CELLULAR DIFFERENTIATION OF HEART AND VESSEL

1.心前中胚层与生长因子检测在生长因子存在下，具有向心脏搏动心肌分化潜能的心前中胚层是否发育为搏动组织。胰岛素样生长因子、激活素A和碱性成纤维细胞生长因子对心肌分化有促进作用。2.心脏发育和含钙线粒体A细胞化学和X射线微核分析。3.肌浆网与心脏发育观察早期鸡胚胎心脏肌浆网的发育及其钙释放功能。管状性和连接性SR分别出现在第11期和第12期。Fura-2检测细胞内钙离子浓度提示SR可能在10.4期诱导其功能。大动脉移位(TGA)是先天性心脏畸形之一。用扫描电子显微镜观察不同发育阶段的心腔内铸型模型。TGA的主要形态异常是圆锥体垫脊发育不全。5.用原位杂交技术检测转化生长因子β3和鸡胚胎发生中TGFBETA3的RNA转录本。TGFBETA3mRNA主要分布于发育中的动脉、心脏及体腔上皮细胞。提示TGFBETA3可能在包括心血管系统在内的中胚层发育中起重要作用。

1.Precardiac mesoderm and growth factorsPrecardiac mesoderm, which has potential ability of differentiation to beating myocardium in the adult heart, was examined whether it developed to beating tissue in the presence of growth factors. Insulin-like growth factor, activin A,and basic fibroblast growth factor showed a stimulating effect on myocardial differentiation.2.Heart development and calcium-containing mitochondriaA calcium-containing vacuolated mitochondria in chick developing heart was examined by cytochemistry and X-ray microanarysis. Results suggested that vacuolated mitochondria regulated intracellular calcium concentration.3.Sarcoplasmic reticulum and heart developmentDevelopment of sarcoplasmic reticulum (SR) and its calcium releasing function were examined in early chick embryonic heart. Tubular SR and junctional SR appeared at stage 11 and 12, respectively. Intracellular calcium concentration by fura-2 suggested that SR might elicit its function at stage 10.4.Transposition of the great arteries (TGA)Developmental mechanism of TGA,one of the congenital heart malformations, was examined in retinoic-acid induced mouse model. Intraracardiac cast models at various developmental stages were examined by scanning electron microscopy. Primary morphological abnormality of TGA was hypoplasia of cushion ridges in conus cordis.5.Transforming growth factor (TGF) BETA3 and chick embryogenesismRNA transcripts of TGFBETA3 was examined in developing chick embryos by in situ hybridization. TGFBETA3 mRNA was distributed mainly at developing artery and heart as well as epithelium of body cavity. This suggested that TGFBETA3 may play important roles in mesodermal development including cardiovascular system.