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61.
Tiziano Dall'Occo Franco Sartori Giancarlo Vecellio Umberto Zucchini Andrea Maldotti 《Macromolecular chemistry and physics.》1993,194(1):151-161
As a part of our interest in the performance of [Ti2(OC2H5)8Cl]2Mg2(μ-Cl)2 as Ziegler-Natta catalyst, the polymerization of styrene with a toluene solution of this compound and methyl-aluminoxane as cocatalyst was performed. It was found that the present catalytic system promotes the syndiospecific polymerization of styrene with high stereoregularity and the results were compared with those obtained with MgCl2-supported or unsupported Ti(OC2H5)4 catalysts. Determination of the titanium oxidation states and electron spin resonance (ESR) measurements both in the absence and in the presence of styrene were carried out for all the catalytic systems aimed at shedding some light on the nature of the active species. 相似文献
62.
Douglas M. Strong John R. Ortaldo Franco Pandolfi Annette Maluish Ronald B. Herberman 《Journal of clinical immunology》1982,2(3):214-221
Cryopreserved human peripheral blood mononuclear cells (PBMC) were tested for natural killer (NK) and antibody-dependent cellular cytotoxicity (ADCC) and for high-affinity (29°C) and total (4°C) rosette formation with sheep erythrocytes. PBMC produced variable NK activity following freezing and thawing, but consistently reacted well in ADCC. A significant correlation was found between low NK activity and a decreased percentage of low-affinity rosette-forming cells. On the contrary, the number of large granular lymphocytes (LGL), among which NK cells are restricted, and the reactivity with the monoclonal antibody OKT10, which recognizes the majority of LGL in the peripheral blood, were not significantly altered by cryopreservation. Cryopreserved cells proved to be excellent controls for determining the day-to-day variability of the NK assay and for selecting optimum conditions for this test in the clinical immunology laboratory. 相似文献
63.
Taborda CP Nakaie CR Cilli EM Rodrigues EG Silva LS Franco MF Travassos LR 《Scandinavian journal of immunology》2004,59(1):58-65
The 43 kDa glycoprotein (gp43) of Paracoccidioides brasiliensis is the major diagnostic antigen of paracoccidioidomycosis (PCM), a prevalent fungal infection in South America. A 15-mer sequence from gp43, denominated P10, induced T-CD4+ T helper 1 cellular immune responses in mice of three different haplotypes and protected against intratracheal challenge by a virulent isolate of P. brasiliensis. In an attempt to improve delivery of P10, a promiscuous antigen also presented by human leucocyte antigen-DR alleles, aiming at immunotherapy, we synthesized a multiple antigen peptide with the protective T-cell epitope expressed in a tetravalent 13-mer analog of P10 (M10). M10 induced specific lymph node cell proliferation in mice preimmunized with peptides in complete Freund's adjuvant (CFA). In addition, M10 immunization without CFA significantly protected intratracheally infected mice. We conclude that M10 is a candidate for an anti-PCM vaccine. In this report we describe: (1) the synthesis of M10; (2) the induction of M10-elicited T-cell response and (3) in vivo protection of mice immunized with M10 and challenged by a virulent strain of P. brasiliensis. 相似文献
64.
Rolla G Nebiolo F Marsico P Guida G Bigo P Riva G Zanotta S 《International archives of allergy and immunology》2004,135(4):293-295
BACKGROUND: The European tick, Argas reflexus, is an urban pest parasitizing urban pigeons and may cause a wide range of allergic reactions. METHODS: Specific IgE to A. reflexus, SDS-PAGE and IgE immunoblotting, performed with tick extract, were carried out in the sera of 6 patients who reported allergic reactions after tick bite. RESULTS: Specific IgE to A. reflexus (RAST class ranging from 1 to 3) were detected in the sera of 6 patients who reported allergic reactions (urticaria and angioedema in 2 and anaphylaxis in the other 4 patients) after tick bite. IgE reactivity to two bands of 22 and 40 kDa were identified in the patient sera. CONCLUSIONS: Allergy to A. reflexus has to be considered in allergic patients living in buildings where pigeons have their nests. The powerful sensitizing property of tick allergen is underlined by the observation that none of our patients was atopic. 相似文献
65.
Cauci S Thorsen P Schendel DE Bremmelgaard A Quadrifoglio F Guaschino S 《Journal of clinical microbiology》2003,41(1):435-438
A nested case-control study of low birth weight and preterm delivery was performed with singleton women. Immunoglobulin A (IgA) against the Gardnerella vaginalis hemolysin (anti-Gvh IgA) and sialidase and prolidase activities were determined in vaginal fluid at 17 weeks of gestation. Sialidase positivity and bacterial vaginosis with high prolidase activity were associated with 2- and 11-fold increased risks for low birth weight, respectively. No woman with bacterial vaginosis plus a strong anti-Gvh IgA response had an adverse outcome. 相似文献
66.
Ungari M Pellegrini W Borlenghi E Marocolo D Ubiali A Agazzi C Pich A Franco V Facchetti F 《Pathologica》2002,94(6):325-330
Detection of atypical megakaryocytes in bone marrow biopsies, especially in cases of myelodysplastic syndromes (MDS), chronic myeloproliferative disorders (CMPD) and acute leukemias, is facilitated by staining for markers such as Ulex europaeus agglutinin (UEA)-J, CD31, CD61 and von Willebrand factor (VWF), the latter being considered the most sensitive. Recently, LAT (linker for activation of T cells), a molecule involved in T-cell activation and platelet aggregation, was found to be expressed by megakaryocytes and platelets in tissue sections. We compared VWF and LAT immunoreactivity on megakaryocytes in 64 bone marrow biopsies from 12 normal controls (NC), and from patients with MDS (n=18), CMPD (n=21) and acute megakaryocytic leukemia (AML-M7, n=13). Immunostaining was performed on paraffin sections with polyclonal antibodies against VWF and LAT. Immunoreactivity was evaluated by counting positive megakaryocytes in 10 high-power fields, and values were compared using Student's t test for paired data. Both VWF and LAT predominantly stained the cytoplasm of megakaryocytes, although LAT was also recognizable on the cell membrane. In most biopsies, the immunoreactivity of the two antibodies was quite similar. No significant differences were noticed between the mean values of VWF+ and LAT+ megakaryocytes. However, in 22 cases (5 NC; 5 MDS; 6 CMPD; 6 AML-M7), the number of LAT+ megakaryocytes was at least 30% higher than VWF+cells, while in 3 cases opposite findings were found. In 3 AML-M7 cases, anti-LAT antibodies stained numerous megakaryocytes, but anti-VWF staining was practically negative; in another 5 AML-M7 cases, anti-LAT labeling was much stronger than anti-VWF staining. LAT represents a useful immunohistochemical marker for megakaryocytes in normal and pathological conditions. It seems to be expressed by megakaryocytes more than VWF in most cases and, particularly, in conditions associated with poorly differentiated megakaryocytes, such as acute megakaryocytic leukemias. The use of LAT staining should be recommended in association with other megakaryocyte markers in the study of bone marrow biopsies in cases of hematopoietic disorders. 相似文献
67.
Production of type II heat-labile enterotoxin by Escherichia coli isolated from food and human feces. 总被引:8,自引:4,他引:8 下载免费PDF全文
B E Guth C L Pickett E M Twiddy R K Holmes T A Gomes A A Lima R L Guerrant B D Franco L R Trabulsi 《Infection and immunity》1986,54(2):587-589
Escherichia coli strains isolated in Sao Paulo, Brazil, from feces of patients with diarrhea and from food samples produced toxin(s) that was shown to be related both immunologically and genetically to the recently characterized type II heat-labile enterotoxin of E. coli. The new isolates of type II heat-labile enterotoxin-producing E. coli belonged to five different serotypes and did not represent a single clone. 相似文献
68.
Mylne Lesnchal Laurence Becquart Xavier Lacoux Laurent Ladavire Renata C. P. Baida Glaucia Paranhos-Baccal Jos Franco da Silveira 《Clinical and Vaccine Immunology : CVI》2005,12(2):329-333
Tc40 is an immunodominant antigen present in natural Trypanosoma cruzi infections. This immunogen was thoroughly mapped by using overlapping amino acid sequences identified by gene cloning and chemical peptide synthesis. To map continuous epitopes of the Tc40 antigen, an epitope expression library was constructed and screened with sera from human chagasic patients. A major, linear B-cell epitope spanning residues 403 to 426 (PAKAAAPPAA) was identified in the central domain of Tc40. A synthetic peptide spanning this region reacted strongly with 89.8% of the serum samples from T. cruzi-infected individuals. This indicates that the main antigenic site is defined by the linear sequence of the peptide rather than a conformation-dependent structure. The major B-cell epitope of Tc40 shares a high degree of sequence identity with T. cruzi ribosomal and RNA binding proteins, suggesting the existence of cross-reactivity among these molecules. 相似文献
69.
Mapping antigenic sites of an immunodominant surface lipoprotein of Mycoplasma agalactiae, AvgC, with the use of synthetic peptides 下载免费PDF全文
As a first step toward the design of an epitope vaccine to prevent contagious agalactia, the strongly immunogenic 55-kDa protein of Mycoplasma agalactiae was studied and found to correspond to the AvgC protein encoded by the avgC gene. The avg genes of M. agalactiae, which encode four variable surface lipoproteins, display a significant homology to the vsp (variable membrane surface lipoproteins) genes of the bovine pathogen Mycoplasma bovis at their promoter region as well as their N-terminus-encoding regions. Some members of the Vsp family are known to be involved in cytoadhesion to host cells. In order to localize immunogenic peptides in the AvgC antigen, the protein sequence was submitted to epitope prediction analysis, and five sets of overlapping peptides, corresponding to five selected regions, were synthesized by Spot synthesis. Reactive peptides were selected by immunobinding assay with sera from infected sheep. The three most immunogenic epitopes were shown to be surface exposed by immunoprecipitation assays, and one of these was specifically recognized by all tested sera. Our study indicates that selected epitopes of the AvgC lipoprotein may be used to develop a peptide-based vaccine which is effective against M. agalactiae infection. 相似文献
70.
Aldo Scarpa Franco Bonetti Fabio Menestrina Marta Menegazzi Marco Chilosi Maurizio Lestani Chiara Bovolenta Giuseppe Zamboni L. Fiore-Donati 《Virchows Archiv : an international journal of pathology》1987,412(1):17-21
Summary The Southern blot hybridization technique has been applied to study the configuration of immunoglobulin and T-cell receptor genes in 6 cases of the so called mediastinal large cell lymphoma with sclerosis. This lymphoma has been recently recognized as a separate entity among non-Hodgkin lymphomas mainly affecting young adult patients. The B-cell origin of this neoplasm was suggested by means of immunohistochemical analysis. However, the immunophenotypical B-cell related markers used do not always exhibit lineage fidelity. The Southern blot analysis demonstrated the presence of unique heavy and k-light chain immunoglobulin gene rearrangements, establishing genotypically their B-cell origin.This work was supported by the Associazione Italiana per la Ricerca sul Cancro, Milano, Italy, and Progetto finalizzato Oncologia (contratto no 86.00461.44), CNR, Rome, Italy. Aldo Scarpa and Maurizio Lestani are supported by a Scholarship from the Associazione Italiana per la Ricerca sul Cancro, Milano, Italy 相似文献