Inter- and Intra-Subject Variability of Neuromagnetic Resting State Networks

Functional connectivity studies conducted at the group level using magnetoencephalography (MEG) suggest that resting state networks (RSNs) emerge from the large-scale envelope correlation structure within spontaneous oscillatory brain activity. However, little is known about the consistency of MEG RSNs at the individual level. This paper investigates the inter- and intra-subject variability of three MEG RSNs (sensorimotor, auditory and visual) using seed-based source space envelope correlation analysis applied to 5 min of resting state MEG data acquired from a 306-channel whole-scalp neuromagnetometer (Elekta Oy, Helsinki, Finland) and source projected with minimum norm estimation. The main finding is that these three MEG RSNs exhibit substantial variability at the single-subject level across and within individuals, which depends on the RSN type, but can be reduced after averaging over subjects or sessions. Over- and under-estimations of true RSNs variability are respectively obtained using template seeds, which are potentially mislocated due to inter-subject variations, and a seed optimization method minimizing variability. In particular, bounds on the minimal number of subjects or sessions required to obtain highly consistent between- or within-subject averages of MEG RSNs are derived. Furthermore, MEG RSN topography positively correlates with their mean connectivity at the inter-subject level. These results indicate that MEG RSNs associated with primary cortices can be robustly extracted from seed-based envelope correlation and adequate averaging. MEG thus appears to be a valid technique to compare RSNs across subjects or conditions, at least when using the current methods.     

釉基质蛋白对人牙髓细胞成牙本质分化的影响

目的 探讨釉基质蛋白对人牙髓细胞(human dental pulp cells,HDPC)成牙本质分化的影响,为牙本质的组织工程学研究提供有效的生物活性物质.方法 将HDPC接种于6孔板(2×105个/孔)后分为5组,分别加入含1、10、100 mg/L釉基质蛋白(enamel matrix proteins,EMP)(分别为EMP 1、10、100 mg/L组)、10-8 mol/L地塞米松及100 mg/L抗坏血酸(dexamethasone and ascorbic acid,Dex-AA组)、单纯基础培养液(对照组).于培养1、5、10 d分别用碱性磷酸酶(alkaline phosphatase,ALP)试剂盒检测ALP活性,实时荧光定量反转录聚合酶链反应技术检测成牙本质相关基因牙本质基质蛋白1(dentine matrix protein-1,DMP-1)及牙本质涎磷蛋白(dentine sialophosphoprotein,DSPP)的表达,应用2-△△CT方法得出具体数值并进行单因素方差分析与Post Hoe 检验,用茜素红染色检测并定量分析矿化情况.结果 各组ALP水平呈时间依赖性上调,培养1d后各组ALP活性与对照组相比差异均无统计学意义;5 d后EMP 10、100 mg/L组及Dex-AA组ALP活性显著增高,分别达到7.573±0.267、6.119±0.502、5.846±0.096,与对照组相比差异均有统计学意义(P＜0.05);10 d后10 mg/L EMP组及Dex-AA组ALP活性增高更显著,分别达21.035±0.149、13.223±0.797,与对照组(5.825±0.404)相比差异均有统计学意义(P＜0.01).培养1d后各组DMP-1及DSPP mRNA水平均较对照组显著升高,差异均有统计学意义(P＜0.01);培养10 d后10 mg/L EMP组DMP-1和DSPP表达水平均显著增高,分别达到14.791±0.164、12.238±0.421.培养10 d后各组均有矿化,10 mg/L EMP组钙离子浓度[(191.8±2.0) μmol/L]显著高于对照组[(81.1±8.1)μmol/L],差异有统计学意义(P＜0.01).结论 适当浓度的EMP对HDPC的成牙本质分化有一定的促进作用.     

Single incision laparoscopic adjustable gastric band: technique,feasibility, safety and learning curve

Introduction

Single incision laparoscopic surgery (SILS) is established in many procedures but not in bariatric surgery. One explanation may be that SILS is technically demanding in morbidly obese patients. This report describes our technique and experience with single incision laparoscopic adjustable gastric banding (SILAGB).

Methods

Prospective data collection was performed on consecutive obese patients who underwent SILAGB between November 2009 and February 2011. A single 3cm transverse incision in the right upper quadrant was used for a Covidien SILS^™ multichannel access port. The technique is described with a standard pars flaccida approach and the ‘tips and tricks’ needed for a wide range of candidates using standard laparoscopic equipment.

Results

A total of 29 patients (27 female) with a median body mass index of 41kg/m² (range: 35–52kg/m²) and median age of 44 years (range: 22–57 years) underwent SILAGB. There were no ‘conversions’ to a standard laparoscopic technique. Two cases required the addition of one single 5mm port. The only complications were two postoperative wound infections (one with a port site infection requiring replacement of the port) and one faulty band requiring replacement. There were therefore two returns to theatre and no 30-day deaths. All patients were discharged on the first postoperative day. In this series, operative times reduced significantly to be comparable with the conventional laparoscopic approach.

Conclusions

SILAGB is safe and feasible in the morbidly obese. Proficiency in this technique using conventional laparoscopic equipment can be achieved with a short learning curve.