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Biomedical subjects

M Papamichail

Publications and source records attributed to M Papamichail.

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

Establishment and characterization of a B-cell line from a patient with acute lymphoblastic leukemia.

A permanent lymphoblastoid cell line was established from the peripheral blood of a child with acute lymphoblastic leukemia. The cell line, designated SDK, grows in a stationary suspension culture, forming aggregates, in RPMI medium supplemented with 10% FCS, with a doubling time of 50-60 h. Immunologic markers and cytological features suggested that the SDK cells should be identified as being of B-cell origin. The cells failed to form rosettes with sheep erythrocytes, did not express T-cell antigens as defined by monoclonal antibodies, and exhibited surface and cytoplasmic immunoglobulin determinants. Chromosome analysis revealed the presence of three cell populations with (a) 46XY; (b) t(8q-; 14q+) or 2p-; 14q+) and (c) cells with unidentifiable markers. SDK demonstrated susceptibility to TPA-induced differentiation toward plasma cells.

Acid Phosphatase↗
PubMed1985

The biological effect of three thymosin fraction 5 polypeptides in the murine mixed lymphocyte reaction.

The biological effects of three thymosin fraction 5 polypeptides, designated as beta 10, beta 4, and alpha 1 were tested in the MLR of mouse splenocytes, lymph node cells and thymocytes against syngeneic or allogeneic stimulators. It was found that all three polypeptides, after in vivo and in vitro treatment of the responder cell population, could enhance the allogeneic MLR. These polypeptides were also able to induce significant syngeneic MLR in systems where responder cells were used against irradiated syngeneic splenocytes. In addition, while beta 4 was shown to have a weak stimulatory effect on allogeneic MLR utilizing thymocytes as the responder cell type, alpha 1 could strongly induce such responses when syngeneic splenocytes were included into the culture system. Preincubation of purified mature T cells or thymocytes with alpha 1 has shown these cells to be the target of this polypeptide action. Thus, it appears that thymosin fraction 5 polypeptides not only initiate differentiation processes of immature T cells, but also exert their effects on mature T lymphocytes.

Animals↗
PubMed1984

Polyadenylic acid polymerase activity in normal and leukemic human leukocytes.

Soluble polyadenylic acid [poly(A)] polymerase and poly(A) nucleases content of normal human blood lymphocytes and leukemic blood cell populations was determined. Blood lymphocytes from seven normal individuals were used as controls. Leukemic cells were obtained from 69 patients with various types of acute and chronic leukemias. Chronic lymphocytic leukemias presented poly(A) polymerase values with a mean of 9 +/- 4 (S.D.). Although most of the chronic lymphocytic leukemia cases presented poly(A) polymerase activities similar to those of normal lymphocytes (3 +/- 3), a small number fell into the specific activity values of acute leukemias, which were significantly higher and covered a wider range. The mean values for acute myeloblastic, acute monoblastic, and acute lymphoblastic leukemias were 53 +/- 50, 21 +/- 8, and 29 +/- 14, respectively. A statistically significant difference was found between chronic and acute leukemias (p less than 0.01). The observed differences in poly(A) polymerase levels of acute lymphoblastic leukemia versus chronic lymphocytic leukemia persisted after fractionation of the crude extracts and, furthermore, they could not be attributed to differences in the levels of poly(A)-degrading enzymes [poly(A) endo- and exonucleases]. Fractionation of leukemic extracts on Sephadex G-75 revealed two molecular forms of poly(A) polymerase activity.

Humans↗
PubMed1984

Mitogenic effects of glycolipoprotein extract from Pseudomonas aeruginosa.

Glycolipoprotein extracted from the extracellular of slime of Pseudomonas aeruginosa has been tested for its ability to cause murine spleen cells to proliferate and differentiate. The extracted glycolipoprotein was found to be mitogenic for a subpopulation of murine B cells. It also caused an increase in the number of specific antibody forming cells in vitro. The activity of this extract was sensitive to low doses of cyclosporin A. These findings may be important in understanding the mechanism(s) of host resistance to this organism.

Animals↗
PubMed1982

The detection of glucocorticoid receptors in breast cancer by immunocytochemical and biochemical methods.

Glucocorticoid receptors have been detected in 90 human breast tumors and tumor-like conditions by the immunoperoxidase method using a specific antibody against the glucocorticoid receptor isolated from rat thymocytes. In some of the specimens the [3H]-dexamethasone binding assay was also performed and the results obtained were compared with those of the immunoperoxidase method. When the biochemical method was used, no strict correlation between the degree of binding of [3H]-dexamethasone and malignancy on the basis of histological findings could be demonstrated. In contrast, the immunoperoxidase method was in full agreement with the histological type of the tumor. Thus, nearly all malignant breast tumors (carcinomas) were positive by the immunoperoxidase method to a vary degree. Most of the examined benign tumor-like conditions (fibrocystic disease) were found to be negative. Intermediate situations, such as atypical duct of lobular hyperplasia, papillomatosis etc, were mostly positive. These findings suggest that ther immunoperoxidase method, part from its usefulness for the detection of glucocorticoid receptors in breast tissue, may be used as an early biological marker to detect early conversion of normal to hyperplastic tissue and/or malignancy of the mammary gland.

Breast Neoplasms↗
PubMed1982

Activation of the alternative pathway of human complement by the extracellular slime glycolipoprotein of Pseudomonas aeruginosa.

The capability of the extracellular slime glycolipoprotein (GLP) of Pseudomonas aeruginosa to activate human complement was investigated. When slime GLP was added to type AB human serum, C3 and factor B were converted to their respective major cleavage fragments, C3b and Bb. This activation also occurred when slime GLP was incubated with serum-ethylene glycol bis(trichloroacetate)-Mg++, a result which indicates that the alternative complement pathway is involved. Additional support for the hypothesis of alternative pathway activation was provided by the fact that when serum-ethylene glycol bis(trichloroacetate)-Mg++ was preheated to inactivate factor B, slime GLP did not induce conversion of C3. The activation of the alternative pathway of human complement by slime GLP may represent an early nonimmune defense against P. aeruginosa infection.

Animals↗
PubMed1981

Inhibition of in vitro allogeneic reactions with disodium cromoglycate.

The antiallergic drug disodium cromoglycate (DSCG) selectively inhibits allogeneic responses in mixed lymphocyte culture (MLC) reactions, but does not affect cell viability or suppress lymphocyte responses to mitogens. Preincubation experiments with DSCG were without effect, indicating that the drug does not bind to unstimulated lymphocytes. Timed studies demonstrated maximal MLC inhibition when DSCG was added during the first 12 h or culture and no effect if added later than 72 h. Both natural killing and cell-mediated lympholysis (CML) assays proceeded normally in the presence of optimal MLC-inhibitory concentrations of DSCG. CML reactions were eliminated, however, by the presence of drug during generation of cytotoxic T cells. The proposed mode of action for DSCG is blocking of calcium influx across cell membranes, thereby inhibiting the release of mast cell and basophil granules in hypersensitivity reactions. Such a mechanism would seem unlikely for DSCG-mediated lymphocyte effects as several calcium-dependent lymphocyte functions are not obstructed.

Animals↗
PubMed1980

A method for analysing lymphocyte surface antigens.

A method is described for isolating and characterizing external lymphocyte surface proteins. Intact 125I-labelled tonsillar lymphocytes were incubated with antilymphocyte serum, solubilised with NP-40 precipitated with Staphylococcus aureus and the labelled proteins analysed on SDS polyacrylamide gels. The molecular weights of the proteins labelled in this way were compared with those of surface antigens labelled by the galactose oxidase method. This method may also be used for isolation of surface receptor molecules which lose their stereochemical structure upon solubilisation of the cells.

Animals↗
PubMed1980

A subpopulation of lymphocytes with T and B cell characteristics. Observations on two different cases of immunodeficiency.

We present the immunological studies on 2 patients, one with the Wiskott-Aldrich syndrome and another with common variable hypogammaglobulinemia. Although these patients represent two different immunodeficiency defects, both had a subpopulation of peripheral lymphocytes which had simultaneously T and B characteristics. Their peripheral blood mononuclear cells had a low responsiveness to polyclonal mitogens. We suggest that these unusual cells represent a subpopulation of suppressor cells or of immature T cells, which may have an essential role in the pathogenesis of these immunodeficiencies.

Adult↗
PubMed1980

Chlorpromazine and lidocaine inhibit antibody-dependent cell-mediated cytotoxicity but not erythrocyte antibody rosette formation.

Pretreatment of human peripheral blood mononuclear cells with chlorpromazine and lidocaine reduces their ability to induce lysis of antibody-coated target cells. This effect of local anesthetics was not due to a reduction of binding of antibody-coated red cells to the mononuclear cells, but it was rather probably due to the inhibition of mobility of the Fc receptor on the cell membrane.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1980

Release and reconstitution of Fc receptors from normal human mononuclear cells.

Nylon-fibre non-adherent cells isolated from human peripheral blood, release their Fc receptors for IgG upon culture in vitro in medium containing 0-2% foetal calf serum. The majority of Fc+ nylon-fibre non-adherent cells was reconstituted using supernates from different cell populations of human peripheral blood. The best reconstituting activity was detected in the supernates from glass-adherent cells, or unfractionated Lymphoprep cells, while those obtained from nylon-fibre non-adherent cells gave variable results sometimes containing no activity at all. It was shown that reconstitution was achieved by the uptake of Fc receptors present in the supernate which inhibited Fc rosette formation. Inhibition was also achieved with supernates from peripheral blood cells of a patient with monocytic leukaemia. Only autologous but not allogeneic cell supernates could reconstitute Fc receptors. This suggests that the reconstitution of Fc receptors on peripheral blood Fc-IgG lymphocytes by monocytic cells is under genetic control.

Cell Adhesion↗