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1.
An Acad Bras Cienc ; 93(2): e20190249, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33950149

RESUMO

Anastrepha fraterculus (Wiedemann, 1830) (Diptera: Tephritidae) is a major fruit pest, which is basicaly controlled using insecticides, which represents a risk to beneficial arthropods, human health and food contamination. The sterile insect technique (SIT) is a potential alternative tool for the management of this pest, however, only conflicting data is found regarding the optimal dose to achieve sterility. Thus, this study evaluated the effect of gamma radiation doses (0, 40, 50, 60 and 70 Gy) on male and female reproductive sterility, gonads morphometry, emergence, flight ability, and longevity under nutritional stress of A. fraterculus. Full female sterility was achieved at 50 Gy, while full male sterility was achieved at 70 Gy. Both ovarian and testicular sizes were affected by irradiation, while no influence was observed on the quality parameters evaluated. Our results suggest that 70 Gy applied 48 h before adult emergence can be used to sterilize A. fraterculus in a SIT programme.


Assuntos
Infertilidade , Tephritidae , Animais , Feminino , Raios gama , Humanos , Longevidade , Masculino , Controle Biológico de Vetores
2.
PLoS One ; 16(4): e0248859, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33831014

RESUMO

In response to personal protective equipment (PPE) shortages in the United States due to the Coronavirus Disease 2019, two models of N95 respirators were evaluated for reuse after gamma radiation sterilization. Gamma sterilization is attractive for PPE reuse because it can sterilize large quantities of material through hermetically sealed packaging, providing safety and logistic benefits. The Gamma Irradiation Facility at Sandia National Laboratories was used to irradiate N95 filtering facepiece respirators to a sterilization dose of 25 kGy(tissue). Aerosol particle filtration performance testing and electrostatic field measurements were used to determine the efficacy of the respirators after irradiation. Both respirator models exhibited statistically significant decreases in particle filtering efficiencies and electrostatic potential after irradiation. The largest decrease in capture efficiency was 40-50% and peaked near the 200 nm particle size. The key contribution of this effort is correlating the electrostatic potential change of individual filtration layer of the respirator with the decrease filtration efficiency after irradiation. This observation occurred in both variations of N95 respirator that we tested. Electrostatic potential measurement of the filtration layer is a key indicator for predicting filtration efficiency loss.


Assuntos
/prevenção & controle , Raios gama , Esterilização , Inativação de Vírus/efeitos da radiação , /transmissão , Humanos , Estados Unidos
3.
Sci Rep ; 11(1): 5804, 2021 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-33707532

RESUMO

COVID-19 outbreak caused by SARS-CoV-2 created an unprecedented health crisis since there is no vaccine for this novel virus. Therefore, SARS-CoV-2 vaccines have become crucial for reducing morbidity and mortality. In this study, in vitro and in vivo safety and efficacy analyzes of lyophilized vaccine candidates inactivated by gamma-irradiation were performed. The candidate vaccines in this study were OZG-3861 version 1 (V1), an inactivated SARS-CoV-2 virus vaccine, and SK-01 version 1 (V1), a GM-CSF adjuvant added vaccine. The candidate vaccines were applied intradermally to BALB/c mice to assess toxicity and immunogenicity. Preliminary results in vaccinated mice are reported in this study. Especially, the vaccine models containing GM-CSF caused significant antibody production with neutralization capacity in absence of the antibody-dependent enhancement feature, when considered in terms of T and B cell responses. Another important finding was that the presence of adjuvant was more important in T cell in comparison with B cell response. Vaccinated mice showed T cell response upon restimulation with whole inactivated SARS-CoV-2 or peptide pool. This study shows that the vaccines are effective and leads us to start the challenge test to investigate the gamma-irradiated inactivated vaccine candidates for infective SARS-CoV-2 virus in humanized ACE2 + mice.


Assuntos
/imunologia , Imunogenicidade da Vacina , Vacinas de Produtos Inativados/imunologia , Animais , Feminino , Raios gama , Genoma Viral , Humanos , Masculino , Camundongos Endogâmicos BALB C , Vacinas de Produtos Inativados/toxicidade
4.
Int J Mol Sci ; 22(5)2021 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-33673647

RESUMO

Small RNAs are essential to coordinate many cellular processes, including the regulation of gene expression patterns, the prevention of genomic instability, and the suppression of the mutagenic transposon activity. These processes determine the aging, longevity, and sensitivity of cells and an organism to stress factors (particularly, ionizing radiation). The biogenesis and activity of small RNAs are provided by proteins of the Argonaute family. These proteins participate in the processing of small RNA precursors and the formation of an RNA-induced silencing complex. However, the role of Argonaute proteins in regulating lifespan and radioresistance remains poorly explored. We studied the effect of knockdown of Argonaute genes (AGO1, AGO2, AGO3, piwi) in various tissues on the Drosophila melanogaster lifespan and survival after the γ-irradiation at a dose of 700 Gy. In most cases, these parameters are reduced or did not change significantly in flies with tissue-specific RNA interference. Surprisingly, piwi knockdown in both the fat body and the nervous system causes a lifespan increase. But changes in radioresistance depend on the tissue in which the gene was knocked out. In addition, analysis of changes in retrotransposon levels and expression of stress response genes allow us to determine associated molecular mechanisms.


Assuntos
Proteínas Argonauta/antagonistas & inibidores , Proteínas de Drosophila/antagonistas & inibidores , Drosophila melanogaster/crescimento & desenvolvimento , Longevidade/genética , RNA Interferente Pequeno/genética , Tolerância a Radiação/genética , Animais , Proteínas Argonauta/genética , Proteínas Argonauta/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/efeitos da radiação , Feminino , Raios gama , Masculino , Especificidade de Órgãos , Interferência de RNA
5.
Life Sci ; 275: 119388, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33774028

RESUMO

Radiation-induced multiple organ injury, including γ-radiation nephropathy, is the most common. Even with dose fractionation strategy, residual late side effects are inevitable. Bone marrow-derived mesenchymal stem cells (BM-MSCs) transplantation and erythropoietin (EPO) have shown to be effective in treating chronic kidney disease and associated anemia. This study aimed to evaluate the effect of BM-MSCs and/or EPO in fractionated γ-irradiation induced kidney damage in rats. Adult male Wistar rats were randomized into 2 groups; normal and 8 Gy (fractionated dose of 2 Gy for 4 days) γ-irradiated rats. Animal from both groups were subdivided to receive the following treatments: BM-MSCs (1 × 106 cells/rat, i.v - once), EPO (100 IU/kg, i.p - every other day for 30 days) or their combined treatment (BM-MSCs and EPO). γ-Irradiated rats showed a noticeable elevation in serum urea and creatinine, kidney malondialdehyde (MDA) and caspase 3 activity. They also revealed significant drop in kidney glutathione (GSH) and Bcl2 protein contents. Conspicuously, they revealed down-regulation of renal EPO signaling (EPO, EPOR, pJAK2, pPI3K and pAkt). Conversely, groups treated with BM-MSCs and/or EPO revealed significant modulation in most tested parameters and appeared to be effective in minimizing the hazard effects of radiation. In conclusion, BM-MSCs and/or EPO exhibited therapeutic potentials against nephrotoxicity induced by fractionated dose of γ-irradiation. An effect mediated by antioxidant and non-hematopoietic EPO downstream anti-apoptotic signaling (PI3K/Akt) pathway. EPO potentiate the repair capabilities of BM-MSCs making this combined treatment a promising therapeutic strategy to overcome radiotherapy-induced kidney damage.


Assuntos
Apoptose , Eritropoetina/uso terapêutico , Rim/efeitos da radiação , Transplante de Células-Tronco Mesenquimais , Lesões Experimentais por Radiação/terapia , Animais , Apoptose/efeitos dos fármacos , Terapia Combinada , Creatinina/sangue , Raios gama/efeitos adversos , Masculino , Ratos , Ratos Wistar , Ureia/sangue
6.
Life Sci ; 276: 119429, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33785333

RESUMO

AIM: The therapeutic expediency of cisplatin was limited due to its nephrotoxic side effects, so this study planned to assess the nephrotic and neuroprotective impact of metformin (MET) and low-dose radiation (LDR) in cisplatin-prompted kidney injury and uremic encephalopathy (UE). METHODS: The effect of the 10-day MET treatment (200 mg/kg, orally) and/or fractionated LDR (0.25 Gy, of the total dose of 0.5 Gy, 1st and 7th day, respectively) on (5 mg/kg, intraperitoneally) cisplatin as a single dose was administered at the 5th day. Serum urea, creatinine and renal kidney injury molecule-1 were measured for the assessment of kidney function. Furthermore, the antioxidant potential in the renal and brain tissues was evaluated through, malondialdehyde and reduced glutathione estimation. Moreover, renal apoptotic markers: AMP-activated protein kinase, lipocalin, B-cell lymphoma 2 associated X protein, B-cell lymphoma 2, P53 and beclin 1 were estimated. UE was evaluated through the determination of serum inflammatory markers: nuclear factor kappa B, tumor-necrosis factor-α and interleukin 1 beta likewise, the cognitive deficits were assessed via forced swimming test, gamma-aminobutyric acid, n-methyl-d-aspartate and neuronal nitric oxide synthases besides AMP-activated protein kinase, light chain 3 and caspase3 levels in rats' cerebella. KEY FINDINGS: The obtained results revealed a noticeable improvement in the previously mentioned biochemical factors and behavioral tasks that was reinforced by histopathological examination when using the present remedy. SIGNIFICANCE: metformin and low doses of radiation afforded renoprotection and neuroprotection against cisplatin-induced acute uremic encephalopathy.


Assuntos
Biomarcadores/metabolismo , Encefalopatias/prevenção & controle , Cisplatino/toxicidade , Raios gama , Metformina/farmacologia , Fármacos Neuroprotetores/farmacologia , Uremia/prevenção & controle , Animais , Antineoplásicos/toxicidade , Encefalopatias/induzido quimicamente , Encefalopatias/metabolismo , Encefalopatias/patologia , Relação Dose-Resposta à Radiação , Glutationa/metabolismo , Hipoglicemiantes/farmacologia , Masculino , NF-kappa B/metabolismo , Estresse Oxidativo , Ratos , Fator de Necrose Tumoral alfa/metabolismo , Uremia/induzido quimicamente , Uremia/metabolismo , Uremia/patologia
7.
Int J Mol Sci ; 22(4)2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33673196

RESUMO

Intestinal injury is observed in cancer patients after radiotherapy and in individuals exposed to radiation after a nuclear accident. Radiation disrupts normal vascular homeostasis in the gastrointestinal system by inducing endothelial damage and senescence. Despite advances in medical technology, the toxicity of radiation to healthy tissue remains an issue. To address this issue, we investigated the effect of atorvastatin, a commonly prescribed hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor of cholesterol synthesis, on radiation-induced enteropathy and inflammatory responses. We selected atorvastatin based on its pleiotropic anti-fibrotic and anti-inflammatory effects. We found that atorvastatin mitigated radiation-induced endothelial damage by regulating plasminogen activator inhibitor-1 (PAI-1) using human umbilical vein endothelial cells (HUVECs) and mouse model. PAI-1 secreted by HUVECs contributed to endothelial dysfunction and trans-endothelial monocyte migration after radiation exposure. We observed that PAI-1 production and secretion was inhibited by atorvastatin in irradiated HUVECs and radiation-induced enteropathy mouse model. More specifically, atorvastatin inhibited PAI-1 production following radiation through the JNK/c-Jun signaling pathway. Together, our findings suggest that atorvastatin alleviates radiation-induced enteropathy and supports the investigation of atorvastatin as a radio-mitigator in patients receiving radiotherapy.


Assuntos
Atorvastatina/farmacologia , Raios gama/efeitos adversos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Enteropatias/metabolismo , Monócitos/metabolismo , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Lesões Experimentais por Radiação/metabolismo , Migração Transendotelial e Transepitelial , Animais , Células Endoteliais da Veia Umbilical Humana/patologia , Humanos , Enteropatias/patologia , Camundongos , Monócitos/patologia , Lesões Experimentais por Radiação/patologia , Migração Transendotelial e Transepitelial/efeitos dos fármacos , Migração Transendotelial e Transepitelial/efeitos da radiação
8.
Mutat Res ; 863-864: 503312, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33678244

RESUMO

Most blood components for transfusions are irradiated ex vivo to prevent transfusion-associated graft-versus-host disease (TA-GvHD); this irradiation can potentially affect the cytogenetic dose assessment of patients showing acute radiation syndrome (ARS) with bone marrow suppression or acute anaemia. Whole blood samples from five donors were irradiated with 0, 10 or 25 Gy γ-rays. The mitotic activity of each cultured blood sample was measured by calculating the mitotic index. A dicentric chromosome assay was used to evaluate the chromosomal aberrations and absorbed dose of blood lymphocytes. Mitogenic activity and scorable metaphase spreads were significantly decreased in the blood samples irradiated with 10 and 25 Gy (p < 0.001). Moreover, a significant increase in the mean scores of all types of chromosomal aberrations in the 10 Gy γ-irradiated samples was observed, with the estimated dose being 11.3 Gy (95% CI: 10.67-11.95 Gy); however, we were unable to estimate the exposure dose in the 25 Gy γ-irradiated samples due to a limited number of scorable metaphase spreads. The mitotic index of the 25 Gy γ-irradiated whole blood samples was significantly suppressed by more than 4-log fold. Thus, in the present study, we evaluated the effects of recommended radiation doses in γ-irradiated transplantation blood components using cytogenetic dosimetry. These results suggest that the partial transfusion of blood components to patients with ARS or acute anaemia did not compromise the estimation of the exposure dose using cytogenetic dosimetry.


Assuntos
Aberrações Cromossômicas/efeitos da radiação , Raios gama/efeitos adversos , Linfócitos/metabolismo , Adulto , Relação Dose-Resposta à Radiação , Feminino , Humanos , Linfócitos/patologia , Masculino , Doses de Radiação
9.
Mutat Res ; 863-864: 503321, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33678246

RESUMO

Previous studies showed that the yield of cobalt-60 γ-rays-induced nucleoplasmic bridges (NPB) in human peripheral blood lymphocytes is dose dependent. However, the influence of the radiation quality and dose rates on NPB frequencies has not been investigated. The present study aimed to investigate NPB frequencies in human peripheral blood lymphocytes induced by carbon ions and explore the dose rate effect on cobalt-60 γ-rays-induced NPB. To establish dose-response curves, human peripheral blood samples were irradiated with 0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 and 8.0 Gy of carbon ions at a dose rate of 3.0 Gy/min in vitro. To explore the dose rate effect, human peripheral blood samples were irradiated with 2.0 and 5.0 Gy of cobalt-60 γ-rays at dose rates of 0.2, 0.5, 1.0, 3.0, 5.0 and 10.0 Gy/min in vitro. NPB and micronuclei (MN) in binucleated cells were analyzed with the cytokinesis-block micronucleus cytome assay. Results showed that the dose-response curve of carbon ion-induced NPB frequencies follow a linear-quadratic model (R2 = 0.934). The relative biological effectiveness (RBE) values of carbon ions to cobalt-60 γ-rays decreased with increased NPB frequencies (ranging from 2.47 to 5.86). Compared with group 1.0 Gy/min, the NPB frequencies in groups 10.0 Gy/min (2.0 Gy), 5.0 and 10.0 Gy/min (5.0 Gy) were decreased significantly (P < 0.05). Carbon ion-induced NPB in human peripheral blood lymphocytes have a good dose-response relationship. Cobalt-60 γ-rays-induced NPB frequencies are affected by the specific dose rate.


Assuntos
Radioisótopos de Cobalto , Dano ao DNA , Raios gama/efeitos adversos , Linfócitos/metabolismo , Adulto , Relação Dose-Resposta à Radiação , Humanos , Linfócitos/patologia , Masculino , Testes para Micronúcleos
10.
Food Chem ; 351: 129295, 2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-33631611

RESUMO

The knowledge of the changes in the lipid species in irradiated goat meat is expected to clarify the beneficial effects of irradiation on meat preservation. This study explored the characteristic lipid composition and the changes in irradiated goat meat based on quantitative lipidomics strategy by LC-MS. Totally, 12 subclasses of 174 lipids were identified with significant differences (p < 0.05, VIP > 1), and the absolute quantitative analysis of characteristic lipids was achieved. Significant lipid variables were involved in the major pathways of glycerophospholipid and sphingolipid metabolism. Moreover, significant increases during irradiation were found in total TG, PC, PE, LPE, Cer, LPC and SPH, while the total DG, PS, PG, PI and SM decreased after irradiation. Noteworthily, DHA-enriched PC (18:4/22:6) + H, a core nutrient for human health, exhibited an increase in the irradiated group. These results provide a basis for lipid quantitative alterations in irradiated goat meat and application of irradiation in meat preservation.


Assuntos
Raios gama , Lipidômica , Lipídeos/análise , Carne/análise , Animais , Cromatografia Líquida de Alta Pressão , Conservação de Alimentos , Cabras , Lipídeos/química , Espectrometria de Massas , Valor Nutritivo
11.
Mutat Res ; 861-862: 503276, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33551095

RESUMO

A radiation accident occurred in Bursa, Turkey, in July 2005. An industrial radiographer was exposed to industrial iridium-192 gamma rays for 5 h while laying the natural gas line. After 5 h, the victim had a break because of vomiting and nausea. He ended his work, considering that he might have been exposed to radiation. In a few days, erythema, pain, desquamation, edema started in both hands of the victim. The biological dose assessment was started based on frequencies of dicentrics and rings in peripheral blood lymphocytes ten days after the radiation accident. 6 repeated blood samples were taken for 9 years and analyzed staining after giemsa. After 9 years, decline at dicentric frequencies is significant, but still, dicentric contain cells were detected, which were a strong indicator for external radiation exposure.


Assuntos
Aberrações Cromossômicas/efeitos da radiação , Análise Citogenética/métodos , Raios gama/efeitos adversos , Linfócitos/patologia , Exposição à Radiação/efeitos adversos , Liberação Nociva de Radioativos/estatística & dados numéricos , Adulto , Seguimentos , Humanos , Linfócitos/efeitos da radiação , Masculino , Turquia
12.
Mutat Res ; 861-862: 503295, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33551098

RESUMO

Five occupational workers in an industrial sterilization unit at Stamboliyski in Bulgaria were accidentally exposed to a very high specific activity of Cobalt-60 source on June 14, 2011. Initial cytogenetic analysis performed on days 2 and 7 after radiation exposure revealed the whole body absorbed radiation doses of 5.32 Gy for patient 1, 3.40 Gy for patient 2, 2.50 Gy for patient 3, 1.91 Gy for patient 4 and 1.24 Gy for patient 5 [1]. Here, a retrospective multicolor FISH analysis was performed on three patients (patients 1, 2 and 3) using the blood samples collected over a period of 4 years from 2012 through 2015. In all the three patients, cells with stable chromosome aberrations (simple and complex chromosome translocations) were 3-4 folds more than cells with unstable chromosome aberrations (dicentric, rings and excess acentric chromosome fragments). In corroboration with the results reported in the literature, we observed that the time dependent decline of dicentrics, rings and excess acentric fragments occurred much more rapidly than chromosome translocations in the blood samples of the three victims. Further, inter-individual variation in the decline of radiation induced chromosome aberrations was also noticed among the three victims. The reason for the increased persistence of balanced chromosome translocations is not entirely clear but may be attributed to certain subsets of long-lived T-lymphocytes. The retrospective cytogenetic follow up studies on radiation-exposed victims may be useful for determining the extent of genomic/chromosomal instability in the hematopoietic system.


Assuntos
Aberrações Cromossômicas/efeitos da radiação , Análise Citogenética/métodos , Raios gama/efeitos adversos , Linfócitos/patologia , Exposição à Radiação/efeitos adversos , Liberação Nociva de Radioativos/estatística & dados numéricos , Adulto , Idoso , Feminino , Humanos , Linfócitos/efeitos da radiação , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos
13.
Lancet Oncol ; 22(3): 332-340, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33539729

RESUMO

BACKGROUND: The optimal radiotherapy dose for indolent non-Hodgkin lymphoma is uncertain. We aimed to compare 24 Gy in 12 fractions (representing the standard of care) with 4 Gy in two fractions (low-dose radiation). METHODS: FoRT (Follicular Radiotherapy Trial) is a randomised, multicentre, phase 3, non-inferiority trial at 43 study centres in the UK. We enrolled patients (aged >18 years) with indolent non-Hodgkin lymphoma who had histological confirmation of follicular lymphoma or marginal zone lymphoma requiring radical or palliative radiotherapy. No limit on performance status was stipulated, and previous chemotherapy or radiotherapy to another site was permitted. Radiotherapy target sites were randomly allocated (1:1) either 24 Gy in 12 fractions or 4 Gy in two fractions using minimisation and stratified by histology, treatment intent, and study centre. Randomisation was centralised through the Cancer Research UK and University College London Cancer Trials Centre. Patients, treating clinicians, and investigators were not masked to random assignments. The primary endpoint was time to local progression in the irradiated volume based on clinical and radiological evaluation and analysed on an intention-to-treat basis. The non-inferiority threshold aimed to exclude the chance that 4 Gy was more than 10% inferior to 24 Gy in terms of local control at 2 years (HR 1·37). Safety (in terms of adverse events) was analysed in patients who received any radiotherapy and who returned an adverse event form. FoRT is registered with ClinicalTrials.gov, NCT00310167, and the ISRCTN Registry, ISRCTN65687530, and this report represents the long-term follow-up. FINDINGS: Between April 7, 2006, and June 8, 2011, 614 target sites in 548 patients were randomly assigned either 24 Gy in 12 fractions (n=299) or 4 Gy in two fractions (n=315). At a median follow-up of 73·8 months (IQR 61·9-88·0), 117 local progression events were recorded, 27 in the 24 Gy group and 90 in the 4 Gy group. The 2-year local progression-free rate was 94·1% (95% CI 90·6-96·4) after 24 Gy and 79·8% (74·8-83·9) after 4 Gy; corresponding rates at 5 years were 89·9% (85·5-93·1) after 24 Gy and 70·4% (64·7-75·4) after 4 Gy (hazard ratio 3·46, 95% CI 2·25-5·33; p<0·0001). The difference at 2 years remains outside the non-inferiority margin of 10% at -13·0% (95% CI -21·7 to -6·9). The most common events at week 12 were alopecia (19 [7%] of 287 sites with 24 Gy vs six [2%] of 301 sites with 4 Gy), dry mouth (11 [4%] vs five [2%]), fatigue (seven [2%] vs five [2%]), mucositis (seven [2%] vs three [1%]), and pain (seven [2%] vs two [1%]). No treatment-related deaths were reported. INTERPRETATION: Our findings at 5 years show that the optimal radiotherapy dose for indolent lymphoma is 24 Gy in 12 fractions when durable local control is the aim of treatment. FUNDING: Cancer Research UK.


Assuntos
Linfoma de Zona Marginal Tipo Células B/radioterapia , Linfoma Folicular/radioterapia , Radioterapia/mortalidade , Idoso , Estudos de Equivalência como Asunto , Feminino , Seguimentos , Raios gama , Humanos , Linfoma de Zona Marginal Tipo Células B/patologia , Linfoma Folicular/patologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Taxa de Sobrevida
14.
J Environ Radioact ; 231: 106545, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33601321

RESUMO

Advancements in the development of gamma-ray spectrometers (GRS) have led to small and lightweight spectrometers that can be used under unmanned aerial vehicles (UAVs). Airborne GRS measurements are used to determine radionuclide concentrations in the ground, among which the natural occurring radionuclides 40K, 238U, and 232Th. For successful applications of these GRS sensors, it is important that absolute values of concentrations can be measured. To extract these absolute radionuclide concentrations, airborne gamma-ray data has to be corrected for measurement height. However, the current analysis models are only valid for the height range of 50-250 m. The purpose of this study is to develop a procedure that correctly predicts the true radionuclide concentration in the ground when measuring in the UAV operating range of 0-40 m. An analytical model is developed to predict the radiation footprint as a function of height. This model is used as a tool to properly determine a source-detector geometry to be used in Monte-Carlo simulations of detector response at various elevations between 0 and 40 m. The analytical model predicts that the smallest achievable footprint at 10 m height lies between 22 and 91 m and between 40 and 140 m at 20 m height. By using Monte-Carlo simulations it is shown that the analytical model correctly predicts the reduction in full energy peak gamma-rays, but does not predict the Compton continuum of a spectrum as a function of height. Therefore, Monte-Carlo simulations should be used to predict the shape and intensity of gamma-ray spectra as a function of height. A finite set of Monte-Carlo simulations at intervals of 5 m were used for the analysis of GRS measurements at heights up to 35 m. The resulting radionuclide concentrations at every height agree with the radionuclide concentration measured on the ground.


Assuntos
Monitoramento de Radiação , Raios gama , Método de Monte Carlo , Radioisótopos/análise , Espectrometria gama
15.
Ecotoxicol Environ Saf ; 208: 111727, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396058

RESUMO

Continuous depletion in tin productions has led to a newly emerging industry that is a tin by-product (amang) processing industry to harness mega tons of tin by-products produced in the past. Amang composed of profitable multi-heavy minerals and rare-earth elements. With poorly established safety and health practices in operating plant, amang poses extremely high radioactivity problem associated with high occupational ionizing radiation exposures to workers and continuously impacting the local environment with radioactive contamination from industrial effluent and solid waste into lithosphere and water bodies. The radioactivity level of 238U and 232Th series in the mineral varies from few hundreds up to ~200,000 and ~400,000 Bq kg-1 respectively and are potential to yield more than ~ 30,000 nGy h-1 of gamma (γ) radiation exposure to plant workers. The study found out that for 8 h of work time, a worker is estimated to receive an average effective dose of 0.1 mSv per day from external γ radiation source with a maximum up to 2 mSv per day for extreme exposure situation. Interferences of different exposure routes for examples inhalation of equivalent equilibrium concentration (ECC) of 222Rn and 220Rn progenies and airborne long-lived α particles from the dusty working environment could pose a higher total effective dose as much as 5 mSv per day and 115 mSv per year. The value is 5 times higher than the annual dose limit for designated radiation worker (20 mSv) in Peninsular Malaysia. The study found that 41% of the total received an effective dose received by a worker is contributed by 222Rn, 32% of airborne particulates and dust, 23% from external γ exposure and 4% from 220Rn. Based on radioecological risk assessment, the study found out that the aquatic environment is the highly exposed group to ionizing radiation from industrial effluent discharge and sand residues. With the impotent establishment of radiation protection in the industry, plus the country newly introduced long-term plan to revive tin mining as well as its accessory amang mineral, it is necessary for the government to harmonize current regulation to improve the worker safety and health as well as sustaining local environment.


Assuntos
Poluentes Radioativos do Ar/análise , Exposição Ocupacional , Doses de Radiação , Monitoramento de Radiação , Poeira , Meio Ambiente , Raios gama , Humanos , Malásia , Minerais , Mineração
16.
Radiat Res ; 195(2): 211-217, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33400791

RESUMO

Cells exposed to fast neutrons often exhibit a non-Poisson distribution of chromosome aberrations due to the high ionization density of the secondary reaction products. However, it is unknown whether lymphocytes exposed to californium-252 (252Cf) spectrum neutrons, of mean energy 2.1 MeV, demonstrate this same dispersion effect at low doses. Furthermore, there is no consensus regarding the relative biological effectiveness (RBE) of 252Cf neutrons. Dicentric and ring chromosome formations were assessed in human peripheral blood lymphocytes irradiated at doses of 12-135 mGy. The number of aberrations observed were tested for adherence to a Poisson distribution and the maximum low-dose relative biological effectiveness (RBEM) was also assessed. When 252Cf-irradiated lymphocytes were examined along with previously published cesium-137 (137Cs) data, RBEM values of 15.0 ± 2.2 and 25.7 ± 3.8 were found for the neutron-plus-photon and neutron-only dose components, respectively. Four of the five dose points were found to exhibit the expected, or close to the expected non-Poisson over-dispersion of aberrations. Thus, even at low doses of 252Cf fast neutrons, when sufficient lymphocyte nuclei are scored, chromosome aberration clustering can be observed.


Assuntos
Aberrações Cromossômicas/efeitos da radiação , Linfócitos/efeitos da radiação , Califórnio/farmacologia , Radioisótopos de Césio/farmacologia , Relação Dose-Resposta à Radiação , Nêutrons Rápidos/efeitos adversos , Raios gama/efeitos adversos , Humanos , Linfócitos/patologia , Eficiência Biológica Relativa
17.
Int J Mol Sci ; 22(1)2021 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-33466349

RESUMO

Following exposure to high doses of ionizing radiation, diverse strains of vertebrate species will manifest varying levels of radiation sensitivity. To understand the inter-strain cellular and molecular mechanisms of radiation sensitivity, two mouse strains with varying radiosensitivity (C3H/HeN, and CD2F1), were exposed to total body irradiation (TBI). Since Insulin-like Growth Factor-1 (IGF-1) signaling pathway is associated with radiosensitivity, we investigated the link between systemic or tissue-specific IGF-1 signaling and radiosensitivity. Adult male C3H/HeN and CD2F1 mice were irradiated using gamma photons at Lethal Dose-70/30 (LD70/30), 7.8 and 9.35 Gy doses, respectively. Those mice that survived up to 30 days post-irradiation, were termed the survivors. Mice that were euthanized prior to 30 days post-irradiation due to deteriorated health were termed decedents. The analysis of non-irradiated and irradiated survivor and decedent mice showed that inter-strain radiosensitivity and post-irradiation survival outcomes are associated with activation status of tissue and systemic IGF-1 signaling, nuclear factor erythroid 2-related factor 2 (Nrf2) activation, and the gene expression profile of cardiac mitochondrial energy metabolism pathways. Our findings link radiosensitivity with dysregulation of IGF-1 signaling, and highlight the role of antioxidant gene response and mitochondrial function in radiation sensitivity.


Assuntos
Antioxidantes/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Tolerância a Radiação/fisiologia , Transdução de Sinais/fisiologia , Animais , Relação Dose-Resposta à Radiação , Raios gama , Expressão Gênica/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C3H , Mitocôndrias/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Radiação Ionizante , Irradiação Corporal Total/métodos
18.
PLoS One ; 16(1): e0238209, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33513143

RESUMO

Ilomastat, a broad-spectrum inhibitor of matrix metalloproteinases (MMPs), has drawn attentions for its function in alleviating radiation damage. However, the detailed mechanisms of Ilomastat's protection from animal model remain not fully clear. In this study, the C57BL/6 mice were pre-administrated with Ilomastat or vihicle for 2 h, and then total body of mice were exposed to 6 Gy of γ-rays. The protective effect of Ilomastat on the hematopoietic system in the irradiated mice were investigated. We found that pretreatment with Ilomastat significantly reduced the level of TGF-ß1 and TNF-α, and elevated the number of bone marrow (BM) mononuclear cells in the irradiated mice. Ilomastat pretreatment also increased the fraction of BM hematopoietic progenitor cells (HPCs) and hematopoietic stem cells (HSCs) at day 30 after irradiation, and protected the spleen of mouse from irradiation. These results suggest that Ilomastat promotes the recovery of hematopoietic injury in the irradiated mice, and thus contributes to the survival of mouse after irradiation.


Assuntos
Ácidos Hidroxâmicos/farmacologia , Indóis/farmacologia , Lesões por Radiação/tratamento farmacológico , Irradiação Corporal Total/efeitos adversos , Animais , Raios gama/efeitos adversos , Células-Tronco Hematopoéticas/efeitos da radiação , Ácidos Hidroxâmicos/metabolismo , Indóis/metabolismo , Masculino , Inibidores de Metaloproteinases de Matriz/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Estresse Oxidativo/efeitos da radiação , Espécies Reativas de Oxigênio/farmacologia , Baço/efeitos da radiação , Fator de Crescimento Transformador beta1/efeitos da radiação , Fator de Necrose Tumoral alfa/efeitos da radiação
19.
Curr Microbiol ; 78(2): 544-557, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33388934

RESUMO

Colibactin and cytotoxic necrotizing factor 1 (Cnf 1) are cyclomodulins secreted by uropathogenic E. coli. In this study, uropathogenic E. coli expressing colibactin and Cnf 1 was exposed to antibiotics subMICs and gamma radiation to investigate their effects on its cytotoxicity and expression of colibactin. The test isolate was exposed to three subMIC levels of levofloxacin, ciprofloxacin, trimethoprim/sulfamethoxazole and ceftriaxone and irradiated with gamma rays at 10 and 24.4 Gy. The cytotoxicity for either antibiotic or gamma rays treated cultures was measured using MTT assay and the expression of colibactin encoding genes was determined by RT-PCR. Treatment with fluoroquinolones nearly abolished the cytotoxicity of E. coli isolate and significantly downregulated clbA gene expression at the tested subMICs (P ≤ 0.05) while trimethoprim/sulfamethoxazole treated cultures exerted significant downregulation of clbA and clbQ genes at 0.5 MIC only (P ≤ 0.05). Ceftriaxone treated cultured exhibited reduction in the cytotoxicity and insignificant effects on expression of clbA, clbQ and clbM genes. On contrast, significant upregulation in the expression of clbA and clbQ genes was observed in irradiated cultures (P ≤ 0.05). Fluoroquinolones reduced both the cytotoxicity of UPEC isolate and colibactin expression at different subMICs while ceftriaxone at subMICs failed to suppress the expression of genotoxin, colibactin, giving an insight to the risks associated upon their choice for UTI treatment. Colibactin expression was enhanced by gamma irradiation at doses resembling these received during pelvic radiotherapy which might contribute to post-radiotherapy complications.


Assuntos
Infecções por Escherichia coli , Proteínas de Escherichia coli , Policetídeos , Escherichia coli Uropatogênica , Antibacterianos/farmacologia , Proteínas de Escherichia coli/genética , Raios gama , Humanos , Proteínas de Transporte de Cátions Orgânicos , Peptídeos , Escherichia coli Uropatogênica/genética
20.
Environ Sci Pollut Res Int ; 28(18): 23287-23300, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33443739

RESUMO

Nicotine is an active pharmacological ingredient in cigarette smoke, which may negatively influence the male reproductive system and fertility. This study aims to investigate the effect of fractionated low-dose radiation (fractionated-LDR) and/or ellagic acid (EA) on nicotine-induced hormonal changes and testicular toxicity in rats. Nicotine was administrated orally (1 mg/kg) for 30 days, afterward, rats were treated with LDR (2 × 0.25 Gy/1-week interval), EA (10 mg/kg, 14 consecutive days p.o.), or a combination of both fractionated-LDR and EA. Rats were sacrificed 24 h after the last dose of treatment, then testes were dissected for histopathology examination, along with some biochemical parameters in serum and testicular tissue were evaluated. Nicotine-induced oxidative stress was evidenced by an increase in testicular thiobarbituric acid reactive substances (TBARS) and a decrease in reduced glutathione (GSH) content. Additionally, the activities of testicular androgenic enzymes were decreased, and the activity of serum lactate dehydrogenase (LDH) was significantly increased. The hormonal changes were verified by a noticeable reduction in follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone serum levels. Histological evaluation revealed that the testicular seminiferous tubules structure was distorted. On the contrary, fractionated-LDR plus EA attenuated the negative changes caused by nicotine observed through biochemical and histological findings. Accordingly, the exposure to fractionated-LDR combined with EA may be a promising candidate for treating hormonal changes and testicular toxicity caused by nicotine.


Assuntos
Ácido Elágico , Testículo , Animais , Ácido Elágico/metabolismo , Raios gama , Masculino , Nicotina/toxicidade , Estresse Oxidativo , Ratos , Testículo/metabolismo , Testosterona/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo
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