A liquid chromatography-tandem mass spectrometry ( LC-MSMS ) method has been developed for the simultaneous determination of N3-methyladenine ( N3-MeA ) and N3-ethyladenine ( N3-EtA ) in calf thymus DNA. The DNA samples has been purified and enriched by cation exchange cartridge ( Waters Oasis MCX) . d3-N3-MeA and d5-N3-EtA were used as isotope internal standard. The DNA samples were injected with autosampler. The injected volume was 3 μL and analysis time was 13 min. The sample separation was carried out on hydrophilic interaction chromatograph ( Waters XBridge HILIC ) with 10 mmol/L ammonium formate-acetonitrile (5:92, V/V, pH=4. 0) as mobile phase. The flow rate was set at 250 μL/min. Mass spectrometry was performed by electrospray ionization ( ESI ) with multi-reactions monitoring ( MRM ) . The optimized operation conditions of MS were as follows: nebulizer gas 369 Pa; curtain gas 185 Pa, turbo ionspray temperature 400 ℃, ionspray voltage 5500 V, dwell time 40 ms. The limits of detection were 0. 043 and 0. 007 μg/L for N3-MeA and N3-EtA, respectively. The recoveries were between 87. 8% and 103. 0%for N3-MeA and N3-EtA. This method was successfully applied to the determination of N3-MeA and N3-EtA in calf thymus DNA by cigarette smoke condensate ( CSC) exposure. This method is appropriate for routine analysis and accurate quantification of N3-MeA and N3-EtA by CSC exposure.

Liver biopsy plays an important role in the diagnosis and treatment of liver diseases and can give a comprehensive and detailed description of the morphology of lesions and objective grading and staging scores. There are several pathological grading and staging systems for chronic viral hepatitis and chronic hepatitis due to other causes. This article describes the application and advantages/disadvantages of each scoring system and summarizes related precautions.

Based on human ventricular single cell mathematical model, a two-dimensional mesh of ventricular wall tissue was constructed. Through the increasing of the concentration of extracellular K+, we simulated the propagation of spiral wave in a condition under the influence of ischemia in 2-D human ventricular tissue. The results showed that along with the increase of ischemic level and size, the instability of spiral waves increased, and under the influence of certain ischemic level and size, spiral waves broke up. Through this simulation study of the effects of ischemia on spiral waves in 2-D human ventricular tissue, we explained the corresponding mechanism of the maintenance of ventricular tachycardia and the cause of ventricular fibrillation under the influence of ischemia.
Arrhythmias, Cardiac ; etiology ; physiopathology ; Computer Simulation ; Heart Ventricles ; Humans ; Models, Cardiovascular ; Myocardial Ischemia ; complications ; physiopathology ; Tachycardia, Ventricular ; etiology ; physiopathology ; Ventricular Fibrillation ; etiology ; physiopathology

In this paper, we present an experimental research on the frameless registration of DSA/CT images based on frameless localization algorithm. The result shows that, 3D fusion and registration of vessels in the DSA images and anatomical structures in CT images will help surgeons to make accurate diagnosis and on plann operative.
Algorithms ; Angiography, Digital Subtraction ; methods ; Cerebral Angiography ; Humans ; Image Processing, Computer-Assisted ; methods ; Imaging, Three-Dimensional ; Tomography, X-Ray Computed ; methods

OBJECTIVETo investigate the clinical value of ultrasound-guided laser thermal ablation (LTA) in the treatment of small liver cancer at high-risk sites.

METHODSA total of 73 lesions ablated with LTA in 68 patients with small liver cancer. After the operation, the rates of complete ablation were compared between patients with lesions of different sizes and at different sites using contrast-enhanced ultrasound and the complications were recorded during the follow-up.

RESULTSThe complete ablation rates for carcinomas ≤1 cm, 1-2 cm, and 2-3 cm were 100%, 86.4%, and 82.7%, respectively, showing no significant differences among them (P>0.05). The complete ablation rates of lesions were similar between the high-risk and low-risk groups (85.7% vs 92.1%; P>0.05). The two groups showed no significant difference in the incidence of complications (9.1% vs 5.7%; P>0.05).

CONCLUSIONUltrasound-guided LTA can be a good option for treatment of small liver cancers at high-risk sites.

Contrast Media ; Follow-Up Studies ; Humans ; Laser Therapy ; methods ; Lasers ; Liver Neoplasms ; therapy ; Treatment Outcome ; Ultrasonic Therapy

Objective To verify and compare the TI-RADS developed by Kwak et al .( Kwak TI-RADS ) ,2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer ( ATA Guideline Classification) ,2017 TI-RADS released by the American College of Radiology (ACR TI-RADS) and TI-RADS developed by Zhou et al .(Zhou TI-RADS) in the evaluation of thyroid nodules . Methods The ultrasound images of 339 thyroid nodules in 273 patients were analyzed by retrospective study . The thyroid nodules were categorized into aforementioned four stratified systems . Based on the pathological findings considered the "gold standard",the receiver operating characteristic( ROC ) curve was created to compare the clinical application value of aforementioned four stratified systems . Results The percentage of nodules that could not be categorized were 1 .2％ ,17 .5％ ,0 and 1 .2％ for the Kwak TI-RADS ,ATA guidelines ,ACR TI-RADS ,and Zhou TI-RADS ,respectively and the area under the ROC curve ( AUC) was 0 .899 ,0 .879 ,0 .876 ,and 0 .918 ,respectively . The sensitivity of Kwak TI-RADS ,ATA guidelines classification ,and ACR TI-RADS were higher than that of Zhou TI-RADS (all P < 0 .05) ,whereas the specificity of Zhou TI-RADS was the highest (all P < 0 .05) . As for the accuracy ,no statistically significant differences were observed between any two of Kwak TI-RADS ,ATA guidelines ,ACR TI-RADS ,and Zhou TI-RADS systems ( all P > 0 .05) . Conclusions Four thyroid risk stratification systems provide effective risk assessment for thyroid nodules ,Zhou TI-RADS has relatively lower sensitivity ,but its specificity and AUC value are the highest among the four evaluated systems . In addition ,ACR TI-RADS can classify the most nodules ,while the number of nodules that can′t be categorized by ATA guideline is maximum .

Objective To assess the knowledge and attitude towards hierarchical medical system among patients in Beijing Xicheng district community health service centers.Methods A questionnaire survey was conducted between July and August 2016,among randomly-selected patients who were visiting community health service centers in Beijing Xicheng district.Results A total of 2 770 patients were investigated.The percentage of patients who knew the hierarchical medical system was 62.2％ (1 722/2 770).Logistic regression showed that the degree of knowledge was significantly correlated with the visit number in the recent year and the education levels of patients.The percentage of patients who had a positive attitude to the system was 89.5％ (2 478/2 770).The main reasons for negative attitude to the system were "worry about the delay of treatment","inconvenience" and "fewer drugs in community health service centers" and "weak capacity of community health service centers".Logistic regression showed that the education level was negatively correlated with the attitude.In the case of mild illness,2,485 (89.7％) participants would chose "community health service center or service station".Conclusions The knowledge of hierarchical medical system among patients in community health institutions are moderately high,while most of them have positive attitude towards the system.The service capacity of community health service institutions should be further improved,and publicity should be strengthened to improve the awareness of hierarchical medical system among community residents.

Objective To investigate the correlation between non-alcoholic fatty liver disease(NAFLD)and coronary artery plaque and perivascular adipose tissue(PVAT)parameters.Methods A total of 119 patients who underwent liver ultrasound and coronary computed tomography angiography(CCTA)examination were selected and divided into NAFLD group(50 cases)and non-NAFLD group(69 cases).The types of coronary artery plaque,plaque vulnerability,plaque involvement length,plaque load,vascular remode-ling,degree of vessel stenosis,and parameters of pericoronary fat[pericoronary fat attenuation index(pFAI),pericoronary fat total volume of voxels(pFV),perivascular water attenuation index(PVWI)]were evaluated.The data were analyzed statistically.Results The incidence of vulnerable plaque in NAFLD group was higher than that in non-NAFLD group,and the difference was statistically significant(P＜0.001).The incidence of positive vascular remodeling in NAFLD group was higher than that in non-NAFLD group,the incidence of no remodeling was the opposite,and the differences were statistically significant(P=0.001).The incidence of non-calcified plaque in NAFLD group was higher than that in non-NAFLD group,and the incidence of calcified plaque was the opposite(P=0.011).The incidence of severe stenosis in NAFLD group was higher than that in non-NAFLD group,and the incidence of moderate stenosis was the opposite,with statistical significance(P=0.004).The pFAI and plaque load in NAFLD group was higher than that in non-NAFLD group,and the pFV value was lower than that in non-NAFLD group,with statistical significance(P＜0.001,P=0.029,P=0.002).Conclusion The incidences of vulnerable plaque,positive remodeling,non-calcified plaque,vascular severe stenosis,and plaque load are significantly higher in NAFLD group than those in non-NAFLD group.In addition,pFAI increases and pFV decreases in NAFLD group.

BACKGROUND:As a leading technique in the treatment of primary stenosis by posterior spinal endoscopy through unilateral approach and bilateral decompression using single channel endoscopy,the long-term efficacy needs to be further observed.There are few reports on the scope of intraoperative resection and few relevant studies on biomechanics and finite element analysis. OBJECTIVE:A three-dimensional finite element model was established to evaluate the effects of bilateral lumbar canal decompression under a one-hole split endoscope on lumbar range of motion and intradiscal pressure,to provide suggestions for clinical operation and theoretical basis for further clinical research. METHODS:A complete L3-L5 vertebral body model was reconstructed by CT images of nine healthy volunteers,which was used as the preoperative model M1.The simulated surgical resection range of L4-L5 was performed,and 1/4,1/3 and 1/2 of bilateral facet joints were removed respectively to obtain models M2,M3 and M4.The range of motion and the maximum Von Mises stress of the four models were compared in the six directions of forward bending,backward extension,left and right bending,and left and right rotation. RESULTS AND CONCLUSION:(1)The L3-L5 finite element model established in this study was effective,and the range of motion was within the range of previous solid studies under six motion states.(2)Compared with the M1 model,the L4-L5 lumbar spine range of motion increased with the increase of resection range in M2 with M3 and M4 models under forward bending,left and right bending and left and right rotation loading,and the difference was significant(P＜0.05).Under posterior extension loading,there was no significant difference in lumbar range of motion between M1 and M2(P＞0.05),but there was a significant difference of M1,M3 and M4(P＜0.05).(3)The range of motion of the L3-L4 lumbar spine had no significant change with the increase of bilateral facet arthrotomy(P＞0.05).(4)There was a significant difference in the maximum value of L4-L5 Von Mises between M1 and M2(P＜0.05),and there was a significant difference in the maximum value of L4-L5 Von Mises between M1 and M3,M4(P＜0.01),and the maximum value of L4-L5 lumbar von Mises increased with the increasing range of bilateral facet joint resection.Resection of more than 1/3 was particularly obvious.(5)The maximum value of Von Mises in the L3-L4 lumbar spine was increased with the increase of the resection range under forward bending,left and right bending and left and right rotation loading and the difference was significant(P＜0.05).(6)The results exhibited that the L4-L5 lumbar motion and intervertebral disc pressure increased with the increase of the excision range.Intervertebral disc pressure at L3-L4 increased with the increased extent of excision,but the lumbar range of motion was not significantly affected.In conclusion,the stability of the operative segment may be affected by the increase in the scope of facet joint resection.Although the immediate stability of adjacent segments is not affected,it may accelerate disc degeneration.

Histopathological evaluation based on liver biopsy is required to make a confirmed diagnosis of nonalcoholic fatty liver disease, differentiate nonalcoholic fatty liver (NAFL) from nonalcoholic steatohepatitis (NASH), and perform the grading and scoring of disease severity, while hematological and radiological examinations are often used in clinical practice. Although there have been a large number of studies on noninvasive models for fibrosis assessment and disease diagnosis in nonalcoholic fatty liver disease, the sensitivity and specificity of such models need to be further improved. This article reviews the main pathological features of NAFL and NASH, fibrosis and grading/staging/scoring systems, and the pathological diagnosis of NASH liver cirrhosis, in order to improve the awareness of the histological diagnosis of such disease among clinicians