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Biomedical subjects

H J Rapp

Publications and source records attributed to H J Rapp.

At least 163 records · Page 9Linked to original sources
PubMed1968

Synthesis of the first component of human complement in vitro.

Isolated segments of human colon and to a lesser extent ileum were capable of synthesizing hemolytically active C'1. This conclusion was based on the following evidence: After elimination of C'1 from tissue with EDTA, we found that segments of the intestinal tract in short-term organ culture showed a 50-1000-fold increase in C'1 activity. The rate of production of C'1 in human intestine was highly temperature dependent; C'1 production was reversibly inhibited by puromycin and actinomycin D. Furthermore, (14)C-labeled amino acids were incorporated into molecules which behaved like C'1. No significant C'1(hu) synthesis was observed in isolated segments of jejunum, stomach, liver, kidney, lung, spleen, lymph node, and thymus.

Amino Acids↗
PubMed1968

Heterogeneity of rabbit IgM antibody as detected by C'1a fixation.

The C'1a-fixing properties of purified rabbit IgM anti-benzenearsonate antibody were determined. When tested with sheep erythrocytes to which hapten had been coupled by diazo linkage, the number of C'1a molecules fixed was 21% of the number of IgM antibody molecules bound to the erythrocyte surface. This was not due to loss of C'1a-fixing capacity during the purification procedure. Preparative electrophoresis of the antibody concentrated C'1a-fixing molecules in the anodal region so that antibody fractions with greater C'1a-fixing capacity were obtained. The demonstration that C'1a fixation is a property of a subpopulation of IgM molecules provides evidence for previously unrecognized micro-chain heterogeneity.

Animals↗
PubMed1967

Efficiency of the first component of complement (C'1) in the hemolytic reaction.

With the use of the first component of guinea pig complement (C'1) labeled in vivo with (14)C-amino acids, we have obtained evidence that, under the conditions required for the assay of C'1, each molecule of C'1 capable of interaction with cell surface antigen-antibody complexes is capable of initiating the reaction sequence that leads to lysis of the cell.

Animals↗
PubMed1967

Mouse complement: the effect of sex hormones and castration on two of the late-acting components.

The titer of late-acting complement components in sera from male mice is 8-10 times higher than the titer of sera from female mice. Using assays developed to measure the serum content of two of the late-acting components, we have shown that this difference is due to the effect of androgen and estrogen on these two late-acting complement components. These two components have been tentatively identified as C'5 and C'6. Androgen and estrogen have greater effect on C'6 than on C'5. The possibility has not been excluded that still other of the late-acting complement components are affected by androgens and estrogens. The course of homograft rejection was unchanged in mice deficient in C'5 and C'6.

Animals↗