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Biomedical subjects

R Masseyeff

Publications and source records attributed to R Masseyeff.

At least 55 records · Page 3Linked to original sources
PubMed1980

[Enzymo-immunologic determination of the class of antiglobulin factors].

The authors describe an enzymo-immunologic method of determination of the class of rheumatoid factors (RF). This technic includes 3 main stages : 1) extraction of RF by fixation on aggregated rabbit IgG previously adsorbed on the walls of a plastic tube; 2) recognition of RF linked to the solid phase by anti-IgG addition, and addition of human IgA and IgM linked to glucose oxidase; 3) revelation of the enzyme activity linked to the solid phase : this enzyme activity directly depends on the levels of RF to be estimated. The results are expressed as a percentage of the fixation of a reference serum obtained from a patient with rheumatoid arthritis (RA). This serum presents an antiglobulin activity in the 3 major classes of immunoglobulins. The coefficients of variation of intra- and intersystem reproductibility lay between 5,6 and 17.8%. The specificity of the estimation was controlled by the localisation of the antiglobulin activity of the sera after chromatography on Sephadex G200 and by estimation of RF after their absorption by an aggregated IgG immunoadsorbant. This technic was applied to the identification of RF in RA (90 cases); in diseases not related to RA and in control subjects : the sensitivity of this method appears greater than that of technics previously described (immuno-fluorescence, Rose-Waaler reaction) in fact, only 12,2% of sera of patients with RA remain negative with this new test. However, this greater sensitivity does not seem to have altered the clinical specificity of the test : in fact, only 8,4% of the sera of patients with diseases unrelated to RA are positive by this method, which, moreover, may be explained by the age of these subjects (average age 71.5 years).

Aged↗
PubMed1979

Coupling of gamma-globulin to microcrytstalline cellulose by periodate oxidation.

Anti-rabbit IgG sheep gamma-globulins were covalently coupled to periodate oxidized microcrystalline cellulose using the Schiff reaction. Optimal conditions (sodium m-periodate concentration and gamma-globulin amount) were studied measuring the ability of this solid-phase antibody to bind glucose oxidase-labeled rabbit IgG.

Animals↗
PubMed1979

Purification and characterization of an estrogen-binding peroxidase from human fetuses.

A peroxidase found under two forms with a molecular weight of 220,000 and 170,000 respectively, was purified from human fetuses. The purification procedure included ammonium sulfate precipitation, ion exchange chromatography, gel filtration and hydrophobic interaction chromatography. The purification factor approximated 400. These two forms of peroxidase were found to be immunologically identical as shown when utilizing immunodiffusion. They were able to bind estradiol in the presence of H2O2. This bond resisted to denaturation and solvent extraction therefore suggesting a covalent binding of estradiol to the enzyme.

Carrier Proteins↗
PubMed1979

Non-excretory multiple myeloma.

The clinical and laboratory features in five patients with non-excretory myeloma are described including plasma cell immunofluorescence and, in two cases, ultrastructure. Findings are compared with those in similar patients previously reported, and those in excretory disease. Clinical, haematological and biochemical features were similar to those found in excretory myeloma, showing differences only in relation to the absence of serum or urinary monoclonal immunoglobin. Cellular cytological and ultrastructural features allowed no differentiation from excretory cells. Within this non-excretory group distinction between secretory and non-secretory myeloma cells is possible on the basis of immunofluorescence. Differing patterns of intermittent excretion occurred in three of these patients.

Aged↗
PubMed1979

Conjugation of glucose oxidase from Aspergillus niger and rabbit antibodies using N-hydroxysuccinimide ester of N-(4-carboxycyclohexylmethyl)-maleimide.

Glucose oxidase from Aspergillus niger was conjugated with rabbit immunoglobulin G or its monovalent fragments (Fab'). The enzyme was treated with N-hydroxysuccinimide ester of N-(4-carboxycyclohexylmethyl)-maleimide to introduce maleimide groups, which were then allowed to react with thiol groups of reduced IgG or Fab'. More than 40% of immunoglobulin G, Fab' and enzyme used could be conjugated without self-coupling. The enzyme activity decreased about 26 and 15% upon conjugation with immunoglobulin G and Fab', respectively, and the ability of antibody to bind to antigen was well preserved in conjugates. Conjugate preparations purified by gel filtration contained little free form of immunoglobulin G, Fab' or enzyme. Both the cross-link and enzyme activity in Fab' conjugate were stable at pH 6-7 at 4 degrees C for at least 6 months.

Animals↗
PubMed1978

[Enzymo-immunological estimations. Principles and applications (author's transl)].

Diagrams of the reactions of enzymo-immunological estimations are similar to those of radio-immunoassay. The only difference is that an enzymatic label is substituted on the antigen or the antibody for the isotopic label and that consequently a measurement of enzyme activity replaces isotopic counting. One must therefore add a further stage of substrate addition and a stage of enzyme reaction. There is however a technic which has no equivalent in radio-immunoassay, the EMIT system, where one measures the change in activity of a haptenised enzyme under the influence of the corresponding anti-haptene antibody. The author reviews the main problems raised by the first group of technics and gives a few examples of the results of estimation of alpha-foeto-protein obtained with 3 different reactions with fairly similar performances. The advantages and disadvantages of enzymo-immunologic technics are reviewed. The two major advantages seem to be the stability of the reagents and the fact that they avoid the administrative controls which restrict the use of isotopes.

Antibodies↗
PubMed1976

Study of two cases of bisalbuminemia by electrofocusing.

Isoelectric focusing was used to compare normal seric albumin and seric albumin from two subjects with bisalbuminemia. An additional new albumin fraction was found in each of these two anormal sera. The isoelectric point of these variants was respectively 5.65 and 5.84. These results suggest that isoelectric focusing may be used to identify and classify the different variants of albumin.

Blood Protein Disorders↗
PubMed1976

Alpha-foetoprotein and oestrogen metabolism. I. -Influence of alpha-foetoprotein on the metabolism of steroids by rat liver microsomes in vitro.

Rat alpha-foetoprotein (AFP) was shown to inhibit the formation of water soluble metabolities of oestrone and oestradiol by incubation with microsomes from rat liver in the presence of NADPH. The results support the proposal that in young animals the low activity of enzymes responsible of oestradiol metabolism may be due in part to the presence of AFP and not only to the low level of these enzymes.

Age Factors↗