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.

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

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

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.

Objective:To analyze retrospectively the risk factors for pulmonary infection after traumatic cervical spinal cord injury.Methods:The 154 patients with a cervical spinal cord injury studied included 120 with a pulmonary infection and 34 uninfected controls. Regressions were evaluated using data on their genders, ages, the cause of injury, affected segments, the neurological level of the injury (NLI), and the presence of a vertebral fracture or dislocation.Results:Age, complete injury, NLI at C 1 to C 4, and an injury-to-treatment time of more than 8 hours were found to be independent risk factors for secondary pulmonary infection. Conclusion:Elderly spinal cord injury patients, with a complete injury, an NLI between C 1 and C 4 or an injury-to-treatment time of more than 8 hours have a higher risk of pulmonary infection.

Objective:To investigate the alterations of amplitude of low frequency fluctuation (ALFF) and functional connectivity (FC) in patients with Parkinson′s disease (PD) with apathy.Methods:From May 2016 to August 2019, PD patients and age-, gender-and education level-matched healthy controls (HC) in the First Affiliated Hospital of Nanjing Medical University were prospectively recruited. The clinical and resting-state functional MRI (rs-fMRI) data of PD patients and HC were analyzed. According to the Starkstein Apathy Scale (SAS) scores, PD patients were divided into PD with apathy (PD-A) group and PD without apathy (PD-NA) group. Rs-fMRI images were processed by DPABI based on MATLAB. ALFF values were calculated and the standard ALFF (zALFF) were obtained. ANOVA and Post-Hoc t test were performed to compare the differences in local brain activity among the three groups. The brain regions with significant different zALFF values were selected as the seeds to calculate the FC values of the whole brain. The associations between FC values and the SAS scores were performed using pearson correlation analyses. Results:A total of 75 PD patients (50 males, 25 females, aged from 44 to 88 years) and 41 HC (25 males, 16 females, aged from 54 to 72 years) were enrolled. There were 42 patients in the PD-A group and 33 patients in the PD-NA group. Significant differences were found in zALFF values among the PD-A, PD-NA and HC groups ( P<0.05). After Post-Hoc t test, compared with the HC group, zALFF values were significantly increased in the right middle frontal gyrus in the PD-A group ( P<0.05) and significantly decreased in the left precuneus in the PD-NA group; The zALFF values of the right middle frontal gyrus and left precuneus in the PD-A group were significantly higher than those in PD-NA group ( P<0.05). Brain regions with different zALFF values were used as seeds for whole-brain FC. Compared with PD-NA group, FC values between the right middle frontal gyrus and bilateral precuneus, left superior frontal gyrus and its medial side, left middle frontal gyrus, left angular, left anterior cingulate gyrus, left posterior cingulate gyrus, left parahippocampal gyrus were significantly decreased in the PD-A group ( P<0.05). Additionally, FC values of PD patients between the right middle frontal gyrus with the left precuneus, the left superior frontal gyrus and its medial side, and the left middle frontal gyrus were negatively correlated with SAS scores ( r=-0.31, -0.30 and -0.34, both P<0.05). Conclusion:PD-A and PD-NA patients have different brain functional activities and connections in the frontal lobe, parietal lobe and limbic system, suggesting that apathy in PD may be associated with the abnormal functional connections of the frontal-parietal cortical circuit and the frontal-limbic-striatal loop.