Myocardial contrast echocardiography in ST elevation myocardial infarction: ready for prime time?

Acute myocardial infarction (AMI) continues to be a significant public health problem in industrialized countries and an increasingly significant problem in developing countries. ST elevation myocardial infarctions (STEMI) constitute approximately 40% of all AMIs with approximately 670,000 cases yearly in the United States alone. The risk of further cardiac complications such as re-infarction, sudden death, and heart failure for those who survive AMI is substantial. Thus, early assessment and risk stratification during the acute phase of STEMI is important. Furthermore, it is essential to assess the efficacy early after any initial therapeutic intervention, not only to facilitate further management, but also to enable development of new treatment algorithms/approaches to further improve the outcome. The aim of reperfusion therapy in AMI is not only to rapidly restore epicardial coronary blood flow but also to restore perfusion at the microcirculatory level. Myocardial contrast echocardiography (MCE) which utilizes microbubbles can assess myocardial perfusion in real time. Its ability to assess myocardial perfusion and function in one examination allows it to ascertain the extent of myocardial reperfusion achieved in the risk area. Furthermore, in stable patients after AMI, MCE allows assessment of LV function, residual myocardial viability, and ischaemia which are all powerful prognostic markers of outcome. Its portability, rapid acquisition and interpretation of data, and the absence of radiation exposure make it an ideal bedside technique.     

Evaluation of perfusion modes on vital organ recovery and thyroid hormone homeostasis in pediatric patients undergoing cardiopulmonary bypass

The objectives of this study were: (i) to evaluate the effects of perfusion modes (pulsatile vs. nonpulsatile) on vital organs recovery and (ii) to investigate the influences of two different perfusion modes on the homeostasis of thyroid hormones in pediatric patients undergoing cardiopulmonary bypass (CPB) procedures. Two hundred and eighty‐nine consecutive pediatric patients undergoing open heart surgery for repair of congenital heart disease were prospectively entered into the study and were randomly assigned to two groups: the pulsatile perfusion group (Group P, n = 208) and the nonpulsatile perfusion group (Group NP, n = 81). All patients received identical surgical, perfusional, and postoperative care. Study parameters included total drainage, mean urine output in the intensive care unit (ICU), intubation time, duration of ICU and hospital stay, the need for inotropic support, pre‐ and postoperative enzyme levels (ALT [alanine aminotransaminase] and AST [aspartate aminotransaminase]), c‐reactive protein, lactate, albumin, blood count (leukocytes, hematocrit, platelets), creatinine levels, and thyroid hormones (thyroid stimulating hormone [TSH], FT₃[free triiodothyronine], FT₄[free thyroxine]). All patients survived the perioperative and postoperative periods. There were no statistically significant differences in either preoperative or operative parameters between the two groups. Group P, compared to Group NP, required significantly less inotropic support, had a shorter intubation period, higher urine output in ICU, and shorter duration of ICU and hospital stay. Lower lactate levels and higher albumin levels were observed in Group P and there were no significant differences in creatinine, enzyme levels, blood counts, or drainage amounts between two groups. TSH, Total T₃, Total T₄, and FT₃, FT₄ levels were markedly reduced versus their preoperative values in both groups. FT₃ and FT₄ levels were reduced significantly further in the nonpulsatile group both during CPB and at 72 h postoperation. The results of this study confirm our opinion that pulsatile perfusion leads to better vital organ recovery and clinical outcomes in the early postoperative period as compared to nonpulsatile perfusion in pediatric patients undergoing CPB cardiac surgery. The plasma concentrations of thyroid hormones are dramatically reduced during and after CPB, but pulsatile perfusion seems to have a protective effect of thyroid hormone homeostasis compared to nonpulsatile perfusion.     

A distinct nitric oxide and adenosine A1 receptor dependent hepatic artery vasodilatatory response in the CCl4‐cirrhotic liver

Increase of portal venous vascular resistance is counteracted by decrease of hepatic arterial vascular resistance (hepatic arterial buffer response). This process is mediated by adenosine in normal livers. In cirrhosis, hepatic arterial vascular resistance is decreased but the involvement of adenosine in this process is unknown. The aim of our study was to identify the signalling pathway responsible for the decreased hepatic arterial resistance in cirrhotic livers. Methods: Cirrhosis was induced by CCl₄. Using a bivascular liver perfusion dose–response curves to adenosine of the HA were performed in the presence and the absence of pan‐adenosine blocker (8‐SPT), A1 blocker (caffeine) or nitric oxide synthase‐blocker (l ‐NMMA) after preconstriction with an α1‐agonist (methoxamine). Western blot of the HA were used to measure the density of the A1 and A2a receptors. Results: Adenosine caused a dose dependent relaxation of the hepatic artery of both cirrhotic and control animals that were blocked in both groups by 8‐SPT (P<0.02). The response to adenosine was greater in cirrhotic rats (P=0.016). Both l ‐NMMA (P=0.003) and caffeine reduced the response to adenosine in cirrhotic but not in control animals. Western blot analysis showed a higher density of A1 and a lower density of A2a receptor in cirrhotic animals (P<0.05). Conclusion: The adenosine‐induced vasodilatation of the HA is increased in cirrhotic rats suggesting a role for adenosine‐NO in the decreased hepatic arterial vascular resistance found in cirrhosis. This significantly greater response in cirrhosis by the A1 receptor follows the same pathway that is seen in hypoxic conditions in extra‐hepatic tissues.     

Lung perfusion studies after transcatheter closure of persistent ductus arteriosus with the Amplatzer duct occluder

Background : Reduced left lung perfusion has been described after transcatheter closure of the patent ductus arteriosus (PDA) with several prostheses. Although the Amplatzer ductal occluder (ADO) device is currently the most widely used occluder for closure of large‐sized PDAs, the potential consequences of flow distribution to the lungs of this device have not been completely clarified. We evaluated lung perfusion following occlusion of PDA with the ADO device. Methods : Forty‐seven patients underwent successful transcatheter PDA occlusion using the ADO device were included in this study. Lung perfusion scans were performed 6 months after the procedure. Results : Decreased perfusion to the left lung (defined as < 40% of total lung flow) was observed in 17 patients (36%), 5 of whom were low‐weight symptomatic infants. Ductal ampulla length was significantly shorter and minimal ductal diameter to ampulla diameter ratio was significantly higher in patients with decreased left lung perfusion and correlated well with left lung perfusion values (r = 0.516 and r = ?0.501, respectively). A cut‐off value of ≤5.8 mm for the ductal ampulla length and ≥1.9 for ampulla diameter to ampulla length ratio showed high sensitivity and specificity for reduced lung perfusion. Conclusions : The incidence of abnormal left lung perfusion is high 6 months after transcatheter closure of PDA with the ADO, more likely in the low weight symptomatic infants and in patients with a short duct or a relatively shallow duct having abrupt narrowing of a large ampulla. © 2010 Wiley‐Liss, Inc.     

黄连吴茱萸不同配比的大鼠在体肠吸收研究

目的:研究黄连吴茱萸不同配比的在体肠吸收,比较不同配比在不同肠段吸收系数的异同。方法:采用大鼠在体单向肠灌流模型,以HPLC测定灌流后药液浓度,考察黄连与吴茱萸不同配比对小肠吸收和转运的影响。结果:黄连吴茱萸6∶6在空肠的吸收常数比其他肠段要大,差异有显著性(P<0.05);黄连吴茱萸6∶1在空肠和回肠的吸收常数比其他肠段大,差异显著(P<0.05)。黄连吴茱萸1∶1在空肠、回肠及结肠的吸收速率常数Ka值比十二指肠大,在回肠的表观吸收系数Kapp值比其他肠段要大(P<0.05);黄连吴茱萸2∶1、黄连吴茱萸6∶1及吴茱萸单煎在回肠的吸收常数较其他肠要大(P<0.05)。在回肠中黄连吴茱萸2∶1吸收较其他2个比例药物要好(P<0.05);在结肠中黄连吴茱萸各比例吸收没有吴茱萸单煎好(P<0.05)。结论:黄连和吴茱萸无论单煎或不同比例组方在各肠段均有吸收,其中黄连∶吴茱萸为1∶1和6∶1时于空肠和回肠较易吸收;黄连∶吴茱萸为2∶1时较易于回肠吸收。     

Percoll分离法结合免疫磁珠法分离提纯人外周血中性粒细胞方法的建立

目的:探讨采用Percoll分离法结合免疫磁珠负性筛选法分离人外周血中性粒细胞的可行性.方法:采用台盼蓝染色观察活力,流式细胞仪检测荧光标记的CD62L表达阳性率.结果:分选后CD62L表达阳性细胞纯度达(95.5±2.2)％,细胞活力为(98.8±2.7)％.结论:Percoll分离法结合免疫磁珠负性筛选法分选系统提纯人外周血中性粒细胞,细胞纯度高并对细胞的生物活性无明显影响,是一种更加有效的人外周血中性粒细胞分离提纯方法.     

肺动脉灌注HTK液对肺动脉高压先心病患儿术后的肺保护作用

目的  研究体外循环期间肺动脉灌注HTK保护液对合并肺动脉高压的先心病患儿的肺保护作用。方法  将40例合并肺动脉高压的先心病患儿随机分为灌注组（体外循环+HTK液肺动脉灌注,n＝20）和对照组（体外循环, n＝20）,进行心内畸形矫治,并于麻醉前、主动脉开放时、开放后6 、12 、24h 分别抽取动脉血样,测定血清中白介素-6（IL-6）和丙二醛（MDA）的浓度,并在相应的时间点抽取动脉血样行血气分析,计算各时间点的呼吸指数（RI）及氧和指数（OI）。结果  术后两组患儿血清中IL-6和MDA的浓度较术前明显升高,但灌注组明显低于对照组（P＜0.05）。灌注组患儿术后的RI及OI明显好于对照组（P＜0.05）。结论  体外循环期间行肺动脉灌注HTK液对合并肺动脉高压的先心病患儿有一定的肺保护作用。     

中药肠吸收动力学的研究进展

肠吸收动力学是决定口服药物生物利用度的重要因素之一,在中药口服制剂的开发及评价方面有着重要作用。评价药物肠吸收动力学的方法大致可分为3类：①体外试验法;②在体试验法;③体内试验法。目前中药肠吸收研究常用的实验方法为大鼠原位肠灌注模型、Caco-2细胞模型和血药浓度法;研究热点主要集中在黄酮类、皂苷类及生物碱等单一活性成分,而中药整体或复方的研究甚少。现介绍中药肠吸收动力学的主要研究方法,以及中药肠吸收研究现状,并对存在问题及其原因进行了讨论。