Punctuated cell cycling in the regeneration blastema of urodele amphibians

Tomlinson, Bruce L.; Goldhamer, David J.; Barger, Philip M.; Tassava, Roy A.

doi:10.1111/j.1432-0436.1985.tb00824.x

Cited by 21 publications

(21 citation statements)

References 26 publications

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“…The proportion of cycling cells in the S phase can be determined as the labeling index (LI) observed following a brief (2 h or pulse) exposure to [3H]-T. Assuming all blastema cells are randomly distributed and progressing toward their next mitotic division, the pulse-labeling index can be compared to the predicted labeling index, the formula: predicted LI = (length of S/length of the total cell cycle) x 100 [40]. The proportion of cycling cells in the S phase can be determined as the labeling index (LI) observed following a brief (2 h or pulse) exposure to [3H]-T. Assuming all blastema cells are randomly distributed and progressing toward their next mitotic division, the pulse-labeling index can be compared to the predicted labeling index, the formula: predicted LI = (length of S/length of the total cell cycle) x 100 [40].…”

Section: B Evaluation Of the Pc-hypothesis Parametersmentioning

confidence: 99%

“…The proportion of cycling cells in the S phase can be determined as the labeling index (LI) observed following a brief (2 h or pulse) exposure to [3H]-T. Assuming all blastema cells are randomly distributed and progressing toward their next mitotic division, the pulse-labeling index can be compared to the predicted labeling index, the formula: predicted LI = (length of S/length of the total cell cycle) x 100 [40]. Individual values for each of these terms were obtained from previously reported estimates of S and the total cell-cycle times observed in Ambystoma regenerates [40], and averages were calculated from these individual values. The proportion of actively cycling cells can then be estimated from the pulse-labeling index using the formula: AC=Pulse LI (length of the cell cycle/length of S).…”

Section: B Evaluation Of the Pc-hypothesis Parametersmentioning

confidence: 99%

“…Additional cell-cycle parameters outlined in the punctuated-cycling hypothesis [40] were determined by evaluating the labeling indices following continuous [3H]-T labeling. Due to the extended length of s, repeated injections of [3H]-T at 12-h intervals represent a form of continuous labeling [l, 9,401.…”

Section: B Evaluation Of the Pc-hypothesis Parametersmentioning

confidence: 99%

“…Assuming that all blastema cells are actively cycling and randomly distributed about the cell cycle, a labeling index of 75%-80% would be predicted for axolotl blastemata [40] (see Methods). Assuming that all blastema cells are actively cycling and randomly distributed about the cell cycle, a labeling index of 75%-80% would be predicted for axolotl blastemata [40] (see Methods).…”

Section: Isotope Dose and Incorporation Periodmentioning

confidence: 99%

“…In populations of cycling cells, continuous labeling with tritiated thymidine ([3H]-T) may be used to identify the proliferative fraction (Po and subdivide it into actively cycling (AC) and transiently quiescent (TQ) subpopulations [40]. By comparison, short-term or pulse labeling with [3H]-T identifies only the proportion of cells that are currently participating in the S phase of the cell cycle, and this value may be used to estimate the size of the actively cycling population; however, it does not provide any information about cells that may be quiescent or nonproliferative (nonPf).…”

Section: Introductionmentioning

confidence: 99%

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A test of the punctuated-cycling hypothesis in Ambystoma forelimb regenerates: the roles of animal size, limb innervation, and the aneurogenic condition

Tomlinson

Barger

1987

Differentiation

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Section: B Evaluation Of the Pc-hypothesis Parametersmentioning

confidence: 99%

“…The proportion of cycling cells in the S phase can be determined as the labeling index (LI) observed following a brief (2 h or pulse) exposure to [3H]-T. Assuming all blastema cells are randomly distributed and progressing toward their next mitotic division, the pulse-labeling index can be compared to the predicted labeling index, the formula: predicted LI = (length of S/length of the total cell cycle) x 100 [40]. Individual values for each of these terms were obtained from previously reported estimates of S and the total cell-cycle times observed in Ambystoma regenerates [40], and averages were calculated from these individual values. The proportion of actively cycling cells can then be estimated from the pulse-labeling index using the formula: AC=Pulse LI (length of the cell cycle/length of S).…”

Section: B Evaluation Of the Pc-hypothesis Parametersmentioning

confidence: 99%

Section: B Evaluation Of the Pc-hypothesis Parametersmentioning

confidence: 99%

Section: Isotope Dose and Incorporation Periodmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A test of the punctuated-cycling hypothesis in Ambystoma forelimb regenerates: the roles of animal size, limb innervation, and the aneurogenic condition

Tomlinson

Barger

1987

Differentiation

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Denervation‐induced changes in cell proliferation in the rat molar after wounding

et al. 1986

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The dental pulp has the capacity to initiate and maintain repair after trauma. The purpose of the present study was to quantitatively analyze the role of the peripheral nervous system in regulation of pulpal cell proliferation in response to wounding. Six groups of ten rats were used in these studies. There was one baseline group (wounded, but innervation intact) and five resection groups. The resection groups included rats with unilateral superior cervical ganglionectomy (SCG), unilateral inferior alveolar nerve resection (IAN), unilateral chorda tympani (CT) resection, IAN + SCG, or a complete unilateral nerve resection (IAN + SCG + CT). One millimeter of enamel and dentin was removed from the first mandibular molar on the experimental (resected) side. Therefore, each rat had an experimental and control molar. Rats were killed at various intervals from day 0 to day 15 after wounding and received 0.5 muCi/g b.wt. 3H-thymidine 1 hour before death. For the baseline (innervation intact) data a peak in 3H-thymidine incorporation occurred at 5 days after wounding. In the resected groups, there was a general increase in the number of labeled cells at the zero time point, and a suppression of the 5-day peak with a delay in the proliferative response to wounding. The SCG + IAN-resected group maintained the lowest number of labeled cells throughout the entire experimental period compared to the experimental baseline data and the two controls. At the initial and termination points the SCG + IAN-resected groups demonstrated the highest number of labeled cells.(ABSTRACT TRUNCATED AT 250 WORDS)

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Pattern‐deficient forelimb regeneration in adult bullfrogs

Tomlinson

Tassava

1985

J. Exp. Zool.

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This study was designed to test the ability of adult bullfrogs (Rana catesbeiana) to regenerate forelimbs, both with and without various experimental treatments. Distal humerus-level forelimb amputations provided with additional deviated (sciatic) nerve and/or repeated soft-tissue injury exhibited considerable outgrowth. However, control sham-operated forelimbs also produced regenerates with comparable frequency, size, and morphological complexity. The lengths of the regenerates ranged from 0.4 to 2.6 cm, representing an outgrowth of 10-65% of the portion removed by the distal humerus amputation plane; some regenerates exhibited an external morphology indicative of digitlike structures. Some outgrowths were flexible but only one was capable of independent movement. Victoria Blue staining of whole regenerates revealed a variety of internal cartilage elements. Staining showed a single solid mass of cartilage in some regenerates while others had several individual and variably shaped cartilages projecting distally. Histological analysis also revealed the presence of connective tissue, striated muscle, and abundant nerve fibers in addition to the individual cartilage elements. We have tentatively termed these responses pattern-deficient regeneration.

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Punctuated cell cycling in the regeneration blastema of urodele amphibians

Cited by 21 publications

References 26 publications

A test of the punctuated-cycling hypothesis in Ambystoma forelimb regenerates: the roles of animal size, limb innervation, and the aneurogenic condition

A test of the punctuated-cycling hypothesis in Ambystoma forelimb regenerates: the roles of animal size, limb innervation, and the aneurogenic condition

Denervation‐induced changes in cell proliferation in the rat molar after wounding

Pattern‐deficient forelimb regeneration in adult bullfrogs

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