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G Damiani

Publications and source records attributed to G Damiani.

At least 55 records · Page 3Linked to original sources
PubMed1991

Identification of a new motif on nucleic acid sequence data using Kohonen's self-organizing map.

Here we present a performance test of a Kohonen features map applied to the fast extraction of uncommon sequences from the coding region of the human insulin receptor gene. We used a network with 30 neurons and with a variable input window. The program was aimed at detecting unique or uncommon DNA regions present in crude sequence data and was able to automatically detect the signal peptide coding regions of a set of human insulin receptor gene data. The testing of this program with HSIRPR cDNA release (EMBL data bank) indicated the presence of unique features in the signal peptide coding region. On the basis of our results this program can automatically detect 'singularity' from crude sequencing data and it does not require knowledge of the features to be found.

Algorithms↗
PubMed1991

Limited clonal heterogeneity of antigen-specific T cells localizing in the pleural space during mycobacterial infection.

To detect possible differences in phenotype and fine specificity for mycobacterial antigens between CD4-positive T cells from peripheral blood (PB) and from inflammatory sites, we identified four patients presenting with a mycobacterial pleural exudate (PE) rich in PPD-specific lymphocytes and with a negative skin test to tuberculin purified protein derivative (PPD) and a negative proliferative response of PB lymphocytes to PPD at the same time. Several weeks after chemotherapy, these patients converted to PPD responsiveness in the periphery, and PPD-specific clones could be generated from PB at this stage. The phenotypic comparison of PE lymphocytes and concomitant PB lymphocytes obtained before treatment showed an increase of CD8 cells and a high frequency of HLA-DR-positive activated T cells in PE. The frequency of tetanus toxoid-specific and Candida albicans-specific proliferating T cells was lower than that of PPD-specific cells in PE but not in PB. PPD-specific clones were derived initially from PE and from PB once the patients had converted to PPD responsiveness. The two sets of clones from each patient were compared for proliferative response to mycobacterial antigen clusters of defined molecular weight ranges. A large number of PE-derived clones (36%) responded to a fraction of 27 to 35 kDa, whereas only one clone from PB responded to the same fraction. The purified antigen P32 (32 kDa), a soluble mycobacterial protein, stimulated PE-derived clones that were responsive to the 37- to 27-kDa fraction but did not stimulate PB-derived clones. The data demonstrate that PE- and PB-derived lymphocytes differ both in phenotype and in fine specificity, suggesting a limited clonal heterogeneity of T cells localizing at the inflammatory site in tuberculous patients without a PPD response in the periphery. Therefore T cells compartmentalized at inflammatory sites provide information that is different from that provided by T cells in the periphery.

Antigens, Bacterial↗
PubMed1991

[The radiological pictures of pulmonary tuberculosis in HIV+ patients].

Mycobacterial infections can be found in 10% of AIDS patients. Seventy cases with HIV+ infection were examined: they exhibited clear alterations of the chest and contemporaneous isolation and identification of mycobacteria. Primary tuberculosis is the most frequent manifestation in these patients. Alveolar parenchymal mono/bilateral infiltrates are the radiographic patterns of this pulmonary condition; they usually present without excavation (45.7%). Hilar and/or mediastinal lymph nodes are usually associated, and no pleural effusions. The main problem is the differential diagnosis with pneumocystis carinii pneumonia, especially the form involving lung apices. A correlation has been observed between the blood level of T-lymphocytes and their subsets (CD4 level) and the radiographic patterns of tuberculosis in AIDS patients. In fact, pleural effusion is frequent in patients with CD4 less than 200, while miliary nodules and cavitations are more frequent in the cases with CD4 greater than 200.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Response to Mycobacterium tuberculosis antigens is enhanced by monoclonal antibodies.

T lymphocytes purified from peripheral blood of tuberculosis patients and from healthy skin test PPD-positive subjects show a remarkably increased proliferative response in culture to purified protein derivative (PPD) when three anti-mycobacterial monoclonal antibodies are added together with the antigen. This indicates an important role played by antibodies in the T cell response to the tuberculous infection.

Antibodies, Bacterial↗
PubMed1990

The risks of early cordocentesis (12-21 weeks): analysis of 500 procedures.

Five hundred cordocenteses were performed between 12 and 21 weeks. The indications were thalassaemia (386), rapid karyotyping (97), feto-maternal allo-immunization (10), rubella (6), and toxoplasmosis (1). One hundred and ten pregnancies underwent termination on the basis of the result, while 20 of the 370 pregnancies intended to continue were lost to follow-up. Amongst these were 16 fetal losses (4.3 per cent) and 22 premature deliveries (5.9 per cent); no other complications were reported. Four adverse prognostic factors were identified: (a) cord bleeding; (b) fetal bradycardia; (c) prolonged procedure time; and (d) anterior insertion of the placenta. There was no 'obvious' difference in fetal loss rate with advancing gestation until 19-21 weeks, when the risk of fetal loss decreased to 2.5 per cent.

Blood Specimen Collection↗
PubMed1990

Restriction fragment length polymorphism analysis of the kappa-casein locus in cattle.

The two common genetic variants (A and B) of bovine kappa-casein originate from two point mutations in the codons for the aminoacids in position 136 and 148. These mutations give rise to polymorphic sites for the restriction endonucleases Hin dIII, AluI, HinfI, Mbo II and TaqI. We have examined DNAs of several Italian Friesian cows and bulls of known and unknown genotype by Southern analyses using kappa-casein cDNA probes. Restriction fragment length polymorphisms (RFLPs) specific for the A and B alleles were identified for each of the above enzymes, except for AluI, which has a non-polymorphic site 12bp away from the polymorphic one. We have also found two new polymorphic sites for MboII and TaqI in the non-coding regions. These sites differentiate the A allele into two new variants, named A1 and A2. The RFLP analysis permits the characterization of kappa-casein alleles even in the absence of their expression. This should facilitate selective breeding programmes aimed at increasing the frequency of the kappa-casein B allele whose product improves the cheesemaking properties of milk.

Amino Acid Sequence↗
PubMed1990

Identification of a 35-kilodalton Mycobacterium tuberculosis protein containing B- and T-cell epitopes.

Screening of a Mycobacterium tuberculosis genomic DNA library in the lambda gt11 expression vector was carried out by using, as probes, sera from tuberculous patients and murine monoclonal antibody H61.3 recognizing a mycobacterial 35-kilodalton protein present only on the M. tuberculosis complex. The recombinant beta-galactosidase-fused protein present in the crude lysate induced the proliferation of T lymphocytes from patients with tuberculous pleuritis. As the recombinant insert contains an internal EcoRI restriction site, it was possible to identify two fragments, one proximal to the lacZ gene and 1.7 kilobases (kb) in size and the other distal to the lacZ gene and 2.2 kb in size. Southern blot analysis showed that both of them hybridized with the genomic DNA from M. tuberculosis and M. bovis but not with the DNA from other mycobacterial species. To perform extensive immunological studies, the amount of beta-galactosidase-fused protein being very low, we fused the 1.7-kb fragment to the N-terminal part of the gene coding for the DNA polymerase of bacteriophage MS2 in the expression vector pEx34. The fusion protein was partially purified, and subsequent Western blotting (immunoblotting) and T-cell proliferation experiments confirmed the presence of B- and T-cell mycobacterial epitopes. Furthermore, to isolate the chromosomal region containing the 35-kilodalton gene, we constructed another mycobacterial genomic library in the lambda 2001 vector by cloning 15 to 20 kb of foreign DNA. Screening of this library was carried out by using 1.7- and 2.2-kb recombinant fragments as probes. Restriction maps of some clones isolated were determined.

Antigens, Bacterial↗
PubMed1990

A procedure for cloning restriction fragments of DNA as single inserts in yeast artificial chromosomes.

A novel procedure is described for the cloning of partial EcoRI fragments of bovine DNA: it reduces the chance of sequence rearrangements due to multiple insertions (co-cloning) of restriction fragments in the resulting YAC. The DNA to be inserted has been dephosphorylated, whereas the matching ends of the vector, pYAC4, have not. The ligation was essentially complete, the transformation efficiency was close to 19 transformants per ng of vector and the frequency of clones carrying YAC, 60-100 kb in size, was close to 70%. The YACs show segregative and replicative stability.

Animals↗
PubMed1989

A simple, rapid method for screening hybridomas producing monoclonal antibodies to platelet proteins.

Several parameters influence the outcome of somatic cell fusions based on the Köhler and Milstein technology, and a number of steps are of critical importance, including the screening strategy. The procedure chosen, appropriate for the type of antibody required, should be rapid and sensitive, in order to clone the relevant hybrids as quickly as possible. A simple and quick dot blot-based method is reported, suitable for screening hybridoma culture supernatants in order to identify clones producing monoclonal antibodies to platelet constituents.

Animals↗
PubMed1989

Antipeptide antibodies toward the extracellular domain of insulin receptor beta-subunit.

In order to investigate structure and function of beta-subunit extracellular portion, four polyclonal antibodies (AP1, AP2, AP3 and AP4) toward peptides comprised in this region were generated. None of them recognizes native human and rat insulin receptor both in vitro and in whole cells. Two antibodies, AP1 and AP2, immunoprecipitate isolated (DTT-reduced) human beta-subunits and bind to human IM-9 cell after alpha-subunit tryptic cleavage. Only AP1 recognizes rat beta-subunit both in vitro and in trypsin treated rat FAD cells. These findings suggest that: (i) the extracellular portion of the insulin receptor beta-subunit is partially covered by the alpha-subunit in human and rat native insulin receptors; (ii) human and rat beta-subunit extracellular domains are different, at least in the amino acid sequence corresponding to residues 785-796 of the human insulin receptor.

Amino Acid Sequence↗
PubMed1989

Cloning of histidine genes of Azospirillum brasilense: organization of the ABFH gene cluster and nucleotide sequence of the hisB gene.

A cluster of four Azospirillum brasilense histidine biosynthetic genes, hisA, hisB, hisF and hisH, was identified on a 4.5 kb DNA fragment and its organization studied by complementation analysis of Escherichia coli mutations and nucleotide sequence. The nucleotide sequence of a 1.3 kb fragment that complemented the E. coli hisB mutation was determined and an ORF of 624 nucleotides which can code for a protein of 207 amino acids was identified. A significant base sequence homology with the carboxy-terminal moiety of the E. coli hisB gene (0.53) and the Saccharomyces cerevisiae HIS3 gene (0.44), coding for an imidazole glycerolphosphate dehydratase activity was found. The amino acid sequence and composition, the hydropathic profile and the predicted secondary structures of the yeast, E. coli and A. brasilense proteins were compared. The significance of the data presented is discussed.

Amino Acid Sequence↗
PubMed1989

Immunohistologic analysis of mycobacterial antigens by monoclonal antibodies in tuberculosis and mycobacteriosis.

Four monoclonal antibodies (MoAbs), 60.15, 61.3, 105.10, and 2.16, directed to different proteins of Mycobacterium tuberculosis were used by an indirect avidin-biotin complex peroxidase-antiperoxidase method to detect mycobacterial antigens in lung, lymph node, and joint tissue specimens of tuberculous patients. Using MoAb 60.15, which recognizes a broad range of cross-reactive mycobacterial proteins with a molecular mass of 28 kilodaltons (kD), scattered materials (mycobacterial in origin) were observed, many of which were located within phagocyte cytoplasm. With MoAb 61.3, which reacts with a 35 kD protein present in M tuberculosis, Mycobacterium africanum, and Mycobacterium bovis, many clumped particles similar in size and shape to acid-fast bacilli were observed within the phagocyte cytoplasm (lung tissue) and positive macrophages with lysosomes were distributed throughout the cytoplasm (bronchoalveolar lavage). The specificity of this MoAb (61.3) was confirmed by the negative staining of positive lymph node specimens obtained from a patient infected with Mycobacterium kansasii. MoAbs 105.10 and 2.16 bind to the cross-reactive 65 kD heat shock protein that is present in mycobacteria and stain scattered particles and dark clumps of bacilli within the phagocyte cytoplasm. On the basis of this study, immunohistochemical detection of mycobacterial antigens appears to be useful in establishing the mycobacterial etiology of caseating granulomas and in avoiding the false-negative results obtained by traditional staining methods.

Antibodies, Monoclonal↗
PubMed1989

Characterization of Sicilian strains of spotted fever group rickettsiae by using monoclonal antibodies.

Twenty-two hybridomas producing anti-Rickettsia conorii monoclonal antibodies were obtained by nine fusion experiments. The strain chosen for immunization of mice was MAVI, an R. conorii strain isolated from a Sicilian patient with Boutonneuse fever. When tested for immunoglobulin isotype by an indirect immunofluorescence (IIF) assay, 46.6% of supernatants from the 22 hybridomas were immunoglobulin M. The supernatants were tested in the IIF assay for binding to the MAVI strain and four spotted fever group rickettsia strains isolated from Sicilian ticks (two virulent and two nonpathogenic when inoculated intraperitoneally in male guinea pigs). Only five of the supernatants showed a positive IIF result on all tested strains, although they produced different titers to the various strains, possibly an indication that they recognized an antigen common to spotted fever group rickettsiae. Immunodominant epitopes for humans were determined by using patient sera to analyze inhibition of binding to the MAVI strain. Although a limited number of serum samples were screened, a high percentage of Boutonneuse fever patients produced antibodies recognizing the same epitopes as were recognized by the mouse monoclonal antibodies. A striking heterogeneity was found both in the expression of mouse-recognized epitopes on the five rickettsial strains and in the serum antibody responses of Boutonneuse fever patients to these epitopes.

Adult↗
PubMed1989

Analysis of Mycobacterium tuberculosis genoma and production of a recombinant protein containing specific B and T cell antigenic determinants--new approaches to second generation antituberculosis vaccines.

Tuberculosis is still a major health problem in almost all over the world. Thus, new directions in basic and applied research of tuberculosis are under investigation in several laboratories. In this paper, we provide recent data obtained in our laboratory with the recombinant DNA technology which allow a systematic survey of the microbial genome. Screening of the M. tuberculosis genomic DNA library in the phage lambda gt11 expression vector, using E. coli as surrogate host, has evidenced the possibility of producing recombinant M. tuberculosis proteins recognized by sera from tuberculosis patients and by specific monoclonal antibodies. Using this technology, we have isolated a recombinant protein (molecular weight 130 kilodaltons) which is identified by a murine monoclonal antibody recognizing a mycobacterial cell wall antigenic determinant present on a mycobacterial protein. This protein is only present on the mycobacterial species related to the tuberculosis complex (M. tuberculosis, M. bovis, M. africanum) and does not crossreact with nonpathogenic Mycobacteria. Since the immune response to mycobacterial infections is cell-mediated, the question arises about the use of M. tuberculosis-specific T lymphocytes to screen this gene bank. Thus, the recombinant mycobacterial protein isolated by antibodies has been then used to stimulate the proliferation of T lymphocytes from patients with tubercular pleuritis. This experiment indicates that the recombinant protein contains antigenic determinants recognized by T cells. Moreover, such protein is able to elicit delayed type hypersensitivity skin reaction in mice immunized or infected with M. tuberculosis and M. bovis. Finally, gene mapping and hybridization studies with native M. tuberculosis DNA confirme the mycobacterial nature of the recombinant DNA insert. Thus a good candidate for the prophylaxis and the immunodiagnosis of tuberculosis has been identified. The identification and selection of genes encoding antigenic determinants recognized by mycobacteria-specific T cells with protective functions will allow in the near future the construction by genetic engineering of recombinant vaccines effective in the control of this disease. This paper will briefly discuss the present strategy used in our laboratory to reach this goal.

Animals↗
PubMed1989

The role of macrophages and lymphocytes in bronchial asthma: perspectives for new research models.

The role played by macrophages and lymphocytes in allergic asthma is certainly important, since memory and specificity for the allergen are functions typically carried out by such immune cells. However, study of the effect of allergens on macrophages and lymphocytes has been hampered by the lack of suitable in vitro or in vivo models. Bronchoalveolar lavage cells, which undergo important modifications in asthma, represent only part of the cell types involved in the pathogenesis of this disease. The possible integrated use of recombinant DNA, monoclonal antibodies, T-cell clones and continuous cell lines, together with a better understanding of the activation states of phagocytes, could lead to advances both in the understanding and in the treatment of allergic asthma.

Asthma↗
PubMed1989

Can pregnancy aggravate the course of non-Hodgkin's lymphoma?

The Authors present three cases of Non-Hodgkin's Lymphoma (NHL) in pregnancy and discuss about problem of diagnosis and management of NHL in this condition. They stress that the diagnosis of NHL in pregnancy is delayed and the clinical progression of lymphoma is probably influenced by hormonal and immunological changes occurring during pregnancy. On the other hand the management of NHL is problematic because radiotherapy is potentially teratogenic. (By editorial staff).

Adult↗
PubMed1989

Oxidative metabolism of human peripheral blood eosinophils and neutrophils: H2O2 production after stimulation with phorbol myristate acetate and immune complexes.

Eosinophils like neutrophils possess an oxidative metabolism which is activated by phagocytosis and cell membrane activation. Since eosinophils may take part in inflammatory reactions by releasing oxygen species and have membrane receptors for immunoglobulins, immune complexes may activate their respiratory burst. We compared the ability of phorbol myristate acetate (PMA) and immunoglobulin G (IgG) and immunoglobulin E (IgE) immune complexes to stimulate hydrogen peroxide (H2O2) release from circulating eosinophils and neutrophils. PMA was able to stimulate a significant respiratory burst in both cell types, PMA-induced H2O2 production being higher in eosinophils than in neutrophils (p less than 0.05). Similar results were obtained when the cells were stimulated by IgG (p less than 0.05). In contrast, aggregated human myeloma IgE induced a detectable H2O2 release only from peripheral blood eosinophils. We conclude that H2O2 release from eosinophils may play a role in parenchymal injury associated with hypereosinophilic disorders and the presence of immune complexes at sites of disease activity.

Adult↗