Senescence—like changes induced by expression of p21^Waf1／Cip1 in NIH3T3 cell line

P21^Waf1/Cip1 is a potent cyclin-dependent kinase inhibitor.As a downstream mediator of P53,P21^Waf1/Cip1 involves in cell cycle arrest,differentiation and apoptosis.Previous studies in human cells provided evidence for a link between P21^Waf1/Cip1 and cellular senescence.While in murine cells,the role of P21^Waf1/Cip1 is indefinite.We explored this issue using NIH3T3 cells with inducible P21^Waf1/Cip1 expression.Induc-tion of P21^Waf1/Cip1 triggered G1 growth arrest, and NIH3T3-p21 cells exhibited morphologic features,such as enlarged and flattened cellular shape,specific to the senescence phenotype.We also showed that P21^Waf1/Cip1-transduced NIH3T3 cells expressed β-galactosidase activity at pH6.0 ,which is known to be a marker of senescence.Our results suggest that P21^Waf1/Cip1 can also induce senescence-like changes in murine cells.     

科技竞赛培养创新人才改革初探

根据独立学院所面临的生源、师资和资金等问题,介绍了通过科技竞赛,提高学生创新实践能力的有效途径是鼓励学生积极参加科技竞赛。结合近几年学生参加科技竞赛的实践,分析了科技竞赛活动对提高学生创新实践能力的必要性,从而促进了教学内容、教学方法的改革和大学生科技创新实验室的建设,推动了学生创新能力的培养,改善了学风的好转。     

Gene Regulatory Networks in the Genomics Era

<正>The precise regulation of gene expression is critical to the normal development and biological function of all organisms. Dysregulation of gene expression during early development can result in a spectrum of failures ranging from minor defects to the termination of development. In adult life, dysregulation ncan lead to     

犬心肌细胞分离方法的改良

目的:建立高效可靠的成年犬心肌细胞分离方法,获得高产量与高质量的心肌细胞,以便进行犬心肌细胞收缩功能的研究.方法:采用改良的Langendorff灌流胶原酶消化法分离得到左心室心肌细胞.荧光显微镜观察细胞生长状态和形态并利用单细胞收缩动态边缘检测系统测定心肌细胞收缩功能的改变.结果:结果显示,与传统方法相比,即刻分离的心肌细胞状态良好,复钙后的心肌细胞成活率达到70％-80％,转染重组腺病毒β2-EGFP培养48 h,心肌细胞成活率为60％-70％.给予持续电场刺激,心肌细胞可以保持收缩节律和幅度稳定30 min以上.结论:该方法操作简单,分离的活细胞产量高,质量好,节约实验成本和时间,为心血管相关研究提供良好的细胞模型.     

Improving the evidence base for decision making during a pandemic: the example of 2009 influenza A/H1N1

This article synthesizes and extends discussions held during an international meeting on "Surveillance for Decision Making: The Example of 2009 Pandemic Influenza A/H1N1," held at the Center for Communicable Disease Dynamics (CCDD), Harvard School of Public Health, on June 14 and 15, 2010. The meeting involved local, national, and global health authorities and academics representing 7 countries on 4 continents. We define the needs for surveillance in terms of the key decisions that must be made in response to a pandemic: how large a response to mount and which control measures to implement, for whom, and when. In doing so, we specify the quantitative evidence required to make informed decisions. We then describe the sources of surveillance and other population-based data that can presently--or in the future--form the basis for such evidence, and the interpretive tools needed to process raw surveillance data. We describe other inputs to decision making besides epidemiologic and surveillance data, and we conclude with key lessons of the 2009 pandemic for designing and planning surveillance in the future.     

Nationwide molecular surveillance of pandemic H1N1 influenza A virus genomes: Canada, 2009

Background

In April 2009, a novel triple-reassortant swine influenza A H1N1 virus (“A/H1N1pdm”; also known as SOIV) was detected and spread globally as the first influenza pandemic of the 21^st century. Sequencing has since been conducted at an unprecedented rate globally in order to monitor the diversification of this emergent virus and to track mutations that may affect virus behavior.

Methodology/Principal Findings

By Sanger sequencing, we determined consensus whole-genome sequences for A/H1N1pdm viruses sampled nationwide in Canada over 33 weeks during the 2009 first and second pandemic waves. A total of 235 virus genomes sampled from unique subjects were analyzed, providing insight into the temporal and spatial trajectory of A/H1N1pdm lineages within Canada. Three clades (2, 3, and 7) were identifiable within the first two weeks of A/H1N1pdm appearance, with clades 5 and 6 appearing thereafter; further diversification was not apparent. Only two viral sites displayed evidence of adaptive evolution, located in hemagglutinin (HA) corresponding to D222 in the HA receptor-binding site, and to E374 at HA2-subunit position 47. Among the Canadian sampled viruses, we observed notable genetic diversity (1.47×10⁻³ amino acid substitutions per site) in the gene encoding PB1, particularly within the viral genomic RNA (vRNA)-binding domain (residues 493–757). This genome data set supports the conclusion that A/H1N1pdm is evolving but not excessively relative to other H1N1 influenza A viruses. Entropy analysis was used to investigate whether any mutated A/H1N1pdm protein residues were associated with infection severity; however no virus genotypes were observed to trend with infection severity. One virus that harboured heterozygote coding mutations, including PB2 D567D/G, was attributed to a severe and potentially mixed infection; yet the functional significance of this PB2 mutation remains unknown.

Conclusions/Significance

These findings contribute to enhanced understanding of Influenza A/H1N1pdm viral dynamics.     

435例产妇产后相关激素水平的调查研究及闭经风险和抑郁状况的关系研究

目的:研究435例产妇产后相关激素水平及可能发生闭经的风险,并探讨其与抑郁状况的关系,为临床诊疗提供依据。方法:选取2017年3月到2019年5月期间我院收治的435例产妇为研究对象,根据出血情况将产妇分为出血≥400 m L组(n=26)和出血400 m L组(n=409),根据生产产程将产妇分为产程≥36h组(n=34)和产程36h组(n=401),根据催产素应用情况将产妇分为催产素用量≥20U组(n=41)和催产素用量20U组(n=394),根据是否发生产后抑郁将产妇分为产后抑郁组(n=69)和无产后抑郁组(n=366),检测并对比所有产妇血清中卵泡刺激素(FSH)、促黄体生成激素(LH)、泌乳素(PRL)以及雌二醇(E_2)水平。结果:出血≥400 m L组FSH、LH水平显著高于出血400 m L组,出血≥400 m L组E_2水平显著低于出血400 m L组(P0.05);产程≥36h组FSH、LH水平显著高于产程36h组,产程≥36h组E_2水平显著低于产程36h组(P0.05);催产素用量≥20U组FSH、LH水平显著高于催产素用量20U组,催产素用量≥20U组E_2水平显著低于催产素用量20U组,(P0.05);产后抑郁组FSH、LH水平显著高于无产后抑郁组,产后抑郁组的E_2水平显著低于无产后抑郁组(P0.05);不同组分的PRL水平比较无统计学意义(P0.05)。结论:出血量≥400 m L、产程≥36h和催产素用量≥20U可能是闭经的风险因素,而产后抑郁可能降低产妇的卵巢功能。     

低风险胸痛急性冠状动脉综合征患者心电图特征及其对诊断的价值研究

摘要 目的：分析低风险胸痛急性冠状动脉综合征(acute coronary syndrome,ACS)患者心电图特征及其对诊断的价值。方法：选择我院自2017年1月至2019年8月接诊的194例疑似低风险胸痛ACS患者,均采取心电图检查和冠状动脉造影检查;分析低风险胸痛ACS患者的心电图特征,观察心电图结果与冠状动脉病变支数、狭窄程度的关系,计算心电图诊断低风险胸痛ACS的特异性、敏感性等效能指标,使用受试者工作特征(receiver operating characteristic,ROC)曲线下面积(curve,AUC)定量分析ST段偏移值预测主要不良心血管事件的效能。结果：在194例疑似低风险胸痛ACS患者中,低风险胸痛ACS患者134例,低风险不稳定型心绞痛(UA)患者心电图表现以ST-T缺血性改变为主,发作时改变明显或呈现伪性改善;低风险非ST段抬高的心肌梗死(non-ST-segment elevation myocardial infarction,NSTEMI)患者心电图表现为肢体和胸导联ST段压低,T波低平、倒置,ST-T改变持续存在和呈动态衍变;低风险胸痛ACS患者心电图结果与冠状动脉病变支数无关(P＞0.05),与狭窄程度有关(P＜0.05);心电图诊断低风险胸痛ACS的特异性为71.67 %,敏感性为69.40 %,阳性预测值为84.55 %,阴性预测值为51.19 %,符合率为70.62 %;所有患者均获得随访,经ROC曲线分析,ST段偏移值预测低风险胸痛ACS患者发生主要不良心血管事件的最佳截值为1.85 mm,AUC为0.695,对比全球急性冠状动脉事件注册(GRACE)风险评分的0.675,差异无统计学意义(P＞0.05)。结论：低风险胸痛ACS患者心电图具有多样化,与冠状动脉狭窄程度有关,有助于初步诊断和风险评估,且ST段偏移值预测主要不良心血管事件的效能较好,值得进一步研究应用。     

Relative importance of water, energy, and heterogeneity in determining regional pteridophyte and seed plant richness in China

Environmental variables, such as ambient energy, water availability, and environmental heterogeneity have been frequently proposed to account for species diversity gradients. How taxon-specific functional traits define large-scale richness gradients is a fundamental issue in understanding spatial patterns of species diversity, but has not been well documented. Using a large dataset on the regional flora from China, we examine the contrast spatial patterns and environmental determinants between pteridophytes and seed plants which differ in dispersal capacity and environmental requirements. Pteridophyte richness shows more pronounced spatial variation and stronger environmental associations than seed plant richness. Water availability generally accounts for more spatial variance in species richness of pteridophytes and seed plants than energy and heterogeneity do, especially for pteridophytes which have high dependence on moist and shady environments. Thus, pteridophyte richness is disproportionally affected by water-related variables; this in turn results in a higher proportion of pteridophytes in regional vascular plant floras (pteridophyte proportion) in wet regions. Most of the variance in seed plant richness, pteridophyte richness, and pteridophyte proportion explained by energy is included in variation that water and heterogeneity account for, indicating the redundancy of energy in the study extent. However, heterogeneity is more important for determining seed plant distributions. Pteridophyte and seed plant richness is strongly correlated, even after the environmental effects have been removed, implying functional linkages between them. Our study highlights the importance of incorporating biological traits of different taxonomic groups into the studies of macroecology and global change biology.     

Increased T cell proliferative responses to islet antigens identify clinical responders to anti-CD20 monoclonal antibody (rituximab) therapy in type 1 diabetes

Type 1 diabetes mellitus is believed to be due to the autoimmune destruction of β-cells by T lymphocytes, but a single course of rituximab, a monoclonal anti-CD20 B lymphocyte Ab, can attenuate C-peptide loss over the first year of disease. The effects of B cell depletion on disease-associated T cell responses have not been studied. We compare changes in lymphocyte subsets, T cell proliferative responses to disease-associated target Ags, and C-peptide levels of participants who did (responders) or did not (nonresponders) show signs of β-cell preservation 1 y after rituximab therapy in a placebo-controlled TrialNet trial. Rituximab decreased B lymphocyte levels after four weekly doses of mAb. T cell proliferative responses to diabetes-associated Ags were present at baseline in 75% of anti-CD20- and 82% of placebo-treated subjects and were not different over time. However, in rituximab-treated subjects with significant C-peptide preservation at 6 mo (58%), the proliferative responses to diabetes-associated total (p = 0.032), islet-specific (p = 0.048), and neuronal autoantigens (p = 0.005) increased over the 12-mo observation period. This relationship was not seen in placebo-treated patients. We conclude that in patients with type 1 diabetes mellitus, anti-B cell mAb causes increased proliferative responses to diabetes Ags and attenuated β-cell loss. The way in which these responses affect the disease course remains unknown.