Progressive network impairment in patients with chronic hepatitis B virus related cirrhosis: a combined resting-state functional MRI and diffusion tensor imaging study / 中华放射学杂志

Objective:To explore the disease-related impairment of functional and structural connectivity network and their relationship with psychometric hepatic encephalopathy score (PHES) in patients with chronic hepatitis B virus-related cirrhosis (HBV-RC) by combining resting-state functional MRI (rs-fMRI) and diffusion tensor imaging (DTI).Methods:Data of 30 HBV-RC patients [including 13 HBV-RC patients with minimal hepatic encephalopathy (MHE) and 17 HBV-RC patients without MHE (NMHE)] from April 2011 to October 2011 in Guangdong No.2 People′s Hospital were analyzed prospectively, and 38 healthy individuals matched for age, sex, and education with HBV-RC patients (HC group) were included during the same period. Rs-fMR and DTI data as well as PHES data of all participants were collected. Gretna and PANDA software package were used to preprocess the imaging data and construct the functional and structural network respectively. The network-based statistic (NBS) approach was used to compare the differences of the functional and structural connections among three groups. Spearman′s correlation analysis was used to identify the relationship between functional or structural connectivity and PHES. The structural equation modeling (SEM) was used to explore the relationships among functional connectivity, structural connectivity, and PHES.Results:Compared to HC group, both functional and structural connectivity in the whole brain progressively destroyed from NMHE to MHE, mainly involving cognitive control network, default mode network, and limbic network (NBS corrected, all P<0.01). There were significantly negative relationships between functional or structural connectivity and PHES in HBV-RC patients (false discovery rate corrected, all P<0.05). The SEM results showed the influence of structural connectivity on neurocognitive impairment was mediated by functional connectivity ( P<0.05). Conclusion:Both functional and structural networks progressively destroy in HBV-RC patients as the disease advanced and these alterations significantly correlate with PHES. Besides, the influence of structural connectivity on neurocognitive impairment is mediated by functional connectivity.

Exploration and practice of"5+3"integrated training model / 中华医学教育探索杂志

"5+3" integrated training program is a new training model to cultivate doctors under the background of preclinical teaching and clinical training integration. Based on practice in Shantou University Medical College, the program design current progress and solution to the problem were elaborated. It adheres to principles of overall optimization and orienting to clinic, and to ensure the smooth implementation of the training model. Which will provide important reference for the reform of long-term medical training program in higher medical colleges and universities.

High Throughput Screening of 86 Kinds of Glucocorticoids in Cosmetics Using QuEChERS and Isotope Dilution-Liquid Chromatography Copuled to High Resolution Time-of-Flight Mass Spectrometry / 分析化学

A high throughput screening method based on QuEChERS purification and stable isotope dilution-liquid chromatography coupled to high resolution time-of-flight mass spectrometry was developed for the simultaneous rapid determination of 86 kinds of glucocorticoids (GCs) in cosmetics.The analytes were extracted by acetonitrile, and then the extracts were purified using an improved QuEChERS method.The chromatographic separation was performed on a novel multiple chromatographic retention mechanisms column of Poroshell 120 PFP (100 mm × 2.1 mm, 2.7 μm) with gradient elution using 0.2% (V/V) acetic acid and acetonitrile as mobile phase.The accurate mass database of parent ions and mass spectra library of fragment ions of 86 GCs were established under positive ionization mode with electrospray ionization source.Based on the method described above, the qualitative identifications of the 86 GCs were accomplished without the contrast of standard substances.The results demonstrated that the linear range of this method was from 2 μg/L to 200 μg/L with good correlation coefficients of R2>0.99.The average recoveries of the 86 GCs ranged from 66.2% to 112.8%, and the relative standard deviation (RSDs) was 4.6%-13.9% at three different spiked levels.The limit of detection (LOD) and quantification (LOQ) were 0.006-0.015 mg/kg and 0.02-0.05 mg/kg, respectively.The method is simple, efficient, reliable and accurate, and is suitable for high throughput screening of 86 GCs added illegally in cosmetics.

Study of Stainless Steel Solid Phase Microextraction Fiber for Selective Absorption of Impurities in Gutter Oil / 分析化学

A special solid phase micro extraction ( SPME ) fibre was successfully attained by coating with a special adsorptive material on a porous stainless steel support. And the porous stainless steel support was prepared by electrochemical corrosion for the first time. The optimized erosion condition in this research was as follows: the current intensity of 30 mA, the stainless steel was etched in 2 mol/L hydrochloride solution for 1 min, then sonicated for 3 min; these procedures repeated 5 times. Meanwhile, the treated fiber coated 35 times in the sorbent solution with concentration of 5% ( m/V) in dichloromethane. The SPME fibre was applied to the analysis of gutter oil samples, and the performance of the SPME fibre for the headspace solid phase micro extraction of the exogenous impurities in gutter oil was specific, durable, stable and low-cost. The four detected trace level characteristic impurities in certain gutter oil were given as follows:42 . 7 mg/kg for acetic acid, 21. 6 mg/kg 3-butenenitrile, 71. 8 mg/kg carbon disulfide and 2. 8 mg/kg allylisothiocyanate.

Rapid Screening of Carbamates Pesticide Residues in Vegetables by Electrospray Ionization Mass Spectrometry Based on Principle of Enzyme Inhibition / 分析化学

Arapidscreeningmethodforthedeterminationofcarbamatepesticides(CBPs)residuesin vegetables by measuring acetylcholinesterase ( AChE ) inhibition rate using electrospray ionization mass spectrometry ( ESI-MS ) has been established. After pretreatment by QuEChERS method, sample solution reacts with AChE using acetylthiocholine as substrate. AChE inhibition rate was calculated by determination of the conversion of substrate to product ( thiocholine) using ESI-MS. The temperature, time and concentration conditions of enzymatic reactions have been optimized. The relationship between the concentration of 10 kinds of common CBPs and AChE inhibition rate was researched. Matrix effects of real vegetables were studied. The limit of detection ( LOD) , which was measured by 3 times of enzyme inhibition rate of pesticide-free vegetable samples, was 0. 01-0. 05 mg/kg. The results showed that the method was better than the current national standard method of china for rapid screening of pesticide residues and fully meet the requirements of maximum residue limits( MRL) for pesticides in food of national food safety standard. False positive results were avoided effectively due to its good ability of resistance matrix interference. The reliability was proved by analyzing vegetables with liquid chromatography-tandem mass spectrometry. The method is simple, rapid, sensitive, reliable, and can be used for the rapid, high-throughput screening of CBPs in vegetables.

Fast Volume Clipping of Medical Images on GPU / 中国医学物理学杂志

Objective: When the region of interest is somewhere in the middle of the volumetric data, it will be occluded by other regions of the volumetric data and will be hard to see in the reconstruction of volume rendering. In order to provide doctor with comprehensive, visual and accurate diagnostic information, fast volume dipping of medical images on GPU is proposed in the paper. Methods: The rapid volume clipping is achieved by combining the dipping algorithm with the fast volume rendering algorithm based on GPU. The technique is based on fast volume tendering of medical images on GPU. It works as follows: The space information of the section plane is sent to the shader. Then compare the position of the volume data sets with the section plane to decide whether the data is clipped or not. Our algorithm is different from the algorithm that clipping based on depth stencil. We can see the result that reconstructed from the data sets that remained from any position as long as the section plane is defined. Results: According to the shape the users defined, our algorithm can decide which parts of the volume have to be clipped. Because of using the general graphics hardware acecleration, the proposed method achieves interactive display rate. Conclusions: The experiment shows that the algorithm is significantly fast and can meet the requirements of real-time interactive rendering on the premise of ensuring imaging quality and can be used in surgery simulation and so on.

Study on the In- vitro Recovery of Tetramethylpyrazine Phosphate in Microdialysis Probe / 中药新药与临床药理

Objective To detect the in-vitro recovery of tetramethylpyrazine phosphate (TMPP) in microdialysis probe and to study its stability. Methods The recovery of TMPP was detected by concentration difference method (increment method and decrement method ). The effect of flow rates and concentrations on recovery was studied. Results The recovery detected by increment method was as the same as that detected by decrement method; TMPP recovery was independent of TMPP concentration in the external medium. TMPP recovery had good stability. Conclusion Microdialysis sampling can be used for the pharmacokinetic study of TMPP and decrement method (ie. retrodialysis) can be used for the determination of TMPP recovery.