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Biomedical subjects

C Arcuri

Publications and source records attributed to C Arcuri.

17 recordsLinked to original sources
PubMed1997

A time-dependent increase in glial fibrillary acidic protein expression and glutamine synthetase activity in long-term subculture of the GL15 glioma cell line.

1. Astrocytes are the most numerous cellular elements in the central nervous tissue, where they play a critical role in physiological and pathological events. The biological signals regulating astrocyte growth and differentiation are relevant for both physiology and pathology, but they are still little understood. 2. Using a poorly differentiated glioma cell line, GL15, we investigated whether, in long-term subculture, this could upregulate the expression of glial fibrillary acidic protein (GFAP), as described in some rodent astrocyte cell lines. Under the same culture conditions, we investigated glutamine synthetase (GS) activity, growth-associated protein (GAP)-43 expression, and expression of several neutrotrophic factors. 3. A dramatic increase in GFAP expression was evidenced by Western blotting during progressive in vitro growth of GL15 cells. GS specific activity was also upregulated in long-term culture. The time spent in vitro by GL15 cells did not affect GAP-43 and neutrophic factor BDNF and NT3 expression as revealed by RT-PCR analysis. 4. Our results suggest that, in GL15, GFAP and GS genes may have common or integrated regulatory mechanisms elicited at the cell confluency which could be relevant for both astrocyte physiology and astrocyte pathology. These mechanisms are not involved in GAP-43 and neutrophic factor BDNF and NT3 expression.

Astrocytes↗
PubMed1997

A comparative light microscopic study of human midpalatal suture and periodontal ligament.

In order to provide information on the morphological features of both human midpalatal suture and periodontal ligament, bioptic samples were obtained from patients whose age was between 10 and 30 years. The samples were embedded in epoxy resin, sectioned, stained with toluidine blue and observed by light microscopy. The periodontal ligament and the midpalatal suture appeared very similar with regard to the histological characteristics of the connective tissue but differed in the nature of the bone tissue associated to it. The alveolar bone lining the periodontal ligament was a bundle bone whereas the bone lining the connective tissue of the sutures was both lamellar and bundle bone. The absence of osteoblasts, osteoclasts or undifferentiated cells in the sutures under examination suggests that they are subjected to a slow bone turnover during their life cycle. On the contrary, the presence of mesenchymal cells in the periodontal ligament supports the notion that these cells are precursors of osteogenic cells involved in the high rate of bone remodelling that characterizes the alveolar bundle bone. The present results are discussed taking into account physiologic and therapeutic aspects of the two structures under examination.

Humans↗
PubMed1996

Large T antigen coding sequences of two DNA tumor viruses, BK and SV40, and nonrandom chromosome changes in two glioblastoma cell lines.

The T antigen (TAg) coding sequences of two DNA tumor viruses, BKV and SV40, were detected by Polymerase Chain Reaction (PCR) amplification followed by Southern-blot hybridization in two human glioblastoma multiforme derived cell lines. RT-PCR analysis indicated that these two TAg coding sequences were expressed in both tumor cell lines carrying the viral early region DNAs. Moreover, analytical polyacrylamide gel electrophoresis (PAGE) and DNA sequence analyses showed that the amplified PCR products are indistinguishable from the TAg coding sequences of BKV and SV40 wildtype strains. Cytogenetic study performed in the two cell lines showed unbalanced changes, mainly gains of chromosomes 3p, 5, 6, 7, and 19 and losses of chromosomes 3, 3q, 16, 9p22-->pter, 18, and 20. Excess of chromosomes 6 and 7 are common to the two cell lines. The putative role of the TAg of the two DNA tumor viruses in transformation and karyotype changes is discussed.

Antigens, Viral, Tumor↗
PubMed1995

PKA and PKC activation induces opposite glial fibrillary acidic protein (GFAP) expression and morphology changes in a glioblastoma multiform cell line of clonal origin.

Possible differentiation mechanisms were investigated in a glioblastoma multiform cell line (GL15) presenting an undifferentiated phenotype with weak glial fibrillary acidic protein (GFAP) and strong vimentin (VIM) expression. Serum-free conditions induced time-dependent increases of GFAP-mRNA and GFAP protein levels, associated with a process-bearing astrocytic morphology. Activation of protein kinase C (PKC) by tumor promoter phorbol 12-myrystate 13-acetate (PMA) induced a rapid morphological differentiation and a decrease in GFAP mRNA, whereas the GFAP level remained unchanged. Such parameters were shown to characterize a physiological differentiation stage in astroglial cultures. Treatment of process-bearing GL15 cells with dibutyryl cyclic AMP (dbcAMP), a protein kinase A (PKA) activator, induced a time-dependent decrease in the GFAP mRNA and GFAP protein levels and reverted morphological changes induced by serum-free conditions. Neither PMA nor dbcAMP influenced the VIM mRNA expression. In GL15 cells, PKC and PKA activation have opposite effects. Understanding the role of these kinases in malignant transformation and in the in vitro differentiation process is of both basic and clinical interest.

Blotting, Northern↗
PubMed1995

Glutamine synthetase gene expression in a glioblastoma cell-line of clonal origin: regulation by dexamethasone and dibutyryl cyclic AMP.

We investigated the expression of glutamine synthetase (GS), an enzyme involved in astroglial metabolism and marker of astroglial functional maturity, in a glioblastoma cell-line (GL-15) of clonal origin. In spite of their phenotypic immaturity, evidenced in a mosaic fashion by a poor glial fibrillary acidic protein (GFAP) expression, the level of GS-mRNA is high in GL15 cells and the considerable amount of GS biological activity can be further induced and stabilized by glucocorticoids. A correlation between the induction by dexamethasone of the GS-mRNA level and the GS biological activity suggests a transcriptional regulation of GS expression by the aforesaid hormone. Under this hormonal action, changes in cell morphology occur and they are correlated with an overexpression of the GFAP, a marker of astroglial differentiation. On the contrary, dibutyryl cyclic AMP (dbc AMP) down-regulates the GS-mRNA expression and decreases GS activity. These results suggest that GL-15 cells have a common glucocorticoid dependent mechanism able to induce GS and GFAP as well as morphological changes. However in these cells AMPc responsive elements are involved in the negative modulation of the GS expression, contrary to what occurs in normal astroglial cells.

Astrocytes↗
PubMed1993

Glial fibrillary acidic protein and its encoding mRNA exhibit mosaic expression in a glioblastoma multiform cell line of clonal origin.

The expression of two astroglial differentiation markers, vimentin and glial fibrillary acidic protein, was investigated in a previously established human glioma cell line of clonal origin (GL15). Vimentin immunolabelling was homogeneously expressed in all cells. Glial fibrillary acidic protein and its encoding message, investigated by immunocytochemistry and in situ hybridization, showed a mosaic-like expression. Only 30% of the cell population expressed glial fibrillary acidic protein and its mRNA. Western and Northern blots performed for both markers confirmed the presence of both proteins and messages, and their level was correlated with the observed antigenic and molecular probe labelling. The overall antigenic pattern suggests that GL-15 cells do not belong to the O-2A progenitor cell lineage and may arise from a clonal expansion of astrocyte precursors.

Biomarkers↗
PubMed1990

[Impacted maxillary third molars. Accidental dislocation].

During surgical removal of impacted maxillary third molars, many complications may occur. Their accidental displacements in the maxillary sinus or in the infratemporal fossa are not too rare in the common general dentistry. Presenting this case, the Authors want to demonstrate that, when each one of this kind of teeth are well studied before their treatment, many complications can be avoided and, the sooner the dentist is able to solve them when they occur, the better the post-operative course will be.

Adult↗
PubMedDate not supplied

A light microscopic investigation of the human midpalatal suture.

Biopsy samples of the human midpalatal suture, obtained from patients (age range: 10 and 30 yrs), were embedded in resin, cut with ultramicrotome and analyzed at light microscopy. The sutural connective tissue was made up of fibroblasts, collagen fibers, capillaries and nerve fibers. The sutural bone was made up of lamellar and bundle bone which alternated along both sides of the sutural connective tissue. No osteoblasts or osteoclasts were found, no signs of synostosis were ever detected. Our findings suggest that the lamellar bone replaces bundle bone when the suture is no longer involved in the growth of the palatal bones. The absence of bone remodelling shows that the sutures, at the time of sampling, were in a resting stage. Tissue architecture and cell types, so similar in samples from patients of such different ages, lead us to suppose that the sutures under examination are subject in time to very slow bone turnover.

Adolescent↗