长光程薄层光谱电化学法研究溶液反应及电极表面行为

本论文用光谱电化学法进行了有机分子的电极过程动力学和电极/溶液界面状态两个方面的研究。采用长光程光透薄层光谱电化学池，不仅测定了有关的热力学参数，研究和阐明了电极反应历程和机理，进一步提出和发展了用薄层光谱电化学研究快速反应的动力学方法；而且开展了电非活性分子在电极表面上吸附、定向、及其定向转化的热力学研究，另外发现和研究了电致二色性效应。首次研究了阳离子表面活性剂—溴化十六烷基吡啶（CPB）在玻碳电极表面上吸附行为，由光谱电化学实验结果和分子结构提出CPB在玻碳表面上吸附有四种较稳定的定向，经历了三次较大的吸附定向的转化过程，给出了分子在电极表面吸附的分子水平的微观信息。并表明微分吸附等温曲线法是研究有机物吸附定向及其转化的更为敏锐的方法。吸附等温曲线的理论处理，证明了CPB的每一定向吸附过程服从两个Frumkin等温吸附方程前者主要由化学亲合力控制，后者由晶格吸引力控制。揭示了长链烷烃的吸附特性，解释了CPB及某些中性有机化合物在高覆盖度下偏离Frumkin等温吸附方程的现象。提出了临界覆盖度概念，从而首次进行了吸附定向及其转化的热力学处理。获得各种吸附定向的吸附自由能及吸附定向转化的自由能变化和热力学平衡常数。从热力学方面预测了各种吸附定向的稳定性，吸附定向转化的推动力和可能性。从而深化了吸附的理论研究，使得较复杂有机化合物的复杂吸附过程的理论处理成为可能。CPB在玻碳电极表面上吸附的交流阻抗研究表明，在高频区出现了与电解池结构有关的阻抗，具有半园旋转特性。通过假设存在着频率相关的电容和电阻与池结构电容、溶液电阻构成等效电路。理论处理的予计结果完全与我们的实验吻合，而且对于文献中交流阻抗图高频端出现的变形现象提出了定性地解释。通过假定CPB在玻碳电极表面上形成单分子吸附膜的模型，推导出的结果（与吸附有关的阻抗图及warburg阻抗图）与实验数据完全一致。由warburg阻抗中求出的CPB扩散系数为7.07 * 10~(-8)cm~2/s，流体动力学半径为3.52A°，证明了CPB分子在LOPTLC中，由于流体场的作用形成有序排列，其扩散过程为CPB分子的群体行为，为CPB电致二色性研究提供依据。微分电容曲线的研究证明，在较低覆盖度下，CPB上的BF与电极表面接触，在电场作用下，CPB分子发生定向转化，由低密度定向向高密度定向转化，出现了多个峰电容。在较高覆盖度下，CPB中的BF离子离开电极表面，吸附行为与中性有机物的吸附行为相似，仅出现两个峰电容，没有BF的吸附—解吸峰。从而为由吸附等温曲线中推测的吸附定向提供依据。首次发现并研究了CPB的电致二色性效应，结果表明，CPB的电致二色性疚主要是由于偶极分子在电场作用下进行重新定向引起的。进一步研究了CPB浓度及有效电场强度的影响，电致二色性效应在低电位下与CPB的浓度成反比，较高电位下，与ECOSO呈正比。在高电位下，由于电化学反应引起有效电场强度降低，使电致二色性效应下降。这一研究为液晶体系中电致二色性的研究提供了有力的工具，扩展了研究的因素，也为光谱电化学方法研究液晶体系的电化学提供了基础性研究体系。茜素红S（ARS）在玻碳电极上电极行为的研究证明了，在1.0—0.0伏电位范围内，ARS的氧化过程不是一步不可逆过程，而是2个电子的氧化过程与一个后行化学反应构成了ECE循环机理。氧化和还原过程中还包括了一个质子的两电子氧化还原步骤和一个质子传递步骤构成的EC和CE机理。后行化学反应为ARS氧化产物与ARS形成氢键的反应，化学反应的产物经历一个不可逆氧化还原过程，还原产物为ARS。光谱电化学方法求得表观式电位为，E' = 0.34 5伏（VS·SCE），αn = 0.625。首次提出了单电位跃计时吸收法（用LOPTLC）测定快速后行化学反应速率的方法，测得ARS的后行化学反应平衡常数为7.94 * 10~5 l/mol，反应自由能为，8.05 kcal/mol (25 ℃)，与其它方法估计的结果吻合。测出的动力学速率常数为426.6 l/mol·s。扩展了LOPTLC法在快速反应动力学方面的应用。以上研究结果表明，本论文发展了光透式薄层光谱电化学的研究和应用范围，克服了以往多用于研究溶液反应的局限性，使此方法在研究电极/溶液界面现象方面能够与反射式光谱电化学法相比，而且具有方法简单，反映直观、测定灵敏、定量的特点，将有力地推动今后这方面的研究发展。

古油松年轮记录的沈阳地区300年来的气候变化

本研究通过对沈阳清•昭陵、清•福陵和千山风景区树木年轮气候学考察和取样，共采集了103株古油松样本的树芯和轮盘。依据树木年轮气候学研究的规范做法建立了3地区的STD, RES, ARS三种类型的树轮宽度年表9个。并分析了不同采样点树木年轮所反映的气候信息，在此基础上重建了该区域近300年来的气候变化，开展了区域以及全球气候变化对比研究，以探讨沈阳地区近300年来气候变化的特点、规律和机制： （1）古油松年表与冬季和初春低温的关系较明显，1月的低温最显著，3种年表与冬季、春季和秋季的降水量的相关性均较显著。水汽压、相对湿度在入冬前、生长后期和易发生春旱的5-6月份对年轮宽度的影响表现突出。蒸发是上年全年、当年全年和当年绝大部分月份对油松生长起负效应的因素，其中5月最明显，但1、2月的蒸发量与油松当年的年轮宽度表现出正相关。油松年表的窄轮和窄化突变佐证了1650年以来的35次主要的旱灾年历史记录和59次干旱记录。 （2）本研究成功地检验了沈阳地区古油松年轮宽度年表对太阳活动，地磁活动，太平洋十年震荡和全球气温变化的响应。年轮宽度与这些影响因子均存在共同的周期变化和显著的线性关系。其中，年轮宽度对过去太阳活动和地磁的活动呈明显负相关关系，而且是多种抑、促效应的复合。所有结果表明沈阳城市古油松适于监测极度的诸如El Niño (La Niña)事件的全球环境变化和区域环境异常。 （3）本研究重建了沈阳地区1710-2004年12-1月的极端最低温，并指出其主要低温波动期，高温波动期；重建了沈阳地区1780-2004年1-6月的降水量，并统计了降水量反映的偏湿年份,，偏干年份；同时，分别重建了沈阳地区1780-2004年的年均水汽压、年蒸发量和年均相对湿度，并指出各重建结果所表征的旱涝年份。

基于ECRIS的等电荷态序列离子与氦、氖、氩碰撞反应中的多电子过程研究

本工作设计并建立了一个离子-原子碰撞实验终端。该终端具有一定的通用性，可用于我所EcRIS、ECRIS一300kV高压平台和兰州大学Zxl．7MV串列加速器。终端的设计特别考虑了气体靶实验中系统的动态真空和对高品质弱束流流强的控制。2004年7月-10月，利用我所ECRIS提供的束流，在该终端上进行了首轮实验。本工作指出，除了入射离子的电荷态和速度外，其空能级结构是碰撞反应的另一个主导因素，并在此基础上提出了等电荷态序列离子的概念。为了确定离子空能级结构对碰撞反应的影响，本工作系统研究了等速度的q＝6序列离子（C6＋、N6＋、。6＋、F6＋、Ne6＋、Ar6＋、co6＋）、q＝7序列离子（07＋、F7＋、Ne7＋、57＋、Ar7＋）、q＝8序列离子（FS＋、Nes＋、Ars＋、cos＋）、q：9序列离子（Fg＋、Neg＋、519＋、59＋、Arg＋、cag＋）和叮：11序列离子（Si1、Aill＋、Call＋）与氦、氖、氢的碰撞反应。实验证实，对于等速度、等电荷态序列离子，碰撞反应与离子种类强烈相关。利用同位素纯的13coZ作为EcRIs的工作气体，获得了纯净的全裸离子13C6＋束流，研究了13C6＋离子与氦、氖、氢碰撞反应与碰撞速度的关系。实验发现，在C6十一He的碰撞反应中，纯双电子俘获（DC）与双电子转移（DE）截面比JDcDIZ随碰撞速度的增加而明显下降，这暗示准分子俄歇机制在本能区C6＋一He碰撞反应中的贡献不可忽略。用MCBM描述离子-原子相互作用阶段，用电子蒸发模型统一处理碰撞后多电了激发态散射离子和反冲离子的衰变，作者编写了计算程序COBEEM。经典过垒模型（如ECBM和MCBM）仅用电荷态q一个参数描述入射离子，本工作实验证实了这种描述是不完备的。COBEEM程序对此问题进行了初步修正。该程序还包含了ECBM和Selberg等人提出了经验公式的计算。

高电荷态离子引起的富勒烯离子的碎裂研究

在里昂第一大学原子物理平台上，采用静电离子阱技术，我们在三个激发能区内研究了高电荷态离子与富勒烯作用后C603”离子的稳定性及其碎裂方式。在56 kev的Ars＋离子与富勒烯碰撞中，当碰撞参数很大时，稳定的C研离子被一个静电离子阱俘获，储存一段时间后存活的离子被探测器测量，实验结果显示C_16oll（l．＝2-5）离子的损失主要是由于与剩余气体发生电荷交换，其相对于碎裂衰变过程的寿命大于400毫秒。在‘擦边碰撞，过程条件下，研究了处于低激发态的C60r+离子在20微秒内蒸发CZ分子的过程。基于考虑了热辐射的统计模型，给出了碰撞产生的C60r+离子的激发能的分布。随着碰撞参数的减小，当入射离子穿过C6。分子时，由于电子阻止使C6厂离子处于高激发态。通过测量发射电子数目，实验上确定了C60r＋离子的初始电荷态，本工作分析了高激发态的C60r＋离子碎裂前的电荷态与入射离子速度之间的关系，发现C60r”离子的碎裂方式只与它的初始电荷态有关，而与入射离子速度无关；同时，发射电子的个数可以用来表征C60什离子的激发能的大小

Differential proteomic analysis of neonatal cardiomyocytes in response to beta-adrenergic receptor stimulation

beta-Adrenoceptors(beta-ARs) play a critical role in regulating cardiac functions under both physiological and pathological conditions. To further explore the mechanisms through which beta-ARs perform its actions, proteomic approaches were adopted to study the global protein patterns in cultured neonatal rat cardiomyocytes exposed to isoproterenol (ISO). A modified method, "Mirror Images in One Gel", was used to improve the reproducibility and resolution power of two-dimensional electrophoresis. A 2-DE map with a good reproducibility was obtained in which 1281 70 spots were detected and about 1191 +/- 54 spots were matched, with an average matching rate of 92.9%. Nine proteins with significant changes were identified by using peptide mass fingerprinting(PMF) data obtained via MALDI-MS.

DETERMINATION OF PARAMETERS OF FAST CHEMICAL REACTION OF ALIZARIN RED S BY SPECTROELECTROCHEMICAL METHOD WITH LOPTLC

The rate constant of very fast chemical reaction generally can be measured by electrochemical methods, but can not by the thin layer electrochemical methods because of the influence of diffusion effect. Long optical path length thin layer cell (LOPTLC) with large ratio of electrode area to solution volume can be used to monitor the fist chemical reaction in situ with high sensitivity and accuracy. It enable the adsorption spectra to be measured without the influence of diffusion effect. In the present paper, a fast chemical reaction of Alizarin Red S (ARS) with its oxidative state has been studied. The reaction equilibrium constant (K) under different potentials can be determined by single step potential-absorption spectra in LOPTLC. An equilibrium constant of 7.94 x 10(5) l.mol(-1) for the chemical reaction has been obtained from the plot of lgK vs. (E - E-1(0)'). Rate constant (k) under different potentials can be measured by single step potential-chronoabsorptiometry. A rate constant of 426.6 l.mol(-1).s(-1) for the chemical reaction has been obtained from the plot of lgK vs. (E - E-1(0)') with (E - E-1(0)') = 0.

Caracterização de raças de Pyrenophora tritici-repentis, agente etiológico da mancha amarela do trigo, no sul do Brasil.

2008

Badania archeologiczne a obrazowanie wizualne przeszłości

One can say that our times are dominated by visual communication. Usually all day long we have been faced by various pictures, visual forms and symbols. According to the subject of the book 'Archaeology-Culture-Ideologies' I found it interesting to pay attention to the problem of visual representation, or better say visual symbols in nowadays communication and culture, their meaning and importance. From this point of view I would like to show the role of archaeologists who discover, interpret or even create some of them. The subject is not new of course, but the most often it is taken into consideration by the scholars who practice in social anthropology or philosophy and quite rarely it appear in studies of archaeologies, especially in Polish tradition. In my opinion the subject concerning visual symbols communication and archaeology arise several important questions that are also valid for the theme of book 'Archaeology-Culture-Ideologies'. The first is socio-cultural role of our discipline, next the danger of political and propaganda misuse of the results of archaeological research and then also commercialisation of the archaeological activities. The problem of visualisation and visual-communication can be the matter of various studies. In my paper from the beginning I would like to present the general view concerning visual symbols and figural motifs and the main ideas and approaches to study them from different humanistic perspectives. Then in my presentation I am going to discuss the question why in our culture the visual symbols and representations became so popular – compare to other ways of human expression, for example verbal symbol communication. I would like to see the problem in historical perspective as well. There are a lot of evidences, which support the statement about the power of visual symbols in history. In ancient times for example Horace in 'Ars Poetica' suggested that human mind usually is much more impressed by eyes than by ears. In my opinion that is quite often in human culture that visual impression is before mental one. Visual representations and symbols are very powerful, they can show and communicate various phenomena, they act immediately and quite often in easily way they can associate. So for archaeological research it could be very important to make some studies concerning the ancient symbols and general iconography and also it would be grateful to make some attempts for the study what kind of potential meaning could have visual symbols. In my paper I can only make some general statement about it. But the most important for the topic is reflection on prehistoric and ancient visual symbols and representation and their presence in contemporary culture. So after some general statements concerning the visual symbols examined from various perspectives finally I would like to point out with support of some examples how ancient and prehistoric visual symbols and images are still used and captured by contemporary culture and what is or should be the role of archaeologists activity concerning this matter.

FLT3-driven redox signalling in acute myeloid leukaemia

Acute myeloid leukaemia refers to cancer of the blood and bone marrow characterised by the rapid expansion of immature blasts of the myeloid lineage. The aberrant proliferation of these blasts interferes with normal haematopoiesis, resulting in symptoms such as anaemia, poor coagulation and infections. The molecular mechanisms underpinning acute myeloid leukaemia are multi-faceted and complex, with a range of diverse genetic and cytogenetic abnormalities giving rise to the acute myeloid leukaemia phenotype. Amongst the most common causative factors are mutations of the FLT3 gene, which codes for a growth factor receptor tyrosine kinase required by developing haematopoietic cells. Disruptions to this gene can result in constitutively active FLT3, driving the de-regulated proliferation of undifferentiated precursor blasts. FLT3-targeted drugs provide the opportunity to inhibit this oncogenic receptor, but over time can give rise to resistance within the blast population. The identification of targetable components of the FLT3 signalling pathway may allow for combination therapies to be used to impede the emergence of resistance. However, the intracellular signal transduction pathway of FLT3 is relatively obscure. The objective of this study is to further elucidate this pathway, with particular focus on the redox signalling element which is thought to be involved. Signalling via reactive oxygen species is becoming increasingly recognised as a crucial aspect of physiological and pathological processes within the cell. The first part of this study examined the effects of NADPH oxidase-derived reactive oxygen species on the tyrosine phosphorylation levels of acute myeloid leukaemia cell lines. Using two-dimensional phosphotyrosine immunoblotting, a range of proteins were identified as undergoing tyrosine phosphorylation in response to NADPH oxidase activity. Ezrin, a cytoskeletal regulatory protein and substrate of Src kinase, was selected for further study. The next part of this study established that NADPH oxidase is subject to regulation by FLT3. Both wild type and oncogenic FLT3 signalling were shown to affect the expression of a key NADPH oxidase subunit, p22phox, and FLT3 was also demonstrated to drive intracellular reactive oxygen species production. The NADPH oxidase target protein, Ezrin, undergoes phosphorylation on two tyrosine residues downstream of FLT3 signalling, an effect which was shown to be p22phox-dependent and which was attributed to the redox regulation of Src. The cytoskeletal associations of Ezrin and its established role in metastasis prompted the investigation of the effects of FLT3 and NADPH oxidase activity on the migration of acute myeloid leukaemia cell lines. It was found that inhibition of either FLT3 or NADPH oxidase negatively impacted on the motility of acute myeloid leukaemia cells. The final part of this study focused on the relationship between FLT3 signalling and phosphatase activity. It was determined, using phosphatase expression profiling and real-time PCR, that several phosphatases are subject to regulation at the levels of transcription and post-translational modification downstream of oncogenic FLT3 activity. In summary, this study demonstrates that FLT3 signal transduction utilises a NADPH oxidase-dependent redox element, which affects Src kinase, and modulates leukaemic cell migration through Ezrin. Furthermore, the expression and activity of several phosphatases is tightly linked to FLT3 signalling. This work reveals novel components of the FLT3 signalling cascade and indicates a range of potential therapeutic targets.

Superoxide dismutase mimics: chemistry, pharmacology, and therapeutic potential.

Oxidative stress has become widely viewed as an underlying condition in a number of diseases, such as ischemia-reperfusion disorders, central nervous system disorders, cardiovascular conditions, cancer, and diabetes. Thus, natural and synthetic antioxidants have been actively sought. Superoxide dismutase is a first line of defense against oxidative stress under physiological and pathological conditions. Therefore, the development of therapeutics aimed at mimicking superoxide dismutase was a natural maneuver. Metalloporphyrins, as well as Mn cyclic polyamines, Mn salen derivatives and nitroxides were all originally developed as SOD mimics. The same thermodynamic and electrostatic properties that make them potent SOD mimics may allow them to reduce other reactive species such as peroxynitrite, peroxynitrite-derived CO(3)(*-), peroxyl radical, and less efficiently H(2)O(2). By doing so SOD mimics can decrease both primary and secondary oxidative events, the latter arising from the inhibition of cellular transcriptional activity. To better judge the therapeutic potential and the advantage of one over the other type of compound, comparative studies of different classes of drugs in the same cellular and/or animal models are needed. We here provide a comprehensive overview of the chemical properties and some in vivo effects observed with various classes of compounds with a special emphasis on porphyrin-based compounds.

Augmentation of cardiac contractility mediated by the human beta(3)-adrenergic receptor overexpressed in the hearts of transgenic mice.

BACKGROUND: Stimulation of beta(1)- and beta(2)-adrenergic receptors (ARs) in the heart results in positive inotropy. In contrast, it has been reported that the beta(3)AR is also expressed in the human heart and that its stimulation leads to negative inotropic effects. METHODS AND RESULTS: To better understand the role of beta(3)ARs in cardiac function, we generated transgenic mice with cardiac-specific overexpression of 330 fmol/mg protein of the human beta(3)AR (TGbeta(3) mice). Hemodynamic characterization was performed by cardiac catheterization in closed-chest anesthetized mice, by pressure-volume-loop analysis, and by echocardiography in conscious mice. After propranolol blockade of endogenous beta(1)- and beta(2)ARs, isoproterenol resulted in an increase in contractility in the TGbeta(3) mice (30%), with no effect in wild-type mice. Similarly, stimulation with the selective human beta(3)AR agonist L-755,507 significantly increased contractility in the TGbeta(3) mice (160%), with no effect in wild-type mice, as determined by hemodynamic measurements and by end-systolic pressure-volume relations. The underlying mechanism of the positive inotropy incurred with L-755,507 in the TGbeta(3) mice was investigated in terms of beta(3)AR-G-protein coupling and adenylyl cyclase activation. Stimulation of cardiac membranes from TGbeta(3) mice with L-755,507 resulted in a pertussis toxin-insensitive 1.33-fold increase in [(35)S]GTPgammaS loading and a 1.6-fold increase in adenylyl cyclase activity. CONCLUSIONS: Cardiac overexpression of human beta(3)ARs results in positive inotropy only on stimulation with a beta(3)AR agonist. Overexpressed beta(3)ARs couple to G(s) and activate adenylyl cyclase on agonist stimulation.

Hybrid transgenic mice reveal in vivo specificity of G protein-coupled receptor kinases in the heart.

G protein-coupled receptor kinases (GRKs) phosphorylate activated G protein-coupled receptors, including alpha(1B)-adrenergic receptors (ARs), resulting in desensitization. In vivo analysis of GRK substrate selectivity has been limited. Therefore, we generated hybrid transgenic mice with myocardium-targeted overexpression of 1 of 3 GRKs expressed in the heart (GRK2 [commonly known as the beta-AR kinase 1], GRK3, or GRK5) with concomitant cardiac expression of a constitutively activated mutant (CAM) or wild-type alpha(1B)AR. Transgenic mice with cardiac CAMalpha(1B)AR overexpression had enhanced myocardial alpha(1)AR signaling and elevated heart-to-body weight ratios with ventricular atrial natriuretic factor expression denoting myocardial hypertrophy. Transgenic mouse hearts overexpressing only GRK2, GRK3, or GRK5 had no hypertrophy. In hybrid transgenic mice, enhanced in vivo signaling through CAMalpha(1B)ARs, as measured by myocardial diacylglycerol content, was attenuated by concomitant overexpression of GRK3 but not GRK2 or GRK5. CAMalpha(1B)AR-induced hypertrophy and ventricular atrial natriuretic factor expression were significantly attenuated with either concurrent GRK3 or GRK5 overexpression. Similar GRK selectivity was seen in hybrid transgenic mice with wild-type alpha(1B)AR overexpression concurrently with a GRK. GRK2 overexpression was without effect on any in vivo CAM or wild-type alpha(1B)AR cardiac phenotype, which is in contrast to previously reported in vitro findings. Furthermore, endogenous myocardial alpha(1)AR mitogen-activated protein kinase signaling in single-GRK transgenic mice also exhibited selectivity, as GRK3 and GRK5 desensitized in vivo alpha(1)AR mitogen-activated protein kinase responses that were unaffected by GRK2 overexpression. Thus, these results demonstrate that GRKs differentially interact with alpha(1B)ARs in vivo such that GRK3 desensitizes all alpha(1B)AR signaling, whereas GRK5 has partial effects and, most interestingly, GRK2 has no effect on in vivo alpha(1B)AR signaling in the heart.

Identification of the endophilins (SH3p4/p8/p13) as novel binding partners for the beta1-adrenergic receptor.

Several G-protein coupled receptors, such as the beta1-adrenergic receptor (beta1-AR), contain polyproline motifs within their intracellular domains. Such motifs in other proteins are known to mediate protein-protein interactions such as with Src homology (SH)3 domains. Accordingly, we used the proline-rich third intracellular loop of the beta1-AR either as a glutathione S-transferase fusion protein in biochemical "pull-down" assays or as bait in the yeast two-hybrid system to search for interacting proteins. Both approaches identified SH3p4/p8/p13 (also referred to as endophilin 1/2/3), a SH3 domain-containing protein family, as binding partners for the beta1-AR. In vitro and in human embryonic kidney (HEK) 293 cells, SH3p4 specifically binds to the third intracellular loop of the beta1-AR but not to that of the beta2-AR. Moreover, this interaction is mediated by the C-terminal SH3 domain of SH3p4. Functionally, overexpression of SH3p4 promotes agonist-induced internalization and modestly decreases the Gs coupling efficacy of beta1-ARs in HEK293 cells while having no effect on beta2-ARs. Thus, our studies demonstrate a role of the SH3p4/p8/p13 protein family in beta1-AR signaling and suggest that interaction between proline-rich motifs and SH3-containing proteins may represent a previously underappreciated aspect of G-protein coupled receptor signaling.

Overexpression of the cardiac beta(2)-adrenergic receptor and expression of a beta-adrenergic receptor kinase-1 (betaARK1) inhibitor both increase myocardial contractility but have differential effects on susceptibility to ischemic injury.

Cardiac beta(2)-adrenergic receptor (beta(2)AR) overexpression is a potential contractile therapy for heart failure. Cardiac contractility was elevated in mice overexpressing beta(2)ARs (TG4s) with no adverse effects under normal conditions. To assess the consequences of beta(2)AR overexpression during ischemia, perfused hearts from TG4 and wild-type mice were subjected to 20-minute ischemia and 40-minute reperfusion. During ischemia, ATP and pH fell lower in TG4 hearts than wild type. Ischemic injury was greater in TG4 hearts, as indicated by lower postischemic recoveries of contractile function, ATP, and phosphocreatine. Because beta(2)ARs, unlike beta(1)ARs, couple to G(i) as well as G(s), we pretreated mice with the G(i) inhibitor pertussis toxin (PTX). PTX treatment increased basal contractility in TG4 hearts and abolished the contractile resistance to isoproterenol. During ischemia, ATP fell lower in TG4+PTX than in TG4 hearts. Recoveries of contractile function and ATP were lower in TG4+PTX than in TG4 hearts. We also studied mice that overexpressed either betaARK1 (TGbetaARK1) or a betaARK1 inhibitor (TGbetaARKct). Recoveries of function, ATP, and phosphocreatine were higher in TGbetaARK1 hearts than in wild-type hearts. Despite basal contractility being elevated in TGbetaARKct hearts to the same level as that of TG4s, ischemic injury was not increased. In summary, beta(2)AR overexpression increased ischemic injury, whereas betaARK1 overexpression was protective. Ischemic injury in the beta(2)AR overexpressors was exacerbated by PTX treatment, implying that it was G(s) not G(i) activity that enhanced injury. Unlike beta(2)AR overexpression, basal contractility was increased by betaARK1 inhibitor expression without increasing ischemic injury, thus implicating a safer potential therapy for heart failure.

Intracoronary adenovirus-mediated delivery and overexpression of the beta(2)-adrenergic receptor in the heart : prospects for molecular ventricular assistance.

BACKGROUND: Genetic modulation of ventricular function may offer a novel therapeutic strategy for patients with congestive heart failure. Myocardial overexpression of beta(2)-adrenergic receptors (beta(2)ARs) has been shown to enhance contractility in transgenic mice and reverse signaling abnormalities found in failing cardiomyocytes in culture. In this study, we sought to determine the feasibility and in vivo consequences of delivering an adenovirus containing the human beta(2)AR cDNA to ventricular myocardium via catheter-mediated subselective intracoronary delivery. METHODS AND RESULTS: Rabbits underwent percutaneous subselective catheterization of either the left or right coronary artery and infusion of adenoviral vectors containing either a marker transgene (Adeno-betaGal) or the beta(2)AR (Adeno-beta(2)AR). Ventricular function was assessed before catheterization and 3 to 6 days after gene delivery. Both left circumflex- and right coronary artery-mediated delivery of Adeno-beta(2)AR resulted in approximately 10-fold overexpression in a chamber-specific manner. Delivery of Adeno-betaGal did not alter in vivo left ventricular (LV) systolic function, whereas overexpression of beta(2)ARs in the LV improved global LV contractility, as measured by dP/dt(max), at baseline and in response to isoproterenol at both 3 and 6 days after gene delivery. CONCLUSIONS: Percutaneous adenovirus-mediated intracoronary delivery of a potentially therapeutic transgene is feasible, and acute global LV function can be enhanced by LV-specific overexpression of the beta(2)AR. Thus, genetic modulation to enhance the function of the heart may represent a novel therapeutic strategy for congestive heart failure and can be viewed as molecular ventricular assistance.