甲异靛对Jurkat细胞AKT信号通路的影响及其在细胞凋亡中作用的研究

目的:探讨甲异靛对Jurkat细胞AKT信号通路的影响及其在甲异靛诱导Jurkat细胞凋亡中的作用.方法:采用XTT法检测甲异靛对Jurkat细胞的生长抑制作用,应用流式细胞术以及DNA片段分析检测甲异靛诱导Jurkat细胞凋亡的情况.应用Western Blot检测CASPASE家族成员及AKT信号通路相关蛋白在甲异靛作用前后的表达或磷酸化情况.通过电转染方法使Jurkat细胞高表达外源性活化AKT,并进一步分析其对甲异靛诱导细胞凋亡作用的影响.结果:甲异靛抑制Jurkat细胞增殖,随着药物浓度增加抑制作用增强,IC50为10.2 μmol/L;5～20 μmol/L甲异靛诱导Jurkat细胞凋亡且凋亡效应具有浓度依赖性;甲异靛诱导细胞凋亡过程中伴随CASPASE 2,3,8,9的活化,50 μmol/L CASPASE抑制剂z-VAD-fmk 可阻断甲异靛诱导的Jurkat细胞凋亡 .甲异靛降低Jurkat细胞AKT信号通路中AKT,RAF,PDK1,以及ERK1/2 的磷酸化水平;15 μmol/L LY294002)(PI3K-AKT抑制剂)可显著提高甲异靛诱导Jurkat细胞凋亡的作用.甲异靛同样诱导高表达外源性活化AKT的 Jurkat细胞凋亡,但LY294002不能增强甲异靛对高表达外源性活化AKT的 Jurkat细胞的凋亡诱导效应. 结论:甲异靛显著抑制Jurkat细胞增殖,通过活化CASPASE途径诱导Jurkat细胞的凋亡. 甲异靛诱导细胞凋亡过程中伴AKT磷酸化水平的降低,AKT活性的降低并非甲异靛诱导凋亡的惟一因素,但参与甲异靛与PI3K-AKT抑制剂协同诱导Jurkat细胞的凋亡的过程.     

三叶因子家族在胃癌发生中的作用机制

三叶因子家族（trefoil factor family，TFF）是一群主要由胃肠道黏液细胞分泌的小分子多肽，在黏膜修复和重建以及肿瘤的发生、发展过程中发挥重要作用，对其结构功能、遗传学改变等分子机制的研究一直是近20余年的研究热点。TFF在肠型胃癌中表达降低甚至缺失，在弥漫型胃癌中高表达。其在胃癌发生、发展过程中的机制涉及肿瘤抑制、促进肿瘤侵袭浸润以及促癌与抑癌的双重机制。通过对TFF在胃癌发生、发展中机制的深入研究，有望在胃癌防治方面开辟新途径。     

The stress of aging

Although the evolutionary theories of aging are quite well established, our knowledge about how we age is still very limited. The abundance and heterogeneity of available mechanistic theories of aging implicitly suggest that this phenomenon is overly complex and unlikely to be explained by a single pathway. Moreover, although aging remains a unique process, it is characterized by heterogeneous manifestations, not only determining inter-individual variations, but even intra-individual diversities. Such heterogeneity renders the inner nature of the aging process of difficult evaluation in older persons due to the potential biases introduced by multiple age-related social, biological, and clinical factors (and responsible for the evidence-based issue in geriatrics). Moving from the difficulties in translating anti-aging preclinical interventions into clinical trials, an alternative approach is illustrated. We encourage moving to a holistic evaluation of aging by adopting specific and consequent modifications in the design and conduction of clinical research. Such approach is today commonly applied in the clinical setting where the complexity of older patients often requires multidimensional interventions to adequately target the geriatric syndromes. Consistently, interventions targeting the aging process may result ineffective if too focused on a single underlying causal mechanism and/or failing to capture the complexity of the phenomenon. In this context, frailty (a geriatric syndrome characterized by age-related declines occurring across multiple physiologic systems) may indeed represent a clinically relevant threshold throughout the continuum of the aging process and a promising benchmark to test multidomain interventions against age-related conditions.     

长期不进展者抗HIV-1相关机制的研究进展

临床实践调查发现,Ⅰ型艾滋病病毒（HIV-1）感染存在不同的病程进展模式,长期不进展者（LTNPs）是指,在HIV-1感染者中,小部分未接受抗病毒治疗而保持病程长期不进展的个体。然而是什么机制使得这些HIV-1感染者疾病长期不进展？近年来有关LTNPs抗HIV-1的作用机制受到越来越多的关注。文章收集了有关LTNPs最近的研究进展,着重从机体免疫学、宿主遗传学、病毒生物学三方面进行综述。     

幽门螺杆菌致癌机制的研究进展

胃癌是常见的消化道恶性肿瘤,死亡率较高。胃癌的发生是一个多因素、多步骤的过程。深入研究胃癌的发病机制对其防治起重要作用。幽门螺杆菌（Hpylori）与胃癌的发生密切相关,目前H．pylori致癌机制的研究主要包括基因不稳定性、细胞因子、胃上皮细胞增殖和凋亡、H．pylori毒力因子、环氧合酶-2、免疫等方面。本文就此作一综述。     

肿瘤多药耐药机制研究进展

肿瘤多药耐药(MDR)是目前临床肿瘤化疗失败的主要原因之一.关于肿瘤多药耐药产生的机制有多种,针对这些不同的机制来研发相应的逆转药物则是目前解决临床耐药现象的主要途径.就目前国内外肿瘤多药耐药机制的研究进展作一综述.     

Trichloroethylene: Mechanistic,epidemiologic and other supporting evidence of carcinogenic hazard

The chlorinated solvent trichloroethylene (TCE) is a ubiquitous environmental pollutant. The carcinogenic hazard of TCE was the subject of a 2012 evaluation by a Working Group of the International Agency for Research on Cancer (IARC). Information on exposures, relevant data from epidemiologic studies, bioassays in experimental animals, and toxicity and mechanism of action studies was used to conclude that TCE is carcinogenic to humans (Group 1). This article summarizes the key evidence forming the scientific bases for the IARC classification. Exposure to TCE from environmental sources (including hazardous waste sites and contaminated water) is common throughout the world. While workplace use of TCE has been declining, occupational exposures remain of concern, especially in developing countries. The strongest human evidence is from studies of occupational TCE exposure and kidney cancer. Positive, although less consistent, associations were reported for liver cancer and non-Hodgkin lymphoma. TCE is carcinogenic at multiple sites in multiple species and strains of experimental animals. The mechanistic evidence includes extensive data on the toxicokinetics and genotoxicity of TCE and its metabolites. Together, available evidence provided a cohesive database supporting the human cancer hazard of TCE, particularly in the kidney. For other target sites of carcinogenicity, mechanistic and other data were found to be more limited. Important sources of susceptibility to TCE toxicity and carcinogenicity were also reviewed by the Working Group. In all, consideration of the multiple evidence streams presented herein informed the IARC conclusions regarding the carcinogenicity of TCE.     

microRNAs与心肌梗死

microRNAs（miRNAs）是一类内源性的非编码单链小分子RNA,约22个核苷酸。miRNAs通过调控其靶基因的表达,参与细胞发育、增殖、分化、凋亡等一系列重要的生理学途径。近些年的研究发现,miRNAs在心肌梗死的发生、发展过程中起着关键的作用。现就miRNAs在心肌梗死发生、发展过程中的作用机制进行阐述。     

NT-3转染骨髓间充质干细胞对脑缺血再灌注的机制研究

目的研究神经营养素-3(neurotrophin-3,NT-3)转染的骨髓间充质干细胞(BMSCs)移植对脑缺血再灌注损伤的作用机制。方法制作脑缺血再灌注损伤模型,将60只大鼠根据注射物不同分为3组:生理盐水对照组、BMSCs组和NT-3+BMSCs组(n=20),观察不同时间3组大鼠的神经学功能评分、脑组织光镜观察、TUNEL法检测神经元细胞的凋亡及丙二醛含量情况。结果 BMSCs+NT-3组移植后大鼠神经学功能评分较BMSCs组低,而BMSCs组较NS组较低,两组间比较均有统计学意义(P0.05);BMSCs+NT-3组脑组织光镜观察细胞形态学变化最轻;BMSCs组神经元凋亡较NS组减少,BMSCs+NT-3组的神经元凋亡数量较BMSCs组减少,两组间比较均有统计学意义(P0.05);NS组丙二醛(MDA)含量明显高于BMSCs组(P0.05);而BMSCs+NT-3转染组明显低于BMSCs组(P0.05)。结论大鼠BMSCs经NT-3转染后相互促进,移植于急性脑缺血再灌注损伤通过减缓神经元细胞凋亡、降低丙二醛含量抑制自由基的脂质过氧化反应进行修复。     

Hyperglycemia in COVID-19 infection without diabetes mellitus: Association with inflammatory markers

BACKGROUND New onset hyperglycemia is common in patients with severe coronavirus disease 2019(COVID-19) infection. Cytokine storm due to COVID-19 infection is an essential etiology for new-onset hyperglycemia, but factors like direct severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)-induced pancreatic β-cell failure have also been postulated to play a role.AIM We plan to investigate further the mechanisms underlying SARS-CoV-2 infectioninduced hyperglycemia, particularly the rationale ...