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Biomedical subjects

U Pfüller

Publications and source records attributed to U Pfüller.

70 records · Page 4Linked to original sources
PubMed1977

[A method for the preparation and purification of the two blue main components of sudan black B (author's transl)].

Two dimensional thin layer chromatography of four commercial samples of Sudan Black B reveals two blue main components (SSB I and II) and at least 38 further fractions. The quantitative composition of one sample was estimated. SSB-I and SSB-II were isolated and purified by column chromatography supplying amounts for histochemical use. Histochemical experiments are described.

Chromatography, Thin Layer↗
PubMed1976

[Effect of protamine sulphate on erythrocyte agglutination by anti-rh antisera. Cause of time-dependence (author's transl)].

The effect of protamine sulphate on Rh antisera causes agglutination also in saline milieu and is time-dependent. Synchronous to the serologically demonstrable decrease of the protamine concentration a normalization of the immunoelectrophoretic picture (especially of the albumin arc) and a decline of the precipitate formation by heparin occur. These effects are based on enzymatic degradation of protamine by a protaminolytic enzyme contained in human serum. This enzyme could not be inhibited by sodium fluoride, sodium azide, ammonium oxalate, EDTA or alpha, alpha'-dipyridyl to a serologically desired degree. The change of the behaviour with regard to agglutination of human erythrocytes in the system Rh antibody - protamine sulphate results primarily from blocking acid groups on the erythrocyte surface and not from chemical modification of IgG antibodies. In this system protamine sulphate leads to the formation of agglutinates but it does not represent an obligate constituent of the formed agglutinate.

ABO Blood-Group System↗
PubMedDate not supplied

Thionins from Viscum album L: influence of the viscotoxins on the activation of granulocytes.

BACKGROUND: Extracts from European mistletoe (Viscum album L.) are applied in adjuvant cancer treatment, and some components, especially the mistletoe lectins (ML) have been immunologically characterised, but not the thionins, termed viscotoxins (VT). MATERIALS AND METHODS: The influence of the VT on human granulocytes was studied by flow cytometry: E.coli co-stimulated respiratory burst by oxidation of dihydrorhodamine 123 to rhodamine 123 and phagocytosis by ingestion of FITC-labelled E.coli. RESULTS: VT (25 and 250 micrograms/ml), in contrast to ML, significantly enhanced phagocytosis and burst activity. VT-rich mistletoe extracts also exerted significant effects. In addition, E.coli-activated granulocytes positively stain with Annexin-V and propidium iodide only due to 250 micrograms/ml VT incubation, suggesting that at this concentration burst activity was induced by the physiological activity of granulocytes after microbial ingestion and also by cytotoxic effects. CONCLUSION: Viscotoxins exert yet unknown strong immunomodulatory effects on human granulocytes, which might be of benefit for tumour patients, in addition to their cytotoxic properties.

Adjuvants, Immunologic↗
PubMedDate not supplied

Induction of Fas ligand (CD95L) by the toxic mistletoe lectins in human lymphocytes.

BACKGROUND: Fas ligand (FasL, CD95L) predominantly expressed on activated cytotoxic T cells and NK cells triggers apoptosis in Fas receptor (Apo-1, CD95) positive target cells. We investigated the expression of FasL, Fas and tumor necrosis factor (TNF) receptor 1 (TNF-R1, CD120a) on cultured human lymphocytes and leukemic T and B cells. MATERIALS AND METHODS: Lymphocytes from six healthy individuals, from four patients with chronic lymphocytic T or B cell leukaemia, and leukemic Molt-4 cells were incubated with the apoptosis- inducing mistletoe lectins (ML I and ML III). RESULTS: Incubation of differentiated lymphocytes with the ML resulted in a significant upregulation of FasL in the surviving CD4+ T helper cells, CD8+ cells and CD19+ B cells. Similarly, the TNF receptor expression increased, while the Fas molecule decreased. In contrast, FasL was not induced in leukemic cells. CONCLUSIONS: Apart from a direct induction of apoptosis in response to an inhibition of protein synthesis by the enzymic ML A chain, ML treatment may indirectly induce apoptosis in Fas+ tumour cells through activated FasL+ lymphocytes.

Antigens, CD↗
PubMedDate not supplied

Influence of polysaccharides from Viscum album L. on human lymphocytes, monocytes and granulocytes in vitro.

BACKGROUND: An acidic arabinogalactan from European mistletoe (Viscum album L, VAL; 1.34 x 10(6) Dalton) was studied in detail because its immunological properties are poorly characterised. MATERIALS AND METHODS: Flow cytometric studies focussed on PS-activated proliferation of human lymphocytes measured via incorporation of bromo-deoxyuridine (BrdU), granulocyte phagocytosis via ingestion of FITC-labelled E.coli, and respiratory burst via oxidation of dihydrorhodamine 123 to rhodamine 123. Cytokines were detected in the cell culture supernatants by ELISA. RESULTS: PS, in contrast to mistletoe lectins (ML), significantly stimulated proliferation of CD4+ T-cells but not CD8+ and CD19+ cells. However, ML influenced PS-mediated stimulation, with a synergistic effect in one and an inhibitory effect in another individual. Furthermore, IFN-gamma release was significantly enhanced by PS, favouring a T-helper cell type-1 cytokine pattern, further IL-6 was significantly stimulated, while granulocyte activity was not affected. CONCLUSIONS: VAL-PS exert yet unknown stimulatory activities, especially on specific CD4+ T-cells which may be influenced by other extract components like the ML. These components may contribute to the anti-tumour effect of VAL.

Adjuvants, Immunologic↗
PubMedDate not supplied

Viscotoxin-free aqueous extracts from European mistletoe (Viscum album L.) stimulate activity of human granulocytes.

BACKGROUND: Extracts from European mistletoe (Viscum album L., VAL) are used for complementary cancer treatment. Viscotoxins (VT) and whole plant extracts with high amounts of the VT have been shown to stimulate functional activity of granulocytes. MATERIALS AND METHODS: We stimulated neutrophils from healthy donors in vitro with aqueous VT-free VAL extracts and mistletoe lectins (ML) in the presence of E.coli and studied phagocytosis (via incorporation of FITC-labelled E.coli) and respiratory burst (via oxidation of dihydrorhodamine 123 to rhodamine 123) by flow cytometry. RESULTS: The VT-free VAL extract significantly stimulated granulocyte activity, and this effect correlated with the content of the ML, although the ML exerted no influence at relevant concentrations. Co-incubation of the cells with VAL in the presence of VT further increased granulocyte response. CONCLUSIONS: From these data it is suggested that (1) a non-VT non-ML component of the VAL extracts activated granulocytes and (2) different activation pathways may be involved in the stimulation by the whole plant extract and the VT.

Granulocytes↗
PubMedDate not supplied

Differential binding of toxic lectins from Viscum album L., ML I and ML III, to human lymphocytes.

The killing capacity of extracts from Viscum album L., widely used as an adjuvant in complementary cancer therapy, is dependent on the content of toxic proteins, especially the mistletoe lectins (ML). Although one may expect a homogeneous distribution of 'receptors' for these proteins on the cell surface, the sensitivity of cells to the ML-mediated cytotoxicity obviously differs, as the galNAc-binding ML III in contrast to the gal-binding ML I selectively killed CD8+ lymphocytes with a 'memory' phenotype (CD62Llo), while CD19+ B cells remained almost unaffected. B cells hardly bind ML III but did bind the gal-specific ML I. In accordance with these observations, in leukaemic B cells from patients with B chronic lymphocytic leukaemia and the human IgE-secreting myeloma cell line U-266 a strong induction of apoptosis-associated mitochondrial Apo2.7 molecules was observed after treatment with ML I and less effectively by ML III, while in the leukaemic T cell line Molt-4 both ML were strong inductors of apoptosis. In the light of these findings, the possible impact of ML I- and ML III-rich mistletoe extracts in the treatment of B cell neoplasia has to be carefully investigated.

Apoptosis↗
PubMedDate not supplied

Toxic proteins from European mistletoe (Viscum album L.): increase of intracellular IL-4 but decrease of IFN-gamma in apoptotic cells.

BACKGROUND: Mistletoe lectins (ML), the major biologically active components of mistletoe extracts, which are used for adjuvant cancer therapy, induce apoptosis in lymphocytes and tumor cells. In addition, ML at toxic concentrations induce the release of cytokines, but it remains unclear as to whether dying or activated cells are responsible. MATERIALS AND METHODS: By flow cytometry, expression of IFN-gamma, IL-4, apoptosis marker Apo2.7 and anti-apoptotic Bcl-2 proteins were analyzed in response to ML or viscotoxins (VT) in PBMC from controls and plasmocytoma cells (U-266). RESULTS: While ML inhibited PMA/Ca-ionophore/monensin co-stimulated IFN-gamma production, they increased IL-4 expression in CD8+ and CD4+ T-cells. Thereby, IL-4 was mainly expressed in apoptotic cells with a low level of Bcl-2 proteins. In contrast, the cell membrane permeabilising VT induced complete loss of Bcl-2 proteins but did not stimulate IL-4 production within 24 hours, indicating that IL-4 expression is related to apoptosis but not to necrosis. CONCLUSION: Despite the role of IL-4 during activation of type2 T-helper cells, IL-4 expression may play an important yet undefined role during apoptosis of normal and tumor cells.

Apoptosis↗
PubMedDate not supplied

Intracellular expression of IL-4 and inhibition of IFN-gamma by extracts from European mistletoe is related to induction of apoptosis.

BACKGROUND: Extracts from European mistletoe are used for adjuvant cancer treatment. Their influence on the intracellular expression of cytokines of the T-helper cells type-1 (Th1; IFN-gamma) or type-2 (Th2; IL-4) is still unknown. MATERIALS AND METHODS: Lymphocytes from controls were incubated with mistletoe extracts (ME) and mistletoe lectins (ML) for 24 hours and co-stimulated with PMA/Ca-ionophore/monensin during the last 6 hours. Apoptosis and intracellular cytokine expression were detected by flow cytometry, the cytokine release into the supernatants by ELISA. RESULTS: ME and ML significantly inhibited intracellular expression of IFN-gamma but stimulated IL-4. Thereby, IL-4 was mainly expressed in apoptotic (Apo2.7+) cells. However, IFN-gamma secretion into the supernatants of the cells was dose-dependently inhibited by ME and ML, while IL-4 was not detected at all. CONCLUSION: The intracellular expression of the 'Th2-cytokine' IL-4 in ME- and ML-exposed cells may not be related to a typical Th2-response but rather to cell death. This effect might be of great relevance e.g. after intratumoural injection of the mistletoe extracts and, in general, for the inhibition of an inflammatory response during apoptosis.

Apoptosis↗
PubMedDate not supplied

Binding of mistletoe lectins to cutaneous malignant melanoma: implications for prognosis and therapy.

BACKGROUND: Glycoconjugates, as detected by lectin histochemistry, have been implicated in metastasis formation in many neoplasias. However, no data concerning the three mistletoe lectins (MLs) and the spread of malignant melanoma have been published. MATERIALS AND METHODS: The binding status of ML-I, -II and -III was histochemically assessed in 100 malignant melanomas and correlated with metastasis in a 10 year follow-up period. Furthermore, the staining intensity of the three MLs, scored from negative (-) to very intense (+ + +), was evaluated. RESULTS: Kaplan-Meier analsis revealed that very intense binding (+ + +) of ML-I was positively-correlated with metastasis (p=0.044). CONCLUSION: Since ML-I is specific for galactose, high density galactose expression in malignant melanoma is a predictor of poor prognosis.

Adjuvants, Immunologic↗
PubMedDate not supplied

Generation of reactive oxygen intermediates (ROI) by the thionins from Viscum album L.

BACKGROUND: Extracts from Viscum album L. are widely used as an adjuvant in complementary cancer therapy. While the mechanisms of mistletoe lectin (ML) cytotoxicity are well described, the viscotoxin (VT) effects are unclear at present. Thus, we treated human lymphocytes with VT and measured cell death-associated changes by flow cytometry. RESULTS: Treatment of lymphocytes with VT for 2 hours resulted in the binding of Annexin-V, permeabilisation of cell membranes, and generation of ROI. Apart from interindividual differences in response to VT, the number of intracellulary Bcl-2 proteins increased only marginally. The VT A1, A2, A3 and 1-PS were similar in their ROI-inducing potencies, while other cationic and/or amphipathic substances such protamine sulfate, VT B, purothionin or wasp venom peptides mastoparan I and II were less effective. However, the cytotoxic properties of VT-rich whole plant extracts from mistletoe grown on different host trees (Iscador), correlated with the content of ML rather than VT. CONCLUSIONS: Permeabilisation of lymphocytes cell membranes by VT was associated with generation of ROI within 2 hours indicating accidental cell death. VT cannot be ignored any longer as they posses both immunomodulating and cytotoxic properties, which both might be of clinical relevance.

Antimicrobial Cationic Peptides↗