Histological Hyperspectral Glioblastoma Dataset (HistologyHSI-GB).

Hyperspectral (HS) imaging (HSI) technology combines the main features of two existing technologies: imaging and spectroscopy. This allows to analyse simultaneously the morphological and chemical attributes of the objects captured by a HS camera. In recent years, the use of HSI provides valuable insights into the interaction between light and biological tissues, and makes it possible to detect patterns, cells, or biomarkers, thus, being able to identify diseases. This work presents the HistologyHSI-GB dataset, which contains 469 HS images from 13 patients diagnosed with brain tumours, specifically glioblastoma. The slides were stained with haematoxylin and eosin (H&E) and captured using a microscope at 20× power magnification. Skilled histopathologists diagnosed the slides and provided image-level annotations. The dataset was acquired using custom HSI instrumentation, consisting of a microscope equipped with an HS camera covering the spectral range from 400 to 1000 nm.

APP-BACE1 Interaction and Intracellular Localization Regulate Aß Production in iPSC-Derived Cortical Neurons.

Alzheimer's disease (AD) is characterized pathologically by amyloid ß (Aß)-containing plaques. Generation of Aß from amyloid precursor protein (APP) by two enzymes, ß- and γ-secretase, has therefore been in the AD research spotlight for decades. Despite this, how the physical interaction of APP with the secretases influences APP processing is not fully understood. Herein, we compared two genetically identical human iPSC-derived neuronal cell types: low Aß-secreting neuroprogenitor cells (NPCs) and high Aß-secreting mature neurons, as models of low versus high Aß production. We investigated levels of substrate, enzymes and products of APP amyloidogenic processing and correlated them with the proximity of APP to ß- and γ-secretase in endo-lysosomal organelles. In mature neurons, increased colocalization of full-length APP with the ß-secretase BACE1 correlated with increased ß-cleavage product sAPPß. Increased flAPP/BACE1 colocalization was mainly found in early endosomes. In the same way, increased colocalization of APP-derived C-terminal fragment (CTF) with presenilin-1 (PSEN1), the catalytic subunit of γ-secretase, was seen in neurons as compared to NPCs. Furthermore, most of the interaction of APP with BACE1 in low Aß-secreting NPCs seemed to derive from CTF, the remaining APP part after BACE1 cleavage, indicating a possible novel product-enzyme inhibition. In conclusion, our results suggest that interaction of APP and APP cleavage products with their secretases can regulate Aß production both positively and negatively. ß- and γ-Secretases are difficult targets for AD treatment due to their ubiquitous nature and wide range of substrates. Therefore, targeting APP-secretase interactions could be a novel treatment strategy for AD. Colocalization of APP species with BACE1 in a novel model of low- versus high-Aß secretion-Two genetically identical human iPSC-derived neuronal cell types: low Aß-secreting neuroprogenitor cells (NPCs) and high Aß secreting mature neurons, were compared. Increased full-length APP (flAPP)/BACE1 colocalization in early endosomes was seen in neurons, while APP-CTF/BACE1 colocalization was much higher than flAPP/BACE1 colocalization in NPCs, although the cellular location was not determined.

The bovine dialyzable leukocyte extract, immunepotent CRP, synergically enhances cyclophosphamide-induced breast cancer cell death, through a caspase-independent mechanism.

Breast cancer (BC) is one of the leading causes of cancer death worldwide. Cyclophosphamide (CTX) remains a mainstay in cancer therapy despite harmful adverse effects and cell death-resistances. To face this, combinational therapy of chemotherapies and immunotherapies has been proposed. IMMUNEPOTENT CRP (ICRP) is an immunotherapy that has cytotoxic effects in several cancer cells without affecting peripheral blood mononuclear cells (PBMC) and CD3+ cells. The aim of this study was to evaluate cytotoxicity, the type of cytotoxic effect, and several features involved in cell death induced by the combination of CTX with ICRP (ICRP+CTX) in breast cancer cells as well as their effect on healthy cells. For this purpose, human and murine breast cancer cells, MCF-7, MDA-MB-231 and 4T1, or PBMC were treated for 24 hours with ICRP, CTX or ICRP+CTX in different combination ratios for the assessment of cell death. Flow cytometry and microscopy were used to determine biochemical and morphological characteristics of cell death. Assays showed that ICRP in combination with CTX induce potentiated cell death manifested with morphological changes, loss of mitochondrial membrane potential, reactive oxygen species (ROS) production, and caspase activation. In addition, it was determined that ICRP+CTX-cell death is caspase-independent in all the breast cancer cells assessed. On the other hand, ICRP did not affect CTX-cytotoxicity in PBMC. For all the above, we can propose that the combination of ICRP with CTX an effective combination therapy, promoting their use even in tumoral cells with defects on proteins implicated in the apoptotic pathway.

Unravelling 3D Dynamics and Hydrodynamics during Incorporation of Dielectric Particles to an Optical Trapping Site.

Mapping of the spatial and temporal motion of particles inside an optical field is critical for understanding and further improvement of the 3D spatio-temporal control over their optical trapping dynamics. However, it is not trivial to capture the 3D motion, and most imaging systems only capture a 2D projection of the 3D motion, in which the information about the axial movement is not directly available. In this work, we resolve the 3D incorporation trajectories of 200 nm fluorescent polystyrene particles in an optical trapping site under different optical experimental conditions using a recently developed widefield multiplane microscope (imaging volume of 50 × 50 × 4 µm3). The particles are gathered at the focus following some preferential 3D channels that show a shallow cone distribution. We demonstrate that the radial and the axial flow speed components depend on the axial distance from the focus, which is directly related to the scattering/gradient optical forces. While particle velocities and trajectories are mainly determined by the trapping laser profile, they cannot be completely explained without considering collective effects resulting from hydrodynamic forces.

Variables hemodinámicas cardíacas y desenlaces postrasplante hepático en un centro de referencia de trasplantes en Colombia a 2600 metros sobre el nivel del mar / Cardiac hemodynamic variables and post-liver transplant outcomes in a transplant referral center in Colombia at 2,600 meters above sea level

Resumen Introducción: la valoración hemodinámica mediante ecocardiografía Doppler tiene importancia en la identificación de alteraciones sistólicas/diastólicas como predictor de desenlaces en el postrasplante hepático desde alteraciones cardiovasculares hasta disfunción del injerto y mortalidad. Métodos: estudio de cohorte retrospectivo. Paciente con trasplante hepático en el hospital LaCardio, en Bogotá, Colombia entre enero de 2005 y julio de 2021. Análisis de variables sociodemográficas, comorbilidades, ecocardiografía y variables intraoperatorias con desenlaces primarios como disfunción temprana del injerto, lesión renal aguda (LRA) y mortalidad durante el seguimiento. Se realizó un árbol de clasificación y regresión (CART). Resultados: se analizaron a 397 pacientes, el 54,4% eran hombres, y el 71% tenía algún grado de disfunción diastólica, hipertrofia ventricular izquierda (30,9%) con presencia de disfunción del injerto en el 8% y LRA en el 21%, y una mortalidad del 15% durante el seguimiento del estudio. En el modelo CART para desenlaces de mortalidad y disfunción del injerto se relacionó con la presencia de índice de masa corporal (IMC) < 19 o la combinación de IMC entre 19 y < 24 con diálisis. Conclusión: las variables ecocardiográficas, la sarcopenia y la LRA o requerimiento de terapia de reemplazo renal se relacionan con desenlaces de mortalidad y disfunción del injerto.

Abstract Introduction: Hemodynamic assessment by Doppler echocardiography is essential in identifying systolic/diastolic changes as a predictor of outcomes in post-liver transplantation, from cardiovascular changes to graft dysfunction and mortality. Materials and methods: Retrospective cohort study. Patient with a liver transplant at the LaCardio hospital in Bogotá, Colombia, between January 2005 and July 2021. Analysis of sociodemographic variables, comorbidities, echocardiography, and intraoperative variables with primary outcomes such as early graft dysfunction, acute kidney injury (AKI), and mortality during follow-up. A classification and regression tree (CART) was performed. Results: 397 patients were analyzed; 54.4% were men, 71% had some degree of diastolic dysfunction and left ventricular hypertrophy (30.9%) with graft dysfunction in 8% and AKI in 21%, and a mortality of 15% during the study follow-up. In the CART model, mortality and graft dysfunction outcomes were related to a body mass index (BMI) < 19 or a combination of BMI between 19 and < 24 with dialysis. Conclusion: Echocardiographic variables, sarcopenia, AKI, or the requirement for renal replacement therapy are related to mortality and graft dysfunction outcomes.

Chemical traits of cerebral amyloid angiopathy in familial British-, Danish-, and non-Alzheimer's dementias.

Familial British dementia (FBD) and familial Danish dementia (FDD) are autosomal dominant forms of dementia caused by mutations in the integral membrane protein 2B (ITM2B, also known as BRI2) gene. Secretase processing of mutant BRI2 leads to secretion and deposition of BRI2-derived amyloidogenic peptides, ABri and ADan that resemble APP/ß-amyloid (Aß) pathology, which is characteristic of Alzheimer's disease (AD). Amyloid pathology in FBD/FDD manifests itself predominantly in the microvasculature by ABri/ADan containing cerebral amyloid angiopathy (CAA). While ABri and ADan peptide sequences differ only in a few C-terminal amino acids, CAA in FDD is characterized by co-aggregation of ADan with Aß, while in contrast no Aß deposition is observed in FBD. The fact that FDD patients display an earlier and more severe disease onset than FBD suggests a potential role of ADan and Aß co-aggregation that promotes a more rapid disease progression in FDD compared to FBD. It is therefore critical to delineate the chemical signatures of amyloid aggregation in these two vascular dementias. This in turn will increase the knowledge on the pathophysiology of these diseases and the pathogenic role of heterogenous amyloid peptide interactions and deposition, respectively. Herein, we used matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) in combination with hyperspectral, confocal microscopy based on luminescent conjugated oligothiophene probes (LCO) to delineate the structural traits and associated amyloid peptide patterns of single CAA in postmortem brain tissue of patients with FBD, FDD as well as sporadic CAA without AD (CAA+) that show pronounced CAA without parenchymal plaques. The results show that CAA in both FBD and FDD consist of N-terminally truncated- and pyroglutamate-modified amyloid peptide species (ADan and ABri), but that ADan peptides in FDD are also extensively C-terminally truncated as compared to ABri in FBD, which contributes to hydrophobicity of ADan species. Further, CAA in FDD showed co-deposition with Aß x-42 and Aß x-40 species. CAA+ vessels were structurally more mature than FDD/FBD CAA and contained significant amounts of pyroglutamated Aß. When compared with FDD, Aß in CAA+ showed more C-terminal and less N-terminally truncations. In FDD, ADan showed spatial co-localization with Aß3pE-40 and Aß3-40 but not with Aßx-42 species. This suggests an increased aggregation propensity of Aß in FDD that promotes co-aggregation of both Aß and ADan. Further, CAA maturity appears to be mainly governed by Aß content based on the significantly higher 500/580 patterns observed in CAA+ than in FDD and FBD, respectively. Together this is the first study of its kind on comprehensive delineation of Bri2 and APP-derived amyloid peptides in single vascular plaques in both FDD/FBD and sporadic CAA that provides new insight in non-AD-related vascular amyloid pathology. Cover Image for this issue: https://doi.org/10.1111/jnc.15424.

The primeval optical evolving matter by optical binding inside and outside the photon beam.

Optical binding has recently gained considerable attention because it enables the light-induced assembly of many-body systems; however, this phenomenon has only been described between directly irradiated particles. Here, we demonstrate that optical binding can occur outside the focal spot of a single tightly focused laser beam. By trapping at an interface, we assemble up to three gold nanoparticles with a linear arrangement which fully-occupies the laser focus. The trapping laser is efficiently scattered by this linear alignment and interacts with particles outside the focus area, generating several discrete arc-shape potential wells with a half-wavelength periodicity. Those external nanoparticles inside the arcs show a correlated motion not only with the linear aligned particles, but also between themselves even both are not directly illuminated. We propose that the particles are optically bound outside the focal spot by the back-scattered light and multi-channel light scattering, forming a dynamic optical binding network.

Sarcoma de la vena pulmonar / Sarcoma of the pulmonary vein

Resumen Los sarcomas son neoplasias primarias, cuya ubicación es rara en grandes vasos y excepcional en las venas pulmonares. Los dos tipos más frecuentes en las venas pulmonares son el leiomiosarcoma y el fibrosarcoma, con una distribución alrededor de la cuarta a la quinta décadas de vida, un pronóstico de 23 meses y 60% de metástasis al momento del diagnóstico. La presentación clínica es inespecífica ya que simula situaciones como embolia pulmonar, falla cardiaca descompensada y masa en la aurícula izquierda. Para su diagnóstico se cuenta con diferentes herramientas, como la ecocardiografía, la tomografía computarizada, la angiografía coronaria, la resonancia magnética y la tomografía por emisión de positrones (PET TC). El tratamiento incluye resección quirúrgica radical, manejo adyuvante con quimioterapia y radioterapia, e incluso, en casos seleccionados, trasplante de corazón. Se presenta el caso de una paciente con diagnóstico inicial de embolia pulmonar, con un episodio de edema pulmonar secundario a masa en la aurícula izquierda y extensión de un sarcoma de vena pulmonar derecha, con desenlace fatal. Se aporta a la literatura con el caso y la revisión de tema.

Abstract Sarcomas are primary neoplasms, whose location is rare in large vessels and in the pulmonary veins is exceptional. The two most frequent types in the pulmonary vein are leiomyosarcoma and fibrosarcoma, distribution around 4 and 5 decades of life, with a prognosis of 23 months and 60% metastasis at the time of diagnosis. The clinical presentation is nonspecific simulating situations such as pulmonary embolism, decompensated heart failure and mass in the left atrium. Different tools are available for its diagnosis, like echocardiography, computed tomography, coronary angiography, magnetic resonance imaging and PET CT. Treatment includes radical surgical resection, adjuvant therapy with chemotherapy, and radiation therapy, even heart transplantation in selected cases. It is presented the case of a patient with an initial diagnosis of pulmonary embolism, with an episode of pulmonary edema secondary to a mass in the left atrium, extension of a sarcoma of the right pulmonary vein, with a fatal outcome. We contributed to the literature with the case and review of theme.

Cyclophosphamide and epirubicin induce high apoptosis in microglia cells while epirubicin provokes DNA damage and microglial activation at sub-lethal concentrations.

Chemotherapy Related Cognitive Impairment (CRCI), also called chemobrain, diminishes cancer patient's life quality. Breast cancer (BC) patients have been described to be importantly affected, however, the mechanism leading to CRCI has not been fully elucidated. Recent research proposes microglia as the main architect of CRCI, thus dysregulations in these cells could trigger CRCI. The aim of this research was to evaluate the effects of two drugs commonly used against breast cancer, cyclophosphamide (CTX) and epirubicin (EPI), on the microglia cell line SIM-A9, using the BC cell line, 4T1, as a control. Our results show that CTX and EPI decrease microglia-cell viability and increase cell death on a concentration-dependent manner, being 5 and 2 times more cytotoxic to microglia cell line than to breast cancer 4T1cells, respectively. Both chemotherapies induce cell cycle arrest and a significant increase in p53, p16 and γ-H2AX in breast cancer and microglia cells. Furthermore, mitochondrial membrane potential (ΔΨm) diminishes as cell death increases, and both chemotherapies induce reactive oxygen species (ROS) production on SIM-A9 and 4T1. Moreover, caspase activation increases with treatments and its pharmacological blockade inhibits CTX and EPI induced-cell death. Finally, low concentrations of CTX and EPI induce γ-H2AX, and EPI induces cytokine release, NO production and Iba-1 overexpression. These findings indicate that microglia cells are more sensitive to CTX and EPI than BC cells and undergo DNA damage and cell cycle arrest at very low concentrations, moreover EPI induces microglia activation and a pro-inflammatory profile.

Energy transfer in multi-funnel systems quantitatively assessed by two-dimensional polarization imaging and single funnel approximation: From single molecules to ensembles.

Two-dimensional polarization imaging (2D POLIM) is an experimental method where correlations between fluorescence excitation- and fluorescence emission-polarization properties are measured. One way to analyze 2D POLIM data is to apply a so-called single funnel approximation (SFA). The SFA allows for quantitative assessment of energy transfer between chromophores with identical spectra [homo-FRET (Förster resonance energy transfer)]. In this paper, we run a series of computer experiments to investigate the applicability of the analysis based on the SFA to various systems ranging from single multichromophoric systems to isotropic ensembles. By setting various scenarios of energy transfer between individual chromophores within a single object, we were able to define the borders of the practical application of SFA. It allowed us to reach a more comprehensive interpretation of the experimental data in terms of uncovering the internal arrangement of chromophores in the system and energy transfer between them. We also found that the SFA can always formally explain the data for isotropic ensembles and derived a formula connecting the energy funneling efficiency parameter and traditional fluorescence anisotropy.

Aggressive Afterload Lowering to Improve the Right Ventricle: A New Target for Medical Therapy in Pulmonary Arterial Hypertension?

Despite numerous therapeutic advances in pulmonary arterial hypertension, patients continue to suffer high morbidity and mortality, particularly considering a median age of 50 years. This article explores whether early, robust reduction of right ventricular afterload would facilitate substantial improvement in right ventricular function and thus whether afterload reduction should be a treatment goal for pulmonary arterial hypertension. The earliest clinical studies of prostanoid treatment in pulmonary arterial hypertension demonstrated an important link between lowering mean pulmonary arterial pressure (or pulmonary vascular resistance) and improved survival. Subsequent studies of oral monotherapy or sequential combination therapy demonstrated smaller reductions in mean pulmonary arterial pressure and pulmonary vascular resistance. More recently, retrospective reports of initial aggressive prostanoid treatment or initial combination oral and parenteral therapy have shown marked afterload reduction along with significant improvements in right ventricular function. Some data suggest that reaching threshold levels for pressure or resistance (components of right ventricular afterload) may be key to interrupting the self-perpetuating injury of pulmonary vascular disease in pulmonary arterial hypertension and could translate into improved long-term clinical outcomes. Based on these clues, the authors postulate that improved clinical outcomes might be achieved by targeting significant afterload reduction with initial oral combination therapy and early parenteral prostanoids.

Hafnia alvei pneumonia: from bees to human beings.

INTRODUCTION: Hafnia alvei is an enterobacteria that is a common inhabitant of the gastrointestinal flora of bees, birds, fish, and mammals. In humans this enterobacteria has been recovered from the oropharynx and the gastrointestinal tract but it has been rarely reported as a pathogen and usually identified as hospital-acquired enterobacteria. CASE REPORT: We describe a case of a 57-year-old woman, previously healthy, with a 7-day history of cough with brown sputum, sudden onset of chills, subjective fever, malaise, and pleuritic pain in the right hemithorax. A diagnosis of community-acquired pneumonia (CAP) was suspected and empiric antibiotic treatment was started. However, the patient showed no response and developed hemoptysis. A diagnosis of CAP by Hafnia alvei was confirmed with bronchoalveolar lavage and the patient was treated with i.v. cefepime 2 g TID with a good response. CONCLUSIONS: We presented a case of community-acquired pneumonia by Hafnia alvei in a previously healthy patient that, as far as our knowledge reaches, is the third reported case of CAP secondary to this pathogen.

Insights into the structure and function of the C-terminus of SGTs (small glutamine-rich TPR-containing proteins): A study of the Aedes aegypti homolog.

SGTs (small glutamine-rich TPR-containing proteins) are dimeric proteins that belong to the class of co-chaperones characterized by the presence of TPR domains (containing tetratricopeptide repeats). Human (SGTA) and yeast (Sgt2) SGTs are characterized by three distinct domains: an N-terminal dimerization domain, a central TPR-domain important for binding to other proteins (chaperones included) and a C-terminal domain involved in hydrophobic interactions. Both these SGTs are involved in the cellular PQC (protein quality control) system, as they interact with chaperones and have functions that aid stress recovery. However, there are differences between them, such as structural features and binding specificities, that could be better understood if other orthologous proteins were studied. Therefore, we produced and characterized a putative SGT protein, designated AaSGT, from the mosquito Aedes aegypti, which is a vector of several diseases, such as dengue and Zika. The protein was produced as a folded dimer which was stable up to 40 °C and was capable of binding to AaHsp90 and fully protecting a model protein, α-synuclein, from aggregation. The conformation of AaSGT was investigated by biophysical tools and small angle X-ray scattering, which showed that the protein had an elongated conformation and that its C-terminal domain was mainly disordered. The results with a C-terminal deletion mutant supported these observations. Altogether, these results are consistent with those from other functional SGT proteins and add to the understanding of the PQC system in Aedes aegypti, an important aim that may help to develop inhibitory strategies against this vector of neglected diseases.

Fast-tracking of single emitters in large volumes with nanometer precision.

Multifocal plane microscopy allows for capturing images at different focal planes simultaneously. Using a proprietary prism which splits the emitted light into paths of different lengths, images at 8 different focal depths were obtained, covering a volume of 50x50x4 µm3. The position of single emitters was retrieved using a phasor-based approach across the different imaging planes, with better than 10 nm precision in the axial direction. We validated the accuracy of this approach by tracking fluorescent beads in 3D to calculate water viscosity. The fast acquisition rate (>100 fps) also enabled us to follow the capturing of 0.2 µm fluorescent beads into an optical trap.

Amyloid precursor protein-b facilitates cell adhesion during early development in zebrafish.

Understanding the biological function of amyloid beta (Aß) precursor protein (APP) beyond its role in Alzheimer's disease is emerging. Yet, its function during embryonic development is poorly understood. The zebrafish APP orthologue, Appb, is strongly expressed during early development but thus far has only been studied via morpholino-mediated knockdown. Zebrafish enables analysis of cellular processes in an ontogenic context, which is limited in many other vertebrates. We characterized zebrafish carrying a homozygous mutation that introduces a premature stop in exon 2 of the appb gene. We report that appb mutants are significantly smaller until 2 dpf and display perturbed enveloping layer (EVL) integrity and cell protrusions at the blastula stage. Moreover, appb mutants surviving beyond 48 hpf exhibited no behavioral defects at 6 dpf and developed into healthy and fertile adults. The expression of the app family member, appa, was also found to be altered in appb mutants. Taken together, we show that appb is involved in the initial development of zebrafish by supporting the integrity of the EVL, likely by mediating cell adhesion properties. The loss of Appb might then be compensated for by other app family members to maintain normal development.

Image-Based Dynamic Phenotyping Reveals Genetic Determinants of Filamentation-Mediated ß-Lactam Tolerance.

Antibiotic tolerance characterized by slow killing of bacteria in response to a drug can lead to treatment failure and promote the emergence of resistance. ß-lactam antibiotics inhibit cell wall growth in bacteria and many of them cause filamentation followed by cell lysis. Hence delayed cell lysis can lead to ß-lactam tolerance. Systematic discovery of genetic factors that affect ß-lactam killing kinetics has not been performed before due to challenges in high-throughput, dynamic analysis of viability of filamented cells during bactericidal action. We implemented a high-throughput time-resolved microscopy approach in a gene deletion library of Escherichia coli to monitor the response of mutants to the ß-lactam cephalexin. Changes in frequency of lysed and intact cells due to the antibiotic action uncovered several strains with atypical lysis kinetics. Filamentation confers tolerance because antibiotic removal before lysis leads to recovery through numerous concurrent divisions of filamented cells. Filamentation-mediated tolerance was not associated with resistance, and therefore this phenotype is not discernible through most antibiotic susceptibility methods. We find that deletion of Tol-Pal proteins TolQ, TolR, or Pal but not TolA, TolB, or CpoB leads to rapid killing by ß-lactams. We also show that the timing of cell wall degradation determines the lysis and killing kinetics after ß-lactam treatment. Altogether, this study uncovers numerous genetic determinants of hitherto unappreciated filamentation-mediated ß-lactam tolerance and support the growing call for considering antibiotic tolerance in clinical evaluation of pathogens. More generally, the microscopy screening methodology described here can easily be adapted to study lysis in large numbers of strains.

Structural characterization of fibrous synthetic hydrogels using fluorescence microscopy.

The structural features of the matrix surrounding the cells play a crucial role in regulating their behavior. Here, we used fluorescence microscopy and customized analysis algorithms to characterize the architecture of fibrous hydrogel networks. As a model system, we investigated a new class of synthetic biomimetic material, hydrogels prepared from polyisocyanides. Our results show that these synthetic gels present a highly heterogeneous fibrous network, with pores reaching a few micrometers in diameter. By encapsulating HeLa cells in different hydrogels, we show that a more porous structure is linked to a higher proliferation rate. The approach described here, for the characterization of the network of fibrous hydrogels, can be easily applied to other polymer-based materials and provide new insights into the influence of structural features in cell behavior. This knowledge is crucial to develop the next generation of biomimetic materials for 3D cell models and tissue engineering applications.

Hyperspectral Imaging for the Detection of Glioblastoma Tumor Cells in H&E Slides Using Convolutional Neural Networks.

Hyperspectral imaging (HSI) technology has demonstrated potential to provide useful information about the chemical composition of tissue and its morphological features in a single image modality. Deep learning (DL) techniques have demonstrated the ability of automatic feature extraction from data for a successful classification. In this study, we exploit HSI and DL for the automatic differentiation of glioblastoma (GB) and non-tumor tissue on hematoxylin and eosin (H&E) stained histological slides of human brain tissue. GB detection is a challenging application, showing high heterogeneity in the cellular morphology across different patients. We employed an HSI microscope, with a spectral range from 400 to 1000 nm, to collect 517 HS cubes from 13 GB patients using 20× magnification. Using a convolutional neural network (CNN), we were able to automatically detect GB within the pathological slides, achieving average sensitivity and specificity values of 88% and 77%, respectively, representing an improvement of 7% and 8% respectively, as compared to the results obtained using RGB (red, green, and blue) images. This study demonstrates that the combination of hyperspectral microscopic imaging and deep learning is a promising tool for future computational pathologies.

Fluorescence Photobleaching as an Intrinsic Tool to Quantify the 3D Expansion Factor of Biological Samples in Expansion Microscopy.

Four years after its first report, expansion microscopy (ExM) is now being routinely applied in laboratories worldwide to achieve super-resolution imaging on conventional fluorescence microscopes. By chemically anchoring all molecules of interest to the polymer meshwork of an expandable hydrogel, their physical distance is increased by a factor of ∼4-5× upon dialysis in water, resulting in an imprint of the original sample with a lateral resolution up to 50-70 nm. To ensure a correct representation of the original spatial distribution of the molecules, it is crucial to confirm that the expansion is isotropic, preferentially in all three dimensions. To address this, we present an approach to evaluate the local expansion factor within a biological sample and in all three dimensions. We use photobleaching to introduce well-defined three-dimensional (3D) features in the cell and, by comparing the size and shape pre- and postexpansion, these features can be used as an intrinsic ruler. In addition, our method is capable of pointing out sample distortions and can be used as a quality control tool for expansion microscopy experiments in biological samples.

TRANSTHORACIC ECHOCARDIOGRAPHY IN NONSEDATED, FREE-RANGING HEALTHY AGOUTIS (DASYPROCTA AZARAE).

Most of the agouti species are kept in captivity, including the species Dasyprocta azarae. These animals are of zootechnical interest and, in addition, they can potentially be used as experimentation models because of their physical characteristics and possibility of manipulation. Therefore, the purpose of this study was to investigate the feasibility of the echocardiographic exam in nonsedated agoutis and to determine the normal reference ranges for the standard transthoracic echocardiographic parameters in healthy, adult, free-ranging agoutis found in an urban wood and intended for scientific investigations. Most of the echocardiographic parameters evaluated were similar to what has already been described for other rodent species such as rabbits or the Dasyprocta primnolopha agoutis. Based on the information compiled in this study, echocardiographic examination is feasible in awake adult, free-ranging agoutis. The results obtained from the morphologic and hemodynamic evaluation of the heart can help in future studies, either involving the clinical aspects or considering the potential use of these animals as an experimental model.