An innovative method for obtaining consistent images and quantification of histochemically stained specimens

Digital microscopy: A routine mandate in future? A leaf out of Covid-19 pandemic laboratory experience

The COVID-19 pandemic has brought out lot of changes among the way people and organisations function. It has also reduced social gatherings and hence social relations considerably, forcing people to adjust to new ways of work and life. An outstanding difference between the current COVID-19 pandemic and previous epidemics or pandemics is the increased availability and use of technology currently, which has been validated by various reports from across the globe. Thus, even with the ensuing pandemic, lockdown and decreased social gatherings, with the technology support we have devised ways to keep in contact with friends, family and work place, so as to continue our lives. Social distancing guidelines and regulations have put pressure on a great many organisations to find new ways of keeping employees and students connected while working remotely. For more deskbound occupations and roles, this can be relatively straightforward, but it is challenging if not impossible for lab-based quality control, research and study. The answer to this is digital remote microscopy which enables sharing of data online, carrying out collaborative work through multi-viewing in real time and facilitates remote training functions.

Computational Analysis of Pathological Image Enables Interpretable Prediction for Microsatellite Instability

Background

Microsatellite instability (MSI) is associated with several tumor types and has become increasingly vital in guiding patient treatment decisions; however, reasonably distinguishing MSI from its counterpart is challenging in clinical practice.

Methods

In this study, interpretable pathological image analysis strategies are established to help medical experts to identify MSI. The strategies only require ubiquitous hematoxylin and eosin–stained whole-slide images and perform well in the three cohorts collected from The Cancer Genome Atlas. Equipped with machine learning and image processing technique, intelligent models are established to diagnose MSI based on pathological images, providing the rationale of the decision in both image level and pathological feature level.

Findings

The strategies achieve two levels of interpretability. First, the image-level interpretability is achieved by generating localization heat maps of important regions based on deep learning. Second, the feature-level interpretability is attained through feature importance and pathological feature interaction analysis. Interestingly, from both the image-level and feature-level interpretability, color and texture characteristics, as well as their interaction, are shown to be mostly contributed to the MSI prediction.

Interpretation

The developed transparent machine learning pipeline is able to detect MSI efficiently and provide comprehensive clinical insights to pathologists. The comprehensible heat maps and features in the intelligent pipeline reflect extra- and intra-cellular acid–base balance shift in MSI tumor.

Excessive release of inorganic phosphate by ALS/FTD astrocytes causes non-cell-autonomous toxicity to motoneurons

Non-cell-autonomous mechanisms contribute to neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), in which astrocytes release unidentified factors that are toxic to motoneurons (MNs). We report here that mouse and patient iPSC-derived astrocytes with diverse ALS/FTD-linked mutations (SOD1, TARDBP, and C9ORF72) display elevated levels of intracellular inorganic polyphosphate (polyP), a ubiquitous, negatively charged biopolymer. PolyP levels are also increased in astrocyte-conditioned media (ACM) from ALS/FTD astrocytes. ACM-mediated MN death is prevented by degrading or neutralizing polyP in ALS/FTD astrocytes or ACM. Studies further reveal that postmortem familial and sporadic ALS spinal cord sections display enriched polyP staining signals and that ALS cerebrospinal fluid (CSF) exhibits increased polyP concentrations. Our in vitro results establish excessive astrocyte-derived polyP as a critical factor in non-cell-autonomous MN degeneration and a potential therapeutic target for ALS/FTD. The CSF data indicate that polyP might serve as a new biomarker for ALS/FTD.

The Application, Challenges, and Advancement Toward Regulatory Acceptance of Digital Toxicologic Pathology: Results of the 7th ESTP International Expert Workshop (September 20-21, 2019)

With advancements in whole slide imaging technology and improved understanding of the features of pathologist workstations required for digital slide evaluation, many institutions are investigating broad digital pathology adoption. The benefits of digital pathology evaluation include remote access to study or diagnostic case materials and integration of analysis and reporting tools. Diagnosis based on whole slide images is established in human medical pathology, and the use of digital pathology in toxicologic pathology is increasing. However, there has not been broad adoption in toxicologic pathology, particularly in the context of regulatory studies, due to lack of precedence. To address this topic, as well as practical aspects, the European Society of Toxicologic Pathology coordinated an expert international workshop to assess current applications and challenges and outline a set of minimal requirements needed to gain future regulatory acceptance for the use of digital toxicologic pathology workflows in research and development, so that toxicologic pathologists can benefit from digital slide technology.

Digital Microscopy, Image Analysis, and Virtual Slide Repository

Advancements in technology and digitization have ushered in novel ways of enhancing tissue-based research via digital microscopy and image analysis. Whole slide imaging scanners enable digitization of histology slides to be stored in virtual slide repositories and to be viewed via computers instead of microscopes. Easier and faster sharing of histologic images for teaching and consultation, improved storage and preservation of quality of stained slides, and annotation of features of interest in the digital slides are just a few of the advantages of this technology. Combined with the development of software for digital image analysis, digital slides further pave the way for the development of tools that extract quantitative data from tissue-based studies. This review introduces digital microscopy and pathology, and addresses technical and scientific considerations in slide scanning, quantitative image analysis, and slide repositories. It also highlights the current state of the technology and factors that need to be taken into account to insure optimal utility, including preanalytical considerations and the importance of involving a pathologist in all major steps along the digital microscopy and pathology workflow.

Accurate representation of interference colours (Michel-Lévy chart): from rendering to image colour correction

Here a work flow towards an accurate representation of interference colours (Michel-Lévy chart) digitally captured on a polarised light microscope using dry and oil immersion objectives is presented. The work flow includes accurate rendering of interference colours considering the colour temperature of the light source of the microscope and chromatic adaptation to white points of RGB colour spaces as well as the colour correction of the camera using readily available colour targets. The quality of different colour correction profiles was tested independently on an IT8.7/1 target. The best performing profile was using the XYZ cLUT algorithm and it revealed a ΔE₀₀ of 1.9 (6.4 no profile) at 5× and 1.1 (8.4 no profile) at 100× magnification, respectively. The overall performance of the workflow was tested by comparing rendered interference colours with colour-corrected images of a quartz wedge captured over a retardation range from 80-2500 nm at 5× magnification. Uncorrected images of the quartz wedge in sRGB colour space revealed a mean ΔE₀₀ of 12.3, which could be reduced to a mean of 4.9 by applying a camera correction profile based on an IT8.7/1 target and the Matrix only algorithm (ΔE₀₀ < 1.0 signifies colour differences imperceptible by the human eye). ΔE₀₀ varied significantly over the retardation range of 80-2500 nm of the quartz wedge, but the reasons for this variation is not well understood and the quality of colour correction might be further improved in future by using custom made colour targets specifically designed for the analysis of high-order interference colours.

Development of a sheep challenge model for Rift Valley fever

Rift Valley fever (RVF) is a zoonotic disease that causes severe epizootics in ruminants, characterized by mass abortion and high mortality rates in younger animals. The development of a reliable challenge model is an important prerequisite for evaluation of existing and novel vaccines. A study aimed at comparing the pathogenesis of RVF virus infection in US sheep using two genetically different wild type strains of the virus (SA01-1322 and Kenya-128B-15) was performed. A group of sheep was inoculated with both strains and all infected sheep manifested early-onset viremia accompanied by a transient increase in temperatures. The Kenya-128B-15 strain manifested higher virulence compared to SA01-1322 by inducing more severe liver damage, and longer and higher viremia. Genome sequence analysis revealed sequence variations between the two isolates, which potentially could account for the observed phenotypic differences. We conclude that Kenya-128B-15 sheep infection represents a good and virulent challenge model for RVF.