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Apical cytoplasm
About: Apical cytoplasm is a research topic. Over the lifetime, 1080 publications have been published within this topic receiving 36131 citations.
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TL;DR: When the esterase activity was compared histochemically in rats, dogs and monkeys, it was found that the activity was extremely weak in dog intestine, providing an explanation for the fact that intact pivampicillin was detected in the portal venous blood only in dogs after oral administration.
Abstract: The intestinal absorption and the site for hydrolysis of pivampicillin were compared with those of ampicillin by in situ ligated loop method in rats, using the radioactive compounds labeled at the phenylglycyl and the oxymethylene moieties. It was shown that pivampicillin is well absorbed from all parts of intestine, while ampicillin is absorbed from a more limited part of intestine. Pivampicillin was found to be rapidly transferred from the lumen into the intestinal wall as an intact ester and was hydrolyzed rapidly in the tissue. Ampicillin thus formed appeared to be transitorily accumulated in the tissue before being transferred into the portal venous blood gradually. Ampicillin was absorbed slowly without any accumulation in the intestinal wall. Microautoradiography of pivampicillin-14C in the intestine demonstrated that the radioactivity is accumulated in the epithelial cells in a high concentration. Histochemical and cytochemical detection of non-specific esterase revealed that a high activity is located specifically in the epithelial cells of villi and that the activity is localized in the membranes of endoplasmic reticulum as well as the cytoplasm, while there was almost no activity in the microvilli and terminal web region. It is considered therefore that pivampicillin is penetrated into the epithelial cells without any cleavage of the ester group and hydrolyzed by non-specific esterase in the apical cytoplasm of the cells. When the esterase activity was compared histochemically in rats, dogs and monkeys, it was found that the activity was extremely weak in dog intestine, providing an explanation for the fact that intact pivampicillin was detected in the portal venous blood only in dogs after oral administration. A possible relation between these results and the fact that a hepatic toxicity of pivampicillin was observed only in dogs among these animals was pointed out and discussed.
18 citations
TL;DR: Electron microscopy showed that localization of NiO particles was restricted to the lungs and that each particle had been engulfed by the alveolar macrophages.
Abstract: A special exposure system was used for the inhalation of nickel oxide (NiO) aerosol by Wistar male rats. The median aerodynamic diameter and the geometric standard deviation were 1.2 μm and 2.2, respectively. A histopathological study of the rats was performed immediately, and at intervals of 12 and 20 mo after a 1-mo expsoure to NiO. Electron microscopy showed that localization of NiO particles was restricted to the lungs and that each particle had been engulfed by the alveolar macrophages. Type II pneumocytes and nonciliated bronchiolar epithelial cells (Clara cells), as well as numerous tubular myelin (surfactant) in the alveoli were prominent. In rats dissected after 12 mo, clusters of NiO particles were still present within the terminal bronchioli, alveolar walls, and lysosomes of the alveolar macrophages. Pools of tubular myelin were observed in the peribron-chial lymphatics. The Clara cells, which project into the lumen of bronchioli, showed active secretion and were filled with smooth en-doplasmic reticulum (SER) in the apical cytoplasm. In the experimental group sacrificed after 20 mo, one rat had papillary adenocarcinoma and two rats showed adenomatosis in the peripheral portion of the lung, but none in the upper respiratory tract.
18 citations
TL;DR: It is suggested that there are no major differences in structural type or early postnatal development of chondroitin sulfate-type proteoglycans in the IPM between rds and normal mice and that photoreceptors may be critically involved in the maintenance of these matrix components.
18 citations
TL;DR: Although the present study shows that IL1B and IL1R1 expression occurs in all reproductive modes, the differential expression patterns noted between ovuliparity and ovipity and viviparity may reflect the different roles of IL1 in the various reproductive modes.
Abstract: In previous reports, we have shown that interleukin 1 (IL1), a cytokine associated with implantation in mice, is also expressed in reproductive tissues of viviparous squamate reptiles and cartilaginous fishes. In the present study, we investigated the expression of IL1B and its functional membrane receptor type I (IL1R1) in amphibians, a class of vertebrates that is characterized by different reproductive modes, including internal and external fertilization. In particular, we investigated the oviductal tissues of the aplacental viviparous Salamandra lanzai, the oviparous Triturus carnifex, and the ovuliparous Bufo bufo. In immunohistochemistry with anti-human IL1B and IL1R1 polyclonal antibodies we found that in S. lanzai, most cells in the uterine mucosa were immunoreactive for IL1B and IL1R1. In T. carnifex, IL1B and IL1R1 were present in ciliated luminal cells, and there was evidence of IL1B in glandular cells. In B. bufo, the expression of IL1B and IL1R1 was limited to the apical cytoplasm of the ciliated oviductal cells. Western blot analysis showed that a putative mature form of IL1B, similar to that seen in mammals, was present in the oviductal tissues of S. lanzai, whereas different forms, which probably correspond to an inactive pro-IL1B protein, were found in T. carnifex and B. bufo. A band that corresponded to the predicted 80-kDa human IL1R1 was found in S. lanzai and T. carnifex. Although the present study shows that IL1B and IL1R1 expression occurs in all reproductive modes, the differential expression patterns noted between ovuliparity and oviparity and viviparity may reflect the different roles of IL1 in the various reproductive modes.
18 citations
TL;DR: Observations show that an intense lipid absorptive process takes place in N. coriiceps digestive system, due to the great extension of the intestine involved and due toThe great lipid accumulation found in the epithelial compartment.
Abstract: Absorption of lipids by the enterocytes of Notothenia coriiceps, an omnivorous Antarctic and subAntarctic fish, was studied by light and electron microscopy. The lipids are absorbed by the anterior and middle intestine segments. They appear as fat droplets that measure from 0.5 to 7 μm of diameter and which accumulate in the apical cytoplasm within the first 24 h and seem to be the main fat storage form in the enterocytes. Fat is also observed as lipid particles with 60–300 nm inside the rough endoplasmic reticulum and cytoplasmic smooth vesicles. The epithelial intercellular space and the mucosal inner lamina contain lipid particles, which probably are the fat transport form. Our observations show that an intense lipid absorptive process takes place in N. coriiceps digestive system, due to the great extension of the intestine involved and due to the great lipid accumulation found in the epithelial compartment.
18 citations