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1.
Diagnostics (Basel) ; 11(3)2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33808904

RESUMO

Discriminating between cardiac and pulmonary dyspnea is essential for patients' management. We investigated the feasibility and ability of forced oscillation techniques (FOT) in distinguishing between acute exacerbation of COPD (AECOPD), and acute decompensated heart failure (ADHF) in a clinical emergency setting. We enrolled 49 patients admitted to the emergency department (ED) for dyspnea and acute respiratory failure for AECOPD, or ADHF, and 11 healthy subjects. All patients were able to perform bedside FOT measurement. Patients with AECOPD showed a significantly higher inspiratory resistance at 5 Hz, Xrs5 (179% of predicted, interquartile range, IQR 94-224 vs. 100 IQR 67-149; p = 0.019), and a higher inspiratory reactance at 5 Hz (151%, IQR 74-231 vs. 57 IQR 49-99; p = 0.005) than patients with ADHF. Moreover, AECOPD showed higher heterogeneity of ventilation (respiratory system resistance difference at 5 and 19 Hz, Rrs5-19: 1.49 cmH2O/(L/s), IQR 1.03-2.16 vs. 0.44 IQR 0.22-0.76; p = 0.030), and a higher percentage of flow limited breaths compared to ADHF (10%, IQR 0-100 vs. 0 IQR 0-12; p = 0.030). FOT, which resulted in a suitable tool to be used in the ED setting, has the ability to identify distinct mechanical properties of the respiratory system in AECOPD and ADHF.

2.
Insects ; 12(4)2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33923404

RESUMO

Lebambromyia sacculifera sp. nov. is described from Late Cretaceous amber from Myanmar, integrating traditional observation techniques and X-ray phase contrast microtomography. Lebambromyia sacculifera is the second species of Lebambromyia after L. acrai Grimaldi and Cumming, described from Lebanese amber (Early Cretaceous), and the first record of this taxon from Myanmar amber, considerably extending the temporal and geographic range of this genus. The new specimen bears a previously undetected set of phylogenetically relevant characters such as a postpedicel sacculus and a prominent clypeus, which are shared with Ironomyiidae and Eumuscomorpha. Our cladistic analyses confirmed that Lebambromyia represented a distinct monophyletic lineage related to Platypezidae and Ironomyiidae, though its affinities are strongly influenced by the interpretation and coding of the enigmatic set of features characterizing these fossil flies.

5.
J Struct Biol ; 212(3): 107659, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33152420

RESUMO

Pineal gland (PG) is a part of the human brain epithalamus that plays an important role in sleep, circadian rhythm, immunity, and reproduction. The calcium deposits and lesions in PG interfere with normal function of the organ and can be associated with different health disorders including serious neurological diseases. At the moment, the detailed mechanisms of PG calcifications and PG lesions formation as well as their involvement in pathological processes are not fully understood. The deep and comprehensive study of the structure of the uncut human PG with histological details, poses a stiff challenge to most imaging techniques, due to low spatial resolution, low visibility or to exceedingly aggressive sample preparation. Here, we investigate the whole uncut and unstained human post-mortem PGs by X-ray phase contrast tomography (XPCT). XPCT is an advanced 3D imaging technique, that permits to study of both soft and calcified tissue of a sample at different scales: from the whole organ to cell structure. In our research we simultaneously resolved 3D structure of parenchyma, vascular network and calcifications. Moreover, we distinguished structural details of intact and degenerated PG tissue. We discriminated calcifications with different structure, pinealocytes nuclei and the glial cells processes. All results were validated by histology. Our research clear demonstrated that XPCT is a potential tool for the high resolution 3D imaging of PG morphological features. This technique opens a new perspective to investigate PG dysfunction and understand the mechanisms of onset and progression of diseases involving the pineal gland.


Assuntos
Calcinose/patologia , Glândula Pineal/patologia , Idoso , Encéfalo/patologia , Feminino , Humanos , Imageamento Tridimensional/métodos , Masculino , Microscopia de Contraste de Fase/métodos , Pessoa de Meia-Idade , Tomografia por Raios X , Raios X
6.
Front Neurosci ; 14: 584161, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33240038

RESUMO

We report a qualitative study on central nervous system (CNS) damage that demonstrates the ability of X-ray phase contrast tomography (XPCT) to confirm data obtained with standard 2D methodology and permits the description of additional features that are not detected with 2D or other 3D techniques. In contrast to magnetic resonance or computed tomography, XPCT makes possible the high-resolution 3D imaging of soft tissues classically considered "invisible" to X-rays without the use of additional contrast agents, or without the need for intense processing of the tissue required by 2D techniques. Most importantly for studies of CNS diseases, XPCT enables a concomitant multi-scale 3D biomedical imaging of neuronal and vascular networks ranging from cells through to the CNS as a whole. In the last years, we have used XPCT to investigate neurodegenerative diseases, such as Alzheimer's disease (AD) and multiple sclerosis (MS), to shed light on brain damage and extend the observations obtained with standard techniques. Here, we show the cutting-edge ability of XPCT to highlight in 3D, concomitantly, vascular occlusions and damages, close associations between plaques and damaged vessels, as well as dramatic changes induced at neuropathological level by treatment in AD mice. We corroborate data on the well-known blood-brain barrier dysfunction in the animal model of MS, experimental autoimmune encephalomyelitis, and further show its extent throughout the CNS axis and at the level of the single vessel/capillary.

7.
Sci Rep ; 10(1): 11233, 2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32641715

RESUMO

Visualization and characterization of [Formula: see text]-amyloid deposits is a fundamental task in pre-clinical study of Alzheimer's disease (AD) to assess its evolution and monitor the efficiency of new therapeutic strategies. While the cerebellum is one of the brain areas most underestimated in the context of AD, renewed interest in cerebellar lesions has recently arisen as they may link to motor and cognitive alterations. Thus, we quantitatively investigated three-dimensional plaque morphology in the cerebellum in APP/PS1 transgenic mouse, as a model of AD. In order to obtain a complete high-resolution three-dimensional view of the investigated tissue, we exploited synchrotron X-ray phase contrast tomography (XPCT), providing virtual slices with histology-matching resolution. We found the formation of plaques elongated in shape, and with a specific orientation in space depending on the investigated region of the cerebellar cortex. Remarkably, a similar shape is observed in human cerebellum from demented patients. Our findings demonstrate the capability of XPCT in volumetric quantification, supporting the current knowledge about plaque morphology in the cerebellum and the fundamental role of the surrounding tissue in driving their evolution. A good correlation with the human neuropathology is also reported.


Assuntos
Doença de Alzheimer/diagnóstico , Córtex Cerebelar/patologia , Imageamento Tridimensional , Placa Amiloide/diagnóstico , Idoso de 80 Anos ou mais , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Precursor de Proteína beta-Amiloide/genética , Animais , Córtex Cerebelar/diagnóstico por imagem , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Placa Amiloide/genética , Placa Amiloide/patologia , Presenilina-1/genética , Radiografia , Síncrotrons , Tomografia Computadorizada por Raios X/instrumentação , Tomografia Computadorizada por Raios X/métodos
8.
Front Neurosci ; 14: 72, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32116518

RESUMO

Non-invasive imaging methods have become essential tools for understanding the central nervous system (CNS) in health and disease. In particular, magnetic resonance imaging (MRI) techniques provide information about the anatomy, microstructure, and function of the brain and spinal cord in vivo non-invasively. However, MRI is limited by its spatial resolution and signal specificity. In order to mitigate these shortcomings, it is crucial to validate MRI with an array of ancillary ex vivo imaging techniques. These techniques include histological methods, such as light and electron microscopy (EM), which can provide specific information on the tissue structure in healthy and diseased brain and spinal cord, at cellular and subcellular level. However, these conventional histological techniques are intrinsically two-dimensional (2D) and, as a result of sectioning, lack volumetric information of the tissue. This limitation can be overcome with genuine three-dimensional (3D) imaging approaches of the tissue. 3D highly resolved information of the CNS achievable by means of other imaging techniques can complement and improve the interpretation of MRI measurements. In this article, we provide an overview of different 3D imaging techniques that can be used to validate MRI. As an example, we introduce an approach of how to combine diffusion MRI and synchrotron X-ray phase contrast tomography (SXRPCT) data. Our approach paves the way for a new multiscale assessment of the CNS allowing to validate and to improve our understanding of in vivo imaging (such as MRI).

9.
J Synchrotron Radiat ; 27(Pt 4): 1042-1048, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33566014

RESUMO

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting motor neurons. Pre-clinical studies drive the development of animal models that well mimic ALS disorder and enable both the dissection of disease processes and an early assessment of therapy efficacy. A comprehensive knowledge of neuronal and vascular lesions in the brain and spinal cord is an essential factor to understand the development of the disease. Spatial resolution and bidimensional imaging are important drawbacks limiting current neuroimaging tools, while neuropathology relies on protocols that may alter tissue chemistry and structure. In contrast, recent ex vivo studies in mice demonstrated that X-ray phase-contrast tomography enables study of the 3D distribution of both vasculature and neuronal networks, without sample sectioning or use of staining. Here we present our findings on ex vivo SOD1G93A ALS mice spinal cord at a micrometric scale. An unprecedented direct quantification of neuro-vascular alterations at different stages of the disease is shown.


Assuntos
Esclerose Amiotrófica Lateral/diagnóstico por imagem , Medula Espinal/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Animais , Modelos Animais de Doenças , Imageamento Tridimensional , Camundongos , Camundongos Transgênicos , Sensibilidade e Especificidade , Razão Sinal-Ruído
10.
Int J Numer Method Biomed Eng ; 36(2): e3290, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31808299

RESUMO

Since the introduction of functional magnetic resonance imaging (fMRI), several computational approaches have been developed to examine the effect of the morphology and arrangement of blood vessels on the blood oxygenation-level dependent (BOLD) signal in the brain. In the present work, we implemented the original Ogawa's model using a numerical simulation based on the finite element method (FEM) instead of the analytical models. In literature, there are different works using analytical methods to analyse the transverse relaxation rate ( R 2 ∗ ), which BOLD signal is related to, modelling the vascular system with simple and canonical geometries such as an infinite cylinder model (ICM) or a set of cylinders. We applied the numerical simulation to the extravascular BOLD signal as a function of angular vessel distribution (perpendicular vs parallel to the static magnetic field) relevant for anatomical districts characterized by geometrical symmetries, such as spinal cord. Numerical simulations confirmed analytical results for the canonical ICM. Moreover, the perturbation to the magnetic field induced by blood deoxyhaemoglobin, as quantified assuming Brownian diffusion of water molecules around the vessel, revealed that vessels contribute the most to the variation of the R 2 ∗ when they are preferentially perpendicular to the external magnetic field, regardless of their size. Our results indicate that the numerical simulation method is sensitive to the effects of different vascular geometry. This work highlights the opportunity to extend R 2 ∗ simulations to realistic models of vasculature based on high-resolution anatomical images.


Assuntos
Análise de Elementos Finitos , Imageamento por Ressonância Magnética/métodos , Simulação por Computador , Humanos , Modelos Teóricos , Oxigênio/análise , Água/análise
11.
Front Neurosci ; 13: 965, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31619948

RESUMO

Phasic changes in eye's pupil diameter have been repeatedly observed during cognitive, emotional and behavioral activity in mammals. Although pupil diameter is known to be associated with noradrenergic firing in the pontine Locus Coeruleus (LC), thus far the causal chain coupling spontaneous pupil dynamics to specific cortical brain networks remains unknown. In the present study, we acquired steady-state blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) data combined with eye-tracking pupillometry from fifteen healthy subjects that were trained to maintain a constant attentional load. Regression analysis revealed widespread visual and sensorimotor BOLD-fMRI deactivations correlated with pupil diameter. Furthermore, we found BOLD-fMRI activations correlated with pupil diameter change rate within a set of brain regions known to be implicated in selective attention, salience, error-detection and decision-making. These regions included LC, thalamus, posterior cingulate cortex (PCC), dorsal anterior cingulate and paracingulate cortex (dACC/PaCC), orbitofrontal cortex (OFC), and right anterior insular cortex (rAIC). Granger-causality analysis performed on these regions yielded a complex pattern of interdependence, wherein LC and pupil dynamics were far apart in the network and separated by several cortical stages. Functional connectivity (FC) analysis revealed the ubiquitous presence of the superior frontal gyrus (SFG) in the networks identified by the brain regions correlated to the pupil diameter change rate. No significant correlations were observed between pupil dynamics, regional activation and behavioral performance. Based on the involved brain regions, we speculate that pupil dynamics reflects brain processing implicated in changes between self- and environment-directed awareness.

12.
Neuroimage ; 184: 490-495, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30240904

RESUMO

Alzheimer's disease (AD), the most common form of dementia, is a progressive neurodegenerative disorder associated with aberrant production of beta-amyloid (Aß) peptide depositing in brain as amyloid plaques. While animal models allow investigation of disease progression and therapeutic efficacy, technology to fully dissect the pathological mechanisms of this complex disease at cellular and vascular levels is lacking. X-ray phase contrast tomography (XPCT) is an advanced non-destructive 3D multi-scale direct imaging from the cell through to the whole brain, with exceptional spatial and contrast resolution. We exploit XPCT to simultaneously analyse disease-relevant vascular and neuronal networks in AD mouse brain, without sectioning and staining. The findings clearly show the different typologies and internal structures of Aß plaques, together with their interaction with patho/physiological cellular and neuro-vascular microenvironment. XPCT enables for the first time a detailed visualization of amyloid-angiopathy at capillary level, which is impossible to achieve with other approaches. XPCT emerges as added-value technology to explore AD mouse brain as a whole, preserving tissue chemistry and structure, enabling the comparison of physiological vs. pathological states at the level of crucial disease targets. In-vivo translation will permit to monitor emerging therapeutic approaches and possibly shed new light on pathological mechanisms of neurodegenerative diseases.


Assuntos
Doença de Alzheimer/patologia , Encéfalo/patologia , Imageamento Tridimensional/métodos , Neuroimagem/métodos , Tomografia Computadorizada por Raios X/métodos , Animais , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Transgênicos
13.
Biochim Biophys Acta Gen Subj ; 1861(6): 1486-1493, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28011302

RESUMO

One of the more intriguing aspects of carbohydrate chemistry is that despite having very similar molecular structures, sugars have very different properties. For instance, there is a sensible difference in sweet taste between glucose and trehalose, even though trehalose is a disaccharide that comprised two glucose units, suggesting a different ability of these two carbohydrates to bind to sweet receptors. Here we have looked at the hydration of specific sites and at the three-dimensional configuration of water molecules around three carbohydrates (glucose, cellobiose, and trehalose), combining neutron diffraction data with computer modelling. Results indicate that identical chemical groups can have radically different hydration patterns depending on their location on a given molecule. These differences can be linked with the specific activity of glucose, cellobiose, and trehalose as a sweet substance, as building block of cellulose fiber, and as a bioprotective agent, respectively. This article is part of a Special Issue entitled "Recent Advances in Bionanomaterials" Guest Editors: Dr. Marie-Louise Saboungi and Dr. Samuel D. Bader.


Assuntos
Celobiose/química , Glucose/química , Paladar , Trealose/química , Água/química , Configuração de Carboidratos , Celobiose/metabolismo , Glucose/metabolismo , Humanos , Ligantes , Modelos Químicos , Simulação de Acoplamento Molecular , Difração de Nêutrons , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais , Relação Estrutura-Atividade , Percepção Gustatória , Trealose/metabolismo
14.
Rays ; 29(4): 465-8, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15852738

RESUMO

Postoperative complications and related risk factors after lung reduction surgery are analyzed based on a review of the literature. In particular the pathogenesis of some of postoperative respiratory disorders is carefully assessed. Most commonly cardiac arrhythmias, respiratory failure, bronchopleural fistula are observed. Main risk factors for postoperative complications are old age, chronic obstructive pulmonary disease, coronary disease, poor nutritional state, neoadjuvant therapy. Attention should be paid to all these factors, both in preoperative assessment and postoperative care, to prevent and promptly treat postoperative complications.


Assuntos
Neoplasias Pulmonares/cirurgia , Complicações Pós-Operatórias , Procedimentos Cirúrgicos Torácicos , Humanos , Fatores de Risco
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