Gumpel-Pinot M
Arch Anat Microsc Morphol Exp. 1981;70(1):1-14.
Stage 17 (Hamburger and Hamilton) limb mesoderm, isolated and cultured in vitro differentiates into cartilage (11.5% of the explants). However, chondrogenesis is considerably improved in the presence of ectoderm, whether the interacting tissues are in close contact or separated by the vitelline membrane. Stage 15-16 limb mesoderm cultured in vitro is unable to differentiate into cartilage. Previous experiments have shown that a contact between ectoderm and mesoderm is necessary for the induction of cartilage to take place. However, when the vitelline membrane separates the two tissues, cartilage differentiation occurs in 16.3% of the explants. Can a contact between the two interacting tissues be established through the vitelline membrane? Ultrastructural studies of the relationships between ectodermal and mesodermal cells and the vitelline membrane have shown that such a contact can be achieved by means of long mesodermal cell processes penetrating deeply into the vitelline membrane.
第17阶段（汉堡和汉密尔顿）的肢体中胚层，在体外分离培养后可分化为软骨（占外植体的11.5%）。然而，无论相互作用的组织是紧密接触还是被卵黄膜隔开，在外胚层存在的情况下软骨形成都有显著改善。体外培养的第15 - 16阶段肢体中胚层无法分化为软骨。先前的实验表明，外胚层和中胚层之间的接触是软骨诱导发生所必需的。然而，当卵黄膜分隔这两种组织时，16.3%的外植体发生了软骨分化。两个相互作用的组织之间能否通过卵黄膜建立接触？对外胚层和中胚层细胞与卵黄膜之间关系的超微结构研究表明，这种接触可以通过中胚层细胞的长突起深入穿透卵黄膜来实现。
