Evaluation of clustering algorithms for gene expression data using gene ontology annotations / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Clustering is a useful exploratory technique for interpreting gene expression data to reveal groups of genes sharing common functional attributes. Biologists frequently face the problem of choosing an appropriate algorithm. We aimed to provide a standalone, easily accessible and biologically oriented criterion for expression data clustering evaluation.</p><p><b>METHODS</b>An external criterion utilizing annotation based similarities between genes is proposed in this work. Gene ontology information is employed as the annotation source. Comparisons among six widely used clustering algorithms over various types of gene expression data sets were carried out based on the criterion proposed.</p><p><b>RESULTS</b>The rank of these algorithms given by the criterion coincides with our common knowledge. Single-linkage has significantly poorer performance, even worse than the random algorithm. Ward's method archives the best performance in most cases.</p><p><b>CONCLUSIONS</b>The criterion proposed has a strong ability to distinguish among different clustering algorithms with different distance measurements. It is also demonstrated that analyzing main contributors of the criterion may offer some guidelines in finding local compact clusters. As an addition, we suggest using Ward's algorithm for gene expression data analysis.</p>

Prediction of ventilatory function in children and adolescents using backpropagation neural networks / 生理学报

The aim of this study is to develop backpropagation neural networks (BPNN) for better prediction of ventilatory function in children and adolescents. Nine hundred and ninety-nine healthy children and adolescents (500 males and 499 females) aged 10-18 years, all of the Han Nationality, were selected from Inner Mongolia Autonomous Region, and their heights, weights, and ventilatory functions were measured respectively by means of physical examination and spirometric test. Using the approaches of BPNN and stepwise multiple regression, the prediction models and equations for forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), forced expiratory flow at 25% of forced vital capacity (FEF25%), forced expiratory flow at 50% of forced vital capacity (FEF50%), maximal mid-expiratory flow (MMEF) and forced expiratory flow at 75% of forced vital capacity (FEF75%) were established. Through analyzing mean squared difference (MSD) and correlation coefficient (R) of the ventilatory function indexes, the present study compared the results of BPNN, linear regression equation based on this work (LR's equation), prediction equations based on the studies of Ip et al. (Ip's equation) and Zapletal et al. (Zapletal's equation). The results showed, regardless of sex, the BPNN prediction models appeared to have smaller MSD and higher R values, compared with those from the other prediction equations; and the LR's equation also had smaller MSD and higher R values compared with those from Ip's and Zapletal's equations. The coefficients of variance (CV) for FEF50%, MMEF and FEF75% were higher than those of the other ventilatory function parameters, and their increasing percentages of R values (ΔR, relative to R values by LR's equation) derived by BPNN were correspondingly higher than those of the other indexes. In sum, BPNN approach for ventilatory function prediction outperforms the traditional regression methods. When CV of a certain ventilatory function parameter is higher, the superiority of BPNN would be more significant compared with traditional regression methods.

Decreased expression of serum cortisol in patients with severe hepatitis / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the profile of serum cortisol levels in patients with severe hepatitis.</p><p><b>METHODS</b>Fifty patients with viral hepatitis (including 30 severe hepatitis patients and 20 chronic hepatitis B patients) were enrolled in this present study. Serum cortisol concentration was tested using radioimmunoassay. Furthermore, liver function, coagulation and other related laboratory indices were also determined.</p><p><b>RESULTS</b>Serum cortisol concentration of severe hepatitis group was lower than that of chronic hepatitis B group (P < 0.05) and lower than that of healthy controls (P < 0.05) serum cortisol concentration of severe hepatitis patients was significantly positively correlated with PTA (r = 0.445, P < 0.05); serum cortisol concentration has no relation with ALT in patients with severe hepatitis (P > 0.05), and serum cortisol concentration was significantly negatively correlated with the ratio of AST/ALT in patients with severe hepatitis (r = -0.367, P < 0.05). No significant relationship was found between serum cortisol concentration and total Bilirubin (P > 0.05). Serum cortisol concentration in death group of severe hepatitis was lower than that in survival group of severe hepatitis (P < 0.05). Of severe hepatitis patients with MELD score, the higher MELD score, the lower the cortisol concentration.</p><p><b>CONCLUSION</b>Cortisol concentration decreased in patients with severe hepatitis, which was related to functional liver reserve and disease severity. Cortisol can be related to the prognosis of severe hepatitis patients.</p>

Stereological measurement of rat's seminiferous tubule / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The morphological measurements of seminiferous tubules are important in the studies of testis tissues. The purpose of this study was to evaluate the feasibility of using a stereological method to measure the geometric parameters of seminiferous tubule and to optimize the method.</p><p><b>METHODS</b>A stereological image processing program was developed with Delphi for the stereological measurement. Fields of view were obtained from 15 healthy Wistar rats' testis tissues (n = 247). The diameter, area and volume of seminiferous tubule were estimated with the image processing program by two individual observers. The area results were compared with those obtained by the standard morphometric method of planimetry.</p><p><b>RESULTS</b>Diameter measurements showed the diameters of different seminiferous tubules were almost the same and the mean value of about 50 tubules could be a good representation of the whole structure. Area measurements indicated there was no significant difference between stereology and planimetry (P > 0.05). But the stereological method required about 45% less time. Volume measurement showed the inter-observer variability was small (P > 0.05) and the reproducibility of the stereological method was good.</p><p><b>CONCLUSION</b>The stereological technique was practical and efficient in the quantitative measurement of the rat's seminiferous tubule.</p>

Establishment of the database of the 3D facial models for the plastic surgery based on network / 中华整形外科杂志

<p><b>OBJECTIVE</b>To collect the three-dimensional (3D) facial data of 30 facial deformity patients by the 3D scanner and establish a professional database based on Internet. It can be helpful for the clinical intervention.</p><p><b>METHODS</b>The primitive point data of face topography were collected by the 3D scanner. Then the 3D point cloud was edited by reverse engineering software to reconstruct the 3D model of the face. The database system was divided into three parts, including basic information, disease information and surgery information. The programming language of the web system is Java.</p><p><b>RESULTS</b>The linkages between every table of the database are credibility. The query operation and the data mining are convenient. The users can visit the database via the Internet and use the image analysis system to observe the 3D facial models interactively.</p><p><b>CONCLUSIONS</b>In this paper we presented a database and a web system adapt to the plastic surgery of human face. It can be used both in clinic and in basic research.</p>

Development of an ECG signals analysis service system based on B/S / 中国医疗器械杂志

An online ECG signals analysis service system based on the network has been established and is introduced in this paper which integrates the advantages of the network, database and ECG analysis tools, providing on-line ECG signal analysis service. Users with the knowledge of general operation of a browser, can process the ECG data and get a real-time display of analysis results.

Short time ECG signal analysis based on the reconstruction of phase space / 中国医疗器械杂志

Based on the reconstruction of two-dimension phase space of time series of short ECG signals, the variation of the strange attractor geometry is described and two indices, VMI and VAI, are derived in this paper. The two indices can distinguish clearly the ECG signals of sinus rhythm, tachycardia and ventricular fibrillation. Stable results of VMI and VAI can be obtained by analyzing ECG signals of several seconds. They are expected to be used in the development of medical instruments for a fast realtime display of analysis results.