A CANDLE for a deeper in-vivo insight

A new Collaborative Approach for eNhanced Denoising under Low-light Excitation (CANDLE) is introduced for the processing of 3D laser scanning multiphoton microscopy images. CANDLE is designed to be robust for low signal-to-noise ratio (SNR) conditions typically encountered when imaging deep in scattering biological specimens. Based on an optimized non-local means filter involving the comparison of filtered patches, CANDLE locally adapts the amount of smoothing in order to deal with the noise inhomogeneity inherent to laser scanning fluorescence microscopy images. An extensive validation on synthetic data, images acquired on microspheres and in vivo images is presented. These experiments show that the CANDLE filter obtained competitive results compared to a state-of-the-art method and a locally adaptive optimized non-local means filter, especially under low SNR conditions (PSNR < 8 dB). Finally, the deeper imaging capabilities enabled by the proposed filter are demonstrated on deep tissue in vivo images of neurons and fine axonal processes in the Xenopus tadpole brain.We want to thank Florian Luisier for providing free plugin of his PureDenoise filter. We also want to thank Markku Makitalo for providing the code of their OVST. This study was supported by the Canadian Institutes of Health Research (CIHR, MOP-84360 to DLC and MOP-77567 to ESR) and Cda (CECR)-Gevas-OE016. MM holds a fellowship from the Deutscher Akademischer Austasch Dienst (DAAD) and a McGill Principal's Award. ESR is a tier 2 Canada Research Chair. This work has been partially supported by the Spanish Health Institute Carlos III through the RETICS Combiomed, RD07/0067/2001. This work benefited from the use of ImageJ.Coupé, P.; Munz, M.; Manjón Herrera, JV.; Ruthazer, ES.; Collins, DL. (2012). A CANDLE for a deeper in-vivo insight. Medical Image Analysis. 16(4):849-864. https://doi.org/10.1016/j.media.2012.01.002S84986416

Surface passivation of carbon nanoparticles with branched macromolecules influences near infrared bioimaging

A superior and commercially exploitable 'green synthesis' of optically active carbon nanoparticle (OCN) is revealed in this work. The naked carbon particles (<20 nm) were derived from commercial food grade honey. The fluorescence properties of these particles were significantly enhanced by utilizing hyberbranched polymer for surface passivation. A dramatic increase in near infrared emission was achieved compared to a linear polymer (PEG) coated carbon nanoparticles. Interestingly, as passivating agent becomes more extensively branched (pseudo generation 2 to 4), the average radiant efficiency amplifies considerably as a direct result of the increasing surface area available for light passivation. The particles showed negligible loss of cell viability in presence of endothelial cells in vitro. Preliminary in vivo experiment showed high contrast enhancement in auxiliary lymphnode in a mouse model. The exceptionally rapid lymphatic transport of these particles suggests that such an approach may offer greater convenience and reduced procedural expense, as well as improved surgical advantage as the patient is positioned on the table for easier resection

A comprehensive review on photoacoustic-based devices for biomedical applications

The photoacoustic effect is an emerging technology that has sparked significant interest in the research field since an acoustic wave can be produced simply by the incidence of light on a material or tissue. This phenomenon has been extensively investigated, not only to perform photoacoustic imaging but also to develop highly miniaturized ultrasound probes that can provide biologically meaningful information. Therefore, this review aims to outline the materials and their fabrication process that can be employed as photoacoustic targets, both biological and non-biological, and report the main components’ features to achieve a certain performance. When designing a device, it is of utmost importance to model it at an early stage for a deeper understanding and to ease the optimization process. As such, throughout this article, the different methods already implemented to model the photoacoustic effect are introduced, as well as the advantages and drawbacks inherent in each approach. However, some remaining challenges are still faced when developing such a system regarding its fabrication, modeling, and characterization, which are also discussed.This work was supported by Fundação para a Ciência e Tecnologia national funds, under the national support to R&D units grant, through the reference project UIDB/04436/2020 and UIDP/04436/2020

An assay to image neuronal microtubule dynamics in mice

Microtubule dynamics in neurons play critical roles in physiology, injury and disease and determine microtubule orientation, the cell biological correlate of neurite polarization. Several microtubule binding proteins, including end-binding protein 3 (EB3), specifically bind to the growing plus tip of microtubules. In the past, fluorescently tagged end-binding proteins have revealed microtubule dynamics in vitro and in non-mammalian model organisms. Here, we devise an imaging assay based on transgenic mice expressing yellow fluorescent protein-tagged EB3 to study microtubules in intact mammalian neurites. Our approach allows measurement of microtubule dynamics in vivo and ex vivo in peripheral nervous system and central nervous system neurites under physiological conditions and after exposure to microtubule-modifying drugs. We find an increase in dynamic microtubules after injury and in neurodegenerative disease states, before axons show morphological indications of degeneration or regrowth. Thus increased microtubule dynamics might serve as a general indicator of neurite remodelling in health and disease

Guareschi\u27s Mondo Piccolo and the Sacrality of Conscience

This study adopts a Christian hermeneutic to explore sacred themes in several of the 346 Don Camillo short stories that Giovannino Guareschi wrote between 1946 and 1966. Such a critical approach may seem non-traditional to use in analyzing a post-World War II, twentieth-century author. And yet, Guareschi defies convention in many ways beyond his profession as a journalist, humorist and popular author: he openly opposed the anti-clerical and Marxist literary establishment; defined himself as an anti-intellectual; and, as a layperson, he wrote unromantically about matters of faith. Especially as editor of the immensely popular weekly newspaper Candido, he had the perfect forum to reach millions of readers who shared his Christian values and were not part of the intellectual elite. To be sure, Don Camillo stories delight and earn frequent smiles and giggles, but the narrative action in best of them powerfully echoes Jesus of Nazareth’s call to conversion and forgiveness through the way characters heed their consciences

Multifunctional Polymeric Enveloped Nanocarriers: Targeting Extracellular and Intracellular Barriers

Over the past several years, employment of multifunctional polymeric excipients-based nanoparticles for controlled and targeted drug delivery of therapeutic modalities to mucosal membrane-based organelles and systemic circulation has gained enormous interest. Because they promise to resolve numerous key therapeutical issues associated with current clinical practice including low treatment efficacy and significant side effects. Potential controlled and targeted drug delivery systems, therefore, should be able to overcome not only extracellular barriers but also intracellular barriers. Extracellularly, targeted nanocarriers ought to provide extended circulation time, selective binding to the targeted mucosal tissues, long residence time at the site of absorption, and controlled drug release. Intracellularly, the targeted nanocarriers should offer cellular uptake, cellular localization, and endosomal release. Hence, this chapter will provide an overview of the unique chemistry of multifunctional polymeric enveloped diverse nanocarriers such as dendrimers, semiconducting polymer dots, quantum dots, carbon dots, and magnetic as versatile platform addressing both extracellular and intracellular barriers

Seeing the Big Picture: System Architecture Trends in Endoscopy and LED-Based hyperspectral Subsystem Intergration

Early-stage colorectal lesions remain difficult to detect. Early development of neoplasia tends to be small (less than 10 mm) and flat and difficult to distinguish from surrounding mucosa. Additionally, optical diagnosis of neoplasia as benign or malignant is problematic. Low rates of detection of these lesions allow for continued growth in the colorectum and increased risk of cancer formation. Therefore, it is crucial to detect neoplasia and other non-neoplastic lesions to determine risk and guide future treatment. Technology for detection needs to enhance contrast of subtle tissue differences in the colorectum and track multiple biomarkers simultaneously. This work implements one such technology with the potential to achieve the desired multi-contrast outcome for endoscopic screenings: hyperspectral imaging. Traditional endoscopic imaging uses a white light source and a RGB detector to visualize the colorectum using reflected light. Hyperspectral imaging (HSI) acquires an image over a range of individual wavelength bands to create an image hypercube with a wavelength dimension much deeper and more sensitive than that of an RGB image. A hypercube can consist of reflectance or fluorescence (or both) spectra depending on the filtering optics involved. Prior studies using HSI in endoscopy have normally involved ex vivo tissues or xiv optics that created a trade-off between spatial resolution, spectral discrimination and temporal sampling. This dissertation describes the systems design of an alternative HSI endoscopic imaging technology that can provide high spatial resolution, high spectral distinction and video-rate acquisition in vivo. The hyperspectral endoscopic system consists of a novel spectral illumination source for image acquisition dependent on the fluorescence excitation (instead of emission). Therefore, this work represents a novel contribution to the field of endoscopy in combining excitation-scanning hyperspectral imaging and endoscopy. This dissertation describes: 1) systems architecture of the endoscopic system in review of previous iterations and theoretical next-generation options, 2) feasibility testing of a LED-based hyperspectral endoscope system and 3) another LED-based spectral illuminator on a microscope platform to test multi-spectral contrast imaging. The results of the architecture point towards an endoscopic system with more complex imaging and increased computational capabilities. The hyperspectral endoscope platform proved feasibility of a LED-based spectral light source with a multi-furcated solid light guide. Another LED-based design was tested successfully on a microscope platform with a dual mirror array similar to telescope designs. Both feasibility tests emphasized optimization of coupling optics and combining multiple diffuse light sources to a common output. These results should lead to enhanced imagery for endoscopic tissue discrimination and future optical diagnosis for routine colonoscopy

Denoising of 3D magnetic resonance images using non-local PCA and Transform-Domain Filter

The Magnetic Resonance Imaging (MRI) technologyused in clinical diagnosis demands high Peak Signal-to-Noise ratio(PSNR) and improved resolution for accurate analysis and treatmentmonitoring. However, MRI data is often corrupted by random noisewhich degrades the quality of Magnetic Resonance (MR) images.Denoising is a paramount challenge as removing noise causesreduction in the fine details of MRI images. We have developed anovel algorithm which employs Principal Component Analysis(PCA) decomposition and Wiener filtering. We have proposed a twostage approach. In first stage, non-local PCA thresholding is appliedon noisy image and second stage uses Wiener filter over this filteredimage. Our algorithm is implemented using MATLAB andperformance is measured via PSNR. The proposed approach hasalso been compared with related state-of-art methods. Moreover, wepresent both qualitative and quantitative results which prove thatproposed algorithm gives superior denoising performance

Glycolytic Metabolism of Macrophages Differs by Spatial Location and Subset in Tuberculous Granulomas

Tuberculosis (TB), caused by infection with Mycobacterium tuberculosis (Mtb), triggers the formation of granulomas in the host. Granulomas are composed of many different types of host immune cells including T and B lymphocytes, macrophages, and neutrophils (PMN). The metabolic pathways used by immune cells in granulomas are important for cell function and glycolytic metabolic pathways in granulomas may be involved limiting or promoting disease. By understanding immunometabolism in TB granulomas, we can improve diagnosis and potentially create new therapeutics to combat TB disease. GLUT1 is a glucose transporter that transports glucose into the cell. To determine what cell subsets express GLUT1 in a granuloma, IHC was performed on lung granuloma-containing tissue sections from non-human primates (NHP) that were experimentally infected with Mtb. These slides were stained for macrophage markers including CD11c and CD163, and GLUT1, before being imaged by fluorescence microscopy. Image analysis was performed using ImageJ to determine the total pixel area and percent pixel area of each cell marker occupied in granuloma cross sections, as well as co-localization between the macrophage markers and GLUT1. To identify if there is a relationship between glucose uptake and mycobacterial antigens, we performed a glucose uptake assay and hypoxic experiments using 2-NBDG on monocyte-derived macrophages that were stimulated with inactivated Mtb. Image analysis revealed co-localization of different cell markers and GLUT1. When looking at co-localization of CD11c and CD163 with GLUT1, we found that CD11c+CD163- epithelioid macrophages, the cells in granulomas that are most commonly infected with Mtb, expressed more GLUT1 than interstitial and alveolar macrophages. Moreover, we see evidence that macrophages increase their glucose (2-NBDG) uptake when stimulated with inactivated Mtb. Identifying immune cells that express GLUT1 and what triggers these immune cells to switch to glycolytic metabolism will help us further understand overall granuloma metabolism and cell differentiation after Mtb infection. In terms of public health, by better understanding the immunometabolism of granulomas, it will improve monitoring of disease progression or to aid in the treatment of Mtb infection to help reduce tuberculosis cases worldwide