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Biomedical subjects

M Belvedere

Publications and source records attributed to M Belvedere.

At least 37 records · Page 2Linked to original sources
PubMed1981

An enzymatic method for microdetermination of aphidicolin: a promising anticancer drug.

We have developed a method, based on the in vitro inhibition of purified human DNA polymerase alpha, the major enzyme of DNA replication, which allows the rapid and accurate determination of pmol amounts of aphidicolin, a promising anticancer drug. The efficacy of this simple method was verified by the determination of aphidicolin in the liver, spleen, blood and urine of mice treated parenterically with the drug. Given its sensitivity and the avoidance of radioactive tracers, this enzymatic method is suitable for the determination of the drug in body fluids and tissue biopsies from living humans. It allows the detection and quantitation of aphidicolin in the presence of inactive metabolite(s) with very similar chemical structure(s) such as those generated by liver microsomal oxidases. The technique will also be useful to monitor the purification of the drug from cultures of Cephalosporium aphidicola.

Animals↗
PubMed1980

[Alkaline phosphatase isoenzymes and alpha-1-fetoprotein in hepatic neoplasms].

A study was made of possible relations between the placental alkaline phosphatase-isoenzyme (PAP), alpha 1-fetoprotein and liver neoplasia. Ninety-six with various liver diseases were examined, including 10 with primary and 16 with metastatic carcinoma. It was found that both PAP and AFP may be present in a certain percentage of subjects in this pathology. PAP (observed in 30% of cases of primary carcinoma and 43.6% of metastatic forms, as opposed to only 5.6% in cirrhotics) proved much more specific than AFP, which was present in both types of cancer (albeit at much lower concentrations) and also in acute, active chronic and persistent hepatitis, and in cirrhosis of the liver. The theories presented in the relevant literature are discussed in an attempt to explain the "reawakening" of both PAP and AFP, especially in liver neoplasias.

Alkaline Phosphatase↗
PubMed1980

Xenoantisera to DRw allospecificities.

The specificity of DR xenoantisera was assessed by testing them with a panel of HLA typed B-lymphocytes in a cytotoxic test with rabbit or human complement. The pattern of reactions of some xenoantisera correlated with DR allospecificities. These results confirm that injection of DR antigens across species barrier can elicit antibodies to DR allospecificities.

Animals↗
PubMed1980

Fab2 fragments from HLA xenoantisera specifically block cytolysis mediated by HLA-AB alloantisera.

Fab2 fragments from antisera raised in rabbits with partially purified cellular and serum HLA antigens were tested for their ability to block the cytolytic activity of operationally specific HLA-A,B alloantisera. One Fab2 fragment preparation blocked the cytolytic activity of all the HLA-A,B alloantisera tested; the remaining nine inhibited the lytic activity of alloantisera to certain HLA-A,B allospecificities, suggesting that these xenoantisera contain antibody to certain HLA-A,B allotype determinants or to closely associated structures. In contrast to previous reports in the literature none of the xenoantisera contained significant amounts of antibodies to human beta 2-microglobulin.

Animals↗
PubMed1980

Antibody-induced redistribution and shedding of membrane proteins in Duchenne muscular dystrophy lymphocytes.

Surface redistribution of molecules induced by specific antibody interaction was monitored by HLA antigen "lysostrip" experiments and "shedding" of Ig surface molecules, both in Duchenne Muscular Dystrophy patients and in normal controls. No significant difference in the rate of disappearance of the proteins for the lymphocyte surface was observed between patients and controls.

Animals↗
PubMed1979

Sera from volunteers immunized by planned blood transfusions as source of DR cytotoxic typing reagents.

Sera from volunteers immunized with planned blood transfusions were tested for anti DR cytotoxic antibodies with a panel of HLA typed cultured human lymphoid cells using a variety of serological techniques. The majority of sera contained DR cytotoxic antibodies. The specificity of DR antibodies in seven sera was determined by testing them with a panel of B peripheral lymphocytes typed with DR alloantisera submitted to the 7th International Histocompatibility Workshop. The temporal evolution of DR and HLA-A and B cytotoxic antibodies was determined in two subjects by testing serial bleedings with B lymphoid cells, coated with Fab2 fragments from anti beta 2 mu and anti DR xenoantisera. Results indicated a parallel evolution of DR and HLA-A and B cytotoxic antibodies.

Antibody Specificity↗
PubMed1978

Appearance and evolution of anti-Da (B cell-specific) antibodies after planned immunizations.

Appearance and evolution of anti-Da antibodies has been followed in eight volunteers immunized by whole blood transfusions or leukocyte intradermal injections form a single donor incompatible for HLA--A,--B,--C and--D specificities. Several unabsorbed bleedings from each recipient were studied against the specific immunizer with three different complement-dependent lymphocytotoxicity (CdL) techniques: (1) standard NIH CdL on total peripheral blood lymphocytes (PBL); (2) VII Workshop standard CdL technique on B cell-enriched suspensions; (3) beta2 microglobulin blanketing test ("bb" test) on B cells. Results obtained with the "bb" test were confirmed with platelet-absorbed sera. The "bb" and the absorbed sera allow discrimination between anti-Da and anti-HLA--A,--B,--C antibodies. Stage of appearance and evolution are rather similar for an anti-HLA--A,--B,--C and anti-Da. An early appearance of antibodies positive only against B cells is due to weak anti-HLA--A,--B antibodies which react better with B cells than with total PBL. Immunogenicity of Da antigens seems to be of the same order as HLA--A, and--B. In fact, Da reactivity was present in all eight recipients studied. These reactivities always segregated in familes with these HLA haplotypes. On a small panel of unrelated D-typed donors, three sera showed a significant positive association with D alleles.

Antibody Specificity↗
PubMed1978

Serologic and immunochemical characterization of HLA-A9 xenoantisera.

The specificity of A9 antiserum produced in rabbits immunized with high density lipoprotein-associated HLA-A9 from serum was investigated by using serologic and immunochemical approaches. After suitable absorption, the xenoantiserum No. 2958 is monospecific for A9 antigens in direct cytotoxic test. Data from lysostrip experiments and from blocking of cytotoxicity with Fab2 fragments indicate that the A9 xenoantiserum No. 2958 react with the same or closely associated antigenic structures recognized by A9 alloantisera. Immunoprecipitates obtained with the specific xenoantiserum No. 2958 and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis contained only proteins of the size of detergent-solubilized HLA and beta2-microglobulin (45,000 and 12,000 m.w.). Immunodepletion experiments indicated that the precipitation was mediated by antibodies directed to the heavy chain, and not the light chain of the complex. These results indicate that monospecific HLA-A9 xenoantisera have the same discriminatory capacity of alloantisera and can be useful for the serologic and immunochemical characterization of HLA antigens.

Absorption↗
PubMed1975

Antigenic determinants of the W28 molecule different from but spatially close to W28 determinant.

The existence of two allelic determinants, subtypic to W28 (named TO54 and TO55), and of an antibody cross-reacting W28 times HL-A10, is demonstrated. These new determinants have been studied by means of population and family studies and with the following serological techniques: absorption, elution, lysostrip and blocking by F(ab)-2 fragment. The results suggest that determinants TO54 and TO55 are very similar each other and are spatially close to the supertypic factor.

Adsorption↗