Differences in the ultrastructure of the submandibular glands of baboon and Rhesus monkey revealed by the use of different fixatives.

Submandibular glands of adult baboon and Rhesus monkeys were compared after different methods of fixation. In both species, serous acinar cells outnumber mucous acinar cells. In the baboon, serous cells contain secretory granules showing dense cores, moderately dense crescents, and flocculent material. In mucous cells, secretory granules vary in appearance from amorphous to highly ordered depending on fixation. In the Rhesus monkey, serous cells contain the same 3 components of secretory granules as in the baboon. Additionally, a fourth component is represented by a layer of electron-dense material between the crescent and flocculent material. Mucous cells contain electron-dense granules when fixed in Millonig's buffered fixatives, but when Clarke's or Sorensens' buffer is used the granules resemble more typical mucous granules. Duct systems of the two species are similar, but differ mainly in that large foci of glycogen are present in the striated duct cells of the Rhesus monkey.

Correlated TEM, SEM, and histological observations of filiform papillae of the cow tongue.

The ultrastructural and histological characteristics of the filiform papillae of the cow tongue are described. These large, conical papillae display a fully keratinized external projection, which demonstrates a dominant hard keratin core partially ensheathed by soft keratin. This biostructure differentiates from a dominant posterior cell line, leading to the hard keratin core, and a thinner anterior cell line which, with contributions from an interpapillary cell line, appears responsible for an attenuating sheath of soft keratin around the hard keratin core. The hard keratin cell line differentiates from cells devoid of keratohyalin granules (KHG), which are rich in thick bundles of tonofilaments. The soft keratin cell line differentiates from cells containing both eosinophil and basophil KHG and dispersed tonofilaments. The bovine filiform papilla also appears similar in biostructure to the mammalian hair shaft and the 'filiform hairs' of the rat penis.

Filiform papillae of cat tongue.

A pronounced species variation in the organization of filiform papillae has been observed. Preliminary histologic studies of cat tongue revealed marked regional variations in size, shape and organization of filiform papillae. Therefore, a correlated light microscopic, transmission and scanning electron microscopic study of tissue samples of representative areas of the cat tongue was undertaken for further elucidation. Results showed that filiform papillae on the tip of the tongue were short and exhibited several conical processes from the base of each papilla. In contrast, filiform papillae in the midportion of the dorsum of the tongue consisted of a large mound with a single sharp spinous process projecting posteriorly. In the region of the vallate papillae, the filiform papillae were shorter and more conical than those on the midportion of the tongue. In addition, keratohyalin granules in filiform papillae were comprised of an eosinophil spheroid with small basophil attachments.

Effects of isoproterenol on the ultrastructure of pig parotid gland.

Following chronic administration of isoproterenol, the parotid glands of the domestic pig were removed and studied with transmission electron microscopy. Acinar cells were markedly altered, whereas ductal elements were apparently unchanged. A notable hypertrophy of Golgi membranes was observed. In addition, electron-dense bodies located near the Golgi membranes were more numerous after isoproterenol administration.

A correlative light microscopic, transmission and scanning electron microscopic study of the dorsum of human tongue.

The dorsum of the human tongue has three types of papillae, filiform, fungiform and circumvallate. Some investigators have studied these by light and transmission electron microscopy. Since knowledge of the morphology through studies by scanning of the morphology through studies by scanning electron microscopy (SEM) is scant, this investigation was started with the purpose of studying human tongues at different ages. One fetal tongue and portions of three tongues from newborns were removed. Additional specimens were biopsied from the anterior region of three adult tongues. Samples were processed routinely for light microscopy, transmission electron microscoy (TEM) and scanning electron microscopy (SEM). Two distinct features were evident on the fetal tongue. The first was that the surface epithelial layer of the tongue appeared to be periderm. The second was that fungiform papillae began their development earlier than filiform. At birth, the putative periderm had disappeared and a few filiform papillae were observed. On the adult tongue, filiform papillae were numerous and were comprised of two cell populations. One cell population contained numerous keratohyalin granules (KHG). The KHG were two types, eosinophilic and basophilic. Ultrastructurally, the eosinophilic granules were less electron dense and larger in size than the basophilic KHG.

Histological and ultrastructural observations of eosinophilic keratohyalin granules in filiform papillae of pig tongue.

Cells in filiform papillae of pig tongue possess distinct granules that stain with eosin but little or none with hematoxylin. This eosinophilia differs from the classically described basophilia of keratohyalin granules as is described in skin and keratinized oral mucosa of many species. At the ultrastructural level, electron-dense granules were observed in the cytoplasm and occasionally in the nuclei of cells within the papillae. The granules were round, oval or irregular in shape and varied in size and density. The ultrastructural characterization of these eosinophilic granules is the first reported in the literature.

A correlative light microscopic, scanning and transmission electron microscopic study of the dog tongue fiiform papillae.

Recent studies in our laboratories have suggested that the epithelial cells of the dog tongue filiform papillae are organized into clearly delineated epithelial cell columns within the papillae. However, the contributions of these epithelial cell columns to the surface morphology of the dog papillae was unknown. Therefore, the objective of this investigation was to conduct a correlative scanning electron microscopic (SEM), transmission electron microscopic (TEM) and light microscopic (LM) examination of these epithelial cell columns in dog filiform papillae to study their contribution to tongue surface morphology. By scanning electron microscopy the numerous conical filiform papillae observed on the anterior two-thirds of the dog tongue were curved posteriorly. In addition to these primary papillary projections, the papillae exhibited secondary conical projections. A number of conical tertiary projections were also located anteriorly at the base of the papillae. Correlative histologic studies revealed anterior and posterior epithelial cell columns for the primary projections, lateral columns for the secondary projections and 5-7 smaller cell columns corresponding to tertiary projections seen by SEM. Thus, it appears that there is a complex organization of the proliferating and differentiating epithelial cells in dog filiform papillae. These epithelial cell columns exist as distinct units and correspond to the various surface projections.

Histological observations on the effects of isoproterenol on regenerating submandibular glands of the rat.

The effect of isoproterenol (IPR) on acinar cell mitoses was studied in regenerating submandibular glands of the rat following partial extirpation. In controls, mitoses of acinar cells were markedly higher on the cut surface (reactive zone) than in the remainder of the gland through 10 ds post-operation. In experimental animals by 5 ds, a burst of mitoses of acinar cells was seen in all areas of the gland except the reactive zone. In the reactive zone, IPR appears to suppress or inhibit the induced mitoses seen in controls.