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Krondorf M, Bittner S, Plettemeier D, Knopp A, Wikelski M. ICARUS-Very Low Power Satellite-Based IoT. Sensors (Basel) 2022; 22:6329. [PMID: 36080787 PMCID: PMC9460258 DOI: 10.3390/s22176329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/05/2022] [Accepted: 08/19/2022] [Indexed: 06/15/2023]
Abstract
The ICARUS (International Cooperation for Animal Research Using Space) satellite IoT system was launched in 2020 to observe the life of animals on Earth: their migratory routes, living conditions, and causes of death. These findings will aid species conservation, protect ecosystem services by animals, measure weather and climate, and help forecast the spread of infectious zoonotic diseases and possibly natural disasters. The aim of this article is to explain the system design of ICARUS. Essential components are 'wearables for wildlife', miniature on-animal sensors, quantifying the health of animals and the surrounding environment on the move, and transmitting artificially intelligent summaries of these data globally. We introduce a new class of Internet-of-things (IoT) waveforms-the random-access, very-low-power, wide-area networks (RA-vLPWANs) which enable uncoordinated multiple access at very-low-signal power and low-signal-to-noise ratios. RA-vLPWANs used in ICARUS solve the problems hampering conventional low-power wide area network (LPWAN) IoT systems when applied to space communications. Prominent LPWANs are LoRA, SigFox, MIOTY, ESSA, NB-IoT (5G), or SCADA. Hardware and antenna aspects in the ground and the space segment are given to explain practical system constraints.
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Affiliation(s)
- Marco Krondorf
- Faculty of Engineering, HTWK Leipzig, University of Applied Sciences, 04277 Leipzig, Germany
| | | | - Dirk Plettemeier
- Photonics and Antenna Design, TU Dresden, 01062 Dresden, Germany
| | - Andreas Knopp
- Institute of Information Technology, University of the Bundeswehr Munich, 85579 Neubiberg, Germany
- Space Systems Academic Group, Naval Postgraduate School, Monterey, CA 93943, USA
| | - Martin Wikelski
- Department of Migration, Max Planck Institute of Animal Behavior, 78315 Radolfzell, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78464 Konstanz, Germany
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Tadayon P, Felderhoff T, Staude G, Knopp A. Mobile System for the Prevention, Diagnosis, and Personalized Treatment of Neck Pain Under a Patient’s Everyday Life Circumstances. Current Directions in Biomedical Engineering 2019. [DOI: 10.1515/cdbme-2019-0065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
This work presents a new system concept for the prevention, diagnosis and interactive treatment of neck pain. It comprises two measurement units worn at the head and the torso, a smartphone/tablet and a medical assistance software. The system aims to provide mobile measurement of full neck movement including rotatory and translatory movements under a patients everyday life circumstances. Multiple features including biofeedback and therapy exercises are intended to be individually configurable according to the specific medical indications of the patient. In addition to the system concept the current implementation state comprising the two measurement units and a visualization app running on a tablet is presented.
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Affiliation(s)
- Puian Tadayon
- Research Center for BioMedical Technology (BMT), Fachhochschule Dortmund, Sonnenstr. 96, Dortmund , Germany
| | - Thomas Felderhoff
- Research Center for BioMedical Technology (BMT), Fachhochschule Dortmund, Dortmund , Germany
| | - Gerhard Staude
- Chair of Signal Processing (EIT 3.2), Munich University of the Bundeswehr, Neubiberg , Germany
| | - Andreas Knopp
- Chair of Signal Processing (EIT 3.2), Munich University of the Bundeswehr, Neubiberg , Germany
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Wulf M, Eitner L, Felderhoff T, Özgül Ö, Staude G, Maier C, Knopp A, Höffken O. Evaluation of an automated analysis for pain-related evoked potentials. Current Directions in Biomedical Engineering 2017. [DOI: 10.1515/cdbme-2017-0087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AbstractThis paper presents initial steps towards an auto-mated analysis for pain-related evoked potentials (PREP) to achieve a higher objectivity and non-biased examination as well as a reduction in the time expended during clinical daily routines. While manually examining, each epoch of an en-semble of stimulus-locked EEG signals, elicited by electrical stimulation of predominantly intra-epidermal small nerve fibers and recorded over the central electrode (Cz), is in-spected for artifacts before calculating the PREP by averag-ing the artifact-free epochs. Afterwards, specific peak-latencies (like the P0-, N1 and P1-latency) are identified as certain extrema in the PREP’s waveform. The proposed automated analysis uses Pearson’s correlation and low-pass differentiation to perform these tasks. To evaluate the auto-mated analysis’ accuracy its results of 232 datasets were compared to the results of the manually performed examina-tion. Results of the automated artifact rejection were compa-rable to the manual examination. Detection of peak-latencies was more heterogeneous, indicating some sensitivity of the detected events upon the criteria used during data examina-tion.
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Affiliation(s)
- Michael Wulf
- Research Center for BioMedicalTechnology (BMT), University of Applied Sciences and Arts, Sonnenstr. 96, 44139 Dortmund, Germany
| | - Lynn Eitner
- Department of Pain Medicine, BG Universitätsklinikum Bergmannsheil Bochum, Bochum, Germany
| | - Thomas Felderhoff
- Research Center for BioMedicalTechnology (BMT), University of Applied Sciences and Arts, Dortmund, Germany
| | - Özüm Özgül
- Department of Neurology, BG Universitätsklinikum Bergmannsheil Bochum, Bochum, Germany
| | - Gerhard Staude
- Chair of Signal Processing (EIT 3.2), Universität der Bundeswehr München, Neubiberg, Germany
| | - Christoph Maier
- Department of Pain Medicine, BG Universitätsklinikum Bergmannsheil Bochum, Bochum, Germany
| | - Andreas Knopp
- Chair of Signal Processing (EIT 3.2), Universität der Bundeswehr München, Neubiberg, Germany
| | - Oliver Höffken
- Department of Neurology, BG Universitätsklinikum Bergmannsheil Bochum, Bochum, Germany
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Tadayon P, Felderhoff T, Knopp A, Staude G. Fusion of inertial and magnetic sensors for 3D position and orientation estimation. Annu Int Conf IEEE Eng Med Biol Soc 2017; 2016:3362-3365. [PMID: 28269024 DOI: 10.1109/embc.2016.7591448] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This paper presents a new method for 3D position and orientation estimation based on the magnetic field generated by a single coil and the fusion of low power magnetometers and inertial sensors. The fixed spatial relationship between the sensors is exploited to solve the ambiguity problem that occurs when only a single coil is employed. In this context a new positioning algorithm is developed and verified by simulations. Using a single coil instead of three coils as common in conventional magnetic field based systems brings a benefit both regarding power consumption and construction size. Moreover, as the proposed system requires no line of sight between source and sensors, it is ideally suited for portable, location-independent applications such as the mobile assessment of a persons' head to torso posture and movement e.g. for the purpose of examining causes for chronic pain in the cervical spine area under conditions of daily life.
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Capetian P, Azmitia L, Pauly MG, Krajka V, Stengel F, Bernhardi EM, Klett M, Meier B, Seibler P, Stanslowsky N, Moser A, Knopp A, Gillessen-Kaesbach G, Nikkhah G, Wegner F, Döbrössy M, Klein C. Plasmid-Based Generation of Induced Neural Stem Cells from Adult Human Fibroblasts. Front Cell Neurosci 2016; 10:245. [PMID: 27822179 PMCID: PMC5075569 DOI: 10.3389/fncel.2016.00245] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/06/2016] [Indexed: 01/01/2023] Open
Abstract
Direct reprogramming from somatic to neural cell types has become an alternative to induced pluripotent stem cells. Most protocols employ viral expression systems, posing the risk of random genomic integration. Recent developments led to plasmid-based protocols, lowering this risk. However, these protocols either relied on continuous presence of a variety of small molecules or were only able to reprogram murine cells. We therefore established a reprogramming protocol based on vectors containing the Epstein-Barr virus (EBV)-derived oriP/EBNA1 as well as the defined expression factors Oct3/4, Sox2, Klf4, L-myc, Lin28, and a small hairpin directed against p53. We employed a defined neural medium in combination with the neurotrophins bFGF, EGF and FGF4 for cultivation without the addition of small molecules. After reprogramming, cells demonstrated a temporary increase in the expression of endogenous Oct3/4. We obtained induced neural stem cells (iNSC) 30 days after transfection. In contrast to previous results, plasmid vectors as well as a residual expression of reprogramming factors remained detectable in all cell lines. Cells showed a robust differentiation into neuronal (72%) and glial cells (9% astrocytes, 6% oligodendrocytes). Despite the temporary increase of pluripotency-associated Oct3/4 expression during reprogramming, we did not detect pluripotent stem cells or non-neural cells in culture (except occasional residual fibroblasts). Neurons showed electrical activity and functional glutamatergic synapses. Our results demonstrate that reprogramming adult human fibroblasts to iNSC by plasmid vectors and basic neural medium without small molecules is possible and feasible. However, a full set of pluripotency-associated transcription factors may indeed result in the acquisition of a transient (at least partial) pluripotent intermediate during reprogramming. In contrast to previous reports, the EBV-based plasmid system remained present and active inside the cells at all time points.
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Affiliation(s)
- Philipp Capetian
- Institute of Neurogenetics, University of LübeckLübeck, Germany; Department of Neurology, University of LübeckLübeck, Germany
| | - Luis Azmitia
- Department of Neurosurgery, University of Kiel Kiel, Germany
| | - Martje G Pauly
- Institute of Neurogenetics, University of Lübeck Lübeck, Germany
| | - Victor Krajka
- Institute of Neurogenetics, University of Lübeck Lübeck, Germany
| | - Felix Stengel
- Institute of Neurogenetics, University of Lübeck Lübeck, Germany
| | | | - Mariana Klett
- Laboratory of Stereotaxy and Interventional Neuroscience, Department of Stereotactic and Functional Neuroscience, University Medical Center Freiburg Freiburg im Breisgau, Germany
| | - Britta Meier
- Institute of Neurogenetics, University of Lübeck Lübeck, Germany
| | - Philip Seibler
- Institute of Neurogenetics, University of Lübeck Lübeck, Germany
| | | | - Andreas Moser
- Department of Neurology, University of Lübeck Lübeck, Germany
| | - Andreas Knopp
- Institute of Physiology, University of Kiel Kiel, Germany
| | | | - Guido Nikkhah
- Department of Neurosurgery, University of Erlangen-Nuremberg Erlangen, Germany
| | - Florian Wegner
- Department of Neurology, Hannover Medical School Hanover, Germany
| | - Máté Döbrössy
- Laboratory of Stereotaxy and Interventional Neuroscience, Department of Stereotactic and Functional Neuroscience, University Medical Center Freiburg Freiburg im Breisgau, Germany
| | - Christine Klein
- Institute of Neurogenetics, University of Lübeck Lübeck, Germany
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Wulf M, Staude G, Knopp A, Felderhoff T. Efficient design of FIR filter based low-pass differentiators for biomedical signal processing. Current Directions in Biomedical Engineering 2016. [DOI: 10.1515/cdbme-2016-0048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
This paper describes an alternative design of linear phase low-pass differentiators with a finite impulse response (type III FIR filter). To reduce the number of necessary filter coefficients, the differentiator’s transfer function is approximated by a Fourier series of a triangle function. Thereby the filter’s transition steepness towards the stopband is intentionally reduced. It can be shown that the proposed design of low-pass differentiators yields to similar results as other published design recommendations, while the filter order can be significantly reduced.
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Affiliation(s)
- Michael Wulf
- Research Center for BioMedical Technology (BMT), Fachhochschule Dortmund, Sonnenstr. 96, 44139 Dortmund, Germany
| | - Gerhard Staude
- Chair of Signal Processing (EIT 3.2), Munich University of the Bundeswehr, Neubiberg, Germany
| | - Andreas Knopp
- Chair of Signal Processing (EIT 3.2), Munich University of the Bundeswehr, Neubiberg, Germany
| | - Thomas Felderhoff
- Research Center for BioMedical Technology (BMT), Fachhochschule Dortmund, Dortmund, Germany
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Nickel AG, von Hardenberg A, Hohl M, Löffler JR, Kohlhaas M, Becker J, Reil JC, Kazakov A, Bonnekoh J, Stadelmaier M, Puhl SL, Wagner M, Bogeski I, Cortassa S, Kappl R, Pasieka B, Lafontaine M, Lancaster CRD, Blacker TS, Hall AR, Duchen MR, Kästner L, Lipp P, Zeller T, Müller C, Knopp A, Laufs U, Böhm M, Hoth M, Maack C. Reversal of Mitochondrial Transhydrogenase Causes Oxidative Stress in Heart Failure. Cell Metab 2015; 22:472-84. [PMID: 26256392 DOI: 10.1016/j.cmet.2015.07.008] [Citation(s) in RCA: 250] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 05/10/2015] [Accepted: 07/08/2015] [Indexed: 12/11/2022]
Abstract
Mitochondrial reactive oxygen species (ROS) play a central role in most aging-related diseases. ROS are produced at the respiratory chain that demands NADH for electron transport and are eliminated by enzymes that require NADPH. The nicotinamide nucleotide transhydrogenase (Nnt) is considered a key antioxidative enzyme based on its ability to regenerate NADPH from NADH. Here, we show that pathological metabolic demand reverses the direction of the Nnt, consuming NADPH to support NADH and ATP production, but at the cost of NADPH-linked antioxidative capacity. In heart, reverse-mode Nnt is the dominant source for ROS during pressure overload. Due to a mutation of the Nnt gene, the inbred mouse strain C57BL/6J is protected from oxidative stress, heart failure, and death, making its use in cardiovascular research problematic. Targeting Nnt-mediated ROS with the tetrapeptide SS-31 rescued mortality in pressure overload-induced heart failure and could therefore have therapeutic potential in patients with this syndrome.
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Affiliation(s)
- Alexander G Nickel
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | | | - Mathias Hohl
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | - Joachim R Löffler
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | - Michael Kohlhaas
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | - Janne Becker
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | - Jan-Christian Reil
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | - Andrey Kazakov
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | - Julia Bonnekoh
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | - Moritz Stadelmaier
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | - Sarah-Lena Puhl
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | - Michael Wagner
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | - Ivan Bogeski
- Department of Biophysics, CIPMM, School of Medicine, Saarland University, 66421 Homburg, Germany
| | | | - Reinhard Kappl
- Department of Biophysics, CIPMM, School of Medicine, Saarland University, 66421 Homburg, Germany
| | - Bastian Pasieka
- Department of Biophysics, CIPMM, School of Medicine, Saarland University, 66421 Homburg, Germany
| | - Michael Lafontaine
- Department of Structural Biology, Saarland University, 66421 Homburg, Germany
| | - C Roy D Lancaster
- Department of Structural Biology, Saarland University, 66421 Homburg, Germany
| | - Thomas S Blacker
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK; Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
| | - Andrew R Hall
- The Hatter Cardiovascular Institute, University College London, London WC1E 6BT, UK
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Lars Kästner
- Institut für Zellbiologie, Universität des Saarlandes, 66421 Homburg, Germany
| | - Peter Lipp
- Institut für Zellbiologie, Universität des Saarlandes, 66421 Homburg, Germany
| | - Tanja Zeller
- Klinik für Allgemeine und Interventionelle Kardiologie, Universitäres Herzzentrum Hamburg, 20246 Hamburg, Germany; Deutsches Zentrum für Herzkreislaufforschung (DZHK e.V.), Partner Site Hamburg/Lübeck/Kiel, Germany
| | - Christian Müller
- Klinik für Allgemeine und Interventionelle Kardiologie, Universitäres Herzzentrum Hamburg, 20246 Hamburg, Germany; Deutsches Zentrum für Herzkreislaufforschung (DZHK e.V.), Partner Site Hamburg/Lübeck/Kiel, Germany
| | - Andreas Knopp
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | - Ulrich Laufs
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | - Michael Böhm
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany
| | - Markus Hoth
- Department of Biophysics, CIPMM, School of Medicine, Saarland University, 66421 Homburg, Germany
| | - Christoph Maack
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Germany.
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Kohlhaas M, Liu T, Knopp A, Zeller T, Ong MF, Böhm M, O'Rourke B, Maack C. Elevated cytosolic Na+ increases mitochondrial formation of reactive oxygen species in failing cardiac myocytes. Circulation 2010; 121:1606-13. [PMID: 20351235 DOI: 10.1161/circulationaha.109.914911] [Citation(s) in RCA: 251] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Oxidative stress is causally linked to the progression of heart failure, and mitochondria are critical sources of reactive oxygen species in failing myocardium. We previously observed that in heart failure, elevated cytosolic Na(+) ([Na(+)](i)) reduces mitochondrial Ca(2+) ([Ca(2+)](m)) by accelerating Ca(2+) efflux via the mitochondrial Na(+)/Ca(2+) exchanger. Because the regeneration of antioxidative enzymes requires NADPH, which is indirectly regenerated by the Krebs cycle, and Krebs cycle dehydrogenases are activated by [Ca(2+)](m), we speculated that in failing myocytes, elevated [Na(+)](i) promotes oxidative stress. METHODS AND RESULTS We used a patch-clamp-based approach to simultaneously monitor cytosolic and mitochondrial Ca(2+) and, alternatively, mitochondrial H(2)O(2) together with NAD(P)H in guinea pig cardiac myocytes. Cells were depolarized in a voltage-clamp mode (3 Hz), and a transition of workload was induced by beta-adrenergic stimulation. During this transition, NAD(P)H initially oxidized but recovered when [Ca(2+)](m) increased. The transient oxidation of NAD(P)H was closely associated with an increase in mitochondrial H(2)O(2) formation. This reactive oxygen species formation was potentiated when mitochondrial Ca(2+) uptake was blocked (by Ru360) or Ca(2+) efflux was accelerated (by elevation of [Na(+)](i)). In failing myocytes, H(2)O(2) formation was increased, which was prevented by reducing mitochondrial Ca(2+) efflux via the mitochondrial Na(+)/Ca(2+) exchanger. CONCLUSIONS Besides matching energy supply and demand, mitochondrial Ca(2+) uptake critically regulates mitochondrial reactive oxygen species production. In heart failure, elevated [Na(+)](i) promotes reactive oxygen species formation by reducing mitochondrial Ca(2+) uptake. This novel mechanism, by which defects in ion homeostasis induce oxidative stress, represents a potential drug target to reduce reactive oxygen species production in the failing heart.
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Affiliation(s)
- Michael Kohlhaas
- Universitätsklinikum des Saarlandes, Klinik für Innere Medizin III, 66421 Homburg, Germany
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Dorner T, Knopp A, Stettner H, Freidl W. [Gender specific differences in the frequency of admission to intensive care units, duration of stay and the application of intensive medical care measures in men and women aged 75 years and above in an Austrian region]. Gesundheitswesen 2009; 72:e72-5. [PMID: 19795344 DOI: 10.1055/s-0029-1237731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE It was the aim of this study to evaluate the frequency of admission to intensive care units, duration of stay and application of intensive care treatments in patients aged 75 years and above and to analyse possible gender specific differences. METHODS Analysis of hospital in-patient data of all hospitals of a southern Austrian region (federal state of Carinthia). RESULTS In the year 2003, 4.7% of the men and 3.2% of the women aged 75 years and above were treated in intensive care units (p<0.001). This gender specific difference was independent of the reason for the intensive care admission. The mean duration of stay in intensive care units was longer for 75-79 year old men compared to women (6.38 vs. 4.91 days, p<0.01). Typical intensive care treatments like mechanical ventilation, artificial airways and vasoactive medication were applied more often to men than to women. CONCLUSION In the aged there are marked gender specific differences in the application of intensive care treatments, especially in the end-of-life state in Austria. The reasons for these differences should be subject of future research.
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Affiliation(s)
- T Dorner
- Institut für Sozialmedizin und Epidemiologie, Medizinische Universität Graz.
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Knopp U, Knopp A, Stellmacher F, Reusche E, Löning M, Kantelhardt SR, Domarus HV, Arnold H, Giese A. A non-midline spheno-orbital encephalocele in a newborn. ACTA ACUST UNITED AC 2009; 70:43-7. [PMID: 19191207 DOI: 10.1055/s-0028-1082321] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Basal encephaloceles in western countries occur in 1 of every 35 000-40 000 live births; with an incidence of less than 10% they are the least common of all encephaloceles. Certain subtypes such as transsphenoidal variants may be as rare as 1 in 700 000 live births. These rare encephaloceles are classified into five anatomic types: spheno-ethmodial, transsphenoidal, spheno-orbital, transethmoidal, and spheno-maxillary. Here we present an exceedingly rare variant of a non-midline basal encephalocele of the spheno-orbital type, which was treated by resection of the encephalocele, which contained dysplastic central nervous system tissue, on day four post partum. The patient had no neurological deficits and a six year follow-up showed a normal intellect and a good cosmetic result.
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Affiliation(s)
- U Knopp
- Department of Neurosurgery, University Hospital Lübeck, Lübeck, Germany
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11
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Knopp A, Frahm C, Fidzinski P, Witte OW, Behr J. Loss of GABAergic neurons in the subiculum and its functional implications in temporal lobe epilepsy. Brain 2008; 131:1516-27. [PMID: 18504292 DOI: 10.1093/brain/awn095] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Clinical and experimental evidence suggest that the subiculum plays an important role in the maintenance of temporal lobe seizures. Using the pilocarpine-model of temporal lobe epilepsy (TLE), the present study examines the vulnerability of GABAergic subicular interneurons to recurrent seizures and determines its functional implications. In the subiculum of pilocarpine-treated animals, the density of glutamic acid decarboxylase (GAD) mRNA-positive cells was reduced in all layers. Our data indicate a substantial loss of parvalbumin-immunoreactive neurons in the pyramidal cell and molecular layer whereas calretinin-immunoreactive cells were predominantly reduced in the molecular layer. Though the subiculum of pilocarpine-treated rats showed an increased intensity of GAD65 immunoreactivity, the density of GAD65 containing synaptic terminals in the pyramidal cell layer was decreased indicating an increase in the GAD65 intensity of surviving synaptic terminals. We observed a decrease in evoked inhibitory post-synaptic currents that mediate dendritic inhibition as well as a decline in the frequency of miniature inhibitory post-synaptic currents (mIPSCs) that are restricted to the perisomatic region. The decrease in mIPSC frequency (-30%) matched with the reduced number of perisomatic GAD-positive terminals (-28%) suggesting a decrease of pre-synaptic GABAergic input onto pyramidal cells in epileptic animals. Though cell loss in the subiculum has not been considered as a pathogenic factor in human and experimental TLE, our data suggest that the vulnerability of subicular GABAergic interneurons causes an input-specific disturbance of the subicular inhibitory system.
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Affiliation(s)
- Andreas Knopp
- Dept. of Psychiatry and Psychotherapy, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
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Stahlmann N, Härtel C, Knopp A, Gehring B, Kiecksee H, Thyen U. Predictive value of neurodevelopmental assessment versus evaluation of general movements for motor outcome in preterm infants with birth weights <1500 g. Neuropediatrics 2007; 38:91-9. [PMID: 17712738 DOI: 10.1055/s-2007-984450] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
PURPOSE The aim of this study was to make a comparison of predictive values of neurodevelopmental assessment and evaluation of videotaped spontaneous movements of premature infants for motor outcome. METHODS We performed a prospective longitudinal study of 103 VLBW infants, 96 (455-1490 g, 24-35 weeks gestational age) including (a) a neurodevelopmental assessment based on criteria by Amiel-Tison/Grenier at 40 weeks postconceptional age, 3 and 20 months corrected age; (b) an evaluation of general movements with fidgety character, based on criteria by Prechtl, at 3 months; and (c) a standardized testing using the Griffiths Developmental Motor Scale at 20 months. We calculated sensitivity, specificity and predictive values for each method. RESULTS For predicting motor outcome, the assessment of general movements (GM) had a positive predictive value of 89% and negative predictive value of 84%; neurodevelopmental assessment (NA) at 40 weeks had a positive predictive value of 33% and negative predictive value of 88%, respectively, with similar results for neurodevelopmental assessment at age 3 months. CONCLUSIONS Normal motor outcome of VLBW infants may be accurately predicted by clinical neurodevelopmental assessment, but for adverse outcomes, evaluation of general movements (fidgety movements) is superior. GM assessment has a high predictive value, especially for CP, but it needs to be complemented by NA for non-CP outcomes. It is a simple, repeatable and non-intrusive technique, and may be a valuable method for the early detection of central nervous system impairment in VLBW infants in routine follow-up.
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Affiliation(s)
- N Stahlmann
- University Lübeck, Children and Adolescents Medical Center, Lübeck, Germany
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13
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Knopp A, Rüppel H. Calcium-sensitive downregulation of the transduction chain in rod photoreceptors of the rat retina. Biophys J 2006; 91:1078-89. [PMID: 16698783 PMCID: PMC1563759 DOI: 10.1529/biophysj.106.082271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In vertebrate rod outer segments phototransduction is suggested to be modulated by intracellular Ca. We aimed at verifying this hypothesis by recording saturated photosignals in the rat retina after single and double flashes of light and determining the time t(c) to the beginning of the signal recovery. The time course of Ca(i) after a flash was calculated from a change of the spatial Ca(2+) concentration profile recorded in the space between the rods. After single flashes t(c) increased linearly with the logarithm of flash intensity, confirming the assumption that t(c) is determined by deactivation of a single species X* in the phototransduction cascade. The photoresponse was shortened up to 45% if the test flash was preceded by a conditioning preflash. The shortening depended on the reduction of Ca(i) induced by the preflash. The data suggest that the phototransduction gain determining the amount of activated X* is regulated by a Ca(i)-dependent mechanism in a short time period (<800 ms) after the test flash. Lowering of Ca(i) by a preflash reduced the gain up to 20% compared to its value in a dark-adapted rod. The relation between phototransduction gain and Ca(i) revealed a K(1/2) value close to the dark level of Ca(i).
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Affiliation(s)
- Andreas Knopp
- Max-Volmer-Institut of Biophysical Chemistry, Technical University Berlin, Berlin, Germany.
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14
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Abstract
PURPOSE This study determines synaptic and intrinsic alterations of subicular pyramidal cells that are associated with activity recorded in patients suffering from temporal lobe epilepsy. METHODS Electroencephalograms with sphenoidal electrodes were correlated with in vitro single cell recordings of subicular pyramidal cells from the corresponding resected epileptic tissue. We determined alterations of synaptic and intrinsic properties of subicular pyramidal cells that accompany spontaneous rhythmic activity in human sclerotic and nonsclerotic epileptic tissue. RESULTS We found that in sclerotic, but also in nonsclerotic hippocampal tissue, the subiculum showed cellular and synaptic changes that were associated with spontaneous rhythmic activity correlated to the occurrence and frequency of interictal discharges recorded in the electroencephalograms of the corresponding patients. CONCLUSIONS Even though Ammon's horn sclerosis (AHS) in resected hippocampi from patients suffering from temporal lobe epilepsy has important prognostic implications for freedom from seizures postoperatively, we report here that both synaptic and intrinsic alterations enhance seizure susceptibility of the subiculum also in the absence of classical AHS.
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Affiliation(s)
- Christian Wozny
- Neuroscience Research Center of the Charité, Humboldt University Berlin, Berlin, Germany
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15
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Knopp A, Kivi A, Wozny C, Heinemann U, Behr J. Cellular and network properties of the subiculum in the pilocarpine model of temporal lobe epilepsy. J Comp Neurol 2005; 483:476-88. [PMID: 15700275 DOI: 10.1002/cne.20460] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The subiculum was recently shown to be crucially involved in the generation of interictal activity in human temporal lobe epilepsy. Using the pilocarpine model of epilepsy, this study examines the anatomical substrates for network hyperexcitability recorded in the subiculum. Regular- and burst-spiking subicular pyramidal cells were stained with fluorescence dyes and reconstructed to analyze seizure-induced alterations of the dendritic and axonal system. In control animals burst-spiking cells outnumbered regular-spiking cells by about two to one. Regular- and burst-spiking cells were characterized by extensive axonal branching and autapse-like contacts, suggesting a high intrinsic connectivity. In addition, subicular axons projecting to CA1 indicate a CA1-subiculum-CA1 circuit. In the subiculum of pilocarpine-treated rats we found an enhanced network excitability characterized by spontaneous rhythmic activity, polysynaptic responses, and all-or-none evoked bursts of action potentials. In pilocarpine-treated rats the subiculum showed cell loss of about 30%. The ratio of regular- and burst-spiking cells was practically inverse as compared to control preparations. A reduced arborization and spine density in the proximal part of the apical dendrites suggests a partial deafferentiation from CA1. In pilocarpine-treated rats no increased axonal outgrowth of pyramidal cells was observed. Hence, axonal sprouting of subicular pyramidal cells is not mandatory for the development of the pathological events. We suggest that pilocarpine-induced seizures cause an unmasking or strengthening of synaptic contacts within the recurrent subicular network.
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Affiliation(s)
- Andreas Knopp
- Neuroscience Research Center of the Charité, Humboldt University of Berlin, D-10117 Berlin, Germany
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16
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Rabe C, Paar WD, Knopp A, Münch J, Musch A, Rockstroh J, Martin S, Sauerbruch T, Dumoulin FL. [Malaria in the emergency room. Results of the emergency treatment of 137 patients with symptomatic malaria]. Dtsch Med Wochenschr 2005; 130:145-9. [PMID: 15662580 DOI: 10.1055/s-2005-837386] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To assess characteristics and outcome of emergency patients with acute malaria. PATIENTS AND METHODS We retrospectively assessed the clinical and laboratory parameters of 137 consecutive patients (87 males, 50 females; median age 37 years, range 17 - 67 years) presenting with acute malaria to our tertiary care center between 1992 and 2002. RESULTS Falciparum malaria was diagnosed in 116/137 and tertian malaria in 19/137 patients; a single patient was infected with both parasites while in another case the type of parasite remained unclear. Infections were acquired in Africa (121), Asia , and in the Americas . One traveler visited multiple continents. Only 36 % (50/137) of patients had used malaria chemoprophylaxis. 128/137 patients were treated as in-patients; 22 of these had to be treated on an intensive care unit. According to the criteria of the German Society of Tropical Medicine, 44/137 (32 %; 95 % confidence interval (CI): 25 - 40 %) patients suffered from complicated malaria. The overall mortality rate was 2/137 (1.5 %; 95 % CI: 0,4 - 5.2 %); the mortality rate of complicated malaria tropica was 2/44 (4,5 %; 95 % CI 1,3 - 15 %). Patients with complicated malaria were significantly older than those with uncomplicated malaria. Median length of hospital stay was 4 days in uncomplicated and 9 days in complicated cases. Based on costs of EUR 2500 per case, an attack rate of > 3 % in East African travelers and a cost of EUR 55 for a chemoprophylaxis with mefloquine, chemoprophylaxis is cost-effective. CONCLUSION In our retrospective analysis, complicated malaria tropica was associated with older age. Although malaria causes considerable morbidity, the overall mortality from severe malaria is low. Reinforcement of chemoprophylaxis especially in travelers to Africa could reduce malaria cases and is cost-effective.
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Affiliation(s)
- C Rabe
- Medizinische Klinik und Poliklinik I, Universitätskliniken Bonn.
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17
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Junghanss C, Waak M, Knopp A, Kleine HD, Kundt G, Leithäuser M, Hilgendorf I, Wolff D, Casper J, Freund M. Multivariate analyses of prognostic factors in acute myeloid leukemia: relevance of cytogenetic abnormalities and CD34 expression. Neoplasma 2005; 52:402-10. [PMID: 16151585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Identification of additional prognostic factors besides karyotype is important for the improvement of the risk adapted treatment strategies in acute myeloid leukemia (AML). The aim of this study was to investigate whether other factors besides karyotype could be used as a prognostic tool in newly diagnosed AML. Biological and disease related established and potential prognostic factors were retrospectively analysed in 124 consecutive AML patients treated between 1993 and 2002 at the University hospital Rostock (Germany). One hundred patients received a potential curative intensive chemotherapy (81%), of whom 28 received an allogeneic HSCT at some point of their treatment course, 17 patients (14%) received palliative therapies and 7 patients (5%) received supportive care only. In patients that received potential curative therapies LDH >or=2000 U/l, WBC >50 GPT/l, CD34 surface expression on the AML blasts, secondary AML, unfavorable karyotype and no allogeneic HSCT at some point of treatment course were associated with unfavorable prognosis. However, in the multivariate risk factor analyses only unfavorable karyotype (p=0.012), CD34 positivity of AML blasts (p=0.046), no allogeneic HSCT (p=0.008) and first diagnosis after 1997 (p=0.025) were independent unfavourable prognostic factors. In conclusion, karyotype and CD34 expression are independent prognostic markers in newly diagnosed AML. Furthermore, receiving an allogeneic HSCT at some point of the treatment course seems to be of benefit for AML patients.
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Affiliation(s)
- C Junghanss
- Department of Internal Medicine, Division of Hematology and Oncology, University of Rostock, 18057 Rostock, Germany.
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18
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Wolff D, Knopp A, Weirich V, Steiner B, Junghanss C, Casper J, Freund M. Loss of the GVL effect by loss of the Y-chromosome as putative mechanism of immune escape in ALL. Bone Marrow Transplant 2004; 35:101-2. [PMID: 15516938 DOI: 10.1038/sj.bmt.1704712] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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19
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Bollensdorff C, Knopp A, Biskup C, Zimmer T, Benndorf K. Na(+) current through KATP channels: consequences for Na(+) and K(+) fluxes during early myocardial ischemia. Am J Physiol Heart Circ Physiol 2004; 286:H283-95. [PMID: 12919930 DOI: 10.1152/ajpheart.00232.2003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During early myocardial ischemia, the myocytes are loaded with Na(+), which in turn leads to Ca(2+) overload and cell death. The pathway of the Na(+) influx has not been fully elucidated. The aim of the study was to quantify the Na(+) inward current through sarcolemmal KATP channels (IKATP,Na) in anoxic isolated cardiomyocytes at the actual reversal potential (Vrev) and to estimate the contribution of this current to the Na(+) influx in the ischemic myocardium. IKATP,Na was determined in excised single channel patches of mouse ventricular myocytes and macropatches of Xenopus laevis oocytes expressing SUR2A/Kir6.2 channels. In the presence of K+ ions, the respective permeability ratios for Na(+) to K(+) ions, PNa/PK, were close to 0.01. Only in the presence of Na(+) ions on both sides of the membrane was IKATP,Na similarly large to that calculated from the permeability ratio PNa/PK, indicative of a Na(+) influx that is largely independent of the K+ efflux at Vrev. With the use of a peak KATP channel conductance in anoxic cardiomyocytes of 410 nS, model simulations for a myocyte within the ischemic myocardium showed that the amplitude of the Na(+) influx and K(+) efflux is even larger than the respective fluxes by the Na(+) - K(+) pump and all other background fluxes. These results suggest that during early ischemia the Na(+) influx through KATP channels essentially contributes to the total Na+ influx and that it also balances the K(+) efflux through KATP channels.
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Affiliation(s)
- Christian Bollensdorff
- Institut für Physiologie, Friedrich-Schiller-Universität Jena, Teichgraben 8, D-07740 Jena, Germany
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20
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Kahl C, Knopp A, Steiner B, Leithäuser M, Wilhelm S, Kleine HD, Wolff D, Casper J, Freund M. Rare coincidence of hypertriploid chromosome number and aberrant coexpression of the lymphoid-associated antigen CD5 in acute myeloid Leukaemia FAB M0. Leukemia 2003; 17:1188-9. [PMID: 12764389 DOI: 10.1038/sj.leu.2402965] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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21
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Abstract
To examine the role of sarcolemmal K(ATP) channels in cardiac function, we generated transgenic mice expressing GFP-tagged Kir6.2 subunits with reduced ATP sensitivity under control of the cardiac alpha-myosin heavy chain promoter. Four founder mice were isolated, and both founders and progeny were all apparently normal and fertile. Electrocardiograms from conscious animals also appeared normal, although mean 24-hour heart rate was approximately 10% lower in transgenic animals compared with littermate controls. In excised membrane patches, K(ATP) channels were very insensitive to inhibitory ATP: mean K(1/2) ([ATP] causing half-maximal inhibition) was 2.7 mmol/L in high-expressing line 4 myocytes, compared with 51 micromol/L in littermate control myocytes. Counterintuitively, K(ATP) channel density was approximately 4-fold lower in transgenic membrane patches than in control. This reduction of total K(ATP) conductance was confirmed in whole-cell voltage-clamp conditions, in which K(ATP) was activated by metabolic inhibition. K(ATP) conductance was not obvious after break-in of either control or transgenic myocytes, and there was no action potential shortening in transgenic myocytes. In marked contrast to the effects of expression of similar transgenes in pancreatic beta-cells, these experiments demonstrate a profound tolerance for reduced ATP sensitivity of cardiac K(ATP) channels and highlight differential effects of channel activity in the electrical activity of the 2 tissues.
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Affiliation(s)
- J C Koster
- Department of Cell Biology, Washington University School of Medicine, St Louis, MO, USA
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22
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Knopp A, Thierfelder S, Doepner B, Benndorf K. Mitochondria are the main ATP source for a cytosolic pool controlling the activity of ATP-sensitive K(+) channels in mouse cardiac myocytes. Cardiovasc Res 2001; 52:236-45. [PMID: 11684071 DOI: 10.1016/s0008-6363(01)00395-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
OBJECTIVE The aim was to identify the major ATP source controlling the activity of sarcolemmal K(ATP) channels in ventricular cardiomyocytes. METHODS K(ATP)-channel current (I(KATP)) was measured with the patch-clamp technique in either the whole-cell (glycogenolysis blocked by 10 mmol/l EGTA), cell-attached, or inside-out configuration. RESULTS In the absence of any substrate, I(KATP) (amplitude 31+/-4 nA; n=5) appeared spontaneously 520+/-160 s (n=6) after whole-cell access. This latency was shortened by exposure to anoxia (117+/-33 s, n=32) and even more by uncoupling (1-10 micromol/l FCCP; 25+/-3 s; n=13) while the amplitude was unchanged. During metabolic inhibition the latency was remarkably prolonged when the F1F0-ATPase was blocked by oligomycin, suggesting that under those conditions the F1F0-ATPase is the major ATP consumer. Glucose (5.5-20.0 mmol/l) in the bath solution did not affect the amplitude of I(KATP) but prolonged its latency compared to respective substrate-free conditions. However, I(KATP) was blocked immediately by mitochondrial substrates. FCCP also induced large I(KATP) in cell-attached measurements in either the absence or presence of glucose and oligomycin. CONCLUSIONS The activity of K(ATP) channels in cardiomyocytes of mice is controlled by a cytosolic [ATP] pool for which oxidative phosphorylation is the predominant ATP source.
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Affiliation(s)
- A Knopp
- Institut für Physiologie, Abt. Herz-Kreislauf-Physiologie, Friedrich-Schiller-Universität Jena, D-07740, Jena, Germany
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23
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Abstract
A damaged nucleus has long been regarded simply as a "bag of broken chromosomes," with the DNA free ends moving around and forming connections with randomly encountered partners. Recent evidence shows this picture to be fundamentally wrong. Chromosomes occupy specific nuclear domains within which only limited movement is possible. In a human diploid nucleus, 6.6 x 10(9) base pairs (bp) of DNA are compartmentalized into chromosomes in a way that allows stringent control of replication, differential gene expression, recombination and repair. Most of the chromatin is further organized into looped domains by the dynamic binding of tethered bases to a network of intranuclear proteins, the so-called nuclear scaffold or matrix. Thus, DNA movement is severely curtailed, which limits the number of sites where interchanges can occur. This intricate organizational arrangement may render the genome vulnerable to processes that interfere with DNA repair. Both lower and higher eukaryotic cells perform homologous recombination (HR) and illegitimate recombination (IR) as part of their survival strategies. The repair processes comprising IR must be understood in the context of DNA structural organization, which is fundamentally different in prokaryotic and eukaryotic genomes. In this paper we first review important cellular processes including recombination, DNA repair, and apoptosis, and describe the central elements involved. Then we review the different DNA targets of recombination, and present recent evidence implicating the nuclear matrix in processes which can induce either repair, translocation, deletion, or apoptosis. J. Cell. Biochem. Suppl. 35:3-22, 2000.
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Affiliation(s)
- J Bode
- German Research Center for Biotechnology, Epigenetic Regulation, D-38124 Braunschweig, Mascheroder Weg 1, Germany.
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24
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Affiliation(s)
- T Muellner
- Department of Orthopaedic Surgery, Ulleval Hospital and Oslo University, Norway
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25
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Doepner B, Koopmann R, Knopp A, Hirche H, Benndorf K. Dibenzylamine--a novel blocker of the voltage-dependent K+ current in myocardial mouse cells. Naunyn Schmiedebergs Arch Pharmacol 2001; 364:9-13. [PMID: 11485044 DOI: 10.1007/s002100100406] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Ventricular myocytes of the mouse ventricle were voltage clamped with a patch-clamp technique in the whole-cell configuration. At depolarizing voltage pulses, these myocytes develop a large voltage-dependent K+ outward current. Application of the drug dibenzylamine (DBA) to the bath solution blocked the voltage-dependent K+ current. The concentration/response relationship for the peak current at +40 mV indicates a 1:1 binding of the drug to the receptor with a concentration of half maximum effect of 43.1 micromol/l. The block did not require activation of the channels by depolarizing pulses. At concentrations causing partial block (25 micromol/l), the block was independent of voltage. At the same concentration, DBA completely blocked the slow component of the recovery from inactivation (-80 mV) whereas steady-state inactivation was not altered. It is concluded that DBA is a novel blocker of the voltage-dependent K+ current in mouse cardiac myocytes which preferentially affects the current component generating the slow recovery from inactivation.
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Affiliation(s)
- B Doepner
- Institut für Physiologie der Friedrich-Schiller-Universität Jena, Abteilung Herz-Kreislauf-Physiologie, Germany
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26
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Junghanss C, Leithäuser M, Wilhelm S, Kleine HD, Knopp A, Decker S, Alscher A, Casper J, Köhne CH, Freund M. High-dose etoposide phosphate and G-CSF mobilizes peripheral blood stem cells in patients that previously failed to mobilize. Ann Hematol 2001; 80:96-102. [PMID: 11261332 DOI: 10.1007/s002770000235] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ten consecutive patients in our unit who had failed to mobilize a sufficient stem cell yield after either an initial or several mobilization regimens received high-dose etoposide phosphate (1500-2000 mg/m2) followed by granulocyte colony-stimulating factor (G-CSF; 10 micrograms/kg per day) to stimulate mobilization. Eight of the ten patients were apheresed. A median of 2.1 x 10(6) CD34+/kg (range 0-5.2) was collected. The number of CD34+ cells/microliter peripheral blood (pB) was significantly increased compared to the first-line mobilization [median 13.0 (range 2.68-29) versus median 4.76 (range 1.36-12); P < 0.05]. Besides hematotoxicity and four cases of infection (WHO grade 3), no major side effects were seen. The median duration of neutropenia was short (5 days, range 0-10), which is important in heavily pretreated patients. These results indicate that high-dose etoposide phosphate with G-CSF is safe, well tolerated, and may be effective in peripheral blood stem cell (PBSC) mobilization in patients who had previously failed to mobilize.
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Affiliation(s)
- C Junghanss
- Fred Hutchinson Cancer Research Center, Clinical Research Division, 1100 Fairview Avenue North, D1-100, PO Box 19024, Seattle, WA 98102-1024, USA.
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27
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Bode J, Benham C, Knopp A, Mielke C. Transcriptional augmentation: modulation of gene expression by scaffold/matrix-attached regions (S/MAR elements). Crit Rev Eukaryot Gene Expr 2000; 10:73-90. [PMID: 10813396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
For a long time S/MARs could only be characterized by the assays in vitro that led to their detection. Only recently a number of biological activities emerged that are common to most or all S/MARs that are detected by the classic procedures. This review focuses on the phenomenon of transcriptional augmentation that is found for genomically anchored or episomal genes and on a group of partially overlapping activities that are suited to maintain an episomal status. Further, it is attempted to correlate properties of the S/MAR-scaffold interaction with prominent or prototype protein binding partners.
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Affiliation(s)
- J Bode
- GBF, National Center for Biotechnological Research, Braunschweig
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28
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Abstract
OBJECTIVE The aim was to improve the measurement of both the time course and amplitude of anoxia-induced KATP-channel current (IKATP) in isolated heart cells to specify the role of these channels in the time course of K+ accumulation in the ischemic myocardium. METHODS Ionic currents in isolated ventricular heart cells of the mouse were measured with a patch clamp technique under normoxic conditions (atmospheric pO2), during wash-out of oxygen, and under anoxic conditions (pO2 < 0.2 mmHg). During the measurement, the actual pO2 in the close proximity of the cell was determined with an optical technique by exciting Pd-meso-tetra(4-carboxyphenyl)porphin with light flashes of 508-570 nm and evaluating the quenching kinetics of the emitted phosphorescence signal at 630-700 nm. These quenching kinetics steeply depend on pO2 and can be evaluated best at pO2 values near 0 mmHg. RESULTS Out of 28 cells, 23 cells started to develop IKATP at pO2 values between 0 and 0.4 mmHg, i.e. in the range of the level of half maximum activity of the cytochrome oxidase. The remaining five cells developed IKATP between 0.4 and 1.8 mmHg. With respect to the time course, 18 out of 27 cells started to develop IKATP within the first minute after pO2 had decreased to values below 0.2 mmHg. The amplitude of IKATP induced by anoxia and various metabolic inhibitors was large, 29 +/- 12 and 48 +/- 21 nA (+40 mV), respectively. The anoxia-induced IKATP was significantly smaller than IKATP induced by metabolic inhibitors. During the pulses of 50 ms duration to +40 mV, the amplitude of IKATP decayed and, after clamping back to -80 mV, IKATP generated large tail currents. This suggests a notable change in the concentration gradient of K+ ions in the time range of tens of milliseconds. CONCLUSIONS The results in isolated myocytes indicate that KATP channels open sufficiently rapidly after starting anoxia and generate sufficiently large conductance at maintained anoxia to explain both the time course and magnitude of the ischemic K+ accumulation if an appropriate counter-ion flux is available.
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Affiliation(s)
- A Knopp
- Institut für Physiologie, Abt. Herz-Kreislauf-Physiologie, Friedrich-Schiller-Universität Jena, Germany
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29
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Abstract
By use of microelectrodes, changes in the receptor current and the Ca2+ concentration were measured in the rod layer of the rat retina after stimulation by flashes or steady light. Thereby light induced Ca2+ sources, and sinks along a rod were determined in dependence of time. Thus, the Ca2+ fluxes across the plasma membrane of a mammalian rod could be studied in detail. By light stimulation, Ca2+ sources are evoked along the outer segment only. Immediately after a saturating flash, a maximum of Ca2+ efflux is observed which decays exponentially with tau = 0.3 s at 37 degrees C (4.2 s at 23 degrees C). During regeneration of the dark current, the outer segment acts as a Ca2+ sink, indicating a restoration of the Ca(2+)-depleted outer segment. These findings agree with earlier reports on amphibian rods. Further experiments showed that the peak Ca2+ efflux and tau are temperature dependent. The peak amplitude also depends on the external Ca2+ concentration. In contrast to the reports on amphibian rods, only a part of the Ca2+ ions extruded from the outer segment is directly restored. Surprisingly, during steady light the Ca2+ efflux approaches a permanent residual value. Therefore, in course of a photoresponse, Ca2+ must be liberated irreversibly from internal Ca2+ stores. There is certain evidence that the inner segment acts as a Ca2+ store. Our results show that the Ca2+ fraction of the ions carrying the dark current is proportional to the extracellular Ca2+ concentration. This indicates that the Ca2+ permeability of the plasma membrane of the rod outer segment is independent of the Ca2+ concentration.
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Affiliation(s)
- A Knopp
- Max Volmer Institut für Biophysikalische and Physikalische Chemie, Technische Universität Berlin, Germany
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30
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Abstract
Mechanical stress influences growth, differentiation, and gene expression in a variety of cell types. It is believed that via extracellular matrix the mechanical stimulus is transmitted to integrin receptors which thus play a key role in transducing signals into the cell interior. Here we demonstrate that incubation of suspended hepatocytes with specific antibodies to beta 1-integrin subunits followed by a short-term mechanical stimulation is sufficient to induce a rise in intracellular Ca2+. The results indicate that mechanical loading of individual integrin subunits activates Ca(2+)-specific signal pathways.
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Affiliation(s)
- B Nebe
- Department of Internal Medicine, University of Rostock, Germany
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31
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Henning W, Bohn W, Nebe B, Knopp A, Rychly J, Strauss M. Local increase of beta 1-integrin expression in cocultures of immortalized hepatocytes and sinusoidal endothelial cells. Eur J Cell Biol 1994; 65:189-99. [PMID: 7534233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The expression and spatial arrangement of beta 1-integrins was determined on two immortalized liver cell lines held in coculture, namely the epithelial cell line mHepR1 and a sinusoidal endothelial cell line. On mHepR1 cells the distribution of beta 1-integrins was restricted to the basolateral plasma membrane domains, a staining pattern that is typical of polarized epithelial cells. On the endothelial cell line the beta 1-integrins were distributed all over the cell surface. In coculture the endothelial cells tended to cover over the epithelial cells. Epithelial cells located in their vicinity exhibited an increased staining of beta 1-integrins at basolateral plasma membrane domains, which was most prominent with regard to the alpha 2-subunit. When mHepR1 cells were cultivated on various types of extracellular matrix also synthesized by the endothelial cells only collagen IV was found to increase the intensity of beta 1-integrin expression at the cell surface. The results indicate that beta 1-integrin expression in epithelial cell colonies can locally be modulated by interactions with non-parenchymal cells. In addition, the data suggest that mHepR1 cells may be a favorable system for analyzing basic functions of beta 1-integrins in polarized epithelial cells.
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Affiliation(s)
- W Henning
- Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie, Universität Hamburg, Germany
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Becker H, Knopp A. CD8+, CD3+, CD57+ lymphocytes in rheumatoid arthritis: comment on the article by Dupuy d'Angeac et al. Arthritis Rheum 1994; 37:302-4. [PMID: 7510490 DOI: 10.1002/art.1780370227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Becker H, Knopp A, Doppl W, Linn T, Becker F, Klör HU, Federlin K. [Increased activation of CD8-positive lymphocytes in patients with Crohn's disease]. Immun Infekt 1993; 21:5-8. [PMID: 8330894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
CD8+ (suppressor/cytotoxic) T lymphocyte subpopulations were studied in the peripheral blood of patients with Crohn's disease by flow cytometry analysis. Consistent with earlier reports, increased numbers of CD8+CD57+ cells were observed as compared with controls. However, expanded CD8+CD57+ cells were not found to be present in a distinct clinical subset of patients. A substantial number of patients had enhanced numbers of DR+ and CD45RO CD8+ cells. In addition, high numbers of CD8+ cells which were CD57CD45RO double positive, and a correlation between numbers of CD8+CD57+ and CD8+DR+ lymphocytes were detected. By use of an enzyme immunoassay, significantly elevated levels of soluble CD8 antigen were demonstrated in patients' sera, and results were associated with ESR values. Taken together, the data suggest increased activation of CD8+ lymphocytes which might result from systemic disease activity. Disturbances within CD8+ lymphocytes do not seem to be specific to Crohn's disease since similar alterations could be observed in patients with another inflammatory condition, rheumatoid arthritis.
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Affiliation(s)
- H Becker
- III. Medizinische Klinik und Poliklinik, Justus-Liebig-Universität Giessen
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Knopp MV, Schönhofen H, Knopp A. [A hepatic space-occupying lesion. Liver abscess due to a retained surgical towel]. Radiologe 1992; 32:451-2. [PMID: 1438732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- M V Knopp
- Deutsches Krebsforschungszentrum, Forschungsschwerpunkt Radiologische Diagnostik und Therapie, Heidelberg
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Löffler H, Knopp A, Krecke HJ. Cases of multiple myeloma (plasmacytoma) "without paraprotein". Ger Med Mon 1967; 12:226-9. [PMID: 6047332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Knopp A. [On the problem of diabetes diagnosis in life insurance]. Lebensversicher Med 1967; 19:12-5. [PMID: 4382852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Krück F, Krecke HJ, Knopp A. [The effect of an oral fluid load on the renal excretion of sodium in health and in hypertensive patients]. Klin Wochenschr 1966; 44:1349-55. [PMID: 5973249 DOI: 10.1007/bf01747894] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Löhr GW, Waller HD, Anschütz F, Knopp A. [Hexokinase deficiency in blood cells in a group of kin with familial panmyelopathy (Fanconi type)]. Klin Wochenschr 1965; 43:870-5. [PMID: 5862690 DOI: 10.1007/bf01711251] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Löhr GW, Waller HD, Anschütz F, Knopp A. [Biochemical defects in the blood cells in familial panmyelopathy (Fanconi type)]. Humangenetik 1965; 1:383-7. [PMID: 5869442 DOI: 10.1007/bf00273980] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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