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Biomedical subjects

L Fiore

Publications and source records attributed to L Fiore.

At least 37 records · Page 2Linked to original sources
PubMed1998

Reduced expression of interleukin 6 in undifferentiated thyroid carcinoma: in vitro and in vivo studies.

Cytokines appear to play an important role in the development and progression of epithelial tumors. Cultured normal human thyroid follicular cells constitutively release high levels of interleukin-6 (IL-6) and IL-8, together with low to moderate levels of transforming growth factor-alpha (TGF-alpha) and TGF-beta. IL-6 appears to play multiple functions in thyroid physiology and disease. Because certain data indicate an inverse relationship between IL-6 production and epithelial tumor aggressiveness, we used both tissue culture methods and histochemical techniques to search for possible alterations of cytokine expression in thyroid carcinomas. As compared to cultures from normal tissue and well-differentiated carcinoma, production of IL-6 was strongly down-regulated in cultures derived from undifferentiated carcinoma. In contrast, levels of IL-8, TGF-alpha, and TGF-beta produced by neoplastic TFC were similar to those produced by normal cells. Actually, production of TGF-alpha was slightly enhanced in cultures from well-differentiated carcinoma. Immunoassay results were confirmed by reverse transcriptase-PCR analysis. Immunohistochemistry of human thyroid carcinomas (n = 99) and normal thyroid tissue (n = 85) showed that immunoreactive IL-6 was strongly diminished in undifferentiated forms (n = 34) and slightly reduced in well-differentiated carcinoma (n = 65). In agreement with the in vitro results, TGF-alpha expression was significantly increased in neoplastic thyrocytes, as compared to their normal counterpart. The results indicate that, as in the mammary and salivary glands, down-regulation of IL-6 expression may represent a marker of undifferentiated thyroid carcinoma.

Carcinoma↗
PubMed1997

Down-regulation of the nm23.h1 gene inhibits cell proliferation.

nm23 gene expression is strictly related to the state of cell growth. The level of its expression parallels the fraction of thymidine-incorporating cells (S-phase cells) in neoplastic mammary tissues and in the synchronously cycling fraction of MCF 1OA cells. nm23.h1 reaches a peak of expression in the S-phase, and is present at very low level during the GO/G1 phase. Two strategies are used to demonstrate the direct involvement of the nm23.h1 gene in the process of cell proliferation. The first consists of transient inhibition of nm23.h1 expression by using anti-sense oligonucleotide treatment; weak inhibitory effect on cell proliferation is observed. The second strategy involves the stable inhibition of nm23.h1 expression by transfection of MCF1OA cells with a plasmid vector expressing the human nm23.h1 anti-sense mRNA. The anti-sense-transfected cells show consistently slower proliferative activity than the control.

Breast↗
PubMed1997

Apoptosis and proliferation in thyroid carcinoma: correlation with bcl-2 and p53 protein expression.

The aim of this study was to determine the apoptotic cell death in 92 thyroid carcinomas of different histotypes (42 papillary, PTC; 12 poorly differentiated, PDC: 21 undifferentiated, UC; and 17 medullary, MC) by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin nick end labelling (TUNEL). Apoptotic index (Al, evaluated as a percentage of TUNEL-positive cells of neoplastic cells) was calculated in each tumour. The AI was very low in all subtypes of thyroid carcinoma, ranging from a median value of 0.2 in PTC to 1.4 in UC. The proliferative activity was determined by immunohistochemistry using monoclonal antibody, MIB-1. The percentage of proliferating cells was significantly different among the histotypes, increasing with tumour aggressiveness (from the mean value of 3.1 for PTC to 5.6 for PDC and 51.8 for UC). In addition, the ratio between proliferative activity and apoptosis was significantly higher in UC than in the other histotypes. The expression of bcl-2 and p53 protein (important in the modulation of cell death) was correlated (bcl-2, inverse correlation, r2 = 0.1, P = 0.04; p53, direct correlation, r2 = 0.11, P = 0.02) with apoptotic index in PTC.

Antigens, Nuclear↗
PubMed1997

Unimmunized Gypsy populations and implications for the eradication of poliomyelitis in Europe.

The certification of poliomyelitis eradication in Europe will eventually require that countries demonstrate there is a minimal risk of wild poliovirus reintroduction and sustained transmission through unimmunized subpopulations such as ethnic minorities. A serologic survey among a Gypsy community in Italy found that despite only 26% documented immunization coverage, serum neutralizing antibodies to poliovirus types 1, 2, and 3 were detected in 81%, 94%, and 63% of the 86 persons studied. While the high level of immunity found in this community may have been due to secondary spread of vaccine virus, the possibility of unrecognized circulation of wild polioviruses cannot be excluded. Targeted immunization of such groups may be the most efficient means of eliminating the risk of importation-associated outbreaks.

Adolescent↗
PubMed1997

Poliovirus Sabin type 1 neutralization epitopes recognized by immunoglobulin A monoclonal antibodies.

Immunity to poliomyelitis is largely dependent on humoral neutralizing antibodies, both after natural (wild virus or vaccine) infection and after inactivated poliovirus vaccine inoculation. Although the production of local secretory immunoglobulin A (IgA) antibody in the gut mucosa may play a major role in protection, most of information about the antigenic determinants involved in neutralization of polioviruses derives from studies conducted with humoral monoclonal antibodies (MAbs) generated from parenterally immunized mice. To investigate the specificity of the mucosal immune response to the virus, we have produced a library of IgA MAbs directed at Sabin type 1 poliovirus by oral immunization of mice with live virus in combination with cholera toxin. The epitopes recognized by 13 neutralizing MAbs were characterized by generating neutralization-escape virus mutants. Cross-neutralization analysis of viral mutants with MAbs allowed these epitopes to be divided into four groups of reactivity. To determine the epitope specificity of MAbs, virus variants were sequenced and the mutations responsible for resistance to the antibodies were located. Eight neutralizing MAbs were found to be directed at neutralization site N-AgIII in capsid protein VP3; four more MAbs recognized site N-AgII in VP1 or VP2. One IgA MAb selected a virus variant which presented a unique mutation at amino acid 138 in VP2, not previously described. This site appears to be partially related with site N-AgII and is located in a loop region facing the VP2 N-Ag-II loop around residue 164. Only 2 of 13 MAbs proved able to neutralize the wild-type Mahoney strain of poliovirus. The IgA antibodies studied were found to be produced in the dimeric form needed for recognition by the polyimmunoglobulin receptor mediating secretory antibody transport at the mucosal level.

Animals↗
PubMed1997

Cytokine production by a new undifferentiated human thyroid carcinoma cell line, FB-1.

A human anaplastic thyroid cancer cell line FB-1, derived from a 68-yr-old woman who underwent surgery for anaplastic thyroid cancer, has been established. The spindlelike cells have been proliferating stably for more than 2 yr. Karyotype analysis shows many abnormalities and many marker chromosomes have been observed. Heterotransplant of FB-1 cells into severe combined immunodeficient mice has resulted in rapidly growing tumors classified as anaplastic carcinomas, although 50% have shown areas with a trabecular pattern. FB-1 cells failed to express messenger RNA for thyroglobulin; TSH-receptor; thyroperoxidase, and placental angiogenic growth factor. Conversely, PAX8 and thyroid transcription factor 1, whose expression is thyroid specific, was kept in an FB-1 cell line at a level comparable with that observed in normal thyroid tissue. In addition, the present cell line expressed high levels of messenger RNA for high-mobility group proteins (Y) and -C. The in vitro study revealed that FB-1 cells are able to produce high levels of interleukin (IL)-8 and medium amount of IL-6, whereas no release of IL-1-alpha, IL-1-beta, and IL-4 was observed. No modulation of cell proliferation and DNA synthesis in FB-1 cells has been observed after the addition of exogenous IL-6.

Aged↗
PubMed1996

Application of non-linear filters based on the median filter to experimental and simulated multiunit neural recordings.

Two non-linear, high-pass filters based on the median filter are proposed and tested as substitutes for linear filtering in applications involving multiunit neural recordings. The first, the median-based high-pass (MH) filter, operates by subtracting the output from the input of the median filter; it is aimed at preserving the shape of the impulses. The second, the negative median-based high-pass (NMH) filter, sets at zero the positive values in the output of the MH filter; it is aimed at transforming the impulses into monophasic waves placed on a flat baseline. When applied to experimental recordings and to a template action potential, the two median-based filters clearly outperformed two corresponding procedures based on a linear filter (moving-average filter). They did not produce appreciable distortions of the impulses, whereas their two counterparts induced or enlarged lateral lobes, as is the rule for linear high-pass filters. The recording display was much improved and impulse identification was made easier. When the two filters were applied to simulated recordings and the mean output was estimated by averaging and cross-correlation, a certain degree of performance deterioration was assessed in conditions of sustained activity and/or noise, with a resulting growing similarity to the mean output of the two corresponding, moving-average-based filters.

Animals↗
PubMed1996

Production and characterization of murine IgA monoclonal antibodies to the surface antigens of rhesus rotavirus.

Rotavirus is the single most important cause of severe diarrhea in humans and is diffuse in most animal species worldwide, and an understanding of the antigenic properties of the virus is essential to the design of rational vaccine strategies. To better understand the localization of viral epitopes involved in antibody-mediated neutralization of virus infectivity, we have orally immunized mice with live rhesus rotavirus (RRV) and generated a panel of hybridoma cell clones secreting IgA class monoclonal antibodies. A total of 12 neutralizing IgA MAbs to VP4 and VP7 proteins were studied for their epitope specificity and topographical relationships by hemagglutination-inhibition assays, neutralization assays, and competitive-binding assays with previously mapped MAbs. In addition, neutralization-escape virus mutants were selected and gene segments for each variant were cloned and sequenced. Two IgA MAbs were found to be directed to the antigenic region A of the VP7 protein at amino acid 94, and 10 MAbs were directed at the VP8 trypsin cleavage fragment of VP4. Five of the VP4-specific MAbs identified the same neutralization epitope on the RRV VP8 protein, not previously associated with RRV neutralization. All neutralization-escape variants selected by this antibody group contained mutations at amino acids 132- 135 of VP4. One IgA MAb selected for a mutation at amino acid 190 of VP4, and the corresponding viral mutant failed to agglutinate erythrocytes. This MAb mapped to an epitope recognized by 2 additional IgA MAbs. These results suggest that oral immunization of mice with RRV elicits an IgA immune response which is predominantly directed toward antigenic determinants on the VP8 portion of VP4. As a consequence, the route of immunization may alter immunodominant neutralization responses elicited to rotavirus.

Animals↗
PubMed1996

Expression of and response to interleukin 6 (IL6) in human mammary tumors.

Multifunctional cytokines play important and only partially defined roles in mammary tumor development and progression. Normal human mammary epithelia] cells (MECs) constitutively produce interleukin (IL) 6, IL8, and a nonsecreted form of tumor necrosis factor. MEC transformation by different oncogenes is frequently associated with alterations of cytokine/growth factor production and responsiveness. This seems particularly true in the case of IL6. Histochemical studies showed that expression of immunoreactive IL6, as compared to normal tissue and to in situ lesions, is significantly reduced in invasive ductal carcinoma. Conversely, the expression of IL6 in invasive lobular carcinoma was enhanced. Expression of TGF-beta1 in mammary neoplasia was in general less intense than that seen in the normal mammary gland. In vitro studies partially supported the in vivo findings: expression of IL6 and TGF-beta1 was significantly down-regulated in cultures derived from both ductal carcinoma and peritumoral tissue. Similarly, responsiveness to IL6 and TGF-beta1 was significantly reduced in neoplastic MECs. The data suggest that alterations of cytokine pathways are present not only in mammary neoplasia, but also in pathologically unaffected breast tissues.

Breast↗
PubMed1996

Comparison of capillary blood versus venous blood samples in the assessment of immunity to measles.

Seroepidemiological investigations are essential for assessing the efficacy of measles vaccination programmes. However, when large-scale sampling is needed, a major difficulty is the problem of taking venous blood, especially in children. An alternative method is the collection of capillary blood samples spotted on filter papers. The eluted extract from these 'blood' spots can be used instead of serum samples for measles laboratory diagnosis or investigations. Measles antibody detection is readily carried out by ELISA on serum samples. The same technique can be used on eluates from capillary blood spots. Measles antibody titres determined on matched serum and blood spot samples from 27 children were compared. A strong correlation was found between the results obtained with the two methods of blood sampling.

Antibodies, Viral↗
PubMed1996

Defective interleukin six expression and responsiveness in human mammary cells transformed by an adeno 5/SV40 hybrid virus.

Mammary epithelial cells (MECs) were isolated and cultured from mammary glands of healthy women undergoing reduction mammoplasty. Normal MECs were infected with the transforming hybrid virus adeno-5/SV40. Two transformed epithelial cell lines, M1 and M2, were obtained, characterised phenotypically and studied for the production of and the response to cytokines and growth regulators. In both cell lines, expression of the SV40 large T antigen was associated with loss of interleukin 6 (IL-6) production and responsiveness as well as with down-regulation of IL-8 and transforming growth factor (TGF)-alpha production. Both M1 and M2 cell lines were capable of forming colonies in semisolid media, but upon injection into severe combined immunodeficient (SCID) mice only M2 cells were tumorigenic. DNA synthesis in M1 cells was partially inhibited by serum or TNF-alpha and weakly stimulated by hydrocortisone (HC) and IL-8. In contrast, M2 cells were totally unresponsive to a variety of growth regulators. Both lines overexpressed the p53 protein at levels about 20-fold higher than those observed in primary MEC cultures, but no mutations of the p53 gene could be detected. The date confirm the view that the expression in human mammary cells of different oncogenes - including the SV40 T antigen - is frequently associated with alterations of cytokine production and responsiveness.

Adenocarcinoma↗
PubMed1996

Serotonin is involved in the ACTH-induced reversal of hemorrhagic shock in anesthetized rats.

In a rat model of volume-controlled hemorrhagic shock (mean arterial pressure = 20-24 mm Hg) causing the death of all saline-treated animals within 30 min, the i.v. bolus injection of ACTH-(1-24) (160 micrograms/kg) produced an almost complete and sustained reversal of the shock condition, with recovery of arterial blood pressure, pulse pressure and respiratory rate, and with 100% survival at the end of the experiment (2 h). The serotonin-depleting agent p-chlorophenylalanine (316 mg/kg i.p., administered 66-70 h before hemorrhage) almost completely prevented the effect of ACTH. The 5-HT1/5-HT2 receptor antagonist, methysergide, prevented the effect of ACTH completely when injected i.v. (5 mg/kg), but only in part when injected into a brain ventricle (i.c.v.) (15 micrograms/rat); the 5-HT2 antagonist, ketanserin, prevented the effect of ACTH completely when injected i.c.v. (1.5 micrograms/rat), but only in part when injected i.v. (0.5 mg/kg); the 5-HT3 antagonist, MDL 72222, largely prevented the effect of ACTH when injected i.c.v. (10 micrograms/rat), but had no influence at all when injected i.v. (3 mg/kg); finally, the 5-HT4 antagonist, GR 125487, had no effect when injected i.v. (5 micrograms/kg) or when injected i.c.v. (30 ng/rat). Overall, these data indicate that both CNS and peripheral serotonin play an important role in the complex mechanism of the ACTH-induced hemorrhagic shock reversal.

Animals↗
PubMed1995

NM23 gene expression correlates with cell growth rate and S-phase.

Two human NM23 genes have been identified: NM23.H1 and NM23.H2 coding for the A and B subunit of a nucleoside diphosphate kinase (NDPK), respectively. NM23.H1 gene has been proposed as a suppressor of metastatic ability in tumor cells, NM23.H2 is identical to the c-myc transcription factor, PuF. The NM23 coding sequence is strongly preserved through different species. Indirect evidence of various types has been accumulated and seems to support an implication of NM23 in cell proliferation. This report shows that the NM23 gene expression is strictly related to the growth state of the cells. Two different in vitro systems (human peripheral blood lymphocytes and human breast epithelial cell line MCF-10A) and one in vivo (human primary infiltrating ductal breast carcinomas) system have been investigated. The mRNA is present in PHA-stimulated peripheral blood lymphocytes, whereas it is nearly undetectable in their resting counterparts. The level of the NM23 gene expression parallels the fraction of cells incorporating thymidine (S-phase) in neoplastic mammary tissues. In synchronously cycling MCF-10A cells NM23.H1 mRNA reaches a maximum abundance in the S-phase and is absent or only present at very low levels during G0/G1 phase, whereas NM23.H2 is present in growth-arrested cells but is upregulated following serum growth stimulation.

Breast↗
PubMed1995

Immunogenicity, antigenicity, and protection efficacy of baculovirus expressed VP4 trypsin cleavage products, VP5(1)* and VP8* from rhesus rotavirus.

Rhesus rotavirus (RRV) VP4 trypsin cleavage product VP5(1)*, a truncated form of VP5*, was expressed in baculovirus and found by immunoprecipitation to be antigenically similar to VP5* on the virion. Immunization of mice with VP5(1)* elicited neutralizing antibody that was found to be cross-reactive with viruses representing P genotypes 1, 3, 4, 6, 7, and 8. Baculovirus expressed trypsin cleavage products, VP8* (amino acids 1-246) and VP5(1)* (amino acids 247-474), were tested for their ability to elicit a protective response in a murine model of passive protection. These results were compared to those obtained with baculovirus expressed RRV VP4. Dams immunized with baculovirus expressed RRV VP4 gave birth to pups protected from RRV virus challenge. Neither VP5(1)* nor VP8* was as effective at generating protective immunity as full length VP4. However, antibody to VP5(1)* was more effective than antibody to VP8* at mediating protection even though the neutralizing antibody titers as measured by hemagglutination inhibition and focus reduction neutralization were similar.

Animals↗