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Genome editing is a genetic engineering technique that uses site-directed cleavage activity of specific artificial nucleases and endogenous DNA damage repair activity to generate insertions, deletions or substitutions in the targeted genomic loci. As the accuracy and efficiency of genome editing is improving and the operation is simple, the application of genome editing is expanding. This article provides an overview of the three major genome editing technologies and genome editing types, and the regulatory frameworks for genome-edited products were summarized in the United States, the European Union, and other countries. At the same time, based on the Chinese safety management principles and systems for genetically modified organisms (GMOs), the authors proposed a regulatory framework for genome-edited products. Genome-edited products should first be classified according to whether containing exogenous genetic components such as Cas9 editing enzymes or not. They should be regulated as traditional genetically modified organisms if they do. Otherwise, the regulation of genome-edited products depends on targeted modifications.
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CRISPR-Cas Systems , Endonucleases , Gene Editing , Genome , Mutagenesis, Site-DirectedABSTRACT
Targeted replacement genome editing refers to DNA modification and engineering technology that could induce and achieve mutations of targeted gene replacement or knockin at a target gene or DNA region. In this review, the principles, implementation methods, factors that influence efficiency and accuracy, and applications of gene replacement editing were summarized and discussed. It provides the reference for gene functional characterization and genetic improvements through gene replacement strategies in higher plant especially crops.
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Objective To analyze CT and MRI characteristics of sellar cystic lesions.Methods Clinical and imaging data of 83 sellar cystic lesions were retrospectively analyzed.The location,size,number of the sac,thickness of the wall and some special signs,such as mural nodules,cavernous sinus invasion were observed.Results Totally 83 patients with sellar cystic lesions including cystic pituitary adenoma (n=33),craniopharyngioma (n=28),rathke cleft cyst (n-15),dermoid cyst (n =2),epidermoid cyst (n =2),arachnoid cyst (n =2) and pituitary abscess (n =1) were enrolled.The cystic pituitary adenoma and arachnoid cyst showed low signal on T1WI and high signal on T2WI.The signal of Rathke cleft cyst and craniopharyngioma displayed complex.Dermoid cysts,epidermoid cyst and pituitary abscess exhibited high signal on DWI.There were significant statistic differences of the size,number of the sac and the wall thickness among cystic pituitary adenomas,craniopharyngiomas and Rathke cleft cysts (all P＜0.05).Conclusion Observation of imaging features,including location,shape,signal intensity,characteristics of the capsule and some special signs can improve differential diagnosis of cystic lesion of sellar region.
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Objective To evaluate the role of mitochondrial permeability transition pore (mPTP) in hepatocytes in reduction of hepatic ischemia-reperfusion (I/R) injury by limb ischemic postconditioning in rats.Methods Forty-eight healthy male Sprague-Dawley rats,weighing 240-280 g,were randomly divided into 4 groups (n =12 each) using a random number table:sham operation group (group S);I/R group;limb ischemic postconditioning group (group LIPC);limb ischemic postconditioning and atractyloside group (group LIPC + APC).In I/R,LIPC and LIPC + APC groups,I/R injury was induced by 30 min occlusion of the hepatic artery and portal vein entering the left and middle lobes of the liver,followed by 120 min of reperfusion.The animals underwent 10 min of bilateral limb ischemia starting from 20 min after liver ischemia in group LIPC.In group LIPC+APC,the animals underwent 10 min of bilateral limb ischemia starting from 20 min after liver ischemia,and atractyloside 5 mg/kg was infused simultaneously via the penile vein.Blood samples were collected from inferior vena cava at the end of reperfusion to detect plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities.The rats were sacrificed,and the left lobe of the liver was removed to detect the degree of mPTP opening and to examine the ultrastructure of hepatocytes under electron microscope.Results Compared with group S,the plasma ALT and AST activities and degree of mPTP opening were significantly increased,and the damage to the ultrastructure of hepatocytes was obvious in the other three groups.Compared with group I/R,the plasma ALT and AST activities and degree of mPTP opening were significantly decreased,and the damage to the ultrastructure of hepatocytes was reduced in LIPC and LIPC + APC groups.Compared with group LIPC,the plasma ALT and AST activities and degree of mPTP opening were significantly increased in group LIPC+APC.Conclusion Limb ischemic postconditioning reduces hepatic I/R injury through inhibiting mPTP opening in hepatocytes of rats.
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To study the effect of Cu2+ and Zn2+ on amyloid-beta peptides (Abeta) aggregation, the morphology, size and cell toxicity of Abeta40 aggregates formed with the metal ions have been observed by the methods including ultraviolet spectroscopy, fluorescence spectroscopy and transmission electron microscopy. The results showed that Cu2+ and Zn2+ can accelerate Abeta40 aggregation, and both changed the morphology and size of Abeta40 aggregates. Zn2+ induced Abeta40 to form fibrous Abeta40 aggregates, while the amorphous and fibrous aggregates were produced by the interaction between Cu2+ and Abeta40. In addition, H2O2 was produced when Abeta40 reduced Cu2+. The relationship between metal ions and Abeta40 aggregates was analyzed, and the function of metal ions in Alzheimer's disease (AD) was illustrated in the research.
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Objective To investigate the clinical application and diagnostic value of three.dimensional and muhiplanar reconstruction of spiral CT in fracture of shoulder blade.Methods The image of three-dimensional and muhiplanar reconstruction of spiral CT in fracture of shoulder blade cases were analyzed retrospectively.Results The 54 bone fractures were found in 31 fracture of shoulder blade cases;the multiplanar reconstruction discovered 54 bone fractures,and could show the fracture line and small bone chips clearly,especially for the bone chips in articular cavity,but it could not display the three-dimension of bone fracture;three-dimensional reconstruction discovered 51 bone fractures,and could display the change about three-dimension of bone fracture,but it could not show the fracture line of the bone fracture with small and non-dislocated clearly.Conclusion Three-dimensional and multiplanar reconstruction of spiral CT were applied conjunctively can increase the accurate rate,and strengthen the sense of three-dimensional in fracture of shoulder blade;in addition,it also could show the articular corresponding relationship and surrounding soft tissue injury,and offer the considerable value for the establishment of therapeutic regimen.
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Objective To investigate the relationship of lacunar infarction (LI) and white matter lesion with cognitive impairment in patients with subcortical ischemic vascular disease (SIVD) Methods Fifty-three patients were diagnosed as SIVD according to the criteria of Erkinjuntti. The symptoms and signs were recorded by an interview and examination, and neuropsychological assessment and magnetic resonance imaging (MRI) were performed. A semi-automated MRI quantitative method was used to measure the volume of white matter hyperintensity (WMH) and the number of LI was counted. Correlation and the partial correlation analysis were performed to examine the relationship of general cognitive function with the volume of WMH and the number of LI. Results The pseudobulbar paralysis symptom and the upper motoneuron injury sign were the most common in these patients (18.9% and 37.7%). Correlation analysis showed that there was positive correlation between the volume of WMH and age (r = 0. 518, P < 0. 05), and there was negative correlcction between mini-metal state examination (MMSE) scures and the volume of WMH (r=-0.514, P<0. 05), After controlling confounding factors, only age was positively correlated with the volume of WMH (r=0. 400, P=0. 004). There were negative correlation between the number of LI, the volume of WMH and MMSE scores(r=-0. 456,-0. 514,-0. 385,-0. 382;all P<0. 05), and the years of education was positively correlated with MMSE scores (r= 0. 518, P< 0. 001). Conclusions Age may not be the main risk factor for cognitive impairment in patients with SIVD. The volume of WMH and the number of LI are independent risk factors for cognitive impairment in patients with SIVD. Patients with severer SIVD or more LI show poorer performance on cognitive function.
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Objective To understand the drug tolerance of Augmentin for Escherichia coli , Klebsiella pneumoniae spp and other pathogens Methods The MIC, MBC and bactericidal curves of Augmentin of 135 clinically isolated pathogenic bacteria were assayed The anti bacterial activity and clinical effect between Augmentin, Cefurxine, Ceftriaxone, Amoxicillin and Cefazolin were compared by MIC 50 , MIC 90 , MBC 50 , MBC 90 and modal number MIC,MBC Results Augmentin was better than the same kind of antibiotic without ? lactamase inhibitor It had a good effect for anti bacteria activity of extend spectrum ? lactamase (ESBLs) Escherichia coli and Klebsiella pneumoniae spp Conclusion Augmentin can be used for infection of ESBLs and other common pathogenic bacteria, since it has a good anti bacterial activity for most clinicaly isolated pathogenic bacteria and productive enzyme bacteria
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OBJECTIVE：Analyzing the epidemic of drug risistance bacteria with extend spectrum β-lactamase(ESBLs)in children's wards to cut off the transmitting pathway and prevent the outbreak of nosocomial infections in time.METHODS：Samples，including sputum，umbilical secretion，pus，pharyngeal swab，were collected from in-hospital child patients in Departments of Newborn，Respiratory Tract Diseases，Cardiology，Nephrology，Hematology，Pediatric Surgery and ICU，then bacterial cultures and drug susceptibility test were carried out.54 strains of ESBLs E.coli and Klebsiella pneumoniae were isolated and their plasmid profiles were analysed by agarose electrophoresis.RESULTS：The percentages of ESBLs in the above-mentioned departments were 46.3，12.9，5.6，12.9，5.6，11.1，5.6 respectively.In analysis，three types of profiles were found and strains with four types of the same profile concentrated in the Newborn Department.The others were dispersed.CONCLUSION：Nosocomial infections possibly occured in the Newborn Department to some extent.
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Objective To evaluate the epileptic focus localization value of MSI in patients with refractory epilepsy and encephalomalacia. Method MSI examination was proceeded in 11 patients with refractory epilepsy and encephalomalacia. Five of them were treated with gamma-knife; the others were treated with surgery. Results In the five patients treated with gamma-knife, the result was satisfied in 3 patients, one patient improved significantly, the other one useless. The distance between the encephalomalacia and the epileptic focus was 4cm in one patient; one patient′s encephalomalacia was located in right frontal-parietal lobe but the epileptic focus mainly located in right temporal lobe, only a little located around the encephalomalacia. Overall agreement among VEEG,ECoG and MEG (presence of concordant spikes with the same localization shown by three techniques) was obtained in three patients, the areas localized by ECoG were larger than VEEG and MSI in two patients. The localization was different in VEEG, MSI and ECoG in one patient, then he was given a resection of bilateral occipital epileptic focus. The results of patients treated with surgery were satisfied. Conclusion The MSI localization of epileptic focus in patients with refractory epilepsy and encephalomalacia is precise, and it can direct the advanced clinical treatment.
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The effects of Lipoid of Mujingzi〔LP,Fruits of vitex neguando L Var cannabifo- lia (Sieb et Zucc) Hand mazz〕 on Smooth muscles are reported. The results were as follows:① In the isolated perfused mice lung-bronchi, LP caused significant increase of perfusion medium dropping through the lung-trachea, and the effect of LP was dose-dependent; ACh (Acetyl-choline)-induced contraction of the isolated mice trachea smooth muscles could be relaxed by LP. ② When LP was given introperitoneally(100~ 300 mg?kg-1) into guinea pig, the incubationperiod of asthma induced by acetycholine together with histamine was prolonged.The optimum dilated effect of LP on smooth muscles of trachea in mice can be concluded as the results of synergistic effects by 4 compositions from LP (Oleic acid,Linoleic acid, Palmitic acid and Stearic acid).