The ultrastructure of sheep pulmonary adenomatosis

Abstract

Eight sheep with pulmonary adenomatosis provided lung tissues for a study of the ultrastructure of the lesions. Abnormalities observed in cuboidal or columnar tumour cells were an enlarged polymorphic nucleus, a multiple and enlarged Golgi-apparatus, an increase in free ribosomes, dilatation of the endoplasmic reticulum into vacuoles and large lacunae, and vesicles filled with secretion. Cells were often irregularly shaped and had numerous microvilli on their free surface. Sometimes desmosomes were observed between adjacent tumour cells.

The fine structure of the adenomatous cells was, in general, similar to that in carcinomas in man.

No intracellular inclusion bodies were seen. In one sheep chlamydia were demonstrated and in another virus-like particles were observed; there was no evidence that these structures were of aetiological significance.