Apical cytoplasm

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

Ultrastructural and immunohistochemical studies on non-ciliated cells of the tracheal epithelium of normal, phenobarbital-treated and 3-methylcholanthrene-treated mice.

Abstract: Non-ciliated SER-rich cells of the tracheal epithelium of normal, phenobarbital-treated and 3-methylcholanthrene-treated mice were studied ultrastructurally and immunohistochemically The apical portion of these cells protrudes into the tracheal lumen, especially in the mice treated with the two compounds, and the apical cytoplasm is filled with numerous tubular elements of SER Besides, the non-ciliated cells of 3-methylcholanthrene-treated mice show a strong positive reaction to the antiserum against microsomal cytochrome P-450 of liver These findings support the concept that the non-ciliated tracheal cell may be involved in the metabolism of endogeneous and exogeneous chemical compounds

Rat sperm AS-A: subcellular localization in testis and epididymis and surface distribution in epididymal sperm

Abstract: In this study, we investigated the subcellular compartmentalization of arylsulfatase-A (AS-A) in the testis and epididymis as well as the surface distribution in rat epididymal sperm. Testicular AS-A was compartmentalized specifically to the area underneath the outer acrosomal membrane of the acrosomal granule and to the dorsal aspect of the sperm acrosome. Epididymal AS-A was synthesized in the endoplasmic reticular (ER) network of principal cells and secreted into epididymal lumen as evident by its reactivity in the apical cytoplasm and vesicles therein underneath stereocilia. In clear cells, AS-A reactivity was found throughout the cytoplasmic machineries involved in endocytosis. Surface distribution of AS-A was initially detectable at the concave ridge as early as in sperm of the initial segment (IS). AS-A was additionally localized to the post-acrosomal region in caput (CP), corpus (CO) and cauda (CD) epididymal sperm. The expression levels of surface AS-A gradually increased during sperm transit from IS to CD epididymidis. These results favored the adsorption of AS-A from epididymal fluid onto the sperm surface, rather than shunting from the acrosome as a consequence of capacitation-associated membrane priming.

Morphological alterations of submandibular glands caused by cisplatin in the rat.

Abstract: Cisplatin is a platinum-containing antineoplastic agent, widely used in the treatment of various malignant neoplasms including head and neck cancer. In this study we examined ultrastructural changes of rat submandibular glands (SMGs) after cisplatin treatment. Male Wistar rats aged 8 weeks were used in the experiments. Cisplatin was injected intraperitoneally into the rats (5 mg/kg/day) for three consecutive days. After 1, 3, 5, and 7 days, the SMGs were removed and observed under an electron microscope. The terminal portion of the SMG is seromucosal. Acinar cells contained a parallel array of rough-surfaced endoplasmic reticulum in the basal cytoplasm, and the apical cytoplasm was filled with homogeneous secretory granules. Vacuolation of cells was observed on the first day after cisplatin treatment. On the third and fifth days, the rough-surfaced endoplasmic reticulum showed an irregular arrangement. Mitochondrial swelling, and the presence of autophagolysosomes was also confirmed. On the seventh day, the damage to organelles began to decrease and the SMG exhibited a tendency towards improvement.

Light- and electron-microscopic radioautographic study of glycoprotein secretion in the granular duct of the submandibular gland of the male mouse.

Abstract: L-3H-fucose was injected intravenously into adult male mice, after which, at different time intervals, the submandibular glands were removed and processed for light-and electron-microscopic radioautography. This radio active hexose was taken up by newly synthesized glycoproteins in the cells lining the granular ducts which were maximally labeled at 4 h after injection. Between 4 and 72 h the amount of labeled glycoproteins decreased moderately indicating that these macromolecules undergo a slow renewal. The main subcellular site of incorporation of 3 H-fucose into glycoproteins was the Golgi apparatus. From this organelle labeled glycoproteins were transferred to small secretory granules (diameter up to 1.0 μm) located not only near the Golgi region but also throughout the apical cytoplasm. At 1 h after injection the concentration of label reached a maximum in the small secretory granules and labeling of medium (diameter between 1.1 and 2.0 μm) and large (diameter over 2.0 μm) granules was very low. At this postinjection interval the secretion product inside the lumen of the duct was already labeled. Between 1 and 72 h after injection the concentration of radioactivity in the small secretory granules decreased intensely while increasing in the medium and in the large ones. The concentration of fucose label reached a maximum in the medium secretory granules at 24 h and in the large ones at 72 h after injection. Additional experiments using mice previously injected with 4 intraperitoneal doses of 3H-fucose given 3 h apart demonstrated that the large granules undergo a very slow renewal. Some were found to be labeled as long as 28 days after administration of 3H-fucose. Recorded in this latter series of experiments was the labeling pattern of dense bodies that were regularly visualized in the cells lining the granular ducts. Their significance in the secretory process is discussed. In conclusion, newly synthesized glycoproteins are transferred from the Golgi apparatus to small secretory granules which carry a readily releasible pool of these macromolecules to the lumen of the duct. The small secretory granules also transfer newly synthesized glycoproteins to medium and large secretion granules which store a pool that is released very slowly. This characterizes the large secretory granules as the intracellular sites of storage of secretion products. The results of this investigation were correlated with the knowledge about the chemical composition of the different macromolecules that are known to be synthesized by the secretory cells of the granular ducts of the submandibular gland of the mouse.