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Results 401 - 450 of 1822
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Sturgeon Christopher M - - 2007
Chemical inhibitors of the G2 checkpoint can sensitize p53-defective cancer cells to DNA damage and several are in preclinical or clinical development. These compounds are commonly thought to increase killing at the G2/M transition by forcing cells to divide with unrepaired DNA. We examined the effects of the ATM/ATR inhibitor ...
Popova L - - 2007
OBJECTIVES: To evaluate the possible genotoxic effect of radiation exposure for dental diagnostic purposes as measured by the formation of micronuclei. METHODS: The micronucleus test was applied to buccal epithelium cells, which are target cells for dental radiography. Specimens of exfoliated buccal cells were collected from patients subjected to panoramic ...
Wu Feng - - 2007
The purpose of the present work was to examine gene expression patterns in a rat keratinocyte line exposed to a (56)Fe ion beam. The cells were exposed to 1.01 geV/nucleon (56)Fe ions generated by the NASA Space Radiation Laboratory facility. Data from Affymetrix rat microarrays (RAT 230_2) were processed by ...
Krueger S A - - 2007
Little is known about the mode of cell killing associated with low-dose hyper-radiosensitivity, the radiation response that describes the enhanced sensitivity of cells to small doses of ionizing radiation. Using a technique that measures the activation of caspase 3, we have established a relationship between apoptosis detected 24 h after ...
Finch Stuart C - - 2007
Beginning in 1895, with the discovery of x-rays, alpha and beta radiation, uranium, radium, thorium, and polonium, the fascinating story of the beginning of knowledge concerning the existence of ionizing radiation unfolds. This brief history of radiation and leukemia is divided into two main parts: the first 50 years, which ...
Nayak Tapan K - - 2007
INTRODUCTION: Advance clinical cancer therapy studies of patients treated with somatostatin receptor (sstr)-targeted [DOTA(0)-Tyr(3)]octreotide (DOTATOC) labeled with low-linear-energy-transfer (LET) beta(-)-emitters have shown overall response rates in the range of 15-33%. In order to improve outcomes, we sought to compare the therapeutic effectiveness of sstr-targeted high-LET alpha-emitting (213)Bi to that of ...
Jin C - - 2007
BACKGROUND AND OBJECTIVE: The inability of radiotherapy to eradicate completely certain human tumours may be due to the presence of resistant hypoxic cells. Several studies have confirmed the radiosensitizing effect of paclitaxel, a microtubular inhibitor. The object of this study was to evaluate the physicochemical characteristics of paclitaxel-loaded nanoparticles, and ...
Yasui Linda S - - 2007
We have explored the use of Hoechst 33342 (H33342) to carry radioactivity to the cell nucleus. H33342 enters cells and targets DNA at adenine-thymine-rich regions of the minor groove. Considerable membrane blebbing and ruffling occur in CHO cells within minutes after its addition to the culture medium in micromolar quantities. ...
Beickelman, Amy C.
Hypoxia within a solid tumor is known to cause resistance to radiation therapy. It is the biggest problem that cancer patients face during radiation treatment. In this study, a potential hypoxic cell sensitizer, AB2, was synthesized and then investigated for its ability to sensitize hypoxic cells to radiotherapy. The study ...
Rao B S Satish - - 2007
To understand the role of proteins involved in DSB repair modulating SLD recovery, chicken B lymphoma (DT 40) cell lines either proficient or deficient in RAD52, XRCC2, XRCC3, RAD51C and RAD51D were subjected to fractionated irradiation and their survival curves charted. Survival curves of both WT DT40 and RAD52 (-/-) ...
Jones Pamala - - 2007
The primary mechanism of biological damage to macromolecules from ionizing radiation is an indirect interaction that begins with the radiolysis of water. Ionization of water molecules causes them to split by a process called radiolysis. The event is a cascade of chemical transformations that result in the formation of free ...
Rave-Fränk Margret - - 2007
BACKGROUND AND PURPOSE: To test the combined effects of oxaliplatin and radiation versus cisplatin and radiation using human cervical and lung cancer cell lines. MATERIAL AND METHODS: CaSki cervical cancer cells, and A549 lung cancer cells were cultured under standard conditions. Cells were treated with escalating doses of gamma-irradiation (0-6 ...
Hill Jeff W - - 2007
BACKGROUND: Mutations and polymorphisms of OGG1, the major mammalian 8-oxoguanine repair activity, are associated with increased risk for several cancers. Decreased 8-oxoguanine repair capacity due to variant forms of the OGG1 gene is a common feature of numerous cancer cell lines. One such cell line, human KG-1 leukemia cells, has ...
Hofmann Werner - - 2007
The objective of the present study was to identify advantages and limitations of the application of microdosimetric concepts for inhaled radon progeny activities in the lungs. The methods employed for this analysis were a recently developed Monte-Carlo microdosimetry code for the calculation of energy deposition in bronchial target cells and ...
Schilling Daniela - - 2007
BACKGROUND: Squamous cell carcinoma of the head and neck (SCCHN) often contain highly radioresistant hypoxic regions, nonetheless, radiotherapy is a common treatment modality for these tumours. Reoxygenation during fractionated radiotherapy is desired to render these hypoxic tumour regions more radiosensitive. Hypoxia additionally leads to up-regulation of PAI-1, a protein involved ...
Fike John R - - 2007
Considerable data are now available regarding the radiation responsiveness of neural precursor cells that exist in the neurogenic regions of the mammalian forebrain. These cells and their progeny are extremely sensitive to irradiation, undergoing apoptosis after clinically relevant doses that do not result in overt tissue injury. In addition, there ...
Mairs Robert J - - 2007
Indirect effects may contribute to the efficacy of radiotherapy by sterilizing malignant cells that are not directly irradiated. However, little is known of the influence of indirect effects in targeted radionuclide treatment. We compared gamma-radiation-induced bystander effects with those resulting from exposure to three radiohaloanalogues of meta-iodoben-zylguanidine (MIBG): [(131)I]MIBG (low ...
Cassidy Cheryl L - - 2007
Chinook salmon cells were exposed to gamma radiation and chromosome damage was assessed using the micronucleus assay. The salmon cells were resistant to radiation at all doses compared to human and mammalian cells. We used an indirect approach to determine if prior low dose exposures at environmental dose levels might ...
Darroudi Firouz - - 2007
We analyzed the phenotype of cells derived from SCID patients with different mutations in the Artemis gene. Using clonogenic survival assay an increased sensitivity was found to X-rays (2-3-fold) and bleomycin (2-fold), as well as to etoposide, camptothecin and methylmethane sulphonate (up to 1.5-fold). In contrast, we did not find ...
Kurvinen Kaisa - - 2006
PURPOSE: Telomerase activation in response to irradiation might enhance the radioresistance of cells. Thus, we have investigated radiation-induced effects on telomerase in six gynecological cancer cell lines, with different intrinsic radiosensitivity and capacity for sublethal damage repair (SLDR). MATERIALS AND METHODS: Three endometrial adenocarcinoma (UM-EC-1, UT-EC-2B and UT-EC-3) and three ...
Ma Yunzhi - - 2006
The study of the radiobiology of boron neutron capture therapy is based on the cellular level dosimetry of boron-10's thermal neutron capture reaction 10B(n,alpha)7Li, in which one 1.47 MeV helium-4 ion and one 0.84 MeV lithium-7 ion are spawned. Because of the chemical preference of boron-10 carrier molecules, the dose ...
Morgan William F - - 2007
Radiation-induced bystander effects refer to those responses occurring in cells that were not subject to energy deposition events following ionizing radiation. These bystander cells may have been neighbors of irradiated cells, or physically separated but subject to soluble secreted signals from irradiated cells. Bystander effects have been observed in vitro ...
Obioha, Fidelis I; University ...
Cells of<i> E.coli</i> B/r were x-irradiated (330Gy) in the presence of oxygen and immediately incubated in a non-lethal concentration of penicillin (10u/ml).This caused enhanced growth of the cell into filaments which later disintegrated (ghosts) and failed to form colonies. Irradiation (950Gy) of these cells under anoxic conditions and incubation in ...
Borgdorff, Viola
In this thesis the role of DNA mismatch repair (MMR) in the cellular response to several genotoxic agents is described. We show that MMR plays an important role in the protection against UVC-induced mutagenesis in mouse embryonic stem (ES) cells. UVC was shown to induce six times more mutations in ...
Berry C C - - 2006
Until now, nanotopography has been considered in 2D construct designs. This has been due to fabrication limitations with traditional lithographic processes relying on the ability to focus radiation that will expose a radiation sensitive resist (e.g. photolithography and electron beam lithography). More recently, alternative methods that offer rapid and cheap ...
Little John B - - 2006
Traditional thinking has been that the biological effects of ionizing radiation occur in irradiated cells as a consequence of the DNA damage they incur. This implies that (1) biological effects occur only in irradiated cells, (2) radiation traversal through the nucleus of the cell is a prerequisite to produce a ...
Urashima Tetsuro - - 2006
To clarify the contribution of apoptosis to cell death in four human solid tumor cell lines, clonogenic cell survival (indicator of radiosensitivity) and induction of caspase-3 (CASP-3)/caspase-3-like proteases (CASP-3LP) and the production of DNA fragmentation (markers for apoptosis) were studied in RKO, LS174T, MCF7 and TE671 cells exposed to DNA-incorporated ...
Hall Zach - - 2007
Johrei has been credited with healing thousands from radiation wounds after the Hiroshima and Nagasaki bombs in 1945. This alternative medical therapy is becoming increasingly popular in the United States, as are other Energy Medicine modalities that purport to influence a universal healing energy. Human brain cells were cultured and ...
Bao Shideng - - 2006
Ionizing radiation represents the most effective therapy for glioblastoma (World Health Organization grade IV glioma), one of the most lethal human malignancies, but radiotherapy remains only palliative because of radioresistance. The mechanisms underlying tumour radioresistance have remained elusive. Here we show that cancer stem cells contribute to glioma radioresistance through ...
Panagopoulos Dimitris J - - 2007
In the present study, the TUNEL (Terminal deoxynucleotide transferase dUTP Nick End Labeling) assay--a well known technique widely used for detecting fragmented DNA in various types of cells--was used to detect cell death (DNA fragmentation) in a biological model, the early and mid stages of oogenesis of the insect Drosophila ...
Ahmad Mansur - - 2007
For successful tissue engineering in surgical radiotherapy patients, irradiated endothelial cells (EC) must form new blood vessels to nourish and build connections with the engineered segment. Therefore, it is critical to understand neovasculogenesis by irradiated EC. The objective of this study was to determine the effects of ionizing radiation on ...
Jaklevic Burnley - - 2006
Cell cycle checkpoints contribute to survival after exposure to ionizing radiation (IR) by arresting the cell cycle and permitting repair. As such, yeast and mammalian cells lacking checkpoints are more sensitive to killing by IR. We reported previously that Drosophila larvae mutant for grp (encoding a homolog of Chk1) survive ...
Lu Hua-Rui - - 2006
Poly(ADP-ribose) polymerase 1 (PARP-1) is involved in multi-pathways to respond to DNA damage. Lack of or inhibition of PARP-1 activity leads to slow progress of cell cycle and sensitization of cells to different stresses. Recently, it was reported that besides the Ku dependent main nonhomologous end joining (NHEJ) pathway, there ...
Rajab Nor F - - 2006
BACKGROUND: Nuclear texture analysis measures phenotypic changes in chromatin distribution within a cell nucleus, while the alkaline Comet assay is a sensitive method for measuring the extent of DNA breakage in individual cells. The authors aim to use both methods to provide information about the sensitivity of cells to ionizing ...
Klising-Sireul Eve - - 2006
Experiments were designed to compare the transcriptional response to ionizing radiation (IR) of wild-type (WT) and ataxia telangiectasia (AT) cells. mRNA levels were assessed 2, 4 and 24 h after exposure to equitoxic doses using cDNA microarrays. Data reveal distinct patterns of gene expression between AT and WT cells since ...
Sutherland John C - - 2006
The probability of survival of cells or viruses exposed to various forms of radiation is expressed as a function of the probability that a given cell will receive a certain number of lethal damages, the average probability that each such damage is repairable, and an upper bound on the repair ...
Balcer-Kubiczek Elizabeth K - - 2007
PURPOSE: The present study was designed to investigate the ability of N-[4-(5-bromo-2-pyrimidyloxy)-3-methylphenyl]-(dimemethylamino)-benzoylphenylurea (dimemethylamino benzoylphenylurea; BPU) to sensitize cells to radiation and to examine the relationship between phenotype versus survival, DNA damage, apoptosis, or cell cycle progression in non-small cell lung cancer (NSCLC) cell lines. METHODS: Asynchronous cultures of three NSCLC ...
Toiyama Yuji - - 2007
AIM: This study was performed to investigate the range of optimal concentration and mechanisms of paclitaxel (PXL) radio-enhancement in gastrointestinal cancer cell lines HT29 and MKN45. METHODS: Cell growth inhibition by PXL pretreatment at various concentrations (0-10 microM) followed by irradiation was investigated using a modified MTT assay. To investigate ...
Zhang Bei - - 2006
The anticancer agent genistein inhibits cell growth of tumor cell lines from various malignancies. In our study, we investigated the effectiveness of combined treatment of ionizing radiation (IR) with genistein on cervical HeLa cells and its possible mechanism. It was found that the inhibitory rate in cells with combined treatment ...
Nylund Reetta - - 2006
We have examined in vitro cell response to mobile phone radiation (900 MHz GSM signal) using two variants of human endothelial cell line: EA.hy926 and EA.hy926v1. Gene expression changes were examined in three experiments using cDNA Expression Arrays and protein expression changes were examined in ten experiments using 2-DE and ...
Okunaga Tomohiro - - 2006
Radiotherapy is the primary and most important adjuvant therapy for malignant gliomas. Although the mechanism of radiation resistance in gliomas has been studied for decades, it is still not clear how the resistance is related with functions of molecular chaperones in the endoplasmic reticulum. Calreticulin (CRT) is a Ca(2+)-binding molecular ...
Ohnishi Ken - - 2006
NBS1 is essential for the repair of radiation-induced DNA double-strand breaks (DSBs) in yeast and higher vertebrate cells. In this study, we examined whether suppressed NBS1 expression by small interference RNA (siRNA) could enhance radiation sensitivity in cancer cells with different TP53 status. We used human non-small cell lung cancer ...
Whitehead Timothy D - - 2006
Experiments with cultured C3H 10T 1/2 cells were performed to determine if exposure to cell phone radiofrequency (RF) radiations induce changes in gene expression. Following a 24 h exposure of 5 W/kg specific adsorption rate, RNA was extracted from the exposed and sham control cells for microarray analysis on Affymetrix ...
Hu Meiduo - - 2006
In this study, we evaluated the ability of anti-p21 antibodies conjugated to 17-mer peptides [GRKKRRQRRRPPQGYGC] harboring the membrane-translocating and nuclear import sequences [underlined] of HIV-1 tat protein to inhibit the cyclin-dependent kinase inhibitor, p21(WAF-1/Cip-1) (p21) and differentially sensitize MDA-MB-468 and MCF-7 human breast cancer (BC) cells to the antiproliferative effects ...
Alonso-Sáez Laura - - 2006
We studied the effects of natural sunlight on heterotrophic marine bacterioplankton in short-term experiments. We used a single-cell level approach involving flow cytometry combined with physiological probes and microautoradiography to determine sunlight effects on the activity and integrity of the cells. After 4 h of sunlight exposure, most bacterial cells ...
Adhikari, J. S.
The AT specific minor grove DNA binding ligands bisbenzimidazole derivatives like hoechst-33342 and hoechst-33258 which scavenge free radicals and stabilize macromolecular structure have been shown to afford radioprotection by reducing the induction of DNA damage. However, their ability to inhibit topoisomerases I & II, which play important roles in damage ...
Vorotnikova Ekaterina - - 2006
PURPOSE: The purpose of the study was to examine the optimal time of exposure and dose of heat and ionizing radiation that results in the killing of human cancer cells in vitro via apoptosis vs. necrosis. MATERIALS AND METHODS: Human mammary carcinoma, colorectal carcinoma and normal bovine capillary endothelial (BCE) ...
Chakravarti Arnab - - 2006
PURPOSE: In this study, we investigated the mechanisms by which temozolomide enhances radiation response in glioblastoma cells. EXPERIMENTAL DESIGN: Using a panel of four primary human glioblastoma cell lines with heterogeneous O(6)-methylguanine-DNA methyltransferase (MGMT) protein expression, normal human astrocytes, and U87 xenografts, we investigated (a) the relationship of MGMT status ...
Hau Pok Man - - 2006
Polyploidization occurs during normal development as well as during tumorigenesis. In this study, we investigated if the responses to genotoxic stress in cancer cells are influenced by the ploidy. Prolonged treatment of Hep3B cells with the spindle inhibitor nocodazole resulted in mitotic slippage, followed by re-replication of the DNA to ...
Laptev R - - 2006
Photodynamic therapy (PDT) involves a two-stage process. A light-absorbing photosensitiser (Ps) is endocytosed and then stimulated by light, inducing transfer of energy to a cytoplasmic acceptor molecule and the generation of reactive oxygen species that initiate damage to cellular membrane components and cytolysis. The expanded use of PDT in the ...
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