HO-1在保护缺氧-复氧心脏中的作用及其机制研究

目的：研究血红素氧化酶1（HO-1）在对抗 心肌缺氧-复氧损伤中的作用，并探讨环氧化酶2（COX-2）是否参与其作用机制。 方法：采用离体大鼠心脏Langendorff灌流模型，观察心功能和酶学等指标。 结果：（1）HO-1的诱导剂高铁血红素可明显抑制缺氧-复氧心脏LVEDP增高 ，LVDP和±dp/dtmax的下降；减少复氧期LDH释放，缩小心肌梗死面积（P <0.01）。（2）HO-1的抑制剂可加重缺氧-复氧心脏LVDP和±dp/dtmax下 降，LDH释放和梗死面积明显高于单纯缺氧-复氧组（P<0.05）。（3）GC的抑制剂亚甲 蓝和COX-2的抑制剂塞来昔布均可部分取消高铁血红素降低缺氧-复氧心脏LVEDP，增加LVDP 和±dp/dtmax的作用，使LDH的释放和梗死面积明显增加（P<0.05） 。 结论：诱导HO-1增加可保护缺氧-复氧心肌，其作用可能通过激动鸟苷酸 环化酶途径，继而调节COX-2的活性来完成。     

鸟苷酸环化酶参与血红素氧化酶1对抗心肌缺血/再灌注损伤的作用

目的研究血红素氧化酶1(HO-1)在对抗心肌缺血/再灌注损伤中的作用,并探讨鸟苷酸环化酶(GC)是否参与其作用机制。方法采用离体大鼠心脏Langendorff灌流模型,观察心功能和酶学等指标。结果(1)HO-1的诱导剂高铁血红素可明显抑制缺血/再灌注心脏左室舒张末压(LV-EDP)增高,左室舒张压(LVDP)和最大左室收缩、舒张速率(±dP/dtmax)的下降;减少复氧期乳酸脱氢酶(LDH)释放,缩小心肌梗死面积(P<0.01)。(2)HO-1的抑制剂可加重缺血/再灌注心脏LVDP和±dP/dtmax下降,LDH释放和梗死面积明显高于单纯缺血/再灌注组(P<0.05)。(3)GC的抑制剂亚甲蓝可部分取消高铁血红素降低缺血/再灌注心脏LVEDP,增加LVDP和±dP/dtmax的作用,使LDH的释放和梗死面积明显增加(P<0.05)。结论诱导HO-1增加可保护缺血/再灌注心肌,其作用可能通过激动鸟苷酸环化酶途径来完成。     

线粒体钙单向转运体在心肌低氧预处理中的作用

目的：观察线粒体钙单向转运体在低氧预处理心肌保护中的作用及其与线粒体通透性转换孔之间的关系。 方法： 采用Langendorff灌流离体大鼠心脏模型,记录左室发展压（LVDP）、左室压上升/下降最大速率（±dp/dtmax）和左室舒张末期压力（LVEDP）。结扎冠脉左前降支30 min作为低氧,松开结扎复氧120 min。全心停灌5 min复氧5 min两个循环作为低氧预处理。用紫外分光光度法检测复氧5、10、15、20和30 min的冠脉流出液乳酸脱氢酶（LDH）活性。用TTC染色法测心肌梗死面积。 结果： 低氧预处理和低氧后复氧期的前10 min用钌红（5 μmol/L）处理均可促进LVDP、±dp/dtmax和LVEDP的恢复，减小心肌梗死面积，减少LDH释放。复氧期的前10 min用精胺(20 μmol/L)处理可减弱低氧预处理的心脏作用。用环孢菌素A（0.2 μmol/L）处理20 min（复氧前5 min到复氧期的前15 min）则减弱上述精胺在低氧预处理中的心肌作用。 结论： 低氧预处理引起的心肌保护机制可能涉及线粒体钙单向转运体活动及其线粒体通透性转换孔开放的抑制。     

缺氧与血红素氧化酶-1的表达

血红素氧化酶-1(hemeoxygenase1,HO-1)为诱导型血红素氧化酶,是一种急性应激反应蛋白,其催化血红素代谢的产物具有扩张血管和抗氧应激损伤等保护作用。急性缺氧普遍诱导哺乳动物细胞中HO1基因的表达,但在一些人类细胞中,缺氧却抑制HO1的表达,显示出种属、组织和细胞的特异性。缺氧时HO-1的特异性表达可能受细胞内活性氧、MAPK途径以及HIF-1,AP-1和Bach-1等转录因子的调节。     

甘氨酸对缺氧/复氧离体大鼠心脏功能的作用水

目的:观察甘氨酸(glycine,GLY)对缺氧/复氧离体心脏功能的影响,探讨甘氨酸对心肌缺血-再灌注(ischemia/repeffusion,I/R)损伤的防治作用及其机制.方法:利用Langendorff灌流装置复制心肌缺K/复氧(hypoxia/reoxygenation,H/R)模型,观察不同浓度GLY处理后心脏左室收缩压(left ventrieular systolic pressure,LVSP)、左室舒张末压(1eft ventricular end diastolic pressure,LVEDP)、左室发展压(1eft ventricular developed pres-Sure.LVDP=LVSP-LVEDP)、左室收缩压最大上升/下降速率(the maximum rising and dropping rates of left ventrieu-lar pressure,dp/dtmax and dp/dtmin),并在相应的时点分别测定冠脉流出液中的超氧化物歧化酶(superoxide dis-mutase,SOD)活性和丙二醛(malondialdehyde,MDA)的水平.结果:H/R后各时点大鼠心功能各指标均低于缺氧前;GLY处理组复氧后心功能各指标均高于H/R组,并拮抗损伤导致的SOD减少和MDA升高.结论:一定浓度的GLY能显著改善缺氧/复氧心肌的舒缩功能,其机制可能与其提高SOD活性抑制脂质过氧化反应有关.     

改构型酸性成纤维细胞生长因子对离体大鼠缺氧再灌注心脏的保护作用

目的：探讨maFGF对大鼠缺氧再灌注心脏的保护作用及其机制。 方法： 在Langendorff离体心脏灌流装置上建立缺氧再灌注模型，用BL-410生物机能实验系统记录左室发展压（LVDP）、左室内压上升/下降的最大速率（dp/dtmax、dp/dtmin），比较经maFGF和aFGF预处理，心肌缺氧再灌前后LVDP、dp/dtmax、dp/dtmin的变化，测定冠脉流出液中的LDH、MDA、SOD水平。 结果： maFGF和aFGF预处理均明显促进心肌缺氧再灌后心功能恢复，减少缺氧再灌注导致的LDH漏出、SOD降低和MDA升高。 结论： maFGF对缺氧再灌注心脏具有一定的保护作用，其作用机制可能与提高自由基清除酶活性及抑制脂质过氧化反应有关。     

血红素氧合酶-内源性一氧化碳系统对脂多糖性休克大鼠心脏的影响

目的:探讨血红素氧合酶-内源性一氧化碳系统是否对脂多糖性休克大鼠的心脏有保护作用。方法:40只健康清洁级Sprague-Dawley大鼠随机分为4组:①对照(C)组,n=10;②脂多糖性休克(S)组,n=10,10mg/kgE.coli脂多糖(LPS)稀释至0.5mL静脉注射,待其MAP下降至给予LPS前75%时,腹腔内注射1mL50mmol/L碳酸氢钠溶液;③LPS性休克 ZnPP-IX(LZ)组,n=10,休克模型的复制同②,成功后,将10μmol/kgZnPP-IX用50mmol/L碳酸氢钠溶液稀释至1mL腹腔内注射;④ZnPP-IX组(Z)组,n=10,0.5mL0.9%氯化钠溶液静脉内注射,2h后将10μmol/kgZnPP-IX稀释至1mL腹腔内注射。测定各组腹腔内注射碳酸氢钠溶液或ZnPP-IX前及后30min、60min、90min时的LVSP及±dp/dtmax;C组和Z组在静脉内注射氯化钠溶液后6h,S组和LZ组则在静脉内注射LPS6h,检测血中LDH和CK的含量,COHb的浓度及左心室心肌组织内HO-1mRNA、HO-2mRNA及HO-1、HO-2蛋白水平。结果:①LZ组大鼠的LVSP和±dp/dtmax均分别低于S组(P<0.05),其血浆中LDH、CK的含量均分别高于S组(P<0.05);S组大鼠血中COHb水平明显高于LZ组(P<0.05)。②LZ组大鼠其左心室心肌组织内HO-1mRNA表达水平及HO-1蛋白水平明显低于S组(P<0.05);而各组间左心室心肌组织内HO-2mRNA表达水平及HO-2蛋白水平均无显著差异(P>0.05)。结论:脂多糖性休克大鼠其心肌组织内HO-1的上调及随后的CO增加可能对心脏发挥着保护作用。     

甘氨酰谷氨酰胺在大鼠离体心脏缺血/再灌注损伤中的保护作用研究

目的： 研究甘氨酰谷氨酰胺对缺血再灌注大鼠离体心脏的保护作用。方法：应用Langendorff离体心脏灌注系统建立心肌缺血再灌注模型。30只SD雄性大鼠随机分为正常对照组(control)、甘氨酰谷氨酰胺对照组(Gly-Gln)、缺血再灌注组(I/R)、缺血/再灌注+甘氨酰谷氨酰胺组(I/R+ Gly-Gln)。I/R组及I/R+ Gly-Gln组分别灌注30 min后,全心停灌20 min,再灌注40 min,I/R+ Gly-Gln组于再灌注时在灌流液中加入Gly-Gln;正常对照组连续灌流90 min,Gly-Gln对照组灌流液中加入Gly-Gln。记录各组灌注时,左室舒张末压(LVEDP)、左室发展压(LVDP)、左室压力最大变化速率(±dp/dtmax)、心率(HR)及心肌细胞单相动作电位(MAP);同时在相应的时点分别测定冠脉流出液中的乳酸脱氢酶（LDH)、肌酸激酶(CK)活性。结果：离体大鼠心脏缺血20min,再灌注40 min,导致严重的心功能抑制,表现为LVEDP升高,LVDP、±dp/dtmax降低;再灌注液中加入Gly-Gln后,LVEDP降低,LVDP、±dp/dtmax明显升高（P<0.01)。I/R+ Gly-Gln组冠脉流出液中LDH、CK活性明显低于I/R组(均P<0.01)。结论： Gly-Gln能有效减轻缺血再灌注引起的左室功能下降,减少心肌细胞LDH、CK的释出,表明Gly-Gln对缺血再灌注损伤的大鼠离体心脏具有保护作用。     

环氧化酶Ⅱ、神经型一氧化氮合酶介导了心肌缺血预处理延迟性保护作用终末阶段

本研究采用在体家兔冠状动脉阻断的缺血/复灌损伤模型,研究心肌缺血预处理(IP)延迟性保护作用终末阶段(IP后48～72 h),以及神经型一氧化氮合酶(nNOS)、诱生型一氧化氮合酶(iNOS)、环氧化酶Ⅱ(Cyclooxygenase-2, COX-2)是否中介了此过程.研究发现与单纯缺血/复灌组相比,IP后72 h,明显降低心脏缺血/复灌后的梗死面积和血浆中乳酸脱氢酶(LDH) 、6-酮-PGE1a(6-Keto-PGF1α)含量,促进左室收缩压(LVSP)、左室压最大上升速率 (+dP/dtmax)和左室压最大下降速率 (-dP/dtmax)的恢复.使用iNOS的特异性抑制剂S-methylisothiourea sulfate(SMT)不能阻断IP后72 h心肌保护作用.而nNOS的特异性抑制剂N-propyl-L-arginine(NPA),NOS的非特异性抑制剂NG-硝基-L-精氨酸甲酯(L-NAME)、环氧化酶Ⅱ特异性抑制剂塞来昔布(celecoxib,CEL)阻断了IP后72 h的心肌保护作用.结果表明:IP后72 h心肌保护作用依然存在,COX-2、nNOS介导了心肌缺血预处理延迟性保护作用终末阶段,而与iNOS无关.     

血红素氧化酶-1在离体大鼠心肌缺血预处理中的作用

目的：观察缺血预处理对离体大鼠心肌缺血再灌注后心功能、乳酸脱氢酶（LDH）活性和丙二醛（MDA）含量及血红素氧化酶-1活性的影响。方法：应用Langendorff离体大鼠等容收缩灌流模型行离体大鼠心脏灌流。缺血预处理方案为停灌5 min后再灌5 min反复3次,持续缺血再灌方案为停灌40 min后再灌20 min,监测正常对照组、缺血再灌组（IR）和缺血预处理组（IPC）心功能指标的同时,测定冠脉流出液LDH活性、心肌MDA含量和HO-1活性变化。结果：IPC组再灌20 min时的心功能恢复率显著高于IR组（P<0.01）,心肌血红素氧化酶-1活性也明显高于IR组（P<0.05）,而LDH活性及MDA含量显著少于IR组（均为P<0.01）。结论：血红素氧化酶-1活性增高可能与缺血预处理对大鼠缺血再灌心肌的保护作用有关。     

Development in in vitro toxicology

There are three principal pressures driving the development of in vitro toxicology: (1) the need for more efficient testing systems to cope with the large number of xenobiotics currently being developed; (2) public pressure to reduce animal experimentation; and (3) a need for a better understanding of the mechanisms of toxicity. Within this, in vitro toxicology is focused on local, systemic, and target-organ toxicity. It is becoming increasingly apparent that a step or decision-tree approach using input of a variety of experimental data (physicochemical properties, biokinetics, cytotoxicity) provides the most efficient system for predicting toxicity. Examples of the use of in vitro toxicity systems for prediction of systemic toxicity and target-organ (liver) toxicity are presented.Originally presented at ECCP 93.     

Seasonal variations in acute toxoplasmosis in pregnant women in Slovenia

Between December 1999 and December 2004, 40 081 pregnant women were examined for toxoplasmosis with Toxo-IgG, Toxo-IgM enzyme immunoassay. Women with positive results were then retested with the Toxo-IgG avidity assay for recent toxoplasmosis. Recent acute toxoplasmosis in pregnant women was found to be significantly more frequent (p < 0.01) during winter than summer. The incidence of acute toxoplasmosis during winter-spring was also significantly more frequent (p < 0.025) than summer-autumn. This phenomenon should be taken into account when formulating preventive measures for toxoplasmosis, especially for pregnant women.     

Age-related changes in polyamines in memory-associated brain structures in rats

Polyamines putrescine, spermidine and spermine are positively charged aliphatic amines and have important roles in maintaining normal cellular function, regulating neurotransmitter receptors and modulating learning and memory. Recent evidence suggests a role of putrescine in hippocampal neurogenesis, that is significantly impaired during aging. The present study measured the polyamine levels in memory-related brain structures in 24- (aged), 12- (middle-aged) and 4- (young) month-old rats using liquid chromatography/mass spectrometry and high performance liquid chromatography. In the hippocampus, the putrescine levels were significantly decreased in the CA1 and dentate gyrus, and increased in the CA2/3 with age. Significant age-related increases in the spermidine levels were found in the CA1 and CA2/3. There was no difference between groups in spermine in any sub-regions examined. In the parahippocampal region, increased putrescine level with age was observed in the entorhinal cortex, and age did not alter the spermidine levels. The spermine level was significantly decreased in the perirhinal cortex and increased in the postrhinal cortex with age. In the prefrontal cortex, there was age-related decrease in putrescine, and the spermidine and spermine levels were significantly increased with age. This study, for the first time, demonstrates age-related region-specific changes in polyamines in memory-associated structures, suggesting that polyamine system dysfunction may potentially contribute to aged-related impairments in hippocampal neurogenesis and learning and memory.     

休克过程中肾上腺髓质素变化的研究进展

Adrenomedullin (AM) is a new peptidergic regulator of vascular function. AM serves as a hormone, which has many biological properties, plays an important role in the many pathophysiological processes, especially shock. This review will highlight the structure, biological properties of AM and the relationship between AM and shock.     

Secular change in menarche in women in Madrid

The age at menarche was estimated by recollection in 1617 women between the ages of 18 and 60 in Madrid and a nearby suburb, Pinto. The population of Pinto is working-class and the Madrid group, taken from residential neighbourhoods , belongs to the upper middle class. In both groups we found a diminution in average age at menarche, from 14.04 to 13.02 years in Madrid and from 14.55 to 13.16 years from about 1935 to about 1965 in Pinto. These changes have been more intense in the group which is less well-off economically, where living conditions have varied much more drastically.     

Pitfalls in TRAP assay in routine detection of malignancy in effusions

Telomerase has been found to be reactivated in a majority of cancers but is inactive in most somatic cells. Our principal goal was to determine the potential use of the telomeric repeat amplification protocol (TRAP) assay as marker for malignancy in cytological effusions. The simple selection criterion was the cytological diagnosis, and routine samples were classified into malignant (58 samples) and nonmalignant (233 samples). Of the malignant samples, 44/58 (76%) were positive by TRAP assay. Of the 14 telomerase-negative cytology-positive samples, RNA integrity was poor in 9, indicating suboptimal sample conservation for molecular analysis. In 3 of the remaining 5 samples with a negative TRAP assay, a high number of malignant cells was observed, and these cells might have been telomerase-negative. Thus, the sensitivity of TRAP assay for the presence of malignant cells was about 76%. In the cytologically nonmalignant effusions, the presence of telomerase activity was observed in 24% (55/233). Of these, 6% were highly suspicious for malignancy, 9% were doubtful, and 9% were cytologically nonmalignant effusions confirmed by a follow-up of 12 mo or more. According to these data, the specificity of the TRAP assay to detect tumor cells in effusions ranged only between 82-91%. Our results indicate that, although the TRAP assay is positive in 6-15% of putative malignant effusions, the relatively high number of TRAP false-negative and false-positive cases renders this test unsuitable for routine diagnostic purposes.