Quantitative characterization of amyloid deposits in murine models of alzheimer disease by phase-contrast x-ray imaging

Alzheimer's is a neurodegenerative disease that is the most common form of dementia, but there is still no definitive cure for this disease. The noninvasive X-ray Phase Contrast Tomography (XPCT) imaging technique was used to study brain tissues in mouse models of Alzheimer's disease, AP-PS1 and APP23. The XPCT technique enabled high-resolution imaging of brain tissues, distinguishing between different brain structures, such as amyloid deposits and neuronal cells. In addition, the XPCT technique provided detailed information on the distribution and morphology of amyloid deposits in AP-PS1 and APP23 mice putting in evidence the differences between these two models. This work demonstrates the effectiveness of this technique in supporting Alzheimer's studies and evaluating new therapeutic strategies.Comment: 14 pages, 8 figure

Discovery of Lebambromyia in Myanmar cretaceous amber: phylogenetic and biogeographic implications (Insecta, Diptera, Phoroidea)

Lebambromyia sacculifera sp. nov. is described from Late Cretaceous amber from Myan-mar, 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

Some morphological factors of resistance of the bronchial wall to the development of chronic obstructive lung disease in smoking individuals

According to current epidemiological studies, chronic obstructive pulmonary disease (COPD) develops in only 15-20 % of smokers. This suggests that exposure to tobacco smoke is just a trigger of the pathological process, and other pathophysiological factors play a key role in the development of COPD. The aim of the study was to perform morphological analysis of bronchial mucosa features in smokers with and without chronic obstructive pulmonary disease.Material and research methods. Morphological and electron-microscopic analysis of biopsy samples of the bronchial mucosa of smoking patients with (n = 40) and without (n = 30) chronic obstructive pulmonary disease was carried out. The study involved men (80.2 % of men) and women aged 42 to 67 years (62.3 ± 2.24 years) with smoking experience of more than 20 years and smoking intensity of 20-45 pack-years. In the main group was a verified diagnosis of COPD. All patients of the studied groups underwent morphological, morphometric counting of bulk densities of various types of epithelial cells and structures of their lamina propria of the bronchial mucosa, as well as the density of inflammatory infiltrate and various cell populations, immunohistochemical (typing of CD4- and CD8positive lymphocytes, expression of transforming growth factor β1 receptors) and electron microscopic analysis of bronchobioptates.Results and discussion. Smokers without chronic obstructive pulmonary disease develop exudative inflammation, which does not violate the structural architectonics of the epithelial layer, but causes activation of proteinsynthetic and energy processes in the epithelial cells of the bronchial wall. With prolonged exposure to tobacco smoke associated with the development of chronic obstructive pulmonary disease, chronic neutrophilic inflammation forms in the bronchial mucosa, leading to a violation of the functional morphology of the vessels and epithelial cells of the bronchial mucosa, followed by remodeling of the bronchial wall

3D imaging of theranostic nanoparticles in mice organs by means of x-ray phase contrast tomography

Theranostics is an innovative research field that aims to develop high target specificity cancer treatments by administering small metal-based nanoparticles (NPs). This new generation of compounds exhibits diagnostic and therapeutic properties due to the high atomic number of their metal component. In the framework of a combined research program on low dose X-ray imaging and theranostic NPs, X-ray Phase Contrast Tomography (XPCT) was performed at ESRF using a 3 \u3bcm pixel optical system on two samples: a mouse brain bearing melanoma metastases injected with gadolinium NPs and, a mouse liver injected with gold NPs. XPCT is a non-destructive technique suitable to achieve the 3D reconstruction of a specimen and, widely used at micro-scale to detect abnormalities of the vessels, which are associated to the tumor growth or to the development of neurodegenerative diseases. Moreover, XPCT represents a promising and complementary tool to study the biodistribution of theranostic NPs in biological materials, thanks to the strong contrast with respect to soft tissues that metal-based NPs provide in radiological images. This work is relied on an original imaging approach based on the evaluation of the contrast differences between the images acquired below and above K-edge energies, as a proof of the certain localization of NPs. We will present different methods aiming to enhance the localization of NPs and a 3D map of their distribution in large volume of tissues

High resolution 3D visualization of the spinal cord in a post-mortem murine model

A crucial issue in the development of therapies to treat pathologies of the central nervous system is represented by the availability of non-invasive methods to study the three-dimensional morphology of spinal cord, with a resolution able to characterize its complex vascular and neuronal organization. X-ray phase contrast micro-tomography enables a high-quality, 3D visualization of both the vascular and neuronal network simultaneously without the need of contrast agents, destructive sample preparations or sectioning. Until now, high resolution investigations of the post-mortem spinal cord in murine models have mostly been performed in spinal cords removed from the spinal canal. We present here post-mortem phase contrast micro-tomography images reconstructed using advanced computational tools to obtain high-resolution and high-contrast 3D images of the fixed spinal cord without removing the bones and preserving the richness of micro-details available when measuring exposed spinal cords. We believe that it represents a significant step toward the in-vivo application

Ancient Greek text concealed on the back of unrolled papyrus revealed through Shortwave-Infrared Hyperspectral Imaging

Only a few Herculaneum rolls exhibit writing on their reverse side. Since unrolled papyri are permanently glued to paperboard, so far, this fact was known to us only from 18th-century drawings. The application of shortwave-infrared (SWIR; 1000-2500 nm) hyperspectral imaging (HSI) to one of them (PHerc. 1691/1021) has revealed portions of Greek text hidden on the back more than 220 years after their first discovery, making it possible to recover this primary source for the ongoing new edition of this precious book. SWIR HSI has produced better contrast and legibility even on the extensive text preserved on the front compared to former imaging of Herculaneum papyri at 950 nm (improperly called multispectral imaging), with a substantial impact on the text reconstruction. These promising results confirm the importance of advanced techniques applied to ancient carbonized papyri and open the way to a better investigation of hundreds of other such papyri

Assessment of the effects of different sample perfusion procedures on phase-contrast tomographic images of mouse spinal cord

Synchrotron X-ray Phase Contrast micro-Tomography (SXrPC\u3bcT) is a powerful tool in the investigation of biological tissues, including the central nervous system (CNS), and it allows to simultaneously detect the vascular and neuronal network avoiding contrast agents or destructive sample preparations. However, specific sample preparation procedures aimed to optimize the achievable contrast- and signal-to-noise ratio (CNR and SNR, respectively) are required. Here we report and discuss the effects of perfusion with two different fixative agents (ethanol and paraformaldehyde) and with a widely used contrast medium (MICROFIL\uae) on mouse spinal cord. As a main result, we found that ethanol enhances contrast at the grey/white matter interface and increases the contrast in correspondence of vascular features and fibres, thus providing an adequate spatial resolution to visualise the vascular network at the microscale. On the other hand, ethanol is known to induce tissue dehydration, likely reducing cell dimensions below the spatial resolution limit imposed by the experimental technique. Nonetheless, neurons remain well visible using either perfused paraformaldehyde or MICROFIL\uae compound, as these latter media do not affect tissues with dehydration effects. Paraformaldehyde appears as the best compromise: it is not a contrast agent, like MICROFIL\uae, but it is less invasive than ethanol and permits to visualise well both cells and blood vessels. However, a quantitative estimation of the relative grey matter volume of each sample has led us to conclude that no significant alterations in the grey matter extension compared to the white matter occur as a consequence of the perfusion procedures tested in this study