Jan Machal

Dr. Jan Machal

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Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 January 2019 in Orphanet Journal of Rare Diseases
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Journal Article
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RPRoman Panovský
Roman Panovský
MPMartin Pesl
Martin Pesl
THTomáš Holeček
Tomáš Holeček
JMJan Machal
Jan Machal
VFVěra Feitová
Věra Feitová
VKVladimír Kincl
Vladimír Kincl
The progressive cardiomyopathy that develops in boys with Duchenne and Becker muscular dystrophy (DMD/BMD) is presumed to be a secondary consequence of the fibrosis within the myocardium. There are only limited data on using parametric imaging in these patients. The purpose of this study was to assess native T1 and extracellular volume (ECV) values in DMD patients. The Czech population of males with DMD/BMD was screened. All eligible patients fulfilling the inclusion criteria were included. Forty nine males underwent cardiac magnetic resonance (MR) examination including T1 native and post-contrast mapping measurements. One DMD patient and all BMD patients were excluded from statistical analysis. Three groups were compared – Group D1 - DMD patients without late gadolinium enhancement (LGE) (n = 23), Group D2 - DMD patients with LGE (n = 20), and Group C – gender matched controls (n = 13). Compared to controls, both DMD groups had prolonged T1 native relaxation time. These results are concordant in all 6 segments as well as in global values (1041 ± 31 ms and 1043 ± 37 ms vs. 983 ± 15 ms, both p < 0.05). Group D2 had significantly increased global ECV (0.28 ± 0.044 vs. 0.243 ± 0.013, p < 0.05) and segmental ECV in inferolateral and anterolateral segments in comparison with controls. The results were also significant after adjustment for subjects’ age. DMD males had increased native T1 relaxation time independent of the presence or absence of myocardial fibrosis. Cardiac MR may provide clinically useful information even without contrast media administration.

1 March 2015 in Archives of Oral Biology
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Journal Article
Closed access
PLPetra Borilova Linhartova
Petra Borilova Linhartova
JBJirina Bartova
Jirina Bartova
HPHana Poskerova
Hana Poskerova
JMJan Machal
Jan Machal
JVJan Vokurka
Jan Vokurka
Lydie Izakovicova HollaLydie Izakovicova Holla
Lydie Izakovicova Holla

27 October 2023 in European Journal of Neurology
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Journal Article
Open access
VKVladimír Kincl
Vladimír Kincl
RPRoman Panovský
Roman Panovský
MBMartina Bočková
Martina Bočková
IRIvan Rektor
Ivan Rektor
MMMary Luz Mojica‐Pisciotti
Mary Luz Mojica‐Pisciotti
JMJan Machal
Jan Machal
Background: The known impairments of the cardiovascular system in Parkinson´s disease (PD) are caused by autonomic dysfunction and manifested mainly in postural hypotension, chronotropic insufficiency, and reduced heart rate variability. Other dysfunctions, mainly stress response, arrhythmia occurrence, and heart morphology changes, are still the subject of research.Objectives: To assess the heart rate and blood pressure reaction during exercise, advanced measurements of heart volumes and mass using cardiac magnetic resonance (CMR), and occurrence of arrhythmias in PD patients.Methods: Thirty PD patients (19 men, mean age 57.5 years) without known cardiac comorbidities underwent bicycle ergometry, electrocardiogram Holter monitoring and CMR. Exercise and CMR parameters were compared with controls (24 subjects for ergometry, 20 for CMR).Results: PD patients had lower baseline systolic blood pressure (SBP) (117.8 vs. 128.3 mmHg, p < 0.01), peak SBP (155.8 vs. 170.8 mmHg, p < 0.05), and lower heart rate increase (49.7 vs. 64.3 beats per minute, p < 0.01). PD patients had higher indexed left and right ventricular end‐diastolic volumes (68.5 vs. 57.3, p = 0.003 and 73.5 vs. 61.0 mL/m2, respectively) and also indexed left and right ventricular end‐systolic volumes (44.1 vs. 39.0, p = 0.013 and 29.0 vs. 22.0 mL/m2, p = 0.013, respectively). A high prevalence of atrial fibrillation (8 subjects, 26.7%) was found.Conclusions: This novel study combining functional and structural approaches showed that PD is linked with weaker blood pressure and heart rate reaction during exercise, increased myocardial mass and heart volumes compared to controls, and a high prevalence of atrial fibrillation.

1 December 2014 in Medicine
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Journal Article
Open access
JMJan Machal
Jan Machal
MPMonika Pávková-Goldbergová
Monika Pávková-Goldbergová
OHOta Hlinomaz
Ota Hlinomaz
LGLadislav Groch
Ladislav Groch
AVAnna Vašků
Anna Vašků
Genetic and non-genetic predictors of 15-year survival in patients with chronic three-vessel disease (3VD) were investigated. Coronary angiography was performed on 810 subjects with symptoms of stable ischemic heart disease in 1998. The patients with 3VD were genotyped for 23 candidate polymorphisms covering the PPAR-RXR pathway, matrix metalloproteinase-2, renin–angiotensin–aldosterone system, endothelin-1, cytokine genes, MTHFR and APO E variants. Fifteen-year survival data were obtained from the national insurance registry. All data were available in the case of 150 patients with 3VD. Statistical analysis used stepwise Cox regression with dominant, recessive, or additive mode of genetic expression. Involved variables included age, sex, BMI, blood pressure, diabetes, ejection fraction, left main stenosis, previously diagnosed coronary stenosis, myocardial infarction in personal history, and coronary bypass along with polymorphisms pre-selected by log-rank tests. Out of the 23 polymorphisms, four were included in the model construction. SNP in the IL-6 gene rs1800795 (−174 G/C) has been found to be a significant predictor of survival. This SNP was in a linkage disequilibrium with rs1800797 (−597 G/A) in the same gene (D′ = 1.0), which was also found to constitute a significant predictor of survival when rs1800795 was not included in the model construction. Age, increased BMI, diabetes, low EF, and left main stenosis were also significant predictors in all models. Age, increased BMI, diabetes, low ejection fraction, left main stenosis, and genetic variation in the IL-6 promoter were established as significant independent risk factors for the survival of patients with three-vessel disease.

26 August 2015 in Genes & Nutrition
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Journal Article
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JMJan Machal
Jan Machal
Jan NovakJan Novak
Jan Novak
RHRenata Hezova
Renata Hezova
FZFilip Zlamal
Filip Zlamal
AVAnna Vasku
Anna Vasku
JBJulie Bienertova-Vasku
Julie Bienertova-Vasku

16 November 2018 in Current Vascular Pharmacology
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JMJan Machal
Jan Machal
OHOta Hlinomaz
Ota Hlinomaz
Background: Various antiplatelet drugs are used following Acute Coronary Syndromes (ACS). Of them, adenosine diphosphate receptor P2Y12 inhibitors clopidogrel, prasugrel and ticagrelor are currently used for post-ACS long-term treatment. Although they act on the same receptor, they differ in pharmacodynamics and pharmacokinetics. Several enzymes and transporters involved in the metabolism of P2Y12 inhibitors show genetic variability with functional impact. This includes Pglycoprotein, carboxylesterase 1 and, most notably, CYP2C19 that is important in clopidogrel activation. Common gain-of-function or loss-of-function alleles of CYP2C19 gene are associated with lower or higher platelet reactivity that may impact clinical outcomes of clopidogrel treatment. Prasugrel is considered to be less dependent on CYP2C19 variability as it is also metabolized by other CYP450 isoforms. Some studies, however, showed the relevance of CYP2C19 variants for platelet reactivity during prasugrel treatment as well. Ticagrelor is metabolized mainly by CYP3A4, which does not show functionally relevant genetic variability. Its concentrations may be modified by the variants of Pglycoprotein gene ABCB1. While no substantial difference between the clinical efficacy of prasugrel and ticagrelor has been documented, both of them have been shown to be superior to clopidogrel in post-ACS treatment. This can be partially explained by lower variability at each step of their metabolism. It is probable that factors influencing the pharmacokinetics of both drugs, including genetic factors, may predict the clinical efficacy of antiplatelet treatment in personalized medicine. Conclusion: We summarize the pharmacokinetics and pharmacogenetics of P2Y12 inhibitors with respect to their clinical effects in post-myocardial infarction treatment.