It is the main method for amplifying the specific gene to use the nucleic acid amplification system to accomplish polymerase chain reaction (PCR). The temperature retard between heat source and sample exists in the heating and cooling progresses of most nucleic acid amplification system. The retard would result in the problem that the sample would take a long time to reach the set temperature and the problem would reduce the speed of integrate reaction. Non-specific products would be created in the process of amplification when the sample cannot reach the set temperature within a certainly time and the amplified efficiency would be reduced. A miniaturization nucleic acid amplification system heated by air was designed in this study according to the principle of air-heated nucleic acid amplification system and the characteristics of the PCR instrument Smart-cycler. The heat transfer process was analyzed and the heat transfer time was calculated. The actual temperature was measured in real time, and the temperature curves were fitted. The heating time was chosen by analysis results and data fitting and the air temperature was changed, while the sample temperature was recorded. The retard between sample and air was optimized by choosing the best curve of sample temperature. The temperature retard between sample and air was reduced sharply and the required time of integrate progress is shortened to 50%. We confirmed from the amplification experiment of Listeria monocytogenes that the improved system could complete 3 cycles within 4 minutes, and the amplification effect was good. The amplification speed and effect could be improved effectively by optimizing the delay between sample and air.
ObjectiveTo explore the effectiveness of thoracic endovascular aortic repair (TEVAR) for blunt thoracic aortic injury (BTAI) with hostile stent-graft proximal landing zone. MethodsA retrospective analysis was made on the clinical data of 13 patients with BTAI with hostile stent-graft proximal landing zone treated by TEVAR between December 2007 and December 2014. There were 10 males and 3 females with the mean age of 44 years (range, 24-64 years). The imaging examination indicated Stanford type B aortic dissection in 7 cases, pseudoaneurysm in 3 cases, aneurysm in 1 case, and penetrating ulcer in 2 cases. According to the partition method of thoracic aortic lesion by Mitchell, 8 cases underwent stent-graft with left subclavian artery (LSA) coverage, 3 underwent chimney stents for LSA, and 2 for left common carotid artery (LCCA). In 2 cases receiving chimney TEVAR involving LCCA, one underwent steel coils at the proximal segment of LSA to avoid type II endoleak and the other underwent in situ fenestration for endovascular reconstruction of LSA. ResultsAll TEVAR procedures were successfully performed. The mean operation time was 1.8 hours (range, 1-3 hours); the mean intraoperative blood loss was 120 mL (range, 30-200 mL); and the mean hospitalization time was 15 days (range, 7-37 days). No perioperative death and paraplegia occurred. The patients were followed up 3-30 months (mean, 18 months). Type I endoleak occurred in 1 case during operation and spontaneously healed within 6 months. Hematoma at brachial puncture site with median nerve compression symptoms occurred in 1 case at 3 weeks after operation; ultrasound examination showed brachial artery pseudoaneurysm and thrombosis, and satisfactory recovery was obtained after pseudoaneurysmectomy. No obvious chest pain, shortness of breath, left upper limbs weakness, numbness, and dizziness symptoms were observed. Imaging examination revealed that stentgraft and branched stent remained in stable condition. Meanwhile the blood flow was unobstructed. No lesions expanded and ruptured. No new death, bacterial infection, or other serious complications occurred. ConclusionAccording to Mitchell method, individualized plan may be the key to a promising result. More patients and further follow-up need to be included, studied, and observed.
ObjectiveTo investigate whether Akt1 gene transfection mediated by recombinant lentivirus (LVs) in the bone marrow mesenchymal stem cells (BMSCs) could enhance the ability of hypoxia tolerance so as to provide a theoretical basis for improving the effectiveness of stem cells transplantation. MethodLVs was used as transfection vector, enhanced green fluorescent protein (EGFP) was used as markers to construct the pLVX-EGFP-3FLAG virus vector carrying the Akt1 gene. The 3rd generation BMSCs from 3-5 weeks old Sprague Dawley rats were transfected with pLVX-EGFP virus solution as group B and with pLVX-EGFP-3FLAG virus solution as group C; and untransfected BMSCs served as control group (group A). At 2-3 days after transfection, the expression of green fluorescent was observed by fluorescence microscope; and at 48 hours after transfection, Western blot method was used to detect the expression of Akt1 protein in groups B and C. BMSCs of groups B and C were given hypoxia intervention with 94%N2, 1%O2, and 5%CO2 for 0, 3, 6, 9, and 12 hours (group B1 and group C1) . The flow cytometry was used to analyze the cell apoptosis rate and cell death rate, and the MTT method to analyze the cell proliferation, and Western blot to detect the expression of apoptosis related gene Caspase-3. ResultsAfter transfection, obvious green fluorescence was observed in BMSCs under fluorescence microscopy in groups B and C, the transfection efficiency was about 60%. Akt1 expression of group C was significantly higher than that of group B (t=17.525, P=0.013) . The apoptosis rate and cell death rate of group B1 increased gradually with time, and difference was significant (P<0.05) . In group C1, the apoptosis rate and cell death rate decreased temporarily at 3 hours after hypoxia intervention, then increased gradually, and difference was significant (P<0.05) . The apoptosis rate and cell death rate of group C1 were significantly lower than those of group B1 at each time point (P<0.05) except at 0 hour. MTT assay showed that absorbance (A) values of groups B and C were significantly higher than those of groups B1 and C1 at each time point (P<0.05) ; the A value of group B was significantly lower than that of group C at each time point (P<0.05) . The A value of group B1 was significantly lower than that of group C1 at 6, 9, and 12 hours after hypoxia intervention (P<0.05) . Western blot results showed that the Caspase-3 expression of group C1 significantly reduced when compared with group B1 at each time point (P<0.05) . ConclusionsAkt1 gene transfection mediated by recombinant LVs could significantly improve hypoxia tolerance of BMSCs by inhibiting the apoptosis, which could provide new ideas for improving the effectiveness of stem cells transplantation.
Artifacts produced by chest compression during cardiopulmonary resuscitation (CPR) seriously affect the reliability of shockable rhythm detection algorithms. In this paper, we proposed an adaptive CPR artifacts elimination algorithm without needing any reference channels. The clean electrocardiogram (ECG) signals can be extracted from the corrupted ECG signals by incorporating empirical mode decomposition (EMD) and independent component analysis (ICA). For evaluating the performance of the proposed algorithm, a back propagation neural network was constructed to implement the shockable rhythm detection. A total of 1 484 corrupted ECG samples collected from pigs were included in the analysis. The results of the experiments indicated that this method would greatly reduce the effects of the CPR artifacts and thereby increase the accuracy of the shockable rhythm detection algorithm.
【Abstract】 Objective To survey the prevalence and risk factors of chronic obstructive pulmonary disease ( COPD) , and establish database for community intervention of COPD.Methods A cluster-randomsampling survey was carried out. The population aged over 40 years old in eight communities of Chengdu were investigated from August 2007 to August 2009 using the standard protocol and questionnaire. The spirometry was performed for each participant. Results A total of 4315 residents were enrolled in this survey and 3687 case reports were analyzed, including 1529 males and 2148 females, with an average age of 60. 35 ±13. 21 years old. Total prevalence of COPD was 9. 6% . The prevalence of COPD in the males was significantly higher than that in the females ( 14. 0% vs. 6. 4%, P lt;0. 01) . The prevalence of COPD increased with the age. The major risk factors were cigarettes smoking ( OR = 3. 012, 95% CI 2. 390-3. 797, P lt; 0. 01) and indoor cooking smoking ( OR = 2. 546, 95% CI 1. 734-3. 425, P lt; 0. 01) . Conclusion The prevalence of COPD in Chengdu city is significantly higher than average level of the whole country, which warrant moreattention to better prevention and treatment of COPD in communities.