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   50篇
  免费   0篇
  2019年   6篇
  2018年   2篇
  2014年   1篇
  2009年   2篇
  2008年   6篇
  2007年   5篇
  2006年   2篇
  2005年   2篇
  2004年   2篇
  2002年   3篇
  2001年   1篇
  2000年   3篇
  1999年   2篇
  1998年   2篇
  1996年   1篇
  1995年   1篇
  1994年   2篇
  1993年   3篇
  1990年   1篇
  1989年   1篇
  1976年   1篇
  1973年   1篇
排序方式: 共有50条查询结果,搜索用时 203 毫秒
11.
12.
短蛸外套膜和足粘液细胞的类型及分布   总被引:11,自引:0,他引:11  
采用阿新兰与过碘酸雪夫氏反应(AB-PAS)染色法对短蛸(Octopusocellatus)外套膜和足各部位粘液细胞进行分类及分析。将粘液细胞分为Ⅰ~Ⅳ4种类型:分别呈红色、蓝色、紫红色和蓝紫色。胴体部背面和腹面的外套膜外表皮均有4种粘液细胞,以Ⅲ型和Ⅳ型粘液细胞为主,背面粘液细胞密度较小,腹面的密度较大。腕上皮皱褶处粘液细胞密度较大,其他大部分区域粘液细胞密度较小,以Ⅱ型为主,另有少量Ⅲ型和Ⅳ型粘液细胞;吸盘外上皮含有大量的粘液细胞,也以Ⅱ型为主。漏斗内外上皮粘液细胞密度较大,基部以Ⅱ型为主,其他部位则以Ⅲ型为主。通过对各部位粘液细胞的分类和比较,可以看出粘液细胞的分布和类型与其所在部位执行的功能有密切的联系。  相似文献   
13.
RNA interference is a powerful tool for the functional analysis of proteins by specific gene knockdown. In this study, we devised a rapid and efficient way to screen suitable siRNA sequences and subsequently employ them for specific gene knockdown in usually hard-to-transfect lymphoid cell lines, using a self-inactivating lentiviral vector. Two proteins with different half-lives were chosen, cyclin D1 and STAT3. A specific lacZ reporter fusion assay was used to identify highly effective siRNA sequences. Only siRNA molecules with more than 85% of knockdown efficiency were selected for the generation of lentiviral transfer vectors. Transduction rates of 75–99% were achieved in the lymphoma cell lines Granta 519 (mantle cell lymphoma), Karpas 299, and SUDHL-1 (anaplastic large T cell lymphoma), as demonstrated by green fluorescent protein expression in fluorescence-activated cell sorting analysis. The high level of transduction efficiency allows RNA interference studies to be performed on transduced cells without further manipulation, such as cell sorting or cloning. The LacZ reporter system together with the lentivirus technology is a very important tool in the hematology field, which enables experiments in lymphoid cells that were not possible before.

Electronic supplementary material

The online version of this article (doi:10.1007/s12308-008-0020-x) contains supplementary material, which is available to authorized users.  相似文献   
14.
Mantle cell lymphoma (MCL) has a heterogeneous clinical course and is mainly an aggressive B cell non-Hodgkin lymphoma; however, there are some indolent cases The Ki-67 index, defined by the percentage of Ki-67-positive lymphoma cells on histopathological slides, has been shown to be a very powerful prognostic biomarker. The pathology panel of the European MCL Network evaluated methods to assess the Ki-67 index including stringent counting, digital image analysis, and estimation by eyeballing. Counting of 2 × 500 lymphoma cells is the gold standard to assess the Ki-67 index since this value has been shown to predict survival in prospective randomized trials of the European MCL Network. Estimation by eyeballing and digital image analysis showed a poor concordance with the gold standard (concordance correlation coefficients [CCC] between 0.29 and 0.61 for eyeballing and CCC of 0.24 and 0.37 for two methods of digital image analysis, respectively). Counting a reduced number of lymphoma cells (2 × 100 cells) showed high interobserver agreement (CCC = 0.74). Pitfalls of the Ki-67 index are discussed and guidelines and recommendations for assessing the Ki-67 index in MCL are given.  相似文献   
15.
Tilia platyphyllos Scop. plantlets were inoculated in vitro with five Tuber borchii Vittad. strains (1BO, 17BO, 43BO, 71BO and 10RA) to test their intraspecific variability. The ability of the strains to form mycorrhizas varied, with the mean degree of ectomycorrhizal infection ranging from 50.6% (for 1BO) to 82.1% (for 10RA). The anatomical/morphological characteristics of the resulting mycorrhizas were determined. Although the morphological features of the mycorrhizas and the characteristics of the cystidia were similar for all strains tested, differences were found in the anatomical features of the mantle. The form of the mantle cells was examined in the surface and inner layers (6 and 12 μm deep, respectively) by both conventional and confocal microscopy. These cells were polygonal in 1BO, and 71BO, epidermoid in 43BO and intermediate in 17BO and 10RA. The structure of the mantle also varied and thus provided little information with which to identify T. borchii mycorrhizas. Accepted: 7 July 2000  相似文献   
16.
Laboratory friendly, cryopreservation procedures with respect to cryopreservation formulations and cryopreservation temperatures were attempted, in the present study to ensure perennial availability of cultured mantle cells of bivalve (Paphia malabarica). Screening of cryopreservative formulations with different concentrations of DMSO, Propylene glycol and Glycerol was carried out for cryopreservation of freshly dissociated cells of Paphia malabarica. Out of these cryopreservative formulations, 10% DMSO, 10% Propylene glycol and 15% Glycerol were selected for cryopreservation of the mantle cells pooled from 1-day old primary culture and cell line after 3 passages at the end of different cryopreservation periods. Cryopreservative formulation with 15% glycerol, served as a best cryoprotectant for the cryopreservation of cells sourced from freshly dissociated cells as well as from primary cultures and cell cultures after three passages of mantle cells of Paphia malabarica, retaining metabolic activity of resurrected cells. Both, cell cultures established from uncryopreserved cells as well as cryopreserved cells showed similar alkaline phosphatase and carbonic anhydrase activities thus indicating retention of their biomineralization capacity even after cryopreservation at low and ultralow temperatures.  相似文献   
17.
The complete amino acid sequence of squid Todarodes pacificus troponin C (TnC), which was shown to bind only 1 mol Ca2+/mol, was determined by both the Edman and cDNA methods. The squid TnC is composed of 147 amino acids including an unblocked Pro at the N-terminus and the calculated molecular weight is 17 003.9. Among the four potential Ca2+-binding sites, namely sites I–IV from the N-terminus, only site IV completely satisfied the consensus amino acid sequence for the active Ca2+-binding loop. This indicates that squid TnC possesses a single Ca2+-binding site at the site IV as scallop TnCs [Nishita et al., J. Biol. Chem. 269 (1994) 3464–3468; Ojima et al., Arch. Biochem. Biophys. 311 (1994) 272–276). The sequence homology of squid TnC to TnCs of scallop, arthropods, and rabbit was 61%, 31–38%, and 31%, respectively. In the sequence of the central D/E-helix region of squid and scallop TnCs, a deletion of three amino acids was required to maximize the homology with the other TnCs.  相似文献   
18.
Mantle cell lymphoma (MCL) is characterized by the translocation t(11;14) (q13;q32), resulting in the overexpression of cyclin-D1. The progression of MCL is an interaction of multitarget and multilink regulation. It has been proven that Bruton’s tyrosine kinase (BTK) is commonly overexpressed in MCL, which makes it a focus of targeted therapy for MCL. Irreversible inhibitors usually have great potency, rapid onset of inhibition and long duration of drug action. Herein, structural modification via an open-loop strategy based on lead compound ibrutinib (IBN) was performed, leading to a series of pyrazole derivatives. Compounds 19c, 19′c, 21c and 21′c showed potent effect in MCL cells with IC50 values lower than 1?μM, and a more than 3-28-fold increase in antiproliferative activity compared with IBN.  相似文献   
19.
不同pH值对三角帆蚌珍珠质分泌的影响   总被引:14,自引:0,他引:14  
邱安东  石安静 《动物学报》1999,45(4):361-370
运用多种组织化学方法和透射电镜技术,研究了5种pH水环境(pH5、6、7、8、9)对三角帆砷外套膜珍珠质分泌的影响机制,结果表明,在中性水环境中,贝体能积极地从外界水环境中吸收钙,并能旺盛地合成和分泌贝壳珍珠层及珍珠有机基质前体物质,持续的酸性水环境导致贝体的钙严重丢失,并引起珍珠质分泌细胞对有机基质前体物质的合成和分泌能力减弱,持续的碱性水环境虽能导致贝体对钙的积累,但珍珠质分泌细胞合成和分泌珍  相似文献   
20.
Earlier work found cuttlefish (Sepia officinalis) ventilatory muscle tissue to progressively switch to an anaerobic mode of energy production at critical temperatures (T c) of 7.0 and 26.8°C. These findings suggested that oxygen availability limits thermal tolerance. The present study was designed to elucidate whether it is the ventilatory apparatus that sets critical temperature thresholds during acute thermal stress. Routine metabolic rate (rmr) rose exponentially between 11 and 23°C, while below (8°C) and above (26°C) this temperature range, rmr was significantly depressed. Ventilation frequency (f V) and mean mantle cavity pressure (MMP) followed an exponential relationship within the entire investigated temperature range (8–26°C). Oxygen extraction from the ventilatory current (EO2) decreased in a sigmoidal fashion with temperature, falling from > 90% at 8°C to 32% at 26°C. Consequently, ventilatory minute volume (MVV) increased by a factor of 20 from 7 to 150% body weight min−1 in the same temperature interval. Increases in MMP and MVV resulted in ventilatory muscle power output (P out) increasing by a factor of > 80 from 0.03 to 2.4 mW kg−1 animal. Nonetheless, costs for ventilatory mechanics remain below 1.5% rmr in the natural thermal window of the population (English Channel, 9–17°C), owing to very low MMPs of < 0.05 kPa driving the ventilatory stream, and may maximally rise to 8.6% rmr at 26°C. Model calculations suggest that the ventilatory system can maintain high arterial PO2 values of > 14 kPa over the entire temperature interval. We therefore conclude that the cuttlefish ventilation system is probably not limiting oxygen transfer during acute thermal stress. Depression of rmr, well before critical temperatures are being reached, is likely caused by circulatory capacity limitations and not by fatigue of ventilatory muscle fibres.  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