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Biomedical subjects

R Johannsen

Publications and source records attributed to R Johannsen.

35 records · Page 2Linked to original sources
PubMed1978

Evidence for subtypic determinants in the HLA-DW3 cluster.

This study was undertaken to get more insight into the previously suggested heterogeneity of the HLA--DW3 cluster. Preliminary evidence of DW3 heterogeneity was derived from results of intrafamilial mixed lymphocyte culture tests (MLC) where cells of apparently homozygous offspring revealed unexpected stimulations of one of the parents' cells. Therefore, 15 different homozygous typing cells (HTCs) of DW3 specificity were tested against 43 HLA-DW3 heterozygous individuals. The response patterns of the 43 HLA-DW3 heterozygous cells toward 13 HTCs leads to the definition of at least three groups of DW3 stimulating cells. According to these patterns, four groups of responding cells could be classified. These results were confirmed by a MLC checkerboard experiment running all DW3-HTCs against each other. Discussing all possible explanations for these observations, the authors conclude that the existence of DW3 subtypes having some properties in common is the most likely interpretation of the results obtained. Family segregation studies will be needed to define the genotypic situation of the DW3 cluster.

Antibody Specificity↗
PubMed1977

Population data on two new HLA-D determinants, EI and RE.

Homozygous typing cells (HTC) for two new HLA-D determinants, EI and RE, defined by family studies, are described. The HLA-D typing experiments among more than 300 unrelated individuals showed phenotype frequencies of 0.045 for EI and 0.098 for RE. Since the tested population was also typed for its HLA-A and -B alleles, linkage disequilibrium parameters could be calculated: HLA-D type EI was statistically significantly associated with HLA-B13 and Bw17, HLA-D type RE with HLA-Bw40. These data support the working hypothesis that both EI and RE are new alleles of the HLA-D series.

Alleles↗
PubMed1975

[Immunologic aspects to the prevention of infection cardiac surgery (author's transl)].

1. The humoral immunosystem is impaired in those cases of catabolic metabolism in which quantitative and qualitative insufficient alimentation is expected after operation. 2. We showed that after cardiac surgery with extracorporal circulation as well as after other operations a reasonably balanced parenteral nutrition composed of carbohydrates and amino acids could considerably inhibit the changes in the humoral immunity, which is a valuable contribution to the prevention of infection. 3. In our experiments on transformation of lymphocytes after mitogenic stimulation, the depressive effects of operation on the cellular immunity were found to be etiologically more complex than was previously assumed in publications.

Bronchoscopy↗
PubMed1975

Membrane associated antigens of human malignant melanoma. I. Internal labeling, detergent solubilization and characterization by homologous antisera and polyacrylamide gel electrophoresis.

Cultured melanoma cells were labeled with 3H-leucine over a period of 1-3 days. The labeled cells were mechanically disrupted and a preparation of "extranuclear membranes" was obtained by differential centrifugation. The membrane fragments were solubilized by the nonionic detergent NP-40 and the soluble material was double precipitated with antisera from melanoma patients and anti-human immunoglobulin sera. Because of the small quantitative differences of precipitated radiolabeled material between control and melanoma patients' sera, the precipitates were further analyzed on SDS-containing polyacrylamide gels. The labeled profiles of experimental and control gels now revealed clearcut differences usually seen in 2-3 characteristic peaks in the molecular weight range from 130,000-330,000.

Antigens, Neoplasm↗
PubMed1975

[Immunosuppressive effects of operations and their possible limitation (author's transl)].

1. The humoral immunosystem is impaired in those cases of catabolic metabolism in which quantitative and qualitative insufficient alimentation is expected after operation. 2. After cholecystectomies as well as after cardiac surgery with extracorporal circulation a reasonably balanced parenteral nutrition composed of carbohydrates and amino acids would considerably inhibit the changes in the humoral immunity, which is a valuable contribution to the prevention of infection. 3. In our experiments on transformation of lymphocytes after mitogenic stimulation, the depressive effects of operation of the cellular immunity were found to be etiologically more complex than was previously assumed in publications.

Amino Acids↗
PubMed1970

Complement and complement-like activity in lower vertebrates and invertebrates.

A purified cobra venom factor with C-inhibiting activity also promotes lysis of erythrocytes in fresh mammalian serum. Lysis-inducing activity of purified cobra venom factor was found in sera of lower vertebrates including the cyclostome hagfish and in invertebrates. Lysis-inducing activity was most effective with frog serum. Frog serum was found to be more hemolytic for E(s) in the presence of CVF than when cells were sensitized with hemolysin. The hemolysis induced by CVF with frog serum, as in the higher vertebrates, was inhibited when sera were pretreated with known C inhibitors including heat, chelators, endotoxin, immune complexes, and CVF itself. Complexes formed with CVF and either frog serum or invertebrate hemolymph promoted lysis of indicator cells in the presence of frog serum in EDTA. This lysis was most marked when the starfish-CVF complex was used and was C-dependent. Conversely, complex formed with frog serum and CVF promoted lysis of E in the presence of invertebrate hemolymph (Limulus) in EDTA. Hence, serum components were to some degree at least interchangeable between vertebrate sera and invertebrate hemolymph. Lysis-inducing activity of purified CVF occurs in a wide range of species, has revealed activities resembling those of terminal C-components in lower vertebrates and invertebrates, and provides one means for study of C and C-like activities in primitive species.

Amphibians↗