Search PubMed⌕ Search

Biomedical subjects

R D Karp

Publications and source records attributed to R D Karp.

28 records · Page 2Linked to original sources
PubMed1977

Micro mixed hemadsorption assay--a sensitive method for detecting antibodies against tumor-associated antigens.

Antibodies against methylcholanthrene (MCA)-induced sarcomas in Fischer (F344) rats were detected by a modified micro mixed hemadsorption (MHA)-assay. The assays detected anti-tumor antibodies as titers up to 1 : 320 in sera from hyperimmunized rats and at titers up to 1 : 160 in sera from rats bearing a 5-8 cm3 progressively growing tumor. MHA-titers decreased when sera were absorbed with sarcoma cells prior to MHA-assays. IgG antibodies in sera from tumor bearing rats showed titers of 1:20 and 1:5. These anti-tumor sera formed rosettes on the corresponding sarcoma cells as well as other sarcomes induced by MCA in F344 and Lewis strain rats tested. The assay was modified for a micro technique using a microtest plate (No. 3034, Falcon, CA). This modification yielded as assay requiring only 10 microliter of test sera. The test is quantitative and highly sensitive and results are reproducible. Several critical factors which influence test results in this assay were examined.

Animals↗
PubMed1976

Specific allograft reactivity in the sea star Dermasterias imbricata.

Transplantation studies with the sea star Dermasterias imbricata revealed that this echinoderm rejected most first-set allografts after prolonged chronic reactions. All control autografts remained intact and fully viable. The greatly accelerated rejection of subsequent second- and third-set allografts demonstrated that these reactions were not only highly specific, but that these animals possess at least short-term immunological memory. The specific nature of the allograft response was confirmed by the prolonged survival of unrelated third party allografts placed at the same time as second- or third-set allografts. Animals in these experiments were maintained in sea water at temperatures of 14-16 C. Since this low temperature is required for successful maintenance of this species, temperature-dependence studies could not be undertaken. The rejection reaction was characterized by loss of pigmentation, edematous swelling, and necrosis. Histologically, the allograft tissue was heavily infiltrated by lymphocyte-like cells and phagocytic cells, causing disruption of the normal cytoarchitecture of the dermis. Deposits of fibrous material were also in evidence. Autografts, on the other hand, remained fully viable with no signs of rejection. We conclude that this asteroid, a representative of the echinoderms, has a well-developed, cell-mediated immune response analogous to that of vertebrates.

Animals↗
PubMed1968

Effect of immunosuppressive agents on normal phage-neutralizing antibody in the mouse.

The actions of three immunosuppressive drugs on normal antibody synthesis in the adult mouse were determined. Inbred mice were given daily intraperitoneal injections of actinomycin D, uracil mustard, or cyclophosphamide for extended periods. The sera of treated and untreated mice were assayed for phage-neutralizing activity to monitor the effect of each drug on the amount of circulating normal antibody. Except for an initial decrease in titer of normal anti-phage MSP2 activity, actinomycin D had no significant effect on normal antibody activity. Uracil mustard caused alternating elevation and depression of normal antibody titers. Cyclophosphamide caused a prolonged depression of normal antibody. The response patterns to the three immunosuppressive agents were the same for both induced and normal antibody.

Animals↗
PubMedDate not supplied

Transplantation immunity in the American cockroach, Periplaneta americana: the rejection of integumentary grafts from Blatta orientalis.

The results from several previous studies have indicated that the American cockroach is able to respond to integumentary xenografts, but doubt remained as to whether cockroaches could effectively discriminate between self and allogeneic differences. This was emphasized by the fact that while one study reported that Periplaneta americana responded to grafts donated by the closely related genus Blatta orientalis, the data reported elsewhere, using a different assay system, found no such reactivity. Since we have subsequently reported, using a direct histological assay, that Periplaneta can in fact recognize and destroy integumentary allografts, we initiated a study to hopefully sort out the enigma presented by previous data using Blatta as a transplant donor. Integument from Blatta orientalis was transplanted orthotopically onto Periplaneta americana, and at various time points post-transplant, scored histologically for the survival of the subcuticular epidermal layer. The results clearly demonstrated that Periplaneta reacted to the Blatta tissue, because approximately 82% of the grafts had the epidermal layer destroyed by day 7 posttransplant. The kinetics of the response to Blatta was more in line with our allograft data, which would be in agreement with other work indicating that the closer the donor and recipient are on the phylogenetic tree, the less intense the reactivity to the foreign transplant.

Animals↗