Enhanced spectral histology in the colon using high-magnification benchtop FTIR imaging

ArticleLabel-free imaging of cells and tissues is a promising tool to study the molecular alterations for improved cancer diagnosis. In this regard, the vibrational spectroscopic method of FTIR imaging has been employed to study the histo-pathological features and the alterations were correlated to a disease state. The aim of this study was to see if higher magnification images resulting in pixel sizes smaller than the diffraction limit of mid-IR wavelengths with two NA objectives could provide cellular and subcellular resolution of key diagnostic features. To this effect, FTIR spectroscopic imaging has been carried out directly on paraffinized colon tissue sections using a benchtop imaging system consisting of two different IR objectives with a NA of 0.81 and 0.62. The high NA objective (0.81) at a high magnification (63×) provided a pixel size of 0.63 × 0.63 μm2 in comparison to the standard magnification (12×) where the pixel size is 3.3 × 3.3 μm2. The second objective (0.62 NA) at a high magnification (36×) provided a pixel size of 1.1 × 1.1 μm2 in comparison to the standard magnification (7×) pixel size of 5.5 × 5.5 μm2. The spectral images were corrected for paraffin and other spectral interferences using a modified EMSC algorithm and subjected to cluster analysis in order to appreciate the histopathological details. Comparison of the IR cluster analysis results to adjacent haematoxylin and eosin stained tissue sections, which were used as the morphological controls, revealed various levels of histological and cellular organization. Together with large scale features such as the glandular and connective tissue regions, small scale features like goblet cells, interfaces between tissue types especially the peri-cryptal fibroblastic sheath were observed. Noticeable differences between the intracellular mucin and secreted mucin were also observed. However, it appears that high power mid-IR radiation sources would be beneficial, especially when measuring in rapid clinically relevant timescales.This work is part of the MINERVA project (http://www.minerva.eu) which is supported by the European Union’s Seventh Framework Programme (FP7) for research, technological development and demonstration under grant agreement no. 317803

Characterization of colorectal mucus using infrared spectroscopy: a potential target for bowel cancer screening and diagnosis

Biological materials presenting early signs of cancer would be beneficial for cancer screening/diagnosis. In this respect, the suitability of potentially exploiting mucus in colorectal cancer was tested using infrared spectroscopy in combination with statistical modeling. Twenty-six paraffinized colon tissue biopsy sections containing mucus regions from 20 individuals (10 normal and 16 cancerous) were measured using mid-infrared spectroscopic imaging. A digital de-paraffinization, followed by cluster analysis driven digital color-coded multi-staining segmented the infrared images into various histopathological features such as epithelium, connective tissue, stroma, and mucus regions within the tissue sections. Principal component analysis followed by supervised linear discriminant analysis was carried out on pure mucus and epithelial spectra from normal and cancerous regions of the tissue. For the mucus-based classification, a sensitivity of 96%, a specificity of 83%, and an area under the curve performance of 95% was obtained. For the epithelial tissue-based classification, a sensitivity of 72%, a specificity of 88%, and an area under the curve performance of 89% was obtained. The mucus spectral profiles further showed contributions indicative of glycans including that of sialic acid changes between these pathology groups. The study demonstrates that infrared spectroscopic analysis of mucus discriminates colorectal cancers with high sensitivity. This concept could be exploited to develop screening/diagnostic approaches complementary to histopathology.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.WT_/Wellcome Trust/United Kingdom 204909/Z/16/Z/Wellcome Trust (Wellcome)published version, accepted version (6 month embargo), submitted versio

Infrared Spectroscopic Analysis in the Differentiation of Epithelial Misplacement From Adenocarcinoma in Sigmoid Colonic Adenomatous Polyps

This is the final version. Available on open access from SAGE Publications via the DOI in this recordAvailability of Data and Material: The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable requestPurpose: The differential diagnosis of epithelial misplacement from invasive cancer in the colon is a challenging endeavour, augmented by the introduction of bowel cancer population screening. The main aim of the work is to test, as a proof-of concept study, the ability of the infrared spectroscopic imaging approach to differentiate epithelial misplacement from adenocarcinoma in sigmoid colonic adenomatous polyps. Methods: Ten samples from each of the four diagnostic groups, normal colonic mucosa, adenomatous polyps with low grade dysplasia, epithelial misplacement in adenomatous polyps and adenocarcinoma, were analysed using IR spectroscopic imaging and data processing methods. IR spectral images were subjected to data pre-processing and cluster analysis based segmentation to identify epithelial, connective tissue and stromal regions. Statistical analysis was carried out using principal component analysis and linear discriminant analysis based cross validation, to classify spectral features according to the pathology, and the diagnostic attributes were compared. Results: The combined 4-group classification model on an average showed a sensitivity of 64%, a specificity of 88% and an accuracy of 76% for prediction based on a ‘single spectrum’, whilst a ‘majority-vote’ prediction on an average showed a sensitivity of 73%, a specificity of 90% and an accuracy of 82%. The 2-group model, for the differential diagnosis of epithelial misplacement versus adenocarcinoma, showed an average sensitivity and specificity of 82.5% for prediction based on a ‘single spectrum’ whilst a ‘majority-vote’ classification showed an average sensitivity and specificity of 90%. A 92% area under the curve (AUC) value was obtained when evaluating the classifier using the Receiver Operating Characteristics (ROC) curves. Conclusions: IR spectroscopy shows promise in its ability to differentiate epithelial misplacement from adenocarcinoma in tissue sections, considered as one of the most challenging endeavours in population-wide diagnostic histopathology. Further studies with larger series, including cases with challenging diagnostic features are required to ascertain the capability of this modern digital pathology approach. In the long-term, IR spectroscopy based pathology which is relatively low-cost and rapid, could be a promising endeavour to consider for integration into the existing histopathology pathway, in particular for population based screening programmes where large number of samples are scrutinised.National Institute for Health Research (NIHR

A study of organizational versus individual needs related to recruitment, deployment and promotion of doctors working in the government health system in Odisha state, India

Background An effective health workforce is essential for achieving health-related new Sustainable Development Goals. Odisha, one of the states in India with low health indicators, faces challenges in recruiting and retaining health staff in the public sector, especially doctors. Recruitment, deployment and career progression play an important role in attracting and retaining doctors. We examined the policies on recruitment, deployment and promotion for doctors in the state and how these policies were perceived to be implemented. Methods We undertook document review and four key informant interviews with senior state-level officials to delineate the policies for recruitment, deployment and promotion. We conducted 90 in-depth interviews, 86 with doctors from six districts and four at the state level to explore the perceptions of doctors about these policies. Results Despite the efforts by the Government of Odisha through regular recruitments, a quarter of the posts of doctors was vacant across all institutional levels in the state. The majority of doctors interviewed were unaware of existing government rules for placement, transfer and promotion. In addition, there were no explicit rules followed in placement and transfer. More than half (57%) of the doctors interviewed from well-accessible areas had never worked in the identified hard-to-reach areas in spite of having regulatory and incentive mechanisms. The average length of service before the first promotion was 26 (±3.5) years. The doctors expressed satisfaction with the recruitment process. They stated concerns over delayed first promotion, non-transparent deployment policies and ineffective incentive system. Almost all doctors suggested having time-bound and transparent policies. Conclusions Adequate and appropriate deployment of doctors is a challenge for the government as it has to align the individual aspirations of employees with organizational needs. Explicit rules for human resource management coupled with transparency in implementation can improve governance and build trust among doctors which would encourage them to work in the public sector

Understanding community perception and disability weights - A qualitative exploration of reasons associated with values in two states of India

BackgroundHealth state valuation attempts to evaluate health states based on the perception of individuals. The values are used to derive disability weights (DWs) -an important metric for estimation of disability-adjusted life years and thereby calculation of the burden of diseases. Several studies have calculated DWs using different methods of valuation, however, very few have attempted to explore the underlying cause for assigning values to different health states. This study aims to document the perceptions, preferences, and social context in assigning DWs to given health states.MethodsA total of 42 community members and 21 service providers (from public and private sectors) across urban and rural Odisha and Telangana were interviewed between July to September 2018. A face-to-face in-depth interview and a rank ordering technique through card sort exercise was employed to explore reasons and perceptions of individuals in the context of health states using the thematic framework approach.FindingsSix themes emerged through analysis: awareness of the health state, nature of the disease, disease consequences, treatment-related issues, social implications, and case burden. Each theme captured an individual's reason for valuing one health state as different from the other, with differences and/or similarities between community members and service providers.ConclusionOur study provides a comprehensive comparison between contrasting groups of individuals, thereby suggesting mere acceptance of 'experts' reasoning may not always suffice. Further research studies in the future need to be conducted for a better insight into the health perspective of a culturally diverse community. It can also help estimate the burden of disease for decision making and resource allocation in developing countries

Detection of Aβ plaque-associated astrogliosis in Alzheimer’s disease brain by spectroscopic imaging and immunohistochemistry

Recent work using micro-Fourier transform infrared (μFTIR) imaging has revealed that a lipid-rich layer surrounds many plaques in post-mortem Alzheimer’s brain. However, the origin of this lipid layer is not known, nor is its role in the pathogenesis of Alzheimer’s disease (AD). Here, we studied the biochemistry of plaques in situ using a model of AD. We combined FTIR, Raman and immunofluorescence images, showing that astrocyte processes co-localise with the lipid-ring surrounding many plaques. We used μFTIR imaging to rapidly measure chemical signatures of plaques over large fields of view, and selected plaques for higher resolution analysis with Raman. Raman maps showed similar lipid-rings and dense protein cores as in FTIR images, but also revealed cell bodies. We confirmed the presence of plaques using amylo-glo staining, and measured astrocytes using immunohistochemistry, revealing astrocyte colocalisation with lipid-rings. This work is important because it correlates biochemically changes surrounding the plaque with the biological process of astrogliosis