Browsing by Author "Shepherd, Neil A."

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    Correlating histology and spectroscopy to differentiate pathologies of the colon
    (2012-09-25) Carey, Duane; Shepherd, Neil A.; Kendall, Catherine; Stone, Nick; Breckon, Toby P.; Lloyd, Gavin Rhys ; Xianghua, Xie
    The techniques and procedures associated with histology are, in most cases, suitable for the diagnosis of colonic carcinomas. However, in cases such as epithelial misplacement the morphology of a stained tissue sample is homologous to that of cancer. This can lead to patients being misdiagnosed and undergoing unnecessary surgery. To prevent this surgery we suggest that the epithelium of tissue samples be examined using infrared (IR) spectroscopy. In this study, IR maps of tissue sections were registered to standard histology images so that epithelial specific spectra could be collected. The differences between these spectra were explored by using Principal Component Analysis (PCA). This paper provides a novel protocol detailing how histology specific spectra can be collected. The potential usefulness of these spectra is demonstrated through the separation of epithelial misplacement cases and colonic carcinomas within PCA space.
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    The development of novel adjuncts to aid in the diagnosis of Epithelial Misplacement
    (Cranfield University, 2013-06) Carey, Duane Owen; Kendall, Catherine; Breckon, Toby P.; Shepherd, Neil A.; Stone, Nicholas
    Epithelial Misplacement (EM) is a benign phenomenon that occurs within polyps most commonly associated with the sigmoid colon. It is brought about because of the colons convulsive nature and this forces a polyps surface epithelium into its submucosa and also causes bleeding. This is problematic as the Bowel Cancer Screening Programme (BCSP) uses positive Faecal Occult Blood (FOB) test results to identify patients that require pathological review. As EM polyps bleed, they get selected for assessment and this results in them being sectioned and stained. In these cross sections, submucosal glandular tissue will be found that looks like it has formed due to metastatic mechanisms. This can lead to ambiguous diagnoses that will cause some patients to undergo unnecessary surgery. It is postulated that this can be prevented if the continuity of the EM samples could be measured. This is because only in the EM cases will the submucosal epithelial tissue remain in continuity with the surface. To test this, volumes representative of 9 samples of cancer and 13 cases of EM were segmented and their number of 26 three dimensional (3D) connected components were recorded. These were used with the 99% confidence limits of the two tailed Mann Whitney U Statistic and tested the null hypothesis that the cancer cases were as connected as the EM samples. In this instance, no significant differences were found and so the benefit of measuring the connectivity of these pathologies is questionable. It was because of this that Immunohistochemical (IHC) alternatives were considered. It was found that Collagen IV antibody staining correctly differentiated nine samples of EM from ten cases of cancer. The Mann Whitney U Statistic found this to be highly significant, p < 0.001, and future investigations should concentrate on automating this analysis. Although, Collagen IV provided a good classification it relied upon the subjective assessment of a pathologist. Therefore, the use of epithelial specific IR spectra was also investigated and this enabled the eleven EM and nine cancer cases that were investigated to be accurately classified 80% of the time upon cross validation. The collection of epithelial specific spectra relied upon a novel digital staining technique that has much application within future research. This study demonstrates that the intermodal registration of complementary modalities is of benefit to the disease classification problem. This technique has potential to be used in the correct identification of EM but more work is required.
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    The study of molecular markers for the progression of Barrett's Oesophagus to adenocarcinoma to identify markers that can be used as diagnostic tools.
    (Cranfield University, 2002-05) Cadd, Verity Anne; Warner, P.; Barr, H.; Shepherd, Neil A.
    Barrett's oesophagus is a complication of gastro-oesophageal reflux disease and is the single most important predisposing factor for the development of adenocarcinoma of the oesophagus. New molecular markers are needed for early diagnosis and to monitor disease progression. Telomerase is a ribonuclear protein with reverse transcriptase activity, which uses its own RNA component as a template for the addition of telomeric repeats to the end of chromosomes. Telomerase activity has been studied during the neoplastic progression of Barrett's oesophagus using a TRAP based ELISA technique, which found telomerase to be reactivated early during . disease progression. A non-isotopic method of in situ hybridisation for the detection of the RNA component of telomerase has also been successfully developed. Plasminogen activation is an inducible extracellular proteolytic system involved in the regulation of cellular interactions and invasion. The components of the urokinase-type Plasminogen Activator system have been fully investigated during the progression of Barrett's oesophagus to adenocarcinoma utilising immunohistochemistry and ELISA techniques. Changes in the expression of this invasive phenotype were found to occur late during disease progression in malignant tissues. Two-oesophageal cell-lines have been characterised using molecular biological techniques to detect a range of molecular markers to produce ex vivo models of oesophageal adenocarcinoma and oesophageal squamous cell carcinoma. In order to assess the effects of bile salts and acidity on oesophageal tissues these celllines were then utilised as ex vivo models. Exposure to acidic conditions both alone and with bile salts altered the morphological appearance of the cells and disrupted adhesion molecules in the cellular membrane. Investigations into both telomerase reactivation and the plasminogen activator system have provided new information concerning the nature and timing of molecular changes during the Barrett's metaplasia/dysplasia/ adenocarcinoma sequence.