Hematopoiesis in young human embryos
Hematopoiesis in young human embryos
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DOI：
10.1002/aja.1000670103
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发表时间：
1940-07-01
影响因子：
--
通讯作者：
Bartelmez, GW
中科院分区：
文献类型：
--
作者：
Bloom, W;Bartelmez, GW
造血是在一系列固定良好的年轻人类卵子中描述的，从13天的阶段(类似于彼得斯卵子)开始，专门为造血而染色。除原始条纹阶段的腹柄和18体节胚胎的2个病灶外，早期造血仅局限于卵黄囊。造血细胞以大淋巴细胞型为主，但早在头部突起阶段，卵黄囊血管中就出现了与中、小淋巴细胞相对应的较小的例子。在卵黄囊中，造血细胞产生一代原始红血球和随后独立的最终红血球谱系。造血细胞还可产生巨噬细胞、巨细胞、非典型巨核细胞和髓细胞。原始的红细胞出现了。主要见于血管内，但也有少数见于腔外。最后的红细胞在血管内、间充质内和内胚层内发育。绒毛膜板、绒毛、卵黄囊和腹柄的血管原基是间充质细胞直接转化形成的。没有令人信服的证据表明它们直接从细胞滋养层发育而来。除了腹柄有3个孤立的败育灶外，至少在体节中期之前，血细胞只在卵黄囊的血管中发育。
Hematopoiesis is described in a series of well fixed young human ova, specifically stained for hematopoiesis, starting with the 13-day stage (similar to the Peters ovum). Except for a small focus in the belly stalk of the primitive streak stage and 2 foci in that of the 18-somite embryo, early hematopoiesis is confined to the yolk sac. The hemocytoblasts are predominantly of large lymphocyte type, but smaller examples corresponding to medium sized and small lymphocytes are found in the yolk sac vessels as early as the head process stage. In the yolk sac, hemocytoblasts give rise to a generation of primitive erythrocytes and to a subsequent, independent lineage of definitive erythrocytes. The hemocytoblasts also give rise to macrophages, giant cells, atypical megakaryocytes, and myelocytes. The primitive erythrocytes arise . primarily intravascularly although a few are also found extravascu-larly. The definitive erythrocytes develop within vessels, in the mesenchyme, and within the entoderm. Blood vessel primordia in the chorion plate, villi, yolk sac and belly stalk arise by direct transformation of mesenchymal cells. There is no convincing evidence of their direct development from cytotrophoblast. Except for 3 isolated abortive foci in the belly stalk, blood cells develop only in the yolk sac vessels until at least mid-somite stages.