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1.
T-wave alternans, a specific form of cardiac alternans, has been associated with the increased susceptibility to cardiac arrhythmias and sudden cardiac death (SCD). Plenty of evidence has related cardiac alternans at the tissue level to the instability of voltage kinetics or Ca2+ handling dynamics at the cellular level. However, to date, none of the existing experiments could identify the exact cellular mechanism of cardiac alternans due to the bi-directional coupling between voltage kinetics and Ca2+ handling dynamics. Either of these systems could be the origin of alternans and the other follows as a secondary change, therefore making the cellular mechanism of alternans a difficult chicken or egg problem. In this context, theoretical analysis combined with experimental techniques provides a possibility to explore this problem. In this review, we will summarize the experimental and theoretical advances in understanding the cellular mechanism of alternans. We focus on the roles of action potential duration (APD) restitution and Ca2+ handling dynamics in the genesis of alternans and show how the theoretical analysis combined with experimental techniques has provided us a new insight into the cellular mechanism of alternans. We also discuss the possible reasons of increased propensity for alternans in heart failure (HF) and the new possible therapeutic targets. Finally, according to the level of electrophysiological recording techniques and theoretical strategies, we list some critical experimental or theoretical challenges which may help to determine the origin of alternans and to find more effective therapeutic targets in the future.  相似文献   

2.
INTRODUCTION Left ventricular hypertrophy has been thought to be the principal predicators of predisposing risk factor of cardiac morbidity and mortality (Devereux, 1995; Levy et al., 1990). The pathogenesis that mediates cardiac hypertrophy is poorly understood. Cardiachypertrophy can be induced by hemodynamic over-load, ischemic disease, neurohumoral factors and intrinsic defects in cardiac structural protein genes (Sadoshima and Izumo, 1997; Vikstrom and Lein-wand, 1996). Another in…  相似文献   

3.
ObjectiveCardiac hypertrophy and fibrosis are major pathological manifestations observed in left ventricular remodeling induced by angiotensin II (AngII). Low-intensity pulsed ultrasound (LIPUS) has been reported to ameliorate cardiac dysfunction and myocardial fibrosis in myocardial infarction (MI) through mechano-transduction and its downstream pathways. In this study, we aimed to investigate whether LIPUS could exert a protective effect by ameliorating AngII-induced cardiac hypertrophy and fibrosis and if so, to further elucidate the underlying molecular mechanisms.MethodsWe used AngII to mimic animal and cell culture models of cardiac hypertrophy and fibrosis. LIPUS irradiation was applied in vivo for 20 min every 2 d from one week before mini-pump implantation to four weeks after mini-pump implantation, and in vitro for 20 min on each of two occasions 6 h apart. Cardiac hypertrophy and fibrosis levels were then evaluated by echocardiographic, histopathological, and molecular biological methods.ResultsOur results showed that LIPUS could ameliorate left ventricular remodeling in vivo and cardiac fibrosis in vitro by reducing AngII-induced release of inflammatory cytokines, but the protective effects on cardiac hypertrophy were limited in vitro. Given that LIPUS increased the expression of caveolin-1 in response to mechanical stimulation, we inhibited caveolin-1 activity with pyrazolopyrimidine 2 (pp2) in vivo and in vitro. LIPUS-induced downregulation of inflammation was reversed and the anti-fibrotic effects of LIPUS were absent.ConclusionsThese results indicated that LIPUS could ameliorate AngII-induced cardiac fibrosis by alleviating inflammation via a caveolin-1-dependent pathway, providing new insights for the development of novel therapeutic apparatus in clinical practice.  相似文献   

4.
SIRT1（sirtuin 1）通过对肿瘤抑制蛋白和DNA损伤修复蛋白去乙酰化而使之失活。因此,SIRT1早期被认为是肿瘤促进因子。近来研究又表明SIRT1在某些肿瘤中表达降低且SIRT1缺乏导致遗传不稳定和肿瘤发生。超表达SIRT1可降低癌变风险。SIRT1的这种双重作用可能与其组织中SIRT1上游和下游因子的时空分布不同有关。  相似文献   

5.

Public health perspectives on violence-related injuries have become increasingly important over the past two decades, yet they are rarely mentioned in criminal justice educational texts or articles. Here we provide a brief overview of the public health approach to the prevention of violence and related injuries and compare it to an approach to crime prevention commonly associated with the criminal justice approach: deterrence. The prevention of sexual assault on college and university campuses is used as an illustration of the two approaches. Finally, given the similarities between the manner in which these two multi-disciplinary fields approach violence prevention, we explore how and why criminal justice educators might want to teach a bridge between public health and criminal justice.  相似文献   

6.
Background： Edaravone had been validated to effectively protect against ischemic injuries. In this study, we investigated the protective effect of edaravone by observing the effects on anti-apoptosis, regulation of Bcl-2/Bax protein expression and recovering from damage to mitochondria after OGD （oxygen-glucose deprivation）-reperfusion. Methods： Viability of PC 12 cells which were injured at different time of OGD injury, was quantified by measuring MTT （2-（4,5-dimethylthia-zol-2-yl）-2,5-diphenyltetrazolium bromide） staining. In addition, PC 12 cells＇ viability was also quantified after their preincubation in different concentration of edaravone for 30 min followed by （OGD）. Furthermore, apoptotic population of PC 12 cells that reinsulted from OGD-reperfusion with or without preincubation with edaravone was determined by flow cytometer analysis, electron microscope and Hoechst/Pl staining. Finally, change of Bcl-2/Bax protein expression was detected by Western blot. Results： （1） The viability of PC12 cells decreased with time （1-12 h） after OGD. We regarded the model of OGD 2 h, then replacing DMEM （Dulbecco＇s Modified Eagle＇s Medium） for another 24 h as an OGD-reperfusion in this research. Furthermore, most PC 12 cells were in the state of apoptosis after OGD-reperfusion. （2） The viability of PC 12 cells preincubated with edaravone at high concentrations （1, 0.1, 0.01 μmol/L） increased significantly with edaravone protecting PC 12 cells from apoptosis after OGD-reperfusion injury. （3） Furthermore, edaravone attenuates the damage of OGD-reperfusion on mitochondria and regulated Bcl-2/Bax protein imbalance expression after OGD-reperfusion. Conclusion： Neuroprotective effects of edaravone on ischemic or other brain injuries may be partly mediated through inhibition of Bcl-2/Bax apoptotic pathways by recovering from the damage of mitochondria.  相似文献   

7.
The expression of chromosomal genes is regulated by posttranslational modification of both histone and nonhistone chromatin proteins and ATP-dependent remodeling of chromatin. Dysfunction of the modification and remodeling machineries can lead to several diseases, which include cancer, cardiac hypertrophy, and asthma. Many genetic diseases can also lead to malfunction of the machinery. The enzymes responsible for chromatin organization are the new targets for therapeutics. Inhibitors and activators of histone acetyltransferases and inhibitors of histone deacetylases may serve as new generation drugs.  相似文献   

8.
大学生运动损伤问题研究   总被引：1，自引：0，他引：1  
采用文献资料法、问卷调查法、实地调查法等研究方法,对云南农业大学421名学生在大学一、二年级期间运动损伤状况进行统计分析,结果显示:大学生运动损伤发生率是76.0%,体育生损伤率最高;致伤项目篮球居首位;损伤部位多见于膝关节、踝关节、手关节等;课外活动是损伤的主要场合;损伤常见原因依次是准备活动不合理、技术动作不正确、场地器材情况等;损伤类型以扭伤、擦伤、拉伤、挫伤为主;经过中药、按摩、理疗等治疗,可以得到不同程度的恢复。针对这些特点,提出预防措施,以期为高校的体育教学工作提供服务。  相似文献   

9.
体操教学中运动损伤是经常发生的现象 ,有效地预防运动损伤是体操教学顺利进行的基本保障 .本文探讨了体操教学运动损伤的特殊规律 ,为其科学的预防提供了有益的参考  相似文献   

10.
张宇 《宜春学院学报》2012,34(4):112-115
排球是一项普及程度极广的体育运动,对参加者的跳跃能力有很强的要求。跳跃落地动作对下肢的冲击是造成排球运动中膝、踝关节损伤与应力性骨折的重要原因。本文对损伤产生的机制进行了相应分析,并提出了相应运动干预的措施以有效避免损伤的发生。  相似文献   

11.

Objective

To investigate the beneficial effect of bicyclol on rat hearts subjected to ischemia-reperfusion (IR) injuries and its possible mechanism.

Methods

Male Sprague-Dawley rats were intragastrically administered with bicyclol (25, 50 or 100 mg/(kg·d)) for 3 d. Myocardial IR was produced by occlusion of the coronary artery for 1 h and reperfusion for 3 h. Left ventricular hemodynamics was continuously monitored. At the end of reperfusion, myocardial infarct was measured by 2,3,5-triphenyltetrazolium chloride (TTC) staining, and serum lactate dehydrogenase (LDH) level and myocardial superoxide dismutase (SOD) activity were determined by spectrophotometry. Isolated ventricular myocytes from adult rats were exposed to 60 min anoxia and 30 min reoxygenation to simulate IR injuries. After reperfusion, cell viability was determined with trypan blue; reactive oxygen species (ROS) and mitochondrial membrane potential of the cardiomyocytes were measured with the fluorescent probe. The mitochondrial permeability transition pore (mPTP) opening induced by Ca2+ (200 μmol/L) was measured with the absorbance at 520 nm in the isolated myocardial mitochondria.

Results

Low dose of bicyclol (25 mg/(kg·d)) had no significant improving effect on all cardiac parameters, whereas pretreatment with high bicyclol markedly reduced the myocardial infarct and improved the left ventricular contractility in the myocardium exposed to IR (P<0.05). Medium dose of bicyclol (50 mg/(kg·d)) markedly improved the myocardial contractility, left ventricular myocyte viability, and SOD activity, as well decreased infarct size, serum LDH level, ROS production, and mitochondrial membrane potential in rat myocardium exposed to IR. The reduction of ventricular myocyte viability in IR group was inhibited by pretreatment with 50 and 100 mg/(kg·d) bicyclol (P<0.05 vs. IR), but not by 25 mg/(kg·d) bicyclol. The opening of mPTP evoked by Ca2+ was significantly inhibited by medium bicyclol.

Conclusions

Bicyclol exerts cardioprotection against IR injury, at least, via reducing oxidative stress and its subsequent mPTP opening.  相似文献   

12.
随着篮球运动的发展，参加篮球运动的人越来越多，在篮球运动中难免会发生一些损伤。本文通过对篮球运动中常出现的运动损伤机理的初步分析。提出一些相应的治疗方法和预防措施。以避免或减少篮球运动中损伤的发生。  相似文献   

13.
运动训练能促使骨骼肌在形态与结构上发生适应性的改变,如肌纤维类型转化、肌纤维选择性肥大等。钙调神经磷酸酶（CaN）是钙离子的下游因子,对细胞内因钙离子升高引起的心肌肥大起着重要作用。CaN的活性与肌纤维类型的表达和肌纤维选择性肥大有着非常紧密的联系。对CaN在运动过程中对心肌和骨骼肌的作用及调节进行综述。  相似文献   

14.
Disulfide-bond A oxidoreductase-like protein (DsbA-L) is a molecular chaperone involved in the multimerization of adiponectin. Recent studies have found that DsbA-L is related to metabolic diseases including gestational diabetes mellitus (GDM), and can be regulated by peroxisome proliferator-activated receptor γ (PPARγ) agonists; the specific mechanism, however, is uncertain. Furthermore, the relationship between DsbA-L and the novel adipokine chemerin is also unclear. This article aims to investigate the role of DsbA-L in the improvement of insulin resistance by PPARγ agonists in trophoblast cells cultured by the high-glucose simulation of GDM placenta. Immunohistochemistry and western blot were used to detect differences between GDM patients and normal pregnant women in DsbA-L expression in the adipose tissue. The western blot technique was performed to verify the relationship between PPARγ agonists and DsbA-L, and to explore changes in key molecules of the insulin signaling pathway, as well as the effect of chemerin on DsbA-L. Results showed that DsbA-L was significantly downregulated in the adipose tissue of GDM patients. Both PPARγ agonists and chemerin could upregulate the level of DsbA-L. Silencing DsbA-L affected the function of rosiglitazone to promote the phosphatidylinositol 3-kinase (PI3K)-protein kinase B (PKB)/AKT pathway. Therefore, it is plausible to speculate that DsbA-L is essential in the environment of PPARγ agonists for raising insulin sensitivity. Overall, we further clarified the mechanism by which PPARγ agonists improve insulin resistance.  相似文献   

15.

Objective

To evaluate the clinical efficacy of levosimendan versus dobutamine in critically ill patients requiring inotropic support.

Methods

Clinical trials were searched in PubMed, EMBASE, and the Cochrane Central Registry of Clinical Trials, as well as Web of Science. Studies were included if they compared levosimendan with dobutamine in critically ill patients requiring inotropic support, and provided at least one outcome of interest. Outcomes of interest included mortality, incidence of hypotension, supraventricular arrhythmias, and ventricular arrhythmias.

Results

Data from a total of 3 052 patients from 22 randomized controlled trials (RCTs) were included in the analysis. Overall analysis showed that the use of levosimendan was associated with a significant reduction in mortality (269 of 1 373 [19.6%] in the levosimendan group, versus 328 of 1 278 [25.7%] in the dobutamine group, risk ratio (RR)=0.81, 95% confidence interval (CI) 0.70-0.92, P for effect=0.002). Subgroup analysis indicated that the benefit from levosimendan could be found in the subpopulations of cardiac surgery, ischemic heart failure, and concomitant β-blocker therapy in comparison with dobutamine. There was no significant difference in the incidence of hypotension, supraventricular arrhythmias, or ventricular arrhythmias between the two drugs.

Conclusions

In contrast with dobutamine, levosimendan is associated with a significant improvement in mortality in critically ill patients requiring inotropic support. Patients having cardiac surgery, with ischemic heart failure, and receiving concomitant β-blocker therapy may benefit from levosimendan. More RCTs are required to address the questions about no positive outcomes in the subpopulation in a cardiology setting, and to confirm the advantages in long-term prognosis.  相似文献   

16.
Children growing up in poverty are at risk for various health problems. For low-income, Mexican-American children, these risks include obesity, diabetes, and accidental injuries, 3 conditions that can largely be prevented by healthy life-styles. Despite the potential for prevention through education leading to health-promoting behaviors, very little is known about the development of health knowledge in this population. The present study examined low-income, Mexican-American children's understanding of the relation between health behavior and health status in 3 areas: nutrition, hygiene, and safety. 79 children (41 boys, 38 girls) ages 4 to 8 years participated. Children's knowledge was assessed in a structured play situation conducted in a laboratory setting. Results revealed that children knew the least about the relation between food consumption and their health, and knew the most about beneficial and harmful practices in the areas of safety and hygiene. Age and gender differences were also significant, with girls and older children more likely to provide elaborate and complex rationales for their responses. Implications of the findings for understanding the role of cognitive development and experience in the development of health knowledge are considered.  相似文献   

17.
采用文献资料法、问卷调查法、数理统计法对淮南师范学院体育学院篮球专项班60名篮球运动员一年内的损伤次数、导致损伤的因素、发生损伤的部位、运动损伤的预防措施等进行调查分析。结论:①篮球运动员的运动损伤发生率高。前锋、中锋比后卫损伤发生率高,其中前锋最容易发生损伤。②篮球运动员损伤发生率女性高于男性,男性易损伤部位集中在腰背部、踝部、膝部、肩部,而女性易损伤的部位集中在踝部、肩部、膝部、腰背部。③导致篮球运动运动损伤的主要因素是旧伤病未痊愈、准备活动不充分、身体过度疲劳、注意力不集中、带伤训练比赛、技术应用不熟练等。④比赛后疲劳的消除、身体素质的全面训练、专项耐力训练、科学组织体育教学等应成为今后篮球教学和训练中预防措施的主要方面。  相似文献   

18.
随着全民体育健身计划的全面推行,体育教育改革的深入发展．篮球运动作为一项重要而且普及的运动项目受到越来越多人的喜爱,同时运动损伤的发生又是不可避免的．因此,如何科学、合理、系统地进行篮球教学、训练、运动,最大限度地避免或减少运动损伤的发生,是我们体育教师、教练员以及广大篮球爱好者应该引起重视、预防和解决的一个重要课题．  相似文献   

19.
In order to clarify the equilibrium components in the hydrolysis solution of boron trifluoride(BF_3-H_2O),the BF_3-H_2O was prepared by mixing BF_3-CH_3OH with large amount of water,in which the stoichiometric concentration of BF_3 is less than 0.1 mol/L.Two ionic equilibrium models were proposed to simulate the hydrolysis equilibrium of BF_3 and tested by special acid-base titration technique.The most accurate ion equilibrium constants were determined.The model,which was assumed to have no HF,was proved to be more representative for the real system and used to simulate the hydrolysis equilibrium of BF_3.The simulation suggested that H~+,BF_4~-,BF_3OH~- and H_3BO_3 were the main species in the dilute hydrolysis solution,while BF_2(OH)_2~- and F~- were insignificant species whose concentrations were both in the order of 10~(-4) mol/L magnitude,and BF(OH)_3~- could be omitted because its concentration almost equaled zero.Meanwhile,the equilibrium constant of the overall ionic reaction at 25℃ was obtained as 161.6.  相似文献   

20.
正确认识贯彻落实《条例》,加强工伤保险基金的管理,切实加强工伤预防,是企业实现经济持续、快速发展的最有力保障,同时也可以为企业实现生产经营秩序稳定,赢造良好的安全生产氛围,构建和谐矿区打好工作基础。  相似文献   

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