PubMed Health⌕ Search

Biomedical subjects

S R Waschke

Publications and source records attributed to S R Waschke.

12 recordsLinked to original sources
PubMed1985

Decrease of HLA-DR antigen expression by human monocytes during cultivation in absence of exogenous or endogenous interferon-gamma.

The kinetics of HLA-DR antigen expression by human peripheral blood monocytes during cultivation in vitro was studied. Immediately after separation by glass adherence, about 60% of monocytes expressed DR antigens as judged by indirect fluorescence staining with a monoclonal antibody (BL-DR/1). Monocytes carefully depleted of lymphocytes, gradually lost their DR antigens during cultivation in the absence of exogenous interferon-gamma (IFN-gamma). However, addition of a few lymphocytes to the adherent cells prevented the decrease of DR antigen expression. Furthermore, it was shown that doses as low as 1 IU/ml of IFN-gamma are sufficient to induce DR antigen expression by cultured monocytes. Experiments with cyclosporin A suggest that lymphocytes contaminating the monocyte preparations can produce spontaneously sufficient amounts of IFN-gamma for maintenance of the DR antigens on monocytes.

Cells, Cultured↗
PubMed1985

Biphasic production of immune interferon during mitogen-induced blastogenesis of human peripheral blood mononuclear leukocytes.

Peripheral blood mononuclear leukocytes of 14 healthy blood donors stimulated by concanavalin A were shown to exhibit a biphasic pattern of the production kinetics of interferon. Maximum interferon titers were determined in the culture supernatants 8 and 48 h after addition of the mitogen. Both the early and late interferon production could be abolished by actinomycin D treatment of the induced cells implying that they depend on mitogen-stimulated de novo synthesis of cellular RNA. Under the conditions used the interferon mRNA was accumulated in treated cells during the first 4 h of incubation. The kinetics as well as the efficiency of concanavalin A-induced interferon production turned out to strictly depend on the nature of the protein source added to the culture medium. Only fetal calf serum and calf serum as compared to human albumin or pooled gamma globulin-free human plasma were found to give the highest interferon yields in true biphasic production pattern, thus explaining, at least in part, the differing data obtained by several investigators working with this particular interferon production system.

Concanavalin A↗
PubMed1983

Detection of interferon in the sera of patients with psoriasis, and its enhancement by PUVA treatment.

Interferon-like activity could be detected in the sera of nineteen psoriatic patients (interferon titres between 8 and 64 i.u./ml), whereas healthy controls were negative. Following PUVA treatment the interferon levels increased significantly (interferon titres between 32 and 128 i.u./ml). An enhanced interferon production could explain some of the immunological phenomena connected with PUVA treatment.

Adult↗
PubMed1981

The dsRNA motif in interferon induction.

A dynamic recognition process is proposed for the triggers of interferon induction. It might account not only for dsRNAs but also for a more general dsRNA-type recognition motif, created by various low-- and high-molecular-weight nucleic acid effectors.

Interferon Inducers↗
PubMed1979

Interferon induction in human lymphocytes by complexes of vinyl copolymers with polynucleotides.

Analogues of the dsRNA poly(I).poly(C), namely double-stranded like complexes of poly(I) or poly(C), respectively, with corresponding vinyl nucleobases copolymerized with various vinyl compounds are highly effective interferon inducers in human lymphocyte cultures. Like poly(I).poly(C) they stimulate the liberation of an inhibitor(s) of interferon activity and, moreover, display mitogenic effect. With respect to the extent of these effects the various inducers differ considerably.

DNA↗
PubMed1976

5-Formyl-2'-deoxyuridine: cytostatic and antiviral properties and possible modes of action.

5-Formyl-2'-deoxyuridine (fdUrd) was prepared by a new method starting from thymidine and investigated for its influence both on proliferation of cultured mammalian cells and virus replication in vitro. The compound was found to have strong cytostatic and antiviral properties: 50% inhibition of proliferation of BHK 21/C13 cells or Ehrlich ascites tumour cells (EAT) was obtained at 4 - 10(-6) and 6 - 10(-6) M, respectively, while the treatment of pseudorabies virus with the same concentration resulted in about 1.5 log reduction of virus yield. A concentration of 1 - 10(-4) M inhibited cell proliferation by 80 to 100% while the virus yield was reduced by more than 3 orders of magnitude. All inhibitions can be prevented by thymidine.--DNA synthesis of EAT cells in vitro, as estimated by incorporation of [32P]-phosphate or low concentrations of [3H]-thymidine, was inhibited. Further biochemical experiments have provided indirect evidence that the compound is phosphorylated by thymidine and thymidylate phosphorylating enzymes. An inhibition of cell free DNA synthesis was found to be depending on a given period of preincubation with the compound (supposed to be needed for the formation of fdUrd 5'-triphosphate). This suggests that the 5'-triphosphate of fdUrd is an inhibitor of DNA polymerases and--by analogy with experiments with 5-formyluridine-5'-triphosphate and RNA polymerases [14]--may be used as an affinity label for this group of enzymes. It is concluded that the described cytostatic and antiviral effects of fdUrd are due to an intracellular "lethal" synthesis of the relevant phosphates which inhibit thymidylate synthetase (as had been found earlier to occur with the chemically prepared nucleotide in cell free extracts [1, 2]) and DNA synthesizing enzymes.

Animals↗