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   59篇
  免费   4篇
  2021年   1篇
  2017年   1篇
  2016年   4篇
  2013年   3篇
  2012年   5篇
  2011年   3篇
  2010年   1篇
  2009年   3篇
  2008年   3篇
  2007年   3篇
  2006年   3篇
  2005年   2篇
  2004年   5篇
  2003年   3篇
  2002年   3篇
  2001年   1篇
  2000年   4篇
  1999年   1篇
  1998年   1篇
  1997年   2篇
  1990年   1篇
  1985年   4篇
  1984年   1篇
  1980年   2篇
  1976年   1篇
  1974年   1篇
  1973年   1篇
排序方式: 共有63条查询结果,搜索用时 15 毫秒
1.
To define the role of asymptomatic autoimmune thyroiditis in the cause of breast cancer, the presence of circulating thyroid autoantibodies was studied in two populations, one with a high risk of breast cancer (British women) and one with a low risk (Japanese women). Ostensibly healthy women and patients with breast cancer from both countries were studied. There was no difference in the incidence of thyroid autoantibodies between women with breast cancer and healthy women in either race. The incidence of thyroid autoantibodies in healthy British women, however, was two to three times that in healthy Japanese women. The incidence of reticulin antibodies, was considerably higher in both groups of Japanese women. No remarkable differences in the incidence of antinuclear, smooth-muscle, antimitochondrial, gastric parietal cell, or liver-kidney microsomal antibodies were found between women with breast cancer and healthy women or between the two races. Only the incidence of antinuclear antibodies was marginally higher in Japanese patients with advanced cancer. These results indicate that asymptomatic autoimmune thyroid disease is more prevalent among British than among Japanese women, but they fail to provide direct evidence that autoimmune thyroid disease is associated with breast cancer. Prospective studies of women with autoimmune thyroiditis and studies of young women from low-risk and high-risk populations are needed.  相似文献   
2.
Abstract

Fusarium induced-stress-protein (FISP) of ~51 kDa molecular mass was detected in seven day old germinated wheat (Triticum aestivum var Sonalika) seedlings infected with F. oxysporum for a period of seven days. This particular stress protein (FISP) of ~51 kDa was over-expressed in the case of Fusarium infected seedlings compared to the untreated seedlings where the presence of this protein was insignificant. Localisation of this ~51 kDa protein in root tissue by anti-CSAP (Cadmium Stress Associated Protein) antiserum showed a significantly higher number of gold particles in the case of Fusarium infected root tissue compared to the untreated control. A unique type of organised localisation of FISP around the plasma membrane and outer vacuolar membrane suggests its defensive role against Fusarium infection that might be a general stress protein against biotic and abiotic stresses.  相似文献   
3.
4.
The effects of a range of salinity (0, 100, 200 and 400 mM NaCl) on growth, ion accumulation, photosynthesis and anatomical changes of leaves were studied in the mangrove, Bruguiera parviflora of the family Rhizophoraceae under hydroponically cultured conditions. The growth rates measured in terms of plant height, fresh and dry weight and leaf area were maximal in culture treated with 100 mM NaCl and decreased at higher concentrations. A significant increase of Na+ content of leaves from 46.01 mmol m-2 in the absence of NaCl to 140.55 mmol m-2 in plants treated with 400 mM NaCl was recorded. The corresponding Cl- contents were 26.92 mmol m-2 and 97.89 mmol m-2. There was no significant alteration of the endogenous level of K+ and Fe2+ in leaves. A drop of Ca2+ and Mg2+ content of leaves upon salt accumulation suggests increasing membrane stability and decreased chlorophyll content respectively. Total chlorophyll content decreased from 83.44 g cm-2 in untreated plants to 46.56 g cm-2 in plants treated with 400 mM NaCl, suggesting that NaCl has a limiting effect on photochemistry that ultimately affects photosynthesis by inhibiting chlorophyll synthesis (ca. 50% loss in chlorophyll). Light-saturated rates of photosynthesis decreased by 22% in plants treated with 400 mM NaCl compared with untreated plants. Both mesophyll and stomatal conductance by CO2 diffusion decreased linearly in leaves with increasing salt concentration. Stomatal and mesophyll conductance decreased by 49% and 52% respectively after 45 days in 400 mM NaCl compared with conductance in the absence of NaCl. Scanning electron microscope study revealed a decreased stomatal pore area (63%) in plants treated with 400 mM NaCl compared with untreated plants, which might be responsible for decreased stomatal conductance. Epidermal and mesophyll thickness and intercellular spaces decreased significantly in leaves after treatment with 400 mM NaCl compared with untreated leaves. These changes in mesophyll anatomy might have accounted for the decreased mesophyll conductance. We conclude that high salinity reduces photosynthesis in leaves of B. parviflora, primarily by reducing diffusion of CO2 to the chloroplast, both by stomatal closure and by changes in mesophyll structure, which decreased the conductance to CO2 within the leaf, as well as by affecting the photochemistry of the leaves.  相似文献   
5.
Mittra B  Ray DS 《Eukaryotic cell》2004,3(5):1185-1197
Crithidia fasciculata cycling sequence binding proteins (CSBP) have been shown to bind with high specificity to sequence elements present in several mRNAs that accumulate periodically during the cell cycle. The first described CSBP has subunits of 35.6 (CSBPA) and 42 kDa (CSBPB). A second distinct binding protein termed CSBP II has been purified from CSBPA null mutant cells, lacking both CSBPA and CSBPB proteins, and contains three major polypeptides with predicted molecular masses of 63, 44.5, and 33 kDa. Polypeptides of identical size were radiolabeled in UV cross-linking assays performed with purified CSBP II and 32P-labeled RNA probes containing six copies of the cycling sequence. The CSBP II binding activity was found to cycle in parallel with target mRNA levels during progression through the cell cycle. We have cloned genes encoding these three CSBP II proteins, termed RBP63, RBP45, and RBP33, and characterized their binding properties. The RBP63 protein is a member of the poly(A) binding protein family. Homologs of RBP45 and RBP33 proteins were found only among the kinetoplastids. Both RBP45 and RBP33 proteins and their homologs have a conserved carboxy-terminal half that contains a PSP1-like domain. All three CSBP II proteins show specificity for binding the wild-type cycling sequence in vitro. RBP45 and RBP33 are phosphoproteins, and RBP45 has been found to bind in vivo specifically to target mRNA containing cycling sequences. The levels of phosphorylation of both RBP45 and RBP33 were found to cycle during the cell cycle.  相似文献   
6.
7.
Whole body Co60 gamma radiation induced changes in lactic dehydrogenase (LDH) activity, pyruvate, lactate content and rate of oxygen (O2) consumption in a tropical hibernating anuran (Bufo melanostictus). In 3.5 and 7 Gy treated groups, a significant increase in LDH activity and lactate/pyruvate ratio was observed, whereas a significant decrease in O2 consumption rate was observed in treated animals on post-irradiation day (PID) 1, 5 and 10. Increase in LDH activity was observed on PID-1 in both the treated groups, reached to a peak on PID-5 in 7 Gy treated group and then declined on PID-10.  相似文献   
8.
Plant root mucilage is known to enhance soil quality by contributing towards the soil carbon pool, soil aggregation, detoxification of heavy metal ions and interactions with rhizospheric microflora. Mucilage consists of many monosaccharide units, including fucose which can be used as an indicator for plant root based polysaccharides. This is the first report of an immunological technique developed to use anti-fucose antibodies as markers for probing and localizing fucosyl residues in mucilage polysaccharide and, in turn, for localization of plant root mucilage. Fucose was complexed with bovine serum albumin to raise antibodies against fucose. A fucose-directed antibody was shown to cross-react with root cap mucilages from grasses. This antibody was used to localize root mucilage polysaccharide in maize and wheat root caps using immunogold electron microscopy. Abundant labelling could be localized on the cell wall, and in the intercellular matrix and vesicles of the peripheral root cap cells. Labelling was less intense in cells towards the centre of the root cap tissue. Control experiments confirmed that immunogold localization of fucose was specific and reliable.  相似文献   
9.
Timing of surgery during the menstrual cycle and prognosis of breast cancer   总被引:4,自引:0,他引:4  
There are conflicting reports on the differential effect of surgery performed during the two phases of the menstrual cycle, namely, follicular and luteal, and prognosis of operable breast cancer. A statistical meta-analysis of the published evidence suggests a modest survival benefit of 15+/-4% when the operation is performed during the luteal phase. Further research in this area might provide a novel avenue to understand the natural history of breast cancer. A spin off from these studies might be the understanding of the importance of events that occur at the time of surgery in determining long term prognosis.  相似文献   
10.
BACKGROUND: Plant-derived flavonoids, which occur abundantly in our daily dietary intake, possess antitumor, antibacterial, and free radical scavenging properties. They form active constituents of a number of herbal and traditional medicines. Several flavonoids have been shown to exert their action by interacting with DNA topoisomerases and promoting site-specific DNA cleavage. Therefore, flavonoids are potential candidates in drug design. We report here that, although the flavonoids luteolin and quercetin are potent antileishmanial agents, luteolin has great promise for acting as a lead compound in the chemotherapy of leishmaniasis, a major concern in developing countries. MATERIALS AND METHODS: Kinetoplast DNA (kDNA) minicircle cleavage in drug-treated parasites was measured by electrophoresis of the total cellular DNA, followed by Southern hybridization using 32P labeled kDNA as a probe. Cell cycle progression and apoptosis were measured by flow cytometry using propidium iodide and fluorescein isothiocyanate (FITC)-labeled Annexin V. RESULTS: Luteolin and quercetin inhibited the growth of Leishmania donovani promastigotes and amastigotes in vitro, inhibited DNA synthesis in promastigotes, and promoted topoisomerase-II-mediated linearization of kDNA minicircles. The IC50 values of luteolin and quercetin were 12.5 microM and 45.5 microM, respectively. These compounds arrest cell cycle progression in L. donovani promastigotes, leading to apoptosis. Luteolin has no effect on normal human T-cell blasts. Both luteolin and quercetin reduced splenic parasite burden in animal models. CONCLUSION: Luteolin and quercetin are effective antileishmanial agents. Quercetin has nonspecific effects on normal human T cells, but luteolin appears nontoxic. So, luteolin can be a strong candidate for antileishmanial drug design.  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