经皮穴位电刺激对脑卒中患者脑局部血流量的影响

目的观察单次（1h）经皮电神经刺激（TENS）治疗对脑卒中患者即刻脑局部血流量（rCBF）的影响。方法将22例脑卒中初发患者随机分为TENS治疗组和对照组。2组患者分别接受2次单光子发射计算机断层成像（SPECT）检查，2次检查间隔1h，TENS治疗组在2次检查之间接受1h的TENS治疗，治疗部位选取偏瘫侧上肢的肩髃、曲池、外关、合谷穴以及下肢的阳陵泉、足三里、解溪和昆仑穴等8个穴位。对照组2次检查之间不做TENS治疗，仅休息1h。采用半定量值、不对称指数和变化率来分析治疗前、后患侧病灶及其周边区域以及病灶对称部位及其周边区域（镜像部位）rCBF的变化。结果单次TENS治疗后，TENS治疗组与对照组相比，放射性计数、半定量值和变化率明显增加，不对称指数明显减低，差异均有统计学意义（P〈0．05）。结论单次TENS治疗可以改善脑卒中患者患侧和健侧大脑半球的rCBF，且以改善患侧rCBF为主，推测TENS对脑卒中偏瘫患者肢体功能的改善作用可能与TENS增加rCBF，激活脑细胞的功能活动有关。     

The effect of inhaled hexamethonium bromide and atropine sulphate on airway responsiveness to histamine

The degree of protection against inhaled histamine achieved by inhalation of the ganglion blocker hexamethonium bromide plus placebo, hexamethonium plus atropine sulphate, and placebo plus placebo was examined in six atopic subjects, four of whom had current asthma. Hexamethonium was administered until there was systemic evidence of ganglionic blockade with a postural drop in blood pressure of 31 +/- 7.5 mm Hg (mean +/- SD) (p = 0.01) and an increase in heart rate of 30 +/- 3.1 bpm (mean +/- SD) (p = 0.01). Atropine was inhaled in a dose (18 mg nebulized during tidal breathing) known to produce systemic inhibition of cardiac and salivary cholinergic (muscarinic) receptors. The airway effects were measured by FEV1. Hexamethonium caused bronchoconstriction in all four subjects with asthma, which was reversed by atropine. The mean provocation concentration of histamine to provoke a 20% fall in FEV1 was 2.97 mg/ml after premedication with placebo, it was not different at 2.84 mg/ml after hexamethonium alone, and it increased slightly to 5.31 mg/ml after both hexamethonium and atropine (p = 0.06). The results suggest that the main effect of inhaled histamine is not by reflex bronchoconstriction but rather through stimulation of H1-receptors on airway smooth muscle. Therefore, histamine hyperresponsiveness in asthma is not primarily caused by a defect in the parasympathetic nervous supply to the airway.     

加速正畸牙齿移动的生物学方法

正畸治疗的平均疗程在两年以上,较长的正畸治疗周期可能增加牙周、牙体并发症发生的风险。因此科学有效地加速牙齿移动,缩短正畸周期具有重要的临床意义。目前加速牙齿移动的方法主要有两大类：一类是外科手术法,包括截骨术、皮质切开术、压电皮质切开术、微骨手术等;另一类是非手术理化刺激法,包括低能激光辐照疗法、低强度脉冲超声、共振震动、脉冲电磁场、低频脉冲疗法、化学物质局部注射等。本文对以上方法的研究进展作一综述,以期为临床医生选择加速牙齿移动的方法提供参考。     

Low nocturnal blood pressure is associated with reduced cerebral blood flow in the cohort "Men born in 1914"

BACKGROUND:

“Men born in 1914” is a population-based cohort study of the epidemiology of cardiovascular and cerebral disease. Little is known about how diurnal variation in blood pressure (BP) levels influence cerebral perfusion in very elderly populations.

OBJECTIVES:

To study the association between systolic (SBP) and diastolic BP (DBP) levels, during the day and at night, expressed through 24 h ambulatory BP monitoring (ABPM) and regional cerebral blood flow (rCBF) disturbances.

METHODS:

A cross-sectional study from a population-based cohort of 108 men 81 years of age (born in 1914) was performed in an out-patient university clinic. Cerebral blood flow measurements using ^99mTc-hexamethylpropyleneamine oxime single photon emission computed tomography and 24 h ABPM were performed. Eleven men were excluded due to incomplete ABPM data.

RESULTS:

Mean DBP at night for each tertile was correlated to rCBF for the medial temporal right (P=0.012) and left (P=0.039) regions. Also, DBP during the day was correlated to the medial temporal right region (P=0.025). When analyses were stratified for DBP during the day, subjects with high DBP during the day (greater than 70 mmHg) showed a stronger association between low medial temporal right rCBF and low mean DBP at night (r=0.32, P=0.009) compared with subjects who had a lower daytime DBP. A corresponding positive correlation was noted for the medial temporal left region and daytime SBP, whereas a negative correlation was noted for frontal left region blood flow and SBP at night.

CONCLUSIONS:

A significant association was seen between low BP levels, especially at night, and rCBF in subjects with otherwise normal daytime DBP that may indicate a risk for nocturnal cerebral ischemia.     

彩色多普勒超声诊断区域性门静脉高压症的价值

为早期诊断区域性门静脉高压症,探讨彩色多普勒超声的诊断价值。回顾性分析了经临床证实的11例患者的病史、超声学特征,分析了彩色多普勒超声诊断对于该病的诊断正确率和病因诊断符合率。结果表明,11例经彩色多普勒超声诊断的正确率为100％,病因符合率为90.9％。由于彩色多普勒超声具有简单、无创、准确等优点,应作为区域性门静脉高压症的首选诊断方法。     

Intramyocardial sustained delivery of basic fibroblast growth factor improves angiogenesis and ventricular function in a rat infarct model

 Recently we have demonstrated that the release of basic fibroblast growth factor (bFGF) from a biodegradable gelatin hydrogel carrier depends on the degradation of hydrogel in vivo. The purpose of our study was to assess whether bFGF-incorporating gelatin hydrogels induce myocardial angiogenesis and improve left ventricular function in the infarcted myocardium of rats. Studies were conducted in 22 Lewis rats after a 4-week ligation of the proximal left anterior descending coronary artery. The rats were randomized into the following two groups: the control group (n = 11) had an intramyocardial injection of saline alone, and the FGF group (n = 11) had gelatin hydrogel microspheres containing 100 μg of bFGF injected into the border zone of the infarct area after the repeat left thoracotomy. For visualization of the regional myocardial blood flow in the rat heart, ²⁰¹Tl images were taken just before and 4 weeks after the treatment using a 4-head single photon emission computed tomography scanner with pinhole collimators. Left ventricular function was also assessed with echocardiography and a micromanometer-tipped catheter. Finally, the extent of myocardial angiogenesis was evaluated quantitatively in the postmortem analysis. The ²⁰¹Tl defect score in the control group remained unchanged before and after the treatment, whereas it decreased significantly in the FGF group. Both regional and global left ventricular function was significantly better in the FGF group compared with the control group. The vascular density in the border zone of the infarct in the FGF group was significantly higher than that in the control group. In conclusion, intramyocardial injection of bFGF-impregnated gelatin hydrogels induces functionally significant angiogenesis and improves left ventricular systolic and diastolic function in the infarcted myocardium of rats. Received: July 31, 2002 / Accepted: November 22, 2002 Acknowledgment This study was supported by the “Research for the Future” Program (JSPS-RFTF 99 I 00201) from the Japan Society for the Promotion of Science, Japan.     

Splanchnic oxygen transport after cardiac surgery: evidence for inadequate tissue perfusion after stabilization of hemodynamics

Objective To evaluate the adequacy of visceral oxygen transport and gastric pH_i after open heart surgery in patients with stable hemodynamics.Design Nonrandomized control trial.Setting A general intensive care unit in a tertiary care center.Patients Sixteen postoperative cardiac surgery patients were studied after stabilization of systemic hemodynamics.Interventions The effect of dobutamine infusion (6 g kg^–1 min^–1) on systemic and regional oxygen transport was studied in ten patients, with six patients serving as controls. Systemic oxygen consumption was measured by indirect calorimetry and splanchnic and femoral blood flow, by continuous infusion of indocyanine green using regional catheters and gastric mucosal pH_i by gastric tonometer.Measurements and results Gastric mucosal acidosis was observed in half of the patients. Dobutamine increased cardiac output (3.2±0.6 vs 4.4±0.7l· min^–1·m^–2;P<0.05), splanchnic blood flow (0.68±0.28 vs 0.91±0.281· min^–1·m^–2;p<0.05) and femoral blood flow (0.25±0.08 vs 0.32±0.11l·min^–1·m^–2;p<0.05). Changes in splanchnic oxygen delivery and consumption were parallel in the two study groups. In response to dobutamine, gastric pH_i did not change (7.30±0.08 vs 7.31±0.06; NS), while in the control group, gastric pH_i tended to decrease (7.32±0.04 vs 7.28±0.06; NS). Systemic oxygen consumption increased in response to dobutamine (141±11 vs 149±11 ml· min^–1·m^–2;P<0.05) but did not change in the control group.Conclusions We conclude that a mismatch between splanchnic oxygen delivery and demand may be present despite stabilization of systemic hemodynamics after cardiac surgery. This is suggested by the parallel changes in splanchnic oxygen delivery and consumption. Dobutamine is likely to improve splanchnic tissue perfusion at this phase.This study was supported in part by the senior researcher's grant no. 1945/3015/92 to Dr. Takala from the Academy of Finland     

速度向量成像技术评价原发性高血压左心室无肥厚构型患者局部心肌功能

目的探讨VVI技术对原发性高血压患者左心室舒缩功能早期变化的预测价值。方法选取80例正常构型高血压患者(NG组)和45例向心性重构高血压患者(CR组),以80名血压正常者(NC组)为对照。常规超声测定左心室舒张末内径(LVIDd)、室间隔厚径(IVST)、左心室后壁厚径(LVPWT)、射血分数(LVEF)、二尖瓣口舒张期血流频谱E、A峰比值,在VVI条件下采集左心室短轴乳头肌水平二维图像,检测收缩期和舒张期左心室前壁、侧壁、后壁、下壁及前后间隔各节段心肌周向应变和应变率。结果 3组间LVEF值差异无统计学意义(P>0.05),CR组E/A比值低于NC组和NG组(P<0.05)。CR组局部心肌收缩期峰值应变、应变率及舒张早期局部心肌应变率均低于NC组和NG组(P<0.05);NG组舒张早期局部心肌应变率低于NC组(P<0.05),收缩期局部心肌应变和应变率与NC组相比未见明显差异(P>0.05)。3组间舒张晚期局部心肌应变率无统计学意义(P>0.05)。结论VVI技术可定量评价左心室局部功能,早期发现高血压患者局部心肌的收缩及舒张功能障碍。舒张早期局部心肌应变率减低可能是高血压患者心功能的较早期改变。     

QRS complex and ST segment manifestations of ventricular ischemia: The effect of regional slowing of ventricular activation

Objective

Reduction or interruption of the blood supply to myocardium due to occlusion of coronary artery and consequent ischemia leads to changes of electrogenesis: changes in morphology and duration of action potentials and slowing of conduction velocity in the affected area. In this study we simulated the effects of localized changes in depolarization sequence on the QRS and ST segment patterns, using computer modeling.

Methods

The model defines the geometry of cardiac ventricles analytically as parts of ellipsoids and allows changing the velocity of impulse propagation in the myocardium. An intramural electrically inactive area encircled by a transmural area with slowed impulse propagation velocity was introduced in anteroseptal and inferior locations. The effects on the QRS complex and the ST segment of the 12-lead electrocardiogram are presented.

Results

The intramural electrically inactive area caused QRS changes typical for corresponding locations of a myocardial infarction observed in patients, which were further considerably modified by slowed impulse propagation velocity in the surrounding area. Additionally, areas of slowed impulse propagation velocity led to ST segment deviations in the “reciprocal” leads, shifting the ST segment towards the affected areas.

Conclusion

Using computer modeling we showed that the localized alteration of impulse propagation not only modified the QRS complex, but produced also changes in the ST segment consistent with changes which are usually interpreted as the effect of “injury current”.