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Biomedical subjects

R L Searls

Publications and source records attributed to R L Searls.

At least 37 records · Page 2Linked to original sources
PubMed1978

Patterns of cellular proliferation during thyroid organogenesis.

The changes in rate and location of cellular proliferation were analyzed to determine if localized areas of cell division were influencing shape changes in the chick thyroid. Pulse labeling with tritiated thymidine indicates that the gland's labeling index declines throughout its development. Initially, the thyroid placode has a lower labeling index than the neighboring pharyngeal epithelium. An evaluation of the positions of pulse-labeled cells reveals that the evaginating thyroid grows by annexing cells from the pharyngeal epithelium. The older evaginated regions of the gland exhibit the lowest labeling indices. The newly acquired regions still maintain higher labeling indices.

Animals↗
PubMed1976

Effect of dorsal and ventral limb ectoderm on the development of the limb of the embryonic chick.

Limb ectoderm plus a small amount of subjacent mesoderm obtained from the dorsal or the ventral surface of each of the four limbs of the chick embryo were grafted to the dorsal surface of the right wing in either reversed or normal orientation. The host wings developed in abnormal humerus in all cases except when the graft was obtained from the dorsal surface of the right wing and was in normal orientation. However, the nature of the abnormalities varied with the source of the graft and with the orientation of the graft. It is unlikely that the abnormalities were related solely to the small amount of mesoderm grafted since previous experiments have demonstrated that the mesoderm would regulate. Flank ectoderm plus a small amount of flank mesoderm did not cause limb abnormalities when grafted in the same manner.

Animals↗