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951.
不同浓度乙醇灌流液对蟾蜍离体心脏活动影响的比较分析 总被引:5,自引:1,他引:4
用不同浓度乙醇灌流液灌流蟾蜍离体心脏,观察其对离体心脏心率、心肌收缩力和心输出量的变化。结果显示:心率减慢,但在10 m mol/L 稍有加快( P > 0 .05) ,浓度在20 m m ol/L 以上时减慢才明显( P < 0 .05) ;心肌收缩幅度下降,其表现浓度越大下降越明显( P < 0 .05 ~0 .01) ;心输出量在10 m mol/L、15 m mol/L 时略有增加,超过30 m mol/L 以后心输出量下降,但不明显( P > 0 .05) 。表明乙醇过量有减慢心率和抑制心肌收缩力的作用,而对输出量影响不大。 相似文献
952.
953.
目的 探讨雷公藤甲素抗骨质疏松的作用及机制。方法 建立大鼠老年性骨质疏松模型。40只22月龄雄性SD大鼠随机分为雷公藤甲素(每天15μg/kg腹腔注射)治疗组和生理盐水对照组(每天15μg/kg腹腔注射),连续8周。采用显微CT分析胫骨近端骨松质的骨密度(BMD)和骨显微结构。WB检测成骨相关蛋白表达水平。TRACP-5b染色法测定破骨细胞数,同时检测骨吸收标志物表达水平。结果 显微CT结果显示,雷公藤甲素治疗组大鼠骨密度、骨体积/总体积比值(Bv/Tv)、骨小梁厚度(Tb.Th)、骨小梁数目(Tb.N)、骨小梁间距(Tb.Sp)均显著高于对照组(P<0.05)。两组的成骨相关蛋白表达水平无明显差异,TRACP-5b染色显示雷公藤甲素减少了体内破骨细胞的数量(P<0.05),同时血液骨吸收标志物水平也明显降低(P<0.05)。结论 雷公藤甲素通过抑制破骨细胞生成进而对老年性骨质疏松有保护作用。雷公藤甲素可能是治疗老年性骨质疏松症的一种可行方案。 相似文献
954.
目的 探究Chevron截骨术截骨远端外侧位移距离对外翻足关节接触特征的影响,为临床上选择合适的位移距离提供参考依据。方法 测量踝关节中立位状态下正常足、外翻足及外翻足Chevron截骨术截骨远端分别向外侧位移2.0、4.0、6.0 mm后前足、中足和后足各关节接触力、峰值压强和接触面积,并对结果进行分析。结果 与正常足相比,外翻足第1跖楔关节(t=-3.33, P=0.02)、跟骰关节(t=-2.74, P=0.03)和距下关节(后关节面)(t=-2.89, P=0.03)的接触力显著增高;外翻足距舟关节(t=-2.73, P=0.03)与跟骰关节(t=-2.74, P=0.03)的峰值压强显著增高;行Chevron截骨术后,随着截骨远端向外侧位移距离的增加,外翻足第1跖楔关节和跟骰关节的接触力逐渐减小;外翻足距舟关节和跟骰关节的峰值压强逐渐减小。结论 中度外翻足行Chevron截骨术后,当第1跖骨截骨远端向外侧位移6 mm时能有效恢复部分关节间力的分布,且能缓解部分关节局部应力集中现象。 相似文献
955.
本文提出了一种基于卷积网络的心电信号分类算法,设计了空洞卷积池化金字塔模块,通过不同尺寸的空洞卷积提取信息,再将各通道的信息聚合,在增强网络的特征提取能力的同时可以降低参数量。本文聚焦于窦性心律、房性早搏、心动过速以及心动过缓4种分类,使用的心电图数据集来自医院的实测数据,数据集包含75000名不同检测者的心电记录。经过测试,本文提出的模型在该数据集上取得了0.89的F1值,另外在CinC2017数据集上也达到了0.87的F1值。实验结果表明该分类算法具有优秀的特征提取和分类能力,在心电信号的实时分类中具备应用前景。 相似文献
956.
Mixed plastic waste recycling represents a significant challenge as the phase separation of different components dictates downgraded performance. Polymer-based compatibilizers can offer a promising solution to address this issue, through effectively reducing surface tension and increasing interfacial strength between distinct components to result in improved mechanical and thermal properties of recycled products. This perspective provides an overview of the fundamental concepts for the rational design of copolymer blend compatibilizers and discusses their recent advances, including both preformed and in situ generated systems. Impacts of key material parameters of compatibilizers, such as chain topology, chemical composition, and block sequence on their performance of remediating mixed plastics are discussed. Additionally, reactive compatibilization strategies are also introduced, including in situ formation of polymers, installing functional groups on mixed plastics, and employing dual compatibilization strategies. Looking forward, there are many research and technology opportunities in this area, especially for enabling the use of blend compatibilizers to practically address mixed plastic wastes at scale. Specifically, future compatibilizer design and application should provide strong competitiveness in both cost and energy savings, and carbon emission reduction. Together, the development of blend compatibilizers is an important step in establishing plastic circular economy and creating a more sustainable future. 相似文献
957.
Tsukamoto F Shiba E Taguchi T Sugimoto T Watanabe T Kim SJ Tanji Y Kimoto Y Izukura M Takai SI 《Breast cancer (Tokyo, Japan)》1997,4(4):259-263
Overexpression of P-glycoprotein (Pgp) in tumors is one of the major mechanisms which mediates the multidrug resistance (MDR)
phenotype. To evaluate the prognostic significance of Pgp in breast cancer, Pgp expression was examined in paraffin-embedded
tissue sections of 94 breast cancer specimens by immunohistochemistry. Tissue specimens were obtained by mastectomy without
preoperative chemotherapy. UIC2 monoclonal antibody which recognizes an extracellular epitope of human Pgp was employed. Of
the 94 breast cancer specimens, 35 (37.2%) were positive for Pgp expression. Pgp expression had no correlation with menopausal
or hormone receptor status, axillary lymph node involvement or tumor size. However, a significant correlation was observed
between Pgp expression and disease relapse (p = 0.0322). Pgp-positive patients showed a significantly shorter disease-free survival period than Pgp-negative patients by
the Kaplan-Meier method (p = 0.0433). These results suggest that immunohistochemical detection of Pgp in breast cancer tissue may have prognostic value
after radical operation. 相似文献
958.
Lee YJ Nam SW Seo DW Ahn SH Ko YK Sung DS Han JW Hong SY Lee HW 《Archives of pharmacal research》1997,20(3):239-246
In the present study, liver regeneration rate (%) was increased up to 70% 3 days after partial hepatectomy (PH). Nitric oxide
synthase (NOS) activity in liver tissue as well as serum nitrite/nitrate content had no timed response, revealing no significant
difference between shamoperated and partially hepatectomized rat liver. Contents of free methylarginines in liver tissue were
increased biphasically in a time-dependent manner after PH. However, those in serum did not exhibit the same patterns as in
liver. Taken together, the results suggest that NG-monomethyl-L-arginine (MMA) and NG, NG-dimethylarginine (DMA) play a role in inhibiting nitric oxide (NO) synthesis in regenerating rat liver because the increase
of their contents was synchronized with NOS expression. 相似文献
959.
In order to develop new anti-inflammatory agents having different action mechanisms compared with nonsteroidal and steroidal anti-inflammatory drugs, the culture broths of various actinomycetes isolated from soil were screened using anin vivo mouse ear edma assay and one strain (Streptomyces sp. MT 2705-4: KCTC 8651P) was selected. Activity-guided purification led to the isolation of a polyether compound, dianemycin. Topically, dianemycin showed a potent anti-inflammatory activity in mouse ear edema induced by croton-oil or arachidonic acid. ED(50) value of dianemycin was found to be 0.8 mg/ear compared to 0.4 mg/ear of prednisolone in croton-oil ear edema. However, dianemycin did not show the inhibitory activity in UV-erythema and delayed hypersensitivity reaction. These results indicate that dianemycin is a potential topical anti-inflammatory agent. 相似文献
960.
SEARCHFORHERPESSIMPLEXVIRUSTYPE2(HSV-2)ANDHUMANPAPILLOMAVIRUS(HPV)INTHENORMALANDABNORMALCERVICALSAMPLESZhangWei;张伟;JinShunqia... 相似文献