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Biomedical subjects

D S Fair

Publications and source records attributed to D S Fair.

65 records · Page 4Linked to original sources
PubMed1979

Combined functional and immunochemical analysis of normal and abnormal human factor X.

Human Factor X was isolated from Cohn fraction III and characterized by polyacrylamide gel electrophoresis, amino acid composition, and isoelectric focusing. Two molecular forms with biological activity were observed at isoelectric points of 4.8 and 5.0. Antisera generated to Factor X was monospecific and used to establish an equilibrium competitive inhibition radioimmunoassay. This assay was specific for human Factor X and did not cross-react with human prothrombin or bovine Factor X within the sensitivity range of 6-300 ng Factor X antigen/ml. The mean concentration of Factor X based on the antigen was 11.9 mug/ml, whereas concentration values based on coagulant activity was 7.8 mug/ml. This 30% difference in measurement appears to result from the presence of a subpopulation of Factor X molecules devoid of coagulant activity. The radioimmunoassay was used to qualitatively and quantitatively compare purified Factor X to plasmic Factor X obtained from normal, warfarintreated, acquired Factor X-deficient, and congenitaldeficient patients. In all but one case, the Factor X present in these plasmas was immunochemically identical to the purified Factor X and permitted precise quantitation of these abnormal Factor X molecules. Factor X procoagulant activity was analyzed relative to Factor X antigen and the specific activities were used to characterize normal and abnormal Factor X molecules. Reduced Factor X activity in plasmas from warfarin-treated and acquired Factor X-deficient patients was attributed to both decreases in Factor X antigen and decreased function of the Factor X molecules. Congenitally deficient patients, in general, showed a reduction in Factor X antigen in parallel with Factor X procoagulant activities resulting from comparable decreases in specific biological activity of the molecules.

Amino Acids↗
PubMed1977

Circulating tumor cells in murine myeloma.

BALB/c mice bearing subcutaneous ADJ-PC5 myelomas had hematologic findings suggestive of a preleukemic syndrome: thrombocytopenia, anemia, leukocytosis, and megakaryocytic hyperplasia. Six BALB/c myelomas were successfully transplanted sc by fragments or cell suspensions of spleens from mice bearing a subcutaneous tumor, though typical myeloma cells were difficult to visualize by light microscopy in these spleens. The fidelity of transmission of the ADJ-PC5 myeloma by this procedure was shown by the retention of idiotypic specificity of the immunoglobulin produced by the tumor in a radioimmunoassay. The tumorigenic cell that homed to the spleen was apparent as early as 8 days after sc transplantation of the myeloma. The spleens of tumor-bearing mice, however, could destroy or suppress the expansion or growth of a limited number of cells that had migrated to the spleens. Tumorigenic cells present in the peripheral circulation constituted 2-3% of the leukocytes. These cells, however, had reduced levels of the murine myeloma viral and cell-associated antigens, were difficult to detect by an indirect immunofluorescence assay, and did not rapidly divide in this environment, as indicated by the very low number of cells detected by autoradiography.

Animals↗
PubMed1976

Antibody differentiation: apparent sequence identity between variable regions shared by IgA and IgG immunoglobulins.

We have analyzed a pair of human myeloma immunoglobulins (biclonal proteins) of the IgG and IgA classes from a single patient, GR. The light chains are identical in amino-acid sequence over 40 residues at their NH2-terminus, hwereas the heavy chains are identical throughout 45 residues of their NH2-terminus. Additional chemical and serological studies suggest the light chains and variable regions of the heavy chains (VH) are very similar, if not identical. The implications of these and of other published studies are discussed with regard to (i) the association of one VH region with multiple constant regions of the heavy chain (CH regions), (ii) two alternative types of V-C joining mechanisms, (iii) the differentiation of antibody-producing cells, and (iv) three categories of biclonal immunoglobulins.

Amino Acid Sequence↗
PubMed1976

Identification of multiple cytolytic components associated with the beta-LT class of lymphotoxins released by mitogen-activity human lymphocytes in vitro.

Cytotoxic activity (lymphotoxin (LT) associated with the 50,000 dalton beta-LT class of human lymphotoxins has been resolved into multiple components by chromatography on DEAE-cellulose or electrophoresis on polyacrylamide gels. The two components, termed beta-LT, and beta-LT2, are separable from the 90,000 m.w. alpha-LT, since neither component is neutralized by incubation with heterologous rabbit anti-alpha-LT antisera. However, the two components differ in their overall charge and relative heat stability with the betaLT1 component being more positively charged than the beat-LT2 molecule and extremely heat labile.

Cells, Cultured↗
PubMed1976

Development of monoclonal IgA and an apparent IgG in a patient with macroglobulinemia: sharing of individually specific antigenic determinants among IgM, IgA, and IgG.

Patient CM, who initially was diagnosed as having macroglobulinemia (IgM, kappa) was subsequently found to develop a monoclonal IgA(kappa) protein. Rabbit antisera directed against the patient's IgAm and IgM were rendered specific for individual antigenic (ind) determinants. The anti-IgAm and IgM ind sera reacted with both 131I labeled monoclonal proteins in a double antibody radioimmunoassay (RIA). In addition, both monoclonal immunoglobulins inhibited the reaction between labeled immunoglobulin and both ind antisera, and statistical analysis of the data suggested that the shared ind determinants were identical. The IgG fraction of patient CM's serum also contained a component which competed with both monoclonal IgA (CM) and IgM (CM) in the RIA specific for ind determinants. Analysis of serum samples taken over a 2-year period revealed that, in addition to IgM, both the IgA and IgG components possessing the shared ind determinant(s) were present in low concentrations in the earliest sample, although not detected by conventional techniques. The monoclonal IgA and the IgG component were found to increase in concentration over this time interval with a concomitant decrease in IgM. The regulation of immunoglobulin expression with respect to the proposed models of gene organization in antibody-producing cells was discussed.

Antibody-Producing Cells↗
PubMed1975

Studies on IgA and IgA monoclonal proteins derived from a single patient. Evidence for identical light chains and variable regions of the heavy chain.

Two immunoglobulins, IgA(K) and IgG(K), were isolated from the serum of a single patient with two monoclonal components (biclonal proteins). After chain separation, the light chains from each molecule were found to be identical by the following criteria: electrophoretic mobilities under various pH and dissociating conditions, amino acid compositon, fingerprint analysis of tryptic peptides and of 14C-succinylated chymotryptic peptides, and amino acid sequence of the N-terminal 40 residues. The heavy chains were indistinguishable for the N-terminal 45 amino acid residues. These data are consistent with the hypothesis that a single heavy chain variable (VH) region may be associated with two different heavy chain constant (CH) genes.

Amino Acid Sequence↗