Search Results
Results 601 - 650 of 1774
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Planas-Silva M D - - 1997
Research over the past two decades has defined a window of time in the early/mid G1 phase of the cell cycle during which mammalian cells are responsive to extracellular signals. Recent evidence indicates that this period ends with the phosphorylation of the retinoblastoma protein, enabling the cells to pass through ...
Lam M H - - 1997
Parathyroid hormone-related protein (PTHrP) is highly expressed in normal skin keratinocytes, and its involvement in growth and differentiation processes in these cells has been implicated by several lines of evidence which include the use of antisense PTHrP (Kaiser et al., 1994, Mol. Endocrinol., 8:139-147). In this study, we have investigated ...
Comayras C - - 1997
Cytolethal distending toxins (CDT) constitute an emerging heterogeneous family of bacterial toxins whose common biological property is to inhibit the proliferation of cells in culture by blocking their cycle at G2/M phase. In this study, we investigated the molecular mechanisms underlying the block caused by CDT from Escherichia coli on ...
Lin S - - 1997
We previously identified and characterized the human leukemia (HL-60) cell DNA synthetic machinery as a multiprotein form of DNA polymerase, which was designated the DNA synthesome. This multiprotein replication complex contains DNA polymerases alpha and delta, primase, replication factor C, replication protein A, helicase, poly(ADPribose) polymerase, proliferating cell nuclear antigen, ...
Lotfi C F - - 1997
The adrenocorticotropic hormone (ACTH) inhibits the growth of Y1 mouse adrenocortical tumor cells as well as normal adrenocortical cells in culture but stimulates adrenocortical cell growth in vivo. In this study, we investigated this paradoxical effect of ACTH on cell proliferation in Y1 adrenal cells and have unmasked a growth-promoting ...
Salone B - - 1997
The effect of X-irradiation (1 Gy) during G1 on the transition from G1 to S and on the length of G2 over cell cycles subsequent to irradiation was studied in human lymphocytes from six different donors. After irradiation a delay was observed in the onset of S phase, as was ...
Martel J - - 1997
The response of T cells in relation to the cell cycle has not been extensively studied. We have attempted to address this question using Jurkat T cells treated with cytostatic drugs known to arrest cells at various transition points of their cycle. We tested several concentrations of drugs that act ...
Ueno T - - 1997
Apoptotic cell death of murine leukemia cells induced by E. coli L-asparaginase was studied. Deprivation of L-asparagine from the culture of L5178Y cells by L-asparaginase caused the fragmentation of chromosomal DNA of the leukemia cells within 24 h. Prior to the degradation of DNA, cell cycles of L5178Y cells were ...
Fernandes P M - - 1997
Little is known about the mechanisms by which nutrient limitation leads to G1 arrest in Saccharomyces cerevisiae. We have shown that mutant cells deleted in the trehalose-6-phosphate synthase gene able to grow on glucose, when starved for nitrogen, did not arrest in the G1 phase of the cell cycle. We ...
Sun B - - 1997
Protein kinase C (PKC) is activated at the nucleus during the G2 phase of cell cycle, where it is required for mitosis. However, the mechanisms controlling cell cycle-dependent activation of nuclear PKC are not known. We now report that nuclear levels of the major physiologic PKC activator diacylglycerol (DAG) fluctuate ...
Ullrich N - - 1997
We recently demonstrated expression of a novel, glioma-specific Cl- current in glial-derived tumor cells (gliomas), including stable cell lines such as STTG1, derived from a human anaplastic astrocytoma. We used STTG1 cells to study whether glioma Cl- channel (GCC) activity is regulated during cell cycle progression. Cells were arrested in ...
Shugart E C - - 1997
The clonal expansion phase of 3T3-L1 adipose conversion is a distinct mitotic period during which the initiation of differentiation occurs concomitant with a discrete set of mitotic divisions. During clonal expansion, a cocktail of adipogenic hormones, including the glucocorticoid dexamethasone, induced 3T3-L1 cells to progress from postconfluent adipoblasts to postmitotic ...
Bacon C L - - 1997
The influence of valproate on in vitro glycosylation events in C6 glioma has been investigated, as this major human teratogen restricts proliferation in the mid-G1 phase of the cycle and alters the prevalence and/or glycosylation state of cell surface glycoproteins with the potential to mediate cell-cell and cell matrix interactions ...
Bittman K - - 1997
Cells within the ventricular zone (VZ) of developing neocortex are coupled together into clusters by gap junction channels. The specific role of clustering in cortical neurogenesis is unknown; however, clustering provides a means for spatially restricted local interactions between subsets of precursors and other cells within the VZ. In the ...
Johnson N F - - 1997
DNA damage induced by chemicals and ionizing radiation is associated with the expression of negative regulators of the cell cycle. The arrest of cells in G1 and G2 phases of the cell cycle provides time for DNA repair. Asbestos fibers are carcinogenic when inhaled by both humans and animals; however, ...
Lillibridge C D - - 1997
Increased levels of cytokines in the salivary glands have been associated with the loss of secretory cells and reduced salivary function. It has been demonstrated that interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) treatment of a human submandibular gland (HSG) cell line causes growth arrest in the G0/G1 phase of ...
Sackey F N - - 1997
The human leukemic cell line (CCRF-CEM) and a subline enriched for the plasma membrane-resident glucocorticoid receptor (mGR) were studied for the influence of the cell cycle on the expression and function of mGR. Three synchronization procedures (double thymidine, colcemid, and combined thymidine-colcemid blocks) were used. Fluorescent microscopy and flow cytometry ...
Guthridge M A - - 1997
We have identified a novel type 2C serine-threonine phosphatase, FIN13, whose expression is induced by fibroblast growth factor 4 and serum in late G1 phase. The protein encoded by FIN13 cDNA includes N- and C-terminal domains with significant homologies to type 2C phosphatases, a domain homologous to collagen, and an ...
Ogryzko V V - - 1997
We have analyzed the effects on HeLa cells of reduction of the CAS protein, the human homologue to yeast chromosome segregation protein CSE1. Expression of CAS antisense cDNA decreases the amount of CAS protein in HeLa cells and perturbs progression from G2 (retards transition from G2) to G1 in the ...
Gadbois D M - - 1997
Epithelial cells along the conducting airways can be more or less continuously exposed to DNA-damaging agents, which should limit their proliferation by inducing cell cycle checkpoints. Yet, paradoxically, airway epithelial cells frequently show a hyperplastic response when exposed to such agents. In this in vitro study, we assessed the hypothesis ...
Brooks S C SC - - 1997
NB4, a human acute promyelocytic leukemia cell line expressing the promyelocyte-retinoic acid receptor alpha (PML-RAR alpha) hybrid protein was treated with RAR- and retinoid X receptor (RXR)-selective analogs to determine their effects on cell proliferation, retinoblastoma (RB) tumor-suppressor protein phosphorylation, and differentiation. An RAR- or just RAR alpha-selective analog alone ...
Wu J R - - 1997
At a distinct point during G1 phase (the origin decision point [ODP]), Chinese hamster ovary (CHO) cell nuclei experience a transition (origin choice) that is required for specific recognition of the dihydrofolate reductase (DHFR) origin locus by Xenopus egg extracts. We have investigated the relationship between the ODP and progression ...
Swe M - - 1997
Staurosporine is a protein kinase inhibitor that is known to block G1/S and G2/M cell cycle transitions, resulting in the accumulation of G1 or G2 interphase cells, depending on the applied dosage. It is, however, not known to block mitosis (M-phase) progression. We show here that a 15 min prepulse ...
Linke S P - - 1997
This study analyses whether the inability of p53 to induce G1 arrest after the restriction point relates to an inability to modulate pRb phosphorylation. Transient p53 overexpression in normal human diploid fibroblasts and p53-deficient cancer cells led to increased levels of the cyclin-dependent kinase inhibitor p21 cip1/Waf1/Sdi1 and an accumulation ...
Ruffner H - - 1997
We have characterized the BRCA1 gene product by using four polyclonal antibodies raised against peptides from four different regions of the protein. The antibodies specifically recognize an approximately 220-kDa BRCA1 protein that is predominantly expressed in the nucleus of both normal and neoplastic breast cancer cells. It is a serine ...
Buquet-Fagot C - - 1997
We have studied the effects of olomoucine, a selective inhibitor of cdk2, cdc2 and MAP kinase, on the rate of proliferation and the cell cycle progression in human cancer cells in culture. Olomoucine inhibited the growth of the KB 3-1, MDA-MB-231 and Evsa-T cell lines in a concentration-dependent manner, with ...
Yonaha M - - 1997
In this report, cell-cycle-dependent effects of TFIID on other basal transcription factors were investigated. We purified TFIID fractions from HeLa cells synchronized in the S/G2 phases and in early G1 phase, and show that RAP74 is phosphorylated more highly by the S/G2 phase TFIID fraction than by the early G1 ...
Puntoni F - - 1997
The retinoblastoma gene product (pRb) is dephosphorylated at the exit from mitosis and protein phosphatase-1 (PP1) seems to be responsible for such dephosphorylation. Three isoforms of PP1 exist in mammalian cells, alpha, gamma1 and delta, with differential subcellular localization and potentially different targeting subunits and functions. In order to identify ...
Kwon T K - - 1997
Polyclonal activation of murine G0 T cells with immobilized anti-CD3 induces entry into the cell cycle as well as the subsequent cytokine-dependent proliferative response. G0 T cells express high levels of p27Kip1 protein and specific mRNA, which decline rapidly following activation. The decline in the expression of p27Kip1 and sequestering ...
Hildebrand B - - 1997
Glial progenitors strongly express the proenkephalin (PEnk) gene during their proliferation in the subventricular zone of the neocortex. Also in primary culture, astroglial cells from rat neocortex produce PEnk mRNA. Since the basal expression sharply declines after the cultured cells reach confluence, it seems to be related to cell proliferation. ...
Sirri V - - 1997
To know the biological basis allowing the use of Ag-NOR protein expression as proliferation marker in human malignancies, the relationship between cell cycle and amount of Ag-NOR protein was analyzed. The quantification of the two major Ag-NOR proteins, nucleolin and protein B23, was performed in exponentially growing, serum-deprived, and cell-cycle ...
Johnson N F - - 1997
A biodosimetric approach to determine alpha-particle dose to the respiratory tract epithelium from known exposures to radon has been developed in the rat. Cytotoxicity assays have been used to obtain dose-conversion factors for cumulative exposures typical of those encountered by underground uranium miners. However, this approach is not sensitive enough ...
Powlin S S - - 1997
Cadmium (Cd), the heavy metal, is toxic to the placenta. The objectives of this study were to determine if Cd toxicity is due to inhibition of placental or trophoblast cell proliferation through interactions with the intracellular calcium binding protein, calmodulin (CaM). Cd can replace calcium and thus interfere with CaM's ...
Wang S C - - 1997
It has been shown that genetic alterations in BRCA1 and BRCA2 can predispose an individual to develop breast cancer. We investigated the expression of both BRCA2 and BRCA1 during the progression of the cell cycle by northern blot analysis. In MCF-10F (normal breast epithelial cell line) and MCF-7 (breast cancer ...
Gerenday A - - 1997
We have established conditions for use of hydroxyurea, a reversible inhibitor of DNA synthesis, to synchronize the division cycle of a continuous cell line from the mosquito, Aedes albopictus. In the range of 0.15-0.25 mM hydroxyurea, an 18 h treatment, followed by removal of the drug, results in effective synchronization. ...
Poon B - - 1997
The product of the human immunodeficiency virus type 1 (HIV-1) vpr gene induces cell cycle arrest in the G2 phase of the cell cycle and is characterized by an accumulation of the hyperphosphorylated form of cdc2 kinase. This phenotype is similar to the effect of DNA-damaging agents, which can also ...
Bergé J P - - 1997
An organic extract of the marine diatom Skeletonema costatum was studied in vitro for its effect on asynchronous cells of a human non-small-cell bronchoplumanory carcinoma line (NSCLC-N6). Cell growth appeared to be inhibited in the G1 phase of the cell cycle, and kinetic studies in pretreated cells showed that this ...
Freemerman A J - - 1997
The p21MDA6 gene product induces cell cycle arrest in p53-null human leukemic cells exposed to differentiation stimuli. We employed an HL-60 cell line stably transfected with a p21MDA6 antisense construct to compare the effects of p21MDA6 dysregulation on the response of myeloid leukemia cells to differentiating and cytotoxic agents. Antisense-expressing ...
Sarkar R - - 1997
We characterized the cell cycle block induced by nitric oxide (NO) on smooth muscle cells (SMC). We hypothesized that the inhibition of SMC proliferation by NO was due to a specific block in cell cycle progression. Treatment of cultured rat aortic SMC with the NO donors S-nitroso-N-acetylpenicillamine or S-nitrosoglutathione (0.1 ...
Shinomiya N - - 1997
Caffeine overrides checkpoints in the G2 phase of the cell cycle by inhibiting DNA repair at this phase and increases the cytotoxicity of antitumor drugs, such as cis-diamminedichloroplatinum (CDDP). The enhanced cell death induced by caffeine is characterized by apoptosis. In this paper, we demonstrate that this apoptotic event occurs ...
Machl A W - - 1997
Retroviral vectors are effective shuttle systems by introducing therapeutically relevant genes stably into the genome of proliferating cells. The majority of vectors applied for research or clinical applications use neomycin for cell selection and identification. To circumvent the time consuming and potentially toxic G418 selection process in transduction studies we ...
Tagawa Y - - 1997
We studied differences in chromatin patterns and the spatial localization of centromeres of chromosome 11 during the cell cycle between normal peripheral blood lymphocytes (PBL) and human promyelocytic leukemia cells (HL-60) using fluorescence in situ hybridization. The pericentromeres in both cells were located at the periphery during Gq (quiescent) phase, ...
Nishino Y - - 1997
Human immunodeficiency virus type 1 Vpr is a 96-amino-acid virion-associated protein that arrests cells in the G2 phase of the cell cycle in peripheral blood lymphocytes, HeLa, 293, 293T, A549, Jurkat, CEM, SupT1, CV-1 and COS1 cells. When we transfected Vpr expression vector into mouse NIH3T3 and then cultured it ...
O'Rourke J - - 1997
CCAAT/enhancer binding proteins (C/EBPs) are a highly conserved family of DNA-binding proteins that regulate cell growth and differentiation in a highly tissue-specific manner. These experiments investigated the influence of the cell cycle on C/EBP isoform expression in mammary epithelial cells (COMMA D) and fibroblasts (NIH3T3). C/EBP-delta gene expression is induced ...
Miller A M - - 1997
The cell line M-07e requires either Interleukin-3 (IL-3) or granulocyte-macrophage colony stimulating factor (GM-CSF) for proliferation in vitro. Cells deprived of growth factor for up to 48 hours remain viable but no longer divide. The growth-factor-deprived M-07e cells begin to divide within 48 hours of reexposure to IL-3. Flow cytometric ...
Brunner S - - 1997
We have employed a newly developed differential screening technique (reverse strand priming) to identify murine carnitine acetyltransferase (CARAT) as a growth- and cell cycle-regulated gene in S3T3 mouse fibroblasts. Sequence analysis of the full-length cDNA clone and homology comparisons have revealed 87% homology to the human CARAT gene. On Northern ...
Kawasaki M - - 1997
We have demonstrated a method for the in situ determination of the cell cycle phases of TIG-7 fibroblasts using a laser scanning cytometer (LSC) which has not only a function equivalent to flow cytometry (FCM) but also has a capability unique in itself. LSC allows a more detailed analysis of ...
Fukushima K - - 1997
Synchronized cultures of rat 3Y1 cells, prepared by the density-arrested method, were used to investigate the relationship of N-glycosylation to the cell cycle. Although total cellular proteins were synthesized independently of the cell cycle, the synthesis of membrane-bound proteins was found to be dependent on the cell cycle, the time ...
Mikami K - - 1997
To study the cytophysiological effects of ethanol systematically, L929 cells, a fibroblastic cell line derived from mouse connective tissue, were exposed to various concentrations of ethanol (12.5, 50, 100 and 200 mM) for short (3 and 6 h) and longer (24 or 26 h) durations. Ethanol-induced cellular responses were analysed ...
Zoidl G - - 1997
The peripheral myelin gene PMP22 is the rat and human homologue of the murine growth-arrest-specific gene gas3. The biological function of PMP22 is unknown, but recent progress in the analysis of rat Schwann cells expressing altered levels of PMP22 revealed that one role of PMP22 is as a negative growth ...
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