Analysis of the Proliferation Kinetics of Burkitt's Lymphoma Cells

Abstract

The in vitro proliferation kinetics of a cell line derived from a patient with American Burkitt's lymphoma were investigated at three different growth phases: lag (day 1), exponential (day 3) and plateau (day 5). The growth curve, labeling and mitotic indices, percentage labeled mitosis (PLM) curves and DNA content distributions were determined. The data obtained have been analysed by the previously developed discrete‐time kinetic (DTK) model by which a time course of DNA distributions during a 10‐day growth period was characterized in terms of other cell kinetic parameters. The mean cell cycle times, initially estimated from PLM curves on days 1, 3 and 5, were further analysed by the DTK model of DNA distributions and subsequently the mean cell cycle times with respect to DNA distributions during the entire growth period were determined. The doubling times were 39·6, 31·2 and 67·2 hr, respectively, at days 1, 3 and 5. The mean cell cycle time increased from 23·0 to 37·7 hr from day 3 to day 5 mainly due to an elongation of the G1 and G2 phases. A slight increase in the cell loss rate from 0·0077 to 0·0081 fraction/hr was accompanied by a decrease in the cell production rate from 0·0299 to 0·0184 fraction/hr. This calculated cell loss rate correlated significantly with the number of dead cells determined by trypan blue exclusion. Analysis of the number of dead cells in relation to the cell cycle stage revealed that a majority of cell death occurred in G1 (r= 0·908; P < 0·0001). There was a good correlation between the in vitro proliferation kinetics at plateau phase of this Burkitt's lymphoma derived cell line and the in vivo proliferation kinetics of African Burkitt's lymphoma (Iversen et al., 1974), suggesting the potential utility of information obtained by in vitro kinetic studies.

Development of factors to convert frequency to rate for β-cell replication and apoptosis quantified by time-lapse video microscopy and immunohistochemistry

“…3, if the frequency of Ki67-positive ␤-cells were 1%, we would predict the corresponding rate of ␤-cell mitosis to be 0.025%events/h. These data imply that an average ␤-cell undergoing cell replication is Ki67 positive for ϳ40 h, comparable to the duration observed for other cell types (16,17,19,32,34,39,41). ␤-Cell apoptosis.…”

Epstein-Barr virus latency switch in human B-cells: a physico-chemical model

“…The exact half-life of EBNA-1, τ 1/2 , is not known, but experiments indicate that it is at least 48 hours, probably due to the Gly-Ala repeat domain which inhibits proteasomal degradation [ 44 , 45 ]. In our study we have hence chosen a half-life of 48 hours, and the cell division time is set to be 24 hours [ 46 ]. The model assumes an homogeneous distribution of molecules in the system and does not include spatial movements between different cellular compartments.…”