Cytokinetic Analysis at Various Ages of an Ascites Tumor after Radiation

1978 ◽  
Vol 64 (5) ◽  
pp. 463-470
Author(s):  
Eva Siracká ◽  
Natasa Pappová
Keyword(s):  
Cell Cycle ◽  
Growth Rate ◽  
Cycle Time ◽  
Doubling Time ◽  
Cell Loss ◽  
Whole Body ◽  
Ascites Tumor ◽  
Cell Cycle Time ◽  
Slowing Down ◽  
Proliferative Phase

A cytokinetic analysis has been made of 5-day and of 10-day old murine 6C3HED ascites lymphosarcoma (Gardner) by using a growth curve, percentage of labeled mitoses curves, and continuous labeling curves. The doubling time increased from 36 h in the proliferative phase of growth to 252 h in the stationary phase. The slowing down of the growth rate was due to prolongation of the cell cycle time, with greatest extension in G1 and increased cell loss. The measurement of the kinetic parameters made immediately after irradiation with a whole-body single dose of 3 Gy (300 rad) showed an increase in duration of the cell cycle in the 5-day-old tumor, while in the 10-day-old tumor the cell cycle time was decreased due to reduce length in the G1 phase.

Review of basic concepts of cell kinetics as applied to brain tumors

1975 ◽  
Vol 42 (2) ◽  
pp. 123-131 ◽  
Author(s):  
Takao Hoshino ◽  
Charles B. Wilson
Keyword(s):  
Cell Cycle ◽  
Brain Tumors ◽  
Cycle Time ◽  
Doubling Time ◽  
Cell Kinetics ◽  
Cell Loss ◽  
Growth Fraction ◽  
Cell Cycle Time ◽  
Tumor Doubling Time ◽  
Basic Concepts

✓ The authors review and discuss the basic concepts of cell kinetics as applied to brain tumors. Uncontrolled growth of a neoplasm represents an expanding tumor cell population. Four growth parameters characterize the behavior of a neoplastic population: cell cycle time, growth fraction, tumor doubling time, and cell loss. The concept of provisionally nondividing cells explains the disparity between cell cycle time and tumor doubling time. Human gliomas, like many non-neural solid tumors, contain variable proportions of actively proliferating and nonproliferating tumor cells; this ratio is expressed by the growth fraction. The major kinetic difference between glioblastomas and differentiated astrocytomas resides in their respective growth fractions, in all likelihood an inherent biological characteristic of each tumor. Glioblastoma proliferates at a rapid rate, and only a high rate of cell loss prevents this tumor from doubling its volume in less than 1 week. The selection of drugs and design of drug schedules for treatment of glioblastomas should be made with the knowledge that 60% to 70% of the cells in this tumor are resting (nonproliferating). If experience with other solid tumors is any guide, judicious selection and combined use of drugs according to kinetically sound schedules will produce more effective chemotherapy of brain tumors.

Estimation of growth fraction with bromodeoxyuridine in human central nervous system tumors

1986 ◽  
Vol 65 (5) ◽  
pp. 659-663 ◽  
Author(s):  
Yoshihiko Yoshii ◽  
Yutaka Maki ◽  
Koji Tsuboi ◽  
Yuji Tomono ◽  
Kunio Nakagawa ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cycle Time ◽  
Doubling Time ◽  
Malignant Gliomas ◽  
Cell Loss ◽  
Growth Fraction ◽  
Cell Cycle Time ◽  
Tumor Doubling Time ◽  
Content Type ◽  
Fine Print

✓ Twenty-five patients with tumors of the central nervous system received bromodeoxyuridine (BUdR), 200 mg/sq m, by intravenous infusion every 8 hours for 3 days before surgery. Excised tumor specimens were fixed in chilled 70% ethanol, embedded in paraffin, and cut into 6-µm sections. Each section was reacted with monoclonal antibodies against BUdR and stained with immunoperoxidase to identify nuclei that had incorporated BUdR. The growth fraction of each tumor was estimated by calculating the ratio of BUdR-positive nuclei to the total number of tumor cells in three to six microscopic fields in viable areas of the tumor. In seven cases, the tumor doubling time was measured from the serial computerized tomography scans and an attempt was made to estimate the cell cycle time. The growth fractions ranged from 9.1% to 46.5% in malignant gliomas, 2.0% to 6.7% in low-grade gliomas, 11.2% to 43.2% in metastatic brain tumors, 0.8% to 1.9% in pituitary adenomas, 3.9% to 4.6% in acoustic neurinomas, and 6.2% to 8.2% in meningiomas and cerebellar hemangioblastomas. The estimated cell cycle time was 5 to 12 days in most malignant gliomas and brain metastases; however, the actual cell cycle time should be substantially shorter because cell loss was not considered in the calculation. Although the growth fraction appeared to correlate with the biological malignancy of each tumor, the tumor doubling time did not reflect growth potential. It is possible that unpredictable cell loss plays an important role in tumor growth at certain sizes. Therefore, the cell cycle times calculated in this study are considerably overestimated and should be interpreted with caution.

Tissue economics of hydra: regulation of cell cycle, animal size and development by controlled feeding rates

1977 ◽  
Vol 28 (1) ◽  
pp. 117-132
Author(s):  
J.J. Otto ◽  
R.D. Campbell
Keyword(s):  
Cell Cycle ◽  
Steady State ◽  
Epithelial Cell ◽  
Cycle Time ◽  
Cell Loss ◽  
Tissue Growth ◽  
Tissue Loss ◽  
Feeding Rates ◽  
Cell Cycle Time ◽  
Steady State Condition

Epithelial cell production and epithelial cell loss in 6 different size classes of Hydra attenuata were examined to understand the relationships between growth and morphogenesis. The sizes of adult hydra, the sizes of their buds, and their budding rates are all nearly proportional to the amount of food the hydra eat. Hydra fed at high rates (4-25 Artemia nauplii per day) all have the same epithelial cell cycle time (about 4 days). Budding accounts for most of their cell loss. Hydra fed 4–12 Artemia per day maintain a steady state condition in which tissue loss balances tissue growth. Animals fed 25 Artemia per day are not in a steady state growth condition and change in size. At the lowest feeding rates (0-1 Artemia per day), the epithelial cell cycle time is lengthened to about 16 days. Cell loss from the tentacles accounts for most of the cell loss, and this loss is not completely balanced by growth. As a consequence these animals cease budding and shrink in size.

Nuclear DNA content and minimum generation time in herbaceous plants

1972 ◽  
Vol 181 (1063) ◽  
pp. 109-135 ◽  
Keyword(s):  
Cell Cycle ◽  
Dna Content ◽  
Cycle Time ◽  
Generation Time ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Annual Species ◽  
Cell Cycle Time ◽  
Developmental Processes ◽  
The Mean

Many components of cell and nuclear size and mass are correlated with nuclear DNA content in plants, as also are the durations and rates of such developmental processes as mitosis and meiosis. It is suggested that the multiple effects of the mass of nuclear DNA which affect all cells and apply throughout the life of the plant can together determine the minimum generation time for each species. The durations of mitosis and of meiosis are both positively correlated with nuclear DNA content and, therefore, species with a short minimum generation time might be expected to have a shorter mean cell cycle time and mean meiotic duration, and a lower mean nuclear DNA content, than species with a long mean minimum generation time. In tests of this hypothesis, using data collated from the literature, it is shown that the mean cell cycle time and the mean meiotic duration in annual species is significantly shorter than in perennial species. Furthermore, the mean nuclear DNA content of annual species is significantly lower than for perennial species both in dicotyledons and monocotyledons. Ephemeral species have a significantly lower mean nuclear DNA content than annual species. Among perennial monocotyledons the mean nuclear DNA content of species which can complete a life cycle within one year (facultative perennials) is significantly lower than the mean nuclear DNA content of those which cannot (obligate perennials). However, the mean nuclear DNA content of facultative perennials does not differ significantly from the mean for annual species. It is suggested that the effects of nuclear DNA content on the duration of developmental processes are most obvious during its determinant stages, and that the largest effects of nuclear DNA mass are expressed at times when development is slowest, for instance, during meiosis or at low temperature. It has been suggested that DNA influences development in two ways, directly through its informational content, and indirectly by the physical-mechanical effects of its mass. The term 'nucleotype' is used to describe those conditions of the nucleus which effect the phenotype independently of the informational content of the DNA. It is suggested that cell cycle time, meiotic duration, and minimum generation time are determined by the nucleotype. In addition, it may be that satellite DNA is significant in its nucleotypic effects on developmental processes.

The Cell Cycle Time In Intestinal Crypts By Simulation of Flm Experiments

1988 ◽  
Vol 21 (6) ◽  
pp. 429-436 ◽  
Author(s):  
H. P. Meinzer ◽  
W. Chen ◽  
B. Sandblad ◽  
N. Wright
Keyword(s):  
Cell Cycle ◽  
Cycle Time ◽  
Cell Cycle Time
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