力竭运动大鼠心室肌蛋白质组表达特征

目的:采用蛋白质组学技术,建立安静和递增运动负荷训练后力竭大鼠心室肌蛋白质组的差异性表达谱,初步筛选出心室肌对力竭运动产生反应的目标蛋白质。方法:实验于2007-03在湖南师范大学生命科学学院蛋白质化学与蛋白质组学国家教育部重点实验室和省级运动人体科学实验室完成。①实验分组:10只SD雄性大鼠随机分为对照组和运动组,每组5只。②实验方法:运动组经过7周的大强度递增运动负荷训练后(最后一次力竭),对两组心室肌组织的全蛋白进行双向凝胶电泳分离。结果:经图像分析,在运动组的电泳图谱上共展现蛋白质点(338±17)个,对照组展现蛋白质点(352±17)个。运动后差异表达的蛋白质点共有99个。对其中差异表达的9个蛋白质点进行质谱鉴定,共鉴定出7个蛋白质,Stress-70protein,NADH-ubiquinone oxidoreductase Mr75000subnunit,Long-chain specific acyl-CoA dehydrogenase,Tropomyosin-1alphachain在运动后"缺失",Nitrilase family,member2在运动后表达上调在5倍以上,一个相对分子质量为21000的未知蛋白在运动后表达下调在5倍以上,另外有两个点经鉴定均为Myosin-6,在运动后表达量相反。这些蛋白质属于收缩蛋白、能量代谢酶、分子伴侣等。结论:递增运动负荷训练后力竭时,大鼠心室肌蛋白质组明显地发生了反应。运动后"缺失"和下调的蛋白质点与心肌收缩的调控和能量代谢的方式转变以及细胞的应激反应有关,其中,成功筛选出6种在运动医学领域尚未涉足的、具有运动应激特点的目标蛋白质。     

Bradycardia and Syncope in Children Not Controlled by Pacing: Beta-Adrenergic Hypersensitivity

Cardiac pacing is frequently employed in the therapy of children with syncope and documented bradycardia. This report describes two children, ages 7 and 9 years, who underwent placement of demand ventricular pacing systems for documented bradycardia and syncope. Cardiac catheterization and intracardiac electrophysiological studies failed to show evidence of structural abnormalities, sinus node or conduction system disease, inducible arrhythmias, or VA conduction in each patient. Both patients had persistent symptoms after pacemaker implantation. Autonomic function testing with continuous heart rate and blood pressure monitoring revealed exaggerated beta-adrenergic responses to simple standing and small doses of isoproterenol. Symptoms were completely eliminated with atenolol. In these two children, cardiac pacing alone was not adequate for relief of symptoms. Autonomic mechanisms of bradycardia and hypotension should be considered prior to implantation of permanent pacing systems in children.     

Characteristics of human large granular lymphocytes and relationship to natural killer and K cells

Recent evidence, has demonstrated an association between a subpopulation of peripheral blood mononuclear cells, morphologically identified as large granular lymphocytes (LGL), and natural killer (NK) activity. We have now evaluated more directly the role of LGL in both NK activity and antibody- dependent cellular cytotoxicity (ADCC), by using highly enriched populations of LGL, obtained by centrifugation of peripheral blood mononuclear cells on Percoll discontinuous density gradients. Both spontaneous and interferon- augmented NK and ADCC activities were exclusively associated with the LGL- enriched, low density fractions. The majority of LGL formed conjugates with NK-susceptible and antibody-coated target cells. Approximately 20 percent of small conventional lymphocytes also formed conjugates with the target cells for NK, but this was not associated with cytotoxic activity. Virtually all LGL were found to have receptors for the Fc portion of IgG (FcγR). The frequency of LGL among blood leukocytes was 2-6 percent. LGL could be enriched to an average purity of 95 percent by combining discontinuous density gradient centrifugation with subsequent adsorptions of the low density fractions on monolayers of immobilized immune complexes. About 50 percent of LGL were found to be FcγR-bearing T cells (T(G)), forming low affinity rosettes with sheep erythrocytes at 4 degrees C. Only 10-20 percent of LGL formed high affinity rosettes with sheep erythrocytes at 29 degrees C. LGL could be enriched to a purity of more than 90 percent by depleting high affinity rosette-forming cells from low density Percoll fractions. LGL were only a subpopulation of T(G) cells, because some lymphocytes with conventional morphology also adhered to the immobilized immune complex monolayers and formed high affinity rosettes with sheep erythrocytes. Separation of these cells from LGL by discontinuous density gradient centrifugation indicated that they are not cytotoxic, suggesting a morphological and functional subdivision of T(G) cells. The verification in this study that virtually all human NK and K cells have a characteristic morphology adds a useful parameter to the monitoring of human lymphocytes, and the ability to purify these cells by simple physical procedures should be invaluable in their further characterization.     

Clinical and genetic analysis of Korean patients with Marfan syndrome: possible ethnic differences in clinical manifestation

Yoo E‐H, Woo H, Ki C‐S, Lee HJ, Kim D‐K, Kang I‐S, Park P, Sung K, Lee CS, Chung T‐Y, Moon JR, Han H, Lee S‐T, Kim J‐W. Clinical and genetic analysis of Korean patients with Marfan syndrome: possible ethnic differences in clinical manifestation. Marfan syndrome (MFS) is an autosomal dominant disorder of the fibrous connective tissue caused by mutations in the fibrillin‐1 (FBN1) gene. Although clinical and genetic analyses have been performed in various populations, there have been few studies in Korea. The aim of this study was to investigate the clinical characteristics and genetic background of Korean patients with MFS. In 39 Korean patients with MFS who met the Ghent criteria, the most common clinical finding was aortic dilatation and/or dissection (94.9%), whereas only 35.9% of patients had ectopia lentis. The majority of MFS patients had fewer than four of the skeletal findings required to fulfill the major skeletal Ghent criterion for MFS. Only 21% of Korean patients had major skeletal abnormalities and most cases showed only minor skeletal involvement. FBN1 gene mutations were detected in 35 out of 39 patients (89.7%), which is similar to rates presented in the previous reports. These results suggest that some clinical features in Korean patients with MFS differed from those reported in Western MFS patients.     

Upregulation of HTLV-1 and HTLV-2 expression by HIV-1 in vitro

Co-infections with HIV-1 and the human T leukemia virus types 1 and 2 (HTLV-1, HTLV-2) occur frequently, particularly in large metropolitan areas where injection drug use is a shared mode of transmission. Recent evidence suggests that HIV-HTLV co-infections are associated with upregulated HTLV-1/2 virus expression and disease. An in vitro model of HIV-1 and HTLV-1/2 co-infection was utilized to determine if cell free HIV-1 virions or recombinant HIV-1 Tat protein (200-1,000 ng/ml) upregulated HTLV-1/2 expression and infectivity. Exposure to HIV-1 increased the number of HTLV-1 antigen expressing cells, from 6% at baseline to 12% at 24 hr, and 20% at 120 hr (P < 0.05) post-exposure. A similar, although less robust response was observed in HTLV-2 infected cells. HIV-1 co-localized almost exclusively with HTLV-1/2 positive cells. Exposure to HIV-1 Tat protein (1,000 ng/ml) increased HTLV-1 p19 expression almost twofold by 48 hr, and cells co-stimulated with 10 nM phorbol myristate acetate (PMA) showed almost a fourfold increase over baseline. It is concluded that HIV-1 augments HTLV-1/2 infectivity in vitro. The findings also suggest a role for the HIV-1 Tat protein and PMA-inducible cellular factors, in HIV-1 induced HTLV-1/2 antigen expression.     

Characterization of melanocyte stimulating hormone receptor variant alleles in twins with red hair

The association between MSHR coding region variation and hair colour in humans has been examined by genotyping 25 red haired and 62 non-red Caucasians, all of whom were 12 years of age and members of a twin pair study. Twelve amino acid substitutions were seen at 11 different sites, nine of these being newly described MSHR variants. The previously reported Val92Met allele shows no association with hair colour, but the three alleles Arg151Cys, Arg160Trp and Asp294His were associated with red hair and one Val60Leu variant was most frequent in fair/blonde and light brown hair colours. Variant MSHR genotypes are associated with lighter skin types and red hair (P < 0.001). However, comparison of the MSHR genotypes in dizygotic twin pairs discordant for red hair colour indicates that the MSHR gene cannot be solely responsible for the red hair phenotype, since five of 13 pairs tested had both haplotypes identical by state (with three of the five having both identical by descent). Rather, it is likely that additional modifier genes exist, making variance in the MSHR gene necessary but not always sufficient, for red hair production.