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Results 551 - 600 of 1810
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Chen Allan Y - - 2005
The silatecan 7-tert-butyldimethylsilyl-10-hydroxy-camptothecin (DB-67) represents a new generation of camptothecin derivatives that exhibits a potent in vitro DNA topoisomerase I (TOP1)-mediated DNA-damaging activity, improved blood stability, and holds significant promise for the treatment of human cancers. In this study, we characterize the role of TOP1 in mediating the radiosensitization activity ...
Khafif Avi - - 2005
PURPOSE: Curcumin, a potential chemopreventive agent, was found to inhibit cancer cells in S/G2M phases of the cell cycle, when radiation is more effective. The purpose of the current study was to investigate whether curcumin can sensitize squamous cell carcinoma (SCC) cells to the ionizing effects of irradiation. METHODS: Curcumin ...
Wang Hongyan - - 2005
CHK1 is one of the most important checkpoint proteins in mammalian cells for responding to DNA damage. Cells defective in CHK1 are sensitive to ionizing radiation (IR). The mechanism by which CHK1 protects cells from IR-induced killing remains unclear. DNA double strand breaks (DSBs) induced by IR are critical lesions ...
Baatout Sarah - - 2005
Ionizing radiation is widely used in radiotherapy, in order to promote an apoptotic response in cancerous cells. Since the need to find new substances that would enhance the radiation-induced apoptosis in cancerous cells is great, we studied the effect of epigallocatechin-gallate (EGCG, a tea component), resveratrol (a wine component) and ...
Bryan R A - - 2005
The polysaccharide capsule of the pathogenic fungus Cryptococcus neoformans is an important virulence factor, but relatively little is known about its architecture. We applied a combination of radiological, chemical, and serological methods to investigate the structure of this polysaccharide capsule. Exposure of C. neoformans cells to gamma radiation, dimethyl sulfoxide, ...
Sato Shinsuke - - 2005
The role of HER-2/neu in the response of esophageal cancer to radiation is not well known. The purpose of this study was to evaluate the effect of an anti-HER-2/neu antibody trastuzumab on the proliferation, cell cycle distribution, and radiosensitivity of esophageal cancer cell lines. Expression of HER-2/neu protein by four ...
Munshi Anupama - - 2005
The clonogenic cell survival assay determines the ability of a cell to proliferate indefinitely, thereby retaining its reproductive ability to form a large colony or a clone. This cell is then said to be clonogenic. A cell survival curve is therefore defined as a relationship between the dose of the ...
Zhou Tong - - 2005
In an attempt to determine the possible role of Ku-dependent end joining in mutagenesis resulting from DNA double-strand breaks, mutations induced by bleomycin at the hprt locus in plateau phase normal CHO-K1 and Ku-deficient xrs-6 cells were examined. Plateau phase xrs-6 cells were 500-fold more sensitive to chronic bleomycin treatment ...
Gudowska-Nowak E - - 2005
The aim was to investigate further the relationship between radiation-induced mitotic delay and the expression of chromosome damage in V79 cells. Recently published data on the time-course of chromosome aberrations in V79 first-cycle metaphases after exposure to 10.4 MeV u(-1) Ar ions (LET = 1226 keV microm(-1)) were supplemented and ...
Karim Aftab - - 2005
BACKGROUND: Glioblastoma multiforme (GBM) is a high-grade primary brain tumor that is refractory to current forms of treatment. In cell studies, the growth rate of GBM cells correlates with the level of Cyclooxygenase-2 (COX-2) enzyme expression. COX-2 has been implicated in carcinogenesis of systemic cancers. Recently, COX-2 inhibition has been ...
Obata Atsushi - - 2005
64Cu-diacetyl-bis(N4-methylthiosemicarbazone) (64Cu-ATSM) is a promising radiotherapy agent for the treatment of hypoxic tumors. In an attempt to elucidate the radiobiological basis of 64Cu-ATSM radiotherapy, we have investigated the cellular response patterns in vitro cell line models. Cells were incubated with 64Cu-ATSM, and the dose-response curves were obtained by performing a ...
Raaphorst G P - - 2005
The responses of cells with mutated DNA repair pathways were compared for cisplatin, radiation and combination treatments. The knockout of the nonhomologous endjoining (NHEJ) pathway resulted in increased radiation sensitivity, but no change in cisplatin response in the mouse cells and increased radiosensitivity but decreased cisplatin sensitivity in chicken cells. ...
Pfeiffer Petra - - 2005
Double-strand breaks (DSBs) in genomic DNA are induced by ionizing radiation or radiomimetic drugs, but they also occur spontaneously during the cell cycle at quite significant frequencies. In vertebrate cells, nonhomologous DNA end joining (NHEJ) is considered the major pathway of DSB repair. NHEJ is able to rejoin two broken ...
Dowling Kevin - - 2005
PURPOSE: To determine whether delayed and bystander effects can be seen in both a non malignant teleost fish cell line, (CHSE) and a malignant teleost fish cell line (EPC) when exposed to low doses of ionising radiation and genotoxic pollutants. METHODS: Teleost fish cells were briefly exposed to radiation and ...
Azria David - - 2005
INTRODUCTION: Radiotherapy (RT) is considered a standard treatment option after surgery for breast cancer. Letrozole, an aromatase inhibitor, is being evaluated in the adjuvant setting. We determined the effects of the combination of RT and letrozole in the aromatase-expressing breast tumour cell line MCF-7CA, stably transfected with the CYP19 gene. ...
Bonner William M - - 2004
For several decades, the prevailing paradigm for modeling the effects of ionizing radiation (IR) on living systems was the target model with its inherent assumptions--that only those cells in the radiation path whose molecules sustained collisions with high energy particles and rays were damaged, that the damage was proportional to ...
Scott B R - - 2004
This paper links genomic instability, bystander effects, and adaptive response in mammalian cell communities via a novel biological-based, dose-response model called NEOTRANS3. The model is an extension of the NEOTRANS2 model that addressed stochastic effects (genomic instability, mutations, and neoplastic transformation) associated with brief exposure to low radiation doses. With ...
Coates Philip J - - 2004
The major adverse consequences of radiation exposures are attributed to DNA damage in irradiated cells that has not been correctly restored by metabolic repair processes. However, the dogma that genetic alterations are restricted to directly irradiated cells has been challenged by observations in which effects of ionizing radiation arise in ...
Tang W Y - - 2004
Development of radiation resistance is one of the major reasons that cancer cells do not respond to radiotherapy and the mechanism for resistance is still not clear. Two sublines of human hepatocellular carcinoma Hep G2 cells were established from cells that survived two different irradiation regimes, 2 Gy for 10 ...
Chavaudra Nicole - - 2004
BACKGROUND AND PURPOSE: There is still confusion in the choice of the molecular assays to predict the radiation response of human cells. The case of tumours appears to be particularly complex, may be because of their instability and heterogeneity. The aim of this study was to investigate quantitatively the relationships ...
Suzuki Masao - - 2004
Radiation-induced damage to living cells results from either a direct hit to cellular DNA, or from indirect action which leads to DNA damage from radiation produced radicals. However, in recent years there is evidence that biological effects such as cell killing, mutation induction, chromosomal damage and modification of gene expression ...
Jeffrey S. Murley
Murley, J. S., Kataoka, Y., Cao, D., Li, J. J., Oberley, L. W. and Grdina, D. J. Delayed Radioprotection by NFκB-Mediated Induction of Sod2 (MnSOD) in SA-NH Tumor Cells after Exposure to Clinically Used Thiol-Containing Drugs. Radiat. Res. 162, 536–546 (2004). The ability of thiol-containing reducing agents to activate transcription ...
Loucas Bradford D - - 2004
To examine more fully the nature of chromosomal radiosensitivity in ataxia telangiectasia (AT) cells, we employed 24-color combinatorial painting to visualize 137Cs gamma-ray-induced chromosome-type aberrations in cells of two AT and one normal primary human fibroblast strains irradiated in log-phase growth. As a measure of misrejoined radiation-induced DSBs, we quantified ...
Feinendegen L E - - 2004
PURPOSE: To analyse the lethality to mammalian cells of (125)I-decays in DNA, in antipyrine in the whole cell and in oligodeoxynucleotides in the nucleus outside DNA as a function of Auger event-site and number. MATERIALS AND METHODS: Auger events cause both low- and high-linear energy transfer energy depositions including charge ...
Kriehuber R - - 2004
OBJECTIVE: To study the biological effectiveness of Auger electrons emitted by (99m)Tc on cell survival, induction of apoptosis and micronucleus (MN) formation in the human squamous cell carcinoma cell line SCL-II and compare the effects observed to those observed after exposure to external 60Co gamma radiation. MATERIAL AND METHODS: Cells ...
Przybyszewski Waldemar M - - 2004
The multicellular megacolonies of human melanoma Me45 line growing on one part of the bottom of culture flasks were irradiated with 5 Gy (60Co), whereas megacolonies growing on the second part of the bottom were shielded. The bystander effect of radiation-traversed cells on non-traversed cells was studied during postradiation co-cultivation. ...
Kim Hyo-Soo - - 2004
The biologic mechanisms for the success and failure of intravascular radiation therapy after angioplasty have not been well studied. We investigated the molecular mechanism of radiation-induced cell cycle arrest in vascular smooth muscle cell (VSMC) and examined whether p21 knock-out is a cause of radiation failure. Using different dosages of ...
Wang Hongyan - - 2004
ATR is one of the most important checkpoint proteins in mammalian cells responding to DNA damage. Cells defective in normal ATR activity are sensitive to ionizing radiation (IR). The mechanism by which ATR protects the cells from IR-induced killing remains unclear. DNA double-strand breaks (DSBs) induced by IR are critical ...
Enns Louise - - 2004
Exposure to environmental radiation and the application of new clinical modalities, such as radioimmunotherapy, have heightened the need to understand cellular responses to low dose and low-dose rate ionizing radiation. Many tumor cell lines have been observed to exhibit a hypersensitivity to radiation doses <50 cGy, which manifests as a ...
Nishikawa Takashi - - 2004
The melanoma differentiation-associated gene-7 (mda-7) was identified by virtue of its enhanced expression in human melanoma cells induced into terminal differentiation. Enforced expression of mda-7 in human cancer cell lines of diverse origins results in the suppression of growth and induction of apoptosis. We have shown that adenoviral-mediated mda-7 (Ad-mda7) ...
Yoshio Hosoi
Hosoi, Y., Matsumoto, Y., Enomoto, A., Morita, A., Green, J., Nakagawa, K., Naruse, K. and Suzuki, N. Suramin Sensitizes Cells to Ionizing Radiation by Inactivating DNA-Dependent Protein Kinase. Radiat. Res. 162, 308–314 (2004). Here we report that suramin sensitizes LM217, MDA-MB-468, T98G and A431 cells to ionizing radiation. Suramin sensitized ...
Michel Rosana B - - 2004
PURPOSE: The ability of antibodies (Abs) conjugated to radionuclides emitting low-energy electrons to specifically kill nonadherent lymphoma target cells in vitro was demonstrated previously. This study extends this work to adherent carcinoma cells. The fact that these cells are spread out on plastic can potentially make it more difficult to ...
Hosoi Yoshio - - 2004
Here we report that suramin sensitizes LM217, MDA-MB-468, T98G and A431 cells to ionizing radiation. Suramin sensitized cells to X radiation in a dose-dependent fashion, and longer exposure to suramin before X irradiation resulted in more efficient sensitization. The dose-modifying factors calculated from the survival curves were 1.18 in LM217 ...
Marples B - - 2004
Low-dose hyper-radiosensitivity describes a phenomenon by which cells die from excessive sensitivity to small single doses of ionizing radiation below approximately 20-30 cGy. This review describes experimental data that strongly imply that low-dose hyper-radiosensitivity is exclusively associated with the survival response of cells in the G2 phase of the cycle. ...
Jeong Min Ho - - 2004
Ionizing radiation is one of the most effective tools in cancer therapy. In a previous study, we reported that protein tyrosine kinase (PTK) inhibitors modulate the radiation responses in the human chronic myelogenous leukemia (CML) cell line K562. The receptor tyrosine kinase inhibitor, genistein, delayed radiation-induced cell death, while non-recepter ...
Albino A P AP Vector Research Ltd., New York, New York 10019, USA. - - 2004
DNA double strand breaks (DSBs) are potentially carcinogenic lesions. The induction of DSBs triggers phosphorylation of histone H2AX. Phosphorylated H2AX, denoted p-H2AX, may be detected immunocytochemically and the intensity of p-H2AX immunofluorescence (IF) reveals the frequency of DSBs. Using this assay we tested whether the exposure of A549 human pulmonary ...
Pawlik Timothy M - - 2004
Multiple pathways are involved in maintaining the genetic integrity of a cell after its exposure to ionizing radiation. Although repair mechanisms such as homologous recombination and nonhomologous end-joining are important mammalian responses to double-strand DNA damage, cell cycle regulation is perhaps the most important determinant of ionizing radiation sensitivity. A ...
Lee Jin Hyup - - 2004
Exposure of cells to ionizing radiation leads to formation of reactive oxygen species, which are associated with radiation-induced cytotoxicity. Therefore, compounds that scavenge reactive oxygen species may confer radioprotective effects. Superoxide dismutase (SOD) mimetics have been shown to be protective against cell injury caused by reactive oxygen species. The objective ...
Abraham S K - - 2004
The main aim of this work was to test the hypothesis that instant coffee, a commonly consumed polyphenolic beverage with antioxidant activity, can protect mammalian cells against genotoxic effects in vitro. For this purpose, the L5178Y mouse lymphoma cell line was selected to assess modulatory effects of coffee on the ...
Baatout Sarah - - 2004
Over the past 15 years, some potential anticarcinogenic and anti-inflammatory effects of antioxidants have been defined. Antioxidants are known to act as powerful free-radical scavengers. Free radicals are able to induce DNA strand breaks and oxidative modifications of DNA bases and are not only produced naturally in the cell following ...
Mehrotra Ravi - - 2004
Carcinoma of the oral cavity constitutes approximately 40% of overall malignant tumours in India, with an incidence of about 56,000 cases per year. Radiation responses in oral cancer cells by cytology have not been extensively studied. 102 patients with squamous cell carcinoma of the oral cavity treated by fractionated radiotherapy ...
Mitchel R E J - - 2004
The bystander effect refers to the biological response of a cell resulting from an event in an adjacent or nearby cell. Such effects depend on intercellular communication and amplify the consequences of the original event. These responses are of particular interest in the assessment of ionizing radiation risk because at ...
Akudugu John M - - 2004
Some photon resistant tumours are sensitive to neutrons but no predictive methods exist which could identify such tumours. In a recent study addressing this clinically important issue, we demonstrated that relative biologic effectiveness (RBE) values for p(66)/Be neutrons estimated from micronucleus (MN) data correlate positively with RBE values obtained from ...
Robichová Sona - - 2004
INTRODUCTION: N-Nitrosomorpholine (NMOR), present in the workplace of tyre chemical factories, is a known hepatocarcinogen. This compound belongs to the group of N-nitrosamines, which are indirect-acting and require metabolic activation. However, the mechanism of its carcinogenic effect is not completely clear. AIMS: The objective of this study was (i) to ...
ATM switches respond to UBR congestion by dropping cells when their buffers becomefull.
Huang Lei - - 2004
Exposure to ionizing radiation can result in delayed effects that can be detected in the progeny of an irradiated cell multiple generations after the initial exposure. These effects are described under the rubric of radiation-induced genomic instability and encompass multiple genotoxic endpoints. We have developed a green fluorescence protein (GFP)-based ...
Chen Miao-Fen - - 2004
Caffeic acid phenethyl ester (CAPE) is a biologically active ingredient of honeybee propoplis. The cytotoxicity and radiation sensitization effects of CAPE were evaluated in human lung cancer A549 cells and normal lung fibroblast WI-38 cells. A549 cells treated with 6 microg/ml CAPE showed marked growth inhibition (60%) at 48 hr ...
Tucker James D - - 2004
Space exploration has the potential to yield exciting and significant discoveries, but it also brings with it many risks for flight crews. Among the less well studied of these are health effects from space radiation, which includes the highly charged, energetic particles of elements with high atomic numbers that constitute ...
Zhang Yin - - 2004
Histone deacetylase (HDAC) inhibitors are emerging therapeutic agents with potential for disruption of critical cellular processes in cancer cells. Transcriptional regulation, differentiation, cell cycle arrest, radiation sensitization, and apoptosis have been observed in response to exposure to HDAC inhibitors. In the present study, we observed that several potent HDAC inhibitors, ...
Baatout Sarah - - 2004
A search for new agents that can sensitise cancer cells to ionising radiation is of continual interest and mainly due to the use of radiation in cancer therapy. Resveratrol, a powerful antioxidant has been shown to inhibit carcinogenesis in animal models. The purpose of this study was to examine whether ...
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