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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: In normal, benign and malignant (with the exception of mucoid carcinoma) breast tissue the presence of DCG would appear to be related to hormonal changes and represent prelactational differentiation rather than providing evidence of neuroendocrine differentiation.
Abstract: In this study breast tissue from 114 patients has been examined ultrastructurally for dense core granules (DCG). The tissue included examples of normal 'resting', pregnant and lactating breast plus various benign and malignant lesions. DCG were observed in low numbers in the apical cytoplasm in a proportion of the examples of 'resting' and pregnant breast tissue but were absent in the lactating patients. The incidence appeared to relate to hormonal changes. They were present in 50 per cent of the benign lesions examined. DCG were also observed in a high proportion of the ductal, lobular and tubular carcinomas examined and were associated with luminal differentiation. In the mucoid carcinomas over half the tumours possessed some DCG with large numbers of DCG present within certain of the malignant cells in two cases. It is possible that the granules could be related to mucin secretion. Therefore, in normal, benign and malignant (with the exception of mucoid carcinoma) breast tissue the presence of DCG would appear to be related to hormonal changes and represent prelactational differentiation rather than providing evidence of neuroendocrine differentiation. We emphasize the need for a comprehensive knowledge of the normal morphological variations within a tissue before attempting to interpret its tumours.

24 citations

Journal ArticleDOI
TL;DR: Cloned and expressed FgSAP-2 and produced the antibody against this recombinant protein indicated that SAP-2 is a unique protein that is expressed only in late juvenile and adult F. gigantica, and it could be considered for immunodiagnostic and as a vaccine candidate for fasciolosis.
Abstract: Fasciola gigantica saposin-like protein-2 (FgSAP-2) belongs to a family of lipid-interacting proteins that are involved in the cytolysis of target cells. In this study, we have cloned and expressed FgSAP-2 and produced the antibody against this recombinant protein. Rabbit antiserum against rFgSAP-2 reacted with a similar native protein in the whole body extracts of the 4-week-old juvenile and adult stage, as well as a protein in their excretion–secretion, but not in the tegument. In situ hybridization and immunofluorescence detection revealed the presence of SAP-2 mRNA transcripts and proteins in the cecal epithelial cells of 4-week-old juvenile and adult parasites, but not in the metacercariae and newly excysted juveniles. Moreover, SAP-2 is present only in the cecal epithelial cells lining the distal part of the digestive tract, but not in the tegumental-type epithelium lining the proximal part of the digestive tract. The rFgSAP-2 reacted with antisera from rabbits infected with F. gigantica metacercariae collected at 5 weeks, but not at 2 weeks after infection. Anti-rFgSAP-2 did not exhibit any cross-reactivity with the other parasites' antigens, including Opisthorchis viverrini, Eurytrema pancreaticum, Cotylophoron cotylophorum, Fischoederius cobboldi, Gigantocotyle explanatum, Paramphistomum cervi, Setaria labiato-papillosa, and Haemonchus placei. This finding indicated that SAP-2 is a unique protein that is expressed only in late juvenile and adult F. gigantica, and it could be considered for immunodiagnostic and as a vaccine candidate for fasciolosis.

23 citations

Journal Article
TL;DR: The presence in the Clara cells of a secretory Mr 13,000 protein that binds methylsulfonyl-PCBs with high affinity gives further support to the contention that the protein is an important factor in determining the in vivo disposition of these compounds.
Abstract: Enriched cell populations from rat lung were isolated by use of elutriation. An in vitro ligand binding assay as well as a Western immunoblot assay were used to determine the levels of a binding protein for certain polychlorinated biphenyls (PCBs) in cytosolic preparations from these cell populations. The cell population enriched in Clara cells (30% Clara cells) contained by far the largest amount of the PCB-binding protein, 759 +/- 81 pmol/mg of cytosolic protein as judged by an in vitro ligand binding assay. Western immunoblot analysis of cytosolic preparations from the enriched cell preparations, using antibodies to the PCB-binding protein, showed levels of immunoreactive material in these fractions that corresponded to the level of the PCB-binding protein as determined by the in vitro ligand binding assay. By use of the peroxidase-antiperoxidase method of immunoperoxidase staining, antibodies to the PCB-binding protein were found to stain the Clara cells in sections of paraffin-embedded rat lungs. Intense immunoperoxidase staining of the material lining the airway epithelium was also observed. The protein was predominantly localized to the secretory granules in the apical cytoplasm of the Clara cells as determined using antibodies to the protein, protein A-gold, and electron microscopy. Previous studies have shown a selective in vivo accumulation of methylsulfonyl-PCBs in Clara cells of rodent lung and the present investigation, demonstrating the presence in the Clara cells of a secretory Mr 13,000 protein that binds methylsulfonyl-PCBs with high affinity, gives further support to the contention that the protein is an important factor in determining the in vivo disposition of these compounds.

23 citations

Journal ArticleDOI
TL;DR: It was concluded that PCR examination of faeces and serology probably provide more specific results than gross examinations at slaughter, and that a monoclonal antibody-based examination of ileum mucosa should be the accepted screening method for this infection.

23 citations

Journal ArticleDOI
TL;DR: This study is the first to describe co-localization of zinc vesicles with the specific zinc transporter ZnT4 in airway epithelium and loss of ZNT4 protein in inflamed airways, suggesting that nasal brushings may allow monitoring of airway Zn transporter expression.
Abstract: The apical cytoplasm of airway epithelium (AE) contains abundant labile zinc (Zn) ions that are involved in the protection of AE from oxidants and inhaled noxious substances. A major question is how dietary Zn traffics to this compartment. In rat airways, in vivo selenite autometallographic (Se-AMG)-electron microscopy revealed labile Zn-selenium nanocrystals in structures resembling secretory vesicles in the apical cytoplasm. This observation was consistent with the starry-sky Zinquin fluorescence staining of labile Zn ions confined to the same region. The vesicular Zn transporter ZnT4 was likewise prominent in both the apical and basal parts of the epithelium both in rodent and human AE, although the apical pools were more obvious. Expression of ZnT4 mRNA was unaffected by changes in the extracellular Zn concentration. However, levels increased 3-fold during growth of cells in air liquid interface cultures and decreased sharply in the presence of retinoic acid. When comparing nasal versus bronchial human AE cells, there were significant positive correlations between levels of ZnT4 from the same subject, suggesting that nasal brushings may allow monitoring of airway Zn transporter expression. Finally, there were marked losses of both basally-located ZnT4 protein and labile Zn in the bronchial epithelium of mice with allergic airway inflammation. This study is the first to describe co-localization of zinc vesicles with the specific zinc transporter ZnT4 in airway epithelium and loss of ZnT4 protein in inflamed airways. Direct evidence that ZnT4 regulates Zn levels in the epithelium still needs to be provided. We speculate that ZnT4 is an important regulator of zinc ion accumulation in secretory apical vesicles and that the loss of labile Zn and ZnT4 in airway inflammation contributes to AE vulnerability in diseases such as asthma.

23 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202112
20205
20195
20188
20175
201615