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   87篇
  免费   5篇
  92篇
  2021年   6篇
  2020年   3篇
  2019年   4篇
  2016年   4篇
  2015年   5篇
  2014年   8篇
  2013年   8篇
  2012年   6篇
  2011年   5篇
  2010年   9篇
  2008年   2篇
  2007年   3篇
  2006年   4篇
  2005年   5篇
  2004年   1篇
  2003年   4篇
  2002年   3篇
  2001年   4篇
  2000年   1篇
  1996年   1篇
  1992年   1篇
  1991年   1篇
  1990年   3篇
  1988年   1篇
排序方式: 共有92条查询结果,搜索用时 15 毫秒
11.
Unfavorable ratios between the number and activation status of effector and suppressor immune cells infiltrating the tumor contribute to resistance of solid tumors to T-cell based therapies. Here, we studied the capacity of FDA and EMA approved recombinant cytokines to manipulate this balance in favor of efficient anti-tumor responses in B16.OVA melanoma bearing C57BL/6 mice. Intratumoral administration of IFN-α2, IFN-γ, TNF-α, and IL-2 significantly enhanced the anti-tumor effect of ovalbumin-specific CD8+ T-cell (OT-I) therapy, whereas GM-CSF increased tumor growth in association with an increase in immunosuppressive cell populations. None of the cytokines augmented tumor trafficking of OT-I cells significantly, but injections of IFN-α2, IFN-γ and IL-2 increased intratumoral cytokine secretion and recruitment of endogenous immune cells capable of stimulating T-cells, such as natural killer and maturated CD11c+ antigen-presenting cells. Moreover, IFN-α2 and IL-2 increased the levels of activated tumor-infiltrating CD8+ T-cells concomitant with reduction in the CD8+ T-cell expression of anergy markers CTLA-4 and PD-1. In conclusion, intratumoral administration of IFN-α2, IFN-γ and IL-2 can lead to immune sensitization of the established tumor, whereas GM-CSF may contribute to tumor-associated immunosuppression. The results described here provide rationale for including local administration of immunostimulatory cytokines into T-cell therapy regimens. One appealing embodiment of this would be vectored delivery which could be advantageous over direct injection of recombinant molecules with regard to efficacy, cost, persistence and convenience.  相似文献   
12.
The aim of the present study was to investigate the existence of aging- and sex-related alterations in the permeability of the blood-brain barrier (BBB) in the rat, by calculating a unidirectional blood-to-brain transfer constant (Ki) for the circulating tracer [14C]-alpha-aminoisobutyric acid. We observed that: a) the permeability of the BBB significantly increased within the frontal and temporo-parietal cortex, hypothalamus and cerebellum in 28-30 week old rats, in comparison with younger animals; b) in several brain areas of female intact rats higher Ki values (even though not significantly different) were calculated at oestrus than at proestrus; c) in 1-week ovariectomized rats there was a marked increase of Ki values at the level of the frontal, temporo-parietal and occipital cortex, cerebellum and brain-stem. One can speculate that aging- and sex-related alterations in the permeability of the BBB reflect respectively changes in brain neurochemical system activity and in plasma steroid hormone levels.  相似文献   
13.
In traditional medicine extracts of polysaccharide-containing plants are widely employed for the treatment of skin and epithelium wounds and of mucous membrane irritation. The extracts of Opuntia ficus-indica cladodes are used in folk medicine for their antiulcer and wound-healing activities. The present study describes the wound-healing potential of two lyophilized polysaccharide extracts obtained from O. ficus-indica (L.) cladodes applied on large full-thickness wounds in the rat. When topically applied for 6 days, polysaccharides with a molecular weight (MW)>10(4)Da from O. ficus-indica cladodes induce a beneficial effect on cutaneous repair in this experimental model; in particular the topical application of O. ficus-indica extracts on skin lesions accelerates the reepithelization and remodelling phases, also by affecting cell-matrix interactions and by modulating laminin deposition. Furthermore, the wound-healing effect is more marked for polysaccharides with a MW ranging 10(4)-10(6)Da than for those with MW>10(6)Da, leading us to suppose that the fine structure of these polysaccharides and thus their particular hygroscopic, rheologic and viscoelastic properties may be essential for the wound-healing promoter activity observed.  相似文献   
14.
The genetic consequences and gene flow of pikeperch (Sander lucioperca) stocking were assessed in three boreal lakes based on admixture model analysis and comparison of the pre- and post-release patterns of genetic variability at 9 DNA microsatellite loci in the recipient populations. In two out of the three cases, the releases of fish from foreign populations caused significant changes in the genetic structure of the recipient population. The largest changes were observed in Lake Ouluj?rvi, where the post-release sample was almost identical to the released Lake Vanajanselk? population, and about 90% of the catch was composed of the released population. The genetic composition of Lake Lohjanj?rvi pikeperch also shifted markedly towards that of the released Lake Vanajanselk? population, and about half of the later catch was of released Vanajanselk? origin. In Lake Vanajanselk?, in contrast, releases of pikeperch from lakes Painio and Averia had only a small impact on the genetic structure of the pikeperch population. These results indicate that the current stocking practices create an effective artificial gene flow that may strongly shape and reduce the genetic differentiation among the remaining native pikeperch populations. A common feature of all three cases was the lack of prior appraisal of the potential genetic and ecological risks in relation to the expected benefits of the release programmes.  相似文献   
15.
16.
Chlorine containing ruthenium bipyridine carbonyl compounds react readily in dilute alkaline solutions under a CO atmosphere affording a poorly soluble and air sensitive product that is suggested to have a polymeric nature. Various analysis methods (MS and TPD) were used in the characterisation of the product. The replacement of the axial chloride ligands in trans(Cl), cis(CO)[Ru(bpy)(CO)2Cl2] and [Ru(bpy)(CO)2Cl]2 is proposed to be the initial step in the polymerisation. The replacement of chlorides in methanolic solution was confirmed by isolating and characterising the dimeric intermediate [Ru(bpy)(CO)2(COOCH3)]2.  相似文献   
17.
Merkel cell carcinoma (MCC) is a rare neuroendocrine carcinoma of the skin. MCCs and some other skin cancers, such as basal cell carcinomas, frequently harbour Merkel cell polyomavirus DNA. The purpose of the study was to investigate the frequency of second cancers following the diagnosis of MCC. We studied the incidence of second primary cancers after the diagnosis of MCC from the files of the Finnish Cancer Registry in 1979–2006. Among the 172 MCC patients identified a total of 34 second primary cancers were detected in 30 individuals after the diagnosis of MCC. Female MCC patients were diagnosed with 25 subsequent cancers (SIR, 2.35; 95% CI, 1.52–3.47; p < 0.001) and male patients with 9 cancers (SIR, 2.32, 95% CI, 1.06–4.40; p < 0.05). The MCC patients had an increased risk for a subsequent cancer (any site) compared to age-, gender- and calendar period-matched general population (standardized incidence ratio [SIR] 2.34; 95% confidence interval [CI], 1.62–3.27). The risks for basal cell carcinoma of the skin (O = 11), SIR, 3.48; 95% CI, 1.74–6.22 and chronic lymphocytic leukemia (O = 2), SIR, 17.9; 95% CI, 2.16–64.6 were significantly elevated. The SIRs for an overall second primary cancer risk did not change markedly with time since the diagnosis of MCC. We conclude that patients diagnosed with MCC have an increased risk for a second cancer. This risk may in part result from shared etiological factors between MCC and other tumour types, such as immunosuppression or possibly Merkel cell polyomavirus infection.  相似文献   
18.
19.
20.
The challenges for successful launching of a profitable phage therapeutic product include intellectual property rights, safety issues, reproducibility, stability and robustness of the product. A successful and marketable product would be a highly purified bacteriophage preparation containing one or several fully characterized phages, accompanied by optimized methods of administration and backed up by properly controlled efficacy and safety studies.  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