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Biomedical subjects

D Wallach

Publications and source records attributed to D Wallach.

At least 253 records · Page 14Linked to original sources
PubMed1980

Two interferon mRNAs in human fibroblasts: in vitro translation and Escherichia coli cloning studies.

Two mRNA species that produce biologically active interferon were isolated from human fibroblasts and studied by size fractionation and cloning in Escherichia coli plasmid pBR322. The major fibroblast interferon (Hu IFN-beta 1) is coded for by the smaller of the two mRNAs, an 11S species, 900 nucleotides long, which in cell-free systems yields a 20,000 Mr protein. The second interferon mRNA species (Hu IFN-beta 2) is 14S, about 1300 nucleotides long, and codes for another protein of 23,000-26,000 Mr. The two interferon mRNAs do not cross-hybridize. Both are induced by poly(rI.rC), but IFN-beta 2 mRNA is induced to about 10% in cells by cycloheximide treatment alone whereas under these conditions IFN-beta 1 is not induced.

Biological Assay↗
PubMed1978

Cyclic AMP-dependent phosphorylation of filamin in mammalian smooth muscle.

Filamin is a high molecular weight actin-binding protein found in large quantities in smooth muscle and other non-muscle cells. We have studied the phosphorylation of filamin in a mammalian smooth muscle, the guinea pig vas deferens. Intact vas deferens incorporated [32P]orthophosphate into filamin. Incubation of particulate fractions of vas deferens with [gamma-32P]ATP resulted in 32P-labeling of filamin. Cyclic AMP stimulated this phosphorylation, whereas cyclic GMP and Ca2+ had no effect. Purified vas deferens filamin can be phosphorylated by purified cyclic AMP-dependent protein kinase. We have compared cyclic AMP and cyclic GMP effects on phosphorylation in smooth muscle. Cyclic GMP stimulated phosphorylation of two particulate proteins, G-I (Mr = 130,000) a protein previously described by Casnellie, J. E., and Greengard, P. (1974) Proc. Natl. Acad, Sci. U.S.A. 71, 1891-1895 and G-III (Mr = 240,000). Both proteins and the kinase responsible for their phosphorylation appear to be membrane-bound. Phosphorylation of both proteins is stimulated by cyclic GMP (Ka = 3 x 10(-8) M), cyclic AMP (Ka = 3 x 10(-7) M), and to a lesser degree by Ca2+. In contrast, filamin phosphorylation is due to a soluble kinase stimulated only by cyclic AMP (Ka = 3 x 10(-7) M) and not by cyclic GMP or Ca2+.

Actins↗
PubMed1978

Filamin-actin interaction. Dissociation of binding from gelation by Ca2+-activated proteolysis.

Chicken gizzard filamin has been digested with purified Ca2+-activated protease. The subunits of (Mr = 250,000) of the protein are cleaved asymmetrically into two fragments, heavy merofilamin, Mr = 240,000, and light merofilamin, Mr = 9,500. Digestion is complete at substrate to enzyme ratios of 100:1 and requires Ca2+ concentrations in excess of 0.3 mM. Heavy merofilamin binds to F-actin as evidenced by cosedimentation with F-actin, by direct observation under the electron microscope, and by its ability to inhibit actin activation of heavy meromyosin ATPase. Heavy merofilamin does not form a gel when mixed with actin, except at very low concentrations of KCl. Thus, actin binding and gelation are separable activities of filamin. We speculate that Ca2+-stimulated proteolysis may play a role in the regulation of actin-filamin interactions.

Actins↗
PubMed1978

Purification of mammalian filamin. Similarity to high molecular weight actin-binding protein in macrophages, platelets, fibroblasts, and other tissues.

We have purified the high molecular weight actin-binding protein, filamin from guinea pig vas deferens. We find this mammalian filamin is very similar to chicken gizzard filamin in subunit molecular weight, amnio acid composition, actin-binding properties, immunological cross-reactivity, and the ability to be phosphorylated by cyclic AMP-dependent protein kinase. Anti-filamin antibodies cross-react with a high molecular weight macrophage actin-binding protein, and with a high molecular weight protein in platelets and fibroblasts. Furthermore like filamin, these proteins are also phosphorylated and cyclic AMP stimulates their phosphorylation. Anti-filamin antibodies do not cross-react with the erythrocyte membrane protein spectrin or with high molecular weight proteins in brain extracts. We conclude that filamin from avian and mammalian smooth muscle are very similar proteins and furthermore that many, but not all, non-muscle cells contain a protein closely related to filamin.

Actins↗
PubMed1978

[Auto-immune haemolytic anaemia and mediastinal dysembryoma in a 6-year-old child (author's transl)].

In a six-year-old girl, suffering from an auto-immune haemolytic anaemia, routine radiological examination revealed the presence of a mediastinal tumour which was removed surgically and proved to be a multiple tissue polycystic dysembryoma. Haemolysis and signs of anti-erythrocyte auto-immunisation disappeared after the operation and total and stable cure obtained with a follow-up of 15 months. The target antigen of the anti-erythrocyte autoantibody could not be found within the tumour. However, the latter contained lymphoid tissue and a considerable quantity of antibody. Although indirect, these findings offer arguments in favour of the secretion of autoantibodies by the dysembryoma.

Anemia, Hemolytic, Autoimmune↗
PubMed1978

Activation of adenylate cyclase in cultured fibroblasts by trypsin.

Adenylate cyclase activity measured in membranes of cultured normal rat kidney (NRK) fibroblasts was markedly increased by prior treatment of the intact cells with trypsin. Cell population density influenced the extent of activation observed. Trypsin treatment of sparse cells significantly enhanced adenylate cyclase activity, whereas similar treatment of confluent cells caused only a slight increase in adenylate cyclase activity. The degree of activation noted after trypsin treatment also varied depending on the adenylate cyclase function measured. Activity determined in the presence of GTP alone showed the greatest increase after trypsin treatment. Similar enhancement of adenylate cyclase activity of a washed cell membrane preparation was achieved by the addition of low concentrations of trypsin directly to the adenylate cyclase reaction mixture. The membranes of confluent NRK fibroblasts initially exhibited higher adenylate cyclase activity than did membranes of sparse cells. The present results suggest that this change in adenylate cyclase activity at cell confluence is not due to an increase in the amount of adenylate cyclase in the cell membrane but rather to a change in membrane components that regulate its activity. Proteolytic activation of adenylate cyclase appears to result from degradation of cell membrane proteins that modulate the activity of this enzyme.

Adenylyl Cyclases↗
PubMed1978

The anti-anaphylactic action of tiaramide hydrochloride.

Tiaramide hydrochloride (THC) is a new basic, non-steroidal, anti-flammatory drug. Its anti-anaphylactic action has been investigated using rat mast cells. It was found that THC exerts a strong inhibitory action on antigen-induced and compound 48/80-induced histamine release from rat peritoneal mast cells in a fluorometric assay. Compound 48/80-induced vasodilatation in rat skin is inhibited by prior intradermal injection of THC, as measured by blueing of skin due to intravascular Evans blue dye. THC also inhibits radio-labeled serotonin release from compound 48/80-challenged rat mast cells. In these experimental systems a similar action was exerted by disodium cromoglycate, but higher drug concentrations were needed. Further studies are needed to determine the exact mode of action of this drug and its eventual clinical use in the field of allergic diseases.

Anaphylaxis↗
PubMed1978

Cyclic AMP-dependent phosphorylation of the actin-binding protein filamin.

Filamin is a high molecular weight protein that binds to actin filaments in cells. It is found in large amounts in several different cells and tissues, including smooth muscle, fibroblasts, platelets, and macrophages. It is immunologically related to the previously described macrophage high molecular weight actin-binding protein but clearly different from erythrocyte spectrin. Filamin is a phosphoprotein; it is phosphorylated in vivo in intact tissues and cells. It can be phosphorylated in vitro with endogenous kinases; cyclic AMP stimulates this phosohorylation. Furthermore, the purified protein can be phosphorylated by purified cyclic AMP-dependent protein kinase. In smooth muscle homogenates, the stimulation of filamin phosphorylation by cyclic AMP is specific. Cyclic GMP and Ca2+ do not increase its phosphorylation, although they do stimulate phosphorylation of other proteins.

Actins↗
PubMed1977

Rosette-forming mast cells in rat anaphylaxis. Immunological characteristics of mast cell rosettes.

Peritoneal mast cells from immunized rats can form rosettes with antigen-coated sheep red blood cells. The receptor responsible for this active rosette formation is shown to be IgE cytophilic antibody: rosettes are inhibited by previous contact of mast cells with antigen, or with anti-IgE antiserum; the kinetics of mast cell rosettes following a primary immunization with ovalbumin and Bordetella pertussis vaccine is similar to the kinetics of reaginic antibody response. Furthermore, a reaginic serum can induce passive rosette formation. There is no correlation between cell-bound and circulating IgE.

Animals↗