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Results 351 - 400 of 1491
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Van Vu Quang - - 2008
Peripheral CD103(+)Foxp3(+) regulatory T cells (Tregs) can develop both from conventional naive T cells upon cognate Ag delivery under tolerogenic conditions and from thymic-derived, expanded/differentiated natural Tregs. We here show that CD47 expression, a marker of self on hematopoietic cells, selectively regulated CD103(+)Foxp3(+) Treg homeostasis at the steady state. First, ...
Acosta Juan C JC Cell Proliferation Group, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College, London, United - - 2008
Senescence is an irreversible growth arrest with important physiological implications as it contributes to tumour suppression and may have a role in aging. During senescence, cells suffer profound phenotypic changes affecting amongst others cell morphology and chromatin structure. Senescent cells also undergo significant transcriptional changes, such as the increased production ...
Bigl Katrin - - 2008
Advanced glycation endproducts (AGEs) arise from the reaction of sugars with side chains and the N-terminus of proteins and are thought to be involved in the pathogenesis of several diseases by inducing oxidative stress, inflammation and cell death presumably mediated through activation of the receptor of AGE (RAGE). To address ...
Stefanidis Konstantinos - - 2008
OBJECTIVE: The aim of this study was to assess the impact of nevirapine on a cervix carcinoma cell line. METHODS: HeLa cells were cultured in Dulbecco's modified Eagle medium supplemented with 20% fetal bovine serum at 37 degrees C and humidified 10% CO(2) in air. Nevirapine was purified from commercially ...
Kim Reuben H RH University of California, Los Angeles School of Dentistry, Center for the Health Sciences, Los Angeles, CA 90095, - - 2008
Enhanced expression of human telomerase reverse transcriptase (hTERT) occurs frequently during cellular immortalization. The current study was undertaken to determine the mechanism regulating the hTERT promoter activity during cellular immortalization of human oral keratinocytes. Normal human oral keratinocytes (NHOKs) were immortalized with Bmi-1 and the E6 oncoprotein of human papillomavirus ...
Li Yue - - 2008
Age-related macular degeneration (AMD) remains high incidence and accounts for a main cause of blindness in ageing people, but its mechanism is still poorly understood. Ageing and associated dysfunction of retinal pigment epithelial (RPE) cells were believed to be the pathological onset of AMD. 20S proteasome has been tightly correlated ...
Ohshima Susumu - - 2008
Aberrant nuclear morphology, such as nuclei with irregular shapes or fragmented nuclei, is often observed in senescent cells, but its biological significance is not fully understood. My previous study showed that aberrant nuclear morphology in senescent human fibroblasts is attributable to abnormal mitosis in later passages. In this study, the ...
Chang Maria - - 2008
In mammals, the rate of somatic growth is rapid in early postnatal life but then slows with age, approaching zero as the animal approaches adult body size. To investigate the underlying changes in cell-cycle kinetics, [methyl-H]thymidine and 5'-bromo-2'deoxyuridine were used to double-label proliferating cells in 1-, 2-, and 3-wk-old mice ...
Fischer Jared M - - 2008
To determine the relationship between aging, cell proliferation and mutation in different cell types, hearts, brains and kidneys from G11 PLAP mice between 1 week and 24 months of age were examined. Mutant cells were detected in tissue sections by staining for Placental Alkaline Phosphatase (PLAP) activity, an activity that ...
Wieser Matthias - - 2008
Telomere-dependent replicative senescence is one of the mechanisms that limit the number of population doublings of normal human cells. By overexpression of telomerase, cells of various origins have been successfully immortalized without changing the phenotype. While a limited number of telomerase-immortalized cells of epithelial origin are available, none of renal ...
Wrande Marie - - 2008
Several bacterial systems show behavior interpreted as evidence for stress-induced mutagenesis (adaptive mutation), a postulated process by which nongrowing cells temporarily increase their general mutation rate. Theoretical considerations suggest that periodic stress-induced general mutagenesis would not be advantageous in the long term, due to the high cost of deleterious mutations. ...
Niu Haitao - - 2008
It is puzzling how autoreactive B cells that escape self-tolerance mechanisms manage to produce Abs that target vital cellular processes without succumbing themselves to the potentially deleterious effects of these proteins. We report that censorship indeed exists at this level: when the Ab synthesis in the cell is up-regulated in ...
Gruber Helen E - - 2008
The aging human intervertebral disc contains a sizeable population of senescent cells. Since senescent cells cannot divide, senescence reduces the disc's ability to generate new cells to replace existing ones lost to necrosis or apoptosis. The objectives of the present work were: (1) to develop a reliable in vitro model ...
Kurabayashi Rie - - 2008
Critically shortened, dysfunctional telomeres may play a role in the genetic instabilities commonly found in cancer. We analyzed 30 surgical specimens of invasive breast carcinoma from women aged 34 to 91 years and estimated telomere lengths as telomere-to-centromere ratio values in the 5 different cell types comprising breast tissue in ...
Funk-Keenan Jhondra - - 2008
Endopolyploidy is the generation of polyploid cells by DNA replication without subsequent cell division and is correlated with hypertrophic growth or growth via cell size. Thus, selection that alters growth may also change onset and frequency of endopolyploidy as a correlated response. We search for endopolyploidy in the liver in ...
Shervington Amal - - 2009
Telomerase expression strongly correlates with the grade of malignancy in glioma with inhibition illustrating a definite increase in chemosensitivity. This study was designed to investigate the effects of a green tea derivative, epigallocatechin-3-gallate (EGCG); together with either cisplatin or tamoxifen in glioma, and to investigate whether these effects are mediated ...
Ksiazek Krzysztof - - 2008
The accumulation of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) exemplifies oxidative DNA injury, which is strongly implicated in ageing. We show that human peritoneal mesothelial cells (HPMCs) from donors >75 years have lower proliferative capacity but increased 8-OH-dG content compared with cells from individuals <25 years. We detected a positive relationship between the donor's ...
Aida Junko - - 2008
We investigated the telomere lengths of individual cell types in lingual mucosa using an improved tissue quantitative fluorescence in situ hybridization (Q-FISH) method. Our tissue Q-FISH method compensates for partially cut nuclei in a tissue section by using the telomere:centromere ratio (TCR). We normalized our TCR measurements (NTCR) using a ...
Lin Jian - - 2008
Telomerase maintains telomere length and has been implicated in both aging and carcinogenesis of human cells. This enzyme is a specialized ribonucleoprotein (RNP) complex, minimally consisting of two essential components: the protein catalytic subunit TERT (telomerase reverse transcriptase) and the integral RNA moiety TR (telomerase RNA, TERC). Both TERT and ...
Stampfer, Martha R.
Telomerase is reactivated in almost all human breast cancers; loss of telomeric protection can lead to genomic instability. This proposal is to study telomerase reactivation and telomere protection in newly immortal, p53+ human mammary epithelial cells (HMEC), and to determine if these cells may be especially sensitive to therapies that ...
Rappl Gunter - - 2008
CD7(-) T cells constitute a distinct subset within the CD4(+) and CD8(+) T cell populations; their developmental and functional relationship to the majority of CD7(+) T cells, however, remained so far unresolved. We here elucidate that CD7(-) cells represent aging T cells in late memory cell development characterized by a ...
Vinoth Kumar Jayaseelan - - 2008
The use of human embryonic stem (hES) cells in genotoxicity screening can potentially overcome the deficiencies associated with using immortalized cell lines, primary explanted somatic cells, and live animal models. Hence this study sought to compare the responses of hES cells and primary explanted somatic cells (IMR-90 cells, human fetal ...
Strub Graham M - - 2008
Cells are constantly exposed to a wide variety of stimuli and must be able to mount appropriate physiological responses in order to maintain proper form and function. Cells from every organism have evolved highly conserved mechanisms to cope with environmental changes, including the widely studied heat shock response (HSR), which ...
Kirk Karen E - - 2008
Telomere mutants have been well studied with respect to telomerase and the role of telomere binding proteins, but they have not been used to explore how a downstream morphogenic event is related to the mutated telomeric DNA. We report that alterations at the telomeres can have profound consequences on organellar ...
Omori Atsuko - - 2008
Placental/umbilical cord blood (CB) contains nucleated cells and hematopoietic stem/progenitor cells (CD34(+) cells). However it is difficult to predict the number of nucleated/CD34(+) cells in each CB before cell processing. Despite many previous studies from institutes affiliated with CB banks in metropolitan areas, little information is available regarding the characteristics ...
Sliwinska Malgorzata A - - 2009
Induction of senescence has been proposed as a possible in vivo tumor response to anticancer treatment. Senescent cancer cells are often polyploid, however, their route to polyploidy is poorly recognized (endoreduplication versus aberrant mitoses). We showed that after treatment of HCT116 cells with a low dose of doxorubicin most of ...
Kim Sahn-Ho - - 2008
Telomeres are maintained by three DNA-binding proteins (telomeric repeat binding factor 1 [TRF1], TRF2, and protector of telomeres 1 [POT1]) and several associated factors. One factor, TRF1-interacting protein 2 (TIN2), binds TRF1 and TRF2 directly and POT1 indirectly. Along with two other proteins, TPP1 and hRap1, these form a soluble ...
Temime-Smaali Nassima - - 2008
Topoisomerase (Topo) IIIalpha associates with BLM helicase, which is proposed to be important in the alternative lengthening of telomeres (ALT) pathway that allows telomere recombination in the absence of telomerase. Here, we show that human Topo IIIalpha colocalizes with telomeric proteins at ALT-associated promyelocytic bodies from ALT cells. In these ...
Zhao Yan-min - - 2008
AIM: To examine the ability of rapamycin to suppress growth and regulate telomerase activity in the human T-cell leukemia cell line Jurkat. METHODS: Cell proliferation was assessed after exposure to rapamycin by 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide assay. Cell cycle progression and apoptosis were determined by flow cytometry. The proteins important for ...
Jin Jinghua - - 2008
The influence of dendroflorin, a potentially active compound extracted from Dendrobium nobile, on cell growth and cell cycles was assessed in a human embryo lung fibroblastic MRC-5 cell line. An MTT assay indicated that dendroflorin benefits cell proliferation. Additionally, we used flow cytometry to examine the cell cycles in senescent ...
Bhatia Bobby - - 2008
Normal human prostate (NHP) epithelial cells undergo senescence in vitro and in vivo but the potential role of senescent NHP cells in prostate tumorigenesis remain unclear. Here we show that senescent NHP cells enhance the in vivo tumorigenicity of low-tumorigenic LNCaP prostate cancer and low/non-tumorigenic subset of cells (called L ...
Walen Kirsten H - - 2008
Cell senescence from exhausted cell expansions to cells with short, dysfunctional telomeres is considered to be a non-replicative, irreversible state with possibility in tumor therapy. This leads to questions of senescence-stability which in genomic-probe, manipulated senescent flat cells resulted in reversions to mitotic cells. Additionally, rarer mitoses were present spontaneously ...
Lee Myung Eun - - 2008
The telomeric G-rich 3' overhang is important for the maintenance of chromosomal integrity by stabilizing T-loop structure in which the 3' overhang invades the double-stranded telomeric DNA. However, the 3' overhang length has not been examined in different human cell lines, and its regulatory mechanism has not been revealed. In ...
Stadler Guido - - 2008
Maintenance of telomere length has been reported to be an absolute requirement for unlimited growth of human tumour cells and in about 85% of cases, this is achieved by reactivation of telomerase, the enzyme that elongates telomeres. Only in rare cases, like in human medullary thyroid carcinomas (MTC), telomerase activity ...
Chen Xiaochun - - 2008
Tert-butyl hydroperoxide (t-BHP), an analog of hydroperoxide, induced characteristic changes of senescence in human diploid fibroblasts WI-38 cells. It was reported that ginsenoside Rg1, an active ingredient of ginseng, ameliorated learning deficits in aged rats. The present study was aimed to investigate whether ginsenoside Rg1 can delay the premature senescence ...
Jacobus J A - - 2008
The toxicity of polychlorinated biphenyls (PCBs) has been attributed widely to receptor-mediated effects, buttressed by the popularity of the Toxic Equivalency Factor. We propose that a crucial toxic mechanism of lower-chlorinated PCBs is their enzymatic biotransformation to electrophiles, including quinoid metabolites, that bind intracellular sulfhydryl groups, such as those found ...
Thomson Alison - - 2008
Human embryonic stem cells (hESCs) are thought to be susceptible to chromosomal rearrangements as a consequence of single cell dissociation. Compared in this study are two methods of dissociation that do not generate single cell suspensions (collagenase and EDTA) with an enzymatic procedure using trypsin combined with the calcium-specific chelator ...
Vandromme Marie - - 2008
Permanent silencing of E2F-dependent genes is a hallmark of the irreversible cell cycle exit that characterizes terminally differentiated and senescent cells. The determinant of this silencing during senescence has been proposed to be the binding of the retinoblastoma protein Rb and the consequent methylation of H3K9. During ex vivo skeletal ...
Liao Chien-Huang - - 2008
Purified recombinant fungal immunomodulatory protein from Ganoderma tsugae (reFIP-gts) has anti-telomerase effects in human lung adenocarcinoma A549 cells. However, how reFIP-gts affects cancer cell fates remains unclear. Here, we demonstrated that reFIP-gts-treated lung cancer cells are arrested at G1 phase by flow cytometry and possess morphological phenotype consistent with cellular ...
Berletch Joel B JB Department of Biology, University of Alabama Birmingham, Birmingham, Alabama 35294, - - 2008
The ends of human chromosomes are protected from the degradation associated with cell division by 15-20 kb long segments of hexameric repeats of 5'-TTAGGG-3' termed telomeres. In normal cells telomeres lose up to 300 bp of DNA per cell division that ultimately leads to senescence; however, most cancer cells bypass ...
Kang, Kyoung-Ah
Telomerase activation is detected in most cancerous cells; hence, telomerase is a highly selective target for cancer therapy, which plays an important role in the apoptotic process. We have previously reported that the ginseng saponin metabolite, Compound K (20-O-D-glucopyranosyl-20(S)-protopanaxadiol, IH901), inhibits cell proliferation by inducing apoptosis and cell cycle arrest ...
Glotin Anne-Lise - - 2008
The etiology of age-related macular degeneration (AMD), the leading cause of blindness in the developed world, remains poorly understood, but may be related to cumulative oxidative stress. The prime target of the disease is the retinal pigmented epithelium (RPE). To study the molecular mechanisms underlying RPE degeneration, we investigated whether ...
Suzuki Masatoshi - - 2008
Replicative senescence is a fundamental feature in normal human diploid cells and results from dysfunctional telomeres at the Hayflick cell division limit. Ionizing radiation (IR) prematurely induces the same phenotypes as replicative senescence prior to the Hayflick limit. This process is known as stress-induced premature senescence (SIPS). Since the cell ...
Cuenca Francisco - - 2008
A series of tri- and tetra-substituted naphthalene diimides have been designed and synthesized. Several compounds show exceptional affinity for telomeric G-quadruplex DNA in classical and competition FRET assays and SPR studies. They inhibit telomerase in the TRAP assay, and show potent senescence-based short-term anti-proliferative effects on MCF7 and A549 cancer ...
Marie-Egyptienne, Delphine
Telomeres are nucleoprotein structures that protect the ends of chromosomes from recombination and fusion. Telomeres are prefentially maintained by the enzyme telomerase. Telomerase is a reverse transcriptase, minimally composed of two core components, a catalytic subunit, TElomerase Reverse Transcriptase (TERT) and an RNA subunit, Telomerase RNA (TR) that carries the ...
Krunic, Damir
Telomeres are specialized DNA-protein structures at the ends of the linear chromosomes that form protective caps. They are composed of multi-fold double-stranded 5’-TTAGGG-3’ repeats and a 3’ single stranded overhang that loops back and invades the duplex region. The so called T-loop structure is stabilized by a number of associated ...
van Doorn Wouter G - - 2008
This review examines the hypotheses that developmental programmed cell death in leaves is mediated (i) by sugar starvation in the leaf cells or (ii) by sugar accumulation in these cells. Experimental evidence for both hypotheses is critically discussed and found to be lacking. For example, some papers show that sugars ...
Ponsot Elodie - - 2008
Telomere length is an important measure of cell and tissue regenerative capacities. The mean telomere length is classically used as global indicator of a tissue telomere length. In skeletal muscle, which is made of postmitotic myonuclei and satellite cells (muscle stem cells), minimum telomere length is also used to assess ...
Vigetti Davide - - 2008
Human aortic smooth muscle cells (AoSMCs) change their extracellular matrix composition during aging, with direct effects on cellular events and cell migration. For example, active matrix metalloproteinase-2 (MMP-2) is synthesized only by young AoSMCs, whereas aged cells produce only the inactive zymogen form. The pro-MMP-2 activation in young cells depends ...
Nakamura Asako J - - 2008
ABSTRACT: BACKGROUND: Cellular senescence is a state reached by normal mammalian cells after a finite number of cell divisions and is characterized by morphological and physiological changes including terminal cell-cycle arrest. The limits on cell division imposed by senescence may play an important role in both organismal aging and in ...
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