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Biomedical subjects

G Motta

Publications and source records attributed to G Motta.

At least 73 records · Page 4Linked to original sources
PubMed1994

Characterization and cellular localization by monoclonal antibodies of the 60 kDa mannose specific lectin of human promyelocytic cells, HL60.

Myelomonocytic lineage cells express an M(r) 60,000 mannose specific lectin, MR60 (Pimpaneau et al. (1991), Carbohydr Res 213: 95-108). Under non-reducing conditions, this protein migrates as a 120,000 protein. MR60 does not contain any N-glycan moiety cleavable by the action of N-glycanase. MR60 induces a sugar selective aggregation of beads coated with glycosylated albumin: beads bearing alpha-D-mannosyl residues are aggregated while beads bearing alpha-D-glucosyl residues are not. A monoclonal antibody Lec101B, specific for MR60, recognizes a single M(r) 60,000 protein by Western blotting. This monoclonal antibody does not label the cell surface of cells expressing MR60, but decorates intracellular vesicles upon permeabilization of these cells.

Agglutination Tests↗
PubMed1994

Dye-hydrophobic hapten conjugate/anti-dye antibody complex as immunogen: preparation of hydrophobic hapten-specific monoclonal antibodies.

In order to induce the production of antibodies specific for small molecules, it is common to link them to a protein. However, when the small molecule is very hydrophobic it is extremely difficult to prepare such a conjugate. Here, we describe a simple way to obtain an antigenic conjugate under controlled conditions: in a first step a very hydrophobic hapten, cholanic acid, is linked to a dye, basilen blue, in organic solvent; in a second step the cholanic acid-basilen blue conjugate is dissolved in phosphate buffered saline and mixed with rabbit polyclonal anti-basilen blue antibodies previously raised in rabbits against basilen blue-key-hole limpet hemocyanin conjugate. Such a complex, which dissociates very slowly, appears to be a good immunogen in mice. Anti-cholanyl residue monoclonal antibodies were produced and characterized.

Animals↗
PubMed1994

Immunoactivity of pidotimod against episodes of recurrent tonsillitis in childhood.

The therapeutic efficacy of the synthetic immunostimulant pidotimod ((R)-3-[(S)-(5-oxo-2-pyrrolidinyl) carbonyl]-thiazolidine-4-carboxylic acid, PGT/1A, CAS 121808-62-6) was evaluated in a double-blind placebo-controlled study in parallel groups in the management of recurrences in 235 children with recurrent tonsillitis. The ambulant study provided for 15 days of treatment with two oral vials of pidotimod 400 mg or placebo daily, in accordance with a randomisation list, 60 days of treatment with one oral vial of pidotimod 400 mg or placebo daily, and a 90-day follow-up period. The total trial period was 165 days. In addition to evaluating the number of tonsillitis recurrences which occurred during the 75 days of treatment and the 90-day follow-up period, the number of days on which the principal symptoms of the illness were present and on which drugs such as antibiotics or anti-inflammatory agents were used concomitantly, as well as the number of days' absence from school, were analyzed. The findings showed that, taking the treatment phase and the three-month follow-up period together, pidotimod significantly reduces the incidence of inflammatory upper airways episodes. The very low incidence of adverse effects, which was the same as that in the placebo group, confirmed the excellent safety of the product.

Adjuvants, Immunologic↗
PubMed1993

Further approaches to the quaternary structure of octopus hemocyanin: a model based on immunoelectron microscopy and image processing.

The direction of the polypeptide chains and the location of the functional units in Octopus vulgaris hemocyanin were studied by various methods. Monoclonal antibodies specific for the Ovc (clone Ov409) and Ovg (clone Ov315) functional units produced immunocomplex strings which were examined in the electron microscope. In both cases the immunocomplexes contained more than two hemocyanin molecules in their side view, demonstrating that in the whole hemocyanin neighboring polypeptide chains run in antiparallel directions. The interhemocyanin distances in the immunocomplexes also indicated that Ovg is located inside the cylinder, while Ovc is located in the external layers of functional units. In addition, the fact that the binding point of the Fab arm to the hemocyanin molecule was occasionally visible confirmed the external location of functional unit Ovc. Image processing of the whole hemocyanin cross-linked with dimethyl suberimidate showed that the end-on view is not a perfect cylinder but a regular pentahedron and that the five-arch collar is probably composed of five pairs of functional unit Ovg located inside the cylinder. The accessibility of cross-linked hemocyanin to functional unit-specific polyclonal antibodies, studied in immunoelectrophoresis, showed that Ovb and Ove are highly accessible, while Ovd, Ovf, and Ovg are not. The low accessibility of Ovd may be at least partially explained by its high sugar content which could hamper the accessibility of the antibody to the antigen.

Animals↗
PubMed1993

Immunotherapy with intralesional and systemic interleukin-2 of patients with non-small-cell lung cancer.

Eight patients affected by non-small-cell lung cancer were treated with intralesional and systemic recombinant IL-2 (rIL-2) injection with the aim of activating both tumour-infiltrating lymphocytes and circulating cytotoxic or killer cells. The schedule of treatment was as follows: a daily fine-needle transparietal intralesional rIL-2 injection (1 x 10(5) Cetus units) from day 1 to day 5 and systemic rIL-2 infusion (1 x 10(5) Cetus units kg-1 day-1) from day 6 to day 10. One to four cycles of treatment were received by each patient. Clinical and immunological evaluations were performed (a) before treatment, (b) following the intralesional rIL-2 administration, (c) 1 h after the beginning of rIL-2 infusion and (d) at the end of the systemic rIL-2 infusion. No complete remission was achieved, two patients showed a partial remission, three resulted in stable disease and three patients progressed. Natural killer and lymphokine-activated killer cell activity dramatically decreased 1 h after the beginning of rIL-2 infusion and increased at the end of treatment. A progressive increase of circulating CD8+ and HLA class II+ T cells as well as of CD8+ T cell clones, most of which displayed NK activity, was recorded following rIL-2 infusion. Present data indicate that (a) the local administration of rIL-2 coupled with systemic rIL-2 infusion may be suggested as an alternative approach for the immunotherapy of lung cancer, (b) rIL-2 induces different immunological modifications according to the route and the time of its administration and (c) rIL-2 administration increases the amount of circulating immune cells with potential antitumour activity.

Carcinoma, Non-Small-Cell Lung↗
PubMed1992

Human plasma kallikrein processing: proteolysis as an alternative control.

Human plasma kallikrein (HuPK) was detected in normal non-activated and dilution-activated plasma by immunoblotting, using polyclonal antibodies. In non-activated plasma, the predominatly detected protein corresponds to prokallikrein (Mr 80,000-90,000). Activated plasma, besides kallikrein, contains larger proteins (Mr > 130,000) that possibly represent complexes between kallikrein and proteinase inhibitors. Plasma also contains species (Mr 43,000) which corresponds to kallikrein heavy chain. In activated plasma, monoclonal antibodies against kallikrein heavy chain detected, besides these same bands described above, two additional bands (Mr 30,000 and 20,000) possibly correspondent to fragments of kallikrein heavy chain.

Antibodies↗
PubMed1992

Allergic rhinoconjunctivitis: diagnostic and clinical assessment.

In allergic rhinoconjunctivitis not only the nasal mucosa but also the conjunctiva and, in severe cases, the cornea are affected by reactive phenomena. This pathological process is often encountered in clinical practice, its incidence ranging from 10% to 30% of the whole population, as reported by many authors. Up to now, the pathogenetic mechanisms of allergic reactivity are not completely understood. In our opinion this is due to insufficient standardization of the diagnostic procedures; even the clinical picture of such a pathological process seems to be insufficient, especially with regard to the analogies between the nasal and conjunctival pathologies. To a great extent this depends on the different clinical pictures both in otorhinolaryngology and ophthalmology. Our study has been carried out on 98 patients suffering from rhinoconjunctivitis, and presents an accurate documentation with regard to the existence of analogies in reactivity at the immunoallergic level, in both the nose and conjunctiva. These are evident when we refer not only to specific routine allergological tests but, mainly, to local examinations. The evaluation of the selected data enables us to formulate a single classification of allergic rhinoconjunctivitis, taking into account the common reactive phenomena.

Adult↗
PubMed1992

Action of plant proteinase inhibitors on enzymes of the kallikrein kinin system.

Serine proteinase inhibitors, in the seeds of several Leguminosae from the Pantanal region (West Brazil), were studied using bovine trypsin, Factor XIIa and human plasma kallikrein. The inhibitors were purified from Enterolobium contortisiliquum (Mr = 23,000), Torresea cearensis (Mr = 13,000), Bauhinia bauhinioides (Mr = 20,000), Bauhinia mollis (Mr = 20,000) and Bauhinia pentandra (Mr = 20,000). E. contortisiliquum inhibitor inactivates all three enzymes, whereas the T. cearensis inhibitor inactivates trypsin and Factor XIIa, but does not affect plasma kallikrein. B. bauhinioides and B. pentrandra inhibitors, on the other hand, inactivate trypsin and plasma kallikrein but only the B. pentandra inhibitor affects Factor XIIa, and B. mollis inhibitor causes trypsin inactivation only. Calculated Ki values were between 10(-7) and 10(-9) M. Chymotrypsin, like trypsin, is also inhibited, but with lower affinity. The trypsin inhibitors, isolated from E. contortisiliquum, B. pentandra, B. bauhinioides and B. mollis seem to be of the Kunitz type; the inhibitor purified from T. cearensis is of the Bowman-Birk type.

Brazil↗
PubMed1992

Human plasma kallikrein. Immunoreactivity and activity on natural and synthetic substrates.

Human plasma kallikrein (HuPK) is a serine protease found in mammalian plasma. Following limited proteolysis, the enzyme is activated and forms two chains. The light chain occurs with molecular weight 36,000 or 33,000 and contains the active site. The heavy chain occurs with molecular weight of 45,000 and contains the binding site for high-molecular-weight kininogen. Both chains were prepared from active HuPK, following mild reduction with dithiothreitol and carboxymethylation with iodoacetamide. The light chain was isolated in SBTI-Sepharose and its kinetic properties were determined with synthetic derivatives of arginine-p-nitroanilides, to investigate any possible alteration of the active site. These studies showed that substrate modifications affected the hydrolytic activity more than the binding capacity. The ability to cleave high-molecular-weight kininogen, as observed for intact kallikrein, was reduced in beta-kallikrein and absent in the light chain, even when equimolar amounts of both light and heavy chains were tested together. Anti-kallikrein antiserum formed immunoprecipitates not only with kallikrein itself, but also with the separated chains. The immunoreactivity of the light-chain was not identical with that of kallikrein. Immunoselected specific antibodies for both chains, depending on the selectivity, reacted with the heavy chain and kallikrein, or with the light chain and kallikrein. These antibodies were shown to be effective in binding radio-iodinated HuPK in the radioimmunoassay developed for intact kallikrein.

Amino Acid Sequence↗
PubMed1990

Topological mapping of 13 epitopes on a subunit of Androctonus australis hemocyanin.

A topological localization of epitopes on the surface of the Aa6 subunit of Androctonus australis hemocyanin has been carried out. First, immunocomplex strings composed of native hemocyanin and monoclonal antibodies were examined in the electron microscope and submitted to an image processing by correspondence analysis. The average images were then compared to a three-dimensional model of the 24-mer suggesting that 11 of the 13 epitopes are located in three zones of the subunit surface. Second, the overlaps between the epitopes were then studied by polyacrylamide gel electrophoresis, competitive binding inhibition, and immunoelectron microscopy. Four groups of epitopes were identified. One group was capable of binding exclusively to the free subunit. The other three groups were identical to those found in immunoelectron microscopy. The data are consistent with the existence of a small number of immunodominant regions on the surface of the Aa6 subunit.

Animals↗
PubMed1990

Prognostic value of the Jass histopathologic classification in left colon and rectal cancer: a multivariate analysis.

Variables correlated to survival were studied in 121 patients who had undergone potentially curative surgery for left colon and rectal cancer. To investigate the prognostic value of the parameters both univariate and multivariate analysis were carried out. Minimum follow-up was 5 years. Multivariate analysis showed that while disease stage (p less than 0.0001) and site of primary tumor (p less than 0.0006) independently influenced survival, type of surgical procedure and histopathologic grade had no impact on survival. Jass histopathologic classification predicted survival for patient group I and IV whereas no significant relationship was observed for group II and III, which, in our series, were the most frequently encountered groups. Of the three parameters considered for Jass classification, tubule configuration, pattern of tumor growth and lymphocytic infiltration, only the latter was significantly correlated to survival (p less than 0.005). Different results were obtained when the prognostic values of Jass group was investigated separately for the 49 patients with adenocarcinoma of the left colon and the 72 patients with rectal cancer. Further investigation is required before routine clinical application of the Jass classification can be recommended.

Adenocarcinoma↗