Katalin Böddi - Academia.edu (original) (raw)

Papers by Katalin Böddi

Research paper thumbnail of The effect of high-irradiance rapid polymerization on degree of conversion, monomer elution, polymerization shrinkage and porosity of bulk-fill resin composites

Research paper thumbnail of Effect of Pre-Heating on the Monomer Elution and Porosity of Conventional and Bulk-Fill Resin-Based Dental Composites

International Journal of Molecular Sciences

The pre-heating of dental resin-based composites (RBCs) improves adaptability to cavity walls, re... more The pre-heating of dental resin-based composites (RBCs) improves adaptability to cavity walls, reducing microleakages. However, the rapid cooling of the pre-heated RBC may change the polymerization kinetics, and thus the final network configuration of the RBC. It is well known that unreacted monomers remaining in the set RBC can leach into the oral cavity. However, it is still not clear how the pre-heating and cooling of RBCs alter monomer elution (ME). Thus, the purpose was to determine the ME from room-temperature and pre-heated RBCs, in addition to determining the closed porosity (CP) volume. Bulk-filled RBCs and layered conventional RBC samples were prepared. The pre-polymerization temperature was set at 24 °C and 55/65 °C. The ME from RBC samples was assessed with high-performance liquid chromatography using standard monomers. CP was measured with micro-computed tomography. ME decreased significantly from bulk fills and increased from layered samples as a result of pre-heating....

Research paper thumbnail of Pre-Heating Effect on Monomer Elution and Degree of Conversion of Contemporary and Thermoviscous Bulk-Fill Resin-Based Dental Composites

Polymers, 2021

Detection of unreacted monomers from pre-heated resin-based dental composites (RBC) is not a well... more Detection of unreacted monomers from pre-heated resin-based dental composites (RBC) is not a well-investigated topic so far. The objectives were to determine the temperature changes during the application and polymerization, the degree of conversion (DC) and unreacted monomer elution of room temperature (RT), and pre-heated thermoviscous [VisCalor Bulk(VCB)] and high-viscosity full-body contemporary [Filtek One Bulk(FOB)] bulk-fill RBCs. The RBCs’ temperatures during the sample preparation were recorded with a K-type thermocouple. The DC at the top and bottom was measured with micro-Raman spectroscopy and the amounts of eluted BisGMA, UDMA, DDMA, and TEGDMA were assessed with High-Performance Liquid Chromatography. The temperatures of the pre-heated RBCs decreased rapidly during the manipulation phase. The temperature rise during photopolymerization reflects the bottom DCs. The differences in DC% between the top and the bottom were significant. RT VCB had a lower DC% compared to FOB...

Research paper thumbnail of Colistin resistance associated with outer membrane protein change in Klebsiella pneumoniae and Enterobacter asburiae

Acta Microbiologica et Immunologica Hungarica, 2017

In this study, outer membrane proteins (OMPs) of colistin-resistant Klebsiella pneumoniae and Ent... more In this study, outer membrane proteins (OMPs) of colistin-resistant Klebsiella pneumoniae and Enterobacter asburiae were analyzed. One colistin-susceptible and three colistin-resistant K. pneumoniae sequence type 258 strains as well as one colistin-susceptible E. asburiae and its colistin-heteroresistant counterpart strain were involved in the study. OMP analysis of each strain was performed by microchip method. Matrix-assisted laser desorption ionization time of flight/mass spectrometry (MALDI-TOF/MS) investigation was carried out after separation of OMPs by two-dimensional gel electrophoresis and in-gel digestion. The MALDI-TOF/MS analysis of OMPs in the colistin-susceptible K. pneumoniae found 16 kDa proteins belonging to the LysM domain/BON superfamily, as well as DNA starvation proteins, whereas OmpX and OmpW were detected in the colistin-resistant counterpart strains. OmpC and OmpW were detected in the colistin-susceptible E. asburiae, whereas OmpA and OmpX were identified in ...

Research paper thumbnail of Degree of Conversion and BisGMA, TEGDMA, UDMA Elution from Flowable Bulk Fill Composites

International journal of molecular sciences, Jan 20, 2016

The degree of conversion (DC) and the released bisphenol A diglycidyl ether dimethacrylate (BisGM... more The degree of conversion (DC) and the released bisphenol A diglycidyl ether dimethacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA) monomers of bulk-fill composites compared to that of conventional flowable ones were assessed using micro-Raman spectroscopy and high performance liquid chromatography (HPLC). Four millimeter-thick samples were prepared from SureFil SDR Flow (SDR), X-tra Base (XB), Filtek Bulk Fill (FBF) and two and four millimeter samples from Filtek Ultimate Flow (FUF). They were measured with micro-Raman spectroscopy to determine the DC% of the top and the bottom surfaces. The amount of released monomers in 75% ethanol extraction media was measured with HPLC. The differences between the top and bottom DC% were significant for each material. The mean DC values were in the following order for the bottom surfaces: SDR_4mm_20s > FUF_2mm_20s > XB_4mm_20s > FBF_4mm_20s > XB_4mm_10s > FBF_4mm_10s > FUF_4mm_20s...

Research paper thumbnail of Role of Tyrosine Isomers in Acute and Chronic Diseases Leading to Oxidative Stress - A Review

Current Medicinal Chemistry, 2016

Oxidative stress plays a major role in the pathogenesis of a variety of acute and chronic disease... more Oxidative stress plays a major role in the pathogenesis of a variety of acute and chronic diseases. Measurement of the oxidative stress-related end products may be performed, e.g. that of structural isomers of the physiological para-tyrosine, namely meta-and ortho-tyrosine, that are oxidized derivatives of phenylalanine. Recent data suggest that in sepsis, serum level of meta-tyrosine increases, which peaks on the 2 nd and 3 rd days (p<0.05 vs. controls), and the kinetics follows the intensity of the systemic inflammation correlating with serum procalcitonin levels. In a similar study subset, urinary meta-tyrosine excretion correlated with both need of daily insulin dose and the insulin-glucose product in non-diabetic septic cases (p<0.01 for both). Using linear regression model, meta-tyrosine excretion, urinary meta-tyrosine/para-tyrosine, urinary ortho-tyrosine/para-tyrosine and urinary (meta-+ orthotyrosine)/para-tyrosine proved to be markers of carbohydrate homeostasis. In a chronic rodent model, we tried to compensate the abnormal tyrosine isomers using para-tyrosine, the physiological amino acid. Rats were fed a standard high cholesterol-diet, and were given para-tyrosine or vehicle orally. High-cholesterol feeding lead to a significant increase in aortic wall meta-tyrosine content and a decreased vasorelaxation of the aorta to insulin and the glucagon-like peptide-1 analogue, liraglutide, that both could be prevented by administration of para-tyrosine. Concluding, these data suggest that meta-and ortho-tyrosine are potential markers of oxidative stress in acute diseases related to oxidative stress, and may also interfere with insulin action in septic humans. Competition of meta-and ortho-tyrosine by supplementation of para-tyrosine may exert a protective role in oxidative stress-related diseases.

Research paper thumbnail of Elevated Vascular Level of ortho-Tyrosine Contributes to the Impairment of Insulin-Induced Arterial Relaxation

Hormone and Metabolic Research, 2014

Elevated Vascular Level of ortho-Tyrosine Contributes to the Impairment of Insulin-Induced Arteri... more Elevated Vascular Level of ortho-Tyrosine Contributes to the Impairment of Insulin-Induced Arterial Relaxation others-can modify phenylalanine residues to form para-, meta-and ortho-tyrosines (p-, m-and o-Tyr) [ 11-14 ]. Modifi ed amino acids could originate from protein-bound amino acids [ 11 ] or may be incorporated into proteins during their synthesis resulting in a polypeptide without direct oxidative damage of the protein itself [ 15-17 ]. In line with these fi ndings, free m-Tyr was shown to be incorporated into cellular proteins, possibly via protein synthesis, which then can exert cytotoxic actions [ 17 ]. Furthermore, o-Tyr and m-Tyr levels were found to be signifi cantly higher in the aortic tissue of hyperglycemic cynomolgus monkeys and that of rats with aortic banding-induced hypertension [ 11 , 18 ]. Misincorporation of o-Tyr and m-Tyr into structural or catalytic proteins could also contribute to impaired cellular function, such as erythropoietin-hyporesponsiveness in erythroblasts and inhibition of tumor growth in vivo, possibly by interfering with MAP/ERK signaling [ 19 , 20 ]. Of note, cytotoxicity of m-Tyr can be blocked in vitro with phenylalanine [ 15 ] , suggesting that L-phenylalanine tRNA synthase recognizes m-Tyr to aff ect incorporation of ROS-damaged amino acids into cellular proteins [ 15 ]. However, Affi liations Affi liation addresses are listed at the end of the article THIEME License terms

Research paper thumbnail of Peptidomic/Proteomic Profiling of Human Embryo Sectretome

Research paper thumbnail of Palladium-catalyzed diaminocarbonylation: synthesis of androstene dimers containing 3,3′- or 17,17′-dicarboxamide spacers

Monatshefte für Chemie - Chemical Monthly, 2014

Novel androstene-based dimers linked through A-and D-ring with 3,3 0-and 17,17 0-dicarboxamide sp... more Novel androstene-based dimers linked through A-and D-ring with 3,3 0-and 17,17 0-dicarboxamide spacers, were synthesized via palladium-catalyzed aminocarbonylation. Androstane derivatives possessing either 3-iodo-3,5diene or 17-iodo-16-ene functionality were used as substrates in the presence of palladium-phosphine in situ catalysts and aliphatic and aromatic diamines as N-nucleophiles. Since androst-4-ene-3,17-dione was used as starting material, a multistep synthesis including protection/deprotection of one of the keto functionalities (3-one or 17-one) as ethylene ketals, transformation of the other keto group to iodoalkene functionality via its hydrazone, and palladium-catalyzed aminocarbonylation of the iodoalkene functionality was used. In this way, new dimeric compounds possessing a keto functionality were obtained in moderate-to-good isolated yields, via highly chemoselective reactions, under relatively mild conditions.

Research paper thumbnail of Investigations of non-enzymatic glycation with new bioanalytical methods

Research paper thumbnail of Measurement of the modification and interference rate of urinary albumin detected by size-exclusion HPLC

Physiological Measurement, 2009

The measurement of the excretion of urinary albumin (albuminuria) is an important and well-establ... more The measurement of the excretion of urinary albumin (albuminuria) is an important and well-established method to assess clinical outcomes. A highperformance liquid chromatography (HPLC) method has been introduced to measure albuminuria. Using this method, it was found that commonly used immunological methods do not measure a fraction of urinary albumin. Some authors presumed that the reason of immuno-unreactivity is the modification of urinary albumin; some others presumed that the difference is merely because of interference. In order to decide this question, we established an HPLC method equipped with tandem UV and fluorescent detection to assess the changes in the detectability of albumin with the rate of modification. For this measurement, differently modified forms of albumin were used. Urine samples of diabetic patients were also measured to find a potential connection between the modification rate and clinical parameters. Secondly, we have established a reversed phase HPLC method to assess the interference rate. We conclude that albumin modification does not affect immunoreactivity. The modification rate of urinary albumin in diabetic patients showed a correlation with renal function. The interference rate of the albumin peak was found to be 12.7% on average, which does not explain the difference between the two methods.

Research paper thumbnail of Detection of the antibacterial effect of essential oils on outer membrane proteins of Pseudomonas aeruginosa by lab-on-a-chip and MALDI-TOF/MS

Flavour and Fragrance Journal, 2013

In bacteria, structural changes of outer membrane protein (OMP) composition may have an effect on... more In bacteria, structural changes of outer membrane protein (OMP) composition may have an effect on the adhesive ability and pathogenic properties of the organisms. Pseudomonas aeruginosa can develop an intrinsic resistance to a wide range of biocides, which is associated with the nature of its outer membrane. The aim of our study was to examine how the essential oils of cinnamon bark and clove modify the OMP composition of the human pathogen P. aeruginosa strains and to identify the structure of proteins that are considerably changed after incubation with essential oils. Chemical composition of the oils was analysed by using gas chromatography and gas chromatography-mass spectrometry. Eugenol (83.7%) was the main component of the clove oil, while trans-cinnamic aldehyde (73.2%) was the main constituent in cinnamon bark oil. Values for the minimum inhibitory concentration (MIC) of the oils were determined by a modified tube dilution method. The oils were administered to the culture at concentrations of 0.5 Â MIC and 2 Â MIC and incubated for 60 min. After OMP preparation, the structure of proteins was analysed by MALDI-TOF/MS. Cinnamon and clove oil could influence the OMP composition of Pseudomonas strains. Proteins with molecular weights of 42.7 kDa and 79.4 kDa disappeared after treatment with cinnamon and clove oil, respectively. Quantitative changes in the protein profile may contribute to the explanation of the antibacterial effect of cinnamon bark and clove essential oils on pathogenic Pseudomonas strains.

Research paper thumbnail of Quantification of Conversion Degree and Monomer Elution from Dental Composite Using HPLC and Micro-Raman Spectroscopy

Chromatographia, 2014

layer increment up to 3 mm from the top led to 10 % decrease in DC and 30-35 % increase in monome... more layer increment up to 3 mm from the top led to 10 % decrease in DC and 30-35 % increase in monomer elution. Further increase in depth from 3 to 4 mm caused 30 % drop in DC and 55 % increase in the amount of leached monomers. The overall result of the findings indicates that direct correlation exists between DC of composite and the elution of unreacted monomers.

Research paper thumbnail of Enrichment of Amadori products derived from the nonenzymatic glycation of proteins using microscale boronate affinity chromatography

Analytical Biochemistry, 2009

Scheme 1. Mechanism of binding and elution processes between cis-diol-containing Amadori peptides... more Scheme 1. Mechanism of binding and elution processes between cis-diol-containing Amadori peptides and boronic acid.

Research paper thumbnail of Synthesis, Pharmacokinetic Characterization and Antioxidant Capacity of Carotenoid Succinates and Their Melatonin Conjugates

Molecules

Carotenoid succinates were synthesized from hydroxy carotenoids and were coupled to a commerciall... more Carotenoid succinates were synthesized from hydroxy carotenoids and were coupled to a commercially available derivative of melatonin via amide bond for producing more powerful anti-oxidants and yet new hybrid lipophilic bifunctional molecules with additional therapeutic effects. The coupling reactions produced conjugates in acceptable to good yields. Succinylation increased the water solubility of the carotenoids, while the conjugation with melatonin resulted in more lipophilic derivatives. The conjugates showed self-assembly in aqueous medium and yielded relatively stable colloidal solutions in phosphate-buffered saline. Antioxidant behavior was measured with ABTS and the FRAP methods for the carotenoids, the carotenoid succinates, and the conjugates with melatonin. A strong dependence on the quality of the solvent was observed. TEAC values of the new derivatives in phosphate-buffered saline were found to be comparable to or higher than those of parent carotenoids, however, synergi...

Research paper thumbnail of Study on the Synthesis, Antioxidant Properties, and Self-Assembly of Carotenoid–Flavonoid Conjugates

Molecules, Feb 1, 2020

Flavonoids and carotenoids possess beneficial physiological effects, such as high antioxidant cap... more Flavonoids and carotenoids possess beneficial physiological effects, such as high antioxidant capacity, anticarcinogenic, immunomodulatory, and anti-inflammatory properties, as well as protective effects against UV light. The covalent coupling of hydrophobic carotenoids with hydrophilic flavonoids, such as daidzein and chrysin, was achieved, resulting in new amphipathic structures. 7-Azidohexyl ethers of daidzein and chrysin were prepared in five steps, and their azide-alkyne [4 + 2] cycloaddition with pentynoates of 8′-apo-β-carotenol, zeaxanthin, and capsanthin afforded carotenoid–flavonoid conjugates. The trolox-equivalent antioxidant capacity against ABTS•+ radical cation and self-assembly of the final products were examined. The 1:1 flavonoid–carotenoid hybrids generally showed higher antioxidant activity than their parent flavonoids but lower than that of the corresponding carotenoids. The diflavonoid hybrids of zeaxanthin and capsanthin, however, were found to exhibit a synergistic enhancement in antioxidant capacities. ECD (electronic circular dichroism) and UV-vis analysis of zeaxanthin–flavonoid conjugates revealed that they form different optically active J-aggregates in acetone/water and tetrahydrofuran/water mixtures depending on the solvent ratio and type of the applied aprotic polar solvent, while the capsanthin derivatives showed no self-assembly. The zeaxanthin bis-triazole conjugates with daidzein and with chrysin, differing only in the position of a phenolic hydroxyl group, showed significantly different aggregation profile upon the addition of water.

Research paper thumbnail of PEPTIDOMIC/PROTEOMIC PROFILING OF HUMAN EMBRYO SECTRETOME

Research paper thumbnail of Potential urinary biomarkers of disease activity in Crohn's disease

Scandinavian Journal of Gastroenterology, 2010

Measurement of the immunoreactive urinary albumin (ir-uAlb) concentration by immunological method... more Measurement of the immunoreactive urinary albumin (ir-uAlb) concentration by immunological methods was found to be an effective method to identify disease activity in Crohn&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease (CD). Recently a size-exclusion (SE) high performance liquid chromatography (HPLC) method was developed to measure both ir-uAlb and non-immunoreactive urinary albumin (total, t-uAlb). We aimed to follow-up one of our CD patients with frequent remissions and exacerbation phases comparing the changes of disease activity parameters and the concentration of ir-uAlb and t-uAlb. The surprising results led us to perform measurements in greater depth. Concentration of ir-uAlb was measured by immunoturbidimetry (IT) and t-uAlb by SE-HPLC. Albumin peak of SE-HPLC was collected and applied to a reversed-phase (RP) HPLC and to gel-electrophoresis. Eluted peaks of RP-HPLC and identified bands of gel-electrophoresis were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). The concentration of t-uAlb was 15 times higher than that of the ir-uAlb during active state. The RP-HPLC and the gel-electrophoresis separation proved that albumin peak by size-exclusion consists of three different peaks. MALDI-TOF/MS measurements identified α1-acid-glycoprotein and Zn-α2-glycoprotein as major, and albumin as minor protein. Peak of albumin of SE-HPLC contains a significant amount of glycoprotein during the active phase of CD, which could not be detected in remission. Urinary α1-acid-glycoprotein and/or Zn-α2-glycoprotein could be an ideal disease activity biomarker of CD.

Research paper thumbnail of Quantification of Conversion Degree and Monomer Elution from Dental Composite Using HPLC and Micro-Raman Spectroscopy

Chromatographia, 2014

layer increment up to 3 mm from the top led to 10 % decrease in DC and 30-35 % increase in monome... more layer increment up to 3 mm from the top led to 10 % decrease in DC and 30-35 % increase in monomer elution. Further increase in depth from 3 to 4 mm caused 30 % drop in DC and 55 % increase in the amount of leached monomers. The overall result of the findings indicates that direct correlation exists between DC of composite and the elution of unreacted monomers.

Research paper thumbnail of Investigation of Phenolic Components of Hungarian Wines

International Journal of Molecular Sciences, 2007

Ninety-two wines from the southernmost wine-producing region in Hungary (Villány) were analyzed f... more Ninety-two wines from the southernmost wine-producing region in Hungary (Villány) were analyzed for their polyphenolic content by high performance liquid chromatography (HPLC). Our results show that wine variety or vintage year could not be distinguished based on polyphenol content, but winery origin could be. Resveratrol concentration is mainly dependent on variety and vintage year. The "human factor" (i.e., winemaking style and technology) seems to be more decisive for the polyphenolic composition of red wines than other factors, such as variety and vintage year.

Research paper thumbnail of The effect of high-irradiance rapid polymerization on degree of conversion, monomer elution, polymerization shrinkage and porosity of bulk-fill resin composites

Research paper thumbnail of Effect of Pre-Heating on the Monomer Elution and Porosity of Conventional and Bulk-Fill Resin-Based Dental Composites

International Journal of Molecular Sciences

The pre-heating of dental resin-based composites (RBCs) improves adaptability to cavity walls, re... more The pre-heating of dental resin-based composites (RBCs) improves adaptability to cavity walls, reducing microleakages. However, the rapid cooling of the pre-heated RBC may change the polymerization kinetics, and thus the final network configuration of the RBC. It is well known that unreacted monomers remaining in the set RBC can leach into the oral cavity. However, it is still not clear how the pre-heating and cooling of RBCs alter monomer elution (ME). Thus, the purpose was to determine the ME from room-temperature and pre-heated RBCs, in addition to determining the closed porosity (CP) volume. Bulk-filled RBCs and layered conventional RBC samples were prepared. The pre-polymerization temperature was set at 24 °C and 55/65 °C. The ME from RBC samples was assessed with high-performance liquid chromatography using standard monomers. CP was measured with micro-computed tomography. ME decreased significantly from bulk fills and increased from layered samples as a result of pre-heating....

Research paper thumbnail of Pre-Heating Effect on Monomer Elution and Degree of Conversion of Contemporary and Thermoviscous Bulk-Fill Resin-Based Dental Composites

Polymers, 2021

Detection of unreacted monomers from pre-heated resin-based dental composites (RBC) is not a well... more Detection of unreacted monomers from pre-heated resin-based dental composites (RBC) is not a well-investigated topic so far. The objectives were to determine the temperature changes during the application and polymerization, the degree of conversion (DC) and unreacted monomer elution of room temperature (RT), and pre-heated thermoviscous [VisCalor Bulk(VCB)] and high-viscosity full-body contemporary [Filtek One Bulk(FOB)] bulk-fill RBCs. The RBCs’ temperatures during the sample preparation were recorded with a K-type thermocouple. The DC at the top and bottom was measured with micro-Raman spectroscopy and the amounts of eluted BisGMA, UDMA, DDMA, and TEGDMA were assessed with High-Performance Liquid Chromatography. The temperatures of the pre-heated RBCs decreased rapidly during the manipulation phase. The temperature rise during photopolymerization reflects the bottom DCs. The differences in DC% between the top and the bottom were significant. RT VCB had a lower DC% compared to FOB...

Research paper thumbnail of Colistin resistance associated with outer membrane protein change in Klebsiella pneumoniae and Enterobacter asburiae

Acta Microbiologica et Immunologica Hungarica, 2017

In this study, outer membrane proteins (OMPs) of colistin-resistant Klebsiella pneumoniae and Ent... more In this study, outer membrane proteins (OMPs) of colistin-resistant Klebsiella pneumoniae and Enterobacter asburiae were analyzed. One colistin-susceptible and three colistin-resistant K. pneumoniae sequence type 258 strains as well as one colistin-susceptible E. asburiae and its colistin-heteroresistant counterpart strain were involved in the study. OMP analysis of each strain was performed by microchip method. Matrix-assisted laser desorption ionization time of flight/mass spectrometry (MALDI-TOF/MS) investigation was carried out after separation of OMPs by two-dimensional gel electrophoresis and in-gel digestion. The MALDI-TOF/MS analysis of OMPs in the colistin-susceptible K. pneumoniae found 16 kDa proteins belonging to the LysM domain/BON superfamily, as well as DNA starvation proteins, whereas OmpX and OmpW were detected in the colistin-resistant counterpart strains. OmpC and OmpW were detected in the colistin-susceptible E. asburiae, whereas OmpA and OmpX were identified in ...

Research paper thumbnail of Degree of Conversion and BisGMA, TEGDMA, UDMA Elution from Flowable Bulk Fill Composites

International journal of molecular sciences, Jan 20, 2016

The degree of conversion (DC) and the released bisphenol A diglycidyl ether dimethacrylate (BisGM... more The degree of conversion (DC) and the released bisphenol A diglycidyl ether dimethacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA) monomers of bulk-fill composites compared to that of conventional flowable ones were assessed using micro-Raman spectroscopy and high performance liquid chromatography (HPLC). Four millimeter-thick samples were prepared from SureFil SDR Flow (SDR), X-tra Base (XB), Filtek Bulk Fill (FBF) and two and four millimeter samples from Filtek Ultimate Flow (FUF). They were measured with micro-Raman spectroscopy to determine the DC% of the top and the bottom surfaces. The amount of released monomers in 75% ethanol extraction media was measured with HPLC. The differences between the top and bottom DC% were significant for each material. The mean DC values were in the following order for the bottom surfaces: SDR_4mm_20s > FUF_2mm_20s > XB_4mm_20s > FBF_4mm_20s > XB_4mm_10s > FBF_4mm_10s > FUF_4mm_20s...

Research paper thumbnail of Role of Tyrosine Isomers in Acute and Chronic Diseases Leading to Oxidative Stress - A Review

Current Medicinal Chemistry, 2016

Oxidative stress plays a major role in the pathogenesis of a variety of acute and chronic disease... more Oxidative stress plays a major role in the pathogenesis of a variety of acute and chronic diseases. Measurement of the oxidative stress-related end products may be performed, e.g. that of structural isomers of the physiological para-tyrosine, namely meta-and ortho-tyrosine, that are oxidized derivatives of phenylalanine. Recent data suggest that in sepsis, serum level of meta-tyrosine increases, which peaks on the 2 nd and 3 rd days (p<0.05 vs. controls), and the kinetics follows the intensity of the systemic inflammation correlating with serum procalcitonin levels. In a similar study subset, urinary meta-tyrosine excretion correlated with both need of daily insulin dose and the insulin-glucose product in non-diabetic septic cases (p<0.01 for both). Using linear regression model, meta-tyrosine excretion, urinary meta-tyrosine/para-tyrosine, urinary ortho-tyrosine/para-tyrosine and urinary (meta-+ orthotyrosine)/para-tyrosine proved to be markers of carbohydrate homeostasis. In a chronic rodent model, we tried to compensate the abnormal tyrosine isomers using para-tyrosine, the physiological amino acid. Rats were fed a standard high cholesterol-diet, and were given para-tyrosine or vehicle orally. High-cholesterol feeding lead to a significant increase in aortic wall meta-tyrosine content and a decreased vasorelaxation of the aorta to insulin and the glucagon-like peptide-1 analogue, liraglutide, that both could be prevented by administration of para-tyrosine. Concluding, these data suggest that meta-and ortho-tyrosine are potential markers of oxidative stress in acute diseases related to oxidative stress, and may also interfere with insulin action in septic humans. Competition of meta-and ortho-tyrosine by supplementation of para-tyrosine may exert a protective role in oxidative stress-related diseases.

Research paper thumbnail of Elevated Vascular Level of ortho-Tyrosine Contributes to the Impairment of Insulin-Induced Arterial Relaxation

Hormone and Metabolic Research, 2014

Elevated Vascular Level of ortho-Tyrosine Contributes to the Impairment of Insulin-Induced Arteri... more Elevated Vascular Level of ortho-Tyrosine Contributes to the Impairment of Insulin-Induced Arterial Relaxation others-can modify phenylalanine residues to form para-, meta-and ortho-tyrosines (p-, m-and o-Tyr) [ 11-14 ]. Modifi ed amino acids could originate from protein-bound amino acids [ 11 ] or may be incorporated into proteins during their synthesis resulting in a polypeptide without direct oxidative damage of the protein itself [ 15-17 ]. In line with these fi ndings, free m-Tyr was shown to be incorporated into cellular proteins, possibly via protein synthesis, which then can exert cytotoxic actions [ 17 ]. Furthermore, o-Tyr and m-Tyr levels were found to be signifi cantly higher in the aortic tissue of hyperglycemic cynomolgus monkeys and that of rats with aortic banding-induced hypertension [ 11 , 18 ]. Misincorporation of o-Tyr and m-Tyr into structural or catalytic proteins could also contribute to impaired cellular function, such as erythropoietin-hyporesponsiveness in erythroblasts and inhibition of tumor growth in vivo, possibly by interfering with MAP/ERK signaling [ 19 , 20 ]. Of note, cytotoxicity of m-Tyr can be blocked in vitro with phenylalanine [ 15 ] , suggesting that L-phenylalanine tRNA synthase recognizes m-Tyr to aff ect incorporation of ROS-damaged amino acids into cellular proteins [ 15 ]. However, Affi liations Affi liation addresses are listed at the end of the article THIEME License terms

Research paper thumbnail of Peptidomic/Proteomic Profiling of Human Embryo Sectretome

Research paper thumbnail of Palladium-catalyzed diaminocarbonylation: synthesis of androstene dimers containing 3,3′- or 17,17′-dicarboxamide spacers

Monatshefte für Chemie - Chemical Monthly, 2014

Novel androstene-based dimers linked through A-and D-ring with 3,3 0-and 17,17 0-dicarboxamide sp... more Novel androstene-based dimers linked through A-and D-ring with 3,3 0-and 17,17 0-dicarboxamide spacers, were synthesized via palladium-catalyzed aminocarbonylation. Androstane derivatives possessing either 3-iodo-3,5diene or 17-iodo-16-ene functionality were used as substrates in the presence of palladium-phosphine in situ catalysts and aliphatic and aromatic diamines as N-nucleophiles. Since androst-4-ene-3,17-dione was used as starting material, a multistep synthesis including protection/deprotection of one of the keto functionalities (3-one or 17-one) as ethylene ketals, transformation of the other keto group to iodoalkene functionality via its hydrazone, and palladium-catalyzed aminocarbonylation of the iodoalkene functionality was used. In this way, new dimeric compounds possessing a keto functionality were obtained in moderate-to-good isolated yields, via highly chemoselective reactions, under relatively mild conditions.

Research paper thumbnail of Investigations of non-enzymatic glycation with new bioanalytical methods

Research paper thumbnail of Measurement of the modification and interference rate of urinary albumin detected by size-exclusion HPLC

Physiological Measurement, 2009

The measurement of the excretion of urinary albumin (albuminuria) is an important and well-establ... more The measurement of the excretion of urinary albumin (albuminuria) is an important and well-established method to assess clinical outcomes. A highperformance liquid chromatography (HPLC) method has been introduced to measure albuminuria. Using this method, it was found that commonly used immunological methods do not measure a fraction of urinary albumin. Some authors presumed that the reason of immuno-unreactivity is the modification of urinary albumin; some others presumed that the difference is merely because of interference. In order to decide this question, we established an HPLC method equipped with tandem UV and fluorescent detection to assess the changes in the detectability of albumin with the rate of modification. For this measurement, differently modified forms of albumin were used. Urine samples of diabetic patients were also measured to find a potential connection between the modification rate and clinical parameters. Secondly, we have established a reversed phase HPLC method to assess the interference rate. We conclude that albumin modification does not affect immunoreactivity. The modification rate of urinary albumin in diabetic patients showed a correlation with renal function. The interference rate of the albumin peak was found to be 12.7% on average, which does not explain the difference between the two methods.

Research paper thumbnail of Detection of the antibacterial effect of essential oils on outer membrane proteins of Pseudomonas aeruginosa by lab-on-a-chip and MALDI-TOF/MS

Flavour and Fragrance Journal, 2013

In bacteria, structural changes of outer membrane protein (OMP) composition may have an effect on... more In bacteria, structural changes of outer membrane protein (OMP) composition may have an effect on the adhesive ability and pathogenic properties of the organisms. Pseudomonas aeruginosa can develop an intrinsic resistance to a wide range of biocides, which is associated with the nature of its outer membrane. The aim of our study was to examine how the essential oils of cinnamon bark and clove modify the OMP composition of the human pathogen P. aeruginosa strains and to identify the structure of proteins that are considerably changed after incubation with essential oils. Chemical composition of the oils was analysed by using gas chromatography and gas chromatography-mass spectrometry. Eugenol (83.7%) was the main component of the clove oil, while trans-cinnamic aldehyde (73.2%) was the main constituent in cinnamon bark oil. Values for the minimum inhibitory concentration (MIC) of the oils were determined by a modified tube dilution method. The oils were administered to the culture at concentrations of 0.5 Â MIC and 2 Â MIC and incubated for 60 min. After OMP preparation, the structure of proteins was analysed by MALDI-TOF/MS. Cinnamon and clove oil could influence the OMP composition of Pseudomonas strains. Proteins with molecular weights of 42.7 kDa and 79.4 kDa disappeared after treatment with cinnamon and clove oil, respectively. Quantitative changes in the protein profile may contribute to the explanation of the antibacterial effect of cinnamon bark and clove essential oils on pathogenic Pseudomonas strains.

Research paper thumbnail of Quantification of Conversion Degree and Monomer Elution from Dental Composite Using HPLC and Micro-Raman Spectroscopy

Chromatographia, 2014

layer increment up to 3 mm from the top led to 10 % decrease in DC and 30-35 % increase in monome... more layer increment up to 3 mm from the top led to 10 % decrease in DC and 30-35 % increase in monomer elution. Further increase in depth from 3 to 4 mm caused 30 % drop in DC and 55 % increase in the amount of leached monomers. The overall result of the findings indicates that direct correlation exists between DC of composite and the elution of unreacted monomers.

Research paper thumbnail of Enrichment of Amadori products derived from the nonenzymatic glycation of proteins using microscale boronate affinity chromatography

Analytical Biochemistry, 2009

Scheme 1. Mechanism of binding and elution processes between cis-diol-containing Amadori peptides... more Scheme 1. Mechanism of binding and elution processes between cis-diol-containing Amadori peptides and boronic acid.

Research paper thumbnail of Synthesis, Pharmacokinetic Characterization and Antioxidant Capacity of Carotenoid Succinates and Their Melatonin Conjugates

Molecules

Carotenoid succinates were synthesized from hydroxy carotenoids and were coupled to a commerciall... more Carotenoid succinates were synthesized from hydroxy carotenoids and were coupled to a commercially available derivative of melatonin via amide bond for producing more powerful anti-oxidants and yet new hybrid lipophilic bifunctional molecules with additional therapeutic effects. The coupling reactions produced conjugates in acceptable to good yields. Succinylation increased the water solubility of the carotenoids, while the conjugation with melatonin resulted in more lipophilic derivatives. The conjugates showed self-assembly in aqueous medium and yielded relatively stable colloidal solutions in phosphate-buffered saline. Antioxidant behavior was measured with ABTS and the FRAP methods for the carotenoids, the carotenoid succinates, and the conjugates with melatonin. A strong dependence on the quality of the solvent was observed. TEAC values of the new derivatives in phosphate-buffered saline were found to be comparable to or higher than those of parent carotenoids, however, synergi...

Research paper thumbnail of Study on the Synthesis, Antioxidant Properties, and Self-Assembly of Carotenoid–Flavonoid Conjugates

Molecules, Feb 1, 2020

Flavonoids and carotenoids possess beneficial physiological effects, such as high antioxidant cap... more Flavonoids and carotenoids possess beneficial physiological effects, such as high antioxidant capacity, anticarcinogenic, immunomodulatory, and anti-inflammatory properties, as well as protective effects against UV light. The covalent coupling of hydrophobic carotenoids with hydrophilic flavonoids, such as daidzein and chrysin, was achieved, resulting in new amphipathic structures. 7-Azidohexyl ethers of daidzein and chrysin were prepared in five steps, and their azide-alkyne [4 + 2] cycloaddition with pentynoates of 8′-apo-β-carotenol, zeaxanthin, and capsanthin afforded carotenoid–flavonoid conjugates. The trolox-equivalent antioxidant capacity against ABTS•+ radical cation and self-assembly of the final products were examined. The 1:1 flavonoid–carotenoid hybrids generally showed higher antioxidant activity than their parent flavonoids but lower than that of the corresponding carotenoids. The diflavonoid hybrids of zeaxanthin and capsanthin, however, were found to exhibit a synergistic enhancement in antioxidant capacities. ECD (electronic circular dichroism) and UV-vis analysis of zeaxanthin–flavonoid conjugates revealed that they form different optically active J-aggregates in acetone/water and tetrahydrofuran/water mixtures depending on the solvent ratio and type of the applied aprotic polar solvent, while the capsanthin derivatives showed no self-assembly. The zeaxanthin bis-triazole conjugates with daidzein and with chrysin, differing only in the position of a phenolic hydroxyl group, showed significantly different aggregation profile upon the addition of water.

Research paper thumbnail of PEPTIDOMIC/PROTEOMIC PROFILING OF HUMAN EMBRYO SECTRETOME

Research paper thumbnail of Potential urinary biomarkers of disease activity in Crohn's disease

Scandinavian Journal of Gastroenterology, 2010

Measurement of the immunoreactive urinary albumin (ir-uAlb) concentration by immunological method... more Measurement of the immunoreactive urinary albumin (ir-uAlb) concentration by immunological methods was found to be an effective method to identify disease activity in Crohn&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease (CD). Recently a size-exclusion (SE) high performance liquid chromatography (HPLC) method was developed to measure both ir-uAlb and non-immunoreactive urinary albumin (total, t-uAlb). We aimed to follow-up one of our CD patients with frequent remissions and exacerbation phases comparing the changes of disease activity parameters and the concentration of ir-uAlb and t-uAlb. The surprising results led us to perform measurements in greater depth. Concentration of ir-uAlb was measured by immunoturbidimetry (IT) and t-uAlb by SE-HPLC. Albumin peak of SE-HPLC was collected and applied to a reversed-phase (RP) HPLC and to gel-electrophoresis. Eluted peaks of RP-HPLC and identified bands of gel-electrophoresis were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). The concentration of t-uAlb was 15 times higher than that of the ir-uAlb during active state. The RP-HPLC and the gel-electrophoresis separation proved that albumin peak by size-exclusion consists of three different peaks. MALDI-TOF/MS measurements identified α1-acid-glycoprotein and Zn-α2-glycoprotein as major, and albumin as minor protein. Peak of albumin of SE-HPLC contains a significant amount of glycoprotein during the active phase of CD, which could not be detected in remission. Urinary α1-acid-glycoprotein and/or Zn-α2-glycoprotein could be an ideal disease activity biomarker of CD.

Research paper thumbnail of Quantification of Conversion Degree and Monomer Elution from Dental Composite Using HPLC and Micro-Raman Spectroscopy

Chromatographia, 2014

layer increment up to 3 mm from the top led to 10 % decrease in DC and 30-35 % increase in monome... more layer increment up to 3 mm from the top led to 10 % decrease in DC and 30-35 % increase in monomer elution. Further increase in depth from 3 to 4 mm caused 30 % drop in DC and 55 % increase in the amount of leached monomers. The overall result of the findings indicates that direct correlation exists between DC of composite and the elution of unreacted monomers.

Research paper thumbnail of Investigation of Phenolic Components of Hungarian Wines

International Journal of Molecular Sciences, 2007

Ninety-two wines from the southernmost wine-producing region in Hungary (Villány) were analyzed f... more Ninety-two wines from the southernmost wine-producing region in Hungary (Villány) were analyzed for their polyphenolic content by high performance liquid chromatography (HPLC). Our results show that wine variety or vintage year could not be distinguished based on polyphenol content, but winery origin could be. Resveratrol concentration is mainly dependent on variety and vintage year. The "human factor" (i.e., winemaking style and technology) seems to be more decisive for the polyphenolic composition of red wines than other factors, such as variety and vintage year.