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Biomedical subjects

A Siracusano

Publications and source records attributed to A Siracusano.

At least 37 records · Page 2Linked to original sources
PubMed1999

Pneumocystis carinii infection in young non-immunosuppressed rabbits. Kinetics of infection and of the primary specific immune response.

The aim of this study was to determine the kinetics, the dissemination of the infection and the immunological response to Pneumocystis carinii primary infection in a non-immunosuppressed rabbit model. For this purpose, we developed a nested PCR that amplified a portion of the mitochondrial large-subunit rRNA gene of rabbit-derived P. carinii. The PCR detected P. carinii DNA in lung and bronchoalveolar lavage fluids from 14- to 45-day-old rabbits but not in their serum. No P. carinii DNA was detected in extrapulmonary organs from 28-day-old rabbits with P. carinii pneumonia. ELISA and immunoblotting analysis showed that 5-day-old pups had elevated specific IgG. The IgG concentration sharply decreased, reaching a trough on day 21, and from then onwards progressively increased as the infection cleared. Conversely, the specific IgM concentration increased during the infection and peaked on day 28. IgG mainly recognized a 50-kDa subunit of P. carinii organisms; IgM recognized first a 45-kDa subunit on day 21, whereas from day 28 onwards it also recognized the 50-kDa subunit. A P. carinii-specific splenocyte proliferative response was observed on day 45. These findings suggest that P. carinii primary infection is a time-limited and a lung-limited event and contribute new information on the relationship between the kinetics of primary P. carinii infection and the immunological response in a model that mimics the primary infections in humans.

Aging↗
PubMed1999

Serum cytokine detection in the clinical follow up of patients with cystic echinococcosis.

The relation of serum cytokine levels and outcome of chemotherapy was evaluated in 15 patients with cystic echinococcosis. Serum IL-4, IL-10 and interferon-gamma (IFN-gamma) concentrations were determined by ELISA before and after a 3-month course of albendazole treatment: at least one serum sample per patient from 13 patients (87%) contained measurable amounts of IL-4; samples from five patients (33%) measurable amounts of IL-10 and samples from only two patients (13%) measurable amounts of IFN-gamma. Clinical assessment at 1 year after the end of therapy showed that 11 of the 15 patients had responded clinically. Seven of these patients had lower IL-4 serum concentrations, two had unchanged and two undetectable amounts (pre- versus post-therapy, n = 11, P = 0.008). Conversely, of the patients who did not respond, three had higher and one patient unchanged serum IL-4 concentrations. Serum IL-10 10 levels also decreased in all patients who responded (3/5) and increased in all patients who did not (2/5). No association was found between cytokine concentrations and cyst characteristics or antibody levels. Overall these data suggest that serum IL-4 detection may be useful in the follow up of patients with cystic echinococcosis.

Adult↗
PubMed1999

Cytokine gene expression in peripheral blood mononuclear cells (PBMC) from patients with pharmacologically treated cystic echinococcosis.

The influence of pharmacological treatment on the immune response of patients with Echinococcus granulosus infection was evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) to determine mRNA expression for IL-12 p35, IL-12 p40, interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha) and IL-4 in PBMC from 12 patients before and after chemotherapy and from seven uninfected controls. Most patients' PBMC showed measurable amounts of IL-12 p35, IL-4, IFN-gamma and TNF-alpha mRNA in parasite antigen-stimulated and unstimulated cultures. Conversely, IL-12 p40 mRNA was detected almost exclusively in successfully treated patients (86%) after therapy. In these patients semiquantitative analysis of RT-PCR products showed a significant difference between IL-12 p40 mRNA mean levels before and after therapy (P = 0.03 in parasite antigen-stimulated cultures; P = 0.001 in unstimulated cultures). IL-4 mRNA was weakly expressed before therapy and more highly so after treatment in both groups of patients and under both culture conditions; IL-4 mRNA reached its highest level in post-therapy PBMC from patients in whom therapy failed (stimulated cultures). IFN-gamma and TNF-alpha mRNA expression increased in patients who responded to therapy and decreased in patients who did not. In contrast to IL-12 p35, IFN-gamma and TNF-alpha mRNAs, IL-12 p40 and IL-4 mRNAs were detected exclusively in patients, suggesting a close relationship between these two cytokines and cystic echinococcosis. Our findings indicate that chemotherapy influences the immune response, thus determining changes in Th1/Th2 cytokine mRNA patterns, predominantly in IL-12 p40 and IL-4 mRNA expression.

Adult↗
PubMed1999

Cloning and expression of a cDNA encoding an elongation factor 1beta/delta protein from Echinococcus granulosus with immunogenic activity.

A cDNA clone (Eg EF-1beta/delta) of Echinococcus granulosus has been isolated by an expression library screened with immunoglobulin (Ig)E of sera from patients with cystic echinococcosis (CE). The Eg EF-1beta/delta was identified on the basis of sequence homology to the subunits beta or delta of the elongation factor-1. The amino acid sequence deduced from this open reading frame is 244 residues long with a predicted molecular mass of 31 kDa. In Southern blot under high stringent condition, Eg EF-1beta/delta hybridized to genomic DNA of E.granulosus at two bands of 4 and 2.5 Kb. In immunoblotting analysis, the Eg EF-1beta/delta protein shows immunological reactivity with sera from CE patients: 51.7% of sera contained IgE, 41.7% IgG and 18.3% IgG4 specific to the recombinant protein. We identify the Eg EF-1beta/delta by immunoblotting with specific monoclonal antibody both in protoscoleces and in sheep hydatid fluid. The higher percentage of humoral immune response against Eg EF-1beta/delta observed in CE patients with calcified cysts than in patients with active cysts indicates the possible release of the protein in the hydatid fluid after protoscoleces degeneration suggesting the possible use of this antigen in the immunosurveillance of CE. Overall, these findings seem to assign to Eg EF-1beta/delta a key role in the allergic disorders and in the complex host-parasite relationship in CE.

Allergens↗
PubMed1999

Immunochemical and molecular characterization of vertebral hydatid fluid.

This study describes a 42-year-old male born in Tunisia, who presented with vertebral hydatidosis which was initially misdiagnosed as Pott's disease. The correct diagnosis was finally made utilizing CT and MRI imaging and confirmation of the diagnosis was made possible by molecular and immunochemical characterization of the content of vertebral cyst fluid.

Adult↗
PubMed1998

Cytokine patterns in seropositive and seronegative patients with Echinococcus granulosus infection.

To investigate the involvement of immunological variables, including the Th1/Th2 balance, in the mechanisms underlying seronegativity in cystic echinococcosis (CE), Th1 and Th2 cytokines were evaluated in ELISA determining IFN-gamma, IL-4, -5 and -10 production in peripheral blood mononuclear cell (PBMC) cultures from 16 patients (six seronegative and ten seropositive) with CE and from six healthy donors. Patients who had undetectable antibody levels in their sera invariably produced no IL-5 and scarce IL-4 and -10 (Th2 response); both groups of patients produced similar amounts of IFN-gamma; (Th1 response). The analysis of host clinical features and cyst characteristics shows that these variables do not explain the lack of detectable serum antibody levels. These findings suggest that seronegativity arises because unknown host or parasite factors, or both, cause inadequate Th2 cell activation thus reducing production of Th2 cytokines, including IL-5, the cytokine primarily implicated in immunoglobulin expression in CE.

Adult↗
PubMed1998

Potential impact of Pneumocystis genetic diversity on the molecular detection of the parasite in human host.

Our aim was to evaluate if genetic diversity of Pneumocystis carinii could influence the detection by molecular techniques in bronchoalveolar lavage (BAL) fluids and in non-invasive specimens (induced sputum, oropharyngeal washing and serum/blood). P. carinii is morphologically similar in different hosts although several strains have been identified by biomolecular techniques. Variations of mt-LSU and ITSs sequences could determine a lack of hybridization of some clinical samples and could have diagnostic consequences with loss in sensitivity and specificity of available molecular tests, but at the moment no data support a significant impact of genetic diversity in these sequences on molecular detection of P. carinii for clinical purposes.

DNA Primers↗
PubMed1997

Biodiversity of Pneumocystis carinii hominis: typing with different DNA regions.

The purpose of this study was to identify the most useful gene for the detection of biodiversity of Pneumocystis carinii hominis isolates and to compare samples from French and Italian subjects. We studied 20 bronchoalveolar lavage fluid specimens from 20 human immunodeficiency virus-infected patients (10 French and 10 Italian patients) with Pneumocystis carinii pneumonia by DNA sequencing of the thymidylate synthase (TS), 5S rRNA, large-subunit mitochondrial rRNA (mt LSU rRNA), and internal transcribed spacer (ITS1 and ITS2) genes. Thirteen of the 20 sequenced samples had the prototype TS gene sequence. Fourteen of the 20 samples showed the prototype sequence of the 5S rRNA gene, and 6 had variant sequences of the 5S rRNA gene. The mt LSU rRNA gene was sequenced for 18 of the 20 samples; all sequences were different from the prototype sequence and were classified into four groups. Thirteen of the 20 ITS1 and ITS2 sequences were analyzed, and all the sequences were found to be different from the prototype sequence and were classified into 10 groups. The internal transcribed spacer regions thus appear to be the most discriminatory region of DNA for analysis of the biodiversity of P. carinii hominis isolates.

AIDS-Related Opportunistic Infections↗
PubMed1997

Detection of Pneumocystis carinii in respiratory specimens by PCR-solution hybridization enzyme-linked immunoassay.

By using a recently developed PCR-solution hybridization enzyme-linked assay (PCR-SHELA), we investigated Pneumocystis carinii in bronchoalveolar lavage fluid samples and induced sputa of patients with pneumocystosis. In detecting P. carinii, PCR-SHELA proved more sensitive than immunofluorescence staining or a single PCR and significantly more diagnostically specific than a nested PCR. Our data suggest that PCR-SHELA could be used to detect P. carinii organisms in respiratory samples, particularly in patients with uncertain diagnoses.

AIDS-Related Opportunistic Infections↗
PubMed1997

New perspectives in the immunology of Echinococcus granulosus infection.

This article reviews the role of cytokines and immunoglobulin isotypes in the clinical outcome of E. granulosus infection. The coexistence of elevated quantities of IFN-gamma, IL-4, IL-5, IL-6 and IL-10 observed in most of hydatid patients supports Th1 and Th2 cell activation in human hydatidosis. In particular, Th1 cell activation seems to be related to protective immunity, Th2 cell activation to susceptibility to disease. Analysis of immunoglobulin isotypes expression reveals that the percentage of IgE responses decreases in patients parallelling to their response to chemotherapy and, among the IgG isotypes, only IgG3 and IgG4 appear related to therapy.

Animals↗
PubMed1996

Non specific PCR products using rat-derived Pneumocystis carinii dihydrofolate reductase gene-specific primers in DNA amplification of human respiratory samples.

DNA amplification using dihydrofolate reductase (DHFR) primers in bronchoalveolar lavage fluids (BALFs) from patients with Pneumocystis carinii (PC) pneumonia yielded low sensitivity and specificity. Amplified products of BALFs from an AIDS patient without PC pneumonia and five patients with PC pneumonia were cloned and sequenced. All samples showed the same sequence without any homology with DHFR cDNA of rat PC, or with any DHFR sequences in databases at the DNA or amino acid level. The data demonstrate that these DHFR primers amplify a non-specific region of DNA with a sequence unrelated to the human PC DHFR gene both in PC positive and in PC negative samples. This finding precludes the use of these DHFR primers for the diagnosis of PC pneumonia in respiratory specimens.

Base Sequence↗
PubMed1996

Production of IL-5 and IL-6 by peripheral blood mononuclear cells (PBMC) from patients with Echinococcus granulosus infection.

The role of Th2 cytokines in human hydatidosis was evaluated in ELISA determining IL-5 and IL-6 production in PBMC cultures from 27 pharmacologically treated hydatid patients and from 13 uninfected controls. PBMC from patients produced large amounts of parasite antigen-driven IL-5, whereas PBMC from uninfected individuals produced none. In contrast, PBMC from patients and from uninfected controls produced large amounts of parasite antigen-driven IL-6. Immunoglobulin isotype analysis revealed that IL-5 production correlated significantly with IgE and IgG4 expression (IL-5/IgE r = 0.5, P < 0.05; IL-5/IgG4 r = 0.6, P < 0.05). The high IL-5 levels in supernatants from patients' PBMC did not correspond to an increase in eosinophils. Neither IL-5 nor IL-6 production showed an association with the outcome of therapy. Overall, these findings confirm that the lymphocytes of individuals with Echinococcus granulosus infection contain Th2-like subpopulations.

Albendazole↗
PubMed1996

Immunological responses to antigen B from Echinococcus granulosus cyst fluid in hydatid patients.

The immunological reactivity of Echinococcus granulosus antigen B was evaluated in 30 hydatid patients. Antigen B was purified from sheep hydatid cyst fluid by electroelution from a non-reducing SDS-PAGE gel (AgB). In ELISA and immunoblotting (IB), determining antibody production in sera from patients with hydatid disease and with other parasitic infections, purified AgB showed higher specificity than a partially purified antigen named pH5PPT (100% vs 83% in pH5PPT-ELISA and 58% in pH5PPT-IB). AgB-IB achieved higher sensitivity than AgB-ELISA (80% vs 63%). All AgB-IB positive sera recognized the 12 kDa subunit. Qualitative AgB-IB assessment of IgG isotype responses identified IgG4 as the predominant isotype (87%). The other isotypes showed a lower percentage of positive reactions: IgG1, 33%; IgG2, 21%; and IgG3, 17%. PBMC proliferative assay revealed a cellular response to AgB in 100% of patients' PBMC. These findings confirm antigen B, especially its smallest subunit, as a good diagnostic molecule.

Animals↗
PubMed1996

Imbalance between Pneumocystis carinii cysts and trophozoites in bronchoalveolar lavage fluid from patients with pneumocystosis receiving prophylaxis.

Detection and quantification of different Pneumocystis carinii (PC) life cycle forms were performed by polymerase chain reaction (PCR) and by morphological stains on bronchoalveolar lavage fluids (BALF) from HIV-infected patients with P. carinii pneumonia (PCP). The number of PC trophozoites was higher in patients with PCP who were receiving prophylaxis than in those not receiving prophylaxis. Also the cyst: trophozoite ratio was lower in the first group. No difference was observed between patients receiving different prophylactic medications. The imbalance between PC forms in BALF from patients with PCP receiving anti-PC prophylaxis may hamper the sensitivity of cyst stains. Multiple stains or PCR examination should be performed on BALF from patients with clinically suspected PCP who are receiving prophylaxis.

AIDS-Related Opportunistic Infections↗
PubMed1996

Genetic variability in Italian sheep isolates of Echinococcus granulosus.

The possible polymorphism of distinct Italian Echinococcus granulosus isolates was evaluated by RAPD-PCR using five arbitrarily chosen random primers. Sheep DNA was used as control in each RAPD-PCR to ascertain the host DNA contamination. Distinct amplification patterns were detected for each isolate revealing identical bands, with the same or different intensity, as well as distinct bands. The results of this study confirm the usefulness of RAPD-PCR technique in genetic typing of parasites and show the existence of genetic variability within the Italian E. granulosus sheep strain.

Animals↗
PubMed1995

Variable efficiency of three primer pairs for the diagnosis of Pneumocystis carinii pneumonia by the polymerase chain reaction.

The efficiency of three different primer pairs, complementary to different Pneumocystis carinii DNA regions, was compared in the polymerase chain reaction (PCR) for the diagnosis of Pneumocystis carinii pneumonia (PCP) on bronchoalveolar fluid (BALF) from patients with AIDS. PCR coupled with dot-blot hybridization (BLOT) using primers and probe from the mitochondrial 23SrDNA region showed the highest sensitivity, with a lower detection limit of 0.5-1 organisms microliter-1. When testing 47 BALF, PCR plus BLOT of the mitochondrial 23SrDNA region showed also the best diagnostic efficiency (97% sensitivity, 100% specificity). Sensitivity was significantly higher than with PCR and BLOT of the 5SrDNA region (81.5% sensitivity; P = 0.025, McNemar test); and of the dehydrofolate reductase (DHFR) gene region (75.6% sensitivity; P = 0.019). Sensitivity was also significantly higher than indirect immunofluorescence (75.8% sensitivity; P = 0.008). Using DHFR primers and probe, specificity was also reduced. The diagnostic sensitivity in clinical specimens paralleled the detection limit in the standard dilutions. The use of repeated DNA sequences of proven specificity as target of PCR amplification favourably influences sensitivity and specificity. This comparative study demonstrates that primer selection plays a significant role in the diagnosis of PCP by PCR.

AIDS-Related Opportunistic Infections↗