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1.
J Sci Food Agric ; 101(13): 5419-5428, 2021 Oct.
Article in English | MEDLINE | ID: mdl-33647164

ABSTRACT

BACKGROUND: Pickering emulsions (PEs) which are stabilized by solid particles instead of surfactants have recently attracted tremendous attentions due to their non-toxic and long-term stable nature. In the current study, we fabricated and characterized zein (ZN)/chitosan (CS) complex particles (ZNCSPs) stabilized PE for the encapsulation and delivery of vitamin D3 . RESULTS: The ZNCSPs were synthesized with different ratios, i.e. 1:1, 1:1.5 and 1:2 to investigate the optimum ratio. Transmission electron microscopy observations showed the spherical nature with smooth surface of the obtained particles in the case of ZNCS ratio 1:1.5 and 1:2. Furthermore, ζ-potential values for the these particles were 32.53 ± 1.3 and 52.86 ± 0.68 mV respectively, indicating particles with (1:2) being more stable than 1:1.5. Thereafter, using these particles, the PEs were successfully formulated with different oil (medium chain triglyceride) fractions (330, 500 and 660 g kg-1 ). The emulsions were evaluated for stability during storage and against different environmental factors including pH, temperature and ionic strength on the creaming indices (CIs) of these emulsions. The results demonstrated that the PEs with oil fractions 330 and 500 g kg-1 exhibited significant stability during storage, particularly the ones with 500 g kg-1 oil fractions which were stable against all the tested parameters. Finally, the prepared PEs were evaluated as efficient delivery system by encapsulating and delivering vitamin D3 . In vitro drug release profile confirmed sustained and controlled release of the encapsulated vitamin D3 . CONCLUSION: Overall, our findings suggest that ZNCSPs can be promising stabilizers for stable PEs that can be used as potential delivery systems in food, cosmetic and pharmaceutical industries. © 2021 Society of Chemical Industry.


Subject(s)
Chitosan/chemistry , Cholecalciferol/chemistry , Drug Carriers/chemistry , Zein/chemistry , Drug Compounding , Drug Delivery Systems , Drug Stability , Emulsions/chemistry , Nanoparticles/chemistry , Particle Size
2.
Physiol Res ; 69(Suppl 4): S573-S581, 2020 Dec 31.
Article in English | MEDLINE | ID: mdl-33656905

ABSTRACT

Dihydromyricetin (DHM) is a natural flavonoid showing several health promoting effects such as protective activity during severe alcohol intoxication. The mechanism underlying the effects of DHM on alcohol metabolism is virtually unknown. The present paper is focused on clarifying the role of DHM in the liver alcohol elimination at its molecular level. First, impact of DHM on alcohol dehydrogenase (ADH) activity in vitro and the enzyme induction in vivo was examined. Neither the ADH activity nor the enzyme expression were influenced by DHM. Next, the effect of DHM during alcohol intoxication were studied on primary hepatocytes isolated from EtOH-premedicated and untreated rats. The viability of cells exposed to alcohol, estimated based on the released enzymes, alanine aminotransferase (ALT) and aspartate aminotransferase (AST), was slightly affected by DHM. Although the expected hepatoprotective effect of DHM was not fully achieved, DHM (in a concentration manner) proved to reduce the level of ROS/RNS in hepatocytes. However, no change in the rate of alcohol metabolism in vivo was found when rats were administered with a single or repeated dose of ethanol supplemented with DHM. In conclusion, the proposed positive effect of DHM during alcohol intoxication has not been proven. Moreover, there is no effect of DHM on the alcohol metabolism. The "hoped-for" DHM hepatoprotective activity can be attributed to the reduction of ROS/RNS levels in cells.


Subject(s)
Antioxidants/pharmacology , Ethanol/metabolism , Flavonols/pharmacology , Hepatocytes/drug effects , Liver/drug effects , Alcohol Dehydrogenase/metabolism , Animals , Cells, Cultured , Cytochrome P-450 CYP2E1/metabolism , Hepatocytes/metabolism , Inactivation, Metabolic , Liver/metabolism , Male , Nitrosative Stress/drug effects , Oxidative Stress/drug effects , Rats, Wistar , Reactive Nitrogen Species/metabolism , Reactive Oxygen Species/metabolism
3.
Physiol Res ; 66(Suppl 1): S129-S137, 2017 04 05.
Article in English | MEDLINE | ID: mdl-28379038

ABSTRACT

Our previous study showed that a diet enriched with 400 g of carp per week improved plasma lipids in subjects after aortocoronary bypass (CABG). The aim of the present study is to determine whether the different carp farming systems have an impact on the effects of carp meat in secondary cardiovascular prevention. We examined 3 groups of patients after CABG over a 4-week period of spa treatment (108 persons, 73 males, 35 females, age over 60 years). We found no differences in baseline values of blood pressure or plasma lipids. The patients were given a standard spa diet (controls; N=36) or a diet enriched of 400 g of carp meat per week, enriched omega 3 (N=37) or cereal carp (N=35). Plasma lipid parameters were examined at start and after 4 weeks in a routine laboratory setting. Group consuming omega-3 carp showed the largest decline in total cholesterol, LDL cholesterol, triglycerides and an increase in HDL cholesterol (all p<0.01). We found that carp meat from the two production systems showed significantly different effects on plasma lipids. Further trials should be performed to clarify the exact causes of the differences.


Subject(s)
Aquaculture/methods , Carps , Fatty Acids, Omega-3/administration & dosage , Feeding Behavior , Myocardial Ischemia/diet therapy , Secondary Prevention/methods , Aged , Animals , Female , Follow-Up Studies , Humans , Male , Middle Aged , Myocardial Ischemia/blood , Myocardial Ischemia/epidemiology
5.
Fish Physiol Biochem ; 35(4): 615-23, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19043793

ABSTRACT

Common carp (Cyprinus carpio) is, globally, one of the most important farmed fish species. We have analyzed carp from a natural pond-production system in South Bohemia. Ongrowing fish had access to an abundant plankton population which was supplemented with cereals. Fatty acid composition (FA) was investigated in three parts of fillets from four crosses of carp. The FA composition of the leanest part, the dorsal white muscle was similar to that of marine-farmed species; it contained a large proportion of n-3 highly unsaturated FA, the n-3/n-6 ratio was 1.1, and the proportion of phospholipids was high. The abdominal wall is rich in monounsaturated FA, the n-3/n-6 ratio is lower, 0.5, and it is more affected by the cereal feed. We concluded that the lipid composition of all these carp tissues can be improved in terms of healthy FA profile.


Subject(s)
Carps/metabolism , Lipids/analysis , Meat/analysis , Muscle, Skeletal/chemistry , Analysis of Variance , Animals , Aquaculture , Chromatography, Gas , Chromatography, Thin Layer , Crosses, Genetic , Czech Republic
6.
Toxicol Lett ; 162(2-3): 211-8, 2006 Apr 10.
Article in English | MEDLINE | ID: mdl-16289959

ABSTRACT

Metabolism of the solvents N,N-dimethylformamide (DMF) and N-methylformamide (MF) results in the formation of N-methylcarbamoyl adducts at the N-terminal valine and lysine in blood protein globin, of which the lysine adduct has so far only been reported in rats given high doses of both solvents [Mráz, J., Simek, P., Chvalová, D., Nohová, H., Smigolová, P., 2004. Studies on the methyl isocyanate adducts in globin. Chem. Biol. Interact. 148, 1-10]. Here we examined whether the lysine adduct is produced, and accessible to analysis, in humans occupationally or experimentally exposed to DMF. Globin from exposed subjects (n=35) and unexposed controls (n=5) was analyzed by two methods. Edman degradation was used as a sensitive reference method to measure the valine adduct by converting it to 3-methyl-5-isopropylhydantoin (MVH). The MVH levels in globin of the exposed subjects were in the range of 1-441 nmol/g, in controls <1 nmol/g. The principal method of globin analysis consisted of enzymatic hydrolysis with pronase to release free N(epsilon)-(N-methylcarbamoyl)lysine (MLU) and N-methylcarbamoylvaline (MVU), which were determined by HPLC/MS/MS, with no clean-up or preconcentration steps needed. For MLU, the parent and product ions were m/z 204-->173, and the limit of detection was approximately 5 nmol/g globin. MLU was found in most globins from the exposed subjects but not in the controls. A close correlation between the MLU and MVH levels (nmol/g) was observed: MLU=7+0.48 MVH (R(2)=0.84, n=32). In conclusion, MLU can be easily measured in globin of workers exposed to DMF. The findings also indicate a long-term persistence of MLU in the human body, and consequently, its potential as a biomarker of chronic exposure to DMF.


Subject(s)
Dimethylformamide/metabolism , Globins/metabolism , Lysine/metabolism , Biomarkers , Humans , Hydantoins/metabolism , Lysine/analogs & derivatives , Occupational Exposure/analysis , Protein Binding
7.
Int Arch Occup Environ Health ; 77(6): 427-32, 2004 Aug.
Article in English | MEDLINE | ID: mdl-15309551

ABSTRACT

AIM: To assess the suitability of different methods for biological monitoring of internal dose to N,N-dimethylformamide (DMF) in occupational settings. METHODS: The determination of urinary metabolites of DMF, N-hydroxymethyl- N-methylformamide (HMMF), N-methylformamide (NMF) and N-acetyl- S-(N-methylcarbamoyl) cysteine (AMCC) was carried out by four selected analytical procedures. Two methods solely measured total NMF (HMMF and NMF). The other two methods measured both total NMF and AMCC in one analytical run. All four methods were tested on 34 urine samples from workers exposed to DMF. RESULTS: Comparison of the four methods for determination of total NMF in urine showed that results were similar for three methods, while the remaining one provided NMF levels significantly lower (by 22%) than the other methods. Thus, all but one of the tested methods for the determination of total NMF can be considered to be suitable for biological monitoring of internal dose to DMF. The two tested methods for the determination of AMCC afforded results that showed high correlation but differed significantly (by 10%). CONCLUSION: The choice of the biomonitoring method depends mainly on the purpose for which the measurement is conducted. For evaluation of acute exposures or to assess safety measures in the working area, an updated version of the traditional method of Kimmerle and Eben (1975a, b) for the determination of total NMF in urine is sufficient. For risk assessment after exposure to DMF, the determination of AMCC should be carried out, since AMCC, but not total NMF, is supposed to be related to the toxicity of DMF. However, there is still a need to develop an easier, more sensitive and more selective method for the determination of AMCC in urine until AMCC can be considered for regulatory purposes in occupational settings.


Subject(s)
Acetylcysteine/analogs & derivatives , Chemical Industry , Dimethylformamide/analogs & derivatives , Dimethylformamide/isolation & purification , Environmental Monitoring/methods , Occupational Exposure/analysis , Urinalysis/methods , Acetylcysteine/analysis , Acetylcysteine/metabolism , Biotransformation , Chromatography, Gas , Dimethylformamide/analysis , Dimethylformamide/metabolism , Formamides/analysis , Formamides/metabolism , Humans , Male , Occupational Health , Risk Assessment
8.
Chem Biol Interact ; 148(1-2): 1-10, 2004 Jun 30.
Article in English | MEDLINE | ID: mdl-15223351

ABSTRACT

Isocyanates such as methylisocyanate (MIC), an intermediate in the synthesis of carbamate pesticides, or diisocyanates, used in the production of plastics, are highly reactive toxic compounds that spontaneously bind to biological macromolecules. In vivo formation of stable adducts with blood protein globin offers possibilities for biomonitoring of internal exposure to various reactive species. Thus, biomonitoring of the isocyanates through determination of their specific adducts with globin is a challenge. In this study, we characterized the adducts formed in human globin upon treatment with 100-fold molar excess of MIC. The globin was subject to enzymatic hydrolysis with pronase, and the hydrolysate was analysed by high performance liquid chromatography with positive atmospheric pressure chemical ionization mass spectrometric detection (HPLC/APCI-MS). The two major MIC adducts were those with N-terminal Val and side-chain of Lys, as confirmed by comparison with the synthetic standards. About 20 other adducts were observed, and several of them were tentatively identified using their MS and MS/MS spectra. Whereas detection of the adducts with Tyr and His was expected, the adducts with Trp and Phe, and a Lys adduct containing two MIC moieties, were probably analytical artifacts resulting from the transcarbamoylation during globin hydrolysis rather than products of direct carbamoylation. The other detected products were MIC-Val-His, derived from the N-terminal dipeptide of globin beta-chain, and dipeptides consisting of MIC-Lys attached to Gly, Val, Leu, Thr, and Glu. Failure to detect the corresponding non-modified dipeptides suggests that the pronase action may be hampered by the amino acid modification. MIC is known as a metabolic intermediate of the industrial solvents N,N-dimethylformamide (DMF) and N-methylformamide (MF) in humans and rats. The HPLC/APCI-MS analysis of globin from rats injected with DMF or MF, 1000 mg/kg, revealed the presence of the MIC adducts with both Val and Lys. The level of the Val adduct in globin from the DMF-dosed rats, determined using Edman degradation and GC/MS, was ca. 40 nmol/g, which is a level common in workers occupationally exposed to DMF. This suggests that also the Lys adduct in such human globin samples can be feasible to analysis and is therefore considered for further studies as a potential biomarker of exposure to DMF.


Subject(s)
Environmental Monitoring/methods , Globins/chemistry , Isocyanates/chemistry , Lysine/chemistry , Valine/chemistry , Animals , Biomarkers/analysis , Chromatography, High Pressure Liquid , Dimethylformamide/pharmacokinetics , Erythrocytes/chemistry , Erythrocytes/metabolism , Formamides/pharmacokinetics , Globins/metabolism , Humans , Hydrolysis , Isocyanates/metabolism , Lysine/metabolism , Pronase/chemistry , Rats , Spectrometry, Mass, Electrospray Ionization , Valine/metabolism
9.
Amino Acids ; 22(1): 95-108, 2002.
Article in English | MEDLINE | ID: mdl-12025876

ABSTRACT

The mechanism by which glutamine produces a favorable effect in the treatment of sepsis, injury, burns and abdominal irradiation is not completely understood. The main aim of this study was to evaluate the effect of alanyl-glutamine (AlaGln) administration on the metabolism of proteins in irradiated rats. The rats were exposed to whole-body irradiation (8Gy) and then fed intragastrically with a mixture of glucose and amino acids either with AlaGln or without AlaGln. At 48 hours after irradiation, parameters of whole-body protein metabolism and DNA synthesis in intestinal mucosa were investigated using a primed, continuous infusion of [1-14C]leucine and [3H]thymidine. In addition, we evaluated the effect of irradiation and AlaGln on gut morphology, blood count and amino acid concentrations in blood plasma and skeletal muscle. Control rats were not irradiated but were given identical treatment. An increase in whole-body leucine oxidation, and insignificant changes in whole-body proteolysis and in protein synthesis were observed after irradiation. In irradiated rats we observed a decrease in muscle glutamine concentration, a decrease in protein synthesis in jejunum, colon and heart, and an increase in synthesis of proteins of blood plasma and spleen. Morphological examination and measurement of DNA synthesis failed to demonstrate any favorable effect of AlaGln supplementation on irradiated gut. However, administration of AlaGln resulted in a decrease in whole-body proteolysis and leucine oxidation which caused an increase in the fraction of leucine incorporated into the pool of body proteins. We conclude that the data obtained demonstrate that irradiation induces metabolic derangement associated with increased oxidation of essential branched-chain amino acids (valine, leucine and isoleucine) and that these disturbances can be ameliorated by administration of AlaGln.


Subject(s)
Dipeptides/pharmacology , Leucine/metabolism , Proteins/metabolism , Whole-Body Irradiation , Amino Acids/blood , Amino Acids/metabolism , Animals , Male , Rats , Rats, Wistar
10.
Soud Lek ; 45(4): 54-6, 2000 Oct.
Article in Czech | MEDLINE | ID: mdl-11378913

ABSTRACT

During a check-up of a driver by a police patrol in the Czech Republic by means of a breath analyzer of Dräger Co. an alcohol blood level of 0.50 g/kg was assessed. Later the driver reported that before the test he used at 30- and 5-minute intervals the drug Stopangin spray. In the Institute of Forensic Medicine the authors made an experiment which revealed that 22 minutes after administration of the drug the apparatus gave a negative result. Agreement with these conclusions was expressed also by a representative of Dräger Co. and the results were published as an expert opinion with a recommended procedure for the police of the Czech Republic in the South Moravian region.


Subject(s)
Alcoholic Intoxication/diagnosis , Breath Tests/instrumentation , Ethanol/blood , Pharyngitis/drug therapy , Aerosols , Alcoholic Intoxication/blood , Ethanol/therapeutic use , Humans , Male
11.
Scand J Work Environ Health ; 25(3): 233-7, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10450774

ABSTRACT

OBJECTIVES: This study explored the acute effect of ethanol (EtOH) on the urinary excretion of cyclohexanol (CH-ol), 1,2- and 1,4-cyclohexanediol (CH-diol), biomarkers of exposure to important solvents, and chemical intermediates cyclohexanone (CH-one), cyclohexane (CH) and cyclohexanol. METHODS: Volunteers (5-8 in each group) were exposed for 8 hours either to CH-one, CH or CH-ol vapor at concentrations of about 200, 1000, and 200 mg/m3, respectively, with concomitant ingestion of EtOH (4 14-g doses taken during the exposure). Urine was collected for 72 hours and analyzed for CH-ol and CH-diols using a procedure involving acidic hydrolysis and gas chromatographic determination. RESULTS: The metabolic yields of CH-ol, 1,2-, and 1,4-CH-diol, respectively, in the exposures with EtOH were as follows: 11.3%, 36%, 23% after the exposure to CH-one, 3.1%, 15%, 8% after the exposure to CH, and 6.6%, 24%, 18% after the exposure to CH-ol. [The corresponding values obtained previously in matching experiments without EtOH were as follows: 1.0%, 39%, 18% (CH-one); 0.5%, 23%, 11% (CH); and 1.1%, 19%, 8% (CH-ol).] The excretion curves of the metabolites in the exposures with EtOH were not delayed when compared with the corresponding curves of a comparison group. CONCLUSIONS: The urinary excretion of CH-diols is much less sensitive to EtOH than that of CH-ol. It is recommended to employ CH-diols as useful and more reliable biomarkers of exposure to CH-one, CH and CH-ol in field examinations.


Subject(s)
Cyclohexanols/urine , Ethanol/pharmacokinetics , Adult , Alcoholic Beverages , Biomarkers , Female , Humans , Male , Middle Aged
12.
Arch Toxicol ; 73(1): 33-40, 1999 Feb.
Article in English | MEDLINE | ID: mdl-10207612

ABSTRACT

In human liver microsomes the oxidations of benzene, chlorzoxazone, aniline, dimethylformamide, and 4-nitrophenol were significantly correlated with each other and with the level of cytochrome P450 (CYP) 2E1 estimated by immunoblotting. Moreover, benzene oxidation to water-soluble metabolites was suppressed by 0.1 mM diethyldithiocarbamate, supposedly a specific inhibitor of CYP2E1 at this level. None of these metabolic rates correlated with immunochemically determined levels of CYP1A2, 2C9, and 3A4 nor oxidation of 7-ethoxyresorufin, tolbutamide, and nifedipine. Benzene oxidation to water-soluble metabolites was characterized by typical Michaelis-Menten kinetics. The different benzene K(m) values seen in individual human microsomal samples were not correlated with the level or activity of CYP1A2, 2C9, 2E1, and 3A4 but could be due to CYP2E1 microheterogeneity. The lowest K(m) for benzene oxidation could be related to C/D and/or c1/c2 polymorphism of CYP2E1 gene. Covalent binding of benzene reactive metabolites to microsomal proteins was also correlated with the CYP2E1 metabolic rates and immunochemical levels. At high concentrations of benzene covalent binding was inversely related to benzene concentrations (as well as to formation of water-soluble metabolites) in agreement with the view that secondary metabolites, mainly benzoquinone, are responsible for the covalent binding.


Subject(s)
Benzene/metabolism , Microsomes, Liver/metabolism , Carbon Radioisotopes , Chelating Agents/pharmacology , Cytochrome P-450 CYP2E1/biosynthesis , Cytochrome P-450 CYP2E1/drug effects , Cytochrome P-450 CYP2E1/genetics , Ditiocarb/analogs & derivatives , Ditiocarb/pharmacology , Genotype , Glutathione/pharmacology , Humans , Immunoblotting , Kinetics , Methane/pharmacology , Microsomes, Liver/chemistry , Microsomes, Liver/drug effects , Oxidation-Reduction , Solubility , Substrate Specificity , Water
13.
Chem Biol Interact ; 117(2): 173-86, 1999 Jan 29.
Article in English | MEDLINE | ID: mdl-10190575

ABSTRACT

Diisocyanates, reactive compounds used in plastics industry and potent occupational allergens, readily bind to proteins both in vitro and in vivo, however, the pattern of adducts with individual amino acids has not been investigated systematically. In this study, potential of the proteinogenic amino acid residues for carbamoylation with 2,4-toluenediisocyanate (2,4-TDI) and hexamethylenediisocyanate (HDI) was evaluated. The diisocyanates were incubated in an in vitro system (buffer pH 7.4/dioxane 50:50) with: (a) a series of Nalpha-benzyloxycarbonyl amino acids (Z-amino acids) and N-acetylcysteine (Ac-Cys), model compounds for non-N-terminal amino acids of the protein chain; (b) dipeptides Val-Phe and Asp-Phe, model compounds for N-termini of globin and albumin, respectively. Reactivity of the compounds tested, evaluated from their depletion during incubation with the diisocyanates (measured by HPLC), was in the order: Ac-Cys = Asp-Phe > Val-Phe = Nalpha-Z-Lys >> Nalpha-Z-His for 2,4-TDI, and Ac-Cys > Asp-Phe > Val-Phe = Nalpha-Z-Lys > Nalpha-Z-His > N-Z-Tyr for HDI, however, the adducts with Ac-Cys were unstable. Reactions of other amino acid residues (e.g. Ser, Thr, Met, Trp, Arg, Asn, Gln) with 2,4-TDI and HDI were not observed. Thus, N-terminal amino acids and Lys residues are likely to produce most abundant adducts with diisocyanates in proteins. Further, three amino compounds with increasing pKa values (Val-Phe, Val and Nalpha-Z-Lys) were incubated with 2,4-TDI and N-acetyl-S-[4-(2-amino)tolylcarbamoyl]cysteine, a 2,4-TDI-derived thiocarbamate with carbamoylating activity, in media with 10% and no dioxane, respectively. Here, reactivity of the amino compounds was decreasing in the order: Val-Phe > Val > Nalpha-Z-Lys, which reflects the mechanism of the amine-isocyanate reaction. The experiments also demonstrate the effect of a solvent (organic phase content) on the yield of the carbamoylation reactions.


Subject(s)
Amino Acids/metabolism , Blood Proteins/metabolism , Cyanates/metabolism , Toluene 2,4-Diisocyanate/metabolism , Albumins/chemistry , Amino Acids/chemistry , Blood Proteins/chemistry , Chromatography, High Pressure Liquid , Chromatography, Thin Layer , Globins/chemistry , In Vitro Techniques , Isocyanates , Toluene 2,4-Diisocyanate/chemistry
14.
Amino Acids ; 16(1): 1-11, 1999.
Article in English | MEDLINE | ID: mdl-10078329

ABSTRACT

The aims of the present study were to assess the changes of individual plasma amino acid levels in relation (1) to the severity of liver damage and (2) to the process of liver recovery. Acute liver injury was induced by an intragastric administration of CCl4 diluted in olive oil in doses of 2, 4 and/or 6 g of CCl4 per kg b.w. The control rats received olive oil only. Animals were sacrificed at 16, 24, 48 and 96 hours after treatment. The severity of liver injury was assessed by histological examination, by changes in ALT and AST in the blood plasma and by changes in liver weight. Statistical analysis was carried by ANOVA, p < 0.05 was considered significant. The Spearman rank correlation coefficient was used as a measure of the degree of linear relationship between variable and dose. In the period of the development of acute liver damage, i.e. at 16 and 24 hours after treatment, an increase in blood plasma amino acid levels and positive correlations with the dose of CCl4 were observed for most individual amino acids. The only exception was arginine which decreased in a dose dependent manner. At a phase of liver recovery, i.e. at 48 and 96 hours after CCl4 treatment, the concentrations of some individual amino acids decreased below the control values. The negative correlation with the dose of CCl4 occurred for taurine and isoleucine (at 48 hours) and taurine, threonine, valine, methionine, isoleucine and leucine (at 96 hours).


Subject(s)
Amino Acids/blood , Carbon Tetrachloride Poisoning/blood , Chemical and Drug Induced Liver Injury/blood , Acute Disease , Alanine Transaminase/blood , Animals , Aspartate Aminotransferases/blood , Carbon Tetrachloride Poisoning/pathology , Chemical and Drug Induced Liver Injury/pathology , Dose-Response Relationship, Drug , Male , Organ Size , Rats , Rats, Wistar
15.
Soud Lek ; 44(4): 47-54, 1999 Oct.
Article in Czech | MEDLINE | ID: mdl-10677917

ABSTRACT

Paper concerns the alcohol contents of beer now produced. The previous and contemporary ways of beer signing as well as a complete list of beer sorts produced in the Czech Republic is presented.


Subject(s)
Beer/analysis , Ethanol/analysis , Czech Republic
16.
Int Arch Occup Environ Health ; 71(8): 560-5, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9860166

ABSTRACT

The metabolism and toxicokinetics of cyclohexane (CH) and cyclohexanol (CH-ol), important solvents and chemical intermediates, were studied in volunteers after 8-h periods of inhalation exposure at concentrations of 1010 and 236 mg m(-3), respectively (occupational exposure limits: CH, 1050 mg m(-3); CH-ol, 200 mg m(-3)). Of the dose of absorbed parent compounds, the yields of urinary CH-ol and 1,2- and 1,4-cyclohexanediol (CH-diol) were 0.5%, 23.4%, and 11.3%, respectively, after exposure to CH and 1.1%, 19.1%, and 8.4%, respectively, after exposure to CH-ol as determined by a gas chromatography method involving hydrolysis of glucuronide conjugates. The metabolic patterns of CH and CH-ol were very similar to that of cyclohexanone (CH-one) studied in the laboratory previously. For all three compounds, peak excretion of CH-ol occurred at the end of the exposure period, after which it decayed rapidly. Excretion curves of 1,2- and 1,4-CH-diol reached maximal values within 0-6 h postexposure, with subsequent elimination half-lives being 14-18 h. The rate-limiting step in the elimination of CH compounds from the organism is renal clearance of CH-diols. Determination of CH-diols in end-of-shift urine samples is recommended as a useful new method of biomonitoring of CH, CH-ol, and CH-one at the workplace. However, due to accumulation of CH-diols in the body during repeated exposure, quantitative relationships between the exposure and the level of CH-diols have to be adjusted according to the day of sampling during the working week.


Subject(s)
Cyclohexanes/pharmacokinetics , Cyclohexanols/pharmacokinetics , Cyclohexanols/urine , Cyclohexanones/pharmacokinetics , Adult , Biomarkers/analysis , Chromatography, Gas , Environmental Monitoring/methods , Female , Half-Life , Humans , Inhalation Exposure , Male , Middle Aged
17.
Toxicol Lett ; 90(2-3): 199-205, 1997 Feb 07.
Article in English | MEDLINE | ID: mdl-9067488

ABSTRACT

Male Wistar rats were dosed intraperitoneally with styrene (400 mg/kg). Urine samples were collected over phosphate buffer, pH 6.5 for 24 h. Excretion of mandelic (MA) and phenylglyoxylic acid (PGA) amounted to 1.66 +/- 0.62 and 5.21 +/- 2.44% of dose, respectively, as determined by ion-pair HPLC. After acidic hydrolysis, the amount of MA and PGA found in urine increased to 2.10 +/- 0.84 and 6.81 +/- 3.20% (mean +/- S.D.; n = 7), respectively. A similar increase was observed after alkaline hydrolysis of urine samples. Differences between hydrolysed and non-hydrolysed samples were significant in the paired t-test (P < 0.05). Further, urine samples were fractionated by HPLC. Fractions were subjected to acidic hydrolysis and analysed by HPLC and GC/MS. Both MA and PGA were detected in the fraction which did not contain any of these metabolites before hydrolytic treatment. Thus, MA and PGA, which are used as biomarkers of exposure to styrene, form hydrolysable conjugates in the rat. At least a minor part of the total urinary MA and PGA is bound in these conjugates.


Subject(s)
Glyoxylates/metabolism , Glyoxylates/urine , Mandelic Acids/metabolism , Mandelic Acids/urine , Styrenes/toxicity , Animals , Biopolymers/urine , Gas Chromatography-Mass Spectrometry , Glyoxylates/chemistry , Injections, Intraperitoneal , Male , Mandelic Acids/chemistry , Proteinuria/urine , Rats , Rats, Wistar , Styrene , Styrenes/pharmacokinetics
18.
Int J Clin Pharmacol Ther ; 34(1): 38-42, 1996 Jan.
Article in English | MEDLINE | ID: mdl-8688995

ABSTRACT

Oxidative phenotype P-450 2D6 was examined using sparteine test in 3 groups of persons to determine if there is a coincidence in the defect of the oxidative biotransformation of sparteine and impaired oxidation of toluene, which could explain interindividual differences in the amounts of hippuric acid in the urine in exposed persons. The following groups of persons were examined: 30 rotogravure printers exposed to toluene vapors at concentrations of 8-307 ppm; 20 workers, 2 months after the cessation of the long-term exposure to toluene at concentrations of 104-1,170 ppm; 48 healthy volunteers with no exposure to toluene. Among the 98 persons 5 poor metabolizers (PMs) of sparteine were found, none in the group of printers exposed to toluene. In the experimental exposure chamber 5 PMs and 6 extensive metabolizers (EMs) were exposed to toluene concentration of 245 ppm for 5 hours. Hippuric acid and o-cresol in the urine, and toluene both in blood and in alveolar air were measured. However, no significant differences were found in either of these parameters between the PM and EM groups. Thus, the sparteine test does not appear to be applicable in the identification of persons with higher risk arising from toluene exposure.


Subject(s)
Cytochrome P-450 Enzyme System/metabolism , Mixed Function Oxygenases/metabolism , Toluene/metabolism , Adult , Animals , Biotransformation , Cresols/urine , Cytochrome P-450 CYP2D6 , Hippurates/urine , Humans , Occupational Exposure , Oxidation-Reduction , Oxytocics/metabolism , Oxytocics/urine , Phenotype , Polymorphism, Genetic , Rats , Sparteine/metabolism , Sparteine/urine , Toluene/urine , Xenobiotics/metabolism
19.
Amino Acids ; 10(3): 229-41, 1996 Sep.
Article in English | MEDLINE | ID: mdl-24178537

ABSTRACT

We studied the plasma amino acid profiles in four models of hepatic injury in rats. In partially hepatectomized rats (65% of liver was removed) we observed significant increase of aromatic amino acids (AAA; i.e. tyrosine and phenylalanine), taurine, aspartate, threonine, serine, asparagine, methionine, ornithine and histidine. Branched-chain amino acids (BCAA; i.e. valine, leucine and isoleucine) concentrations were unchanged. In ischemic and carbon tetrachloride acute liver damage we observed extreme elevation of most of amino acids (BCAA included) and very low concentration of arginine. In carbon tetrachloride induced liver cirrhosis we observed increased levels of AAA, aspartate, asparagine, methionine, ornithine and histidine and decrease of BCAA, threonine and cystine. BCAA/AAA ratio decreased significantly in partially hepatectomized and cirrhotic rats and was unchanged in ischemic and acute carbon tetrachloride liver damage. We conclude that a high increase of most of amino acids is characteristic of fulminant hepatic necrosis; decreased BCAA/AAA ratio is characteristic of liver cirrhosis; and decrease of BCAA/AAA ratio may not be used as an indicator of the severity of hepatic parenchymal damage.

20.
Rozhl Chir ; 74(8): 389-91, 1995 Dec.
Article in Czech | MEDLINE | ID: mdl-8629169

ABSTRACT

Dilatation of distal urethral stenoses is one of the relatively frequent minor operations in child urology. The authors present a group of 830 female patients age 2-16 years treated by dilatation of the urethra in 1988-1994. According to the predominating finding they divide the cases into three groups--vesicoureteral reflux (VUR), infection of the urinary pathways (IUP), enuresis--and in these they evaluate the effectiveness of the operation, which was greatest in the group of patients with IUP (37%). Finally they discuss both possibilities of treatment of stenoses--dilatation and urethrotomy.


Subject(s)
Urethral Stricture/therapy , Adolescent , Child , Child, Preschool , Dilatation , Enuresis/etiology , Female , Humans , Retrospective Studies , Urethral Stricture/complications , Urinary Tract Infections/etiology , Vesico-Ureteral Reflux/etiology
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