The electrochemical behavior of the herbicide prometryne was studied in aqueous solutions by DC p... more The electrochemical behavior of the herbicide prometryne was studied in aqueous solutions by DC polarography, differential pulse and cyclic voltammetry and by constant potential coulometry. Only the protonated form of prometryne can be reduced at pH < 6.5. The electrode process includes two irreversible steps. The two-electron reduction of the C–S bond leads to its splitting and a release of methylthiol molecule. The triazine ring of the reduction product is immediately reduced under the uptake of two electrons. Both the intermediate and final products of constant potential electrolysis were identified using chromatographic techniques and mass spectrometric analysis. The reduction mechanism of other 2-methylthio-4,6-dialkylamino-s-triazines is identical.
Direct oral anticoagulants are an alternative to anticoagulants based on vitamin K antagonists. M... more Direct oral anticoagulants are an alternative to anticoagulants based on vitamin K antagonists. Monitoring of direct oral anticoagulant concentration levels is necessary in specific cases only (e.g., emergency conditions, determination of the cause of bleeding, adverse effects, risk of drug-direct oral anticoagulants interaction); therefore, a sensitive and specific method is needed. Methanol protein precipitation method followed by liquid chromatography with high-resolution mass spectrometry was developed for simultaneous separation and determination of apixaban, betrixaban, edoxaban, dabigatran, rivaroxaban, and ximelagatran. The proposed method was fully validated in terms of linearity, the limits of detection and quantification, intra- and inter-day trueness and precision, recovery, matrix effect, process efficiency, and stability. The method shows a strong correlation (Pearson's correlation coefficients higher than 0.92) with coagulation assays of apixaban, dabigatran, and rivaroxaban (dTT for gatrans and antiXa activity for xabans). In addition, the developed method was applied for the identification and determination of apixaban and dabigatran in post-mortem serum samples. The developed method is a good alternative to coagulation tests which, however, may show various interferences.
Targeting the aryl hydrocarbon receptor (AhR) is an emerging therapeutic strategy for multiple di... more Targeting the aryl hydrocarbon receptor (AhR) is an emerging therapeutic strategy for multiple diseases (e.g., inflammatory bowel disease). Thermosporothrix hazakensis microbial metabolite 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) is a putative AhR endogenous ligand. To improve the chemical stability, we synthesized a series of ITE chemical mimics. Using a series of in vitro assays, we identified 2-(1H-indole-3-carbonyl)-N-methyl thiazole-4-carboxamide (ITE-CONHCH3) as a highly potent (EC50 = 1.6 nM) AhR agonist with high affinity (Ki = 88 nM). ITE-CONHCH3 triggered AhR nuclear translocation and dimerization of AhR-ARNT, enhanced AhR binding in the CYP1A1 promoter, and induced AhR-regulated genes in an AhR-dependent manner. The metabolic stability of ITE-CONHCH3 in a cell culture was 10 times higher than that of ITE. Finally, we observed protective effects of ITE-CONHCH3 in mice with DSS-induced colitis. Overall, we demonstrate and validate a concept of microbial metabolite mimicry in the therapeutic targeting of AhR.
Publikace Soudni lekařstvi I tvoři prvni dil uceleneho souhrnu nejmodernějsich informaci v oblast... more Publikace Soudni lekařstvi I tvoři prvni dil uceleneho souhrnu nejmodernějsich informaci v oblasti medicinských forenznich věd. Organicky navazuje na ucebnici doc. Vorla, vydanou ovsem před vice než 20 lety (1993), ktera je stale chapana jako volne pokracovani ucebnice prof. Tesaře (prvni vydani 1975). Text, na němž se podileli odbornici ze vsech soudnělekařských zařizeni v CR a castecně i z.e Slovenska, je sice urcen v prvni řadě soudnim lekařům, ale užitecne informace v něm najdou i dalsi obory, a to nejen medicinske a pravni. Prvni dil obsahuje 18 kapitol pocinaje historii soudniho lekařstvi jako jednoho z nejstarsich lekařských oborů v Ceske republice. K. nutnemu vzdělani soucasných lekařů neodmyslitelně patři i gramotnost pravni. To je obsahem 2. a 5. kapitoly. V dalsich kapitolach je podrobně rozebrana obecna problematika smrti, vcetně posmrtných změn, urcovani doby smrti a vitality poraněni. Svoji multioborovost prokazuje soudni lekařstvi zejmena v kapitole 6 Identifikace oso...
Objective: There is limited information about long term variability of patient compliance to anti... more Objective: There is limited information about long term variability of patient compliance to antihypertensive medication. The aim of our study was to evaluate changes in long term compliance in patients with resistant arterial hypertension taking beta-blockers. Design and method: Population and Methods: The serum levels of the prescribed beta-blockers were repeatedly evaluated in patients treated in our department for resistant arterial hypertension. The minimum time difference between single measurements in one patient was 3 month. If the serum level of the prescribed beta-blocker was within therapeutic range, patient was regarded as compliant at the particular visit. If the serum level was subtherapeutic or the beta-blocker was not present in serum at all, patient was regarded as noncompliant. Results: In 39 patients (56% men) we performed total of 146 measurements of serum beta-blocker level with average of 3.74 (±1.56) measurements per each patient. Mean baseline blood pressure ...
The phenolic composition of the aerial parts and corms of C. bornmuelleri, C. kotschyi, C. macrop... more The phenolic composition of the aerial parts and corms of C. bornmuelleri, C. kotschyi, C. macrophyllum and C. speciosum were analysed by capillary GC or GC-MS and twenty-three phenolics were identified. The phenolic fractions were tested for their cytoprotective effect on tBH-induced injury on isolated rat hepatocytes. The results indicate that phenotic fractions from leaves and flowers and the main constituent luteolin reduced the tBH-induced LPX and leakage of LDH. In contrast, phenolic fractions from seeds, not containing luteolin, had no significant effect on LDH though a decrease in LPx was observed.
The article presents the possibilities of identification of selected antidepressants of new gener... more The article presents the possibilities of identification of selected antidepressants of new generations in biological materials. Identification of the drugs by TLC and GC-MS after ether extraction from biological materials (urine, stomach content) was tested. The detection is sensitive and reliable for most of the drugs. For quantitative GC-MS analysis, the drugs were isolated from blood or serum by solid phase extraction (SPE). The recovery of most drugs is over 70 %. Limits of detection (LOD, 3 S/N) as well as limits of quantification (LOQ, 10 S/N) have been determined. The LOD are 0.5−2 ng l−1 for citalopram, maprotiline, mianserine, mirtazapine, moclobemide, sertraline and venlafaxine, 15 ng l−1 for fluoxetine and milnacipran and 50 ng l−1 for fluvoxamine, paroxetine and trazodone. LOQ are 2−5 ng l−1 for citalopram, maprotiline, mianserine, mirtazapine, moclobemide, sertraline and venlafaxine, 50 ng l−1 for fluoxetine and milnacipran and 100 ng l−1 for fluvoxamine, paroxetine an...
Alcohol abuse is related to a wide variety of negative health outcomes including mortality in old... more Alcohol abuse is related to a wide variety of negative health outcomes including mortality in older people. Alcohol abuse in older people is characterised by certain specific features uncommon in general adult population. The main objective of this study was to analyse the autopsy protocols of deceased older people in relation to blood alcohol concentration (BAC), sex, age, and manner of death. As a positive BAC, >0.20 g/kg was accepted. The sample consists of 1,012 deceased older people (i.e. aged 65 years and over) selected out of 2,377 autopsied subjects in the period from 2003–2013. Subjects included into the sample were chosen via the proportional sampling method. Data (BAC, sex, age, and manner of death) was recorded in a single structured protocol. Data was evaluated statistically (Kolmogorov-Smirnov two-sample test, Wilcoxon two-sample test, risk ratio). Among older people, there has been a statistically significant correlation of natural death with sex (men died earlier)...
Until recently, routine toxicological analysis of some hallucinogens in biological material posed... more Until recently, routine toxicological analysis of some hallucinogens in biological material posed problems which were only resolved after the introduction of modern analytic systems into toxicological laboratories. The most frequent hallucinogens in clinical and forensic toxicology can be grouped as: cannabinoids, tropane alkaloids, N,N-dimethyltryptamine derivatives and synthetic or semisynthetic hallucinogens. There are several methods currently used for their analysis. Immunoassay analysis of abused hallucinogens is limited to the cannabinoids. Thin layer chromatography (TLC) is able to detect higher concentrations of 1-nor-delta- 9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH), tropane alkaloids (atropine and scopolamine) and ketamine (synthetic hallucinogen) in urine but for lower concentrations and for some other substances it lacks sensitivity. A reliable solution to the demand for specific and sensitive analysis of hallucinogens in biological material is gas chromatograp...
Ibotenic acid, muscimol and muscarine were recognized as responsible for psychotropic effects of ... more Ibotenic acid, muscimol and muscarine were recognized as responsible for psychotropic effects of A. muscaria and A. pantherina. Demand for their specific and sensitive identification and quantitation in biological material lead to effort to develop reliable analytical method, but satisfactory solution is still lacking. Presented article describes liquid chromatography-mass spectrometry method suitable for isolation and identification of principal toxins of A. muscaria and A. pantherina in urine. Dedicated liquid chromatography-mass spectrometry method is reported. Technique consists of an extraction of analytes on Strata X-CW and Discovery SCX SPE cartridges and separation is achieved using a Gemini C18 column (150 mm x 2.0 mm, 5 micron) and 8 mM heptafluorobutyric acid as mobile phase. Detection at m/z 159 for ibotenic acid, m/z 115 for muscimol and m/z 174 for muscarine was used. Retention times and LODs are 2.6 min and 50 ng.ml-1 for ibotenic acid, 4.6 min and 40 ng.ml-1 for musc...
The electrochemical behavior of the herbicide prometryne was studied in aqueous solutions by DC p... more The electrochemical behavior of the herbicide prometryne was studied in aqueous solutions by DC polarography, differential pulse and cyclic voltammetry and by constant potential coulometry. Only the protonated form of prometryne can be reduced at pH < 6.5. The electrode process includes two irreversible steps. The two-electron reduction of the C–S bond leads to its splitting and a release of methylthiol molecule. The triazine ring of the reduction product is immediately reduced under the uptake of two electrons. Both the intermediate and final products of constant potential electrolysis were identified using chromatographic techniques and mass spectrometric analysis. The reduction mechanism of other 2-methylthio-4,6-dialkylamino-s-triazines is identical.
Direct oral anticoagulants are an alternative to anticoagulants based on vitamin K antagonists. M... more Direct oral anticoagulants are an alternative to anticoagulants based on vitamin K antagonists. Monitoring of direct oral anticoagulant concentration levels is necessary in specific cases only (e.g., emergency conditions, determination of the cause of bleeding, adverse effects, risk of drug-direct oral anticoagulants interaction); therefore, a sensitive and specific method is needed. Methanol protein precipitation method followed by liquid chromatography with high-resolution mass spectrometry was developed for simultaneous separation and determination of apixaban, betrixaban, edoxaban, dabigatran, rivaroxaban, and ximelagatran. The proposed method was fully validated in terms of linearity, the limits of detection and quantification, intra- and inter-day trueness and precision, recovery, matrix effect, process efficiency, and stability. The method shows a strong correlation (Pearson's correlation coefficients higher than 0.92) with coagulation assays of apixaban, dabigatran, and rivaroxaban (dTT for gatrans and antiXa activity for xabans). In addition, the developed method was applied for the identification and determination of apixaban and dabigatran in post-mortem serum samples. The developed method is a good alternative to coagulation tests which, however, may show various interferences.
Targeting the aryl hydrocarbon receptor (AhR) is an emerging therapeutic strategy for multiple di... more Targeting the aryl hydrocarbon receptor (AhR) is an emerging therapeutic strategy for multiple diseases (e.g., inflammatory bowel disease). Thermosporothrix hazakensis microbial metabolite 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) is a putative AhR endogenous ligand. To improve the chemical stability, we synthesized a series of ITE chemical mimics. Using a series of in vitro assays, we identified 2-(1H-indole-3-carbonyl)-N-methyl thiazole-4-carboxamide (ITE-CONHCH3) as a highly potent (EC50 = 1.6 nM) AhR agonist with high affinity (Ki = 88 nM). ITE-CONHCH3 triggered AhR nuclear translocation and dimerization of AhR-ARNT, enhanced AhR binding in the CYP1A1 promoter, and induced AhR-regulated genes in an AhR-dependent manner. The metabolic stability of ITE-CONHCH3 in a cell culture was 10 times higher than that of ITE. Finally, we observed protective effects of ITE-CONHCH3 in mice with DSS-induced colitis. Overall, we demonstrate and validate a concept of microbial metabolite mimicry in the therapeutic targeting of AhR.
Publikace Soudni lekařstvi I tvoři prvni dil uceleneho souhrnu nejmodernějsich informaci v oblast... more Publikace Soudni lekařstvi I tvoři prvni dil uceleneho souhrnu nejmodernějsich informaci v oblasti medicinských forenznich věd. Organicky navazuje na ucebnici doc. Vorla, vydanou ovsem před vice než 20 lety (1993), ktera je stale chapana jako volne pokracovani ucebnice prof. Tesaře (prvni vydani 1975). Text, na němž se podileli odbornici ze vsech soudnělekařských zařizeni v CR a castecně i z.e Slovenska, je sice urcen v prvni řadě soudnim lekařům, ale užitecne informace v něm najdou i dalsi obory, a to nejen medicinske a pravni. Prvni dil obsahuje 18 kapitol pocinaje historii soudniho lekařstvi jako jednoho z nejstarsich lekařských oborů v Ceske republice. K. nutnemu vzdělani soucasných lekařů neodmyslitelně patři i gramotnost pravni. To je obsahem 2. a 5. kapitoly. V dalsich kapitolach je podrobně rozebrana obecna problematika smrti, vcetně posmrtných změn, urcovani doby smrti a vitality poraněni. Svoji multioborovost prokazuje soudni lekařstvi zejmena v kapitole 6 Identifikace oso...
Objective: There is limited information about long term variability of patient compliance to anti... more Objective: There is limited information about long term variability of patient compliance to antihypertensive medication. The aim of our study was to evaluate changes in long term compliance in patients with resistant arterial hypertension taking beta-blockers. Design and method: Population and Methods: The serum levels of the prescribed beta-blockers were repeatedly evaluated in patients treated in our department for resistant arterial hypertension. The minimum time difference between single measurements in one patient was 3 month. If the serum level of the prescribed beta-blocker was within therapeutic range, patient was regarded as compliant at the particular visit. If the serum level was subtherapeutic or the beta-blocker was not present in serum at all, patient was regarded as noncompliant. Results: In 39 patients (56% men) we performed total of 146 measurements of serum beta-blocker level with average of 3.74 (±1.56) measurements per each patient. Mean baseline blood pressure ...
The phenolic composition of the aerial parts and corms of C. bornmuelleri, C. kotschyi, C. macrop... more The phenolic composition of the aerial parts and corms of C. bornmuelleri, C. kotschyi, C. macrophyllum and C. speciosum were analysed by capillary GC or GC-MS and twenty-three phenolics were identified. The phenolic fractions were tested for their cytoprotective effect on tBH-induced injury on isolated rat hepatocytes. The results indicate that phenotic fractions from leaves and flowers and the main constituent luteolin reduced the tBH-induced LPX and leakage of LDH. In contrast, phenolic fractions from seeds, not containing luteolin, had no significant effect on LDH though a decrease in LPx was observed.
The article presents the possibilities of identification of selected antidepressants of new gener... more The article presents the possibilities of identification of selected antidepressants of new generations in biological materials. Identification of the drugs by TLC and GC-MS after ether extraction from biological materials (urine, stomach content) was tested. The detection is sensitive and reliable for most of the drugs. For quantitative GC-MS analysis, the drugs were isolated from blood or serum by solid phase extraction (SPE). The recovery of most drugs is over 70 %. Limits of detection (LOD, 3 S/N) as well as limits of quantification (LOQ, 10 S/N) have been determined. The LOD are 0.5−2 ng l−1 for citalopram, maprotiline, mianserine, mirtazapine, moclobemide, sertraline and venlafaxine, 15 ng l−1 for fluoxetine and milnacipran and 50 ng l−1 for fluvoxamine, paroxetine and trazodone. LOQ are 2−5 ng l−1 for citalopram, maprotiline, mianserine, mirtazapine, moclobemide, sertraline and venlafaxine, 50 ng l−1 for fluoxetine and milnacipran and 100 ng l−1 for fluvoxamine, paroxetine an...
Alcohol abuse is related to a wide variety of negative health outcomes including mortality in old... more Alcohol abuse is related to a wide variety of negative health outcomes including mortality in older people. Alcohol abuse in older people is characterised by certain specific features uncommon in general adult population. The main objective of this study was to analyse the autopsy protocols of deceased older people in relation to blood alcohol concentration (BAC), sex, age, and manner of death. As a positive BAC, >0.20 g/kg was accepted. The sample consists of 1,012 deceased older people (i.e. aged 65 years and over) selected out of 2,377 autopsied subjects in the period from 2003–2013. Subjects included into the sample were chosen via the proportional sampling method. Data (BAC, sex, age, and manner of death) was recorded in a single structured protocol. Data was evaluated statistically (Kolmogorov-Smirnov two-sample test, Wilcoxon two-sample test, risk ratio). Among older people, there has been a statistically significant correlation of natural death with sex (men died earlier)...
Until recently, routine toxicological analysis of some hallucinogens in biological material posed... more Until recently, routine toxicological analysis of some hallucinogens in biological material posed problems which were only resolved after the introduction of modern analytic systems into toxicological laboratories. The most frequent hallucinogens in clinical and forensic toxicology can be grouped as: cannabinoids, tropane alkaloids, N,N-dimethyltryptamine derivatives and synthetic or semisynthetic hallucinogens. There are several methods currently used for their analysis. Immunoassay analysis of abused hallucinogens is limited to the cannabinoids. Thin layer chromatography (TLC) is able to detect higher concentrations of 1-nor-delta- 9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH), tropane alkaloids (atropine and scopolamine) and ketamine (synthetic hallucinogen) in urine but for lower concentrations and for some other substances it lacks sensitivity. A reliable solution to the demand for specific and sensitive analysis of hallucinogens in biological material is gas chromatograp...
Ibotenic acid, muscimol and muscarine were recognized as responsible for psychotropic effects of ... more Ibotenic acid, muscimol and muscarine were recognized as responsible for psychotropic effects of A. muscaria and A. pantherina. Demand for their specific and sensitive identification and quantitation in biological material lead to effort to develop reliable analytical method, but satisfactory solution is still lacking. Presented article describes liquid chromatography-mass spectrometry method suitable for isolation and identification of principal toxins of A. muscaria and A. pantherina in urine. Dedicated liquid chromatography-mass spectrometry method is reported. Technique consists of an extraction of analytes on Strata X-CW and Discovery SCX SPE cartridges and separation is achieved using a Gemini C18 column (150 mm x 2.0 mm, 5 micron) and 8 mM heptafluorobutyric acid as mobile phase. Detection at m/z 159 for ibotenic acid, m/z 115 for muscimol and m/z 174 for muscarine was used. Retention times and LODs are 2.6 min and 50 ng.ml-1 for ibotenic acid, 4.6 min and 40 ng.ml-1 for musc...
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