Transplantation of facial processes for repair of induced branchial arch syndromes.

A technique has been developed by which facial processes with adequately migrated neural crest tissue can be cultured and transplanted to embryos with induced craniofacial malformations. Culturing was carried out in the anterior eye chambers of adult rats or as whole embryo cultures in glass vials (n = 71). Facial processes transplanted to the anterior eye chamber differentiated to cartilage, bone, and mesenchymal tissues. It was possible to keep the embryos alive in whole tissue culture for up to 24 hours. The addition of epidermal growth factor to the culture medium resulted in accelerated growth of epithelium on the surface of the facial processes. Facial processes were accepted when transplanted to either normal or etretinate treated embryos. Epithelium covered the transplanted facial processes, neural crest tissue was seen in the centre, and capillaries were in close contact to the base of each one.

Histochemical investigations on the symphysis menti in the human fetus related to fetal skeletal maturation in the hand and foot.

Histochemical investigations on the symphysis menti region were performed on 72 human embryos and fetuses of crown-rump lengths (CRL) ranging from 16 to 162 mm, presenting skeletal maturity indices (CNO = composite number of ossified bones in the hand and foot) ranging from 0-0 to 19-11. The symphysis menti region is described in five developmental stages according to morphology and histochemical reactions at the interzone, enchondral bone formation, and Meckel's cartilage. The stages are described according to histochemical reactions for glycosaminoglucuronoglycans, collagen, glycogen, alkaline and acid phosphatase, and non-specific AS esterase. Silver impregnation followed by X-ray and histochemical control for Ca++ deposits supplemented the study. Special attention was paid to a fusion of the bilateral Meckel's cartilages in the midline characteristic of stage II. This is a finding not previously recorded in human fetuses. It is suggested to designate this fusion 'the rostral connection'. Histochemically, the fusion appeared as ordinary cartilage matrix (chondroitin-4- and/or-6-sulphate). The absence of a rostral connection characteristic of stage III is discussed. On the basis of reactions for glycosaminoglycans and activity of hydrolytic enzymes, the symphysis is characterized as a growth zone, active in mandibular growth in width as well as in length, during the first half of the prenatal period. The material available did not justify a description of skeletal development in the symphysis menti as a function of CRL, of skeletal maturation in the hand and foot, or as a function of a combination of these parameters.