Activation of the langendorff perfused rat heart depolarized by increased external potassium concentration

Myocardial activation under depolarized conditions was studied in spontaneously beating Langendorff perfused hearts from albino rats. Depolarization was obtained by increasing external potassium concentration in steps (5.4, 7.4, 10, 10.5, 11 and 11.5 mM) in the perfusing solution with or without adrenaline (Adr). Left ventricle isovolumic systolic pressure and coronary flow did not change as external potassium increased, albeit being larger with Adr in the perfusing solution. Atrial and ventricular rates decreased, the latter showing a larger decline. The same behaviour was displayed by perfused hearts, with higher rates being developed by the group with Adr. PR interval and QRS complex duration increased as a function of external potassium. PR intervals were the same in both groups but QRS duration was larger in the Adr group, indicating that AV conduction was not changed in presence of Adr but intraventricular conduction was delayed in that situation. It was also observed that in the great majority of perfused hearts, differing from isolated preparations, ventricular mechanical activity ceased at around 11.5 mM external potassium.     

小儿先心病心电图P波,QRS波时限,振幅与左房和肺动脉压力的相关分析

小儿先心病术后左房夺和肺动脉压力的监测在ＩＣＵ中十分重要。心电图是论断和评价心脏疾患的常用方法。本文分析了３２例小儿先心病手术前后（伴肺动脉高压１６例）６个肢体导联心电图中Ｐ波和ＱＲＳ波时限总和及振幅总和与左房、肺动脉压力的关系。结果表明两者均有良好的相关性（ｒ＝０．８５￣０．８８，ｒ＝０ｍ７４￣０．８０，Ｐ〈０．０１），该法简单、方便，可广泛开展，尤其在术后未放置ＰＡ和ＬＡ管或在ＩＯＵ中已拨除Ｌ     

Acute heart failure and acute renal failure in Kawasaki disease

Acute renal failure and acute heart failure are rare in Kawasaki disease. We experienced two patients with Kawasaki disease who presented acute renal failure and acute heart failure. These two patients gave us an important insight into the understanding of water balance and fluid therapy in Kawasaki disease. One patient showed acute prerenal failure due to fluid exudation from the intravascular to the extravascular space, and subsequent acute heart failure. The other patient showed acute heart failure caused by fluid infusion for the treatment of dehydration. It is suggested that acute renal failure could be caused by a fluid shift from the intravascular to the extravascular space in Kawasaki disease. It is also demonstrated that the reserve of cardiac function could be decreased in patients with Kawasaki disease due to myocarditis even with normal echocardiography and chest X-rays.     

Hormone replacement therapy is associated with increased C-reactive protein in women with Type 2 diabetes in the Diabetes Heart Study.

AIMS: Increased levels of inflammatory biomarkers, especially C-reactive protein (CRP), are associated with increased risk for cardiovascular disease (CVD) events, such as myocardial infarction, stroke, peripheral vascular disease, and sudden cardiac death. Medical interventions that increase CRP levels, such as hormone replacement therapy (HRT) in post-menopausal women, are under increasing scrutiny. The effect of HRT on CRP levels in women with Type 2 diabetes (T2DM) is not well documented, and conflicting conclusions have been reported. The aim of this study was to determine the influence of HRT on women with diabetes in a large cross-sectional study. METHODS: Three hundred and twenty-seven post-menopausal women with T2DM from the Diabetes Heart Study participated. Current use of HRT was determined and serum CRP levels were measured using a high-sensitivity ELISA kit. Generalized estimating equation methods were used to assess the relationship of multiple clinical and lifestyle (e.g. smoking) measures on CRP levels including differences between women taking HRT (HRT+) and not taking HRT (HRT-). RESULTS: Overall serum CRP levels were strongly associated with body mass index (P < 0.0001) and age (P < 0.0001). Of the women, 243 were not using HRT and 84 were using HRT. HRT+ and HRT- women did not differ significantly in measures of clinical traits, with the exception of higher mean low-density lipoprotein cholesterol in HRT- women (P = 0.004). In all models tested, HRT+ women had significantly higher circulating CRP levels, with P-values ranging from 0.0045 to 0.010. CONCLUSIONS: In this study of serum CRP concentration as a function of HRT in women with Type 2 diabetes, there was consistent evidence for increased circulating CRP levels in women receiving oestrogen-containing HRT. Whether HRT-induced increases in CRP can account for the adverse cardiovascular effects of HRT remains to be established; however, based on these data, there is little reason to believe that diabetic women would be spared from such an effect.     

A 3-month double-blind cross-over study of the effect of benazepril and hydrochlorothiazide on functional class in symptomatic mild heart failure.

The non-sulfhydryl selective angiotensin-converting enzyme inhibitor benazepril (20 mg daily) was compared with hydrochlorothiazide (50 mg daily) in post-infarction (6-24 months) patients with symptomatic (NYHA functional class 2) mild heart failure. No concomitant drug therapy was given. The study had a double-blind cross-over design with 3-month treatment periods. Both drugs were well tolerated, and both caused a similar reduction in systolic blood pressure. Heart rate was higher with the diuretic. Benazepril improved the NYHA functional class in 17 out of 29 (59%) patients, whereas one patient improved with hydrochlorothiazide (P = 0.0004). With regard to global efficacy score, benazepril was also superior. Thus, angiotensin-converting enzyme inhibitors may be superior to diuretics as first-choice therapy in symptomatic mild heart failure.     

Heart health inequalities in Canada: modules, theory and planning

It is well known that prevalence and incidence rates of cardiovasculardisease (CVD) and CVD risk factors are not equally distributedamong socioeconomic groups. Known risk factors account for part,but not all of unequally distributed CVD rates. Socioeconomicconditions and psychosocial dynamics may explain another pareof the increased CVD rates. Theoretically, it may be possibleto lower CVD rates and CVD risk factor prevalence among lowersocioeconomic status (SES) groups by using a community development(socio-environment) strategy directed towards changes in socioenvrronmentalrisk conditions and psychosocial risk factors, rather than CVDrisk factors per Se. This article describes a protocol for sucha strategy based upon the planning work of Canadian health professionals,loosely organized under a project titled ‘Heart HealthInequalities in Canada’ This protocol incorporates baselinedata on CVD and CVD risk factor prevalence, but is premisedon actions negotiated between community organizations and healthauthorities, rather than defined unilaterally by health authorities.As such, program design activities and evaluation will differfrom a more general population-based risk factor reduction strategy.     

机械应力对幼鼠髋臼发育影响的实验研究

目的阐明异常机械应力对髋臼发育和髋臼软骨生长板内软骨细胞增殖的影响,探讨髋臼发育不良的修复方法。方法将60只3周龄的雌性Wistar大鼠分成3组,每组20只,左侧髋关节为实验侧,右侧为对照侧。A组:在2周内反复将髋关节手法脱位后再复位;B组:膝关节伸直位钢针固定,制作髋臼发育不良的动物模型,2周后拔出钢针;C组:持续伸直位固定膝关节。三组动物分别于第5、7、9、12周时进行钼靶软X线、组织形态学及透射电镜观察。结果A组第5周时唇缘变钝,髋臼角比对侧增大约5°,软骨生长板内增殖层软骨细胞极向紊乱,SO染色无差异,圆韧带有淋巴细胞浸润,第7、9、12周时变化小,两侧无差异;B组第5周时髋臼角比对侧明显增大,第7周时唇缘变钝、内翻,纤维增生,柱状细胞极性紊乱,肥大细胞层增多,第9、12周时接近正常,12周时髋臼角为23.4°,髋臼入口最短径为5.0mm;C组髋臼角比对侧持续增大,没有任何改善倾向,第12周时唇缘内翻、扁平,无明显柱状细胞排列,细胞核变小,细胞器减少,空泡形成,髋臼角为71.3°,髋臼入口最短径为2.9mm。结论在髋臼发育旺盛期解除异常机械应力、恢复头臼同心,髋臼发育不良有治愈倾向。造成髋臼发育不良的直接原因是软骨生长板内增殖层软骨细胞代谢功能发生改变,骨化延迟。     

Mechanobiology and force transduction in scars developed in darker skin types

BACKGROUND: Scarring is a complex process involving many cell types, cytokines and biological pathways including mechanobiology. Some subtle mechanical properties of skin can be assessed by measuring the speed of ultrasound shear wave propagation. The orientation of abnormal skin tension forces can be visualized, particularly in darker skin types, using dermoscopy showing distinct patterns of rete ridges' conformation. AIM: To assess some mechanobiological features of scars in darker skin types. PATIENTS AND METHODS: Large atrophic and hypertrophic surgical scars were examined on the trunk of 35 darker skin subjects. The surrounding skin was used as a comparator. Dermoscopic aspects were recorded. Resonance running time measurements (RRTM) were performed using a shear wave propagation device (Reviscometer). They were performed in four specific directions at given angles with regard to the long axis of the scar. The minimum, maximum and mean RRTM values were recorded at each site. RESULTS: Dermoscopy revealed patterns of melanin deposits in scars distinct from the normal honeycomb network seen in the surrounding skin. Hypertrophic scars showed a patchy pattern of large macular melanoderma dispersed in a lighter background. In these cases, low RRTM values were obtained with little variations according to the orientation of the measurements. By contrast, atrophic scars showed a streaky laddering melanotic pattern under dermoscopy. Higher RRTM values were often obtained, particularly in the transversal direction of the scars. Mechanical anisotropy was greater in the atrophic scars compared with the normal skin. DISCUSSION: Darker skin types represent a model for visualizing the main orientation of the epidermal rete ridges. A correlation was found between the pattern of melanized rete ridges of scars and the main orientation of the intrinsic forces in the skin.     

完全胸腔镜下心内直视手术的实验研究

目的　探索完全胸腔镜下心内直视手术可行性手术过程中的可能风险。方法　选取 6 0支杂种成年狗 ,雌雄不拘 ,按手术前后顺序分为A、B、C三组 ,每组 2 0例 ,行完全胸腔镜下心内直视手术。记录每例手术时间、术中出现的意外损伤 ,对各组结果进行比较。结果　手术平均时间分别为 :A组 (5 6± 1 2 )h ,B组 (3 4± 0 8)h ,C组 (2 1± 0 3)h ;手术失败三组分别为 3、0、0例 ;三组实验动物意外损伤发生率 ,A组明显高于B、C组 (P <0 0 5和 0 0 1) ,分别为 2 4、8、1处。结论　经过一定时间技能训练 ,行完全胸腔镜下心内直视手术是可行的