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Biomedical subjects

N Maggiano

Publications and source records attributed to N Maggiano.

At least 73 records · Page 4Linked to original sources
PubMed1992

Growth-inhibitory effect of quercetin and presence of type-II estrogen-binding sites in human colon-cancer cell lines and primary colorectal tumors.

We studied the effect of quercetin (Q) on the proliferation of HT-29, WiDr, COLO 201, and LS-174T human colon cancer cell lines. Q, between 10 nM and 10 microM, exerted a dose-dependent, reversible inhibition of cell proliferation. Cell-cycle analysis revealed that the growth-inhibitory effect of Q was due to a blocking action in the G0/G1 phase. Using a whole-cell assay with 17 beta-[3H]-estradiol as tracer, we demonstrated that all these cell lines contain type-II estrogen-binding sites (type-II EBS). By using Q and other chemically related flavonols (3,7-4'-trimethoxyquercetin, 3,7,3',4'-tetramethoxyquercetin, kaempferol, morin, and rutin), we observed that the affinities of these compounds for type-II EBS are correlated with their growth-inhibitory potential. Furthermore, the Q sensitivity of the colon cancer cell lines was correlated with the number of type-II EBS/cell. Then Q could regulate colon cancer cell growth through a binding interaction with type-II EBS. This mechanism could also be active in vivo as we have observed that cytosolic type-II EBS are present in primary colorectal cancers and that Q is effective in inhibiting the in vitro bromodeoxyuridine incorporated by neoplastic cells in these cancers.

Adenocarcinoma↗
PubMed1992

Expression of intermediate filaments and actins in human dental pulp and embryonic dental papilla.

The localization of different cytoskeletal proteins (keratin, vimentin, desmin, actin, and alpha-smooth muscle actin) was examined by immunohistochemistry in normal human adult dental pulp and compared with dental papilla of tooth germs. Keratin and actin were localized in enamel organ. Vimentin and actin were observed in the dental papilla and in the adult dental pulp. Desmin and alpha-smooth muscle actin were present only in the vessel walls. These data are discussed paying particular attention to the origin and the peculiar functional characters of the dental papilla and pulp.

Actins↗
PubMed1992

Antibody binding to endothelial and epithelial antigens triggers pig-to-rabbit xenograft rejection and its absence results in atypical complement deposition.

In pig-to-rabbit kidney xenograft (PRKX), endothelial antigen determinants (EAD) are immediately recognized by IgG and IgA, while IgM does not react with them. The purpose of this study was to investigate the different roles of IgG, IgA, IgM, and complement in the hyperacute rejection of a PRKX model. Nine isolated Landrace pig kidneys were each perfused with 10 ml normal New Zealand rabbit serum. Perfusates (serum A) were collected after discarding the first 0.5 ml. Serum A and rabbit complement were then incubated for 30 min with frozen sections of normal pig kidney. After washing with buffer solution all the specimens were treated for immunohistochemistry. Three frozen sections of normal Landrace pig kidney and three samples of normal New Zealand rabbit serum were used as controls. Immunohistochemical analysis of the nine perfused kidneys demonstrated IgG, IgA and C3 deposition on the peritubular and glomerular vascular endothelium. No IgM reactivity was shown. In the frozen sections exposed to serum A, immunofluorescence showed minimal IgG, IgA and C3 reactivity while IgM deposition was clearly evident on the tubular epithelium. Immunofluorescence of frozen sections exposed to rabbit complement, done by fluorescein-labeled goat anti-rabbit C3 antibodies were positive only in the glomerular endothelium. The same rabbit complement was active in antibody dependent cytotoxicity on human T cells. Our results indicated that in the PRKX model, IgG and IgA acted as preformed antibodies recognizing endothelial EAD. IgM did not bind to any endothelial molecules, but recognized antigens located on the brush border of the tubular epithelium. Furthermore, in this model, absence of antigen-antibody complexes resulted in atypical complement deposition.

Animals↗
PubMed1992

Comparative immunohistochemical analysis between jaw myxoma and mesenchymal cells of tooth germ.

The histogenesis of jaw myxoma is still debated. According to some authors it arises from the primitive mesenchymal components of developing teeth. In this study, we have studied the expression of S-100 protein and vimentin in dental follicle, dental papilla and periodontal ligament cells using monoclonal and polyclonal antibodies. Myxoma of the jaw expresses vimentin and S-100 protein. On the contrary, as compared to jaw myxoma, the normal developmental structures were immunonegative for S-100 protein but stained for vimentin. These results could indicate a difference in the derivation other than tooth mesenchyma.

Biomarkers, Tumor↗
PubMed1991

Detection of mRNA and hnRNA using a digoxigenin labelled cDNA probe by in situ hybridization on frozen tissue sections.

A full-length cDNA clone encoding the constant region of T cell receptor beta chain was labelled by random priming DNA with digoxigenin-dUTP. The probe was used to estimate the relative amount of the receptor beta chain mRNA by in situ hybridization on frozen sections from human thymus and lymph nodes. The hybridization was visualized in blue using an anti-digoxigenin antibody conjugated with alkaline phosphatase and a subsequent enzyme-catalysed colour reaction. The distributions of the signal in tissue sections were as expected. Moreover, labelled cells showed hybrids both in the cytoplasm and in the nucleus, and strongly and weakly stained cells were clearly distinguishable. The results indicate that this method of in situ hybridization should be useful in the detection of specific mRNA in frozen sections.

Child, Preschool↗
PubMed1990

Intrathymic deficient expansion of T cell precursors in Down syndrome.

To correlate the intrinsic cellular immunodeficiency, which is a major cause of increased susceptibility to polytopic infections in Down syndrome (DS) patients, with the histologic abnormalities observed in the thymus of these patients, we have studied thymus fragments and thymocyte cell suspensions from 15 non-institutionalized DS subjects. Comparing to the control age-matched samples, a reduced thymic cortex and a distinct depletion of CD1-positive (+) cells was observed by immuno-histologic examination. The phenotypic analysis of unselected thymocytes showed a significant reduction of CD3+, CD1+, CD4+, and CD8+ cells. When the total thymocyte population was separated into 10 fractions, using a continuous Percoll density gradient, a difference in cell distribution was observed. DS thymuses are almost devoid of high-density thymocytes (fractions 6-9) while more than 75% of the cells were recovered in the lightest 3 fractions (Frs). In addition, these thymuses were characterized by a marked depletion of CD1+ cells and by a conspicuous reduction of CD3+ cells normally present in the high-density Frs. On the other hand, the lightest 3 Frs of DS subjects were enriched in low-density CD1+ cells. Although enriched in these cells, normally characterized by a high mitotic activity, Fr1 DS thymocytes showed a reduced spontaneous proliferative capacity. When the expression of T cell receptor alpha- and beta-subunits was studied, the percentages of cells stained with anti-alpha and anti-beta antisera were found to be reduced in DS unfractionated thymocytes. The reduced number of high-density CD1+ thymocytes associated with a reduced spontaneous proliferative activity of low-density CD1+ thymocytes suggests that in DS thymuses there is a deficient expansion of immature T cells, resulting in a reduction of the various thymocyte subpopulations, including the thymocyte pool which differentiates into functionally mature T cells expressing the alpha-beta T cell receptor.

Child, Preschool↗
PubMed1990

Morphological and immunohistochemical study of Down syndrome thymus.

The incidence and severity of various histologic changes were studied in the thymuses from 35 Down syndrome (DS) patients. Variable histologic alterations up to fibrotic involution of the gland were found. In addition, immunohistochemical investigation showed a reduction or absence of interdigitating reticulum cells roughly correlated with the severity of morphologic changes. The complex architectural and cellular thymic alterations, concerning both cortical and medullary microenvironment, could be correlated with the imbalances of immunity in DS patients.

Child, Preschool↗
PubMed1990

Neuropeptide-immunoreactive cells in human thymus.

The outer cortex of the human thymus contains a one- to two-cell-thick layer that is immunoreactive with antisera against beta-endorphin, (Leu)- and (Met)-enkephalin, bombesin, and substance P. The epithelial nature of these immunostained cells is revealed by immunoelectron microscopic studies showing the presence of desmosomal junctions. The presence of peptide-containing cells in the outer cortex, where the most immature and recently immigrated thymocytes are found, emphasizes the role of neuropeptides in regulating the microenvironment for T cell development.

Cell Differentiation↗
PubMed1990

Cells immunoreactive for neuropeptide in human thymomas.

The presence of opioid peptides, bombesin, and substance P was investigated by immunohistochemistry in tissue sections from six human thymomas. The number of immunoreactive cells seemed to vary from one case to another. Ultrastructural investigation, showing the presence of desmosomes in labelled cells, allowed these cells to be classified as epithelial lineage cells. The occurrence of cells containing neuropeptide in thymomas suggest that peptide molecules could have modulated the behaviour of this tumour, given the reported influence of these molecules on immune functions and their growth promoting activity on several cell types, including mesenchymal and epithelial cells.

Aged↗
PubMed1990

Interleukin-2 receptor expression in human mast cells and basophils.

Surgical human thymus, upper respiratory tract, lung and small and large bowel specimens were analyzed for the presence of interleukin 2 receptor (IL2-R)-positive cells. Histochemical (toluidine) and immunologic (anti-IL2-R monoclonal antibody) staining procedures revealed a distinct anti-IL2-R positivity in most of metachromatically staining cells. These positive cells were observed not only in tissues showing strong inflammatory reaction and mast cell hyperplasia, as in Crohn's disease, but also in those not histologically affected by pathologic conditions. This finding suggested that human mast cells, like T blast cells, express the p55 chain of IL2-R on their surface. To see whether IL2-R was being actively synthesized, a cell preparation rich in peripheral blood basophils (PBB), which are cells closely related to mast cells, was obtained. Ultrastructural analysis of PBB after indirect immunogold procedure revealed that the vast majority expressed the IL2-R. Moreover, the presence of intracellular reaction products in the cytoplasm of most membrane-positive PBB was indicative of active antigen synthesis. Furthermore, Northern blot analysis evidenced specific IL2-R mRNA in PBB, while its expression was augmented several times when PBB were cultured in the presence of stimulated T cell supernatant.

Animals↗
PubMed1989

Biologic and molecular characterization of producer and nonproducer clones from HUT-78 cells infected with a patient HIV isolate.

HUT-78 cells were infected with a reverse transcriptase (RT)-positive supernatant of a culture of peripheral blood lymphocytes (PBL) from an AIDS patient and then cloned. Of these clones, two have been isolated and characterized. Clone D10 is persistently and productively infected with an HIV variant. The clone F12, in spite of the presence of an integrated full-length HIV provirus, does not release virus particles in the medium. D10 and F12 clones substantially differ in terms of protein pattern; that is, D10 is super-imposable to infected HUT-78 cells, whereas F12 exhibits a decreased uncleaved p55 gag precursor and the presence of uncleaved gp160 and of a unique p19, although they do not show qualitative or quantitative differences in viral RNA synthesis. Restriction patterns of F12 proviral DNA do not show major genomic deletions. These results indicate that F12 clone cells carry an HIV genome with minor mutations that probably affect the correct production of viral proteins at a posttranscriptional level. In addition, the F12 clone is resistant to high-multiplicity superinfection with HIV-1 or HIV-2.

Cells, Cultured↗
PubMed1989

Immunopathology of nasal polyps: an immunohistochemical approach.

We studied the mast cells and the T-lymphocyte subpopulations of four patients' nasal polyps using immunohistochemical procedures. The data showed that MC displayed IL2-receptor and that they were very often closely related to CD4+ and MHC class II-positive T-lymphocytes. CD8-positive T-cells represented only 10% to 15% of the whole lymphoid population and were not localized near mast cells. These findings suggest a possible role of cell-mediated immune reactions in the pathogenesis of nasal polyps.

Adult↗
PubMed1989

The expression of functional IL-2 receptor on activated macrophages depends on the stimulus applied.

Human peripheral blood monocytes (Mo) synthesize prostaglandin E2 (PGE2) when activated with lipopolysaccharide (LPS). This production is strongly enhanced by the addition of supernatant from phytohaemagglutinin (PHA)-activated T cells. To evaluate the factor(s) responsible for this enhancement we studied the effect of several cytokines on the PGE2 metabolism. Recombinant interleukin-1 (IL-1) or recombinant IL-2 strongly enhanced PGE2 synthesis in LPS-stimulated Mo cultures, whereas recombinant interferon-gamma (IFN-gamma) partially inhibited its production. To see whether the effect of IL-2 on Mo was due to the presence of IL-2 receptor (IL-2R) on the cell surface, flow cytometric analysis and electron microscopy were used to investigate IL-2R expression in unstimulated and stimulated Mo. Stimulated, but not resting, Mo displayed the p55 IL-2R chain on their cellular surface and associated with the polyribosomes of the rough endoplasmic reticulum in the cytoplasm. This finding strongly suggested that the p55 chain of the IL-2R was synthesized by activated Mo. To confirm this result, 125I-labelled IL-2 was bound under high- and low-affinity conditions and cross-linked to Mo cultured in the presence of LPS, IFN-gamma or IL-1. The cross-linked 125I-IL-2/IL-2R complexes were analysed by SDS-PAGE. Mo cultured with LPS, IFN-gamma and IL-1 expressed the p55 protein detected by low-affinity cross-linking, whereas only LPS-stimulated Mo displayed a barely detectable band with an apparent MW of 70,000 under high-affinity binding conditions. In addition, stimulated Mo were found capable of producing the soluble form of IL-2R. Finally, LPS-activated Mo only responded to the addition of IL-2 by an increase in PGE2 production, suggesting that the function of IL-2R on activated Mo is linked to the stimulus applied.

Biological Factors↗