Biomedical subjects

P Kovács

Publications and source records attributed to P Kovács.

At least 19 recordsLinked to original sources

PubMed2006

In vitro effect of biogenic amines on the hormone content of immune cells of the peritoneal fluid and thymus. Is there a hormonal network inside the immune system?

Immune cells contain different hormones and hormone-like molecules, such as insulin, endorphin, triiodothyronine (T3) histamine, serotonin. In earlier in vitro experiments insulin down-regulated histamine, serotonin and T3 content of thymus cells. Now we studied the effect of biogenic amines on the endorphin, T3, serotonin and histamine content of rat peritoneal and thymic cells. Cells were obtained from male rats of 100g body weight. 100 ng/ml serotonin or 300 ng/ml histamine was added for 30 min. After that the cells were prepared for flow cytometric analysis with antibodies to endorphin, T3, histamine and serotonin as primary antibodies and anti-rabbit IgG as secondary antibody. Finishing the measurements the cells were also studied by confocal microscopy. T3 concentration (binding of anti-T3 antibody) increased in peritoneal mast cells after serotonin treatment and in the monocyte-macrophage-granulocyte group after histamine treatment. Thymocytes' T3 content radically decreased after both treatments. Serotonin and histamine treatment also radically reduced the amine content of each other. Endorphin level was resistant to hormonal treatments. The results call attention to a possible hormonal network inside the immune system in which hormones produced by the immune cells themselves can influence each other.

Animals↗

PubMed2006

How does the unicellular Tetrahymena utilise the hormones that it produces? Paying a visit to the realm of atto-and zeptomolar concentrations.

Changes in the hormone content of Tetrahymena pyriformis GL were investigated during histamine, serotonin or insulin treatment at concentrations of 10(-6)M to 10(-21)M for 30 min. The immunologically demonstrable hormone content was studied by using specific antibodies, flow cytometry and confocal microscopy. Histamine at the higher ranges elevated the serotonin content of Tetrahymena, whereas serotonin at the lower ranges (down to 10(-21)M) decreased its histamine levels. Insulin did not affect its serotonin content, whereas serotonin increased its insulin content at each concentration studied (down to 10(-21)M). Insulin between 10(-6)M and 10(-21)M increased the histamine levels of Tetrahymena, although histamine influenced its insulin level only at 10(-6)M. Our results call attention to the presence of hormonal interactions even at "low" levels of phylogeny and to the extreme sensitivity of the hormone receptors of Tetrahymena. These data might explain (1) the requirement of Tetrahymena for (vertebrate) hormone production and hormone receptors and (2) the way that it uses these hormones under natural conditions.

Animals↗

PubMed2006

Perinuclear localization of biogenic amines (serotonin and histamine) in rat immune cells.

EDAC fixation, which polymerizes biogenic amines, and clorgyline, which blocks monoamine oxydase, were used to demonstrate the perinuclear and nuclear localization of histamine and serotonin (5-HT) of immune cells in rat peritoneal fluid and thymus. For detection, an immunocytochemical method combined with confocal microscopy was used. In peritoneal cells (lymphocytes) 5-HT formed spots around the nucleus, while histamine was localized diffusely. In thymocytes, 5-HT was distributed in patches, while histamine formed a garland around the nuclear envelope. Clorgyline enhanced the fluorescence and increased the number of fluorescent positive cells only for histamine, and then histamine-positive nuclei were also present. The results show that: (1) EDAC fixation demonstrates the presence of biogenic amines in immune cells, (2) using this fixation, the perinuclear localization of biogenic amines can be demonstrated, (3) the localization of the two amines is different and (4) the nuclear localization of histamine in thymocytes can be surmised and in mast cells (described previously) is proven again. The potential importance of the nuclear and near-nuclear localization of biogenic amines is discussed.

Animals↗

PubMed2006

Effects of extremely low concentrations of hormones on the insulin binding of Tetrahymena.

FITC-insulin binding to previously hormone-treated Tetrahymena was studied by flow cytometry and confocal microscopy. Hormones produced by Tetrahymena were chosen for study and the hormone concentrations were administered between 10(-6) and 10(-21)M for 30 min. Endorphin, serotonin and insulin significantly reduced the hormone binding however histamine did not influence it at all. Endorphin, serotonin and insulin were significantly effective down to 10(-18)M and the effect of insulin and endorphin suggest a similar mechanism. The results call attention to the efficacy of very low hormone concentrations, which can influence the hormone content (earlier experiments) and receptor binding capacity (present study) of a unicellular organism. This seems to be very important, as in wild (natural) conditions the dilution of signaling materials secreted by a water-living protozoan is very high. In addition, the results point to the selectivity of response, as not all of the hormones that deeply influence other physiological indices (e.g. histamine) have an effect on insulin content or insulin receptors.

Animals↗

PubMed2006

Influence of paraformaldehyde and EDAC fixation on the demonstrability of hormones (histamine, endorphin, triiodothyronine) in rat immune cells: an immunocytochemical comparative analysis.

The amount and localization of three hormones (histamine, endorphin and triiodothyronine [T(3)]) was measured in male and female rat peritoneal cells (lymphocytes, mast cells, monocyte-macrophage-granulocyte group [mo-gran]) using flow cytometry as well as confocal microscopy after paraformaldehyde (PFA) or EDAC fixation. In the EDAC fixed lymphocytes and mo-gran of female animals two-magnitude higher levels of histamine were measured after EDAC fixation and one magitude higher in mast cells. The amount of T(3) was almost four-fold in lymphocytes and 2.5-4-fold in mast cells and mo-gran. Endorphin content was not altered by the type of fixation. In each cell type in males one magnitude higher levels of histamine and T(3) were measured after EDAC fixation and a small, but significant, elevation of endorphin. Confocal microscopy supports the quantitative data. The results show that (1) the fixation with the crosslinking molecule, EDAC, is more suitable for immunocytochemical studies of amino-acid type hormones in immune cells, (2) more histamine and T(3) are present in the immune cells than it was supposed previously when studying PFA-fixed preparations, (3) the estimation of the amount of peptide hormones seems to be accurate after PFA fixation, (4) there is a quantitative difference comparing the results of PFA and EDAC fixation between males and females.

Animals↗

PubMed2006

EDAC fixation increases the demonstrability of biogenic amines in the unicellular Tetrahymena: a flow cytometric and confocal microscopic comparative analysis.

Earlier experiments demonstrated the presence of hormones of the higher ranked animals in Tetrahymena. In the present experiments two fixatives, paraformaldehyde, which is commonly used and a carbodiimide, EDAC that was recommended by Panula et al. for the immunocytochemistry of histamine, are compared in Tetrahymena for the demonstration of histamine and serotonin by using flow cytometry and confocal microscopy. Both hormone levels were significantly higher after EDAC fixation; serotonin almost doubled and histamine was more than fivefold. The confocal microscopic pictures were clearer and the hormones' localization was easier. The results support earlier observations on the presence of these hormones in Tetrahymena and points to the advantage of EDAC fixation for demonstrating these hormones immunocytochemically.

Animals↗

PubMed2006

Influence of in vitro and in vivo insulin treatment on the hormone (histamine, serotonin, endorphin and triiodothyronine) content of thymus and spleen cells.

Thymic and spleen cells were treated in vitro or in vivo with insulin. The in vitro treatments were done with 10(-6), 10(-9), 10(-12) and 10(-15) M concentrations for 30 min and after that histamine, serotonin, endorphin and triiodothyronine (T3) content of the cells were detected by using antibodies to the hormones and flow cytometry as well as confocal microscopy. For in vivo treatment 1 IU/kg insulin was given for adult rats and 1 h after that the target hormone contents were determined by the same manner. Histamine and T3 content radically decreased in the thymus after in vitro treatment independent on the insulin concentrations administered. In vivo treatment halved histamine and T3 content. Serotonin content also decreased after in vitro treatment with the two higher concentrations, however the in vivo treatment did not cause a change. Histamine content was elevated after in vitro treatment in the spleen, independent on the insulin concentration. Endorphin level was not influenced at all. The experiments demonstrate that insulin is a factor which regulates the content (production, storage, secretion?) of some immunologically important molecules of the immune cells. Since each hormone molecule studied has important immunomodulatory role, the experiment points to the indirect immunomodulatory role of insulin.

Animals↗

PubMed2006

Comparison of the binding of anti-tubulin antibody and the fluorescent taxol derivative Flutax-1 to the microtubular system of Tetrahymena.

Using confocal microscopic analysis, FITC-labelled anti-alpha-tubulin antibody and the fluorescent taxol derivative Flutax-1 in fixed and living Tetrahymena pyriformis GL, longitudinal microtubules, oral and somatic cilia, deep fibers, and contractile vacuole pores were equally labeled. While the antibody stained transversal microtubules, these were not labeled by Flutax-1. At the same time, oral cilia were more intensely stained by Flutax-1, than by the antibody. There were no differences in the staining of fixed preparations and living cells. The observations suggest (i) the difference between the MAPs of longitudinal and transversal microtubules which allow or inhibit the binding of the indicator molecules, and (ii) the different functions of these two types of microtubules.

Animals↗

PubMed2006

Influence of the N-acetylation polymorphism on the metabolism of talampanel: an investigation in fasted and fed subjects genotyped for NAT2 variants.

Talampanel is a 2,3-benzodiazepine-type allosteric (noncompetitive) AMPA-antagonist currently being developed as an orally active, broad-spectrum anticonvulsant. Here, a detailed study of its N-acetylation in humans is presented using plasma concentration data of both TLP and its N-acetyl metabolite obtained from healthy volunteers (n = 28) genotyped for N-acetyltansferase NAT2 isozymes. Plasma samples were obtained for up to 48 h after a single oral dose of 75 mg TLP both in fasted and in fed subjects. A perfect correspondence could be established between the phenotype inferred before the study from genotyping and that determined after the study by using plasma metabolite-to-parent molar ratios confirming that this route of metabolism is indeed mediated by NAT2. Analysis of the data has been performed using both noncompartmental analysis and a custom-built, unified parent-metabolite PK model, which incorporates three different acetylation rates according to the genotype-based classification of each subject as slow, intermediate, or fast acetylator to simultaneously fit plasma levels for both TLP and its metabolite. This suggest that for TLP in humans, (i) N-acetylation represents only a relatively small fraction of its total elimination (about one-fourth in fast acetylators and much less in slow acetylators), (ii) acetylation is about eight-twelve times faster in fast and three-six times faster in intermediate acetylators than in slow acetylators, and (iii) the N-acetyl metabolite is eliminated faster than the parent TLP.

Acetylation↗

PubMed2005

[Relative bioavailability of an optimised galenical formulation of mefloquine].

The bioequivalence of an optimised formulation of a generic mefloquine (Mephaquin Lactabs/Test) compared to the reference product under fed conditions was assessed in a GCP/ICH conformable study. A standard two-way randomised crossover design with a 9 week washout period between treatments was used. Blood samples for determination of mefloquine concentrations for calculation of Cmax and AUC were collected at pre-dose and at predefined intervals up to 2016 hours after administration of a single oral dose of 750 mg. A standard bioequivalence analysis was performed on the two one-sided t-test procedure for log-transformed Cmax and AUC. 90% confidence intervals were calculated for both parameters and evaluated against regulatory standards of 80-125% (T/R). Analysis of plasma for mefloquine concentration was performed using a validated LC/MS method with MS detection. The ratio of mean AUC and Cmax (T/R) was 1.015 and 1.044, respectively. The 90% confidence intervals were 95.8-109.3% for AUC and 98.2-110.5% for Cmax. Mephaquin produces plasma concentrations comparable to those after administration of the reference product. The 90% confidence intervals for AUC and Cmax are within the acceptable ranges for bioequivalence of 80-125%. Thus, the optimised galenical formulation of Mephaquin Lactabs is bioequivalent to the reference product.

Administration, Oral↗

PubMed2005

Effect of the inhibition of triiodothyronine (T3) production by thiamazole on the T3 and serotonin content of immune cells.

Triiodothyronine (T3) and serotonin are present in the cells of immune system (blood, peritoneal and thymic lymphocytes, monocytes and granulocytes of the blood and peritoneal fluid, mast cells). In the present experiments the effect of thiamazole, an antithyroid drug was studied on the content of these two hormones in immune cells after one and two weeks of continuous treatment (by drinking water, containing 30 mg/100 ml thiamazole, ad libitum) in adult male rats, using flow cytometric and confocal microscopic analysis. In thymic lymphocytes both hormone contents significantly increased in both time points. A significant decrease of T3 was observed in peritoneal monocytes and granulocytes also in both time points, in peritoneal mast cells after one week and in blood lymphocytes after two weeks. Serotonin content in addition to the elevated thymic values (in both measurements) was significantly reduced in blood lymphocytes after two weeks. Confocal microscopy demonstrated heterogeneous cell populations with disparate hormone content and mostly diffuse localization The experiments call attention to the presence of T3 in the immune cells and to its variable concentration under the effect of a thyrostatic drug as well, as to the T3-serotonin relationship in the cells of the immune system.

Animals↗

PubMed2005

Alcohol consumption during gestation reduces the histamine and triiodothyronine content of rat immune cells.

OBJECTIVE: Different factors acting during pregnancy can cause non-morphological alterations of cells which are manifested later, in adulthood. We studied the effect of maternal alcohol consumption for one day in early pregnancy on the hormone content of immune cells in the adult rat. METHODS: Lactating dams were given 15% ethanol in the drinking water for 24 h on the 3rd day post partum, exposing their pups to ethanol in the breast milk. Some of the same dams had been successfully mated on the day of delivery, so that they were also 3 days pregnant on the treatment day, exposing embryos to alcohol on the third day of pregnancy. In 4 month old pups histamine and triiodothyronine (T(3)) content of citrate elicited peritoneal immune cells (lymphocytes, monocyte-macrophage-granulocyte group, mast cells) as well as thymic cells were determined by flow cytometry and confocal microscopy using specific antibodies. RESULTS: Alcohol treatment during pregnancy decreased highly significantly the content of both hormones in peritoneal cells of the 4 month old adult animals while it was ineffective by breast feeding after birth. Thymic cells did not show any changes. CONCLUSION: Since the immune system had not developed at the time of treatment (3rd day of pregnancy), stem cells were presumably imprinted. Our results indicate the deleterious effects of early maternal alcohol consumption on the hormone content of the immune system.

Alcohol Drinking↗

PubMed2005

Hormonal interactions in Tetrahymena: effect of hormones on levels of epidermal growth factor (EGF).

Tetrahymena pyriformiswas treated with insulin, histamine or serotonin for 30 min and epidermal growth factor (EGF) level was studied inside the cells using specific antibodies and flow cytometry as well as confocal microscopy. The EGF concentration was highly significantly elevated after hormone treatment, regardless of the hormone used. EGF was localized mainly in the cortical region (mucocysts) and in vesicles and this localization did not differ in untreated and treated cells. The results call attention to the possibility of interactions between hormones at unicellular level and points to the presence of a hormonal system in Tetrahymena that includes receptors, hormones and signal transduction pathways as well as hormonal interactions. This could be the basis of further evolution to the hormonal system of multicellulars.

Animals↗

PubMed2005

Presence of hormones (triiodothyronine, serotonin and histamine) in the immune cells of newborn rats.

Five hormones in lymphatic cells from the spleen and thymus of newborn rats were measured using flow cytometry and confocal microscopic immunofluorescence. Immunoreactive histamine, serotonin and triiodothyronine (T(3)) were present in the cells. However, growth hormone and insulin were not observed, except for low levels of insulin in a few spleen cells. Serotonin content was modest compared to the histamine and T(3) levels. The localization of each hormone in the cells was different. The importance of these observations in the light of functional data is discussed.

Animals↗

PubMed2005

Prolonged effect of stress (water and food deprivation) at weaning or in adult age on the triiodothyronine and histamine content of immune cells.

We used two days of total water and food deprivation as stress for female rats at weaning (three weeks old) and at adult age (two and a half months old). Triiodothyronine (T3) and histamine content of immune cells (lymphocytes, mast cells and monocyte-macrophage-granulocyte group in peritoneal fluid; lymphocytes, granulocytes and monocytes in blood; and lymphocytes in thymus) were studied three weeks after stress application using specific antibodies for flow cytometry and confocal microscopy. The stress at weaning increased T3 content of thymus lymphocytes. In case of adult T3, there was a cell type independent significant effect of stress, decreasing values in peritoneal fluid and slightly increasing effect in the blood. Histamine content of granulocytes was also significantly elevated. The experiments demonstrate that not only fetal or neonatal stress has long-lasting consequences, but also stress events in later periods of life in cells (organs) that are continuously differentiating. We will go on to discuss the importance of T3 and histamine in connection with stress and immunity.

Animals↗

PubMed2005

Intracytoplasmic sperm injection with motile and immotile frozen-thawed testicular spermatozoa (the Hungarian experience).

The authors summarize their experience in 75 in vitro fertilization cycles, where frozen-thawed testicular spermatozoa were used for intracytoplasmic sperm injection. In 32 cases, motile spermatozoa could be observed in the frozen-thawed sample. In 34 cases, motility could be induced by pentoxifylline and in nine cases immotile spermatozoa, selected with hypoosmotic swelling test, were used for fertilization. The fertilization rates obtained with motile and immotile spermatozoa (66.1% versus 52.3%) were not significantly different. Our data demonstrate that freezing of testicular spermatozoa opened new possibilities for the treatment of azoospermic men. The clinical pregnancy rate per embryo transfer (ET) (21.87%) was comparable with previous results use of fresh testicular spermatozoa (27.7%). The quality and number of transferred embryos had the most significant impact on the pregnancy rate. The fertilization rate and frequency distribution of good-quality embryos were lower in the case of immotile spermatozoa, and pregnancies were only achieved when motile spermatozoa had been used.

Adult↗

PubMed2004

Mapping of genetic determinants of the sympathoneural response to stress.

Activation of the sympathoadrenal system (SAS, comprising the sympathetic nervous system and the adrenal medulla) in response to stressful stimuli is an important defense mechanism as well as a contributor to several cardiovascular diseases. There is variability in the SAS response to stress, although the extent to which this is genetically regulated is unclear. Some rodent models, including the hereditary hypertriglyceridemic (hHTg) rat, are hyperresponsive to stress. We investigated whether quantitative trait loci (QTLs) that affect sympathoadrenal response to stress could be identified. Second filial generation rats (n = 189) derived from a cross of the hHTg rat and the Brown Norway rat had plasma norepinephrine (NE) and epinephrine (Epi) levels, indices of activation of the sympathoneural and adrenal medulla components, respectively, measured in the resting state and in response to an immobilization stress. Responses were assessed early (20 min) and late (120 min) after the application of the stress. A genome scan was conducted using 153 microsatellite markers. Two QTLs (maximum peak LOD scores of 4.17 and 3.52, respectively) influencing both the early and late plasma NE response to stress were found on chromosome 10. Together, the QTLs accounted for approximately 20% of the total variation in both the early and late NE responses in the F(2) rats. Interestingly, the QTLs had no effect on plasma Epi response to stress. These findings provide evidence for a genetic determination of the response of a specific component of the SAS response to stress. Genetically determined variation in sympathetic nervous system response to stress may contribute to cardiovascular diseases.

Animals↗

PubMed2004

Prolonged impact of five imprinters on the serotonin content of white blood cells and mast cells of weanling rats: outstanding effect of benzpyrene and chlorpheniramine.

In previous experiments, treatment at weaning or adult age with endorphin, serotonin or an antihistamine (late hormonal imprinting) durably influenced the serotonin content of white blood cells and mast cells of rat. In the present experiments, five molecule (approved imprinters in other indexes) were studied for imprinting effect of immune cells, 3 weeks after a single treatment at weaning. Three steroid hormone-like molecule (vitamin D3, mifepristone and dexamethasone) were ineffective (except dexamethasone in 1/4 indexes), while benzpyrene (aromatic hydrocarbon) and chlorpheniramine (H1-receptor blocker antihistamine) were highly effective (5/6 and 4/4 respectively). The results indicate: (1) a prolonged (late imprinting) effect of a single treatment with certain molecules acting at receptor level; (2) non-generality of late imprinting, and (3) the very extensive effects of benzpyrene, which in earlier experiments was one of the strongest imprinter at receptorial and behavioral level at any periods of life studied.

Animals↗