Based on practice of video-cases teaching,this paper put forwards four sorts of contradictions,which are the contradiction between time limitation of classroom and expressing limi-tation of video cases,the contradiction between relative independence of video cases (part)and con-sistency of teaching objective (entirety),the contradiction between apparentness of video cases (phe-nomenon)and depth of teaching content (essence)and the contradiction between variability of video case class and control of class by teachers. This paper suggested teaching principle of part conforming to entirety. Meanwhile,it indicated that classroom video case teaching should have strict design, closely coordinated class discussion and teachers should be good at guiding and summarizing. Through these efforts,the above four contradictions can be resolved and designed video case teaching obtained good effect.

Objective To establish a HEK293 cell line stably and highly expressing sense and antisense Alu-Sx.Methods According to Alu subfamily Sx sequence,a pair of primers containing the sites for given restrictive endonuclease at both ends were designed and synthesized.PCR of the total DNA extracted from HEK293 cell line was performed,the products of which were cloned into a highly efficient eukaryotic expression vector pcDNA3.1/myc-His A.The recombinants were sequenced and identified by restrictive endonuclease digestion and then transfected into the HEK293 cell line by lipofectamine2000.The stable transfectants were screened by G418.Cell subclones were isolated by gradient dilution.The highly expressing clones were identified by Northern blotting.Results Eukaryotic expressing vectors stably and efficiently expressing sense and antisense Alu-Sx were constructed and cell subclones stably and efficiently expressing sense and antisense Alu-Sx were established.Conclusion Cell subclones stably and efficiently expressing sense and antisense Alu-Sx can used for our further study.

BACKGROUND: Silibinin has broad pharmaceutical effects, such as anti-free radicals, anti-lipid peroxidation, anti-lipoid oxidase, anti-glutathione (GSH) depletion, anti-neoplastic and serum lipid-lowering effects. Clinically, silibinin is often used in treating alcoholic liver disease. OBJECTIVE: To investigate the pharmacological mechanism of silibinin for alcoholic fatty liver in rats. DESIGN: Randomized and controlled study.SETTING: Guangzhou Hospital of Traditional Chinese Medicine.MATERIALS: The experiment was conducted at the Animal Experimental Laboratory of Guangdong Pharmaceutical Institute from August to October 2003. Totally 57 SD rats, without unusual bacteria, weighting (150±10)g and of either gender, were selected. Yiganling tablets containing 38.5 mg silibinin were produced by Zhuzhou No.3 Pharmaceutical Factory (Batch No. 20020808).METHODS: Among the 57 SD rats, 18 rats were regarded as normal control group. Rats in normal control group were administered with normal saline by gavage, and fed with normal food and distilled water in place of alcohol for 10 weeks. Rats in model group and silibinin group were fed with high-calorie food and 100 mL/L alcohol for 6 weeks to establish model of rat alcoholic fatty liver. The other rats were divided into model control group (n=18) and silibinin group (n=21). Rats in model control group were treated with distilled water while those in silibinin group were treated with 100 mg/kg silibinin. Meanwhile, 100 mL/L ethanol and hyperalimentation feed were given for 4 weeks. After animals were killed, TG, SOD, GSH and MDA levels were measured with liver suspension.MAIN OUTCOME MEASURES: Contents of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP), total cholesterol (TC), triacylglycerol (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), tumor necrosis factor (TNF)-α , and transforming growth factor (TGF)-β1.RESULTS: All the 57 rats entered the final analysis. Silibinin could inhibit the activities of serum AST, ALT and AKP [(2 550.5±400.1), (533.4±100.0), (2 217.1±750.2)nkat/L], and the differences were significant as compared with those in model control group [(3 600.7±666.8), (800.2±100.0), (2 900.6±1 333.6) nkat/L, P ＜ 0.05-0.01]. Contents of TG, LDL-C, TNF-α and TGF-β1 in silibinin group [(1.8±0.8), (0.17±0.04), (6.66±1.38), (24.1±4.1) mmol/L] were lower than those in model group [(2.8±1.4), (0.20±0.05), (7.81±1.06), (28.8±6.3) mmol/L] with significant differences (P ＜ 0.05-0.01). Silibinin could increase the content of HDL-C but decrease the contents of TG and MDA (P ＜ 0.05-0.01), and improve SOD activity as well as hepatocyte and fatty degeneration (P ＜ 0.01).However, it had no obvious effect on the content of reduced estathion (P ＞ 0.05).CONCLUSION: Silibinin can inhibitthe formation of alcoholic fatty liver in rats. The pharmacological mechanism of silibinin may involve anti-oxidation, removing free radicals, inhibiting lipid peroxidation, regulating blood lipid component, reducing fatty sediment in liver, and anti-immunoinflammation and anti-hyperplasia effects.

Objective To evaluate the dynamic contrast-enhanced MRI (DCE-MRI)in detecting experimentally induced testicular ischemia. Methods Thirty healthy male New Zealand rabbits were randomly assigned into 6 groups. There were 5 rabbits in each of the following experimental groups: ( 1 ) Normal control, (2) Sham-operated, (3) ischemia of 3 h group, (4) ischemia of 6 h group, (5) ischemia of 12 h group, (6) ischemia of 24 h group. In all experiment groups, the right testis served as the internal control while the left testis served as the experimental side. DCE-MRI for each animal lasts about 10 minutes. Signal enhanced ratios (SERs) of ROI for both sides of each group were calculated by a computer, and parameters of SERs of 30 s, 75 s, 120 s and maximal SER were used for statistical analysis.Time intensity curves (TICs) were made for two sides of each group via Excel 2003 software and classified into 4 types. Statistical analysis was performed to compare the differences of SERs between left and right testis by two independent Kolmogorov-Smirnov test. Results In group I and 2, significant enhancement was observed on both testes of 10 rabbits. The enhancement decreased gradually with the elongation of ischemia in torsion groups. Three cases of type Ⅰ and 2 cases of type Ⅱ were observed in group 1,5 cases of type Ⅰ in group two, 2 cases of type Ⅰ and 3 cases of type Ⅱ b in group three, 2 cases of type Ⅰ and 2 cases of type Ⅱ b in group four, 5 cases of type Ⅱ b in group five and 5 cases of type Ⅲ in group six were noticed in the left testes. And in TICs of right testes, all cases showed TICs of type Ⅰ except 2 cases of type Ⅱ a in group six. In four torsion groups, the values for SER75 of the left side were 0. 084%, 0. 076%, 0.164% and 0.065%, while the right side were 0.255%, 0.410%, 0.586% and 0.302% (P ＜0.05). The values for SER120 in group three, five and six were 0.221% , 0.158% and 0.059% for the left side, and 0.405%,0.522% and 0.207% for the right side(P ＜0.05). The values for MSER in group three, five and six were 0.217% ,0.164% and 0.072% for the left side, and 0.405%, 0.586% and 0.302% for the right side(P ＜0.05). Conclusion DCE-MRI technique may be useful in the diagnosis of testicular torsion, which shows potential in the clinical application.

Objective:To evaluate the safety and efficacy of a dedicated neonatal-infant brain 0.35 T MRI system.Methods:A dual-center controlled clinical trial was conducted with single-arm objective performance criteria. From June to July 2020, sixty-six infants aged 0-12 (6.3±3.4) months were recruited from Children′s Hospital of Soochow University and the First People′s Hospital of Lianyungang prospectively. All infants underwent brain MRI with a dedicated neonatal-infant 0.35 T brain MRI system, using the dedicated two-channel transceiver head coil. MRI protocol included spin echo T 1WI, fast spin echo T 2WI, fluid attenuated inversion recovery, diffusion weighted imaging and 3D gradient echo sequence. MRI sequences were set with three orientations (axial, sagittal and coronal). Each case received at least two scanning planes and two scanning sequences. Five-point Likert scoring system was used to evaluate the image quality of acquired images, and the target value was set as at least 3 points per image. The temperature, heart rate and breathe of the infants were recorded before and after MRI; the acoustic noise of the MRI system was measured during the scanning process; and the adverse reactions were recorded if presented. Results:Five infants successfully completed their examination during non-sedated sleep in a single attempt, and 61 infants after sedation with chloral hydrate. Based on MRI-based five-point Likert scoring system, 41 cases achieved a score of 5, 21 cases with a score of 4 and 4 cases with a score of 3. Cases with score of 3 was due to movement of the infants during the scan, which resulted in motion related artifacts. The vital signs of all infants showed stable before and after imaging, with heart rate of (126.8±12.9) beats per minute, breathe of (38.2±6.8) times per minute. It was found that 47 cases showed no sign of temperature raise after brain MRI, 15 cases had less than 0.3 ℃ raise and 4 cases had 0.3 ℃ to 0.5 ℃ raise. The noise recorded during the scanning process was (57.5±1.8) dB(A). One case had mild diarrhea on the day of MR scan, and the symptoms disappeared on the second day without treatment; no adverse reactions were found for the rest subjects.Conclusion:Dedicated neonatal-infant 0.35 T brain MRI system allows data acquisition with high safety and excellent image quality, which has potentials in the clinical applications.

Objective To summarize the current situation of the implementation of the death case discussion system in county-level medical institutions and analyze the existing problems,to attempt to make suggestions for improvement.Methods Judgmental sampling method was used in this study.A self-made questionnaire was used to conduct field investigation on the im-plementation of the death case discussion system in 16 county-level medical institutions in Chongqing,and semi-structured inter-views were conducted with medical staff.Results All county-level medical institutions have established death case discussion system,but there are many differences in connotative quality.There are many problems in system implementation,such as unclear scope of death case discussion,formality,irregular discussion,poor quality of connotation and lack of systematic supervision.Conclusion As a core medical system,the death case discussion system is an important tool for medical quality management.The medical quality management and medical staff must place a high value on the significance of death case discussion.In order to enhance medical quality and ensure patient safety,we must adhere to the principles of openness and honesty,systematic criti-cism,non-recrimination and non-punishment to conduct death case discussion in time and standardize,keep a record of death case discussions and enhance supervision.

The overall health condition of patients significantly affects the diagnosis,treatment,and prognosis of endodontic diseases.A systemic consideration of the patient's overall health along with oral conditions holds the utmost importance in determining the necessity and feasibility of endodontic therapy,as well as selecting appropriate therapeutic approaches.This expert consensus is a collaborative effort by specialists from endodontics and clinical physicians across the nation based on the current clinical evidence,aiming to provide general guidance on clinical procedures,improve patient safety and enhance clinical outcomes of endodontic therapy in patients with compromised overall health.