The relation of mitotic index, cell density, and growth to pattern regulation in regeneratingAmbystoma maculatum forelimbs
✍ Scribed by Stocum, David L.
- Publisher
- John Wiley and Sons
- Year
- 1980
- Tongue
- English
- Weight
- 786 KB
- Volume
- 212
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
Mitotic index and cell density were determined for all stages of larval Ambystoma maculatum upper arm and wrist regeneration up to the notch. Intrinsic growth rates and proportions of skeletal segments of upper arm and wrist regenerates were determined for stages of regeneration from notch to 25 days post‐amputation. Mitotic index was always higher in the blastema of the regenerate than in the dedifferentiating tissue proximal to it. Mitotic activity along the proximal‐distal axis of the blastema proper was relatively uniform until the onset of redifferentiation, when it declined in a distal to proximal direction in the proximal half of the blastema. Cell density tended to parallel mitotic index in both wrist and upper arm regenerates. There was no evidence that apical growth of the blastema is controlled by an inverse relationship between cell density (contact inhibition) and mitotic index. The relationship between the intrinsic growth rates of the regenerating skeletal segments were such that the proportions of the segments remained unchanged throughout their redifferentiation in upper arm regenerates, but were shifted slightly in wrist regenerates. These findings are discussed in relation to the progress zone model of limb development (Summerbell et al., '73).