Apical cytoplasm

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

Aural polyp associated with cryptosporidiosis in an iguana (Iguana iguana)

Abstract: Figure 2. Electron micrograph. Aural polyp; green iguana. Pseudostratified columnar epithelial cells with numerous cryptosporidial trophozoites (arrowheads). Bar 5 2 mm. Cryptosporidiosis is well recognized as a gastroenteric pathogen in many mammalian species, as both an enteric and respiratory pathogen in domestic fowl, and as a gastric pathogen in several reptilian species.2,3,5 This report describes the first documented case of cryptosporidiosis in a green iguana (Iguana iguana) and an association of the organism with an inflammatory polyp within the middle ear canal, an anatomic location where Cryptosporidium has not been previously recognized. An adult female green iguana was presented because of a protruding right tympanic membrane; the protrusion had been present for approximately 2 weeks. The referring veterinarian had detected an irregular 1.0–1.5-cm-diameter firm mass that filled the right tympanic cavity, had surgically excised the mass, and had submitted the tissue, fixed in 10% neutral-buffered formalin, for diagnostic evaluation. The tissue was routinely processed for histopathology. An accompanying swab of the mass was submitted for routine aerobic bacteria culture; no bacteria were isolated from the swab. Histologically, the mass consisted of a core of dense fibrous connective tissue covered by hyperplastic pseudostratified columnar epithelium with scattered mucous goblet cells. There were moderate numbers of heterophils within the connective tissue just beneath the epithelium, with some exocytosis of heterophils. Few lymphocytes and plasma cells were scattered through the connective tissue. Along the outer ciliated border of the epithelium, there were numerous 2–3mm-diameter basophilic protozoal organisms associated with the apical cytoplasm; these organisms were consistent with Cryptosporidium (Fig. 1).2 Tissues were postfixed in glutaraldehyde and routinely prepared for transmission electronmicroscopy. Many epithelial cells contained one or more spherical protozoa beneath the host cell plasma membrane; the cell membranes had lost their cilia in the areas associated with the organisms (Figs. 2, 3). Most of the organisms were consistent with trophozoites, although occasional forms resembling schizonts and gametocytes were also present.2 Trophozoites were an average of 2.0 3 2.5 mm, had a single prominent nucleus and a distinct feeder organelle in the zone of attachment to the host cell, and were surrounded by a parasitophorous vacuole bounded by a plasma membrane (Fig. 3). This is the first report of Cryptosporidium in an iguana,

Preferential uptake of soluble antigen by respiratory tract epithelium overlying bronchus-associated lymphoid tissue in the rat.

Abstract: Soluble protein antigen (Horseradish peroxidase — HRP) administered to rats intratracheally is predominantly phagocytosed by alveolar macrophages and Type-II pneumonocytes. A proportion, after localization on the lumenal surface of the bronchiolar epithelium is transported across the epithelium via the apical cytoplasm and the intercellular space to the region of the basement membrane. The rate of transfer is faster in the epithelium closer to areas of BALT than elsewhere and in these areas there is further significant penetration below the basement membrane into the BALT tissue to facilitate the contact of antigen and of lymphoid cells. No evidence of alveolar macrophage re-entry to the lymphatic system after phagocytosis of HRP could be seen.

Expression and Localization of Aquaporins in the Kidney of the Musk Shrew (Suncus murinus)

Abstract: Expression and localization of members of the aquaporin (AQP) family (AQP1, 2, 3, 4, and 5) in the kidney of the musk shrew (Suncus murinus) was examined by immunohistochemistry AQP1 was expressed in the proximal tubules and in the thin limb of the loops of Henle AQP1 was the only water channel expressed in the proximal nephron examined, indicating that AQP1 may be an independent water transporter in the proximal nephron AQP2 and AQP5 were localized to the apical cytoplasm of the cortical to medullary collecting duct (CD) cells and AQP3 and AQP4 were localized to the basal aspect of the cortical to medullary CD cells AQP3 expression was weaker in the cortical cells compared with the medullary cells, whereas AQP4 was strongly positive throughout the CD These indicate that the CD is the main water reabsorption segment of the nephron and is regulated by AQPs Indeed, apical water transport of CD cells of the musk shrew may be controlled by both AQP2 and AQP5 The characteristic expression pattern of the AQPs in this animal provides a novel animal model for elucidating the regulation of water reabsorption by AQPs in the mammalian kidney