Expression and characterization of the human YWK-II gene, encoding a sperm membrane protein related to the alzheimer betaA4-amyloid precursorprotein

The YWK-II cDNA, RSD-2, encoding a sperm membrane protein was isolated from a rat testis cDNA expression library. Using the RSD-2 insert in combination with rapid amplification of cDNA ends (RACE), the corresponding human gene was isolated from a human testis cDNA expression library. The human testis cDNA, HSD-2, is 3654 bp in length and contains an open reading frame of 763 codons. Hydropathicity analysis showed that the deduced polypeptide is a single strand transmembrane protein. The deduced polypeptide has partial homology with the amyloid precursor protein (APP) and high homology with the amyloid precursor homologue, APLP2/APPH. The YWK-II gene was mapped and assigned to human chromosome locus: 11q24-25. Northern blotting of various human tissue RNAs using the HSD-2 cDNA as a probe showed that the gene is transcribed ubiquitously. The cytoplasmic domain of HSD-2 was expressed in Escherichia coli. In-vitro studies showed that the recombinant polypeptide bound to a GTP-binding protein (G(o)) and was phosphorylated by protein kinase C and cdc2 kinase. In mammalian F11 cells, the recombinant polypeptide was found to be coupled to G(o). Thus, the YWK-II component has the characteristics of a G(o)-coupled receptor and may be involved in G(o)-mediated signal transduction pathway. Protein kinase C and cdc2 kinase may regulate this pathway in spermatozoa by phosphorylating the cytoplasmic domain of the YWK-II component.     

Persistent tubular conduction in vacuolated amphibian skeletal muscle following osmotic shock

The transverse (T-)tubules primarily function in conducting the action potentials that initiate excitation– contraction coupling in skeletal muscle but may additionally subserve longer-term roles in volume regulation, membrane fusion and other trafficking processes. Osmotic shock thus both electrically detaches the T-tubules from surface membrane (‘detubulation’) and produces tubular vacuolation. The present experiments separated these effects. An established, reference osmotic shock protocol that exposed muscles to Ca²⁺/Mg²⁺-Ringer and gradual cooling to 10°C after 18 min in glycerol–Ringer accomplished significant detubulation (77.5 ± 13.15%, mean ± SEM; n = 4). In contrast, a test protocol conducted entirely at room temperature using Mg²⁺-rather than Ca²⁺/Mg²⁺-Ringer yielded reduced (P < 0.05, post hoc Duncan's multiple range test) detubulation indices (1.67 ± 1.67%, n = 6) statistically indistinguishable from findings in fibres spared osmotic shock. Yet both osmotic shocks caused a formation of closed vacuoles, demonstrated by Sulphorhodamine B trapping, that occupied statistically similar fractions of total fibre volume (reference procedure: 14.38 ± 2.7%, n = 6; test procedure: 13.36 ± 2.00%, n = 22) in turn higher than determinations in control fibres (P < 0.05). The findings reconcile reports associating detubulation with vacuolation in osmotically shocked muscle [S. Nik-Zainal et al. (1999) J Muscle Res Cell Motil 20: 45–53; K.N. Khan et al. (2000) J Muscle Res Cell Motil 21: 79–90] with the persistence of tubular electrical activity in extensively vacuolated amphibian fibres following fatigue [J. Lannergren and H. Westerblad (1987) Acta Physiol Scand 129: 311–318; J. Lannergren et al. (1999) J Muscle Res Cell Motil 20: 19–32]. Furthermore test protocols produced higher densities of open vacuoles (13.38 ± 2.33%, n = 9) than did reference protocols (6.66 ± 1.63%, n = 20) contrary to their possible involvement in the electrophysiological changes. Abolition of tubular electrophysiological activity thus either follows or is independent of tubular vacuolation whilst sharing some of its underlying osmotic mechanisms. This revised version was published online in July 2006 with corrections to the Cover Date.     

阿尔茨海默病与雌激素受体α基因多态性的相关性探讨

目的 探讨雌激素受体α基因突变在阿尔茨海默病(AD)发病中的意义。方法 用PCR扩增66例AD患者及143例对照者的激素受体α基因突变点,经限制性内切酶消化后行凝胶电泳确定其基因型。结果 雌激素受体α基因各种基因型频率在患者组与正常对照组之间的差异无显著性。结论 就目前的调查的例数来看,激素受体α基因突变可能不足以构成阿尔茨海默病的独立遗传性危险因子。     

结直肠癌中TGF-β1表达与肿瘤浸润转移和血管形成的关系

目的　探讨结直肠癌中转化生长因子 β1(TGF β1)的表达与肿瘤浸润转移和血管形成的关系。 方法　免疫组化S P法检测 12 6例结直肠癌中TGF β1和血管内皮生长因子 (VEGF)的表达 ,同时应用CD34标记肿瘤间质中微血管密度 (MVD)。结果　 12 6例结直肠癌中TGF β1和VEGF的阳性表达率分别为 4 2 1%和 6 3 5 %。结直肠癌中TGF β1、VEGF蛋白的表达和MVD与肿瘤的浸润深度、淋巴结转移和Dukes分期呈正相关 (P <0 0 5 ) ;VEGF在TGF β1表达阳性的结直肠癌中的阳性表达率高于TGF β1表达阴性的结直肠癌 (P <0 0 5 ) ,TGF β1表达阳性的结直肠癌MVD高于TGF β1表达阴性的结直肠癌(P <0 0 5 )。结论　TGF β1可能通过间接或直接刺激肿瘤血管形成而促进结直肠癌的浸润转移     

Clinical experiences of bacteremia caused by metallo-beta-lactamase-producing gram-negative organisms.

The emergence of acquired metallo-beta-lactamase (MBL) in gram-negative bacilli is regarded as a therapeutic challenge since such enzymes are capable of hydrolyzing all beta-lactams in vitro except the monobactams. The clinical characteristics and outcome of 8 episodes of gram-negative bacteremia caused by MBL-producing isolates from January 1997 through December 2000 (Klebsiella pneumoniae, 6 isolates; Pseudomonas stutzeri, 4; Pseudomonas aeruginosa, 1; and Pseudomonas putida, 1) were analyzed. The median age of the patients was 61 years (range, 2-95 years). Most patients (n = 6, 75%) had more than 1 comorbid illness or condition and 6 patients acquired bacteremia in the intensive care unit. The median time from admission to the first positive culture was 34.5 days (range, 1-99 days). Pneumonia was the most common site of infection. Five patients (62.5%) received a carbapenem to treat bacteremia. The median time to defervescence was 6 days (range, 2-12 days). No bacteriologic failure was noted during or after antimicrobial therapy. The overall mortality rate from bacteremia caused by gram-negative, MBL-producing organisms was nil at 14 or 28 days.     

组织蛋白酶L及其抑制剂Cystatin C在曲张大隐静脉平滑肌细胞中的表达

目的:组织蛋白酶L(Cat L)及其抑制剂Cystatin C在曲张大隐静脉平滑肌细胞(SMC)中的表达。方法:术中收集曲张及正常大隐静脉标本,采用免疫组织化学、荧光免疫组织化学染色方法及计算机图像分析技术观察检测。结果:免疫组化染色可见Cat L、Cystatin C分别在曲张、正常大隐静脉中免疫反应阳性,阳性细胞主要位于SMC胞质;曲张组SMC中Cat L阳性细胞平均光密度值明显增高,Cystatin C明显降低,与正常组间差异显著;荧光免疫组织化学染色可见Cat L与曲张大隐静脉SMC共定位,Cystatin C与正常大隐静脉SMC共定位。结论:在曲张大隐静脉的SMC中Cat L表达增强,Cystatin C表达下降。这一改变可能作为大隐静脉曲张的生物学标志。     

创新思维对肾移植模型制作教学的促进作用

大鼠肾移植模型是研究肾移植排斥反应发生机制、治疗措施以及诱导免疫耐受的重要平台,但其制作复杂,在传统教学中存在诸多问题。对此,我们在教学中充分发挥创新思维,改进了教学方式,建立了多项新技术,显著提高了以显微外科技术为基础的大鼠肾移植模型制作的教学效率与质量,现将体会报告如下。1应用现代教学手段解决传统教学中的难题1.1大鼠肾移植模型的制作特点以及传统教学存在的问题该模型制作主要依赖显微外科技术,教学中,从解剖结构、手术器械到手术操作的突出特点是“精细、微小”,也是教学的难点。传统教学主要依靠文字教材以及部分挂…     

冠心康对实验性家兔动脉粥样硬化血清NO及血浆ET-1的影响

目的 :观察中药冠心康预防用药对食饵性动脉粥样硬化 (AS)家兔血清一氧化氮 (NO)及血浆内皮素 1(ET 1)的影响。方法 :采用猪油加胆固醇饲料造模法 ,建立家兔动脉粥样硬化模型。随机分为正常对照组 (N组 ) ,模型组 (M组 ) ,冠心康治疗组 (T组 ) ,复方丹参片治疗对照组 (C组 ) ,各组在实验开始 ,第 6周末 ,第 12周末取血标本测定上述参数。结果 :与M组比较 ,T组、C组均可显著提高血清NO含量 ,降低血浆ET 1含量 (P <0 .0 5 ) ,且T组与C组比较有显著差异(P <0 .0 5 )。结论 :冠心康有维持内源性ET 1和NO的平衡而保护正常内皮功能的作用 ,这可能是其防治冠状动脉粥样硬化和抗心肌缺血作用的机制之一     

CYP1A1基因多态性与急性淋巴细胞白血病的关系

目的　探讨CYP1A1基因多态性与急性淋巴细胞白血病 (ALL)遗传易感性的关系。方法　应用PCR -RFLP、ASA技术 ,分析 78例ALL患者和 112例健康人CYP1A1基因多态性 ,比较ALL患者与对照组间频率差异。结果　ALL组CYP1A1MspI基因多态位点 ,各等位基因和基因型频率与对照组比较有显著性差异 (P <0 .0 5 ) ,其中等位基因m2使患ALL的危险度提高了 1.5 4倍 ,m1m2、m2m2基因型使患ALL的危险度分别提高了 2 .2 7倍和 2 .77倍 ;ALL组CYP1A1Ile-Val各等位基因和基因型频率与对照组比较无显著性差异 (P >0 .0 5 )。结论　CYP1A1MspI基因多态可能与ALL的发生有关。