An intelligent system for diagnosis of the heart valve diseases with wavelet packet neural networks

In this paper, an intelligent system is presented for interpretation of the Doppler signals of the heart valve diseases based on the pattern recognition. This paper especially deals with combination of the feature extraction and classification from measured Doppler signal waveforms at the heart valve using the Doppler Ultrasound. Because of this, a wavelet packet neural network model developed by us is used. The model consists of two layers: wavelet and multi-layer perceptron. The wavelet layer is used for adaptive feature extraction in the time-frequency domain and is composed of wavelet packet decomposition and wavelet packet entropy. The multi-layer perceptron used for classification is a feed-forward neural network. The performance of the developed system has been evaluated in 215 samples. The test results showed that this system was effective in detecting Doppler heart sounds. The correct classification rate was about 94% for abnormal and normal subjects.     

中枢神经系统感染患者血清NSE和sICAM-1的改变

目的 :探讨中枢神经系统感染患者血清中NSE和sICAM 1水平的改变。方法 :采用ELISA法检测了 30例CNS感染的患者和 2 0例正常健康人血清中的NSE和sICAM 1水平。结果 :在CNS感染患者血清中NSE( 12 5 .6 8± 14 .38μg/L)和sICAM 1( 4 48.94± 96 .70μg/L)显著高于正常对照组的NSE( 6 .6 6± 1.2 5 μg/L)和sICAM 1( 2 91.78± 39.18μg/L) ,P <0 .0 1。在CNS感染各组中病毒性脑炎患者的NSE亦显著高于其他各组 ;sICAM 1在CNS感染各组间无显著性差异 ,P >0 .0 5。结论 :提示NSE和ICAM 1可作为CNS损害和感染的监测指标     

An integrative approach to CTL epitope prediction: a combined algorithm integrating MHC class I binding, TAP transport efficiency, and proteasomal cleavage predictions

Reverse immunogenetic approaches attempt to optimize the selection of candidate epitopes, and thus minimize the experimental effort needed to identify new epitopes. When predicting cytotoxic T cell epitopes, the main focus has been on the highly specific MHC class I binding event. Methods have also been developed for predicting the antigen-processing steps preceding MHC class I binding, including proteasomal cleavage and transporter associated with antigen processing (TAP) transport efficiency. Here, we use a dataset obtained from the SYFPEITHI database to show that a method integrating predictions of MHC class I binding affinity, TAP transport efficiency, and C-terminal proteasomal cleavage outperforms any of the individual methods. Using an independent evaluation dataset of HIV epitopes from the Los Alamos database, the validity of the integrated method is confirmed. The performance of the integrated method is found to be significantly higher than that of the two publicly available prediction methods BIMAS and SYFPEITHI. To identify 85% of the epitopes in the HIV dataset, 9% and 10% of all possible nonamers in the HIV proteins must be tested when using the BIMAS and SYFPEITHI methods, respectively, for the selection of candidate epitopes. This number is reduced to 7% when using the integrated method. In practical terms, this means that the experimental effort needed to identify an epitope in a hypothetical protein with 85% probability is reduced by 20-30% when using the integrated method.The method is available at http://www.cbs.dtu.dk/services/NetCTL. Supplementary material is available at http://www.cbs.dtu.dk/suppl/immunology/CTL.php.     

Dialysate-side urea kinetics. Neural network predicts dialysis dose during dialysis

Determination of the adequacy of dialysis is a routine but crucial procedure in patient evaluation. The total dialysis dose, expressed as Kt/V, has been widely recognised to be a major determinant of morbidity and mortality in haemodialysed patients. Many different factors influence the correct determination of Kt/V, such as urea sequestration in different body compartments, access and cardiopulmonary recirculation. These factors are responsible for urea rebound after the end of the haemodialysis session, causing poor Kt/V estimation. There are many techniques that try to overcome this problem. Some of them use analysis of blood-side urea samples, and in recent years, on-line urea monitors have become available to calculate haemodialysis dose from dialysate-side urea kinetics. All these methods require waiting until the end of the session to calculate the Kt/V dose. In this work, a neural network (NN) method is presented for early prediction of the Kt/V dose. Two different portions of the dialysate urea concentration-time profile (provided by an on-line urea minitor) were analysed: the entire curve A and the first half B, using an NN to predict the Kt/V and compare this with that provided by the monitor. The NN was able to predict Kt/V is the middle of the 4h session (B data) without a significant increase in the percentage error (B data: 6.69%±2.46%; A data: 5.58%±8.77%, mean±SD) compared with the monitor Kt/V.     

胎鼠脊髓神经干细胞与颌下腺颗粒曲管细胞联合培养的研究

目的研究颌下腺颗粒曲管细胞(GCT细胞)对脊髓神经干细胞(NSCs)增殖分化的影响。方法取胎鼠脊髓NSCs原代和传代培养,取成年雌、雄大鼠GCT细胞原代和传代培养,实验分为3组:NSCs和GCT细胞联合培养组;雌、雄大鼠GCT细胞培养上清液与NSCs培养液混合后培养NSCs;NSCs培养液组为对照组;免疫荧光细胞化学方法进行细胞鉴定,MTT法对比各组NSCs增殖活力。结果NSCs与GCT细胞联合培养7 d后Nestin阳性神经球数多于单独培养,雄性大鼠GCT细胞混合培养液组NSCs增殖活力最强,对照组NSC最弱,雌性混合培养液组介于两者之间。鉴定细胞球Nestin阳性,各组均有少量贴壁分化细胞。结论大鼠GCT细胞分泌物促进NSCs增殖,抑制分化,雄性大鼠GCT细胞作用比雌性大鼠显著。     

带臂外侧上皮神经及其营养血管筋膜皮瓣的应用解剖

目的:为带臂外侧上皮神经及其营养血管筋膜皮瓣提供解剖学基础.方法:32例经灌注红色乳胶的成人上肢标本,对臂外侧上皮神经及其营养血管等进行了较详细的应用解剖学研究.结果:臂外侧上皮神经在均由腑神经发出,起点横径为1.5±0.4mm,在三角肌深方斜向外下3.6±1.1cm从该肌后缘中1/3浅出肌间隔,分为上支和下支,分布于三角肌后部、外侧部和臂外侧上部.该神经的营养血管起源于旋肱后动脉,起点外径为0.9±0.4mm;其行程、分支和分布均同在神经,供血范因为14.8×9.8cm~2,并与周围的皮动脉存在丰富吻合.结论:带臂外侧上皮神经及其营养血管筋膜皮 瓣可视受区需要设计成游离瓣或旋转瓣,用于修复邻近部位、手或颌面部缺损.     

Occurrence of neural tube defects among first-, second-, and third-degree relatives of probands: Results of a United States study

Data on the occurrence of neural tube defects in first-, second-, and third-degree relatives of probands were collected in a United States study. The proportions of affected individuals were 3.2%, 0.5%, and 0.17% respectively. These findings are compared to those from other recent North American studies, and differences are discussed. It is pointed out that accurate recurrence risk figures may not be available, and that caution should be used when counseling families with relatives who are affected with NTD.     

Neural dynamics in cortex-striatum co-cultures-II. Spatiotemporal characteristics of neuronal activity

Neural dynamics in organotypic cortex-striatum co-cultures grown for three to six weeks under conditions of dopamine deficiency are described. Single neuron activities were recorded intra- and extracellularly, and spatiotemporal spreading of population activity was mapped using voltage-sensitive dyes. The temporal properties of spike firing were characterized by interspike interval histograms, autocorrelation and crosscorrelation.

Cortical pyramidal neurons (n = 40) showed irregular firing with a weak tendency to burst or to oscillate. Crosscorrelations revealed strong near-coincident firing and synaptic interactions. Disinhibition was a notable feature in a strongly firing cortical interneuron. Cortical activity spread in the co-culture, thus inducing an overall, homogeneous depolarization in the striatal part. Striatal cells were divided into principal cells and type I and II secondary cells. Principal cells (n = 40) were similar to those reported previously in vivo. Spiking activity ranged from irregular spiking at very low rates to episodic bursting, with an average burst duration of 1 s. Interspike intervals were single-peaked. Intracellular recordings revealed characteristic, long-lasting subthreshold depolarizations (“enabled state”) that were shortened by local muscarinic receptor blockade. During prolonged time periods in the “enabled state”, locally applied bicuculline induced strong firing in most principal neurons. Striatal secondary type I neurons (n = 25) showed high spiking rates, single- and double-peaked interval histograms and low-threshold, short-lasting stereotyped bursting activity and occasional rhythmic bursting. The firing of these neurons was increased by bicuculline. Crosscorrelations showed synchronization of these cells with principal cell activity. Secondary type II neurons (n = 15) revealed tonic, irregular firing patterns similar to cortical neurons, except with occasional firing in doublet spikes.

We conclude that under conditions of dopamine deficiency in corticostriatal co-cultures (i) the cortex induces the “enabled” state and typical bursting mode in striatal principal neurons; (ii) principal neurons are strongly inhibited during the “enabled” state; (iii) muscarinic activity, presumably from tonically active striatal cholinergic interneurons, stabilizes the “enabled” state; (iv) striatal GABAergic interneurons receive synaptic inhibition and take part in synchronized activity among striatal principal cells. Our results favor the view of the striatum as a lateral inhibition network.     

T细胞转录因子-4在大鼠脑缺血再灌注海马齿状回神经干细胞中的表达

目的:检测T细胞转录因子-4(Tcf-4)在大鼠脑缺血再灌注海马组织神经干细胞中的表达及其变化。探讨影响神经干细胞早期增殖分化的分子调控机制。方法:采用大脑中动脉栓塞(MCAO)制作大鼠脑缺血再灌注模型。用免疫组织化学SP法及RT-PCR法检测海马神经干细胞BrdU、Tcf-4中的表达。结果:随着脑缺血再灌注第3日齿状回神经元BrdU阳性细胞明显增多,第7日达高峰,然后逐渐减少。Tcf-4 mRNA反应产物随脑缺血再灌注时间延长逐渐增多,第21日表达最强,以后表达逐渐减少。结论:Tcf-4时间依赖性表达与神经干细胞增殖分化进程相吻合,说明其在神经干细胞晚期分化中起重要调控作用。     

Real-time ocular artifact suppression using recurrent neural network for electro-encephalogram based brain-computer interface

The paper presents an adaptive noise canceller (ANC) filter using an artificial neural network for real-time removal of electro-oculogram (EOG) interference from electro-encephalogram (EEG) signals. Conventional ANC filters are based on linear models of interference. Such linear models provide poorer prediction for biomedical signals. In this work, a recurrent neural network was employed for modelling the interference signals. The eye movement and eye blink artifacts were recorded by the placing of an electrode on the forehead above the left eye and an electrode on the left temple. The reference signal was then generated by the data collected from the forehead electrode being added to data recorded from the temple electrode. The reference signal was also contaminated by the EEG. To reduce the EEG interference, the reference signal was first low-pass filtered by a moving averaged filter and then applied to the ANC. Matlab Simulink was used for real-time data acquisition, filtering and ocular artifact suppression. Simulation results show the validity and effectiveness of the technique with different signal-to-noise ratios (SNRs) of the primary signal. On average, a significant improvement in SNR up to 27 dB was achieved with the recurrent neural network. The results from real data demonstrate that the proposed scheme removes ocular artifacts from contaminated EEG signals and is suitable for real-time and short-time EEG recordings.