Spontaneous complete clefting of the palates in a mouse fetus: a study by scanning electron microscopy and serial section reconstruction.

A 15 day mouse fetus having spontaneous complete clefting of the primary and secondary palates was studied in comparison with its normal litter mates and with normal 14 day fetuses. Specimens were studied by scanning electron microscopy at various stages of microdissection, by light microscopy of thin serial sections and by serial section reconstruction of the anterior chondrocranium of the clefted specimen and one of its normal litter mates. Differentiation of tooth and bone tissue was slightly retarded in the clefted fetus but paranasal and oral landmarks, though distorted, were present.

Electron microprobe analysis of human labial gland secretory granules in cystic fibrosis.

X-ray microanalysis of freeze-dried labial gland cryosections revealed that Na concentration was doubled and the Ca/S concentration ratio was decreased in secretory granules of labial glands from patients with cystic fibrosis (CF) when compared with glands from normal subjects. Other results suggested that the decrease in the Ca/S concentration ratio resulted from an increase in S concentration. These findings imply that mucous granules in labial saliva showed a CF-related increase in Na and S content, and such changes would be expected to affect the rheology of the mucus after exocytosis.

Analysis of upper beak defects in chicken embryos following with retinoic acid.

Implanting inert carriers soaked in retinoic acid into the anterior margin of the developing limb of chicken embryos leads to orofacial malformations as well as affecting pattern formation in the limb. Using anion-exchange beads as carriers, and soaking solutions of 1-10 mg/ml retinoic acid, almost 100% of the embryos have malformations of the face. The effects on the treated limbs range from symmetrical patterns of duplicated digits (maximum number of digits being four) to truncations in which no digits were formed at all.

Stage 9 macaque embryos studied by scanning electron microscopy.

Two macaque embryos representing the beginning and the end of stage 9 were studied by scanning electron microscopy. Morphometric evaluation shows that differential growth of head plate elevation, height of the caudal region, width of the head plate and width caudal to the neural groove exceeds embryo elongation, while width of the mid-region, embryonic disc area, width of the embryonic disc, embryo height at the mid-region, length of embryonic disc, and length of the primitive streak undergo relative shrinkage. The head plate becomes topographically subdivided into the three primary segments, while the neural groove narrows, the number of somite pairs increases from one to three, and Hensen's node is obscured.