Apical cytoplasm

About: Apical cytoplasm is a research topic. Over the lifetime, 1080 publications have been published within this topic receiving 36131 citations.

Ultrastructure and histochemistry of the vas deferens of the salamander Rhyacotriton olympicus: adaptations for sperm storage.

Abstract: The vas deferens of the salamander Rhyacotriton olympicus is composed of (1) a peritoneal epithelium, (2) connective tissue with fibroblasts, melanophores, circular smooth muscle, capillaries, and unmyelinated nerves within a collagenous matrix, and (3) an inner layer of cuboidal epithelium partially covered by ciliated squamous cells at the lumen. The lumen and apical cytoplasm of both epithelial cell types contain strongly PAS-positive granules. The cuboidal cells contained numerous swollen rough endoplasmic reticulum cisternae, mitochondria, and apical dense granules suggesting a high degree of secretory activity possibly involved in sperm maintenance. Fewer mitochondria, rough endoplasmic reticula, and granules in squamous cells suggest less secretory activity. Squamous cells may protect the cuboidal cells from possible abrasion by sperm masses and/or their cilia may aid in distributing secretory products in the lumen.

Histochemical and Immunohistochemical Analysis of the Stomach of Rhinella icterica (Anura, Bufonidae)

Abstract: The stomach of Rhinella icterica was analyzed at light microscopy, employing histochemical techniques, lectin histochemistry, and immunohistochemistry for identifying enteroendocrine cells (EC). Although the stomach was composed of fundic and pyloric regions, its wall is formed by mucosa, submucosa, muscularis, and serosa. The mucosa was lined by a simple columnar mucous epithelium, supported by loose connective tissue. Several tubular, simple glands were composed of mucous neck cells, containing oxynticopeptic cells and EC cells. The mucous neck cells were rich in neutral glycoconjugates. The oxynticopeptic cells were predominant in fundic glands, exhibiting weaker alcianophilic reaction at their apical cytoplasm. Serotonin (5-HT) immunoreactive (IR) cells occurred throughout the entire stomach, preferentially located among mucous cells at upper part of the fundic glands. The muscularis mucosae, formed of smooth muscle, separated the mucosal layer from the submucosa, both of which were constituted by loose connective tissue, but without glands. Lymphoid modules occurred in the mucosa at the boundary at the stomach and the gut. In addition, the muscularis was constituted by two sublayers, the circular internal and the longitudinal external, being recovered by the connective tissue of the serosa.

Modulation of apoptosis by starvation: morphological and biochemical study of rat intestinal mucosa.

Abstract: Morphology at light and electron microscopic levels, expression and activation of transglutaminase and DNA fragmentation at internucleosomal sites were used as markers to study the effect of starvation on the apoptosis of small intestinal epithelial cells. The cells entering apoptotic programme in well-fed animals undergo many morphological changes in apical cytoplasm involving alterations in actin cytoskeleton organisation which may cause a discharge of microvilli. Some free floating cells in the intestinal lumen show characteristics of apoptotic cell death, e.g. shrinkage of cell and peripheral condensation of chromatin, while mitochondria and lysosomes remain unchanged. Apoptotic bodies are also seen in scanning electron micrographs. During progressive starvation, epithelial cells do not enter the apoptotic cell death programme. Biochemical markers for apoptosis such as increased transglutaminase activity and DNA fragmentation are clearly discernible in normally fed animals. The percentage of cells labelled immunohistochemically by antibody against transglutaminase decreased during starvation while DNA fragmentation was absent. The exact mechanism for suppressing apoptosis in intestinal cells under starvation is not known. However, the data presented here support the existence of such a regulatory process.

Immunohistochemical localization of thyroid hormone in rat thyroid gland.

Abstract: Direct and indirect immunofluorescence techniques were used to localize the thyroid hormones triidothyronine (T3) and thyroxine (T4) in adult rat thyroid gland. Optimum dilutions of the antisera were established and four tissue fixatives were investigated for usefulness in this technique. Use of antibodies specific for either T3 or T4 resulted in brilliant fluorescence in the colloid pools and apical cytoplasm of follicular cells. In all cases, the adjacent parathyroid gland was devoid of fluorescence. This report demonstrates that these dipeptide hormones can be localized by using immunofluorescence techniques.

Lumen Formation During Development of the Rat Submandibular Gland

Abstract: This study utilized electron microscopy and enzyme histochemistry to examine the morphological steps associated with the formation of a lumen in the end-buds of the embryonic rat submandibular gland. Lumen formation involved the development of junctional complexes by the central cells of the end-buds late on the 16th day of gestation. These junctional complexes established the apical domains of the presecretory cells, and cytofilament aggregates were observed beneath the presumptive luminal plasma membranes. This central area of the end-buds showed strong myosin ATPase activity, presumably associated with the cytofilaments. On the 17th day of gestation, small lumina appeared at the sites delineated by the junctional complexes. The myosin ATPase activity appeared to surround the newly opened lumina. By the 18th day of gestation, microvilli were seen projecting into the lumina, and secretory granules were often visible in the apical cytoplasm near the luminal plasma membranes of the early secretory cells. M...