神经刺激仪经肌间沟定位臂丛神经分支行臂丛麻醉效果分析

目的：比较神经刺激仪经肌间沟定位臂丛神经分支行肌间沟臂丛神经阻滞麻醉的效果及安全性。方法：选择拟行肌间沟臂丛神经阻滞的上肢手术的患者80例,ASAI或II级,随机均分为A组和B组,每组40例患者。两组均给予1％的利多卡因＋0．375％耐乐品20mL。记录完成操作所需时间、感觉神经阻滞起效时间、感觉神经阻滞完善时间、运动神经阻滞起效时间、运动神经阻滞完善时间;评价手术区域麻醉效果（优、良、差、失败）;观察并记录并发症。结果：A组完成操作所需时间（5．01±1．40）min,明显长于B组（2．83＋O．87）min（P〈0．01）。A组感觉阻滞起效时间（4．48±1．36）min,明显短于B组（7．0±2．06）min（P〈0．01）;A组运动阻滞起效时间（4．88＋±1．18）min,明显短于B组（7．0±1．67）min（P〈0．01）。A组感觉阻滞完善时间（11．73±3．62）短于B组（13．33±3．02）min（P=0．033）。A组运动阻滞完善时间（11．18±2．73）短于B组（12．41±2．48）min（P=0．038）;麻醉效果优等率A组为87．5％,B组为67．5％,差异有统计学意义x^2=4．588,P=0．032;优良率A组为97．5％,B组为90．0％,差异无统计学意义x2=1．920,P=0．166;A组、B组均未出现严重麻醉并发症。结论：A组行肌间沟臂丛神经阻滞比B组阻滞操作时间长,但神经阻滞麻醉效果好,神经阻滞完善率高。     

Generation of an ABCG2 transgenic line - A tool to study ABCG2 expression in mice

The ATP-binding cassette (ABC) transporter 2 (ABCG2) is expressed by stem cells in many organs and in stem cells of solid tumors. These cells are isolated based on the side population (SP) phenotype, a Hoechst 3342 dye efflux property believed to be conferred by ABCG2. Because of the limitations of this approach we generated transgenic mice that express Nuclear GFP (GFPn) coupled to the Puromycin-resistance gene, under the control of ABCG2 promoter/enhancer sequences. We show that ABCG2 is expressed in neural progenitors of the developing forebrain and spinal cord and in embryonic and adult endothelial cells of the brain. Using the neurosphere assay, we isolated tripotent ABCG2-expressing neural stem cells from embryonic mouse brain. This transgenic line is a powerful tool for studying the expression of ABCG2 in many tissues and for performing functional studies in different experimental settings.     

Toxoplasma gondii: myenteric neurons of intraperitoneally inoculated rats show quantitative and morphometric alterations

Several studies have demonstrated that the myenteric plexus experiences quantitative and morphometric changes in rats inoculated orally with Toxoplasma gondii. This paper aims to verify if these alterations are also seen when the same animals are inoculated intraperitoneally with the parasite. In order to do that, six Wistar rats (Rattus norvegicus) 60 days of age were infected intraperitoneally with 10⁶ tachyzoites of a genotype I T. gondii strain (BTU IV). After 60 days, the animals were anaesthetised and underwent laparotomy. All organs from the small and large intestines were removed, measured, dissected and underwent whole-mount Giemsa technique to stain the neurons in the myenteric plexus. A quantitative and morphometric analysis of these cells was made, and it showed that the parasite causes the death of myenteric neurons in the jejunum and morphometric alterations in these cells throughout the intestine. However, the cellular response of myenteric neurons to T. gondii is heterogeneous compared the different organs from the gut.     

24S-hydroxycholesterol induces cholesterol release from choroid plexus epithelial cells in an apical- and apoE isoform-dependent manner concomitantly with the induction of ABCA1 and ABCG1 expression

The release of cholesterol from choroid plexus epithelial cells (CPE) plays an important role in cholesterol homeostasis in the CSF. The purpose of this study was to clarify the molecules involved in cholesterol release in CPE and the regulation mechanisms of the cholesterol release by the liver X receptor (LXR) using a conditionally immortalized CPE line (TR-CSFB3). The mRNA expression of LXRalpha, LXRbeta and their target genes, ATP-binding cassette transporter (ABC)A1, ABCG1, ABCG4 and ABCG5, were detected in rat choroid plexus. ABCA1 and ABCG1 protein were detected in the plasma membrane of TR-CSFB3 cells. Following treatment with 24S-hydroxycholesterol, an endogenous LXR ligand, the expression of ABCA1 and ABCG1 were induced in TR-CSFB3 cells. Moreover, apolipoprotein (apo)AI- and high-density lipoprotein (HDL)-mediated cholesterol release to the apical side of TR-CSFB3 cells was facilitated by this treatment, whereas that to the basal side was not affected. Following 24S-hydroxycholesterol treatment, apoE3-dependent cholesterol release from TR-CSFB3 cells was enhanced more than the apoE4-dependent release. These results suggest that LXR activation facilitates cholesterol release into the CSF from CPE through the functional induction of ABCA1 and ABCG1. The difference between apoE3 and apoE4 suggests that the cholesterol release from CPE is related to the development of neurodegenerative diseases.     

Colocalization of NO and VIP in neurons of the submucous plexus in the rat intestine

Since very few previous studies have carried out the quantitative analysis for the colocalization of nitric oxide (NO) and vasoactive intestinal peptide (VIP) in the submucous neurons in the rat digestive tract, we applied in vivo treatment of colchicine to enhance the immunoreactivity and examined the colocalization of NO synthase (nNOS) and VIP in neurons of the submucous plexus throughout the rat digestive tract. The density of nNOS-containing neurons in the submucous plexus in the stomach corpus (103±25 cells/cm², n=3) and that in the antrum (157±9 cells/cm², n=3) were significantly lower than those in small and large intestine. However no difference was detected in the cell density among duodenum (1967±188 cells/cm², n=3), jejunum (2640±140 cells/cm², n=3), ileum (2070±42 cells/cm², n=3), proximal colon (2243±138 cells/cm², n=3) and distal colon (2633±376 cells/cm², n=3). The proportion of nNOS-immunoreactive (IR), nNOS/VIP-IR and VIP-IR neurons to the total number of submucous neurons was examined. nNOS/VIP-IR neurons comprised 45–55% of total number of submucous neurons from the duodenum to the proximal colon, however those comprised 66.4±5.1% in the distal colon. The results showed that the dense distribution of nNOS-containing neurons was found in the submucous plexus throughout the small and large intestine, and large population of submucous neurons co-stored nNOS and VIP.     

Sonic hedgehog is required for vascular outgrowth in the hindbrain choroid plexus

Critical to the exchange and metabolic functions served by tissues like brain choroid plexi and lung is the coherent development of an epithelial sheet of large surface area in tight apposition to an extensive vascular bed. Here, we present functional experiments in the mouse demonstrating that Sonic hedgehog (Shh) produced by hindbrain choroid plexus epithelium induces the extensive vascular outgrowths and vascular surface area fundamental to choroid plexus functions, but does not induce the more specialized endothelial cell features of fenestrations and bore size. Our findings indicate that these Shh-dependent vascular elaborations occur even in the presence of Vegf and other established angiogenic factors, suggesting either that the levels of these factors are inadequate in the absence of Shh or that a different set of factors may be more essential to choroid plexus outgrowth. Transducing the Shh signal is a perivascular cell—the pericyte—rather than the more integral vascular endothelial cell itself. Moreover, our findings suggest that hindbrain choroid plexus endothelial cells, as compared to other vascular endothelial cells, are more dependent upon pericytes for instruction. Thus, in addition to Shh acting on the progenitor pool for choroid plexus epithelial cells, as previously shown, it also acts on choroid plexus pericytes, and together serves the important role of coordinating the development of two disparate yet functionally dependent structures—the choroid plexus vasculature and its ensheathing epithelium.     

Repurposing of the multiciliation gene regulatory network in fate specification of Cajal-Retzius neurons

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Separation of Recycling and Reserve Synaptic Vesicles from Cholinergic Nerve Terminals of the Myenteric Plexus of Guinea Pig Ileum

Acetylcholine-rich synaptic vesicles were isolated from myenteric plexus-longitudinal muscle strips derived from the guinea pig ileum by the method of Dowe, Kilbinger, and Whittaker [J. Neurochem. 35, 993-1003 (1980)] using either unstimulated preparations or preparations field-stimulated at 1 Hz for 10 min using pulses of 1 ms duration and 10 V . cm-1 intensity. The organ bath contained either tetradeuterated (d4) choline (50 microM) or [3H]acetate (2 muCi . ml-1); d4 acetylcholine was measured by gas chromatography-mass spectrometry. As with Torpedo electromotor cholinergic vesicle preparations made under similar conditions the distribution of newly synthesized (d4 or [3H]) acetylcholine in the zonal gradient from stimulated preparations was not identical with that of endogenous (d0, [1H]) acetylcholine, but corresponded to a subpopulation of denser vesicles (equivalent to the VP2 fraction from Torpedo) that had preferentially taken up newly synthesized transmitter. The density difference between the reserve (VP1) and recycling (VP2) vesicles was less than that observed in Torpedo but this smaller difference can be accounted for theoretically by the difference in size between the vesicles of the two tissues. At rest, a lesser incorporation of labelled acetylcholine into the vesicle fraction was observed, and the peaks of endogenous and newly synthesized acetylcholine coincided. Stimulation in the absence of label followed by addition of label did not lead to incorporation of labelled acetylcholine, suggesting that the synthesis and storage of acetylcholine in this preparation and its recovery from stimulation is much more rapid than in Torpedo.     

Ca2+-activated K+ channels in the apical membrane ofNecturus choroid plexus

Summary The properties of Ca²⁺-activated K⁺ channels in the apical membrane of theNecturus choroid plexus were studied using single-channel recording techniques in the cell-attached and excised-patch configurations. Channels with large unitary conductances clustered around 150 and 220 pS were most commonly observed. These channels exhibited a high selectivity for K⁺ over Na⁺ and K⁺ over Cs⁺. They were blocked by high cytoplasmic Na⁺ concentrations (110mm). Channel activity increased with depolarizing membrane potentials, and with increasing cytoplasmic Ca²⁺ concentrations. Increasing Ca²⁺ from 5 to 500nm, increased open probability by an order of magnitude, without changing single-channel conductance. Open probability increased up to 10-fold with a 20-mV depolarization when Ca²⁺ was 500nm. Lowering intracellular pH one unit, decreased open probability by more than two orders of magnitude, but pH did not affect single-channel conductance. Cytoplasmic Ba²⁺ reduced both channel-open probability and conductance. The sites for the action of Ba²⁺ are located at a distance more than halfway through the applied electric field from the inside of the membrane. Values of 0.013 and 117mm were calculated as the apparent Ba²⁺ dissociation constants (K _d (0 mV) for the effects on probability and conductance, respectively. TEA⁺ (tetraethylammonium) reduced single-channel current. Applied to the cytoplasmic side, it acted on a site 20% of the distance through the membrane, with aK _d (0 mV)=5.6mm. A second site, with a higher affinity,K _d (0 mV)=0.23mm, may account for the near total block of chanel conductance by 2mm TEA⁺ applied to the outside of the membrane. It is concluded that the channels inNecturus choroid plexus exhibit many of the properties of maxi Ca²⁺-activated K⁺ channels found in other tissues.