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Vogginger B, Kreutz F, López-Randulfe J, Liu C, Dietrich R, Gonzalez HA, Scholz D, Reeb N, Auge D, Hille J, Arsalan M, Mirus F, Grassmann C, Knoll A, Mayr C. Automotive Radar Processing With Spiking Neural Networks: Concepts and Challenges. Front Neurosci 2022; 16:851774. [PMID: 35431782 PMCID: PMC9012531 DOI: 10.3389/fnins.2022.851774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/07/2022] [Indexed: 11/13/2022] Open
Abstract
Frequency-modulated continuous wave radar sensors play an essential role for assisted and autonomous driving as they are robust under all weather and light conditions. However, the rising number of transmitters and receivers for obtaining a higher angular resolution increases the cost for digital signal processing. One promising approach for energy-efficient signal processing is the usage of brain-inspired spiking neural networks (SNNs) implemented on neuromorphic hardware. In this article we perform a step-by-step analysis of automotive radar processing and argue how spiking neural networks could replace or complement the conventional processing. We provide SNN examples for two processing steps and evaluate their accuracy and computational efficiency. For radar target detection, an SNN with temporal coding is competitive to the conventional approach at a low compute overhead. Instead, our SNN for target classification achieves an accuracy close to a reference artificial neural network while requiring 200 times less operations. Finally, we discuss the specific requirements and challenges for SNN-based radar processing on neuromorphic hardware. This study proves the general applicability of SNNs for automotive radar processing and sustains the prospect of energy-efficient realizations in automated vehicles.
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Affiliation(s)
- Bernhard Vogginger
- Chair of Highly-Parallel VLSI-Systems and Neuro-Microelectronics, Faculty of Electrical and Computer Engineering, Institute of Principles of Electrical and Electronic Engineering, Technische Universität Dresden, Dresden, Germany
- *Correspondence: Bernhard Vogginger
| | - Felix Kreutz
- Chair of Highly-Parallel VLSI-Systems and Neuro-Microelectronics, Faculty of Electrical and Computer Engineering, Institute of Principles of Electrical and Electronic Engineering, Technische Universität Dresden, Dresden, Germany
- Infineon Technologies Dresden GmbH & Co., KG, Dresden, Germany
| | | | - Chen Liu
- Chair of Highly-Parallel VLSI-Systems and Neuro-Microelectronics, Faculty of Electrical and Computer Engineering, Institute of Principles of Electrical and Electronic Engineering, Technische Universität Dresden, Dresden, Germany
| | - Robin Dietrich
- Department of Informatics, Technical University of Munich, Munich, Germany
| | - Hector A. Gonzalez
- Chair of Highly-Parallel VLSI-Systems and Neuro-Microelectronics, Faculty of Electrical and Computer Engineering, Institute of Principles of Electrical and Electronic Engineering, Technische Universität Dresden, Dresden, Germany
| | - Daniel Scholz
- Chair of Highly-Parallel VLSI-Systems and Neuro-Microelectronics, Faculty of Electrical and Computer Engineering, Institute of Principles of Electrical and Electronic Engineering, Technische Universität Dresden, Dresden, Germany
- Infineon Technologies Dresden GmbH & Co., KG, Dresden, Germany
| | - Nico Reeb
- Department of Informatics, Technical University of Munich, Munich, Germany
| | - Daniel Auge
- Department of Informatics, Technical University of Munich, Munich, Germany
- Infineon Technologies AG, Munich, Germany
| | - Julian Hille
- Department of Informatics, Technical University of Munich, Munich, Germany
- Infineon Technologies AG, Munich, Germany
| | | | - Florian Mirus
- BMW Group, Research, New Technologies, Garching, Germany
| | | | - Alois Knoll
- Department of Informatics, Technical University of Munich, Munich, Germany
| | - Christian Mayr
- Chair of Highly-Parallel VLSI-Systems and Neuro-Microelectronics, Faculty of Electrical and Computer Engineering, Institute of Principles of Electrical and Electronic Engineering, Technische Universität Dresden, Dresden, Germany
- Centre for Tactile Internet (CeTI) With Human-In-The-Loop, Cluster of Excellence, Technische Universität Dresden, Dresden, Germany
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Abstract
AbstractBiologically inspired spiking neural networks are increasingly popular in the field of artificial intelligence due to their ability to solve complex problems while being power efficient. They do so by leveraging the timing of discrete spikes as main information carrier. Though, industrial applications are still lacking, partially because the question of how to encode incoming data into discrete spike events cannot be uniformly answered. In this paper, we summarise the signal encoding schemes presented in the literature and propose a uniform nomenclature to prevent the vague usage of ambiguous definitions. Therefore we survey both, the theoretical foundations as well as applications of the encoding schemes. This work provides a foundation in spiking signal encoding and gives an overview over different application-oriented implementations which utilise the schemes.
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Fahrmayr C, König J, Auge D, Mieth M, Münch K, Segrestaa J, Pfeifer T, Treiber A, Fromm M. Phase I and II metabolism and MRP2-mediated export of bosentan in a MDCKII-OATP1B1-CYP3A4-UGT1A1-MRP2 quadruple-transfected cell line. Br J Pharmacol 2014; 169:21-33. [PMID: 23387445 DOI: 10.1111/bph.12126] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 12/05/2012] [Accepted: 12/16/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Hepatic uptake (e.g. by OATP1B1), phase I and II metabolism (e.g. by CYP3A4, UGT1A1) and subsequent biliary excretion (e.g. by MRP2) are key determinants for the pharmacokinetics of numerous drugs. However, stably transfected cell models for the simultaneous investigation of transport and phase I and II metabolism of drugs are lacking. EXPERIMENTAL APPROACH A newly established quadruple-transfected MDCKII-OATP1B1-CYP3A4-UGT1A1-MRP2 cell line was used to investigate metabolism and transcellular transport of the endothelin receptor antagonist bosentan. KEY RESULTS Intracellular accumulation of bosentan equivalents (i.e. parent compound and metabolites) was significantly lower in all cell lines expressing MRP2 compared to cell lines lacking this transporter (P < 0.001). Accordingly, considerably higher amounts of bosentan equivalents were detectable in the apical compartments of cell lines with MRP2 expression (P < 0.001). HPLC and LC-MS measurements revealed that mainly unchanged bosentan accumulated in intracellular and apical compartments. Furthermore, the phase I metabolites Ro 48-5033 and Ro 47-8634 were detected intracellularly in cell lines expressing CYP3A4. Additionally, a direct glucuronide of bosentan could be identified intracellularly in cell lines expressing UGT1A1 and in the apical compartments of cell lines expressing UGT1A1 and MRP2. CONCLUSIONS AND IMPLICATIONS These in vitro data indicate that bosentan is a substrate of UGT1A1. Moreover, the efflux transporter MRP2 mediates export of bosentan and most likely also of bosentan glucuronide in the cell system. Taken together, cell lines simultaneously expressing transport proteins and metabolizing enzymes represent additional useful tools for the investigation of the interplay of transport and metabolism of drugs.
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Affiliation(s)
- C Fahrmayr
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
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Fahrmayr C, König J, Auge D, Mieth M, Fromm MF. Identification of drugs and drug metabolites as substrates of multidrug resistance protein 2 (MRP2) using triple-transfected MDCK-OATP1B1-UGT1A1-MRP2 cells. Br J Pharmacol 2012; 165:1836-1847. [PMID: 21923755 DOI: 10.1111/j.1476-5381.2011.01672.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The coordinate activity of hepatic uptake transporters [e.g. organic anion transporting polypeptide 1B1 (OATP1B1)], drug-metabolizing enzymes [e.g. UDP-glucuronosyltransferase 1A1 (UGT1A1)] and efflux pumps (e.g. MRP2) is a crucial determinant of drug disposition. However, limited data are available on transport of drugs (e.g. ezetimibe, etoposide) and their glucuronidated metabolites by human MRP2 in intact cell systems. EXPERIMENTAL APPROACH Using monolayers of newly established triple-transfected MDCK-OATP1B1-UGT1A1-MRP2 cells as well as MDCK control cells, single- (OATP1B1) and double-transfected (OATP1B1-UGT1A1, OATP1B1-MRP2) MDCK cells, we therefore studied intracellular concentrations and transcellular transport after administration of ezetimibe or etoposide to the basal compartment. KEY RESULTS Intracellular accumulation of ezetimibe was significantly lower in MDCK-OATP1B1-UGT1A1-MRP2 triple-transfected cells compared with all other cell lines. Considerably higher amounts of ezetimibe glucuronide were found in the apical compartment of MDCK-OATP1B1-UGT1A1-MRP2 monolayers compared with all other cell lines. Using HEK cells, etoposide was identified as a substrate of OATP1B1. Intracellular concentrations of etoposide equivalents (i.e. parent compound plus metabolites) were affected only to a minor extent by the absence or presence of OATP1B1/UGT1A1/MRP2. In contrast, apical accumulation of etoposide equivalents was significantly higher in monolayers of both cell lines expressing MRP2 (MDCK-OATP1B1-MRP2, MDCK-OATP1B1-UGT1A1-MRP2) compared with the single-transfected (OATP1B1) and the control cell line. CONCLUSIONS AND IMPLICATIONS Ezetimibe glucuronide is a substrate of human MRP2. Moreover, etoposide and possibly also its glucuronide are substrates of MRP2. These data demonstrate the functional interplay between transporter-mediated uptake, phase II metabolism and export by hepatic proteins involved in drug disposition.
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Affiliation(s)
- C Fahrmayr
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - J König
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - D Auge
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - M Mieth
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - M F Fromm
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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Kraft ME, Glaeser H, Mandery K, König J, Auge D, Fromm MF, Schlötzer-Schrehardt U, Welge-Lüssen U, Kruse FE, Zolk O. The prostaglandin transporter OATP2A1 is expressed in human ocular tissues and transports the antiglaucoma prostanoid latanoprost. Invest Ophthalmol Vis Sci 2009; 51:2504-11. [PMID: 20019365 DOI: 10.1167/iovs.09-4290] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Latanoprost, a prostaglandin F(2alpha) analogue, has become one of the most widely used medications for the treatment of glaucoma. The authors hypothesized that organic anion transporting polypeptides (OATPs) are responsible for the uptake of latanoprost into ocular tissues and, hence, that they contribute to the interindividual differences in drug concentrations and effects. METHODS Expression of prostaglandin (PG) transporters (OATP2A1, OATP2B1) in human ocular tissues was determined using real-time RT-PCR and immunofluorescence. The inhibitory interactions between latanoprost and its active metabolite (the free acid) and the uptake of prototypical substrates (PGE(2) and bromosulfophthalein) were tested in stably transfected human embryonic kidney cells overexpressing either OATP2A1 or OATP2B1. These cells were also used to investigate whether latanoprost and latanoprost acid are substrates of OATP2A1 or OATP2B1. RESULTS OATP2A1 and OATP2B1 mRNA expression was highest in the choroid/retinal pigment epithelium (RPE) complex and ciliary body. OATP2A1 protein expression was most prominent in the RPE and in epithelial and endothelial cell layers of anterior segment tissues, such as cornea, conjunctiva, iris, and ciliary body, whereas OATP2B1 protein was additionally expressed in trabecular meshwork, Schlemm canal, and choroidal vasculature. Latanoprost and latanoprost acid significantly inhibited both OATP2A1 and OATP2B1. Uptake experiments demonstrated that latanoprost acid is effectively transported by OATP2A1 (affinity constant [K(m)], 5.4 microM; maximum uptake rate [V(max)], 21.5 pmol/mg protein/min) and less effectively by OATP2B1. CONCLUSIONS The results presented herein suggest that at least OATP2A1 plays a role in the intraocular disposition of the therapeutically used prostanoid latanoprost.
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Affiliation(s)
- Michaela E Kraft
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen, Germany
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Seithel A, Eberl S, Singer K, Auge D, Heinkele G, Wolf NB, Dörje F, Fromm MF, König J. The influence of macrolide antibiotics on the uptake of organic anions and drugs mediated by OATP1B1 and OATP1B3. Drug Metab Dispos 2007; 35:779-86. [PMID: 17296622 DOI: 10.1124/dmd.106.014407] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [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: 12/14/2022] Open
Abstract
Macrolides may cause severe drug interactions due to the inhibition of metabolizing enzymes. Transporter-mediated uptake of drugs into cells [e.g., by members of the human organic anion transporting polypeptide (OATP) family] is a determinant of drug disposition and a prerequisite for subsequent metabolism. However whether macrolides are also inhibitors of uptake transporters, thereby providing an additional mechanism of drug interactions, has not been systematically studied. The human OATP family members OATP1B1 and OATP1B3 mediate the uptake of endogenous substances and drugs such as antibiotics and HMG-CoA reductase inhibitors (statins) into hepatocytes. In this study we investigated the potential role of these uptake transporters on macrolide-induced drug interactions. By using sulfobromophthalein (BSP) and the HMG-CoA reductase inhibitor pravastatin as substrates, the effects of the macrolides azithromycin, clarithromycin, erythromycin, and roxithromycin and of the ketolide telithromycin on the OATP1B1- and OATP1B3-mediated uptake were analyzed. These experiments demonstrated that the OATP1B1- and OATP1B3-mediated uptake of BSP and pravastatin can be inhibited by increasing concentrations of all macrolides except azithromycin. The IC50 values for the inhibition of OATP1B3-mediated BSP uptake were 11 microM for telithromycin, 32 microM for clarithromycin, 34 microM for erythromycin, and 37 microM for roxithromycin. These IC50 values were lower than the IC50 values for inhibition of OATP1B1-mediated BSP uptake (96-217 microM). These macrolides also inhibited in a concentration-dependent manner the OATP1B1- and OATP1B3-mediated uptake of pravastatin. In summary, these results indicate that alterations of uptake transporter function by certain macrolides/ketolides have to be considered as a potential additional mechanism underlying drug-drug interactions.
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Affiliation(s)
- Annick Seithel
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany
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Bachmakov I, Werner U, Endress B, Auge D, Fromm MF. Characterization of beta-adrenoceptor antagonists as substrates and inhibitors of the drug transporter P-glycoprotein. Fundam Clin Pharmacol 2006; 20:273-82. [PMID: 16671962 DOI: 10.1111/j.1472-8206.2006.00408.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [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: 01/11/2023]
Abstract
Transporter proteins such as P-glycoprotein are major determinants of intracellular drug concentrations. Moreover, inhibition or induction of transporters is an important mechanism underlying drug interactions in humans. However, very little is known whether beta-adrenoceptor antagonists are substrates and/or inhibitors of P-glycoprotein. Therefore, we investigated the P-glycoprotein-mediated transport of propranolol, metoprolol, bisoprolol, carvedilol and sotalol in P-glycoprotein-expressing Caco-2 monolayers and inhibition of P-glycoprotein-mediated digoxin transport by the beta-adrenoceptor antagonists. A significant inhibition of polarized, basal to apical drug transport by the P-glycoprotein inhibitor PSC-833 was observed for bisoprolol (0.5 and 5 microm) and carvedilol (0.5 microm). Moreover, propranolol and carvedilol inhibited P-glycoprotein-mediated digoxin transport with IC(50) values of 24.8 and 0.16 microm, respectively, whereas metoprolol and sotalol had no effect. Bisoprolol significantly inhibited directional digoxin transport at 50 and 250 microm by 31% and 44%, respectively. Taken together, P-glycoprotein is likely to be one determinant of bisoprolol and carvedilol disposition in humans. In addition, the beta-adrenoceptor antagonists propranolol and carvedilol significantly inhibit P-glycoprotein function thereby possibly contributing to drug interactions in humans (e.g. digoxin-carvedilol and cyclosporine-carvedilol).
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Affiliation(s)
- Iouri Bachmakov
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Erlangen-Nuremberg, Fahrstrasse 17, 91054 Erlangen, Germany
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Hinz B, Rau T, Auge D, Werner U, Ramer R, Rietbrock S, Brune K. Aceclofenac spares cyclooxygenase 1 as a result of limited but sustained biotransformation to diclofenac. Clin Pharmacol Ther 2003; 74:222-35. [PMID: 12966366 DOI: 10.1016/s0009-9236(03)00167-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [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: 11/27/2022]
Abstract
OBJECTIVE The mechanism of action of aceclofenac is currently unclear. This study investigated whether biotransformation to metabolites (4'-hydroxy-aceclofenac, diclofenac, 4'-hydroxy-diclofenac) contributes to inhibitory effects on the cyclooxygenase (COX) isozymes in vitro and ex vivo. METHODS In vitro investigations were performed with human whole blood and human blood monocytes. A randomized crossover study was performed in volunteers receiving 100 mg aceclofenac or a sustained-release resinate formulation of 75 mg diclofenac to assess the pharmacokinetics and the ex vivo inhibition of COX-1. RESULTS In short-term in vitro assays, neither aceclofenac nor 4'-hydroxy-aceclofenac affected COX-1 or COX-2, whereas diclofenac and 4'-hydroxy-diclofenac inhibited both isoforms. In long-term in vitro assays, aceclofenac and 4'-hydroxy-aceclofenac suppressed both COX isoforms. However, this inhibition was paralleled by a conversion to diclofenac and 4'-hydroxy-diclofenac, respectively. Maximal plasma concentrations of diclofenac after oral administration of aceclofenac (0.39 micromol/L) or diclofenac (1.28 micromol/L) were sufficient for a greater than 97% inhibition of COX-2 (50% inhibitory concentration, 0.024 micromol/L) and a 46% (aceclofenac treatment) or 82% inhibition (diclofenac treatment) of COX-1 (50% inhibitory concentration, 0.43 micromol/L). Moreover, ex vivo COX-1-dependent thromboxane B(2) synthesis was inhibited significantly less by aceclofenac than by diclofenac. CONCLUSIONS Inhibition of COX isozymes by aceclofenac requires conversion into diclofenac. Although 100 mg aceclofenac yielded diclofenac concentrations substantially lower than 75 mg diclofenac, these were sufficient for a sustained block of COX-2 but caused a minor and shorter inhibition of COX-1 than 75 mg diclofenac. In conclusion, both COX-1-sparing and COX-2-inhibitory actions of aceclofenac may rest in its limited but sustained biotransformation to diclofenac.
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Affiliation(s)
- Burkhard Hinz
- Department of Experimental and Clinical Pharmacology and Toxicology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany.
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Hinz B, Auge D, Rau T, Rietbrock S, Brune K, Werner U. Simultaneous determination of aceclofenac and three of its metabolites in human plasma by high-performance liquid chromatography. Biomed Chromatogr 2003; 17:268-75. [PMID: 12833392 DOI: 10.1002/bmc.243] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [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: 11/12/2022]
Abstract
Aceclofenac [[2-(2',6'-dichlorophenyl)amino]phenylacetoxyacetic acid] is a phenylacetic acid derivative with potent analgesic and anti-inflammatory properties and an improved gastro-intestinal tolerance. In the present study, a liquid-liquid extraction-based reversed-phase HPLC method with UV detection was validated and applied for the analysis of aceclofenac and three of its metabolites (4'-hydroxy-aceclofenac, diclofenac, 4'-hydroxy-diclofenac) in human plasma. The analytes were separated using an acetonitrile-phosphate buffer gradient at a flow rate of 1 mL/min, and UV detection at 282 nm. The retention times for aceclofenac, diclofenac, 4'-hydroxy-aceclofenac, 4'-hydroxy-diclofenac and ketoprofen (internal standard) were 69.1, 60.9, 46.9, 28.4 and 21.2 min, respectively. The validated quantitation range of the method was 10-10000 ng/mL for aceclofenac, 4'-hydroxy-aceclofenac and diclofenac, and 25-10000 ng/mL for 4'-hydroxy-diclofenac. The developed procedure was applied to assess the pharmacokinetics of aceclofenac and its metabolites following administration of a single 100 mg oral dose of aceclofenac to three healthy male volunteers.
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Affiliation(s)
- Burkhard Hinz
- Department of Experimental and Clinical Pharmacology and Toxicology, Friedrich Alexander University Erlangen-Nürnberg, Fahrstrasse 17, D-91054 Erlangen, Germany.
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Auge D, Georg R. Intrathoracic meningocele. J Thorac Cardiovasc Surg 1993; 105:561-2. [PMID: 8445940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Auge D, Goerg R. [Histiocytosis X]. Dtsch Med Wochenschr 1992; 117:518. [PMID: 1551379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Andreas S, Hajak G, Natt P, Auge D, Rüther E, Kreuzer H. [ST segmental changes and arrhythmias in obstructive sleep apnea]. Pneumologie 1991; 45:720-4. [PMID: 1946265] [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: 12/29/2022]
Abstract
Patients with obstructive sleep apnea show a fall in arterial oxygen saturation during apneas. Whether this is causing myocardial ischemia and consecutively ST segment depressions in the electrocardiogram is not known. Therefore 15 consecutive patients (53 +/- 8 years, apnea index 45 +/- 28, minimal oxygen saturation 71 +/- 14%) with OSA were studied by Holter electrocardiogram and polysomnography. History and exercise testing gave no evidence of coronary heart disease. Three patients had ventricular arrhythmias Lown IVA and 10 had Lown I or III. Three patients showed unspecific negative T waves or ST segment elevations. In no patient significant ST segment depression was found. It is concluded that OSA does not lead to ischemic ST segment depression in the absence of coronary heart disease. The cause of ventricular arrhythmias in OSA seems not be related to myocardial ischemia.
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Affiliation(s)
- S Andreas
- Abteilung für Kardiologie und Pneumologie, Universität Göttingen
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Auge D, Goerg R, Laberke HG. [Pulmonary histiocytosis X]. Pneumologie 1991; 45:616-21. [PMID: 1946259] [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: 12/29/2022]
Abstract
This is a report on 2 adult patients suffering from pulmonary histiocytosis X. The aetiology and the diagnostic and therapeutic approach are discussed on the basis of a review of the literature. This is a rare disease that is triggered by a virus and immunologically conditioned, the disposition being genetically transferred. It is characterised by cells known as histiocytosis X cells with typical X bodies and immunocytochemically identifiable S 100 antigen. It will usually be necessary to perform an open biopsy of the lung to determine the histology of histiocytosis X. Roentgenologically pathognomonic signs are in particular ring-shaped structures of up to 5 mm diameter with a marginal edge. Lung function analysis revealing hypoxaemia after stress and, less significantly, diffusion capacity and vital capacity, are also among the most sensitive data pointing to histiocytosis X. Indication for treating the patients, who usually do not display prominent signs and symptoms, should be discrete because spontaneous remissions occur very frequently. If the patients display relevant signs and symptoms, corticosteroid long-term treatment over 12 months with 0.5-1.0 mg/kg body weight per day is recommended employing a slowly and progressively reduced dosage schedule. Chemotherapeutic drugs or thymus extracts are administered in a few rare instances.
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Affiliation(s)
- D Auge
- Abteilung Kardiologie und Pulmonologie, Universität Göttingen
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