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1.
BMC Geriatr ; 24(1): 112, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38287253

RESUMO

BACKGROUND: Iron deficiency (ID) is often associated with other comorbidities in older patients and is a factor of morbimortality. However, the prevalence of ID remains poorly documented in this population. METHODS: The CARENFER PA study was a French multicenter cross-sectional study whose objective was to evaluate ID in patients (> 75 years) admitted to a geriatric unit. The primary endpoint was the ID prevalence defined as: serum ferritin < 100 µg/L and/or transferrin saturation coefficient (TSAT) < 20%. The Short Physical Performance Battery (SPPB) test was used to identify older patients at high risk of adverse events (e.g., disability, falls, hospitalization, death). RESULTS: A total of 888 patients (mean age, 85.2 years; women, 63.5%) from 16 French centers were included from October 2022 to December 2022. The prevalence of ID was 57.6% (95% CI, 54.3-60.9) in the cohort of older patients (62.6% in anemic and 53.3% in non-anemic patients; p = 0.0062). ID prevalence increased significantly with the presence of more than three comorbidities (65.6% vs. 55.9%; p = 0.0274), CRP ≥ 12 mg/L (73.0% vs. 49.3%; p < 0.001) and treatment that may influence ID/anemia (60.5% vs. 49.6%; p = 0.0042). In multivariate analysis, only CRP ≥ 12 mg/L was an independent predictive factor of ID (odds ratio, 2.78; 95% CI, 1.92-4.08; p < 0.001). SPPB scores were low (0-6) in 60.5% of patients with ID versus 48.6% of patients without ID (p = 0.0076). CONCLUSION: More than half of older patients had ID, including non-anemic patients. ID was associated with the presence of inflammation and a low SPPB score. TRIAL REGISTRATION: NCT05514951.


Assuntos
Anemia Ferropriva , Deficiências de Ferro , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Estudos Transversais , Hospitalização , Prevalência
2.
Environ Sci Technol ; 52(1): 298-307, 2018 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-29185731

RESUMO

Monitoring human exposure to pesticides and pesticide residues (PRs) remains crucial for informing public health policies, despite strict regulation of plant protection product and biocide use. We used 72 low-cost silicone wristbands as noninvasive passive samplers to assess cumulative 5-day exposure of 30 individuals to polar PRs. Ethyl acetate extraction and LC-MS/MS analysis were used for the identification of PRs. Thirty-one PRs were detected of which 15 PRs (48%) were detected only in worn wristbands, not in environmental controls. The PRs included 16 fungicides (52%), 8 insecticides (26%), 2 herbicides (6%), 3 pesticide derivatives (10%), 1 insect repellent (3%), and 1 pesticide synergist (3%). Five detected pesticides were not approved for plant protection use in the EU. Smoking and dietary habits that favor vegetable consumption were associated with higher numbers and higher cumulative concentrations of PRs in wristbands. Wristbands featured unique PR combinations. Our results suggest both environment and diet contributed to PR exposure in our study group. Silicone wristbands could serve as sensitive passive samplers to screen population-wide cumulative dietary and environmental exposure to authorized, unauthorized and banned pesticides.


Assuntos
Resíduos de Praguicidas , Praguicidas , Cromatografia Líquida , Monitoramento Ambiental , Humanos , Silicones , Espectrometria de Massas em Tandem
3.
Cerebrovasc Dis ; 42(1-2): 106-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27071040

RESUMO

BACKGROUND: This study aimed at assessing the changes in brain metabolism related to white-matter magnetic resonance (MR) hyperintensities of presumed vascular origin, with a voxel-based quantitative analysis of (18F)-fluorodesoxyglucose positron emission tomography (FDG-PET) imaging. METHODS: Sixty older hypertensive patients with subjective memory complaints (75 ± 5 years, 34 women) were prospectively referred to FDG-PET and MRI brain imaging. The Statistical Parametric Mapping software was used to assess the correlation between brain distribution of FDG and white-matter hyperintensities assessed by the Fazekas score on MRI images. RESULTS: The Fazekas score was inversely related to FDG uptake, independently of age and gender, within 14 Brodmann areas located mainly in the frontal lobe but also in certain limbic, insular and temporal areas. This relationship was also found to be largely independent of the volume of grey matter expressed in percentage of cranial volume, an index of atrophy. CONCLUSIONS: White-matter MR hyperintensities of presumed vascular origin are cross-sectionally associated with a lower grey-matter metabolism, mainly but not only within frontal areas and independently of age, gender and grey-matter atrophy.


Assuntos
Metabolismo Energético , Substância Cinzenta/diagnóstico por imagem , Hipertensão/complicações , Leucoencefalopatias/diagnóstico por imagem , Imageamento por Ressonância Magnética , Transtornos da Memória/etiologia , Memória , Tomografia por Emissão de Pósitrons , Substância Branca/diagnóstico por imagem , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Fluordesoxiglucose F18/administração & dosagem , Substância Cinzenta/metabolismo , Humanos , Hipertensão/diagnóstico , Leucoencefalopatias/etiologia , Leucoencefalopatias/metabolismo , Masculino , Transtornos da Memória/diagnóstico , Transtornos da Memória/psicologia , Pessoa de Meia-Idade , Projetos Piloto , Valor Preditivo dos Testes , Prognóstico , Compostos Radiofarmacêuticos/administração & dosagem , Fatores de Risco , Substância Branca/metabolismo
4.
Acta Radiol ; 56(8): 980-9, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25085109

RESUMO

BACKGROUND: 18F-FDG PET can be used to aid in the diagnosis of Alzheimer's disease (AD) and clarify the diagnosis and prognosis of patients with mild cognitive impairment (MCI). PURPOSE: To compare the results of a quantitative analysis of FDG-PET brain images to a standard visual analysis (SVA) with regards to the detection of MCI-like hypometabolic pattern in elderly patients with hypertension and subjective, isolated memory complaints. MATERIAL AND METHODS: FDG-PET brain was performed in 71 patients (mean age, 76.4 ± 5.1 years; women, 53.5%). Images were analyzed for the presence of an MCI-like hypometabolic pattern using an SVA by 2 physicians and a voxel-based statistical procedure (statistical parametric mapping [SPM]) that compared each patient's images to normal reference samples from 19 elderly individuals obtained using the same PET camera. The reliability of these analyses was evaluated according to neuropsychological assessment results, including the Grober & Buschke Free and Cued Selective Reminding Test, and a combined analysis by a neuropsychologist. RESULTS: An MCI-like hypometabolic pattern was documented in 5 patients (7%) by SVA and 7 patients (10%) by SPM analysis; however, only 2 of these patients were selected by both methods. The group characteristics of the 7 patients identified by the quantitative method were consistent with the MCI pattern, which included a higher rate of abnormal GB-FCSRT in Free Recall (57% vs. 9%, p < 0.05) or in Total Recall (29% vs. 8%, p < 0.05) when compared with other patients. In contrast, the group identified by SVA did not exhibit these characteristics. CONCLUSION: A combined visual and quantitative analysis improves the diagnostic accuracy to detect an MCI-like hypometabolic pattern in elderly patients with hypertension and subjective, isolated memory complaints.


Assuntos
Encéfalo/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico por imagem , Fluordesoxiglucose F18 , Hipertensão/diagnóstico por imagem , Transtornos da Memória/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Idoso , Feminino , Avaliação Geriátrica/métodos , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Compostos Radiofarmacêuticos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
5.
JAMA ; 314(2): 170-80, 2015 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-26172896

RESUMO

IMPORTANCE: Hypertension treatment is beneficial for most hypertensive patients. The benefits for patients who are very old and frail, especially those taking numerous medications, are less certain. OBJECTIVE: To provide recommendations for the evaluation and treatment of hypertension among patients aged 80 years and older. EVIDENCE ACQUISITION: MEDLINE, PubMed Central, and the Cochrane Database of Systematic Reviews were searched from inception through April 2015, with an emphasis on 2010-2015. Manual cross-referencing of review articles and meta-analyses was also performed to identify randomized controlled trials (RCTs) examining antihypertensive use in octogenarians. The search strategy included the following Medical Subject Headings: hypertension or high blood pressure and trials and oldest old or very old or very elderly. FINDINGS: Six post hoc analyses of the previously published Hypertension in the Very Elderly Trial (HYVET) met the inclusion criteria. In the only placebo-controlled RCT on hypertension management in patients older than 80 years (HYVET; N = 3845), the treatment was associated with lower total mortality and key cardiovascular end points but the effect on stroke (fatal and nonfatal), which was the primary outcome, failed to reach the significance level (P = .06). Post hoc analyses of HYVET suggested that active hypertension treatment in very elderly patients was beneficial by reducing blood pressure in individuals with white coat hypertension, showed moderate benefits of the active treatment for cognition, a possible effect for fractures prevention, and sustained differences in reductions of total mortality and cardiovascular mortality in those receiving active treatment. However, patients were community dwelling and less disabled than individuals of the same age in general. CONCLUSIONS AND RELEVANCE: Hypertensive patients who are healthy, functionally independent, and aged 80 years and older should be treated according to current recommendations for people older than 65 years. There is insufficient evidence regarding the benefits of hypertension treatment for frail polymedicated octogenarians, for whom treatment should be individualized.


Assuntos
Anti-Hipertensivos/uso terapêutico , Hipertensão/tratamento farmacológico , Polimedicação , Fatores Etários , Idoso de 80 Anos ou mais , Pressão Sanguínea/efeitos dos fármacos , Feminino , Idoso Fragilizado , Humanos , Masculino , Guias de Prática Clínica como Assunto , Medicina de Precisão
6.
Food Addit Contam Part B Surveill ; 16(1): 58-68, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36537161

RESUMO

Over the last decade, the consumption of tea and herbal tea has gained more and more popularity across the globe, but the potential presence of chemical contaminants (e.g. pesticides, trace elements, synthetic drugs) may raise health concerns. This study analysed selected teas available in Belgian retail stores and performed a risk assessment for these samples. No chemical adulteration could be detected in dry tea material. More than 38% of the dry leaves samples contained at least one pesticide exceeding the maximal residue level (MRL) set by the EU. However, further risk assessment, based on the values of pesticide residues and the toxic trace elements encountered in the brew, demonstrate that the consumption of these teas will not give rise to health concerns. Nonetheless, attention should be given to the leaching potential of nickel from teas and the presence of arsenic in brews from algae containing teas.


Assuntos
Resíduos de Praguicidas , Praguicidas , Oligoelementos , Praguicidas/análise , Oligoelementos/análise , Chá/química , Bélgica , Contaminação de Alimentos/análise , Resíduos de Praguicidas/análise , Preparações Farmacêuticas/análise
7.
Food Chem ; 429: 136893, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37480773

RESUMO

Pesticide residues in tea and herbal tea often exceed EU maximum residue limits. Consideration of the transfer of pesticides from the leaves (called transfer factors) to the brew is essential to assess the associated risk. This study identified infusion parameters influencing the transfer behaviour of 61 pesticides and elaborated a predictive model for pesticides with unknown transfer factors in black, green, herbal and flavoured teas. Tea type and the presence of flavours were the criteria that most influenced the pesticide transfer. Interestingly, infusion parameters that are individual and area dependent such as infusion time, temperature and water hardness, did not play a significant role. Beta regression models developed to characterise pesticide behaviour during infusion showed good predictions for most pesticides and revealed that log (P) was the main physico-chemical parameter to estimate the pesticide transfer. The transfer factors database and validated models are valuable tools for improving risk assessment.


Assuntos
Resíduos de Praguicidas , Praguicidas , Chás de Ervas , Bases de Dados Factuais , Aromatizantes , Chá
8.
Eur J Hybrid Imaging ; 7(1): 11, 2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37369917

RESUMO

INTRODUCTION: 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) and computed tomography (CT) features of the proximal and more elastic half of the thoracic aorta are known to correlate with aorta stiffness in older populations. This prospective study aimed to analyze the changes in these FDG-PET/CT features between young, middle-aged, and older adults, and investigate associations with arterial stiffness and blood pressure (BP). METHODS: Young (< 40 years), middle-aged (40-to-60 years), and older (> 60 years) adults, who underwent an FDG-PET/CT, were prospectively recruited. FDG-PET/CT features of the proximal half of the thoracic aorta were analyzed relative to the age categories, BP and carotid-femoral pulse wave velocity (PWV), a reference indicator of aorta stiffness. RESULTS: We included 79 patients (38 women; 22 young, 19 middle-aged, and 38 older adults). An increase in age category was associated with increases in mean standardized uptake values (SUVs) of blood and aorta and most significantly in aorta SUV heterogeneity, represented by SUV standard deviation (SUV-SD), aorta calcification volume, and the aorta volume indexed to body surface area. However, this indexed aorta volume was the sole variable: (i) exhibiting a stepwise increase from young (median: 25 cm3/m2 [interquartile range: 20-28 cm3/m2]), to middle-aged (41 [30-48] cm3/m2, p < 0.001 vs. Young), and older (62 [44-70] cm3/m2, p < 0.001 vs. middle-age) adults, and (ii) selected in the multivariate predictions of systolic, diastolic, and pulse BP. Indexed aorta volume was also a multivariate predictor of PWV but in association with SUV-SD and hypertension. CONCLUSION: In a population of patients referred to an FDG-PET/CT investigation, the indexed volume of the proximal and more elastic half of the thoracic aorta is the most comprehensive indicator of arterial aging. This imaging parameter exhibits a stepwise increase from young to middle-aged and older adults, is strongly linked to inter-individual changes in both arterial stiffness and BP, and thus, could help assess the early phases of arterial aging. Trial registration ClinicalTrial.gov, NCT03345290. Registered 17 November 2017, https://clinicaltrials.gov/ct2/show/NCT03345290?term=NCT03345290&draw=2&rank=1.

9.
Environ Sci Pollut Res Int ; 30(23): 64499-64516, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37071363

RESUMO

In spite of the fact that bromophenols (BPs) and hexabromocyclododecanes (HBCDs) are widely used as flame retardants, no data was available until now on the levels of these two chemicals in North Africa biota. Seafood products might represent one of the main sources of dietary exposure to persistent organic pollutants such as non-dioxin-like polychlorinated biphenyls (ndl-PCBs), brominated flame retardants (BFRs), and polycyclic aromatic hydrocarbons (PAHs). In this study, the concentrations of the ndl-PCBs, PAH4, and BFRs were determined in seafood products from a North African lagoon (Bizerte lagoon). Almost all the compounds were detected (15 out of 18) in the analyzed marine organisms. The accumulation of the contaminants followed the order BFRs > ndl-PCB > PAH4. Mean contaminants concentrations ranged from 0.35 to 28.7 ng g-1 ww for ∑ndl-PCBs; from below limit of quantification to 476 ng g-1 ww for ∑BFRs and from below limit of quantification to 5.30 ng g-1 ww for ∑PAH4. PCB 138, 153, and 180 were the most frequently detected ndl-PCB congeners due to their high resistance to metabolic degradation. 2,4-dibromophenol (2,4-DBP) was the predominant BFR. Chrysene (Chr) was found to be the main contributor to the total PAH4 concentration. Contaminant profiles varied significantly among seafood which may be due to the difference in lipid content, trophic level, feeding behavior, and metabolism. To assess the human health risks, the average daily dose exposure of ndl-PCBs, the dietary daily intake of PAHs and the estimated dietary intake of 3,3-,5,5-tetrabromobisphenol A (TBBPA) and HBCD from seafood were estimated. Findings indicated no adverse effects for human health from any of the analyzed contaminants, except for ndl-PCBs in eel.


Assuntos
Dioxinas , Retardadores de Chama , Bifenilos Policlorados , Humanos , Bifenilos Policlorados/análise , Tunísia , Retardadores de Chama/análise , Contaminação de Alimentos/análise , Alimentos Marinhos/análise
10.
Food Addit Contam Part B Surveill ; 15(4): 292-300, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35975751

RESUMO

A total of 120 spices and herbs bought on the Belgian market have been analysed for occurrence of the four EU regulated polycyclic aromatic hydrocarbons (ΣPAH4). Samples were sorted in three groups according to their use: traditional spices, exotic spices, and herbs. Benzo[a]pyrene has been detected in 56% of samples, while ΣPAH4 were found in 96% of samples. ΣPAH4 were evenly distributed among the three groups with a median content of 7.2 for traditional spices, 5.5 for exotic spices and 6.0 µg kg-1 for herbs. According to the EU legislation, three samples were exceeding maximal limits, with a maximum ΣPAH4 content of 164 µg kg-1. The ΣPAH4 dietary intake has been estimated at 1.4 and 27.8 ng day-1 for average and high consumption, respectively. The risk for the consumer was evaluated by using the margin of exposure (MOE). In all cases, MOE were >20 000, indicating a low concern for the population.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Hidrocarbonetos Policíclicos Aromáticos/análise , Especiarias/análise , Contaminação de Alimentos/análise , Bélgica , Benzo(a)pireno/análise
11.
Front Aging Neurosci ; 14: 908063, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35837479

RESUMO

Brain 18F-FDG PET imaging is useful to characterize accelerated brain aging at a pre-symptomatic stage. This study aims to examine the interactions between brain glycolytic metabolism and hemodynamic parameters in different age groups. Methods: A total of 72 patients (from 23 to 88 years of age, 38 women) without any cerebral diseases but with available cardiac, arterial peripheral, and central blood pressure measurements as well as arterial stiffness parameters obtained from brachial pressure and applanation tonometry and a brain 18F-FDG PET scan were prospectively included into this study. Quantitative voxel-to-voxel analyses were carried out to test for negative associations between brain glycolytic metabolism and individual hemodynamic parameters (p-voxel of <0.001 for the whole population and <0.005 for age groups). Results: The heart rate parameter of the whole population showed the most extensive associations with brain metabolism (15,857 mm3, T-score: 5.1), predominantly affecting the frontal and temporal regions (69% of the volume). Heart rate for the younger age group, systolic and pulse pressure for the 41-60-year-old group, and diastolic pressure for the older group were most extensively associated with brain metabolism and mainly involved the fronto-temporal lobes (respective involvement of 52.8%, 60.9%, and 65.5%) which are also the regions implicated in accelerated brain aging. Conclusion: This cross-sectional prospective study identified extensive associations between cerebral metabolism and hemodynamic parameters, indicating common aging mechanisms. Heart rate throughout adult life, systolic and pulse pressure parameters around middle age, and diastolic pressure parameters in older patients, suggest the existence of potentially therapeutic targets to prevent accelerated brain aging.

12.
Environ Pollut ; 291: 118236, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34582924

RESUMO

This study reports on concentrations of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs, respectively) in a wide range of food samples (n = 211) purchased in Belgium during 2020. Samples were analysed by gas chromatography-mass spectrometry (GC-MS) and quantified using chlorine content calibration. ∑SCCPs were present above LOQ in 25% of samples with an overall range of

Assuntos
Hidrocarbonetos Clorados , Parafina , Animais , Bélgica , China , Monitoramento Ambiental , Hidrocarbonetos Clorados/análise , Parafina/análise , Verduras
13.
Phys Chem Chem Phys ; 12(41): 13448-54, 2010 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-20838693

RESUMO

DNA cytosine-rich strands can fold into an intercalated motif (i-motif) structure. The i-motif is formed by mutually intercalated duplexes containing proton-mediated C-H(+)-C (cytosine-proton-cytosine) base pairs. Negatively charged ions of DNA i-motifs produced by electrospray mass spectrometry are therefore zwitterionic if the base pairing motif is preserved in the gas phase. Here we used IRMPD spectroscopy and ion mobility spectrometry to assess whether i-motif structures were preserved in the gas phase. We first investigated the IRMPD spectral signature of the tetramer [dC(6)](4), which can only be formed via C-H(+)-C base pairing, compared to the single strand dC(6). The IR signature of i-motif formation is an apparent broadening of the band at 1650 cm(-1). DFT calculations show this apparent broadening is actually due to blue-shifts of the NH(2) scissoring modes and red shifts of C[double bond, length as m-dash]O stretching modes. We then investigated the gas-phase conformations of the telomeric sequence d(CCCAAT)(3)CCC, that can form an intramolecular i-motif, by performing IRMPD spectroscopy and ion mobility spectrometry as a function of the charge state. We show that the negative ions of the lowest charge states correspond to a preserved i-motif structure. This is the first demonstration of the native extraction of solution-phase zwitterionic nucleic acids using negative electrospray ionization.


Assuntos
DNA/química , Substâncias Intercalantes/química , Íons/química , Pareamento de Bases , Citosina/química , Gases/química , Conformação de Ácido Nucleico , Espectrometria de Massas por Ionização por Electrospray
14.
Hypertension ; 76(3): 629-639, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32755468

RESUMO

The effects of elevated arterial stiffness on cardiovascular outcomes are widely studied, whereas the relation to noncardiovascular outcomes relevant to older persons, such as the effect on bones and muscles, is less well established. Arterial stiffness, bone demineralization, and muscle loss are all age-related processes with common risk factors, however, whether these are just parallel age-related alterations or whether these processes share common pathways is not yet understood. In this review, we outline previous literature using different assessments of arterial stiffness in various populations across the world to produce a comprehensive overview. Although there are many studies showing an association between arterial stiffness and loss of bone and muscle, the majority are cross-sectional and there is limited longitudinal evidence to justify causal conclusions. We also give an in-depth review of hypotheses and possible mechanisms which may underlie these associations including hormone dysregulation, impaired glucose metabolism, and inflammation. This narrative review highlights the associations between vessels, bones, and muscles with aging, offering insights into possible shared pathways.


Assuntos
Envelhecimento/fisiologia , Osteoporose/metabolismo , Sarcopenia , Rigidez Vascular/fisiologia , Fatores de Risco de Doenças Cardíacas , Humanos , Sarcopenia/etiologia , Sarcopenia/metabolismo
15.
Eur J Nucl Med Mol Imaging ; 36(6): 979-85, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19183999

RESUMO

PURPOSE: To analyse the relationship between: (i) aortic pulse wave velocity (PWV), an index of aortic stiffness with strong prognostic significance, and (ii) aortic calcification and inflammation, which were quantified by hybrid imaging with X-ray computed tomography (CT) and (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET). METHODS: Central aortic (carotid-femoral) and peripheral (carotid-brachial and femoral-tibial) PWV were recorded in 26 patients, who had been routinely referred for dual FDG-PET/CT imaging. RESULTS: In univariate analyses, central aortic PWV was strongly linked to the volume of calcifications (VCa) and an enhanced FDG activity, when determined by averaging standardized uptake values (SUV(max)). By multivariate stepwise analysis including age and gender, both VCa (p < 0.0001) and SUV(max) (p < 0.01) were significant determinants of PWV explaining 61% and 11% of its variability. CONCLUSION: Aortic inflammation, assessed by hybrid FDG-PET/CT imaging, is associated with an enhanced aortic stiffness, in addition to the concurrent impact of calcifications.


Assuntos
Aorta/patologia , Aorta/fisiopatologia , Calcinose/complicações , Calcinose/fisiopatologia , Fluordesoxiglucose F18 , Inflamação/complicações , Inflamação/fisiopatologia , Aorta/diagnóstico por imagem , Aortografia , Calcinose/diagnóstico por imagem , Feminino , Hemodinâmica , Humanos , Inflamação/diagnóstico , Pessoa de Meia-Idade , Projetos Piloto , Tomografia por Emissão de Pósitrons , Tomografia Computadorizada por Raios X
16.
J Phys Chem B ; 113(32): 11293-300, 2009 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-19621911

RESUMO

We present a joint experimental and theoretical investigation of the structural and optical properties of copper-oxytocin dications in the gas phase. Ion mobility and UV photodissociation experiments were performed, allowing the investigation of the influence of the Cu(2+) ion on the structural and optical properties of oxytocin. Density functional theory calculations were performed to find low energy structures for the bare and complexed peptide and to characterize optical spectral features. Copper complexation induces a drastic change in the structure of the oxytocin peptide. In particular, we predict a 4N chelation of the copper cation which leads to a contraction of the oxytocin ring. The gas phase lowest-energy structures are compared with the X-ray crystal structure of the oxytocin molecule bound to its receptor protein. The optical spectrum of oxytocin complexed with the copper cation displays a global enhancement of the photofragmentation yield as compared to the one recorded for the doubly protonated oxytocin. Moreover, experimental and calculated optical spectra of protonated tyrosine have also been determined, since its leading features are present in oxytocin as well.


Assuntos
Cátions Bivalentes , Cobre/química , Gases , Ocitocina/química , Cristalografia por Raios X , Estrutura Molecular
17.
J Phys Chem A ; 113(24): 6607-11, 2009 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-19459666

RESUMO

Trapped oxytocin (OT) peptide dianions and copper-oxytocin complex dianions are subjected to electron detachment when irradiated by a UV light. Electron photodetachment experiments as a function of the laser wavelength were performed on the native disulfide-containing ring oxytocin, the reduced dithiol oxytocin, and the Cu(II)-oxytocin complex. The electron detachment yield was used to monitor the excited electronic spectrum of the trapped ions. The spectra can be used as a fingerprint of the ionization state of the tyrosine chromophore under different structural environments. In gas-phase oxytocin dianion [OT-2H](2-), the tyrosine is deprotonated while it is neutral for the reduced form of oxytocin [OT(SH)-2H](2-). Optical spectra for the copper complex dianion [OT-4H+Cu](2-) are in favor of a neutral tyrosine in the complex. A structure with the metal cation chelated to four deprotonated amide groups is proposed for this complex.


Assuntos
Cobre/química , Compostos Organometálicos/química , Ocitocina/química , Ânions/química , Estrutura Molecular , Raios Ultravioleta
19.
J Am Chem Soc ; 130(42): 13832-3, 2008 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-18817390

RESUMO

A doubly deprotonated tryptophan containing peptide was electrosprayed and isolated in an ion trap. UV excitation on this peptide leads to electron detachment and to the formation of an indolyl radical. The photogenerated radical was fragmented by a second laser. The visible spectrum of the gas-phase neutral tryptophan radical containing peptide has been recorded and constitutes a benchmark for calculations and optical measurements.


Assuntos
Espectrometria de Massas/métodos , Oligopeptídeos/química , Triptofano/química , Valina/química , Radicais Livres/química , Radicais Livres/efeitos da radiação , Gases/química , Gases/efeitos da radiação , Luz , Estrutura Molecular , Oligopeptídeos/efeitos da radiação , Triptofano/efeitos da radiação , Raios Ultravioleta , Valina/efeitos da radiação
20.
J Am Chem Soc ; 130(47): 15903-6, 2008 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-18975871

RESUMO

We present the first photoelectron (PE) spectra of polypeptide polyanions. Combining PE spectroscopy and mass spectrometry provides a direct measurement of the stability of the polyanions with respect to electron detachment and of the repulsive energy between excess charges. The second electron affinity of gramicidin was found to amount to 2.35 +/- 0.15 eV, and the value of the repulsive Coulomb barrier was estimated to be 0.5 +/- 0.15 eV. The spectra are interpreted as resulting from a competition between delayed and direct emission.


Assuntos
Elétrons , Gramicidina/química , Polímeros/química , Bacillus/química , Cinética , Modelos Moleculares , Conformação Molecular , Polieletrólitos , Análise Espectral
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