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[PMID]:27770746
[Au] Autor:Poongavanam V; Kongsted J
[Ad] Endereço:Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense M, Denmark.
[Ti] Título:Binding affinity models for Falcipain inhibition based on the Linear Interaction Energy method.
[So] Source:J Mol Graph Model;70:236-245, 2016 11.
[Is] ISSN:1873-4243
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The high rate of drug resistance as well as the complex biochemical process of the parasite reproduction cycle makes development of new drugs for malaria a very important but challenging task. Falcipain 2 (FL2) and Falcipain 3 (FL3) are the major cysteine protease enzymes that play a central role in providing essential amino acids for the parasite's protein biosynthesis through the hemoglobin hydrolysis process. Selective inhibition of these enzymes is considered as a promising chemotherapeutic target. In the present investigation, the highly efficient linear interaction energy (LIE) method has been parameterized for binding affinity predictions and assessed with a set of 244 compounds for FL2 and FL3 inhibition. The results revealed that the van der Waals energy is very important for ligands binding to Falcipain proteins and that, overall, the electrostatic energy contribution is minor. The best models obtained for FL2 and FL3 give root mean square errors (RMSE) of 1.82 and 1.33kcal/mol respectively, for the test set. In this study, we also investigate how the choice of initial protein-ligand confirmation (pose) impacts the overall quality of the LIE models. Moreover, the transferability of LIE parameters is further discussed.
[Mh] Termos MeSH primário: Cisteína Endopeptidases/química
Cisteína Endopeptidases/farmacologia
Transferência Linear de Energia
Modelos Moleculares
[Mh] Termos MeSH secundário: Ligantes
Simulação de Acoplamento Molecular
Análise Multivariada
Análise de Componente Principal
Pirimidinas/química
Reprodutibilidade dos Testes
Termodinâmica
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Ligands); 0 (Pyrimidines); EC 3.4.22.- (Cysteine Endopeptidases); EC 3.4.22.- (falcipain); EC 3.4.22.- (falcipain 2); EC 3.4.22.- (falcipain 3)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180216
[Lr] Data última revisão:
180216
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161023
[St] Status:MEDLINE


  2 / 2407 MEDLINE  
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[PMID]:28464743
[Au] Autor:Dahle TJ; Rykkelid AM; Stokkevåg CH; Mairani A; Görgen A; Edin NJ; Rørvik E; Fjæra LF; Malinen E; Ytre-Hauge KS
[Ad] Endereço:a Department of Physics and Technology , University of Bergen , Bergen , Norway.
[Ti] Título:Monte Carlo simulations of a low energy proton beamline for radiobiological experiments.
[So] Source:Acta Oncol;56(6):779-786, 2017 Jun.
[Is] ISSN:1651-226X
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: In order to determine the relative biological effectiveness (RBE) of protons with high accuracy, radiobiological experiments with detailed knowledge of the linear energy transfer (LET) are needed. Cell survival data from high LET protons are sparse and experiments with low energy protons to achieve high LET values are therefore required. The aim of this study was to quantify LET distributions from a low energy proton beam by using Monte Carlo (MC) simulations, and to further compare to a proton beam representing a typical minimum energy available at clinical facilities. MATERIALS AND METHODS: A Markus ionization chamber and Gafchromic films were employed in dose measurements in the proton beam at Oslo Cyclotron Laboratory. Dose profiles were also calculated using the FLUKA MC code, with the MC beam parameters optimized based on comparisons with the measurements. LET spectra and dose-averaged LET (LET ) were then estimated in FLUKA, and compared with LET calculated from an 80 MeV proton beam. RESULTS: The initial proton energy was determined to be 15.5 MeV, with a Gaussian energy distribution of 0.2% full width at half maximum (FWHM) and a Gaussian lateral spread of 2 mm FWHM. The LET increased with depth, from approximately 5 keV/µm in the entrance to approximately 40 keV/µm in the distal dose fall-off. The LET values were considerably higher and the LET spectra were much narrower than the corresponding spectra from the 80 MeV beam. CONCLUSIONS: MC simulations accurately modeled the dose distribution from the proton beam and could be used to estimate the LET at any position in the setup. The setup can be used to study the RBE for protons at high LET , which is not achievable in clinical proton therapy facilities.
[Mh] Termos MeSH primário: Sobrevivência Celular/efeitos da radiação
Simulação por Computador
Método de Monte Carlo
Prótons
Radiobiologia
[Mh] Termos MeSH secundário: Seres Humanos
Transferência Linear de Energia
Eficiência Biológica Relativa
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Protons)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180213
[Lr] Data última revisão:
180213
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170504
[St] Status:MEDLINE
[do] DOI:10.1080/0284186X.2017.1289239


  3 / 2407 MEDLINE  
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[PMID]:28741678
[Au] Autor:Hu W; Li W; Chen J
[Ad] Endereço:Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.
[Ti] Título:Recent advances of microbial breeding via heavy-ion mutagenesis at IMP.
[So] Source:Lett Appl Microbiol;65(4):274-280, 2017 Oct.
[Is] ISSN:1472-765X
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Nowadays, the value of heavy-ion mutagenesis has been accepted as a novel powerful mutagen technique to generate new microbial mutants due to its high linear energy transfer and high relative biological effectiveness. This paper briefly reviews recent progress in developing a more efficient mutagenesis technique for microbial breeding using heavy-ion mutagenesis, and also presents the outline of the beam line for microbial breeding in Heavy Ion Research Facility of Lanzhou. Then, new insights into microbial biotechnology via heavy-ion mutagenesis are also further explored. We hope that our concerns will give deep insight into microbial breeding biotechnology via heavy-ion mutagenesis. We also believe that heavy-ion mutagenesis breeding will greatly contribute to the progress of a comprehensive study industrial strain engineering for bioindustry in the future. SIGNIFICANCE AND IMPACT OF THE STUDY: There is currently a great interest in developing rapid and diverse microbial mutation tool for strain modification. Heavy-ion mutagenesis has been proved as a powerful technology for microbial breeding due to its broad spectrum of mutation phenotypes with high efficiency. In order to deeply understand heavy-ion mutagenesis technology, this paper briefly reviews recent progress in microbial breeding using heavy-ion mutagenesis at IMP, and also presents the outline of the beam line for microbial breeding in Heavy Ion Research Facility of Lanzhou (HIRFL) as well as new insights into microbial biotechnology via heavy-ion mutagenesis. Thus, this work can provide the guidelines to promote the development of novel microbial biotechnology cross-linking heavy-ion mutagenesis breeding that could make breeding process more efficiently in the future.
[Mh] Termos MeSH primário: Aspergillus/genética
Clostridium/genética
Íons Pesados
Transferência Linear de Energia/fisiologia
Microalgas/genética
Mutagênese/genética
Trichoderma/genética
[Mh] Termos MeSH secundário: Aspergillus/efeitos da radiação
Cruzamento
Clostridium/efeitos da radiação
Microalgas/efeitos da radiação
Mutação/genética
Fenótipo
Radiação Ionizante
Trichoderma/efeitos da radiação
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180104
[Lr] Data última revisão:
180104
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170726
[St] Status:MEDLINE
[do] DOI:10.1111/lam.12780


  4 / 2407 MEDLINE  
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[PMID]:28910671
[Au] Autor:Bláha P; Koshlan NA; Koshlan IV; Petrova DV; Bogdanova YV; Govorun RD; Múcka V; Krasavin EA
[Ad] Endereço:Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Joliot--Curie 6, 141980, Dubna, Moscow Region, Russia; Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Brehová 7, 11519, Prague 1, Czech Republic. Electronic address: pavel.blahax@gmail
[Ti] Título:Delayed effects of accelerated heavy ions on the induction of HPRT mutations in V79 hamster cells.
[So] Source:Mutat Res;803-805:35-41, 2017 Oct.
[Is] ISSN:1873-135X
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Fundamental research on the harmful effects of ionizing radiation on living cells continues to be of great interest. Recently, priority has been given to the study of high-charge and high-energy (HZE) ions that comprise a substantial part of the galactic cosmic ray (GCR) spectra that would be encountered during long-term space flights. Moreover, predictions of the delayed genetic effects of high linear energy transfer (LET) exposure is becoming more important as heavy ion therapy use is increasing. This work focuses mainly on the basic research on the delayed effects of HZE ions on V79 Chinese hamster cells, with emphasis on the induction of HPRT mutations after prolonged expression times (ET). The research was conducted under various irradiation conditions with accelerated ions O (E=35.2MeV/n), Ne (E=47.7MeV/n and 51.8MeV/n), and B (E=32.4MeV/n), with LET in the range from 49 to 149 keV/µm and with Co γ-rays. The HPRT mutant fractions (MF) were detected in irradiated cells in regular intervals during every cell culture recultivation (every 3days) up to approximately 40days (70-80 generations) after irradiation. The MF maximum was reached at different ET depending on ionizing radiation characteristics. The position of the maximum was shifting towards longer ET with increasing LET. We speculate that the delayed mutations are created de novo and that they are the manifestation of genomic instability. Although the exact mechanisms involved in genomic instability initiation are yet to be identified, we hypothesize that differences in induction of delayed mutations by radiations with various LET values are related to variations in energy deposition along the particle track. A dose dependence of mutation yield is discussed as well.
[Mh] Termos MeSH primário: Raios gama
Íons Pesados/efeitos adversos
Hipoxantina Fosforribosiltransferase/genética
Mutação
[Mh] Termos MeSH secundário: Animais
Linhagem Celular
Cricetinae
Cricetulus
Relação Dose-Resposta à Radiação
Fibroblastos/efeitos da radiação
Instabilidade Genômica/efeitos da radiação
Transferência Linear de Energia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
EC 2.4.2.8 (Hypoxanthine Phosphoribosyltransferase)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171011
[Lr] Data última revisão:
171011
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170915
[St] Status:MEDLINE


  5 / 2407 MEDLINE  
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[PMID]:28871980
[Au] Autor:Mohan R; Das IJ; Ling CC
[Ad] Endereço:Department of Radiation Physics, MD Anderson Cancer Center, Houston, Texas. Electronic address: rmohan@mdanderson.org.
[Ti] Título:Empowering Intensity Modulated Proton Therapy Through Physics and Technology: An Overview.
[So] Source:Int J Radiat Oncol Biol Phys;99(2):304-316, 2017 Oct 01.
[Is] ISSN:1879-355X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Considering the clinical potential of protons attributable to their physical characteristics, interest in proton therapy has increased greatly in this century, as has the number of proton therapy installations. Until recently, passively scattered proton therapy was used almost entirely. Notably, the overall clinical results to date have not shown a convincing benefit of protons over photons. A rapid transition is now occurring with the implementation of the most advanced form of proton therapy, intensity modulated proton therapy (IMPT). IMPT is superior to passively scattered proton therapy and intensity modulated radiation therapy (IMRT) dosimetrically. However, numerous limitations exist in the present IMPT methods. In particular, compared with IMRT, IMPT is highly vulnerable to various uncertainties. In this overview we identify three major areas of current limitations of IMPT: treatment planning, treatment delivery, and motion management, and discuss current and future efforts for improvement. For treatment planning, we need to reduce uncertainties in proton range and in computed dose distributions, improve robust planning and optimization, enhance adaptive treatment planning and delivery, and consider how to exploit the variability in the relative biological effectiveness of protons for clinical benefit. The quality of proton therapy also depends on the characteristics of the IMPT delivery systems and image guidance. Efforts are needed to optimize the beamlet spot size for both improved dose conformality and faster delivery. For the latter, faster energy switching time and increased dose rate are also needed. Real-time in-room volumetric imaging for guiding IMPT is in its early stages with cone beam computed tomography (CT) and CT-on-rails, and continued improvements are anticipated. In addition, imaging of the proton beams themselves, using, for instance, prompt γ emissions, is being developed to determine the proton range and to reduce range uncertainty. With the realization of the advances described above, we posit that IMPT, thus empowered, will lead to substantially improved clinical results.
[Mh] Termos MeSH primário: Movimento
Terapia com Prótons/métodos
Planejamento da Radioterapia Assistida por Computador
Radioterapia de Intensidade Modulada/métodos
Tecnologia Radiológica
[Mh] Termos MeSH secundário: Física Sanitária
Seres Humanos
Transferência Linear de Energia
Neoplasias/diagnóstico por imagem
Neoplasias/radioterapia
Terapia com Prótons/normas
Terapia com Prótons/tendências
Qualidade da Assistência à Saúde
Dosagem Radioterapêutica
Planejamento da Radioterapia Assistida por Computador/normas
Radioterapia Guiada por Imagem
Radioterapia de Intensidade Modulada/normas
Radioterapia de Intensidade Modulada/tendências
Eficiência Biológica Relativa
Respiração
Incerteza
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Em] Mês de entrada:1709
[Cu] Atualização por classe:171024
[Lr] Data última revisão:
171024
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170906
[St] Status:MEDLINE


  6 / 2407 MEDLINE  
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[PMID]:28863396
[Au] Autor:Tello Cajiao JJ; Carante MP; Bernal Rodriguez MA; Ballarini F
[Ad] Endereço:University of Pavia, Physics Department, via Bassi 6, I-27100 Pavia, Italy; INFN-Sezione di Pavia, via Bassi 6, I-27100 Pavia, Italy; Universidade Estadual de Campinas. Cidade Universitária Zeferino Vaz, Campinas, SP, Brazil. Electronic address: fisk2190@gmail.com.
[Ti] Título:Proximity effects in chromosome aberration induction by low-LET ionizing radiation.
[So] Source:DNA Repair (Amst);58:38-46, 2017 Oct.
[Is] ISSN:1568-7856
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Although chromosome aberrations are known to derive from distance-dependent mis-rejoining of chromosome fragments, evaluating whether a certain model describes such "proximity effects" better than another one is complicated by the fact that different approaches have often been tested under different conditions. Herein, a biophysical model ("BIANCA", i.e. BIophysical ANalysis of Cell death and chromosome Aberrations) was upgraded, implementing explicit chromosome-arm domains and two new models for the dependence of the rejoining probability on the fragment initial distance, r. Such probability was described either by an exponential function like exp(-r/r ), or by a Gaussian function like exp(-r /2σ ), where r and σ were adjustable parameters. The second, and last, parameters was the yield of "Cluster Lesions" (CL), where "Cluster Lesion" defines a critical DNA damage producing two independent chromosome fragments. The model was applied to low-LET-irradiated lymphocytes (doses: 1-4Gy) and fibroblasts (1-6.1Gy). Good agreement with experimental yields of dicentrics and centric rings, and thus their ratio ("F-ratio"), was found by both the exponential model (with r =0.8µm for lymphocytes and 0.7µm for fibroblasts) and the Gaussian model (with σ=1.1µm for lymphocytes and 1.3µm for fibroblasts). While the former also allowed reproducing dose-responses for excess acentric fragments, the latter substantially underestimated the experimental curves. Both models provided G-ratios (ratio of acentric to centric rings) higher than those expected from randomness, although the values calculated by the Gaussian model were lower than those calculated by the exponential one. For lymphocytes the calculated G-ratios were in good agreement with the experimental ones, whereas for fibroblasts both models substantially underestimated the experimental results, which deserves further investigation. This work suggested that, although both models performed better than a step model (which previously allowed reproducing the F-ratio but underestimated the G-ratio), an exponential function describes proximity effects better than a Gaussian one.
[Mh] Termos MeSH primário: Núcleo Celular/efeitos da radiação
Aberrações Cromossômicas
Radiação Ionizante
[Mh] Termos MeSH secundário: Núcleo Celular/genética
DNA/efeitos da radiação
Dano ao DNA
Fibroblastos/efeitos da radiação
Seres Humanos
Transferência Linear de Energia
Linfócitos/efeitos da radiação
Modelos Biológicos
Método de Monte Carlo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
9007-49-2 (DNA)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171010
[Lr] Data última revisão:
171010
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170902
[St] Status:MEDLINE


  7 / 2407 MEDLINE  
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[PMID]:28753066
[Au] Autor:Werner E; Wang Y; Doetsch PW
[Ad] Endereço:Department of a Biochemistry, Emory University School of Medicine, Atlanta, Georgia.
[Ti] Título:A Single Exposure to Low- or High-LET Radiation Induces Persistent Genomic Damage in Mouse Epithelial Cells In Vitro and in Lung Tissue.
[So] Source:Radiat Res;188(4):373-380, 2017 Oct.
[Is] ISSN:1938-5404
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Exposures to low- and high-linear energy transfer (LET) radiation induce clustered damage in DNA that is difficult to repair. These lesions are manifested as DNA-associated foci positive for DNA repair proteins and have been shown to persist in vitro and in vivo for days in several cell types and tissues in response to low-LET radiation. Although in some experimental conditions these residual foci have been linked with genomic instability and chromosomal aberrations, it remains poorly understood what type of damage they represent. Because high-LET radiation induces complex DNA lesions more efficiently than low-LET radiation, we compared the efficacy of several heavy ions (oxygen, silicon and iron) in a range (17 , 70 and 175 keV/µm, respectively) of LET and X rays at a 1 Gy dose. Persistent genomic damage was measured by γ-H2AX-53BP1-positive residual foci and micronucleus levels during the first three days and up to a week after in vitro and in vivo irradiation in lung cells and tissue. We demonstrate that in an in vitro irradiated mouse bronchial epithelial cell line, the expression of residual foci is readily detectable at 24 h with levels declining in the following 72 h postirradiation, but still persisting elevated over background at day 7. At this time, foci numbers are low but significant and proportional to the dose and quality of the radiation. The expression of residual foci in vitro was mirrored by increased micronuclei generation measured in cytokinesis-blocked cells, indicating long-term, persistent effects of genomic damage in this cell type. We also tested the expression of residual foci in lung tissue of C57BL/6 mice that received whole-body X-ray or heavy-ion irradiation. We found that at day 7 postirradiation, Clara/Club cells, but not pro-SPC-positive pneumocytes, contained a subpopulation of cells expressing γ-H2AX-53BP1-positive foci in a radiation quality-dependent manner. These findings suggest that in vivo persistent DNA repair foci reflect the initial genotoxic damage induced by radiation and a differential vulnerability among cells in the lung.
[Mh] Termos MeSH primário: Células Epiteliais/metabolismo
Células Epiteliais/efeitos da radiação
Genômica
Transferência Linear de Energia
Pulmão/metabolismo
Pulmão/efeitos da radiação
[Mh] Termos MeSH secundário: Animais
Linhagem Celular
Relação Dose-Resposta à Radiação
Feminino
Camundongos
Camundongos Endogâmicos C57BL
Fenótipo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171017
[Lr] Data última revisão:
171017
[Sb] Subgrupo de revista:IM; S
[Da] Data de entrada para processamento:170729
[St] Status:MEDLINE
[do] DOI:10.1667/RR14685.1


  8 / 2407 MEDLINE  
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[PMID]:28732021
[Au] Autor:Chan HS; de Blois E; Morgenstern A; Bruchertseifer F; de Jong M; Breeman W; Konijnenberg M
[Ad] Endereço:Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands.
[Ti] Título:In Vitro comparison of 213Bi- and 177Lu-radiation for peptide receptor radionuclide therapy.
[So] Source:PLoS One;12(7):e0181473, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Absorbed doses for α-emitters are different from those for ß-emitters, as the high linear energy transfer (LET) nature of α-particles results in a very dense energy deposition over a relatively short path length near the point of emission. This highly localized and therefore high energy deposition can lead to enhanced cell-killing effects at absorbed doses that are non-lethal in low-LET type of exposure. Affinities of DOTA-DPhe1-Tyr3-octreotate (DOTATATE), 115In-DOTATATE, 175Lu-DOTATATE and 209Bi-DOTATATE were determined in the K562-SST2 cell line. Two other cell lines were used for radiation response assessment; BON and CA20948, with a low and high expression of somatostatin receptors, respectively. Cellular uptake kinetics of 111In-DOTATATE were determined in CA20948 cells. CA20948 and BON were irradiated with 137Cs, 177Lu-DTPA, 177Lu-DOTATATE, 213Bi-DTPA and 213Bi-DOTATATE. Absorbed doses were calculated using the MIRDcell dosimetry method for the specific binding and a Monte Carlo model of a cylindrical 6-well plate geometry for the exposure by the radioactive incubation medium. Absorbed doses were compared to conventional irradiation of cells with 137Cs and the relative biological effect (RBE) at 10% survival was calculated. RESULTS: IC50 of (labelled) DOTATATE was in the nM range. Absorbed doses up to 7 Gy were obtained by 5.2 MBq 213Bi-DOTATATE, in majority the dose was caused by α-particle radiation. Cellular internalization determined with 111In-DOTATATE showed a linear relation with incubation time. Cell survival after exposure of 213Bi-DTPA and 213Bi-DOTATATE to BON or CA20948 cells showed a linear-exponential relation with the absorbed dose, confirming the high LET character of 213Bi. The survival of CA20948 after exposure to 177Lu-DOTATATE and the reference 137Cs irradiation showed the typical curvature of the linear-quadratic model. 10% Cell survival of CA20948 was reached at 3 Gy with 213Bi-DOTATATE, a factor 6 lower than the 18 Gy found for 177Lu-DOTATATE and also below the 5 Gy after 137Cs external exposure. CONCLUSION: 213Bi-DTPA and 213Bi-DOTATATE lead to a factor 6 advantage in cell killing compared to 177Lu-DOTATATE. The RBE at 10% survival by 213Bi-ligand compared to 137Cs was 2.0 whereas the RBE for 177Lu-DOTATATE was 0.3 in the CA20948 in vitro model.
[Mh] Termos MeSH primário: Absorção de Radiação
Bismuto
Lutécio
Octreotida/análogos & derivados
Octreotida/farmacologia
Radioisótopos
Compostos Radiofarmacêuticos
Receptores de Somatostatina/metabolismo
[Mh] Termos MeSH secundário: Linhagem Celular Tumoral
Sobrevivência Celular/efeitos da radiação
Relação Dose-Resposta à Radiação
Seres Humanos
Cinética
Transferência Linear de Energia
Modelos Biológicos
Método de Monte Carlo
Compostos Organometálicos/administração & dosagem
Compostos Organometálicos/farmacologia
Radioisótopos/administração & dosagem
Radioisótopos/farmacocinética
Radiometria
Compostos Radiofarmacêuticos/administração & dosagem
Compostos Radiofarmacêuticos/farmacocinética
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Organometallic Compounds); 0 (Radioisotopes); 0 (Radiopharmaceuticals); 0 (Receptors, Somatostatin); 0 (somatostatin receptor subtype 2, human); 5H0DOZ21UJ (Lutetium); RWM8CCW8GP (Octreotide); U015TT5I8H (Bismuth)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171002
[Lr] Data última revisão:
171002
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170722
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0181473


  9 / 2407 MEDLINE  
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[PMID]:28658060
[Au] Autor:Sasaki M
[Ad] Endereço:*Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry, 2-11-1 Iwado kita, Komae-shi, Tokyo 201-8511 Japan.
[Ti] Título:Photon-Fluence-Weighted let for Radiation Fields Subjected to Epidemiological Studies.
[So] Source:Health Phys;113(2):143-148, 2017 Aug.
[Is] ISSN:1538-5159
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:In order to estimate the uncertainty of the radiation risk associated with the photon energy in epidemiological studies, photon-fluence-weighted LET values were quantified for photon radiation fields with the target organs and irradiation conditions taken into consideration. The photon fluences giving a unit absorbed dose to the target organ were estimated by using photon energy spectra together with the dose conversion coefficients given in ICRP Publication 116 for the target organs of the colon, bone marrow, stomach, lung, skin and breast with three irradiation geometries. As a result, it was demonstrated that the weighted LET values did not show a clear difference among the photon radiation fields subjected to epidemiological studies, regardless of the target organ and the irradiation geometry.
[Mh] Termos MeSH primário: Estudos Epidemiológicos
Transferência Linear de Energia/fisiologia
Modelos Biológicos
Fótons
Vísceras/fisiologia
Contagem Corporal Total/métodos
[Mh] Termos MeSH secundário: Absorção de Radiação/fisiologia
Adulto
Simulação por Computador
Feminino
Seres Humanos
Masculino
Especificidade de Órgãos/fisiologia
Dose de Radiação
Exposição à Radiação/análise
Eficiência Biológica Relativa
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170818
[Lr] Data última revisão:
170818
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170629
[St] Status:MEDLINE
[do] DOI:10.1097/HP.0000000000000683


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[PMID]:28650774
[Au] Autor:Emfietzoglou D; Papamichael G; Nikjoo H
[Ad] Endereço:a Medical Physics Laboratory, University of Ioannina Medical School, Ioannina 45110, Greece.
[Ti] Título:Monte Carlo Electron Track Structure Calculations in Liquid Water Using a New Model Dielectric Response Function.
[So] Source:Radiat Res;188(3):355-368, 2017 Sep.
[Is] ISSN:1938-5404
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Monte Carlo track structure codes provide valuable information for understanding radiation effects down to the DNA level, where experimental measurements are most difficult or unavailable. It is well recognized that the performance of such codes, especially at low energies and/or subcellular level, critically depends on the reliability of the interaction cross sections that are used as input in the simulation. For biological media such as liquid water, one of the most challenging issues is the role of condensed-phase effects. For inelastic scattering, such effects can be conveniently accounted for through the complex dielectric response function of the media. However, for this function to be useful it must fulfill some important sum rules and have a simple analytic form for arbitrary energy- and momentum-transfer. The Emfietzoglou-Cucinotta-Nikjoo (ECN) model offers a practical, self-consistent and fully analytic parameterization of the dielectric function of liquid water based on the best available experimental data. An important feature of the ECN model is that it includes, in a phenomenological manner, exchange and correlation effects among the screening electrons, thus, going beyond the random-phase approximation implicit in earlier models. In this work, inelastic cross sections beyond the plane wave Born approximation are calculated for low-energy electrons (10 eV-10 keV) based on the ECN model, and used for Monte Carlo track structure simulations of physical quantities relevant to the microdosimetry of low-energy electrons in liquid water. Important new developments in the physics of inelastic scattering are discussed and their effect on electron track structure is investigated by a comparison against simulations (under otherwise identical conditions) using the Born approximation and a simpler form of the dielectric function based on the Oak Ridge National Laboratory model. The results reveal that both the dielectric function and the corrections to the Born approximation may have a sizeable effect on track structure calculations at the nanometer scale (DNA level), where the details of inelastic scattering and the role of low-energy electrons are most critical.
[Mh] Termos MeSH primário: Elétrons
Transferência Linear de Energia
Modelos Químicos
Modelos Estatísticos
Espalhamento de Radiação
Água/química
[Mh] Termos MeSH secundário: Simulação por Computador
Modelos Biológicos
Dose de Radiação
Reprodutibilidade dos Testes
Sensibilidade e Especificidade
Soluções
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Solutions); 059QF0KO0R (Water)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170919
[Lr] Data última revisão:
170919
[Sb] Subgrupo de revista:IM; S
[Da] Data de entrada para processamento:170627
[St] Status:MEDLINE
[do] DOI:10.1667/RR14705.1



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