Histological Observations on the Thyroid

Sclare, G (1959) Histological Observations on the Thyroid. MD thesis, University of Glasgow.

Abstract

1. The human thyroid in early and middle foetal life is of similar histological structure to the adult gland. In late foetal life and for a variable period after birth, it often shows a different picture. The colloid content is poor, the epithelium is desquamated, and collapse and disintegration of the acini may lead to the formation of compact cellular masses. Such an appearance is usually attributed to post-mortem degeneration, but is considered by some to represent a state of intense activity or of functional exhaustion. Activation and post-mortem degeneration in the thyroid are difficult to distinguish from one another, as absorption of colloid and collapse of the acini are common to both processes. 2. Examination of 106 thyroids, obtained from stillborn infants and infants dying within the first seven days of life, has shown a great variation in the degree and extent of such changes; the most advanced changes occur in the centre of each lateral lobe, the least advanced at the periphery. Three types of acinus are described: (A) the well-preserved colloid-containing acinus, as seen at other ages, usually lined by cuboidal or columnar epithelium; (B) nuclei displaced towards the lumen by vacuoles in the basal cytoplasm, colloid faint-staining or deeply indented by peripheral vacuolation; (C) desquamated cells in the lumen, colloid faint or absent; at a later stage, disintegration of the acinar wall, and finally solid cellular masses without obvious acinar arrangement. 3. Epithelial desquamation and acinar disorganisation increase little with increasing delay in fixation. The changes do not appear to be related to the maturity of the infant, its sex, the nature of labour, or the cause of death. They occur as frequently in neonatal deaths as in stillbirths, but become less pronounced after the third day of life. 4. Evidence is presented favouring the view that such changes are an expression of increased physiological activity, while the advanced changes represent a state of functional exhaustion. Of the experimental evidence quoted, the most significant facts are the transient phase of colloid depletion and loss of acinar structure in the thyroid of many species not only at "birth but at other times of physiological crisis, and the ability of prolonged thyrotropic hormone administration to bring about similar changes in the thyroid of the adult rat. 5. A study of the thyroid in the newborn guinea pig - one of the animals whose thyroid does not normally undergo any alteration at the time of birth - has shown that changes of this kind cannot be produced by single injections of thyrotropic hormone, nor by allowing the thyroid to undergo post-mortem degeneration. A combination of activation and autolysis came closer to reproducing the disorganisation of acini seen in the human thyroid. While maintaining that the picture in the human neonatal thyroid represents functional hyperactivity or exhaustion, it must be admitted that post-mortem degeneration plays a part in accentuating the changes. (Abstract shortened by ProQuest.).

• Item Type: Thesis (MD)
• Qualification Level: Doctoral
• Keywords: Medicine, Histology
• Date of Award: 1959
• Depositing User: Enlighten Team
• Unique ID: glathesis:1959-79309
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 05 Mar 2020 10:58
• Last Modified: 05 Mar 2020 10:58
• URI: https://theses.gla.ac.uk/id/eprint/79309