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Biomedical subjects

T Bakács

Publications and source records attributed to T Bakács.

At least 55 records · Page 3Linked to original sources
PubMed1982

Inhibition of the anti-D antibody-dependent cellular cytotoxicity against O, Rh-positive (R1R2) erythrocytes by O,Rh-negative (rr) competitor cells.

Anti-D antibody-dependent lymphocyte-mediated lysis of O,Rh-positive (R1R2) erythrocytes was inhibited by O,Rh-negative (rr) erythrocytes in cold target competition experiments. The degree of inhibitory effects was different with the different antisera used for sensitization. Under the same conditions the inhibition varied between 23 and 79%. The difference did not relate to the titres of the sera.

ABO Blood-Group System↗
PubMed1982

Effect of cytostatics on the migration of leukocytes.

The effect of chemotherapeutic agents--cytosine arabinoside, methotrexate, procarbazine, vinblastine and vincristine--generally applied in the treatment of human cancer were tested on the motility of polymorphonuclear leukocytes. In the concentrations applied, cytosine arabinoside and procarbazine were inhibitory, vincristine had no effect, methotrexate and vinblastine stimulated the migration at lower concentrations.

Antineoplastic Agents↗
PubMed1982

[Phagocytosis measurement in Hodgkin's disease and Non-Hodgkin lymphoma-patients with a new radiometric assay (author's transl)].

A new radiometric assay for measurement of phagocytosis of opsonized Saccharomyces cerevisiae by human mononuclear cells and granulocytes is presented. This assay based upon the incorporation of 75Se-L-selenomethionine of the extracellular yeast cells after the ingestion step without a separation procedure for intracellular and extracellular microorganisms. Therefore the assay is objective, not time consuming and convenient for clinical application. After standardization of the method, in a preliminary study phagocytosis was evaluated in 44 individuals: 16 healthy controls, 13 patients with Hodgkin's disease and 15 patients with Non-Hodgkin-lymphoma before treatment. In comparison to normal controls the phagocytosis in the mononuclear cell fraction of cancer patients was increased and in granulocytes decreased. The most extensive phagocytosis activity was shown in the mononuclear cell fraction of patients with Hodgkin's disease.

Cell Separation↗
PubMed1981

[Angioimmunoblastic lymphadenopathy].

Cytological, histological and ultrastructural characteristics of a cose of an extranodal and nodal angioimmunoblastic lymphadenopathy persisting during several years are given. Angiomatous proliferation in the case reported seemed to be identical both in the lymph node and in the cutaneous infiltration. Types of cells seen in the angioimmunablastic lymphadenopathy did not differ from those of other immunoreactive processes. In the extranodal infiltrates in addition to other phenomena thickening of the immunological techniques decrease of the natural cytotoxicity and the number of T-lymphocytes could be observed.

Autoantibodies↗
PubMed1978

Interaction of the B95-8 and P3HR-1 substrains of Epstein-Barr virus (EBV) with peripheral human lymphocytes.

Two substrains of the Epstein-Barr virus derived from the B95-8 and P3HR-1 cell lines were studied for their interaction with human peripheral lymphocytes. It has been previously shown that B95-8 virus has and P3HR-1 virus lacks lymphocyte-transforming ("immortalizing") properties. DNA stimulation induced by B95-8 virus showed a good correlation with the number of surface Ig-positive cells. P3HR-1 virus added before B95-8 virus completely abolished the stimulation of DNA synthesis. It also prevented EBNA induction by B95-8 virus. P3HR-1 virus added after B95-8 virus diminished DNA stimulation by the latter in a time-dependent fashion. P3HR-1 virus did not inhibit DNA stimulation by phytohaemagglutinin but was inhibitory if added before a B cell mitogen (Staphylococcus Aureus). The origin of P3HR-1 virus and its relationship to the transformation process are discussed.

Antigens, Viral↗
PubMed1978

Inhibition of DNA metabolism in human B lymphocytes by a substrain of Epstein-Barr virus (P3HR-1): a method for virus quantitation.

Pretreatment with the P3HR-1 substrain of Epstein-Barr virus (EBV) inhibited approximately 85% of the DNA stimulation induced by Staphylococcus aureus in human B lymphocytes. In parallel experiments, the DNA stimulation induced by the transforming B95-8 substrain of EBV was almost completely inhibited by prior exposure to P3HR-1 virus. Phytohemagglutinin stimulation was only slightly inhibited, whereas the DNA synthesis of continuously growing Raji cells was inhibited to a considerable extent. The degree of DNA inhibition was correlated with the induction of the EBV-determined antigens (membrane, early, and nuclear antigens) in sensitive indicator cells.

B-Lymphocytes↗
PubMed1978

Human blood lymphocyte fractionation with special attention to their cytotoxic potential.

In studies concerning the natural cytotoxic activity of human blood lymphocytes we have found that: 1. T cell, which rosette with sheep erythrocytes can be separated by centrifuging on Ficoll the lymphocyte and erythrocyte mixture without previously pelleting and incubating in the cold. 2. Lysis of marker erythrocytes with ammonium chloride impairs the cytotoxic activity of lymphocytes. Incubation at 37 degrees C for 12 hr prior to the test restores the activity to some extent. 3. A high proportion of the so call "null" fraction i.e. cells remaining in the interface after removal of B cells (passage on nylon column) and sedimentation of E rosettes, sediments as rosettes with sheep EAC'indicating that these cells carry low density E and C3 receptors. Rosetting with SRBC or ox EAC' gave significantly lowr values. On a per cell basis the "null" fraction was the most efficient one in natural cytotoxicity. Depletion of cells with low affinity E or E and C3 receptors left highly active subfractions.

Ammonium Chloride↗
PubMed1977

Characterization of human lymphocyte subpopulations for cytotoxicity against tumor-derived monolayer cultures.

Lymphocyte fractions of three healthy donors were tested for cytotoxicity in a 48-h assay on several tumor-derived lines. Analysis of surface markers indicated that a non-T non-B fraction comprising about 50% Fc-receptor-positive cells was most potent. The cell yield in this fraction was on the average 6.5% of the non-fractionated population. Elimination of Slg positive cells did not influence the cytotoxic potential. Pure T cells isolated with E-rosetting subsequent to passage on nylon wool column had no or very low low cytotoxicity. We had indications that cells without conventional markers--"null" cells--were also cytotoxic.

Cell Line↗
PubMed1977

Mitogenicity of fetal calf serum.

The mitogenic effect of fetal calf serum (FCS) has been studied. Human lymphocytes, especially cord blood cells, undergo blastogenesis in media supplemented with FCS. The mitogenic effect is exerted on non-T (B and null) lymphocytes, but not on T cells. Bovine serum albumin (BSA) successfully substitutes for FCS in mitogen-induced lymphocyte blastogenesis. Unlike FCS, it has no mitogenic properties.

Animals↗
PubMed1977

Fc receptors on human blood B lymphocytes.

The frequency of Fc-receptor positive B lymphocytes in human blood was investigated. Under the conditions used heat-aggregated gammaglobulin binding and EA(ox)-rosette formation labelled the same lymphocyte populations. Using various techniques, double marking and cell separations the proportion of Fc-receptor positive cells within the surface Ig carrying population was estimated to be between 11-8 and 36-2%. The proportion of SIg carrying cells within the population forming EA-rosettes was between 11 and 26-4%. This represents extreme values due to known technical circumstances.

B-Lymphocytes↗
PubMed1976

Search for anti-tumor response in a bone tumor patient with a long clinical history.

Immunological studies are presented on a patient with a long clinical history suggesting the existence of a tumor-specific immune response. His tumor, first considered benign, progressed to a highly malignant osteosarcoma. Cell-mediated immune reactivity against biopsy cells and against tumor extract was detected in vitro by the autologous tumor stimulation test (ATS) and in vivo by the skin test. In one ATS-test with tumor extract, blastogenesis of T-cells was demonstrated. The amount of Ig(s) in consecutive biopsies increased. Biopsies taken in the later period of the disease stimulated only after trypsin treatment. This stimulation was inhibited by autologous serum or acid eluate of the biopsy. The inhibitory factor in the serum was not intact immunoglobin. Blood lymphocytes did not show a discriminatory or disease-related cytotoxicity, either directly or after co-cultivation with the tumor material. Lymphocytes isolated from one biopsy were non-reactive in both the ATS and the cytotoxicity test.

BCG Vaccine↗