Matrix_assisted laser desorption ionization_time of flight tandem mass spectrometry ( MALDI_TOF/TOF MS) and electrospray ionization_quadrupole_time of flight mass spectrometry ( ESI_Q_TOF MS) were used to confirm the structure of cyclic lipopeptide daptomycin fastly. First, the relative molecular weight 1916. 7107 of daptomycin was measured by ESI with error 0. 0007. The sample’s doubly charged peak m/z 809. 848 was selected as precursor ion for ESI_MS/MS analysis, and the exocyclic amino acid sequence C9 H19 CO_Trp_Asn_Asp was successfully matched. Second, the experimental conditions of cleaving daptomycin by lithium hydroxide ( LiOH) were optimized and the ring_opened process was monitored by MALDI_TOF/TOF MS. After obtaining ring_opened product with purity of above 95%, the MS/MS measurements by MALDI and ESI were carried out. The b+and y+of ring_opened product were completely matched, which confirmed the amino acid sequence of daptomycin. Finally, ESI_MS/MS conditions of ring_opened product were further optimized to obtain more low mass fragment ions for analyzing the structure of fatty acid chain and the cleavage pattern of fat chain in mass spectrometry was proposed. The method was fast, convenient, accurate and reliable for identifying cyclic lipopeptide compounds.

Objective To evaluate the effect of curing achalasia by transabdominally Heller-Dor operation. Methods To summarize 33 cases of achalasia treated by transabdominally Heller-Dor procedure and visit them postoperatvely. 18 patients receive pre- and post-operativemanometry and 24-hour-pH monitoring. The parameters including reflux frequency 、the longest lasting-time of reflux 、the total time(min) of pH ＜4.0 and the percentage( % ) of time of pH ＜4.0 were recorded and compared using statistical mothods. Results Symptom was significantly improved in 32 patients after surgery, while 1 patient remained dysphasia as pre-operative. The LESP, the reflux frequency、the longest lasting-time of reflux 、the total time(min) of pH ＜ 4.0 and the percentage ( % ) of time of pH ＜ 4.0 also declined after operations ( P ＜ 0. 05 ). 30 patients were followed up,22 (73.3% ,22/30) were cured and 8 had mild sypmtom. Reflux did not detected in 3 cases( 16.7% ,3/18 ) with preoperative reflux. Conclusion Transabdominally Heller-Dor operation could dramadically alleviate the symptoms of patients with achalasia, moreover, it could especially prevent the postoperative-reflux, and with the advantages of simple operations, little traumas.

Choledochojejunostomy is a common surgical method for the treatment of organ diseases such as hepatobiliary, gastrointestinal and pancreatic diseases, but there are many complications related to the operation. Benign biliary-enteric anastomosis stricture (BBES) is the most common long-term complication after operation, which seriously affects the quality of life of patients. At present, bile duct reconstruction and endoscopic treatment are the main methods to deal with BBES, but there are some limitations. The new interventional therapy has the advantages of small trauma, good repeatability, high success rate and few complications. It has been applied in many medical centers. The main treatment methods include percutaneous transhepatic biliary balloon dilatation, percutaneous temporary stent placement, percutaneous transhepatic choledochoscopy, magnetic compression anastomosis and intrabiliary ablation. Up to now, there is no uniform standard for the choice of interventional therapy for BBES at home and abroad, so it is of great clinical significance to establish a standardized interventional therapy strategy.

The function of immune system degenerates in an aging-dependent manner and this results in immunosenescence. Human immune system includes two parts: genetic/innate immunity and adaptive immunity. The former is involved in monocytes, nature killer cells, and dendritic cells, the later is involved in acquired B and T lymphocytes. During the aging of immunity system, the both parts of immunity are damaged to some degree. Generally, innate immunity seems well-retained and the acquired immunity is degenerative seriously with aging. Immunocyte senescence is closely related to the elderly decreased ability to control infectious disease, cancer and to their generally poor response to vaccination. This review summarized the research progress on immunosenescence characteristics in aged phase.
Age Factors ; Aging ; immunology ; Antibody Formation ; immunology ; Cellular Senescence ; Humans ; Immunity, Cellular ; immunology ; Lymphocyte Activation

As an important means of lung protective strategy, prone position ventilation (PPV) which can effectively shorten the time of mechanical ventilation, significantly reduce the mortality of patients with acute respiratory distress syndrome (ARDS), and is suitable for popularization and application in the ICU. However, some studies show that prolonged prone position can significantly increase the incidence of Stress injury, making it difficult to implement PPV in the practical level. In order to achieve the goal of safe and effective prevention of skin Stress injury, and to promote the correct implementation of PPV, this paper review the methods of preventing Stress injury in patients with PPV.

Objective:To explore the relationships among perceived social constraints, social participation, as well as anxiety and depression in first stroke patients, and to further analyze the mediating effect of social participation on these variables.Methods:A total of 216 first stroke patients in the Department of Neurology of Affiliated Hospital of Qingdao University from April to December 2020 were recruited by convenience sampling and investigated by general information questionnaire, Social Constraints Scale (SCS), Chinese version of Impact on Participation and Autonomy Questionaire (IPA-C) and Hospital Anxiety and Depression Scale (HADS).Results:The total score of SCS, IPA-C, depression and anxiety were 33.49 ± 6.81, 43.42 ± 9.62, 8.05 ± 4.15 and 8.61 ± 2.59. Social constraints were positively correlated with social participation as well as anxiety ( r=0.644, 0.383, both P<0.05). Social constraints were positively correlated with social participation as well as depression ( r=0.482, 0.371, both P<0.05). The quality of social participation partially mediated the relationship between social constraints and anxiety (intermediary effect was 0.119), and also partially mediated the relationship between social constraints and depression (intermediary effect was 0.270). Conclusions:First stroke patients experience high level of social constraints, low quality of social participation and severe anxiety and depression. Social constraints can affect anxiety and depression through social participation. Medical staff should build a good environment to meet the needs of stroke patients of social participation, help patients to establish a correct psychological coping style, reduce patients' avoidance of social participation due to perceived constraints and exclusion, and thus promote the mental health of patients.

Objective To analyse the relationship between Fourier transform infrared （FTIR） spectrum ofrat's spleen tissue and postmortem interval （PMI） for PMI estimation using FTIR spectroscopy combinedwith data mining method. Methods Rats were sacrificed by cervical dislocation, and the cadavers were placed at 20 ℃. The FTIR spectrum data of rats' spleen tissues were taken and measured at different time points. After pretreatment, the data was analysed by data mining method. Results The absorption peak intensity of rat's spleen tissue spectrum changed with the PMI, while the absorption peak position was unchanged. The results of principal component analysis （PCA） showed that the cumulative contribution rate of the first three principal components was 96%. There was an obvious clustering tendency for the spectrum sample at each time point. The methods of partial least squares discriminant analysis （PLS- DA） and support vector machine classification （SVMC） effectively divided the spectrum samples with different PMI into four categories （0-24 h, 48-72 h, 96-120 h and 144-168 h）. The determination coefficient （R2） of the PMI estimation model established by PLS regression analysis was 0.96, and the root mean square error of calibration （RMSEC） and root mean square error of cross validation （RMSECV） were 9.90 h and 11.39 h respectively. In prediction set, the R2 was 0.97, and the root mean square error of prediction （RMSEP） was 10.49 h. Conclusion The FTIR spectrum of the rat's spleen tissue can be effectively analyzed qualitatively and quantitatively by the combination of FTIR spectroscopy and data mining method, and the classification and PLS regression models can be established for PMI estimation.

Objective To investigate the clinical therapeutic methods and their curative effects in recurrent ischemic angina for internal mammary artery resterosis after coronary artery bypass grafting (CABG).Methods We enrolled the patients who had recurrence of ischemic angina for restenosis of internal mammary artery graft after CABG as research subjects in the Affiliated Hospital of Yan'an University from January 2014 to January 2016.The 42 patients were divided into three groups according to the different treatment approaches for recurrence of ischemic angina:Group A (n=22)who received internal mammary artery interventional therapy;Group B (n=12)who received coronary artery bypass grafting treatment;and Group C (n=8)who received left subclavian artery proximal stent treatment.Then we compared the clinical therapeutic effects in the three groups.Results The success rate in Group C was 100%,which was the highest in the three groups,and the post-operative restenosis rate was 0.The hospitalization time was significantly shorter in Group A than in Group B (P＜0.05).However,the two groups did not significantly differ in mortality,success rate or restenosis rate (P＞0.05).Conclusion We should select the appropriate treatment according to the patient's specific situation for recurrent ischemic angina. Endovascular treatment has evident therapeutic effects,rapid postoperative recovery,and lower treatment risk, making it the preferred treatment when possible.

Objective To investigate the inhibitory effects of magnesium citrate(MgCit)on oxidative stress in chronic renal failure(CRF).Methods SD rats were divided into CRF model group,MgCit groups(375 and 750 mg/kg),normal control group,and MgCit control group(750 mg/kg).The morphology of mitochondria in thoracic artery vascular smooth muscle cells(VSMCs)was observed by transmission electron microscopy.The content of superoxide dismutase(SOD)and malonaldehyde(MDA)in rat aorta and plasma was detected by the kit.The VSMCs were divided into normal control group,CRF model group,and MgCit groups(1.5 and 3 mmol/L).The levels of superoxide anion(DHE)and apoptosis were quantitatively detected by flow cytometry.Results Compared with the control groups,the mitochondria were swollen and the cristae fractured or disappeared in the model group;MgCit intervention could reduce mitochondrial swelling,but not cristae fracture.In the model group,SOD level in aorta and plasma decreased(P＜0.05)while MDA level increased(P＜0.05).MgCit intervention could increase SOD in aorta and plasma,but decrease MDA level(P＜0.05).In the CRF environment,the DHE content of VSMCs and apoptosis in CRF model group increased(P＜0.05).MgCit intervention could decrease DHE content and inhibit apoptosis(P＜0.05).Conclusion MgCit inhibits oxidative stress levels in vivo and in vitro in CRF.

Objective To explore the association between visceral adiposity index(VAI)and nonalcoholic fatty liver disease(NAFLD)in lean population and the predictive value of VAI.Methods A total of 2 576 healthy subjects,body mass index(BMI)＜24 kg/m2,from The Second Affiliated Hospital of Xi'an Jiaotong University from June 2020 to May 2021 were randomly included and divided into lean NAFLD(n=213)and healthy control group(n=2 363).According to the VAI quartiles,they were divided into Q1-Q4 groups from low to high.The differences in biochemical parameters and the prevalence of NAFLD were compared among groups.The correlation between VAI and lean NAFLD was analyzed with restricted cubic spline(RCS),and the predictive value of VAI was explored by Logistic regression and receiver operating characteristic(ROC)curve.Results A total of 2 576 participants were included,and the prevalence of lean NAFLD was 8.3％(213 cases).The mean age,male ratio,BMI and waist circumference(WC)from group Q1 to group Q4 were significantly increased in a dose-response relationship(all P＜0.001).Compared with those in group Q1,systolic blood pressure,diastolic blood pressure,white blood cell count,hemoglobin concentration,alanine aminotransferase,aspartate aminotransferase,γ-glutamyl transpeptidase,alkaline phosphatase,total cholesterol,triglyceride,low-density lipoprotein cholesterol,blood uric acid,and fasting blood glucose levels in groups Q2 to Q4 were significantly increased,while direct bilirubin and high-density lipoprotein cholesterol levels were gradually decreased(both P＜0.001).The prevalence rate of NAFLD in groups Q1-Q4 was 0.6％,3.3％,7.0％and 22.2％,respectively(P＜0.001).RCS showed that the risk of NAFLD in lean population rose significantly with the increase of VAI(P＜0.001),and there was a nonlinear relationship between them(P for nonlinear＜0.001).Logistic regression showed that after adjusting other confounding factors,the risk of lean NAFLD in groups Q2,Q3 and Q4 was still 2.926 times(95％CI:0.971-8.811),3.435 times(95％CI:1.154-10.230),and 5.920 times(95％CI:1.873-18.719)that Q1 group.ROC curve showed that VAI had a good predictive value for lean NAFLD,with area under the curve of 0.815,critical value of 1.532,diagnostic sensitivity of 77.9％and specificity of 72.8％,which were better than BMI and WC.Conclusion VAI is significantly associated with the risk of NAFLD in lean population,and thus has a good predictive value.It can be used for early screening and diagnosis of lean NAFLD.