Glutamate acts at NMDA receptors on fresh bovine and on cultured human retinal pigment epithelial cells to trigger release of ATP

Efficient vesicle membrane recycling at presynaptic terminals is pivotal for preventing depletion and maintaining high firing rates in neuronal networks. We used a new approach, based on the combination of spectrally different optical probes, to investigate how stimulation determines the fate of synaptic vesicles after endocytosis. We found that in the small central synapses of rat hippocampal neurones low frequency stimulation (40 action potentials at 2 Hz) targets vesicles preferentially to vesicle pools that were kinetically faster. Vesicles taken up during endocytosis triggered by high frequency stimulation (400 action potentials, 20 Hz) were also placed in the back of the release queue. We performed a spatial analysis of the recycled vesicles in living hippocampal boutons using two spectrally different FM-dyes (FM1-43 and FM5-95). By using these consecutively, vesicles endocytosed by either stimulation protocol were labelled with a different colour. This revealed that the kinetic arrangement was also reflected in the spatial organization of vesicles within the bouton. Next, we identified the postsynaptic site of the active zone by transfecting the neurones with postsynaptic density protein PSD-95-CFP. The data from these triple colour experiments suggest that retrieval after low frequency stimulation keeps vesicles in a more confined region closer to the active zone as identified by PSD-95-CFP expression at the postsynaptic site.     

Nerve growth factor and tyrosine kinase A in human salivary adenoid cystic carcinoma: expression patterns and effects on in vitro invasive behavior.

PURPOSE: Perineural invasion is a frequent occurrence in salivary adenoid cystic carcinoma (ACC) and may prevent complete surgical resection. Studies have indicated that nerve growth factor (NGF) and its high-affinity receptor tyrosine kinase A (TrkA) may play a role in perineural invasion in several malignancies in which perineural invasion is observed. The present study was conducted to investigate the expression of NGF and TrkA in salivary ACC and to examine the effects of NGF on adhesion, migration and invasion capacities of a salivary ACC cell line (SACC-83) in vitro. PATIENTS AND METHODS: Expression of NGF and TrkA was explored using immunohistochemistry in paraffin-embedded tissues of 32 cases of salivary ACC. The effects of NGF on in vitro adhesion, migration, and invasion capacities of the SACC-83 cell line were examined using an MTT assay and a modified Boyden chamber assay respectively. RESULTS: In ACC specimens, 31 (96.9%) and 32 (100%) tumors showed immunoreactivity for NGF and TrkA respectively. Significant correlations were found between NGF/TrkA expression levels and perineural invasion (P < .05). In cell adhesion assay, the percent adherences of SACC-83 cells co-cultured with 25 ng/ml NGF at 1.5 hours and 5, 25 ng/ml NGF at 6 hours were significantly higher than that co-cultured with 0 ng/ml NGF (P < .05). However, high concentration of NGF (500 ng/ml) resulted in a significant inhibition of invasion (P < .05). CONCLUSION: Overexpression of NGF and TrkA in human salivary ACC tissues may constitute a reason for perineural invasion in salivary ACC.     

清胆汤治疗慢性胆囊炎52例

近3年来，笔者自拟清胆汤治疗慢性胆囊炎52例收到较好效果，现报告如下。     

Brain natriuretic peptide enhances the endothelium-independent cAMP and vasorelaxant responses of calcitonin gene-related peptide in rat aorta

Calcitonin gene-related peptide (CGRP) causes vasorelaxation in rat aorta involving endothelium/nitric oxide (NO)-dependent elevations of both cAMP and cGMP levels. When endothelium is removed, preincubation with exogenous NO uncovers and potentiates direct (endothelium-independent) cAMP elevations and vasorelaxations caused by CGRP. This enhancing effect of NO potentially involves elevation of cGMP and inhibition of Type III (cGMPinhibitable) phosphodiesterase, causing accumulation of cAMP. However, NO may have other actions. The aim of the present study was to determine if brain natriuretic peptide (BNP), which elevates cGMP levels independent of NO, could enhance cAMP accumulations and vasorelaxations induced by CGRP in rat aortic rings denuded of endothelium. When added separately, neither CGRP (100 nM) nor BNP (10 nM) altered cAMP levels. When added in combination, CGRP (100 nM) and BNP (10 nM) significantly elevated cAMP levels (from control of 0.95 ± 0.08 to 1.53 ± 0.09 pmol/mg protein) at 2 min. BNP (10 nM) elevated cGMP levels 10-fold at 2 min and this response was not altered by co-administration of CGRP (100 nM).Pretreatment with BNP at concentrations as low as 1 nM in endothelium-denuded aortic rings greatly enhanced the direct vasorelaxant effects of CGRP (100 nM) (from control of 0% to 57.6 ± 6.8% relaxation of phenylephrineprecontractions). Our findings indicate that BNP enhances direct (endothelium-independent) cAMP elevations and vasorelaxations caused by CGRP in rat aorta, thus supporting the concept that cGMP inhibits cAMP metabolism and enhances CGRP-induced responses in aortic smooth muscle cells.     

大鼠脑缺血时脑细胞膜磷脂含量变化

采用SD大鼠一侧大脑中动脉阻断致局限性脑缺血模型。脑缺血后迅速断头置于液氮中,HPLC外标定量法测定各磷脂组分。观察脑缺血1、5、15、60、360min时脑细胞膜磷脂含量变化。结果显示,PI在缺血早期显著低于对照组(P<0.01～0.05);PE、PC早期仅呈下降趋势,PE在缺血60min组、PC缺血360min组显著低于对照组(P<0.01～0.05)。PS在缺血全过程中变化轻微(P>0.05)。提示磷脂降解与脑缺血存在一定关系,缺血早期首先出现脑细胞膜功能磷脂降解,膜结构磷脂则在缺血后期出现显著变化,且PE较PC优先降解。     

酶组化显示睾丸LDH－X方法的再探讨

对小鼠睾丸冰冻切片ＬＤＨ－Ｘ的显示方法作了进一步探讨。实验表明，以Ｌ－２－羟基－３－甲基戊酸（ＨＭＶ）为特异性底物，能相当有效地显示睾丸ＬＤＨ－Ｘ的分布，且该底物的配制方法简便易行。在显示ＬＤＨ－Ｘ的孵育液中采用萘酚蓝（ＮＢ）作中间递电子体较吩嗪甲基硫酸酯更具优越性。     

胫骨延长术后的功能康复程序初探

胫骨延长术是矫治小儿麻痹后遗症下肢短缩最常见的术式，但如何恢复或改善术后的功能，目前尚无一套系统的程序。本文作者根据自行设计的胫骨延长休后功能康复的临床观察，作较系统地介绍，并就该程序的合理性，进行了讨论与论证。     

Chronic opioid treatment of neuroblastoma X dorsal root ganglion neuron hybrid F11 cells results in elevated GM1 ganglioside and cyclic adenosine monophosphate levels and onset of naloxone-evoked decreases in membrane K+ currents

Prolongation of the action potential duration of dorsal root ganglion (DRG) neurons by low (nM) concentrations of opioids occurs through activation of excitatory opioid receptors that are positively coupled via G_s regulatory protein to adenylate cyclase. Previous results suggested GM1 ganglioside to have an essential role in regulating this excitatory response, but not the inhibitory (APD-shortening) response to higher (μM) opioid concentrations. Furthermore, it was proposed that synthesis of GM1 is upregulated by prolonged activation of excitatory opioid receptor functions. To explore this possibility we have utilized cultures of hybrid F11 cells to carry out closely correlated electrophysiological and biochemical analyses of the effects of chronic opioid treatment on a homogeneous population of clonal cells which express many functions characteristic of DRG neurons. We show that chronic opioid exposure of F11 cells does, in fact, result in elevated levels of GM1 as well as cyclic adenosine monophosphate (AMP), concomitant with the onset of opioid excitatory supersensitivity as manifested by naloxone-evoked decreases in voltage-dependent membrane K⁺ currents. Such elevation of GM1 would be expected to enhance the efficacy of excitatory opioid receptor activation of the G_s/adenylate cyclase/cyclic AMP system, thereby providing a positive feedback mechanism that may account for the remarkable supersensitivity of chronic opioid-treated neurons to the excitatory effects of opioid agonists as well as antagonists. These in vitro findings may provide novel insights into the mechanisms underlying naloxone-precipitated withdrawal syndromes and opioid-induced hyperalgesia after chronic opiatf addiction in vivo. © 1995 Wiley-Liss, Inc.     

CT-guided transcutaneous fine-needle aspiration biopsy. A report of 350 cases.

CT-guided transcutaneous fine-needle aspiration biopsies were done in 350 patients. They involved the abdomen in 226 patients (liver 75, pancreatic and abdominal masses 51, kidney 96, adrenal gland 3, spleen 1), thorax 90, musculoskeletal system 32, and brain 2. The accuracy varied with different locations. The accuracy of liver biopsy was 94%, kidney 95.8%, pancreatic and abdominal masses 88.2%, thorax 90%, and musculoskeletal system 96.5%. The occurrence rate of complications was 2.3%. Pneumothorax occurred in 7 patients having thorax biopsy, and gastric perforation in one patient after abdominal biopsy. The proper selection of fine needles, the method and technique, the influential elements of the accuracy, and the application of CT-guided aspiration biopsy were detailed in this paper.

     

铜绿假单胞菌全细胞脂肪酸气相色谱分析及应用

本研究用计算机控制，可程序升温的毛细管柱气相色谱（ＧＣ）仪分析４８株铜绿假单胞菌标准株和临床株、部分常见假单胞菌、肠杆菌的细胞脂肪酸。结果表明：月桂烯酸（Ｃ１２：１），月桂酸（Ｃ１２：０）、十三碳烯酸（Ｃ１３：１）、十三碳酸（Ｃ１３：０）、肉豆劳动脑酸（Ｃ１４：１）、十七碳稀酸（Ｃ１７：１）、十七碳酸（Ｃ１７：０）、硬脂酸（Ｃ１８：０）和花生四烯酸（Ｃ２０：４）是铜绿包菌有鉴别意义的脂肪酸，组成与