强力霉素调控小NEIA激活基因阻遏子表达NIH3T3细胞系的建立

背景：前期研究发现，E1A激活基因阻遏子蛋白调控人血管平滑肌细胞的增殖及表型转化，但其表达调控细胞增殖、分化、凋亡的量效关系有待深入探讨。目的：建立强力霉素调控小鼠E1A激活基因阻遏子表达的NIH3T3细胞系，拟为定量观察E1A激活基因阻遏子的生物学功能提供研究基础。设计、时间及地点：对比观察实验，于2006—05／2008—03在沈阳军区总医院全军心血管病研究所实验室完成。材料：强力霉素调控基因表达系统，3T3细胞系。方法：通过反转录一聚合酶链反应方法获得小鼠E1A激活基因阻遏子（mCREG）cDNA序列；将mCREGcDNA序列亚克隆入pRey—TRE载体中，构建强力霉素调控E1A激活基因阻遏子表达pRev—TRE—mCREG载体；分别经G418（新霉素）及潮霉素筛选表达pRev-Tet—On、pRev—TRE—mCREG的NIH3T3细胞克隆；反转录聚合酶链反应鉴定转染细胞克隆中抗性基因和插入基因的表达。主要观察指标：Western blotting检测不同浓度的强力霉素诱导后NIH3T3细胞中mCREG的表达。结果：成功构建了强力霉素可调控表达的pRev—TRE—mCREG重组载体；筛选出稳定表达双抗性基因的NIH3T3，mCREG细胞克隆；反转录-聚合酶链反应检测证实细胞克隆中G418及插入基因表达均为阳性；Western blotting检测发现随强力霉素诱导剂量的增加（O，O．01，0．1，1mg／L），NIH3T3．mCREG细胞中mCREG表达呈剂量依赖性增加。结论：成功建立强力霉素调控E1A激活基因阻遏子表达的小鼠NIH3T3细胞系。     

E1A激活基因细胞阻遏子蛋白在人脐静脉内皮细胞凋亡中的作用

背景:研究内皮细胞凋亡的机制及其与动脉硬化形成的关系将为动脉粥样硬化的防治提供新的思路.而E1A激活基因的细胞阻遏子蛋白在内皮细胞凋亡中的作用,目前尚未见报道.目的:探讨E1A激活基因的细胞阻遏子蛋白在去血清诱导的人脐静脉内皮细胞凋亡中的作用及其调控机制.时间及地点:实验于2007-10/2008-12在解放军沈阳军区总医院全军心血管病研究所实验室完成.材料:人脐静脉内皮细胞,Phoenix amphotropic 293细胞,pLNCX-CREG和pLNCX-GFP反转录病毒真核表达载体.方法:采用持续去血清培养的方法诱导内皮细胞凋亡,用TUNEL染色和Western blot检测去血清饥饿24,48,72 h后各实验组细胞中cleave-caspase3表达;用pLNCX-CREG和pLNCX-GFP反转录病毒真核表达载体转染人脐静脉内皮细胞,并筛选稳定表达的细胞克隆;应用Western blot检测E1A激活基因的细胞阻遏子蛋白的表达,并进一步应用流式双荧光染色分析E1A激活基因的细胞阻遏子蛋白过表达在去血清诱导的人脐静脉内皮细胞凋亡中的作用.主要观察指标:cleave-caspase3表达量,人脐静脉内皮细胞凋亡率.结果:成功构建了E1A激活基因细胞阻遏子过表达的人脐静脉内皮细胞模型,证实内皮细胞E1A激活基因细胞阻遏子的表达随凋亡的增加而增加,E1A激活基因细胞阻遏子过表达的人脐静脉内皮细胞去血清饥饿后凋亡较对照组明显减少.结论:E1A激活基因细胞阻遏子过表达抑制了去血清诱导的人脐静脉内皮细胞凋亡,机制可能与调控P13K蛋白表达有关.     

小鼠E1A激活基因阻遏子RNA干扰表达载体的构建

背景：血管平滑肌的增殖是动脉粥样硬化及支架内再狭窄发生的重要机制，小鼠E1A激活基因阻遏子（cellular repressor of E1A-stimulatedgenes，CREG）可以抑制血管平滑肌的增殖，成为心血管领域新的治疗靶点。目的：构建小鼠CREG小分子RNA干扰真核表达载体，下调小鼠细胞中cREG基因的表达。设计、时间及地点：观察性实验，于2007-04／10在解放军沈阳军区总医院心血管研究所完成。材料：小鼠成纤维母细胞系（NIH3T3）由美国新泽西州Robert Wood Johnson医学院病理实验科李少华教授馈赠。方法：应用RNA干扰在线设计工具设计4对可与小鼠CREG基因cDNA结合的短发夹RNA。通过化学合成法合成并克隆至pEN_mHlc载体中，与目的载体pDS_hpEY进行LR重组得到4种表达不同shCREG片段的表达载体pDS_shCREGs。应用Lipofectamine^TM 2000将pDS_shCREGs转染至小鼠NIH3T3细胞，G418筛选获得稳定转染的细胞克隆。主要观察指标：应用反转录聚合酶链反应和蛋白免疫印迹分别检测cREG的沉默效率。结果：经酶切和DNA测序证实，4种重组pDS_shCREG载体中插入片段的序列正确。反转录-聚合酶链反应和蛋白免疫印迹证实，4种稳定转染细胞中的CREG表达水平均有不同程度的下降，稳定转染pDS-shCREGl的细胞克隆中CREG基因mRNA和蛋白表达分别降低了87％和70％。结论：成功构建小鼠CREG基因真核干扰表达载体，使体外培养NIH3T3细胞中CREG蛋白表达明显降低。     

人骨形成蛋白2真核表达载体的构建和体外表达

背景：骨形态发生蛋白2（bone morphogenetic protein2，BMP-2）是已知的所有生长因子中对骨的形成作用最强的生长因子，被认为是最具有前途的骨诱导物质。目的：构建人骨形成蛋白2真核表达载体并观察其体外表达情况。设计、时间及地点：自身对照实验，于2005-07／2006-05在华中科技大学同济医学院分子生物中心实验室完成。材料：pcDNA3．1（＋）载体由华中科技大学同济医学院左石博士惠赠；成骨肉瘤组织由华中科技大学同济医学院附属协和医院骨科提供。方法：从人成骨肉瘤细胞中提取细胞总RNA，利用反转录．聚合酶链反应方法扩增获得人BMP-2基因cDNA，将基因片断重组到pGEM-T质粒中构建pGEM．T-hBMP-2重组质粒载体，转化到大肠杆菌DH5n后筛选阳性克隆，利用限制性酶切和DNA序列分析鉴定重组质粒。分别用RcoRI和NotI双酶切pGEM-T-hBMP-2质粒和pcDNA3．1真核表达载体，将克隆载体中人骨形成蛋白2基因重组到pcDNA3．1真核表达载体，提取质粒作酶切电泳、聚合酶链反应鉴定及DNA测序后，用脂质体体外转染小鼠骨髓基质细胞，反转录-聚合酶链反应检测BMP．2的表达。主要观察指标：①人骨肉瘤细胞总RNA反转录-聚合酶链反应结果。②重组质粒pGEM．T-hBMP-2和pcDNA3．1-hBMP-2的构建和酶切鉴定。③BMP-2在小鼠骨髓基质细胞内的表达。结果：人骨肉瘤细胞总RNA经反转录-聚合酶链反应扩增后，获得1．2kb条带。经酶切电泳、聚合酶链反应鉴定及DNA测序证实实验成功克隆BMP-2基因，重组质粒pcDNA3．1-hBMP-2构建正确；该重组质粒能在体外培养的小鼠骨髓基质细胞中有效表达BMP-2。 结论：实验成功克隆人骨形成蛋白2基因并构建了此基因的真核表达载体。     

小鼠Wnt-3a基因真核表达载体的构建及其在cos-7细胞中的表达

目的:克隆小鼠胚脑中Wnt-3a基因片段,构建pSecTag2／Hygro B-Wnt3a 真核表达载体,观察其在cos-7细胞中的表达,为基因治疗脊髓损伤提供实验依据。方法:实验于2004-09／2005-03在安徽医科大学分子生物学实验室完成。选取清洁级孕13．5 d的KM小鼠1只,脱颈处死,冰冷条件下迅速取出胚鼠,解剖显微镜下剥离胚脑,在无RNA酶污染的条件下迅速提取胚脑总RNA。利用反转录聚合酶链方法扩增小鼠胚脑Wnt-3a基因片段,将该基因片段克隆入T载体,聚合酶链反应法筛选并测序,双酶切后构建重组真核表达载体pSecTag2／Hygro B-Wnt3a。转染并筛选稳定表达的cos-7细胞,Western blot鉴定重组Wnt-3a蛋白的表达。结果:①反转录聚合酶链反应获得目的基因小鼠Wnt-3a cDNA:自胚鼠脑组织总RNA经反转录聚合酶链反应扩增后,凝胶电泳可见约1．1kb的特异性扩增片段,与预期获得产物大小相符。②pMD18-T/Wnt3a克隆质粒聚合酶链反应初步筛选与测序:测序报告所克隆的Wnt-3a为1 058 bp,通过Blast同源性分析,与GeneBank收录的序列一致,克隆小鼠Wnt-3a 基因获得成功。③真核表达载体pSecTag2／Hygro B-Wnt3a的双酶切及测序:随机挑选10个克隆,聚合酶链反应扩增筛选出阳性克隆5个,经 XhoⅠ和HindⅢ双酶切鉴定、测序及。Blast分析鉴定重组质粒构建成功。④Western Blot鉴定重组小鼠Wnt-3a蛋白在cos-7细胞中的表达:脂质体转染cos-7后48 h,Western Blot鉴定出在细胞内存在Wnt-3a蛋白的表达,转染pSecTag2／Hygro B-Wnt3a的cos-7细胞裂解液在45KD处出现阳性条带,而培养上清中未能检测到蛋白的表达。结论:小鼠胚脑Wnt-3a基因的真核表达载体pSecTag2／Hygro B-Wnt3a 构建成功,转染cos-7细胞后能够表达重组Wnt-3a蛋白。     

小鼠Wnt-3a基因真核表达载体的构建及其在cos-7细胞中的表达

目的：克隆小鼠胚脑中Wnt-3a基因片段，构建pSecTag2／Hygrn B—Wnt3a真核表达载体，观察其在cos-7细胞中的表达，为基因治疗脊髓损伤提供实验依据。方法：实验于2004-09／2005-03在安徽医科大学分子生物学实验室完成。选取清洁级孕13．5d的KM小鼠1只，脱颈处死，冰冷条件下迅速取出胚鼠，解剖显微镜下剥离胚脑，在无RNA酶污染的条件下迅速提取胚脑总RNA。利用反转录聚合酶链方法扩增小鼠胚脑Wnt-3a基因片段，将该基因片段克隆入T载体，聚合酶链反应法筛选并测序，双酶切后构建重组真核表达载体pSecTag2／Hygro B—Wnt3a。转染并筛选稳定表达的COS-7细胞，Western blot鉴定重组Wnt-3a蛋白的表达。结果：①反转录聚合酶链反应获得目的基因小鼠Wnt-3a cDNA：自胚鼠脑组织总RNA经反转录聚合酶链反应扩增后，凝胶电泳可见约1．1kh的特异性扩增片段，与预期获得产物大小相符。②pMD18-T／Wnt3a克隆质粒聚合酶链反应初步筛选与测序：测序报告所克隆的Wnt-3a为1058bp．通过Blast同源性分析，与GeneBank收录的序列一致，克隆小鼠Wnt-3a基因获得成功。③真核表达载体pSecTag2／Hygro B—Wnt3a的双酶切及测序：随机挑选10个克隆，聚合酶链反应扩增筛选出阳性克隆5个。经XhoⅠ和HindⅢ双酶切鉴定、测序及Blast分析鉴定重组质粒构建成功。④Western Blot鉴定重组小鼠Wnt-3a蛋白在cos-7细胞中的表达：脂质体转染cos-7后48h，Western Blot鉴定出在细胞内存在Wnt-3a蛋白的表达，转染pSecTag2／Hygro B—Wnt3a的COS-7细胞裂解液在45KD处出现阳性条带，而培养上清中未能检测到蛋白的表达。结论：小鼠胚脑Wnt-3a基因的真核表达载体pSecTag2／Hygro B—Wnt3a构建成功，转染COS-7细胞后能够表达重组Wnt-3a蛋白。     

E1A激活基因阻遏子蛋白对抗人脐静脉血管内皮细胞的凋亡

背景：前期研究显示,E1A激活基因阻遏子能够通过抑制动脉平滑肌细胞的凋亡对抗动脉粥样硬化。目的：进一步阐明E1A激活基因阻遏子在内皮细胞凋亡中的作用。方法：通过去血清方法诱导体外培养的人脐静脉内皮细胞凋亡,然后进行TUNEL和caspase-3的活性检测。结果与结论：伴随着E1A激活基因阻遏子的表达下降,内皮细胞的凋亡增多。功能获得和功能缺失分析显示：E1A激活基因阻遏子过表达后能够明显抑制内皮细胞的凋亡,而E1A激活基因阻遏子表达减少可以明显增加诱导内皮细胞的凋亡。进一步应用Western blot分析显示：E1A激活基因阻遏子对于内皮细胞凋亡的保护作用主要通过激活PI3K/AKT信号通路介导。提示E1A激活基因阻遏子对抗去血清诱导的内皮细胞凋亡中具有重要的作用。并且,E1A激活基因阻遏子抑制的内皮细胞凋亡可能通过PI3K/AKT信号转导通路。     

人可溶性血管内皮生长因子受体1基因克隆及真核表达载体的构建

背景;血管内皮生长因子在肿痛新生血管的形成中发挥着关键的作用,可溶性血管内皮生长因子受体1能竞争性地抑制血管内皮生长因子诱导新生血管形成的生物学功能.目的:克降人可溶性血管内皮生长因子受体基因1,尝试构建可溶性血管内皮牛长因子受体1基因的真核表达载体.设计、时间及地点:基因表达载体构建实验,于2006-1012007-11在中山大学附属第一医院外科实验室完成.材料:人脐静脉内皮细胞、pMD-18T载体及pcDNA3载体.方法:提取人脐静脉内皮细胞总RNA,使用反转录一聚合酶链反应的方法扩增获得到可溶性血管内皮生长因子受体1基因cDNA,并将其克隆至pMD-18T载体中,经酶切及测序证实.然后应用聚合酶链反应的方法从pMD-18T可溶性血管内皮生长因子受体1重组载体中克隆可溶性血管内皮生长因子受体1基因,再将其定向亚克降至真核表达载体pcDNA3中,构建真核表达重组体pcDNA3-可溶性血管内皮生长因子受体1,提取质粒进行双酶切、聚合酶链反应及测序鉴定.主要观察指标:可溶性血管内皮生长因子受体1基因反转录一聚合酶链反应情况及pcDNA3-可溶性血管内皮生长因子受体1真核重组体的构建与鉴定结果.结果:构建的真核表达重组体pcDNA3-可溶性血管内皮牛长因子受体1经过双酶切及聚合酶链反应鉴定,证实其中含有目的可溶性血管内皮生长因子受体1基因;测序结果经比对分析,证实与预期设计的编码区cDNA一致.结论:应用反转录-聚合酶链反应方法成功从人脐静脉内皮细胞中克隆出可溶性血管内皮生长凼子受体1基因,成功构建出了可溶性血管内皮生长因子受体1基因真核表达载体.     

髓样相关蛋白8真核表达载体的构建及其细胞内定位

目的:构建小鼠髓样相关蛋白8(MRP8)的真核表达栽体,观察其在NIH3T3细胞中的表达定位情况.方法:提取BALB/c小鼠肝脏组织的总RNA,通过逆转录-聚合酶链反应扩增得到MRP8编码序列,并将其克隆到带有血凝素(HA)标记的载体pcDNA3-HA上,随后将重组质粒瞬时转染NIH3T3细胞,利用荧光显微镜观察结果.结果:重组质粒经聚合酶链反应、酶切和测序鉴定证明构建正确,并且该质粒能够在NIH3T3细胞的胞浆、胞核中广泛表达,表达产物主要定位在细胞核中.结论:成功构建带有HA标签的MRP8真核表达载体.该载体能在哺乳动物细胞中有效表达并正确定位,为进一步研究MRP8作用细胞的信号通路提供了一个重要的工具.     

小鼠生精细胞发育特异基因spafa3的表达分析和克隆纯化冰

背景:雄性哺乳动物生精细胞自发性或诱发性凋亡现象与细胞凋亡相关基因有着密切的联系.spata3是一个新发现的小鼠生精细胞凋亡相关基因.目的:探讨小鼠生精细胞发育特异基因spata3的表达特性,制备高纯度的可溶性GST-SPATA3融合蛋白.设计、时间及地点:观察性实验,于2007-10/2008-08在山西医科大学生物化学与分子生物学实验室和组织学与胚胎学实验室完成.材料:pMD19-T Simple克隆载体及大肠杆菌菌株E.coli DH5α(TaKaRa公司),表达载体pET-41a(+)plasmid DNA(Novagen公司),大肠杆菌菌株E.coil BL21(DE3)(Solarbio公司);1,2,3,5,8周龄雄性和8周龄雌性BALB/c小鼠.方法:麻醉后颈椎脱臼处死小鼠,取出各小鼠的睾丸组织和8周龄小鼠的火脑、心脏、肝脏、肺、肾脏、脾脏、卵巢、子宫,提取各组织总RNA.通过聚合酶链反应、定量聚合酶链反应和原位杂交研究spata3 mRNA表达及定位:通过构建原核表达载体,诱导并纯化蛋白,制备抗体.主要观察指标:①反转录-聚合酶链反应分析spata3组织特异性表达.②荧光定量聚合酶链反应分析spata3的阶段特异性表达.③spata3 mRNA细胞定位的杂交信号.④SPATA3重组蛋白在原核细胞的表达及其纯化.⑤重组蛋白的Western blot 分析.结果:反转录-聚合酶链反应表明spata3具有显著的睾丸组织特异性表达特征;实时定量聚合酶链反应显示spata3在精子发生后期高表达,可能与精子细胞的变态成形过程密切相关;原位杂交证明spata3转录本主要定位在圆形和长形精子细胞内,进一步提示该基因参与了精子细胞发育后期的形态变化.DNA序列测定和SDS-PAGE分析证明spata3原核表达载体构建成功并可被商效诱导表达;Western blot印迹杂交显示纯化的SPATA3重组蛋白具有高度的特异性.结论:spata3是小鼠睾丸组织特异表达的精子发生相关基因,在圆形和长形精子细胞中处于高水平转录状态;实验获得的高纯度可溶性融合蛋白完全满足后期抗体制备的需要.     

3-hydroxy-3-methylglutaric aciduria: Deficiency of 3-hydroxy-3-methylglutaryl coenzyme a lyase

A marked deficiency of 3-hydroxy-3-methylglutaryl coenzyme A lyase activity is present in cultured skin fibroblasts from a baby with 3-hydroxy-3-methylglutaric aciduria.     

Pharmacokinetics of 3''-fluoro-3''-deoxythymidine and 3''-deoxy-2'',3''-didehydrothymidine in rats.

Concentrations of 3'-fluoro-3'-deoxythymidine (FDT) and 3'-deoxy-2',3'-didehydrothymidine (D4T) in plasma declined in a biexponential fashion. Total clearance of D4T (1.75 +/- 0.22 liters/h/kg; mean +/- standard deviation) was significantly greater than that of FDT (1.19 +/- 0.19 liters/h/kg) owing to greater renal and nonrenal clearances of the former. Steady-state volumes of distribution of FDT (1.20 +/- 0.12 liters/kg) and D4T (1.07 +/- 0.15 liters/kg) were similar.     

Pharmacokinetics of 3''-fluoro-3''-deoxythymidine and 3''-deoxy-2'',3''-didehydrothymidine in rhesus monkeys.

3'-Fluoro-3'-deoxythymidine and 3'-deoxy-2',3'-didehydrothymidine are nucleoside analogs which inhibit human and simian immunodeficiency virus in vitro. The pharmacokinetic properties of these compounds in rhesus monkeys after intravenous, oral, and subcutaneous administration of the drug were compared. Half-lives, total clearances, and steady-state volumes of distribution of the two drugs were determined. The half-lives for the drugs by the different routes were between 0.58 and 1.4 h. Oral bioavailability of 3'-deoxy-2',3'-didehydrothymidine was incomplete, with an average of 42% +/- 15% of the dose reaching the systemic circulation. Absorption of 3'-fluoro-3'-deoxythymidine after oral administration was variable, with bioavailability ranging from 21 to 95%. Bioavailability after subcutaneous administration ranged from 59 to 77% for 3'-deoxy-2',3'-didehydrothymidine and from 52 to 59% for 3'-fluoro-3'-deoxythymidine. The ratio of concentrations in cerebrospinal fluid and serum for the drugs was about 0.15 at 1 h after drug administration and was independent of the route of administration, suggesting that a nucleoside carrier-mediated process is involved in the transport of these compounds to the central nervous system. Because of the similar metabolism of nucleoside analogs in monkeys and humans, the potential glucuronide formation was assessed. Whereas the glucuronide of 3'-fluoro-3'-deoxythymidine was readily detected in urine, the amount of 3'-deoxy-2',3'-didehydrothymidine glucuronidated was small or not detectable in one-half of the urine samples. Pharmacokinetic parameters for the two drugs were similar to each other and analogous to those for 3'-azido-3'-deoxythymidine in monkeys, suggesting that the same dose and scheduling of the drug can be used for all three compounds in prophylactic and therapeutic efficacy drug studies in rhesus monkeys.     

Antiviral Activity of 3-Deazaguanine, 3-Deazaguanosine, and 3-Deazaguanylic Acid

3-Deazaguanine (ICN 4221), 3-deazaguanosine (ICN 4793), and 3-deazaguanylic acid (ICN 5412) represent a new class of synthetic guanine analogs having antiviral activity. In vitro, nine ribonucleic acid and seven deoxyribonucleic acid viruses were inhibited, including influenza, parainfluenza, rhino-, vesicular stomatitis, adeno-, herpes-, cytomegalo-, vaccinia, pseudorabies, and myxoma viruses. They were effective orally against influenza types A and B and parainfluenza type 1 (Sendai) virus infections in mice, with a therapeutic index of 16 against the latter two viruses. The course of herpes encephalitis was altered only when the drugs were applied directly into the brain. In addition, these drugs were effective inhibitors of Friend leukemia virus-induced splenomegaly in mice; treatment also produced extensions of life in these animals.     

亚急性甲状腺炎33例临床分析

目的 探讨亚急性甲状腺炎的病因、临床表现、诊断及治疗。方法 对33例患者的病史，临床表现，实验室资料及治疗进行总结分析。结果 患病的女性多见，占78．7％，病前无上怂病史记载：所有病例均有甲状腺肿大并触痛，彩超均有甲状腺肿大伴低回声，所有患者经口服泼尼松治疗效果好。结论 为减少漏诊、误诊，对咽痛伴发热病例，按上感治疗无效且持续时间较长应警惕本病。注意触诊甲状腺有无肿痛并进行必要的辅助检查。肾上腺糖皮质激素是治疗本病唯一确切有效药物。     

3-Methylcrotonylglycine excretion in 3-hydroxy-3-methylglutaric aciduria

1. 3-Methylcrotonylglycine was identified in urine from an infant with 3-hydroxy-3-methylglutaric aciduria. 2. The concentration of 3-methylcrotonylglycine in urine was approximately one sixth of that of the other metabolite of 3-methylcrotonyl-CoA, 3-hydroxyisovaleric acid. 3. The presence of both metabolites in the infant's urine indicates an inhibition of 3-methylcrotonyl-CoA carboxylase activity in tissues of the infant.     

In-plane stimulated emission of polycrystalline CH3NH3PbBr3 perovskite thin films

Hybrid organic–inorganic lead halide perovskites have been investigated extensively within the last decades, for its great potential in efficient solar cells and as an ideal light source. Among the studies on stimulated emission (SE), the emission is either out-of-plane for polycrystalline films or in-plane with randomly aligned single microcrystals and nanowires. In this work, we revealed in-plane propagation of SE from bromine-based perovskite polycrystalline thin films (CH₃NH₃PbBr₃, or MAPbBr₃). The output from in-plane SE is an order higher than the out-of-plane emission. It is proposed that large crystalline flakes in the films lead to the in-plane lasing phenomena. The output coupling can be found at grain boundaries, intergrain gaps, and artificial structures. Simulative results support the experimental phenomenon that large crystalline grains are profitable for in-plane propagation and over 90% photons can be sufficiently outcoupled when the gap is larger than a micron. Considering the fabrication and handling convenience, we propose that the MAPbBr₃ thin films can be easily integrated for in-plane applications as the light source for photonic chips etc.

MAPbBr₃ perovskite thin film contains large crystal flakes, which support the in-plane stimulated emission and its propagation within these polycrystalline films. The emission scatters at the natural or artificial edge of the film.     

3-Hydroxy-3-methylglutaric aciduria: a new assay of 3-hydroxy-3-methylglutaryl-CoA lyase using high performance liquid chromatography

A new assay has been developed for 3-hydroxy-3-methylglutaryl-CoA lyase, the final enzyme in the leucine degradative pathway. The assay was performed by incubating lysates of fibroblasts with [glutaryl-3-¹⁴C](d,l)-3-hydroxy-3-methylglutaryl coenzyme A. The products were analysed by high performance liquid chromatography with continuous liquid scintillation counting. This provided simultaneous identification and quantification of one of the enzymatic products, [3-¹⁴C] acetoacetic acid. The mean 3-hydroxy-3-methylglutaryl-CoA lyase activity in fibroblasts from five controls was 732 ± 81 (SD) pmol/min · mg protein. Using this assay, we have studied skin fibroblasts cultured from a patient with 3-hydroxy-3-methylglutaric aciduria and found 3% of normal 3-hydroxy-3-methylglutaryl-CoA lyase activity. The activities in skin fibroblasts cultured from the parents were 46 and 53% of control activity which is consistent with heterozygocity. Kinetic studies of 3-hydroxy-3-methylglutaryl-CoA lyase in skin fibroblasts cultured from two normal subjects yielded K_m values of 14.4 and 18.8 μmol/l for 3-hydroxy-3-methylglutaryl-CoA.     

Low temperature scintillation performance of a Br-doped CH3NH3PbCl3 single-crystalline perovskite

Time response and light yield are two of the most important features of a scintillation detector, and are mostly determined by the luminescence properties of the scintillator. Here we have investigated the radioluminescence (RL) characteristics of a single-crystalline hybrid lead halide perovskite at both room temperature and low temperature. A dual-channel single photon correlation (DCSPC) system with a vacuum chamber is employed for the measurement. A rise time faster than 100 ps and several times enhancement of the crystal scintillation performances at low temperature have been observed. These behaviors demonstrated that bulk solution-grown single crystals of hybrid lead halide perovskites (MAPbCl₃ and Br-doped MAPbBr_0.08Cl_2.92, where MA = CH₃NH₃) can serve as stable scintillating materials for pulsed gamma detectors. In addition, this work provides a pathway for perovskite application and also attracts attention to investigating low-temperature scintillators.

Time response and light yield are two of the most important features of a scintillation detector, and are mostly determined by the luminescence properties of the scintillator.