Presenilin-1 Asp385 is Indispensable for Neurogenesis,Angiogenesisand β-amyloid Production
摘要: Objective:Presenilin(PS)is one of major causative genes of early onset familial Alzheimer's disease(FAD),which accounts for 95% of genetic factors. Presenilin-1(PS1)is considered as the catalytic subunit of theγ-secretase complex that cleaves type Ⅰ transmembrane proteins,such as amyloid precursor protein(APP),a protein closely related with AD. One conserved aspartate residue (Asp385)in PS1 is thought to constitute the active site of γ-secretase. In vitro,D385A mutation (the aspartate to alanine alteration)leads to the failure of PS1 endoproteolysis and abolishment ofγ-secretase activity. To further investigate the role of Asp385 residue in PS1 in vivo,we generated PS1 D385A knockin(KI)mice,in which an Asp385Ala(D385A)alteration was introduced in the genomic Psen1 locus. Method:The gene-editing method of Cre-LoxP has been used to generate PS1 D385A KI mice;southern blot has been used to detect the genomic DNA from both embryonic stem(ES)cells and mouse tails to confirm its genotype. Northern and western have been used to test the mRNA and protein levels of PS1. Morphology and the proliferation of neural progenitor cells of developing brains has been test by HE staining and BrdU immunohistochemistry. Angiogenesis has been test by both western and immunofluorescence to target the marker of vascular endothelial cells,CD31. In vitro γ-secretase assay has been used to test the activity of γ-secretase. Results:Homozygous D385A KI(KI/KI)mice display severe developmental deficits,including abnormal skeleton development,perinatal lethality,cerebral hemorrhages,enlarged lateral ventricle and massive loss of neural progenitor cells,which is identical to those of Psen1-null mice. D385A mutation dose not interrupt the level of Psen1 mRNA,but disrupt PS1 endoproteolysis. The N- and C-terminal fragments of PS1 are absent,and PS1 holoprotein accumulates(~18-fold)in KI/KI mice relative to the wild type(WT)controls. In addition,D385A mutation abolishesγ-secretase activity in the brain of D385A KI/KI mice,and the activity is significantly reduced in KI/+ mice. Furthermore,compared with WT mice,the protein level of CD31 is significantly increased in KI/+ mice within development and adulthood. In adult,KI/+ mice also show abnormal angiogenesis in both cortex and hippocampus, and cerebrovascular amyloid plaques have been detected in 10 month age. Conclusion:Collectively, these results demonstrate that the Asp385 of PS1 is indispensable for its function in maintaining normal development,neurogenesis,and γ-secretase activity. Furthermore,D385A mutation causes abnormal angiogenesis and amyloid plaques in vessels in adulthood.
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两种椎管内麻醉在剖宫产术中的应用比较
临床上剖宫产应用椎管内麻醉有多种不同的注药方式,我院就剖宫产椎管内麻醉两种注药方式进行了临床比较,现报告如下.
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热牙胶根管充填技术的应用体会
目的:探讨热牙胶根管充填的特点和方法.方法:选择牙髓病或根尖周病患者61例,且患牙未接受过根管治疗者,用机用镍钛器械ProTaper预备根管,采用热牙胶连续波垂直加压充填技术和高温牙胶热塑注射充填法相结合充填根管,拍摄X光片,明确根充情况.术后3个月和6个月进行复查,观查根管充填效果.结果:61例病例中,根充恰填率90%,根尖窦道2~3周愈合,X光片显示根充严密合适,咬合功能良好,术后3个月和6个月进行复查,X光片显示根尖周透射区缩小,骨质密度增加.结论:热牙胶根管充填操作简便,节省操作时间,根端密封性好,具有广阔的临床应用前景.
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听神经瘤显微手术中神经和血管的保护
听神经瘤是常见的颅内良性肿瘤之一,占桥脑小脑角肿瘤的80%,全切除肿瘤可终身治愈.随着显微外科技术的不断成熟,影像技术的发展,听神经瘤病人的预后有了明显的改善,其病死率降低[1],面神经的解剖保留率及对血管的保护亦不断提高[2].现将我院2000.1~2005.6月经显微手术切除的23例听神经瘤病例报道如下.
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开窍丸治疗缺血性中风64例疗效观察
缺血性中风是中老年人常见病,以发病率高、复中率高、致残率高而成为危害中老年人健康的第三大疾病.目前西医对此病的治疗无重大突破,我们在临床中在常规治疗的基础上加上口服开窍丸(本院制剂室生产),取得良好疗效,现论述如下.
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上消化道大量出血患者的观察及护理
上消化道出血是指屈氏韧带以上的消化道,包括食管、胃、十二指肠或胰胆等病变引起的出血,以及胃空肠吻合术后的空肠病变的出血.
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术后早期炎性肠梗阻的诊治
术后早期炎性肠梗阻一般发生在腹部手术后1~3周,系指因手术创伤或腹腔内炎症等导致肠壁水肿和渗出,形成一种机械性与动力性同时存在的肠梗阻[1].目前多主张非手术治疗,现将1999~2005年间收治的21例结合文献报道如下.
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山西省大同市男性不育患者弓形虫感染情况调查
目的:探讨男性不育患者弓形虫(TOX)感染的状况及感染后对男性生殖功能的影响.方法:用酶联免疫吸附试验(ELISA )法检测男性不育患者血中弓形虫循环抗原(CAg),IgG及IgM抗体.结果:100例男性不育患者血清中CAg阳性者13例(13%),TOX-IgM阳性者16例(16%);而100例生殖功能正常的男性血清中CAg阳性者仅为1例(1%), TOX-IgM阳性者3例(3%);两者间差异非常显著(P《0.01).两者TOX-IgG阳性者均为7例(7%).结论:TOX急性(早期)感染可能会影响男性生育能力,并导致男性不育.因此,男性也应注意避免感染弓形虫,防止导致不育的情况发生.
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凉血地黄汤配合熏洗治疗肛肠病举隅
凉血地黄汤出自清代祁坤所著<外科大成>,主治"痔疮肿痛出血".药用黄连、黄芩、升麻清热解毒;生地、地榆、槐角、荆芥凉血止血;赤芍,归尾活血;花粉清热生津;枳壳行气;甘草和中.全方共奏清热凉血之功.熏洗方(自拟方):红花15g、防风15g、川椒15g、五倍子15g、黄柏30g、银花30g、苦参30g、蝉衣10g.
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急性酒精中毒合并心脏损害180例临床分析
目的:探讨急性酒精中毒对心脏引起的损害.方法:选择368例急性酒精中毒患者,对其行心电图及心肌酶的动态观察.结果:368例急性酒精中毒患者中有180例发生不同程度的心肌损害包括心律失常、CK-MB增高、心电图呈ST-T改变甚至急性心肌梗死.结论:急性酒精中毒造成的心肌损害是普遍且可逆的.
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剖宫产术子宫切口撕裂48例分析
随着剖宫产率不断上升,其并发症也随之增加,子宫切口撕裂是手术中常见的并发症之一.造成切口撕裂的原因有很多,如麻醉效果、子宫下段的形成情况、术者的手法以及胎儿等因素,现结合48例临床资料对剖宫产术子宫切口撕裂原因进行分析并探讨其预防措施.