PubMed Health⌕ Search

Biomedical subjects

R Heimer

Publications and source records attributed to R Heimer.

At least 73 records · Page 4Linked to original sources

Suppressor cell dysfunction and necrotizing lesions in a child.

A girl had opportunistic infections and was found to have T-cell dysfunction. During a period of months, recurrent staphylococcal infections, polyclonal hyperglobulinemia, eosinophilia, and peripheral, necrotizing, cutaneous lesions developed. Circulating immune complexes were demonstrated, and abnormal suppressor-cell function was found. At age 36 months, the child died of a staphylococcal pneumonia. At postmortem examination, the thymus gland was found to be histologically abnormal, lacking corticomedullary differentiation. We propose that this patient had a syndrome in which lymphocyte abnormalities and dysfunction of suppressor T cells permitted hyperresponsiveness of antibody-forming cells. Large amounts of circulating antibody and immune complexes were formed, and their deposition led to peripheral tissue injury.

Antigen-Antibody Complex↗

Enhanced 5-fluorouracil nucleotide formation after methotrexate administration: explanation for drug synergism.

Exposure of L1210 leukemia cells first to 0.1 to 100 micromolar methotrexate and then to 10 micromolar 5-fluorouracil produces a synergistic effect on the number of cells killed in culture. Methotrexate dose-related increases occur in the concentrations of intracellular 5-fluorouracil ribonucleotides and 5-fluoro-2'-deoxyuridylate and in the incorporation of 5-fluorouracil into RNA. These increases are correlated with increased concentrations of intracellular phosphoribosylpyrophosphate. It is proposed that the enhanced formation of ribonucleotides of 5-fluorouracil and the subsequent incorporation of these compounds into RNA in methotrexate-treated cells may account for synergism between these agents.

Animals↗

The examination of antigens in highly purified immune complexes.

A combination of gel filtration and affinity chromatography was used for preparation of immune complexes (IC) from sera of individuals with systemic lupus erythematosus (SLE) and others with no apparent disease. Overlaying of gels with patient or normal sera, counterstaining with 125I-protein A and autoradiography showed besides immunoglobulins, the presence of 6 unidentified antigens with molecular weights below 42,000 dalton. They were not exclusively associated with SLE IC.

Animals↗

Circulating immune complexes in sera of hamsters bearing simian virus 40-induced tumours.

Reported previously in certain human carcinomas and rat and mouse experimental tumor systems, circulating immune complexes (IC) have now been detected in Syrian hamsters bearing tumors produced by injection with syngeneic TSV5Cl2 cells. IC were detected by the Raji cell radioimmune assay, adapted for use in hamster sera. A novel feature of this test is the use of a stable covalently linked hamster immunoglobulin G aggregate as the reaction standard. Stable over six months on storage at -70 degrees and showing no tendency to form precipitates on thawing or during test procedures, this preparation greatly facilitated quantitation of hamster IC by Raji cells. Seven of 19 sera of hamsters bearing SV40-induced tumors from 60 to 128 days had IC concentrations exceeding 40 microgram aggregated hamster immunoglobulin G equivalents per ml, as contrasted to IC levels of less than 25 microgram for 19 age-matched normal hamsters. There appeared to be no significant correlation between IC levels and tumor weight or duration of tumor within the hamster host. The results suggest a complex relationship between IC and a number of factors connected with tumor growth.

Animals↗

The affinity of soluble immune complexes for concanavalin A.

Con A-Sepharose affinity chromatography may be used in the analysis and classification of immune complexes. Experiments with model immune complexes suggest that the degree of affinity of an immune complex for Con A-Sepharose is determined by the antigen rather than the IgG antibody of the complex. It is possible that partial characterization of unknown antigens linked to IgG in immune complexes may be achieved in many diseases. Preliminary explorations with selected human sera indicate that the IgG containing immune complexes in Burkitt's lymphoma and nasopharyngeal carcinoma have affinity for Con A-Sepharose. By contrast IgG containing immune complexes in chronic hepatitis B seem to lack affinity for Con A-Sepharose.

Antigen-Antibody Complex↗

Circulating immune complexes in sera of patients with Burkett's lymphoma and nasopharyngeal carcinoma.

Sera of individuals with Burkitt's lymphoma and nasopharyngeal carcinoma, tested by consumption of hemolytic complement, were found by comparison with healthy individuals to have significantly increased levels of circulating immune complexes. The identity of the immune complexes was established by sucrose density gradient ultracentrifugation, which showed them to sediment between 10 and 19S. As they were adsorbable by rheumatoid factor--Sepharose 4B conjugates, it appeared that these complexes were composed of IgG. The complexes were retained by Concanavalin A--Sepharose columns and eluted by alpha methyl-D-mannoside, suggesting by analogy with model complexes that the antigens might be glycoproteins.

Adsorption↗