A Transmission Electron Microscopic Study of Some Bronchiolar-Alveolar Reactions in Sheep and Cattle

Periathamby, Loganathan (1989) A Transmission Electron Microscopic Study of Some Bronchiolar-Alveolar Reactions in Sheep and Cattle. MVM(R) thesis, University of Glasgow.

Abstract

The two main objectives of this thesis were firstly to study the morphological features of the alveolar macrophages (AM's) in normal sheep and in normal cattle and secondly to study AM's in sheep pulmonary adenomatosis (SPA) and in calves infected with the lungworm, Dictvocaulus vivioarus. in order to compare their morphological characteristics in the two diseases. The history and development of the transmission electron microscope (TEM)are outlined in Chapter 1. The use of the TEM in diagnostic pathology and research into animal and human diseases is also discussed with some examples relevant to studies in animals. A review of the ultrastructure of the cell types in the normal bronchiolar and alveolar epithelium in sheep and cattle is presented in Chapter 2. The AM in normal lungs in introduced and considered in this chapter. The structure of the lungs of normal sheep were studied to provide comparisons for subsequent examinations of SPA lungs at both light microscopic and electron microscopic levels. This work is reported in Chapter 4. Ciliated cells and Clara cells were identified in the bronchiolar epithelium while type I and type II pneumonocytes were recognised in the alveolar epithelium. The morphology of these different cells were described. Ewes with SPA were studied by light microscopy (LM) and TEM. The results confirmed that the proliferating tumour cells were due to the transformation of the type II pneumonocytes. No viral particles were identified in the cases examined. The AM's were consistently found in the alveolar lumen and their morphological characteristics revealed that they were activated. These activated AM's could be classified into two groups, based on their morphological features. The possible roles of the AM's in the pathogenesis of SPA is discussed. The histologic and ultrastructural appearance of cattle lungs were studied and compared with the lungs of calves that had been infected with lungworms; this is reported in Chapter 5. Ciliated cells and Clara cells were found in the bronchiolar epithelium while type I and type II pneumonocytes were noted in the alveolar epithelium. Alterations were observed both in the cell types of the bronchiolar epithelium and in the alveolar epithelium in calves with lungworms. In the bronchiolar epithelium, moderate to severe degenerative changes were recognised in the Clara cells and there was a loss of cilia from the ciliated cells. There was severe degeneration and type II pneumonocyte proliferation with hydropic swelling of the cytoplasm of the type I pneumonocytes. Inflammatory cells were a frequent finding in the bronchiolar and alveolar lumen. Interalveolar septa were markedly thickened in many cases. Alveolar macrophages were commonly found in the inflammatory exudate. They were similarly activated as the AM's in SPA. Morphologically, only one group of AM's could be identified. Some aspects of the cell kinetics of the lung, in particular the AM's, are discussed in Chapter 6. The morphological differences of the AM's in the two diseases are presented and discussed at the end of this chapter.

• Item Type: Thesis (MVM(R))
• Qualification Level: Masters
• Keywords: Veterinary science
• Date of Award: 1989
• Depositing User: Enlighten Team
• Unique ID: glathesis:1989-77914
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 30 Jan 2020 15:48
• Last Modified: 30 Jan 2020 15:48
• URI: https://theses.gla.ac.uk/id/eprint/77914