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1.
Cancer Radiother ; 24(5): 423-428, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32620459

RESUMO

Prostate cancer is the most common malignant tumour and represents the third cause of cancer-mortality in men. The management of prostate cancer has dramatically changed over the last decades, mainly due to improvement of diagnostic modalities and development of new therapeutic strategies. Imaging plays a key role in all the steps of prostate cancer management. In recent years, magnetic resonance imaging (MRI) and positron-emission tomography (PET) - computed tomography (CT) have emerged as two major tools for the detection of prostate cancer, tumour staging and treatment choice. Both MRI and PET-CT - using choline or prostate-specific membrane antigen (PSMA) as radiotracer - have become mandatory. This article presents the contribution of the latest advances in these two imaging techniques of prostate cancer and their future developments.


Assuntos
Antígenos de Superfície , Glutamato Carboxipeptidase II , Imagem por Ressonância Magnética/métodos , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons/métodos , Neoplasias da Próstata/diagnóstico por imagem , Adenocarcinoma/química , Adenocarcinoma/diagnóstico por imagem , Adenocarcinoma/radioterapia , Idoso , Radioisótopos de Carbono , Colina/análogos & derivados , Radioisótopos de Flúor , Humanos , Masculino , Imagem Multimodal/métodos , Recidiva Local de Neoplasia/diagnóstico por imagem , Neoplasias da Próstata/química , Neoplasias da Próstata/radioterapia , Compostos Radiofarmacêuticos , Ultrassonografia/métodos
2.
Nat Commun ; 11(1): 1736, 2020 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-32269227

RESUMO

Carbon-11 (11C) is one of the most ideal positron emitters for labeling bioactive molecules for molecular imaging studies. The lack of convenient and fast incorporation methods to introduce 11C into organic molecules often hampers the use of this radioisotope. Here, a fluoride-mediated desilylation (FMDS) 11C-labeling approach is reported. This method relies on thermodynamically favored Si-F bond formation to generate a carbanion, therefore enabling the highly efficient and speedy incorporation of [11C]CO2 and [11C]CH3I into molecules with diversified structures. It provides facile and rapid access to 11C-labeled compounds with carbon-11 attached at various hybridized carbons as well as oxygen, sulfur and nitrogen atoms with broad functional group tolerance. The exemplified syntheses of several biologically and clinically important radiotracers illustrates the potentials of this methodology.


Assuntos
Radioisótopos de Carbono/química , Fluoretos/química , Compostos de Organossilício/química , Acetoacetatos/química , Metilação , Racloprida/farmacologia , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/química
3.
PLoS One ; 15(4): e0231678, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32294128

RESUMO

The southern Gulf of Mexico (sGoM) is home to an extensive oil recovery and development infrastructure. In addition, the basin harbors sites of submarine hydrocarbon seepage and receives terrestrial inputs from bordering rivers. We used stable carbon, nitrogen, and radiocarbon analyses of bulk sediment organic matter to define the current baseline isoscapes of surface sediments in the sGoM and determined which factors might influence them. These baseline surface isoscapes will be useful for accessing future environmental impacts. We also examined the region for influence of hydrocarbon deposition in the sedimentary record that might be associated with hydrocarbon recovery, spillage and seepage, as was found in the northern Gulf of Mexico (nGoM) following the Deepwater Horizon (DWH) oil spill in 2010. In 1979, the sGoM experienced a major oil spill, Ixtoc 1. Surface sediment δ13C values ranged from -22.4‰ to -19.9‰, while Δ14C values ranged from -337.1‰ to -69.2‰. Sediment δ15N values ranged from 2.8‰ to 7.2‰, while the %C on a carbonate-free basis ranged in value of 0.65% to 3.89% and %N ranged in value of 0.09% to 0.49%. Spatial trends for δ13C and Δ14C were driven by water depth and distance from the coastline, while spatial trends for δ15N were driven by location (latitude and longitude). Location and distance from the coastline were significantly correlated with %C and %N. At depth in two of twenty (10%) core profiles, we found negative δ13C and Δ14C excursions from baseline values in bulk sedimentary organic material, consistent with either oil-residue deposition or terrestrial inputs, but likely the latter. We then used 210Pb dating on those two profiles to determine the time in which the excursion-containing horizons were deposited. Despite the large spill in 1979, no evidence of hydrocarbon residue remained in the sediments from this specific time period.


Assuntos
Radioisótopos de Carbono/análise , Monitoramento Ambiental/estatística & dados numéricos , Sedimentos Geológicos/análise , Datação Radiométrica/estatística & dados numéricos , Isótopos de Carbono/análise , Golfo do México , Radioisótopos de Chumbo/análise , Nitrogênio/análise
4.
Medicine (Baltimore) ; 99(16): e19620, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32311931

RESUMO

For the diagnosis of mild cognitive impairment (MCI) and Alzheimer disease (AD), variable neuroimaging and neuropsychological tests have been used. We aimed to evaluate the correlation of neuropsychological domain with new amyloid positron emission tomography (PET) study and to validate the availability of new PET tracer.We enrolled 20 patients who underwent C-PiB-PET/CT, new PET tracer F-FC119S PET/CT from November, 2014 to July, 2015. Among them, 10 patients were diagnosed with AD and 10 patients with MCI. The current version of Seoul Neuropsychological Screening Battery (SNSB) II was performed for cognitive evaluation. Each parameter of SNSB was compared between 2 patient groups. Spearman correlation analysis between value of SNSB domain and standardized uptake value ratio (SUVR) of PET was also performed.The AD group presented significant poor z-score in Korean-Boston Naming Test(K-BNT) (P = .01),copy score of Rey Complex Figure Test (RCFT) (P = .049), immediate (P = .028)and delayed memory of Seoul Verbal Learning Test (SVLT) (P = .028), recognition of RCFT (P = .004), "animal" of Controlled Oral Word Association Test (COWAT) (P = .041), color reading of Korean-Color Word Stroop test (K-CWST) (P = .014), and Digit Symbol Coding (DSC) (P = .007) compared with MCI group. That means, except attention domain, all other cognitive domains were relatively impaired in AD compared with MCI. In correlation analysis, we found that poor performances on copy score of RCFT in MCI groups were associated with great beta amyloid burden in frontal area in both C-PiB-PET/CT and F-FC119S PET/CT. In AD group, F-FC119S PET presented more extensive correlation in each cognitive domain with multiple cortical areas compared with C-PiB-PET.The degree of amyloid burden assessed on F-FC119S PET was significantly correlated with neuropsychological test in AD, and also MCI patients. The combination of neuropsychological evaluation with novel F-FC119S PET/CT can be used for valid biomarker for MCI and AD.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Amiloide/metabolismo , Disfunção Cognitiva/diagnóstico por imagem , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons/métodos , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/metabolismo , Doença de Alzheimer/psicologia , Compostos de Anilina , Benzotiazóis , Radioisótopos de Carbono , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/psicologia , Feminino , Radioisótopos de Flúor , Humanos , Masculino , Pessoa de Meia-Idade , Neuroimagem/métodos , Testes Neuropsicológicos , Piridinas , Traçadores Radioativos , Tiazóis
5.
Chemosphere ; 250: 126230, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32234616

RESUMO

The Swiss disposal concept foresees that carbon-14 (14C) is predominantly released from irradiated steel disposed of in a cement-based repository for low- and intermediate-level radioactive waste. To predict how 14C migrates in the cementitious environment of the repository near field and subsequently in the host rock, knowledge about the carbon speciation during anoxic steel corrosion in alkaline conditions is therefore essential. To this end, batch-type corrosion experiments with carbon-containing zero-valent iron (ZVI) powders subject to oxidative pre-treatments were carried out in NaOH solution at pH 11 and 12.5. Alkanes and alkenes (C1-C7) were identified in the gas phase and produced on the iron surface by a Fischer-Tropsch type mechanism. The kind of oxidative pre-treatment has an effect on the production rate of hydrocarbons (HCs). In the liquid phase, carboxylic acids were identified and produced during the oxidative pre-treatment of the ZVI powders. They are released instantaneously from the oxide layer upon contact with the alkaline solution. The kind of oxidative treatment and the exposure time to oxic conditions directly influence the amount of carboxylic acids accommodated in the oxide layer.


Assuntos
Carbono/química , Ferro/química , Poluentes Químicos da Água/química , Radioisótopos de Carbono , Corrosão , Compostos Orgânicos , Oxirredução , Aço/química
6.
Medicine (Baltimore) ; 99(14): e19662, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32243399

RESUMO

The value of dual imaging mode for the severity assessment of Parkinson disease (PD) is explored by conducting positron emission tomography computed tomography (PET/CT) double imaging using combined 18-fluorine flurodeoxyglucose (F-FDG) brain metabolism and 11C-2ß-carbomethoxy-3ß-(4-fluorophenyl) tropane (C-CFT) brain dopamine transporter (DAT).A total of 102 patients with PD and 50 healthy people in the control group are enrolled for the PET/CT dual imaging of F-FDG brain metabolism and C-CFT brain DAT. The characteristics of F-FDG PET/CT and C-CFT PET/CT imaging are analyzed by delineating the region of interest. Differences in the glucose metabolism and DAT distribution in the basal ganglia of patients with PD and healthy control group in the PET/CT imaging and the radioactive distribution characteristics of cerebral cortex in glucose metabolism imaging are compared. The characteristics of PET/CT imaging of C-CFT brain DAT in the ganglion region in absorbing C-CFT in different PD groups are analyzed.Compared with the healthy control group, changes in the cerebral glucose metabolism in the PD group mainly occur due to the increased symmetry metabolism of the nucleus of bilateral basal ganglia and the decreased metabolism of the cerebral cortex as shown in the F-FDG PET/CT images. With disease progression, the bilateral parietal, frontal, temporal, and occipital leaves showed different degrees of FDG metabolism. Statistically significant difference is observed for theC-CFT absorption among the caudate nucleus and the anterior, middle, and posterior nuclei of the bilateral basal ganglia of the PD and healthy control groups. In the PD group, the bilateral caudate nucleus and the anterior, middle, and posterior parts of the putamen show decreased DAT distribution. Regardless of unilateral or bilateral symptoms, the DAT distribution in the nucleus of the contralateral basal ganglia and in the posterior part of the nucleus is substantially reduced.PET/CT dual imaging by F-FDG PET/CT combined with C-CFT PET/CT features high application value for the severity assessment of PD.


Assuntos
Radioisótopos de Carbono , Cocaína/análogos & derivados , Radioisótopos de Flúor , Doença de Parkinson/diagnóstico por imagem , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons/métodos , Idoso , Gânglios da Base/diagnóstico por imagem , Gânglios da Base/metabolismo , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Feminino , Glucose/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/metabolismo , Estudos Prospectivos , Índice de Gravidade de Doença
7.
Nature ; 580(7804): 506-510, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32322061

RESUMO

Pottery is one of the most commonly recovered artefacts from archaeological sites. Despite more than a century of relative dating based on typology and seriation1, accurate dating of pottery using the radiocarbon dating method has proven extremely challenging owing to the limited survival of organic temper and unreliability of visible residues2-4. Here we report a method to directly date archaeological pottery based on accelerator mass spectrometry analysis of 14C in absorbed food residues using palmitic (C16:0) and stearic (C18:0) fatty acids purified by preparative gas chromatography5-8. We present accurate compound-specific radiocarbon determinations of lipids extracted from pottery vessels, which were rigorously evaluated by comparison with dendrochronological dates9,10 and inclusion in site and regional chronologies that contained previously determined radiocarbon dates on other materials11-15. Notably, the compound-specific dates from each of the C16:0 and C18:0 fatty acids in pottery vessels provide an internal quality control of the results6 and are entirely compatible with dates for other commonly dated materials. Accurate radiocarbon dating of pottery vessels can reveal: (1) the period of use of pottery; (2) the antiquity of organic residues, including when specific foodstuffs were exploited; (3) the chronology of sites in the absence of traditionally datable materials; and (4) direct verification of pottery typochronologies. Here we used the method to date the exploitation of dairy and carcass products in Neolithic vessels from Britain, Anatolia, central and western Europe, and Saharan Africa.


Assuntos
Arqueologia/métodos , Cerâmica/química , Cerâmica/história , Datação Radiométrica/métodos , Datação Radiométrica/normas , África do Norte , Arqueologia/normas , Teorema de Bayes , Radioisótopos de Carbono , Europa (Continente) , Ácidos Graxos/química , Ácidos Graxos/isolamento & purificação , Alimentos/história , História Antiga , Lipídeos/química , Lipídeos/isolamento & purificação , Espectrometria de Massas
8.
Ecotoxicol Environ Saf ; 195: 110482, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32200149

RESUMO

The impact of whole digestate (WD) and its fractions (solid [SD] and liquid [LD]) on 14C-phenanthrene mineralization in soil over 90 d contact time was investigated. The 14C-phenanthrene spiked soil was aged for 1, 30, 60 and 90 d. Analysis of water-soluble nitrogen, phosphorus, total (organic and inorganic) carbon, and quantitative bacterial count were conducted at each time point to assess their impact on mineralization of 14C-phenanthrene in soils. Indigenous catabolic activity (total extents, maximum rates and lag phases) of 14C-phenanthrene mineralization were measured using respirometric soil slurry assay. The soil amended with WD outperformed the SD and LD fractions as well as showed a shorter lag phase, higher rate and extent of mineralization throughout the study. The digestates improved (P < 0.05) the microbial population and nutritive content of the soil. However, findings showed that spiking soil with phenanthrene generally reduced the growth of microbial populations from 1 to 90 d and gave a lower nutritive content in comparison with the non-spiked soil. Also, soil fertility and bacteria count were major factors driving 14C-phenanthrene mineralization. Particularly, the non-phenanthrene degraders positively influenced the cumulative mineralization of 14C-phenanthrene after 60 d incubation. Therefore, the digestates (residue from anaerobic digestion) especially WD, which enhanced 14C-phenanthrene mineralization of the soil without minimal basal salts medium nor additional degraders should be further exploited for sustainable bioremediation of PAHs contaminated soil.


Assuntos
Fenantrenos/metabolismo , Poluentes do Solo/metabolismo , Solo/química , Biodegradação Ambiental , Carbono/análise , Radioisótopos de Carbono , Nitrogênio/análise , Fósforo/análise , Microbiologia do Solo
9.
Food Chem ; 320: 126601, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32208180

RESUMO

Acrylamide (AA) formation during coffee roasting happens rapidly, reaching a peak value within the first minutes of roasting followed by a fast decrease to reach an asymptote at approximately 200 µg/kg. Today, the mechanisms by which AA is reduced during roasting remain unclear. In this research, the fate of AA during roasting followed by drip brewed-like extraction was studied using 14C-radiolabeled (14C-AA) and 13C-labeled (13C3-AA) materials. Results showed that 28% of the spiked 14C-AA was lost during the roasting process, presumably by degradation to volatile compounds and 25% was non-extractable; therefore, appeared bound to the matrix. About 50% of initial AA went into the water extract, either unchanged or transformed by conjugation/binding. The release of bound acrylamide was further evidenced by increasing levels of 13C3-AA over prolonged roasting times. In addition, the absence of 14C activity in the hexane extracts suggested acrylamide not to bind to any lipophilic material.


Assuntos
Acrilamida/química , Café/química , Manipulação de Alimentos , Acrilamida/análise , Radioisótopos de Carbono , Temperatura Alta
10.
Isotopes Environ Health Stud ; 56(2): 95-110, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32174280

RESUMO

Severe droughts during the dry season and floodings during the rainy season are among the major problems encountered in the valleys along the Ping River in Thailand. Improving our understanding of the groundwater resources in this agricultural area is an important issue for the sustainable development of the region. Hence, in order to gain understanding on the groundwater flow dynamics in the unconsolidated shallow aquifers along the Ping River, stable (13C, 18O, 2H, noble gases) and radioactive (3H, 14C) isotope techniques were combined with hydrogeochemical tools. The comprehensive interpretation of the chemical and isotope data consistently showed different origins for groundwater in the northern and southern areas of the investigated aquifers. Groundwaters in the northern part have younger 3H/3He ages, are less mineralized, and have suffered a stronger evaporation than groundwaters in the southern part of the aquifer. Overall, our results are consistent with the hydrogeological situation of the investigated area, namely shallow groundwaters and a spatially extended recharge. 3H/3He apparent ages indicated that young groundwater (<50 years) is present in all the investigated wells. Elevated concentrations of some pollutants (nitrate and phosphate) in parts of the aquifer evidenced a relatively high vulnerability of the aquifer to surface pollution.


Assuntos
Monitoramento Ambiental/métodos , Água Subterrânea/química , Rios/química , Poluentes Químicos da Água/análise , Poços de Água , Agricultura , Isótopos de Carbono/análise , Radioisótopos de Carbono/análise , Marcação por Isótopo , Nitratos/análise , Fosfatos/análise , Estações do Ano , Tailândia
11.
Brain ; 143(3): 1010-1026, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-32179883

RESUMO

The clinical syndromes of frontotemporal dementia are clinically and neuropathologically heterogeneous, but processes such as neuroinflammation may be common across the disease spectrum. We investigated how neuroinflammation relates to the localization of tau and TDP-43 pathology, and to the heterogeneity of clinical disease. We used PET in vivo with (i) 11C-PK-11195, a marker of activated microglia and a proxy index of neuroinflammation; and (ii) 18F-AV-1451, a radioligand with increased binding to pathologically affected regions in tauopathies and TDP-43-related disease, and which is used as a surrogate marker of non-amyloid-ß protein aggregation. We assessed 31 patients with frontotemporal dementia (10 with behavioural variant, 11 with the semantic variant and 10 with the non-fluent variant), 28 of whom underwent both 18F-AV-1451 and 11C-PK-11195 PET, and matched control subjects (14 for 18F-AV-1451 and 15 for 11C-PK-11195). We used a univariate region of interest analysis, a paired correlation analysis of the regional relationship between binding distributions of the two ligands, a principal component analysis of the spatial distributions of binding, and a multivariate analysis of the distribution of binding that explicitly controls for individual differences in ligand affinity for TDP-43 and different tau isoforms. We found significant group-wise differences in 11C-PK-11195 binding between each patient group and controls in frontotemporal regions, in both a regions-of-interest analysis and in the comparison of principal spatial components of binding. 18F-AV-1451 binding was increased in semantic variant primary progressive aphasia compared to controls in the temporal regions, and both semantic variant primary progressive aphasia and behavioural variant frontotemporal dementia differed from controls in the expression of principal spatial components of binding, across temporal and frontotemporal cortex, respectively. There was a strong positive correlation between 11C-PK-11195 and 18F-AV-1451 uptake in all disease groups, across widespread cortical regions. We confirmed this association with post-mortem quantification in 12 brains, demonstrating strong associations between the regional densities of microglia and neuropathology in FTLD-TDP (A), FTLD-TDP (C), and FTLD-Pick's. This was driven by amoeboid (activated) microglia, with no change in the density of ramified (sessile) microglia. The multivariate distribution of 11C-PK-11195 binding related better to clinical heterogeneity than did 18F-AV-1451: distinct spatial modes of neuroinflammation were associated with different frontotemporal dementia syndromes and supported accurate classification of participants. These in vivo findings indicate a close association between neuroinflammation and protein aggregation in frontotemporal dementia. The inflammatory component may be important in shaping the clinical and neuropathological patterns of the diverse clinical syndromes of frontotemporal dementia.


Assuntos
Demência Frontotemporal/metabolismo , Inflamação/metabolismo , Agregados Proteicos , Idoso , Carbolinas/metabolismo , Radioisótopos de Carbono/metabolismo , Estudos de Casos e Controles , Proteínas de Ligação a DNA/metabolismo , Feminino , Demência Frontotemporal/complicações , Humanos , Inflamação/complicações , Isoquinolinas/metabolismo , Masculino , Microglia/metabolismo , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons , Ligação Proteica , Tauopatias/metabolismo
12.
Nature ; 578(7795): 409-412, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32076219

RESUMO

Atmospheric methane (CH4) is a potent greenhouse gas, and its mole fraction has more than doubled since the preindustrial era1. Fossil fuel extraction and use are among the largest anthropogenic sources of CH4 emissions, but the precise magnitude of these contributions is a subject of debate2,3. Carbon-14 in CH4 (14CH4) can be used to distinguish between fossil (14C-free) CH4 emissions and contemporaneous biogenic sources; however, poorly constrained direct 14CH4 emissions from nuclear reactors have complicated this approach since the middle of the 20th century4,5. Moreover, the partitioning of total fossil CH4 emissions (presently 172 to 195 teragrams CH4 per year)2,3 between anthropogenic and natural geological sources (such as seeps and mud volcanoes) is under debate; emission inventories suggest that the latter account for about 40 to 60 teragrams CH4 per year6,7. Geological emissions were less than 15.4 teragrams CH4 per year at the end of the Pleistocene, about 11,600 years ago8, but that period is an imperfect analogue for present-day emissions owing to the large terrestrial ice sheet cover, lower sea level and extensive permafrost. Here we use preindustrial-era ice core 14CH4 measurements to show that natural geological CH4 emissions to the atmosphere were about 1.6 teragrams CH4 per year, with a maximum of 5.4 teragrams CH4 per year (95 per cent confidence limit)-an order of magnitude lower than the currently used estimates. This result indicates that anthropogenic fossil CH4 emissions are underestimated by about 38 to 58 teragrams CH4 per year, or about 25 to 40 per cent of recent estimates. Our record highlights the human impact on the atmosphere and climate, provides a firm target for inventories of the global CH4 budget, and will help to inform strategies for targeted emission reductions9,10.


Assuntos
Atmosfera/química , Combustíveis Fósseis/história , Combustíveis Fósseis/provisão & distribução , Atividades Humanas/história , Metano/análise , Metano/história , Biomassa , Radioisótopos de Carbono , Carvão Mineral/história , Carvão Mineral/provisão & distribução , Aquecimento Global/prevenção & controle , Aquecimento Global/estatística & dados numéricos , História do Século XVIII , História do Século XIX , História do Século XX , História do Século XXI , Camada de Gelo/química , Metano/química , Gás Natural/história , Gás Natural/provisão & distribução , Petróleo/história , Petróleo/provisão & distribução
13.
J Environ Radioact ; 216: 106188, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32056792

RESUMO

Environmental radiocarbon (14C) monitoring is gaining importance in China due to the recent rapid development of the nuclear industry. In this study, synthetic benzoic acid samples with the fingerprint of environmental 14C were generated by using the synthesis method, and the specific activity of 14C was determined using the liquid scintillation counting (LSC) method. The ultra-performance liquid chromatography (UPLC) analysis was performed in chemical properties test and results showed that the mean assay and yield of synthetic benzoic acid were 91.8% ± 2.4% and 84.5% ± 2.0%, respectively. Under adopted LSC counting conditions, the minimum detectable activity (MDA) of 64 Bq/kg C was achieved in our laboratory. The method's linearity was examined using a series of spiked samples, along with the 14C-free samples. The results showed a wide linear range up to 2000 Bq/kg C. Reproducible results were obtained from three batches of experiments with deviations in the intra-group and inter-group of 0.38%-3.06% and 1.24%-3.55%, respectively. Long-term evaluation of the system was found to be very stable (over 5 months storage) with the relative standard deviations of <1%. In addition, field applications in the vicinity of a nuclear power plant demonstrated that 14C data measured by our method was consistent with the accelerator mass spectrometry (AMS) method, suggesting the method's precision can meet the requirement of 14C monitoring near the nuclear facility. This is the first study to report the use of synthetic benzoic acid in environmental 14C monitoring, and it provides a new approach for improving the environmental 14C monitoring network.


Assuntos
Monitoramento de Radiação , Ácido Benzoico , Radioisótopos de Carbono , China , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Centrais Nucleares
14.
Clin Nucl Med ; 45(3): 228-229, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31977460

RESUMO

Focal nodular fat sparing of the liver may show, on PET/CT imaging, prominent tracer uptake over a background of less metabolic features of steatosis. This finding, already reported with F-FDG, may mimic primary or secondary neoplasms of the liver. The authors present an additional case of nodular fat-sparing hepatic parenchyma exhibiting C-choline avidity during PET/CT assessment for biochemical recurrence of prostate cancer.


Assuntos
Tecido Adiposo/patologia , Radioisótopos de Carbono , Colina , Fígado/diagnóstico por imagem , Fígado/patologia , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons , Idoso , Diagnóstico Diferencial , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias da Próstata/diagnóstico por imagem , Recidiva
15.
PLoS One ; 15(1): e0228254, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978207

RESUMO

Warsaw grouper, Hyporthodus nigritus, is a western Atlantic Ocean species typically found at depths between 55 and 525 m. It is listed as a species of concern by the U.S. National Marine Fisheries Service and as near threatened by the International Union for the Conservation of Nature. However, little information exists on the species' life history in the northern Gulf of Mexico (nGOM) and its stock status in that region is currently unknown. Age of nGOM Warsaw grouper was investigated via opaque zone counts in otolith thin sections (max age = 61 y), and then the bomb 14C chronometer was employed to validate the accuracy of age estimates. Otolith cores (n = 14) were analyzed with accelerator mass spectrometry and resulting Δ14C values overlain on a loess regression computed for a regional coral and known-age red snapper Δ14C time series. Residual analysis between predicted Δ14C values from the loess regression versus Warsaw grouper otolith core Δ14C values indicated no significant difference in the two data series. Therefore, the accuracy of otolith-based aging was validated, which enabled growth and longevity estimates to be made for nGOM Warsaw grouper. Dissolved inorganic carbon (DIC) Δ14C values collected from the nGOM support the inference that juvenile Warsaw grouper occur in shelf waters (<200 m) since DIC Δ14C values in this depth range are enriched in 14C and similar to the Δ14C values from otolith cores. A Bayesian model was fit to fishery-dependent age composition data and produced von Bertalanffy growth function parameters of L∞ = 1,533 mm, k = 0.14 y-1, and t0 = 1.82 y. Fishing mortality also was estimated in the model, which resulted in a ratio of fishing to natural mortality of 5.1:1. Overall, study results indicate Warsaw grouper is a long-lived species that is estimated to have experienced significant overfishing in the nGOM, with the age of most landed fish being <10 y.


Assuntos
Membrana dos Otólitos/química , Perciformes/fisiologia , Datação Radiométrica/métodos , Animais , Teorema de Bayes , Radioisótopos de Carbono/química , Pesqueiros , Golfo do México , Longevidade , Espectrometria de Massas , Perciformes/crescimento & desenvolvimento
16.
Nat Med ; 26(2): 281-288, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31959988

RESUMO

Although aberrations in the number and function of glutamate AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors are thought to underlie neuropsychiatric disorders, no methods are currently available for visualizing AMPA receptors in the living human brain. Here we developed a positron emission tomography (PET) tracer for AMPA receptors. A derivative of 4-[2-(phenylsulfonylamino)ethylthio]-2,6-difluoro-phenoxyacetamide radiolabeled with 11C ([11C]K-2) showed specific binding to AMPA receptors. Our clinical trial with healthy human participants confirmed reversible binding of [11C]K-2 in the brain according to Logan graphical analysis (UMIN000020975; study design: non-randomized, single arm; primary outcome: dynamics and distribution volumes of [11C]K-2 in the brain; secondary outcome: adverse events of [11C]K-2 during the 4-10 d following dosing; this trial met prespecified endpoints). In an exploratory clinical study including patients with epilepsy, we detected increased [11C]K-2 uptake in the epileptogenic focus of patients with mesial temporal lobe epilepsy, which was closely correlated with the local AMPA receptor protein distribution in surgical specimens from the same individuals (UMIN000025090; study design: non-randomized, single arm; primary outcome: correlation between [11C]K-2 uptake measured with PET before surgery and AMPA receptor protein density examined by biochemical study after surgery; secondary outcome: adverse events during the 7 d following PET scan; this trial met prespecified endpoints). Thus, [11C]K-2 is a potent PET tracer for AMPA receptors, potentially providing a tool to examine the involvement of AMPA receptors in neuropsychiatric disorders.


Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Radioisótopos de Carbono/química , Fenoxiacetatos/farmacocinética , Receptores de AMPA/metabolismo , Adulto , Animais , Cromatografia Líquida , Feminino , Voluntários Saudáveis , Humanos , Masculino , Tomografia por Emissão de Pósitrons , Ligação Proteica , Ratos , Ratos Sprague-Dawley , Espectrometria de Massas em Tandem , Tomografia Computadorizada de Emissão de Fóton Único , Resultado do Tratamento , Adulto Jovem
17.
Psychiatry Clin Neurosci ; 74(4): 263-269, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31943514

RESUMO

AIM: The aim of the study was to test: (i) if D2 /D3 binding in three functional subsections of striatum is different in patients with severe major depressive episodes than in controls; and (ii) if this difference is normalized after electroconvulsive therapy (ECT). METHODS: Nine inpatients were examined with positron emission tomography (PET) and the radioligand [11 C]raclopride before and after an average of 8.4 ECT sessions. Treatment response was assessed using the Montgomery-Åsberg Depression Rating Scale. Nine age- and sex-matched controls were examined twice with PET and [11 C]raclopride. RESULTS: [11 C]raclopride binding was significantly lower in all three subsections of striatum in patients compared to controls (Cohen's dz , 1.14-1.68; P = 0.003-0.027). Montgomery-Åsberg Depression Ratings decreased significantly after ECT (P < 0.001; Cohen's dz , 2.9). ECT had no statistically significant effect on [11 C]raclopride binding, although post-ECT binding estimates were more similar to those obtained in controls in all subsections of striatum. CONCLUSION: Using PET and [11 C]raclopride, we found support for the notion that severe major depressive episodes are associated with significantly lower dopamine D2 /D3 binding in all three subsections of striatum compared to controls. We noted no significant effect on D2 /D3 binding in the patient group after response to ECT.


Assuntos
Transtorno Depressivo Maior , Antagonistas de Dopamina/farmacologia , Eletroconvulsoterapia , Racloprida/farmacologia , Receptores de Dopamina D2 , Receptores de Dopamina D3 , Adulto , Idoso , Mapeamento Encefálico , Radioisótopos de Carbono , Corpo Estriado , Transtorno Depressivo Maior/fisiopatologia , Transtorno Depressivo Maior/terapia , Dopamina/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons , Ligação Proteica , Receptores de Dopamina D2/metabolismo , Receptores de Dopamina D3/metabolismo
18.
Sci Total Environ ; 704: 135398, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-31836228

RESUMO

The differences of PBDE absorption, accumulation, and metabolism in different cultivars of the same crop are rarely explored. This study used 14C tracing to fully demonstrate the uptake and transformation of soil-borne BDE209 in three rice cultivars, including two indica (HHZ and YD1) and one japonica cultivars (NJ3). Results showed that about 6.9, 17.2, and 17.4% of the applied 14C-BDE209 were transformed to 14C-metabolites in soils planted with HHZ, YD1, and NJ3, respectively. The 14C-BDE209 and its 14C-metabolites in soil could be absorbed by the rice and gradually transported to its root, stem, leaf, and grain, with the total whole-plant uptake of 8.52, 4.55 and 3.43 nmol for HHZ, YD1, and NJ3, respectively. The cultivar of HHZ had the greatest whole-plant 14C absorption but the lowest ΣPBDEs residues in its grain, with the ΣPBDEs of 421.8, 454.2 and 967.0 ng g-1 for HHZ, YD1, and NJ3, respectively. BDE-209 accounted for 90%, 31% and 50% of the ΣPBDEs in the grain from HHZ, YD1, and NJ3, respectively. The estimated daily intake (EDI) amounts of ΣPBDEs were 928, 1056, and 2675 ng kg-1 bw d-1 via consuming rice grains from HHZ, YD1, and NJ3, respectively, which were below the safe threshold limits for human consumption. This study proved the different BDE-209 absorption, accumulation and transformation in different rice cultivars, which potentially suggests the need of considering cultivar differences in assessing the dietary risks of PBDEs.


Assuntos
Éteres Difenil Halogenados/metabolismo , Oryza/metabolismo , Poluentes do Solo/metabolismo , Transporte Biológico , Radioisótopos de Carbono , Grão Comestível , Humanos , Folhas de Planta , Solo
19.
Physiol Plant ; 168(3): 725-735, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31381158

RESUMO

14 C methods were applied to young, woody, branched and well-watered cork oak (Quercus suber L.) plants to determine carbon assimilation and its distribution among plant organs. Carbon assimilation rates by attached leaves clamped in a foliar 14 CO2 assimilation chamber containing 3.7 × 104 Bq of a portable ventilated diffusion porometer were measured at different 14 CO2 pulse-labeling periods (15, 30, 45, 60 and 120 s) in summer. Allocation of recently fixed C by attached leaves within plants was evaluated 7 days after a 60-min of 5.6 MBq of 14 CO2 pulse-labeling in late winter. 14 CO2 pulse-labeling was separately induced on leaves of a lower branch, two opposite branches at the same lower level, a middle branch and a top branch. 14 C activity incorporated into the plants was measured by liquid scintillation and autoradiography. Our results show the optimum 14 CO2 pulse-labeling period is between 15 and 30 s, which corresponds to 9.81 ± 0.15 and 9.16 ± 0.12 µmol m-2 s-1 C assimilation rates in summer, respectively. The investment of current assimilates ranged from 18 to 29% in leaves, 1 to 7% in lateral branches, 0 to 3% in the stem and over 65% in roots, in late winter. Roots displayed the greatest sink strength for the total 14 C recovered by whole-plants. These results were expected because the trial was done in winter, when cork oak does not produce their leaves. Our results highlight the contribution of current assimilates for growth and maintenance of roots, in young woody plants under Mediterranean climate.


Assuntos
Carbono/metabolismo , Folhas de Planta/metabolismo , Quercus/metabolismo , Dióxido de Carbono/metabolismo , Radioisótopos de Carbono/análise , Estações do Ano
20.
Chemosphere ; 238: 124558, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31442772

RESUMO

Graphene-based nanomaterials (GNMs) have been touted as miracle materials due to their extraordinary properties that can benefit many industries, including in agriculture and for environmental remediation. While improvement in nutrient delivery and the ability to adsorb environmental contaminants have been demonstrated, what happens to GNMs in soil is a question that has not been addressed. The main aim of this study was to investigate their degradation in soil to have a better understanding of their environmental fate. Using radioisotope techniques, this study assessed the potential mineralisation and release of graphene oxide (GO), one of the most commonly used forms of graphene. Results revealed that the conversion of GO to carbon dioxide was negligible (<2%) in microbially-active soils. GO remaining in soil was also not readily released by water extractions. The lack of mineralisation and release is indicative of GO's high (bio)degradation stability which is likely due to its limited availability resulting from its rapid homo/hetero-aggregation. Over-all, the results provide new and important information on the environmental fate of graphene nanomaterials applied to soils.


Assuntos
Dióxido de Carbono/metabolismo , Radioisótopos de Carbono/análise , Recuperação e Remediação Ambiental , Grafite/análise , Minerais/metabolismo , Nanoestruturas/administração & dosagem , Solo/química , Adsorção , Agricultura , Grafite/química
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