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Biomedical subjects

D Bubeníková

Publications and source records attributed to D Bubeníková.

At least 19 recordsLinked to original sources
PubMed1995

Interleukin-2 gene therapy of residual EL-4 leukaemia potentiates the effect of cyclophosphamide pretreatment.

Experiments were designed to investigate a possible therapeutic role of interleukin-2 (IL-2) gene transfer in the model of murine (EL-4) leukaemia pretreated with cyclophosphamide. It has been found that i.p. pretreatment of the leukaemic mice with cyclophosphamide, followed by i.v. administration of irradiated cells, genetically engineered to produce IL-2 and used as a source of the cytokine (IR-IL-2 cells), cured a substantial percentage of the leukaemic mice. Neither treatment with cyclophosphamide nor administration of the IR-IL-2 cells alone had any significant therapeutic effect. Labelling of the EL-4 and IR-IL-2 cells with different fluorescent cell linkers followed by i.v. injection and detection of the labelled cells in cryostat sections of various organs has shown that both cell populations can be detected almost exclusively in the red pulp of the spleen, close to the white pulp nodules, thus providing the possibility of short-range local interactions among the IL-2-producing cells, IL-2-responsive defence effector cells and EL-4 leukaemia targets.

Animals↗
PubMed1994

Gene therapy of plasmacytoma: comparison of the therapeutic efficacy of tumour cells transduced with the interleukin-2, interleukin-4, or interleukin-6 genes.

The present study was designed to compare the tumour inhibitory effects of local therapy based on insertion of cloned IL-2, IL-4, or IL-6 genes into the genome of murine plasmacytoma X63-Ag8.653, followed by injection of the genetically modified cells to the vicinity of the parental plasmacytoma growing in syngeneic mice. It was also designed to investigate the effects of combined gene therapy with IL-2- and IL-6-producing plasmacytoma cells. It has been found that insertion of the IL-2 gene into the genome of X63-Ag8.653 cells can abrogate tumorigenicity of the transduced cells more effectively than insertion of the IL-4 or IL-6 gene. Peritumoral administration of the genetically modified plasmacytoma cells producing IL-6 (X63-h-IL-6) resulted in a therapeutic effect comparable with that of the IL-2-producing cells (X63-m-IL-2), whereas no substantial therapeutic effect of IL-4-producing cells (X63-m-IL4) was observed. The combined gene therapy with IL-2- and IL-6-producing cells did not give any additive or potentiated therapeutic effect.

Animals↗
PubMed1993

Utilization of interleukin-2 gene transfer in local immunotherapy of cancer.

It has been previously found that local administration of Balb/c plasmacytoma cells transformed and made non-tumorigenic by insertion of the cloned murine interleukin-2 (IL-2) gene induced regressions of a variety of murine tumours including the original Balb/c plasmacytoma X63-Ag8.653 growing in syngeneic mice. The tumour-inhibitory effect of the plasmacytoma cells transformed by IL-2 cDNA and designated as X63-m-IL-2 was due to their high constitutive production of IL-2. Here we show that admixture of syngeneic spleen cells to the X63-m-IL-2 transformants substantially (P < 0.025) increased the antitumour efficacy of the transformants. Balb/c spleen cells co-cultivated with X63-m-IL-2 cells in vitro yielded predominantly Thy 1.2+, CD3+, LFA-1+ lymphocytes, cytolytic for the X63-Ag8.653 plasmacytoma as well as for other murine tumours, including the X63-m-IL-2 target cells.

Animals↗
PubMed1993

Therapeutic efficacy of repeated cycles of local IL-2 injections in mice carrying slowly growing tumour grafts.

Local IL-2 administration prior to transplantation of murine sarcoma virus (MSV Harvey)-induced tumour MSVT2 provided a model of slowly growing tumours suitable for long-term investigation of the therapeutic efficacy of repeated IL-2 injection cycles. Challenge of mice with the dose of sarcoma cells, which was lethal for 20/20 untreated control recipients, revealed that 8/20 IL-2-pretreated mice were protected by the local IL-2 treatment and survival indefinitely. Nine out of twenty IL-2-pretreated mice died during the same time period as the control mice, i.e., during 36 days, and 3/20 IL-2 pretreated mice were tumour-negative until day 60, when incipient tumours arose. The three late tumours were used as a model to investigate the therapeutic efficacy of the new cycles of repeated local IL-2 administration. It was found that no resistance to IL-2 immunotherapy was induced by pretreatment of the late tumours and that the tumours were repeatedly susceptible to local IL-2 treatment. Spleen cells of the tumour-bearing mice, which were not cytotoxic for MSVT2 tumour cells in vitro, could be made cytotoxic by addition of exogenous IL-2.

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PubMed1992

Use of IL-2 gene transfer in local immunotherapy of cancer.

Insertion of functional interleukin-2 (IL-2) gene into a plasmacytoma cell line X63-Ag8.653 substantially reduced tumorigenicity of the resulting cloned cells, designated as X63-m-IL-2. Peritumoral administration of the X63-m-IL-2 cells, producing constitutively large quantities of IL-2, resulted in regressions of established X63-Ag8.653 plasmacytomas growing in the peritoneal cavity of syngeneic mice. In vitro activation of BALB/c spleen cells by co-culture with X63-m-IL-2 cells or their supernatants gave rise to cytotoxic lymphocytes with lymphokine-activated killer (LAK) activity against syngeneic X63-Ag8.653 plasmacytoma and other tumor targets. In contrast, peritumoral administration of X63-Ag8.653 cells carrying an inserted interleukin-4 (IL-4) gene (designated X63-m-IL-4 cells) and producing constitutively large quantities of IL-4 did not result in a therapeutic effect. Moreover, the admixture of the X63-m-IL-4 and X63-m-IL-2 cells substantially diminished the X63-m-IL-2 cell-mediated therapeutic effect. Similarly, IL-4-containing supernatants generated from X63-m-IL-4 cell cultures substantially diminished LAK activation by X63-m-IL-2 cell produced supernatants.

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PubMed1990

Hemoblastoses in mice contaminated with low activities of 239Pu.

Female ICR mice were injected intravenously with low activities of 239Pu (3.0 kBq, 6.0 kBq, 12.3 kBq/kg). In these mice with high spontaneous incidence of hemoblastoses the occurrence of myeloid leukemia, lymphocytic leukemia, lymphosarcoma, reticulum-cell sarcomas and osteosarcoma was studied. Hemoblastoses, on the whole, remained in their numbers radiation-independent, nevertheless, the distribution into specific types changed, with moderate prevalence of myeloid and lymphocytic leukemia and lymphosarcoma. After plutonium injection the mean survival time of mice bearing myeloid and lymphocytic neoplasias was significantly shorter than the survival of mice that died of retothelosarcoma and from other causes. These contamination-dependent differences could not be observed in matched controls. As expected, 239Pu activities used in this experiment induced osteosarcomas. Whereas in leukemogenesis alpha-radiation appeared as a factor promoting and modifying the leukemogenic process, in osteosarcoma the alpha-particles acted rather as an initiator, the effect of which was dependent on the dose to the endosteal progenitor cells.

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PubMed1988

Effect of plutonium-239 on the mitotic activity of mouse bone marrow cells.

Mitotic index of the bone marrow cells was studied in femoral bone marrow of mice given 313 kBq 239Pu kg-1. The attention was turned to the femoral midshaft and the mitosis concentration, intensified by Colcemid stathmokinetic effect, was evaluated in a sampling field from endosteal surface to the central venous canal, throughout 68 weeks. It has been found that the plutonium effect in the sampling band is rather uniform except the points in subendosteal zone early after plutonium injection, where the mitotic index was reduced in such a way that the mitotic gradient, observed in controls, was affected. The mitotic activity in femoral diaphysis of plutonium injected mice was mobilized approximately till the 30th week of contamination. Later it deteriorated progressively. The results are discussed and should not be regarded as representative for the entire bone marrow hemopoiesis.

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PubMed1987

Long-term effects of low-level 239Pu contamination on murine bone-marrow stem cells and their progeny.

The effects of long-term internal contamination with 13.3 kBq kg-1 239Pu injected intravenously were studied in 10-week-old ICR (SPF) female mice. Radiosensitivity of spleen colony-forming units (CFU-S) and 125IUdR incorporating into proliferating cells of vertebral bone marrow and spleens were determined in plutonium-treated and control animals one year after nuclide injection. The CFU-S in 239Pu-treated mice were more sensitive to X-rays (D0 = 0.52 +/- 0.01 Gy) than in controls (D0 = 0.84 +/- 0.02 Gy). 125IUdR incorporation into bone marrow and spleen cells was reduced after plutonium contamination. At one year following plutonium injection, the occurrence of chromosome aberrations was evaluated in metaphase figures of femoral bone marrow cells. The frequency of aberrations increased early after plutonium treatment, at later intervals it tended to decrease but not below the control level. While the relative numbers of vertebral marrow CFU-S decreased significantly, but only to 86 per cent of normal, cellularity of vertebral bone marrow, peripheral blood counts and survival of 239Pu-treated mice did not differ from the control data.

Alpha Particles↗
PubMed1985

Self-renewal capacity of murine hemopoietic stem cells under internal contamination with 239Pu and 241Am.

The self-renewal capacity of murine pluripotent hemopoietic stem cells (CFU-S) of vertebral bone marrow was studied under conditions of short-term and long-term internal contamination with 239Pu or 241Am in female mice. Measurement of the CFU-S self-renewal capacity was carried out using double transplantation assay. To evaluate the production of differentiated progeny of stem cells average erythroblast numbers/visible spleen colony and 59Fe-uptake/colony were computed. The marrow cellularity/vertebra and the number of CFU-S/vertebra were decreased and affected more by 239Pu than by 241Am. The production of erythroblasts per a single CFU-S and the 59Fe-uptake/colony were reduced, similarly the numbers of secondary spleen colonies and of secondary CFU-S in primary colonies. The above changes resulting from impaired functions of surviving CFU-S were more serious with 241Am than with 239Pu. The biological effects of plutonium and americium appeared independent of the phase of contamination.

Alpha Particles↗
PubMed1984

Phorbol myristate acetate-stimulated production of interleukin 2 by T-cell lymphoma and constitutive production by derived hybridomas.

To isolate a stable tumor cell line source of IL-2 (TCGF), 19 murine T-cell lines and their derivatives were screened for both constitutive and mitogen-stimulated IL-2 production. The cloned subline of a mouse thymic lymphoma EL-4 designated as EL-4TF could be stimulated with PMA to produce 80 U/ml of IL-2. A TK- EL-4TFR mutant line has been selected from the EL-4TF cell population by treatment with 5-BrdUrd. The EL-4-TFR cells were stimulated with PMA and fused with the cells of thymic lymphoma BW5147. The resulting BH3 hybrid cell population was repeatedly cloned and tested for constitutive IL-2 production: two of the BH3 hybridoma clones were found to produce IL-2 constitutively. The IL-2 of EL-4TF origin was found to support permanent in vitro growth of IL-2 dependent, tumor-specific T killer cell line CTLL when present in culture medium at a concentration of at least 0.1 U/ml. Since the EL-4TF-derived IL-2 preparations were contaminated with PMA, it was of interest whether PMA alone has a growth-promoting activity in CTLL cell cultures. Permanent cultivation of CTLL cells in an IL-2-free medium containing PMA was not possible. However, both mitogenic and co-mitogenic effects of PMA on CTLL cells were observed.

Animals↗
PubMed1983

Thy-1 epitopes are expressed on murine myeloid leukemia and reticulum sarcoma cells.

Expression of Thy-1.2 specificities in cells from 29 primary spontaneous leukemias of random-bred ICR Swiss mice was examined by cell membrane and cytoplasmic immunofluorescence with monoclonal HO-13-4 antibody [1]. The Thy-1.2 epitopes were detected in all thymic lymphomas and were absent in the lymphomas of non-thymic origin. Unexpectedly, the Thy-1.2 epitopes were also detected in 71% (5/7) of myeloid leukemias and 40% (4/10) of reticulum cell sarcomas examined.

Animals↗
PubMed1983

T-cell hybrids. IV. One of parental cell lines is dominant in determining membrane characteristics of hybrid cells.

Membrane characteristics of parental thymic lymphoma cells (BW5147, EL-4R) and their hybrids (BH2) derived by PEG-promoted cell fusion were compared. Isoelectric focusing of the cell populations, titration of membrane proton binding groups and quantitative examination of cell-substrate adhesiveness indicated that the BW5147 cells behaved as dominant in determining cell membrane characteristics of the BH2 hybrids.

Animals↗
PubMed1983

Electrophoretic mobility profiles of mouse leukemias. II. Electrophoresis of thymic lymphoma, myeloid leukemia and reticulum sarcoma cells.

Electrophoretic mobility of cells from 21 primary mouse leukemias was investigated and compared with that of various normal mouse reference cells. Six thymic lymphomas, nine reticulum cell sarcomas, five myeloid leukemias and one stem-cell leukemia were examined. The mean AEM of cells from the group of primary thymic lymphomas (1.13 microns s-1 V-1 cm) was similar to that of reticulum cell sarcomas (1.15 microns s-1 V-1 cm) and significantly lower than that of the myeloid leukemias (1.20 microns s-1 V-1 cm). Since the examined cell suspensions were prepared from leukemic lymph nodes, the analysis was performed to investigate the possible admixture of normal LNC in the cell populations. Electrophoretograms of normal and leukemic lymph nodes were compared and the AEM of cells from leukemic lymph nodes was considered separately for two cell populations, one corresponding in size to normal LNC (6-9 microns in diameter) and the other to leukemic blast cells (10-16 microns in diameter). In the 6-9 microns cell subpopulations from leukemic lymph nodes, electrophoretically slow cells corresponding to B LNC were almost totally depleted (1%); also electrophoretically fast cells with the mean AEM of T LNC were fewer (45-57%) than in normal LNC populations. The leukemic cells 10-16 microns in diameter displayed mean AEM of 1.09 (thymic lymphomas), 1.12 (reticulum cell sarcomas) and 1.21 (myeloid leukemia) micron s-1 V-1 cm. The mean AEM of blast cells from thymic lymphomas and reticulum cell sarcomas was not significantly different; it was similar to that of blast cells prepared from normal mouse thymus (1.09 microns s-1 V-1 cm) on a density gradient. In contrast, the 10-16 microns cell populations from lymph nodes of mice with myeloid leukemias were significantly faster than blast cells from thymic lymphomas and reticulum cell sarcomas.

Animals↗
PubMed1982

Biological effects of bone-seeking alpha emitters with respect to the risk of internal contamination in man.

Some results of long-term experiments performed in mice contaminated with 226Ra and 239Pu, especially the damage to the hemopoietic system and the incidence of osteosarcoma, are reported. Different degree of damage to the bone marrow hemopoiesis, depending on the arrangement of marrow cavities and the capability of stem cells to produce differentiated progeny are evaluated. This ability decreases with age and with duration of the contamination due to radionuclides. From the above aspects of radiation injury the ability of hemopoiesis to compensate the decreased production of differentiated peripheral cell forms is discussed. It is remarkable that myeloid leukemia occurred earlier and more frequently in 239Pu-contaminated animals than in controls. After the injection of plutonium-239, myeloid and lymphatic leukemias were diagnosed in most of the animals dying without osteosarcoma. These diseases represented a danger not lower than that of osteosarcoma which appeared in average later and the expected incidence of which was estimated to rise linearly with age. The findings are discussed from the aspect of their application in evaluating the risk resulting for man from the incorporated bone-seeking alpha emitters.

Alpha Particles↗
PubMed1982

Some quantitative micromorphological characteristics of granulocytic leukemia in 239Pu-injected mice and untreated controls.

Cytologic and histologic evaluation of granulocytic leukemia was carried out in 22 plutonium-treated mice and in 17 controls. The contaminated animals were injected i. v. with 5.4 kBq 239Pu/mouse (180 kBq/kg) at the age of 70 days. Morphologic evidence of the disease was based on the identification of immature abnormal granulocytes in the bone marrow and spleen and on the histologically ascertained leukemic infiltration at least in one of the tissues examined (liver, lung, kidney, lymph nodes). Whatever further symptoms are thought to be of non-specific value. The leukemic process could be mostly evaluated as more florid in the spleen than in the bone marrow. The less active leukemic proliferation in 239Pu-treated mice than in diseased controls is the most important finding of this study. The results are discussed.

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