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Riedl M, Camargo S, Anteneodo C, Kurths J, Wessel N. Quantification of heart beat nonstationarities by nonparametric segmentation. BIOMED ENG-BIOMED TE 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-G/bmt-2013-4170/bmt-2013-4170.xml. [DOI: 10.1515/bmt-2013-4170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Wessel N, Marwan N, Krämer JF, Kurths J. TOCSY - Toolboxes for modelling of dynamical systems and time series. BIOMED ENG-BIOMED TE 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-G/bmt-2013-4180/bmt-2013-4180.xml. [DOI: 10.1515/bmt-2013-4180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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53
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Penzel T, Riedl M, Gapelyuk A, Suhrbier A, Bretthauer G, Malberg H, Schöbel C, Fietze I, Heitmann J, Kurths J, Wessel N. Effect of CPAP therapy on daytime cardiovascular regulations in patients with obstructive sleep apnea. Comput Biol Med 2012; 42:328-34. [DOI: 10.1016/j.compbiomed.2011.09.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 08/10/2011] [Accepted: 09/07/2011] [Indexed: 01/01/2023]
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54
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Parlitz U, Berg S, Luther S, Schirdewan A, Kurths J, Wessel N. Classifying cardiac biosignals using ordinal pattern statistics and symbolic dynamics. Comput Biol Med 2012; 42:319-27. [DOI: 10.1016/j.compbiomed.2011.03.017] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 03/02/2011] [Accepted: 03/28/2011] [Indexed: 11/30/2022]
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Wessel N, Kurths J, Malberg H, Penzel T. Biosignal 2010: Advanced technologies in intensive care and sleep medicine. Physiol Meas 2012; 32:2 p preceding 1715. [PMID: 22141150 DOI: 10.1088/0967-3334/32/11/e01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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56
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Wessel N, van Leeuwen P. Computing complexity in cardiovascular oscillations: selected papers from the 6th Conference of the ESGCO. Comput Biol Med 2012; 42:265-6. [PMID: 22325358 DOI: 10.1016/j.compbiomed.2012.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 01/19/2012] [Indexed: 01/18/2023]
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57
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Wessel N, Ménard D, Pichavant-Rafini K, Ollivier H, Le Goff J, Burgeot T, Akcha F. Genotoxic and enzymatic effects of fluoranthene in microsomes and freshly isolated hepatocytes from sole (Solea solea). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 108:33-41. [PMID: 22036012 DOI: 10.1016/j.aquatox.2011.09.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 09/23/2011] [Accepted: 09/29/2011] [Indexed: 05/22/2023]
Abstract
The fluoranthene (Fluo) is one of the most abundant polycyclic aromatic hydrocarbons (PAHs) in human food and in marine compartments. However, the existing data on its genotoxicity is poor and controversial. The aim of this study was to assess in vitro the potential genotoxicity of Fluo in sole and its possible effect on CYP450 modulation. Freshly isolated hepatocytes were exposed for 24 h to a range of Fluo concentrations from 0.5 to 50 μM in both culture flasks and microplate wells. The ethoxyresorufin-O-deethylase (EROD) activity was measured as an indicator of the activity of the cytochrome P450 1A1 (CYP1A1). The genotoxic effects were evaluated by measuring both DNA strand breaks and DNA adducts by the alkaline comet assay and the postlabeling technique respectively. Calf thymus DNA was also exposed to Fluo in the presence of sole liver microsomes in order to check for Fluo DNA adduct formation. In sole hepatocytes, Fluo was shown to induce a decrease in the EROD activity in a concentration-dependent manner. A significant genotoxic effect was observed in terms of DNA strand breakage from an exposure concentration of 5 μM: despite a concentration-dependent effect was observed, it did not follow a linear dose-response. The response was similar whatever the way of exposure in flasks or in wells. One reproducible adduct was detected in the hepatocytes exposed to the highest concentrations of Fluo. The formation of Fluo adducts was confirmed by the detection of one reproducible adduct following in vitro exposure of calf thymus DNA to 100 and 200 μM of Fluo in the presence of sole microsomes. These results demonstrate the potential of sole hepatocytes to metabolize Fluo in 24 h into reactive species, able to induce genotoxicity by DNA strand breakage and DNA adduct formation. Moreover, a miniaturized cell exposure system was validated for further experiments using fewer amounts of hepatocytes and contaminants, and allowing exposure to PAH metabolites.
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Riedl M, Penzel T, Wessel N. Coupling analysis in sleep medicine by means of symbolic coupling traces. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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59
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Huhle R, Burghardt M, Zaunseder S, Wessel N, Koch T, Malberg H, Heller AR. Effects of awareness and nociception on heart rate variability during general anaesthesia. Physiol Meas 2012; 33:207-17. [PMID: 22260880 DOI: 10.1088/0967-3334/33/2/207] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
During anaesthesia awareness and nociception are serious complications that may further lead to haemodynamic instability. Specific monitoring of depth of hypnosis and depth of analgesia based on heart rate variability (HRV) analysis is eligible to improve patient safety and reduce efforts in post-operative care. Consequently, in this analysis we assess the applicability of HRV parameters during surgical interventions with standardized intravenous propofol-remifentanil-anaesthesia. Peri-operative electrocardiograms were recorded from cardiovascular stable patients (ASA Score I/II, N = 32, age: 36.4 ± 11.23 a, BMI: 25.2 ± 3.16) scheduled for trauma and dentofacial surgery. HRV time- and frequency-domain parameters, measures of complexity and nonlinear dynamics were compared by analysing longitudinally distributed 300 s intervals preceding/following induction of anaesthesia (BL-I1), intubation (I1-I2) and extubation (E1-E2). Mean value (meanNN) and standard deviation (sdNN) of the heart rate are influenced in BL-I1 (p < 0.001), I1-I2 (p < 0.05) and E1-E2 (p < 0.001). The number of forbidden words of symbolic dynamics changes significantly for BL-I1 (p < 0.001) and not for I1-I2 and E1-E2 (p > 0.05). Probability of low-variability POLVAR10 is significantly altered in all comparisons (BL-I1: Δ = 0.032, p < 0.01, I1-I2: Δ = 0.12, p < 0.05, E1-E2: Δ = 0.169, p < 0.01) but especially during nociception. While standard time-domain parameters lacked selectivity, parameters of symbolic dynamics appear to be specifically influenced by changes in depth of hypnosis and nociception, respectively. However, the lack of steady-state ventilation/breathing in this study needs to be considered in future research. To be used for clinical anaesthesia monitoring our results have to be prospectively validated in clinical studies.
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Wang Y, Moreira MDCV, Khan A, Heringer-Walther S, Schultheiss HP, Wessel N, Siems WE, Walther T. Prognostic Significance of Circulating Levels of Hepatocyte Growth Factor in Patients with Chagas Disease and Idiopathic Dilated Cardiomyopathy. Cardiology 2012; 121:240-6. [DOI: 10.1159/000337080] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 01/11/2012] [Indexed: 11/19/2022]
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61
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Retzlaff B, Wessel N, Riedl M, Gapelyuk A, Malberg H, Bauernschmitt N, Kurths J, Bretthauer G, Bauernschmitt R. Preserved autonomic regulation in patients undergoing transcatheter aortic valve implantation (TAVI) – a prospective, comparative study. ACTA ACUST UNITED AC 2011; 56:185-93. [DOI: 10.1515/bmt.2011.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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62
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Penzel T, Suhrbier A, Bretthauer G, Riedl M, Wessel N, Kurths J, Malberg H, Fietze I. Cardiovascular and respiratory regulation during sleep in patients with sleep apnea with and without hypertension. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2011; 2011:1475-1478. [PMID: 22254598 DOI: 10.1109/iembs.2011.6090360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Sleep is a physiological process with an internal program of a number of well defined sleep stages and intermediate wakefulness periods. The sleep stages do modulate the autonomous nervous system and thereby the sleep stages are accompanied by different regulation regimes for the cardiovascular and respiratory system. The differences in regulation can be distinguished by new analysis techniques on the recorded signals. In addition to normal sleep regulation some sleep disorders affect the cardiovascular and respiratory regulation. The most prevalent disorder linked to sleep and changes in the autonomous system is obstructive sleep apnea. In patients with obstructive sleep apnea marked short term changes in cardiovascular and respiratory regulation are observed during sleep. These abnormalities in regulation are further differentiated between the sleep stages. For long term changes obstructive sleep apnea is recognized as a major risk factor for arterial hypertension. Treatment of obstructive sleep apnea lowers blood pressure during the night and over time also lowers blood pressure during daytime. In this study we investigated 18 patients with sleep apnea and normal blood pressure, 10 patients with sleep apnea and arterial hypertension and 10 normal subjects as controls. Both patient groups were tested with cardiorespiratory polysomnography before and under CPAP therapy. The effects on cardiovascular and respiratory regulation during sleep and daytime are investigated in the three groups.
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63
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Wessel N, Suhrbier A, Riedl M, Marwan N, Malberg H, Bretthauer G, Penzel T, Kurths J. Symbolic coupling traces for causality analysis of cardiovascular control. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2011; 2011:5935-5938. [PMID: 22255691 DOI: 10.1109/iembs.2011.6091468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Directional coupling analysis of time series is an important subject of current research. In this paper, a method based on symbolic dynamics for the detection of time-delayed coupling in biosignals is presented. The symbolic coupling traces, defined as the symmetric and diametric traces of the bivariate word distribution, allow for a more reliable quantification of coupling and are compared with established methods like mutual information and cross recurrence analysis. The symbolic coupling traces method is applied to appropriate model systems and cardiological data which demonstrate its advantages especially for nonstationary and noisy data. Moreover, the method of symbolic coupling traces is used to analyze and quantify time-delayed coupling of cardiovascular measurements during different sleep stages. Significant different regulatory mechanisms are detected not only between the deep sleep and the other sleep stages but also between healthy subjects and patients. The proposed method may help to indicate pathological changes in cardiovascular regulation and also effects of continuous positive airway pressure therapy on the cardiovascular system.
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64
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Gapelyuk A, Riedl M, Suhrbier A, Kraemer JF, Bretthauer G, Malberg H, Kurths J, Penzel T, Wessel N. Cardiovascular regulation in different sleep stages in the obstructive sleep apnea syndrome. ACTA ACUST UNITED AC 2011; 56:207-13. [DOI: 10.1515/bmt.2011.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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65
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Suhrbier A, Riedl M, Malberg H, Penzel T, Bretthauer G, Kurths J, Wessel N. Cardiovascular regulation during sleep quantified by symbolic coupling traces. CHAOS (WOODBURY, N.Y.) 2010; 20:045124. [PMID: 21198136 DOI: 10.1063/1.3518688] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Sleep is a complex regulated process with short periods of wakefulness and different sleep stages. These sleep stages modulate autonomous functions such as blood pressure and heart rate. The method of symbolic coupling traces (SCT) is used to analyze and quantify time-delayed coupling of these measurements during different sleep stages. The symbolic coupling traces, defined as the symmetric and diametric traces of the bivariate word distribution matrix, allow the quantification of time-delayed coupling. In this paper, the method is applied to heart rate and systolic blood pressure time series during different sleep stages for healthy controls as well as for normotensive and hypertensive patients with sleep apneas. Using the SCT, significant different cardiovascular mechanisms not only between the deep sleep and the other sleep stages but also between healthy subjects and patients can be revealed. The SCT method is applied to model systems, compared with established methods, such as cross correlation, mutual information, and cross recurrence analysis and demonstrates its advantages especially for nonstationary physiological data. As a result, SCT proves to be more specific in detecting delays of directional interactions than standard coupling analysis methods and yields additional information which cannot be measured by standard parameters of heart rate and blood pressure variability. The proposed method may help to indicate the pathological changes in cardiovascular regulation and also the effects of continuous positive airway pressure therapy on the cardiovascular system.
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66
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Penzel T, Wessel N, Riedl M, Kantelhardt JW, Glos M, Fietze I. Cardiovascular and respiratory dynamics in patients with sleep apnea. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2010:276-9. [PMID: 21096754 DOI: 10.1109/iembs.2010.5627434] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Sleep is an active and regulated process with restorative functions for physical and mental conditions. Based on recordings of brain waves and the analysis of characteristic patterns and waveforms it is possible to distinguish wakefulness and five sleep stages. Sleep and the sleep stages modulate autonomous nervous system functions such as body temperature, respiration, blood pressure, and heart rate. Methods of statistical physics are used to analyze heart rate and respiration to detect changes of the autonomous nervous system during sleep. Detrended fluctuation analysis and synchronization analysis and their applications to heart rate and respiration during sleep in healthy subjects and patients with sleep disorders are presented. The observed changes can be used to distinguish sleep stages in healthy subjects as well as to differentiate normal and disturbed sleep on the basis of heart rate and respiration recordings without direct recording of brain waves. Of special interest are the cardiovascular consequences of disturbed sleep because they present a risk factor for cardiovascular disorders such as arterial hypertension, cardiac ischemia, sudden cardiac death, and stroke.
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67
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Gapelyuk A, Schirdewan A, Fischer R, Wessel N. Cardiac magnetic field mapping quantified by Kullback-Leibler entropy detects patients with coronary artery disease. Physiol Meas 2010; 31:1345-54. [PMID: 20720289 DOI: 10.1088/0967-3334/31/10/004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cardiac magnetic field mapping (CMFM) is a noninvasive method to determine cardiac electrical activity. We analysed the utility of CMFM for the detection of patients with coronary artery disease (CAD) without subjecting them to stress. We studied 59 healthy control subjects and 101 patients with CAD without previous myocardial infarction (MI). The heart's magnetic field was recorded over the anterior chest wall using a multichannel magnetic measurement system with axial second-order gradiometers. The evaluation of CMFM was based on comparison of the 'ideal' group mean maps of young healthy subjects and maps of examined individuals. Three measures of similarity were considered: Kullback-Leibler (KL) entropy, normalized residual magnetic field strength and deviations in the magnetic field map orientation. The mean values of these parameters during the depolarization and repolarization were used for further classification with the help of logistic regression. The feature set based on the KL-entropy demonstrated the best classification results (sensitivity/specificity of 85/80%), followed by the residual feature (85/75%) and the magnetic field orientation feature (80/73%) sets. The forward stepwise technique was applied to select the best set of features from the combined feature set. Two parameters were selected, namely the KL-entropy for the repolarization period and the residual parameter for the depolarization period. The classification based on these parameters demonstrated a sensitivity of 88% and a specificity of 88% for the distinction of CAD patients from the control subjects. The area under the receiver operator curve was 94%. Hence, we suggest that CMFM evaluation based on KL-entropy is a promising technique to identify patients with CAD.
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68
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Riedl M, Suhrbier A, Stepan H, Kurths J, Wessel N. Short-term couplings of the cardiovascular system in pregnant women suffering from pre-eclampsia. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2010; 368:2237-2250. [PMID: 20368244 DOI: 10.1098/rsta.2010.0029] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Pre-eclampsia (PE), a serious pregnancy-specific disorder, causes significant neonatal and maternal morbidity and mortality. Recent studies showed that cardiovascular variability parameters as well as the baroreflex sensitivity remarkably improve its early diagnosis. For a better understanding of the dynamical changes caused by PE, in this study the coupling between respiration, systolic and diastolic blood pressure, and heart rate is investigated. Thirteen datasets of healthy pregnant women and 10 of subjects suffering from PE are included. Nonlinear additive autoregressive models with external input are used for a model-based coupling analysis following the idea of Granger causality. To overcome the problem of misdetections of standard methods in systems with a dominant driver, a heuristic ensemble approach is used here. A coupling is assumed to be real when existent in more than 80 per cent of the ensemble members, and otherwise denoted as artefacts. As the main result, we found that the coupling structure between heart rate, systolic blood pressure, diastolic blood pressure and respiration for healthy subjects and PE patients is the same and reliable. As a pathological mechanism, however, a significant increased respiratory influence on the diastolic blood pressure could be found for PE patients (p=0.003). Moreover, the nonlinear form of the respiratory influence on the heart rate is significantly different between the two groups (p=0.002). Interestingly, the influence of systolic blood pressure on the heart rate is not selected, which indicates that the baroreflex sensitivity estimation strongly demands the consideration of causal relationships between heart rate, blood pressure and respiration. Finally, our results point to a potential role of respiration for understanding the pathogenesis of PE.
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69
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Wessel N, Santos R, Menard D, Le Menach K, Buchet V, Lebayon N, Loizeau V, Burgeot T, Budzinski H, Akcha F. Relationship between PAH biotransformation as measured by biliary metabolites and EROD activity, and genotoxicity in juveniles of sole (Solea solea). MARINE ENVIRONMENTAL RESEARCH 2010; 69 Suppl:S71-S73. [PMID: 20417553 DOI: 10.1016/j.marenvres.2010.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 03/09/2010] [Accepted: 03/11/2010] [Indexed: 05/29/2023]
Abstract
Polycylic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in the marine environment. Their toxicity is mainly linked to the ability of marine species to biotransform them into reactive metabolites. PAHs are thus often detected at trace levels in animal tissues. For biomonitoring purposes, this findings have two main consequences, (i) the determination of the PAH tissue concentration is not suitable for the evaluation of individual exposure to PAHs (ii) it can explain sometimes the lack of correlations obtained with relevant markers of toxicity such as genotoxicity biomarkers. The aim of the present study was to better investigate the link between PAH exposure and genotoxicity in marine flatfish. During a laboratory experiment, juvenile soles were exposed for four weeks to a mixture of three PAHs, namely benzo[a]pyrene, fluoranthene and pyrene, followed by one week of depuration. Fish were exposed via the trophic route to a daily PAH concentration of 120 μg/g food. Fish were sampled at different time points. The bioavailability and the biotransformation of PAHs were assessed by the measurement of biliary metabolites using a sensitive UPLC MS/MS method. The 7-ethoxyresorufine-O-deethylase was also measured in liver subcellular fractions as a biomarker of phase I biotransformation activities. Genotoxicity was assessed in parallel by the measurement of DNA strand breaks in fish erythrocytes by the alkaline comet assay. During this study, the high amount of PAH metabolites produced in sole demonstrated the bioavailability of PAHs and their biotransformation by fish enzymes. A positive correlation was observed between the level of hydroxylated PAH metabolites and genotoxicity as measured by the alkaline comet assay.
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70
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Wang Y, Moreira MDCV, Heringer-Walther S, Ebermann L, Schultheiss HP, Wessel N, Siems WE, Walther T. Plasma ACE2 Activity is an Independent Prognostic Marker in Chagas' Disease and Equally Potent as BNP. J Card Fail 2010; 16:157-63. [DOI: 10.1016/j.cardfail.2009.09.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 09/15/2009] [Accepted: 09/23/2009] [Indexed: 11/25/2022]
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71
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Wang Y, Moreira MDCV, Heringer-Walther S, Schultheiss HP, Siems WE, Wessel N, Walther T. Amino-terminal Fragment of C-type Natriuretic Peptide Precursor and C-type Natriuretic Peptide Do Not Correlate in Patients With Chagas Disease: Role For Neutral Endopeptidase. J Cardiovasc Pharmacol 2010; 55:62-6. [DOI: 10.1097/fjc.0b013e3181c37dc2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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72
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Voss A, Wessel N, Hasart A, Hähnel H, Prasse G, Schirdewan A, Osterziel KJ. Analyse von Kurzzeit-Blutdruck- und Herzfrequenzvariabilität. BIOMED ENG-BIOMED TE 2009. [DOI: 10.1515/bmte.1998.43.s1.106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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73
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Moreira MDCV, Wang Y, Heringer-Walther S, Wessel N, Walther T. Prognostic value of natriuretic peptides in Chagas' disease: a head-to-head comparison of the 3 natriuretic peptides. ACTA ACUST UNITED AC 2009; 15:75-81. [PMID: 19379453 DOI: 10.1111/j.1751-7133.2009.00051.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
To determine the diagnostic and prognostic value of natriuretic peptides in patients with Chagas' disease (CD), the authors first measured atrial (ANP), B-type (BNP), and C-type natriuretic peptide (CNP) and compared their diagnostic and prognostic capacity with that in other dilated cardiomyopathies (DCM). The CD and DCM patients were subdivided according to their New York Heart Association (NYHA) classification. Circulating ANP and more pronounced BNP, but not CNP, were increased in CD and DCM patients in relation to NYHA class. Importantly, ANP and BNP were already significantly elevated in CD patients without systolic ventricular dysfunction. All 3 natriuretic peptides were correlated with echocardiographic parameters in CD patients. While ANP and BNP have high predictive value for mortality and necessity for heart transplant in CD, CNP can not predict them. Thus, ANP and BNP rather than CNP could be used as valuable molecular markers to identify asymptomatic CD patients for early therapy and predict clinical outcomes.
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Voss A, Kurths J, Kleiner H, Witt A, Dietz R, Saparin P, Fiehring H, Wessel N. Einsatz von Verfahren der nichtlinearen Dynamik zur Erkennung von Risikopatienten für den plötzlichen Herztod. BIOMED ENG-BIOMED TE 2009. [DOI: 10.1515/bmte.1994.39.s1.278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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75
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Wessel N, Riedl M, Kurths J. Is the normal heart rate "chaotic" due to respiration? CHAOS (WOODBURY, N.Y.) 2009; 19:028508. [PMID: 19566283 DOI: 10.1063/1.3133128] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The incidence of cardiovascular diseases increases with the growth of the human population and an aging society, leading to very high expenses in the public health system. Therefore, it is challenging to develop sophisticated methods in order to improve medical diagnostics. The question whether the normal heart rate is chaotic or not is an attempt to elucidate the underlying mechanisms of cardiovascular dynamics and therefore a highly controversial topical challenge. In this contribution we demonstrate that linear and nonlinear parameters allow us to separate completely the data sets of the three groups provided for this controversial topic in nonlinear dynamics. The question whether these time series are chaotic or not cannot be answered satisfactorily without investigating the underlying mechanisms leading to them. We give an example of the dominant influence of respiration on heart beat dynamics, which shows that observed fluctuations can be mostly explained by respiratory modulations of heart rate and blood pressure (coefficient of determination: 96%). Therefore, we recommend reformulating the following initial question: "Is the normal heart rate chaotic?" We rather ask the following: "Is the normal heart rate 'chaotic' due to respiration?"
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