Papers by Janos Minarovits
Author response for "Microbiomes in supragingival biofilms and saliva of adolescents with gingivitis and gingival health
Production of citokines by human PBMCs in simulated microgravity
ESASP, Aug 1, 2005
Take and growth of the transplantable MC29 hepatoma in allogeneic and xenogeneic hosts
PubMed, 1984
We report here the unexpected biological behaviour of the transplantable MC29 virus-induced hepat... more We report here the unexpected biological behaviour of the transplantable MC29 virus-induced hepatoma. This neoplasm, originating from an inbred white Leghorn (Duke) chicken, is maintained in our laboratory by serial in vivo passages in Hunnia hybrid chickens allogeneic to the original host. More than 80% of the tumours developing after subcutaneous inoculation of 3 x 10(6) hepatoma cells into newly hatched chickens grew progressively, while after injection of the same number of cells into 7 days old birds regressive tumour growth was observed. Transplantation from the allogeneic hosts into 7 days old inbred white Leghorn (Duke) chickens also resulted in regression of tumours in the great majority of cases. After inoculation to xenogeneic Japanese quails, progressor tumours developed in both two weeks old and adult birds with a dramatic increase of the frequency of liver metastases. Transplantation to another xenogeneic host, the turkey, revealed an age-related resistance similar to that of Hunnia hybrid chickens.
Effect of poly I:C-activated peritoneal cells on the take of transplantable murine tumours
PubMed, 1987
The effect of syngeneic mouse peritoneal cells (PC) on the growth of four different transplantabl... more The effect of syngeneic mouse peritoneal cells (PC) on the growth of four different transplantable tumours was studied in adoptive transfer experiments (Winn's test). PC from unstimulated mice did not influence the growth of a benzpyrene induced fibrosarcoma (BaF1) and a methylcholantrene induced mastocytoma (P815), but significantly enhanced the growth of a spontaneous adenocarcinoma (Sp4) and Lewis lung carcinoma (LL). PC induced by a single injection of thioglycollate did not influence, whereas PC elicited by proteose peptone markedly enhanced the growth of BaF1 fibrosarcoma. The enhancing effect of peptone induced PC was diminished by a single intraperitoneal dose (100 micrograms/mouse) of polyinosinic-polycytidylic acid (poly I:C) given after peptone injection. Transferring PC obtained after a single injection of poly I:C (100 micrograms intraperitoneally) resulted in retardation of growth of BaF1 fibrosarcoma and Sp4 adenocarcinoma or in a marked decrease in their take depending on the PC/tumour cell ratio. The effector cells involved in the protective effect proved to be different, using these two tumour models. Lewis lung carcinoma and P815 mastocytoma proved to be insensitive to poly I:C-stimulated PC.
Proto-onc gene products as differentiation antigens (a review)
PubMed, 1984
Growth of spontaneous BALB/c tumours excised from and retransplanted to autochtonous hosts
PubMed, 1986
Tumours of aged Balb/c mice developed without any conscious experimental interference were excise... more Tumours of aged Balb/c mice developed without any conscious experimental interference were excised and retransplanted to the autochtonous hosts. The autotransplantation resulted in tumour take after a prolonged period of latency or in no take for an extended period of observation (more than 80 days) in 6 out of 19 cases. This can be regarded as a sign of antitumoural resistance, although it seems to be ineffective against development of recidives and metastases or second tumours. The sensitivity of the autotransplantation method in detecting antitumoural resistance was compared to that of the transplantation-excision-retransplantation assay using a benzpyrene induced Balb/c fibrosarcoma; the autotransplantation method proved to be less sensitive. According to these data the existence of some kind of resistance against spontaneous tumour cells cannot be excluded.
The effect of simulated microgravity conditions on the TNF-alpha production by human PBMCS
PubMed, Jul 1, 1999
Our earlier space experiments demonstrated that the interferon production of human lymphocytes in... more Our earlier space experiments demonstrated that the interferon production of human lymphocytes in microgravity is 4-8 times higher than those of the synchronous ground controls in vitro (Talas et al. 1983). These data suggested that the microgravity has a significant effect on cells. Since the possibilities to perform space-experiments are very limited and our study raised many interesting questions, we wished to simulate microgravity conditions in our laboratory. For this reason we purchased a Rotary Cell Culture System (RCCS) equipment to study different cell lines and human peripheral blood mononuclear cells (PBMCs) in experimental microgravity conditions. RCCS is a horizontally rotated bubble free culture vessel with membrane diffusion gas exchange. We report here an analysis of TNF-alpha (tumor necrosis factor-alpha) production by human PBMCs (control cultures exposed to simulated microgravity in RCCS). The cells were incubated in the presence or absence of either NDV (Newcastle Disease Virus) or one of the different forms (PHA-M or -P) of Phytohaemagglutinin.
Mouse peritoneal cells activated with a combination of indomethacin, poly I:C and Syncumar inhibit the take of Lewis lung carcinoma in adoptive transfer assay
PubMed, 1987
Effect of peritoneal cells (PC) from mice treated with a combination of drugs (indomethacin, poly... more Effect of peritoneal cells (PC) from mice treated with a combination of drugs (indomethacin, poly I:C and Syncumar) on the take of Lewis lung (LL) carcinoma was studied in Winn-type adoptive transfer experiments. Transfer of PC from mice given a single intraperitoneal injection of polyinosinic-polycytidylic acid (poly I:C) or indomethacine or Syncumar (100 micrograms of each) per se did not suppress the take of Lewis lung carcinoma in the recipient mice. PC obtained from mice treated with a combination of indomethacin and poly I:C or poly I:C and Syncumar also failed to inhibit the take of the tumour. In contrast, PC collected from mice after a combined treatment with the three drugs (indomethacin + poly I:C + Syncumar) resulted in a 30-60% decrease in tumour take depending on the tumour cell/PC ratio. This effect could not be observed when a single intraperitoneal dose of cyclophosphamide was administered three days before starting of the combined treatment of the donor mice. The effector cells contributing to the tumour inhibitory effect proved to be nonadherent cells, probably large granular lymphocytes (LGL), as their suppressive effect was abrogated after treatment with the lysosomotrop vital dye neutral red.
Characterization of activated peritoneal cells inhibiting the take of transplantable murine tumours
PubMed, 1989
We studied the properties of activated peritoneal cells (PC) inhibiting the take of SP4 spontaneo... more We studied the properties of activated peritoneal cells (PC) inhibiting the take of SP4 spontaneous adenocarcinoma and Lewis lung carcinoma in syngeneic mice. Treatment of the poly I:C activated PC from Balb/c mice suppressing the take of SP4 tumour with anti-asialo GM1 antibody and complement before transfer did not affect their tumour-inhibitory potential. PC from Balb/c nude mice treated with poly I:C also inhibited the take of SP4 tumour. Spleen cells from untreated or poly I:C treated Balb/c and Balb/c nude mice, however, did not inhibit the take of SP4 adenocarcinoma. Treatment of peritoneal cells activated by a combination of poly I:C, indomethacin and Syncumar (referred to as "combined treatment") with anti-asialo GM1 antibody and complement could not, or could only partly abolish their tumour-inhibitory potential. The cells mediating the suppression of the take of Lewis lung tumour proved to be Thy-1,2+/-, Lyt-1-, Lyt 2.2- cells. We conclude that the activated peritoneal cells inhibiting the take of SP4 adenocarcinoma and Lewis lung tumour are different from NK cells, NC cells and LAK cells and represent a distinct antitumoural effector cell population.
Comparison of the effects of peritoneal and spleen cells of syngeneic or allogeneic origin on the take of transplantable murine tumours
PubMed, 1989
We compared the effects of various potential effector cells of syngeneic or allogeneic origin on ... more We compared the effects of various potential effector cells of syngeneic or allogeneic origin on the take of a spontaneous adenocarcinoma (SP4) and Lewis lung (LL) carcinoma. As reported earlier, syngeneic resident (non-activated) peritoneal cells (PC) did not inhibit the take of these tumours. On the contrary, transfer of resident PC from allogeneic donors suppressed the tumour take. Syngeneic and allogeneic PC activated by poly I:C or by a combination of indomethacin, poly I:C and Syncumar ("combined treatment") inhibited the tumour take to a similar extent. Syngeneic spleen cells (from untreated mice or from donors underwent "combined treatment") did not inhibit the take of Lewis lung tumour. Transfer of activated allogeneic spleen cells resulted in a stronger inhibition of tumour take than the transfer of resident allogeneic spleen cells.
Nuclear factor 1 (NF-1) binding sites in the genomes of human oncoviruses: a hypothetic role for reintegrated cellular origins of replication in malignant transformation
Medical Hypotheses, 1988
We have found that genomes of human T cell leukemia-lymphoma virus type I (HTLV-I), BK virus (BKV... more We have found that genomes of human T cell leukemia-lymphoma virus type I (HTLV-I), BK virus (BKV), and a hepatitis B virus (HBV) DNA sequence integrated into DNA of a hepatoma-derived cell line contain binding sites for nuclear factor 1 (NF-1), a cellular protein which binds to adenoviral and putative cellular origins of DNA replication. We suggest that cellular origins of DNA replication acquired by oncoviruses may play a role in malignant transformation after reintegration into the cellular genome by providing new targets for cellular factors initiating DNA replication and by perturbing the temporal order of replication.
[Sequences of human herpes virus type 8 and Epstein-Barr virus in AIDS-related primary central nervous system non-Hodgkin's lymphoma]
PubMed, 1997
Presence of human herpes virus type 8 (HHV8), detected by nested PCR, and expression of Epstein-B... more Presence of human herpes virus type 8 (HHV8), detected by nested PCR, and expression of Epstein-Barr virus (EBV), as assessed by immunochemistry and in situ hybridization, were evaluated in 20 primary non-Hodgkin immunoblastic lymphomas (NHL) of the central nervous system (CNS) from patients who died from AIDS, and in 10 samples of cerebral tissues from patients who died from AIDS, without cerebral lymphoma or Kaposi's sarcoma, as controls. Six lymphomas (30%) contained HHV8 sequences, and 19 (95%) expressed EBV; detection of HHV8 was more frequent in patients with Kaposi's sarcoma, than in other subjects (4/6 versus 2/14). Three (30%) controls contained HHV8 sequences, whereas none expressed EBV. AIDS-related CNS NHL is therefore clearly associated with EBV expression, while the presence of HHV8 appears occasional, probably associated with a low tissue viral load. The high frequency of HHV8 in AIDS-related primary CNS NHL patients with Kaposi's sarcoma suggests that this virus could play a role in the pathogenesis of some cerebral lymphomas.
Enhanced take of spontaneous murine tumors in mice treated with inhibitors of macrophage and/or NK cell function
PubMed, 1989
Both macrophages and NK cells have been suggested to play a role in recognizing and eliminating e... more Both macrophages and NK cells have been suggested to play a role in recognizing and eliminating early, in situ neoplasms. Therefore we studied the effect of inhibitors of macrophage and/or NK cell function on the take of transplantable spontaneous murine tumors in syngeneic mice. The treatment of animals with trypan blue, a selective inhibitor of macrophage function, decreased considerably the period of latency of BSP3 adenocarcinoma; however, it did not increase the take of SP4, SP82 and SP84 adenocarcinomas. The treatment of recipients with neutral red, a selective inhibitor of NK cell function, enhanced the take of SP4 adenocarcinoma. The treatment of mice with agents depressing both macrophage and NK cell function (silica or carrageenan) decreased the both macrophage and NK cell function (silica or carrageenan) decreased the period of latency and/or increased the take of SP4, SP82 and SP84 adenocarcinomas. Carrageenan or a combined treatment with both trypan blue and neutral red also enhanced the take of BaF1, a benzo(a)pyrene-induced fibrosarcoma. We concluded that both macrophages and NK cells may function as effector cells of an antitumoral surveillance system.
[Epstein-Barr virus]
PubMed, Feb 1, 1993
Epstein-Barr virus is an ubiquitous humanpathogenic herpesvirus. It has been identified as the et... more Epstein-Barr virus is an ubiquitous humanpathogenic herpesvirus. It has been identified as the etiologic agent of infectious mononucleosis. In addition it is associated with the cancers nasopharyngeal carcinoma and Burkitt's lymphoma. Like other herpesviruses it infects cells in a lytic way or it persists in a latent state. Classically, the serologic diagnosis of Epstein-Barr virus infections is done by the agglutination of sheep erythrocytes according to Paul and Bunnell as a rapid testing method, and with the immunofluorescence assay. Lately, also the enzyme linked immunosorbent assay using recombinant viral antigens is used for Epstein-Barr virus diagnostics.
Frontiers in Cellular and Infection Microbiology, Dec 22, 2021
Periodontitis is caused by pathogenic subgingival microbial biofilm development and dysbiotic int... more Periodontitis is caused by pathogenic subgingival microbial biofilm development and dysbiotic interactions between host and hosted microbes. A thorough characterization of the subgingival biofilms by deep amplicon sequencing of 121 individual periodontitis pockets of nine patients and whole metagenomic analysis of the saliva microbial community of the same subjects were carried out. Two biofilm sampling methods yielded similar microbial compositions. Taxonomic mapping of all biofilms revealed three distinct microbial clusters. Two clinical diagnostic parameters, probing pocket depth (PPD) and clinical attachment level (CAL), correlated with the cluster mapping. The dysbiotic microbiomes were less diverse than the apparently healthy ones of the same subjects. The most abundant periodontal pathogens were also present in the saliva, although in different representations. The single abundant species Tannerella forsythia was found in the diseased pockets in about 16-17-fold in excess relative to the clinically healthy sulcus, making it suitable as an indicator of periodontitis biofilms. The discrete microbial communities indicate strong selection by the host immune system and allow the design of targeted antibiotic treatment selective against the main periodontal pathogen(s) in the individual patients.
DNA Methylation in Eukaryotes: Regulation and Function
Springer eBooks, 2017
Medical Hypotheses, 1987
The mechanism of action of LAV/HTLV-III resulting in a pronounced cytopathio effect is still unkn... more The mechanism of action of LAV/HTLV-III resulting in a pronounced cytopathio effect is still unknown. YJe demonstrate that the long terminal repeat (LTR) sequence and env gene of LAV/HTLV-III contain regions of 70-80 % homolo and/or complementarity with rcgiona of small nuclear (sz RNAs Ul and U2. On this basis WC hypothesize that the cytotoxic effect of LAV/HTLV-Ii1 ia due-at least partly-to the inhibition of processing of cellular hnRNAs by competing for splice junction aites and/or by complexing with Ul and especially U2 RNAs.
Genome Research, Feb 10, 2009
The natural history of cancers associated with virus exposure is intriguing, since only a minorit... more The natural history of cancers associated with virus exposure is intriguing, since only a minority of human tissues infected with these viruses inevitably progress to cancer. However, the molecular reasons why the infection is controlled or instead progresses to subsequent stages of tumorigenesis are largely unknown. In this article, we provide the first complete DNA methylomes of double-stranded DNA viruses associated with human cancer that might provide important clues to help us understand the described process. Using bisulfite genomic sequencing of multiple clones, we have obtained the DNA methylation status of every CpG dinucleotide in the genome of the Human Papilloma Viruses 16 and 18 and Human Hepatitis B Virus, and in all the transcription start sites of the Epstein-Barr Virus. These viruses are associated with infectious diseases (such as hepatitis B and infectious mononucleosis) and the development of human tumors (cervical, hepatic, and nasopharyngeal cancers, and lymphoma), and are responsible for 1 million deaths worldwide every year. The DNA methylomes presented provide evidence of the dynamic nature of the epigenome in contrast to the genome. We observed that the DNA methylome of these viruses evolves from an unmethylated to a highly methylated genome in association with the progression of the disease, from asymptomatic healthy carriers, through chronically infected tissues and pre-malignant lesions, to the full-blown invasive tumor. The observed DNA methylation changes have a major functional impact on the biological behavior of the viruses.
Magyar Tudomány
Ez a megemlékezés az eminens magyar mikrobiológus, Földes István professzor sokoldalú tudományos ... more Ez a megemlékezés az eminens magyar mikrobiológus, Földes István professzor sokoldalú tudományos munkásságának egyes mozzanatait vázolja fel dióhéjban, születése századik évfordulóján.
Beszámoló. Az oxidatív stressz és a betegségek Országos konferencia Budapest, 2014. november 6–7.... more Beszámoló. Az oxidatív stressz és a betegségek Országos konferencia Budapest, 2014. november 6–7. | Könyvismertetés. Michael Schönberger Glossar der Handchirurgie © Michaela Schnur Verlag, Drezda, 2007 ISBN-10: 3-937890-04-1 ISBN-13: 978-3-937890-04-3 | Dr. Ralovich Béla Adatok a mikrobiológiával kapcsolatos ismeretek oktatás- és kutatástörténetéhez – II. Magánkiadás, Balatonberény, 2014 ISBN: 978-963-08-9753-2 Ára: 49,95 € (~18 700 HUF
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Papers by Janos Minarovits