Protocol for 3D virtual histology of unstained human brain tissue using synchrotron radiation phase-contrast microtomography

X-ray phase-contrast micro computed tomography using synchrotron radiation (SR PhC-μCT) offers unique 3D imaging capabilities for visualizing microstructure of the human brain. Its applicability for unstained soft tissue is an area of active research. Acquiring images from a tissue block without needing to section it into thin slices, as required in routine histology, allows for investigating the microstructure in its natural 3D space. This paper presents a detailed step-bystep guideline for imaging unstained human brain tissue at resolutions of a few micrometers with SR PhC-μCT implemented at SYRMEP, the hard X-ray imaging beamline of Elettra, the Italian synchrotron facility. We present examples of how blood vessels and neurons appear in the images acquired with isotropic 5 μm and 1 μm voxel sizes. Furthermore, the proposed protocol can be used to investigate important biological substrates such as neuromelanin or corpora amylacea. Their spatial distribution can be studied using specifically tailored segmentation tools that are validated by classical histology methods. In conclusion, SR PhC-μCT using the proposed protocols, including data acquisition and image processing, offers viable means of obtaining information about the anatomy of the human brain at the cellular level in 3D

Distribution of corpora amylacea in the human midbrain: using synchrotron radiation phase-contrast microtomography, high-field magnetic resonance imaging, and histology

Corpora amylacea (CA) are polyglucosan aggregated granules that accumulate in the human body throughout aging. In the cerebrum, CA have been found in proximity to ventricular walls, pial surfaces, and blood vessels. However, studies showing their three-dimensional spatial distribution are sparse. In this study, volumetric images of four human brain stems were obtained with MRI and phase-contrast X-ray microtomography, followed up by Periodic acid Schiff stain for validation. CA appeared as hyperintense spheroid structures with diameters up to 30μm. An automatic pipeline was developed to segment the CA, and the spatial distribution of over 200,000 individual corpora amylacea could be investigated. A threefold—or higher—density of CA was detected in the dorsomedial column of the periaqueductal gray (860–4,200 CA count/mm3) than in the superior colliculus (150–340 CA count/mm3). We estimated that about 2% of the CA were located in the immediate vicinity of the vessels or in the peri-vascular space. While CA in the ependymal lining of the cerebral aqueduct was rare, the sub-pial tissue of the anterior and posterior midbrain contained several CA. In the sample with the highest CA density, quantitative maps obtained with MRI revealed high R2∗ values and a diamagnetic shift in a region which spatially coincided with the CA dense region

Clinical study in phase- contrast mammography: image-quality analysis

The first clinical study of phase-contrast mammography (PCM) with synchrotron radiation was carried out at the Synchrotron Radiation for Medical Physics beamline of the Elettra synchrotron radiation facility in Trieste (Italy) in 2006–2009. The study involved 71 patients with unresolved breast abnormalities after conventional digital mammography and ultrasonography exams carried out at the Radiology Department of Trieste University Hospital. These cases were referred for mammography at the synchrotron radiation facility, with images acquired using a propagation-based phase-contrast imaging technique. To investigate the contribution of phase-contrast effects to the image quality, two experienced radiologists specialized in mammography assessed the visibility of breast abnormalities and of breast glandular structures. The images acquired at the hospital and at the synchrotron radiation facility were compared and graded according to a relative seven-grade visual scoring system. The statistical analysis highlighted that PCM with synchrotron radiation depicts normal structures and abnormal findings with higher image quality with respect to conventional digital mammography

Infraestructura verde y envejecimiento en la ciudad de Córdoba desde la perspectiva de los ODS

Population ageing is one of the most significant demographic phenomenon of the 21st century. Many studies have reported that exposure to Green Spaces (GS) has been associated with various health outcomes, especially for older adults wellbeing and dignity in old age. GS also offer a space for performing daily activities nearby their residential environment, and provide a multi-course space for recreation, learning and socialization. The objective of the present study is to provide reliable and practical tools needed to formulate adaptable urban policies that meet the needs of older adults and the GS management in the city of Cordoba. This work is aligned with the search for initiatives that guarantee the access to institutions, services or areas of recreation, leisure and personal development for older adults, in accordance with the provisions of Sustainable Development Goals number 10 and 11. Different demographic indices and indicators associated with aging and GS location were used, which were imported into a geographic information system for their subsequent spatial characterization and construction of distribution maps. Among other indicators, the older adult population without access to GS was estimated. It was observed that the distribution of older adults is heterogeneous, with a segregation index of 0.23. Additionally, 28% of the older adult population does not have a green space within 300 meters.El envejecimiento poblacional representa uno de los fenómenos demográficos más característicos de nuestra era. Los Espacios Verdes (EV) cumplen un rol fundamental en la dignificación de vejez, brindando un espacio pluriconcurrido de esparcimiento, aprendizaje y socialización. El objetivo del presente trabajo es aportar herramientas para formular políticas urbanas adaptables a las necesidades de los adultos mayores y la gestión de EV en la ciudad de Córdoba. Se busca aportar lineamientos para el acceso a instituciones, servicios o áreas de esparcimiento, ocio y desarrollo para una vejez digna, en concordancia a lo planteado en los Objetivos de Desarrollo Sostenible número 10 y 11. Se utilizaron diferentes índices e indicadores demográficos asociados al envejecimiento y localización de EV, los cuales fueron importados a un sistema de información geográfico para su posterior caracterización espacial y construcción de mapas de distribución. Se estimó, entre otros indicadores, la población adulta mayor sin acceso a EV. Se observó que la distribución de las personas adultas mayores es heterogénea, con un índice de segregación de 0,23. Adicionalmente, el 28% de la población adulta mayor no tiene un espacio verde a menos de 300 metros

Novel setup for rapid phase contrast CT imaging of heavy and bulky specimens

This work introduces a novel setup for computed tomography of heavy and bulky specimens at the SYRMEP beamline of the Italian synchrotron Elettra. All the key features of the setup are described and the first application to offcenter computed tomography scanning of a human chest phantom (approximately 45 kg) as well as the first results for vertical helical acquisitions are discussed

Characterization of the insulin sensitivity of ghrelin receptor KO mice using glycemic clamps

<p>Abstract</p> <p>Background</p> <p>We and others have demonstrated previously that ghrelin receptor (<it>GhrR</it>) knock out (KO) mice fed a high fat diet (HFD) have increased insulin sensitivity and metabolic flexibility relative to WT littermates. A striking feature of the HFD-fed <it>GhrR </it>KO mouse is the dramatic decrease in hepatic steatosis. To characterize further the underlying mechanisms of glucose homeostasis in <it>GhrR </it>KO mice, we conducted both hyperglycemic (HG) and hyperinsulinemic-euglycemic (HI-E) clamps. Additionally, we investigated tissue glucose uptake and specifically examined liver insulin sensitivity.</p> <p>Results</p> <p>Consistent with glucose tolerance-test data, in HG clamp experiments, <it>GhrR </it>KO mice showed a reduction in glucose-stimulated insulin release relative to WT littermates. Nevertheless, a robust 1^stphase insulin secretion was still achieved, indicating that a healthy β-cell response is maintained. Additionally, <it>GhrR </it>KO mice demonstrated both a significantly increased glucose infusion rate and significantly reduced insulin requirement for maintenance of the HG clamp, consistent with their relative insulin sensitivity. In HI-E clamps, both LFD-fed and HFD-fed <it>GhrR </it>KO mice showed higher peripheral insulin sensitivity relative to WT littermates as indicated by a significant increase in insulin-stimulated glucose disposal (Rd), and decreased hepatic glucose production (HGP). HFD-fed <it>GhrR </it>KO mice showed a marked increase in peripheral tissue glucose uptake in a variety of tissues, including skeletal muscle, brown adipose tissue and white adipose tissue. <it>GhrR </it>KO mice fed a HFD also showed a modest, but significant decrease in conversion of pyruvate to glucose, as would be anticipated if these mice displayed increased liver insulin sensitivity. Additionally, the levels of UCP2 and UCP1 were reduced in the liver and BAT, respectively, in <it>GhrR </it>KO mice relative to WT mice.</p> <p>Conclusions</p> <p>These results indicate that improved glucose homeostasis of <it>GhrR </it>KO mice is characterized by robust improvements of glucose disposal in both normal and metabolically challenged states, relative to WT controls. <it>GhrR </it>KO mice have an intact 1^stphase insulin response but require significantly less insulin for glucose disposal. Our experiments reveal that the insulin sensitivity of <it>GhrR </it>KO mice is due to both BW independent and dependent factors. We also provide several lines of evidence that a key feature of the <it>GhrR </it>KO mouse is maintenance of hepatic insulin sensitivity during metabolic challenge.</p

A proposal for a quality control protocol in breast CT with synchrotron radiation

The SYRMA-3D collaboration is setting up the first clinical trial of phase-contrast breast CT with synchrotron radiation at the Elettra synchrotron facility in Trieste, Italy. In this communication, a quality control protocol for breast CT is proposed, and a first test of image quality measurements is performed by means of a custom-made radiographic phantom. Materials and methods A set of projections is acquired and used to perform a CT reconstruction of two selected portions of the phantom. Such portions contain a uniform layer of water and a set of radiographic inserts, respectively. Together, they allow to perform several image quality measurements, namely CT number linearity, reconstruction accuracy, uniformity, noise, and low contrast resolution. All measurements are repeated at different beam energies in the range of interest, and at two different dose values. Results Measurements show a good linearity in the soft tissue range, paired to a high accuracy of the CT number reconstruction. Uniformity and noise measurements show that reconstruction inhomogeneities are bound to a few percent of the average pixel values. However, low contrast detectability is limited to the higher portion of the explored energy range. Conclusions The results of the measurements are satisfactory in terms of their quality, feasibility and reproducibility. With minimal modifications, the phantom is promising to allow a set of image quality measurements to be used in the upcoming clinical trial

Anti-vascular endothelial growth factor monotherapy or combined with verteporfin photodynamic therapy for retinal angiomatous proliferation: a systematic review with meta-analysis

: Purpose: To assess functional and anatomical outcomes of intravitreal anti-Vascular Endothelial Growth Factor (anti-VEGF) monotherapy versus combined with verteporfin Photodynamic Therapy (PDT) for Retinal Angiomatous Proliferation (RAP). Methods: Studies reporting outcomes of intravitreal anti-VEGF monotherapy and/or in combination with verteporfin PDT in RAP eyes with a follow-up ≥ 12&nbsp;months were searched. The primary outcome was the mean change in best corrected visual acuity (BCVA) at 12&nbsp;months. Mean change in central macular thickness (CMT) and mean number of injections were considered as secondary outcomes. The mean difference (MD) between pre- and post-treatment values was calculated along with 95% Confidence Interval (95% CI). Meta-regressions were performed to assess the influence of anti-VEGF number of injections on BCVA and CMT outcomes. Results: Thirty-four studies were included. A mean gain of 5.16 letters (95% CI = 3.30-7.01) and 10.38 letters (95% CI = 8.02-12.75) was shown in the anti-VEGF group and combined group, respectively (anti-VEGF group vs. combined group, p &lt; 0.01). A mean CMT reduction of 132.45&nbsp;µm (95% CI = from -154.99 to -109.90) and 213.93&nbsp;µm (95% CI = from -280.04 to -147.83) was shown in the anti-VEGF group and combined group, respectively (anti-VEGF group vs. combined group, p &lt; 0.02). A mean of 4.9 injections (95% CI = 4.2-5.6) and 2.8 injections (95% CI = 1.3-4.4) were administered over a 12-month period in the anti-VEGF group and combined group, respectively. Meta-regression analyses showed no influence of injection number on visual and CMT outcomes. High heterogeneity was found across studies for both functional and anatomical outcomes. Conclusion: A combined approach with anti-VEGF and PDT could provide better functional and anatomical outcomes in RAP eyes compared with anti-VEGF monotherapy

Characterization of transient and progressive pulmonary fibrosis by spatially correlated phase contrast microCT, classical histopathology and atomic force microscopy

: Pulmonary fibrosis (PF) is a severe and progressive condition in which the lung becomes scarred over time resulting in pulmonary function impairment. Classical histopathology remains an important tool for micro-structural tissue assessment in the diagnosis of PF. A novel workflow based on spatial correlated propagation-based phase-contrast micro computed tomography (PBI-microCT), atomic force microscopy (AFM) and histopathology was developed and applied to two different preclinical mouse models of PF - the commonly used and well characterized Bleomycin-induced PF and a novel mouse model for progressive PF caused by conditional Nedd4-2 KO. The aim was to integrate structural and mechanical features from hallmarks of fibrotic lung tissue remodeling. PBI-microCT was used to assess structural alteration in whole fixed and paraffin embedded lungs, allowing for identification of fibrotic foci within the 3D context of the entire organ and facilitating targeted microtome sectioning of planes of interest for subsequent histopathology. Subsequently, these sections of interest were subjected to AFM to assess changes in the local tissue stiffness of previously identified structures of interest. 3D whole organ analysis showed clear morphological differences in 3D tissue porosity between transient and progressive PF and control lungs. By integrating the results obtained from targeted AFM analysis, it was possible to discriminate between the Bleomycin model and the novel conditional Nedd4-2 KO model using agglomerative cluster analysis. As our workflow for 3D spatial correlation of PBI, targeted histopathology and subsequent AFM is tailored around the standard procedure of formalin-fixed paraffin-embedded (FFPE) tissue specimens, it may be a powerful tool for the comprehensive tissue assessment beyond the scope of PF and preclinical research