Ultrastructural pathology of human gastrointestinal tumours

Al-Yassin, Tariq Mohamed (1976) Ultrastructural pathology of human gastrointestinal tumours. PhD thesis, University of Glasgow.

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Abstract

This thesis consists of an ultrastructural study of 129 neoplasms of the human alimentary tract, included are observations oh 39 samples of control human tissues, including hitherto poorly described features of the normal human oesophagus. All tissues examined were from freshly fixed biopsy or resection specimens. The techniques used were those of conventional transmission electron microscopy. Some limited studies employed ultracytochemical methods to demonstrate carbohydrate and acid phosphatase activity. In these studies, X-ray microanalysis was also employed to confirm the identity of the reaction product. The normal squamous epithelium and submucosal glands of the human oesophagus were investigated in detail. The fine structure of squamous epithelium, was found to be similar to that of non keratinized epithelium in other situations. Certain features not previously noted included the occurrence of occasional cilia, intracytoplasmic desmosomes and nuclear bodies. Langerhans cells, which have been described in the epidermis and in other squamous locations, were also observed in oesophageal squamous mucosa. The submucosal glands were comparable to the labial salivary glands. Ultrastructural investigation of well differentiated squamous cell carcinoma of the human oesophagus revealed various similarities to, and aberrations from, the normal patterns of oesophageal squamous cell differentiation. Particular features of note included frequent intracytoplasmic desmosomes and curious thick-walled vesicles. Langerhans cells v/ere observed in these tumours, as in the normal mucosa. The normal gastric mucosa was studied as a control material. There were no particular features of note, the finding corresponding to the published literature. The cases of primary gastric carcinoma fall into two main groups, those with mucous secretion granules identical to the granules of gastric mucous cells and those without mucous secretion granules. There were other fine structural details which served to distinguish these two groups. In cases of secondary gastric carcinoma, some bore a close structural resemblance to equivalent primary gastric tumours and contained mucous secretion granules identical to those of gastric mucous cells, while others contained no mucous granules. Metastatic signet ring cell carcinoma was similar in many respects to previous reports of primary signet ring cell carcinoma. However, among the observed structural differences were the occurrence of tubulovesicular structures similar to those of normal gastric parietal cells and of frequent intracytoplasmic desmosomes. Gastric carcinoma was particularly distinguished by the presence: of a variety of structurally aberrant organelles. The most poorly differentiated tumours retained the adhesion specialisations typical of epithelial cells, in contrast to the findings in gastric lymphoma, in which desmosomes were absent. The normal colonic morphology as studied in this work showed no particular features at variance with previous reports. The villous papillomas and colonic carcinomas examined displayed the fine structural features in common with the immature cells of the lower one third of the colonic crypt. The aggregates of dark cells in villous papilloma had features reminiscent of various cell types associated with fluid and electrolyte transport in other sites. Two distinctive features of primary well differentlated colonic carcinoma were the occurrence of an aberrant tubular form of granular endoplasmic rectuculum and the presence of doughnut-shaped carbohydrate - rich inclusions, possibly representing a secretory product. Various distinctive intranuclear and intracytoplasmic inclusions were observed in the course of this work, mainly in neoplastic cells in different sites. These had not previously been described in either normal or neoplastic cells of the human alimentary tract. The possible diagnostic relevance of such features is discussed. Using a periodic acid thiocarbohydrazide silver proteinate technique a carbohydrate component was demonstrated in various sites in the normal and neoplastic tissues studied. In most normal and neoplastic cells of the human alimentary tract, acid phosphatase was confined to the lysosomes. However, in both normal squamous epithelium and well differentiated squamous cell carcinoma, acid phosphatase activity was also found in the intercellular spaces, although the membrane-coating granules were negative. The reaction products of both of these cytochemica.1 procedures were examined by x-ray microanalytical techniques.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: P G Toner
Keywords: Pathology, Oncology
Date of Award: 1976
Depositing User: Enlighten Team
Unique ID: glathesis:1976-74146
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 23 Sep 2019 15:33
Last Modified: 23 Sep 2019 15:33
URI: http://theses.gla.ac.uk/id/eprint/74146

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