粘附分子与脑缺血后炎症

粘附分子主要包括选择素 ,免疫球蛋白超级家族及整合素 ,它们之间的相互作用有利于白细胞的粘附和迁移。脑缺血后 ,缺血区产生的具有强大致炎作用的细胞因子可诱导脑缺血区多种粘附分子的表达 ,并进一步促进白细胞的浸润 ,产生炎症反应 ,这是脑组织在缺血后发生迟发性损伤的重要原因。因此研究粘附分子在脑缺血中的表达及作用 ,对脑缺血的治疗具有重要意义。     

TNF-α与G-CSF在脑缺血-再灌注损伤中的研究

再灌注损伤是由多种原因引起的复杂的病理生理过程,而级联的炎症反应是导致脑细胞损伤的重要病理环节。脑缺血再灌注后,浸润的炎性细胞产生的大量炎性介质,在再灌注损伤中占有重要地位。肿瘤坏死因子α(TNF-α)是一种具有广泛生物学功能的细胞因子,参与机体免疫应答和炎症反应TNF-α是细胞间粘附分子-1(ICAM-1)表达的强诱导剂,抑制细胞粘附分子(ICAM-1)表达可显著减低再灌注时白细胞粘附活化,减少损伤脑面积起保护作用。粒细胞集落刺激因子(G-CSF)能通过STAT途径减少缺血区肿瘤坏死因子-α等的释放,引起人们对其在脑缺血-再灌注损伤中的作用的极大关注。     

TNF-α与G—CSF在脑缺血-再灌注损伤中的研究

再灌注损伤是由多种原因引起的复杂的病理生理过程,而级联的炎症反应是导致脑细胞损伤的重要病理环节。脑缺血再灌注后,浸润的炎性细胞产生的大量炎性介质,在再灌注损伤中占有重要地位。肿瘤坏死因子α（TNF-α）是一种具有广泛生物学功能的细胞因子,参与机体免疫应答和炎症反应TNF-α是细胞间粘附分子-1（ICAM-1）表达的强诱导剂,抑制细胞粘附分子（ICAM-1）表达可显著减低再灌注时白细胞粘附活化,减少损伤脑面积起保护作用。粒细胞集落刺激因子（G-CSF）能通过STAT途径减少缺血区肿瘤坏死因子-α等的释放,引起人们对其在脑缺血-再灌注损伤中的作用的极大关注。     

白藜芦醇减轻脑缺血再灌注损伤与激活Wnt/β-catenin相关

研究白藜芦醇对脑缺血再灌注损伤的作用及机制。利用结扎大脑中动脉的方法制备局灶脑缺血再灌注损伤模型。将实验大鼠随机分为假手术组,脑缺血再灌注损伤组,白藜芦醇组和尼莫地平组,观察白藜芦醇对大鼠肿瘤坏死因子α(TNF-α)、单核细胞趋化因子-1(MCP-1)、白介素-6(IL-6)、Wnt、β-catenin、Bax和BCL-2的表达以及对大鼠神经行为和脑梗死面积的影响。结果显示白藜芦醇可明显改善大鼠神经功能缺陷和减少脑梗死面积,并可上调Wnt、β-catenin、cyclin D1、survivin、和BCL-2的表达,下调促炎症细胞因子TNF-α、MCP-1和IL-6的表达。说明白藜芦醇可激活Wnt/β-catenin信号通路发挥对脑缺血再灌注损伤的保护作用。     

细胞因子在ARDS发病机制中的作用

细胞因子是由多种细胞产生的多肽或低分子糖蛋白,在人体内含量极微,在pg水平就发挥作用。作为特异性免疫反应和非特异性免疫反应的蛋白质,细胞因子以自分泌、旁分泌、或内分泌方式产生,与相应的细胞表面受体结合,在局部或全身发挥复杂的生物学效应,它们的代谢异常和疾病的发生、发展有着密切的关系。有些细胞因子已应用于临床的生物学治疗,具有深远的临床应用价值,故对细胞因子的研究将是一个越来越重要的课题。急性肺损伤(ALI)/急性呼吸窘迫综合征(ARDS)发病机制错综复杂,大量临床和实验室研究证明多种效应细胞释放的炎症介质是造成ARDS的"中心环节",其中TNF-α、IL-1、IL-8、IL-10、CXC趋化因子等细胞因子在ARDS发病中的作用尤为重要。本文就细胞因子在ARDS发病机制中的作用做一综述。     

SARS死亡病例肺组织中细胞因子的表达及意义

目的研究重症SARS患者肺组织内细胞因子TNF,IL-1α,IL-1β,IL-6,IL-8和IL-10的表达及定位,探讨重症SARS患者弥漫性肺泡损伤的发病机制。方法应用免疫组织化学染色(SABC法)和定量分析方法对8例SARS死亡病例肺组织中TNF,IL-1α,IL-1β,IL-6,IL-8和IL-10进行检测。结果TNF,IL-1α,IL-1β,IL-6,IL-8和IL-10在8例SARS死亡病例肺组织中均有阳性表达,多种细胞均可表达这些细胞因子;与普通肺炎组比较,SARS死亡病例肺组织中细胞因子水平显著升高;SARS死亡病例细胞因子水平在病程不同阶段间的表达有差异。结论TNF,IL-1α,IL-1β,IL-6,IL-8和IL-10可能参与重症SARS患者弥漫性肺泡损伤的发生与发展。     

炎症Caspase与相关疾病

Caspase家族是一类与细胞凋亡和炎症反应重要相关的蛋白酶,其中与炎症相关的主要有Caspase-1、-4、-5、-11、-12,总称为炎症Caspase,主要与促炎症细胞因子IL-1的产生有关。IL-1处于免疫反应的上游,能刺激多种炎症细胞因子和多种效应分子的产生,引起神经细胞凋亡和毒性、关节疼痛和损伤、肝细胞凋亡、急性胰腺炎等与炎症相关疾病。因此,抑制炎症Caspase对治疗炎症相关疾病有重要意义。     

高压氧预处理对大鼠局灶性脑缺血再灌注损伤的保护作用

目的:研究高压氧预处理对大鼠脑缺血再灌注损伤的保护作用。方法:36只SD大鼠随机分为假手术组、模型组及高压氧预处理组,每组12只。高压氧预处理组大鼠在造模前5天给予高压氧预处理。采用线栓法建立大鼠脑缺血再灌注模型,观察高压氧预处理对脑缺血再灌注损伤大鼠神经功能缺损评分、脑梗死面积的影响,检测大鼠缺血脑组织COX-2 mRNA和蛋白的表达以及IL-1β、TNF-α、MDA的含量。结果:高压氧预处理可明显改善脑缺血再灌注大鼠神经功能缺损评分,减少脑梗死面积,降低COX-2m RNA和蛋白表达量,抑制IL-1β、TNF-α的表达,降低MDA水平。结论:高压氧预处理对大鼠脑缺血再灌注损伤具有明显的保护作用,其机制可能与抑制IL-1β、TNF-α、COX-2的表达以及减弱脂质过氧化反应有关。     

细胞因子在脑缺血中的介导作用

脑缺血后内皮细胞及其它活性细胞可分泌多种细胞因子 ,而许多细胞因子又可反作用于内皮细胞 ,破坏血脑屏障的完整性 ,进而造成脑神经损害。本文综合阐述脑缺血损害病理过程中起主要作用的细胞因子。1　白介素 - 1 ( IL- 1 )　　IL- 1可由多种活性细胞合成分泌 ,胶质细胞和内皮细胞也可合成 ,它是一类具有广泛作用的多肽。人 IL- 1分子量为 1 5～ 1 7KD,活性形式有 IL-1α、 IL - 1β、 IL - 1 rα三种形式。 IL - 1β是血浆和组织液中的主要形式 ,也是脑组织中的主要形式。它不仅能够协同其它细胞因子促进 B、T细胞活化 ,而且能够诱…     

人白细胞介素4中试规模制备纯化工艺建立

人白细胞介素4(hIL-4)是由Th2分泌的细胞因子,具有多种生物学功能,在人体免疫网络中具有重要的作用。它具有对T细胞、B细胞、胸腺细胞、造血干细胞等多种细胞的增殖效应,促进B细胞的分化,强化抗原表达,提高机体免疫功能;能与IL-2、GM-CSF、IL-10等多种细胞因子产生正协同效应,因而对免疫缺陷、肿瘤、造血障碍、感染性炎症等可产生积极的疗效。国外正进行Ⅱ期临床试验。     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

History of the discovery of the mode of transmission of yellow fever virus

This essay documents and examines the historical circumstances and events surrounding the discovery of the mode of transmission of yellow fever virus in Cuba. Close scrutiny of the articles published by Walter Reed and his colleagues in 1900, 1901 and 1902 reveals their limitations as historic documents. Fortunately, other sources of information from that period survive in letters and documents written by individuals involved in the quest for the mode of transmission. Examination and comparison of those sources of information unveiled a fascinating story which reveals that misunderstandings engendered by published articles accorded merit where it was not fully due.     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.