脑缺血再灌注损伤后RGMb表达的变化及其对轴突生长的作用

目的探讨大鼠脑缺血再灌注损伤后RGMb(repulsive guidance molecule b)表达的变化及RGMb在体外对轴突生长的作用。方法①取出生后7-9d的Wistar大鼠提取内嗅皮层(entorhinal cortex,EC)细胞,分为:正常对照组和RGMb(10μg/ml)处理组,采用细胞培养和免疫荧光染色等方法,检测在体外培养中RGMb处理的新生大鼠EC细胞轴突长度的变化。②取正常8w的Wistar大鼠10只,随机分为:假手术组和脑缺血再灌注48h组,各5只。采用Western blot方法检测脑缺血再灌注48h后海马组织中RGMb表达的变化。结果①在体外培养中RGMb(10μg/ml)能抑制新生大鼠EC细胞轴突的生长。②脑缺血再灌注48h后成年大鼠海马组织中RGMb的表达明显上调。结论脑缺血再灌注损伤后RGMb表达明显增加,提示RGMb可能参与脑缺血再灌注损伤后的神经再生障碍、炎症和细胞凋亡等病理生理过程。     

“Reverse” Bypass Using a Naturally Formed “Bonnet” Superficial Temporal Artery in Symptomatic Common Carotid Artery Occlusion: A Case Report

We herein describe a patient with symptomatic common carotid artery occlusion who underwent a reverse superficial temporal artery (STA)-middle cerebral artery (MCA) single bypass using a naturally formed “bonnet” STA. The surgical procedure was performed without difficulty, and no further neurological deterioration was observed after surgery. In practice, this case highlights that the reverse STA-MCA bypass can be achieved safely and less invasively using a naturally formed “bonnet” STA.     

Preservation of the Long Insular Artery to Prevent Postoperative Motor Deficits after Resection of Insulo-opercular Glioma: Technical Case Reports

Resection of insulo-opercular gliomas carries the risk of postoperative hemiparesis caused by ischemia of the corona radiata resulting from injury to the long insular arteries. However, intraoperative identification of these perforating arteries is challenging. We attempted intra-operative motor evoked potential (MEP) monitoring under temporary occlusion of the suspected long insular artery arising from the opercular portion of middle cerebral artery in two patients with insulo-opercular gliomas. Temporary occlusion of the artery caused decrease in MEP amplitude, which recovered after release in one patient, who had no postoperative motor deficits or ischemic lesion in the corona radiata. Temporary occlusion of the artery caused no changes in MEP amplitude, so that the artery was sacrificed for tumor removal in the other patient, who had no motor deficits but ischemic lesion was present in the corona radiata in the territory of the long insular artery sparing the descending motor pathway. These cases show that great care should be taken during surgical manipulations near the posterior part of the superior limiting sulcus to preserve the perforating branches to the corona radiata, and temporary occlusion of the branches under MEP monitoring is useful to identify the arteries supplying the pyramidal tract.     

Sinus node recovery function is relatively well preserved under halothane anaesthesia in children

The purpose of this study was to evaluate the effect of halothane on sinus node recovery time (SNRT). Nine children with congenital heart disease scheduled for cardiac catheterization were studied. After the routine procedure, the sinus node was paced at rates of 120, 150 and 180 beats per minute. SNRTs were measured with control conditions and under 1 MAC halothane anaesthesia. The absolute SNRT was standardized and expressed as ‘%SNRT’ and ‘Corrected SNRT (CSNRT)’. CSNRT was slightly prolonged by halothane (P= 0.042), while the %SNRT was not significantly prolonged. We conclude that the recovery function of the sinus node is relatively well preserved under 1 MAC halothane in children.     

T-Independent Polyclonal Activation of B Cells In Vitro by Immunoglobulin Binding Substance (IBS) from the Granary Weevil

Experiments are described for T-independent polyclonal activation of B cells in vitro by the immunoglobulin binding substance (IBS) from the granary weevil. The affinity-chromatographically purified IBS was used. IBS is a heat-, alkali- and acid-stable glucopeptide which is characterized by non-specific immunoglobulin binding to the Fab fragment. The purified IBS consists of three polymer homologues whose molecular weights are 12-14,000, 25-30,000 and more than 150,000 Da. IBS did not stimulate DNA synthesis by murine T cells, macrophages or plasma cells whereas it did stimulate that by mature B cells without any help from T cells or macrophages. IBS also stimulated both in vitro IgG production by spleen cells and in vitro sensitization of spleen cells by sheep red cells (SRBC). IBS was found to stimulate DNA synthesis by B cells mediated by binding to surface immunoglobulins of B cells. IBS is thought to be a useful amplifier for inducing human hybridomas and a valuable tool for examining mature B cells, both diagnostically and experimentally.     

High-density lipoproteins from probucol-treated patients have increased capacity to promote cholesterol efflux from mouse peritoneal macrophages loaded with acetylated low-density lipoproteins

To elucidate the anti-atherogenic effect of probucol, high-density lipoprotein (HDL) was isolated from probucol-treated patients (n = 14) and compared with that from control subjects (n = 12). The HDL obtained from probucol-treated patients was low in cholesteryl ester (CE) in comparison with that from control subjects (21.3 ± 3.9 mol per cent vs. 27.6 ± 3.2 mol% of total lipids, P < 0.001), and the peak diameters of patients' HDL were significantly smaller than those of control subjects on 4–30% non-denaturing polyacrylamide gradient gel electrophoresis (10.6 ± 0.6 nm vs. 12.1 ± 0.4 nm, P < 0.001). These data may be explained by the increased cholesteryl ester transfer protein (CETP) activities of probucol-treated patients (129 ± 12% of control subjects, P < 0.001). The in vitro ability of HDL to remove CE from lipid-laden macrophages induced by incubation with acetylated low-density lipoprotein (Ac-LDL) was studied. The small and CE-poor HDL obtained from probucol-treated patients had a greater capacity to promote CE efflux from macrophages than did control HDL (59.8 ± 6.9% vs. 44.2 ± 5.4%, P < 0.01). Furthermore, the ability of HDL to promote cholesterol efflux correlated negatively with the CE content and particle diameter of HDL (r = ?0.561 and r = ?0.583 respectively; P < 0.01). When the inhibitory effect of HDL on the incorporation of [¹⁴C]-oleate into cellular cholesteryl ester was compared, the HDL from patients and control subjects inhibited CE formation to a similar extent. The enhanced ability of probucol-treated patients' HDL may, therefore, be involved in the acceleration of hydrolysis of the CE pool in macrophages. Taken together, we conclude that CETP plays a crucial role in making HDL more active in its anti-atherogenic function by reducing CE and making HDL smaller, and that probucol may enhance reverse cholesterol transport by activating CE transfer in vivo. The current study demonstrated, for the first time, that HDL modified by enhanced CETP activity in vivo is potentially anti-atherogenic.     

Site of the Arrhythmogenic Focus and Cardiac Vulnerability to Ventricular Fibrillation

MURAKAWA, Y., et al. : Site of the Arrhythmogenic Focus and Cardiac Vulnerability to Ventricular Fib-rillation. The aim of this study was to test the hypothesis that a subendocardial arrhythmogenic focus makes the heart more susceptible to VF due to electrical interaction with the Purkinje network. Monofocal ventricular tachycardia (mVT) was created by injecting 5-μg aconitine into the left ventricular subepicardium (  EPI-mVT, n = 8  ) or subendocardium (  ENDO-mVT, n = 13  ) in anesthetized dogs. Despite the similar cycle length of mVT, the incidence of VF was significantly different between EPI-mVT and ENDO-mVT (  100 [8/8] vs 46% [6/13], P < 0.05  ). VF was invariably preceded by hemodynamic deterioration. Three-dimensional cardiac mapping (  n = 10, 221 ± 11 recording sites  ) revealed that VF was triggered solely by focal firing unrelated to the primary arrhythmogenic focus in both mVT models. No interaction between the primary focus and adjacent endocardial tissue was indicated. These results suggest that the proximity of the arrhythmogenic focus to the Purkinje network has little role in cardiac vulnerability to VF, and that progression of mVT to VF is largely caused by sporadic focal firing regardless of the site of the arrhythmogenic focus in the present animal model.     

Assessing the clinical utility of the magnetic stimulator for measuring response latencies in the laryngeal muscles

Our purpose was to assess the use of magnetic stimulation for measuring conduction time of the recurrent and superior laryngeal nerves in 10 normal volunteers (7 male, 3 female). Subjects underwent laryngeal electromyography and magnetic stimulation of the vagus nerve bilaterally at the mastoid tip with a figure 8 coil. Mean muscle response latencies were measured and examined for consistent differences. Thyroarytenoid muscle response latencies were consistently longer than those in the cricothyroid muscle. Left thyroarytenoid muscle latencies were consistently longer than those on the right in agreement with bilateral asymmetry of these nerves. No appreciable differences were observed in cricothyroid muscle latencies when the right side was compared with the left. Results were consistent and reproducible within a broad range, but appreciable intersubject variability was observed. The limited sample size was unable to support a correlation with anthropometric variables, although an association was indicated. Magnetic stimulation with this technique has great potential for use in neurolaryngologic studies. (Otolaryngol Head Neck Surg 1996;114:761-7.)