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Biomedical subjects

A Faggioni

Publications and source records attributed to A Faggioni.

At least 73 records · Page 4Linked to original sources
PubMed1989

Localization of Epstein-Barr virus envelope glycoproteins on the inner nuclear membrane of virus-producing cells.

Epstein-Barr virus-producing cells were used as a model to analyze, with a fracture-immunolabel technique, the distribution, behavior on fracture, and extent of glycosylation of viral transmembrane glycoproteins at the inner nuclear membrane. Surface and fracture immunolabeling with two monoclonal antibodies directed against the carbohydrate or polypeptide portions of the major viral envelope glycoproteins gp350/220 showed the following. (i) The glycoproteins present on the inner and outer nuclear membranes were labeled only with the monoclonal antibody directed against the polypeptide chain, whereas over the surface of virus-producing cells and on mature virions the labeling was dense and uniformly distributed with both monoclonal antibodies. (ii) The glycoproteins were nonuniformly distributed only over the inner nuclear membranes; at the sites of viral budding, the glycoproteins showed a preferential partition with the protoplasmic face. Since fully glycosylated glycoproteins were not present on the nuclear membranes, our observations support the proposed model of herpesvirus maturation. The peculiar distribution and partition on fracture of the envelope glycoproteins on the inner nuclear membrane are similar to those of Sindbis virus envelope glycoproteins on the plasma membrane of infected cells. Therefore, our results suggest that inner nuclear membranes may behave like plasma membranes during viral assembly.

Antigens, Viral↗
PubMed1989

Changes of immunological patterns of human cancer cells treated in vitro with a triazene compound.

Previous experimental evidence indicates that immunogenicity of mouse tumor cells can be increased by treatment with dacarbazine and other triazene compounds. The present studies have been conducted on the human cell lines H125 (lung cancer), 1246 (melanoma), X3 (EBV-immortalized B cells) subjected to in vitro treatment with 4 (3-methyl-1-triazeno) benzoic acid potassium salt (MTBA). Untreated or drug-treated sublines were tested for susceptibility to allogeneic NK effector cells, either non-stimulated or pretreated with beta-Interferon. In the case of X3 cell line and its MTBA-treated subline the expression of the EBV-associated antigens and the capability of eliciting autologous cytotoxic T lymphocytes (CTL) were also investigated. The results suggest that a modification of membrane antigenic pattern could be induced by MTBA treatment in terms of changes of cell susceptibility to cell-mediated lysis, expression of EBV-related antigens and capability to elicit autologous CTL.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1989

Interaction of HIV and EBV at lymphoid tissue level: immunohistochemistry and in situ hybridization.

The presence of Epstein-Barr virus antigens and genome was studied in lymph nodes from HIV + patients affected by PGL. Cryostat sections from 50 lymph nodes of HIV + patients were immunostained with EBV-VCA (viral capsid antigen), EBV-EA (early antigen) and p24 HIV major core protein monoclonal antibodies. In situ hybridization was performed using a biotin conjugated EBV DNA probe; the reaction product was demonstrated by immunohistochemical method. As positive controls, EBV producer B95-8 and HIV infected H9 cell lines were used. The majority of patients had circulating EBV antibodies mainly directed against the viral capsid antigen and only in few cases against early antigens. Positivity for HIV p24 protein was detected in 43 out of 50 lymph nodes within the germinal centers with a reticular pattern. Only 2 out of 50 lymph nodes presented very few positive cells for EBV antigens and none expressed detectable EBV genome. Our results suggest that EBV cellular expression does not correlate with serum positivity; furthermore the absence of EBV antigens and genome at tissue level might indicate that EBV is not directly involved in the pathogenesis of PGL.

AIDS-Related Complex↗
PubMed1989

Percutaneous fibercholangioscopies.

This is a report on our experience in 309 percutaneous fiberendoscopies of the biliary tract done in 106 patients of the 115 scheduled for the procedure. We describe the relevant approaches, techniques, complications and results. In particular, percutaneous transhepatic cholangioscopies (PTCS) were accomplished on transhepatic percutaneous drainages located radiologically in 35 patients: in 13 for differential diagnosis to distinguish between malignant and benign stenoses (diagnostic accuracy in 92% of the biopsies), in 22 cases with therapeutic intent, including 14 lithotomies for extrahepatic biliary tract calculosis, combined in 4 cases with a simple dilatation of the papilla and a percutaneous "descending" papillotomy; in 7 patients a dilatation of the biliary tract (BT) or of the stenosis of a biliodigestive anastomosis was accomplished (malignant in 4 patients, benign in 3 patients). In 38 patients postoperative percutaneous transhepatic cholangioscopies were performed along surgically located transparietohepatic drains, both to assess the biliodigestive anastomosis healing process carried out by two different techniques (30 patients), and to complete the biliary tract drainage as part of the primary and secondary endoscopic surgical treatment of massive intrahepatic lithiasis. In two further patients affected by such pathology, PTCS was done in combination with fibercholangioscopy performed via a transjejunal approach using a Völker drain on a Y-shaped loop. Nine of these patients were treated successfully and one patient later underwent a left hepatectomy, since attempts to drain that area had remained unsuccessful. The transjejunal approach was carried out in 3 patients as a diagnostic measure: in two cases to check the lithotomy, and in one case to check a cholangiojejunal anastomosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Biliary Tract Diseases↗
PubMed1988

Nonrandom distribution of epidermal growth factor receptors on the plasma membrane of human A431 cells.

The localization of epidermal growth factor (EGF) receptors over the plasma membranes of human epidermoid carcinoma A431 cells was analyzed at the electron microscopic level using surface replica techniques and conventional thin sections, in combination with immunocytochemistry. Immunolabeling was performed using two distinct monoclonal antibodies directed against the extracellular portion of the receptor, followed by protein A-colloidal gold conjugates. Unexpectedly, with the first monoclonal antibody used, the distribution of the receptors in both unfixed and glutaraldehyde-fixed cells was clearly regionalized, showing a preferential localization of the immunolabeling at the cell periphery as well as over the areas rich in microvilli and in coated and uncoated pits. A similar pattern of distribution was observed also with the other monoclonal antibody, but only when the cells were fixed with glutaraldehyde before immunolabeling. Treatment with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate modifies this distribution, inducing a more disperse pattern. Our observations suggest that a minor group of EGF receptors, which may represent the high-affinity receptors, presents a regional distribution, similar to that described for typical recycling receptors.

Carcinoma, Squamous Cell↗
PubMed1987

TPA induction of Epstein-Barr virus early antigens in Raji cells is blocked by selective protein kinase-C inhibitors.

We have shown that modulation of intracellular calcium in EBV latently infected cells could induce the expression of viral antigens, and suggested that a protein kinase-C (PKC) may play a major role in the EBV genome activation. We now report further investigations on the role of PKC using 2 selective enzymatic inhibitors [1-(5-Isoquinolinylsulfonyl)-2-methylpiperazine] (H-7) and Staurosporine. We show that these inhibitors can abrogate the inductive effect of TPA or the combination of TPA plus n-butyrate. The inhibitors have no effect on induction by calcium ionophores or by viral superinfection. In this context the effect of verapamil (a specific calcium channel blocker) and of several calmodulin antagonists was investigated. No inhibitory effect of these agents could be demonstrated on any of the induction systems examined. These observations strengthen the idea that in some instances cellular PKC plays a role in the expression of viral antigens; however, alternative regulatory mechanisms cannot be excluded.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1987

Mechanism of antitumoral activity of catechols in culture.

Cell lines Raji and K 562, lacking tyrosinase, and two melanotic human melanoma cell lines (IRE 1 and IRE 2), were exposed to concentrations from 5 X 10(-3) M to 10(-5) M of different phenols which are substrates of tyrosinase, i.e. l-dopa, dopamine, hydroquinone, terbutylcatechol, and of phenols which are not substrates of the tyrosinase, i.e. resorcinol, butylated hydroxyanisole and hydroquinone dimethyl ether. Cultures were carried out in the presence or in the absence of oxygen radical scavenger enzymes superoxide dismutase, catalase and peroxidase. The stability of each substance in culture medium was assayed by high performance liquid chromatography (HPLC). Results showed that: catechols which are substrates of tyrosinase decompose fully after 24 hr in medium; they are equally toxic for melanoma and non-melanoma cell lines; their toxicity increases when they are preincubated in medium for 24 hr and 48 hr before addition of cells; their toxicity is significantly reduced by addition of scavenger enzymes; on the contrary, phenols not substrates of tyrosinase are stable in medium and their toxicity is not reduced by scavenger enzymes. It is concluded that tyrosinase does not play a major role in catechol toxicity in vitro, which is probably due to some products of catechol decomposition, especially oxygen radicals, acting outside the cells.

Anisoles↗
PubMed1987

Nasopharyngeal carcinoma: the diagnostic value of the antibody-dependent, cellular cytotoxicity test and of EBV serology.

In the present study we report the results of the EBV-specific antibody response in 30 Italian NPC patients, 20 other head and neck tumor patients and 20 healthy controls. Histopathologically, the tumors were classified as squamous cell carcinoma (WHO 1), nonkeratinizing carcinoma (WHO 2) and undifferentiated carcinoma (WHO 3). Immunofluorescence tests were performed in order to evaluate the antibodies against VCA, EA and the EBV nuclear antigen (EBNA), and the antibody dependent cellular cytotoxicity test was used to detect the EBV specific antibodies against membrane antigens. IgG and IgA antibodies to EBV VCA and IgG antibodies to EA were significantly and consistently higher in the NPC patients than in other patients or controls. Moreover, only the WHO 2 and WHO 3 histological types of NPC resulted associated with EBV. ADCC titers ranging from 1:480 to 1:15360 have been determined; low ADCC titers were prevalent among the VCA-IgA positive donors, while VCA-IgA negative donors presented high ADCC titers. Our results look consistent with other previous results in low-risk and high-risk areas. In conclusion, EBV serology seems to be extremely useful for diagnostic purposes; however, in order to assess a prognostic value of the above markers, a greater number of patients followed for a longer period is needed.

Antibodies, Viral↗
PubMed1986

Calcium modulation activates Epstein-Barr virus genome in latently infected cells.

In many viral infections the host cell carries the viral genome without producing viral particles, a phenomenon known as viral latency. The cellular mechanisms by which viral latency is maintained or viral replication is induced are not known. The modulation of intracellular calcium concentrations by calcium ionophores induced Epstein-Barr viral antigens in lymphoblastoid cell lines that carry the virus. When calcium ionophores were used in conjunction with direct activators of protein kinase C (12-O-tetradecanoyl phorbol-13-acetate and a synthetic diacylglycerol), a greater induction of viral antigens was observed than with either agent alone. Activation of protein kinase C may be required for the expression of the viral genome.

Aminoquinolines↗
PubMed1986

Proliferating and quiescent cells exhibit different subcellular distribution of protein kinase C activity.

The activity of calcium, phospholipid-dependent protein kinase (PKc), which is thought to play an important role in cell proliferation, has been measured in the particulate and soluble fractions of cultured cells, under different proliferative conditions. Our results indicate that proliferating cells display higher PKc activity than quiescent cells. Furthermore, in both normal and transformed cells, PKc is preferentially associated with the particulate fraction when the cells are proliferating, while in mitotically quiescent cells the majority of the enzyme activity is found in the soluble fraction. These data suggest tha PKc activity and subcellular distribution undergo spontaneous changes according to the proliferative state of the cells.

Animals↗
PubMed1985

Epstein-Barr virus serology in nasopharyngeal carcinomas and other head and neck neoplasms in Italy.

This paper reports the results of the EBV-specific antibody response in 17 Italian nasopharyngeal carcinoma (NPC) patients, 15 other head and neck tumor patients and 15 normal controls. Nucleic acid hybridization has been performed on the biopsy tissue from 4 of the NPC patients, and EBV-DNA was present in two undifferentiated (WHO 3) tumors, and absent in two samples of the keratinizing (WHO 1) type. EBV serology appears to be specifically related to NPC, more evidently for VCA-IgA and EA-IgG antibodies, and useful as an aid in diagnosis of NPC. However, in order to assess a prognostic value of the above markers, a greater number of patients followed for a longer period of time (at least 5 years) is needed, and is currently being pursued.

Adult↗
PubMed1985

Herpesvirus saimiri-induced lymphoblastoid rabbit cell line: growth characteristics, virus persistence, and oncogenic properties.

A nonproducer lymphoblastoid cell line (7710) containing the herpesvirus saimiri (HVS) genome was established from the HVS-positive spleen of a male, inbred New Zealand White rabbit (III/J strain) which had developed a well-differentiated lymphoma after inoculation of HVS and 12-O-tetradecanoylphorbol-13-acetate (TPA). Antibodies to HVS early and late antigens were detected in the serum of rabbit 7710 by indirect immunofluorescence and immunoprecipitation. The cell line was of T-cell origin, did not produce HVS, and could not be superinfected with HVS. However, HVS early antigens could be induced in the cells with n-butyric acid and TPA or TPA alone. On the other hand, late antigens were never observed, and infectious virus could not be rescued by cocultivation of 7710 cell with OMK cells. The 7710 cells were T-cell growth factor dependent, even after many in vitro passages. The 7710 cell line contained multiple copies of a nonintegrated, covalently closed circular HVS genome. As is characteristic of some other HVS-transformed nonproducer lymphoid cell lines, a large segment of unique light (L) DNA was missing in the persistent circular viral DNA present in 7710 cells. This deletion spanned at least 42.5 kilobases, corresponding to the segment between 12.3 and 50.7 map units of full-length, infectious virion L-DNA. The 7710 cells failed to induce tumors in athymic nude mice, but inbred rabbits inoculated with as few as 100 of these cells developed fatal lymphomas. Chromosomal analysis showed that tumors were due to the growth of donor cells. Cells recovered from one of the rabbits inoculated with 7710 cells also contained HVS DNA and, after in vitro culture, induced the same type of lymphoma when inoculated into two other III/J-strain rabbits. None of the previously described HVS-transformed cell lines have been able to induce tumors in either their host species or nude mice. Thus, our demonstration that the 7710 cell line is readily transplantable in syngeneic rabbits represents the first available model which allows analysis of many biological and molecular aspects of the in vivo oncogenicity of HVS.

Animals↗
PubMed1985

Transfer of reactivity with in vitro produced transfer factor in rhesus and owl monkeys.

Transfer factors against two heterologous antigens, Herpesvirus saimiri and owl monkey kidney cells, were replicated in vitro in a human lymphoblastoid cell line (LDV/7) and injected into rhesus and owl monkeys. Transfer of immunity was demonstrated by the leukocyte migration inhibition assay. This study suggests that heterologous transfer factor, replicated in vitro, can transfer cellular immunity against membrane antigens in rhesus and owl monkeys.

Animals↗
PubMed1984

Interaction of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) with owl monkey kidney cells in enhancing the yields of Herpesvirus saimiri (HVS) and its antigens.

Pre- and posttreatment with N-methyl-N'-nitro-nitrosoguanidine (MNNG) of owl monkey kidney (OMK) cells infected with Herpesvirus saimiri (HVS) resulted in one to three logs higher yields of virus, depending upon the dose of MNNG. A higher percentage of cells also showed HVS early antigen (EA) and late antigen (LA) by immunofluorescence when OMK cells infected with HVS were fed with medium containing MNNG. The high yields of HVS were also observed by electron microscopy. MNNG did not induce HVS-EA in HVS nonproducer lymphoblastoid T cells, nor did it enhance TPA-induced EA to LA. The data suggest that MNNG could be useful in obtaining high yields of virus and/or antigen-producing cells for immunofluorescence or other biochemical experiments, especially from those strains of HVS which grow poorly in vitro. The interaction of MNNG and HVS could also be useful for in vitro transformation or in vivo enhancement of the malignant process.

Animals↗