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991.
目的 观察脾虚患者胃粘膜超氧化物歧化酶(SOD)活性与前列腺素(PG)的关系。 方法 72例慢性胃病住院患者,按中医辨证分成脾虚组和肝气犯胃组,分别测出胃粘膜SOD活性,以及前列腺素和血栓素A_2的代谢产物6-酮-PGF_(1a)和血栓素B_2(TXB_2)的含量,分析SOD与6-酮-PGF_(1a)和TXB_2的相关性。 结果 脾虚组患者胃粘膜SOD活性为2.7±1.1 U/mg湿重,明显低于肝气犯胃组的4.2±1.7 U/mg湿重(P<0.01);脾虚组胃粘膜6-酮-PGF_(1a)含量为115.7±60.7 pg/mg湿重,亦明显低于肝气犯胃组的289.6±154.2 pg/mg湿重(P<0.01)。SOD活性与6-酮-PGF_(1a)含量呈线性正相关(P<0.05)。 结论 脾虚证患者胃粘膜内自由基代谢紊乱,表现为SOD活性及抗氧化能力低下,并且与胃粘膜PG代谢的改变存在着一定的关系。 相似文献
992.
Sidiropoulos PI Hatemi G Song IH Avouac J Collantes E Hamuryudan V Herold M Kvien TK Mielants H Mendoza JM Olivieri I Østergaard M Schachna L Sieper J Boumpas DT Dougados M 《Rheumatology (Oxford, England)》2008,47(3):355-361
Objective. Recommendations and/or guidelines represent a popularway of integrating evidence-based medicine into clinical practice.The 3E Initiatives is a multi-national effort to develop recommendationsfor the management of rheumatic diseases, which involves a largenumber of experts combined with practising rheumatologists addressingspecific questions relevant to clinical practice. Methods. Ten countries participated in three rounds of discussionsand votes concerning the management of AS. A set of nine questionswas formulated in the domains of diagnosis, monitoring and treatment,after a Delphi procedure. A literature search in MedLine wasconducted. Predefined outcome parameters for the domains ofdiagnosis, monitoring and treatment were assessed. The evidenceto support each proposition was evaluated and scored. Afterdiscussion and votes, the final recommendations were presentedusing brief statements by each national group, following whichthe final international recommendations were formulated. Results. A total of 2699 papers were found and 467 were selectedfor analysis. Twelve key recommendations were developed: threein the domain of diagnosis addressing general diagnostic considerations,early AS diagnosis and general practitioners referralrecommendations; three concerning monitoring of AS disease activity,severity and prognosis; six concerning pharmacological treatment(except biologics): non-steroidal anti-inflammatory drugs/COX-IIinhibitors, bisphosphonates and treatment of enthesitis. Thecompiled agreement among experts ranged from 72% to 93%. Conclusion. Recommendations for the management of AS were developedusing an evidence-based approach followed by expert/physicianconsensus with high level of agreement. Involvement of a largerand more representative group of rheumatologists may improvetheir dissemination and implementation in daily clinical practice. KEY WORDS: Ankylosing spondylitis, Systemic literature search, Recommendations, Non-steroidal anti-inflammatory drugs, COX-II inhibitors, Monitoring, Diagnosis, Treatment 相似文献
993.
茶树籽对钉螺生殖腺和肝脏的影响 总被引:8,自引:0,他引:8
目的 :了解钉螺组织经茶树籽处理的影响。方法 :应用电镜技术观察处理后的钉螺肝脏及生殖腺组织的超微结构。结果 :钉螺在茶树籽作用 2 4 h后 ,肝内细胞受损。雄性生殖细胞有凝固性及溶解性变化 ;成熟精子细胞膜肿胀与内部结构分离 ,线粒体鞘呈现凝集型 ,支持细胞可见凝固性改变 ,且彼此断裂并与生殖细胞分离。雌性钉螺生殖腺可见卵细胞肿胀 ,严重时滤泡细胞有破裂 ,卵细胞膜则可丧失完整性。结论 :茶树籽能损伤钉螺的生殖腺和肝脏。 相似文献
994.
Ming Zhou Haomin Song Xingyu Xu Alireza Shahsafi Yurui Qu Zhenyang Xia Zhenqiang Ma Mikhail A. Kats Jia Zhu Boon S. Ooi Qiaoqiang Gan Zongfu Yu 《Proceedings of the National Academy of Sciences of the United States of America》2021,118(14)
A radiative vapor condenser sheds heat in the form of infrared radiation and cools itself to below the ambient air temperature to produce liquid water from vapor. This effect has been known for centuries, and is exploited by some insects to survive in dry deserts. Humans have also been using radiative condensation for dew collection. However, all existing radiative vapor condensers must operate during the nighttime. Here, we develop daytime radiative condensers that continue to operate 24 h a day. These daytime radiative condensers can produce water from vapor under direct sunlight, without active consumption of energy. Combined with traditional passive cooling via convection and conduction, radiative cooling can substantially increase the performance of passive vapor condensation, which can be used for passive water extraction and purification technologies.Energy and clean water are global challenges that are intertwined in an unfavorable way: even in areas where water is abundant, energy may not be available to purify it for human use (1, 2). There has been strong interest in developing passive technologies to purify or harvest water without using fuel or electricity. In this context, passive vapor condensation becomes particularly important because many passive water technologies go through the vapor phase of water in their harvesting or purification processes.Traditional vapor condensation technique is based on convective and conductive heat exchange with ambient environments. This technique is widely used in systems with hot vapors (3–6). However, with ever-increasing emphasis on passive systems, there are many situations in which warm- or even room-temperature vapor needs to be effectively condensed, such as extracting water from atmosphere (7–9) and warm vapor generated from high-efficiency solar evaporation (10). For vapor at such temperatures, most traditional condensers fail. For this reason, there is a clear need for a condensation technique to complement traditional condensers.A different technique is based on radiative vapor condensation. Darkling beetles in the Namib desert (11) use this technique to collect water. Their bodies function as a cooling surface by shedding thermal energy through midinfrared (mid-IR) radiation toward a clear nighttime sky, generating dew from humid air. This mechanism is also used by commercial radiative dew condensers (7–9). However, neither Namib beetle nor existing dew condensers can operate in the daytime (7). Those nighttime radiative condensers are incompatible with many emerging water technologies that require 24 h operation or direct access to sunlight.Recently, Fan et al. showed that passive radiative cooling to subambient temperatures can be realized even during the daytime, by integrating a high-efficiency solar reflector with a high-emissivity thermal emitter in the mid-IR atmospheric transparency window (12). Using this work as a basis, here we demonstrate a daytime radiative condenser. Compared to existing radiative vapor condensers (7–9), our condenser can function even in the presence of sunlight, which is essential for integration into passive water-harvesting systems that mainly operate during daytime. 相似文献
995.
996.
Tai YT Dillon M Song W Leiba M Li XF Burger P Lee AI Podar K Hideshima T Rice AG van Abbema A Jesaitis L Caras I Law D Weller E Xie W Richardson P Munshi NC Mathiot C Avet-Loiseau H Afar DE Anderson KC 《Blood》2008,112(4):1329-1337
Currently, no approved monoclonal antibody (mAb) therapies exist for human multiple myeloma (MM). Here we characterized cell surface CS1 as a novel MM antigen and further investigated the potential therapeutic utility of HuLuc63, a humanized anti-CS1 mAb, for treating human MM. CS1 mRNA and protein was highly expressed in CD138-purified primary tumor cells from the majority of MM patients (more than 97%) with low levels of circulating CS1 detectable in MM patient sera, but not in healthy donors. CS1 was expressed at adhesion-promoting uropod membranes of polarized MM cells, and short interfering RNA (siRNA) targeted to CS1 inhibited MM cell adhesion to bone marrow stromal cells (BMSCs). HuLuc63 inhibited MM cell binding to BMSCs and induced antibody-dependent cellular cytotoxicity (ADCC) against MM cells in dose-dependent and CS1-specific manners. HuLuc63 triggered autologous ADCC against primary MM cells resistant to conventional or novel therapies, including bortezomib and HSP90 inhibitor; and pretreatment with conventional or novel anti-MM drugs markedly enhanced HuLuc63-induced MM cell lysis. Administration of HuLuc63 significantly induces tumor regression in multiple xenograft models of human MM. These results thus define the functional significance of CS1 in MM and provide the preclinical rationale for testing HuLuc63 in clinical trials, either alone or in combination. 相似文献
997.
Yongle Chen Brent R. Helliker Xianhui Tang Fang Li Youping Zhou Xin Song 《Proceedings of the National Academy of Sciences of the United States of America》2020,117(52):33345
The hydrogen isotope ratio of water cryogenically extracted from plant stem samples (δ2Hstem_CVD) is routinely used to aid isotope applications that span hydrological, ecological, and paleoclimatological research. However, an increasing number of studies have shown that a key assumption of these applications—that δ2Hstem_CVD is equal to the δ2H of plant source water (δ2Hsource)—is not necessarily met in plants from various habitats. To examine this assumption, we purposedly designed an experimental system to allow independent measurements of δ2Hstem_CVD, δ2Hsource, and δ2H of water transported in xylem conduits (δ2Hxylem) under controlled conditions. Our measurements performed on nine woody plant species from diverse habitats revealed a consistent and significant depletion in δ2Hstem_CVD compared with both δ2Hsource and δ2Hxylem. Meanwhile, no significant discrepancy was observed between δ2Hsource and δ2Hxylem in any of the plants investigated. These results cast significant doubt on the long-standing view that deuterium fractionation occurs during root water uptake and, alternatively, suggest that measurement bias inherent in the cryogenic extraction method is the root cause of δ2Hstem_CVD depletion. We used a rehydration experiment to show that the stem water cryogenic extraction error could originate from a dynamic exchange between organically bound deuterium and liquid water during water extraction. In light of our finding, we suggest caution when partitioning plant water sources and reconstructing past climates using hydrogen isotopes, and carefully propose that the paradigm-shifting phenomenon of ecohydrological separation (“two water worlds”) is underpinned by an extraction artifact.The analysis of the stable isotope ratios of plant source water (δsource) is a powerful tool enabling the elucidation of a range of plant physiological, ecological, and hydrological processes from scales ranging from individual plants to the planet. δsource provides a foundation on which to form isotope signals of transpired water vapor and plant-derived biomarkers (i.e., cellulose and lipids) and thus is of high relevance to studies of terrestrial water fluxes (1, 2) and paleoclimate reconstructions (3, 4). δsource also contains information on the spatial and temporal origins of water used by plants and so is commonly used for investigating plant water uptake patterns under natural conditions (5, 6). Moreover, dual-isotope (δ2H and δ18O) analysis of δsource was critical in formulating the paradigm-shifting “two water worlds” (TWW) hypothesis, whereby ecohydrological separation exists between plant-accessible soil water pools and those recharging streams and groundwater (7, 8).Elucidation of the foregoing processes rest on the assumption that water extracted from plant stems is isotopically identical to water taken up by plant roots. Plant stem water is typically extracted with the cryogenic-vacuum distillation technique; δ generated with this method is hereinafter referred as δstem_CVD (9). For δstem_CVD to be an accurate indicator of δsource (i.e., δstem_CVD = δsource), two prerequisites must be met: 1) isotope change does not occur during root uptake and/or xylem transport of the source water (prerequisite I) and 2) stem water cryogenic extraction is a robust approach toward isotope recovery of xylem water (prerequisite II). The “δstem_CVD = δsource” assumption is generally valid for oxygen isotopes of water, but numerous studies have used hydrogen isotopes to assess source water, and here this assumption has faced scrutiny, as multiple studies have reported significant depletion in δ2Hstem_CVD compared with δ2Hsource in plants from various habitats (10–18).A frequently invoked explanation for the observed δ2Hstem_CVD depletion is a violation of prerequisite I, as it is believed that symplastic uptake of source water into the root xylem can give rise to hydrogen isotope fractionation (10, 11, 13, 19). The available evidence (10, 11) in support of such an explanation is largely peripheral, because direct, unambiguous confirmation of water uptake/transport-related fractionation would require a comparison of deuterium in source water and water transported within xylem conduits (δ2Hxylem). However, this type of comparison is difficult owing to the technical challenges in obtaining targeted measurements of δ2Hxylem in most plants. Intriguingly, in a field-grown riparian tree species (Populus euphratica) in which δ2Hxylem measurement was made possible with the aid of a syringe-aided xylem sap bleeding technique, no significant difference was observed between δ2Hxylem and δ2Hsource (12). This led to the suggestion that, at least for the investigated species, δ2Hstem_CVD depletion arises not from a violation of prerequisite I, but rather from a violation of prerequisite II. The violation of prerequisite II has been deemed possible (12, 17) based on the argument that hydrogen isotope heterogeneity could be present within the bulk stem water (i.e., the outside xylem water may carry a metabolism-induced, more-depleted δ2H signature compared with the xylem water), potentially causing the stem water extraction technique to artifactually underestimate δ2Hxylem.Given the controvertible state of knowledge regarding the mechanism driving δ2Hstem_CVD depletion, it is imperative for us to build a better and more comprehensive understanding of the isotopic relationships among cryogenic extracted bulk stem water, source water, and xylem water in different plants, so as to put the application of the stem water cryogenic extraction technique in diverse fields on firmer ground. In this context, it should be pointed out that the xylem water direct sampling technique (12) is applicable only to a few riparian tree species. Recently, a new method relying on laser-enabled isotope measurement of water vapor in equilibrium with xylem water has demonstrated potential for in situ continuous monitoring of xylem isotope signatures in trees (20, 21); however, the method needs further development before it becomes broadly applicable to different plant types. Thus, a more generally applicable method is needed for determining xylem water signature across diverse plant types.Toward this goal, and capitalizing on the well-recognized mass balance-dictated principle that the isotopic composition of steady-state (SS) plant transpiration is identical to that of the xylem water supplying the plant canopy, we custom-designed a measurement system to enable independent quantification of xylem water isotope composition through isotope measurement of SS plant transpiration. This measurement system conferred the ability to compare values of δstem_CVD, δsource, and δxylem across a number of plant species of varying native habitats. The data allowed us to confirm the common presence of δ2Hstem_CVD depletion across all plant types measured, and also to demonstrate that this phenomenon is caused by cryogenic extraction-associated artifact and not by water uptake/transport-related fractionation. We also performed a rehydration experiment to illustrate that the extraction artifact is unrelated to within-stem isotope heterogeneity as has been recently suggested, but rather is more likely linked to a deuterium-exchange process that occurs dynamically during cryogenic extraction. Using the TWW hypothesis as an example, we further discuss the ramifications for ecological/hydrological queries that rely on accurate isotopic information on plant source/xylem water. 相似文献
998.
999.
目的观察三明治构型大鼠原代肝细胞长期培养的形态学变化,并对其功能进行测定。方法采用改良原位两步法门静脉胶原酶灌注分离单肝细胞,台盼蓝拒染实验观察细胞活力,利用三明治培养构型培养成年大鼠原代肝细胞,倒置显微镜下连续观察肝细胞的形态学变化,定期收集培养细胞上清液,检测所培养肝细胞的分泌及生物转化功能,并与单层胶原培养肝细胞比较。结果平均每个鼠肝可获取(2~3)×108个肝细胞,存活率为(93±3)%;体外肝细胞培养第3天,细胞活力、清蛋白分泌功能恢复到最佳状态;三明治构型培养第7天,地西泮24h代谢量达到最高峰。三明治构型培养的肝细胞形成肝索样结构,并逐渐形成胆小管网络;在培养的21d内,清蛋白分泌、地西泮代谢始终维持较高的水平;肝细胞形态维持可达28d以上。结论三明治构型肝细胞培养体系更接近于肝细胞体内生长环境,肝细胞可在较长时间内保持良好的形态结构和功能。三明治构型不仅可以应用于肝细胞的基础研究,而且为肝细胞移植和生物人工肝治疗肝衰竭奠定了一定的基础。 相似文献
1000.
Zhai S Zhuang Y Song Y Li S Huang D Kang W Li X Liao Q Liu Y Zhao Z Lu Y Sun Y 《Current HIV research》2008,6(4):335-350
To assess the immunodominance patterns of HIV-1-specific cytotoxic T lymphocyte (CTL) responses and the contribution of these responses against the peptides scanning optimal epitopes in chronic infection, we test the HIV-1-specific CTL responses against a panel of 413 overlapping peptides spanning HIV-1 Asian B sequence, including 147 peptides corresponding to optimal clade B epitopes in 49 chronically HIV-1 infected individuals by interferon-gamma Elispot assay. A large variation in the recognition of peptides restricted by the same HLA class I allele is presented. Some epitopes are targeted frequently by individuals while other epitopes restricted by the same allele are rarely recognized in our research. HLA-B35 and HLA-A03 rather than other HLA alleles contribute greatly to total virus-specific CTL responses. Furthermore, there is a significant inverse correlation between the total contribution of HIV-1-specific CTL responses restricted by different HLA alleles to virus-specific immune responses and viral load in the individuals during advanced infection (P=0.002, r=-0.549). The peptides targeted by individuals have significantly lower entropy compared with those not targeted but restricted by the same HLA class I alleles (P<0.05) in 49 individuals infected by HIV-1, especially the advanced infection subgroup (P=0.044). These data demonstrate that the consistent immunodominance patterns of HIV-1-specific CTL responses of Chinese HIV-1 infected individuals and an inverse correlation between the relative contribution of responses restricted by HLA alleles and viral load, which indicates the important protective effect of optimal epitopes against slow disease progression even in advanced infection. 相似文献