10月龄APP/PS1双转基因AD小鼠海马超微结构特征的观察

目的:观察APP/PS1双转基因小鼠海马内Aβ沉积的形态特征。方法:以10月龄雄性APP/PS1双转基因小鼠和C57BL/6小鼠为研究对象,采用Aβ免疫组化和透射电镜技术,观察海马部位Aβ的沉积情况及相关的病理特征。结果:在双转基因小鼠海马内存在致密性神经炎性斑块及营养障碍性突起,但脑微血管壁的Aβ沉积不甚明显;营养障碍性突起及神经细胞、微血管内皮细胞、周细胞内存在大量的自噬泡及次级溶酶体,提示该模型存在自噬溶酶体途径功能紊乱。结论:该鼠模拟了AD的老年斑及相关退行性变等病理改变,其中可能伴有细胞多种代谢的变化及血脑屏障功能的变化。从老年斑角度而言,该动物是成功的阿尔茨海默病动物模型,可用于AD的生化、病理研究及新治疗方法的探索。     

脑红蛋白在绵羊视网膜中的分布

目的:探讨脑红蛋白在绵羊视网膜的分布特征。方法:利用免疫组织化学显色SP法,观察脑红蛋白在健康成年绵羊视网膜中的分布情况。结果:脑红蛋白在绵羊视网膜的视神经纤维层、内网状层、外网状层和光感受器内节段中有强阳性表达,在视网膜的内核层和节细胞层有弱阳性表达,在视网膜外核层、光感受器外节段和色素上皮层中未见有阳性表达,内界膜、外界膜和视神经中亦有脑红蛋白阳性表达。绵羊视网膜脑红蛋白阳性表达的细胞类型主要有节细胞、双极细胞和光感受器细胞,其中节细胞的阳性表达定位于细胞质,胞核中未见表达。结论;除外核层、光感受器外节段和色素上皮层外,脑红蛋白在绵羊视网膜其他各层中均有表达,提示脑红蛋白在维持视网膜中氧平衡状态时发挥重要作用。     

家庭支持对脑卒中偏瘫患者情绪和生活质量的影响

目的:探讨家庭支持对脑卒中偏瘫患者焦虑抑郁情绪和生活质量的影响。方法:对入组90例患者采用家庭支持量表、焦虑自评量表(SAS)、抑郁自评量表(SDS)和世界卫生组织生存质量测定简表(WHOQOL-BREF)进行评定,并以家庭支持得分高低将患者分为两组,比较两组的焦虑抑郁和生活质量情况。结果:160%的脑卒中偏瘫患者家庭支持较低;高家庭支持组SAS和SDS评分均明显低于低家庭支持组,具有显著统计学差异(t=-2.69,-3.12;P0.01);2高家庭支持组WHOQOL-BREF因子评分均高于低家庭支持组,其中社会领域差异显著(t=2.23,P0.05),心理领域差异非常显著(t=2.75;P0.01),具有统计学意义。结论:家庭支持能明显改善脑卒中偏瘫患者的焦虑抑郁状况,提高其生活质量。     

Structure of Arabidopsis CESA3 catalytic domain with its substrate UDP-glucose provides insight into the mechanism of cellulose synthesis

Cellulose is synthesized by cellulose synthases (CESAs) from the glycosyltransferase GT-2 family. In plants, the CESAs form a six-lobed rosette-shaped CESA complex (CSC). Here we report crystal structures of the catalytic domain of Arabidopsis thaliana CESA3 (AtCESA3^CatD) in both apo and uridine diphosphate (UDP)-glucose (UDP-Glc)–bound forms. AtCESA3^CatD has an overall GT-A fold core domain sandwiched between a plant-conserved region (P-CR) and a class-specific region (C-SR). By superimposing the structure of AtCESA3^CatD onto the bacterial cellulose synthase BcsA, we found that the coordination of the UDP-Glc differs, indicating different substrate coordination during cellulose synthesis in plants and bacteria. Moreover, structural analyses revealed that AtCESA3^CatD can form a homodimer mainly via interactions between specific beta strands. We confirmed the importance of specific amino acids on these strands for homodimerization through yeast and in planta assays using point-mutated full-length AtCESA3. Our work provides molecular insights into how the substrate UDP-Glc is coordinated in the CESAs and how the CESAs might dimerize to eventually assemble into CSCs in plants.

Cellulose, a linear homopolymer of d-glucopyranose linked by β-1,4-glycosidic bonds, is the major structural component of the cell walls of plants, oomycetes, and algae and constitute the most abundant biopolymer on Earth (1). Cellulose is synthesized by cellulose synthases (CESAs) that belongs to the glycosyltransferase GT-2 superfamily (1, 2). In land plants, cellulose is produced at the plasma membrane by six-lobed rosette-shaped CESA complexes (CSCs) where each CESA is thought to synthesize one cellulose chain (3). The precise number of CESAs per CSC is unresolved but estimated to range between 18 and 36 (4–6).Plants contain multiple cesa genes, with 10 found in the Arabidopsis genome (7). Of these, CESA1, CESA3, CESA6, and the CESA6-like CESAs (i.e., CESA2, CESA5, and CESA9) are involved in primary cell wall formation, whereas CESA4, CESA7, and CESA8 participate in secondary cell wall formation (8–12). These two types of CSCs form heterotrimeric complexes with a ratio of 1:1:1 (13, 14). The Arabidopsis CESAs share an overall sequence identity of ∼60% and have seven transmembrane helices (15). In plants, the catalytic domain (CatD) of the CESAs is located between the second and third transmembrane helices and contains a canonical D, D, D, QxxRW motif (1). While there are similarities between the plant CatD and its counterpart in bacterial cellulose synthases, the CatD is flanked by two plant-specific domains, the so-called plant-conserved region (P-CR) and class-specific region (C-SR) (16). These domains are proposed to have important functions in cellulose synthesis and CESA oligomerization (17).The oligomerization of plant CESAs is thought to be important for the final CSC assembly, and multiple oligomeric states of CESAs, including homodimers, have been reported (18, 19). For example, immunoprecipitation assays using CESA7 fused to a dual His/STRP-tag demonstrated that CESA4, CESA7, and CESA8 could form independent homodimers, and it was hypothesized that the CESA homodimerization may contribute to early stages of CSC assembly. These homodimers might then be converted into CSC heterotrimeric configurations (19). This feature poses a marked difference from the bacterial cellulose synthase complex. However, how CESA homodimers are formed and how they function in cellulose synthesis are unknown.To comprehend the mechanisms behind plant cellulose synthesis, it is essential to acquire structural information about plant CESAs. Indeed, the BcsA–BcsB complex structure from Rhodobacter greatly aided our understanding of the cellulose synthesis in bacteria (20). Nevertheless, there are many differences between bacterial and plant CESAs and the corresponding protein complexes. Extensive efforts have been undertaken to acquire plant CESA structural information, including homology modeling and small-angle X-ray scattering analyses (5, 6, 16, 21, 22). While these efforts have been important to form new hypotheses, they did not reveal significant insights into substrate coordination, cellulose chain extrusion, and complex assembly. Recently, a homotrimeric CESA8 structure from Populus tremula × tremuloides was resolved by cryogenic electron microscopy (cryo-EM), which offered significant new molecular understanding of cellulose microfibril biosynthesis and CESA coordination within the CSC (15). Here we report the crystal structures of Arabidopsis CESA3 CatD (AtCESA3^CatD) in apo and uridine diphosphate (UDP)-glucose (UDP-Glc) bound forms and outline how the CatD might contribute to CESA homodimerization and substrate coordination.     

经十二指肠镜括约肌切开胆总管结石的处理(附168例报告)

目的：采用各种方法处理不同大小的胆总管结石。方法：于1986年3月至1996年9月经内镜括约肌切开（EST）治疗胆总管结石168例，其中单颗结石63例，2颗结石56例，3颗以上结石49例，最多一例8颗结石，结石的直径为5～25mm不等。结果：165例（98．2％）切开成功，3例失败。161例（95．8％）结石排出，其中96例（59．6％）结石自然排入肠道，57例（35．4％）采用网篮或气囊取出结石，6例（3．7％）采用碎石网篮碎石后排出，2例（1．2％）经震波碎石后排出。术后出现胃肠道出血1例（0．6％），胰腺炎1例（0．6％），胆管炎3例（1．8％）。48例术后行胃肠钡餐检查，43例胆道内无钡剂返流，2例胆道内有积气，3例有钡剂返流入胆道，但无临床症状。结论：EST是目前治疗胆管结石的重要手段之一。     

Different costimulation signals used by CD4(+) and CD8(+) cells that independently initiate rejection of allogenic hepatocytes in mice

The current study evaluated the role of CD40/CD40 ligand (CD40L) and CD28/B7 costimulation signals during alloimmune responses independently mediated by CD4(+) or CD8(+) T cells. Allogeneic hepatocytes were transplanted into CD8 or CD4 knock out (KO) mice under cover of costimulatory blockade. Rejection of FVB/N (H-2(q)) hepatocytes occurred by day 10 posttransplant in untreated CD8 or CD4 KO (H-2(b)) mice. Treatment of CD8 or CD4 KO mice with anti-CD40L monoclonal antibody (mAb; MR1) resulted in significant prolongation of hepatocyte survival indicating that CD40/CD40L interactions were critical in both CD4(+) and CD8(+) T-cell initiated hepatocyte rejection. Anti-CD40L mAb also prolonged hepatocyte survival in B-cell KO (H-2(b)) mice, indicating that the efficacy of CD40/CD40L blockade in preventing hepatocyte rejection was B-cell (and antibody) independent. In contrast, treatment with CTLA4 fusion protein (CTLA4Ig), prolonged hepatocyte survival in CD8 KO but not CD4 KO mice, showing that CD28/B7 interactions were important in CD4(+) but not CD8(+) T-cell initiated hepatocyte rejection. Under selected circumstances, such as in CD40 KO mice, both CD4(+) and CD8(+) T cells mediate hepatocyte rejection in the absence of CD40/CD40L costimulation and without a significant contribution from CD28/B7 costimulation signals. These results highlight the disparate roles of CD40/CD40L and CD28/B7 costimulation signals in CD4(+) versus CD8(+) T-cell mediated immune responses to allogeneic hepatocytes. The CD4(+) T-cell independent, CD40L-sensitive, CD28/B7-independent pathway of CD8(+) T-cell activation in response to transplantation antigens is novel.     

炎性相关细胞因子和心肌梗死微循环再灌注状态的关系

目的　观察急性心肌梗死 (AMI)患者梗死相关血管 (IRA)开通前后炎性细胞因子的动态变化及其与心肌组织水平灌注状态的关系。方法　 (1)测定 8例健康人和 2 2例AMI患者急诊冠状动脉介入治疗术 (PCI)前即刻 ,术后 12、2 4h ,血浆白细胞介素 (IL) 1β、肿瘤坏死因子 (TNF)α、IL 10的变化。 (2 )按照再灌注后 2h心电图ST段回落是否 >70 % ,将 2 2例AMI患者分为 :A组 (ST回落≥ 70 % )12例和B组 (ST回落 <70 % ) 10例 ,比较两组患者IL 1β、TNFα、IL 10的变化幅度。 结果　 (1)治疗前A、B两组AMI患者血浆TNFα、IL 10略高于健康对照组 ,但差异无统计学意义 (P >0 0 5 ) ;而IL 1β显著高于健康对照组 (P <0 0 5 ) ;再灌注后 12、2 4hA、B两组血浆IL 1β和TNFα均较术前显著增高 (P <0 0 1,P <0 0 5 ) ,B组血浆IL 10较术前显著增高 (P <0 0 5 ) ,A组则无此变化 (P >0 0 5 )。 (2 )A、B两组间比较 ,治疗前TNFα、IL 1β、IL 10差异均无显著性 (P >0 0 5 ) ;成功PCI、IRA血流达TIMI 3级者 ,B组患者血浆IL 1β、TNFα、IL 10 ,在再灌注 12h显著高于A组 (P <0 0 1,P <0 0 5 ,P <0 0 5 ) ,再灌注 2 4h ,IL 1β、IL 10仍然高于A组 (P <0 0 5 )。 (3)A、B两组患者抗炎因子IL 10的升高幅度均显著低于致炎     

顽固性室性早搏的导管标测与射频消融治疗

采用射频导管消融术对症状明显、药物无效的１０例顽固性室性早搏（简称室早）进行治疗。将消融电极送至右室流出道区域，以Ｓ１Ｓ１或ＲＳ２早搏刺激标测到与体表１２导联心电图记录的自发室早ＱＲＳ波群图形完全相同，并且激动标测时自发室早的局部电图较体表心电图ＱＲＳ波群提前３０ｍｓ以上的部位为消融靶点。以室早在放电后１０ｓ内消失，维持稳定窦性心律３０～６０ｍｉｎ为即刻成功标准。９例患者经１０～２０Ｗ、消融６０～１８０ｓ，早搏和短阵室速完全消失；１例失败。平均随访１１个月，未服任何抗心律失常药物症状消失，复查心电图和动态心电图，９例中８例无早搏、１例为偶发室早，均无并发症。提示射频导管消融术是治疗某些右室流出道早搏的可行方法。