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Biomedical subjects

E Mihaesco

Publications and source records attributed to E Mihaesco.

50 records · Page 3Linked to original sources
PubMed1969

Immunochemical studies in four cases of alpha chain disease.

Studies of a number of properties of the pathological gammaA-proteins in the first four cases of the recently recognized alpha-chain disease demonstrate that, as in gamma-heavy-chain disease, the abnormal protein is devoid of light chains and represents a portion of the alpha-heavy chain related to the Fc-fragment. In two patients, serum electrophoresis showed a broad abnormal band, whereas in the two others the pathological protein was not noticeable on the electrophoretic pattern. The diagnosis of alpha-chain disease can be established without purification of the protein by immuno-electrophoresis and gel diffusion experiments using selected antisera to gammaA and a reference alpha-chain disease protein. All four proteins belonged to the alpha1-subclass, displayed electrophoretic heterogeneity, and showed a strong tendency to polymerize. The polymers occurred in vivo and were held together both by disulfide bonds and by strong noncovalent forces. Two of the three purified proteins had a very high carbohydrate content. The abnormal protein was always found in concentrated urines in variable but generally low amounts. It was not detected in parotid saliva but was present in significant amounts in jejunal fluid of all four patients. The alpha-chain disease protein was shown to be associated with the secretory piece in external secretions of two patients. The clinicopathological features were strikingly similar in the four patients. All patients were affected with a neoplastic and mostly plasmacytic proliferation involving primarily the whole length of the small intestine and the mesenteric nodes and all exhibited a severe malabsorption syndrome. While Israeli authors have emphasized the frequency of this type of abdominal lymphoma in young Arabs and non-Ashkenazi Jews, two of our patients were Kabyles, one a Syrian Arab, and one an Eurasian. Cellular studies showed that the pathological protein was synthesized by the proliferating cells in the lymphoid tissue of the digestive tract and in the mesenteric nodes, and that there was no detectable light-chain synthesis at the intracellular level.

Blood Protein Disorders↗
PubMed1968

Alpha-chain disease: a new immunoglobulin abnormality.

A new type of pathological immunoglobulin was found in the serum, urine, and saliva of a young Arab patient with abdominal lymphoma and diffuse lymphoplasmacytic infiltration of the small intestine. This protein is devoid of light chains and is closely related to the alpha polypeptide chains of the gamma(A1) (Le) subclass of immunoglobulin A. It is characterized by electrophoretic heterogeneity, tendency toward polymerization, and a high carbohydrate content. No intracellular synthesis of light chain was detected.

Arabia↗
PubMedDate not supplied

Immunochemical study of a human myeloma IgG1 half molecule.

The serum of a patient with multiple myeloma contained an IgG1 kappa monoclonal protein which existed in two molecular species: one with and one without inter-heavy chain covalent bonds, the latter dissociating into half molecules without reduction. The half molecules were present in the urine together with a kappa Bence-Jones protein. This peculiar protein was discovered because the serum and urinary IgG formed double percipitin lines when analysed by immunoelectrophoresis with an antiserum to gamma chains, the inner line being due to residual normal IgG. The isolated half molecule, as well as the major constituent of the 7 S IgG fraction, failed to precipitate with most antisera specific for the Fc fragment of IgG. The half molecule lacked the Gm(non a) marker and other antigenic determinants of the third constant region of gamma1 chains. No isotypic or allotypic antigenic determinant of another immunoglobulin class or subclass was detected. The molecular weights of the 7 S molecule, the half molecule and its covalently linked heavy and light chains were about normal, suggesting that they did not have a large deletion which could have caused the lack of interheavy chain covalent bonds. The hinge peptide appeared normal after high voltage electrophoresis of the peptic-tryptic digest of the reduced and alkylated half molecule. The carboxy-terminus of the heavy chain and the amino acid composition of the molecule were similar to those of IgG1 myeloma proteins. Two cysteinyl peptides of the CH3 domain showed on a diagonal peptidic map an electrophoretic mobility somewhat different from that of the corresponding peptides of an IgG1 myeloma protein. Another peculiar feature of this protein was the presence of galactosamine. Idiotypic determinants of the half molecule were present in the 7 S fraction, suggesting that the 7 S IgG molecules and the half molecules were derived from the same clone of tumour cells. Lack of material precluded further characterization of the structural abnormality--probably located in the third constant domain of the heavy chain--responsible for the absence of most antigenic determinants of the Fc region of IgG1 and for the formation of half molecules. This abnormality could be a small deletion undetectable by molecular weight measurements or an unidentified exchange of genetic material. Family members of the patient could not be studied in order to investigate whether this immunoglobulin abnormality reflected a minor genetic variant or a mutational event.

Amino Acid Sequence↗