المؤلفون: Juliane Hannemann, Julius Freytag, Lisa Maria Schiefer, Franziska Macholz, Mahdi Sareban, Lena Schmidt-Hutten, Heike Stang, Edzard Schwedhelm, Erik R. Swenson, Rainer Böger, Marc Moritz Berger

المصدر: Frontiers in Physiology, Vol 14 (2023)

مصطلحات موضوعية: nitric oxide, NO, ADMA (asymmetric dimethyl arginine), hypoxia, high altitude, biomarker, Physiology, QP1-981

الوصف: Introduction: High altitude exposure may lead to high altitude pulmonary hypertension (HAPH) and high altitude pulmonary edema (HAPE). The pathophysiologic processes of both entities have been linked to decreased nitric oxide (NO) availability.Methods: We studied the effect of acute high altitude exposure on the plasma concentrations of asymmetric (ADMA) and symmetric dimethylarginine (SDMA), L-arginine, L-ornithine, and L-citrulline in two independent studies. We further investigated whether these biomarkers involved in NO metabolism were related to HAPH and HAPE, respectively. Fifty (study A) and thirteen (study B) non-acclimatized lowlanders were exposed to 4,559 m for 44 and 67 h, respectively. In contrast to study A, the participants in study B were characterized by a history of at least one episode of HAPE. Arterial blood gases and biomarker concentrations in venous plasma were assessed at low altitude (baseline) and repeatedly at high altitude. HAPE was diagnosed by chest radiography, and HAPH by measuring right ventricular to atrial pressure gradient (RVPG) with transthoracic echocardiography. AMS was evaluated with the Lake Louise Score (LLS) and the AMS-C score.Results: In both studies SDMA concentration significantly increased at high altitude. ADMA baseline concentrations were higher in individuals with HAPE susceptibility (study B) compared to those without (study A). However, upon high altitude exposure ADMA only increased in individuals without HAPE susceptibility, while there was no further increase in those with HAPE susceptibility. We observed an acute and transient decrease of L-ornithine and a more delayed but prolonged reduction of L-citrulline during high altitude exposure. In both studies SDMA positively correlated and L-ornithine negatively correlated with RVPG. ADMA was significantly associated with the occurrence of HAPE (study B). ADMA and SDMA were inversely correlated with alveolar PO2, while L-ornithine was inversely correlated with blood oxygenation and haemoglobin levels, respectively.Discussion: In non-acclimatized individuals ADMA and SDMA, two biomarkers decreasing endothelial NO production, increased after acute exposure to 4,559 m. The observed biomarker changes suggest that both NO synthesis and arginase pathways are involved in the pathophysiology of HAPH and HAPE.

وصف الملف: electronic resource

العلاقة: https://www.frontiersin.org/articles/10.3389/fphys.2023.1297636/fullTest; https://doaj.org/toc/1664-042XTest

الوصول الحر: https://doaj.org/article/008c53bbff684ba4b609e62692ab92eeTest

المؤلفون: Heimo Mairbäurl, Christoph Dehnert, Franziska Macholz, Daniel Dankl, Mahdi Sareban, Marc M. Berger

المصدر: International Journal of Molecular Sciences, Vol 20, Iss 17, p 4105 (2019)

مصطلحات موضوعية: high-altitude pulmonary edema, acute mountain sickness, oxygen diffusion limitation, Biology (General), QH301-705.5, Chemistry, QD1-999

الوصف: Individuals ascending rapidly to altitudes >2500 m may develop symptoms of acute mountain sickness (AMS) within a few hours of arrival and/or high-altitude pulmonary edema (HAPE), which occurs typically during the first three days after reaching altitudes above 3000−3500 m. Both diseases have distinct pathologies, but both present with a pronounced decrease in oxygen saturation of hemoglobin in arterial blood (SO2). This raises the question of mechanisms impairing the diffusion of oxygen (O2) across the alveolar wall and whether the higher degree of hypoxemia is in causal relationship with developing the respective symptoms. In an attempt to answer these questions this article will review factors affecting alveolar gas diffusion, such as alveolar ventilation, the alveolar-to-arterial O2-gradient, and balance between filtration of fluid into the alveolar space and its clearance, and relate them to the respective disease. The resultant analysis reveals that in both AMS and HAPE the main pathophysiologic mechanisms are activated before aggravated decrease in SO2 occurs, indicating that impaired alveolar epithelial function and the resultant diffusion limitation for oxygen may rather be a consequence, not the primary cause, of these altitude-related illnesses.

وصف الملف: electronic resource

العلاقة: https://www.mdpi.com/1422-0067/20/17/4105Test; https://doaj.org/toc/1422-0067Test

الوصول الحر: https://doaj.org/article/a830a401959c44b99a57ca80b7b3a736Test

المؤلفون: Franziska Macholz, Mahdi Sareban, Peter Schmidt, Lisa M. Schiefer, Erik R. Swenson, Marc M. Berger, Heimo Mairbäurl, Kai E. Swenson

المصدر: High Altitude Medicine & Biology. 21:176-183

مصطلحات موضوعية: Adult, Physiology, Medizin, Vascular permeability, Altitude Sickness, 030204 cardiovascular system & hematology, Glycocalyx, Syndecan 1, Plasma, Young Adult, 03 medical and health sciences, chemistry.chemical_compound, 0302 clinical medicine, Altitude, Humans, skin and connective tissue diseases, ICAM-1, Chemistry, Public Health, Environmental and Occupational Health, 030229 sport sciences, General Medicine, Heparan sulfate, Middle Aged, Effects of high altitude on humans, Endothelial glycocalyx, Cell biology, Acute Disease, Endothelium, Vascular, sense organs

الوصف: Background: The stress of high altitude alters vascular permeability, which may be related to structural changes in the endothelial glycocalyx. We aimed to study these changes by measuring plasma c...

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7f894fb7446850a730d393fccf8424ceTest
https://doi.org/10.1089/ham.2019.0081Test

المؤلفون: Bernhard Reich, Peter Schmidt, Sebastian Fried, Marc M. Berger, Mahdi Sareban, Josef Niebauer, Franziska Macholz, Heimo Mairbäurl, Tabea Perz

المصدر: The International Journal of Cardiovascular Imaging

مصطلحات موضوعية: Adult, Male, medicine.medical_specialty, Time Factors, Contraction (grammar), Acclimatization, Hypertension, Pulmonary, Atrial Function, Right, Right atrial, Pulmonary hypertension, Afterload, Internal medicine, medicine.artery, medicine, Humans, Radiology, Nuclear Medicine and imaging, Low altitude, Original Paper, Ventricular function, business.industry, Altitude, Atrial function, Middle Aged, Effects of high altitude on humans, medicine.disease, Myocardial Contraction, Echocardiography, Doppler, Echocardiography, Pulmonary artery, Ventricular Function, Right, Cardiology, Female, Cardiology and Cardiovascular Medicine, business

الوصف: Purpose Ascent to high altitude increases right ventricular (RV) afterload and decreases myocardial energy supply. This study evaluates physiologic variables and comprehensive echocardiographic indices of RV and right atrial (RA) function following rapid ascent to high altitude. Methods Fifty healthy volunteers actively ascended from 1130 to 4559 m in Results sPAP increased from baseline (24 ± 4 mmHg) to the first altitude examination (39 ± 8 mmHg, p p = 0.07) secondary to a significant increase of RA contraction strain (19.2 ± 6.4 vs. 25.4 ± 9.6%, p Conclusion Active and rapid ascent of healthy individuals to 4559 m is associated with an increased contractile performance of the RA that compensates for the increased workload of the RV.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f1375e418dcde57278a4d4c393990511Test
https://doi.org/10.1007/s10554-020-01803-xTest

المؤلفون: Peter Schmidt, Larissa Schäfer, Quirin Zangl, Lisa M. Schiefer, Bernhard Reich, Barbara Mayr, Arnulf Hartl, Marc M. Berger, Josef Niebauer, Franciscus Inama, Gunnar Treff, Franziska Macholz, Mahdi Sareban, Peter Bärtsch

المصدر: Medicine & Science in Sports & Exercise. 52:1109-1115

مصطلحات موضوعية: Adult, Male, medicine.medical_specialty, Acclimatization, Physical Therapy, Sports Therapy and Rehabilitation, Hypoxic ventilatory response, Altitude Sickness, Young Adult, 03 medical and health sciences, 0302 clinical medicine, Altitude, Heart Rate, Parasympathetic Nervous System, Internal medicine, Heart rate, medicine, Humans, Heart rate variability, Orthopedics and Sports Medicine, Prospective Studies, biology, Athletes, business.industry, VO2 max, 030229 sport sciences, biology.organism_classification, Oxygen, Increased risk, Acute Disease, Basal metabolic rate, Physical Endurance, Cardiology, Basal Metabolism, Pulmonary Ventilation, business, Physical Conditioning, Human

الوصف: INTRODUCTION Acute mountain sickness (AMS) may develop in nonacclimatized individuals after exposure to altitudes ≥2500 m. Anecdotal reports suggest that endurance-trained (ET) athletes with a high maximal oxygen uptake (V˙O2max) may be at increased risk for AMS. Possible underlying mechanisms include a training-induced increase in resting parasympathetic activity, higher resting metabolic rate (RMR), and lower hypoxic ventilatory response (HVR). METHODS In 38 healthy, nonacclimatized men (19 ET and 19 untrained controls [UT], V˙O2max 66 ± 6 mL·min·kg vs 45 ± 7 mL·min·kg; P < 0.001) peripheral oxygen saturation (SpO2), heart rate variability, RMR, and poikilocapnic HVR were assessed at 424 m and during 48 h at 3450 m after passive ascent by train (~2 h). Acute mountain sickness was evaluated by AMS cerebral (AMS-C) score. RESULTS On day 1 at altitude, ET presented with a higher AMS incidence (42% vs 11%; P < 0.05) and severity (AMS-C score: ET, 0.48 ± 0.5 vs UT, 0.21 ± 0.2; P = 0.03), but no group difference was found on days 2 and 3. SpO2 decreased upon arrival at altitude (ET: 82% ± 6% vs UT: 83% ± 4%; ptime

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::faf5286bd1147d2992eede13b2bdcc95Test
https://doi.org/10.1249/mss.0000000000002232Test

المؤلفون: Larissa Schäfer, Marc M. Berger, Mahdi Sareban, Franziska Macholz, Lisa M. Schiefer, Peter Schmidt

المصدر: Notfall + Rettungsmedizin. 23:270-275

مصطلحات موضوعية: Gynecology, medicine.medical_specialty, Chemistry, Emergency Medicine, medicine

الوصف: Zusammenfassung Notfallmedikamente kommen an nahezu allen Orten dieser Erde zum Einsatz. Damit werden sie unterschiedlichsten Umweltbedingungen (Kälte, Hitze, direkte Sonneneinstrahlung) ausgesetzt. Sämtliche Daten zur Pharmakokinetik, Pharmakodynamik, Medikamentensicherheit und -haltbarkeit werden jedoch unter standardisierten Bedingungen erhoben, die sich von den Anwendungsbedingungen in der Notfallmedizin erheblich unterscheiden können. Durch die Kälte bei Wintereinsätzen im Gebirge können ebenso wie bei Einsätzen in großer Hitze und bei direkter Sonnenexposition chemische Reaktionen entstehen, welche die Eigenschaften der Medikamente bis hin zur kompletten Wirkungslosigkeit verändern können. Zusätzlich können Unterkühlung oder Überhitzung des Patienten zu einer Zentralisation bzw. Vasodilatation führen und damit das pharmakologische Verteilungsvolumen erheblich verändern, woraus Unter- bzw. Überdosierungen resultieren können. Gleichzeitig kann durch einen temperaturbedingt veränderten Metabolismus die Konjugation und Elimination von Medikamenten beeinflusst sein und zu einer unvorhersehbaren Verlängerung der Medikamentenwirkung führen. Trotz der erheblichen klinischen Relevanz dieser Thematik existieren bisher kaum Daten zu den konkreten Effekten extremer Umweltbedingungen auf die pharmakologischen Eigenschaften von Notfallmedikamenten. Diese Übersicht soll dazu dienen, den aktuellen Kenntnisstand der notfallmedizinischen Pharmakotherapie unter Extrembedingungen darzustellen.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::fc933828cbddc5fa1f9d620f287f57bcTest
https://doi.org/10.1007/s10049-019-00646-xTest

المؤلفون: Heimo Mairbäurl, Josef Niebauer, Peter Schmidt, Franziska Macholz, Marc M. Berger, Sebastian Fried, Tabea Perz, Bernhard Reich, Mahdi Sareban

المصدر: Scandinavian Journal of Medicine & Science in Sports

مصطلحات موضوعية: Adult, Male, Diastole, Physical Therapy, Sports Therapy and Rehabilitation, Speckle tracking echocardiography, 030204 cardiovascular system & hematology, Ventricular Function, Left, cardiac imaging, 030218 nuclear medicine & medical imaging, Ventricular Dysfunction, Left, 03 medical and health sciences, 0302 clinical medicine, Heart Rate, Administration, Inhalation, High-altitude pulmonary edema, Heart rate, medicine, Humans, Orthopedics and Sports Medicine, Heart Atria, Budesonide, speckle tracking echocardiography, Randomized Controlled Trials as Topic, hypoxia, business.industry, Altitude, Stroke Volume, Original Articles, Stroke volume, Mechanics, Middle Aged, Hypoxia (medical), Effects of high altitude on humans, Atrial Function, medicine.disease, Mountaineering, Preload, Echocardiography, Original Article, high altitude pulmonary edema, medicine.symptom, business

الوصف: Hypoxia challenges left ventricular (LV) function due to reduced energy supply. Conflicting results exist whether high‐altitude exposure impairs LV diastolic function and thus contributes to the high altitude‐induced increase in systolic pulmonary artery pressure (sPAP) and reduction in stroke volume (SV). This study aimed to assess LV diastolic function, LV end‐diastolic pressure (LVEDP), and LA mechanics using comprehensive echocardiographic imaging in healthy volunteers at 4559 m. Fifty subjects performed rapid (

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::dcc996cefbbb0a543f8422efbc67aab3Test
https://doi.org/10.1111/sms.13325Test

المؤلفون: Marc M. Berger, Daniel Dankl, Mahdi Sareban, Heimo Mairbäurl, Franziska Macholz, Christoph Dehnert

المصدر: International Journal of Molecular Sciences
International Journal of Molecular Sciences, Vol 20, Iss 17, p 4105 (2019)

مصطلحات موضوعية: medicine.medical_specialty, high-altitude pulmonary edema, Hypertension, Pulmonary, Review, 030204 cardiovascular system & hematology, Altitude Sickness, Catalysis, Hypoxemia, Inorganic Chemistry, lcsh:Chemistry, Diffusion, 03 medical and health sciences, 0302 clinical medicine, Internal medicine, High-altitude pulmonary edema, Medicine, Animals, Humans, Physical and Theoretical Chemistry, Hypoxia, Molecular Biology, lcsh:QH301-705.5, Spectroscopy, oxygen diffusion limitation, Oxygen saturation (medicine), Alveolar Wall, business.industry, Altitude, Organic Chemistry, General Medicine, Effects of high altitude on humans, Pulmonary edema, medicine.disease, Computer Science Applications, Oxygen, Pulmonary Alveoli, 030228 respiratory system, lcsh:Biology (General), lcsh:QD1-999, Vasoconstriction, Acute Disease, acute mountain sickness, Cardiology, Arterial blood, Hemoglobin, Disease Susceptibility, medicine.symptom, business

الوصف: Individuals ascending rapidly to altitudes >2500 m may develop symptoms of acute mountain sickness (AMS) within a few hours of arrival and/or high-altitude pulmonary edema (HAPE), which occurs typically during the first three days after reaching altitudes above 3000−3500 m. Both diseases have distinct pathologies, but both present with a pronounced decrease in oxygen saturation of hemoglobin in arterial blood (SO2). This raises the question of mechanisms impairing the diffusion of oxygen (O2) across the alveolar wall and whether the higher degree of hypoxemia is in causal relationship with developing the respective symptoms. In an attempt to answer these questions this article will review factors affecting alveolar gas diffusion, such as alveolar ventilation, the alveolar-to-arterial O2-gradient, and balance between filtration of fluid into the alveolar space and its clearance, and relate them to the respective disease. The resultant analysis reveals that in both AMS and HAPE the main pathophysiologic mechanisms are activated before aggravated decrease in SO2 occurs, indicating that impaired alveolar epithelial function and the resultant diffusion limitation for oxygen may rather be a consequence, not the primary cause, of these altitude-related illnesses.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::bf6fe8b0228392b969f6a47759562341Test
https://pubmed.ncbi.nlm.nih.gov/31443549Test

المؤلفون: Franziska Macholz, Ragnar Huhn, Marc M. Berger, Peter Schmidt

المصدر: AINS - Anästhesiologie · Intensivmedizin · Notfallmedizin · Schmerztherapie. 51:372-377

مصطلحات موضوعية: Hyperoxia, Gynecology, medicine.medical_specialty, Resuscitation, Anesthesiology and Pain Medicine, business.industry, Emergency Medicine, medicine, General Medicine, medicine.symptom, Critical Care and Intensive Care Medicine, business

الوصف: Uber Jahrzehnte gehorte Sauerstoff zur Standardtherapie zahlreicher akuter Krankheitsbilder, wie z.B. des akuten Myokardinfarkts. Im Bereich der perioperativen Medizin wird die Routine-Gabe hoher Sauerstoffkonzentrationen (>80%) u. a. zur Reduktion chirurgischer Wundinfektionen propagiert. Sauerstoff fuhrt jedoch zum Anstieg des systemvaskularen Widerstands, zur Reduktion der Herzfrequenz sowie des kardialen Schlagvolumens und somit zur Reduktion der mikrovaskularen Perfusion, z.B. in den Koronar- und Hirngefasen. Ergebnisse aus prospektiven, randomisierten und verblindeten Studien zu den Outcome-Effekten einer Hyperoxie in den Bereichen der Anasthesie und Intensivmedizin sind kaum vorhanden. Insbesondere jungere Daten weisen jedoch darauf hin, dass Hyperoxie zur Erhohung der perioperativen und intensivmedizinischen Morbiditat und Mortalitat fuhren konnte. Auch in den Leitlinien des European Resuscitation Councils von 2015 wird die Gabe von Sauerstoff bei verschiedenen Krankheitsbildern kritisch bewertet. Der vorliegende Artikel soll eine orientierende Ubersicht zu den physiologischen und klinischen Effekten einer Hyperoxie geben und ihre Anwendung im perioperativen Bereich sowie in der Intensivmedizin beleuchten.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::9ff044996de2bab6accadf88de5f5b11Test
https://doi.org/10.1055/s-0041-105156Test

المؤلفون: Gunnar Treff, Franziska Macholz, Jürgen M. Steinacker, Lisa M. Schiefer, Larissa Schäfer, Marc M. Berger, Mahdi Sareban

المصدر: Medicine & Science in Sports & Exercise. 52:778-778

مصطلحات موضوعية: medicine.medical_specialty, business.industry, Internal medicine, medicine, Cardiology, Physical Therapy, Sports Therapy and Rehabilitation, Orthopedics and Sports Medicine, Hypoxia (medical), medicine.symptom, business

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::35b9693b6720807230e163741e35a960Test
https://doi.org/10.1249/01.mss.0000683688.16187.b6Test