Julia Kroepfl - Academia.edu (original) (raw)
Papers by Julia Kroepfl
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Http Dx Doi Org 10 1089 Scd 2012 0017, Jan 11, 2012
The validity and reliability of different turn points in normoxia and normobaric hypoxia have not... more The validity and reliability of different turn points in normoxia and normobaric hypoxia have not been investigated yet.
Journal of sports science & medicine, 2016
Despite described benefits of aerobic high-intensity interval exercise (HIIE), the acute response... more Despite described benefits of aerobic high-intensity interval exercise (HIIE), the acute responses during different HIIE modes and associated health risks have only been sparsely discovered in heart disease patients. Therefore, the aim of this study was to investigate the acute responses for physiological parameters, cardiovascular and inflammatory biomarkers, and catecholamines yielded by two different aerobic HIIE protocols compared to continuous exercise (CE) in phase III cardiac rehabilitation. Eight cardiac patients (7 with coronary heart disease, 1 with myocarditis; 7 males, 1 female; age: 63.0 ± 9.4 years; height: 1.74 ± 0.05 m; weight: 83.6 ± 8.7 kg), all but one treated with ß-blocking agents, performed a maximal symptom-limited incremental exercise test (IET) and three different exercise tests matched for mean load (Pmean) and total duration: 1) short HIIE with a peak workload duration (tpeak) of 20 s and a peak workload (Ppeak) equal to the maximum power output (Pmax) fro...
Journal of Sports Science Medicine, Sep 29, 2014
The acute physiological processes during "aerobic" highintensity interval exercise (HIIE) and the... more The acute physiological processes during "aerobic" highintensity interval exercise (HIIE) and their regulation are inadequately studied. The main goal of this study was to investigate the acute metabolic and cardiorespiratory response to long and short HIIE compared to continuous exercise (CE) as well as its regulation and predictability. Six healthy well-trained sport students (5 males, 1 female; age: 25.7 ± 3.1 years; height: 1.80 ± 0.04 m; weight: 76.7 ± 6.4 kg; VO 2max : 4.33 ± 0.7 l·min -1 ) performed a maximal incremental exercise test (IET) and subsequently three different exercise sessions matched for mean load (P mean ) and exercise duration (28 min): 1) long HIIE with submaximal peak workloads (P peak = power output at 95 % of maximum heart rate), peak workload durations (t peak ) of 4 min, and recovery durations (t rec ) of 3 min, 2) short HIIE with P peak according to the maximum power output (P max ) from IET, t peak of 20 s, and individually calculated t rec (26.7 ± 13.4 s), and 3) CE with a target workload (P target ) equating to P mean of HIIE. In short HIIE, mean lactate (La mean ) (5.22 ± 1.41 mmol·l -1 ), peak La (7.14 ± 2.48 mmol·l -1 ), and peak heart rate (HR peak ) (181.00 ± 6.66 b·min -1 ) were significantly lower compared to long HIIE (La mean : 9.83 ± 2.78 mmol·l -1 ; La peak : 12.37 ± 4.17 mmol·l -1 , HR peak : 187.67 ± 5.72 b·min -1 ). No significant differences in any parameters were found between short HIIE and CE despite considerably higher peak workloads in short HIIE. The acute metabolic and peak cardiorespiratory demand during "aerobic" short HIIE was significantly lower compared to long HIIE and regulable via P mean . Consequently, short HIIE allows a consciously aimed triggering of specific and desired or required acute physiological responses.
The acute physiological processes during "aerobic" highintensity interval exercise (HIIE) and the... more The acute physiological processes during "aerobic" highintensity interval exercise (HIIE) and their regulation are inadequately studied. The main goal of this study was to investigate the acute metabolic and cardiorespiratory response to long and short HIIE compared to continuous exercise (CE) as well as its regulation and predictability. Six healthy well-trained sport students (5 males, 1 female; age: 25.7 ± 3.1 years; height: 1.80 ± 0.04 m; weight: 76.7 ± 6.4 kg; VO 2max : 4.33 ± 0.7 l·min -1 ) performed a maximal incremental exercise test (IET) and subsequently three different exercise sessions matched for mean load (P mean ) and exercise duration (28 min): 1) long HIIE with submaximal peak workloads (P peak = power output at 95 % of maximum heart rate), peak workload durations (t peak ) of 4 min, and recovery durations (t rec ) of 3 min, 2) short HIIE with P peak according to the maximum power output (P max ) from IET, t peak of 20 s, and individually calculated t rec (26.7 ± 13.4 s), and 3) CE with a target workload (P target ) equating to P mean of HIIE. In short HIIE, mean lactate (La mean ) (5.22 ± 1.41 mmol·l -1 ), peak La (7.14 ± 2.48 mmol·l -1 ), and peak heart rate (HR peak ) (181.00 ± 6.66 b·min -1 ) were significantly lower compared to long HIIE (La mean : 9.83 ± 2.78 mmol·l -1 ; La peak : 12.37 ± 4.17 mmol·l -1 , HR peak : 187.67 ± 5.72 b·min -1 ). No significant differences in any parameters were found between short HIIE and CE despite considerably higher peak workloads in short HIIE. The acute metabolic and peak cardiorespiratory demand during "aerobic" short HIIE was significantly lower compared to long HIIE and regulable via P mean . Consequently, short HIIE allows a consciously aimed triggering of specific and desired or required acute physiological responses.
Pattern Recognition Letters, 2008
Anal intraepithelial neoplasia (AIN) is a precancerous condition of growing concern, due to the s... more Anal intraepithelial neoplasia (AIN) is a precancerous condition of growing concern, due to the strong interrelation of AIN with infections caused by human papillomaviruses (HPV) and HIV. Several HPV-subtypes induce a variety of tumorous skin lesions and cause different stages of dysplasia and even cancer. The histological classification of AIN is becoming more and more important in clinical practice, due to increasing HPV infection rates throughout human population. Histological slices of anal tissues are commonly classified by individual inspections with all the unavoidable differences of the training status and variances of the individual.
Journal of sports science & medicine, 2015
The acute physiological processes during "aerobic" high-intensity interval exercise (HI... more The acute physiological processes during "aerobic" high-intensity interval exercise (HIIE) and their regulation are inadequately studied. The main goal of this study was to investigate the acute metabolic and cardiorespiratory response to long and short HIIE compared to continuous exercise (CE) as well as its regulation and predictability. Six healthy well-trained sport students (5 males, 1 female; age: 25.7 ± 3.1 years; height: 1.80 ± 0.04 m; weight: 76.7 ± 6.4 kg; VO2max: 4.33 ± 0.7 l·min(-1)) performed a maximal incremental exercise test (IET) and subsequently three different exercise sessions matched for mean load (Pmean) and exercise duration (28 min): 1) long HIIE with submaximal peak workloads (Ppeak = power output at 95 % of maximum heart rate), peak workload durations (tpeak) of 4 min, and recovery durations (trec) of 3 min, 2) short HIIE with Ppeak according to the maximum power output (Pmax) from IET, tpeak of 20 s, and individually calculated trec (26.7 ± 13.4 ...
Journal of sports science & medicine, 2014
The goal of this study is to evaluate the response of physiological variables to acute normobaric... more The goal of this study is to evaluate the response of physiological variables to acute normobaric hypoxia compared to normoxia and its influence on the lactate turn point determination according to the three-phase model of energy supply (Phase I: metabolically balanced at muscular level; Phase II: metabolically balanced at systemic level; Phase III: not metabolically balanced) during maximal incremental exercise. Ten physically active (VO2max 3.9 [0.49] l·min(-1)), healthy men (mean age [SD]: 25.3 [4.6] yrs.), participated in the study. All participants performed two maximal cycle ergometric exercise tests under normoxic as well as hypoxic conditions (FiO2 = 14%). Blood lactate concentration, heart rate, gas exchange data, and power output at maximum and the first and the second lactate turn point (LTP1, LTP2), the heart rate turn point (HRTP) and the first and the second ventilatory turn point (VETP1, VETP2) were determined. Since in normobaric hypoxia absolute power output (P) was...
PLoS ONE, 2014
A recent study showed that ergometry increased circulating hematopoietic stem and progenitor cell... more A recent study showed that ergometry increased circulating hematopoietic stem and progenitor cell (CPC) numbers, but reduced hematopoietic colony forming capacity/functionality under normoxia and normobaric hypoxia. Herein we investigated whether an exercise-induced elevated plasma free/bound norepinephrine (NE) concentration could be responsible for directly influencing CPC functionality. Venous blood was taken from ten healthy male subjects (25.3+/24.4 yrs) before and 4 times after ergometry under normoxia and normobaric hypoxia (F i O 2 ,0.15). The circulating hematopoietic stem and progenitor cell numbers were correlated with free/bound NE, free/bound epinephrine (EPI), cortisol (Co) and interleukin-6 (IL-6). Additionally, the influence of exercise-induced NE and blood lactate (La) on CPC functionality was analyzed in a randomly selected group of subjects (n = 6) in vitro under normoxia by secondary colony-forming unit granulocyte macrophage assays. Concentrations of free NE, EPI, Co and IL-6 were significantly increased post-exercise under normoxia/hypoxia. Ergometry-induced free NE concentrations found in vivo showed a significant impairment of CPC functionality in vitro under normoxia. Thus, ergometry-induced free NE was thought to trigger CPC mobilization 10 minutes post-exercise, but as previously shown impairs CPC proliferative capacity/functionality at the same time. The obtained results suggest that an ergometry-induced free NE concentration has a direct negative effect on CPC functionality. Cortisol may further influence CPC dynamics and functionality.
Although amateur sports have become increasingly competitive within recent decades, there are as ... more Although amateur sports have become increasingly competitive within recent decades, there are as yet few studies on the possible health risks for athletes. This study aims to determine the impact of ultra-endurance exerciseinduced stress on the number and function of circulating hematopoietic progenitor cells (CPCs) and hematological, inflammatory, clinical, metabolic, and stress parameters in moderately trained amateur athletes. Following ultraendurance exercise, there were significant increases in leukocytes, platelets, interleukin-6, fibrinogen, tissue enzymes, blood lactate, serum cortisol, and matrix metalloproteinase-9. Ultra-endurance exercise did not influence the number of CPCs but resulted in a highly significant decline of CPC functionality after the competition. Furthermore, Epstein-Barr virus was seen to be reactivated in one of seven athletes. The link between exercise-induced stress and decline of CPC functionality is supported by a negative correlation between cortisol and CPC function. We conclude that ultra-endurance exercise induces metabolic stress and an inflammatory response that affects not only mature hematopoietic cells but also the function of the immature hematopoietic stem and progenitor cell fraction, which make up the immune system and provide for regeneration.
Stem Cells and Development, 2012
Circulating hematopoietic progenitor cells (CPCs) may be triggered by physical exercise and/or no... more Circulating hematopoietic progenitor cells (CPCs) may be triggered by physical exercise and/or normobaric hypoxia from the bone marrow. The aim of the study was to investigate the influence of physical exercise and normobaric hypoxia on CPC number and functionality in the peripheral blood as well as the involvement of oxidative stress parameters as possibly active agents. Ten healthy male subjects (25.3±4.4 years) underwent a standardized cycle incremental exercise test protocol (40 W+20 W/min) under either normoxic (FiO2 ∼0.21) or hypoxic conditions (FiO2<0.15, equals 3,500 m, 3 h xposure) within a time span of at least 1 week. Blood was drawn from the cubital vein before and 10, 30, 60, and 120 min after exercise. The number of CPCs in the peripheral blood was analyzed by flow cytometry (CD34/CD45-positive cells). The functionality of cells present was addressed by secondary colony-forming unit-granulocyte macrophage (CFU-GM) assays. To determine a possible correlation between the mobilization of CPCs and reactive oxygen species, parameters for oxidative stress such as malondialdehyde (MDA) and myeloperoxidase (MPO) were obtained. Data showed a significant increase of CPC release under normoxic as well as hypoxic conditions after 10 min of recovery (P<0.01). Most interestingly, although CD34+/CD45dim cells increased in number, the proliferative capacity of CPCs decreased significantly 10 min after cessation of exercise (P<0.05). A positive correlation between CPCs and MDA/MPO levels turned out to be significant for both normoxic and hypoxic conditions (P<0.05/P<0.01). Hypoxia did not provoke an additional effect. Although the CPC frequency increased, the functionality of CPCs decreased significantly after exercise, possibly due to the influence of increased oxidative stress levels.
Medicine & Science in Sports & Exercise, 2010
Chaos, Solitons & Fractals, 2011
It is well known that human papillomaviruses (HPV) induce a variety of tumorous lesions of the sk... more It is well known that human papillomaviruses (HPV) induce a variety of tumorous lesions of the skin. HPV-subtypes also cause premalignant lesions which are termed anal intraepithelial neoplasia (AIN). The clinical classification of AIN is of growing interest in clinical practice, due to increasing HPV infection rates throughout human population. The common classification approach is based on subjective inspections of histological slices of anal tissues with all the drawbacks of depending on the status and individual variances of the trained pathologists.
British Journal of Sports Medicine, 2013
Very low body mass, extreme mass changes, and extremely low per cent body fat are becoming increa... more Very low body mass, extreme mass changes, and extremely low per cent body fat are becoming increasingly common in many sports, but sufficiently reliable and accurate field methods for body composition assessment in athletes are missing. Nineteen female athletes were investigated (mean (SD) age: 19.5 (± 3.3) years; body mass: 59.6 (± 7.6) kg; height: 1.674 (± 0.056) m; BMI: 21.3 (± 2.3) kg/m(2)). Three observers applied diagnostic B-mode-ultrasound (US) combined with the evaluation software for subcutaneous adipose tissue measurements at eight ISAK sites (International Society for the Advancement of Kinanthrometry). Regression and reliability analyses are presented. US measurements and evaluation of subcutaneous adipose tissue (SAT) thicknesses (including fibrous structures: D(included); n=378) resulted in an SE of estimate SEE=0.60 mm, R(2)=0.98 (p<0.001), limit of agreement LOA=1.18, ICC=0.968 (0.957-0.977). Similar values were found for D(excluded): SEE=0.68 mm, R(2)=0.97 (p<0.001). D(included) at individual ISAK sites: at biceps, R(2)=0.87 and intraclass-correlation coefficient ICC=0.811 were lowest and SEE=0.79 mm was highest. Values at all other sites ranged from R(2): 0.94-0.99, SEE: 0.42-0.65 mm, and ICC: 0.917-0.985. Interobserver coefficients ranged from 0.92 to 0.99, except for biceps (0.74, 0.83 and 0.87). Evaluations of 20 randomly selected US images by three observers (D(included)) resulted in: SEE=0.15 mm, R(2)=0.998(p<0.001), ICC=0.997 (0.993, 0999). Subject to optimal choice of sites and certain standardisations, US can offer a highly reliable field method for measurement of uncompressed thickness of the SAT. High accuracy and high reliability of measurement, as obtained with this US approach, are essential for protection of the athlete's health and also for optimising performance.
British Journal of Sports Medicine, 2013
Extremely low weight and rapid changes in weight and body composition have become major concerns ... more Extremely low weight and rapid changes in weight and body composition have become major concerns in many sports, but sufficiently accurate field methods for body composition assessment in athletes are missing. This study aimed to explore the use of ultrasound methods for assessment of body fat content in athletes. 19 female athletes (stature: 1.67(± 0.06) m, weight: 59.6(± 7.6) kg; age: 19.5(± 3.3) years) were investigated by three observers using a novel ultrasound method for thickness measurement of uncompressed subcutaneous adipose tissue and of embedded structures. Two observers also measured skinfold thickness at eight International Society for the Advancement of Kinanthrometry (ISAK) sites; mean skinfold values were compared to mean subcutaneous adipose tissue thicknesses measured by ultrasound. Interobserver reliability of imaging and evaluation obtained by this ultrasound technique: intraclass correlation coefficient ICC=0.968 (95% CI 0.957 to 0.977); evaluation of given images: ICC=0.997 (0.993 to 0.999). Skinfold compared to ultrasound thickness showed that compressibility of subcutaneous adipose tissue depends largely on the site and the person: regression slopes ranged from 0.61 (biceps) to 1.59 (thigh) and CIs were large. Limits of agreement ranged from 2.6 to 8.6 mm. Regression lines did not intercept the skinfold axis at zero because of the skin thickness being included in the skinfold. The four ISAK trunk sites caused ultrasound imaging problems in 13 of 152 sites (8 ISAK sites, 19 athletes). The ultrasound method allows measurement of uncompressed subcutaneous adipose tissue thickness with an accuracy of 0.1-0.5 mm, depending on the probe frequency. Compressibility of the skinfold depends on the anatomical site, and skin thickness varies by a factor of two. This inevitably limits the skinfold methods for body fat estimation. Ultrasound accuracy for subcutaneous adipose tissue measurement is limited by the plasticity of fat and furrowed tissue borders. Comparative US measurements show that skinfold measurements do not allow accurate assessment of subcutaneous adipose tissue thickness.
Histochemistry and Cell Biology, 2013
The aim of the present study was to evaluate the potential of intraoral harvested alveolar bone a... more The aim of the present study was to evaluate the potential of intraoral harvested alveolar bone as an alternative source of multipotent mesenchymal stromal cells for future applications in oral and maxillofacial tissue engineering. Explant cultures were established from 20 alveolar bone samples harvested from the oblique line immediately before wisdom tooth removal. Morphology and proliferation characteristics of the in vitro expanded cells, referred to as human alveolar bone-derived cells (hABDCs), were studied using phase-contrast microscopy. Immunocytochemical analysis of their surface marker expression was conducted using monoclonal antibodies defining mesenchymal stromal cells. To evaluate their multilineage differentiation potential, hABDCs were induced to differentiate along the osteogenic, adipogenic, and chondrogenic lineage and compared to bone marrow mesenchymal stromal cells (hBMSCs) on mRNA and protein levels applying RT-PCR and cytochemical staining methods. hABDCs showed typical morphological characteristics comparable to those of hBMSCs such as being mononuclear, fibroblast-like, spindle-shaped, and plastic adherent. Immunophenotypically, cells were positive for CD105, CD90, and CD73 while negative for CD45, CD34, CD14, CD79α, and HLA-DR surface molecules, indicating an antigen expression pattern considered typical for multipotent mesenchymal stromal cells. As evidenced by RT-PCR and cytochemistry, hABDCs showed multilineage differentiation and similar chondrogenic and osteogenic differentiation potentials when compared to hBMSCs. Our findings demonstrate that human alveolar bone contains mesenchymal progenitor cells that can be isolated and expanded in vitro and are capable of trilineage differentiation, providing a reservoir of multipotent mesenchymal cells from an easily accessible tissue source.
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Http Dx Doi Org 10 1089 Scd 2012 0017, Jan 11, 2012
The validity and reliability of different turn points in normoxia and normobaric hypoxia have not... more The validity and reliability of different turn points in normoxia and normobaric hypoxia have not been investigated yet.
Journal of sports science & medicine, 2016
Despite described benefits of aerobic high-intensity interval exercise (HIIE), the acute response... more Despite described benefits of aerobic high-intensity interval exercise (HIIE), the acute responses during different HIIE modes and associated health risks have only been sparsely discovered in heart disease patients. Therefore, the aim of this study was to investigate the acute responses for physiological parameters, cardiovascular and inflammatory biomarkers, and catecholamines yielded by two different aerobic HIIE protocols compared to continuous exercise (CE) in phase III cardiac rehabilitation. Eight cardiac patients (7 with coronary heart disease, 1 with myocarditis; 7 males, 1 female; age: 63.0 ± 9.4 years; height: 1.74 ± 0.05 m; weight: 83.6 ± 8.7 kg), all but one treated with ß-blocking agents, performed a maximal symptom-limited incremental exercise test (IET) and three different exercise tests matched for mean load (Pmean) and total duration: 1) short HIIE with a peak workload duration (tpeak) of 20 s and a peak workload (Ppeak) equal to the maximum power output (Pmax) fro...
Journal of Sports Science Medicine, Sep 29, 2014
The acute physiological processes during "aerobic" highintensity interval exercise (HIIE) and the... more The acute physiological processes during "aerobic" highintensity interval exercise (HIIE) and their regulation are inadequately studied. The main goal of this study was to investigate the acute metabolic and cardiorespiratory response to long and short HIIE compared to continuous exercise (CE) as well as its regulation and predictability. Six healthy well-trained sport students (5 males, 1 female; age: 25.7 ± 3.1 years; height: 1.80 ± 0.04 m; weight: 76.7 ± 6.4 kg; VO 2max : 4.33 ± 0.7 l·min -1 ) performed a maximal incremental exercise test (IET) and subsequently three different exercise sessions matched for mean load (P mean ) and exercise duration (28 min): 1) long HIIE with submaximal peak workloads (P peak = power output at 95 % of maximum heart rate), peak workload durations (t peak ) of 4 min, and recovery durations (t rec ) of 3 min, 2) short HIIE with P peak according to the maximum power output (P max ) from IET, t peak of 20 s, and individually calculated t rec (26.7 ± 13.4 s), and 3) CE with a target workload (P target ) equating to P mean of HIIE. In short HIIE, mean lactate (La mean ) (5.22 ± 1.41 mmol·l -1 ), peak La (7.14 ± 2.48 mmol·l -1 ), and peak heart rate (HR peak ) (181.00 ± 6.66 b·min -1 ) were significantly lower compared to long HIIE (La mean : 9.83 ± 2.78 mmol·l -1 ; La peak : 12.37 ± 4.17 mmol·l -1 , HR peak : 187.67 ± 5.72 b·min -1 ). No significant differences in any parameters were found between short HIIE and CE despite considerably higher peak workloads in short HIIE. The acute metabolic and peak cardiorespiratory demand during "aerobic" short HIIE was significantly lower compared to long HIIE and regulable via P mean . Consequently, short HIIE allows a consciously aimed triggering of specific and desired or required acute physiological responses.
The acute physiological processes during "aerobic" highintensity interval exercise (HIIE) and the... more The acute physiological processes during "aerobic" highintensity interval exercise (HIIE) and their regulation are inadequately studied. The main goal of this study was to investigate the acute metabolic and cardiorespiratory response to long and short HIIE compared to continuous exercise (CE) as well as its regulation and predictability. Six healthy well-trained sport students (5 males, 1 female; age: 25.7 ± 3.1 years; height: 1.80 ± 0.04 m; weight: 76.7 ± 6.4 kg; VO 2max : 4.33 ± 0.7 l·min -1 ) performed a maximal incremental exercise test (IET) and subsequently three different exercise sessions matched for mean load (P mean ) and exercise duration (28 min): 1) long HIIE with submaximal peak workloads (P peak = power output at 95 % of maximum heart rate), peak workload durations (t peak ) of 4 min, and recovery durations (t rec ) of 3 min, 2) short HIIE with P peak according to the maximum power output (P max ) from IET, t peak of 20 s, and individually calculated t rec (26.7 ± 13.4 s), and 3) CE with a target workload (P target ) equating to P mean of HIIE. In short HIIE, mean lactate (La mean ) (5.22 ± 1.41 mmol·l -1 ), peak La (7.14 ± 2.48 mmol·l -1 ), and peak heart rate (HR peak ) (181.00 ± 6.66 b·min -1 ) were significantly lower compared to long HIIE (La mean : 9.83 ± 2.78 mmol·l -1 ; La peak : 12.37 ± 4.17 mmol·l -1 , HR peak : 187.67 ± 5.72 b·min -1 ). No significant differences in any parameters were found between short HIIE and CE despite considerably higher peak workloads in short HIIE. The acute metabolic and peak cardiorespiratory demand during "aerobic" short HIIE was significantly lower compared to long HIIE and regulable via P mean . Consequently, short HIIE allows a consciously aimed triggering of specific and desired or required acute physiological responses.
Pattern Recognition Letters, 2008
Anal intraepithelial neoplasia (AIN) is a precancerous condition of growing concern, due to the s... more Anal intraepithelial neoplasia (AIN) is a precancerous condition of growing concern, due to the strong interrelation of AIN with infections caused by human papillomaviruses (HPV) and HIV. Several HPV-subtypes induce a variety of tumorous skin lesions and cause different stages of dysplasia and even cancer. The histological classification of AIN is becoming more and more important in clinical practice, due to increasing HPV infection rates throughout human population. Histological slices of anal tissues are commonly classified by individual inspections with all the unavoidable differences of the training status and variances of the individual.
Journal of sports science & medicine, 2015
The acute physiological processes during "aerobic" high-intensity interval exercise (HI... more The acute physiological processes during "aerobic" high-intensity interval exercise (HIIE) and their regulation are inadequately studied. The main goal of this study was to investigate the acute metabolic and cardiorespiratory response to long and short HIIE compared to continuous exercise (CE) as well as its regulation and predictability. Six healthy well-trained sport students (5 males, 1 female; age: 25.7 ± 3.1 years; height: 1.80 ± 0.04 m; weight: 76.7 ± 6.4 kg; VO2max: 4.33 ± 0.7 l·min(-1)) performed a maximal incremental exercise test (IET) and subsequently three different exercise sessions matched for mean load (Pmean) and exercise duration (28 min): 1) long HIIE with submaximal peak workloads (Ppeak = power output at 95 % of maximum heart rate), peak workload durations (tpeak) of 4 min, and recovery durations (trec) of 3 min, 2) short HIIE with Ppeak according to the maximum power output (Pmax) from IET, tpeak of 20 s, and individually calculated trec (26.7 ± 13.4 ...
Journal of sports science & medicine, 2014
The goal of this study is to evaluate the response of physiological variables to acute normobaric... more The goal of this study is to evaluate the response of physiological variables to acute normobaric hypoxia compared to normoxia and its influence on the lactate turn point determination according to the three-phase model of energy supply (Phase I: metabolically balanced at muscular level; Phase II: metabolically balanced at systemic level; Phase III: not metabolically balanced) during maximal incremental exercise. Ten physically active (VO2max 3.9 [0.49] l·min(-1)), healthy men (mean age [SD]: 25.3 [4.6] yrs.), participated in the study. All participants performed two maximal cycle ergometric exercise tests under normoxic as well as hypoxic conditions (FiO2 = 14%). Blood lactate concentration, heart rate, gas exchange data, and power output at maximum and the first and the second lactate turn point (LTP1, LTP2), the heart rate turn point (HRTP) and the first and the second ventilatory turn point (VETP1, VETP2) were determined. Since in normobaric hypoxia absolute power output (P) was...
PLoS ONE, 2014
A recent study showed that ergometry increased circulating hematopoietic stem and progenitor cell... more A recent study showed that ergometry increased circulating hematopoietic stem and progenitor cell (CPC) numbers, but reduced hematopoietic colony forming capacity/functionality under normoxia and normobaric hypoxia. Herein we investigated whether an exercise-induced elevated plasma free/bound norepinephrine (NE) concentration could be responsible for directly influencing CPC functionality. Venous blood was taken from ten healthy male subjects (25.3+/24.4 yrs) before and 4 times after ergometry under normoxia and normobaric hypoxia (F i O 2 ,0.15). The circulating hematopoietic stem and progenitor cell numbers were correlated with free/bound NE, free/bound epinephrine (EPI), cortisol (Co) and interleukin-6 (IL-6). Additionally, the influence of exercise-induced NE and blood lactate (La) on CPC functionality was analyzed in a randomly selected group of subjects (n = 6) in vitro under normoxia by secondary colony-forming unit granulocyte macrophage assays. Concentrations of free NE, EPI, Co and IL-6 were significantly increased post-exercise under normoxia/hypoxia. Ergometry-induced free NE concentrations found in vivo showed a significant impairment of CPC functionality in vitro under normoxia. Thus, ergometry-induced free NE was thought to trigger CPC mobilization 10 minutes post-exercise, but as previously shown impairs CPC proliferative capacity/functionality at the same time. The obtained results suggest that an ergometry-induced free NE concentration has a direct negative effect on CPC functionality. Cortisol may further influence CPC dynamics and functionality.
Although amateur sports have become increasingly competitive within recent decades, there are as ... more Although amateur sports have become increasingly competitive within recent decades, there are as yet few studies on the possible health risks for athletes. This study aims to determine the impact of ultra-endurance exerciseinduced stress on the number and function of circulating hematopoietic progenitor cells (CPCs) and hematological, inflammatory, clinical, metabolic, and stress parameters in moderately trained amateur athletes. Following ultraendurance exercise, there were significant increases in leukocytes, platelets, interleukin-6, fibrinogen, tissue enzymes, blood lactate, serum cortisol, and matrix metalloproteinase-9. Ultra-endurance exercise did not influence the number of CPCs but resulted in a highly significant decline of CPC functionality after the competition. Furthermore, Epstein-Barr virus was seen to be reactivated in one of seven athletes. The link between exercise-induced stress and decline of CPC functionality is supported by a negative correlation between cortisol and CPC function. We conclude that ultra-endurance exercise induces metabolic stress and an inflammatory response that affects not only mature hematopoietic cells but also the function of the immature hematopoietic stem and progenitor cell fraction, which make up the immune system and provide for regeneration.
Stem Cells and Development, 2012
Circulating hematopoietic progenitor cells (CPCs) may be triggered by physical exercise and/or no... more Circulating hematopoietic progenitor cells (CPCs) may be triggered by physical exercise and/or normobaric hypoxia from the bone marrow. The aim of the study was to investigate the influence of physical exercise and normobaric hypoxia on CPC number and functionality in the peripheral blood as well as the involvement of oxidative stress parameters as possibly active agents. Ten healthy male subjects (25.3±4.4 years) underwent a standardized cycle incremental exercise test protocol (40 W+20 W/min) under either normoxic (FiO2 ∼0.21) or hypoxic conditions (FiO2<0.15, equals 3,500 m, 3 h xposure) within a time span of at least 1 week. Blood was drawn from the cubital vein before and 10, 30, 60, and 120 min after exercise. The number of CPCs in the peripheral blood was analyzed by flow cytometry (CD34/CD45-positive cells). The functionality of cells present was addressed by secondary colony-forming unit-granulocyte macrophage (CFU-GM) assays. To determine a possible correlation between the mobilization of CPCs and reactive oxygen species, parameters for oxidative stress such as malondialdehyde (MDA) and myeloperoxidase (MPO) were obtained. Data showed a significant increase of CPC release under normoxic as well as hypoxic conditions after 10 min of recovery (P<0.01). Most interestingly, although CD34+/CD45dim cells increased in number, the proliferative capacity of CPCs decreased significantly 10 min after cessation of exercise (P<0.05). A positive correlation between CPCs and MDA/MPO levels turned out to be significant for both normoxic and hypoxic conditions (P<0.05/P<0.01). Hypoxia did not provoke an additional effect. Although the CPC frequency increased, the functionality of CPCs decreased significantly after exercise, possibly due to the influence of increased oxidative stress levels.
Medicine & Science in Sports & Exercise, 2010
Chaos, Solitons & Fractals, 2011
It is well known that human papillomaviruses (HPV) induce a variety of tumorous lesions of the sk... more It is well known that human papillomaviruses (HPV) induce a variety of tumorous lesions of the skin. HPV-subtypes also cause premalignant lesions which are termed anal intraepithelial neoplasia (AIN). The clinical classification of AIN is of growing interest in clinical practice, due to increasing HPV infection rates throughout human population. The common classification approach is based on subjective inspections of histological slices of anal tissues with all the drawbacks of depending on the status and individual variances of the trained pathologists.
British Journal of Sports Medicine, 2013
Very low body mass, extreme mass changes, and extremely low per cent body fat are becoming increa... more Very low body mass, extreme mass changes, and extremely low per cent body fat are becoming increasingly common in many sports, but sufficiently reliable and accurate field methods for body composition assessment in athletes are missing. Nineteen female athletes were investigated (mean (SD) age: 19.5 (± 3.3) years; body mass: 59.6 (± 7.6) kg; height: 1.674 (± 0.056) m; BMI: 21.3 (± 2.3) kg/m(2)). Three observers applied diagnostic B-mode-ultrasound (US) combined with the evaluation software for subcutaneous adipose tissue measurements at eight ISAK sites (International Society for the Advancement of Kinanthrometry). Regression and reliability analyses are presented. US measurements and evaluation of subcutaneous adipose tissue (SAT) thicknesses (including fibrous structures: D(included); n=378) resulted in an SE of estimate SEE=0.60 mm, R(2)=0.98 (p<0.001), limit of agreement LOA=1.18, ICC=0.968 (0.957-0.977). Similar values were found for D(excluded): SEE=0.68 mm, R(2)=0.97 (p<0.001). D(included) at individual ISAK sites: at biceps, R(2)=0.87 and intraclass-correlation coefficient ICC=0.811 were lowest and SEE=0.79 mm was highest. Values at all other sites ranged from R(2): 0.94-0.99, SEE: 0.42-0.65 mm, and ICC: 0.917-0.985. Interobserver coefficients ranged from 0.92 to 0.99, except for biceps (0.74, 0.83 and 0.87). Evaluations of 20 randomly selected US images by three observers (D(included)) resulted in: SEE=0.15 mm, R(2)=0.998(p<0.001), ICC=0.997 (0.993, 0999). Subject to optimal choice of sites and certain standardisations, US can offer a highly reliable field method for measurement of uncompressed thickness of the SAT. High accuracy and high reliability of measurement, as obtained with this US approach, are essential for protection of the athlete's health and also for optimising performance.
British Journal of Sports Medicine, 2013
Extremely low weight and rapid changes in weight and body composition have become major concerns ... more Extremely low weight and rapid changes in weight and body composition have become major concerns in many sports, but sufficiently accurate field methods for body composition assessment in athletes are missing. This study aimed to explore the use of ultrasound methods for assessment of body fat content in athletes. 19 female athletes (stature: 1.67(± 0.06) m, weight: 59.6(± 7.6) kg; age: 19.5(± 3.3) years) were investigated by three observers using a novel ultrasound method for thickness measurement of uncompressed subcutaneous adipose tissue and of embedded structures. Two observers also measured skinfold thickness at eight International Society for the Advancement of Kinanthrometry (ISAK) sites; mean skinfold values were compared to mean subcutaneous adipose tissue thicknesses measured by ultrasound. Interobserver reliability of imaging and evaluation obtained by this ultrasound technique: intraclass correlation coefficient ICC=0.968 (95% CI 0.957 to 0.977); evaluation of given images: ICC=0.997 (0.993 to 0.999). Skinfold compared to ultrasound thickness showed that compressibility of subcutaneous adipose tissue depends largely on the site and the person: regression slopes ranged from 0.61 (biceps) to 1.59 (thigh) and CIs were large. Limits of agreement ranged from 2.6 to 8.6 mm. Regression lines did not intercept the skinfold axis at zero because of the skin thickness being included in the skinfold. The four ISAK trunk sites caused ultrasound imaging problems in 13 of 152 sites (8 ISAK sites, 19 athletes). The ultrasound method allows measurement of uncompressed subcutaneous adipose tissue thickness with an accuracy of 0.1-0.5 mm, depending on the probe frequency. Compressibility of the skinfold depends on the anatomical site, and skin thickness varies by a factor of two. This inevitably limits the skinfold methods for body fat estimation. Ultrasound accuracy for subcutaneous adipose tissue measurement is limited by the plasticity of fat and furrowed tissue borders. Comparative US measurements show that skinfold measurements do not allow accurate assessment of subcutaneous adipose tissue thickness.
Histochemistry and Cell Biology, 2013
The aim of the present study was to evaluate the potential of intraoral harvested alveolar bone a... more The aim of the present study was to evaluate the potential of intraoral harvested alveolar bone as an alternative source of multipotent mesenchymal stromal cells for future applications in oral and maxillofacial tissue engineering. Explant cultures were established from 20 alveolar bone samples harvested from the oblique line immediately before wisdom tooth removal. Morphology and proliferation characteristics of the in vitro expanded cells, referred to as human alveolar bone-derived cells (hABDCs), were studied using phase-contrast microscopy. Immunocytochemical analysis of their surface marker expression was conducted using monoclonal antibodies defining mesenchymal stromal cells. To evaluate their multilineage differentiation potential, hABDCs were induced to differentiate along the osteogenic, adipogenic, and chondrogenic lineage and compared to bone marrow mesenchymal stromal cells (hBMSCs) on mRNA and protein levels applying RT-PCR and cytochemical staining methods. hABDCs showed typical morphological characteristics comparable to those of hBMSCs such as being mononuclear, fibroblast-like, spindle-shaped, and plastic adherent. Immunophenotypically, cells were positive for CD105, CD90, and CD73 while negative for CD45, CD34, CD14, CD79α, and HLA-DR surface molecules, indicating an antigen expression pattern considered typical for multipotent mesenchymal stromal cells. As evidenced by RT-PCR and cytochemistry, hABDCs showed multilineage differentiation and similar chondrogenic and osteogenic differentiation potentials when compared to hBMSCs. Our findings demonstrate that human alveolar bone contains mesenchymal progenitor cells that can be isolated and expanded in vitro and are capable of trilineage differentiation, providing a reservoir of multipotent mesenchymal cells from an easily accessible tissue source.