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Biomedical subjects

U Pfüller

Publications and source records attributed to U Pfüller.

At least 55 records · Page 3Linked to original sources
PubMed1989

Selective killing of human monocytes by an immunotoxin containing partially denatured mistletoe lectin I.

The in vitro activity of an immunotoxin (IT) prepared by conjugating the monocyte specific RoMo-1 monoclonal antibody and partially inactivated Mistletoe lectin I (dMLI) containing inactivated B chain has been initially characterized. It is shown that while not affecting other mononuclear cells viability, this IT is capable of selectively destroying human monocytes after 24 h exposure thus resulting in the abrogation of monocyte support for PHA reactivity in mononuclear cell preparations. Therefore it seems to be possible to use this non-sugar binding holotoxin for immunotoxin preparation.

Antibodies, Monoclonal↗
PubMed1989

Visualization of anionic sites using polyethyleneimine-metal complexes.

17 Polyethyleneimine-metal complexes were synthesized and 3 of them were tested cytochemically for visualization of negative tissue charges. The demonstration of the anionic sites was carried out on rat cerebral cortex and on frog cutaneous pectoral muscle. As controls, neuraminidase digestion, methylation, and omission of osmium-postfixation were used. The osmiophilic properties of polyethyleneimine, polyethyleneimine salts, and polyethyleneimine-metal complexes were discussed.

Animals↗
PubMed1988

Demonstration of negative tissue charges by means of polyethyleneimine-metal complexes.

Three polyethyleneimine-metal complexes were synthesized and cytochemically tested for demonstration of negatively charged sites. For this purpose rat cerebral cortex synaptosomes were used. It was established that both types of polyethyleneimine-copper complexes labeled the synaptosomal membrane and synaptic vesicles with electron-dense granules, whereas the polyethyleneimine-lead complex marked the anionic sites with amorphous electron-dense material.

Animals↗
PubMed1988

A method for demonstration of lectin-binding sites using a blood group substance A/ferritin conjugate.

A new technique for demonstration of lectin-binding sites is proposed. At the 1st step of the method, the lectin binds the respective monosaccharide constituent of the glycoconjugate and at the 2nd step, the blood-group substance A-ferritin conjugate is used as a marker. The following lectins were tested: wheat germ agglutinin, soybean agglutinin, mistletoe lectin I, and concanavalin A. Human red blood cells were used as material. By means of control experiments, the specificity of the proposed technique was proved.

ABO Blood-Group System↗
PubMed1986

[Histamine receptor-bearing lymphocytes. VII. Antibody formation and graft-vs-host reaction from spleen cells after separation on histamine affinity columns].

Histamine-ovalbumin conjugates were characterized in respect to the relative amount of histamine residues which are accessible to membrane receptors. These conjugates were bound to a protein carrier. Spleen cells exhibited an enhanced reactivity in the adoptive antibody production as well as the graft versus host reaction after filtration through affinity columns with a low density of histamine residues. Contrary to that, the use of affinity columns with high histamine density led to a reduced immunoreactivity of the nonadherent cells. Consequently, controversial literature data concerning this problem seem to be based on methodological differences. The results support the hypothesis, that suppressor cells carry more histamine receptors than other immunoreactive cells.

Animals↗
PubMed1986

Histamine receptor-bearing lymphocytes (HRL). VIII. Splenopentin-accelerated reconstitution of the immunoresponsiveness after elimination of HRL.

The maturation effect of DA-SP5 on a spleen cell population depleted of immunocompetent, histami nereceptor-bearing lymphocytes was examined. Conjugates of histamine and the A-chain of the mistletoe lectin I killed in vitro these cells and abolished, as shown in a previous paper, their humoral and cellular capacity by around 90%. Sublethally irradiated mice were reconstituted with the remaining cells and treated with DA-SP5 (3 intraperitoneally injections of 10 micrograms DA-SP5 per week). The strong accelerating action of DA-SP5 on the restoration of the antibody response is interpreted as an effect of DA-SP5 on the maturation of B- and T-cells under in vivo conditions.

Animals↗
PubMed1985

Distribution of negative charges of rat brain synaptosomes established by means of protamine-ferritin conjugate.

The negative electric charges on the synaptosomes from rat cerebral cortex were studied by means of protamine-ferritin conjugate. The synaptic vesicles in some synaptosomes were heavily labelled with the positively charged conjugate. The synaptosomal membranes including presynaptic and postsynaptic membranes were also stained but in a lesser degree. It was established that the major dense line and the intraperiod line of myelin contaminants were labelled, too.

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↗
PubMed1981

Histamine release from rat mast cells induced by protamine sulfate and polyethylene imine.

The protamine sulfate-induced release of histamine from mast cells in a non-cytotoxic reaction, similar to the 48/80-induced secretion. Polyethylene imine was found to be a less potent releaser. It is a cytotoxic substance without specificity for mast cells and acts on membranes generally. Although the two agents are related concerning their molecular weight and polybasicity, their mode of action on mast cells is clearly different.

Animals↗
PubMed1980

[Use of solubilization for the preparation of samples for determination of heavy metals in biological materials using atomic absorption spectrophotometry].

Solubilisation was tested for its suitability to prepare organic samples for metal determination. Flameless atomic-absorption spectrophotometry was used as test method. Copper, manganese, zinc, and chromium levels were determined from various organ systems of Wistar rat, in response to "normal" feeding of pelletised standard feed. A comparison between experimentally established concentrations, on the one hand, and literature data, on the other, suggested that solubilisation was applicable with good success to the preparation of samples from which to determine reliable values, in ppm and ppb, of the above elements.

Animal Feed↗
PubMed1980

[Control of trace elements in the rat using the heavy metal antidote "Unithiol" (sodium-2,3- dimercaptopropane sulfonate)].

The trace element balance in laboratory rats was found to be affected by somewhat lasting application of "Unitiol". Unambiguous decline of manganese, copper, and zinc concentrations was recorded from blood and liver. Complex fixation of copper was stronger than that of the other elements tested. No dose-dependent changes were observed with the experimental arrangement described. The chromium levels in all examined organs were affected but slightly or not at all. The proposal is made that long-term therapeutic use of chelate formers should be accompanied by properly balanced application of essential trace elements.

Animals↗
PubMed1978

[Electronmicroscopic-histochemical demonstration of acid mucopolysaccharides using cationic ferrocenyl compounds (author's transl)].

Long-chain ammonium compounds with ferrocenyl groups were synthesized and used for the light (sudanophilia) and electron microscopic (electron dense staining by the iron of the ferrocenyl group) localisation of acid mucopolysaccharides. At least 5 of the 39 prepared ammonium salts produce a very good contrast. Cetyl-ferrocenylmethyl-dimethyl ammonium chloride has been found to be the best blocking agent and stain for acid polysaccharides.

Animals↗
PubMed1977

Sudan Black B: chemical structure and histochemistry of the blue main components.

Sudan Black B contains two blue main components, SSB-I and SSB-II. Their chemical structures were determinated by the aid of two-dimensional thin-layer chromatography, column chromatography, absorption, IR, mass, H1-NMR, and C13-NMR spectroscopy and were proved by alternate synthesis. SSB-I has been found to be 2,3-dihydro-2,2-dimethyl4-[(4-phenylazo-1-naphthalenyl)-azol]-1H-perimidine. For SSB-II was confirmed the known structure 2,3-dihydro-2,2-dimethyl-6-[(4-phenylazo-1-naphthalenyl)-azo]-1H-permidine. Relations of chemical structure of SSB-I and SSB-II to their staining properties are discussed.

Azo Compounds↗