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101.
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Feng Qiu Chun‐hua Shi Jun Zheng Yu‐bin Liu 《Journal of biochemical and molecular toxicology》2013,27(7):364-369
This study was conducted to investigate the biological role of periostin in gastric cancer (GC) under hypoxia. Western blot analysis revealed that along with an upregulation of hypoxia‐inducible factor‐1alpha, there was a time‐dependent induction of periostin in MKN‐45 cells under hypoxia (2% O2), increasing by eightfold as compared to normoxic cells. Pretreatment with 30 µM PD98059, an inhibitor of ERK1/2, significantly reduced hypoxia‐stimulated periostin expression (P < 0.01). Periostin knockdown in MKN‐45 cells was achieved by specific small interfering RNA (siRNA). The conditioned medium from periostin siRNA‐transfected MKN‐45 cells induced significantly less (P < 0.01) endothelial tube formation than control siRNA‐transfected cells. Additionally, periostin silencing markedly decreased the mRNA expression and secretion of vascular endothelial growth factor (VEGF) in hypoxic MKN‐45 cells. Thus, our data suggest that periostin is a hypoxia‐response gene and mediates a cross talk between GC and endothelial cells under hypoxia, partially through regulation of the VEGF expression. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:364‐369, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21498 相似文献
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目的研究肝细胞癌和癌旁肝组织中HIF-1α和VEGF表达及其临床意义。方法利用免疫组织化学检测62例肝细胞癌和癌旁肝组织中HIF-1α、VEGF和CD34的表达。结果HCC中HIF-1α和VEGF的阳性率和阳性表达强度均明显高于癌旁肝组织,且两者表达强度呈显著正相关(P<0.01);癌旁肝硬化和非典型增生的肝细胞亦呈HIF-1α强表达;HIF-1α和VEGF的表达强度与HCC分化程度、肿瘤大小及MV密度呈显著正相关。结论HIF-1α在HCC发生发展过程中可能起重要作用,其表达与HCC的某些生物学行为密切相关,检测HCC组织中HIF-1α的表达有可能作为评估预后的重要指标之一。 相似文献
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M. Bernhardt-Römermann T. Kudernatsch J. Pfadenhauer M. Kirchner G. Jakobi A. Fischer 《应用植被学》2007,10(3):399-406
Question: What are the main reasons for changes in the spatial distribution of vegetation types during the last four decades? Location: Isolated small deciduous forest; surrounded by farmland in the northeast of Munich (Germany). Methods: Based on sequential vegetation mapping from the last four decades the spatial development of the vegetation was analysed. Additionally, environmental parameters (soil parameters, PAR, N-deposition) have been analysed to describe the different vegetation types. Results: By linking the vegetation types to environmental parameters, it was possible to identify N-deposition as the most important factor for the changes. In the 1960s to 1980s the replacement of vegetation types adapted to N-poor conditions by N-rich vegetation was very fast. A vegetation type containing species signifying soil impoverishment vanished totally, another vegetation type indicating nutrient poor conditions decreased dramatically. However, since 1985 up to now the decrease of N-poor vegetation types has slowed, but is still ongoing. As a reason for the decreased rate of replacement, we stressed changes in the vertical structure: From 1961 to 1985 both N-deposition as well as changes in vertical vegetation structure seem to be important. Since 1985 up to now only minor changes in vertical structure could be found; changes are mainly due to N-availability. Conclusion: In this paper, the limitations of different methods to detect vegetation changes are discussed. We focus on the potentials of historical vegetation data and vegetation maps. It is shown that valuable information on N-induced vegetation changes can be retrieved from historical vegetation data. 相似文献
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黄芪对急性白血病患者血清黏附分子水平影响的临床研究 总被引:3,自引:0,他引:3
目的:探讨黄芪对急性白血病病人可溶性细胞间黏附分子-1和可溶性血管细胞黏附分子-1水平的影响。方法:64例初治急性白血病患者随机分为化疗组32例和化疗加黄芪组32例,采用酶联免疫吸附测定方法(EuSA法),对治疗前后的血清可溶性细胞间黏附分子-1和可溶性血管细胞黏附分子-1水平进行检测。结果:①与正常组比较,急性白血病病人治疗前后可溶性细胞间黏附分子-1和可溶性血管细胞黏附分子-1水平升高(P<0 05)。②治疗后,化疗加黄芪组与化疗组血清可溶性细胞间黏附分子-1和可溶性血管细胞黏附分子-1水平均下降(P<0 05),化疗加黄芪组下降尤为明显(P<0 05)。结论黄芪可通过降低白血病血清sICAM-1和sVCAM-1水平的而发挥抗肿瘤作用。 相似文献
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对不同苗龄(1-12d)的刺槐(Robinia pseudoacacia L.)幼苗进行观察,比较了其初生维管组织的发育变化。结果表明:根中的初生维管组织借助下胚轴过渡到子叶中,而茎中的初生维管组织与下胚轴中的维管组织仅是简单的连接。这与Esau等认为幼苗的外部形态可以分为根-下胚轴-子叶和上胚轴苗两个系统的观点是一致的。本研究亦证实了可以将刺槐幼苗的外部形态描述为这两个系统,二者的维管组织只是简单的连接,不存在过渡。 相似文献
109.
This paper investigates the greenhouse gas emissions from a Swedish wetland, constructed to decrease nutrient content in sewage
treatment water. To evaluate the effect of the construction in terms of greenhouse gas emissions we carried out ecosystem-atmosphere
flux measurements of CO2, CH4 and N2O using a closed chamber technique. To evaluate the importance of vascular plant species composition to gas emissions we distributed
the measurement plots over the three dominating plant species at the field site, i.e., Typha latifolia, Phragmites australis and Juncus effusus. The fluxes of CO2 (total respiration), CH4 and N2O from vegetated plots ranged from 1.39 to 77.5 (g m−2 day−1), −377 to 1387 and −13.9 to 31.5 (mg m−2 day−1) for CO2, CH4 and N2O, respectively. Presence of vascular plants lead as expected to significantly higher total respiration rates compared with
un-vegetated control plots. Furthermore, we found that the emission rates of N2O and CH4 was affected by presence of vascular plants and tended to be species-specific. We assessed the integrated greenhouse warming
effect of the emissions using a Global Warming Potential over a 100-year horizon (GWP100) and it corresponded to 431 kg CO2 equivalents m−2 day−1. Assuming a 7-month season with conditions similar to the study period this is equal to 90 tonnes of CO2 equivalents annually. N2O emissions were responsible for one third of the estimated total greenhouse forcing. Furthermore, we estimated that the emission
from the forested bog that was the precursor land to Magle constructed wetland amounted to 18.6 tonnes of CO2 equivalents annually. Hence, the constructed wetland has increased annual greenhouse gas emissions by 71.4 tonnes of CO2 equivalents for the whole area. Our findings indicate that management processes in relation to wetland construction projects
must consider the primary function of the wetland in decreasing eutrophication, in relation to other positive aspects on for
instance plant and animal life and recreation as well as possible negative climatic aspects of increased emissions of CH4 and N2O. 相似文献
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Questions: (1) What are the most important abiotic environmental variables influencing succession in central European man‐made habitats? (2) How do these variables interact with one another and with variation in community properties? Location: Central, western and southern parts of the Czech Republic. Habitats included old fields, urban sites, spoil heaps after coal mining, sites at water reservoirs, extracted sand pit and peatland and reclaimed sites in areas deforested by air pollution. Methods: We investigated vegetation patterns on 15 succes‐sional seres, sampled by the same methods. Time of succession over which the data were available ranged from 12 to 76 years. The cover of vascular plant species (in %) was estimated in 5 m × 5 m plots. The relationships between vegetation characteristics (species composition, total cover, cover of woody species, species number and rate of dominant species turnover) and 13 abiotic site factors, including climatic and soil variables, were tested using CCA ordination and regression models. Results: Substratum pH, the only substratum characteristic, and climate were the environmental variables significantly affecting the vegetation patterns in the course of succession. The rate of succession, measured as the turnover of dominant species, was significantly more rapid in lowland than in mountain climates. On alkaline soils, species numbers in succession increased towards warmer climates. However, acid soils prevented any increase in species numbers, regardless of the climate. Surprisingly, forms of nitrogen and contents of C, P and cations did not exhibit any significant effect on the vegetation characteristics studied. Conclusions: Our approach, to compare a number of seres, can contribute not only to our understanding of succession, but also to help restoration projects to predict vegetation change because the crucial environmental variables, as identified by this study, are easy to measure. 相似文献