基于荧光分子断层成像的多模成像系统研究进展

基于荧光分子断层成像（FMT）的多模成像系统已广泛应用于动物实验研究,它将现有的其他成像模态与FMT系统相融合,实现同时对被测生物解剖学结构、生理学功能和分子或细胞水平生物学活动的在体成像.首先介绍了单模FMT系统的发展历史和现状,并介绍了国内外基于FMT的多模系统的研究进展,着重介绍了文献报道的典型的FMT/CT、FMT/MRI和FMT/放射性核素成像系统的系统组成、工作原理、性能特点及实验应用.对基于FMT的多模成像系统的发展进行了展望.     

Feedback inhibition of action potential discharge by endogenous adenosine enhancement of the medium afterhyperpolarization

Phasic activity in supraoptic nucleus vasopressin neurones is characterized by alternating periods of activity (bursts) and silence. During bursts, activation of a medium afterhyperpolarization induces spike frequency adaptation. Antagonism of A1 adenosine receptors within the supraoptic nucleus decreases spike frequency adaptation and prolongs phasic bursts in vivo , indicating that endogenous adenosine contributes to spike frequency adaptation. Here we used sharp electrode intracellular recordings from supraoptic nucleus neurones in hypothalamic explants to show that endogenous adenosine increases medium afterhyperpolarization amplitude to enhance spike frequency adaptation during phasic bursts. Superfusion of the A1 receptor antagonist 8-cyclopentyl-1,3-dimethylxanthine (CPT, 10 μ m ) increased intraburst firing rate of phasic neurones (by 2.0 ± 0.7 spikes s⁻¹, P = 0.03) and burst duration (by 141 ± 113 s, P = 0.03). The CPT-induced increase in intraburst firing rate developed over the first few seconds of firing and persisted thereafter. In a separate series of experiments, CPT reduced the amplitude of the medium afterhyperpolarization evoked by a 1 s 20 Hz spike train (by 0.8 ± 0.3 mV, P < 0.001) in supraoptic nucleus neurones; this inhibition was not prevented by 3 m m CsCl (0.8 ± 0.1 mV decrease, P < 0.01) to block the afterdepolarization (which overlaps temporally with the medium afterhyperpolarization). In the presence of apamin to block the medium afterhyperpolarization, CPT did not alter afterdepolarization amplitude. Taken together, these data show that endogenous adenosine enhances medium afterhyperpolarization amplitude to contribute to spike frequency adaptation in phasic supraoptic nucleus neurones.     

Prediction of function changes associated with single‐point protein mutations using support vector machines (SVMs)

Computational methods can be used to predict the effects of single amino acid substitutions (single‐point mutations). In contrast to previous methods that need many protein sequence and structural features, we applied support vector machines (SVMs) to predict protein function changes associated with amino acid substitutions using only sequence information, and cross‐validated them on a large dataset extracted from the Protein Mutant Database (PMD). By three SVM classifiers, we investigated three local sequence features of proteins (residue composition, hydrophobic interaction, and evolutionary property), and examined their effects on the prediction accuracy. As a main result, a novel SVM named substitution‐matrix‐based kernel SVM was constructed to make speedy and accurate prediction, and its value was shown in an application case. Furthermore, our findings confirmed results from other studies. Hum Mutat 30,1–6, 2009. © 2009 Wiley‐Liss, Inc.     

The effect of quantum dots on synaptic transmission and plasticity in the hippocampal dentate gyrus area of anesthetized rats

Recently, quantum dots (QDs) have attracted widespread interest in biology and medicine. They are rapidly being used as new tools for both diagnostic and therapeutic purposes. Critical issues for further applications of QDs include the assessment of biocompatibility and biosafety of QDs. Most of previous researches concerning QD cytotoxicity focused on in vitro studies. In the present study, the impairments of acute exposure to well-modified and unmodified QDs (streptavidin-CdSe/ZnS and CdSe QDs, respectively) on synaptic transmission and plasticity were examined in adult rat hippocampal dentate gyrus (DG) area in vivo. The input/output (I/O) functions, paired-pulse ratio (PPR), field excitatory postsynaptic potential (fEPSP) and population spike (PS) amplitude were measured. The results showed that PPR and long-term potentiation (LTP) were all significantly decreased in these two types of QD-exposed rats compared to those in control rats. While the I/O functions and the amplitudes of fEPSP slope and PS amplitude of the baseline were significantly increased under QD exposure. These findings suggest that exposure to QDs, no matter whether they are well modified or not, could impair synaptic transmission and plasticity in the rat DG area in vivo and reveal the potential risks of QD applications in biology and medicine, especially in the toxin-susceptible central nervous system (CNS).     

分娩疼痛程度及其相关因素与分娩结局

目的 评估分娩疼痛程度及其相关因素与分娩结局.方法 选择2009年7-12月在浙江中医药大学附属第二医院住院分娩的正常单胎头位产妇111例,其中高龄产妇5例,采用视觉模拟评分( VAS)法评估潜伏期、活跃期疼痛程度;评估疼痛相关因素包括孕妇年龄、孕次、产次、职业、文化程度、居住地等.自行设计调查问卷,由经过培训的专业人员分别对孕妇进行分娩认知、分娩的心理准备、情绪控制能力、夫妻感情、婆媳关系、与父母关系、家庭经济状况的评估,记录产程中镇静剂的应用情况,统计分娩结局.结果 (1)疼痛相关因素:潜伏期:高龄产妇中度疼痛发生率(1/5)明显低于适龄产妇(76.4％,81/106);对分娩认知良好的产妇中度疼痛发生率(64.7％,44/68)低于认知不足的产妇(88.4％,38/43);夫妻感情良好的产妇中度疼痛发生率(77.2％,78/101)明显高于感情一般的产妇(4/10);经产妇中度疼痛发生率明显低于初产妇,上述各项比较,差异均有统计学意义(P＜0.05).活跃期:进入活跃期的产妇共106例,其中对分娩的心理准备充分者重度疼痛发生率(35.6％,16/45)明显低于对分娩紧张和恐惧者(59.0％,36/61);情绪控制能力良好的产妇重度疼痛发生率(44.8％,43/96)低于情绪控制不良的产妇(9/10);应用镇静剂的产妇重度疼痛发生率(29.2％,7/24)低于未用镇静剂的产妇(54.9％,45/82),上述各项比较,差异也均有统计学意义(P＜0.05).(2)分娩结局:潜伏期中度疼痛者胎儿窘迫发生率(36.6％,30/82)、剖宫产率(39.0％,32/82)均显著高于轻度疼痛者(13.8％,4/29和17.2％,5/29),活跃期重度疼痛者胎儿窘迫发生率(36.5％,19/52)、剖宫产率(40.4％,21/52)、产后出血发生率(13.5％,7/52)均显著高于中度疼痛者[分别为18.5％ (10/54)、20.4％ (11/54)和0],差异均有统计学意义(P＜0.05).结论 对分娩认知不良、紧张和恐惧、情绪控制能力差、年轻、初产妇分娩疼痛剧烈;活跃期应用镇静剂可以减轻分娩疼痛;自觉疼痛程度轻的产妇分娩结局好.     

Multiepitope Fusion Antigen Induces Broadly Protective Antibodies That Prevent Adherence of Escherichia coli Strains Expressing Colonization Factor Antigen I (CFA/I), CFA/II,and CFA/IV

Diarrhea is the second leading cause of death in children younger than 5 years and continues to be a major threat to global health. Enterotoxigenic Escherichia coli (ETEC) strains are the most common bacteria causing diarrhea in developing countries. ETEC strains are able to attach to host small intestinal epithelial cells by using bacterial colonization factor antigen (CFA) adhesins. This attachment helps to initiate the diarrheal disease. Vaccines that induce antiadhesin immunity to block adherence of ETEC strains that express immunologically heterogeneous CFA adhesins are expected to protect against ETEC diarrhea. In this study, we created a CFA multiepitope fusion antigen (MEFA) carrying representative epitopes of CFA/I, CFA/II (CS1, CS2, and CS3), and CFA/IV (CS4, CS5, and CS6), examined its immunogenicity in mice, and assessed the potential of this MEFA as an antiadhesin vaccine against ETEC. Mice intraperitoneally immunized with this CFA MEFA exhibited no adverse effects and developed immune responses to CFA/I, CFA/II, and CFA/IV adhesins. Moreover, after incubation with serum of the immunized mice, ETEC or E. coli strains expressing CFA/I, CFA/II, or CFA/IV adhesins were significantly inhibited in adherence to Caco-2 cells. Our results indicated this CFA MEFA elicited antibodies that not only cross-reacted to CFA/I, CFA/II and CFA/IV adhesins but also broadly inhibited adherence of E. coli strains expressing these seven adhesins and suggested that this CFA MEFA could be a candidate to induce broad-spectrum antiadhesin protection against ETEC diarrhea. Additionally, this antigen construction approach (creating an MEFA) may be generally used in vaccine development against heterogenic pathogens.     

Behandlung der vaginalen Atrophie mit einer Kombination von Östriol und Laktobazillen

In den letzten Jahren wurde eine große Zahl von Studien zur Pathophysiologie der symptomatischen vulvovaginalen Atrophie (VVA) bzw. des urogenitalen Menopausesyndroms („genitourinary syndrome of menopause“ [GSM]) bei peri- und postmenopausalen Frauen und zu den Behandlungsmöglichkeiten für diese Zustände publiziert. Die Leitlinien verschiedener Gesellschaften wurden im Bereich der vaginalen Therapie von VVA/GSM aktualisiert. In diesen wird die vaginale Gabe von Östrogenen favorisiert. Die Kombination einer ultraniedrigen vaginalen Dosis von 0,03 mg Östriol (E3) und lyophilisiertem, lebensfähigem Lactobacillus acidophilus KS400 (0,03 mg E3/L) entspricht einem Produkt mit dualem Wirkmechanismus, der nicht nur die Proliferation und Reifung des Vaginalepithels, sondern auch die Wiederherstellung der laktobazillären Mikroflora fördert. Es ist hinreichend belegt, dass die Kombination ein gesundes vaginales Ökosystem schafft und aufrechterhält. Die Anwendung verbessert die klinischen Anzeichen und Symptome sowie die Lebensqualität menopausaler Frauen, die an vaginaler Atrophie leiden, erheblich. Die Kombinationstherapie ist gut verträglich, mit einer niedrigen Gesamthäufigkeit von Nebenwirkungen und einer vernachlässigbaren systemischen Östriolresorption. Basierend auf jüngsten wissenschaftlichen Erkenntnissen und den aktuellen Behandlungsleitlinien kann die 0,03 mg-E3/L-Kombination als eine Behandlungsoption für die symptomatische vaginale Atrophie bei peri- und postmenopausalen Frauen in Betracht gezogen werden.     

Pentraxin 3 promotes oxLDL uptake and inhibits cholesterol efflux from macrophage-derived foam cells

Background

The objective of this study was to determine the effects of pentraxin3 (PTX3) on human oxidized low density lipoprotein (oxLDL) uptake and cholesterol efflux from human macrophage foam cells, which may play a critical role in atherogenesis.

Methods

The effects of PTX3 on oxLDL uptake and cholesterol efflux were determined after transfection of human THP-1 macrophages with pSG5hPTX3 or PTX3siRNA plasmids. To evaluate the role of specific signaling pathways, human THP-1 cells were pre-treated with inhibitors of the extracellular signal-regulated protein kinases 1 and 2 (ERK1/2), phosphatidylinositide 3-kinases (PI3-K), and p38 mitogen-activated protein kinase (MAPK) pathways (PD98059, LY294002, and SB203580, respectively), and then exposed to oxLDL for the uptake assay or oxLDL and [³H]-cholesterol and apolipoprotein A-I (apoA-I) for the cholesterol efflux assay.

Results

PTX3 overexpression not only promoted oxLDL uptake but also significantly reduced cholesterol efflux to apoA-I; it also significantly decreased the expression of peroxisome proliferator-activated receptor-γ (PPARγ), liver X receptor alpha (LXRα) and ATP-binding membrane cassette transporter A-1 (ABCA1), which was increased with PTX3 silencing. Furthermore, PTX3 significantly increased p-ERK1/2 levels in THP-1-derived foam cells, and inhibition of ERK1/2 by PD98059 significantly reduced the oxLDL uptake and promoted the cholesterol efflux induced by PTX3 overexpression.

Conclusion

Here, we demonstrate that PTX3 affects lipid accumulation in human macrophages, increasing oxLDL uptake and inhibiting cholesterol efflux. That is the underlying possible mechanisms of PTX3 contribution to the progression of atherosclerosis.     

The use of hollow mesoporous silica nanospheres to encapsulate bortezomib and improve efficacy for non-small cell lung cancer therapy

Bortezomib (BTZ) is the first clinically approved proteasome inhibitor for treating multiple human malignancies. However, the poor water-solubility and low stability of BTZ and the emergence of tumor resistance have severely restrained its therapeutic efficacy. Herein, we report the application of hollow mesoporous silica nanospheres (HMSNs) in encapsulating BTZ for drug delivery. In in vitro cell viability assay on human NSCLC H1299 cells, the half-maximum inhibiting concentration (IC₅₀) of HMSNs–BTZ was 42% of that for free BTZ in 48 h treatments. In vivo tumor-suppression assay further indicated that HMSNs–BTZ (0.3 mg/kg) showed approximately 1.5 folds stronger anti-tumor activity than free BTZ. Furthermore, we report that more potent induction of cell cycle arrest and apoptotic cell death, along with promoted activation of Caspase 3 and autophagy might mechanistically underlie the improved anti-tumor efficacy of HMSNs–BTZ. Finally, the tumor-suppressing effect of HMSNs–BTZ was enhanced in the presence of wild-type p53 signaling, suggesting a potential enhancement in clinical efficacy with combined p53 gene therapy and BTZ-based chemotherapy. Therefore, the HMSNs-based nanoparticles are emerging as a promising platform to deliver therapeutic agents for beneficial clinical outcomes through lowering doses and frequency of drug administration and reducing potential side effects.     

磷脂酰肌醇3激酶／蛋白激酶B通路在缺氧血管内皮细胞凋亡中的作用

目的：探讨磷脂酰肌醇3激酶／蛋白激酶B（PI3 K／Akt）通路在缺氧血管内皮细胞凋亡中的作用。方法（1）常规培养人血管内皮细胞株EA．hy926细胞,取部分人血管内皮细胞株EA．hy926按照随机数字表法分为两组：正常对照组：置于气体成分体积分数5％二氧化碳培养箱中常规培养;缺氧组：置于气体成分体积分数1％氧气、5％二氧化碳和94％氮气的三气培养箱中进行缺氧培养。采用蛋白质印迹法检测正常对照组内皮细胞和缺氧处理3、6、24 h的内皮细胞中Akt活化状态（以pAkt／Akt值表示）,流式细胞仪检测细胞凋亡率。（2）另取部分人血管内皮细胞株EA．hy926按照随机数字表法分为4组：正常对照组,缺氧组：培养方法同前,正常对照＋阻断剂组：用含50μmol／L的LY294002（PI3 K／Akt阻断剂）的培养液常规培养内皮细胞;缺氧＋阻断剂组：用含50μmol／L 的LY294002的培养液缺氧处理内皮细胞。均于培养3 h后收集内皮细胞,采用流式细胞仪检测细胞凋亡率。对Akt活化状态与细胞凋亡率行单因素方差分析和LSD-t检验。结果（1）正常对照组细胞和缺氧处理3、6、24 h的内皮细胞pAkt／Akt值分别为0．67、0．79、0．34和0．35;正常内皮细胞和缺氧处理3、6、24 h 的内皮细胞凋亡率分别为（3．11±0．21）％、（4．57±0．85）％、（6．93±0．58）％、（9．96±2．62）％,组间比较差异有统计学意义（F＝8．96,P＝0．030）。与正常对照组细胞比较,缺氧处理3、6 h的内皮细胞凋亡率升高,差异无统计学意义（t＝1．03、2．70,P＝0．360、0．054）;缺氧处理24 h的内皮细胞凋亡率显著升高,差异有统计学意义（t＝4．99,P＝0．008）。（2）正常对照组、正常对照＋阻断剂组、缺氧组、缺氧＋阻断剂组培养3 h后细胞凋亡率为（2．39±0．50）％、（5．77±1．21）％、（3．76±1．05）％