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Bojić, Tijana

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orcid::0000-0003-1149-5697
  • Bojić, Tijana (21)
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Author's Bibliography

Slow 0.1 Hz Breathing and Body Posture Induced Perturbations of RRI and Respiratory Signal Complexity and Cardiorespiratory Coupling

Matić, Zoran; Platiša, Mirjana M.; Kalauzi, Aleksandar; Bojić, Tijana

(2020)

TY  - JOUR
AU  - Matić, Zoran
AU  - Platiša, Mirjana M.
AU  - Kalauzi, Aleksandar
AU  - Bojić, Tijana
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8848
AB  - Objective: We explored the physiological background of the non-linear operating mode of cardiorespiratory oscillators as the fundamental question of cardiorespiratory homeodynamics and as a prerequisite for the understanding of neurocardiovascular diseases. We investigated 20 healthy human subjects for changes using electrocardiac RR interval (RRI) and respiratory signal (Resp) Detrended Fluctuation Analysis (DFA, α1RRI, α2RRI, α1Resp, α2Resp), Multiple Scaling Entropy (MSERRI1−4, MSERRI5−10, MSEResp1−4, MSEResp5−10), spectral coherence (CohRRI−Resp), cross DFA (ρ1 and ρ2) and cross MSE (XMSE1−4 and XMSE5−10) indices in four physiological conditions: supine with spontaneous breathing, standing with spontaneous breathing, supine with 0.1 Hz breathing and standing with 0.1 Hz breathing. Main results: Standing is primarily characterized by the change of RRI parameters, insensitivity to change with respiratory parameters, decrease of CohRRI−Resp and insensitivity to change of in ρ1, ρ2, XMSE1−4, and XMSE5−10. Slow breathing in supine position was characterized by the change of the linear and non-linear parameters of both signals, reflecting the dominant vagal RRI modulation and the impact of slow 0.1 Hz breathing on Resp parameters. CohRRI−Resp did not change with respect to supine position, while ρ1 increased. Slow breathing in standing reflected the qualitatively specific state of autonomic regulation with striking impact on both cardiac and respiratory parameters, with specific patterns of cardiorespiratory coupling. Significance: Our results show that cardiac and respiratory short term and long term complexity parameters have different, state dependent patterns. Sympathovagal non-linear interactions are dependent on the pattern of their activation, having different scaling properties when individually activated with respect to the state of their joint activation. All investigated states induced a change of α1 vs. α2 relationship, which can be accurately expressed by the proposed measure—inter-fractal angle θ. Short scale (α1 vs. MSE1−4) and long scale (α2 vs. MSE5−10) complexity measures had reciprocal interrelation in standing with 0.1 Hz breathing, with specific cardiorespiratory coupling pattern (ρ1 vs. XMSE1−4). These results support the hypothesis of hierarchical organization of cardiorespiratory complexity mechanisms and their recruitment in ascendant manner with respect to the increase of behavioral challenge complexity. Specific and comprehensive cardiorespiratory regulation in standing with 0.1 Hz breathing suggests this state as the potentially most beneficial maneuver for cardiorespiratory conditioning. © Copyright © 2020 Matić, Platiša, Kalauzi and Bojić.
T2  - Frontiers in Physiology
T1  - Slow 0.1 Hz Breathing and Body Posture Induced Perturbations of RRI and Respiratory Signal Complexity and Cardiorespiratory Coupling
VL  - 11
SP  - 24
DO  - 10.3389/fphys.2020.00024
ER  - 
@article{
author = "Matić, Zoran and Platiša, Mirjana M. and Kalauzi, Aleksandar and Bojić, Tijana",
year = "2020",
url = "https://vinar.vin.bg.ac.rs/handle/123456789/8848",
abstract = "Objective: We explored the physiological background of the non-linear operating mode of cardiorespiratory oscillators as the fundamental question of cardiorespiratory homeodynamics and as a prerequisite for the understanding of neurocardiovascular diseases. We investigated 20 healthy human subjects for changes using electrocardiac RR interval (RRI) and respiratory signal (Resp) Detrended Fluctuation Analysis (DFA, α1RRI, α2RRI, α1Resp, α2Resp), Multiple Scaling Entropy (MSERRI1−4, MSERRI5−10, MSEResp1−4, MSEResp5−10), spectral coherence (CohRRI−Resp), cross DFA (ρ1 and ρ2) and cross MSE (XMSE1−4 and XMSE5−10) indices in four physiological conditions: supine with spontaneous breathing, standing with spontaneous breathing, supine with 0.1 Hz breathing and standing with 0.1 Hz breathing. Main results: Standing is primarily characterized by the change of RRI parameters, insensitivity to change with respiratory parameters, decrease of CohRRI−Resp and insensitivity to change of in ρ1, ρ2, XMSE1−4, and XMSE5−10. Slow breathing in supine position was characterized by the change of the linear and non-linear parameters of both signals, reflecting the dominant vagal RRI modulation and the impact of slow 0.1 Hz breathing on Resp parameters. CohRRI−Resp did not change with respect to supine position, while ρ1 increased. Slow breathing in standing reflected the qualitatively specific state of autonomic regulation with striking impact on both cardiac and respiratory parameters, with specific patterns of cardiorespiratory coupling. Significance: Our results show that cardiac and respiratory short term and long term complexity parameters have different, state dependent patterns. Sympathovagal non-linear interactions are dependent on the pattern of their activation, having different scaling properties when individually activated with respect to the state of their joint activation. All investigated states induced a change of α1 vs. α2 relationship, which can be accurately expressed by the proposed measure—inter-fractal angle θ. Short scale (α1 vs. MSE1−4) and long scale (α2 vs. MSE5−10) complexity measures had reciprocal interrelation in standing with 0.1 Hz breathing, with specific cardiorespiratory coupling pattern (ρ1 vs. XMSE1−4). These results support the hypothesis of hierarchical organization of cardiorespiratory complexity mechanisms and their recruitment in ascendant manner with respect to the increase of behavioral challenge complexity. Specific and comprehensive cardiorespiratory regulation in standing with 0.1 Hz breathing suggests this state as the potentially most beneficial maneuver for cardiorespiratory conditioning. © Copyright © 2020 Matić, Platiša, Kalauzi and Bojić.",
journal = "Frontiers in Physiology",
title = "Slow 0.1 Hz Breathing and Body Posture Induced Perturbations of RRI and Respiratory Signal Complexity and Cardiorespiratory Coupling",
volume = "11",
pages = "24",
doi = "10.3389/fphys.2020.00024"
}
2

Generalized Poincaré plots analysis of heart period dynamics in different physiological conditions: Trained vs. untrained men

Platiša, Mirjana M.; Bojić, Tijana; Mazić, Sanja D.; Kalauzi, Aleksandar

(2019)

TY  - JOUR
AU  - Platiša, Mirjana M.
AU  - Bojić, Tijana
AU  - Mazić, Sanja D.
AU  - Kalauzi, Aleksandar
PY  - 2019
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/8413
AB  - Background Recently we proposed a new method called generalized Poincare´ plot (gPp) analysis which gave a new insight into the pattern of neurocaridac control. In this study we examined potential of gPp method to reveal changes in cardiac neural control in young athletes during three conditions: supine rest, running and relaxation, with respect to untrained subjects. Methods This method is based on the quantification of Pearson's correlation coefficients r(j, k), between symmetrical (j = k) and asymmetrical summed j previous and k following RR intervals up to the 100th order (j,k.100). Results Differences between groups were obtained at all levels of this analysis. The main result is the significant difference of NAI, normalized index of asymmetry, between groups in running, which was originated in different positions of local maxima of r(j, k). Compared with untrained subjects, these findings indicate modified neural control and altered intrinsic heart rate behavior in athletes which are related to some kind of memory mechanism between RR intervals. Conclusion Obtained results provide great potential of gPp method analysis in the recognition of changes in neurocardiac control in healthy subjects. Further studies are needed for identification of altered cardiac regulatory mechanisms whose background may be useful in the evaluation of genesis of athletes neurocardiovascular pathology. © 2019 Platiša et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
T2  - PLOS ONE
T1  - Generalized Poincaré plots analysis of heart period dynamics in different physiological conditions: Trained vs. untrained men
VL  - 14
IS  - 7
SP  - e0219281
DO  - 10.1371/journal.pone.0219281
ER  - 
@article{
author = "Platiša, Mirjana M. and Bojić, Tijana and Mazić, Sanja D. and Kalauzi, Aleksandar",
year = "2019",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/8413",
abstract = "Background Recently we proposed a new method called generalized Poincare´ plot (gPp) analysis which gave a new insight into the pattern of neurocaridac control. In this study we examined potential of gPp method to reveal changes in cardiac neural control in young athletes during three conditions: supine rest, running and relaxation, with respect to untrained subjects. Methods This method is based on the quantification of Pearson's correlation coefficients r(j, k), between symmetrical (j = k) and asymmetrical summed j previous and k following RR intervals up to the 100th order (j,k.100). Results Differences between groups were obtained at all levels of this analysis. The main result is the significant difference of NAI, normalized index of asymmetry, between groups in running, which was originated in different positions of local maxima of r(j, k). Compared with untrained subjects, these findings indicate modified neural control and altered intrinsic heart rate behavior in athletes which are related to some kind of memory mechanism between RR intervals. Conclusion Obtained results provide great potential of gPp method analysis in the recognition of changes in neurocardiac control in healthy subjects. Further studies are needed for identification of altered cardiac regulatory mechanisms whose background may be useful in the evaluation of genesis of athletes neurocardiovascular pathology. © 2019 Platiša et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.",
journal = "PLOS ONE",
title = "Generalized Poincaré plots analysis of heart period dynamics in different physiological conditions: Trained vs. untrained men",
volume = "14",
number = "7",
pages = "e0219281",
doi = "10.1371/journal.pone.0219281"
}
4
2
4

Editorial: Neurocardiovascular Diseases: New Aspects of the Old Issues

Bojić, Tijana

(2019)

@article{
author = "Bojić, Tijana",
year = "2019",
url = "https://www.frontiersin.org/article/10.3389/fnins.2018.01032/full, http://vinar.vin.bg.ac.rs/handle/123456789/8179",
journal = "Frontiers in Neuroscience",
title = "Editorial: Neurocardiovascular Diseases: New Aspects of the Old Issues",
volume = "12",
number = "JAN",
doi = "10.3389/fnins.2018.01032"
}
1
1
1
1

Pathophysiology of Subjective Tinnitus: Triggers and Maintenance

Haider, Haula Faruk; Bojić, Tijana; Ribeiro, Sara F.; Paco, Joao; Hall, Deborah A.; Szczepek, Agnieszka J.

(2018)

TY  - JOUR
AU  - Haider, Haula Faruk
AU  - Bojić, Tijana
AU  - Ribeiro, Sara F.
AU  - Paco, Joao
AU  - Hall, Deborah A.
AU  - Szczepek, Agnieszka J.
PY  - 2018
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/7985
AB  - Tinnitus is the conscious perception of a sound without a corresponding external acoustic stimulus, usually described as a phantom perception. One of the major challenges for tinnitus research is to understand the pathophysiological mechanisms triggering and maintaining the symptoms, especially for subjective chronic tinnitus. Our objective was to synthesize the published literature in order to provide a comprehensive update on theoretical and experimental advances and to identify further research and clinical directions. We performed literature searches in three electronic databases, complemented by scanning reference lists from relevant reviews in our included records, citation searching of the included articles using Web of Science, and manual searching of the last 6 months of principal otology journals. One-hundred and thirty-two records were included in the review and the information related to peripheral and central mechanisms of tinnitus pathophysiology was collected in order to update on theories and models. A narrative synthesis examined the main themes arising from this information. Tinnitus pathophysiology is complex and multifactorial, involving the auditory and non-auditory systems. Recent theories assume the necessary involvement of extra-auditory brain regions for tinnitus to reach consciousness. Tinnitus engages multiple active dynamic and overlapping networks. We conclude that advancing knowledge concerning the origin and maintenance of specific tinnitus subtypes origin and maintenance mechanisms is of paramount importance for identifying adequate treatment.
T2  - Frontiers in Neuroscience
T1  - Pathophysiology of Subjective Tinnitus: Triggers and Maintenance
VL  - 12
SP  - 00866
DO  - 10.3389/fnins.2018.00866
ER  - 
@article{
author = "Haider, Haula Faruk and Bojić, Tijana and Ribeiro, Sara F. and Paco, Joao and Hall, Deborah A. and Szczepek, Agnieszka J.",
year = "2018",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/7985",
abstract = "Tinnitus is the conscious perception of a sound without a corresponding external acoustic stimulus, usually described as a phantom perception. One of the major challenges for tinnitus research is to understand the pathophysiological mechanisms triggering and maintaining the symptoms, especially for subjective chronic tinnitus. Our objective was to synthesize the published literature in order to provide a comprehensive update on theoretical and experimental advances and to identify further research and clinical directions. We performed literature searches in three electronic databases, complemented by scanning reference lists from relevant reviews in our included records, citation searching of the included articles using Web of Science, and manual searching of the last 6 months of principal otology journals. One-hundred and thirty-two records were included in the review and the information related to peripheral and central mechanisms of tinnitus pathophysiology was collected in order to update on theories and models. A narrative synthesis examined the main themes arising from this information. Tinnitus pathophysiology is complex and multifactorial, involving the auditory and non-auditory systems. Recent theories assume the necessary involvement of extra-auditory brain regions for tinnitus to reach consciousness. Tinnitus engages multiple active dynamic and overlapping networks. We conclude that advancing knowledge concerning the origin and maintenance of specific tinnitus subtypes origin and maintenance mechanisms is of paramount importance for identifying adequate treatment.",
journal = "Frontiers in Neuroscience",
title = "Pathophysiology of Subjective Tinnitus: Triggers and Maintenance",
volume = "12",
pages = "00866",
doi = "10.3389/fnins.2018.00866"
}
1
12
4
8

New complexity measures reveal that topographic loops of human alpha phase potentials are more complex in drowsy than in wake

Kalauzi, Aleksandar; Vučković, Aleksandra; Bojić, Tijana

(2018)

TY  - JOUR
AU  - Kalauzi, Aleksandar
AU  - Vučković, Aleksandra
AU  - Bojić, Tijana
PY  - 2018
UR  - http://link.springer.com/10.1007/s11517-017-1746-3
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/7746
AB  - A number of measures, stemming from nonlinear dynamics, exist to estimate complexity of biomedical objects. In most cases they are appropriate, but sometimes unconventional measures, more suited for specific objects, are needed to perform the task. In our present work, we propose three new complexity measures to quantify complexity of topographic closed loops of alpha carrier frequency phase potentials (CFPP) of healthy humans in wake and drowsy states. EEG of ten adult individuals was recorded in both states, using a 14-channel montage. For each subject and each state, a topographic loop (circular directed graph) was constructed according to CFPP values. Circular complexity measure was obtained by summing angles which directed graph edges (arrows) form with the topographic center. Longitudinal complexity was defined as the sum of all arrow lengths, while intersecting complexity was introduced by counting the number of intersections of graph edges. Wilcoxon's signed-ranks test was used on the sets of these three measures, as well as on fractal dimension values of some loop properties, to test differences between loops obtained in wake vs. drowsy. While fractal dimension values were not significantly different, longitudinal and intersecting complexities, as well as anticlockwise circularity, were significantly increased in drowsy.
T2  - Medical & Biological Engineering & Computing
T1  - New complexity measures reveal that topographic loops of human alpha phase potentials are more complex in drowsy than in wake
VL  - 56
IS  - 6
SP  - 967
EP  - 978
DO  - 10.1007/s11517-017-1746-3
ER  - 
@article{
author = "Kalauzi, Aleksandar and Vučković, Aleksandra and Bojić, Tijana",
year = "2018",
url = "http://link.springer.com/10.1007/s11517-017-1746-3, http://vinar.vin.bg.ac.rs/handle/123456789/7746",
abstract = "A number of measures, stemming from nonlinear dynamics, exist to estimate complexity of biomedical objects. In most cases they are appropriate, but sometimes unconventional measures, more suited for specific objects, are needed to perform the task. In our present work, we propose three new complexity measures to quantify complexity of topographic closed loops of alpha carrier frequency phase potentials (CFPP) of healthy humans in wake and drowsy states. EEG of ten adult individuals was recorded in both states, using a 14-channel montage. For each subject and each state, a topographic loop (circular directed graph) was constructed according to CFPP values. Circular complexity measure was obtained by summing angles which directed graph edges (arrows) form with the topographic center. Longitudinal complexity was defined as the sum of all arrow lengths, while intersecting complexity was introduced by counting the number of intersections of graph edges. Wilcoxon's signed-ranks test was used on the sets of these three measures, as well as on fractal dimension values of some loop properties, to test differences between loops obtained in wake vs. drowsy. While fractal dimension values were not significantly different, longitudinal and intersecting complexities, as well as anticlockwise circularity, were significantly increased in drowsy.",
journal = "Medical & Biological Engineering & Computing",
title = "New complexity measures reveal that topographic loops of human alpha phase potentials are more complex in drowsy than in wake",
volume = "56",
number = "6",
pages = "967-978",
doi = "10.1007/s11517-017-1746-3"
}

Identification of Candidate Allosteric Modulators of the M1 Muscarinic Acetylcholine Receptor Which May Improve Vagus Nerve Stimulation in ChronicTinnitus

Bojić, Tijana; Perović, Vladimir R.; Senćanski, Milan V.; Glišić, Sanja

(2017)

TY  - JOUR
AU  - Bojić, Tijana
AU  - Perović, Vladimir R.
AU  - Senćanski, Milan V.
AU  - Glišić, Sanja
PY  - 2017
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/1823
AB  - Chronic tinnitus is characterized by neuroplastic changes of the auditory cortex. A promising method for therapy of chronic tinnitus is vagus nerve stimulation (VNS) combined with auditory stimulation. The principle of VNS is reversal of pathological neuroplastic changes of the auditory cortex toward physiological neural activity and synchronicity. The VNS mechanism of action in chronic tinnitus patients is prevailingly through the muscarinic neuromodulation of the auditory cortex by the activation of nc. basalis Meynerti. The aim of this study is to propose potential pharmaceutics which may improve the neuromodulatory effects of VNS. The working hypothesis is that M1 receptors have a dominant role in the neural plasticity of the auditory cortex. We propose that allosteric agonists of the muscarinic receptor type 1 (M1) receptor could improve specificity and selectivity of the neuromodulatory effect of VNS on the auditory cortex of chronic tinnitus patients even in the circumstances of lower acetylcholine brain concentration. This intervention would also reinforce the re-learning process of tinnitus (sub) networks by acting on cholinergic memory and learning mechanisms. We performed in silico screening of drug space using the EIIP/AQVN filter and selected 50 drugs as candidates for allosteric modulators of muscarinic receptors. Further filtering of these compounds by means of 3D QSAR and docking revealed 3 approved drugs-bromazepam, estazolam and flumazenil as the most promising candidates for combined chronic tinnitus therapy. These drugs should be further evaluated by biological tests and clinical trials.
T2  - Frontiers in Neuroscience
T1  - Identification of Candidate Allosteric Modulators of the M1 Muscarinic Acetylcholine Receptor Which May Improve Vagus Nerve Stimulation in ChronicTinnitus
VL  - 11
DO  - 10.3389/fnins.2017.00636
ER  - 
@article{
author = "Bojić, Tijana and Perović, Vladimir R. and Senćanski, Milan V. and Glišić, Sanja",
year = "2017",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/1823",
abstract = "Chronic tinnitus is characterized by neuroplastic changes of the auditory cortex. A promising method for therapy of chronic tinnitus is vagus nerve stimulation (VNS) combined with auditory stimulation. The principle of VNS is reversal of pathological neuroplastic changes of the auditory cortex toward physiological neural activity and synchronicity. The VNS mechanism of action in chronic tinnitus patients is prevailingly through the muscarinic neuromodulation of the auditory cortex by the activation of nc. basalis Meynerti. The aim of this study is to propose potential pharmaceutics which may improve the neuromodulatory effects of VNS. The working hypothesis is that M1 receptors have a dominant role in the neural plasticity of the auditory cortex. We propose that allosteric agonists of the muscarinic receptor type 1 (M1) receptor could improve specificity and selectivity of the neuromodulatory effect of VNS on the auditory cortex of chronic tinnitus patients even in the circumstances of lower acetylcholine brain concentration. This intervention would also reinforce the re-learning process of tinnitus (sub) networks by acting on cholinergic memory and learning mechanisms. We performed in silico screening of drug space using the EIIP/AQVN filter and selected 50 drugs as candidates for allosteric modulators of muscarinic receptors. Further filtering of these compounds by means of 3D QSAR and docking revealed 3 approved drugs-bromazepam, estazolam and flumazenil as the most promising candidates for combined chronic tinnitus therapy. These drugs should be further evaluated by biological tests and clinical trials.",
journal = "Frontiers in Neuroscience",
title = "Identification of Candidate Allosteric Modulators of the M1 Muscarinic Acetylcholine Receptor Which May Improve Vagus Nerve Stimulation in ChronicTinnitus",
volume = "11",
doi = "10.3389/fnins.2017.00636"
}
2
3
3
3

Generalized Poincare Plots-A New Method for Evaluation of Regimes in Cardiac Neural Control in Atrial Fibrillation and Healthy Subjects

Platiša, Mirjana M.; Bojić, Tijana; Pavlovic, Sinisa U.; Radovanovic, Nikola N.; Kalauzi, Aleksandar

(2016)

TY  - JOUR
AU  - Platiša, Mirjana M.
AU  - Bojić, Tijana
AU  - Pavlovic, Sinisa U.
AU  - Radovanovic, Nikola N.
AU  - Kalauzi, Aleksandar
PY  - 2016
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/941
AB  - Classical Poincare plot is a standard way to measure nonlinear regulation of cardiovascular control. In our work we propose a generalized form of Poincare plot where we track correlation between the duration of j preceding and k next RR intervals. The investigation was done in healthy subjects and patients with atrial fibrillation, by varying j,k LT = 100. In cases where j = k, in healthy subjects the typical pattern was observed by paths that were substituting scatterplots and that were initiated and ended by loops of Poincare plot points. This was not the case for atrial fibrillation patients where Poincare plot had a simple scattered form. More, a typical matrix of Pearsons correlation coefficients, r(j,k), showed different positions of local maxima, depending on the subjects health condition. In both groups, local maxima were grouped into four clusters which probably determined specific regulatory mechanisms according to correlations between the duration of symmetric and asymmetric observed RR intervals. We quantified matrices degrees of asymmetry and found that they were significantly different: distributed around zero in healthy, while being negative in atrial fibrillation. Also, Pearsons coefficients were higher in healthy than in atrial fibrillation or in signals with reshuffled intervals. Our hypothesis is that by this novel method we can observe heart rate regimes typical for baseline conditions and defense reaction in healthy subjects. These data indicate that neural control mechanisms of heart rate are operating in healthy subjects in contrast with atrial fibrillation, identifying it as the state of risk for stress-dependent pathologies. Regulatory regimes of heart rate can be further quantified and explored by the proposed novel method.
T2  - Frontiers in Neuroscience
T1  - Generalized Poincare Plots-A New Method for Evaluation of Regimes in Cardiac Neural Control in Atrial Fibrillation and Healthy Subjects
VL  - 10
DO  - 10.3389/fnins.2016.00038
ER  - 
@article{
author = "Platiša, Mirjana M. and Bojić, Tijana and Pavlovic, Sinisa U. and Radovanovic, Nikola N. and Kalauzi, Aleksandar",
year = "2016",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/941",
abstract = "Classical Poincare plot is a standard way to measure nonlinear regulation of cardiovascular control. In our work we propose a generalized form of Poincare plot where we track correlation between the duration of j preceding and k next RR intervals. The investigation was done in healthy subjects and patients with atrial fibrillation, by varying j,k LT = 100. In cases where j = k, in healthy subjects the typical pattern was observed by paths that were substituting scatterplots and that were initiated and ended by loops of Poincare plot points. This was not the case for atrial fibrillation patients where Poincare plot had a simple scattered form. More, a typical matrix of Pearsons correlation coefficients, r(j,k), showed different positions of local maxima, depending on the subjects health condition. In both groups, local maxima were grouped into four clusters which probably determined specific regulatory mechanisms according to correlations between the duration of symmetric and asymmetric observed RR intervals. We quantified matrices degrees of asymmetry and found that they were significantly different: distributed around zero in healthy, while being negative in atrial fibrillation. Also, Pearsons coefficients were higher in healthy than in atrial fibrillation or in signals with reshuffled intervals. Our hypothesis is that by this novel method we can observe heart rate regimes typical for baseline conditions and defense reaction in healthy subjects. These data indicate that neural control mechanisms of heart rate are operating in healthy subjects in contrast with atrial fibrillation, identifying it as the state of risk for stress-dependent pathologies. Regulatory regimes of heart rate can be further quantified and explored by the proposed novel method.",
journal = "Frontiers in Neuroscience",
title = "Generalized Poincare Plots-A New Method for Evaluation of Regimes in Cardiac Neural Control in Atrial Fibrillation and Healthy Subjects",
volume = "10",
doi = "10.3389/fnins.2016.00038"
}
1
8
8
9

Uncoupling of cardiac and respiratory rhythm in atrial fibrillation

Platiša, Mirjana M.; Bojić, Tijana; Pavlovic, Sinisa U.; Radovanovic, Nikola N.; Kalauzi, Aleksandar

(2016)

TY  - JOUR
AU  - Platiša, Mirjana M.
AU  - Bojić, Tijana
AU  - Pavlovic, Sinisa U.
AU  - Radovanovic, Nikola N.
AU  - Kalauzi, Aleksandar
PY  - 2016
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/1332
AB  - Rearranged origin of heart rhythm in patients with atrial fibrillation (AF) influences the regulation of the heart and consequently the respiratory rhythm, and the bidirectional interaction of these rhythms not documented. Hence, we examined coupling of the RR interval and the respiration (Resp) signal by coherence, Granger causality and the cross-sample entropy method of time series analysis in patients with AF and a healthy control group. In healthy subjects, the influence of respiration on cardiac rhythm was found as increased coherence at the breathing frequency (BF) range, significantly stronger interaction and synchrony from Resp to RR than from RR to Resp. On the contrary, in patients with AF, coherence at BF diminished, there were no causal interactions between signals in both directions, which resulted in equally great asynchrony between them. In AF, the absence of full functionality of the sinoatrial node, as an integrator of neural cardiac control, resulted in diminished vagal modulation of heart periods and consequently impaired bidirectional cardio-respiratory interaction.
T2  - Biomedical Engineering / Biomedizinische Technik
T1  - Uncoupling of cardiac and respiratory rhythm in atrial fibrillation
VL  - 61
IS  - 6
SP  - 657
EP  - 663
DO  - 10.1515/bmt-2016-0057
ER  - 
@article{
author = "Platiša, Mirjana M. and Bojić, Tijana and Pavlovic, Sinisa U. and Radovanovic, Nikola N. and Kalauzi, Aleksandar",
year = "2016",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/1332",
abstract = "Rearranged origin of heart rhythm in patients with atrial fibrillation (AF) influences the regulation of the heart and consequently the respiratory rhythm, and the bidirectional interaction of these rhythms not documented. Hence, we examined coupling of the RR interval and the respiration (Resp) signal by coherence, Granger causality and the cross-sample entropy method of time series analysis in patients with AF and a healthy control group. In healthy subjects, the influence of respiration on cardiac rhythm was found as increased coherence at the breathing frequency (BF) range, significantly stronger interaction and synchrony from Resp to RR than from RR to Resp. On the contrary, in patients with AF, coherence at BF diminished, there were no causal interactions between signals in both directions, which resulted in equally great asynchrony between them. In AF, the absence of full functionality of the sinoatrial node, as an integrator of neural cardiac control, resulted in diminished vagal modulation of heart periods and consequently impaired bidirectional cardio-respiratory interaction.",
journal = "Biomedical Engineering / Biomedizinische Technik",
title = "Uncoupling of cardiac and respiratory rhythm in atrial fibrillation",
volume = "61",
number = "6",
pages = "657-663",
doi = "10.1515/bmt-2016-0057"
}
10
10
8

Common molecular mechanism of the hepatic lesion and the cardiac parasympathetic regulation in chronic hepatitis C infection: a critical role for the muscarinic receptor type 3

Glišić, Sanja; Cavanaugh, David P.; Chittur, Krishnan K.; Senćanski, Milan V.; Perović, Vladimir R.; Bojić, Tijana

(2016)

TY  - JOUR
AU  - Glišić, Sanja
AU  - Cavanaugh, David P.
AU  - Chittur, Krishnan K.
AU  - Senćanski, Milan V.
AU  - Perović, Vladimir R.
AU  - Bojić, Tijana
PY  - 2016
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/977
AB  - Background: The pathophysiological overlapping between Sjorgens Syndrome (SS) and HCV, presence of anti-muscarinic receptor type 3 (M3R) antibodies in SS, the role that M3R plays in the regulation of the heart rate, has led to the assumption that cardiovagal dysfunction in HCV patients is caused by anti-M3R antibodies elicited by HCV proteins or by their direct interaction with M3R. Results: To identify HCV protein which possibly is crossreactive with M3R or which binds to this receptor, we performed the Informational Spectrum Method (ISM) analysis of the HCV proteome. This analysis revealed that NS5A protein represents the most probable interactor of M3R or that this viral protein could elicit antibodies which modulate function of this receptor. Further detailed structure/function analysis of NS5A and M3R performed by the ISM method extended with other Digital Signal processing (DSP) approaches revealed domains of these proteins which participate in their crossreactivity or in their direct interaction, representing promising diagnostic and therapeutic targets. Conclusions: Application of the ISM with other compatible bioinformatics methods offers new perspectives for identifying diagnostic and therapeutic targets for complicated forms of HCV and other viral infections. We show how the electron-ion interaction potential (EIIP) amino-acid scale used in the ISM combined with a robust, high performance hydrophobicity scale can provide new insights for understanding protein structure/function and protein-protein interactions.
T2  - BMC Bioinformatics
T1  - Common molecular mechanism of the hepatic lesion and the cardiac parasympathetic regulation in chronic hepatitis C infection: a critical role for the muscarinic receptor type 3
VL  - 17
DO  - 10.1186/s12859-016-0988-7
ER  - 
@article{
author = "Glišić, Sanja and Cavanaugh, David P. and Chittur, Krishnan K. and Senćanski, Milan V. and Perović, Vladimir R. and Bojić, Tijana",
year = "2016",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/977",
abstract = "Background: The pathophysiological overlapping between Sjorgens Syndrome (SS) and HCV, presence of anti-muscarinic receptor type 3 (M3R) antibodies in SS, the role that M3R plays in the regulation of the heart rate, has led to the assumption that cardiovagal dysfunction in HCV patients is caused by anti-M3R antibodies elicited by HCV proteins or by their direct interaction with M3R. Results: To identify HCV protein which possibly is crossreactive with M3R or which binds to this receptor, we performed the Informational Spectrum Method (ISM) analysis of the HCV proteome. This analysis revealed that NS5A protein represents the most probable interactor of M3R or that this viral protein could elicit antibodies which modulate function of this receptor. Further detailed structure/function analysis of NS5A and M3R performed by the ISM method extended with other Digital Signal processing (DSP) approaches revealed domains of these proteins which participate in their crossreactivity or in their direct interaction, representing promising diagnostic and therapeutic targets. Conclusions: Application of the ISM with other compatible bioinformatics methods offers new perspectives for identifying diagnostic and therapeutic targets for complicated forms of HCV and other viral infections. We show how the electron-ion interaction potential (EIIP) amino-acid scale used in the ISM combined with a robust, high performance hydrophobicity scale can provide new insights for understanding protein structure/function and protein-protein interactions.",
journal = "BMC Bioinformatics",
title = "Common molecular mechanism of the hepatic lesion and the cardiac parasympathetic regulation in chronic hepatitis C infection: a critical role for the muscarinic receptor type 3",
volume = "17",
doi = "10.1186/s12859-016-0988-7"
}
4
4
5

In silico Therapeutics for Neurogenic Hypertension and Vasovagal Syncope

Bojić, Tijana; Perović, Vladimir R.; Glišić, Sanja

(2016)

TY  - JOUR
AU  - Bojić, Tijana
AU  - Perović, Vladimir R.
AU  - Glišić, Sanja
PY  - 2016
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/900
AB  - Neurocardiovascular diseases (NCVD) are the leading cause of death in the developed world and will remain so till 2020. In these diseases the pathologically changed nervous control of cardiovascular system has the central role. The actual NCV syndromes are neurogenic hypertension, representing the sympathetically mediated disorder, and vasovagal syncope, which is the vagally mediated disorders. Vasovagal syncope, the disease far from its etiological treatment, could benefit from recruiting and application of antimuscarinic drugs used in other parasympathetic disorders. The informational spectrum method (ISM), a method widely applied for the characterization of protein-protein interactions in the field of immunology, endocrinology and anti HIV drug discovery, was applied for the first time in the analysis of neurogenic hypertension and vasovagal syncope therapeutic targets. In silico analysis revealed the potential involvement of apelin in neurogenic hypertension. Applying the EIIP/ISM bioinformatics concept in investigation of drugs for treatment of vasovagal syncope suggests that 78% of tested antimuscarinic drugs could have anti vasovagal syncope effect. The presented results confirm that ISM is a promissing method for investigation of molecular mechanisms underlying pathophysiological proceses of NCV syndromes and discovery of therapeutics targets for their treatment.
T2  - Frontiers in Neuroscience
T1  - In silico Therapeutics for Neurogenic Hypertension and Vasovagal Syncope
VL  - 9
DO  - 10.3389/fnins.2015.00520
ER  - 
@article{
author = "Bojić, Tijana and Perović, Vladimir R. and Glišić, Sanja",
year = "2016",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/900",
abstract = "Neurocardiovascular diseases (NCVD) are the leading cause of death in the developed world and will remain so till 2020. In these diseases the pathologically changed nervous control of cardiovascular system has the central role. The actual NCV syndromes are neurogenic hypertension, representing the sympathetically mediated disorder, and vasovagal syncope, which is the vagally mediated disorders. Vasovagal syncope, the disease far from its etiological treatment, could benefit from recruiting and application of antimuscarinic drugs used in other parasympathetic disorders. The informational spectrum method (ISM), a method widely applied for the characterization of protein-protein interactions in the field of immunology, endocrinology and anti HIV drug discovery, was applied for the first time in the analysis of neurogenic hypertension and vasovagal syncope therapeutic targets. In silico analysis revealed the potential involvement of apelin in neurogenic hypertension. Applying the EIIP/ISM bioinformatics concept in investigation of drugs for treatment of vasovagal syncope suggests that 78% of tested antimuscarinic drugs could have anti vasovagal syncope effect. The presented results confirm that ISM is a promissing method for investigation of molecular mechanisms underlying pathophysiological proceses of NCV syndromes and discovery of therapeutics targets for their treatment.",
journal = "Frontiers in Neuroscience",
title = "In silico Therapeutics for Neurogenic Hypertension and Vasovagal Syncope",
volume = "9",
doi = "10.3389/fnins.2015.00520"
}
2
1
3
2

Genetic Polymorphisms of Neurocardiovascular Disorders

Bojić, Tijana; Milovanović, Branislav; Jovanović-Ćupić, Snežana P.

(2015)

TY  - JOUR
AU  - Bojić, Tijana
AU  - Milovanović, Branislav
AU  - Jovanović-Ćupić, Snežana P.
PY  - 2015
UR  - http://www.archivesofmedicine.com/abstract/genetic-polymorphisms-of-neurocardiovascular-disorders-6481.html
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/8409
AB  - The autonomic nervous control of cardiovascular (CV) system plays a major role in the adaptation of the organism to the changes in external and internal environment. It’s dysfunction is the major pathophysiological factor in the development of neurocardiovascular diseases. The aim of this review is to present the state of the art on the role of candidate gene polymorphisms of the molecules in the signaling chain of neurocardiovascular transmission in neurocardiovascular diseases. Neurocardiovascular disorders can be classified as sympathetic vs. vagally mediated disorders, though in many disorders both systems are dysfunctional. A number of molecules along the signaling pathway can be functionally modified and be the background of the predisposition, faster progression or complicated form of the disease. When the disease is the consequence of the joined parasympathetic and sympathetic nervous system disequilibrium, the focus of neurogenetic research should be on molecules providing the cross-talk between the two systems: on intercellular and intracellular level and on the level of the signaling process integration. An aggregation of positive results for the association between certain genes and different neurocardiovascular phenotypes pointed on a specific "neurocardiovascular genetic hotspots". Identification of these genes could be of particular interest as a diagnostic tool in the clustered form of neurocardiovascular diseases. New data obtained from neurogenetic approach will improve the disease outcome by gene, pharmacologic and behavioral modulation of the autonomic nervous system.
T2  - Archives of Medicine
T1  - Genetic Polymorphisms of Neurocardiovascular Disorders
VL  - 7
IS  - 2
ER  - 
@article{
author = "Bojić, Tijana and Milovanović, Branislav and Jovanović-Ćupić, Snežana P.",
year = "2015",
url = "http://www.archivesofmedicine.com/abstract/genetic-polymorphisms-of-neurocardiovascular-disorders-6481.html, http://vinar.vin.bg.ac.rs/handle/123456789/8409",
abstract = "The autonomic nervous control of cardiovascular (CV) system plays a major role in the adaptation of the organism to the changes in external and internal environment. It’s dysfunction is the major pathophysiological factor in the development of neurocardiovascular diseases. The aim of this review is to present the state of the art on the role of candidate gene polymorphisms of the molecules in the signaling chain of neurocardiovascular transmission in neurocardiovascular diseases. Neurocardiovascular disorders can be classified as sympathetic vs. vagally mediated disorders, though in many disorders both systems are dysfunctional. A number of molecules along the signaling pathway can be functionally modified and be the background of the predisposition, faster progression or complicated form of the disease. When the disease is the consequence of the joined parasympathetic and sympathetic nervous system disequilibrium, the focus of neurogenetic research should be on molecules providing the cross-talk between the two systems: on intercellular and intracellular level and on the level of the signaling process integration. An aggregation of positive results for the association between certain genes and different neurocardiovascular phenotypes pointed on a specific "neurocardiovascular genetic hotspots". Identification of these genes could be of particular interest as a diagnostic tool in the clustered form of neurocardiovascular diseases. New data obtained from neurogenetic approach will improve the disease outcome by gene, pharmacologic and behavioral modulation of the autonomic nervous system.",
journal = "Archives of Medicine",
title = "Genetic Polymorphisms of Neurocardiovascular Disorders",
volume = "7",
number = "2"
}

Topographic distribution of EEG alpha attractor correlation dimension values in wake and drowsy states in humans

Kalauzi, Aleksandar; Vučković, Aleksandra; Bojić, Tijana

(2015)

TY  - JOUR
AU  - Kalauzi, Aleksandar
AU  - Vučković, Aleksandra
AU  - Bojić, Tijana
PY  - 2015
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/475
AB  - Organization of resting state cortical networks is of fundamental importance for the phenomenon of awareness, which is altered in the first part of hypnagogic period (Hori stages 1-4). Our aim was to investigate the change in brain topography pattern of EEG alpha attractor correlation dimension (CD) in the period of transition from Hori stage 1 to 4. EEG of ten healthy adult individuals was recorded in the wake and drowsy states, using a 14 channel average reference montage, from which 91 bipolar channels were derived and filtered in the wider alpha (6-14 Hz) range. Sixty 1 s long epochs of each state and individual were subjected to CD calculation according to the Grassberger-Procaccia method. For such a collection of signals, two embedding dimensions, d = {5,10}, and 22 time delays 7 = 2-23 samples were explored. Optimal values were d = 10 and 7 = 18, where both saturation and second zero crossing of the autocorrelation function occurred. Bipolar channel CD underwent a significant decrease during the transition and showed a positive linear correlation with electrode distance, stronger in the wake individuals. Topographic distribution of bipolar channels with above median CD changed from longitudinal anterior-posterior pattern (awake) to a more diagonal pattern, with localization in posterior regions (drowsiness). Our data are in line with the literature reporting functional segregation of neuronal assemblies in anterior and posterior regions during this transition. Our results should contribute to understanding of complex reorganization of the cortical part of alpha generators during the wake/drowsy transition. (C) 2014 Elsevier B.V. All rights reserved.
T2  - International Journal of Psychophysiology
T1  - Topographic distribution of EEG alpha attractor correlation dimension values in wake and drowsy states in humans
VL  - 95
IS  - 3
SP  - 278
EP  - 291
DO  - 10.1016/j.ijpsycho.2014.11.008
ER  - 
@article{
author = "Kalauzi, Aleksandar and Vučković, Aleksandra and Bojić, Tijana",
year = "2015",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/475",
abstract = "Organization of resting state cortical networks is of fundamental importance for the phenomenon of awareness, which is altered in the first part of hypnagogic period (Hori stages 1-4). Our aim was to investigate the change in brain topography pattern of EEG alpha attractor correlation dimension (CD) in the period of transition from Hori stage 1 to 4. EEG of ten healthy adult individuals was recorded in the wake and drowsy states, using a 14 channel average reference montage, from which 91 bipolar channels were derived and filtered in the wider alpha (6-14 Hz) range. Sixty 1 s long epochs of each state and individual were subjected to CD calculation according to the Grassberger-Procaccia method. For such a collection of signals, two embedding dimensions, d = {5,10}, and 22 time delays 7 = 2-23 samples were explored. Optimal values were d = 10 and 7 = 18, where both saturation and second zero crossing of the autocorrelation function occurred. Bipolar channel CD underwent a significant decrease during the transition and showed a positive linear correlation with electrode distance, stronger in the wake individuals. Topographic distribution of bipolar channels with above median CD changed from longitudinal anterior-posterior pattern (awake) to a more diagonal pattern, with localization in posterior regions (drowsiness). Our data are in line with the literature reporting functional segregation of neuronal assemblies in anterior and posterior regions during this transition. Our results should contribute to understanding of complex reorganization of the cortical part of alpha generators during the wake/drowsy transition. (C) 2014 Elsevier B.V. All rights reserved.",
journal = "International Journal of Psychophysiology",
title = "Topographic distribution of EEG alpha attractor correlation dimension values in wake and drowsy states in humans",
volume = "95",
number = "3",
pages = "278-291",
doi = "10.1016/j.ijpsycho.2014.11.008"
}
8
8
9

RR interval-respiratory signal waveform modeling in human slow paced and spontaneous breathing

Kapidžić, Ana; Platiša, Mirjana M.; Bojić, Tijana; Kalauzi, Aleksandar

(2014)

TY  - JOUR
AU  - Kapidžić, Ana
AU  - Platiša, Mirjana M.
AU  - Bojić, Tijana
AU  - Kalauzi, Aleksandar
PY  - 2014
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/188
AB  - Our aim was to model the dependence of respiratory sinus arrhythmia (RSA) on the respiratory waveform and to elucidate underlying mechanisms of cardiorespiratory coupling. In 30 subjects, RR interval and respiratory signal were recorded during spontaneous and paced (0.1 Hz/0.15 Hz) breathing and their relationship was modeled by a first order linear differential equation. This model has two parameters: a0 (related to the instantaneous degree of abdominal expansion) and a1 (referring to the speed of abdominal expansion). Assuming that a0 represents slowly adapting pulmonary stretch receptors (SARs) and a1 SARs in coordination with other stretch receptors and central integrative coupling; then pulmonary stretch receptors relaying the instantaneous lung volume are the major factor determining cardiovagal output during inspiration. The models results depended on breathing frequency with the least error occurring during slow paced breathing. The role of vagal afferent neurons in cardiorespiratory coupling may relate to neurocardiovascular diseases in which weakened coupling among venous return, arterial pressure, heart rate and respiration produces cardiovagal instability. (C) 2014 Elsevier B.V. All rights reserved.
T2  - Respiratory Physiology and Neurobiology
T1  - RR interval-respiratory signal waveform modeling in human slow paced and spontaneous breathing
VL  - 203
SP  - 51
EP  - 59
DO  - 10.1016/j.resp.2014.08.004
ER  - 
@article{
author = "Kapidžić, Ana and Platiša, Mirjana M. and Bojić, Tijana and Kalauzi, Aleksandar",
year = "2014",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/188",
abstract = "Our aim was to model the dependence of respiratory sinus arrhythmia (RSA) on the respiratory waveform and to elucidate underlying mechanisms of cardiorespiratory coupling. In 30 subjects, RR interval and respiratory signal were recorded during spontaneous and paced (0.1 Hz/0.15 Hz) breathing and their relationship was modeled by a first order linear differential equation. This model has two parameters: a0 (related to the instantaneous degree of abdominal expansion) and a1 (referring to the speed of abdominal expansion). Assuming that a0 represents slowly adapting pulmonary stretch receptors (SARs) and a1 SARs in coordination with other stretch receptors and central integrative coupling; then pulmonary stretch receptors relaying the instantaneous lung volume are the major factor determining cardiovagal output during inspiration. The models results depended on breathing frequency with the least error occurring during slow paced breathing. The role of vagal afferent neurons in cardiorespiratory coupling may relate to neurocardiovascular diseases in which weakened coupling among venous return, arterial pressure, heart rate and respiration produces cardiovagal instability. (C) 2014 Elsevier B.V. All rights reserved.",
journal = "Respiratory Physiology and Neurobiology",
title = "RR interval-respiratory signal waveform modeling in human slow paced and spontaneous breathing",
volume = "203",
pages = "51-59",
doi = "10.1016/j.resp.2014.08.004"
}
4
5
5

Nonlinear properties of cardiac rhythm and respiratory signal under paced breathing in young and middle-aged healthy subjects

Kapidžić, Ana; Platiša, Mirjana M.; Bojić, Tijana; Kalauzi, Aleksandar

(2014)

TY  - JOUR
AU  - Kapidžić, Ana
AU  - Platiša, Mirjana M.
AU  - Bojić, Tijana
AU  - Kalauzi, Aleksandar
PY  - 2014
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/338
AB  - We examined the effects of gender and age in young and middle-aged subjects on the level of cardiorespiratory interaction by analyzing properties of cardiac, respiratory and cardiac-respiratory regulatory mechanisms under paced breathing. In 56 healthy subjects, ECG (RR interval) and respiratory signal were simultaneously acquired in supine position at paced (0.1-0.45 Hz, steps of 0.05 Hz) and spontaneous breathing. The participants were divided into gender matched group of young adults (19-25 years old) and middle-aged adults (35-44 years old). Power spectral analysis was applied on RR interval time series and spectral components in very low frequency (VLF), low frequency (LF) and high frequency (HF) ranges were computed. We also calculated Sample entropy of RR interval series (SampEnRR), respiratory series (SampEnResp), and their cross-sample entropy (cross-SampEn). Under paced breathing, reduction of all spectral powers with age (p LT 0.05) is not gender dependent but reduction of some entropy measures is; SampEnRR and SampEnResp were lower only in men (p LT 0.05). In the middle-aged subjects, effect of gender on spectral measures is significant; males had lower HF (p LT 0.05). Pattern of dependencies of SampEn and cross-SampEn on paced breathing frequency were significantly different in men (young vs. middle-aged, p = 0.001 and p = 0.037) and in middle-aged subjects (females vs. males, p = 0.011 and p = 0.008). In middle-aged males, lower entropy measures indicated reduced and less complex partial cardiac and respiratory control, and central cardio-respiratory control. In conclusion, in healthy middle-aged subjects changes in cardio-respiratory coupling are detectable only in males. (C) 2014 IPEM. Published by Elsevier Ltd. All rights reserved.
T2  - Medical Engineering and Physics
T1  - Nonlinear properties of cardiac rhythm and respiratory signal under paced breathing in young and middle-aged healthy subjects
VL  - 36
IS  - 12
SP  - 1577
EP  - 1584
DO  - 10.1016/j.medengphy.2014.08.007
ER  - 
@article{
author = "Kapidžić, Ana and Platiša, Mirjana M. and Bojić, Tijana and Kalauzi, Aleksandar",
year = "2014",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/338",
abstract = "We examined the effects of gender and age in young and middle-aged subjects on the level of cardiorespiratory interaction by analyzing properties of cardiac, respiratory and cardiac-respiratory regulatory mechanisms under paced breathing. In 56 healthy subjects, ECG (RR interval) and respiratory signal were simultaneously acquired in supine position at paced (0.1-0.45 Hz, steps of 0.05 Hz) and spontaneous breathing. The participants were divided into gender matched group of young adults (19-25 years old) and middle-aged adults (35-44 years old). Power spectral analysis was applied on RR interval time series and spectral components in very low frequency (VLF), low frequency (LF) and high frequency (HF) ranges were computed. We also calculated Sample entropy of RR interval series (SampEnRR), respiratory series (SampEnResp), and their cross-sample entropy (cross-SampEn). Under paced breathing, reduction of all spectral powers with age (p LT 0.05) is not gender dependent but reduction of some entropy measures is; SampEnRR and SampEnResp were lower only in men (p LT 0.05). In the middle-aged subjects, effect of gender on spectral measures is significant; males had lower HF (p LT 0.05). Pattern of dependencies of SampEn and cross-SampEn on paced breathing frequency were significantly different in men (young vs. middle-aged, p = 0.001 and p = 0.037) and in middle-aged subjects (females vs. males, p = 0.011 and p = 0.008). In middle-aged males, lower entropy measures indicated reduced and less complex partial cardiac and respiratory control, and central cardio-respiratory control. In conclusion, in healthy middle-aged subjects changes in cardio-respiratory coupling are detectable only in males. (C) 2014 IPEM. Published by Elsevier Ltd. All rights reserved.",
journal = "Medical Engineering and Physics",
title = "Nonlinear properties of cardiac rhythm and respiratory signal under paced breathing in young and middle-aged healthy subjects",
volume = "36",
number = "12",
pages = "1577-1584",
doi = "10.1016/j.medengphy.2014.08.007"
}
16
14
20

Response Factors to Pegylated Interferon-Alfa/Ribavirin Treatment in Chronic Hepatitis C Patients Genotype 1b

Jovanović-Ćupić, Snežana P.; Glišić, Sanja; Stanojevic, M.; Vasiljevic, N.; Bojić, Tijana; Božović, Ana M.; Dimitrijević, Bogomir B.

(2014)

TY  - JOUR
AU  - Jovanović-Ćupić, Snežana P.
AU  - Glišić, Sanja
AU  - Stanojevic, M.
AU  - Vasiljevic, N.
AU  - Bojić, Tijana
AU  - Božović, Ana M.
AU  - Dimitrijević, Bogomir B.
PY  - 2014
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/5858
AB  - Hepatitis C virus infection is the most common chronic blood-borne infection and one of the most important causes of chronic liver disease. Knowing the predictors associated with pegylated interferon/ribavirin (PEG-IFN/RBV) combination therapy response is important for evidence-based treatment recommendations. The goal of this study was to identify host and viral factors of response to PEG-IFN/RBV treatment in chronic hepatitis C genotype 1b patients. We have examined the relationship between gender, age, level of alanine aminotransferase (ALT), viral load and liver fibrosis progression on therapy response. ALT level and viral load were evaluated before starting treatment with combination therapy. The elevated levels of ALT and route of HCV transmission were found to be significantly associated with the response to therapy in HCV-infected patients. Our findings may be useful for estimating a patients likelihood Of achieving sustained viral response.
T2  - Archives of biological sciences
T1  - Response Factors to Pegylated Interferon-Alfa/Ribavirin Treatment in Chronic Hepatitis C Patients Genotype 1b
VL  - 66
IS  - 1
SP  - 193
EP  - 201
DO  - 10.2298/ABS1401193J
ER  - 
@article{
author = "Jovanović-Ćupić, Snežana P. and Glišić, Sanja and Stanojevic, M. and Vasiljevic, N. and Bojić, Tijana and Božović, Ana M. and Dimitrijević, Bogomir B.",
year = "2014",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/5858",
abstract = "Hepatitis C virus infection is the most common chronic blood-borne infection and one of the most important causes of chronic liver disease. Knowing the predictors associated with pegylated interferon/ribavirin (PEG-IFN/RBV) combination therapy response is important for evidence-based treatment recommendations. The goal of this study was to identify host and viral factors of response to PEG-IFN/RBV treatment in chronic hepatitis C genotype 1b patients. We have examined the relationship between gender, age, level of alanine aminotransferase (ALT), viral load and liver fibrosis progression on therapy response. ALT level and viral load were evaluated before starting treatment with combination therapy. The elevated levels of ALT and route of HCV transmission were found to be significantly associated with the response to therapy in HCV-infected patients. Our findings may be useful for estimating a patients likelihood Of achieving sustained viral response.",
journal = "Archives of biological sciences",
title = "Response Factors to Pegylated Interferon-Alfa/Ribavirin Treatment in Chronic Hepatitis C Patients Genotype 1b",
volume = "66",
number = "1",
pages = "193-201",
doi = "10.2298/ABS1401193J"
}
2

Influenza vaccine as prevention for cardiovascular diseases: Possible molecular mechanism

Veljković, Veljko; Glišić, Sanja; Veljković, Nevena V.; Bojić, Tijana; Dietrich, Ursula; Perović, Vladimir R.; Colombatti, Alfonso

(2014)

TY  - JOUR
AU  - Veljković, Veljko
AU  - Glišić, Sanja
AU  - Veljković, Nevena V.
AU  - Bojić, Tijana
AU  - Dietrich, Ursula
AU  - Perović, Vladimir R.
AU  - Colombatti, Alfonso
PY  - 2014
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/229
AB  - Despite plausible evidence for beneficial effects of the vaccination against influenza in cardiovascular diseases (CVD) very limited studies have been carried out to explain the molecular mechanism of this phenomenon. Using the informational spectrum method (ISM), a virtual spectroscopy method for analysis of protein-protein interactions, the bradykinin 2 receptor (BKB2R) was identified as a principal host protein which could mediate molecular processes underlying the cardioprotective effect of influenza vaccines. Based on this finding we suggest that some antibodies elicited by influenza vaccines act as agonists, which activate a BKB2R-associated signaling pathway contributing to the protection against CVD. The ISM analysis of 14 influenza viruses, which were used as components of seasonal vaccines, revealed four vaccine viruses A/Beijing/262/95(H1N1), A/NewCaledonia/20/1999(H1N1), A/Christchurch/28/2003(H3N2) and A/Perth/16/2009(H3N2), which could be suited best for further studies on the cardioprotective effect of influenza vaccines. (C) 2014 Elsevier Ltd. All rights reserved.
T2  - Vaccine
T1  - Influenza vaccine as prevention for cardiovascular diseases: Possible molecular mechanism
VL  - 32
IS  - 48
SP  - 6569
EP  - 6575
DO  - 10.1016/j.vaccine.2014.07.007
ER  - 
@article{
author = "Veljković, Veljko and Glišić, Sanja and Veljković, Nevena V. and Bojić, Tijana and Dietrich, Ursula and Perović, Vladimir R. and Colombatti, Alfonso",
year = "2014",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/229",
abstract = "Despite plausible evidence for beneficial effects of the vaccination against influenza in cardiovascular diseases (CVD) very limited studies have been carried out to explain the molecular mechanism of this phenomenon. Using the informational spectrum method (ISM), a virtual spectroscopy method for analysis of protein-protein interactions, the bradykinin 2 receptor (BKB2R) was identified as a principal host protein which could mediate molecular processes underlying the cardioprotective effect of influenza vaccines. Based on this finding we suggest that some antibodies elicited by influenza vaccines act as agonists, which activate a BKB2R-associated signaling pathway contributing to the protection against CVD. The ISM analysis of 14 influenza viruses, which were used as components of seasonal vaccines, revealed four vaccine viruses A/Beijing/262/95(H1N1), A/NewCaledonia/20/1999(H1N1), A/Christchurch/28/2003(H3N2) and A/Perth/16/2009(H3N2), which could be suited best for further studies on the cardioprotective effect of influenza vaccines. (C) 2014 Elsevier Ltd. All rights reserved.",
journal = "Vaccine",
title = "Influenza vaccine as prevention for cardiovascular diseases: Possible molecular mechanism",
volume = "32",
number = "48",
pages = "6569-6575",
doi = "10.1016/j.vaccine.2014.07.007"
}
54
29
26
28

Levels of presepsin and midregion-proadrenomedulin in septic patients with end-stage renal disease after cardiovascular surgery: 1-year follow up study

Maravic-Stojkovic, Vera; Lausevic-Vuk, L.; Jovic, M.; Filipovic, M.; Bojić, Tijana; Stojkovic, B.; Isenović, Esma R.; Djukanovic, B.

(2013)

TY  - CONF
AU  - Maravic-Stojkovic, Vera
AU  - Lausevic-Vuk, L.
AU  - Jovic, M.
AU  - Filipovic, M.
AU  - Bojić, Tijana
AU  - Stojkovic, B.
AU  - Isenović, Esma R.
AU  - Djukanovic, B.
PY  - 2013
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/5677
C3  - Infection
T1  - Levels of presepsin and midregion-proadrenomedulin in septic patients with end-stage renal disease after cardiovascular surgery: 1-year follow up study
VL  - 41
SP  - S33
EP  - S33
ER  - 
@conference{
author = "Maravic-Stojkovic, Vera and Lausevic-Vuk, L. and Jovic, M. and Filipovic, M. and Bojić, Tijana and Stojkovic, B. and Isenović, Esma R. and Djukanovic, B.",
year = "2013",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/5677",
journal = "Infection",
title = "Levels of presepsin and midregion-proadrenomedulin in septic patients with end-stage renal disease after cardiovascular surgery: 1-year follow up study",
volume = "41",
pages = "S33-S33"
}

The role of G protein coupled receptor kinases in neurocardiovascular pathophysiology

Bojić, Tijana; Sudar, Emina; Mikhailidis, Dimitri P.; Alavantić, Dragan; Isenović, Esma R.

(2012)

TY  - JOUR
AU  - Bojić, Tijana
AU  - Sudar, Emina
AU  - Mikhailidis, Dimitri P.
AU  - Alavantić, Dragan
AU  - Isenović, Esma R.
PY  - 2012
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/5232
AB  - In coronary artery disease the G protein related kinases (GRKs) play a role in desensitization of beta-adrenoreceptors (AR) after coronary occlusion. Targeted deletion and lowering of cardiac myocyte GRK-2 decreases the risk of post-ischemic heart failure (HF). Studies carried out in humans confirm the role of GRK-2 as a marker for the progression of HF after myocardial infarction (MI). The level of GRK-2 could be an indicator of beta-AR blocker efficacy in patients with acute coronary syndrome. Elevated levels of GRK-2 are an early ubiquitous consequence of myocardial injury. In hypertension an increased level of GRK-2 was reported in both animal models and human studies. The role of GRKs in vagally mediated disorders such as vasovagal syncope and atrial fibrillation remains controversial. The role of GRKs in the pathogenesis of neurocardiological diseases provides an insight into the molecular pathogenesis process, opens potential therapeutic options and suggests new directions for scientific research.
T2  - Archives of Medical Science
T1  - The role of G protein coupled receptor kinases in neurocardiovascular pathophysiology
VL  - 8
IS  - 6
SP  - 970
EP  - 977
DO  - 10.5114/aoms.2012.29996
ER  - 
@article{
author = "Bojić, Tijana and Sudar, Emina and Mikhailidis, Dimitri P. and Alavantić, Dragan and Isenović, Esma R.",
year = "2012",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/5232",
abstract = "In coronary artery disease the G protein related kinases (GRKs) play a role in desensitization of beta-adrenoreceptors (AR) after coronary occlusion. Targeted deletion and lowering of cardiac myocyte GRK-2 decreases the risk of post-ischemic heart failure (HF). Studies carried out in humans confirm the role of GRK-2 as a marker for the progression of HF after myocardial infarction (MI). The level of GRK-2 could be an indicator of beta-AR blocker efficacy in patients with acute coronary syndrome. Elevated levels of GRK-2 are an early ubiquitous consequence of myocardial injury. In hypertension an increased level of GRK-2 was reported in both animal models and human studies. The role of GRKs in vagally mediated disorders such as vasovagal syncope and atrial fibrillation remains controversial. The role of GRKs in the pathogenesis of neurocardiological diseases provides an insight into the molecular pathogenesis process, opens potential therapeutic options and suggests new directions for scientific research.",
journal = "Archives of Medical Science",
title = "The role of G protein coupled receptor kinases in neurocardiovascular pathophysiology",
volume = "8",
number = "6",
pages = "970-977",
doi = "10.5114/aoms.2012.29996"
}
9
10
9

Methodology of monitoring cardiovascular regulation

Bojić, Tijana; Radak, Đorđe J.; Putnikovic, Biljana; Alavantić, Dragan; Isenović, Esma R.

(2012)

@article{
author = "Bojić, Tijana and Radak, Đorđe J. and Putnikovic, Biljana and Alavantić, Dragan and Isenović, Esma R.",
year = "2012",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/5279",
journal = "Vojnosanitetski pregled",
title = "Methodology of monitoring cardiovascular regulation",
volume = "69",
number = "12",
pages = "1084-1090",
doi = "10.2298/VSP110707019B"
}
3
3
4

Modeling the relationship between Higuchis fractal dimension and Fourier spectra of physiological signals

Kalauzi, Aleksandar; Bojić, Tijana; Vučković, Aleksandra

(2012)

TY  - JOUR
AU  - Kalauzi, Aleksandar
AU  - Bojić, Tijana
AU  - Vučković, Aleksandra
PY  - 2012
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/4908
AB  - The exact mathematical relationship between FFT spectrum and fractal dimension (FD) of an experimentally recorded signal is not known. In this work, we tried to calculate signal FD directly from its Fourier amplitudes. First, dependence of Higuchis FD of mathematical sinusoids on their individual frequencies was modeled with a two-parameter exponential function. Next, FD of a finite sum of sinusoids was found to be a weighted average of their FDs, weighting factors being their Fourier amplitudes raised to a fractal degree. Exponent dependence on frequency was modeled with exponential, power and logarithmic functions. A set of 280 EEG signals and Weierstrass functions were analyzed. Cross-validation was done within EEG signals and between them and Weierstrass functions. Exponential dependence of fractal exponents on frequency was found to be the most accurate. In this work, signal FD was for the first time expressed as a fractal weighted average of FD values of its Fourier components, also allowing researchers to perform direct estimation of signal fractal dimension from its FFT spectrum.
T2  - Medical and Biological Engineering and Computing
T1  - Modeling the relationship between Higuchis fractal dimension and Fourier spectra of physiological signals
VL  - 50
IS  - 7
SP  - 689
EP  - 699
DO  - 10.1007/s11517-012-0913-9
ER  - 
@article{
author = "Kalauzi, Aleksandar and Bojić, Tijana and Vučković, Aleksandra",
year = "2012",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/4908",
abstract = "The exact mathematical relationship between FFT spectrum and fractal dimension (FD) of an experimentally recorded signal is not known. In this work, we tried to calculate signal FD directly from its Fourier amplitudes. First, dependence of Higuchis FD of mathematical sinusoids on their individual frequencies was modeled with a two-parameter exponential function. Next, FD of a finite sum of sinusoids was found to be a weighted average of their FDs, weighting factors being their Fourier amplitudes raised to a fractal degree. Exponent dependence on frequency was modeled with exponential, power and logarithmic functions. A set of 280 EEG signals and Weierstrass functions were analyzed. Cross-validation was done within EEG signals and between them and Weierstrass functions. Exponential dependence of fractal exponents on frequency was found to be the most accurate. In this work, signal FD was for the first time expressed as a fractal weighted average of FD values of its Fourier components, also allowing researchers to perform direct estimation of signal fractal dimension from its FFT spectrum.",
journal = "Medical and Biological Engineering and Computing",
title = "Modeling the relationship between Higuchis fractal dimension and Fourier spectra of physiological signals",
volume = "50",
number = "7",
pages = "689-699",
doi = "10.1007/s11517-012-0913-9"
}
11
9
10

EEG alpha phase shifts during transition from wakefulness to drowsiness

Kalauzi, Aleksandar; Vučković, Aleksandra; Bojić, Tijana

(2012)

TY  - JOUR
AU  - Kalauzi, Aleksandar
AU  - Vučković, Aleksandra
AU  - Bojić, Tijana
PY  - 2012
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/5215
AB  - Phases of alpha oscillations recorded by EEG were typically studied in the context of event or task related experiments, rarely during spontaneous alpha activity and in different brain states. During wake-to-drowsy transition they change unevenly, depending on the brain region. To explore their dynamics, we recorded ten adult healthy individuals in these two states. Alpha waves were treated as stable frequency and variable amplitude signals with one carrier frequency (CF). A method for calculating their CF phase shifts (CFPS) and CF phase potentials (CFPP) was developed and verified on surrogate signals as more accurate than phase shifts of Fourier components. Probability density estimate (PDE) of CFPS, CFPP and CF phase locking showed that frontal and fronto-temporal areas of the cortex underwent more extensive changes than posterior regions. The greatest differences were found between pairs of channels involving F7, F8, F3 and F4 (PDE of CFPS); F7, F8. T3 and 14 (CFPP); F7, F8, F3, F4, C3, C4 and T3 (decrease in CF phase locking). A topographic distribution of channels with above the average phase locking in the wake state revealed two separate regions occupying anterior and posterior brain areas (with intra regional and inter hemispheric connections). These regions merged and became mutually phase locked longitudinally in the drowsy state. Changes occurring primarily in the frontal and fronto-temporal regions correlated with an early decrease of alertness. Areas of increased phase locking might be correlated with topography of synchronous neuronal assemblies conceptualized within neural correlates of consciousness. (C) 2012 Elsevier B.V. All rights reserved.
T2  - International Journal of Psychophysiology
T1  - EEG alpha phase shifts during transition from wakefulness to drowsiness
VL  - 86
IS  - 3
SP  - 195
EP  - 205
DO  - 10.1016/j.ijpsycho.2012.04.012
ER  - 
@article{
author = "Kalauzi, Aleksandar and Vučković, Aleksandra and Bojić, Tijana",
year = "2012",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/5215",
abstract = "Phases of alpha oscillations recorded by EEG were typically studied in the context of event or task related experiments, rarely during spontaneous alpha activity and in different brain states. During wake-to-drowsy transition they change unevenly, depending on the brain region. To explore their dynamics, we recorded ten adult healthy individuals in these two states. Alpha waves were treated as stable frequency and variable amplitude signals with one carrier frequency (CF). A method for calculating their CF phase shifts (CFPS) and CF phase potentials (CFPP) was developed and verified on surrogate signals as more accurate than phase shifts of Fourier components. Probability density estimate (PDE) of CFPS, CFPP and CF phase locking showed that frontal and fronto-temporal areas of the cortex underwent more extensive changes than posterior regions. The greatest differences were found between pairs of channels involving F7, F8, F3 and F4 (PDE of CFPS); F7, F8. T3 and 14 (CFPP); F7, F8, F3, F4, C3, C4 and T3 (decrease in CF phase locking). A topographic distribution of channels with above the average phase locking in the wake state revealed two separate regions occupying anterior and posterior brain areas (with intra regional and inter hemispheric connections). These regions merged and became mutually phase locked longitudinally in the drowsy state. Changes occurring primarily in the frontal and fronto-temporal regions correlated with an early decrease of alertness. Areas of increased phase locking might be correlated with topography of synchronous neuronal assemblies conceptualized within neural correlates of consciousness. (C) 2012 Elsevier B.V. All rights reserved.",
journal = "International Journal of Psychophysiology",
title = "EEG alpha phase shifts during transition from wakefulness to drowsiness",
volume = "86",
number = "3",
pages = "195-205",
doi = "10.1016/j.ijpsycho.2012.04.012"
}
1
12
9
11