异丙酚对大鼠脑缺血再灌注海马细胞周期因子变化及神经元凋亡的影响

目的： 探讨大鼠局灶性脑缺血再灌注后海马神经元细胞周期蛋白1（cyclin D1）和细胞周期蛋白依赖性蛋白激酶4（cyclin-dependent kinase 4,CDK4）的表达与神经元凋亡的关系及异丙酚的脑保护作用。方法: 采用大脑中动脉内栓线阻断法（middle cerebral artery obstruction,MCAO）造成局灶性脑缺血再灌注模型。用免疫印迹法（Western blotting）观察cyclin D1和CDK4蛋白的表达;采用流式细胞仪检测海马神经元凋亡。再灌注48 h时进行大鼠神经功能缺陷比较。结果: （1）异丙酚可以改善大鼠脑缺血再灌注后的神经功能缺陷（P＜0.01）;（2）与假手术组比较,脑缺血再灌注48 h后缺血侧海马神经元cyclin D1、CDK4表达明显升高、凋亡细胞数明显增多（P＜0.01）。与缺血再灌注组比较,异丙酚组海马神经元cyclin D1、CDK4的表达和凋亡率明显降低（P＜0.05）。结论: 脑缺血再灌注后缺血侧海马cyclin D1、CDK4表达增强,这可能是介导脑缺血再灌注后神经元凋亡的机制之一;异丙酚可下调神经元cyclin D1、CDK4的表达,抑制神经元凋亡,减轻缺血再灌注对大鼠海马神经元的损伤。     

银杏叶提取物对局灶性脑缺血再灌注后GFAP表达的影响

目的研究银杏叶提取物(extract of Ginkgo biloba,EGB)对局灶性脑缺血再灌注后星形胶质细胞胶质纤维酸性蛋白(GFAP)表达的影响。方法大脑中动脉插线法制作大鼠局灶性脑缺血再灌注模型。75只Wistar大鼠随机分为假手术组、缺血再灌注组、EGB治疗组。缺血2h再灌注48h后,采用免疫组织化学法检测脑组织内GFAP蛋白的表达。结果缺血再灌注后可诱导脑组织GFAP表达增强,EGB可抑制缺血再灌注后GFAP的表达(P<0.05)。结论局灶性脑缺血再灌注后,可诱导脑组织GFAP表达增强,EGB可抑制脑缺血后星形胶质细胞GFAP的高表达,提示EGB可能对缺血诱导的星形胶质细胞活化具有抑制作用,这可能是EGB抗脑缺血损伤保护神经元作用的机制之一。     

局灶性脑缺血再灌注时神经元、胶质细胞形态变化与TNF-α、c-Myc表达相关的实验研究

目的:探讨局灶性脑缺血再灌注时神经元、神经胶质细胞形态变化特点和TNF-α、c-Myc表达的相关性。方法: 采用线栓法大鼠大脑中动脉阻塞复制局部脑缺血再灌注模型,缺血2 h分别再灌注1 d、3 d、7 d,应用光镜和免疫组化法,观察缺血侧额顶叶皮质神经元,神经胶质细胞形态变化及TNF-α、c-Myc蛋白表达。结果: 局灶性脑缺血再灌注后,同侧额顶叶皮质梗死区神经元、小胶质细胞、星形胶质细胞出现变性、坏死,梗死灶周围小胶质细胞和星形胶质细胞增生,呈现时间相关性,变性、死亡以再灌注3 d最为显著,星形胶质细胞和小胶质细胞增生以再灌注7 d最为显著且位于梗死周围区。再灌注后,TNF-α、c-Myc阳性细胞表达也显著增加,以再灌注3 d最为显著,且主要表达于星形胶质细胞、小胶质细胞,少量表达于神经元。结论: 脑缺血再灌注后神经元、神经胶质细胞之间在损伤、抗损伤及修复中相互影响,而TNF-α、c-Myc蛋白表达的增加可能是联系不同细胞间相互作用的主要调节物质之一。     

磷酸化的细胞周期相关蛋白在大鼠海马神经元发育和老化过程中的表达

目的： 观察正常Wistar大鼠发育及老化过程中海马神经元磷酸化的细胞周期相关蛋白的表达,探讨这一过程中海马神经元的细胞周期的变化以及磷酸化细胞周期相关蛋白在其中的调控作用。方法：采用免疫荧光方法观察不同发育时期(1天、11天、1月、3月、15月) 磷酸化周期素依赖激酶2（CDK2）、磷酸化细胞分裂周期激酶2（CDC2）、磷酸化视网膜母细胞瘤（Rb）蛋白表达的规律,并应用Western blotting方法测定不同阶段大鼠海马内磷酸化CDK2、磷酸化CDC2、磷酸化Rb的含量。结果：在各年龄组中神经元特异性核蛋白（NeuN）阳性细胞数量随着年龄增加而逐渐减少,提示神经元数量随年龄的增加而逐渐减少。磷酸化CDK2、磷酸化Rb阳性细胞的数量随着年龄增加而逐渐增多,老年组增加明显,与其它各组间有显著差异,磷酸化CDC2阳性细胞在各年龄组神经元中表达量均较低;蛋白定量亦提示老年组磷酸化CDK2、磷酸化Rb的含量较其它组明显增高。结论：海马神经元数量随年龄增加逐渐减少,而其中磷酸化CDK2和磷酸化Rb却随年龄的增长逐渐增多,提示老化过程中部分神经元再次进入细胞周期,说明磷酸化细胞周期相关蛋白可能参与了这一过程中海马神经元的凋亡。     

银杏叶提取物对局灶性脑缺血再灌注不同时段的大鼠脑组织GFAP的影响

目的观察银杏叶提取物(extract of Ginkgo biloba,EGB)对大鼠局灶性脑缺血再灌注梗死区胶质纤维酸性蛋白(GFAP)表达的影响。方法采用改良线栓法建立大鼠大脑中动脉阻塞脑缺血再灌注模型。观察再灌注1～4d里大鼠神经功能缺损程度并应用免疫组织化学法、Metamoph图像分析系统对结果进行分析。结果EGB药物组神经功能评分较缺血再灌组好(P<0.05),GFAP阳性细胞于脑缺血2h再灌注24h后即已出现,48、72、96h阳性细胞表达量增加,其中以72h为最多,EGB可抑制缺血后GFAP的表达(P<0.05)。结论局灶性脑缺血后可诱导脑组织GFAP表达增强,EGB可抑制脑缺血再灌注后星形胶质细胞GFAP的高表达,提示EGB对缺血诱导的星形胶质细胞活化具有抑制作用,可能对脑缺血损伤的恢复起重要作用。     

CGRP对局灶性脑缺血再灌注大鼠顶叶皮质CREB和p-CREB的上调作用

目的：探讨外源性降钙素基因相关肽（CGRP）对局灶性脑缺血再灌注大鼠顶叶皮质CREB和磷酸化CREB（p-CREB）表达的影响。方法:用线栓法阻塞大鼠右大脑中动脉制作局灶性脑缺血再灌注模型，应用免疫组织化学、Western blotting和图像分析方法检测大鼠手术侧顶叶皮质CREB和p-CREB表达。结果:缺血再灌注组大鼠顶叶皮质CREB表达少于假手术组，CGRP组大鼠顶叶皮质CREB表达多于缺血再灌注组（P<0.05）。假手术组右侧顶叶皮质p-CREB表达很少，缺血再灌注组顶叶皮质p-CREB表达多于假手术组，CGRP组p-CREB表达多于缺血再灌注组（P<0.05）。结论:CGRP上调局灶性脑缺血再灌注大鼠右侧顶叶皮质CREB和p-CREB的表达，CGRP对缺血神经元的保护作用可能是通过上调神经元内CREB和p-CREB来实现的。     

川芎嗪对大鼠脑缺血再灌注损伤后GFAP表达和脑组织水肿的影响

探讨川芎嗪对大鼠脑缺血再灌注损伤后星形胶质细胞表达胶质原纤维酸性蛋白(GFAP)以及对脑组织含水量的影响。将70只SD大鼠随机分为3组:脑缺血后1、3、5、7、10d模型组(n=30,每个时间点用6只)、川芎嗪预处理组(n=30,每个时间点用6只)和假手术组(n=10,每个时间点用2只)。采用线栓法制作大鼠局灶性脑缺血再灌注模型(MCAO),应用免疫组化法观察星形胶质细胞GFAP的表达,干湿重法测定脑组织的含水量。结果显示:川芎嗪预处理组大鼠各时间点海马CA1区的GFAP阳性细胞数量显著增多,与缺血模型组比较均有显著性差异(P<0.05)。缺血再灌注后脑组织含水量持续性增加,到3d达到最高峰,5d时仍较高,以后逐渐降低;川芎嗪组各时间点的脑组织含水量均低于缺血模型组(P<0.05)。上述研究结果提示川芎嗪可引起星形胶质细胞活化、保护神经元、减轻脑水肿,具有防治脑缺血再灌注损伤的作用。     

局灶性脑缺血后鼠脑组织tPA基因表达及其与细胞凋亡

目的 探讨局灶性脑缺血后组织型纤溶酶原激活物（tＰＡ）基因的表达及其与细胞凋亡的 关系。方法 用原位杂交和免疫组织化学方法检测tＰＡ基因在大鼠局灶性脑缺血（大脑中 动脉阻塞）后的表达,用ＴＵＮＥＬ法检测缺血不同时间的细胞凋亡状况。结果 脑缺血６h缺血中心部位的胶质细胞和梗死灶周边缺血半影区的神经元均观察到tＰＡ免疫反应性信号,在大脑皮层后肢体区、顶皮层区、海马区和齿状回可见凋亡细胞,但缺血１８h缺血侧神     

肢体远程缺血后处理促进局灶性脑缺血再灌注大鼠皮质区热休克蛋白70的表达

目的　观察肢体远程缺血后处理（LRIP）对局灶性脑缺血再灌注损伤大鼠皮质梗死区周围神经元、血管内皮细胞以及星形胶质细胞热休克蛋白70（Hsp70）的表达变化,探讨LRIP发挥脑保护作用的可能分子机制。方法　健康成年SD大鼠,随机分为假手术组（sham）、局灶性脑缺血再灌注模型组（I/R）、LRIP组。实验采用线栓法建立局灶性大脑中动脉脑缺血(1h)再灌注模型(MCAO),大鼠脑缺血再灌注即刻行双下肢股动脉橡皮筋结扎10min,放松10min,重复3次建立LRIP组模型。于再灌注1d、3d分别断头取脑,Zea longa评分作为判断MCAO模型成功的标准,Garcia神经行为学评分方法检测大鼠神经损伤程度,TTC检测脑梗死体积,Western blotting检测Hsp70蛋白表达含量, 免疫组织化学和免疫荧光技术,用于检测皮质梗死区周围Hsp70阳性表达细胞的数目、部位以及类型。结果　应用LRIP后,LRIP组与I/R组比较,神经行为学评分明显增加（P<0.05）、脑梗死体积显著降低（P<0.05）,Hsp70蛋白表达明显增加,其中1d组无统计学意义（P>0.05）,3d组有显著统计学意义（P<0.01）,Hsp70阳性表达主要在梗死区周围神经元、血管内皮细胞和星形胶质细胞突起。结论　LRIP可明显改善脑缺血后神经行为学功能、降低脑梗死体积,根据本实验结果我们推测此作用可能与LRIP上调皮质梗死区周围神经元、血管内皮细胞和星形胶质细胞Hsp70表达有关。     

巴曲酶对脑缺血再灌注大鼠海马CA1区的影响

目的 通过观察大鼠局灶性脑缺血再灌注不同时段，巴曲酶对海马CAl神经元及星形胶质细胞数目、形态等方面的影响，从而探讨巴曲酶对局灶性脑缺血再灌注损伤的保护作用。方法 采用改良的线栓法制备大脑中动脉阻塞(MACO)2h、不同再灌注时间段(3h、6h、12h、24h、48h、72h、7d)的大鼠短暂局灶性脑缺血(transient focal cerebral isehemia)模型，随机设立巴曲酶组(Bat)、生理盐水对照组(N．S)、假手术组(sham-operated)，通过HE染色及胶质原纤维酸性蛋白(GFAP)和神经元特异核抗原(NeuN)的免疫组化染色，观测CAl区神经元和星形胶质细胞的形态、数目的动态变化。结果巴曲酶能显提高再灌注早期(6～24h)CAl区GFAP阳性细胞的数目，再灌注7d组存活锥体细胞的数量较盐水对照组有明显提高，提示局灶性脑缺血后早期反应性星形胶质细胞的增多对维持神经元的存活有积极意义，巴曲酶对短暂局灶性脑缺血再灌注引起的海马CAl区延迟性神经元坏死(DND)有一定的抑制作用。     

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.