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Biomedical subjects

M Bencsáth

Publications and source records attributed to M Bencsáth.

16 recordsLinked to original sources
PubMed2002

Murine and human hematopoietic colony formation: a possible regulatory role for intracellular histamine.

Increasing number of data suggests that locally produced histamine is involved in regulation of hematopoiesis. In this study the granulocyte/macrophage (CFU-GM) colony formation by normal murine or human bone marrow cells, leukaemic colony formation (CFU-L) by a murine leukemia cell line (WEHI 3B), and colony formation by bone marrow cells from patients with chronic myeloid leukemia (CML) have been examined. We detected mRNA and protein expression of histidine decarboxylase (HDC), the only enzyme responsible for histamine synthesis both in normal bone marrow progenitor cells and in leukaemic progenitors. The significance of in situ generated histamine was shown on colony formation by inhibitory action of alphaFMH (blocking HDC activity, i.e. de novo histamine formation) and by N,N-diethyl-2-[4-(phenylmethyl)phenoxy]-ethanamine-HCl (DPPE) disturbing the interference of histamine with intracellular binding sites. These data provide further confirmation of the role of histamine in development and colony formation of bone marrow derived cells.

Animals↗
PubMed2000

[Secondary cutaneous infiltration in B-cell chronic lymphocytic leukemia (B-CLL)].

Authors report here on a case presenting as B-CLL and complicated with cutaneous infiltration involving the legs and the trunk a year later. Immunohistochemic analysis and the immunoglobulin heavy chain gene rearrangement confirmed cell invasion into the skin identical with the underlying disorder. After failure of conventional chemotherapy, interferon alpha 2b therapy has been started with satisfactory result. Few cases presenting cutaneous infiltration in the course of B-CLL has already been reported in the literature. Secondary cutaneous B-cell lymphoma represents an entity of the poorest prognosis in comparison with primary cutaneous form treated with conventional therapy as well as with lymphomas lacking skin manifestations. Interferon alpha 2b therapy cleans up the skin and yields a favourable survival so it's introduction recommended in this entity. Authors summarise the characteristics of secondary cutaneous B-cell lymphomas on the basis of literature survey. According to authors investigations histidine decarboxylase activity was found to be absent from the lymphocytes infiltrating the skin in contrast to those remaining in the circulation. This seems to be a newly recognised feature of these cells. The changing character of the disease raises the possibility of an altered gene expression pattern of the cells invading the skin. Authors summarise data from the literature concerning suspected molecular mechanism of tissue invasion.

Antineoplastic Agents↗
PubMed2000

Histidine decarboxylase expression in human melanoma.

Histamine has been implicated as one of the mediators involved in regulation of proliferation in both normal and neoplastic tissues. Histidine decarboxylase, the only enzyme that catalyzes the formation of histamine from L-histidine, is an essential regulator of histamine levels. In this study, we investigated the gene and protein expression of histidine decarboxylase in melanoma. Reverse transcriptase polymerase chain reaction and in situ hybridization studies of WM-35, WM-983/B, HT-168, and M1 human melanoma cell lines both resulted in positive signals for histidine decarboxylase messenger RNA. A polyclonal chicken antibody was developed against human histidine decarboxylase and protein expression was confirmed by western blot analysis of the cell lysates, revealing a predominant immunoreactive band at approximately 54 kDa corresponding to monomeric histidine decarboxylase. Protein expression of histidine decarboxylase was also shown by flow cytometric analysis and strong punctate cytoplasmic staining of melanoma cell lines. Moreover, both primary and metastatic human melanoma tissues were brightly stained for histidine decarboxylase. When compared with the very weak or no reactions on cultivated human melanocytes both western blot and immunohistochemical studies showed much stronger histidine decarboxylase expression in melanoma cells. These findings suggest that expression of histidine decarboxylase is elevated in human melanoma.

Blotting, Western↗
PubMed2000

Secondary cutaneous infiltration in B cell chronic lymphocytic leukemia.

We describe a patient presenting with B cell chronic lymphocytic leukemia (B-CLL) who subsequently developed cutaneous infiltrates. Specimens of the blood, bone marrow and cutaneous infiltrations all showed the same heavy-chain gene rearrangement. Following failure of conventional chemotherapy, and in view of the similarity of the disease to cutaneous T cell lymphoma, interferon-alpha therapy was employed with satisfactory results. Introduction of this cytokine to the therapeutic modalities for secondary cutaneous B-CLL would hopefully change the poor outcome of this entity, or at least could produce a better quality of life. Loss of histidine decarboxylase activity in the infiltrating cells - in contrast to circulating lymphocytes - may be associated with the transformation of B-CLL to a more aggressive infiltrative form, offering a possible explanation for tissue invasiveness. The changing character of the disease raises the possibility of a second mutational event in the course of B-CLL.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Histidine decarboxylase in peripheral lymphocytes of healthy individuals and chronic lymphoid leukemia patients.

Histidine decarboxylase (HDC), the only enzyme capable of synthetizing histamine, has been found in many proliferating cells and tissues suggesting a role of histamine in cellular proliferation. In this study expression of HDC and the significance of histamine in the proliferation of peripheral lymphocytes of five healthy persons and six patients with chronic lymphoid leukemia (CLL) was examined. Expression of HDC mRNA and the protein was proved by reverse transcriptase polymerase chain reaction and by immunoblot, respectively. The role of histamine was studied in proliferation assays in the presence of irreversible inhibitor of the HDC (alpha-fluoromethylhistidine--aFMH) and also by competing for the intracellular binding sites of histamine using N,N-diethyl-2, 4-phenylmethyl-phenoxy-ethanamine-HCl (DPPE). By inhibiting the HDC enzyme activity by FMH and blocking the intracellular action of histamine by DPPE, a significant decrease in cell proliferation was observed in mitogen stimulated lymphocytes of healthy donors. In CLL patients the proliferation of leukemic lymphocytes was significantly inhibited by blocking the binding of histamine to intracellular binding sites by DPPE but not by FMH inhibiting only the de novo histamine formation. The observations suggest that HDC has functional relevance in lymphocytes, since mitogen induced lymphocyte proliferation of healthy donors is mainly enhanced by de novo synthesis and subsequent action of intracellular histamine. Alternatively, in constitutively proliferating chronic lymphoid leukemia cells we suggest that the preformed pool but not the de novo synthesized intracellular histamine interferes with cellular proliferation.

Cells, Cultured↗
PubMed1994

Secretory response of Tetrahymena to insulin: the influence of electric pulses.

The secretion of the enzyme hexosaminidase (HA) by Tetrahymena pyriformis, T. thermophila and T. thermophila mutant (MS1) cells was studied on the action of insulin or insulin in combination with electric pulses. The three species of Tetrahymena responded by different rates of enzyme activity. Following insulin or insulin + electrical pulses, the daughter cells of T. pyriformis manifested similar effects 24 h later by elevating the extracellular HA level, being higher when electrical pulses were included in the action on the parental cells. Insulin combined with electric pulses gave higher inter-strain differences in the reaction of Tetrahymena as reflected by HA enzyme measurements. MS1 cells lacking the capacity to release lysosomal enzymes when exposed to insulin with electric stimulation elicited a high level of HA released.

Animals↗
PubMed1993

The effect of an electric field on the release of hexosaminidase in Tetrahymena.

The activity of beta-D-hexosaminidase was detected by spectrofluorometry in the growth media of three species of Tetrahymena. The enzyme activity was about six times higher in T. pyriformis compared with the wild cells of T. thermophila, while the MS-1 mutant of T. thermophila manifested very low enzyme activity under the same experimental conditions. An electric field and electrical pulses produced significant though different increases in enzyme activity in media of wild and mutant T. thermophila. In contrast, T. pyriformis responded to the field pulses by decreasing the activity of the enzymes detected in the growth media.

Animals↗
PubMed1984

Further studies on the biochemical characterization of the MC-29 virus derived transplantable hepatoma (VTH). I. Binding of 3H-cortisol to cytoplasmic receptor and DNA.

The molecular mechanisms underlying the failure of steroids to stimulate glucose-6-Pase and arylhydrocarbonhydroxylase activities in the MC-29-virus-derived transplantable hepatoma (VTH) were investigated. Following cellular uptake of 3H-Cortisol, its subcellular distribution, binding to a specific cytoplasmic receptor and the interaction between steroid-bound receptor and DNA were compared in VTH and in normal chicken liver. No appreciable difference was observed either in 3H-Cortisol uptake or in binding to cytoplasmic receptors. However, compared with normal liver, only half as much hepatoma steroid receptor was able to interact with DNA at the protein/DNA ratio of 60. This reduced DNA binding of VTH 3H-Cortisol-receptor was irrespective of the source of DNA (VTH or liver). It is concluded that one of the causes for abnormal gene regulation in VTH may lie at the level of DNA-protein interaction.

Animals↗
PubMed1982

HBsAg-like structures in immunosuppressed mice inoculated with human hepatitis B virus.

Thymectomised and irradiated DBA/2 mice were injected intraperitoneally with human serum containing high titer of HBsAg, and were positive for HBsAg. Through the entire experiment neither degenerative and inflammatory lesions nor hepatitis B virus antigens could be detected in the liver of these animals by histomorphology and immunofluorescence, respectively. The sera of all these mice were negative for HBsAg by radioimmunoassay. By electron microscopy, however, increasing amounts of filaments and round particles measuring 20-22 nm in diameter could be observed in the endoplasmic reticulum of the mouse hepatocytes from the 8th day following injection. From the 90th day after inoculation the number of the filaments increased in an extreme degree. After fixation with KMnO4 and EDTA preferential staining, the filaments proved to be highly electrondense. According to the authors the filaments observed in mouse livers are lipoproteins produced by the hepatocytes in response to HBV inoculation. The appearance of the filaments is HBsAg-like, though their immunological characteristics become modified.

Animals↗
PubMed1982

DNA polymerase and thymidine kinase activities in MC-29 virus-induced transplantable hepatoma and the effect of cytostatic treatment of these activities.

The activity of DNA polymerases and thymidine kinase was compared in the MC-29 leukosis virus-induced transplantable hepatoma and in the livers of rats treated with cyclophosphamide (CP), cytosine-arabinoside (ara-C) and 5-fluoro-uracil (5-FU). The specific activity of DNA polymerase was twenty times greater in the MC-29 leukosis virus-induced hepatoma, while thymidine kinase was only 3-5 times greater than in liver. All three enzymes showed Michaelis-Menten kinetics in their substrate and template saturation curves. The template utilization of DNA polymerases from hepatoma and from liver was compared. Both had higher activities on a poly(dA) . poly(dT) template at pH 8.0, than on DNA at pH 7.5. After chromatography on a phosphocellulose column two polymerases were separated. The first peak eluted by 0.15 m KCl preferred DNA as template (polymerase alpha). The second eluted by 0.5 M KCl worked better on poly(dA) . poly(dT) (polymerase beta). Thymidine kinase was eluted by 0.25 m KCl. Inhibition by N-ethylmaleimide (NEM) showed the polymerase alpha to be sensitive and the polymerase beta to be resistant to the sulfhydryl blocking agent; similar to the respective enzymes of other eukaryotic cells. The specific activity of DNA polymerase decreased after CP treatment at 6 h and 72 h and after ara-C treatment at 72 h. The specific activities of thymidine kinase were not changed significantly in response to the drug administrations.

Animals↗
PubMed1981

Cytochemical characterization of hepatitis B virus infected liver cells in chronic liver diseases.

The cytochemical characteristics of the hepatitis B virus (HBV) components, the nuclei and cytoplasm of the infected cells were studied in liver needle biopsy material obtained from patients suffering from serologically HBsAg positive chronic hepatitis. The HBV surface and core components were found to be more resistant to proteolytic enzymes and phospholipase than the other cellular components, and only combined digestion was effective. With preferential RNP and specific DNP staining the accumulation of granules 10-20 nm and 20-40 nm in diameter could be observed in the liver cell nuclei. The cytochemical-morphological polymorphism of the latter was well detectable. Part of the granules corresponded to accumulated perichromatin granules. It is assumed that the groups of granules 20-40 nm in diameter, showing a varying density on DNP staining, similar to the chromatin on RNP staining, and not surrounded by a peripheral area represents one of the forms of appearance of the HB virus core component.

Cell Nucleus↗
PubMed1980

Cytochemical study of peritoneal macrophages in carrageenan-treated immunosuppressed mice.

In our examinations the cytochemical characters of the peritoneal macrophages of immunosuppressed mice (Is-PM) were studied. It was stated that the acid phosphatase activity of their lysosomal system decreased in comparison to control cells (N-PM). In Is-PM cells the polyanion content of the cell-coat and the expression of their ConA receptors decreased, while the glycos- and galactosaminoglycan (GAG) content showed a decrease on the surface of every cell of the population. On the first day following carrageenan treatment, acid phosphatase activity of the cells was very low, the GAG content and the conA receptors of the cell-coat disappeared. The characteristic lysosomal alterations could still be observed on the 6th day after treatment. On the basis of our observations treatment with carrageenan impaired not only the lysosomal system of macrophages, but the cell surface too. These cytochemical changes may explain the dramatic decrease in macrophage function observed in carrageenan treatment.

Acid Phosphatase↗
PubMed1978

[Current data on toluene toxicity based on liver biopsy studies].

Authors in 1968 performing the periodoc observation of persons, working in toluene-containing athmosphera noticed the presence of hepatomegaly. Laboratory tests performed in 1968--1976 have revealed increase of the level of GOT. At 22 workers out of 170 liver biopsy was performed. By electron microscopy pathologic alterations in the mitochondria and in the rough-surfaced endoplasmic reticulum could be observed, -since these organella contain the two-third of the GOT of hepatocytes. It is assumed that mitochondria as sources of energy take part in the process of the oxydation of toulene, ribosomes of the rough-surfaced endoplasmic reticulum in the conjugation of benzoic-acid with glycine. Authors assume that there is a correlation between the damage of the organella and the detoxication of the toluene by hepatocytes.

Air Pollutants, Occupational↗