Functional imaging and localization of electromagnetic brain activity

Functional imaging of electric brain activity requires specific models to transform the signals recorded at the surface of the human head into an image. Two categories of model are available: single-time-point and spatio-temporal methods. The instantaneous methods rely only on the few voltage differences measured at one sampling point. To create a spatial image from this limited information, they require strict assumptions that rarely conform with the underlying physiology. Spatio-temporal models create two kinds of images: first, a spatial image of discrete equivalent multiple dipoles or regional sources, and second, an image of source current waveforms that reflect the temporal dynamics of the brain activity in circumscribed areas. The accuracy of the spatial image is model dependent and limited, but it can be validated from the spatio-temporal data by the "regional source imaging" technique, introduced here. The source waveforms are linear combinations of the scalp waveforms, and thus, specific derivations which image local brain activities at a macroscopic level. Brain source imaging of somatosensory evoked potentials revealed temporally overlapping activities from the brainstem, thalamus and from multiple sources in the region of the contralateral somatosensory projection areas.     

术中超声引导切除不可触及的乳腺病变

应用术中超声引导技术切除 65例女性患者 83处不可触及的乳腺病变 (nonpalpablebreastlesions ,NPBL) ,并对切除新鲜标本超声扫描确定NPBL是否已切除。 48处采用放射状切口 ,3 5处采用乳晕旁切口。切除标本最大直径10～ 3 0mm (平均 17 5mm) ,标本NPBL最大直径 5～ 17mm (平均 10 7mm) ,超声NPBL最大直径 6～ 19mm (平均11 9mm) ,NPBL的超声最大直径与标本最大直径呈高度一致 ,P <0 0 0 1。 83处NPBL首次切除标本中 ,4处超声未探及病灶 ,立即再切除获得成功。病理检查 :良性 78处 ,分别为 61处纤维腺瘤 ,5处管内乳头状瘤 ,12处纤维囊性乳腺病 ;恶性 5处 ,其中 2处为病理早期癌。恶性 5例追加改良根治术乳房标本无癌组织残留。良性患者术后 3～ 10个月随访 ,乳晕旁切口较放射状切口瘢痕更轻微 ,超声未发现复发病灶。初步研究的结果提示 ,术中超声引导切除NPBL是一种准确可行的手术方法 ,可以发现早期乳腺癌     

CT引导下带钩钢丝术前定位在胸腔镜下孤立性肺小结节切除术中的应用

Objective Video-assisted thoracoscopic surgery (VATS) provides a minimally invasive approach to resect small solitary pulmonary nodules (SSPN). The aim of this study is to evaluate the efficacy and safety of preoperative CT-guided hookwire localization for SSPN in VATS. Methods Hookwire was used to localize 26 SSPN under CT guidance in 24 patients (14 male, 10 female, age range 21-61 years, mean 52.3 years), preoperatively, and wedge resection was performed through VATS. The lesion size, distance from the lesion to parietal pleura, the time of localization and complications were evaluated. Results All the 26 pulmonary nodules were preoperatively detected and localized with hookwire under CT-guidance. The mean lesion size was 10.05 ± 3.08 nun in diameter, and the mean distance from lesion to parietal pleura was 10.09±2. 62 mm. The mean localization time was 20. 18±7.16 min, and then the nodules were removed by VATS within 18 ± 6. 65 min. The major complication of CT-guided hookwire localization was mild pneumothorax in 6 patients (25.0%), but no one needed chest tube drainage. The dislodgment of hookwire was found in only one patient (4.2%) during the operation, but the lesion was still successfully resected under VATS. Of those patients, 8 were confirmed to have a primary NSCLC by rapid pathologic diagnosis during VATS wedge resection, and then VATS lobectomies were performed. Condusion The preoperative CT-guided hookwire localization for small solitary pulmonary nodules is an effective and safe technique to assist VATS resection of the nodules.     

Dipole-source analysis in a realistic head model in patients with focal epilepsy

PURPOSE: By the use of three different head models in EEG dipole analysis, we tried to model the origin of interictal and ictal epileptic activity as precisely as possible. Further, as a control, a second evaluation was made by an independent group to control for interindividual reliability of the dipole source analysis. With the realistic head model (CURRY) considering cortex, skull, and skin segmentation, the spike source was located. METHODS: In five patients with mesial temporal epileptogenesis, confirmed by successful epilepsy surgery, the spike source was close to the hippocampus, with a mean distance of the dipole source from the hippocampus of 13.6 mm (range, 9-17.2 mm). In one case the ictal EEG also could be analyzed and resulted in a dipole-source localization comparable to the interictal source. RESULTS: In both head models using either pure cortex segmentation only or a concentric three-shell model, the dipole source was systematically dislocated in a more superior position. Data analysis by a second group with independently chosen EEG samples and identical individual head model resulted in deviations of <5.3 mm. Data analysis using independently selected spikes and independently segmented head models resulted in deviations < or =16.7 mm. CONCLUSIONS: In four cases of extratemporal epileptogenesis, the origin of interictal epileptiform discharges was localized to the suspected primary epileptogenic zone.     

阴道毛滴虫Rab1a重组蛋白的表达和细胞内定位

目的制备阴道毛滴虫(Trichomonasvaginalis,Tv)Rab1a重组蛋白及其多克隆抗体,并对TvRab1a蛋白进行阴道毛滴虫的细胞内定位。方法将我们已构建的pQE80L/TvRab1a重组表达质粒转入大肠埃希菌E.coliM15,在IPTG诱导下表达重组蛋白,经Ni-NTA亲和柱层析后获得纯度较高的TvRab1a的重组蛋白;用经复性处理的重组蛋白免疫动物,获得TvRab1a重组蛋白抗血清,免疫印迹WesternBlot鉴定抗血清。采用荧光免疫细胞化学对TvRab1a蛋白进行细胞内定位。结果WesternBlot分析显示,TvRab1a重组蛋白可与豚鼠的抗TvRab1a血清反应,同时该抗血清在滴虫提取蛋白中检测到与预测TvRab1a分子量一致的条带;免疫荧光化学检测发现TvRab1a分布于细胞核周围的高尔基复合体与内质网。结论获得的抗TvRab1a蛋白的多抗血清可用于TvRab1a基因功能的研究;TvRab1a功能场所位于高尔基复合体与内质网。     

Subcellular compartmentalization of a potassium channel (Kv1.4): preferential distribution in dendrites and dendritic spines of neurons in the dorsal cochlear nucleus

Voltage-dependent ion channels have specific patterns of distribution along the neuronal plasma membrane of dendrites, cell bodies and axons, which need to be unravelled in order to understand their contribution to neuronal excitability and firing patterns. We have investigated the subcellular compartmentalization of Kv1.4, a transient, fast-inactivating potassium channel, in fusiform cells and related interneurons of the rat dorsal cochlear nucleus. A polyclonal antibody which binds to a region near the N-terminus domain of a Kv1.4 channel was raised in rabbits. Using a high-resolution combination of immunocytochemical methods, Kv1.4 was localized mainly in the apical dendritic trunks and cell bodies of fusiform cells, as well as in dendrites and cell bodies of interneurons of the dorsal cochlear nucleus, likely cartwheel cells. Quantitative immunogold immunocytochemistry revealed a pronounced distal to proximal gradient in the dendrosomatic distribution of Kv1. 4. In plasma membrane localizations, Kv1.4 was preferentially present in dendritic spines, either in the spine neck or in perisynaptic locations, always away from the postsynaptic density. These findings indicate that Kv1.4 is largely distributed in dendritic compartments of fusiform and cartwheel cells of the dorsal cochlear nucleus. Its preferential localization in dendritic spines, where granule cell axons make powerful excitatory synapses, suggests a role for this voltage-dependent ion channel in the regulation of dendritic excitability and excitatory inputs.     

基于超声定位的火器贯穿伤标准化动物损伤模型的构建

目的:基于超声定位技术,构建一种模拟真实战场环境下的股动脉火器贯穿伤标准化动物损伤模型。方法:选择体质量指数与人体相当的10只长白猪作为实验对象,采用定制弹道步枪和欧盟制式子弹作为致伤武器,使用自制超声引导定位架作为辅助血管定位装置。采用超声探头定位实验动物左侧股动脉血管位置,利用超声引导定位架和致伤架将实验动物的股动脉血管中心调整至子弹弹道轨迹线上射击致伤。计算自由出血20 s实验动物体外失血量,测量实验动物体表弹道入口、出口处直径和体内弹道深度,并通过解剖观察股动脉受损情况。采用SPSS 26.0软件进行统计学分析。结果:采用自制的超声引导定位架可以构建相对稳定的股动脉火器贯穿伤标准化动物损伤模型,成功率约90%(9/10);实验动物体表弹道入口平均直径为(7.20±1.03)mm,出口平均直径为(93.30±33.06)mm,两者相比具有明显统计学差异(t=-8.16,P=0.000);实验动物体内弹道平均深度为(191.80±25.50)mm;致伤20 s后死亡实验动物和存活实验动物的平均失血量分别为(478.00±267.48)和(111.50±45.32)g,两者相比没有统计学差异(t= -2.75,P=0.070)。结论:采用自制的超声引导定位架构建的股动脉火器贯穿伤标准化动物损伤模型成功率高、重复性好,且实验动物伤情稳定,可以为新型止血材料和止血装置的研制提供可靠的模型依据。     

Pinging the brain with transcranial magnetic stimulation reveals cortical reactivity in time and space

BackgroundSingle-pulse transcranial magnetic stimulation (TMS) elicits an evoked electroencephalography (EEG) potential (TMS-evoked potential, TEP), which is interpreted as direct evidence of cortical reactivity to TMS. Thus, combining TMS with EEG can be used to investigate the mechanism underlying brain network engagement in TMS treatment paradigms. However, controversy remains regarding whether TEP is a genuine marker of TMS-induced cortical reactivity or if it is confounded by responses to peripheral somatosensory and auditory inputs. Resolving this controversy is of great significance for the field and will validate TMS as a tool to probe networks of interest in cognitive and clinical neuroscience.ObjectiveHere, we delineated the cortical origin of TEP by spatially and temporally localizing successive TEP components, and modulating them with transcranial direct current stimulation (tDCS) to investigate cortical reactivity elicited by single-pulse TMS and its causal relationship with cortical excitability.MethodsWe recruited 18 healthy participants in a double-blind, cross-over, sham-controlled design. We collected motor-evoked potentials (MEPs) and TEPs elicited by suprathreshold single-pulse TMS targeting the left primary motor cortex (M1). To causally test cortical and corticospinal excitability, we applied tDCS to the left M1.ResultsWe found that the earliest TEP component (P25) was localized to the left M1. The following TEP components (N45 and P60) were largely localized to the primary somatosensory cortex, which may reflect afferent input by hand-muscle twitches. The later TEP components (N100, P180, and N280) were largely localized to the auditory cortex. As hypothesized, tDCS selectively modulated cortical and corticospinal excitability by modulating the pre-stimulus mu-rhythm oscillatory power.ConclusionTogether, our findings provide causal evidence that the early TEP components reflect cortical reactivity to TMS.