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Biomedical subjects

S Scarpa

Publications and source records attributed to S Scarpa.

At least 55 records · Page 3Linked to original sources
PubMed1993

Karyotype modifications in human malignant melanoma cell cultures after treatment with azelaic acid.

Azelaic acid (AzAc) is a C9 dicarboxylic acid which has recently been shown to have some therapeutic applications in skin diseases of different aetiologies. In order to study the in vitro activity of AzAc five human malignant melanoma primary cell cultures were treated for up to 60 days with 10 mM C9 2Na; the growth characteristics were defined by growth curve and the cytogenetics by Giemsa standard technique and GTG banding technique. Our data demonstrated an inhibition in replication of all five melanomas and the disappearance of the clones with chromosomal markers in four out of five melanomas after AzAc treatment.

Cell Division↗
PubMed1993

Platelet-derived growth factor effects on purified testicular peritubular myoid cells: binding, cytosolic Ca2+ increase, mitogenic activity, and extracellular matrix production enhancement.

The response of purified rat testicular peritubular myoid cells (PMC) to platelet-derived growth factor (PDGF) was studied. Freshly isolated PMC were devoid of measurable amounts of PDGF-binding sites. However, after 1 day in culture in serum-free conditions, specific high affinity receptors were detected. The estimated binding sites per cell revealed that PMC express more receptors for PDGF-BB, followed by PDGF-AB and PDGF-AA. PDGF treatment of cultured PMC increased the cytosolic Ca2+ concentration, showing a rank order of potencies with PDGF-BB > PDGF-AB > PDGF-AA. PMC proliferation, as measured by direct cell counting, was also stimulated by all three PDGF isoforms, with the same order of potencies observed for the increase in intracellular Ca2+. This effect was inhibited by antibodies to PDGF. Moreover, PDGF treatment increased the release of type IV collagen and fibronectin, and induced the release of type V collagen and laminin. These results demonstrate that testicular PMC are induced to express functionally active PDGF receptors in response to cell culturing. These data suggest that PMC may be a target for PDGF and that PDGF-mediated effects in vivo are dependent on factors regulating the expression of the receptors. The role that PDGF may play in normal and pathological testicular processes is discussed.

Animals↗
PubMed1992

Modulation of laminin synthesis in human neuroblastoma cells during retinoic acid induced differentiation.

A comparable pattern of morphological neuronal differentiation was induced in the human neuroblastoma cell line SMS-KCNR by treatment with either retinoic acid (RA) or exogenous laminin (LM). LM expression and synthesis by SMS-KCNR was increased upon RA treatment which involved the cell bound, rather than the secreted protein. These data suggest an involvement of LM in the neuroblastoma differentiation process manifested both as an ability of LM to induce a morphological neuronal differentiation and as a selective control on LM metabolism during RA induced neuronal differentiation.

Cell Differentiation↗
PubMed1992

Neuromodulatory loop mediated by nerve growth factor and interleukin 6 in thymic stromal cell cultures.

Neural crest cell derivatives have been suggested to be involved in thymus development. We established nonlymphoid thymic stromal cell cultures capable of supporting T-cell differentiation. In these nonlymphoid cell cultures, we identified cells with phenotypic and biochemical markers specific for neuronal cells. Neurofilament mRNA and 68- and 160-kDa neurofilament proteins, as well as 74-kDa synapsin I isoform, were expressed in many of the cultured cells. For example, neurofilament immunoreactivity was detected in 20-30% of the cells. To see whether thymic neuronal-like cells were involved in a neural differentiation pathway, we investigated the effect of nerve growth factor (NGF) and interleukin 6 (IL-6), two known neurotrophic factors. The expression of the above-described neural markers was enhanced by NGF and IL-6, which we report to be produced in an autocrine way by thymic stromal cell cultures. Finally, we found that IL-6 gene expression in these cell cultures was enhanced by NGF. Evidence is thus offered of a neuromodulatory loop within the thymic stromal cell population supported by local production of NGF and IL-6 and involving neural cell elements. Interestingly, IL-6, which is known to be implicated in thymocyte differentiation, also displays a neuromodulatory activity on thymic stromal cells, suggesting a multivalent role for this cytokine within the thymus.

Animals↗
PubMed1992

Rat Leydig cells bind platelet-derived growth factor through specific receptors and produce platelet-derived growth factor-like molecules.

The platelet-derived growth factor (PDGF) is a major mitogen for cells of mesenchymal origin. Because Leydig cells arise from mesenchymal precursors, we tested the hypothesis that these cells might be a target for PDGF. We also investigated a possible production of a PDGF-like substance by Leydig cells in culture and the distribution of PDGF-like material in the rat testis using immunohistochemistry. PDGF was found to bind specifically to high affinity receptors on the surface of purified adult rat Leydig cells. Conditioned medium from cultured Leydig cells competed with 125I-labeled PDGF for binding to the Leydig cells. The secretion of PDGF receptor-competing activity was stimulated in a dose-dependent manner by the trophic hormone hCG. Immunohistochemical studies revealed specific staining for PDGF in the Leydig cells of adult rat testis. Taken together these observations suggest that PDGF may play a role in the local control mechanisms of testicular function.

Animals↗
PubMed1992

[The effect of aging on the replication activity of human gingival fibroblasts in vitro].

Human gingival fibroblast primary cultures were obtained from healthy donors of different ages (20/50/65 years). The identity and homogeneity of the histotype were determined by immunofluorescence of cytoskeletal intermediate filaments (vimentin versus cytokeratin). Cell growth characteristics and doubling times, determined by growth curves, were compared in the same culture, during aging process induced in vitro, and also in cultures from donors of different ages. A progressive decrease of proliferation was found during both physiologic aging in vivo and induced aging in vitro.

Adult↗
PubMed1992

[The modification of the extracellular matrix synthesized in vitro by human gingival fibroblasts in relation to aging].

Human gingival fibroblast primary cultures were obtained from healthy donors of different ages (20/50/65 years). The synthesis of extracellular matrix was analyzed and the relative protein production was compared either in different cultures at the same passage or in the same culture at following passages. In the first passages of the 3 cultures the protein patterns resulted similar in quantity and quality. However, a quantitative modification in protein synthesis was evident in each culture during the aging process induced in vitro, with a progressive decrease in global protein production, parallel to the increase of the number of culture passages.

Adult↗
PubMed1991

[Extracellular matrix in gingival fibroblasts].

Primary cultures of human gingival fibroblasts from patients of different age have been established. Histotype characterization has been confirmed by ultrastructural morphology and by the positivity of intermediate filament vimentin. Extracellular matrix expression has been analyzed by immunocitochemistry. Our data demonstrate that the extracellular matrix of human gingival fibroblasts is composed of type IV collagen, other than fibronectin and type I-III collagens.

Cells, Cultured↗
PubMed1991

Decrease of proliferation rate and induction of differentiation by a MYCN antisense DNA oligomer in a human neuroblastoma cell line.

The effects of an antisense oligodeoxynucleotide to codons 2-7 of the oncogene MYCN on the human neuroblastoma cell line LAN-5 were studied. Treated cells showed a decreased MYCN protein expression and synthesis by immunoperoxidase staining and immunoprecipitation. At the same time, the replication rate was inhibited, and the phenotype was modified toward a more differentiated type. Our data suggest the involvement of oncogene MYCN in both proliferative and differentiative processes.

Base Sequence↗
PubMed1990

Low doses of IL-4 injected perilymphatically in tumor-bearing mice inhibit the growth of poorly and apparently nonimmunogenic tumors and induce a tumor-specific immune memory.

The ability of rIL-4 to trigger host reactivity against both a chemically induced fibrosarcoma (CE-2) and a spontaneous adenocarcinoma (TS/A) of BALB/c mice was studied. Daily local s.c. administration around tumor draining lymph nodes of 10 injections of progressive amounts (0.00001 to 1000 pg/day) of rIL-4 induced appreciable inhibition of the growth of both tumors after a dose-response survival curve peaking at 0.1 pg/day. Inasmuch as rIL-4 has no direct antitumor activity, as shown by in vitro tests, host immune reactivity plays a fundamental role in this lymphokine activated tumor inhibition (LATI). LATI, in fact, is abolished when recipient mice are sublethally irradiated or treated with cyclosporin A, or when the reactivity of CD4+ lymphocytes is suppressed, whereas it is not affected by anti-asialo GM1 antibody. The morphologic data show that rIL-4 LATI rests on the recruitment of several cell reaction mechanisms, among which those that are nonspecific seem to predominate. rIL-4 LATI also leads to a state of long lasting and specific immune memory: the growth of a second contralateral tumor challenge is significantly impaired after LATI. This immune memory takes place after LATI of both the poorly immunogenic CE-2 fibrosarcoma and the TS/A adenocarcinoma, previously classed as nonimmunogenic on the basis of immunization-protection tests. In the latter case, adoptive transfer experiments show that Thy-1+ lymphocytes and, in particular, the CD4 cell-depleted T lymphocyte subpopulation, are responsible for the immune memory. Finally, the ability of rIL-4 to trigger LATI is greater than that of the most effective doses of rIL-2, rIL-1 beta, and IFN-gamma, whereas its association with rIL-1 beta induces a more effective immune memory.

Adenocarcinoma↗
PubMed1990

Human malignant melanoma. Significance of chromosomal abnormalities.

Although many reports on chromosome changes in human malignant melanoma (HMM) have been published, it is still impossible to define the significance of the different markers reported. In fact, we think that the difficulties in interpreting the chromosomal abnormalities could be due to poorly defined clinical conditions and a lack of correlation with cytological and histological analyses. To verify this hypothesis, we studied 10 cell lines obtained from 8 patients affected by cutaneous malignant melanoma that were well defined for their clinical, histologic, and cytogenetic aspects. No significant correlation was found among these parameters, and, hence, the cytogenetics findings cannot be used to determine a more detailed diagnosis or a more definite prognosis.

Chromosome Aberrations↗
PubMed1989

Rat natural killer cells synthesize fibronectin. Possible involvement in the cytotoxic function.

The ability of NK cells to synthesize and secrete fibronectin (FN), an extracellular matrix glycoprotein which plays a key role in many biologic processes including cellular adhesion, morphology, cytoskeletal organization, cell migration, and invasiveness, was studied. By using affinity-purified polyclonal antibodies directed against human cellular or plasma FN, the presence of FN was evidentiated on Percoll-purified rat large granular lymphocyte or on a large granular lymphocyte tumor cell line (CRC) by flow cytometry and immunoelectron microscopy. Its expression increased after NK cell activation by poly I:C administration. Biochemical analysis by immunoprecipitation and SDS-PAGE indicated that FN was associated to cell surface and secreted in the supernatant in a molecular form similar to that of FN from L929 fibroblasts. In an attempt to understand the role of FN in the NK cell function, we found that an antibody against human plasma FN and its F(ab')2 fragment inhibited NK cytotoxicity against YAC-1 target at the effector cell level. Inhibition occurred at the postbinding level, because F(ab')2 anti-FN inhibited induction of phosphatidylinositol hydrolysis by YAC-1 target cells, whereas binding to target cells was not affected. The possible role of FN in the NK cytotoxic function is suggested.

Animals↗
PubMed1989

Establishment and characterization of a human neuroblastoma cell line.

A continuous human cell line RN-GA was established from a stage-III primary neuroblastoma prior to therapy. Light and electron microscopic analysis of the biopsy showed morphological features typical of neuroectodermal origin. Relative cellular DNA content and N-myc oncogene copy number were also analyzed in the biopsy tissue: the tumor cells presented a near-diploid genome with N-myc amplification. The derived tumor cell line expressed distinctive ultrastructural, cytogenetic and immunological markers of neuroblastoma. Moreover, cells from the culture could be serially transplanted into splenectomized-irradiated nude mice, where they formed a progressively growing solid tumor. Surprisingly, the cells in culture did not show any N-myc amplification, while they retained a near-diploid DNA content. We propose that several techniques (electron microscopy, oncogene analysis, flow cytometry, cytogenetics, tissue culture, cell antigen immunodetection) should be used to establish a firm diagnosis and a correct clinical grading of this tumor. The establishment of this continuous cell line should be valuable as an experimental in vitro system for further studies of neuroblastoma biology and morphology.

Adrenal Gland Neoplasms↗
PubMed1989

Laminin synthesis by NK cells and modulation of its expression by TPA (12-O-tetradecanoylphorbol-13-acetate).

Natural killer (NK) cells have been suggested to play a major role in resistance against metastatic spread of tumors. This study was aimed at understanding whether laminin (LM), a component of the extracellular matrix involved in the mechanism of tumor invasion and cell interaction, is expressed by NK cells. The results indicate that NK cells can synthesize and display on the cell surface LM and that TPA can modulate its expression. Our findings suggest that the presence of LM on NK cells could be relevant in the control of tumor invasion by NK cells.

Animals↗
PubMed1989

Zinc uptake in human seminal spermatozoa: characterization and effects on cell membranes.

Human ejaculated spermatozoa take up zinc in a time- and concentration-dependent manner. The kinetics of 65Zn2+ uptake is suggestive of an at least partly carrier-mediated transport. The lack of effect of the respiratory chain inhibitor antimycin A could mean that mitochondrial ATP is not required as an energy source for the uptake. The failure of nonpermeant SH reagent mersalyl to modify zinc uptake indicates that functional membrane sulfhydryl groups are not involved in the process. A dose-dependent inhibition of 65Zn2+ uptake was induced by the "anticalmodulin" drug trifluoperazine, suggesting that the calcium-binding protein calmodulin could have a role in zinc transport. In in vitro experiments this cation brought about a powerful effect in protecting the spermatozoa from being damaged by hypo-osmosis.

Antimycin A↗
PubMed1989

[Diagnostic use of the cell culture technique in a case of postoperative saccate lymphorrhea].

The Authors demonstrated the presence of tumour cells by an in vitro culture of the cells from the pellet of a postoperative saccate effusion, when no tumor cells were evident by the cytologic examination of the effusion. The ultrastructural features and the immunocytochemical characteristics of the cell line were analyzed and these data confirmed its malignant nature. It allowed a firm diagnosis, a correct therapy and prognosis.

Breast Neoplasms↗
PubMed1989

[Study of pollen of allergologic significance in the urban atmosphere of Parma in the years 1983-1984].

From 1983 to 1984 pollen air samples from Parma's urban atmosphere were collected weekly by means of a Burkard recording volumetric spore trap. Data regarding a few of the meteorologic variables were also collected at the same time: temperature, insulation, water precipitation, humidity and wind speed. Some of the more allergenic pollens and their concentration/m3 air were determined from the collected samples: Graminea, Urticaceae, Fagaceae, Salicaceae and Betulaceae. Looking at the results from the period of study, it can be seen that Graminea and Urticaceae were the most represented in comparison with the other families. Graminea was most represented in May 1983, in June 1984 and during the first week of September 1984; Urticaceae in September 1983, May 1984 and September 1984. These pollen concentrations were also compared to the meteorologic data.

Italy↗