Effects of vitamin A deficiency on ultimobranchial tissue in the rat thyroid

While investigating the intrinsic vasculature of the canine thyroid gland, atypical thyroid follicles were observed histologically, arising from a postnatal thyroid cyst of unknown origin, in stained sections of a male, 1-year-old, mesaticephalic dog. The animal was anesthetized, bled, killed by injection of Toxital directly into the heart, and perfused with 10% buffered neutral formalin solution. The thyroid tissue was fixed, embedded in paraffin, sectioned serially, and mounted on glass slides. Concordant with descriptions in the literature, this structure appeared to be a postnatal ultimobranchial-like cyst with direct connections to both ultimobranchial and mixed follicles. Seemingly, this observation has never been reported previously in the canine and would lend support to the hypothesis that ultimobranchial-like cysts may give rise to these atypical follicles. However, the authors are not totally convinced that all such thyroid cysts are solely ultimobranchial in origin. A review of the literature supporting this contention is discussed.

Section: Discussionmentioning

confidence: 99%

Atypical thyroid follicles arising from an ultimobranchial-like cyst in a postnatal canine thyroid gland

Booth¹,

Ghoshal²

1978

“…One is similar to a squam ous cyst and has mainly been found in the rat [ Van Dyke, 1944, 1945Axelrad and Leblond, 1955;Ishikawa, 1965;Calvert and Isler, 1970;Woilman and Neve, 1971a, b;Neve and Woilman, 1971;Calvert, 1972aCalvert, , b, 1975Krupp, 1972;Christov et al, 1973;Petko, 1975] and possibly also in the sheep [ Van Dyke, 1945]. The other type is a folli cle containing a heterogeneous cell popula-tion.…”

Section: Introductionmentioning

confidence: 87%

Fine Structure of the Second Kind of Thyroid Follicles in Mature Guinea Pigs

Juhl¹

1981

The second kind of follicle (S-follicle) is in mature guinea pigs a morphologically heterogeneous structure located in the central part of the upper two-thirds of the thyroid lobe. An S-follicle may appropriately be divided in an upper, a middle, and a lower part. This paper deals with the ultrastructure of the upper tubular part and the middle part. The latter is further subdivided in an irregular follicle and a distended follicle. In the tubular part a single cell type, termed the S-follicle cell, is dominating. This cell is most often arranged in a single layer and is characterized by an indented nucleus and by presence of pinocytose vesicles and hemidesmosomes along the basal cytoplasm membrane. In addition, C cells are frequently found. In the irregular follicle five different cell types are noticed: S-follicle cells, dark fibrillar cells, granulated cells, ciliated cells, and C cells. The S-follicle cells display an ultrastructure similar to those in the tubular part but are frequently arranged in two or more layers. Both the tubular part and the irregular follicle are surrounded by connective tissue. In the distended follicle, however, contact areas to thyroid follicles are found. Adjacent to these contact areas, cells with an ultrastructure similar to that of thyroid follicle cells proper are encountered in the wall of the S-follicle. This observation suggests that the distended part of an S-follicle in mature guinea pigs might be regarded as a kind of mixed follicle. The origin of thyroid follicle cells proper in the wall of the S-follicle is briefly discussed.

“…Politzer [1936] and Norris [1937] believed that the UBB converts into thyroid parenchyma. It has been reported that in the guinea pig [Klapper, 1946], mouse [ Wetzel and Wollman, 1969] and rat Wollman and Neve, 1971;Krupp, 1972;Calvert, 1975] the UBB gives rise to ultimobranchial cysts. Cordier et al [1976] believed that these cysts in dwarf mice are the endodermal remnants of the UBB after the migration of parafollicular cells.…”

Section: Unusual Folliclesmentioning

confidence: 99%

Thyroid Calcitonin Cells and Unusual Follicles in the Fox

Srivastav¹,

Swarup²

1982

The thyro-parathyroid complex of foxes was cut into serial sections. For demonstration of calcitonin (C) cells the sections were stained by hematoxylin and eosin, PAS-hematoxylin, Davenport’s silver impregnation and lead hematoxylin. The C cells are oval and rounded in shape and unevenly distributed. The isthmus and the parathyroid glands are completely devoid of C cells. Certain unusual follicles are seen in the thyroid of the fox.