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Biomedical subjects

K Németh

Publications and source records attributed to K Németh.

At least 19 recordsLinked to original sources

Anti-inflammatory effect and soft properties of etiprednol dicloacetate (BNP-166), a new, anti-asthmatic steroid.

In vitro and in vivo anti-inflammatory properties and soft characteristics of etiprednol dicloacetate (BNP-166) a new steroid, which has been developed for the treatment of asthma, were investigated in this study. The compound effectively decreased cytokine production in lipopolysaccharide stimulated lymphocytes and attenuated lectin-induced proliferation of blood mononuclear cells in tissue culture. In an animal model of allergen sensitized and challenged Brown Norway rats, using topical treatment, etiprednol dicloacetate substantially attenuated the extent of allergen induced bronchoalveolar fluid eosinophilia. At every examined parameter its pharmacological effects were comparable to those of budesonide. By means of in vitro biological and analytical methods the soft character of BNP-166 was also investigated. The anti-inflammatory effect of etiprednol dicloacetate in vitro was shown to be the function of the quantity of serum components, present in the assay. This loss of activity was most likely the result of the fast metabolism of etiprednol dicloacetate, which in the presence of sera could have been demonstrated by LC/MS/MS. Our data indicate that the significant local effect of the compound will very likely be accompanied with a drastically reduced systemic activity indicating an encouraging selectivity of the pharmacological action of etiprednol dicloacetate.

Adrenal Cortex Hormones↗

fMLP-induced respiratory burst and the intracellular Ca2+ signal are not interrelated in neutrophils.

Reactive oxygen intermediate (ROI) production and the development of the intracellular (IC) Ca2+ ([Ca2+]i) signal by formyl-Met-Leu-Phe (fMLP) stimuli were investigated in neutrophils. When the concentration was varied between 2.3 nM-2.3 microM, ROI production and the [Ca2+]i signal showed different fMLP concentration dependencies. ROI production increased continuously with increasing fMLP concentrations, while the [Ca2+]i signal responses reached a plateau around 230 nM fMLP. Moreover, when a consecutive, 2.3 microM fMLP stimulus was applied 10 min after the first fMLP stimulus, the intensity of the ROI production and that of the [Ca2+]i signal showed a variable dependence on the fMLP concentration of the first stimulus. An initial fMLP dose of 2.3 nM and 23 nM sensitized the cells regarding their ROI production and [Ca2+]i signals. After a first fMLP stimulus of 230 nM, the second stimulus produced an increased [Ca2+]i signal, while no ROI production could be activated. A strong fMLP stimulus of 2.3 microM desensitized the cells regarding both [Ca2+]i signal and ROI production. However, even in these desensitized cells, a high level of ROI production could be evoked by other stimuli like PMA or opsonized zymosan. The differences observed between the fMLP concentration dependence of ROI production and the [Ca2+]i signal strongly suggest that these two phenomena are not interrelated.

Calcium Signaling↗

[Role of the monocye-lymphocye system and of endogenous mediators in the severity of acute pancreatitis and in development of its septic complications].

The activity of monocyte/lymphocyte system and the splanchnic circulation was investigated in acute pancreatitis. The splanchnic blood flow was characterised indirectly by gastric intramucosal pH changes, which strongly correlated with APACHE-II score, and predicted the bad prognosis. The high CD14/HLA-DR and CD14/CD16 coexpression, the low TNF-alpha production proved to be unfavourable prognostic factor in the early phase of the disease. The expression of IL-2, IL-10 and moderately of IL-4 was elevated, but the expression of INF gamma did not show significant alteration. The thrombocyte aggregation decreased in the early phase. There are bad prognostic signs if its level remains constantly low and ATP-release increases. The activity and index of phagocytosis were higher in comparison with controls, but these parameters were not increasable with higher cell concentration. The ROI production increased, and the increase in the fMLP and o'zymosan indicated LDCL seems to be unfavourable prognostic sign, which well correlated with the APACHE-II score.

Acute Disease↗

Effects of saturated and unsaturated fats with vitamin E supplementation on the antioxidant status of broiler chicken tissues.

The influence of fish oil (highly unsaturated) and beef tallow (highly saturated) with vitamin E (100 IU/kg) supplementation on the antioxidant status of broiler chicken cockerels was investigated. Chicks were fed a control diet with no added fat, 40 g/kg each of fish oil and beef tallow diets, respectively, from 11 to 42 days of age. Tocopherol concentration and the rate of lipid peroxidation, thiobarbituric acid reactive substance (TBARS) in liver, fatty acid composition of the liver lipids, blood serum total antioxidant status (TAS), and reduced glutathione (GSH) content were determined. Vitamin E supplementation of the diet increased liver alpha-tocopherol content in chicks regardless of the type of dietary fat. Fish oil diet resulted in higher liver TBARS value while beef tallow diet showed lower values compared to the control diet. Vitamin E supplementation reduced liver TBARS as well as serum GSH, and raised serum TAS for all diets. Serum GSH was the same for vitamin E supplemented diets regardless of the fat supplement. Fish oil diets resulted in a significant increase in hepatic lipid n-3 PUFA content. A significant positive correlation was found between liver TBARS and n-3 PUFA content. No relationships were established, however, between liver TBARS and n-6 PUFA or saturated fatty acids. The results suggest that feeding oils rich in n-3 PUFA increases tissue concentration of these fatty acids, consequently increasing tissue lipid peroxidation and reducing the antioxidative status of broiler chickens. Supplementing high levels of vitamin E with such oils may increase tissue oxidative stability. Serum TAS or GSH may be used as a measure of antioxidative status in chickens.

Animal Feed↗

Peptidyl beta-homo-aspartals (3-amino-4-carboxybutyraldehydes): new specific inhibitors of caspases.

Interleukin-1 beta (IL-1 beta)-converting enzyme (ICE, caspase-1) processes the IL-1 beta precursor to mature inflammatory cytokine IL-1 beta. ICE has been identified as a unique cysteine protease, which cleaves Asp-X bonds, shows resistance to E-64 (an inhibitor of most cysteine proteases) and has a primary structure that is homologous to CED-3, a protein required for apoptosis (programmed cell death) in the nematode Caenorhabditis elegans, and to mammalian cysteine proteases that initiate and execute apoptosis, e.g., apopain/CPP32/caspase-3. The inhibitors of the ICE/CED-3 family or caspases, as they are called recently, may constitute therapeutic agents for amelioration of inflammatory and apoptosis-associated diseases. The most efficient ICE inhibitors are peptide aldehydes and peptidyl chloro or (acyloxy)methanes. A recent study revealed that both D- and L-Asp are accepted by ICE at the P1 of such inhibitors, and the peptidyl (acyloxy)methane analogues having the beta-homo-aspartyl residue [-NH-CH(CH2COOH)-CH2CO-] are inactive. These findings we reexamined in terms of two issues. (a) ICE's resistance to E-64. Since it was thought to be caused by the enzyme's unique substrate specificity, we prepared substrate-based analogues, which were not inhibitory suggesting significant structural difference between the active centers of ICE and papain-like enzymes. (b) Tolerance for D-stereochemistry at the P1 of these inhibitors. In view of the mechanism of cysteine protease inhibition by peptidyl X-methanes, we thought that this phenomenon should be a general characteristic of cysteine proteases and the hAsp-containing analogues should behave as reversible inhibitors. Here, we analyzed the inhibition of ICE and apopain in comparison with that of papain, thrombin, and trypsin by peptide L/D-alpha-aldehydes and their L-beta-homo-aldehyde [-NH-CH(R)-CH2-CHO] analogues. The following results were found. (1) The peptidyl L-beta-homo-aspartals are potent inhibitors for caspases. (2) The L-beta-homo analogues of peptide aldehyde inhibitors designed for other proteases are not inhibitory. (3) Unlike trypsin and thrombin (serine proteases), papain (cysteine protease) shows tolerance for D-stereochemistry at the P1 site of peptide aldehydes in proportion to the lability of the alpha-hydrogen of the P1-D-residue. The complete tolerance of ICE for P1-D-Asp may arise from this residue's high tendency to epimerization. (4) Reaction of cysteine proteases with peptide aldehyde or peptidyl X-methane inhibitors containing P1-D-residues may include alpha-proton abstraction followed by asymmetric induction leading to P1-L-residue-containing products.

Aldehydes↗

Pleiotropic control of glucose and hormone responses by PRL1, a nuclear WD protein, in Arabidopsis.

The prl1 mutation localized by T-DNA tagging on Arabidopsis chromosome 4-44 confers hypersensitivity to glucose and sucrose. The prl1 mutation results in transcriptional derepression of glucose responsive genes defining a novel suppressor function in glucose signaling. The prl1 mutation also augments the sensitivity of plants to growth hormones including cytokinin, ethylene, abscisic acid, and auxin; stimulates the accumulation of sugars and starch in leaves; and inhibits root elongation. PRL1 encodes a regulatory WD protein that interacts with ATHKAP2, an alpha-importin nuclear import receptor, and is imported into the nucleus in Arabidopsis. Potential functional conservation of PRL1 homologs found in other eukaryotes is indicated by nuclear localization of PRL1 in monkey COS-1 cells and selective interaction of PRL1 with a nuclear protein kinase C-betaII isoenzyme involved in human insulin signaling.

Amino Acid Sequence↗

Peptidyl beta-homo-aspartals: specific inhibitors of interleukin-1 beta converting enzyme and its homologues (caspases).

Inhibition of interleukin-1 beta converting enzyme (ICE), apopain, papain, thrombin and trypsin with substrate like peptidyl L- and D-alpha-aldehydes and their L-beta-homo-aldehyde analogues was investigated. The L-beta-homo-aspartals appear to be specific inhibitors for ICE and its homologues; the other enzymes were not inhibited with such L-beta-homo aldehydes. Papain shows tolerance for D-residues at P1 depending on their chiral stability.

Aspartic Acid↗

[Clinical application of analysis of microsatellite markers in the prenatal diagnosis of cystic fibrosis].

Cystic Fibrosis (CF) is an autosomal recessive hereditary disease, caused by the defect of a membrane transport protein. The defect is due to the mutation of the gene coding this protein. To date, these mutations have been analysed by direct mutational analyses in prenatal diagnosis. During gene sequencing, intragenic polymorphic markers (microsatellites) were identified, enabling the indirect analysis of the mutant allele. The markers characterize the given allele, so that the inheritance according to the Mendelian rules could be followed. We introduced a DNA-diagnostic method based on the amplification of three intragenic microsatellites. This new and efficient prenatal diagnostic tool would provide more reliable test results for previously screened CF families, in which direct mutation analysis was not informative.

Cystic Fibrosis↗

Antiapoptotic effect of benzyloxycarbonyl-aspartyl-(beta-tertier-butyl ester)-bromomethylketone (Z-D(OtBu)-Bmk), an intermediate of interleukin-1 beta converting enzyme inhibitors.

The effect of several interleukin-1 beta converting enzyme (ICE) inhibitors on apoptosis was examined. The ICE inhibitors tested were peptide aldehydes such as ethyloxycarbonyl-Ala-Tyr-Val-Ala-Asp-aldehyde (Etoco-AYVAD-CHO), acetyl-Tyr-Val-Ala-Asp-aldehyde (Ac-YVAD-CHO), benzyloxycarbonyl-Val-His-Asp-aldehyde (Z-VHD-CHO), a tetrapeptide chloromethylketone, acetyl-Tyr-Val-Ala-Asp-chloromethylketone (Ac-YVAD-Cmk) and their common intermediate benzyloxycarbonyl-Asp-(beta-tertier-butyl ester)-bromomethylketone (Z-D(OtBu)-Bmk). Apoptosis was induced with several chemical agents conventionally used for this purpose in THP-1, L929, NB-41A3 cell lines and mouse thymocytes. DNA fragmentation during apoptosis was measured by conventional gel electrophoresis and ELISA. The cell morphology was examined by hematoxylin/eosin staining method. Cell viability was also monitored by MTT assay. Contrary to expectations, the peptide aldehydes listed above and Ac-YVAD-Cmk, known as highly specific ICE inhibitors, did not inhibit the apoptosis of these cell types. However, Z-D(OtBu)-Bmk, which had no relevant inhibitory activity on ICE, potently blocked the DNA fragmentation in THP-1 cells and thymocytes whichever of the inducing agents was used. In the other two cell lines Z-D(OtBu)-Bmk was inactive. The apoptotic cell morphology was also inhibited by Z-D(OtBu)-Bmk. Nevertheless, Z-D(OtBu)-Bmk failed to prevent the loss of mitochondrial activity and the cell destruction in the late phase of apoptosis. These data suggest that ICE is not involved in the apoptotic cell death induced by chemical agents. Thus, Z-D(OtBu)-Bmk, a common intermediate of some ICE inhibitors, may be a useful antiapoptotic agent for studying the early events of apoptosis in some cell types.

Aldehydes↗

Expression of a novel-type small proline-rich protein gene of alfalfa is induced by 2,4-dichlorophenoxiacetic acid in dedifferentiated callus cells.

Differential screening of a cDNA library of 2,4-dichlorophenoxiacetic acid (2,4-D)-treated alfalfa (Medicago sativa) callus tissues resulted in the isolation of a 571 bp cDNA clone (MsPRP5) encoding for a proline-rich protein (84 amino acids) with a specific repeat unit of TPVLPPRK/RGRPPPVPP. In addition, a characteristic amino acid block (PPVYK) previously found in other proline-rich proteins also occurs in the C-terminal region of MsPRP5. At the N-terminal, a signal peptide similar to leader sequences of extracellular proteins can be predicted. According to the northern analysis, the corresponding gene is not expressed or is weakly expressed in differentiated vegetative organs and somatic embryos. However the accumulation of MsPRP5 mRNA is auxin concentration-dependent in dedifferentiated callus tissue. An increase in the amount of steady-state mRNA was detected already 20 min after auxin shock (100 microM 2,4-D). Maximum expression was observed at 24-48 h in the presence of 2,4-D. Elevated expression was also found in cells recovering after heat shock and wounding stress. In synchronized alfalfa cells, the transcript level of MsPRP5 gene fluctuated during cell cycle progression with peaks in G1/S phase cells. Considering the structural features and expression properties of MsPRP5, this clone may represents a new type of proline-rich protein gene which responds to hormonal shock and some other stresses as well.

2,4-Dichlorophenoxyacetic Acid↗

[Analysis of five mutations of cystic fibrosis occurring in the Hungarian population].

The authors screened 374 patients clinically diagnosed be affected by cystic fibrosis. Mutations delta F508, G542X, G551D, R553X, N1303K were analysed to obtain genetic diagnosis. The large number of patients involved in this study allowed for authors to present precise data of the frequencies of these mutations in Hungary. The frequency of mutation delta F508 is found to be significantly less then the numbers reported in other studies. This is due to sampling bias occurring at little sample sizes. Mutational analysis has been used as a tool of prenatal diagnosis.

Adult↗

Brassinosteroids rescue the deficiency of CYP90, a cytochrome P450, controlling cell elongation and de-etiolation in Arabidopsis.

The cpd mutation localized by T-DNA tagging on Arabidopsis chromosome 5-14.3 inhibits cell elongation controlled by the ecdysone-like brassinosteroid hormone brassinolide. The cpd mutant displays de-etiolation and derepression of light-induced genes in the dark, as well as dwarfism, male sterility, and activation of stress-regulated genes in the light. The CPD gene encodes a cytochrome P450 (CYP90) sharing homologous domains with steroid hydroxylases. The phenotype of the cpd mutant is restored to wild type both by feeding with C23-hydroxylated brassinolide precursors and by ectopic overexpression of the CPD cDNA. Brassinosteroids also compensate for different cell elongation defects of Arabidopsis det, cop, fus, and axr2 mutants, indicating that these steroids play an essential role in the regulation of plant development.

Arabidopsis↗

Measurement and drug induced modulation of interleukin-1 level during zymosan peritonitis in mice.

The time-course and pharmacological modulation of interleukin-1 (IL-1) production were investigated during zymosan induced peritonitis in mice. IL-1 alpha liberation was assessed by specific immunoassay (ELISA) and the IL-1 like bioactivity (sensitive to both alpha- and beta-forms of IL-1) was measured by a sensitive bioassay (D10G4.1 costimulation). I.p. injection of zymosan induced significant IL-1 release into the peritoneal exudate. The level peaked at 4 h and by 24 h dropped below the detection limit in both assays. The effects of the prototypical antiinflammatory drugs indomethacin (IND) and dexamethasone (DEX) and that of IX 207-887, a compound which has been reported to interfere primarily with IL-1 production, were also tested. DEX and IX 207-887 dose-dependently decreased the immunoassayable IL-1 alpha level and the IL-1 like bioactivity as well. However, IND had no suppressant effect. Thus, the data obtained by immunoassay and bioassay correlated well proving the suitability of zymosan peritonitis model for the examination of IL-1 production in experimental inflammation.

Analysis of Variance↗

Effect of peptide aldehydes with IL-1 beta converting enzyme inhibitory properties on IL-1 alpha and IL-1 beta production in vitro.

Tripeptide and pentapeptide aldehydes as substrate-base inhibitors of cysteine proteases were designed in our laboratory for the inhibition of interleukin-1 beta converting enzyme (ICE), a recently described cysteine protease responsible for the processing of IL-1 beta. The biological effectivity of the peptide aldehydes was studied in THP-1 cells and human whole blood. The released and cell-associated IL-1 alpha and IL-1 beta levels were determined by ELISA from the supernatants and cell lysates, respectively. The total IL-1 like bioactivity was assayed by the D10 G4.1 cell proliferation method. The tripeptide aldehyde (Z-Val-His-Asp-H) and pentapeptide aldehyde (Eoc-Ala-Tyr-Val-Ala-Asp-H) significantly reduced IL-1 beta levels in the supernatants in relatively high concentrations (10-100 microM), but the IL-1 alpha release was unaffected by these peptides. However, a considerable decrease in the cell-associated IL-1 beta and IL-1 alpha levels was observed. N-terminal extension of the tripeptide aldehyde yielded even more potent inhibitors. Amino acid substitution at the P2 position did not cause considerable changes in the inhibitory activity. The peptide aldehydes suppressed the IL-1 beta production in a reversible manner, whereas dexamethasone, a glucocorticoid, had a prolonged inhibitory effect. The inhibitory effect of these peptides and that of dexamethasone appeared to be additive. These findings indicate that these peptide aldehydes might be used as IL-beta inhibitory agents in experimental models in which IL-1 beta is a key mediator or ICE is implicated.

Aldehydes↗

[Leukocyte adhesion defect--a rare form of congenital immune deficiency].

Leukocyte adhesion defect (LAD) is an inherited defect of phagocytic function. This disorder is characterised by delayed separation of the umbilical cord, severe recurrent bacterial infections, impaired formation of pus, and high leukocyte counts. The granulocytes have severe defect in their chemotactic mobility and endocytosis. The disease is attributed to the absence of the leukocyte adhesion molecules. (CD11/CD18), which can be verified with monoclonal antibodies. The authors describe the disease-process of the first patient diagnosed in Hungary. Perinatally the omphalitis, periumbilical abscess and periproctal abscess leading to rectovaginal fistula, in the first months the otitis, mastoiditis, and expressed leukocytosis referred to the impaired function of phagocytic cells, which was verified by laboratory tests as well. The decreased inflammation and cicatrization were also striking. This severe form of LAD can be cured only by bone marrow transplantation with preliminary sanitation of the foci of infection. It took about six months. Unfortunately, the patient died of sepsis immediately before transplantation.

Antibodies, Monoclonal↗