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81.
82.
1. Thyroid hormones play important roles in the development of the brain. Increasing evidence suggests that the deprivation of thyroid hormones in the early developmental stage causes structural and functional deficits in the CNS, but the precise mechanism underlying this remains elusive. In this study, we investigated the effects of thyroid hormones on synapse formation between cultured rat cortical neurons, using a system to estimate functional synapse formation in vitro. 2. Exposure to 10(-9) M thyroid hormones, 3,5,3'-triiodothyronine or thyroxine, caused an increase in the frequency of spontaneous synchronous oscillatory changes in intracellular calcium concentration, which correlated with the number of synapses formed. 3. The detection of synaptic vesicle-associated protein synapsin I by immunocytochemical and immunoblot analysis also confirmed that exposure to thyroxine facilitated synapse formation. 4. The presence of amiodarone, an inhibitor of 5'-deiodinase, or amitrole, a herbicide, inhibited the synapse formation in the presence of thyroxine. 5. In conclusion, we established a useful in vitro assay system for screening of miscellaneous chemicals that might interfere with synapse formation in the developing CNS by disrupting the thyroid system.  相似文献   
83.
Multixenobiotic defence mechanism (MXDM) consists in a cellular system that functions as membrane extrusion pumps effluxing organic compounds out of the cells. In bivalves, it represents a primordial protection against toxic effects of organic xenobiotics in preventing their cellular accumulation. It has raised attention during the last decade for its potential to be used as a biomarker of pollution. This article reviews the fundamental knowledge on the MXDM system in bivalves and the methods proposed to assess its activity. Finally, it reviews the major results of laboratory and field studies that enabled to hypothesise that MXDM could be used as a biomarker of environmental stress rather than of pollutant exposure.  相似文献   
84.
摘要 目的:探讨miR-155在脓毒症致肠道功能障碍中的表达及作用。方法:(1)临床实验:以2022年5月至2022年8月入住新疆医科大学第一附属医院重症医学科的脓毒症患者和同期健康体检者为研究对象,根据急性胃肠损伤分级(AGI)将脓毒症患者分为AGI组和非AGI组。根据28 d生存情况分为存活组和死亡组,采用实时荧光定量反转录-聚合酶链反应(qRT-PCR)法前瞻性观察各组外周血miR-155的变化。(2)体内实验:将20只雄性S/D大鼠按照随机数字表法分为假手术组(sham组)和盲肠结扎穿孔术组(CLP组),采用qRT-PCR及Western blot法检测miR-155、肠道紧密连接蛋白(ZO-1、claudin-1)的表达,ELISA法检测大鼠肠道组织中IL-1β、IL-6、IL-18的表达水平。(3)体外实验:培养人结直肠腺癌细胞(Caco-2),并分为正常对照组(完全培养基培养48 h)、脂多糖组(完全培养基培养24 h后加入10 μg/mL LPS处理24 h)。采用qRT-PCR检测miR-155的表达。在倒置荧光显微镜下观察细胞形态的变化。采用CCK-8检测细胞活力。采用免疫荧光观察Caco-2细胞中紧密连接蛋白ZO-1分布的变化。并行细胞旁通透性实验,观察两组细胞旁通透性的变化。结果:(1)脓毒症组和健康对照组相比,脓毒症患者外周血miR-155较健康对照组明显升高,差异具有统计学意义(P<0.05)。AGI组患者外周血miR-155表达较非AGI组明显升高,差异具有统计学意义(P<0.05)。脓毒症死亡患者外周血miR-155表达显著升高(P<0.05)。(2)应用CLP模型进行体内动物实验,CLP组大鼠肠道组织miR-155表达较假手术组(sham组)明显升高。CLP组大鼠肠道紧密连接蛋白(ZO-1、claudin-1)较sham组下降,差异具有统 计学意义(P<0.05)。ELISA结果提示,CLP大鼠肠道组织中IL-1β、IL-6、IL-18水平较sham组显著升高(P<0.05),且肠道组织中miR-155水平与IL-1β、IL-6、IL-18呈正相关(r=0.542,r=0.906,r=868,P<0.05)。(3)与正常对照组相比,经LPS处理后细胞形态破坏、细胞间紧密连接破坏、细胞活力减弱、细胞旁通透性增加。结论:脓毒症发生时伴有肠道屏障功能障碍,miR-155在脓毒症肠道屏障功能障碍中表达升高,并可能通过促进炎症因子的释放参与脓毒症肠道屏障功能障碍的发生发展。miR-155异常表达对脓毒症患者早期肠道功能障碍诊断及预后的评估具有重要价值,可作为脓毒症早期肠道损伤诊断及预后情况的重要指标。  相似文献   
85.
摘要 目的:探究胃癌患者血清外泌体长链非编码RNA-MIR100HG(lncRNA-MIR100HG)及微小核糖核酸-100(miR-100)表达情况,并分析其与患者临床病理特征和无疾病进展生存率之间的相关性。方法:收集60例胃癌患者和60例良性疾病患者,提取外泌体,检测lncRNA-MIR100HG/miR-100的表达情况并进行组间比较。采用Pearson相关分析lncRNA-MIR100HG与miR-100表达水平的相关性,应用单因素卡方检验分析与胃癌患者临床病理特征相关性,采用Kaplan-Meier生存分析lncRNA-MIR100HG/miR-100表达情况与无疾病进展生存率。结果:(1)胃癌组患者血清lncRNA-MIR100HG显著高于,miR-100相对表达水平显著低于胃良性疾病组(P<0.05);(2)Pearson相关分析结果显示血清lncRNA-MIR100HG和miR-100存在显著负相关关系(r=-0.483,P<0.05);(3)单因素卡方检验分析结果显示:胃癌患者血清lncRNA-MIR100HG相对表达水平与肿瘤大小、分化程度、肿瘤浸润深度、临床分期、淋巴结转移和远处转移相关,血清miR-100相对表达水平与肿瘤大小、分化程度、临床分期和淋巴结转移相关(P<0.05);(4)血清lncRNA-MIR100HG、miR-100低水平表达胃癌患者PFS显著长于高水平患者(χ2=37.371,P<0.05),miR-100高水平表达胃癌患者PFS显著长于低水平患者(χ2=28.631,P<0.05)。结论:胃癌患者血清外泌体lncRNA-MIR100HG/miR-100表达水平与肿瘤大小、肿瘤浸润深度、临床分期等病理特征相关,lncRNA-MIR100HG高表达与miR-100低表达可能提示胃癌患者预后越差。  相似文献   
86.
摘要 目的:探讨喉鳞状细胞癌(LSCC)组织miR-1207-5p、miR-186-5p表达水平与磷脂酰肌醇3-激酶/蛋白激酶B(PI3K/Akt)信号通路、临床病理特征和预后的关系。方法:选取2017年1月至2020年1月南充市中心医院收治的120例LSCC患者,取手术切除的LSCC组织和癌旁组织。检测miR-1207-5p、miR-186-5p、PI3K mRNA、Akt mRNA表达。患者出院后随访3年,统计总生存(OS)和无复发生存(RFS)情况。分析miR-1207-5p、miR-186-5p与PI3K、Akt的相关性以及影响LSCC患者预后的因素。结果:LSCC组织miR-1207-5p、miR-186-5p表达低于癌旁组织(P<0.05),PI3K mRNA、Akt mRNA表达高于癌旁组织(P<0.05)。LSCC组织miR-1207-5p、miR-186-5p表达与PI3K mRNA、Akt mRNA表达呈负相关(P<0.05)。肿瘤直径≥1 cm、低分化、TNM分期Ⅲ期、颈部淋巴结转移LSCC组织中miR-1207-5p、miR-186-5p表达低于肿瘤直径<1 cm、中高分化、TNM分期Ⅰ~Ⅱ期、无颈部淋巴结转移(P<0.05)。miR-1207-5p低表达、miR-186-5p低表达LSCC患者3年总生存(OS)率和无复发生存(RFS)率低于miR-1207-5p高表达、miR-186-5p高表达LSCC患者(P<0.05)。多因素COX回归分析显示TNM III期、颈部淋巴结转移是LSCC患者复发和死亡的危险因素(P<0.05),高miR-1207-5p、高miR-186-5p是保护因素(P<0.05)。结论:LSCC组织中miR-1207-5p和miR-186-5p表达均下调,与LSCC恶性病理特征、PI3K/Akt信号通路激活以及低生存率有关。  相似文献   
87.
88.
The epr spectra at 4.2 K of inhibitor derivatives of cobalt carbonic anhydrase have been recorded. The spectra can be grouped into two classes according to whether the low-field signal is broad or sharp and with g ranges of 6.1–6.8, 2.3–2.9, 1.6–1.8, and 5.8–6.2, 2.2–2.8, 1.5–1.8, respectively. The two kinds of spectra have been empirically related to the features of the room-temperature solution electronic spectra. A third kind of epr spectrum with a single broad signal is obtained when the inhibitor is in large excess.The possibility of using the epr spectra for deducing the geometry of cobalt enzymes is discussed.  相似文献   
89.
The biophysical properties of a series of glycosyl dialkyl- and diacyl-glycerols bearing unsaturated or chiral methyl branched chains in the tail, and di- and trisaccharide carbohydrate headgroups are described. Thermotropism was investigated by polarising microscopy, the lyotropism was investigated by small angle X-ray diffraction and by the contact preparation method, and the gel to liquid crystalline phase transition by FT-IR-spectroscopy. The compounds displayed thermotropic Smectic A (SmA), cubic and columnar phases, whereas in the lyotropic phase diagram lamellar, hexagonal and cubic phases are found. The introduction of unsaturated or methyl branched chains leads to liquid crystallinity at ambient temperature. The difference between the 1,3-oleyl-glycerol maltoside and the corresponding 1,2-oleoyl-glycerol maltoside is small.  相似文献   
90.
The use of a diversity of resistance genes limits the development of polycyclic epidemics caused by airborne pathogens and reduces the risk that resistance be overcome by virulent races. Diversity can be easily achieved by growing mixtures of cultivars with different resistance genes and homogeneous agronomic traits. The mechanisms by which disease is reduced in cultivar mixtures include the loss of inoculum due to the presence of resistant plants between susceptible ones and resistance induced by avirulent pathogens. The complementary effects of individual mixture components reacting to disease pressure and to abiotic stresses result in greater yield stability compared with pure stands. The quality of products from mixtures is at least equal to that obtained with pure stands. This type of resistance management is applicable to both annual and perennial crops.  相似文献   
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