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1.
Biomed Environ Sci ; 33(8): 603-613, 2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-32933612

RESUMO

Objective: To detect the effects of shortwave radiation on dose-dependent cardiac structure and function in rats after radiation and to elucidate the mechanism of shortwave radiation induced cardiac injury to identify sensitive indicators and prophylactic treatment. Methods: One hundred Wistar rats were either exposed to 27 MHz continuous shortwave at a power density of 5, 10, and 30 mW/cm 2 for 6 min or undergone sham exposure for the control (the rats had to be placed in the exposure system with the same schedules as the exposed animals, but with an inactive antenna). The Ca 2+, glutamic oxaloacetic transaminase (AST), creatine kinase (CK) and lactate dehydrogenase (LDH) content in the peripheral serum of the rats were detected by an automatic blood biochemical analyser. The electrocardiogram (ECG) of standard lead II was recorded by a multi-channel physiological recording and analysis system. The cardiac structure of rats was observed by light and electron microscopy. Results: The results showed that the 5, 10, and 30 mW/cm 2 shortwave radiation caused a significant increased in the levels of Ca 2+, AST, CK, and LDH in the peripheral serum of rats. The cardiac structure was damaged by radiation and showed a disordered arrangement of myocardial fibres, the cavitation and swelling of myocardial mitochondria. These injuries were most significant 7 d after radiation and were not restored until 28 d after radiation. Conclusion: Shortwave radiation of 5, 10, and 30 mW/cm 2 can damage rat cardiac function, including damage to the tissue structure and ultrastructure, especially at the level of the myocardial fibres and mitochondria. Shortwave radiation at 5, 10, and 30 mW/cm 2 induced damage to rat heart function and structure with a dose-effect relationship, i.e., the greater the radiation dose was, the more significant the damage was.


Assuntos
Cardiopatias/patologia , Coração/efeitos da radiação , Miocárdio/patologia , Ondas de Rádio/efeitos adversos , Animais , Relação Dose-Resposta à Radiação , Cardiopatias/etnologia , Cardiopatias/fisiopatologia , Masculino , Distribuição Aleatória , Ratos , Ratos Wistar
2.
Anticancer Res ; 40(10): 5497-5502, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32988872

RESUMO

BACKGROUND/AIM: The cell-killing and radiosensitizing effects of carbon-ion (C-ion) beams with low linear energy transfer (LET) are underexplored. We aimed to demonstrate the cell-killing effects of 60Co gamma rays and C-ion beams at various LET values and the radiosensitizing effect of C-ion beams at various LET and cisplatin levels. MATERIALS AND METHODS: Human uterine cervical cancer cells were irradiated with 60Co gamma rays and C-ion beams at different levels of LET, with and without cisplatin treatment. RESULTS: Low-LET C-ion beams had a superior cell-killing effect compared to 60Co gamma rays. Survival curves under low-LET C-ion beams were more similar to that of 60Co gamma rays than that of high-LET C-ion beams. Cisplatin significantly reduced cell survival after 1, 2, and 3 Gy C-ion beam irradiations at LET values of 13/30/70 keV/µm, 13/30 keV/µm, and 13 keV/µm, respectively. CONCLUSION: Low-LET C-ion beams combined with cisplatin have higher radiosensitizing effects than high-LET C-ion beams.


Assuntos
Carbono/uso terapêutico , Radioisótopos de Cobalto/uso terapêutico , Radiossensibilizantes/uso terapêutico , Neoplasias do Colo do Útero/radioterapia , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Cisplatino/farmacologia , Relação Dose-Resposta à Radiação , Feminino , Raios gama , Humanos , Transferência Linear de Energia/efeitos da radiação , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/patologia
3.
Anticancer Res ; 40(10): 5901-5907, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32988921

RESUMO

BACKGROUND/AIM: To assess predictors of local control (LC) for stereotactic ablative radiotherapy (SAbR) in pulmonary oligometastatic disease (OMD) from gastrointestinal (GI) malignancies. PATIENTS AND METHODS: Patients with pulmonary OMD treated with SAbR from January 2016 to December 2018 were included in this observational analysis. Primary endpoint was LC. Uni- and multivariate analyses to assess variable correlations were conducted. RESULTS: Thirty-seven patients and 59 lung metastases were evaluated. The delivered dose was 30-60 Gy in 3-8 fractions. After a median follow-up of 23.0 months (range=6.3-50.4 months), LC rate at 1/2 years was 89.7%/85.0%, and increased to 96.0%/91.0% for lesions treated with a biologically effective dose (BED10) ≥100 Gy (p=0.03). RECIST response at 6 months was predictive for LC (p=0.002). CONCLUSION: SAbR is an effective option for pulmonary OMD from GI malignancies. A BED10 ≥100 Gy and radiological response at 6 months can affect LC.


Assuntos
Neoplasias Gastrointestinais/radioterapia , Neoplasias Gastrointestinais/cirurgia , Neoplasias Pulmonares/radioterapia , Neoplasias Pulmonares/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Relação Dose-Resposta à Radiação , Feminino , Neoplasias Gastrointestinais/patologia , Humanos , Neoplasias Pulmonares/secundário , Masculino , Pessoa de Meia-Idade , Radiocirurgia/métodos
4.
J Environ Radioact ; 222: 106320, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32892896

RESUMO

The effects of radiation on radial growth of Scots pine (Pinus sylvestris L.) affected by the Chernobyl accident were studied at five sites with different deposition levels. The study sites were chosen along a high gradient of depositions at the distance of a few hundred meters in the forests with similar forest characteristics. Air dose rates varied at the sites from the background values up to 30 µGy h-1 as of December 1, 2016. Scots pine trees exposed to sub-lethal doses of 8.6-13.2 Gy at the "Red Forest" site did not demonstrate deviations in formation of annual rings 30 years after the Chernobyl accident compared to trees with lower doses and control trees. Variation with time in annual rings thickness did reveal that the effect of radiation in trees growing at the sites with different contamination not detectable in 1986 and 1987. Conversely, the effects were clear observed in a later period in 1989-1991, i.e. 3-5 years after the accident. Until 2000, there were statistically significant differences in the annual rings growth rates of Scots pine trees exposed to external absorbed dose rates of 4.4-6.7 mGy h-1 as estimated for June 1, 1986 (or 19.5-30.0 µGy h-1 as of December 1, 2016) compared with the trees of the other sites studied. The results comply with the conclusions from research with acute pine exposure conducted in the Kyshtym area in 1975-1984.


Assuntos
Acidente Nuclear de Chernobyl , Pinus sylvestris , Monitoramento de Radiação , Relação Dose-Resposta à Radiação , Pinus sylvestris/crescimento & desenvolvimento
5.
Medicine (Baltimore) ; 99(31): e21333, 2020 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-32756119

RESUMO

This study aimed to evaluate the imaging findings and prognostic factors after whole-brain radiotherapy in patients with carcinomatous meningitis from breast cancer.A retrospective analysis of imaging data and prognostic factors was performed in patients treated with whole-brain radiotherapy or whole-brain/spine radiotherapy immediately after the first diagnosis of carcinomatous meningitis from breast cancer at our hospital from January 1, 2010 to December 31, 2018. Statistical significance was set at P < .05 (two-tailed).All patients (n = 31) were females with the mean age of 58.0 ±â€Š11.0 years. The breast cancer subtypes were luminal (n = 14, 45.1%), human epidermal growth factor receptor 2 (HER2)-positive (n = 9, 29.0%), and triple-negative (n = 8, 26.0%) breast cancer. Brain metastasis and abnormal contrast enhancement in the sulci were observed in 21 (67.7%) and 24 (80.6%) patients, respectively. The median survival time after cancerous meningitis diagnosis was 62 (range, 6-657) days. Log-rank test showed significant differences in median survival time after cancerous meningitis diagnosis: 18.0 days for subjects treated with 30 Gy in < 10 fractions (n = 7) vs 78.5 days for subjects treated with 30 Gy in ≥10 fractions (n = 24) (P < .01) and 23.0 days for the triple-negative subtype vs 78.5 days for the other subtype (P < .01) groups. Univariate analysis using the Cox regression model showed significant differences in median survival time after cancerous meningitis diagnosis between the group treated with 30 Gy in <10 fractions and the group treated in ≥10 fractions (hazard ratio [HR] 0.08, 95% confidence interval [CI], 0.03-0.26; P < .01), and between the triple-negative subtype and the other subtypes (HR = 5.48; 95% CI, 1.88-16.0; P < .01) groups.Discontinuation of whole-brain radiotherapy and the presence of triple-negative breast cancer were indicators of poor prognosis.


Assuntos
Neoplasias Encefálicas/secundário , Carcinomatose Meníngea/secundário , Neoplasias de Mama Triplo Negativas/mortalidade , Idoso , Biomarcadores Tumorais , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/radioterapia , Relação Dose-Resposta à Radiação , Feminino , Humanos , Imagem por Ressonância Magnética , Carcinomatose Meníngea/diagnóstico por imagem , Carcinomatose Meníngea/radioterapia , Pessoa de Meia-Idade , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Neoplasias de Mama Triplo Negativas/patologia
6.
PLoS One ; 15(8): e0231510, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32818954

RESUMO

With increasing medical radiation exposures, it is important to understand how different modes of delivery of ionizing radiation as well as total doses of exposure impact health outcomes. Our lab studied the risks associated with ionizing radiation by analyzing the Northwestern University Radiation Archive for animals (NURA). NURA contains detailed data from a series of 10 individual neutron and gamma irradiation experiments conducted on over 50,000 mice. Rigorous statistical testing on control mice from all Janus experiments enabled us to select studies that could be compared to one another and uncover unexpected differences among the controls as well as experimental animals. For controls, mice sham irradiated with 300 fractions died significantly earlier than those with fewer sham fractions and were excluded from the pooled dataset. Using the integrated dataset of gamma irradiated and control mice, we found that fractionation significantly decreased the death hazard for animals dying of lymphomas, tumors, non-tumors, and unknown causes. Gender differences in frequencies of causes of death were identified irrespective of irradiation and dose fractionation, with female mice being at a greater risk for all causes of death, except for lung tumors. Irradiated and control male mice were at a significantly greater risk for lung tumors, the opposite from observations noted in humans. Additionally, we discovered that lymphoma deaths can occur quickly after exposures to high doses of gamma rays. This study systematically cross-compared outcomes of different modes of fractionation evaluated across different Janus experiments and across a wide span of total doses. It demonstrates that protraction modulated survival and disease status differently based on the total dose, cause of death, and sex of an animal. This novel method for analyzing the Janus datasets will lead to insightful new mechanistic hypotheses and research in the fields of radiation biology and protection.


Assuntos
Relação Dose-Resposta à Radiação , Neoplasias/etiologia , Exposição à Radiação/efeitos adversos , Animais , Bases de Dados Factuais , Modelos Animais de Doenças , Fracionamento da Dose de Radiação , Feminino , Raios gama , Incidência , Masculino , Camundongos , Morbidade , Nêutrons , Exposição à Radiação/estatística & dados numéricos , Radiação Ionizante , Eficiência Biológica Relativa
8.
Photochem Photobiol ; 96(5): 1083-1087, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32767758

RESUMO

The COVID-19 pandemic has resulted in an international shortage of personal protective equipment including N95 filtering facepiece respirators (FFRs), resulting in many institutions using ultraviolet germicidal irradiation (UVGI) technology for N95 FFR decontamination. To ensure proper decontamination, it is crucial to determine the dose received by various parts of the FFR in this process. Recently, our group customized a UVGI unit for N95 decontamination. With experimental and theoretical approach, this manuscript discusses the minimum dose received by various parts of the N95 respirator after one complete decontamination cycle with this UVGI unit. The results demonstrate that all parts of the N95 FFR received at least 1 J cm-2 after one complete decontamination cycle with this unit. As there are a variety of UVGI devices and different types of FFRs, this study provides a model by which UVC dose received by different areas of the FFRs can be accurately assessed to ensure proper decontamination for the safety of healthcare providers.


Assuntos
Betacoronavirus/patogenicidade , Infecções por Coronavirus/prevenção & controle , Descontaminação/métodos , Desinfecção/métodos , Pandemias/prevenção & controle , Equipamento de Proteção Individual/virologia , Pneumonia Viral/prevenção & controle , Betacoronavirus/fisiologia , Infecções por Coronavirus/transmissão , Infecções por Coronavirus/virologia , Relação Dose-Resposta à Radiação , Humanos , Pneumonia Viral/transmissão , Pneumonia Viral/virologia , Radiometria/estatística & dados numéricos , Raios Ultravioleta
9.
Int J Nanomedicine ; 15: 3669-3680, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32547021

RESUMO

Introduction: The exhaustion and poor homing of activated lymphocytes are critical obstacles in adoptive cell immunotherapy for solid tumors. In order to effectively deliver immune cells into tumors, we encapsulated interferon-α2b (IFN-α2b) into macroporous hydrogels as an enhancement factor and utilized low-dose irradiation (LDI) as a tumoral attractor of T cells. Methods: Hydroxypropyl cellulose hydrogels were prepared by irradiation techniques, and the cross-sectional microstructure was characterized by scanning electron microscopy. The synergistic antitumor mechanism of combination of IFN-α2b and CIK cells was evaluated by detecting the expression of activation marker CD69 on CIK cell surface and IFN-γ production by CIK cells. The in vivo antitumor activity of IFN-α2b-incorporated hydroxypropyl cellulose hydrogels combined with CIK and radiation was evaluated in an MKN-45 xenografted nude mice model. Results: The bioactivity of IFN-α2b was well maintained in ultraviolet-reactive, rapidly cross-linkable hydroxypropyl cellulose hydrogels. In vitro studies demonstrated IFN-α2b-activated T cells, as evidenced by upregulating early activation marker CD69 and secretion inflammatory cytokine IFN-γ. In vivo real-time image showed our hydrogels kept a higher amount of drug delivery at the tumor site for a long time compared with free drug injection. Low-dose irradiation promoted T cell accumulation and infiltration in subcutaneous tumors. Combination of IFN-α2b-loaded hydrogels (Gel-IFN) with T cells and LDI exhibited higher efficacy to eradicate human gastric cancer xenograted tumors with less proliferating cells and more necrotic regions compared with IFN-α2b or T cells alone. Discussion: HPC hydrogels kept the activity of IFN-α2b and stably release of IFN-α2b to stimulate T cells for a long time. At the same time, low-dose radiation recruits T cells into tumors. This innovative integration mode of IFN-α2b-loaded hydrogels and radiotherapy offers a potent strategy to improve the therapeutic outcome of T cell therapy.


Assuntos
Antineoplásicos/uso terapêutico , Reagentes para Ligações Cruzadas/química , Hidrogéis/química , Interferon-alfa/uso terapêutico , Luz , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/radioterapia , Linfócitos T/imunologia , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Celulose/análogos & derivados , Celulose/química , Relação Dose-Resposta à Radiação , Elétrons , Humanos , Interferon-alfa/farmacologia , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Linfócitos T/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
10.
Int J Nanomedicine ; 15: 3719-3727, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32547024

RESUMO

Purpose: Most solid tumors contain areas of chronic hypoxia. Gold nanoparticles (GNP) have been extensively explored as enhancers of external beam radiation; however, GNP have lower cellular uptake in hypoxic conditions than under normoxic conditions. Conversely, the chelator diacetyl-bis (N(4)-methylthiosemicarbazonato) copper II (CuATSM) deposits copper in hypoxic regions, allowing for dose enhancement in previously inaccessible regions. Methods: External beam sources with different spectra were modeled using a Monte Carlo code (EGSnrc) to evaluate radioenhancement in a layered model with metal solutions. Also considered was a simple concentric layered tumor model containing a hypoxic core with each layer varying in concentrations of either copper or gold according to hypoxic conditions. Low energy external photon beams were then projected onto the tumor to determine the regional dose enhancement dependent on hypoxic conditions. Results: Dose enhancement was more pronounced for beam spectra with low energy photons (225 kVp) and was highly dependent on metal concentrations from 0.1 g/kg to 100 g/kg. Increasing the depth of the metallic solution layer from 1 cm to 6 cm decreased dose enhancement. A small increase in the dose enhancement factor (DEF) of 1.01 was predicted in the hypoxic regions of the tumor model with commonly used diagnostic concentrations of CuATSM. At threshold concentrations of toxic subcutaneous injection levels, the DEF increases to 1.02, and in simulation of a high concentration of CuATSM, the DEF increased to 1.07. High concentration treatments are also considered, as well as synergistic combinations of GNP/CuATSM treatments. Conclusion: The research presented is novel utilization of CuATSM to target hypoxic regions and act as a radiosensitizer by the nature of its ability to deposit copper metal in reduced tissue. We demonstrate CuATSM at high concentrations with low energy photons can increase dose deposition in hypoxic tumor regions.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Método de Monte Carlo , Compostos Organometálicos/farmacocinética , Fótons , Tiossemicarbazonas/farmacocinética , Hipóxia Tumoral , Relação Dose-Resposta à Radiação , Modelos Biológicos , Imagens de Fantasmas , Radiossensibilizantes/farmacologia , Hipóxia Tumoral/efeitos dos fármacos , Hipóxia Tumoral/efeitos da radiação
11.
Int J Food Microbiol ; 330: 108695, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-32502761

RESUMO

Norovirus (NoV) is the leading cause of epidemic and sporadic gastroenteritis worldwide; a high number of those cases are attributed to the consumption of contaminated food. Crop producers have used several strategies to inactivate the virus present in these products and thus stop the NoV transmission chain. Physical methods such as gamma radiation show excellent results in the inactivation of bacteria, but its effect on NoV has been little studied. This study aimed to evaluate the effect of gamma radiation for NoV inactivation, and over the surface topographic characteristics of strawberry cells, as a prototype of soft fruit. A 10% suspension of GII norovirus-positive stool samples were treated with either 200 mg/L of sodium hypochlorite (NaClO) or gamma-irradiated at doses of 5, 10, 15 and 20 kilograys (kGy). Viral inactivation was determined by measuring the integrity of viral capsid using RNase A alone or in combination with proteinase K followed by RT-qPCR. The effect over cellular surface topology characteristics of the fruit was measured by atomic force microscopy (AFM) and confocal microscopy. High doses of radiation (20 kGy) were necessary to detect a significant (p < 0.05) decrease of up to 1.26 log10 viral copy number. This dose significantly (p < 0.05) raises the root means square roughness (Rq), which affects directly the quality and texture of the product. The gamma irradiation doses tested in this study were not enough to inactivate NoV. The allowed gamma irradiation doses for fresh produce does not alter the surface topology of the fruit, but they affect the content of fluorescent compounds, responsible for the antioxidant activity of the fruit.


Assuntos
Fragaria/efeitos da radiação , Fragaria/virologia , Raios gama , Norovirus/efeitos da radiação , Inativação de Vírus/efeitos da radiação , Relação Dose-Resposta à Radiação , Microbiologia de Alimentos , Fragaria/efeitos dos fármacos , Frutas/efeitos dos fármacos , Frutas/efeitos da radiação , Frutas/virologia , Norovirus/fisiologia , Hipoclorito de Sódio/farmacologia , Inativação de Vírus/efeitos dos fármacos
12.
PLoS One ; 15(4): e0232597, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32353063

RESUMO

The use of low doses of radium-224 (224Ra) chloride for the treatment of ankylosing spondylitis was stopped following the discovery that patients treated with it had a higher than control incidence of leukaemia and other cancers. This was so even though the treatment resulted in decreased pain and increased mobility-both of which are associated with decreased mortality. It was decided to re-analyze the epidemiological data looking at all causes of death. The risk of leukaemia, solid cancer, death from non-cancer causes and from all causes in a study populations of men that received either the typical dose of 5.6 to 11.1 MBq of 224Ra, any dose of 224Ra or no radium were compared using the Cox proportional hazard model. For patients that received the typical dose of 224Ra agreed with the excess cancer was similar to that reported in previous studies. In contrast, these patients were less likely to die from non-cancer diseases and from all causes of death than the control patients. No excess mortality was also found in the population of all males that received the radionuclide. It is concluded that 224Ra treatment administered at low doses to patients with ankylosing spondylitis did not impact mortality from all causes. The study demonstrates the need to consider all causes of death and longevity when assessing health impacts following irradiation.


Assuntos
Causas de Morte , Leucemia/mortalidade , Neoplasias Induzidas por Radiação/mortalidade , Rádio (Elemento)/administração & dosagem , Retirada de Medicamento Baseada em Segurança , Espondilite Anquilosante/radioterapia , Tório/administração & dosagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Relação Dose-Resposta à Radiação , Seguimentos , Humanos , Injeções Intravenosas , Leucemia/etiologia , Masculino , Pessoa de Meia-Idade , Neoplasias Induzidas por Radiação/etiologia , Dosagem Radioterapêutica , Rádio (Elemento)/efeitos adversos , Espondilite Anquilosante/mortalidade , Tório/efeitos adversos , Fatores de Tempo
13.
PLoS One ; 15(5): e0233258, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32442228

RESUMO

The purpose of this paper is to characterize the skin deterministic damage due to the effect of proton beam irradiation in mice occurred during a long-term observational experiment. This study was initially defined to evaluate the insurgence of myelopathy irradiating spinal cords with the distal part of a Spread-out Bragg peak (SOBP). To the best of our knowledge, no study has been conducted highlighting high grades of skin injury at the dose used in this paper. Nevertheless these effects occurred. In this regard, the experimental evidence of significant insurgence of skin injury induced by protons using a SOBP configuration will be shown. Skin damages were classified into six scores (from 0 to 5) according to the severity of the injuries and correlated to ED50 (i.e. the radiation dose at which 50% of animals show a specific score) at 40 days post-irradiation (d.p.i.). The effects of radiation on the overall animal wellbeing have been also monitored and the severity of radiation-induced skin injuries was observed and quantified up to 40 d.p.i.


Assuntos
Terapia com Prótons/efeitos adversos , Lesões por Radiação/patologia , Pele/efeitos da radiação , Animais , Modelos Animais de Doenças , Relação Dose-Resposta à Radiação , Escala de Gravidade do Ferimento , Camundongos
14.
Br J Radiol ; 93(1112): 20190949, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32464080

RESUMO

OBJECTIVES: The relative biological effectiveness (RBE) of X-rays and γ radiation increases substantially with decreasing beam energy. This trend affects the efficacy of medical applications of this type of radiation. This study was designed to develop a model based on a survey of experimental data that can reliably predict this trend. METHODS: In our model, parameters α and ß of a cell survival curve are simple functions of the frequency-average linear energy transfer (LF) of delta electrons. The choice of these functions was guided by a microdosimetry-based model. We calculated LF by using an innovative algorithm in which LF is associated with only those electrons that reach a sensitive-to-radiation volume (SV) within the cell. We determined model parameters by fitting the model to 139 measured (α,ß) pairs. RESULTS: We tested nine versions of the model. The best agreement was achieved with [Formula: see text] and ß being linear functions of [Formula: see text] .The estimated SV diameter was 0.1-1 µm. We also found that α, ß, and the α/ß ratio increased with increasing [Formula: see text] . CONCLUSIONS: By combining an innovative method for calculating [Formula: see text] with a microdosimetric model, we developed a model that is consistent with extensive experimental data involving photon energies from 0.27 keV to 1.25 MeV. ADVANCES IN KNOWLEDGE: We have developed a photon RBE model applicable to an energy range from ultra-soft X-rays to megaelectron volt γ radiation, including high-dose levels where the RBE cannot be calculated as the ratio of α values. In this model, the ionization density represented by [Formula: see text] determines the RBE for a given photon spectrum.


Assuntos
Sobrevivência Celular/efeitos da radiação , Raios gama , Modelos Estatísticos , Raios X , Animais , Linhagem Celular , Cricetulus , Relação Dose-Resposta à Radiação , Fibroblastos/efeitos da radiação , Humanos , Camundongos , Doses de Radiação
15.
PLoS One ; 15(4): e0228350, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32320391

RESUMO

Dosimetry is an important tool for triage and treatment planning following any radiation exposure accident, and biological dosimetry, which estimates exposure dose using a biological parameter, is a practical means of determining the specific dose an individual receives. The cytokinesis-blocked micronucleus assay (CBMN) is an established biodosimetric tool to measure chromosomal damage in mitogen-stimulated human lymphocytes. The CBMN method is especially valuable for biodosimetry in triage situations thanks to simplicity in scoring and adaptability to high-throughput automated sample processing systems. While this technique produces dose-response data which fit very well to a linear-quadratic model for exposures to low linear energy transfer (LET) radiation and for doses up for 5 Gy, limitations to the accuracy of this method arise at larger doses. Accuracy at higher doses is limited by the number of cells reaching mitosis. Whereas it would be expected that the yield of micronuclei increases with the dose, in many experiments it has been shown to actually decrease when normalized over the total number of cells. This variation from a monotonically increasing dose response poses a limitation for retrospective dose reconstruction. In this study we modified the standard CBMN assay to increase its accuracy following exposures to higher doses of photons or a mixed neutron-photon beam. The assay is modified either through inhibitions of the G2/M and spindle checkpoints with the addition of caffeine and/or ZM447439 (an Aurora kinase inhibitor), respectively to the blood cultures at select times during the assay. Our results showed that caffeine addition improved assay performance for photon up to 10 Gy. This was achieved by extending the assay time from the typical 70 h to just 74 h. Compared to micronuclei yields without inhibitors, addition of caffeine and ZM447439 resulted in improved accuracy in the detection of micronuclei yields up to 10 Gy from photons and 4 Gy of mixed neutrons-photons. When the dose-effect curves were fitted to take into account the turnover phenomenon observed at higher doses, best fitting was achieved when the combination of both inhibitors was used. These techniques permit reliable dose reconstruction after high doses of radiation with a method that can be adapted to high-throughput automated sample processing systems.


Assuntos
Citogenética , Doses de Radiação , Radiometria , Adulto , Benzamidas/farmacologia , Cafeína/farmacologia , Células Cultivadas , Relação Dose-Resposta à Radiação , Feminino , Humanos , Linfócitos/efeitos dos fármacos , Linfócitos/efeitos da radiação , Masculino , Testes para Micronúcleos , Pessoa de Meia-Idade , Nêutrons , Prótons , Quinazolinas/farmacologia
16.
Ecotoxicol Environ Saf ; 196: 110489, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32278137

RESUMO

Sedentary shallow water marine organisms acquire numerous protective mechanisms to mitigate the detrimental effects of UV radiation (UV-R). Here we investigated morphological and gene expression outcomes in colonies of the cosmopolitan ascidian Botryllus schlosseri, up to 15-days post UV-B irradiation. Astogeny in Botryllus is characterized by weekly repeating sets of asexual budding, coinciding with apoptotic elimination of functional zooids (blastogenesis). Ten UV-B doses were administered to three clusters: sublethal, enhanced-mortality, lethal (LD50 = 6.048 kJ/m2) which differed in mortality rates, yet reflected similar distorted morphotypes, and arrested blastogenesis, all intensified in the enhanced-mortality/lethal clusters. Even the sub-lethal doses inflicted expression modifications in 8 stress proteins (HSP 90/70 families and NIMA) as well as morphological blastogenesis. The morphological/gene-expression impacts in surviving colonies lasted for 15 days post irradiation (two blastogenic-cycles), where all damaged and arrested zooids/buds were absorbed, after which the colonies returned to their normal blastogenic-cycles and gene expression profiles, and initiated new buds. The above reflects a novel colonial maintenance strategy associated with the disposable-soma tenet, where the ephemeral soma in Botryllus is eliminated without engaging with the costs of repair, whereas other colonial components, primarily the pool of totipotent stem cells, are sustained under yet unknown colonial-level regulatory cues.


Assuntos
Raios Ultravioleta/efeitos adversos , Urocordados/fisiologia , Urocordados/efeitos da radiação , Animais , Organismos Aquáticos/fisiologia , Organismos Aquáticos/efeitos da radiação , Relação Dose-Resposta à Radiação , Proteínas de Choque Térmico/genética , Reprodução Assexuada/efeitos da radiação , Transcriptoma/efeitos da radiação
17.
Radiology ; 295(3): 664-674, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32255418

RESUMO

Background MRI performed at 3.0 T offers greater signal-to-noise ratio and better spatial resolution than does MRI performed at 1.5 T; however, for fetal MRI, there are concerns about the potential for greater radiofrequency energy administered to the fetus at 3.0-T MRI. Purpose To compare the specific absorption rate (SAR) and specific energy dose (SED) of fetal MRI at 1.5 and 3.0 T. Materials and Methods In this retrospective study, all fetal MRI examinations performed with 1.5- and 3.0-T scanners at one institution between July 2012 and October 2016 were evaluated. Two-dimensional (2D) and three-dimensional (3D) steady-state free precession (SSFP), single-shot fast spin-echo, 2D and 3D T1-weighted spoiled gradient-echo (SPGR), and echo-planar imaging sequences were performed. SAR, SED, accumulated SED, and acquisition time were retrieved from the Digital Imaging and Communications in Medicine header. Data are presented as mean ± standard deviation. Two one-sided tests with equivalence bounds of 0.5 (Cohen d effect size) were performed, with statistical equivalence considered at P < .05. Results A total of 2952 pregnant women were evaluated. Mean maternal age was 30 years ± 6 (age range, 12-49 years), mean gestational age was 24 weeks ± 6 (range, 17-40 weeks). A total of 3247 fetal MRI scans were included, with 2784 (86%) obtained at 1.5 T and 463 (14%) obtained at 3.0 T. In total, 93 764 sequences were performed, with 81 535 (87%) performed at 1.5 T and 12 229 (13%) performed at 3.0 T. When comparing 1.5- with 3.0-T MRI sequences, mean SAR (1.09 W/kg ± 0.69 vs 1.14 W/kg ± 0.61), mean SED (33 J/kg ± 27 vs 38 J/kg ± 26), and mean accumulated SED (965 J/kg ± 408 vs 996 J/kg ± 366, P < .001) were equivalent. Conclusion Fetal 1.5- and 3.0-T MRI examinations were found to have equivalent energy metrics in most cases. The 3.0-T sequences, such as two-dimensional T1-weighted spoiled gradient-echo and three-dimensional steady-state free precession, may require modification to keep the energy delivered to the patient as low as possible. © RSNA, 2020 Online supplemental material is available for this article.


Assuntos
Feto/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Diagnóstico Pré-Natal/métodos , Adolescente , Adulto , Criança , Relação Dose-Resposta à Radiação , Feminino , Idade Gestacional , Humanos , Aumento da Imagem , Masculino , Pessoa de Meia-Idade , Gravidez , Razão Sinal-Ruído , Adulto Jovem
18.
Radiat Res ; 193(6): 543-551, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32282289

RESUMO

In the event of a mass casualty radiation scenario, rapid assessment of patients' health and triage is required for optimal resource utilization. Identifying the level and extent of exposure as well as prioritization of care is extremely challenging under such disaster conditions. Blood-based biomarkers, such as RNA integrity numbers (RIN), could help healthcare personnel quickly and efficiently determine the extent and effect of multiple injuries on patients' health. Evaluation of the effect of different radiation doses, alone or in combination with burn injury, on total RNA integrity over multiple time points was performed. Total RNA integrity was tallied in blood samples for potential application as a marker of radiation exposure and survival. Groups of aged mice (3-6 mice/group, 13-18 months old) received 0.5, 1, 5, 10 or 20 Gy ionizing radiation. Two additional mouse groups received low-dose irradiation (0.5 or 1 Gy) with a 15% total body surface area (TBSA) burn injury. Animals were euthanized at 2 or 12 h and at day 1, 2, 3, 7 or 14 postirradiation, or when injury-mediated mortality occurred. Total RNA was isolated from blood. The quality of RNA was evaluated and RNA RIN were obtained. Analysis of RIN indicated that blood showed the clearest radiation effect. There was a time- and radiation-dose-dependent reduction in RIN that was first detectable at 12 h postirradiation for all doses in animals receiving irradiation alone. This effect was reversible in lower-dose groups (i.e., 0.5, 1 and 5 Gy) that survived to the end of the study (14 days). In contrast, the effect persisted for 10 and 20 Gy groups, which showed suppression of RIN values <4.5 with high mortalities. Radiation doses of 20 Gy were lethal and required euthanasia by day 6. A low RIN (<2.5) at any time point was associated with 100% mortality. Combined radiation-burn injury produced significantly increased mortality such that no dually-injured animals survived beyond day 3, and no radiation dose >1 Gy resulted in survival past day 1. More modest suppression of RIN was observed in the surviving dually challenged mice, and no statistically significant changes were identified in RIN values of burn-only mice at any time point. In this study of an animal model, a proof of concept is presented for a simple and accurate method of assessing radiation dose exposure in blood which potentially predicts lethality. RIN assessment of blood-derived RNA could form the basis for a clinical decision-support tool to guide healthcare providers under the strenuous conditions of a radiation-based mass casualty event.


Assuntos
RNA/sangue , Exposição à Radiação , Animais , Biomarcadores/sangue , Relação Dose-Resposta à Radiação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Projetos Piloto
19.
Zhonghua Zhong Liu Za Zhi ; 42(2): 139-144, 2020 Feb 23.
Artigo em Chinês | MEDLINE | ID: mdl-32135649

RESUMO

Objective: To evaluate the prognostic factors of T1-2N0M0 esophageal squamous cell carcinoma (ESCC) treated with definitive radiotherapy. Methods: The clinical data of 196 patients with T1-2N0M0 ESCC who were treated with definitive radiotherapy in 10 hospitals were retrospectively analyzed. All sites were members of Jing-Jin-Ji Esophageal and Esophagogastric Cancer Radiotherapy Oncology Group (3JECROG). Radiochemotherapy were applied to 78 patients, while the other 118 patients received radiotherapy only. 96 patients were treated with three-dimensional conformal radiotherapy (3DCRT) and 100 treated with intensity-modulated radiotherapy (IMRT). The median dose of plan target volume(PTV) and gross target volume(GTV) were both 60 Gy. The median follow-up time was 59.2 months. Log rank test and Cox regression analysis were used for univariat and multivariate analysis, respectively. Results: The percentage of normal lung receiving at least 20 Gy (V(20)) was (18.65±7.20)%, with average dose of (10.81±42.05) Gy. The percentage of normal heart receiving at least 30 Gy (V(30)) was (14.21±12.28)%. The maximum dose of exposure in spinal cord was (39.65±8.13) Gy. The incidence of radiation pneumonia and radiation esophagitis were 14.80%(29/196) and 65.82%(129/196), respectively. The adverse events were mostly grade 1-2, without grade 4 toxicity. Median overall survival (OS) and progression-free survival (PFS) were 70.1 months and 62.3 months, respectively. The 1-, 3- and 5-year OS rates of all patients were 75.1%、57.4% and 53.2%, respectively. The 1-, 3- and 5-year PFS rates were 75.1%、57.4% and 53.2%, respectively. Multivariate analysis demonstrated that patients'age (HR=1.023, P=0.038) and tumor diameter (HR=1.243, P=0.028)were the independent prognostic factors for OS, while tumor volume were the independent prognostic factor for PFS. Conclusions: Definitive radiotherapy is a promising therapeutic method in patients with T1-2N0M0 ESCC. Patients' age, tumor diameter and tumor volume may impact patients' prognosis.


Assuntos
Neoplasias Esofágicas/radioterapia , Carcinoma de Células Escamosas do Esôfago/radioterapia , Antineoplásicos/uso terapêutico , Quimiorradioterapia , Relação Dose-Resposta à Radiação , Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/patologia , Carcinoma de Células Escamosas do Esôfago/tratamento farmacológico , Carcinoma de Células Escamosas do Esôfago/mortalidade , Carcinoma de Células Escamosas do Esôfago/patologia , Humanos , Prognóstico , Dosagem Radioterapêutica , Radioterapia Conformacional , Radioterapia de Intensidade Modulada , Estudos Retrospectivos
20.
PLoS One ; 15(3): e0230812, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32214399

RESUMO

The aim of this study was to assess the efficacy of lactic acid (LA), caprylic acid (CA), high- (HDI) and low- (LDI) dose gamma irradiation and LDI combined with LA or CA on the inactivation of a pool of Shiga toxin-producing Escherichia coli (STEC) strains inoculated on beef trimmings. The three most efficacious treatments were selected to study their effect on meat quality parameters and sensory attributes. The inoculum included five native STEC serogroups (O26, O103, O111, O145 and O157). The treatments applied were 0.5% LA, 0.04% CA, 0.5 kGy LDI, 2 kGy HDI, LDI+LA and LDI+CA. Beef trimmings were divided into two groups; one was inoculated with high (7 log CFU/g) and the other with low (1 log CFU/g) level of inoculum. Efficacy was assessed by estimating log reduction and reduction of stx- and eae-positive samples after enrichment, respectively. Results showed that treatments with organic acids alone were not effective in reducing STEC populations. For high inoculum samples, the most effective treatment was HDI followed by LDI+LA and LDI alone or combined with CA. For low inoculum samples, the most effective treatment was HDI followed by LDI alone or combined with organic acids. Concerning meat quality parameters and sensory attributes, irradiation treatments (LDI and HDI) caused minimal changes, while LDI+LA modified them significantly compared with the control. Therefore, based on our results, no benefits were observed after combining organic acids with gamma irradiation.


Assuntos
Caprilatos/farmacologia , Raios gama , Ácido Láctico/farmacologia , Carne Vermelha/microbiologia , Escherichia coli Shiga Toxigênica/efeitos dos fármacos , Escherichia coli Shiga Toxigênica/efeitos da radiação , Relação Dose-Resposta à Radiação , Qualidade dos Alimentos , Inocuidade dos Alimentos , Concentração de Íons de Hidrogênio , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos da radiação , Viabilidade Microbiana/efeitos dos fármacos , Viabilidade Microbiana/efeitos da radiação , Oxirredução/efeitos dos fármacos , Oxirredução/efeitos da radiação , Escherichia coli Shiga Toxigênica/fisiologia , Paladar
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