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Biomedical subjects

H Franz

Publications and source records attributed to H Franz.

At least 73 records · Page 4Linked to original sources
PubMed1985

The in vitro activity of lectin I from mistletoe (ML I) and its isolated A and B chains on functions of macrophages and polymorphonuclear cells.

We investigated the effects of ML I and its isolated chains, A and B, in regard to selected functions of phagocytes (human granulocytes, paraffin-oil stimulated M phi from guinea pigs). On these cells, ML I has no cytotoxic effect between 10(-14) and 10(-8) (trypan blue exclusion and ethidium bromide exclusion). Over the same concentration range, ML I and B chain diminish the negative surface charge of M phi and agglutinate M phi at concentrations greater than or equal to 2 X 10(-8) M (ML I) and greater than or equal to 3 X 10(-7) M (B chain), respectively. The diminishing of the negative surface charge shows two peaks, indicating the existence of two types of receptors on the M phi surface with different affinities for sugar-binding sites. Moreover, the B chain shows a third peak at higher concentrations (3 X 10(-8) M) that could be inhibited by D-galactose (greater than or equal to 10(-4) M). In comparison, the A chain reduces the surface charge at concentrations over 3 X 10(-7) M, but D-galactose has no effect on this. By means of the agarose droplet test, the spontaneous migration of M phi is inhibited in the sequence ML I much greater than B chain greater than A chain. The phagocytic activity of human leukocytes tested with a radiometric phagocytosis technique reveals an increasing effect only for the B chain; ML I and the A chain have no effect. Perhaps the mechanism of the described activities of ML I and its B chain are comparable with the action of lymphokines activating M phi.

Animals↗
PubMed1985

[Histamine receptor-bearing lymphocytes. III. Suppression of immune reactions by killing of histamine receptor-bearing lymphocytes with a conjugate of histamine and the A chain of mistletoe lectin I].

Conjugates of the A-chain of the mistletoe lectin I and histamine but not A-chain per se inhibit the capacity of spleen cells of the mouse to induce antibody response or graft-versus-host reaction by 90%. The conjugates killed 27% of the spleen cells, 60% of the T-, and 15% of the B-lymphocytes. The receptors for histamine could be shown to be of the H2-type, because only H2-antagonists inhibited the toxic influence of the conjugates. The results suggest the hypothesis that not only suppressor cells but at least the majority of the immunocompetent cells bear receptors for histamine. The A-chain-histamine conjugate represents an "affinotoxin" which is cytotoxic only after affinity binding on receptors of the target cell.

Animals↗
PubMed1984

Demonstration of electron-dense material in clear synaptic vesicles using cationic ferrocenyl compounds.

Electron-dense material in clear synaptic vesicles in rat cerebral cortex and neuromuscular junctions of frog cutaneous pectoris muscle was demonstrated by using ferrocenyl cationics. Electron-dense spots were usually attached to the inner surface of the vesicular membrane. Control experiments (treatment with Triton X-100 or cetylpyridinium chloride; enzyme digestion with trypsin, hyaluronidase, neuraminidase, sulfatase and beta-glucuronidase) suggested that the electron-dense material is a glycoprotein.

Animals↗
PubMed1984

Immunological reactivity of tumor associated glycoproteins prepared by affinity chromatography.

Crude 3M KCl extracts prepared from tumor tissue and ascitic tumor cells of methylnitrosourea-induced fibrosarcoma of CBA mice or of a human stomach adenocarcinoma were gelfiltrated on Ultrogel AcA 34. Single fractions of these preparations were incubated with spleen cells of tumor bearing mice or blood peripheral lymphocytes. The response was detected by MEM-technique. Antigenic activities were found in molecular weight ranges from 200 to 300 kD (P1) and from 40 to 70 kD (P2). Single glycoproteins of the P1- and P2-fractions could be separated by affinity chromatography on immobilized D-galactose specific mistletoe lectin I, as detected by electrophoresis on microgradient gels (1.2-40%) or on SDS polyacrylamide slab gels. Especially the isolated glycoproteins of the P1-fractions are responsible for the observed antigenic reactivity, assayed in vitro by the MEM-technique and in vivo by foot pad swelling test.

Adenocarcinoma↗
PubMed1982

Some properties of con A-antibody conjugates.

By application of antibody-Con A conjugates it is possible to perform a modified enzyme immunoassay. The reaction of an antigen with the corresponding antibody labelled by Can A results in a complex to which POD can be bound via the carbohydrate moiety of the enzyme. The enzyme can be quantified in the usual manner. A special advantage consists in the applicability of relatively impure POD preparations.

Animals↗
PubMed1982

Isolation and characterization of a lectin from garden cress (Lepidium sativuum).

A lectin has been isolated from extracts of garden cress (Lepidium sativum) by affinity chromatography on human immunoglobulin-Sepharose. The lectin reacts with human erythrocytes without specificity for the A, B and 0 blood group. Erythrocytes of animal origin are also agglutinated by the lectin. The hemagglutinating activity is abolished by heating the lectin solution at 70 degrees C or by dialysis against strong acid buffers. The hemagglutination reaction is not inhibited by monosaccharides. Lectin-glycoprotein interactions are described and discussed.

ABO Blood-Group System↗
PubMed1982

The toxic A-chain of mistletoe lectin I: isolation and its effect on cell-free protein synthesis.

The reduction of Sepharose bound mistletoe lectin I (ML I) is a convenient method for preparing A- and B-chains under mild conditions. The B-chain represents the D-galactose binding moiety. The A-chain shows a significant dose-dependent inhibition of protein synthesis in cell-free systems from rat liver and rabbit reticulocytes, while pure B-chain preparations do not affect ribosomal translation processes.

Animals↗
PubMed1981

Isolation and properties of three lectins from mistletoe (Viscum album L.).

Three lectins have been isolated from an extract of mistletoe (Viscum album) by affinity chromatography on partially hydrolysed Sepharose and human immunoglobulin- Sepharose. The lectins differ in molecular weight and sugar specificity (lectin I, mol.wt. 11500, D-galactose-specific; lectin II, mol.wt. 60000, both D-galactose- and N-acetyl-D-galactosamine-specific; lectin III, mol. wt. 50000, N-acetyl-D-galactosamine-specific). All three lectins react with human erythrocytes without specificity for the A, B, and O blood groups. In contrast with abrin and ricin the mistletoe lectins cannot be divided into "toxins" and "haemagglutinins".

Carbohydrates↗
PubMed1980

Inhibition of protein synthesis by a toxic lectin from Viscum album L. (mistletoe).

1. The haemagglutinating and toxic lectin from Viscum album L. (mistletoe) inhibits protein synthesis in a lysate of rabbit reticulocytes, with an ID50 (concentration giving 50% inhibition) of 2.6 microgram/ml. This effect is enhanced (ID50 0.21 microgram/ml) if the lectin is reduced with 2-mercaptoethanol. 2. The lectin inhibits protein synthesis also in BL8L cells in culture. Inhibition occurs after a lag time of 3 h. The ID50 is 7 ng/ml, and increases after reduction of the lectin. 3. This and the gross lesions observed in rats poisoned with V. album lectin indicate this is a toxin very similar to ricin.

Animals↗