17β-雌二醇对大鼠脑缺血再灌注损伤脑组织HSP70表达的影响

目的 观察雌二醇对大鼠脑缺血再灌注损伤脑组织Hsp-70表达的影响.方法 72只大鼠随机分为假手术组（8只）、实验对照组及雌二醇治疗组,后两组又进一步分为局灶性脑缺血2h/再灌注3h、6h、12h、24h 组,每时间点8只.线栓法建立大鼠局灶性脑缺血/再灌注损伤模型,采用石蜡切片HE及免疫组化染色法检测脑组织损伤及hsp-70的表达情况.结果 假手术组大鼠未见Hsp-70的表达; 雌二醇治疗组的脑组织缺血半暗带区损伤程度较实验对照组明显减轻;随着再灌注时间的延长,治疗组半暗带区皮质hsp-70的表达较对照组上调,且呈先上升后下降趋势,在12h 为表达高峰;而纹状体区其表达呈进行性下调趋势.结论 17-β雌二醇具有减少脑缺血/再灌注损伤的作用,而半暗带区皮质脑保护蛋白Hsp-70的表达升高可能其是重要机制之一.     

Expression of Heat Shock Protein-70 and Limbic Seizure-induced Neuronal Death in the Rat Brain

The effect of MK-801, a non-competitive N-methyl-D-aspartate (NMDA) antagonist, on the kainic acid-induced expression of the inducible heat shock protein 70 kDa (HSP70) and on neuronal death in the rat hippocampus was investigated. HSP70 is expressed in ?80% of the pyramidal neurons in the CA1 field 1 day after kainic acid injection. The majority of these HSP70-immunopositive neurons exhibited swelling and a hollow appearance in the perikaryon, indicating that they had been injured following kainic acid-elicited limbic seizures. Four days after administration of kainic acid, 87% of the pyramidal neurons in the CA1 field were dead. When a single dose of MK-801 was administered 1 h before kainic acid injection, the number of rats suffering with seizures was reduced, the severity of limbic seizures was attenuated and seizure onset was delayed. Neither HSP70 expression on day 1 nor neuronal loss on day 4 in the CA1 pyramidal cell layer was observed in these animals. A considerable number of HSP70-immunopositive neurons was detected in the dentate hilus, however, and somewhat fewer in the CA3a and CA3c subfields on day 1. Severe neuronal damage in these regions followed on day 4. Interestingly, little HSP70 expression or neuronal loss was observed in the CA3b subfield in these same animals. When a single dose of MK-801 was given 4 h after kainic acid treatment, HSP70 expression was partially blocked; 18% of neurons expressed HSP70 on day 1 and 37% on day 4 in CA1 pyramidal neurons in comparison to the kainic acid controls. About 50% neuronal death was detected in the CA1 pyramidal cell layer 4 days after kainic acid treatment followed by MK-801. When the animals were treated with MK-801 4 h after kainic acid treatment followed by additional daily administration for 3 days, a negligible number of pyramidal neurons expressed HSP70, and the survival of pyramidal cells was significantly increased in the CA1 field. Limbic seizure-induced HSP70 expression not only indicates neuronal injury in the pyramidal cell layer of the hippocampus but also predicts delayed neuronal death, at least in the case of the CA1 field of animals that suffered stage IV—V seizures.     

Induction of heat shock (stress) genes in the mammalian brain by hyperthermia and other traumatic events: a current perspective

Is the heat shock response physiologically relevant? For example, following hyperthermia or ischemia, what neural cell types show induction of heat shock genes and what is the time course of the effect? Initial experiments in this area demonstrated the prominent Induction of a 70 kDa heat shock protein (hsp70) when labeled brain proteins isolated from hyperthermic animals were analyzed. Recently, in situ hybridization and immunocytochemistry have been utilized to map out the pattern of expression of both constitutively expressed and stress-inducible members of the hsp70 multigene family. Different types of neural trauma have been found to induce characteristic cellular responses in the mammalian brain with regard to the type of brain cell that responds by inducing hsp70 and the timing of the induction response. Fever-like temperature causes a dramatic induction of hsp70 mRNA within 1 hr in fiber tracts of the fore-brain and cerebellum, a pattern consistent with a strong glial response to heat shock. Tissue injury, namely, a small surgical cut in the cerebral cortex, induces a rapid and highly localized induction of hsp70 mRNA in cells proximal to the injury site. Using an immunocytochemical approach, a neuronal pattern of induction of hsp70 has been demonstrated following ischemia or kainic acid–induced seizures. It is apparent that the pattern of induction of hsp70 may be a useful early marker of cellular injury and may identify previously unrecognized areas of vulnerability in the nervous system.     

Differential expression of heat shock protein HSP27 in human neurons and glial cells in culture

HSP27 expression was investigated in cultured neurons and glial cells isolated from fetal human brains using immunoblotting and immunocytochemistry. Under unstressed conditions, HSP27 was identified at a high level in astrocytes (>99%), at a low level in neurons (7%), and at a minimally detectable level in microglia (<1%), whereas it was undetectable in oligodendrocytes. Under these conditions, HSP27 was located in the cytoplasm, fractionated into the Triton X-100-soluble phase, and composed chiefly of the basic isoform (HSP27a). After exposure to heat stress (43°C90 min), the level of HSP27 exproion ryas not altered in astrocytes but was elevated significantly in neurons (11–21%) and microglia (4–7%) during 8–48 hr postrecovery periods, while it remained undetectable in oligodendrocytes. In addition, various human neural cell lines exhibited differential patterns of HSP27 expression under unstressed and heat-stressed conditions. Following heat shock treatment (45°C/30 min), granular aggregates of HSP27 were identified in the cytoplasm of astrocytes. Under heat-stressed conditions, HSP27 was distributed within the Triton X-100-insoluble fraction associated with an increase in two more acidic isoforms (HSP27b and HSP27c). HSP27 and αβ-crystallin were coexpressed in astrocytes under unstressed and heat-stressed conditions. When astrocytes were exposed to known HSP27 inducers, hydrogen peroxide and cysteamine reduced the synthesis of HSP27, while estradiol showed no effects. The differential patterns of constitutive and heat-induced expression of HSP27 in cultured human neurons and glial cells suggest that the cellular mechanisms by which HSP27 expression is regulated are different among various cell types in the human central nervous system. © 1995 Wiley-Liss, Inc.     

Effect of the Superior Vena Cava Electrode Surface Area on Defibrillation Threshold in Different Lead Systems

Little data is available comparing the efficacy of the Transvene, Endotak C 70 series, and the active CAN configuration on defibrillation success. In addition, the impact of the superior vena cava (SVC) electrode surface area and length on the active CAN system is unknown. Therefore, we compared the defibrillation efficacy of the Transvene and Endotak C 70 series lead systems with and without the active CAN in dogs. Defibrillation threshold (DFT) testing was randomly performed in 20 dogs. In protocol I [10 dogs), DFT energy was compared in three BV/SVC lead systems with an SVC electrode defibrillating surface area of 90 mm² (Transvene-90), 160 mni² (Transvene-160). 617 mm² (En-dotak), and an RV/CAN configuration. In protocol II (10 dogs), DFT comparison was performed in the Transvene-90/CAN, Transvene-160/CAN. Endotak/CAN, and RV/CAN configurations. In protocol I, in-creasing the SVC surface area from 90 to 160 mm² and from 160 to 617 mm² significantly lowered DFT energy. The Endotak and the RV/CAN systems provided the lowest DET energy requirements. In protocol II, the Endotak/CAN system significantly lowered DFT energy compared to the other three lead configu-rations. In both protocols, the impedance decreased as the SVC surface area increased from 90 to 160 mm². However, no significant reduction in DFT impedance occurred as the SVC surface area increased from the Transvene-160 to the Endotak lead. Increasing the SVC surface area from 90 to 617 mm² in a two coil lead system lowered DFT energy to similar levels provided by the HV/CAN configuration. The addition of an SVC electrode with a surface area of 90 or 160 mm² did not reduce DFT energy compared to the RV/CAN configuration. The Endotak/CAN system, however, provided the lowest DFT requirements.     

高温作业工人血清抗HSP70抗体水平的研究

本研究用免疫印迹技术，以纯化的ＨＳＰ７０为抗原，检测了高温作业工人血清抗ＨＳＰ７０抗体的水平。实验发现，用人体来源的ＨＳＰ７０作为抗原的检测比动物（大鼠）来源的ＨＳＰ７０作为抗原的反应灵敏得多。用人体细胞制备的ＨＳＰ７０作为抗原时，１０例高温作业工人中有２例呈阳性反应，而非高温对照１０人中仅１例呈弱阳性反应，含此抗体阳性血清用动物来源的ＨＳＰ７０作抗原时显著减弱。用动物源的ＨＳＰ７０作抗原，检测５     

Phage displaying epitope of Candida albicans HSP90 and serodiagnosis

Recently, the frequent use of immunosuppressants and chemotherapeutic drugs for cancers has caused an increase in the frequency of life-threatening systemic candidiasis. Studies by Matthews et al^2 indicated HSP90 fragments are major targets for the immune system in infection due to C. albicans, and antiepitope LKVIRK of HSP90 antibody is a serological marker for diagnosis of invasive candidiasis. Cloning and sequencing HSP90 antigen revealed that the linear     

Study on the preparation of recombinant human HSP70 and its presenting-antigen function

Heat shock protein 70 (HSP70 ) isolated fromtumor cells is conjunct with antigen- peptides so thatthe complex can activate immune response againsttumors in vivo[1— 3 ] .But this kind of complex can notbe used in tumor therapy because it is difficult toprepare on large scale.A promising solution to thisproblem will be the application of HSP70 ,which canbe prepared on large scale by genetic engineering,totumortherapy by binding antigen peptides in vitro.Inthisstudy,soluble HSP70 wasexpresse…     

Comparative Study on the Immunogenicity between Hsp70 DNA Vaccine and Hsp65 DNA Vaccine in Human Mycobacterium Tuberculosis

There are 3million deaths perannum worldwidedue to tuberculosis,and AIDS is compounding theproblem.A better vaccine than the live mycobacteri-um currently in use,Bacillus Calmette- Guerin( BCG) ,is needed.Mycobacterium heat shock pro-tein ( HSP) can not only enhance the immune re-sponse,but also keep the antigen characteristics ofmycobacterium itself.Our cooperator,Silva fromLowrie group of British National Medical Academy,cloned the mycobacterium Hsp65 gene into a eukary-otic expressi…