大鼠心肌急性缺血再灌注Fos蛋白表达及其意义

目的:探讨急性心肌缺血再灌注早期不同时间心肌细胞内Fos蛋白表达的变化,为心肌早期缺血再灌注损伤致死死后诊断提供新方法。方法:在32只SD大鼠建立心肌早期缺血再灌注损伤模型,另外40只大鼠分为正常与缺血对照组。用免疫组化SABC法结合图象分析研究心肌细胞核Fos蛋白的累积情况。结果:缺血30min再灌注30min后,再灌注区有部分心肌细胞核呈弱阳性着色,以后随缺血时间延长核阳性增强。缺血90min再灌注30min后核棕褐色染色最强,180min后又开始减弱。正常和单纯缺血组心肌细胞核未见有阳性反应。HE染色无明显病理改变。结论:Fos蛋白表达高峰在缺血90～180min之间,FosSABC染色法可诊断缺血30min再灌注30min或更长时间的损伤。免疫组化染色法检测心肌细胞核Fos蛋白的表达有望成为急性心肌缺血再灌注死后诊断的一种有意义的手段。     

中老年猝死病例的临床分析

对47例中老年猝死病例的临床资料进行分析。本组病例提示:(1)老年早期、男性冠心病患者,并急性或陈旧性心肌梗死或其他原因所致心室电不稳定者,应视为猝死的高危个体;(2)急性心肌梗死是猝死的最常见原因;(3)避免诱因是预防发生猝死的关键;(4)应高度重视猝死的先兆症状;(5)应高度警惕老年心脏病患者的猝死,不能认为安静状态和睡眠时间是“安全”时间,不出病房是“安全”地点。值班护士查房和巡视是发现病情的主要途径。     

Advances in Myocardial Perfusion MR Imaging: Physiological Implications,the Importance of Quantitative Analysis,and Impact on Patient Care in Coronary Artery Disease

Stress myocardial perfusion imaging (MPI) is the preferred test in patients with intermediate-to-high clinical likelihood of coronary artery disease (CAD) and can be used as a gatekeeper to avoid unnecessary revascularization. Cardiac magnetic resonance (CMR) has a number of favorable characteristics, including: (1) high spatial resolution that can delineate subendocardial ischemia; (2) comprehensive assessment of morphology, global and regional cardiac functions, tissue characterization, and coronary artery stenosis; and (3) no radiation exposure to patients. According to meta-analysis studies, the diagnostic accuracy of perfusion CMR is comparable to positron emission tomography (PET) and perfusion CT, and is better than single-photon emission CT (SPECT) when fractional flow reserve (FFR) is used as a reference standard. In addition, stress CMR has an excellent prognostic value. One meta-analysis study demonstrated the annual event rate of cardiovascular death or non-fatal myocardial infarction was 4.9% and 0.8%, respectively, in patients with positive and negative stress CMR. Quantitative assessment of perfusion CMR not only allows the objective evaluation of regional ischemia but also provides insights into the pathophysiology of microvascular disease and diffuse subclinical atherosclerosis. For accurate quantification of myocardial perfusion, saturation correction of arterial input function is important. There are two major approaches for saturation correction, one is a dual-bolus method and the other is a dual-sequence method. Absolute quantitative mapping with myocardial perfusion CMR has good accuracy in detecting coronary microvascular dysfunction. Flow measurement in the coronary sinus (CS) with phase contrast cine CMR is an alternative approach to quantify global coronary flow reserve (CFR). The measurement of global CFR by quantitative analysis of perfusion CMR or flow measurement in the CS permits assessment of microvascular disease and diffuse subclinical atherosclerosis, which may provide improved prediction of future event risk in patients with suspected or known CAD. Multi-institutional studies to validate the diagnostic and prognostic values of quantitative perfusion CMR approaches are required.     

无症状心肌缺血与心绞痛患者血浆内皮素-1变化的临床研究

目的探讨无症状心肌缺血与心绞痛患者血浆内皮素-1变化的临床意义。方法采用放射免疫法测定ET-1含量,并查心电图及超声心动图。结果SMI与对照组无显著差异,其病变程度与ET-1变化呈零相关,AP组ET-1明显高于对照组,其病变程度与ET-1变化呈正相关,治疗后ET-1降至正常水平,AP非发作期ET-1亦有显著差异。结论结果显示血浆ET-1水平可能在冠心病心肌缺血类型和临床症状等方面起作用。     

Prevalence and Correlates of Ischemic ECG Findings among Adults With and Without HIV in Tanzania

Introduction:HIV confers increased risk of myocardial infarction (MI), but there has been little study of ischemic electrocardiogram (ECG) findings among people with HIV in sub-Saharan Africa.Objectives:To compare the prevalence of ischemic ECG findings among Tanzanians with and without HIV and to identify correlates of ischemic ECG changes among Tanzanians with HIV.Methods:Consecutive adults presenting for routine HIV care at a Tanzanian clinic were enrolled. Age- and sex-matched HIV-uninfected controls were enrolled from a nearby general clinic. All participants completed a standardized health questionnaire and underwent 12-lead resting ECG testing, which was adjudicated by independent physicians. Prior MI was defined as pathologic Q-waves in contiguous leads, and myocardial ischemia was defined as ST-segment depression or T-wave inversion in contiguous leads. Pearson’s chi-squared test was used to compare the prevalence of ECG findings among those with and without HIV and multivariate logistic regression was performed to identify correlates of prior MI among all participants.Results:Of 497 participants with HIV and 497 without HIV, 272 (27.8%) were males and mean (sd) age was 45.2(12.0) years. ECG findings suggestive of prior MI (11.1% vs 2.4%, OR 4.97, 95% CI: 2.71–9.89, p < 0.001), and myocardial ischemia (18.7% vs 12.1% OR 1.67, 95% CI: 1.18–2.39, p = 0.004) were significantly more common among participants with HIV. On multivariate analysis, ECG findings suggestive of prior MI among all participants were associated with HIV infection (OR 4.73, 95% CI: 2.51–9.63, p = 0.030) and self-reported family history of MI or stroke (OR 1.96, 95% CI: 1.08–3.46, p = 0.023).Conclusions:There may be a large burden of ischemic heart disease among adults with HIV in Tanzania, and ECG findings suggestive of coronary artery disease are significantly more common among Tanzanians with HIV than those without HIV.     

Decreased door-to-balloon time in patients with ST-segment elevation myocardial infarction during the early COVID-19 pandemic in South Korea: An observational study

The coronavirus disease 2019 (COVID-19) resulted in a marked decrease in the number of patient visits for acute myocardial infarction and delayed patient response and intervention in several countries. This study evaluated the effect of the COVID-19 pandemic on the number of patients, patient response time (pain-to-door), and intervention time (door-to-balloon) for patients with ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI).Patients with STEMI or NSTEMI visiting a hospital in South Korea who underwent primary coronary intervention during the COVID-19 pandemic (January 29, 2020, to December 31, 2020) were compared with those in the equivalent period from 2018 to 2019. Patient response and intervention times were compared for the COVID-19 pandemic window (2020) and the equivalent period from 2018 to 2019.We observed no decrease in the number of patients with STEMI (P = .88) and NSTEMI (P = 1.00) during the COVID-19 pandemic compared to that in the previous years. Patient response times (STEMI: P = .39; NSTEMI: P = .59) during the overall COVID-19 pandemic period did not differ significantly. However, we identified a significant decrease in door-to-balloon time among patients with STEMI (14%; P < .01) during the early COVID-19 pandemic.We found that the number of patients with STEMI and NSTEMI was consistent during the COVID-19 pandemic and that no time delays in patient response and intervention occurred. However, the door-to-balloon time among patients with STEMI significantly reduced during the early COVID-19 pandemic, which could be attributed to decreased emergency care utilization during the early pandemic.     

Hydroxyapatite from Natural Sources for Medical Applications

The aim of this work is to study the physical-chemical, mechanical, and biocompatible properties of hydroxyapatite obtained by hydrothermal synthesis, at relatively low temperatures and high pressures, starting from natural sources (Rapana whelk shells), knowing that these properties influence the behavior of nanostructured materials in cells or tissues. Thus, hydroxyapatite nanopowders were characterized by chemical analysis, Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). In vitro studies on osteoblast cell lines (cytotoxicity and cell proliferation), as well as preliminary mechanical tests, have been performed. The results showed that the obtained powders have a crystallite size below 50 nm and particle size less than 100 nm, demonstrating that hydrothermal synthesis led to hydroxyapatite nanocrystalline powders, with a Ca:P ratio close to the stoichiometric ratio and a controlled morphology (spherical particle aggregates). The tensile strength of HAp samples sintered at 1100 °C/90 min varies between 37.6–39.1 N/mm². HAp samples sintered at 1300 °C/120 min provide better results for the investigated mechanical properties. The coefficient of friction has an appropriate value for biomechanical applications. The results of cell viability showed that the cytotoxic effect is low for all tested samples. Better cell proliferation is observed for osteoblasts grown on square samples.     

线粒体H2S供体AP39对心肌梗死大鼠心肌纤维化的影响及其与线粒体动力学的关系

目的]已有研究表明H₂S可拮抗心肌纤维化,但线粒体靶向性H₂S能否拮抗心肌梗死后心肌纤维化,且是否与调控线粒体融合与分裂有关目前并不明确。为了探究这一关系,进行了该研究。 [方法]在动物实验中予以异丙肾上腺素[ISO,50 mg/(kg·d)]腹腔注射构建SD大鼠心肌梗死模型,对各组大鼠行心电图检测,使用线粒体H₂S供体AP39[36 μg/(kg·d)],腹腔注射连续处理SD大鼠4周,使用Masson染色检测心肌纤维化情况,使用Western blot检测相关蛋白表达情况。体外实验以氯化钴(CoCl₂,800 μmol/L)诱导H9c2心肌细胞缺氧损伤,AP39(100 nmol/L)处理H9c2细胞,使用DL-炔丙基甘氨酸(PAG,2 mmol/L)抑制内源性硫化氢合成酶胱硫醚-γ-裂解酶(CSE),并通过荧光探针检测心肌细胞活性氧(ROS)的水平。 [结果]梗死大鼠心肌存在明显间质纤维化,胶原纤维大量堆积,且CSE、线粒体融合蛋白2(MFN2)表达下调,线粒体动力相关蛋白1(DRP1)表达增加,AP39干预后则可明显改善以上变化,而加入CSE抑制剂PAG则可逆转AP39的以上作用。同时在体外实验中发现,以CoCl₂诱导H9c2心肌细胞缺氧损伤时,细胞内ROS水平升高,MFN2表达下调,DRP1表达增加,AP39则可上调MFN2蛋白表达,抑制DRP1表达,降低心肌细胞ROS水平,而PAG则可逆转以上变化。 [结论]线粒体靶向性H₂S供体AP39可以改善心肌梗死大鼠心肌纤维化,且可促进线粒体融合,抑制线粒体过度分裂。     

利拉鲁肽对糖尿病心肌病大鼠心功能及心肌代谢异常的改善作用

目的]研究利拉鲁肽对糖尿病心肌病(DCM)大鼠心肌代谢物及相关代谢通路的影响。 [方法]3周龄SPF级雄性SD大鼠60只,随机抽取10只作为正常对照组,其余均采用腹腔注射链脲佐菌素联合高糖高脂饮食法建立DCM大鼠模型。DCM造模成功大鼠36只,随机分为DCM模型组(DCM组)、低剂量利拉鲁肽治疗组(LL组)、高剂量利拉鲁肽治疗组(HL组),每组各12只。LL组(100 μg/kg)和HL组(200 μg/kg)分别给予利拉鲁肽腹腔注射,每日一次,干预12周后,经超声心动图检测心功能后麻醉处死大鼠,并取心脏组织进行代谢组学检测,筛选并富集与利拉鲁肽改善DCM大鼠心肌代谢可能有关的差异代谢物及相关通路。 [结果]超声结果显示,与正常对照组相比,DCM组左心室射血分数(LVEF)、左心室短轴缩短率(LVFS)显著降低,左心室舒张早期最大血流/二尖瓣心房收缩期最大血流比值(E/A)明显升高(P＜0.05)。与DCM组相比,LL组和HL组大鼠LVEF、LVFS明显升高,E/A比值显著降低(P＜0.05),提示LL组和HL组左心室收缩和舒张功能受损明显减轻。代谢组学检测共发现395种代谢物,其中DCM组与正常对照组、LL组与DCM组、HL组与DCM组各自富集出组间差异代谢物分别为239种、116种、187种,代谢通路分别为13条、6条、20条。以上三组共交集出关键差异代谢物29种,主要涉及3条代谢通路(P＜0.05),包括胆碱代谢通路、咖啡因代谢通路以及缬氨酸、亮氨酸和异亮氨酸生物合成通路,其中胆碱代谢通路差异最为显著。 [结论]利拉鲁肽可明显改善DCM大鼠心功能及心肌代谢异常,其中胆碱代谢通路可能在利拉鲁肽改善心肌代谢保护心脏功能过程中起到关键作用。