An NK1 receptor antagonist affects the circadian regulation of locomotor activity in golden hamsters

Substance P (SP) is a neuromodulator which may participate in the photic regulation of the circadian timing system in mammals. The biological effects of SP are mediated by interaction with specific receptors, designated as NK₁, NK₂, and NK₃. The NK₁ subtype receptor is expressed in the circadian system. Experiment 1 was designed to test whether an NK₁ antagonist mimics the effects of dark pulses. Hamsters were housed in constant lighting conditions, either constant darkness or constant light (around 250 lx), and they received an i.p. injection of either the specific NK₁ receptor antagonist, L-760,735 (5 mg/kg), or saline during the mid-subjective day, a time when dark pulses cause a phase-advance in circadian rhythm of locomotor activity. After treatment with the NK₁ antagonist, significant phase-advances of wheel-running activity rhythm were found in constant light, but not in constant darkness. Experiment 2 was designed to test the ability of the NK₁ antagonist to block the phase-delaying and/or the phase-advancing effects of light in animals kept in constant darkness. Phase-advances of locomotor activity rhythm that can normally be induced by light pulses given during the late subjective night were markedly reduced by pre-treatment with the NK₁ antagonist. By contrast, phase-delays that can be induced by lights pulses given during the early subjective night were unaffected by the NK₁ antagonist. These data support the hypothesis that SP within the circadian system may, by interacting with NK₁ receptors, modulate photic responses of the SCN pacemaker.     

在改进的Ikeda相位重置模型中建立的心搏模式

我们在Ikeda相位重置模型的基础上,考虑异位起搏点（Ectopic Pacemaker,E）的位置及本位起搏点（Sinus Pacemaker,S）对E作用强弱的不同,建立了4个一维分段映象模型,研究心脏在S与E共同驱动下的节律运动。数值计算表明：大部分的心搏模式都是周期性的,在扰动频率和扰动强度的参数平面上具有Arnold舌头分布;异位起搏点位于心室时,有双稳态的动力学模式;在奇重置弱耦合和偶重置异位起搏点的不应期较长时,观察到临床上出现的二联律,三联律等异常心搏模式。     

Demonstration of an Excitable Gap in the Common Form of Atrioventricular Nodal Reentrant Tachycardia

Premature ventricular depolarizations were introduced during sustained atrioventricular nodal reentrant tachycardia ("slow-fast" type) in a single patient during electrophysiological study. Preexcitation of the atrium with retrograde His bundle capture occurred over an 85 msec range of coupling intervals between the last antegmde His bundle depolarization and the first retrograde His bundle depolarimtion associated luith the premature beat (H₁ - H₂ interval). The interval between the retrograde His bundle depolarization (H₂) and the retrograde atrial depolarization (A₂) remained constant over this 85 msec excitable gap as the H₁-H₂ interval decreased. This indicates the presence of fully excitable tissue luithin the retrograde fast pathway of the reentrant circuit during the tachycardia and demonstrates the utility of this technique for defining the extent and conduction properties of the excitable gap in reentrant arrhythmias     

The effects of lesions in the dorsolateral pons on the coordination of swallowing and breathing in awake goats

The purpose of this retrospective study was to gain insight into the contribution of the dorsolateral pons to the coordination of swallowing and breathing in awake goats. In 4 goats, cannulas were chronically implanted bilaterally through the lateral (LPBN) and medial (MPBN) parabrachial nuclei just dorsal to the Kölliker–Fuse nucleus (KFN). After >2 weeks recovery from this surgery, the goats were studied for 5½ h on a control day, and on separate days after receiving 1 and 10 μl injections of ibotenic acid (IA) separated by 1 week. The frequency of swallows did not change during the control and 1 μl IA studies, but after injection of 10 μl IA, there was a transient 65% increase in frequency of swallows (P < 0.05). Under control conditions swallows occurred throughout the respiratory cycle, where late-E swallows accounted for 67.6% of swallows. The distribution of swallow occurrence throughout the respiratory cycle was unaffected by IA injections. Consistent with the concept that swallowing is dominant over breathing, we found that swallows increased inspiratory (T_I) and expiratory (T_E) time and decreased tidal volume (V_T) of the breath of the swallow (n) and/or the subsequent (n + 1) breath. Injections of 10 μl IA attenuated the normal increases in T_I and T_E and further attenuated V_T of the n breath. Additionally, E and I swallows reset respiratory rhythm, but injection of 1 or 10 μl IA progressively attenuated this resetting, suggesting a decreased dominance over respiratory motor output with increasing IA injections. Post mortem histological analysis revealed about 50% fewer (P < 0.05) neurons remained in the KFN, LPBN, and MPBN in lesioned compared to control goats. We conclude that dorsolateral pontine nuclei have a modulatory role in a hypothesized holarchical neural network regulating swallowing and breathing particularly contributing to the normal dominance of swallowing over breathing in both rhythm and motor pattern generation.     

Stroke volume decreases during mild dynamic and static exercise in supine humans

Aim: The contributions of cardiac output (CO) and total peripheral resistance to changes in arterial blood pressure are debated and differ between dynamic and static exercise. We studied the role stroke volume (SV) has in mild supine exercise. Methods: We investigated 10 healthy, supine volunteers by continuous measurement of heart rate (HR), mean arterial blood pressure, SV (ultrasound Doppler) and femoral beat volume (ultrasound Doppler) during both dynamic mild leg exercise and static forearm exercise. This made it possible to study CO, femoral flow (FF) and both total and femoral peripheral resistance beat‐by‐beat. Results: During a countdown period immediately prior to exercise, HR and mean arterial pressure increased, while SV decreased. During mild supine exercise, SV decreased by 5–8%, and most of this was explained by increased mean arterial pressure. Dynamic leg exercise doubled femoral beat volume, while static hand grip decreased femoral beat volume by 18%. FF is tightly regulated according to metabolic demand during both dynamic leg exercise and static forearm exercise. Conclusion: Our three major findings are, firstly, that SV decreases during both dynamic and static mild supine exercise due to an increase in mean arterial pressure. Secondly, femoral beat volume decreases during static hand grip, but FF is unchanged due to the increase in HR. Finally, anticipatory responses to exercise are apparent prior to both dynamic and static exercise. SV changes contribute to CO changes and should be included in studies of central haemodynamics during exercise.     

卵巢肿瘤蒂扭转复位手术12例分析

目的探讨卵巢肿瘤蒂扭转复位手术的可行性。方法对12例卵巢肿瘤蒂扭转者进行复位手术，术前超声检查了解扭转蒂之血流情况，术中对卵巢缺氧较重者进行湿热敷，血运改善后进行肿瘤剔除，快速病理检查．排除恶性肿瘤后行卵巢修复。术后1至3个月时，进行超声和内分泌检查，并与术前进行比较。结果12例卵巢肿瘤蒂扭转复位手术均成功，病理结果显示均为良性，无血栓及栓塞发生，无严重并发症。卵巢功能短期内恢复。结论卵巢肿瘤蒂扭转复位手术是安全可行的。应进一步规范其适应证。     

房室结折返性心动过速的可激动间隙及分区

目的探讨典型的房室结双径路引起的房室结折返性心动过速(AVNRT)可激动间隙的特点及其分区。方法25例AVNRT患者心动过速发作后,分别在右室心尖部和高位右房给予VS2和AS2早搏刺激,从心动过速周长-10ms开始刺激,相隔8个心动过速周期,以-10ms的步长进行递减扫描,测定可激动间隙,并与41例房室折返性心动过速(AVRT)患者比较。结果25例AVNRT患者中,2例经右心房AS2刺激可以使心动过速重整,仅2例患者可经心房AS2刺激使心动过速终止,3例经心室VS2刺激可以使心动过速重整,经心室VS2刺激均未能使心动过速终止,与AVRT患者比较有显著性差异(P<0.05)。心动过速重整时,偶联间期与回归间期之和可小于心动过速周长的2倍,亦可等于心动过速周长的2倍。结论刺激部位不同,折返环不同,所暴露的可激动间隙可能不同。刺激的偶联间期与回归间期之和等于心动过速周长的2倍,不能排除心动过速的重整。     

Locating ectopic foci

INTRODUCTION: Successful radiofrequency ablation of an ectopic focus requires accurate localization of the region of enhanced automaticity. Present localization techniques require detailed electrical mapping that is time-consuming and involves much trial and error. Here, we propose two new localization techniques which were used to locate a pacemaker in a computer simulation. METHODS AND RESULTS: We suggest that an ectopic focus can be located by measuring the activation sequence of three or more intracardiac electrodes subsequent to an ectopic depolarization. Furthermore, the resetting response of an ectopic pacemaker can be used to estimate the distance from the stimulation electrode to the ectopic focus. We derive simple geometric localization strategies based on these ideas and examine the sensitivity of the strategies with respect to measurement uncertainties and electrode arrangements. Our localization strategies were tested using a numerical simulation of a pacemaker in a sheet of excitable media described by modified FitzHugh-Nagumo equations. The strategy based on electrode activation sequences located the pacemaker region in a homogeneous isotropic sheet after an average of 2.2 +/- 0.8 iterates in 10 out of 10 trials starting from random initial catheter positions. In the case of an inhomogeneous anisotropic sheet, the pacemaker was located after an average of 4 +/- 3 iterates in 9 out of 10 trials. The localization strategy based on resetting successfully found the pacemaker in a homogeneous isotropic sheet after an average of 1.2 +/- 0.4 iterates in 5 out of 5 trials and localized the pacemaker in an inhomogeneous anisotropic sheet after an average of 1.4 +/- 0.5 iterates in 5 out of 5 trials. CONCLUSIONS: Simple geometric strategies can be used to locate an ectopic focus. Although our basic localization strategies are sensitive to the electrode arrangement and measurement uncertainties, we show that iteration of our techniques quickly locates the pacemaker.     

定点旋转复位法治疗腰椎间盘突出症临床报告

随着社会的发展,工作种类的增多,工作压力的不断增加,常常忽视了身体的锻炼,在工作时常常感到腰痛,其中腰椎间盘突出症（LIDP）为临床常见病,多发病,复发率高,严重影响患者的工作和生活。目前治疗LIDP分手术和非手术治疗,非手术治疗是治疗本病的基本方法,约有80％～90％的患者经过非手术方法治疗可收到良好的效果,只有不到10％的LIDP患者需要手术治疗。传统的牵引,推拿,针灸,理疗等方法存在治疗时间长,疗效差,易复发等弊端。我院在2003年引进定点旋转复住法后应用于临床的疗效报告如下。