Objective To study the establishment of rat model of asphyxia-cardiac arrest and efficacy of CPR in order to find the length of optimum time of asphyxia to cause injury.Methods One hundred and twenty-six male Sprague-Dawley rats were randomly (random number) divided into sham operation group and experimental groups.Cardiac arrest was induced by asphyxiation after intravenous injection of vecuronium bromide.The experimental groups were assigned into AP4 (four-minute asphyxia period),AP6 and AP8 subgroups in accordance with different lengths of time of asphyxia subjected to.In these groups,CPR,including pre-cordial compression and synchronized mechanical ventilation,was initiated 4,6 and 8 min after asphyxia-induced cardiac arrest,respectively.The successful ratio of resuscitation and hemodynamic variables were recorded.Brain water content,neural deficit scores (NDS),imaging changes on MR,pathological changes of brain tissue and neuronal apoptosis were evaluated at 1 d,3 d and 7 days after ROSC.All the data were analyzed by single-factor analysis of variance or Chi-square test.P ＜ 0.05 was considered statistically significant.Result The lowest NDS occurred at 1 d after ROSC,brain water content and imaging changes on MR were most obvious at 3 d after ROSC,while pathological changes of brain tissue and neuronal apoptosis increased and reached the peak at 7d after ROSC.The survival rates after 24 hours of AP4,AP6 and AP8 groups were 85％,75％ and 45％,respectively.The rate of ROSC and survival rate of AP8 group were significantly lower than those of other groups (P ＜0.01).The longer time of asphyxia the severer pathological changes of brain tissue,brain edema,neural deficit,and magnetic resonance imaging changes in all experimental groups.As compared to other groups,the brain damage index of AP8 group was most serious,while that of AP6 group was moderate.Conclusions The rat model following asphyxia-induced cardiac arrest and cardiopulmonary resuscitation was established successfully.From the evidence of survival rate and damage grade of brain tissue,asphyxia for 6 min may be the rational length of ischemic time in this model.

Polyacrylamide resin was synthesized via surface-initiated atom transfer radical polymerization ( SI-ATRP) method. Acrylic amide ( AM) was grafted onto the surface of the chloromethyl polystyrene resin via SI-ATRP in the CuBr/2, 2'-bipyridine ( Bpy) system as catalyst at room temperature. The compositions of polyacrylamide resin were determined by means of elementary analysis, FT-IR analysis and scanning electron microscopy ( SEM) . The adsorption properties, the parameters of kinetics and the thermodynamics of the resin were evaluated in details, respectively. As the results, adsorption capacity of 2,4-dichlorophenoxyacetic acid (2,4-D) increased with the initial concentrations of solution increasing at room temperature, and its highest adsorption capacity was 111. 0 mg/g with solution concentration of 8 mmol/L. Adsorption isotherm at room temperature was determined and modeled with Langmuir and Freundlich equations. The thermodynamic equilibrium functions were calculated to be ΔG<0,ΔH=268. 2 kJ/mol, ΔS>0, hence, the adsorption was spontaneous, endothermic and entropy increasing. The kinetics fitted the pseudo-second-order well. The polyacrylamide-chloromethyl polystyrene (PAM-CMCPS) resin was used for the adsorption of 2,4-D in orange sample, and good results were obtained.

Objective To observe the protection and distribution of bone marrow mesenchymal stem cells (MSCs) by distinct intravenous infusion time on renal ischemia reperfusion injury (IRI) in rats.Methods We used unilateral nephrectomy and contralateral vascular occlusion method to establish renal IRI model in rats.The experimental groups which received 2 × 106 MSCs infusion through the tail vein,were subsequently divided into 3 subgroups:2 h pre-reperfusion (PreOp,n =16),immediately after reperfusion (Op,n =16),6 h post-reperfusion (PostOp,n - 16).The control groups included sham operation group (n =16) and ischemia group (n =16).Chemotaxis of DAPI-labeled MSCs was detected 6 h after administration in the IR kidney.Renal function was detected at 6,24,and 48 h respectively after operation. Forty eight h after operation,the renal tissues were harvested to observe the pathological changes by HE staining and the tubular epithelial cell apoptosis via TUNEL assay.Results MSCs were found in the experimental groups after IR in the kidney,most in PostOp group.Twenty-four and 48 h after reperfusion,there was no significant difference in Cr and BUN between the experimental groups and sham operation group (P＞0.05),but the levels of Cr and BUN in the experimental groups were significantly lower than in the IR group (P＜ 0.05). As compared with IR group,the renal pathological injury was alleviated,the number of apoptotic cells was decreased in the experimental group,most significantly in PostOp group (P＜0.05).Conclusion MSCs can reduce the inflammatory response and inhibit renal tubular cell apoptosis in rat renal IRI.Post-reperfusion administration of MSCs leads to the best chemotaxis efficiency and protection.

Objective:To describe the characteristics of liver damage in severe coronavirus disease 2019 (COVID-19) patients in Sichuan area and the effect of antiviral drugs on liver function.Methods:The clinical data of severe COVID-19 patients admitted to Chengdu Public Health Clinical Medical Center from January 21 to February 24, 2020 were retrospectively collected, including demographic data, clinical manifestations and liver function changes within 1 week after admission to intensive care unit (ICU). The changes of liver function during the course of disease in severe COVID-19 patients were analyzed and summarized, and group analysis was performed.Results:A total of 30 COVID-19 patients with complete clinical data were enrolled. The incidence of severe COVID-19 in elderly men was higher (60.0%), with median age of 61 (47, 79) years old, and those aged 80 or above accounted for 23.3%. The severe COVID-19 patients mainly presented with respiratory symptoms such as fever (96.7%), cough (80.0%) and dyspnea (66.7%). The alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBil) and prothrombin time (PT) of 30 patients were increased to various degrees within 1 week after ICU admission, and albumin (ALB) was decreased. ① The patients were divided into two groups according to whether to take lopinavir/ritonavir (kaletra). It was shown that the incidence of liver dysfunction in patients taking kaletra was significantly higher than those who did not take kaletra (7-day abnormal rate of ALT was 54% vs. 33%, the abnormal rate of AST was 38% vs. 33%, the abnormal rate of TBil was 8% vs. 0%), but there were no statistical differences (all P > 0.05). ② The patients were divided into normal dose group (500 mg, twice a day, n = 19) and reduced dose group (250 mg, twice a day, n = 5) according to the dosage of kaletra. It was shown that patients taking low-dose kaletra had a smaller effect on liver function within 1 week after ICU admission than those receiving normal dosage, and ALB, TBil in the reduced dose group were significantly lower than those in the normal dose group on the 2nd day after ICU admission [ALB (g/L): 33.3±2.0 vs. 37.5±4.0, TBil (μmol/L): 6.3±3.3 vs. 11.3±4.8, both P < 0.05]. Conclusions:Severe COVID-19 patients in Sichuan area suffered obvious liver damage in the early course of the disease and have a slower recovery. It is important to pay attention to avoid using drugs that can aggravate liver damage while treating the disease. If there is no alternative drug, liver protection treatment should be considered appropriately.

【Objective】 To investigate the effectiveness of multilink real-time fluorescence quantitative PCR (qPCR) in the detection of common pathogens in transplantation. 【Methods】 The primers of the qPCR detection system were designed for 24 common infectious pathogens after clinical transplantation, and the standard plasmids of each pathogen were used to verify the qPCR reaction.After the primer probe effect and concentration of each pathogen reaction system in this experiment was optimized, the sensitivity, correlation coefficient (R2) and amplification efficiency (E) of qPCR method were analyzed and confirmed.Twenty-two samples from patients, who underwent liver and kidney transplantation in transplant ICU of Sichuan Provincial People′s Hospital, were used to verify the application of the detection system.The total nucleic acid of 100 μL was extracted from each individual and divided into two aliquots, which were detected by multi-link qPCR reaction system and analyzed by high-throughput sequencing method (NGS). At the same time, samples (2 mL each) were taken from the transplanted patients for microbial culture.The results of the three detection methods were compared, and the NGS method was taken as the gold standard to analyze the positive detection rate of the multi-link qPCR method and its difference with the culture method and NGS. 【Results】 The lower limit of qPCR detection for 24 pathogens in the established qPCR detection system was 10¹cp/μL(R²>0.99), with the positive rate of pathogens at 59.1% (13/22), showing significant difference versus microbial culture (18.2%, 4/22)(P<0.05), but not versus NGS (63.6%, 14/22)(P>0.05). Percentage of pathogens detected was as follows: human herpetic virus type 6 (HHV-6) 30.8% (4/13), cytomegalovirus (HCMV) 23.1% (3/13), Epstein-Barr virus (EBV) 23.1% (3/13), human parvovirus B19 15.4% (2/13), Haemophilus influenzae (Hin) 15.4% (2/13), Enterococcus faecium (EFM) 15.4% (2/13), Clostridium difficile 15.4% (2/13), Escherichia coli 7.7% (1/13), Stenotrophomonas maltophilia (Sma) 7.7% (1/13), Klebsiella pneumoniae (Kpn) 7.7% (1/13), Enterococcus faecalis (Efa) 7.7% (1/13) and Streptococcus pneumoniae (Spn) 7.7% (1/13). The consistency rate of pathogens detected by the three methods was 32% (7/22), among which the consistency rate of multi-link qPCR with NGS method was 59% (13/22), and multi-link qPCR with microbial culture was 41% (9/22). 【Conclusion】 Compared with the microbial culture, the multi-link qPCR method demonstrated high sensitivity, accurate quantification, short time and low cost for the detection of common pathogens in clinical transplantation.Multi-link qPCR combined with NGS and microbial culture is helpful to quickly predict the pathogen infection status of patients after transplantation.