Effects of Vagal and Sympathetic Nerves on Transmembrane Potential of Cardiac Ventricular Cells of Toad

The effects of vagal and sympathetic nerves on the transmembranepotentials of cardiac cells of toad were observed by means of microelectrodetechnique.The vagal nerve was stimulated there would be an increase in restingpotential and acceleration in repolarization of action potential(AP).However,ifatropine was used before stimulation the above-mentioned phenomena woulddisappear.When the sympathetic nerve was stimulated the AP amplitudeincreased,but resting potential(RP)remained the same.The increase of APresulted from the increases of overshoot.When the sympathetic nerve wasstimulated although the heart rate increased and the duration of AP wasshortened,the plateau phase of AP was prolonged.These results suggest that theeffects of vagal and sympathetic nerves on the transmembrane potential of cardiacventricular cells are coordinated and the normal characteritics of transmembranepotential are maintained by both the vagal and sympathetic nerves.     

基底节脑出血开颅手术与钻颅抽吸治疗的疗效比较（附136例报告）

目的比较基底节脑出血开颅手术治疗与钻颅抽吸治疗的有效性与安全性。方法回顾性分析我院近5年来基底节出血行外科开颅治疗和钻颅抽吸治疗的所有病例，应用统计学方法进行疗效比较。结果共136例基底节出血病例，其中30例行外科开颅清除血肿治疗，106例行钻颅抽吸治疗。两组病例在年龄、出血量、意识状态等预后影响因素方面差异无统计学意义（P〉0．05）。基底节出血开颅手术治疗有效性与安全性与钻颅抽吸治疗相比差异无统计学意义（P〉0．05）。结论基底节出血外科开颅治疗有效性与安全性并不优于钻颅抽吸治疗。     

Distribution and origin of serotoninergic afferents to guinea pig cochlear nucleus

The distribution of serotoninergic fibers in the guinea pig cochlear nucleus was studied with serotonin immunohistochemistry. In addition, the origin of the serotoninergic fibers was determined by combining the retrograde transport of wheat germ agglutinin-apohorseradish peroxidase (gold conjugated) with serotonin immunohistochemistry. Immunoreactivity was present in varicose and nonvaricose fibers that were unevenly distributed throughout the cochlear nucleus. The fibers were most prominent in the superficial layers of the dorsal cochlear nucleus and the anterior spherical cell area of the anteroventral cochlear nucleus. Although less prominent, serotonin-positive fibers were also present in the remaining part of the anteroventral cochlear nucleus and the posteroventral cochlear nucleus. A few positive fibers were present in the auditory nerve root and the dorsal and intermediate acoustic stiae. Double-labeled cells were found throughout the rostral- caudal extent of the serotoninergic system from the caudal linear nucleus to the nucleus raphe pallidus. However, most were confined to the dorsal (52%) and median (18%) raphe nuclei. Some serotoninergic cell groups contained retrogradely labeled cells that were not serotonin immunoreactive, indicating nonauditory afferents to cochlear nucleus containing other neurotransmitter substances. Serotonin may tonically modulate auditory processing within the cochlear nucleus as well as influence certain ascending auditory pathways. Most of the serotonin in the cochlear nucleus comes from superior raphe nuclei that also project to basal ganglia motor systems and limbic strctures. Therefore, the effect of serotonin on the cochlear nucleus may be related to level of arousal or behavioral state. © 1995 Willy-Liss, Inc.     

Calcium and other salivary factors in periodontitis-affected subjects prior to treatment

Abstract Salivary calcium was shown to be higher in treated periodontitis-affected subjects (P+) than in periodontitis-free patients (P?). Here the aim was to study whether differences in calcium or other salivary factors exist prior to treatment. The test group consisted of 20 (15 men, 5 women) periodontitis-affected subjects and the control group 15 subjects (10 men, 5 women) free from periodontitis. Paraffin-stimulated whole saliva was collected to determine the flow-rate, calcium and phosphate concentrations, pH, buffering capacity, numbers of mutans streptococci, lactobacilli and yeasts. The results showed a higher calcium concentration (p < 0.05) in the P+ group (x?: 1.68 mmol/l; SE: 0.06 in men and x?: 1.49 mmol/l; SE: 0.10 in women) than in the P-group (x?: 1.48 mmol/l; SE: 0.09 in men and x?: 1.18 mmol/l; SE: 0.10 in women). The P+ group had more intact teeth (x?±SE: 9.9±0.8 in men and 11.2±2.0 in women) than the P-group (x?± SE: 8.3±0.7 in men and 8.2±2.4 in women). The present findings may indicate that an elevated level of salivary Ca is characteristic of P+ patients both before and after periodontal treatment.     

试论门诊管理

结合门诊管理的实践,对如何加强门诊管理进行了论述。主要为:①掌握门诊特点,确定门诊管理重点;②做好工作计划,实施目标管理;③充分发挥门诊部办公室的作用,承上启下,及时协调;④健全门诊管理组织,完善门诊管理规定;⑤抓好服务质量,方便病人就医;⑥加强质量考核,确保门诊工作质量。     

左旋多巴对弱视眼视诱发电位影响的研究

目的:探讨左旋多巴治疗弱视的效果。方法:正常眼和弱视眼服用单次剂量左旋多巴前后进行图形视诱发电位(pattem visual evoked poten-tial,PVEP)检测。结果:正常眼服药后中空间频率PVEP的N_1P_1振幅和高空间频率PVEP的P_1N_2振幅增大,弱视眼服药后低空间频率PVEP的N_1波潜伏期和中空间频率PVEP的P_1波潜伏期缩短。结论:左旋多巴可改善弱视眼的视功能,可作为弱视的一种新的治疗方法。眼科学报1997;13:182—185。     

GABAergic suppression prevents the appearance and subsequent fatigue of an NMDA receptor-mediated potential in neocortex

We have investigated the regulation of anN-methyl-d-aspartate (NMDA) receptor-mediated synaptic potential by γ-aminobutyric acid (GABA)-mediated inhibition using extracellular and whole-cell voltage clamp recordings in rat auditory cortex in vitro. Single afferent stimulus pulses at low intensity elicited a slow extracellular negativity (Component C) that was mediated by NMDA receptors. At higher intensities, Component C was suppressed by recruitment of GABAergic inhibition. To understand the actions of GABAergic inhibition on Component C, we determined the effects of: (i) paired-pulse stimulation, which depresses GABAergic inhibition; (ii) pharmacological antagonism of GABA receptors; and (iii) afferent stimulation in slices from neonatal rats prior to the development of cortical inhibition. The results indicate that GABAergic inhibition prevents Component C fromoccurring, thereby preventing its reduction upon repeated stimulation. Whole-cell voltage clamp recordings were used to test the hypothesis that GABAergic suppression occurred by way of membrane hyperpolarization. At hyperpolarized holding potentials no NMDA receptor-mediated synaptic current was elicited, even with paired-pulse stimulation. At depolarized holding potentials a significant NMDA synaptic current was elicited despite the presence of GABAergic synaptic currents. We conclude that membrane hyperpolarization by GABAergic inhibition prevents the appearance and subsequent fatigue of an NMDA receptor-mediated synaptic potential. Reduction of inhibition can act as a ‘switch’ to fully release the NMDA potential as frequently as once every 10–20 s.     

Auditory event-related magnetic fields in a tone-duration discrimination task. Source localization for the mismatch field and for a new component M2"

Auditory event related magnetic fields were measured using an odd-ball paradigm in which the rare event was a tone of short duration, D2, and the frequent one a tone of longer duration, D1. The subjects were required to attend to and count the number of rare stimuli. In the average across target stimuli a mismatch field (MMF) occurs and the dependence of the MMF, especially its latency, on the tone duration D2 is examined in detail. The location of an equivalent current dipole for the MMF-source is found and turns out to be at variance with earlier results. In addition to the MMF we propose a new component, here called MMF, which in time overlaps the magnetic equivalent of the P200 signal and which has a source location (equivalent current dipole) lying rather close to the MMF-source. The two sources are, however, active at latencies differing by a time equal to D2. We speculate that MMF indicates the onset of the process: "evaluation of tone-duration" while the MMF indicates the end of this process.     

Effect of intravenous ketanserin on the human action potential duration at fixed heart rate

Summary In this study any changes in action potential duration or Q-T interval due to acute doses of ketanserin were monitored. The effect of a bolus dose (10 or 20 mg) followed by an infusion (10 or 20 mg over 20 minutes) of ketanserin on the Q-T interval and action potential duration was studied in six patients undergoing routine cardiac catheterization. Action potential duration was measured with a silver-silver chloride electrode catheter while heart rate was kept constant by atrial pacing and reflex effects avoided by -adrenergic blockade. There were some prolongations of the action potential duration but they were not in excess of 40 msec and did not reach statistical significance (control 263±46.0 msec; bolus 269±52.1 msec; infusion 262±53.6 msec; nor were there any significant changes in Q-T interval. Thus acute intravenous doses of ketanserin, in the absence of hypokalaemia or other Q-T interval-prolonging drugs, have no consistent effect on Q-T interval or action potential duration; prolongation of the action potential, when it occurs, is small.     

Prognostic value of somatosensory- and motor-evoked potentials in patients with a non-traumatic coma

Summary A total of 28 patients with non-traumatic coma were studied both with somatosensory- and motor-evoked potentials. While somatosensory-evoked potentials (SEP) have proved to be useful in predicting the outcome in patients with severe brain damage, the aim of this study was to find out whether the additional evaluation of motor-evoked potentials (MEP) could contribute to a better prediction of the outcome than SEP alone. Our results clearly indicate that in terms of prognostic value, SEP are superior to MEP. Nine patients with bilaterally preserved MEP died, while all of the patients with bilaterally preserved SEP and a central conduction time 6.5 ms survived, with a Glasgow outcome score of 1 to 3. Therefore, we cannot recommend the inclusion of MEP in the prognostic evaluation of patients with non-traumatic coma.