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Biomedical subjects

L Borecký

Publications and source records attributed to L Borecký.

At least 55 records · Page 3Linked to original sources
PubMed1981

Accelerated appearance of an ascitic tumour after long-term application of interferon to NZB/W mice.

In two similarly designed experiments female NZB/W mice treated with mouse L-cell interferon developed an ascitic tumour when the treatment was begun at 3.5 months of age. But no tumour appeared within a 6 months' observation period when 6 months old mice were used. A transient rise of anti-DNA antibodies preceded the tumour appearance in mice. The ascitic tumour was sensitive to antimetabolites and insensitive, or marginally sensitive, to alkylating agents or interferon. The tumour cells were adapted to growth in suspension in vitro. They caused tumour growth in various inbred and random-bred mouse lines. Attempts to transfer the tumour to Swiss mice with cell free preparations were unsuccessful.

Animals↗
PubMed1980

The cell growth inhibitory and antiviral effects of interferon in cloned transformed mouse cells.

Eight clones and two subclones of SV40- and seven clones and one subclone of 20-methylcholanthrene-transformed C3H mouse embryonic fibroblasts were compared in tests for sensitivity to the antiviral and cell-growth inhibitory activities of a partially purified mouse L-cell interferon. While the sensitivity of clones and subclones to the antiviral activity of interferon was comparable to that of parent lines, the cell-growth inhibitory activity of interferon in the SV40 clones showed more than 100-fold variation and the methylcholanthrene-transformed cells could be divided into two groups in this respect. No correlation of sensitivity to the cell-growth inhibitory effect of interferon with the chromosome number, interferon-producing capacity or tumorigenicity of the clones could be detected. However, the cells of the interferon-sensitive clones No. 36 of the methylcholanthrene-transformed line were destroyed by macrophages at higher percentage binding of 125I-labeled soybean lectin. These results suggest that (1) the cell-growth inhibitory effect of interferon might be mediated by a specific type of receptors, and (2) N-acetyl-galactosamine present on the surface of interferon-resistant cells in a higher concentration than on interferon-sensitive cells hinders the recognition of cells both by macrophages and by interferon.

Animals↗
PubMed1980

Production of interferon and other lymphokines during murine tumour growth. I. Lymphokines in cell--free fluid of rat Zajdela ascites hepatoma.

Cell-free ascites of rat Zajdela hepatoma was assayed for the presence of lymphokine-like factors. Macrophage migration inhibitory and microbial growth inhibitory cytokines were detected with peak activities at day 4-8 and 10-11 after tumour inoculation, respectively. Occasionally, skin reactive activity was found, whereas only borderline titres of an interferon-like substance were demonstrated. Preliminary studies indicated that both migration inhibitory and microbial growth inhibitory factors are proteins resembling the corresponding lymphocyte-derived lymphokines. The cellular site of formation of these factors remains to be determined.

Animals↗
PubMed1980

Production of interferon and other lymphokines during murine tumour growth. II. Induction of an interferon by Ehrlich ascites cells in outbred mice.

A viral inhibitor produced in the peritoneal cavity of outbred Swiss mice inoculated with allogeneic Ehrlich ascites cells was identified as an interferon. It was antigenically related to viral interferons of type 1 and seems to be produced by macrophages. The interferon activity in the peritoneum reached maximal levels at 24 hr after tumour challenge. Interferon induction by Ehrlich ascites cells was not inhibited in lipopolysaccharide-hyporeactive mice. In addition, cell growth inhibition, enhanced interferon production after priming with small doses of this interferon, and increased susceptibility of cells treated with this interferon to the toxic effect of double-stranded RNA was demonstrated.

Animals↗
PubMed1979

Production of antiviral and migration inhibitory activities in the peritoneum of mice after inoculation with allogenic Ehrlich ascites tumor cells.

Peritoneal inoculation of Ehrlich ascites cells into mice stimulates the appearance of migration inhibitory factor (MIF) not only in the peritoneum but also in the circulation of mice. Whereas the MIF-activity in the peritoneum reached maximum at 6 days and disappeared within 17 days, the MIF-activity of sera reached maximum levels at about 11 days after intraperitoneal inoculation of tumor cells (10(6) of EAC per mouse). In addition, an antiviral activity of peritoneal exudates was observed in the early stage (24--72 h) of tumor challenge. The time-course of appearance of both MIF and AV-inhibitor are presented. A significant decrease of MIF-activity was noted when the tumor-inoculated mice were treated with ds-RNA, antithymocyte serum and cyclophosphamide, respectively. The appearance of antiviral activity in the peritoneum of tumor-inoculated mice seems to be macrophage-dependent. Although the antiviral factor meets several criteria of interferons, further studies are required for its characterization.

Animals↗
PubMed1979

Production of human leukocyte interferon for clinical use under immunoelectrophoretic control.

Human leukocyte interferon (HLIF) can be contaminated by several antigens which may include also potentially pathogenic agents. For this reason, gel filtration as a separation method was included into the routine procedure of preparation and purification of HLIF for clinical use. Since production of HLIF requires the cultivation of leukocytes in the presence of serum (or albumin), serum proteins represent then the majority of proteins contaminating IF preparations. Measuring the total protein content, as a control of various antigens present in HLIF preparations during purification, becomes ineffective because, essentially, it indicates only the decrease of the amount of proteins derived from cultivation medium. For a better visualization of dissociation of different antigens from molecules with IF activity during the purification procedure, the method of quantitative immunoelectrophoresis was applied utilizing a sheep antiinterferon serum in assay. Our results indicate that this method represents a valuable control test.

Animals↗
PubMed1979

Antiviral and anticellular effects of interferon on the mouse embryonic cells transformed by viruses and/or chemical carcinogen.

The antiviral and anticellular activity of partially purified mouse interferon has been tested in cell lines transformed with Simian Virus 40 (MEB-SV 40), mouse sarcoma virus (Harvey strain) (MEB-MSV), and 20-methylcholanthrene (MEB-MCH), respectively. The transformed lines were derived from C3H mouse embryonic primary cells. It has been shown that the MEB-MSV cells were 10 to 50 times less sensitive to the antiviral effect of interferon than the MEB-SV 40 or MEB-MCH cells. A 30% reduction of the number of treated cells as compared with untreated control cells was taken as basis for comparison of anticellular activity of interferon in transformed lines. While the MEB-MCH cells required 1000 units of interferon for a 30% growth inhibition, about 3000 units were necessary for a comparable suppression of MEB-SV 40 cells and/or MEB-MSV cells.

Agglutination↗
PubMed1979

The effect of interferon induction on complement level in rat.

Relatively high levels of interferon were achieved in rat sera by intracardial inoculation with Sindbis virus followed 15 min later by intraperitoneal application of dimethylsulfoxide. At intervals when interferon titres reached the maximum, the levels of complement were decreased as compared with the control group of rats. Single administration of dimethylsulfoxide did neither induce interferon nor influence the complement levels in sera of rats of the Dobrá Voda breed tested. Similar results were obtained with concentrated Newcastle disease virus inoculated intraperitoneally. Of interest is the finding that properdin levels seem to increase at the same time as interferon.

Animals↗
PubMed1979

Long-term culture of guinea pig tongue cells: a suitable interferon system.

The interferon system was investigated in a long-term culture of guinea pig tongue (GPT) cells. Interferon synthesis was induced with Newcastle disease virus (B strain) and f2 phage double-stranded RNA. Guinea pig interferons were about 2 times more active in cell cultures established from guinea pig embryos than in the GPT cells. Human leukocyte and mouse peritoneal cell interferons were active in this cell system also.

Animals↗
PubMed1979

Decrease of sensitivity to cell-growth inhibitory effect of interferon in human embryo cells after infection with SV40.

No changes in sensitivity of human embryo cells (HEC) to the antiviral action of interferon early (i.e. up to 17 days) after infection with simian virus 40 (SV40) could be detected. At the same time the sensitivity of cells to the cell-growth inhibitory effect of interferon decreased considerably. The changes in sensitivity of HEC to interferon action occurred during 5 successive passages following the infection with SV40 and remained on a similar level thereafter. During this period, no morphological alterations of cells were observed.

Cell Division↗
PubMed1979

The effect of native and sonicated double-stranded polyribonucleotides on the course of spontaneous autoimmune disease in NZB and NZB/Swiss F1 mice.

The administration of sonicated fractions of f2 phage polyribonucleotides caused an increased weight loss and deterioration of the clinical state in female NZB mice. Discontinuance of the treatment resulted in an improvement of both the clinical state and the genetically determined autoimmune disorders of these mice. Some potential explanations of this effect are discussed.

Animals↗
PubMed1978

Quantitative immunoelectrophoresis of human interferon. A new approach to characterization of interferon preparations.

The electroimmunoassay (quantitative "rocket" immunoelectrophoresis) method was adopted for analysis and characterization of interferon preparations. Ammonium sulphate-precipitated anti-interferon globulin also containing unknown antibodies against antigens that contaminate interferon preparations was used in the tests. By comparing the results of the electroimmunoassay of fractions obtained by polyacrylamide gel electrophoresis of human leukocyte interferon with the antiviral activity of the fractions, an excellent dissociation of molecules with interferon activity from the bulk of contaminating antigens was achieved. The method is extremely sensitive and requires very small volumes for assay.

Electrophoresis, Polyacrylamide Gel↗