Electron microscopic observations and X-ray microanalysis of a multinucleated giant cell

Bay, Boon‐Huat; Chan, Yee-Gek; Yick, T. Y.; Leong, Hoo-Kwong

doi:10.1093/oxfordjournals.jmicro.a023604

Cited by 8 publications

(6 citation statements)

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“…Immunoelectron Microscopy-The rats were perfused in 0.5% glutaraldehyde and 4% paraformaldehyde before processing for electron microscopy (EM) as described previously (32). Briefly, post-osmicated samples were dehydrated in an ascending series of ethanol and embedded in araldite.…”

Section: Methodsmentioning

confidence: 99%

Localization of the Cyclic ADP-ribose-dependent Calcium Signaling Pathway in Hepatocyte Nucleus

Khoo¹,

Han²,

Park³

et al. 2000

Journal of Biological Chemistry

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CD38 is a type II transmembrane glycoprotein found on both hematopoietic and non-hematopoietic cells. It is known for its involvement in the metabolism of cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate, two nucleotides with calcium mobilizing activity independent of inositol trisphosphate. It is generally believed that CD38 is an integral protein with ectoenzymatic activities found mainly on the plasma membrane. Here we show that enzymatically active CD38 is present intracellularly on the nuclear envelope of rat hepatocytes. CD38 isolated from rat liver nuclei possessed both ADP-ribosyl cyclase and NADase activity. Immunofluorescence studies on rat liver cryosections and isolated nuclei localized CD38 to the nuclear envelope of hepatocytes. Subcellular localization via immunoelectron microscopy showed that CD38 is located on the inner nuclear envelope. The isolated nuclei sequestered calcium in an ATP-dependent manner. cADPR elicited a rapid calcium release from the loaded nuclei, which was independent of inositol trisphosphate and was inhibited by 8-amino-cADPR, a specific antagonist of cADPR, and ryanodine. However, nicotinic acid adenine dinucleotide phosphate failed to elicit any calcium release from the nuclear calcium stores. The nuclear localization of CD38 shown in this study suggests a novel role of CD38 in intracellular calcium signaling for non-hematopoietic cells.CD38 is a 42-45-kDa type II transmembrane glycoprotein (1) found in various mammalian tissues and cell types and is capable of converting NAD ϩ into cyclic ADP-ribose (cADPR) 1 (2). This ability is due to the ADP-ribosyl cyclase activity found on the extracellular carboxyl domain of the enzyme. The product, cADPR, possesses calcium mobilizing activity independent of inositol 1,4,5-trisphosphate (IP 3 ) (3). Instead, cADPR seems to regulate calcium mobilization through the calcium-inducedcalcium release mechanism (4, 5). In addition to cyclizing NAD ϩ to cADPR, CD38 is also able to use NADP ϩ as a substrate and catalyze the exchange of its nicotinamide group with nicotinic acid to produce NAADP (5), another potent calciummobilizing metabolite.CD38 is generally believed to be an important surface immunoregulatory molecule; its myriad of possible functions include the induction of B and T cell proliferation (6), regulation of the humoral immune response (7), apoptosis (8), tyrosine phosphorylation of various proteins (9), activation of certain kinases (10), and cytokine release (11). CD38 also displays adhesion properties and might possibly mediate a selectin-type adhesion between different blood populations and human vascular endothelial cells via its putative ligand, CD31 (12). In addition to its immuno-functions, CD38 has been shown to play an important role in insulin secretion via the cADPR-dependent calcium signaling pathway (13). Indeed, results suggest the appearance of autoantibodies to CD38 in patients may contribute to the development of noninsulin-dependent diabetes (14).The calcium stores mobilized by c...

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Section: Methodsmentioning

confidence: 99%

Localization of the Cyclic ADP-ribose-dependent Calcium Signaling Pathway in Hepatocyte Nucleus

Khoo¹,

Han²,

Park³

et al. 2000

Journal of Biological Chemistry

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“…Tissue from a confirmed undifferentiated NPC (by light microscopy) was fixed in 3% glutaraldehyde and 2% paraformaldehyde before osmication in 2% osmium tetroxide as previously described (Bay et al, 1998). Post-osmicated samples were dehydrated in an ascending series of ethanol and embedded in epoxy resin.…”

Section: Transmission Electron Microscopy and Immunoelectron Microscopymentioning

confidence: 99%

Correlation of metallothionein expression with apoptosis in nasopharyngeal carcinoma

et al. 2000

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The expression of metallothionein (MT), an intracellular ubiquitous low molecular weight protein thiol with antioxidant properties, was studied in nasopharyngeal cancer (NPC) and correlated with the apoptotic index. Immunohistochemical staining of randomly selected, formalin-fixed and paraffin-embedded normal and malignant nasopharyngeal tissues were analysed for the expression of MT using the commercially available E9 antibody directed against MT I and MT II isoforms. The corresponding apoptosis labelling indices were evaluated by the TUNEL method. Localization of MT at the ultrastructural level was studied by immunogold labelling. All the tumour sections (17 specimens) showed MT-immunopositivity. A direct correlation between the percentage of MT-positive cells and the staining intensity was noted (P< 0.001; Pearson's r = 0.95). There was absence of cytoplasmic staining and only nuclear staining (with localization in the nucleoplasm) was demonstrated in the tumour cells. In normal epithelium of the nasopharynx, the basal layer was stained. An inverse relationship was observed between the level of MT expression and the apoptotic index in the NPC tissues (P = 0.0059; Pearson's r = –0.6380). The results suggest that overexpression of MT in NPC may protect the tumour cells from entering into the apoptotic process and thereby contribute to tumour expansion. Preferential localization of MT in the nuclei of NPC cells may possibly enhance radioresistance since radiotherapy is known to eradicate tumour cells by free radical-induced apoptosis. © 2000 Cancer Research Campaign

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“…Several studies have reported that inflammatory multinucleated giant cells (3) and macrophages, especially those in the lymph nodes, phagocytose iron nanoparticles (4 -7), but nothing is known about the fate of extracellular particles.…”

mentioning

confidence: 99%

Distribution of iron oxide nanoparticles in rat lymph nodes studied using electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI)

Bréchot

Sich

Réty

et al. 2000

J. Magn. Reson. Imaging

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Electron microscopic observations and X-ray microanalysis of a multinucleated giant cell

Cited by 8 publications

References 0 publications

Localization of the Cyclic ADP-ribose-dependent Calcium Signaling Pathway in Hepatocyte Nucleus

Localization of the Cyclic ADP-ribose-dependent Calcium Signaling Pathway in Hepatocyte Nucleus

Correlation of metallothionein expression with apoptosis in nasopharyngeal carcinoma

Distribution of iron oxide nanoparticles in rat lymph nodes studied using electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI)

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