of RA in HCC proliferation. Thirty-eight patients who had undergone hepatic resection for HCCs were recruited. Paired non-tumour tissues, adjacent and distal to HCCs, were collected, and the RA levels in the tissues were analysed. The mechanisms of RA and HCC proliferation were assessed in liver cancer cell lines by protein and gene expression analyses. Early recurrence of HCC was significantly higher in patients with a higher RA concentration than in those with a lower RA concentration in tissues adjacent to HCCs (61.1% vs. 20%, p = .010). RA promoted HCC cell proliferation and activated the expression of Amphiregulin, a growth factor in hepatocarcinogenesis. The promoter of Amphiregulin contained the binding sites of the RA receptor, RXRα. Wnt signalling also activated the expression of Amphiregulin, and the RA and Wnt pathways acted synergistically to increase the expression of Amphiregulin. Furthermore, RXRα interacted with β-catenin and then translocated to the nucleus to activate Amphiregulin. An increased RA concentration in the tissues adjacent to the tumour was associated with an early recurrence of HCC. RA activated the expression of Amphiregulin, and then promoted HCC proliferation, which might partly contribute to early recurrence of HCC after hepatic resection.  相似文献   
2.
目的 抑郁的发生机制不清及药物的临床疗效不佳,导致其成为世界难题。已有研究发现甲醛的气态暴露或液态腹腔注射都可直接诱发小鼠抑郁样行为,而内源甲醛是否参与抑郁的发生尚不清楚。本研究探索脂多糖(lipopolysaccharide,LPS)是否通过刺激内源甲醛产生而诱发小鼠抑郁的分子机制;并观察非侵入物理疗法——630 nm红光照射是否能激活甲醛脱氢酶而降解甲醛,从而改善小鼠抑郁样行为。方法 雄性成年C57BL/6J小鼠随机分组:a.对照组,腹腔注射磷酸缓冲液(phosphate buffer solution,PBS);b.抑郁模型组,按浓度梯度腹腔注射LPS;c.红光干预组,按浓度梯度腹腔注射LPS后并定时进行630 nm全身红光照射。采用旷场实验(open field test,OFT)、糖水偏爱(suorose preference test,SPT)、悬尾实验(tail suspension test,TST)、强迫游泳(forced swimming test,FST)等方法,评估小鼠的抑郁样行为;用甲醛荧光(Na-FA,特异甲醛荧光探针)定量法及整脑甲醛荧光成像法,检测小鼠脑...  相似文献   
3.
Molecular Biology Reports - Ailanthus altissima Swingle, is a tree species native to East Asia and has a great potential in decorative, bioenergy and industrial applications in many countries. To...  相似文献   
4.
5.
6.
Ceratopteris thalictroides (L.) Brongn. (Parkeriaceae) is a difficult fern species to taxonomically classify. Three cryptic species were revealed in the previous studies, referred to as the north type, the south type, and the third type. Because much of the distribution range of C. thalictroides in China was not included in the sampling of the previous studies, the taxonomic complexity of C. thalictroides in China remained uncertain. In order to identify the uncharacterized cryptic species, we examined four chloroplast DNA (cpDNA) non-coding regions and compared sequence variation within this species complex. Sequence data were obtained from 143 individuals in 24 populations throughout the natural distribution of the species in China. Nineteen haplotypes were identified. Molecular systematic and phylogeographical analyses revealed two genetically distinct clusters of cpDNA haplotypes in China. One cluster included haplotypes associated with the north type, and another with the south type cryptic species. The N ST value was significantly higher than the G ST value (N ST = 0.768 > G ST = 0.434, P < 0.05), indicating the presence of a significant phylogeographical structure of C. thalictroides in China. The results of AMOVA analysis showed a significant inter-group differentiation (F ST = 0.918; P < 0.001). Analyses based on different, but complementary methods suggest that in China, C. thalictroides contains only two of the cryptic species (the north and south types). Two haplotypes, H8 and H17, of the interior node in the minimum-spanning network (MSN) of cpDNA haplotypes are widespread. The origin of the widespread haplotypes in China may have resulted from long-distance dispersal to China.  相似文献   
7.
We have previously shown that invariant Vα19-Jα33 TCR(+) (Vα19i T) cells suppress the disease progress in some models for organ specific autoimmune diseases and type IV allergy that deteriorate along with decline to excess in Th1- or Th17- immunity. In this study, we examined the effects of over-generation of Vα19i T cells on the Th2-controlled immunoglobulin isotype production in the models for type I allergy. IgE production by invariant Vα19-Jα33 TCR transgenic (Tg) mice was suppressed compared with that by non-Tg controls following administration with goat anti-mouse IgD antiserum or OVA, while IgG2a production was not influenced by the introduction of the transgene into the recipients. IgE production by wild type mice was similarly reduced when they were subjected to adoptive transfer with invariant Vα19-Jα33 TCR Tg(+) but not Tg(-) cells prior to immunization. Furthermore, the suppression of IgE production by these recipients was enhanced when they were previously administered with a Vα19i T cell activator, one of the modified α-mannosyl ceramides. In summary, it is suggested that Vα19i T cells have potential to participate in the homeostasis of immunity and that they suppress disease progression resulting from not only Th1- but also Th2- immunity excess.  相似文献   
8.
9.
土耳其斯坦叶螨Tetranychus turkestani(Vgorag et Nikolski)是新疆棉花害螨的优势种,本试验通过调查土耳其斯坦叶螨对棉田为害程度,研究了土耳其斯坦叶螨对新疆主栽的6个棉花品种(系)的种群动态进行了比较:新海21号、新陆早26号2个棉花品种上叶螨密度水平较低,标杂A1、297-5、81-3、新陆早12号叶螨密度没有显著差异.在此基础上比较了6种品种(系)上土耳其斯坦叶螨的实验种群参数:土耳其斯坦叶螨在新海21号、新陆早12号、新陆早26号品种上各虫态发育历期较长,各虫态存活率较低,每雌产卵量较少,种群趋势指数较低;而在标杂A1、297-5、81-3品种上的发育历期较短,各虫态存活率较高,每雌产卵量较多,种群趋势指数也较高.  相似文献   
10.
Astrocytes, the major glial population in the central nervous system (CNS), play an important role in neuronal homeostasis, neurogenesis, and synaptogenesis. The cells have a stellate shape with elaborated processes in the developing CNS. Cultured astrocytes become stellate when the cells undergo differentiation in response to stimuli. Nevertheless, the molecular mechanism for astrocytic stellation is poorly understood. Here, we showed that the addition of serum induced a flat polygonal shape in cultured astrocytes with a reduced level of Mps one binder 2 (Mob2) that is involved in neurite growth by forming stable complex with a nuclear Ser/Thr kinase Dbf2-related protein kinase 1 (NDR1). Furthermore, exposure to a membrane permeable cAMP analogue, dbcAMP, not only induced astrocytic stellation, but also caused an increase in Mob2 expression. Similarly, the upregulation of Mob2 mRNA expression was induced by exposure of astrocytes to pituitary adenylyl cyclase-activating polypeptide (PACAP). Pretreatment with a cAMP/protein kinase A (PKA) inhibitor, KT-5720, significantly blocked the effect of dbcAMP and PACAP on induced upregulation of Mob2 mRNA expression in astrocytes. In addition, the process withdrawal of dbcAMP-treated astrocytes was caused by the inhibition of Mob2 expression using lentivirus-mediated Mob2 shRNA delivery system. Based on our findings, we suggest that Mob2 is involved in PKA signaling-mediated astrocytic stellation.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号