Observations on intra-uterine resting-phase pressure in at term pregnancy in different body positions

Investigations were conducted into the influence of body position on intra-uterine resting phase pressure in women in labour. A micro pressure sensor was placed in the uterus and rectum of 14 women immediately after artificial rupture of the fetal membranes. A significant increase in the intra-uterine resting-phase pressure was experienced when the body position was changed from supine to sitting and also from supine to standing. The intrarectal pressure, a parameter of the intra-abdominal pressure, also showed this significant increase by the same magnitude. The increased resing-phase pressure in the uterus, when the women are in a standing or sitting position, is therefore the result of extra-uterine factors.     

Changing Trends in Therapy Delivery with a Third Generation Noncommitted Implantable Defibrillator: Results of a Large Single Center Clinical Trial

Thirty-four patients underwent implantation of a third generation ICD, the 4210 ATP, for sudden cardiac death or ventricular tachycardia. This device incorporates significant telemetry logs as well as a detailed analysis of each arrhythmia episode detected. During the period of clinical follow-up, a mean of 12.2 months, a total of 26,569 VT or VF detections were made. The vast majority of these were either due to atrial fibrillation, nonsustained VT, or "noise" detection, and only 6% led to device therapy. ATP was successful in 86.3% of episodes, with 3.5% accelerations and 2.4% failure of ATP trains. The majority of inappropriate therapy episodes were clustered in seven patients, and all were easily diagnosed with the aid of the extensive telemetry Jogs and sense histories. Of five late deaths, three were from congestive heart failure, one from cerebrovascular accident, and one unknown. These data reveal that this "tiered" therapy noncommitted ICD performs to expectations; the stored data is of significant value in diagnosing the cause of ICD therapy. In addition, ATP is an effective modality for termination of VT.     

Kinetics of Clonazepam in Relation to Electroencephalographic and Clinical Effects

The aim of this study was to see if the immediate EEG and clinical response to an intravenous dose of clonazepam was predictive for the effect of oral clonazepam maintenance therapy. Four children with petit mal epilepsy were given clonazepam intravenously during continuous EEG recording. Clonazepam plasma concentrations were determined repeatedly with a high performance liquid chromatographic method using a reversed phase system. The day after the intravenous dose the patients were given oral therapy with clonazepam. Repeated long-term EEG recordings were made and plasma concentrations of clonazepam were determined. There was no clinically satisfactory effect of clonazepam during oral maintenance treatment in three of the children who responded well to the intravenous dose of clonazepam. Thus, the immediate response to intravenous clonazepam was not a good predictor of the long-term effects in our patients.     

The electrocardiogram of sheep,monitored by radiotelemetry,during electrical or carbon-dioxide stunning and subsequent slaughter

The e.c.g., monitored by telemetry, was used to study changes in the heart activity of sheep bled out after electrical stunning or carbon-dioxide anaesthesia. The decrease in ventricular rate which occurs as sheep are bled out after electrical stunning is apparently attributable to increasingly severe anoxia, rather than to changes in blood pressure. The heart rate at sticking is directly related to the heart rate before electrical stunning, but no relationship was found between the wattseconds used and the heart rate at sticking. However, the greater the number of wattseconds applied, the lower the minimum heart rate recorded after sticking. Exposure to carbon dioxide caused an initial tachycardia, followed by a decreased heart rate and then a secondary increase. The rate rose further when the sheep were removed from the gas. As the percentage of carbon dioxide used increased, the duration of heart activity after sticking decreased. Since high stunning currents cause early atrioventricular block, they might adversely affect bleeding out, if this is dependent on heart activity. High concentrations of carbon dioxide results in earlier termination of heart activity and might affect bleeding out similarly. The lower heart rate of sheep before electrical stunning may indicate that it is inherently less stressful than carbon-dioxide anaesthesia and so less likely to affect meat quality.     

The effect of telemetry on urban prehospital cardiac care

A three-year, controlled trial of the use of telemetry in the prehospital care of cardiac patients was conducted in a major metropolitan area. Five of the ten paramedic squads in the city used telemetry; the other five squads did not. We studied the effect of telemetry on the following: paramedics' abilities to recognize ECGs in a written test; paramedics' abilities to identify ECG arrhythmias in the field; length of time spent by paramedics in the field; survival rates of patients with ventricular fibrillation (VF) cared for by paramedics; abilities of base station physicians to interpret telemetered ECGs; and attitudes of paramedics toward using telemetry. Telemetry was not found to affect the abilities of paramedics to read ECGs in either test or field situations. Paramedics who used telemetry spent more time in the field with their patients than did paramedics who did not use telemetry (P less than .02). We found no statistically significant effect of telemetry on survival rates of VF patients. Using matched ECGs, readings by base station physicians were found to be more accurate than were those by paramedics (P less than .01). Paramedics overwhelmingly reported that telemetry did not help them to save patients' lives, but that it did help them to treat patients with certain arrhythmias. The results suggest that telemetry may not improve either paramedics' abilities to identify arrhythmias or prehospital care for all cardiac patients. The implications for emergency services researchers are discussed.     

Is heart rate an indicator of imprinted preferences and affect?

Different tests for “imprinted” preferences may produce discordant results. To resolve this enigma, measurements of changes in heart rate were recorded in the presence of the familiar imprinted and an unfamiliar object. The character of the changes in cardiac activity varied in an apparently haphazard fashion, nor did constraints on locomotion alter this picture. It is not known whether these considerable and seemingly spontaneous changes in cardiac activity are common to the young of all birds, or unique to ducklings. The underlying causes and their biological significance may pose a problem of greater importance than the presumed (and still unproven) relation between imprinting, heart rate, and affect.     

基于无线能量传输技术的植入式三路心电遥测系统

目的 为全方位监测心电信号并弥补单一导联心电检测的不足,设计并实现了一种基于无线能量传输技术的植入式三路心电遥测系统.方法 系统由无线能量传输设备供能,植入式微型电子胶囊检测心电信号,数据记录仪无线接收数据并由数据处理软件处理.直流供电下分别采用模拟心电信号、正弦信号、方波信号通过模拟实验验证了系统的性能.无线供能下信号线屏蔽后并埋在猪肉中进行体外实验.结果 模拟实验胶囊能够采集三种信号,体外实验测得有噪声的信号波形.结论 直流供电下胶囊正常工作,无线供能下猪肉对磁场有一定程度的屏蔽作用.     

Event-recorder monitoring in the diagnosis of atrial fibrillation in symptomatic patients: subanalysis of the SOPAT trial

In the SOPAT (suppression of paroxysmal atrial tachyarrhythmias) trial, a high number of asymptomatic atrial fibrillation (AF) episodes were registered in patients with symptomatic AF. This subanalysis was performed to answer three questions: (1) Does antiarrhythmic therapy influence the ratio of symptomatic to asymptomatic AF? (2) Are symptoms during AF dependent on the heart rate (HR)? (3) Do symptoms correlate with an episode of AF? Within 60 months 1,033 patients with symptomatic AF were randomized to either quinidine plus verapamil (Q+V) 480/240 mg/day, Q+V 320/160 mg/day, sotalol 320 mg/day, or placebo, and followed up by daily and symptom‐triggered ECG event recording. Over 188,634 ECGs were analyzed (87% SR, 7% AF). Symptoms were reported in only 46% of AF‐ECGs. Quinidine plus verapamil reduced the ratio of symptomatic to asymptomatic AF, whereas sotalol had no effect (median [%] (25/75% quartile): Q+V 480/240: 33 (0/79), Q+V 320/160: 45 (1/82), sotalol: 56 (7/93), placebo: 63 (8/92)). The HR during AF directly correlates with the occurrence of symptoms (P < 0.001) and was significantly lower during asymptomatic AF in all groups (mean ± SD: sympt.: 113 ± 27/minute, asympt.: 103 ± 27/minute, P < 0.001). Both antiarrhythmics reduced the mean HR compared to placebo (P < 0.001). Analyzing all symptom‐triggered ECGs, AF was diagnosed in only 37%, whereas the majority were SR. Taken together, in contrast to sotalol, Q+V reduces the ratio of symptomatic to asymptomatic AF compared with placebo, at least in part by decreasing the heart rate. Furthermore, patients' symptoms are not a reliable surrogate parameter for the prevalence of AF.     

Tonic activity of alpha1 adrenergic receptors of the medial preoptic area contributes towards increased sleep in rats

Several studies have suggested that noradrenergic afferents to the medial preoptic area might be involved in hypnogenesis and in lowering the body temperature, and that the alpha1 adrenergic receptors might be mediating these responses. This study was undertaken to find out the changes in sleep-wakefulness and body temperature in rats, when these adrenergic receptors of the medial preoptic area are blocked by alpha1 selective antagonist, prazosin. Adult male Wistar rats were chronically implanted with electrooculogram, electroencephalogram and electromyogram electrodes for sleep-wakefulness assessment, and a bilateral guide cannula for microinjection of prazosin at the medial preoptic area. A radio-transmitter was implanted in the abdomen for telemetric measurement of body temperature in four groups of rats. Sleep-wakefulness was also assessed telemetrically in four other groups of rats. Sleep-wakefulness recordings from these rats were done in a specialized chamber, where they could move about freely and select the ambient temperature which they prefer. Prazosin induced a dose dependent increase in wake period and in body temperature, when microinjected into the medial preoptic area. Results suggest that preoptic alpha1 adrenergic receptors mediate hypnogenic and hypothermic responses. It is proposed that the noradrenergic afferents to the medial preoptic area, by tonic activation of alpha1 adrenergic receptors, contribute towards increase in sleep especially during the daytime.     

药物安全药理学研究新进展

［摘要］　安全药理学主要研究药物及其代谢产物对心血管系统、呼吸系统和中枢神经系统等的影响。通过安全药理学研究,确定药物可能关系到人安全性的非期望药理作用;评价药物在毒理学和/或临床研究中所观察到的药物不良反应和/或病理生理作用;研究所观察到的和可疑的药物不良反应机制。近年来安全药理学研究发展迅速,生物信号遥测系统可用来检测清醒状态下、自由活动动物的多种生理指标;对药物引起的QT间期延长应进行综合风险评估已是共识;计算机毒性预测、人心肌干细胞研究、下丘脑病理组织切片研究、用斑马鱼进行高通量筛选、安全药理学生物标志物探索为准确预测药物的临床毒性奠定了基础。