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Results 501 - 550 of 1774
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Takemura T - - 1999
Although UV is known to induce apoptotic cell death to various animal cells, relationship between cell cycle and UV-induced apoptosis is still unclear. In this study, we investigated the role of G1 phase in UV-induced apoptosis by using EL-4 mouse lymphoma cells which have wild type p53. After 500 J/m2 ...
Stacey D W - - 1999
Levels of Pur alpha, a protein implicated in control of both DNA replication and gene transcription, fluctuate during the cell cycle, being lowest in early S phase and highest just after mitosis. Here we have employed a new video time-lapse technique enabling us to determine the cell cycle position of ...
Kim H D - - 1999
The glucose-regulated stress response of cancer cells leads to a decreased expression of DNA topoisomerase IIalpha (topo IIalpha) and a cell cycle arrest at the G1 phase. In this study, we found that the topo IIalpha decrease occurred specifically during the G1 arrest in human colon adenocarcinoma HT-29 cells. The ...
Zhang X W - - 1999
10-Hydroxycamptothecin (HCPT), a DNA topoisomerase I inhibitor, is an antitumor alkaloid isolated from a Chinese tree, Camptotheca acuminata, and exhibits a remarkable antihepatoma effect. We studied HCPT to determine whether or not its anti-hepatoma activity occurs through apoptosis induction and cell cycle disturbance using the MTT method, DAPI staining, agarose ...
Reil T D - - 1999
BACKGROUND: Experimental studies in vivo have demonstrated that dexamethasone inhibits neointimal hyperplasia following arterial injury. The mechanisms of this inhibition have not been clearly defined. Our objective was to test the hypothesis that dexamethasone directly suppresses smooth muscle cell (SMC) proliferation by inhibiting cell cycle progression and the expression of ...
Schmitz N - - 1999
The protein kinase p34cdc2 is required at the onset of DNA replication and for entry into mitosis. The catalytic subunit and its regulatory proteins, notably the cyclins, are conserved from yeast to man. This suggests that the control mechanisms necessary for progression through the cell cycle in fission yeast are ...
Danaie P - - 1999
The essential cap-binding protein (eIF4E) of Saccharomyces cerevisiae is encoded by the CDC33 (wild-type) gene, originally isolated as a mutant, cdc33-1, which arrests growth in the G1 phase of the cell cycle at 37 degrees C. We show that other cdc33 mutants also arrest in G1. One of the first ...
Chesters J K - - 1999
Zinc has been shown to be required for the passage of cells through the mid-G1 phase of the cell cycle and for differentiation of myoblasts. However, it has been suggested that zinc has other roles during the cell cycle. The experiments reported here indicate that readily available zinc is not ...
de Almeida Engler J - - 1999
Root knot and cyst nematodes induce large multinucleated cells, designated giant cells and syncytia, respectively, in plant roots. We have used molecular markers to study cell cycle progression in these specialized feeding cells. In situ hybridization with two cyclin-dependent kinases and two cyclins showed that these genes were induced very ...
Iwatani Y - - 1999
The change of proliferating cell nuclear antigen (PCNA) expression was examined in three gastric cancer cell lines, MKN28, MKN45 and MKN74, during continuous or bolus exposure to 5-fluorouracil (5-FU). The cytotoxic effect of 5-FU was almost the same in all the cells. PCNA expression was higher at 24 and 72 ...
Yerly-Motta V - - 1999
To obtain different cell populations at specific cell cycle stages, we used a cell culture synchronization protocol. Effects of five different cell cycle inhibitors acting throughout the cell cycle were examined by DNA flow cytometric analysis of a synchrony/release lymphoma cell line (CEM). The screening synchronized protocol showed that staurosporine, ...
Woo E S - - 1999
The dual specificity phosphatase and oncogene Cdc25B has been implicated in the G2/M cell cycle checkpoint, but the mode by which it is regulated remains poorly understood. Regional subcellular redistribution of proteins represents a unique potential regulatory mechanism. Thus, we examined in live cells the subcellular localization characteristics of Cdc25B2 ...
Coffman F D - - 1999
Differentiation of mammalian cells implies cessation of DNA replication and cell proliferation; the potential controls of this coupling are examined here. It is clear that the known or proposed mechanisms of down-regulation of replicative cellular activities vary in different lineages of cell differentiation, and occur in all phases of the ...
González-Beltrán F - - 1999
The difference in efficiency of methylnitrosourea (MNU) and ethylnitrosourea (ENU) to induce SCE in early or late G1 was determined in synchronized murine salivary gland cells in vivo, as a measure of the capacity of this tissue to repair the lesions involved in SCE formation during G1. The repair during ...
Zhang H S - - 1999
Rb inhibits progression from G1 to S phase of the cell cycle. It associates with a number of cellular proteins; however, the nature of these interactions and their relative significance in cell cycle regulation are still unclear. We present evidence that Rb must normally interact with the E2F family of ...
Sveiczer A - - 1999
Fission yeast cells tolerate the total absence of the cdc25 mitotic inducer in two cases, either in cdc2-3w or in wee1 genetic backgrounds. In the cdc2-3w cdc25Delta double mutant, the rate-limiting step leading to mitosis is reaching a critical size. However, the size control of this mutant operates in late ...
Chen M - - 1999
Cell cycle G2 arrest, nuclear localization, and cell death induced by human immunodeficiency virus type 1 Vpr were examined in fission yeast by using a panel of Vpr mutations that have been studied previously in human cells. The effects of the mutations on Vpr functions were highly similar between fission ...
Luo J - - 1999
Animal models have clearly established that ethanol exposure can deplete neurons in the developing nervous system. However, the mechanism by which ethanol reduces cell number is unclear. In our study, cultures of pheochromocytoma cells, a neuronal-like cell line, were maintained in media, which supported cell proliferation. Although cell numbers continued ...
Adesanya O O - - 1999
Insulin-like growth factor 1 (IGF1) has been proposed as a "G1-progression factor" and as a mediator of estradiol's (E2) mitogenic effects on the uterus. To test these hypotheses, we compared E2's mitogenic effects on the uteri of Igf1-targeted gene deletion (null) and wild-type littermate mice. The proportion of uterine cells ...
Buse P - - 1999
The serum- and glucocorticoid-inducible kinase (sgk) is a novel serine/threonine protein kinase that is transcriptionally regulated in rat mammary tumor cells by serum under proliferative conditions or by glucocorticoids that induce a G1 cell cycle arrest. Our results establish that the subcellular distribution of Sgk is under stringent cell cycle ...
Mortimer I - - 1999
Cationic lipid-based delivery systems such as lipoplexes or stabilized plasmid-lipid particles (SPLP) represent a safer alternative to viral systems for gene therapy applications. We studied the impact of cell cycle status on the efficiency of transfection of human ovarian carcinoma tumor cells using two cationic-lipid based delivery systems. Cells arrested ...
Carlson C R - - 1999
Cells of Schizosaccharomyces pombe were grown in minimal medium with different nitrogen sources under steady-state conditions, with doubling times ranging from 2.5 to 14 hours. Flow cytometry and fluorescence microscopy confirmed earlier findings that at rapid growth rates, the G1 phase was short and cell separation occurred at the end ...
Jacobberger J W - - 1999
BACKGROUND: Flow cytometry of immunofluorescence and DNA content provides measures of cell-cycle-related gene expression (protein and/or epitope levels) for asynchronously growing cells. From these data, time-related expression through S phase can be directly measured. However, for G1, G2, and M phases, this information is unavailable. We present an objective method ...
David Goodall,Keith Burston
This report presents the medium access control (MAC) scheme designed for supporting synchronous traffic within the AMNET LAN. Synchronous traffic is supported directly at the MAC layer via a table mechanism, and is carried by two different types of cell - synchronous cells, which carry data from a single transmitter, ...
Barboule N - - 1999
Activation of protein kinase C (PKC) inhibits cell cycle progression at the G1/S and G2/M transitions. We found that phorbol 12-myristate 13-acetate (PMA) induced upregulation of p21, not only in MCF-7 cells arrested in the G1 phase as previously shown, but also in cells delayed in the G2 phase. This ...
Zicha D - - 1999
We have previously shown that addition of type 1 transforming growth factor-beta (TGFbeta1) to an exponentially growing population of mink lung CCl64 cells increases their average intermitotic time from 14.4 to 20.3 hours, predominantly by extending G1 from 7.5 to 13.5 hours. Here we have used the DRIMAPS system (digitally ...
Moynihan E B - - 1999
Ribonucleotide reductase activity is required for generating deoxyribonucleotides for DNA replication. Schizosaccharomyces pombe cells lacking ribonucleotide reductase activity arrest during S phase of the cell cycle. In a screen for hydroxyurea-sensitive mutants in S. pombe, we have identified a gene, liz1(+), which when mutated reveals an additional, previously undescribed role ...
Karst S M - - 1999
Retroviruses and retrotransposons depend on their host cells to complete their replication cycles. In many cases, the viral step of reverse transcription is blocked when host cells are arrested in their cell cycle and this block is only released when the host cell resumes division. It has previously been shown ...
Zamanian-Daryoush M - - 1999
The interferon (IFN)-induced, double stranded RNA (dsRNA)-activated serine/threonine kinase, PKR, is a potent negative regulator of cell growth when overexpressed in yeast or mammalian cells. To determine whether endogenous PKR plays a role in cell growth control, we have investigated the regulation of PKR levels and activity during the cell ...
Xu C X - - 1999
Howiinol A (GHM-10) is a kind of phenylethylene pyrone compounds isolated from Goniothalamus howii. By using the techniques of cell growth curve determination, MTT test, soft agar colony assay and experimental therapy of transplantable tumors in mice, it is found that GHM-10 exerts potent inhibitory effect on cancer cells but ...
Lu M - - 1999
Earlier studies have revealed that human cytomegalovirus rapidly inhibits the growth of fibroblasts, blocking cell cycle progression at multiple points, including the G1-to-S-phase transition. The present study demonstrates that the UL69 protein, a virus-encoded constituent of the virion, is able to arrest cell cycle progression when introduced into uninfected cells. ...
Prather R S - - 1999
One of the major points of debate in determining the effectiveness of nuclear transfer technology has been the phase of the cell cycle of the donor cell at the time of nuclear transfer. Here, a primary mammary cell line has been isolated and various treatments for synchronization of the cell ...
Boydston-White S - - 1999
Infrared spectra of myeloid leukemia (ML-1) cells are reported for cells derived from an asynchronous, exponentially growing culture, as well as for cells that were fractionated according to their stage within the cell division cycle. The observed results suggest that the cells' DNA is detectable by infrared spectroscopy mainly when ...
Rigberg D A - - 1999
Introduction. The p21 cyclin-dependent kinase inhibitor arrests the cell cycle following DNA damage at the G1-S checkpoint. Recent literature has also demonstrated a role for p21 in G2 arrest. Studies with esophageal squamous cell carcinoma (ESSC) lines have shown that radiation-induced p21 protein induction is associated with G2 arrest. The ...
Chou L F - - 1999
Three different types of cells were synchronized by various methods and DNA-end binding (DEB) activities of Ku were compared with asynchronous controls. In CHO K1 cells synchronized in G1 phase by serum starvation and in S phase by serum refeeding, DEB activity was reduced in S cells but remained unchanged ...
Yu F - - 1999
Characteristics of the cell cycle in cortical regions (0-0.6 mm from the root-cap junction) of the primary root of lentil (Lens culinaris L.) during germination in the vertical position on earth were determined by iododeoxyuridine labelling and image analysis. All cells were in the G1 phase at the beginning of ...
Lamprecht J - - 1999
We examined the effects of lovastatin, a common anti-atherosclerotic drug and a blocker of the cell cycle, on the process of mitosis. It is known that lovastatin induces an arrest or a retardation of the cell cycle in many cell types not only at the G(1)phase, but also at the ...
Bonneton C - - 1999
The NBT-II rat bladder carcinoma cell line, which displays epithelial to mesenchymal transition or EMT in response to FGF-1 stimulation, was used to study the interrelationships between cell cycle and cell scattering and locomotion. Time-lapse video microscopy experiments were performed with asynchronous growing cells and lovastatin-arrested cells. FGF-1 stimulation induced ...
Nagata T - - 1999
Synchronous cell systems are highly desirable for investigating various aspects of plant cell biology. However, to date, the tobacco BY-2 cell line is the only plant cell line which can be synchronized to high levels. A cell synchrony starting from S phase is obtained after release of BY-2 cells from ...
Yamaguchi T - - 1999
Vpr, one of the accessory molecules of HIV-1, has been demonstrated to arrest the cell cycle at the G2 phase. This Vpr-mediated cell cycle arrest is implicated to have an important role in the viral life cycle. In the present study, we quantitate the extent of Vpr-mediated cell cycle arrest ...
Yoo Y D - - 1998
Paclitaxel induces a cell cycle block at G2-M phase by preventing the depolymerization of microtubules and induces p53-independent apoptosis in many cancer cells. We observed that gastric cancer cells treated with paclitaxel have shown a cyclin-dependent kinase (CDK)4 down-regulation. This paclitaxel-induced CDK4 down-regulation resulted in a cell cycle arrest at ...
Hayashi T - - 1998
Our purpose is to evaluate at which phase of the cell cycle CA 125 is dominantly expressed in a uterine cervical adenocarcinoma cell line (CAC-1). By a flow cytometric analysis of CA 125 expression, approximately 50% of the cells treated with interferon-gamma (IFN) were positive after 24 h. In cell ...
Xu Z - - 1998
In eukaryotic cells, checkpoint pathways arrest cell-cycle progression if a particular event has failed to complete appropriately or if an important intracellular structure is defective or damaged. Saccharomyces cerevisiae strains that lack the SFP1 gene fail to arrest at the G2 DNA-damage checkpoint in response to genomic injury, but maintain ...
Galli A - - 1998
A wide variety of carcinogens including Ames assay (Salmonella) positive as well as Salmonella negative carcinogens induce intrachromosomal recombination (DEL recombination) in Saccharomyces cerevisiae. We have shown previously that the Salmonella positive carcinogens, ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS) and 4-Nitroquinoline-N-oxide (4-NQO, and the Salmonella negative carcinogens, safrole, benzene, thiourea, ...
Hwang A - - 1998
Exposure of mammalian cells to X rays results in prolongation of the cell cycle, including delays or arrests in G1, S and G2 phase. While G1-phase arrest occurs only in cells with wild-type p53 function, a G2-phase delay occurs in all cells regardless of p53 status. In this review, we ...
Juan G - - 1998
Expression of pRb and its state of phosphorylation were immunocytochemically assayed in individual HL-60 cells during their proliferation and after induction of differentiation, using mAb which detects hypophosphorylated pRb (pRbP-) combined with mAb which reacts with pRb regardless of its phosphorylation (total pRb; pRbT). Correlated measurements of pRbP-, pRbT, a ...
Lefresne J - - 1998
After fertilization in axolotl, the synchronous cell cleavages are triphasic (S, G2 and M phases). Midblastula transition (MBT) begins at the ninth cleavage and is the consequence of lengthening of cell cycles. By spectrofluorometry and incorporation of 3H thymidine into the nuclear DNA followed by autoradiography on individual cells, the ...
Beck E P - - 1998
The antigenic determinant CA 125 is a high molecular weight glycoprotein which is elevated in more than 80% of patients with epithelial ovarian cancer. Despite its good performance as a human tumor marker, only little is known about its physiological function. According to recent publications, CA 125 production and release ...
Koritzinsky M - - 1998
PURPOSE: To investigate whether radiation survival of cells irradiated aerobically in the oxygen-sensitive restriction point in late G1 is dependent on where in the cell cycle the cells first were rendered hypoxic. MATERIALS AND METHODS: Human cervix carcinoma, NHIK 3025 cells, were synchronized and rendered hypoxic while in early-, mid- ...
Nishi K - - 1998
The staurosporine-induced G1 cell cycle arrest was analyzed in a variety of cell lines which includes human tumor cell lines and oncogene-transformed NIH3T3 cell lines. All the cell lines which were sensitive to staurosporine-induced G1 arrest contained a functional retinoblastoma protein (pRB). However, when pRB-lacking fibroblast cells derived from pRB ...
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