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Biomedical subjects

B Pau

Publications and source records attributed to B Pau.

120 records · Page 7Linked to original sources
PubMed1981

Immunotoxins: hybrid molecules of monoclonal antibodies and a toxin subunit specifically kill tumour cells.

Several attempts to attack tumours in experimental systems have been made using conjugates of chemotherapeutic agents or potent toxins with antibodies (immunotoxins). In vitro studies have been highly successful, showing target specificity of a high order in some cases. However, so far, such conjugates have been inadequate in vivo, probably for two main reasons. First, conventional heteroclonal antibodies are perhaps inappropriate, because purification by biochemical methods leaves a large amount of non-antibody gamma-globulins. The use of monoclonal antibodies may overcome this problem. Second, when whole toxins have been conjugated to antibodies there has been a strong residual nonspecific cytotoxicity due to the binding capacity of a subunit, the B-piece of the toxin. (Diphtheria toxin or ricin consist of two polypeptide subunits. The A-piece is responsible for inhibition of protein synthesis on ribosomes, and the B-piece binds to galactose residues on the cell membrane and facilitates the transmembrane passage of the A-piece.) In the present work the problem of nonspecific binding by the B-piece has been circumvented by using the A-piece only as the toxin component of immunotoxins; these immunotoxins are active both in vitro and in vivo.

Animals↗
PubMed1981

Monoclonal antibody against human renin.

By spleen cell fusion with NS1 myeloma, a mouse hybridoma was obtained which secretes an antibody directed against human renin. This monoclonal antibody recognizes human and monkey renin, but neither hog nor mouse. Preliminary experiments demonstrate the potential of this antibody for renin immunopurification and characterization.

Animals↗
PubMed1976

[Kinetics of Ca 2+ or Mg 2+ activated ATPase from lymphocyte plasma membranes].

The kinetic study of the C2+ ATPase activity of lymphocyte plasma memebranes allowed some properties of this enzyme to be evidenced. The Ca2+-activated hydrolysis of ATP is independent of a non-specific alkaline phosphatase. The substrate of the ATPase activity is the chelate Ca2+- ATP. Mg2+ may substitute for Ca2+ both as chelating ion and as activating ion. Several results suggest that we have only one ATPase, activated either by Ca2+-, or by Mg2+ with less efficiency; both chelates hve the same Km; pH values for maximum activity and transition temperatures are identical; the effects of free ions are also the same, activation at low concentration and inhibition at high concentration.

Adenosine Triphosphatases↗
PubMedDate not supplied

Levels of myosin heavy chain fragment in patients with tissue damage.

BACKGROUND: Myosin heavy chain fragments (MHC) levels are observed to be higher in myoskeletal injuries after surgery. MHC could be a helpful supplementary tool in the study of myoskeletal injuries. METHODS: Serum levels of myosin heavy chain fragments (MHC) were assessed in orthopedic patients before operation (OBO) and after operative (OAO) repairs and in the early phase of soft tissue injury (STI) using a radioimmunoassay involving monoclonal antibodies to the human beta-type MHC. RESULTS: Mean (SD) microU/L of MHC in comparison with the control subjects (75.3 +/- 47.1) was higher in OAO (305.8 +/- 38.1) p <0.0001, and no significant changes in MHC were found in STI (67 +/- 77.5). Myoglobin was notably higher in OBO (81.9 +/- 95.0) compared to STI (43.9 +/- 55.9) or controls p <0.05, but there was no further change in the protein after surgery. The mean proportional raised level of myoglobin in OBO was >twofold, and MHC increased by 27%. Neither myoglobin nor MHC increased in the plasma of the STI within 24 h of injury. CONCLUSIONS: These data suggest that the release of MHC could be a helpful supplementary tool in the study of tissue damage in humans.

Antibodies, Monoclonal↗
PubMedDate not supplied

Production and partial characterization of anti-Candida monoclonal antibodies.

Spleen cells of Biozzi HR mice immunized with formolized, lyophilized Candida albicans serotype A cells were fused with P3-X63-Ag8.653 mouse myeloma cells. Twenty-one monoclonal antibodies (mAb) selected by an indirect ELISA technique were produced and partially characterized. All mAb reacted with a C. albicans cell wall extract. Five of the mAb were directed against C. albicans serotype A, but not against serotype B. These mAb also recognized C. tropicalis. The 16 other mAb cross-reacted with several yeast species. The immunoreactivity profiles of 5 representative anti-Candida mAb were confirmed in most cases by inhibition studies.

Animals↗
PubMedDate not supplied

Comparison of different immunoenzymatic methods for the determination of the fine specificity and affinity constants of polyclonal antibodies against pseudopeptide haptens.

We evaluated two phosphinopeptides and one phosphonopeptide, which are transition state analogs of a proteolytic reaction, for their ability to generate murine polyclonal antibodies. The specificity of these antisera was determined by indirect and competitive ELISA. Cross-reactivity analysis by these ELISA showed that the antisera recognized selectively haptens containing a phosphate group. The pseudopeptides recognized by the antisera in the indirect ELISA were not the same, however, as those recognized in the competitive ELISA. The differences between these results are probably due to the presentation forms of the hapten, i.e., passively adsorbed in the former ELISA format and soluble in the latter. The affinity of the antibodies was then determined by using two methods based on competitive ELISA, one described by Friguet et al. and the other by Seligman. The dissociation constant (Kd) values calculated by the two methods, for an antiserum and its homologous hapten, are similar. However, only the middle portion of the inhibition scale in Seligman's method gave access to reliable values. Nevertheless, the Seligman representation allowed us to underscore the large range of affinity constants of the polyclonal antibodies.

Animals↗
PubMedDate not supplied

Improved performances of spot multiple peptide synthesis.

We have developed a new software for the design of peptides to be prepared by the manual Spot synthesis method. It covers most of the common protocols for epitope mapping and offers flexibility for planning the experiment. We have also quantified the coupling efficiencies of three different coupling methods for the synthesis of four model decapeptides. The DIC/HOBT procedure was superior (mean coupling yield per cycle: 87% to 91%) to methods using pentafluorophenyl esters of Fmoc amino acids. All four peptides prepared by the three different coupling protocols were reactive with their cognate monoclonal antibody. Finally, using the best coupling method, we synthesized peptides of increasing length (10 to 29 residues) bearing the model epitope AcPGK at the N terminus and showed that peptides of up to 29 residues were immunoreactive.

Antibodies, Monoclonal↗
PubMedDate not supplied

Cardiac troponin I in patients with hematologic malignancies.

BACKGROUND: The cardiac isoform of troponin I (cTnI) is a myofibrillar protein highly specific for myocardial injury. We used a recently developed new-generation immunoassay with high analytical sensitivity to measure cTnI in patients diagnosed with hematologic malignancies, before chemotherapy and after an intermediate cumulative dose of anthracyclines. We hypothesized that measurement of cTnI with this sensitive method would provide evidence of myocardial injury in these patients. METHODS: Sera from 115 individuals (60 healthy controls, 25 anthracycline-naive patients and 30 patients treated with intermediate cumulative doses of anthracyclines) were assessed for cTnI, creatine kinase MB (CKMB) mass and myoglobin. Radionuclide left ventricular ejection fraction (LVEF) was also determined. RESULTS: Using this sensitive assay, detectable concentrations of cTnl were measured in the healthy population [mean, 19.5 pg/ml, 95% confidence interval (CI) 13.5-25.5 pg/ml]. Anthracycline-naive patients had cTnI mean values (36.5 pg/ml, 95% CI 25.1-47.9 pg/ml) that were significantly (P < 0.01) greater than those in the control group. cTnI was significantly (P < 0.00001) increased in anthracycline-treated patients (76.4 pg/ml, 95% CI 67.0-85.8 pg/ml) compared with both the anthracycline-naive patients and the controls. CKMB, myoglobin and LVEF were within the normal range in all patients. CONCLUSIONS: These data provide evidence for cardiac involvement in patients with hematological malignancies before and during the course of anthracycline chemotherapy. They suggest that detection of myocardial injury may be facilitated by measurement of cTnI with a highly sensitive assay.

Adult↗