In vitro incorporation of tritiated thymidine in oral homogeneous leukoplakias

Abstract

– The rate of cell proliferation in homogeneous leukoplakias was compared with that of normal mucosa. Biopsies from six patients were labeled in vitro with tritiated thymidine and the labeling indices relative to (1) the total cell population, (2) the progenitor compartment, and (3) 100 μm surface length, were determined on autoradiographs. In leukoplakias, cell renewal and mitotic cycles were faster than in the epithelium of controls.

Epithelial cell kinetics in oral leukoplakia

“…Our results support the data presented by ALVARES et al (9) who first reported a preliminary comparison of the labelling index of homogeneous leukoplakia with clinically normal buccal mucosa. The rise in labelling index observed in our study from 3.39% in the clinically normal buccal mucosa to 6.1% in leukoplakias is comparable to the labelling index values documented by these authors (2.72%) in normal, 4.74% in leukoplakia).…”

“…The rise in labelling index observed in our study from 3.39% in the clinically normal buccal mucosa to 6.1% in leukoplakias is comparable to the labelling index values documented by these authors (2.72%) in normal, 4.74% in leukoplakia). The degree of increase in cell proliferation observed (1.77 fold) is almost equivalent to that which can be estimated from the results of ALVARES et al (9) (1.78 fold). Data examined by all four reference indices demonstrated the same change, suggesting that the rise in LI was not a reflection of any concurrent changes in the reference units.…”

“…Data examined by all four reference indices demonstrated the same change, suggesting that the rise in LI was not a reflection of any concurrent changes in the reference units. One of the objections to in vitro labelling is the inconsistency of labelhng throughout the specimen (9,17). By the use of 1 mm mucosal slices in labelling experiments, we obtained uniform labelling with the exception of edge effects which were avoided during counting.…”

“…Using the latter method, labelling index (LI) values for normal human buccal epithelium have been estimated (8). Studies of the relationship of altered morphology in keratotic oral lesions to cell kinetics are limited (9,10). Our aims were to derive the labelling index of oral leukoplakia and to estimate the duration of the S-phase of the cell cycle in order to assess if any correlation existed between the degree of epithelial dyspiasia and the cell kinetics of the tissue.…”

The phenotype of persons having mosaicism for trisomy 21/Down syndrome reflects the percentage of trisomic cells present in different tissues

“…In one of the few reports detailing the kinetics of normal lymphocytes and buccal epithelia, Hellerstein et al [1999] noted that, in healthy individuals, CD4 and CD8 T cells have a half-life of approximately 87 and 77 days, respectively. In contrast, the turnover times seen in buccal epithelial cells have been reported to vary from 5 to 25 days [Gillespie, 1969; Alvares et al, 1972]. Collectively, the findings of these two studies suggest that lymphocytes have a lower turnover rate than buccal cells.…”