BACKGROUND: With the fast development of computer technology,biomechanical study of cervical vertebra is not limited in animal or human corpses,because computer model can provide a more accurate model.OBJECTIVE: To develop a three-dimensional,finite element model of a human C2-7 based on previous studies,and to provide experimental data for the biomechanical study of the cervical spine.METHODS: A normal young 28-year-old male,without obvious cervical spondylosis history,was selected,and C-spine X-rays at posteroanterior,oblique,and over extension and over flexion position were performed to deplete cervical spondylosis.The CT scanning images were dealed with Software Mimics and Geomagic to obtain the finite element,and software ANSYS was used to study the response of the model.Under a 1.8 N·m segmenal movement and force displacement response were observed and compared with abroad experimental results.RESULTS AND CONCLUSION: The new finite element model was composed of six vertebrae(C2-7),five discs(C2/3-6/7)and main ligaments.The model consisted of solid elements with 23 348 nodes and 215 749 units.The results of the biomechanical study were better correlated with the available experimental data.It indicates that the finite element model of cervical spine at C2-7 can be used to imitate the biomechanical experiment of cervical spine.

Objective To explore the clinico-biological characteristics, treatment and prognosis of salivary duct carcinoma. Methods This study included 12 cases of salivary duct carcinoma treated in our hospital. Clinical data were retrospectively analyzed for patients admitted between April 1995 and October 2006. The clinical characteristics, histological features, imaging, therapy methods and prognosis were analyzed. Results Of 12 salivary duct carcinoma, there were 10 males, 2 females. The age of onset ranged from 53 to 73 year old and the average was 56 year old. Physical examination revealed a firm and unboundary mass accompanied by nerve infiltrating symptom. The histological appearance was characterized by solid cell nests with ductal structures and central comedonecrosis. Extensive resection and radical neck dissection was performed in 11 patients, postoperation radiation done in 10 patients and chemotherapy in 3 patients. One year survival rate was 83. 33% , that of 3 years was 41. 67% , and of 5 years was 25. 00% , the median survival time was 36 months. Conclusion Salivary duct carcinoma is a rare malignant salivary tumor and most patients are men. Regional extensive resection and postoperative radiation or chemotherapy are the mainstay of therapy. Lymph node metastases in level Ⅰ ,Ⅱ , Ⅲ are a common finding in patients with SDC and the prognosis is poor.

Objective: To evaluate the short-term effect of thrombus aspiration catheters combining tiroifban medication for myocardial tissue reperfusion recovery in patients with acute ST-elevation myocardial infarction (STEMI).
Methods: A total of 105 STEMI patients with percutaneous coronary intervention (PCI) in our hospital from 2011-05 to 2013-05 were studied, there were 73 male and 32 female with the mean age of (58.39 ± 10.37) years. The patients were randomly divided into 2 groups, Group A, the patients received thrombus aspiration catheters with intravenous tiroifban, n=53 and Group B, the patients received tiroifban and PCI, n=52. The basic clinical features, myocardial tissue perfusion level, major adverse cardiovascular events (MACE) at post operative and in-hospital period were recorded, the cardiac function was examined by echocardiography at 6 months after PCI in both groups.
Results: The basic clinical features were similar between 2 groups. The thrombolysis in myocardial infarction trial (TIMI) 3 lfow rate was higher in Group A than that in Group B (92.45% vs 55.77%), P=0.000. TIMI 2 and TIMI 0~1 lfow rates were lower in Group A than that in Group B (7.55%vs 26.92%), P=0.008 and (0%vs 17.31%), P=0.002. The adjusted TIMI frame was lower in Group A (27.26±5.50) vs (38.98±5.42), P<0.001. The echocardiography at 6 months after PCI indicated that Group A had higher LVEF than that in Group B (0.55±0.06) vs (0.47±0.06), P<0.001;lower left ventricular end diastolic diameter (50.77±5.45) vs (54.76±5.34), P<0.001;less angina and target vessel revascularization (16.98%vs 40.38%), P=0.008 and (9.43%vs 17.31%), P=0.008. The incidence of MI, acute heart failure, cardiac death and non-target vessel revascularization were similar between 2 groups, P>0.05.
Conclusion:Thrombus aspiration catheters combining tiroifban medication may obviously improve the myocardial tissue reperfusion and the short-term cardiac function in STEMI patients after PCI, it could reduce the incidence of no-relfow without increasing MACE.

Objective:To analyze the clinical characteristics that affect the early outcomes of the elderly patients with transient ischemic attack(TIA) and provide the guidance for the prediction of disease recurrence.Methods:From January 2016 to December 2019, 315 TIA patients over 60 years old based on the time-clinical definition who were admitted to the department of neurology in Beijing Shijitan Hospital were divided into recurrence cerebrovascular events group(RCVEs group) and non-recurrence cerebrovascular events group(non-RCVEs group) according to the recurrence at 1 month after onset. The clinical characteristics of the two groups were compared by Logsitic regression analysis.Results:There were 29 cases in the RCVEs group and 286 cases in the non-RCVEs group. Compared to the non-RCVEs group, patients in RCVEs group were more likely have higher prevalence of hypertension history(14/15, 83/203), moderate or severe intracranial artery stenosis(21/8, 132/154), carotid stenosis(22/7, 107/179), DWI positive, motor symptoms, carotid artery stenting and higher times of TIA episodes(2(2, 3), 2(1, 2)), fasting blood glucose and glycosylated hemoglobin levels(8.86(8.17, 9.56)mmol/L, 5.82(5.27, 6.33)mmol/L). Logistic regression analysis showed that patients in RCVEs group had a DWI positive( B=1.634, OR=5.124, 95% CI: 2.898-9.059, P=0.000) and higher prevalence of moderate to severe stenosis of carotid artery( B=0.572, OR=1.773, 95% CI: 1.050-2.993, P=0.032). Conclusion:DWI positive and moderate to severe carotid stenosis may influence the early poor prognosis in patients with TIA.

Traditional Chinese medicine (TCM) preparations are widely used for healthcare and clinical practice. So far, the methods commonly used for quality evaluation of TCM preparations mainly focused on chemical ingredients. The biological ingredient analysis of TCM preparations is also important because TCM preparations usually contain both plant and animal ingredients, which often include some mis-identified herbal materials, adulterants or even some biological con-taminants. For biological ingredient analysis, the efficiency of DNA extraction is an important fac-tor which might affect the accuracy and reliability of identification. The component complexity in TCM preparations is high, and DNA might be destroyed or degraded in different degrees after a series of processing procedures. Therefore, it is necessary to establish an effective protocol for DNA extraction from TCM preparations. In this study, we chose a classical TCM preparation, Liuwei Dihuang Wan (LDW), as an example to develop a TCM-specific DNA extraction method. An optimized cetyl trimethyl ammonium bromide (CTAB) method (TCM-CTAB) and three com-monly-used extraction kits were tested for extraction of DNA from LDW samples. Experimental results indicated that DNA with the highest purity and concentration was obtained by using TCM-CTAB. To further evaluate the different extraction methods, amplification of the second internal transcribed spacer (ITS2) and the chloroplast genome trnL intron was carried out.The results have shown that PCR amplification was successful only with template of DNA extracted by using TCM-CTAB. Moreover, we performed high-throughput 454 sequencing using DNA extracted by TCM-CTAB. Data analysis showed that 3-4 out of 6 prescribed species were detected from LDW samples, while up to 5 contaminating species were detected, suggesting TCM-CTAB method could facilitate follow-up DNA-based examination of TCM preparations.

PET/MR has been clinically applied in 2010 as an emerging and promising multimodal molecular imaging technology. This review includes 33 comparative studies on PET/MR and PET/CT since January 1, 2016, and the results of 15 literatures show that the diagnostic efficacy of PET/MR is better than that of PET/CT (including diagnostic accuracy and TNM staging). Only 11 articles have reported enhanced PET/MR, so the advantages of PET/MR can not be fully reflected.

Objective To investigate any protective effect of low-intensity pulsed ultrasound (LIPUS) and pioglitazone on chondrocytes in osteoarthritic patients using the pathway from peroxisome proliferator-activated γreceptor (PPARγ) to nuclear factor kappa B (NF-κB) to inducible nitric oxide synthase (iNOS).Methods Normal chondrocytes of 24 healthy adult New Zealand white rabbits were extracted and divided into a normal group,a lipopolysaccharide (LPS) group,a LIPUS group (LPS+LIPUS) and a pioglitazone group (LPS+pioglitazone),each of 6 using a random number table.Each group was given the intervention their names implies.The levels of tumor necrosis factor-α (TNF-α),leptin (LEP) and nitric oxide (NO) in the chondrocytes were detected using enzyme-linked immune sorbent assays.The expression of type Ⅱ collagen (COL2) in the chondrocytes of each groups was detected using immunocytochemistry and fluorescent staining.The mRNA and protein expressions of PPARγ,NF-κB and iNOS were detected using reverse transcription polymerase chain reactions and western blotting respectively.Results Compared with the LPS group,the average level of TNF-α,LEP and NO in the LIPUS and pioglitazone groups was significantly lower,with the levels in the pioglitazone group significantly lower than in the LIPUS group.Compared with the LPS group,COL2 expression in the LIPUS group was significantly greater.The mRNA and protein expressions of PPARγ in the chondrocytes in the LIPUS and pioglitazone groups were significantly higher than those in the LPS group.Compared with the LPS group,the mRNA and protein expressions of NF-κB and iNOS in the pioglitazone and LIPUS groups were significantly lower,with the pioglitazone group's levels significantly below those of the LIPUS group.Conclusion LIPUS and pioglitazone may promote anti-inflammatory action and COL2 synthesis in chondrocytes through the PPARγ/ NF-κB/iNOS pathway and play a protective role,at least in rabbits.

OBJECTIVETo establish a fluorescent polymerase chain reaction (F-PCR) method for detecting the coronavirus related to severe acute respiratory syndrome (SARS) and to evaluate its value for clinical application.

METHODSThe primers and the fluorescence-labeled probe were designed and synthesized according to the published sequence of the SARS-associated coronavirus genes. A F-PCR diagnosis kit for detecting the coronavirus was developed, and 115 clinical nasopharyngeal gargling liquid samples were tested.

RESULTSThe sequence of PCR amplified products completely matched the related sequence of the SARS-associated coronavirus genome. Forty-nine out of 67 samples from identified SARS patients and 8 of 18 samples from persons having close contact with SARS patients showed positive results. All 30 samples from healthy controls were negative.

CONCLUSIONThe F-PCR method established may be a rapid, accurate and efficient way for screening and for the early diagnosis of SARS patients.

Objective:To analyze the lipid composition of coronary atherosclerotic plaques and explore the mechanism of its influence on the medium and long-term efficacy of coronary endarterectomy(CE).Methods:From January 2018 to December 2019, a total of 50 patients with diffuse coronary artery disease(DCAD)and hyperlipidemia in Beijing Anzhen Hospital were enrolled to undergo coronary artery bypass grafting combined with anterior descending CE. After the informed consent was signed before the operation, the coronary endarterectomy plaque tissue and blood plasma samples were taken during the operation. Patients were further examined by coronary atherosclerosis T1-weighted characterization(CATCH) and power domain non-orthogonal multiple access(NOMA)postoperatively to analyze middle and long-term coronary restenosis risks. They were divided into high-risk group(restenosis rate >25%, study group) and matched low-risk group(control group). Lipid and molecular biological analysis were performed in the two groups to detect the tissue and cytochrome P450 3A4 enzyme(CYP3A4) content of plaque samples.Results:8 patients were enrolled in each group. The lipid analysis showed that and tissue samples from patients in the study group had a significantly higher level of 4α- Hydroxycholesterol(4α-OHC)as compared to the control group(0.050 μmol/g vs. 0.016 μmol/g, P<0.05). Further, 12 months after the operation, CATCH results showed that the patency rate of the control group was better than that of the study group[coronary artery stenosis rate(9.01±1.9)% vs.(22. 31±2.3)%, P<0.05]. Comparison of CYP3A4 content showed that: the CYP3A4 in blood plasma for the study group was higher than that in the control group[immediate(0.88±0.05)ng/ml vs.(0. 45±0.03) ng/ml and(2. 08± 0.40) ng/ml vs.(1. 58± 0.16)ng/ml, P<0.05]. Conclusion:High expression of 4 α- OHC may accelerate atherosclerosis(AS) after CE and cause restenosis in the middle and long term; It was also confirmed that 4 α- OHC is a biomarker of CYP3A4, which suggests for further investigation of the mechanism of progression after CE.

Objective? To explore the knowledge level of hospital infection control in nurses of key clinical departments and to provide a reference for providing more targeted hospital infection training. Methods? The nurses of key clinical departments in Beijing Tiantan Hospital, Capital Medical University in December 2017 were selected by convenient sampling and investigated with the self-designed hospital infection knowledge questionnaire. t test and variance analysis were used to compare the knowledge level of hospital infection between nurses with different characteristics. Results? The score for hospital infection knowledge in the 872 nurses from key clinical departments was (20.34±3.21), and the score in 61.58% of them was ≥20;the highest scoring rate was found in hand hygiene, while the lowest scoring rate was found in infectious disease knowledge and diagnosis; and there were statistical differences in knowledge level of hospital infection between nurses from different departments and with different professional title, educational background and students to teach or not (F/t=4.39, -3.69, -3.13, 5.24; P＜0.05). Conclusions? The knowledge level of hospital infection control in nurses of key clinical departments stands at a low level. Targeted training should be provided to nurses with different characteristics. Multiple management measures need to be taken to strengthen the supervision and monitoring over these departments, enhance the infection control ability in nurses from key departments, and prevent hospital infection.