A型肉毒毒素对离体豚鼠心脏的抑制作用

本实验用Langendorff法,在恒温、恒液压(灌流压)和供给足够氧气的条件下,对豚鼠(Cavin porcellus)离体心脏进行灌流,以心肌收缩力、心跳频率、心电图和冠脉流量为观察指标,对照观察A型肉毒毒素对心脏活动的影响。结果发现:A型肉毒毒素可使(1)心肌收缩力减弱;(2)心跳频率减慢,甚至停搏;(3)冠脉流量减少;(4)心电图有异常改变,显示对心脏起搏有阻遏现象.     

Spectrum of looping disturbances in stage 34 chicken hearts after retinoic acid treatment

Background: In a recently developed chick model the teratogen retinoic acid has appeared to induce a spectrum of double outlet right ventricle, which needs further detailed evaluation. It is known that retionic acid is able to induce cardiac malformations. Although the exact mechanism is not known, an interaction with neural crest cell function is thought to exist. Methods: After treatment with 1 μg all-trans retinoic acid at Hamburger and Hamilton stage 15 and reincubation until stage 34 of development 41 chicken embryos were evaluated macroscopically and microscopically, supported by graphic reconstructions. These retinoic acid treated embryos were compared with a control group (n = 8). Results: The retinoic acid treated embryos could be divided in three groups. Group 1 (23/41) had an intact septum, group 2 (11/41) had an isolated ventricular septal defect (VSD), and group 3 (7/41) had a double outlet right ventricle (DORV). Besides, in the group with an intact septum 11 hearts showed an abnormal course of the subaortic outflow tract. In the group with DORV a straddling tricuspid orifice (7/8) and a double inlet left ventricle (1/8) could be distinguished. Considering the external contour, the hearts in the DORV group all showed a dextroposed arterial pole. Malformed pharyngeal arch arteries were found in all three groups (11/41) and with a great diversity. Conclusions: The present cardiac malformations in the chicken as a result of retinoic acid treatment are part of a continuous spectrum, varying from hearts with an intact ventricular septum and a normal course of the subaortic outflow tract to a double outlet right ventricle with a straddling tricuspid orifice or even a double inlet left ventricle. A remarkable observation in this spectrum concerns the correlation of malformations of the inflow and outflow tracts, which is explained as a cardiac looping disturbance. The disturbance of the looping process seems to lead to malalignment of septal components, although, in the chick, retinoic acid does not in general interfere with the formation of these septal components themselves. © 1995 Wiley-Liss, Inc.     

Heart rate analysis in 24 patients treated with 150 mg amitriptyline per day

Twenty-four patients treated with 150 mg amitriptyline per day for an episode of major depression underwent a standardized heart rate analysis (HRA) before therapy and after 14 days. The battery of cardiovascular reflex tests included the determination of the coefficient of variation (CV) while resting and during deep respiration, a spectral analysis of heart rate, the heart rate response to standing, and the Valsalva manoeuvre. The results of the initial HRA did not differ from a group of 24 normal control subjects matched for age and sex. On day 14 of treatment the patients showed significantly reduced values of heart rate variability in all tests (P<0.0001), probably due to the anticholinergic side effects of amitriptyline. Heart rate increased form 78.1 to 93.6 bpm on average (P<0.0001). Abnormal CV at rest was registered in 96% of the patients; during deep respiration 29% showed abnormal CV results. An abnormal spectral analysis was found in 100% of the cases (low frequency peak: 42%, mid-frequency peak: 100%, high frequency peak: 79%). The heart rate response to standing was abnormal in 75% and the Valsalva test in 33% of the cases. Eighty-eight percent of the patients fulfilled the criteria of a cardiovascular autonomic neuropathy under the conditions of amitriptyline therapy. As yet, the consequences of these changes for the patients have not been sufficiently elucidated.     

Inhibition of rat heart allograft rejection by a PUVA treatment of the graft recipient

Treatment of rat heart grafts with PUVA, the combination of the photosensitizer 8-methoxypsoralen and longwave ultraviolet light, leads to a prolonged transplant survival in allogeneic recipients. A PUVA treatment of the recipient rats, performed for 7 consecutive days after transplantation, prolonged graft survival even more effectively. This may be due to the systemic immunomodulatory effects of PUVA in the recipient. One of the mediators is urocanic acid, which is transformed by ultraviolet light in the skin from its trans- to the cis-isomer, which, in turn, acts as a mediator on the immune system. An injection of cisurocanic acid into graft recipients for 7 consecutive days after transplantation resulted in prolonged graft survival; in 40% of the rats, permanent graft acceptance was observed. The significance of these results for clinical organ transplantation is discussed.     

The chronotropic effect of acetylcholine in the presence of vecuronium and atracurium A study in the isolated perfused rabbit heart

The bradycardia produced by 1 microgram acetylcholine in the isolated perfused rabbit heart, in the presence of vecuronium and atracurium, was studied and compared with control. Vecuronium at a concentration of 2.5 micrograms/litre and atracurium 6 micrograms/litre did not enhance the negative chronotropic effect of acetylcholine. Atracurium produced a statistically significant inhibition of the negative chronotropic effect of acetylcholine.     

MHPG and heart rate as correlates of nonresponse to drug therapy in panic disorder patients

Little is known about biological predictors of treatment response in panic disorder (PD). In the present study heart rate, blood pressure, plasma cortisol and plasma MHPG were investigated at baseline in a sample of 44 PD patients as possible predictors for nonresponse to treatment. We used a strict definition of nonresponse to find patients who did not respond at all after 12 weeks of treatment with brofaromine or fluvoxamine. Patients were considered nonresponders when they fulfilled two criteria: they did not show a 50% reduction of agoraphobic avoidance and they still experienced panic attacks at endpoint. The variables that differed significantly between the groups were used to predict nonresponse to drug therapy. Using this strict definition of nonresponse, 15 patients (32.6%) were considered nonresponders. These patients were characterised by a higher plasma MHPG concentration and a higher heart rate at baseline. These variables were subsequently used to predict nonresponse.     

低温保存同种心脏瓣膜活性及临床应用的研究

取正常成人心脏瓣膜３６个，置于低浓度广谱抗生素的营养液（ＲＰ－ＭＩ１６４０细胞培养液）中灭菌４８ｈ，－８０℃冰箱初冻，置于液氮中长期保存。灭菌前后瓣膜细菌培养阴性率分别为９４．３％和１００％，解冻后经光镜、电镜检查证实瓣组织细胞结构正常，组织培养葡萄糖消耗率测定示瓣组织存活良好。临床同种心脏瓣膜原位移植３例，随访６～３０个月，瓣功能良好     

β受体阻滞在心血管疾病中的临床应用研究进展

依据国内外的临床研究和循证医学分析,对β受体阻滞剂在心血管疾病方面的合理应用以及适应证,给药方法进行循证性举证,提示β受体阻滞剂可明显改善心血管疾病的临床预后,除非有禁忌证及不能酎受者,β受体阻滞剂应作为心血管疾病的常规治疗病物广泛应用于心血管疾病。     

山莨菪碱对梗阻性黄疸心脏的保护作用

目的 观察梗阻性黄疸时山莨菪碱对心脏的保护作用。方法将30只成年Wistar大鼠随机分为假手术组和梗阻性黄疸模型组;模型组包括山莨菪碱治疗组,生理盐水对照组。分别于术后第14、28天测定各组血浆内毒素含量,观察心肌病理、酶组织化学和心率改变及山莨菪碱治疗后的变化。结果生理盐水对照组血浆内毒素水平明显升高,心肌出现变性、局灶坏死、线粒体破损等病理改变,心肌组织琥珀酸脱氢酶、腺苷三磷酸酶活性明显降低(P<0.05),而酸性磷酸酶活性明显增强(P<0.05),心率明显减缓(P<0.05),山莨菪碱治疗组则以上情况均有明显改善(P>0.05)。结论 山莨菪碱对梗阻性黄疸时心脏有保护作用。     

血小板活化状态在先天性心脏病中的作用

目的：研究血小板的活化状态在先天性心脏病中的作用。方法：采用流式细胞术测定P选择素的表达作为血小板活化的特异性指标，患者分为非紫绀组32例、紫绀组9例、健康对照组12例．研究先天性心脏病患者血小板活化功能的变化。结果：与健康对照组相比，非紫绀组和紫绀组先天性心脏病患者P选择素的表达均明显升高，紫绀组尤为显著。结论：先天性心脏病患者存在血小板的活化状态，紫绀型先天性心脏病更明显，这可能是引起这些患者止血功能异常的原因之一。