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Results 451 - 500 of 1770
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Lehman J M - - 2000
The infection of permissive monkey kidney cells (CV-1) with simian virus 40 induces G1 growth-arrested cells into the cell cycle. After completion of the first S phase and movement into G2, mitosis was blocked and the cells entered another DNA synthesis cycle (second S phase). Growth-arrested CV-1 cells replicated significant ...
Suzuki A - - 2000
Survivin is observed uniquely in tumor cells and developmental cells, which undergo either inappropriate or programmed cell growth. In the current study, we investigated the influence of Survivin on cell cycle. Overexpression of Survivin resulted in accelerated S phase shift, resistance to G1 arrest, and activated Cdk2/Cyclin E complex leading ...
Elder R T - - 2000
HIV-1 Vpr induces cell cycle G2 arrest, morphological changes and cell death in human and fission yeast cells. The cellular targets for G2 arrest were expected to be the inhibitory phosphorylation sites of Cdc2, as G2 arrest correlates with hyperphosphorylation and decreased activity of Cdc2 in both human and fission ...
Reil T D - - 2000
We have previously demonstrated that dexamethasone (DEX) suppresses neointimal hyperplasia and proliferation of rat aortic smooth muscle cells (SMC) by inducing a late G1 phase cell cycle arrest. Phosphorylation of retinoblastoma protein (Rb) regulates cell proliferation by controlling progression from G1 to S phase of the cell cycle. We hypothesized ...
Franchitto A - - 2000
PURPOSE: To investigate whether catalytic topoisomerase II activity by ICRF187, a compound that interferes with the catalytic cycle of topoisomerase II without causing DNA damage, could result in a modulation of X-ray-induced chromosomal damage in Werner's syndrome (WS) cell lines. MATERIALS AND METHODS: Two WS (KO375, DJG) and one normal ...
den Boer B G - - 2000
In essence, the mitotic cell cycle in eukaryotes involves the duplication and separation of chromosomes, coupled to the process of dividing one cell into two. Cytokinesis is therefore the culmination of a series of events that were triggered during G1 phase, and brings the daughter cells back to the starting ...
Dutertre S - - 2000
Bloom's syndrome (BS) is a rare human autosomal recessive disorder characterized by an increased risk to develop cancer of all types. BS cells are characterized by a generalized genetic instability including a high level of sister chromatid exchanges. BS arises through mutations in both alleles of the BLM gene which ...
Escalas N - - 2000
HeLa cells exposed to Escherichia coli cytolethal distending toxins (CDT) arrest their cell cycle at the G2/M transition. We have shown previously that in these cells the CDK1/cyclin B complex is inactive and can be reactivated in vitro using recombinant CDC25 phosphatase. Here we have investigated in vivo the effects ...
Gong H - - 2000
L-Asparaginase is used for the treatment of acute leukemias, but is sometimes ineffective or associated with severe side-effects. We report here that the enzyme arginine deiminase is approximately 100-fold more potent than L-asparaginase in inhibiting the proliferation of cultured human lymphatic leukemia cell lines while it appears to be less ...
Pichierri P - - 2000
Werner's syndrome (WS) is a rare autosomal recessive human disorder and the patients exhibit many symptoms of accelerated ageing in their early adulthood. The gene (WRN) responsible for WS has been biochemically characterised as a 3'-5' helicase and is homologous to a number of RecQ superfamily of helicases. The yeast ...
De Rycke J - - 2000
The bacterial cytolethal distending toxin (CDT) was previously shown to block the cell cycle of several cell lines at stage G2 through inactivation of the cyclin-dependent kinase Cdkl and without induction of DNA strand breaks. In the present study, we have analyzed, using various methods of analytical cytometry, the progressive ...
Yokoyama Y - - 2000
delta 12-PGJ2, one of the cyclopentenone prostaglandins and the ultimate metabolite of prostaglandin D2, has been reported to have potent antiproliferative activity on various tumor cells in vitro and in vivo. In this study, the combined effect of delta 12-PGJ2 and hyperthermia on six established cell lines of human esophageal ...
Drut R - - 2000
Villous stroma nucleomegalic cells harbouring intracytoplasmic parasites are an unusual finding which appears to be restricted to Chagas' disease placentitis. Ploidy analysis of these cells in two cases (twelve nuclei in Case 1 and 26 in Case 2) showed these nuclei to contain quantitatively abnormal DNA. Only a few were ...
Valenzuela M T - - 2000
BACKGROUND AND PURPOSE: We have investigated whether the protective role of the G2 checkpoint has increasing importance when the p53-dependent G1 checkpoint is inactivated. MATERIALS AND METHODS: We have studied the differential effect of caffeine by clonogenic assays and flow cytometry in three human tumour cell lines with different functionality ...
Su T T - - 2000
BACKGROUND: Studies in unicellular systems have established that DNA damage by irradiation invokes a checkpoint that acts to stall cell division. During metazoan development, the modulation of cell division by checkpoints must occur in the context of gastrulation, differential gene expression and changes in cell cycle regulation. To understand the ...
Kues W A - - 2000
The success of somatic nuclear transfer critically depends on the cell cycle stage of the donor nucleus and the recipient cytoplast. In this study we tested serum deprivation as well as two reversible cell cycle inhibitors, aphidicolin and butyrolactone I, for their ability to synchronize porcine fetal fibroblasts at either ...
Martín-Castellanos C - - 2000
Eukaryotic cells coordinate cell size with cell division by regulating the length of the G1 and G2 phases of the cell cycle. In fission yeast, the length of the G1 phase depends on a precise balance between levels of positive (cig1, cig2, puc1, and cdc13 cyclins) and negative (rum1 and ...
Parmar J - - 2000
Cell cultures exposed to DNA-damaging agents such as gamma radiation respond by arresting at cell cycle checkpoints, and the p53 tumor suppressor protein is strongly implicated in this behavior. We have investigated the TP53 status and cell cycle response to ionizing radiation of a series of early passage cell lines ...
Sasaki Y - - 2000
Abnormal cell cycle regulation is believed to be an important step in tumorigenesis. In mammalian cells, DNA damage commonly leads to cell cycle arrest in G2; however, little is known about the detailed biochemical mechanisms underlying the DNA damage-induced G2 arrest. In order to identify genes differentially expressed in association ...
Aherne S A - - 2000
In the present study the effects of three flavonoids on the repair of H2O2-induced DNA strand breaks were investigated in Caco-2, Hep G2, and V79 cells. At the concentrations used, myricetin, quercetin, rutin, and H2O2 did not significantly affect cell viability in all the cell lines. Catalase activity was measured ...
Hwang H S - - 2000
Recent studies of fluoropyrimidine (FP)-mediated radiosensitization (RS) have focused on the molecular mechanisms underlying regulation of the cell cycle, particularly at the G1-S transition. Although thymidylate synthase (TS) inhibition by FP is necessary, we hypothesize that FP-RS is temporally dependent on progression of cells into S-phase under conditions of altered ...
Kim W H - - 2000
Ceramide is known to induce pRb (retinoblastoma gene product) dephosphorylation through the activation of ceramide-activated protein phosphatase (CAPP) during G1 arrest, but other molecular mechanisms linked to regulation of pRb dephosphorylation during ceramide-induced G1 arrest are poorly understood. In this paper, we investigated whether p21, a cdk (cyclin-dependent kinase) inhibitor, ...
Perugini R A - - 2000
The mutations most common in pancreatic cancer decrease the ability to control G1 to S cell cycle progression and cellular proliferation. In colorectal cancer cells, nonsteroidal anti-inflammatory drugs inhibit proliferation and induce cell cycle arrest. We examined whether sodium salicylate, an aspirin metabolite, could inhibit proliferation in human pancreatic cancer ...
Chen C H - - 2000
This study has demonstrated that baicalein has anticancer effectiveness against human hepatoma cells. The dose response of baicalein in Hep G2 and Hep J2 cells indicates that baicalein decreased viability >90%. In comparison, baicalein had only minimal effects on the viability of control Chang liver cells. Flow cytometric analysis showed ...
Ivanovska I - - 2000
Saccharomyces cerevisiae cells decide to divide during G1. If nutrients are abundant, cells pass through START and coordinately undergo DNA replication, bud emergence, and spindle pole body duplication. Phenotypic analysis of the slg1delta mutant revealed that this mutation uncouples post-START events. At the nonpermissive temperature, slg1delta cells that have undergone ...
Toy E P - - 2000
OBJECTIVE: To determine the ability of the human immunodeficiency virus type 1 (HIV-1) gene vpr to induce cell-cycle arrest in cervical cancer cells with or without human papillomavirus (HPV) type 16 E6 or E7 expression. METHODS: High- and low-level expression vectors for vpr (designated pVPR(HIGH) and pVPR(LOW), respectively) were used ...
Brown G - - 1999
1alpha,25-Dihydroxyvitamin D(3) (D(3)) provokes growth arrest and monocytic differentiation in myeloid cells. Although it is usually assumed that the cellular events leading to growth arrest start within one cell cycle of D(3) addition, there is also evidence that D(3) provokes the expression of proliferation-related genes and accelerates cell division. Herein ...
Zong Z P - - 1999
Staurosporine has been reported to cause arrest of cells in G1 phase at low concentration and in G2 phase at high concentration. This raises the question of why the effects of staurosporine on the cell cycle depend on the applied concentration. In order to verify these multiple functions of staurosporine ...
Kato J - - 1999
The first gap phase (G1) in the mammalian cell cycle plays a pivotal role in determining whether or not cells are to initiate DNA replication. Progression through G1 phase and transition into S phase are positively and negatively regulated by a series of factors, collectively termed G1 regulators. Among them, ...
Siu W Y - - 1999
Cell cycle arrest after different types of DNA damage can occur in either G1 phase or G2 phase of the cell cycle, involving the distinct mechanisms of p53/p21(Cip1/Waf1) induction, and phosphorylation of Cdc2, respectively. Treatment of asynchronously growing Swiss3T3 cells with the chemotherapeutic drug adriamycin induced a predominantly G2 cell ...
Sert V - - 1999
The bacterial cytolethal distending toxin (CDT) was previously shown to arrest the tumor-derived HeLa cell line in the G2-phase of the cell cycle through inactivation of CDK1, a cyclin-dependent kinase whose state of activation determines entry into mitosis. We have analysed the effects induced in HeLa cells by CDT, in ...
Mason B - - 1999
There is experimental and epidemiological evidence that antioxidant vitamins can inhibit carcinogenesis. Since immortalization by Human Papilloma Virus (HPV) is one possible early step towards carcinogenesis in oral epithelia, we studied the differential effect of vitamins A, C and E on HPV-immortalized oral epithelial cells (IHGK) as compared to the ...
Bastians H - - 1999
The ubiquitin-dependent proteolysis of mitotic cyclin B, which is catalyzed by the anaphase-promoting complex/cyclosome (APC/C) and ubiquitin-conjugating enzyme H10 (UbcH10), begins around the time of the metaphase-anaphase transition and continues through G1 phase of the next cell cycle. We have used cell-free systems from mammalian somatic cells collected at different ...
Marti A - - 1999
Papovavirus tumour antigens have been widely used to study cell growth regulation in cultured cells. We investigated the role of mouse polyomavirus T antigens, small-, middle- and large-T, in stimulating growth-arrested REF52 fibroblasts to enter the S phase. Microinjecting cells with cDNAs encoding the various T antigens showed: first, that ...
Frost S J - - 1999
Recent studies have shown that methylation of the CpG island within the p16/CDKN2A gene is associated with an absence of p16 protein in human pituitary tumors. However, the effect of restoration of p16 protein expression in this tumor type has not been investigated. In the absence of an available human ...
Hill A A - - 1999
PURPOSE: To determine radiosensitivity as a function of cell age (the age-response) in three human tumour cell lines, and investigate the dependence of the age-response on G1 arrest and on cell-age heterogeneity in synchronized cell populations. MATERIALS AND METHODS: Variation in radiosensitivity throughout the cell cycle and G1 arrest was ...
Chan T A - - 1999
14-3-3Sigma is a member of a family of proteins that regulate cellular activity by binding and sequestering phosphorylated proteins. It has been suggested that 14-3-3sigma promotes pre-mitotic cell-cycle arrest following DNA damage, and that its expression can be controlled by the p53 tumour suppressor gene. Here we describe an improved ...
Chen X - - 1999
In this study we investigated the growth inhibitory effects of UCN-01 in several normal and tumor-derived human breast epithelial cells. We found that while normal mammary epithelial cells w were very sensitive to UCN-01 with an IC(50) of 10nM tumor cells displayed little to no inhibition of growth with any ...
Fan H - - 1999
Stratified epithelium displays an equilibrium between proliferation and cell cycle arrest, a balance that is disrupted in basal cell carcinoma (BCC). Sonic hedgehog (Shh) pathway activation appears sufficient to induce BCC, however, the way it does so is unknown. Shh-induced epidermal hyperplasia is accompanied by continued cell proliferation in normally ...
Li C - - 1999
In this study, a green fluorescent protein (GFP)-calmodulin (CaM) fusion gene method was used to examine the distribution of calmodulin during various stages of cell cycle. First, it was found that the distribution of CaM in living cells changes with the cell cycle. CaM was found mainly in the cytoplasm ...
Dimitrijevic-Bussod M - - 1999
It is thought that sublethal doses of radiation cause cells to pause in either G1 or G2 phase, but that then cells with repaired DNA damage reenter the cell cycle. However, it has been observed that gamma-irradiation causes normal human fibroblasts to arrest indefinitely in G1 phase unless the irradiated ...
Chen X - - 1999
In this study we investigated the growth inhibitory effects of UCN-01 in several normal and tumor-derived human breast epithelial cells. We found that while normal mammary epithelial cells were very sensitive to UCN-01 with an IC50 of 10 nM, tumor cells displayed little to no inhibition of growth with any ...
Ehsan H - - 1999
In animal systems, indomethacin inhibits cAMP production via a prostaglandin-adenylyl cyclase pathway. To examine the possibility that a similar mechanism occurs in plants, the effect of indomethacin on the cell cycle of a tobacco bright yellow 2 (TBY-2) cell suspension was studied. Application of indomethacin during mitosis did not interfere ...
Taniguchi K - - 1999
OBJECT: The enzyme DNA topoisomerase IIalpha (Topo IIalpha) was tested as a measure of cell proliferation in gliomas. METHODS: Immunostaining for the Topo IIalpha and for the Ki-67 antigen (MIB-1 antibody) was performed in paraffin-embedded tissue sections obtained from 25 resected human gliomas. Additionally, cultured human glioma cells were subjected ...
Robles S J - - 1999
Damage to DNA has been implicated in the induction of permanent cell cycle arrest or premature senescence in normal human fibroblasts. We tested the ability of a group of cancer chemotherapeutic agents or related compounds, which can cause DNA double-strand breaks (DSBs) directly or indirectly, to induce a permanent cell ...
Karlsson C - - 1999
We have used time-lapse fluorescence microscopy to study the properties of the Cdc25B and Cdc25C phosphatases that have both been implicated as initiators of mitosis in human cells. To differentiate between the functions of the two proteins, we have microinjected expression constructs encoding Cdc25B or Cdc25C or their GFP-chimeras into ...
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 ...
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