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  1. Article ; Online: A pipeline for the development and analysis of extracellular vesicle-based transcriptomic biomarkers in molecular diagnostics.

    Grätz, Christian / Schuster, Martina / Brandes, Florian / Meidert, Agnes S / Kirchner, Benedikt / Reithmair, Marlene / Schelling, Gustav / Pfaffl, Michael W

    Molecular aspects of medicine

    2024  Volume 97, Page(s) 101269

    Abstract: Extracellular vesicles are shed by every cell type and can be found in any biofluid. They contain different molecules that can be utilized as biomarkers, including several RNA species which they protect from degradation. Here, we present a pipeline for ... ...

    Abstract Extracellular vesicles are shed by every cell type and can be found in any biofluid. They contain different molecules that can be utilized as biomarkers, including several RNA species which they protect from degradation. Here, we present a pipeline for the development and analysis of extracellular vesicle-associated transcriptomic biomarkers that our group has successfully applied multiple times. We highlight the key steps of the pipeline and give particular emphasis to the necessary quality control checkpoints, which are linked to numerous available guidelines that should be considered along the workflow. Our pipeline starts with patient recruitment and continues with blood sampling and processing. The purification and characterization of extracellular vesicles is explained in detail, as well as the isolation and quality control of extracellular vesicle-associated RNA. We point out the possible pitfalls during library preparation and RNA sequencing and present multiple bioinformatic tools to pinpoint biomarker signature candidates from the sequencing data. Finally, considerations and pitfalls during the validation of the biomarker signature using RT-qPCR will be elaborated.
    Language English
    Publishing date 2024-03-28
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 197640-0
    ISSN 1872-9452 ; 0098-2997
    ISSN (online) 1872-9452
    ISSN 0098-2997
    DOI 10.1016/j.mam.2024.101269
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Techniques for Non-Invasive Monitoring of Arterial Blood Pressure.

    Meidert, Agnes S / Saugel, Bernd

    Frontiers in medicine

    2018  Volume 4, Page(s) 231

    Abstract: Since both, hypotension and hypertension, can potentially impair the function of vital organs such as heart, brain, or kidneys, monitoring of arterial blood pressure (BP) is a mainstay of hemodynamic monitoring in acutely or critically ill patients. ... ...

    Abstract Since both, hypotension and hypertension, can potentially impair the function of vital organs such as heart, brain, or kidneys, monitoring of arterial blood pressure (BP) is a mainstay of hemodynamic monitoring in acutely or critically ill patients. Arterial BP can either be obtained invasively via an arterial catheter or non-invasively. Non-invasive BP measurement provides either intermittent or continuous readings. Most commonly, an occluding upper arm cuff is used for intermittent non-invasive monitoring. BP values are then obtained either manually (by auscultation of Korotkoff sounds or palpation) or automatically (e.g., by oscillometry). For continuous non-invasive BP monitoring, the volume clamp method or arterial applanation tonometry can be used. Both techniques enable the arterial waveform and BP values to be obtained continuously. This article describes the different techniques for non-invasive BP measurement, their advantages and limitations, and their clinical applicability.
    Language English
    Publishing date 2018-01-08
    Publishing country Switzerland
    Document type Journal Article ; Review
    ZDB-ID 2775999-4
    ISSN 2296-858X
    ISSN 2296-858X
    DOI 10.3389/fmed.2017.00231
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Noninvasive Assessment of Arterial Pulse-Pressure Variation During General Anesthesia: Clinical Evaluation of a New High-Fidelity Upper Arm Cuff.

    Conter, Philippe / Briegel, Josef / Baehner, Torsten / Kreitmeier, Alois / Meidert, Agnes S / Tholl, Martin / Schwimmbeck, Franz / Bauer, Andreas / Pfeiffer, Ulrich J

    Journal of cardiothoracic and vascular anesthesia

    2023  Volume 37, Issue 8, Page(s) 1382–1389

    Abstract: Objectives: To compare noninvasive pulse-pressure variation (PPV) measurements obtained from a new high-fidelity upper arm cuff using a hydraulic coupling technique to corresponding intraarterial PPV measurements.: Design: The authors used ... ...

    Abstract Objectives: To compare noninvasive pulse-pressure variation (PPV) measurements obtained from a new high-fidelity upper arm cuff using a hydraulic coupling technique to corresponding intraarterial PPV measurements.
    Design: The authors used prospective multicenter comparison and development studies for the new high-fidelity upper arm cuff.
    Setting: The study was performed in the departments of Anesthesiology at the Ludwig-Maximilians-Universität München Hospital, the University Hospital of Bonn, and the RoMed Hospital in Rosenheim (all Germany).
    Participants: A total of 153 patients were enrolled, undergoing major abdominal surgery or neurosurgery with mechanical ventilation. For the evaluation of PPV, 1,467 paired measurements in 107 patients were available after exclusion due to predefined quality criteria.
    Interventions: Simultaneous measurements of PPV were performed from a reference femoral arterial catheter (PPV
    Measurements and main results: The comparative analysis of the included measurements showed that PPV
    Conclusions: The new high-fidelity upper arm cuff method provided a clinically reliable estimate of PPV.
    MeSH term(s) Humans ; Arm ; Blood Pressure Determination/methods ; Prospective Studies ; Blood Pressure ; Anesthesia, General
    Language English
    Publishing date 2023-04-05
    Publishing country United States
    Document type Multicenter Study ; Journal Article
    ZDB-ID 1067317-9
    ISSN 1532-8422 ; 1053-0770
    ISSN (online) 1532-8422
    ISSN 1053-0770
    DOI 10.1053/j.jvca.2023.03.040
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Identification of microRNA biomarkers simultaneously expressed in circulating extracellular vesicles and atherosclerotic plaques.

    Brandes, Florian / Meidert, Agnes S / Kirchner, Benedikt / Yu, Mia / Gebhardt, Sonja / Steinlein, Ortrud K / Dolch, Michael E / Rantner, Barbara / Tsilimparis, Nikolaos / Schelling, Gustav / Pfaffl, Michael W / Reithmair, Marlene

    Frontiers in cardiovascular medicine

    2024  Volume 11, Page(s) 1307832

    Abstract: Background: Atherosclerosis is a widespread disorder of the cardiovascular system. The early detection of plaques by circulating biomarkers is highly clinically relevant to prevent the occurrence of major complications such as stroke or heart attacks. ... ...

    Abstract Background: Atherosclerosis is a widespread disorder of the cardiovascular system. The early detection of plaques by circulating biomarkers is highly clinically relevant to prevent the occurrence of major complications such as stroke or heart attacks. It is known that extracellular vesicles (EVs) are important in intercellular communication in atherosclerotic disorders and carry many components of their cells of origin, including microRNAs (miRNAs). In this study, we test the assumption that miRNAs present in material acquired from plaques in patients undergoing surgery for atherosclerotic carotid artery stenosis are also expressed in circulating EVs obtained from the identical patients. This would allow the adoption of a liquid biopsy approach for the detection of plaques.
    Methods: We studied 22 surgical patients with atherosclerotic carotid arterial stenosis and 28 healthy controls. EVs were isolated from serum by precipitation. miRNA expression profiles of serum-derived EVs were obtained by small RNA sequencing and in plaque material simultaneously acquired from patients. A comparative analysis was performed to identify circulating atherosclerosis-associated miRNAs that are also detectable in plaques.
    Results: Seven miRNAs were found to be differentially regulated in patient serum compared with the serum of healthy controls. Of these, miR-193b-5p, miR-193a-5p, and miR-125a-3p were significantly upregulated in patients compared with that in healthy controls and present in both, circulating EVs and plaque material. An overrepresentation analysis of experimentally validated mRNA targets revealed an increased regulation of inflammation and vascular growth factors, key players in atherosclerosis and plaque formation.
    Conclusion: Our findings suggest that circulating EVs reflect plaque development in patients with symptomatic carotid artery stenosis, which can serve as biomarker candidates for detecting the presence of atherosclerotic plaques.
    Language English
    Publishing date 2024-04-25
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2781496-8
    ISSN 2297-055X
    ISSN 2297-055X
    DOI 10.3389/fcvm.2024.1307832
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Protecting Health Care Workers: Use of a Body Covering Transparent Sheet During and After Intubation of Patients With COVID-19.

    Rehm, Markus / Eichler, Julia / Meidert, Agnes S / Briegel, Josef

    Anesthesia and analgesia

    2020  Volume 131, Issue 2, Page(s) e111–e112

    MeSH term(s) Betacoronavirus ; COVID-19 ; Coronavirus Infections/prevention & control ; Coronavirus Infections/surgery ; Coronavirus Infections/transmission ; Humans ; Intubation, Intratracheal/methods ; Intubation, Intratracheal/standards ; Occupational Exposure/prevention & control ; Pandemics/prevention & control ; Personal Protective Equipment/standards ; Pneumonia, Viral/prevention & control ; Pneumonia, Viral/surgery ; Pneumonia, Viral/transmission ; SARS-CoV-2
    Keywords covid19
    Language English
    Publishing date 2020-06-08
    Publishing country United States
    Document type Letter
    ZDB-ID 80032-6
    ISSN 1526-7598 ; 0003-2999
    ISSN (online) 1526-7598
    ISSN 0003-2999
    DOI 10.1213/ANE.0000000000004939
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Do higher alarm thresholds for arterial blood pressure lead to less perioperative hypotension? A retrospective, observational cohort study.

    Meidert, Agnes S / Hornung, Roman / Christmann, Tina / Aue, Elisa / Dahal, Chetana / Dolch, Michael E / Briegel, Josef

    Journal of clinical monitoring and computing

    2022  Volume 37, Issue 1, Page(s) 275–285

    Abstract: Arterial blood pressure is one of the vital signs monitored mandatory in anaesthetised patients. Even short episodes of intraoperative hypotension are associated with increased risk for postoperative organ dysfunction such as acute kidney injury and ... ...

    Abstract Arterial blood pressure is one of the vital signs monitored mandatory in anaesthetised patients. Even short episodes of intraoperative hypotension are associated with increased risk for postoperative organ dysfunction such as acute kidney injury and myocardial injury. Since there is little evidence whether higher alarm thresholds in patient monitors can help prevent intraoperative hypotension, we analysed the blood pressure data before (group 1) and after (group 2) the implementation of altered hypotension alarm settings. The study was conducted as a retrospective observational cohort study in a large surgical centre with 32 operating theatres. Alarm thresholds for hypotension alarm for mean arterial pressure (MAP) were altered from 60 (before) to 65 mmHg for invasive measurement and 70 mmHg for noninvasive measurement. Blood pressure data from electronic anaesthesia records of 4222 patients (1982 and 2240 in group 1 and 2, respectively) with 406,623 blood pressure values undergoing noncardiac surgery were included. We analysed (A) the proportion of blood pressure measurements below the threshold among all measurements by quasi-binomial regression and (B) whether at least one blood pressure measurement below the threshold occurred by logistic regression. Hypotension was defined as MAP < 65 mmHg. There was no significant difference in overall proportions of hypotensive episodes for mean arterial pressure before and after the adjustment of alarm settings (mean proportion of values below 65 mmHg were 6.05% in group 1 and 5.99% in group 2). The risk of ever experiencing a hypotensive episode during anaesthesia was significantly lower in group 2 with an odds ratio of 0.84 (p = 0.029). In conclusion, higher alarm thresholds do not generally lead to less hypotensive episodes perioperatively. There was a slight but significant reduction of the occurrence of intraoperative hypotension in the presence of higher thresholds for blood pressure alarms. However, this reduction only seems to be present in patients with very few hypotensive episodes.
    MeSH term(s) Humans ; Arterial Pressure/physiology ; Retrospective Studies ; Postoperative Complications/diagnosis ; Monitoring, Intraoperative/adverse effects ; Hypotension/diagnosis ; Hypotension/etiology ; Cohort Studies ; Blood Pressure
    Language English
    Publishing date 2022-07-07
    Publishing country Netherlands
    Document type Observational Study ; Journal Article
    ZDB-ID 1418733-4
    ISSN 1573-2614 ; 1387-1307 ; 0748-1977
    ISSN (online) 1573-2614
    ISSN 1387-1307 ; 0748-1977
    DOI 10.1007/s10877-022-00889-z
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Intraoperative haemodynamic monitoring and management of adults having non-cardiac surgery: Guidelines of the German Society of Anaesthesiology and Intensive Care Medicine in collaboration with the German Association of the Scientific Medical Societies.

    Saugel, Bernd / Annecke, Thorsten / Bein, Berthold / Flick, Moritz / Goepfert, Matthias / Gruenewald, Matthias / Habicher, Marit / Jungwirth, Bettina / Koch, Tilo / Kouz, Karim / Meidert, Agnes S / Pestel, Gunther / Renner, Jochen / Sakka, Samir G / Sander, Michael / Treskatsch, Sascha / Zitzmann, Amelie / Reuter, Daniel A

    Journal of clinical monitoring and computing

    2024  

    Abstract: Haemodynamic monitoring and management are cornerstones of perioperative care. The goal of haemodynamic management is to maintain organ function by ensuring adequate perfusion pressure, blood flow, and oxygen delivery. We here present guidelines on " ... ...

    Abstract Haemodynamic monitoring and management are cornerstones of perioperative care. The goal of haemodynamic management is to maintain organ function by ensuring adequate perfusion pressure, blood flow, and oxygen delivery. We here present guidelines on "Intraoperative haemodynamic monitoring and management of adults having non-cardiac surgery" that were prepared by 18 experts on behalf of the German Society of Anaesthesiology and Intensive Care Medicine (Deutsche Gesellschaft für Anästhesiologie und lntensivmedizin; DGAI).
    Language English
    Publishing date 2024-02-21
    Publishing country Netherlands
    Document type Journal Article ; Review
    ZDB-ID 1418733-4
    ISSN 1573-2614 ; 1387-1307 ; 0748-1977
    ISSN (online) 1573-2614
    ISSN 1387-1307 ; 0748-1977
    DOI 10.1007/s10877-024-01132-7
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Correction to: How to measure blood pressure using an arterial catheter: a systematic 5-step approach.

    Saugel, Bernd / Kouz, Karim / Meidert, Agnes S / Schulte-Uentrop, Leonie / Romagnoli, Stefano

    Critical care (London, England)

    2020  Volume 24, Issue 1, Page(s) 374

    Abstract: An amendment to this paper has been published and can be accessed via the original article. ...

    Abstract An amendment to this paper has been published and can be accessed via the original article.
    Language English
    Publishing date 2020-06-23
    Publishing country England
    Document type Journal Article ; Published Erratum
    ZDB-ID 2051256-9
    ISSN 1466-609X ; 1364-8535
    ISSN (online) 1466-609X
    ISSN 1364-8535
    DOI 10.1186/s13054-020-03093-0
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  9. Article ; Online: Extensive blood transcriptome analysis reveals cellular signaling networks activated by circulating glycocalyx components reflecting vascular injury in COVID-19.

    Borrmann, Melanie / Brandes, Florian / Kirchner, Benedikt / Klein, Matthias / Billaud, Jean-Noël / Reithmair, Marlene / Rehm, Markus / Schelling, Gustav / Pfaffl, Michael W / Meidert, Agnes S

    Frontiers in immunology

    2023  Volume 14, Page(s) 1129766

    Abstract: Background: Degradation of the endothelial protective glycocalyx layer during COVID-19 infection leads to shedding of major glycocalyx components. These circulating proteins and their degradation products may feedback on immune and endothelial cells and ...

    Abstract Background: Degradation of the endothelial protective glycocalyx layer during COVID-19 infection leads to shedding of major glycocalyx components. These circulating proteins and their degradation products may feedback on immune and endothelial cells and activate molecular signaling cascades in COVID-19 associated microvascular injury. To test this hypothesis, we measured plasma glycocalyx components in patients with SARS-CoV-2 infection of variable disease severity and identified molecular signaling networks activated by glycocalyx components in immune and endothelial cells.
    Methods: We studied patients with RT-PCR confirmed COVID-19 pneumonia, patients with COVID-19 Acute Respiratory Distress Syndrome (ARDS) and healthy controls (wildtype, n=20 in each group) and measured syndecan-1, heparan sulfate and hyaluronic acid. The in-silico construction of signaling networks was based on RNA sequencing (RNAseq) of mRNA transcripts derived from blood cells and of miRNAs isolated from extracellular vesicles from the identical cohort. Differentially regulated RNAs between groups were identified by gene expression analysis. Both RNAseq data sets were used for network construction of circulating glycosaminoglycans focusing on immune and endothelial cells.
    Results: Plasma concentrations of glycocalyx components were highest in COVID-19 ARDS. Hyaluronic acid plasma levels in patients admitted with COVID-19 pneumonia who later developed ARDS during hospital treatment (n=8) were significantly higher at hospital admission than in patients with an early recovery. RNAseq identified hyaluronic acid as an upregulator of TLR4 in pneumonia and ARDS. In COVID-19 ARDS, syndecan-1 increased IL-6, which was significantly higher than in pneumonia. In ARDS, hyaluronic acid activated NRP1, a co-receptor of activated VEGFA, which is associated with pulmonary vascular hyperpermeability and interacted with VCAN (upregulated), a proteoglycan important for chemokine communication.
    Conclusions: Circulating glycocalyx components in COVID-19 have distinct biologic feedback effects on immune and endothelial cells and result in upregulation of key regulatory transcripts leading to further immune activation and more severe systemic inflammation. These consequences are most pronounced during the early hospital phase of COVID-19 before pulmonary failure develops. Elevated levels of circulating glycocalyx components may early identify patients at risk for microvascular injury and ARDS. The timely inhibition of glycocalyx degradation could provide a novel therapeutic approach to prevent the development of ARDS in COVID-19.
    MeSH term(s) Humans ; Glycocalyx/metabolism ; Endothelial Cells ; Syndecan-1/metabolism ; Vascular System Injuries/metabolism ; Hyaluronic Acid/metabolism ; COVID-19/metabolism ; SARS-CoV-2 ; Respiratory Distress Syndrome/drug therapy ; Gene Expression Profiling
    Chemical Substances Syndecan-1 ; Hyaluronic Acid (9004-61-9)
    Language English
    Publishing date 2023-01-26
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2606827-8
    ISSN 1664-3224 ; 1664-3224
    ISSN (online) 1664-3224
    ISSN 1664-3224
    DOI 10.3389/fimmu.2023.1129766
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  10. Article ; Online: Exhaled Breath and Oxygenator Sweep Gas Propionaldehyde in Acute Respiratory Distress Syndrome.

    Meidert, Agnes S / Choukèr, Alexander / Praun, Siegfried / Schelling, Gustav / Dolch, Michael E

    Molecules (Basel, Switzerland)

    2020  Volume 26, Issue 1

    Abstract: Background: Oxidative stress-induced lipid peroxidation (LPO) due to neutrophil-derived reactive oxygen species plays a key role in the early stage of the acute respiratory distress syndrome (ARDS). Monitoring of oxidative stress in this patient ... ...

    Abstract Background: Oxidative stress-induced lipid peroxidation (LPO) due to neutrophil-derived reactive oxygen species plays a key role in the early stage of the acute respiratory distress syndrome (ARDS). Monitoring of oxidative stress in this patient population is of great interest, and, ideally, this can be done noninvasively. Recently, propionaldehyde, a volatile chemical compound (VOC) released during LPO, was identified in the breath of lung transplant recipients as a marker of oxidative stress. The aim of the present study was to identify if markers of oxidative stress appear in the oxygenator outflow gas of patients with severe ARDS treated with veno-venous extracorporeal membrane oxygenation (ECMO).
    Methods: The present study included patients with severe ARDS treated with veno-venous ECMO. Concentrations of acetone, isoprene, and propionaldehyde were measured in inspiratory air, exhaled breath, and oxygenator inflow and outflow gas at corresponding time points. Ion-molecule reaction mass spectrometry was used to measure VOCs in a sequential order within the first 24 h and on day three after ECMO initiation.
    Results: Nine patients (5 female, 4 male; age = 42.1 ± 12.2 year) with ARDS and already established ECMO therapy (pre-ECMO PaO
    Conclusions: Acetone, isoprene, and propionaldehyde appear in breath and oxygenator outflow gas in comparable amounts. This allows for the measurement of these VOCs in a critically ill patient population via the ECMO oxygenator outflow gas without the need of ventilator circuit manipulation.
    MeSH term(s) Adolescent ; Adult ; Aldehydes/analysis ; Breath Tests ; Extracorporeal Membrane Oxygenation/methods ; Female ; Humans ; Male ; Middle Aged ; Oxygenators/statistics & numerical data ; Pilot Projects ; Respiration, Artificial ; Respiratory Distress Syndrome/metabolism ; Respiratory Distress Syndrome/pathology ; Respiratory Distress Syndrome/therapy
    Chemical Substances Aldehydes ; propionaldehyde (AMJ2B4M67V)
    Language English
    Publishing date 2020-12-31
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 1413402-0
    ISSN 1420-3049 ; 1431-5165 ; 1420-3049
    ISSN (online) 1420-3049
    ISSN 1431-5165 ; 1420-3049
    DOI 10.3390/molecules26010145
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