The uptake of tritiated thymidine by human amnion cells: a correlation with cell structure

1968 ◽  
Vol 14 (7) ◽  
pp. 791-797
Author(s):  
S. B. Hrushovetz ◽  
J. C. Wilt ◽  
E. S. C. Lee
Keyword(s):  
Cell Cycle ◽  
Incubation Period ◽  
Cell Population ◽  
Hela Cells ◽  
Tritiated Thymidine ◽  
Cell Structure ◽  
Human Amnion ◽  
Proliferative Phase ◽  
Mitotic Figures ◽  
Continuous Labelling

It was found that less than 1% of amnion cells, either as membrane biopsies, as trypsinized cell suspensions, or grown as monolayers on glass incorporated tritiated thymidine during a 1-hour incubation period; this was in contrast to HeLa cells in which over 30% of the cell population incorporated tritiated thymidine. Continuous labelling with tritiated thymidine for a 24-hour period with or without colchicine failed to increase the percentage of labelled amnion cells, while a minimum of 80% of the HeLa cells became labelled. Less than 0.1% of the amnion cells were in mitosis, compared to 4% for HeLa cells. Incubation with colchicine for 24 hours failed to increase the percentage of mitotic figures of the amnion cells. It is concluded that most of the primary amnion cells are in the non-proliferative phase of the cell cycle.

scholarly journals Effect of cell population density on G2 arrest in Tetrahymena.

1975 ◽  
Vol 67 (3) ◽  
pp. 518-522 ◽  
Author(s):  
I L Cameron ◽  
N C Bols
Keyword(s):  
Cell Cycle ◽  
Population Density ◽  
Cell Population ◽  
Tritiated Thymidine ◽  
Tetrahymena Pyriformis ◽  
High Cell ◽  
Ciliated Protozoan ◽  
G2 Phase ◽  
Cell Densities ◽  
Two Peaks

The ciliated protozoan, Tetrahymena pyriformis strain GL-C, has been used to study the effect of cell population density during starvation on the synchrony obtained after refeeding and on the number of cells arrested in G2 phase of the cell cycle. At high cell densities two peaks of division indices were observed after refeeding while only one was observed at low cell densities. Cell division began earlier in cultures starved at high cell densities. Most importantly, the proportion of cells in G2 was considerably higher in populations starved at high cell densities. When tritiated thymidine was present during the refeeding period, radioautographs of cell samples at different times showed that the first cells to exhibit division furrows contained unlabeled nuclei. The first peak in the division index after refeeding was observed only at higher cell densities and is attributed to the cells arrested in G2. These results suggest that Tetrahymena is an excellent organism to study the concept of resting stages in the cell cycle and their control.

The neural cell cycle in the looptail (Lp ) mutant mouse

Development ◽  
1974 ◽  
Vol 32 (3) ◽  
pp. 697-705
Author(s):  
Doris B. Wilson ◽  
E. M. Center
Keyword(s):  
Cell Cycle ◽  
Early Development ◽  
Generation Time ◽  
Mutant Mouse ◽  
Tritiated Thymidine ◽  
Neural Cell ◽  
Abnormal Development ◽  
Ventricular Cells ◽  
The Difference ◽  
Mitotic Figures

The cell cycle of mesencephalic ventricular cells was studied by means of tritiated thymidine radioautography during normal and abnormal development in the looptail (Lp ) mutant mouse. The total generation time, DNA-synthetic (S), premitotic (G2), mitotic (M), and postmitotic (G1) periods were compared in looptail homozygotes (Lp/Lp ) which exhibit neural dysraphism and in their normal littermates (+ / +) at 10 and 11 days ’ gestation. Both normal and abnormal embryos showed a chronological lengthening of the generation time between the 10th and 11th day. However, the generation time in the 10-day abnormal brains was 4·5 h longer than that in normal littermates, and the difference was the result of an increase mainly in the M and G1 periods. At 11 days of gestation the generation time in the abnormal brains increased by 50 h over that of the normal brains. Since the cell cycle was actually prolonged in the defective brains, the increased numbers of mitotic figures which characterize the looptail homozygote brain during early development appear to reflect the lengthening of the mitotic period rather than increased proliferation.

scholarly journals CELL POPULATION KINETICS OF EXCISED ROOTS OF PISUM SATIVUM

1965 ◽  
Vol 27 (1) ◽  
pp. 179-189 ◽  
Author(s):  
Jack Van't Hof
Keyword(s):  
Cell Population ◽  
Mitotic Cycle ◽  
Sucrose Concentration ◽  
Tritiated Thymidine ◽  
Cycle Duration ◽  
Population Kinetics ◽  
Pea Roots ◽  
Mitotic Figures ◽  
Kinetics Of ◽  
Subsequent Rise

The cell population kinetics of excised, cultured pea roots was studied with the use of tritiated thymidine and colchicine to determine (1) the influence of excision, (2) the influence of sucrose concentration, (3) the average mitotic cycle duration, and (4) the duration of mitosis and the G1, S, and G2 periods of interphase.1 The results indicate that the process of excision causes a drop in the frequency of mitotic figures when performed either at the beginning of the culture period or after 100 hours in culture. This initial decrease in frequency of cell division is independent of sucrose concentration, but the subsequent rise in frequency of division, after 12 hours in culture, is dependent upon sucrose concentration. Two per cent sucrose maintains the shortest mitotic cycle duration. The use of colchicine indicated an average cycle duration of 20 hours, whereas the use of tritiated thymidine produced an average cycle duration of 17 hours.

EFFECT OF DEXAMETHASONE ON CELL POPULATION KINETICS IN THE ADRENAL CORTEX OF THE PREPUBERTAL MALE RAT

1974 ◽  
Vol 62 (3) ◽  
pp. 527-536 ◽  
Author(s):  
N. A. WRIGHT ◽  
D. R. APPLETON ◽  
A. R. MORLEY
Keyword(s):  
Cell Cycle ◽  
Latent Period ◽  
Adrenal Cortex ◽  
Direct Action ◽  
Tritiated Thymidine ◽  
Labelling Index ◽  
Male Rats ◽  
Male Rat ◽  
Rate Of Increase ◽  
Continuous Labelling

SUMMARY The effect of a single injection of dexamethasone on adrenocortical cell proliferation was studied in prepubertal male rats using tritiated thymidine. After a short latent period, all zones of the adrenal cortex showed a rapid decrease in both labelling and mitotic indices. After a prolonged period when very low indices were apparent, there was a rapid rise in both proliferative indices with most zones showing a considerable increase above control values. A more detailed study of the initial depression showed that after a latent period of about 5 h the labelling index fell approximately 8 h before the mitotic index. This differential response in the labelling and mitotic indices was consistent with a block in the cell cycle late in the pre-DNA synthetic interval of the cell cycle (G1), with cells being prevented from entering DNA synthesis. This hypothesis was also supported by an experiment involving continuous labelling of control and dexamethasone-treated animals; again after a latent period of 5–6 h, the rate of increase of the continuous labelling index fell as cells became blocked in late G1. By analogy with other tissues, results are interpreted in terms of a direct action of dexamethasone on adrenocortical cells; this steroid-sensitive step in the cell cycle may be important in the control of growth in the adrenal cortex.

scholarly journals Apoptotic effect of novel pyrazolone-based derivative [Cu(PMPP-SAL)(EtOH)] on HeLa cells and its mechanism

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Delizhaer Reheman ◽  
Jing Zhao ◽  
Shan Guan ◽  
Guan-Cheng Xu ◽  
Yi-Jie Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cervical Cancer ◽  
Hela Cells ◽  
Copper Complexes ◽  
Antibacterial Properties ◽  
Inhibitory Effect ◽  
Parp Cleavage ◽  
Potential Candidate ◽  
Tnf Α

Abstract Pyrazolone complexes have strong anti-tumor and antibacterial properties, but the anti-tumor mechanism of pyrazolone-based copper complexes has not been fully understood. In this study, the possible mechanism and the inhibitory effect of a novel pyrazolone-based derivative compound [Cu(PMPP-SAL)(EtOH)] on human cervical cancer cells (HeLa cells) was investigated. [Cu(PMPP-SAL)(EtOH)] effectively inhibited proliferation of HeLa cells in vitro with an IC50 value of 2.082 after treatment for 72 h. Cell cycle analysis showed apoptosis was induced by blocking the cell cycle in the S phase. [Cu(PMPP-SAL)(EtOH)] promoted the loss of mitochondrial membrane potential, release of cytochrome c, PARP cleavage, and activation of caspase-3/9 in HeLa cells. Additionally, [Cu(PMPP-SAL)(EtOH)] inhibited the PI3K/AKT pathway and activated the P38/MAPK, and JNK/MAPK pathways. [Cu(PMPP-SAL)(EtOH)] also inhibited the phosphorylation of Iκ-Bα in the NF-κB pathway activated by TNF-α, thus restricting the proliferation of HeLa cells which were activated by TNF-α. In conclusion, [Cu(PMPP-SAL)(EtOH)] inhibited the growth of HeLa cells and induced apoptosis possibly via the caspase-dependent mitochondria-mediated pathway. These results suggest that [Cu(PMPP-SAL)(EtOH)] can be a potential candidate for the treatment of cervical cancer.

In vitro evidence that LHRH stimulates the recruitment of prolactin mRNA-expressing cells during the postnatal period in the rat

1994 ◽  
Vol 12 (1) ◽  
pp. 107-118 ◽  
Author(s):  
A Van Bael ◽  
R Huygen ◽  
B Himpens ◽  
C Denef
Keyword(s):  
Cell Cycle ◽  
Cell Population ◽  
Blot Hybridization ◽  
Postnatal Period ◽  
S Phase ◽  
Female Rats ◽  
Mrna Levels ◽  
Dot Blot ◽  
Total Cell Population

ABSTRACT We have studied the effect of LHRH and neuropeptide Y (NPY) on prolactin (PRL) mRNA levels in pituitary reaggregate cell cultures from 14-day-old female rats, by means of in situ hybridization and Northern blot analysis. As estimated by computer-image analysis, addition of LHRH on day 5 in culture for 40 h resulted in a 37% increase in the total cytoplasmic areas of cells containing PRL mRNA, visualized using a digoxigenin-labelled PRL cRNA. The size of individual PRL-expressing cells was not influenced, nor was the content of PRL mRNA per cell. A similar effect of LHRH was found by dot blot hybridization of extracted RNA. PRL mRNA levels were not affected by NPY. LHRH induced a 29% increase in the number of PRL mRNA-expressing cells processing through the S phase of the cell cycle, visualized by the incorporation of [3H]thymidine ([3H]T) into DNA over 16 h. The fraction of [3H]T-labelled cells was 10–12% of the total cell population. NPY did not influence the number of [3H]T-positive cells expressing PRL mRNA, but completely blocked the effect of LHRH on the latter population. The present data suggest that LHRH, probably via a paracrine action of gonadotrophs, stimulates the recruitment of new lactotrophs, an action which is negatively modulated by NPY. Since the magnitude of this effect was the same in the total pituitary cell population as in cells processing through the S phase of the cell cycle and presumably mitosis, recruitment of lactotrophs seems to be based on differentiation of progenitor or immature cells into PRL-expressing cells, rather than on a mitogenic action on pre-existing lactotrophs alone.

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