一种新型高脂血症易感大鼠的血脂水平与心血管并发症

目的观察一种新型高脂血症易感WSHc大鼠经高脂饲料诱导后血脂的动态变化和心血管并发症病理特点,为WSHc大鼠的应用提供参考。方法取7～8周龄雌性WSHc大鼠20只和Wistar大鼠10只,进行高脂饲喂,另取同周龄同性别的WSHc大鼠和Wistar大鼠各10只饲喂普通饲料,分别作为正常对照。观察高脂饲喂2、4、8、12、16周时的血脂动态变化,饲喂16周后采用心动超声检测大鼠心功能及左心结构,病理组织学观察心脏及主动脉病变。结果与正常对照组比,高脂饲喂2周后WSHc大鼠与Wistar大鼠血清总胆固醇(TC)与低密度脂蛋白胆固醇(LDL-c)均显著升高;高脂饲喂的WSHc大鼠TC、LDL-c水平为:(6.34±2.12)mmol/L、(2.56±0.94)mmol/L,而高脂饲喂的Wistar大鼠TC、LDL-c水平仅为(2.93±0.23)mmol/L,(0.63±0.12)mmol/L;在高脂饲喂期间,WSHc大鼠TC始终维持在高水平状态。饲喂16周后,WSHc大鼠心脏射血分数升高,左心室室壁增厚,并出现心肌纤维化,心肌细胞凋亡程度增高;主动脉内膜增厚,弹力纤维排列紊乱,形成早期动脉粥样硬化病变。而Wistar大鼠经高脂饲料诱导后,心功能及心血管病变不明显。结论 WSHc大鼠对外源性胆固醇敏感,高脂饲喂后易发高脂血症及心血管疾病,且TC、LDL-c水平与临床高脂血症更接近,相较于普通大鼠,更适用于高脂血症及相关心血管并发症的实验研究。     

SDF-1α inhibits hypoxia and serum deprivation-induced apoptosis in mesenchymal stem cells through PI3K/Akt and ERK1/2 signaling pathways

Bone marrow-derived mesenchymal stem cells (BMSCs) have been demonstrated to be a promising cell sources for cardiac regeneration. Poor survival rate of transplanted BMSCs in infarcted myocardium attenuated its clinical application. It’s reported that stromal-derived factor-1 (SDF-1) could protect progenitor cells including endothelial progenitor cells and embryonic stem cells from apoptosis. But little is known whether SDF-1α protein has the same protective effects on BMSCs under conditions of hypoxia and serum deprivation (hypoxia/SD). In present study, we verified that SDF-1α (0.50–2.0 μg/ml) inhibited hypoxia/SD induced apoptosis of BMSCs through mitochondrial pathway. After administration of SDF-1α, the loss of mitochondrial membrane potential and cytochrome c released from mitochondria to cytosol were significantly inhibited, and caspase 3 activity also declined. Furthermore, the effect of SDF-1α on mitochondrial pathway was neutralized by using PI3K inhibitor (Wortmannin) and ERK1/2 inhibitor (U0126). Our observations suggested that SDF-1α inhibits hypoxia/SD induced BMSCs apoptosis through PI3K/Akt and ERK1/2 signaling pathways. These data also imply that the anti-apoptotic effect mediated by SDF-1α may enhance cell survival after cell transplantation.     

A novel peptide isolated from a phage display peptide library with trastuzumab can mimic antigen epitope of HER-2

Trastuzumab, a humanized antibody to HER-2, has been shown to be effective in the treatment of breast cancer in which HER-2 overexpression and metastasis occurs. In our search for an effective mimic epitope of HER-2 binding with trastuzumab and to develop HER-2 peptide vaccine, we screened a phage display 12-mer peptide library with trastuzumab as the target. A mimetic peptide (mimotope) H98 (LLGPYELWELSH) that could specifically recognize trastuzumab was isolated. The DNA encoding peptide H98 was cloned and expressed as the fusion protein GST-H98 in Escherichia coli BL21. The purified GST-H98 could specifically bind to trastuzumab and block the binding of trastuzumab to HER-2 protein. Moreover, H98 could significantly block the function of trastuzumab inhibiting the growth of cancer cells. Mice that were immunized with GST-H98 made specific antibody to H98 as well as to HER-2. In addition, T-cell proliferation occurred in mice immunized with GST-H98. Although no sequence homology was found between H98 and HER-2, through the use of structure analysis we were able to determine that peptide H98 contributed to a conformational epitope of HER-2. Furthermore, we determined that the last two amino acids at the C terminus, and the third together with the fourth amino acid at the N terminus of peptide H98 are critical to the binding of H98 to trastuzumab. As a result, we conclude that peptide H98 has potential for being developed as a HER-2 vaccine for biotherapy of cancer with HER-2 overexpression.     

细胞周期因子与植物根系发育

植物根系的发育是一个非常复杂且被精确调控的过程,受到多种信号的调控,其中对细胞分裂水平调控的研究已经成为细胞生物学研究的热点之一.文章介绍了植物细胞周期因子和植物根系发育相关的细胞周期调控机制以及根系细胞周期激素调节的研究进展.     

宁波大榭开发区北岸潮间带春季大型底栖动物群落格局

为了解宁波大榭岛潮间带春季大型底栖动物群落结构与数量分布,探讨自然环境因子和人类活动对潮间带大型底栖动物种类组成及数量分布的影响,于2006年4月对大榭岛北岸岩礁相和泥沙相两种不同底质的潮间带大型底栖动物进行采样分析.研究表明:(1)岩礁相断面和泥沙相断面共发现大型底栖动物39种,其中贝类20种,多毛类8种,甲壳类8种;(2)岩礁相断面19种,主要以贝类生物为主,达16种,甲壳类只有2种;泥沙相断面20种,贝类、多毛类和甲壳类分布较为均匀,分别为4种、6种和8种;(3)岩礁相断面和泥沙相断面平均栖息密度分别为583.33 ind/m2和32 ind/m2,平均生物量分别为638.56 g/m2和7.83 g/m2,岩礁相断面栖息密度和生物量均远高于泥沙相断面;(4)岩礁相断面大型底栖动物群落垂直变化较泥沙相断面显著.     

两种桡足类短期热冲击的高起始致死温度值

于2007年4月研究了亚热带海域近海种桡足类中华哲水蚤(Calanus sinicus Brodsky)和真刺唇角水蚤(Labidocera euchaeta Giesbrecht)在不同驯化温度下热冲击15、30、45 min后的24 h高起始致死温度(upper incipient lethal temperature,24-h UILT50).结果表明:(1)在相同驯化温度下,两种桡足类短期热冲击24-h UILT50随暴露时间的延长而降低;(2)在相同暴露时间下,两种桡足类短期热冲击24-h UILT50随驯化温度的上升均有不同程度的上升,但这种升高的趋势会随驯化温度的上升而变缓,且趋于一固定值后不再上升;(3)中华哲水蚤在暴露时间为15、30、45 min的24 h最高起始致死温度(ultimate upper incipient lethal temperature,24-h UUILT50)分别为31.7、31.0、30.3℃,真刺唇角水蚤在暴露15、30、45 min时的24-h UUILT50分别为36.5、36.0、35.4℃;(4)在相同驯化温度和暴露时间条件下,真刺唇角水蚤对短期热冲击的耐受性显著强于中华哲水蚤.     

壳聚糖/海藻酸钠微囊在中药提取物缓释制剂中的应用

壳聚糖/海藻酸钠生物微胶囊作为一个优良的缓释给药系统,具有良好的生物相容性和机械强度,原料易得、价格便宜,制备工艺简单且可工业化生产而倍受国内外从事生物微胶囊研究的学者关注.本文综述了壳聚糖和海藻酸钠的理化性质、生物微胶囊制备原理和方法以及其在中药提取物缓释制剂中的应用.     

鲜姜化学成分的GC—MS分析

本文采用鲜姜榨汁-过滤的方法提取鲜姜内成分。然后对其化学成分进行GC／MS分析。从鲜姜汁中分离确定了33中成分,其中萜类物质相对含量较高。     

不同季节温升条件下余氯对桡足类的毒性

为探明桡足类对滨海电厂冷却水中余氯的忍受能力,在各季节于室内对采自乐清湾的12种桡足类进行30 min不同升温幅度(△T)(0、4.0、8.0、12.0℃)下的余氯胁迫,观察桡足类在24h后的死亡率,用概率单位法计算其余氯半致死浓度(Median lethal concentration,LC50).结果表明各季节桡足类余氯LC50随△T增大而显著降低(P＜0.001),且.多数种类呈显著线性回归关系(P＜0.05).对于哲水蚤目桡足类,余氯LC50随其粒径增大而升高.同一种桡足类在相同△T下,随适应水温升高,余氯LC50显著降低(P＜0.01).亚热带海区夏季自然水温较高,冷却系统轻微的升温即可加剧余氯对其的毒性.若以LC50×0.5来确定桡足类余氯安全浓度,则春、秋、冬季暴露时间≤30 min、△T≤12.0℃时,其余氯安全浓度分别为0.21-0.86 mg/L、0.26-0.86 mg/L、0.32-4.55 mg/L;夏季暴露时间≤30 min、△T≤8.0℃时,其余氯安全浓度为0.15-0.41 mg/L.当前电厂加氯浓度偏高对冷却水中桡足类造成较大影响,但排出水中余氯对其影响不大.基于生态安全考虑,根据对余氯较敏感的小型桡足类在不同季节下的余氯安全浓度,建议亚热带滨海电厂夏季余氯排放浓度不超过0.15 mg/L,其余季节不超过0.20 mg/L.