Biomedical subjects

A Ruggieri

Publications and source records attributed to A Ruggieri.

At least 19 recordsLinked to original sources

PubMed2005

Synthesis, assembly, and processing of the Env ERVWE1/syncytin human endogenous retroviral envelope.

Syncytin is a fusogenic protein involved in the formation of the placental syncytiotrophoblast layer. This protein is encoded by the envelope gene of the ERVWE1 proviral locus belonging to the human endogenous retrovirus W (HERV-W) family. The HERV-W infectious ancestor entered the primate lineage 25 to 40 million years ago. Although the syncytin fusion property has been clearly demonstrated, little is known about this cellular protein maturation process with respect to classical infectious retrovirus envelope proteins. Here we show that the cellular syncytin protein is synthesized as a glycosylated gPr73 precursor cleaved into two mature proteins, a gp50 surface subunit (SU) and a gp24 transmembrane subunit (TM). These SU and TM subunits are found associated as homotrimers. The intracytoplasmic tail is critical to the fusogenic phenotype, although its cleavage requirements seem to have diverged from those of classical retroviral maturation.

Amino Acid Sequence↗

PubMed2003

Cell cycle perturbation in a human hepatoblastoma cell line constitutively expressing Hepatitis C virus core protein.

Hepatitis C virus (HCV) is one of the major causes of chronic liver disease with the potential for development of hepatocellular carcinoma (HCC). The core protein of HCV has been shown to modulate expression of various cellular genes and to influence a number of cellular functions. We investigated the effect of constitutively expressed HCV core protein on cell cycle progression in HepG2 cell line, which is derived from a differentiated human hepatoblastoma and shows biosynthetic features similar to human hepatocytes. The results indicated that stable expression of the core protein in unsynchronized HepG2 cells induced a perturbation of the cell cycle with reduced cell doubling meantime and increased S phase fraction. Increase of c-myc protein above the basal expression level was demonstrated with a significant increase of c-myc stability, as revealed by its prolonged intracellular half-life, in HepG2 expressing HCV core protein. In contrast, p53 and p21 levels were unchanged. These results suggest that HCV core protein may promote cell cycle progression in HepG2 cells possibly through increasing stability of c-myc oncoprotein. These results are in support of important role played by HCV core protein in virus-mediated pathogenesis in persistently infected hosts and in hepatocarcinogenesis.

Cell Cycle↗

PubMed2003

Induction of FAS ligand expression in a human hepatoblastoma cell line by HCV core protein.

Tumour cells and virus infected cells expressing Fas ligand (FasL) can evade immune surveillance by inducing apoptosis in T cells expressing Fas. In order to characterise a possible role of hepatitis C virus (HCV) core protein in similar mechanisms during HCV infection, we investigated Fas ligand expression and activity in a human hepatoblastoma cell line (HepG2) constitutively expressing this protein. Strong FasL induction was detected by immunoblotting and flow cytometry analysis in the core expressing cell lines Hep39. In contrast, vector transfected cells or cell lines expressing HCV E1-E2 proteins did not show FasL expression. Co-cultivation experiments of Hep39 cells with a Fas-sensitive T cell line indicated that FasL induced by the core protein had apoptotic activity toward target cells. Effect of the core protein on induction of FasL promoter was further examined by co-transfection of HepG2 cells with core-bearing plasmid and a vector in which luciferase gene expression is driven by human FasL promoter. Results of the luciferase assay indicated a positive regulation of FasL promoter by the core protein. In conclusion, HCV core protein plays a role in the induction of functional FasL in hepatoblastoma cell line and apoptosis in a target T cell line expressing Fas. Similar mechanisms may contribute, in vivo, to establishment of chronic infection and development of hepatocellular carcinoma (HCC).

Apoptosis↗

PubMed2000

Adenosine triphosphate affects interleukin -1beta release by T98G glioblastoma cells through a purinoceptor-independent mechanism.

T98G glioblastoma cells were previously shown to significantly increase interleukin-1beta (IL-1beta) mRNA levels in response to IL-1beta stimulation. This work demonstrates that in such conditions T98G, despite possessing biologically active interleukin converting enzyme, do not release detectable amounts of IL-1beta, even in the presence of 20 mM adenosine triphosphate (ATP). IL-1beta secretion is observed only following concomitant stimulation with 1000 units/ml of IL-1beta and 20 mM ATP. ATP induces a dose-dependent depolarization of T98G plasma membrane, whereas it does not affect Ca(2+) concentration or cell membrane permeability. Our data, together with the observation that the depolarizing effects of ATP are retained after preincubation with 100 microM suramin, an antagonist of P2-purinoceptors, suggest that ATP plays a role in IL-1beta secretion by T98G but its effects do not occur through P2-purinoceptors.

Adenosine Triphosphate↗

PubMed2000

Activation of a cell entry pathway common to type C mammalian retroviruses by soluble envelope fragments.

Mutations that negatively or positively affect the fusion properties of murine leukemia viruses (MLVs) have been found within all subdomains of their SU (surface) and TM (transmembrane) envelope units. Yet, the interrelations between these different regions of the envelope complex during the cell entry process are still elusive. Deletion of the histidine residue of the conserved PHQV motif at the amino terminus of the amphotropic or the ecotropic MLV SU resulted in the AdelH or the MOdelH fusion-defective mutant envelope, respectively. These delH mutant envelopes are incorporated on retroviral particles at normal densities and normally mediate virion binding to cells expressing the retroviral receptors. However, both their cell-cell and virus-cell fusogenicities were fully prevented at an early postbinding stage. We show here that the fusion defect of AdelH or MOdelH envelopes was also almost completely reverted by providing either soluble SU or a polypeptide encompassing the receptor-binding domain (RBD) to the target cells, provided that the integrity of the amino-terminal end of either polypeptide was preserved. Restoration of delH envelope fusogenicity was caused by activation of the target cells via specific interaction of the latter polypeptides with the retrovirus receptor rather than by their association with the delH envelope complexes. Moreover crossactivation of the target cells, leading to fusion activation of AdelH or MOdelH envelopes, was achieved by polypeptides containing various type C mammalian retrovirus RBDs, irrespective of the type of entry-defective glycoprotein that was used for infection. Our results indicate that although they recognize different receptors for binding to the cell surface, type C mammalian retroviruses use a common entry pathway which is activated by a conserved feature of their envelope glycoproteins.

Animals↗

PubMed2000

A randomized controlled trial of concept based indexing of Web page content.

OBJECTIVE: Medical information is increasingly being presented in a web-enabled format. Medical journals, guidelines, and textbooks are all accessible in a web-based format. It would be desirable to link these reference sources to the electronic medical record to provide education, to facilitate guideline implementation and usage and for decision support. In order for these rich information sources to be accessed via the medical record they will need to be indexed by a single comparable underlying reference terminology. METHODS: We took a random sample of 100 web pages out of the 6,000 web pages on the Mayo Clinic's Health Oasis web site. The web pages were divided into four datasets each containing 25 pages. These were humanly reviewed by four clinicians to identify all of the health concepts present (R1DA, R2DB, R3DC, R4DD). The web pages were simultaneously indexed using the SNOMED-RT beta release. The indexing engine has been previously described and validated. A new clinician reviewed the indexed web pages to determine the accuracy of the automated mappings as compared with the human identified concepts (R4DA, R3DB, R2DC, R1DD). RESULTS: This review found 13,220 health concepts. Of these 10,383 concepts were identified by the initial human review (78.5% +/- 3.6%). The automated process identified 10,083 concepts correctly (76.3% +/- 4.0%) from within this corpus. The computer identified 2,420 concepts, which were not identified by the clinician's review but were upon further consideration important to include as health concepts. There was on average a 17.1% +/- 3.5% variability in the human reviewers ability to identify the important health concepts within web page content. Concept Based Indexing provided a positive predictive value (PPV) of finding a health concept of 79.3% as compared with keyword indexing which only has a PPV of 33.7% (p < 0.001). CONCLUSION: SNOMED-RT is a reasonable ontology for web page indexing. Concept based indexing provides a significantly greater accuracy in identifying health concepts when compared with keyword indexing.

Abstracting and Indexing↗

PubMed1998

CXC chemokines interleukin-8 (IL-8) and growth-related gene product alpha (GROalpha) modulate Purkinje neuron activity in mouse cerebellum.

We give here evidence that Purkinje neurons (PNs) of mouse cerebellar slices studied with patch clamp technique combined with laser confocal microscopy, respond to human IL-8 and GROalpha by (i) a cytosolic Ca2+ transient compatible with inositol (1,4,5) trisphosphate (InsP3) formation; (ii) an enhancement of the neurotransmitter release; and (iii) an impairment of the long-term depression of synaptic strength (LTD). It was also found the expression of IL-8 receptor type 2 in PN and granule cells by immunofluorescence, immunoblotting and RT-PCR analysis. Considered together these findings suggest that IL-8 and GROalpha may play a neuromodulatory role on mouse cerebellum.

Animals↗

PubMed1997

Sensitization to Fas-mediated apoptosis by hepatitis C virus core protein.

We have characterized viral-cell interactions of hepatitis C virus (HCV) and liver cells to study the pathogenesis of HCV infection. HepG2 cells constitutively expressing HCV core protein showed apoptotic changes in response to stimulation with anti-Fas monoclonal antibody. Cells treated with the antibody showed extensive cell rounding, shrinkage, and cytoplasmic blebbing and finally detached from plates. Fragmentation of the chromatin was observed in the nucleus and DNA ladders were detected. In contrast, cells expressing HCV envelope, nonstructural proteins or normal HepG2 cells did not exhibit such Fas-mediated apoptosis. However, expression of Fas receptor was not upregulated on the surface of the cells expressing HCV core protein. Apoptotic cell death was prevented by pretreatment with a specific inhibitor of the cysteine protease CPP32, while the specific inhibitor of interleukin-1 beta-converting enzyme did not show the preventive effect. The results suggest (i) that intracellular expression of HCV core protein makes cells prone to apoptotic death without upregulation of surface Fas expression and (ii) that the CPP32 protease plays a part in the apoptosis effector pathway of HCV core-expressing cells. HCV core protein may have a role in immune-mediated liver cell injury.

Apoptosis↗

PubMed1996

Heterogeneity of hepatitis C virus genotype 2 variants in West Central Africa (Guinea Conakry).

An overall anti-hepatitis C virus (HCV) prevalence of 6.7% was found in a sero-epidemiological study carried out in the town of Conakry (Guinea Conakry, West Central Africa) on 1421 subjects who were either blood donors, pregnant women or in- and outpatients receiving treatment for conditions other than liver disease. Seven HCV isolates from a subsample of 73 sterile sera from this population were studied for genetic characterization and classification. The 5'NCR was analysed by the Line Probe Assay. This method assigned the isolates to genotype 2. Analysis of the 5'NCR sequences alone was unable to give a more accurate classification. Comparison of NS5b region sequences (nucleotides 7575-8196), from Guinea isolates and genotype 2 database sequences, showed evolutionary distances in the range 0.15-0.26. There was a high level of subtype heterogeneity among the genotype 2 Guinea HCV isolates. Four of the subtypes were possibly new.

Base Sequence↗

PubMed1994

Pharmacokinetics of zidovudine in HIV-positive patients with liver disease.

The pharmacokinetics of zidovudine (ZDV) have been studied in eight AIDS patients with normal liver function, and in four AIDS patients with liver disease. Patients who were previously untreated with ZDV were given 250 mg ZDV, and plasma levels of ZDV and its glucuronic metabolite, GZDV, were determined at 0.5, 1, 1.5, 2, 3, and 4 hours after the dose. In patients with liver disease, Cmax and AUC of ZDV were higher, the oral clearance was only one-eighth that of patients without liver disease, and the elimination half-life was longer. There was a trend for concentrations of the principal metabolite, GZDV, to be lower in patients, and, therefore, the ratio of the AUC for GZDV to that for ZDV was much lower in patients with liver disease. Therefore, HIV-seropositive patients with liver disease had the same markedly altered disposition of ZDV as seronegative patients with liver disease. Although this therapy was not clearly associated with a higher incidence of toxicity, some patients with liver disease had to discontinue therapy because of intolerance; therefore, plasma levels of these patients should be monitored when such therapy is undertaken.

Adult↗

PubMed1994

Antigenic and sequence analysis of H3 influenza virus haemagglutinins from pigs in Italy.

To investigate the possible mechanism of maintenance of old human influenza A (H3N2) viruses in pigs, the haemagglutinins (HAs) of seven isolates from swine were studied by analysis of nucleotide and deduced primary amino acid sequences, as well as reactivity of the HA molecule to chicken antisera and monoclonal antibodies. The swine HAs were closely similar to the HA of the A/Victoria/3/75 human variant as regards antigenic and molecular characteristics. These findings are consistent with the hypothesis that the swine HA genes were transmitted from an early human H3 virus to pigs, where they survived with limited mutations over a period of 5 years. The sequence data were also compared with swine H3 sequences to investigate genetic relationships between the H3 genes from swine viruses isolated in different geographical areas. An evolutionary tree, constructed from the nucleotide sequences of viruses isolated from pigs in China and in Italy, illustrated that, depending on the country of their isolation, the HA genes of swine influenza A (H3N2) viruses have different origins, e.g. human and avian, and evolved independently in different lineages. The study provides direct support for the hypothesis that pigs might serve as a 'mixing vessel' for the generation of pandemic strains of human influenza viruses.

Amino Acid Sequence↗

PubMed1993

Concurrent antigenic analysis of recent epidemic influenza A and B viruses and quantitation of antibodies in population serosurveys in Italy.

Laboratory investigations of virus isolation and serum antibodies in a Mediterranean country (Italy) demonstrated that influenza A and B viruses, and often both, circulated every winter in Italy. The winter 1987/88 was characterized by a low level of influenza activity, as shown by the limited number (47) of influenza virus isolates, the majority of which (61%) belonged to the influenza B type. In contrast, the 1988/89 influenza season was exclusively associated with the circulation of influenza type A viruses. The A(H1H1) subtype was largely predominant (97%), as compared to the low incidence of the A(H3N2) subtype (3%). During the 1989/90 winter a co-circulation of A and B influenza viruses was observed, A(H3N2) strains being responsible for 96% of the virologically confirmed cases. Antigenic analysis of the virus isolates showed some antigenic variation in influenza A viruses of both H1N1 and H3N2 subtypes, whilst antigenic stability was found among the influenza B virus isolates. Overall, the above virological findings correlate with the data concerning the pattern of influenza virus circulation in Northern Europe and the UK during the three years surveyed. The results of serum antibody surveys conducted in each post-epidemic period are also reported.

Adolescent↗

PubMed1993

Long-term treatment with zidovudine in patients with human immunodeficiency virus (HIV)-associated thrombocytopenia: modes of response and correlation with markers of HIV replication.

The effects of zidovudine on the platelet count were studied in 152 patients with HIV-related thrombocytopenia of severe grade (platelet count < 50 x 10(9)/l) and moderate grade (platelet count < 100 and > 50 x 10(9)/l). In both groups of patients there was a significant increase in the mean platelet count from the baseline value, after 2 weeks (from 21 x 10(9)/l to 48 x 10(9)/l and from 75 x 10(9)/l to 97 x 10(9)/l) and 3 months of therapy (to 59 x 10(9)/l and to 144 x 10(9)/l). Sixty-five and 39 patients were followed up for 12 and 18 months, respectively, and the mean platelet values after 12 and 18 months of therapy were still significantly increased, compared to the respective mean baseline values, in both groups of patients. Clinical progression of the disease was observed in 23 treated patients, none of them showing concomitant reductions of the platelet number. An increase in the mean CD4+ cell count after 3 months of therapy was followed by a progressive decline in the 65 patients with a 12-month follow-up, while no significant changes of the p24 antigenemia rates were observed after 1 year of therapy in 53 patients evaluated. The long-term effects of zidovudine on the platelet count, but not on other parameters of clinical outcome, might be explained by the involvement of specific mechanisms in the pathogenesis of this kind of thrombocytopenia and of its response to zidovudine.

Acquired Immunodeficiency Syndrome↗

PubMed1991

Detection of two antigenic subpopulations of A(H1N1) influenza viruses from pigs: antigenic drift or interspecies transmission?

Serological analysis of a group of 63 influenza H1N1 viruses isolated from pigs in Italy in the period 1976-1988 revealed the presence of two distinct antigenic subpopulations: some viruses possessed a haemagglutinin indistinguishable from that of viruses typically associated with pigs, i.e., A/New Jersey/8/76 (H1N1), whereas others showed a close antigenic relatedness with the haemagglutinin of avian-like H1 viruses. These findings represent further evidence that influenza A viruses from avian species may be transmitted to mammals. The surface and internal proteins of some of these viruses were also analyzed biochemically to evaluate the molecular relatedness among viruses circulating in non-human hosts.

Animals↗

PubMed1991

First recovery of A/equine/Fontainebleau/1/79 influenza viruses in Italy.

In Italy epizootics of equine influenza often occur, but no virus isolation has been reported since 1971. This paper describes the antigenic and biochemical characterization of two equine influenza viruses isolated in Italy from 1985 to 1989. The virus isolates were shown to differ antigenically from earlier strains of the same subtype, A/equine/Miami/1/63 (H3N8). Monoclonal antibody analysis showed that the haemagglutinins of these strains were serologically indistinguishable from A/equine/Fontainebleau/1/79, a variant of A/equine/Miami, never isolated in Italy before. One of the two virus isolates was obtained from a horse immunized with a bivalent inactivated influenza vaccine, not containing A/equine/Fontainebleau/79 antigens. The vaccine failure underlines the importance of antigenic relatedness between currently circulating viruses and vaccine strains. Therefore, to improve the protection afforded by equine immunization, the vaccine composition should be decided according to the results of a virological surveillance activity, systematically conducted among horses.

Animals↗

PubMed1990

An experimental in vitro model for evaluating drugs against protoscoleces of Echinococcus granulosus.

Pharmacological studies carried out on protoscoleces in vitro to standardize conditions that would permit a preliminary estimate of the efficacy of drugs with potential activity against Echinococcus granulosus are reported. Media such as PBS and Hanks solution, maintenance temperature, different pH values and concentrations of various solvents have been tested to check the effects on protoscolex survival in tubes in vitro. Mebendazole has been used as the pharmacological standard reference. Changes in the viability of protoscoleces have been used to demonstrate pharmacological activity. Best conditions were obtained employing Hanks solution and propylene glycol at low concentrations. Mebendazole was not completely effective at the concentrations achievable in human therapy. Linear, reproducible results demonstrated that Hanks solution provides an ideal medium for pharmacological studies. Among tested solvents, propylene glycol and dimethyl sulphoxide showed no lethal activity at low concentrations. At concentrations similar to those normally obtained in human sera, mebendazole, as in vivo, demonstrated only partial lethality for protoscoleces. The present study represents a new experimental approach to chemotherapy of hydatid disease.

Animals↗

PubMed1989

Influenza vaccination in elderly residents in nursing homes: immune response to trivalent and monovalent inactivated influenza virus vaccine in the season 1986-87.

Immune responses to trivalent inactivated whole virus and monovalent subunit influenza vaccines, used in the season 1986-87, were analyzed in elderly residents in nursing homes. Higher levels of induced antibody were found in the group receiving two doses of trivalent vaccine. This suggests that high risk aged patients should receive a booster dose of vaccine annually. The antibody response to administration of supplemental vaccination, using monovalent subunit preparation, did not reach the high level of antibodies found following trivalent influenza vaccine.

Aged↗

PubMed1988

Surveillance of influenza A and B viruses in Italy between 1984 and 1987.

Antigenically heterogeneous strains and new variants of influenza A viruses, both A (H3N2) and (H1N1) subtypes, as well as influenza B strains were detected in Italy in a period, between 1984-1987, characterized by a moderate degree of influenza activity. Each year the evaluation, by SRH technique, of antibodies, in the population, to currently circulating viruses, has confirmed the extent of infection and often the prevalent virus.

Adolescent↗