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Biomedical subjects

C Rosenfeld

Publications and source records attributed to C Rosenfeld.

At least 55 records · Page 3Linked to original sources
PubMed1988

Elevated platelet-surface-bound IgM in thrombotic thrombocytopenic purpura.

The level of platelet-surface-bound IgM (PSIgM) was measured during the course of therapy in two patients with thrombotic thrombocytopenic purpura (TTP). Before therapy, both had significantly elevated PSIgM. In both cases the PSIgM dropped after the institution of treatment with plasmapheresis, steroids, and dipyridamole, correlating with a complete response to therapy in one patient and a partial response in the second. This is further evidence that in some cases of TTP, an immune mechanism is present.

Adult↗
PubMed1987

Platelet satellitism: a possible mechanism.

Markedly increased platelet surface-bound IgG was found on platelets collected in citrate and heparin in a patient with platelet satellitism. The level on platelets collected in EDTA was mildly increased. However, neutrophils from this patient collected in EDTA had markedly increased surface IgG due to attached platelets, while no surface IgG was seen in citrate or heparin neutrophils, indicating that the anticoagulant EDTA in some way modified the surface IgG or neutrophil membrane resulting in platelet attachment. This is the first case in which a possible mechanism for platelet satellitism has been identified.

Blood Platelets↗
PubMed1986

Screening monoclonal antibodies against cell-surface antigens. High frequency of natural antibodies.

Two commonly used methods for screening hybridoma supernatants against cell-surface antigens were performed simultaneously on the supernatant culture fluids of different hybridizations, and compared with the detection of Ig secretion. Supernatants reacting with glutaraldehyde-fixed cells (ELISA (Enzyme-linked immunosorbent assay) on fixed cells) are mostly non-specific for the immunogen; in addition, with this method, only half of the antibodies detected by immunofluorescence are identified. These results can be explained by the frequent occurrence of hybridomas secreting antibodies displaying 'natural antibody' properties, which are strongly reactive with intracellular antigens, and apparently made accessible by the fixation procedure. Since artefacts impair the interpretation of results with ELISA on fixed cells, and complement-mediated cytotoxicity usually as a low yield, membrane immunofluorescence remains the best method for screening hybridoma antibodies.

Animals↗
PubMed1985

Decay B--> psi X.

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Journal Article↗
PubMed1985

Protein kinases in human leukemic cells.

Protein kinase activities and cyclic AMP binding capacity were investigated in human peripheral blood cells from leukemic patients and normal controls. Using [gamma 32P] ATP as phosphoryldonor, the phosphorylating activities were not found to be significantly different in either normal or leukemic cells when measured on both artificial basic and acidic substrates. In contrast, the GTP-dependent casein kinase activity, CK2, which is almost undetectable in normal granulocytes, was markedly increased in highly proliferating myeloblastic cells from patients with acute myelogenous leukemia (AML) or with chronic myelogenous leukemia in blastic crisis (BC-CML). Levels of endogenous phosphotyrosine were not higher in leukemic cells than in normal peripheral lymphocytes or granulocytes. Finally, cAMP binding capacity was found to be increased in several types of proliferating leukemic cells, due to a higher amount of the R1-type regulatory subunit of the cAMP-dependent protein kinases. Specific patterns of cAMP binding proteins observed in the different types of normal blood cells were rather blurred in leukemic cells. In conclusion, modifications observed in human leukemic cells seem to be more related to proliferation or blockage in normal differentiation than to their cellular origin.

Adenosine↗