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Results 601 - 650 of 1495
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Scorcioni F - - 2001
We have previously reported that cyclical phases of accumulation and depletion of polyamines occur during cell-cycle progression. Regulatory ornithine decarboxylase (ODC) catalyses the first step of polyamine biosynthesis. Ornithine decarboxylase antizyme (OAZ), induced by high polyamine levels, inhibits ODC activity and prevents extracellular polyamine uptake. Spermidine/spermine N1-acetyltransferase (SSAT) regulates the ...
Reddy V K - - 2001
From the results of our previous physicochemical studies of polyamine-nucleic acid interactions, we concluded that polyamine analogues in cisoidal conformation are capable of wrapping around the major groove of the double helix, of displacing natural polyamines from their nucleic acid binding sites, and of inhibiting cell division. On the basis ...
Fajardo I - - 2001
The effects of histamine on polyamine uptake and metabolism was studied in a mouse mast cell line (C57.1), as a cell model in which both biogenic amines are important for maintaining cell function and viability. Results obtained after incubations with exogenous histamine indicated that histamine prevents polyamine accumulation by affecting ...
Pietschmann T - - 2001
Subgenomic selectable RNAs of the hepatitis C virus (HCV) have recently been shown to self-replicate to high levels in the human hepatoma cell line Huh-7 (V. Lohmann, F. Körner, J. O. Koch, U. Herian, L. Theilmann, and R. Bartenschlager, Science 285:110-113, 1999). Taking advantage of this cell culture system that ...
Korhonen V P - - 2001
Polyamines are known to be essential for normal cell growth and differentiation. However, despite numerous studies, specific cellular functions of polyamines in general and individual polyamines in particular have remained only tentative, because of a lack of appropriate cell lines in which genes of polyamine-synthesizing enzymes have been disrupted by ...
SawiƄski P - - 2001
Molecular biology techniques help to study details of testicular cell interactions, which play an important role in the control of spermatogenesis and secretory function of the male gonad. This paper presents an example of application of such techniques, with evaluation of their usability, in the study on expression of some ...
Duchrow M - - 2001
The human antigen defined by the monoclonal antibody Ki-67 (pKi-67) is a human nuclear protein strongly associated with cell proliferation and found in all tissues studied. It is widely used as a marker of proliferating cells, yet its function is unknown. To investigate its function we suppressed pKi-67 expression by ...
Vujcic S - - 2000
Acetylation of polyamines by spermidine/spermine N(1)-acetyltransferase (SSAT) has been implicated in their degradation and/or export out of the cell. The relationship of SSAT to polyamine pool dynamics and cell growth is not yet clearly understood. MCF-7 human breast carcinoma cells were transfected with tetracycline-regulated (Tet-off) SSAT human cDNA or murine ...
Bergamini G - - 2000
In eukaryotic cells, efficient translation of most cellular mRNAs requires the synergistic interplay between the m7GpppN cap structure and the poly(A) tail during initiation. We have developed and characterized a cell-free system from human HeLa cells that recapitulates this important feature, displaying more than one order of magnitude of translational ...
Klegeris A - - 2000
R-(-)-Deprenyl (deprenyl, selegiline), a monoamine oxidase B (MAO-B) inhibitor, delays progression of Parkinson's disease. This action could be mediated by inhibition of MAO-B but there may also be unrelated mechanisms. Direct neuroprotective and antiapoptotic actions of deprenyl have previously been observed in vitro. Here we describe an antineurotoxic action of ...
Löser C - - 2000
Polyamines are highly regulated polycations which are essentially involved in cell growth and differentiation. Polyamines in food significantly contribute to the polyamine body pool. Dietary polyamines exert various direct and indirect trophic effects on the rat's immature intestine and play an important role during intestinal maturation. Human milk and that ...
Hayashi S - - 2000
The role of eIF4G during the initiation of protein synthesis was studied using mouse mammary carcinoma FM3A cells and FM4G cells that overproduce an N-terminally truncated form of eIF4G, which lacks the binding site of poly(A)-binding protein. An increase in eIF4G was correlated with an increase in protein synthesis and ...
Baker M W - - 2000
Receptor protein tyrosine phosphatases (RPTPs) are important for growth-cone migration [1-5], but their specific roles have yet to be defined. Previously, we showed that the growth cones of the Comb cell, an embryonic cell in the leech, express high levels of an RPTP called HmLAR2 [6,7]. Here, we report the ...
Byrne T J - - 2000
Previously we demonstrated that protein coded by the BRCA1 gene was expressed in normal human buccal cells. The present study confirmed that BRCA2 protein was similarly expressed in these cells. Messenger RNA for BRCA2 was detected with sequential use of two primer sets. Pooled cell samples from healthy donors reacted ...
Kondoh H - - 2000
BACKGROUND: In normal somatic cell cycle, growth and cell cycle are properly coupled. Although CDK (cyclin-dependent kinase) activity is known to be essential for cell cycle control, the mechanism to ensure the coupling has been little understood. RESULTS: We here show that fission yeast Mis3, a novel evolutionarily highly conserved ...
Furumitsu Y - - 2000
OBJECTIVE: To investigate polyamine metabolism in rheumatoid synovial adherent cells stimulated by interleukin- 1beta (IL-1beta). METHODS: Synovial adherent cells obtained from patients with rheumatoid arthritis (RA) were cultured and incubated in the presence or absence of human recombinant IL-1beta at a concentration of 10 ng/ml for 24 h. The cellular ...
Pereira M C - - 2000
Ultrastructural in situ hybridization was used to visualize the spatial distribution of poly (A)+ RNA and quantitate its relative amount within different cellular compartments of cardiomyocytes after T. cruzi infection. The amount of poly (A)+ RNA remained about the same up to 24 h post-infection. In contrast, its content was ...
de Vries T J - - 2000
Melanoma cell detection in peripheral blood by tyrosinase reverse transcription-polymerase chain reaction (RT-PCR) is usually performed on RNA isolated from whole blood using a guanidinium isothiocyanate (GITC)/phenol extraction method or from Ficoll Hypaque isolated mononuclear cells. The first method contains environmentally harmful reagents, and the second is laborious in the ...
Smart L B - - 2000
Guard cells are specialized and metabolically active cells which arise during the differentiation of the epidermis. Using Nicotiana glauca epidermal peels as a source of purified guard cells, we have constructed a cDNA library from guard cell RNA. In order to isolate genes that are predominantly expressed in guard cells, ...
Hoet P H - - 2000
The natural polyamines putrescine, cadaverine, spermidine, and spermine are found in all cells. These (poly)cations exert interactions with anions, e.g., DNA and RNA. This feature represents their best-known direct physiological role in cellular functions: cell growth, division, and differentiation. The lung and, more specifically, alveolar epithelial cells appear to be ...
Schipper R G - - 2000
The natural polyamines (putrescine, spermidine and spermine) are ubiquitous low-molecular aliphatic amines that play multifunctional roles in cell growth and differentiation. Recently, evidence has merging that polyamines are actively involved in cell death. Changes in polyamine homeostasis have been reported during cell death of nerve cells, in programmed cell death ...
Blantz R C - - 2000
Arginine and its metabolites exert physiological effects on the vasculature and on the kidney and also provide important influences on the regulation of cell proliferation. We summarize the known information regarding two major metabolites of arginine: (a) nitric oxide (NO) and (b) agmatine, decarboxylated arginine. Both agents appear to interact ...
Honda M - - 2000
BACKGROUND & AIMS: Translation of the hepatitis C virus (HCV) polyprotein is mediated by an internal ribosome entry site (IRES) that is located within the 5' nontranslated segment of the viral RNA. This RNA segment is known to form binary complexes with isolated 40S ribosome subunits in vitro, but there ...
Seiler N - - 2000
Spermine is a constituent of all vertebrate cells. Nevertheless, it exerts toxic effects if it accumulates in cells. Spermine is a natural substrate of the FAD-dependent polyamine oxidase, a constitutive enzyme of many cell types. It has been reported that the toxicity of spermine was enhanced if polyamine oxidase was ...
Ando A - - 2000
Gyrate atrophy of the choroid and retina is a chorioretinal degeneration caused by hyperornithinemia and a deficiency of ornithine-delta-aminotransferase (OAT). We recently showed that ornithine exhibits cytotoxicity to human retinal pigment epithelial (RPE) cell lines treated with the OAT inhibitor, 5-fluoromethylornithine (5-FMOrn), and suggested that this system may be an ...
Summerton J - - 1999
RNase H-competent phosphorothioates (S-DNAs) have dominated the antisense field in large part because they offer reasonable resistance to nucleases, they afford good efficacy in cell-free test systems, they can be targeted against sites throughout the RNA transcript of a gene, and they are widely available from commercial sources at modest ...
Supattapone S - - 1999
We report that branched polyamines, including polyamidoamide dendimers, polypropyleneimine, and polyethyleneimine, are able to purge PrP(Sc), the protease-resistant isoform of the prion protein, from scrapie-infected neuroblastoma (ScN2a) cells in culture. The removal of PrP(Sc) by these compounds depends on both the concentration of branched polymer and the duration of exposure. ...
Khromykh A A - - 1999
Successful trans-complementation of the defective Kunjin virus (KUN) RNA FLdGDD with a deletion of the RNA polymerase motif GDD in the NS5 gene by using a BHK cell line, repBHK, that continuously produced a functionally active KUN replication complex (RC) from replicon RNA was recently reported (A. A. Khromykh, M. ...
Chiappa S A - - 1999
OBJECTIVE: Primitive neuroectodermal tumors (PNETs) are thought to be derived from early central nervous system precursors. Therefore, we hypothesized that the neurotrophins (nerve growth factor, brain-derived neurotrophic factor, and neurotrophin-3) and their receptors (TrkA, TrkB, and TrkC), which are involved in the proliferation, differentiation, and survival of neuronal cells, might ...
Bauer M - - 1999
The identification of menstrual blood stains can be improved by detection of messenger ribonucleic acid (mRNA) specific for epithelial (endometrial) cells. RNA molecules, however, are believed to be unstable and require careful sample processing. In this study, we have investigated the extraction of RNA suitable for reverse transcriptase-polymerase chain reaction ...
Ohnishi T - - 1999
Techniques for isolating the desired cell populations from complex tissues are essential for characterizing cells through mRNA analysis. We established a procedure for isolating pure mucosal epithelium from the human alimentary tract. To do this, we made rotating hooks that hold mucosal strips and detach the epithelial sheets from the ...
Schipper R G - - 1999
Ornithine decarboxylase (ODC), a regulatory enzyme of polyamine biosynthesis, is involved in cell growth and differentiation. Lack of information about the exact cellular and subcellular localization of ODC is one of the main obstacles to precise interpretation of the biological roles of the ODC/polyamine system. Here we describe the development ...
Pohl U - - 1999
To investigate the role of the deleted in colorectal carcinoma gene (DCC) in cells of pancreatic origin (MiaPaCa-2) we established cell lines stably expressing DCC antisense RNA. Expression of DCC antisense RNA led to striking alterations in the MiaPaCa-2 cell line. Antisense transfectants had nearly lost adherence and had acquired ...
Debiaggi M - - 1999
Objective: To examine the amount of cell-free and cell-associated virus in cervicovaginal secretions (CVS) of HIV-infected women. Methods: Paired cervicovaginal and blood samples from 61 seropositive women were quantitatively evaluated by competitive polymerase chain reaction (cPCR) and reverse transcription-PCR (cRT-PCR) for: (1) genomic RNA from plasma and cell-free CVS, and ...
Alm K - - 1999
The polyamines-putrescine, spermidine, and spermine-are essential for normal cell proliferation. Polyamine depletion affects DNA structure and synthesis. Topoisomerase II (topo II) is also necessary for normal cell proliferation, and it has been shown in vitro that polyamines may affect topo II activity. In order to investigate the effect of polyamine ...
Dai H - - 1999
Polyamine oxidase functions in the polyamine catabolic pathway, converting N1-acetyl-spermidine and -spermine into putrescine (Put) and spermidine (Spd), respectively, thereby facilitating homeostasis of intracellular polyamine pools. Inhibition of polyamine oxidase in hematopoietic cells by a specific inhibitor, N,N'-bis(2,3-butadienyl)-1,4-butanediamine (MDL-72,527), reduces the levels of Put and Spd and induces the accumulation ...
Cullis P M - - 1999
BACKGROUND: Many mammalian cells possess an active polyamine uptake system but little is known about the molecular mechanism of this transporter. The fate of polyamines taken up from the medium and the relationship to polyamine homeostasis remains to be fully established. The aim of this study was to develop a ...
Takahashi K - - 1999
OBJECTIVE: The role of structural and host defensive cells in periapical lesions has been assessed previously by morphometric and immunohistochemical studies. The aim of this study was to investigate the function of peri- apical cells by employing molecular techniques to estimate the cell synthetic activity, proliferation and apoptosis in these ...
Diez C - - 1999
Gene expression is one key mechanism to regulate cell growth and differentiation. It is usually determined by Northern blotting or RT-PCR. However, studies with primary cell cultures are frequently hampered due to contaminating cells such as fibroblasts. We have developed a method to isolate intact full-size mRNA from sorted cells. ...
Merali S - - 1999
DL-alpha-Difluoromethylornithine (DFMO) causes polyamines of the AIDS-associated opportunistic pathogen Pneumocystis carinii to diminish 15 times more rapidly than mammalian host cells. The proposed mechanism was that, unlike mammalian cells, P. carinii is unable to regulate polyamine catabolism when synthesis is blocked. To test this, the responses of the polyamine catabolic ...
Champney W S - - 1999
Three pairs of related macrolide antibiotics, differing at the 11,12 position of the macrolactone ring, were compared for effects on growth rate, cell viability, protein synthesis, and 50S ribosomal subunit formation in Staphylococcus aureus cells. For each parameter measured, the 11,12 carbonate-derivatized compound was more inhibitory compared with the corresponding ...
Satoh N - - 1999
Polyamines are considered to be important intracellular molecules for the proliferation of cancer cells. In this study, effects of methyl-glyoxal bis(cyclopentylamidinohydrazone) (MGBCP), a potent inhibitor of the polyamine biosynthetic pathway, on the growth of human osteosarcoma HuO9 cells have been investigated. MGBCP dose-dependently inhibited the growth of HuO9 cells, in ...
Dirks R W - - 1999
Mitosis is characterized by condensation of chromatin, cessation of RNA transcription, and redistribution of nuclear proteins. We investigated the distribution of the hypo- and hyperphosphorylated forms of RNA polymerase II in mitotic cells from different cell lines by immunofluorescence. In interphase cells, the hyperphosphorylated RNA polymerase II (Pol IIO) is ...
Ghosh S - - 1999
mRNA decay in prokaryotic cells involves the action of both endo- and exoribonucleases. In Escherichia coli, degradation of RNA to the mononucleotide level was thought to depend on RNase II and polynucleotide phosphorylase. Here, we show that the enzyme oligoribonuclease is an essential part of this process as well. Thus, ...
Ray R M - - 1999
The polyamines spermidine and spermine and their precursor putrescine are intimately involved in and are required for cell growth and proliferation. This study examines the mechanism by which polyamines modulate cell growth, cell cycle progression, and signal transduction cascades. IEC-6 cells were grown in the presence or absence of DL-alpha-difluoromethylornithine ...
Hansson S R - - 1999
A growing body of evidence suggests that serotonin plays an important role in the early development of both neural and non-neural tissues from vertebrate and invertebrate species. Serotonin is removed from the extracellular space by the cocaine- and antidepressant-sensitive serotonin transporter, thereby limiting its action on receptors. In situ hybridization ...
Patel A R - - 1999
Activator protein 1 (AP-1) is a group of dimeric transcription factors composed of protooncogene (Jun and Fos) subunits that bind to a common DNA site, the AP-1 binding site. The proteins of c-Jun, JunB, and Fos are essential for initiation of the cell cycle. Conversely, the activation of the junD ...
Ohsaki Y - - 1999
The tumoral production of brain natriuretic peptide (BNP) was studied using 9 small cell lung cancer (SCLC) cell lines which were established from patients with small cell lung cancer. BNP cDNA fragment was generated from 20 microg total RNA which was prepared from the human right cardiac atrium by reverse ...
Wataya Y - - 1999
The molecular mechanism of cell death induced by 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine (ECyd: Figure 1), a potent inhibitor of RNA synthesis, was performed using mouse mammary tumor FM3A cells and human fibrosarcoma HT1080 cells. ECyd induced the characteristics of apoptosis on these cells, such as morphological changes, DNA fragmentations (Figure 2), and caspase-3-like ...
Pignata S - - 1999
Intestinal cells are able both to synthesize and take up putrescine, the main compound of the metabolic polyamine pathway. Polyamine binding to nuclear macromolecules is thougth to modulate DNA synthesis and transcription. Our aim was to study the fate of putrescine when taken up from the medium in the enterocyte-like ...
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