黄芪抗新生大鼠大脑皮层神经细胞缺氧性凋亡研究

目的:研究黄芪对体外培养的新生大鼠大脑皮层神经细胞缺氧性凋亡的保护机理.方法:应用"Neurobasal加B27 Supplement"体外培养大鼠脑皮层神经细胞并在缺氧条件下使用Trypanblue拒染法、Hoechst 33342荧光染色法、免疫细胞化学染色法,观察黄芪对原代神经细胞的抗凋亡保护作用.结果:在10mg/ml～100mg/ml的浓度范围内,黄芪注射液能显著降低缺氧诱导的神经细胞凋亡率,增加了缺氧的神经细胞Bcl-2蛋白的表达,同时也减少了Bax蛋白的表达,提高Bcl-2/Bax比值.结论:黄芪对缺氧条件下的神经细胞有直接的抗凋亡作用,其作用机理是通过上调Bcl-2蛋白和下调Bax蛋白的表达,达到调节缺氧的神经细胞避免凋亡.     

Epiphyseal ossification centers in the assessment of fetal maturity: sonographic correlation with the amniocentesis lung profile

The epiphyseal ossification centers of the distal femur (DFE) and proximal tibia (PTE) appear and enlarge during the third trimester of pregnancy. Late in the third trimester, the epiphysis of the proximal humerus (PHE) begins to ossify in some fetuses. Using the amniocentesis lung profile to determine the value of sonographic epiphyseal visualization as a predictor of pulmonary maturity, we studied 50 fetuses prospectively and compared the sonographic epiphyseal findings with results from the amniocentesis lung profiles. Nine fetuses with a visible PHE had a mature amniocentesis lung profile (accuracy of positive prediction = 100%), and then fetuses with an immature amniocentesis lung profile had no visible PHE (conegativity = 100%). Fetuses in which the combined DFE and PTE diameters were greater than 11 mm or in which the DFE and the PTE diameters were similar in size (DFE less than or equal to 1 mm larger than PTE) also yielded positive results. Copositivity and accuracy of prediction of an immature amniocentesis lung profile, on the other hand, were low (22%-25%) for the same epiphyseal parameters. These data suggest that antenatal visualization and measurement of the epiphyseal ossification centers of the fetal knee and shoulder may help to identify fetuses that would have a mature amniocentesis lung profile.     

Mouse choroideremia gene mutation causes photoreceptor cell degeneration and is not transmitted through the female germline

Choroideremia (CHM) is an X-linked progressive eye disorder which results from defects in the human Rab escort protein-1 (REP-1) gene. A gene targeting approach was used to disrupt the mouse chm/rep-1 gene. Chimeric males transmitted the mutated gene to their carrier daughters but, surprisingly, these heterozygous females had neither affected male nor carrier female offspring. The targeted rep-1 allele was detectable, however, in male as well as female blastocyst stage embryos isolated from a heterozygous mother. Thus, disruption of the rep-1 gene gives rise to lethality in male embryos; in female embryos it is only lethal if the mutation is of maternal origin. This observation can be explained by preferential inactivation of the paternal X chromosome in murine extraembryonic membranes suggesting that expression of the rep-1 gene is essential in these tissues. In both heterozygous females and chimeras the rep-1 mutation causes photoreceptor cell degeneration. Consequently, conditional rescue of the embryonic lethal phenotype of the rep-1 mutation may provide a faithful mouse model for choroideremia.      

Mutations in the Chediak-Higashi syndrome gene (CHS1) indicate requirement for the complete 3801 amino acid CHS protein

Chediak-Higashi syndrome (CHS) is a rare, usually fatal, autosomal recessive disorder characterized by severe immunologic defects, reduced pigmentation, progressive neurologic dysfunction and a bleeding diathesis. The hallmark of CHS is giant organelles and giant granules in many different cell types, most likely the result of defective trafficking of specific organellar and granular proteins necessary for the normal genesis, structure or function of these cytoplasmic components. The CHS1 gene has recently been identified and shown to be homologous to the beige locus of the mouse; however, there has been disagreement as to the length of the functional CHS1 mRNA and protein. Here we report homozygous CHS1 gene mutations in two of the original probands we used to map the gene to 1q42-q44. One of these, a frameshift at codon 3197, supports our assertion that the functional CHS protein is a predicted 3801 amino acid polypeptide encoded by a 13.5 kb mRNA.      

Identification and characterization of human genes encoding Hprp3p and Hprp4p, interacting components of the spliceosome

Nuclear RNA splicing occurs in an RNA-protein complex, termed the spliceosome. U4/U6 snRNP is one of four essential small nuclear ribonucleoprotein (snRNP) particles (U1, U2, U5 and U4/U6) present in the spliceosome. U4/U6 snRNP contains two snRNAs (U4 and U6) and a number of proteins. We report here the identification and characterization of two human genes encoding U4/U6-associated splicing factors, Hprp3p and Hprp4p, respectively. Hprp3p is a 77 kDa protein, which is homologous to the Saccharomyces cerevisiae splicing factor Prp3p. Amino acid sequence analysis revealed two putative homologues in Caenorhabditis elegans and Schizosaccharomyces pombe. Polyclonal antibodies against Hprp3p were generated with His-tagged Hprp3p over- produced in Escherichia coli . This splicing factor can co- immunoprecipitate with U4, U6 and U5 snRNAs, suggesting that it is present in the U4/U6.U5 tri-snRNP. Hprp4p is a 58 kDa protein homologous to yeast splicing factor Prp4p. Like yeast Prp4p, the human homologue contains repeats homologous to the beta-subunit of G- proteins. These repeats are called WD repeats because there is a highly conserved dipeptide of tryptophan and aspartic acid present at the end of each repeat. The primary amino acid sequence homology between human Hprp4p and yeast Prp4p led to the discovery of two additional WD repeats in yeast Prp4p. Structural homology between these human and yeast splicing factors and the beta-subunit of G-proteins has been identified by sequence-similarity comparison and analysis of the protein folding by threading. Structural models of Hprp4p and Prp4p with a seven-blade beta-propeller topology have been generated based on the structure of beta-transducin. Hprp3p and Hprp4p have been shown to interact with each other and the first 100 amino acids of Hprp3p are not essential for this interaction. These experiments suggest that both Hprp3p and Hprp4p are components of human spliceosomes.      

Arteria thyroidea ima arising from the brachiocephalic trunk with bilateral absence of inferior thyroid arteries: a case report

Summary The anomalous first parts of the left and right subclavian aa. had no inferior thyroid aa. in the neck region. The thyroidea ima a. was found to arise from the brachiocephalic trunk, and bifurcated into two branches almost immediately after its origin. These branches ascended in front of the trachea and entered the bases of the right and left lobes of the thyroid gland. The left vertebral a. arose from the aortic arch in the superior mediastinum. The possible existence of this anomaly is important for parathyroid localization studies, in neck surgery and especially in tracheostomy.

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Arteria thyroidea ima (anciennement artère thyroïdienne moyenne de Neubauer) naissant du tronc brachio-céphalique avec absence des artères thyroïdiennes inférieures

Résumé Les parties intiales des artères subclavières gauche et droite étaient anormales. Elles ne donnaient pas, dans la région cervicale, d'artère thyroïdienne inférieure. L'artère thyroidea ima naissait du tronc brachio-céphalique et se bifurquait, peu après son origine, en deux branches. Ces branches avaient un trajet ascendant ventralement à la trachée et pénétraient le pôle inférieur des lobes droit et gauche de la glande thyroïde. L'artère vertébrale gauche provenait de l'arc aortique et se situait dans le médiastin supérieur. La possibilité d'une telle anomalie est importante à connaître dans la recherche du site des glandes parathyroïdes et dans la chirurgie du cou, spécialement au cours des trachéotomies.