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Biomedical subjects

E Wiener

Publications and source records attributed to E Wiener.

At least 73 records · Page 4Linked to original sources
PubMed1986

Elution of antispectrin antibodies from red cells in homozygous beta-thalassaemia.

It is well-established that autoantibodies against red cell membrane antigens, such as spectrin are present in plasma of humans and animals. It is shown here that antispectrin IgG antibodies can be eluted from the red cells of patients with beta-thalassaemia intermedia. It is suggested that these antibodies could play a part in the increased rate of destruction of red cells in homozygous beta-thalassemia, either by reacting with spectrin which is abnormally exposed on the red cell surface or by a cross-reaction with a different membrane component. No rise was found in serum antispectrin levels in beta-thalassaemia; anti-red cell membrane IgG levels were slightly raised, but there was considerable overlap between the levels in patients and in normals. No autoantibody could be found in eluates from cells of normal subjects or patients with sickle cell anaemia.

Adolescent↗
PubMed1985

Internalization of metallochromic Ca2+ indicators in mammalian cells.

Two new techniques for internalizing metallochromic indicators into the cytosol of mammalian cells are described. One method consists of hypertonically treating the cells in the presence of the indicator, followed by a hypoosmotic treatment. The second method consists of incubating the cells at high density in a concentrated indicator solution in physiological saline. Using either method, arsenazo III or antipyrylazo III was internalized into Ehrlich Ascites tumor (EAT) cells at concentrations yielding measurable differential absorbance changes which correspond to changes in the intracellular Ca2+ concentration. In the case of antipyrylazo III, the amount of indicator internalized ranged between 140 and 350 microM, and was dependent on the metabolic state of the cell during loading. Control and loaded cells possessed virtually identical ATP/ADP ratios, as measured by high performance liquid chromatography (HPLC) in cell extracts. Antipyrylazo III was also internalized by rat hepatocytes without detectable cell damage. Treatment of metabolically active EAT cells with the calcium ionophore A23187 results in only a slight increase in the intracellular free Ca2+ concentration, [Ca2+]i, whereas treatment with the calcium ionophore ionomycin induces a substantial but transient increase in the [Ca2+]i. In contrast, metabolically inhibited EAT cells show a large rise in the [Ca2+]i upon addition of A23187. Thus, these techniques offer another way of measuring intracellular free Ca2+ changes in mammalian cells and may prove useful, especially where concentrations of free cytosolic Ca2+ larger than 1 microM are expected.

Adenine Nucleotides↗
PubMed1985

A possible role for antibodies against spectrin in the interaction between erythroblasts and macrophages in vitro.

The nature of serum factors which participate in the interaction in vitro between dimethylsulphoxide-induced Friend leukaemia erythroblasts (IFLE) and syngeneic mouse peritoneal macrophages was investigated. When heat-inactivated newborn calf serum (HI-NBCS) was depleted of IgG its activity to promote the association of neuraminidase-treated 59Fe-labelled IFLE (59Fe-IFLE) with macrophages was markedly reduced but could be restored by the addition of bovine IgG. Trypsin treatment of macrophages caused incomplete inhibition of their subsequent association with both untreated and neuraminidase-treated 59Fe-IFLE in the presence of HI-NBCS. When spectrin, the major red cell cytoskeleton protein, was added to HI-NBCS there was a dose-related inhibition of the association with macrophages of both untreated and neuraminidase-treated 59Fe-IFLE. Moreover a mouse monoclonal antibody against spectrin promoted the interaction of neuraminidase-treated 59Fe-IFLE with macrophages. Mouse sera which supported the association of neuraminidase-treated 59Fe-IFLE with macrophages were found to contain anti-spectrin antibodies. These results suggest that IgG antibodies mediate the interaction between erythroblasts and macrophages via trypsin-sensitive and trypsin-resistant receptors on the macrophage surface and that at least some of the antibodies show specificity for spectrin.

Animals↗
PubMed1983

Interaction between erythroblasts and macrophages in vitro: effect of neuraminidase-treatment of erythroblasts and the role of serum factors.

Some factors influencing the interaction in vitro between dimethylsulphoxide-induced Friend leukaemia erythroblasts (IFLE) and syngeneic mouse peritoneal macrophages (M phi) have been investigated. Desialation of erythroblasts by treatment with neuraminidase resulted in a significant increase in their association with and ingestion by M phi. In addition, the interaction with M phi of both neuraminidase-treated and untreated IFLE was found to be influenced by a heat-stable serum factor. gamma-globulin markedly enhanced the weak IFLE-M phi interaction which occurred at low serum concentration suggesting that the heat-stable factor may be an immunoglobulin. Desialation of the IFLE-rendered them agglutinable by peanut lectin which was used as a probe for neuraminidase-induced membrane changes. By contrast, cycloheximide treatment of IFLE which also enhances their interaction with M phi, did not result in the exposure of receptors for this lectin. It is proposed that both desialation and cycloheximide treatment of IFLE lead to secondary alterations in their membrane structure which renders them recognizable by M phi.

Animals↗
PubMed1983

Impaired protein synthesis in erythroblasts enhances their phagocytosis by macrophages.

In an attempt to elucidate mechanisms which underly ineffective erythropoiesis, we investigated the effect of impaired macromolecular synthesis in erythroblasts on their phagocytosis by macrophages in vitro. Dimethylsulphoxide-induced murine Friend leukaemia erythroblasts were treated with inhibitors of RNA or protein synthesis and subsequently tested for their interaction with syngeneic mouse peritoneal macrophages in culture. Exposure of the erythroblasts to two reversible inhibitors of protein synthesis, puromycin and cycloheximide, enhanced their association with and phagocytosis by macrophages. The effect was evident after the drugs had caused a partial inhibition of protein synthesis and appeared to be reversible. By contrast, the treatment of erythroblasts with the inhibitor of RNA-synthesis, actinomycin D, which caused a marked depression of RNA but not of protein synthesis, failed to affect the interaction of erythroblats with macrophages. The results are in keeping with previous observations on human bone marrow showing impaired protein synthesis in erythroblasts in some haematological disorders characterized by a marked increase in ineffective erythropoiesis.

Animals↗
PubMed1982

The interaction of DMSO-induced murine Friend leukaemia erythroblasts with cultured syngeneic mouse peritoneal macrophages: an in vitro model for the study of ineffective erythropoiesis.

The interaction between dimethyl sulphoxide-induced Friend leukaemia erythroblasts (IFLE) and cultured syngeneic mouse peritoneal macrophages (PM phi) was assessed radiochemically as well as by light and electron microscopy. The data revealed that a small number of the IFLE either became attached to or were ingested by the PM phi and that the interacting IFLE were usually well differentiated. Interactions of a similar nature were also seen when IFLE were co-cultured with macrophages derived from mouse bone marrow. The extent of interaction between IFLE and PM phi provides a useful system in which mechanisms underlying ineffective erythropoiesis can be defined.

Animals↗
PubMed1975

The intracellular distribution of cathepsins and other acid hydrolases in mouse peritoneal macrophages.

Acid hydrolases, among them cathepsins A, B, C, and D, and their intracellular distribution have been studied in mouse peritoneal macrophages, a model commonly used for the study of mononuclear phagocyte functions in host-parasite relationships and in the immune response. Thioglycollate stimulated peritoneal macrophages showed high specific activities of acid hydrolases in compatison to liver and spleen. Fractionation of these macrophages by differential and isopycnic sucrose density centrifugation showed heterogeneous enyzme distribution patterns which were different for the various hydrolases studied. Thus, these enzymes appeared to be associated with particles of varying weight and density and in the different particles the ratios of the various acid hydrolase activities were quite dissimilar. With the majority of hydrolases a portion of the enzyme activity was found in fragile heavy particles of densities higher than 1.25 that sedimented together with the nuclei. Cultured macrophages derived from the non-irrated peritoneum exhibited a less heterogenous distribution pattern for acid phosphatase than did the thioglycollate stimulated cells. The heterogeneity of acid hydrolase distributions in the thioglycollate induced macrophages was attributed to their physiologic state of stimulated endocytosis causing a continuous formation of primary and secondary lysomes. Under certain conditions macrophages might contain lysosome-like particles with cathepsin ratios unfavorable for complete proteolysis. The existence of such particles is suggested as a possible explanation for the persistence of immunogenic protein within these cells.

Acetylglucosaminidase↗
PubMed1975

Modifications in the handling in vitro of 125I-labelled keyhole limpet haemocyanin by peritoneal macrophages from mice pretreated with the adjuvant Corynebacterium parvum.

Peritoneal macrophages were isolated from C. parvum-pretreated (CP) and normal CBAT6T6 mice and their in vitro handling of 125I-labelled Keyhole limpet haemocyanin (125I-labelled KLH) studied in relation to the humoral anti-KLH responses induced in corresponding animals. CP pretreatment exerted an adjuvant effect on the production of anti-KLH antibodies, both IgM and IgG, which was also demonstrable with a normally subimmunogenic dose of antigen. There was a clear difference between the handling of 125I-labelled KLH by CP and normal macrophages. The initial uptake of the antigen by CP macrophages was slower than that by normal ones. Moreover, 125I-labelled KLH was degraded to a lesser extent within CP macrophages, although the rates of antigen digestion were similar in both kinds of cells. The lower extent of 125I-labelled KLH degradation within the CP macrophages was due to a larger amount of antigen being retained on the cell membrane, where it escapes digestion. The findings suggest that intensified presentation to lymphocytes of antigen on the macrophage surface could be a causal factor in the adjuvant action of CP.

Adjuvants, Immunologic↗