Hippocampal EEG responses induced by carbachol and atropine infusions into the septum and the hippocampus in the urethane-anaesthetized rat

Infusion of 1 μg of carbachol, a potent cholinergic agonist, into the lateral septum of the urethane-anaesthetized rat systematically caused the induction of clear-cut hippocampal theta (θ). However, infusion of an equivalent amount of the drug into the hippocampus, close to the recording electrode, failed to induce θ in 50% of the animals and produced a mixture of θ waves and desynchronized activity, resulting in atypical EEG patterns, in the remaining subjects. Both carbachol EEG effects were blocked by intraseptal infusion of the antimuscarinic agent, atropine. Our data demontrate that muscarinic receptors in the septum are predominent sites for cholinergic agonist-antagonist action capable of generating or suppressing hippocampal θ in the rat. They also indicate that intraseptal cholinergic mechanisms play an important role in the initiation and generation of this rhythm.     

Twenty-four-hour ambulatory blood pressure profiles in pediatric patients after renal transplantation

Ambulatory blood pressure monitoring was applied in 27 pediatric patients aged 6.3 – 24.3 (median 15.0) years who had been transplanted 1.5 – 8.4 years previously. Daytime values were compared with the mean of 10 concomitant casual blood pressure recordings. At the time of the study, antihypertensive drugs were given to 17 patients. Inulin clearance ranged from 18 to 116 (median 66) ml/min per 1.73 m². Ambulatory blood pressure monitoring confirmed hypertension or normotension determined by casual blood pressure measurements in 63% of patients. The physiological nocturnal dip in blood pressure was attenuated or reversed in 8 of 27 patients. It was reduced in all 3 patients with renal artery stenosis of the graft, in 3 of 4 patients with chronic rejection, in the only patient with recurrent focal segmental glomerulosclerosis, and in 1 of 6 patients with past acute rejection. The dipping was not related to inulin clearance. In conclusion, casual blood pressure measurements do not accurately reflect blood pressure in pediatric patients transplanted more than 1.5 years previously. A reduced nocturnal dip in blood pressure may indicate an underlying renovascular or renoparenchymal pathology. Ambulatory blood pressure monitoring should regularly be applied in patients with renal transplants. Received May 23, 1995; received in revised form June 18, 1996; accepted June 20, 1996     

The Cardiac Pacemaker Current if

Pacemaker Current if. Since the hyperpolarization-activated current, if, was originally associated with the diastolic depolarization phase of action potential in the sinoatrial (SA) node in 1979, its central role in the generation and control of pacemaker activity has become increasingly clear through a series of experimental findings, some of which have substantially modified the pre-existing theories of cardiac pacemaking and its modulation by the autonomic transmitters. Thus, the pacemaker current of Purkinje fibers, formerly described as a deactivating pure potassium (K) current, was found to be in fact, like the nodal if, inward and activating on hyperpolarization. Furthermore, in SA node cells, as well as mediating rhythm acceleration induced by catecholamines, if was found to underlie the slowing effect of low acetylcholine (ACh) concentrations, in contrast with the generally accepted hypothesis that activation of a K conductance is the main process responsible for cardiac slowing. A final, atypical property of if recently demonstrated concerns the activating action exerted on if by intracellular cAMP. Unlike that on other voltage-gated, cAMP-modulated cardiac channels, this action is independent of phosphorylation and involves a direct binding of cAMP to if channels. (J Cardiovasc Electrophysiol, Vol. 3, pp. 334–344, August 1992)     

血压变异与心率变异及心电异常相关性分析

目的：研究血压变异(BPV)与心率变异(HRV)及心电图(ECG)异常相关性，方法：对157例未经治疗的早期高血压患者及167例未服过影响血压及心率药物的正常人，进行BPV、HRV及ECG异常的相关分析，各种数据在同一时刻得到，结果：当血压昼夜节律消失(非杓型)，BPV及HRV不正常，ECG异常明显高于其他组，当高血压患者血压昼夜节律存在时HRV各项指标接近正常，ECG异常率较低，HRV降低与血压负荷升高呈明显正相关，与心电异常也呈明显正相关，结论：对高血压治疗的目的。不仅仅是降压，还应尽量恢复昼夜血压的规律性，降低夜间血压负荷，调节植物神经功能，对于血压正常的患者。血压昼夜节律消失也应投以关照给予植物神经功能调节，达到或降低靶器官损伤或延缓靶器官损害的目的，提高患者的生活质量。     

Application of in vivo microdialysis to pineal research in birds: Measurement of circadian rhythms of melatonin

Circadian rhythms of pineal melatonin release were measured in free-moving pigeons, Japanese quails, and chickens under light-dark cycles followed by constant dim light. Although melatonin levels differed among individual birds, circadian rhythms of melatonin were observed in all of them. Using this technique, we could examine phase shifts of melatonin rhythms and suppression of melatonin release by photic stimulation in pigeons. We could also examine effects of norepinephrine infusion on melatonin release. These results indicate that microdialysis is useful for the study of pineal melatonin rhythms in birds.     

中西医结合治疗肺心病心律失常40例疗效观察

为提高肺心病心律失常的临床疗效,采用中药清肺化痰活血剂配合抗菌素及氧疗法对40例肺心病并发心律失常患者进行了治疗观察,同时与单纯使用抗菌素及氧疗法治疗的40例患者进行对照。临床以心电图改善情况为观察指标,结果两组有效率分别为87.5％和67.5％。Ridit分析结果表明,治疗组疗效明显优于对照组,经显著性检验,两组差异显著(P<0.05)。     

Modulation of cutaneous reflexes in arm muscles during walking: further evidence of similar control mechanisms for rhythmic human arm and leg movements

Stimulation of cutaneous nerves innervating the hand evokes prominent reflexes in many arm muscles during arm cycling. We hypothesized that the mechanisms controlling reflex modulation during the rhythmic arm swing of walking would be similar to that documented during arm cycling. Thus, we expected cutaneous reflexes to be modulated by position in the walking cycle (phase dependence) and be different when walking compared to contraction while standing (task dependence). Subjects performed static postures similar to those occurring during walking and also walked on a treadmill while the superficial radial nerve was electrically stimulated pseudorandomly throughout the step cycle. EMG was recorded bilaterally from upper limb muscles and kinematic recordings were obtained from the elbow and shoulder joints. Step cycle information was obtained from force-sensing insoles. Analysis was conducted after averaging contingent upon the occurrence of stimulation in the step cycle. Phase-dependent modulation of cutaneous reflexes at early (~50–80 ms) and middle (~80–120 ms) latencies was observed. Coordinated bilateral reflexes were seen in posterior deltoid and triceps brachii muscles. Task dependency was seen in that reflex amplitude was only correlated with background EMG during static contraction (75% of comparisons for both early and middle latency reflexes). During walking, no significant relationship between reflex amplitude and background EMG level was found. The results show that cutaneous reflex modulation during rhythmic upper limb movement is similar to that seen during arm cycling and to that observed in leg muscles during locomotion. These results add to the evidence that, during cyclical movements of the arms and legs, similar neural mechanisms observed only during movement (e.g. central pattern generators) control reflex output. Electronic Publication     

MEG Characterization of Spontaneous Alpha Rhythm in the Human Brain

The present piece of research studied the spontaneous alpha rhythm of the human brain by combining the use of a whole-cortex neuromagnetometer and Magnetic Resonance Imaging. Single trials of spontaneous brain activity were recorded from ten human subjects asked to rest, with their eyes either closed or open, in relaxed wakefulness. MEG measurements were conducted over a period of one and a half years. The replicability of the results was confirmed for eight subjects out of ten. For three subjects, the alpha rhythm did not show any reductions due to the opening of the eyes. Both field map pattern and location of the estimated source were persistently stationary during each of the bursts of oscillations of the alpha rhythm. Dipoles were concentrated in clusters, indicating the existence of several spatially distributed sources. The calcarine fissure, the parieto-occipital sulcus and the surrounding occipital and parieto-occipital areas were identified as cortical sites of the brain where the alpha rhythm may originate. For four subjects, the majority of the sources were located near or in the calcarine fissure, while for five subjects, they were located near or in the parieto-occipital sulcus and for the remaining subject they were equally divided between the two generation sites.     

Diurnal changes of thermoregulatory functions in pigeons

In pigeons, we studied the diurnal variation of body temperatures and its dependence on the diurnal variations of shivering, vasomotor activity and panting in light-dark (LD) — conditions (1212 h, 1001 Lux) and in different, but for at least 24 h constant ambient temperatures.In low ambient temperatures (below thermoneutrality) shivering was reduced shortly after lights off (early dark phase), and it increased again some hours before lights on (late dark phase); the lower the ambient temperature, the larger the reduction of shivering and the shorter the time of reduction.Within thermoneutrality, the decrease ofT _b in the early dark phase was associated with an increase of foot skin temperature, probably due to vasodilatation. Later-on foot skin temperature decreased again (vasoconstriction). The feet remained constricted even in the late dark phase, whenT _b already increased.At higher ambient temperature (above thermoneutrality) vasodilatation persisted all over the 24 h, while in these conditions respiratory rate increased significantly after lights off.The described diurnal variations of thermoregulatory effector mechanisms are in agreement with the concept of an active adjustment of the body temperature rhythm.Supported by the Deutsche Forschungsgemeinschaft (SBF 114)     

心肌梗死患者窦性心律震荡的检测及其临床意义

目的：探讨心肌梗死（心梗）患者窦性心律震荡检测的临床意义。方法：测定24小时动态心电监测的170例心梗患者和116例正常人室性早搏（室早）后的震荡初始（TO）和震荡斜率（TS）值及平均值，并进行对比分析。结果：心梗患者室早后的TO值明显高于对照组、鸭值明显低于对照组（P〈0．05和P〈0．01），TO和／或TS异常组死亡率明显高于TO和鸭均正常组（P〈0．001）。结论：心梗后患者窦性心律震荡现象减弱或消失时，其猝死的发生率增高，及时检测心梗患者室早后的TO和TS值，对发生猝死的高危患者的检出、危险度分层以及对其进行干预治疗都有重要的临床意义。