39 results on '"T. Huber"'
Search Results
2. Coronary CT FFR vs Invasive Adenosine and Dobutamine FFR in a Right Anomalous Coronary Artery
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Marius R. Bigler, Anselm W. Stark, Andreas A. Giannopoulos, Adrian T. Huber, Matthias Siepe, Alexander Kadner, Lorenz Räber, Christoph Gräni, University of Zurich, and Gräni, Christoph
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610 Medicine & health ,10181 Clinic for Nuclear Medicine ,Cardiology and Cardiovascular Medicine ,2705 Cardiology and Cardiovascular Medicine - Abstract
We present the management of an anomalous coronary artery originating from the opposite sinus of Valsalva with comprehensive diagnostic workup including noninvasive coronary computed tomography (CT) derived fractional flow reserve (FFR) and invasive dobutamine-volume challenge-FFR/intravascular ultrasound. After surgical operation, treatment success was quantified by anatomical and functional analysis in postoperative CT. (Level of Difficulty: Advanced.).
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- 2022
3. Reproducibility of 4D cardiac computed tomography feature tracking myocardial strain and comparison against speckle-tracking echocardiography in patients with severe aortic stenosis
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Benedikt Bernhard, Hanna Grogg, Jan Zurkirchen, Caglayan Demirel, Daniel Hagemeyer, Taishi Okuno, Nicolas Brugger, Stefano De Marchi, Adrian T. Huber, Martina Boscolo Berto, Giancarlo Spano, Stefan Stortecky, Stephan Windecker, Thomas Pilgrim, and Christoph Gräni
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Male ,endocrine system ,Computed Tomography Angiography ,Reproducibility of Results ,610 Medicine & health ,Aortic Valve Stenosis ,Ventricular Function, Left ,Echocardiography ,Predictive Value of Tests ,Humans ,Radiology, Nuclear Medicine and imaging ,Female ,Cardiology and Cardiovascular Medicine ,Retrospective Studies - Abstract
BACKGROUND Myocardial strain is an established parameter for the assessment of cardiac function and routinely derived from speckle tracking echocardiography (STE). Novel post-processing tools allow deformation imaging also by 4D cardiac computed tomography angiography (CCT). This retrospective study aims to analyze the reproducibility of CCT strain and compare it to that of STE. METHODS Left (LV) and right ventricular (RV), and left atrial (LA) ejection fraction (EF), dimensions, global longitudinal (GLS), circumferential (GCS) and radial strain (GRS) were determined by STE and CCT feature tracking in consecutive patients with severe aortic stenosis evaluated for transcatheter aortic valve implantation. RESULTS 106 patients (mean age 79.9������������7.8, 44.3% females) underwent CCT at a median of 3 days (IQR 0-28 days) after STE. In CCT, strain measures showed good to excellent reproducibility (intra- and inter-reader intraclass correlation coefficient ���0.75) consistently in the LV, RV and LA. In STE, only LV GLS and LA GLS yielded good reproducibility, whereas LV GCS and LV GRS showed moderate, and RV GLS and free wall longitudinal strain (FWLS) poor reproducibility. Agreement between CCT and STE was strong for LV GLS only, while other strain features displayed moderate (LV GCS, LA GLS) or weak (LV GRS, RV GLS and FWLS) inter-modality correlation. CONCLUSION LV, RV and LA CCT strain assessments were highly reproducible. While a strong agreement to STE was found for LV GLS, inter-modality correlation was moderate or weak for LV GCS, LV GRS, and RV and LA longitudinal strain, possibly related to poor reproducibility of STE measurements.
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- 2022
4. Cretaceous Climate
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Brian T. Huber and Charlotte L. O’Brien
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- 2021
5. Application of two stage turbocharging systems on large engines
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E. Codan and T. Huber
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Engineering ,business.industry ,Engine efficiency ,Systems design ,Stage (hydrology) ,business ,Automotive engineering ,Turbocharger ,Envelope (motion) - Abstract
The first applications of 2-stage turbocharging on large engines are already in operation (1), (2). The main drivers for the introduction of this technology are power density, engine efficiency and low emissions. In this paper some aspects and requirements of engine and turbocharging system design are discussed. Furthermore, some results of detailed studies for the different engine segments are presented. Engine size, operational envelope and performance requirements influence both the design parameters of the system and its development potential. Emissions represent a further challenge for large engines; the contributions of the turbocharging system are discussed.
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- 2012
6. Rhodopsin
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T.P. Sakmar and T. Huber
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- 2009
7. Design, Manufacturing and Testing of the W7-X Target Element Prototypes
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E. Parteder, H. Greuner, T. Huber, H. Renner, J. Kisslinger, and L. Plöchl
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Materials science ,Power load ,Braze alloy ,Divertor ,Mechanical engineering ,Brazing ,Water pressure ,Joint (geology) ,Finite element method ,Corrosion - Abstract
The W7X divertor consists of 10 units with a 3D target area of 22 m2, which is approximated by flat target elements (dimensions: 50 mm width and 200 to 500 mm length) being capable of a power load of up to 10 MW/m2. Four prototype target elements were designed, manufactured and partially tested in the JUDITH facility (KFA Julich), successfully. The design was based on a FEM analysis of the brazing constraints and a J-integral analysis of the braze joint: Even large braze flaws, resulting from a lack of braze alloy or water corrosion, will not critically grow and lead to catastrophic interface failure under the brazing constraints and the water pressure.
- Published
- 1997
8. Predictive value of cardiac magnetic resonance right ventricular longitudinal strain in patients with suspected myocarditis
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Benedikt Bernhard, Giulin Tanner, Davide Garachemani, Aaron Schnyder, Kady Fischer, Adrian T. Huber, Yasaman Safarkhanlo, Anselm W. Stark, Dominik P. Guensch, Jonathan Schütze, Simon Greulich, Jessica A. M. Bastiaansen, Maryam Pavlicek-Bahlo, Dominik C. Benz, Raymond Y. Kwong, and Christoph Gräni
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Myocarditis ,Right ventricle ,Cardiac magnetic resonance imaging ,Feature tracking ,Right ventricular global longitudinal strain ,Heart failure hospitalizations ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Abstract Background Recent evidence underlined the importance of right (RV) involvement in suspected myocarditis. We aim to analyze the possible incremental prognostic value from RV global longitudinal strain (GLS) by CMR. Methods Patients referred for CMR, meeting clinical criteria for suspected myocarditis and no other cardiomyopathy were enrolled in a dual-center register cohort study. Ejection fraction (EF), GLS and tissue characteristics were assessed in both ventricles to assess their association to first major adverse cardiovascular events (MACE) including hospitalization for heart failure (HF), ventricular tachycardia (VT), recurrent myocarditis and death. Results Among 659 patients (62.8% male; 48.1 ± 16.1 years), RV GLS was impaired (> − 15.4%) in 144 (21.9%) individuals, of whom 76 (58%), 108 (77.1%), 27 (18.8%) and 40 (32.8%) had impaired right ventricular ejection fraction (RVEF), impaired left ventricular ejection fraction (LVEF), RV late gadolinium enhancement (LGE) or RV edema, respectively. After a median observation time of 3.7 years, 45 (6.8%) patients were hospitalized for HF, 42 (6.4%) patients died, 33 (5%) developed VT and 16 (2.4%) had recurrent myocarditis. Impaired RV GLS was associated with MACE (HR = 1.07, 95% CI 1.04–1.10; p
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- 2023
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9. Non-invasive differentiation of idiopathic inflammatory myopathy with cardiac involvement from acute viral myocarditis using cardiovascular magnetic resonance imaging T1 and T2 mapping
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Adrian T. Huber, Marine Bravetti, Jérôme Lamy, Tania Bacoyannis, Charles Roux, Alain de Cesare, Aude Rigolet, Olivier Benveniste, Yves Allenbach, Mathieu Kerneis, Philippe Cluzel, Nadjia Kachenoura, and Alban Redheuil
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Cardiac inflammation ,Systemic myositis ,CMR T1/T2 mapping ,Extracellular volume ,Skeletal muscle ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Abstract Background Idiopathic inflammatory myopathy (IIM) is a group of autoimmune diseases with systemic myositis which may involve the myocardium. Cardiac involvement in IIM, although often subclinical, may mimic clinical manifestations of acute viral myocarditis (AVM). Our aim was to investigate the usefulness of the combined analysis of cardiovascular magnetic resonance (CMR) T1 and T2 mapping parameters measured both in the myocardium and in the thoracic skeletal muscles to differentiate AVM from IIM cardiac involvement. Methods Sixty subjects were included in this retrospective study (36 male, age 45 ± 16 years): twenty patients with AVM, twenty patients with IIM and cardiac involvement and twenty healthy controls. Study participants underwent CMR imaging with modified Look-Locker inversion-recovery (MOLLI) T1 mapping and 3-point balanced steady-state-free precession T2 mapping. Relaxation times were quantified after endocardial and epicardial delineation on basal and medial short-axis slices, as well as in different thoracic skeletal muscle groups present in the CMR field-of-view. ROC-Analysis was performed to assess the ability of mapping indices to discriminate the study groups. Results Mapping parameters in the thoracic skeletal muscles were able to discriminate between AVM and IIM patients. Best skeletal muscle parameters to identify IIM from AVM patients were reduced post-contrast T1 and increased extracellular volume (ECV), resulting in an area under the ROC curve (AUC) of 0.95 for post-contrast T1 and 0.96 for ECV. Conversely, myocardial mapping parameters did not discriminate IIM from AVM patients but increased native T1 (AUC 0.89 for AVM; 0.84 for IIM) and increased T2 (AUC 0.82 for AVM; 0.88 for IIM) could differentiate both patient groups from healthy controls. Conclusion CMR myocardial mapping detects cardiac inflammation in AVM and IIM compared to normal myocardium in healthy controls but does not differentiate IIM from AVM. However, thoracic skeletal muscle mapping was able to accurately discern IIM from AVM.
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- 2018
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10. Alterations of plasma lipids in mice via adenoviral-mediated hepatic overexpression of human ABCA1
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Cheryl L. Wellington, Liam R. Brunham, Steven Zhou, Roshni R. Singaraja, Henk Visscher, Allison Gelfer, Colin Ross, Erick James, Guoqing Liu, Mary T. Huber, Yu-Zhou Yang, Robin J. Parks, Albert Groen, Jamila Fruchart-Najib, and Michael R. Hayden
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ATP binding cassette transporter A1 ,HDL cholesterol ,adenovirus ,bacterial artificial chromosome transgenic ,hepatocytes ,regulation ,Biochemistry ,QD415-436 - Abstract
ATP binding cassette transporter A1 (ABCA1) is a widely expressed lipid transporter essential for the generation of HDL. ABCA1 is particularly abundant in the liver, suggesting that the liver may play a major role in HDL homeostasis. To determine how hepatic ABCA1 affects plasma HDL cholesterol levels, we treated mice with an adenovirus (Ad)-expressing human ABCA1 under the control of the cytomegalovirus promoter. Treated mice showed a dose-dependent increase in hepatic ABCA1 protein, ranging from 1.2-fold to 8.3-fold using doses from 5 × 108 to 1.5 × 109 pfu, with maximal expression observed on Day 3 posttreatment. A selective increase in HDL cholesterol occurred at Day 3 in mice treated with 5 × 108 pfu Ad-ABCA1, but higher doses did not further elevate HDL cholesterol levels. In contrast, total cholesterol, triglycerides, phospholipids, non-HDL cholesterol, and apolipoprotein B levels all increased in a dose-dependent manner, suggesting that excessive overexpression of hepatic ABCA1 in the absence of its normal regulatory sequences altered total lipid homeostasis. At comparable expression levels, bacterial artificial chromosome transgenic mice, which express ABCA1 under the control of its endogenous regulatory sequences, showed a greater and more specific increase in HDL cholesterol than Ad-ABCA1-treated mice.Our results suggest that appropriate regulation of ABCA1 is critical for a selective increase in HDL cholesterol levels.
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- 2003
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11. Severe Hyperthermia in Mountaineering: Coincidence of Heat Stroke and Infection.
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Huber T, Egger A, and Heschl S
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- Humans, Female, Austria, Hyperthermia etiology, Middle Aged, Adult, Fever etiology, Mountaineering, Heat Stroke complications, Heat Stroke etiology
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Heat illness is a condition that is sometimes seen in those undertaking physical activities. This case report focuses on a female hiker who developed heat stroke during a trek in the Dachstein region of Upper Austria. The patient's presentation was initially unclear and could only be confirmed by the use of a thermometer. This had a significant impact on the medical decision-making process during a complex rescue operation.
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- 2024
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12. The impact of fractionation on secondary malignancies in postoperative breast cancer irradiation.
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Kiesl S, Düsberg M, Behzadi ST, Moser R, Nano J, Huber T, Klein E, Kiechle M, Bernhardt D, Combs SE, and Borm KJ
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- Humans, Female, Middle Aged, Radiation Dose Hypofractionation, Radiotherapy, Adjuvant adverse effects, Aged, Dose Fractionation, Radiation, Neoplasms, Radiation-Induced etiology, Radiotherapy, Intensity-Modulated adverse effects, Radiotherapy, Intensity-Modulated methods, Adult, Lung Neoplasms radiotherapy, Unilateral Breast Neoplasms radiotherapy, Unilateral Breast Neoplasms surgery, Radiotherapy, Conformal adverse effects, Radiotherapy, Conformal methods, Mastectomy, Neoplasms, Second Primary etiology, Breast Neoplasms radiotherapy, Breast Neoplasms surgery
- Abstract
Purpose: Randomized studies demonstrated the oncological equivalence of (ultra-)hypofractionation compared to a 5-week schedule in postoperative radiotherapy of breast cancer. Due to the low incidence and long latency of secondary malignancies, there are currently no reliable clinical data regarding the influence of fractionation regimens on the development of secondary malignancies., Material and Methods: For 20 patients with right or left-sided breast cancer, postoperative treatment plans were created using 3D-CRT (n = 10) or VMAT (n = 10) for three different fractionation schedules: 5-week schedule with 50.4Gy in 1.8Gy (28fx), hypofractionation with 40.05Gy in 2.67Gy (15fx) and ultra-hypofractionation with 26Gy in 5.2Gy (5fx). The EARs (absolute additional cases of disease per 10,000 patient-years) for secondary malignancies in the lung, contralateral breast, esophagus, liver, thyroid, spinal cord, bones and soft tissue were calculated using a fraction-dependent dose-response model., Results: Based on risk modulation, (ultra-)hypofractionation resulted in significantly lower EARs for lung cancer (LC), contralateral breast cancer (CBC) and soft tissue sarcoma (STS) (p < .001). For the ultra-hypofractionated dose concept the median EARs for LC, CBC and STS were 42.8 %, 39.4 % and 58.1 % lower compared to conventional fractionation and 31.2 %, 25.7 % and 20.3 % compared to hypofractionation. The influence of fractionation on the risk of secondary malignancies for LC and CBC was less pronounced with 3D-CRT than with VMAT. For STS, however, the influence of fractionation was greater with 3D-CRT than with VMAT., Conclusion: Based on this simulation study (ultra-)hypofractionated postoperative breast cancer irradiation may be associated with a lower risk of secondary malignancies compared to a 5-week schedule., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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13. Application of bioluminescence resonance energy transfer to quantitate cell-surface expression of membrane proteins.
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Mattheisen JM, Rasmussen VA, Ceraudo E, Kolodzinski A, Horioka-Duplix M, Sakmar TP, and Huber T
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- Cell Membrane metabolism, Fluorescence Resonance Energy Transfer, Bioluminescence Resonance Energy Transfer Techniques, Membrane Proteins, Receptors, G-Protein-Coupled
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We report a bioluminescence resonance energy transfer (BRET) assay to quantitate the fraction of an engineered membrane protein at the cell surface versus inside the cell. As test cases, we engineered two different G protein-coupled receptors (GPCRs) in which a NanoLuc luciferase (NLuc) and a HaloTag are fused to the extracellular amino-terminal tail of the receptors. We then employed a pulse-chase labeling approach relying on two different fluorescent dyes with distinctive cell permeability properties. The dyes are efficiently excited by luminescence from NLuc, but are spectrally distinct. Measuring BRET from the chemiluminescence of the NLuc to the fluorophores bound to the HaloTag minimizes the limitations of in-cell fluorescence resonance energy transfer (FRET)-based approaches such as photobleaching and autofluorescence. The BRET surface expression assay can quantitatively differentiate between the labeling of receptors at the cell surface and receptors inside of the cell. The assay is shown to be quantitative and robust compared with other approaches to measure cell surface expression of membrane proteins such as enzyme-linked immunosorbent assay or immunoblotting, and significantly increases the throughput because the assay is designed to be carried out in microtiter plate format., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)
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- 2024
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14. Education Team Time Out in Oncologic Visceral Surgery Optimizes Surgical Resident Training and Team Communication-Results of a Prospective Trial.
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Huber T, Boedecker C, Borchardt T, Vradelis L, Wachter N, Grimminger PP, Musholt TJ, Mädge S, Griemert EV, Heinrich S, Huettl F, and Lang H
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- Humans, Prospective Studies, Curriculum, Communication, Internship and Residency, Digestive System Surgical Procedures
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Background: Surgical education is highly dependent on intraoperative communication. Trainers must know the trainee's training level to ensure high-quality surgical training. A systematic preoperative dialogue (Educational Team Time Out, ETO) was established to discuss the steps of each surgical procedure., Methods: Over 6 months, ETO was performed within a time limit of 3 minutes. Digital surveys on the utility of ETO and its impact on performance were conducted immediately after surgery and at the end of the study period among the staff of the participating disciplines (trainer, trainee, surgical nursing staff, anaesthesiologists, and medical students). The number of surgical substeps performed was recorded and compared with the equivalent period one year earlier., Results: ETO was performed in 64 of the 103 eligible operations (62%). Liver resection (n = 37) was the most frequent procedure, followed by left-sided colorectal surgery (n = 12), partial pancreaticoduodenectomy (n = 6), right-sided hemicolectomies (n = 5), and thyroidectomies (n = 4). Anaesthesiologists most frequently reported that ETO had a direct impact on their work during surgery (90.9%). The influence scores were 46.8% for trainees, 8.8% for trainers, 53.3% for surgical nursing staff and 66.6% for medical students. During the implementation of ETO, a trend towards more assisted substeps in oncologic visceral surgery was seen compared to the corresponding period one year earlier (51% vs.40%; p = 0.11)., Conclusion: ETO leads to improved intraoperative communication and more performed substeps during complex procedures, which increases motivation and practical training. This concept can easily be implemented in all surgical specialties to improve surgical education., (Copyright © 2023 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.)
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- 2023
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15. Misdiagnosis of Thoracic Aortic Disease Occurs Commonly in Emergency Transfers.
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Holmes HR, Neal D, Freeman K, Jeng E, Back M, Huber T, Arnaoutakis KD, Shah S, Upchurch GR Jr, Cooper M, Beaver TM, Martin TD, and Arnaoutakis GJ
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- Male, Humans, Middle Aged, Female, Retrospective Studies, Aorta, Diagnostic Errors, Acute Disease, Aortic Dissection diagnosis, Aortic Dissection surgery, Aortic Aneurysm, Thoracic diagnosis, Aortic Aneurysm, Thoracic surgery, Aortic Diseases, Thoracic Diseases, Aortic Rupture
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Background: Acute aortic syndromes (AASs) are prone to misdiagnosis by facilities with limited diagnostic experience. We assessed long-term trends in misdiagnosis among patients transferred to a tertiary care facility with presumed AASs., Methods: Our institutional transfer center database was queried for emergency transfers in patients with a diagnosis of AASs or thoracic aortic aneurysm between January 2008 and May 2018. There were 784 patients classified as emergency transfer for presumed AAS. Transferring diagnosis and actual diagnosis were compared through a review of physician notes and radiology reports from referring facilities and our center., Results: Mean age was 62 years, with 478 (61%) men. Differences in transferring diagnosis and actual diagnosis were identified in 89 patients (11.4%). Among misdiagnosed patients, the wrong classification of Stanford type A or type B dissections was identified among 24 patients (27%). No dissection was found in 23 patients (26%) with a referring diagnosis of aortic dissection. No signs of rupture were found in 18 patients (20%) transferred for contained/impending rupture. All misdiagnoses were secondary to misinterpretation of radiographic imaging, with motion artifacts in 14 (16%) and postsurgical changes in 22 (25%) being common sources of diagnostic error. Repeat scans were performed in 64 patients (72%) at our facility due to limited access to or suboptimal quality of outside imaging., Conclusions: Although AASs misdiagnosis rates appear to be improving from the prior decade, there are opportunities for improved physician awareness through campaigns such as "Think Aorta." Centralized web-based imaging may prevent the costly hazards of unnecessary emergency transfer., (Copyright © 2022 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)
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- 2022
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16. Prostatic Artery Embolization for Treatment of Lower Urinary Tract Symptoms: A Markov Model-Based Cost-Effectiveness Analysis.
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Rink JS, Froelich MF, McWilliams JP, Gratzke C, Huber T, Gresser E, Schoenberg SO, Diehl SJ, and Nörenberg D
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- Arteries, Cost-Benefit Analysis, Humans, Male, Prostate blood supply, Prostate surgery, Treatment Outcome, Embolization, Therapeutic, Lower Urinary Tract Symptoms etiology, Lower Urinary Tract Symptoms therapy, Prostatic Hyperplasia complications, Prostatic Hyperplasia therapy, Transurethral Resection of Prostate adverse effects, Transurethral Resection of Prostate methods
- Abstract
Purpose: The aim of this study was to investigate whether prostatic artery embolization (PAE) can be considered a long-term cost-effective treatment option in patients with lower urinary tract symptoms secondary to benign prostatic hyperplasia in comparison to transurethral resection of the prostate (TURP)., Methods: The in-hospital costs of PAE and TURP in the United States were obtained from a recent cost analysis. Clinical outcomes including nature and rate of adverse events for TURP and PAE along with rates of retreatment because of complications or clinical failure were obtained from peer-reviewed literature. A decision tree-based Markov model was created, analyzing long-term cost-effectiveness for TURP and PAE from a US health care sector perspective. Cost-effectiveness over a time frame of 5 years was estimated while assuming a willingness to pay of $50,000 per quality-adjusted life-year (QALY). The primary outcome was incremental cost-effectiveness ratio., Results: PAE resulted in overall cost of $6,464.92 and an expected outcome of 4.566 QALYs. In comparison, TURP cost $9,221.09 and resulted in expected outcome of 4.577 QALYs per treatment. The incremental cost-effectiveness ratio for TURP was $247,732.65 per QALY. On the basis of the willingness-to-pay threshold, PAE is cost effective compared with TURP., Conclusions: On the basis of our model, PAE in comparison with TURP can be regarded as a cost-effective treatment option for patients with lower urinary tract symptoms within the US health care system., (Copyright © 2022 American College of Radiology. Published by Elsevier Inc. All rights reserved.)
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- 2022
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17. A comparison of input devices for precise interaction tasks in VR-based surgical planning and training.
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Allgaier M, Chheang V, Saalfeld P, Apilla V, Huber T, Huettl F, Neyazi B, Sandalcioglu IE, Hansen C, Preim B, and Saalfeld S
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- Humans, Virtual Reality
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To exploit the potential of virtual reality (VR) in medicine, the input devices must be selected carefully due to their different benefits. In this work, input devices for common interaction tasks in medical VR planning and training are compared. Depending on the specific purpose, different requirements exist. Therefore, an appropriate trade-off between meeting task-specific requirements and having a widely applicable device has to be found. We focus on two medical use cases, liver surgery planning and craniotomy training, to cover a broad medical domain. Based on these, relevant input devices are compared with respect to their suitability for performing precise VR interaction tasks. The devices are standard VR controllers, a pen-like VR Ink, data gloves and a real craniotome, the medical instrument used for craniotomy. The input devices were quantitatively compared with respect to their performance based on different measurements. The controllers and VR Ink performed significantly better than the remaining two devices regarding precision. Qualitative data concerning task load, cybersickness, and usability and appropriateness of the devices were assessed. Although no device stands out for both applications, most participants preferred using the VR Ink, followed by the controller and finally the data gloves and craniotome. These results can guide the selection of an appropriate device for future medical VR applications., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2022
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18. Carotid Stent Explant Indications and Outcomes.
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Small C, Thompson T, Scali S, Berceli S, Cooper M, Back M, Upchurch G Jr, Huber T, and Shah S
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- Aged, Carotid Stenosis diagnostic imaging, Comorbidity, Databases, Factual, Endovascular Procedures adverse effects, Female, Humans, Male, Medical Records, Middle Aged, Prosthesis-Related Infections diagnosis, Prosthesis-Related Infections etiology, Recurrence, Retrospective Studies, Risk Assessment, Risk Factors, Time Factors, Treatment Outcome, Carotid Stenosis therapy, Device Removal adverse effects, Endovascular Procedures instrumentation, Prosthesis-Related Infections therapy, Stents adverse effects
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Background: Carotid artery stenting is an alternative to carotid endarterectomy, especially in patients deemed to have significant anatomic or medical risk for the latter. There is scant literature, however, on indications for and outcomes of carotid stent (CAS) explant. We sought to determine indications and outcomes of CAS explant at our institution., Methods: We queried a prospectively maintained institutional vascular surgery database as well as hospital records to identify patients undergoing carotid stent explant from 2010-2020. Ten patients were identified. Their charts were reviewed to obtain demographic, comorbidity, procedural, and outcomes data. Data of particular interest were preoperative atherosclerotic factors, indications for CAS explant, carotid repair strategy, and 30-day post-procedural complications. Data were analyzed for ranges and means., Results: Ten patients were identified. Comorbidity was common: all patients had at least 1 atherosclerotic risk factor, with hypertension and hypercholesterolemia being the most common. Seven (70.0%) patients had recurrent stenosis as the indication for explant. Seven (70.0%) presented symptomatically. Five (50.0%) cases of restenosis had been refractory to angioplasty. There were 3 (30.0%) instances of CAS explant due to infection. Only 1 (12.5%) index CAS was performed at our institution. There was a mean hospital length of stay of 4.5 days. One patient had vocal cord paralysis requiring no intervention. There was no (0%) 30-day mortality, stroke, or postoperative wound infections., Conclusions: Our series had 0% 30-day mortality, stroke, and postoperative wound infection suggesting that CAS explant may be performed safely. Our series is small but represents the largest single institution series to date. This procedure may become increasingly common in the coming years with the more frequent use of CAS; additional data is needed to rigorously understand outcomes., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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19. Printed monolith adsorption as an alternative to expanded bed adsorption for purifying M13 bacteriophage.
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Feast S, Fee C, Huber T, and Clarke D
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- Adsorption, Culture Media, Bacteriophage M13 isolation & purification, Virology instrumentation, Virology methods
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An ordered 3D printed chromatography stationary phase was used to purify M13 bacteriophage (M13) directly from crude cell culture. This new approach, which offers the same advantages as expanded bed adsorption (EBA) with regard to tolerating solids-laden feed streams but without the corresponding issues associated with fluidized bed stability that affect the latter, can be described as "printed monolith adsorption (PMA)". PMA columns (5, 10 and 15 cm length by 1 cm diameter) were made via a wax templating method from cross-linked cellulose hydrogel and functionalized with a quaternary amine ligand. The recovery of M13 was found to be strongly linked to load flow rate, with the highest recovery 89.7% ± 6% for 1.4 × 10
11 pfu/mL of resin occurring at 76 cm/h with a 10 cm column length. A recovery of 87.7% ± 5% for 1.49 × 1011 pfu/mL of media was achieved with a 15 cm column length under conditions comparable to a reported EBA process. The PMA process was completed three times faster than EBA because PMA flow rates can readily be adjusted during operation, with high flow rates and low back pressure, which is unique to the ordered monolithic media geometry used. Equilibration, wash, and cleaning steps were carried out at high flow rates (611 cm/h), minimizing process time and were limited only by the volumetric flow rate capacity of the pumps used, rather than column back pressure (<0.1 MPa at 611 cm/hr). Initial capture of M13 appears to occur on the surface of the monolith solid phase (i.e. the mobile phase channel walls) and subsequently, at a slower rate, within the internal pores of the solid phase media. The difference in binding rate between these two sites is likely caused by slow pore diffusion of the large M13 particles into the pores, with similar slow diffusion out of the pores resulting in tailing of the elution peak. The results indicate that PMA is a promising technology for the efficient purification of viruses directly from crude cell culture., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)- Published
- 2021
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20. The comprehensive complication index is associated with a significant increase in complication severity between 30 and 90 days after radical cystectomy for bladder cancer.
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Haas M, Huber T, Pickl C, van Rhijn BWG, Gužvić M, Gierth M, Breyer J, Burger M, and Mayr R
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- Aged, Female, Humans, Male, Retrospective Studies, Risk Factors, Time Factors, Cystectomy, Postoperative Complications classification, Urinary Bladder Neoplasms surgery
- Abstract
Objective: To assess the true cumulative morbidity after RC by implementing the Comprehensive Complication Index (CCI) over a 90-day period, since recent evidence suggests underreporting of the cumulative morbidity after radical cystectomy (RC) with inconsistent complication rates when reported with conventional reporting systems., Patients and Methods: Medical records of 433 patients with bladder cancer who underwent RC were retrospectively reviewed over a 90-day period. Clinical variables were assessed and complications were graded by the Clavien-Dindo Classification (CDC). The resulting 30- and 90-day CCI-scores were calculated and compared for each patient. Multivariable regression models for developing at least one severe (≥CDC IIIb) complication were designed., Results: Overall, 848 complications were recorded in 371 patients (85.7%). Severe complications occurred in 130 patients (30%) and the cumulative morbidity corresponded to the level of a severe complication in 159 patients (36.7%), meaning an upgrade in 6.7% of patients compared to the CDC. The 90-day CCI (24.2 (median, IQR 20.9-39.7)) was higher than the 30-day CCI (22.6 (median, IQR 8.7-39.7)), (p < 0.001). Comorbidity indices (ASA, ACE 27), BMI, and incontinent urinary diversions were independent risk factors for suffering a severe complication within 90 days post-surgery., Conclusion: The cumulative morbidity (CCI) after RC seems to be higher than previously reported with CDC, especially over a 90-day period. The CCI is an appropriate assessment-tool with an upgrade in morbidity in a significant proportion of patients when compared to the CDC. BMI, several comorbidity indices, and incontinent urinary diversions are independent risk factors for suffering a severe complication after RC., Competing Interests: Declaration of competing interest None., (Copyright © 2020 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)
- Published
- 2021
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21. Innovating and invigorating the clinical trial infrastructure for glomerular diseases.
- Author
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Barisoni L, Barratt J, Campbell K, Eva L, Gillespie BS, Gipson D, Huber T, Jardine M, Kamil E, Kretzler M, Lee L, Levtchenk E, Mehr AP, Nachman PH, Oh J, Saleem M, Shankland SJ, Smith K, Smokler I, Smoyer W, Tarnoff J, Thompson A, Trachtman H, Udani S, Vivarelli M, Walker P, West M, and Rovin BH
- Subjects
- Humans, Glomerulonephritis diagnosis, Glomerulonephritis therapy, Kidney Diseases
- Published
- 2021
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- View/download PDF
22. Editor's Choice - Management of the Diseases of Mesenteric Arteries and Veins: Clinical Practice Guidelines of the European Society of Vascular Surgery (ESVS).
- Author
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Björck M, Koelemay M, Acosta S, Bastos Goncalves F, Kölbel T, Kolkman JJ, Lees T, Lefevre JH, Menyhei G, Oderich G, Esvs Guidelines Committee, Kolh P, de Borst GJ, Chakfe N, Debus S, Hinchliffe R, Kakkos S, Koncar I, Sanddal Lindholt J, Vega de Ceniga M, Vermassen F, Verzini F, Document Reviewers, Geelkerken B, Gloviczki P, Huber T, and Naylor R
- Subjects
- Endovascular Procedures adverse effects, Humans, Mesenteric Arteries diagnostic imaging, Mesenteric Arteries physiopathology, Mesenteric Veins diagnostic imaging, Mesenteric Veins physiopathology, Predictive Value of Tests, Risk Factors, Splanchnic Circulation, Treatment Outcome, Vascular Diseases diagnostic imaging, Vascular Diseases physiopathology, Vascular Surgical Procedures adverse effects, Endovascular Procedures standards, Mesenteric Arteries surgery, Mesenteric Veins surgery, Vascular Diseases therapy, Vascular Surgical Procedures standards
- Published
- 2017
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23. Fractional Anisotropy Correlates with Overall Survival in Glioblastoma.
- Author
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Huber T, Bette S, Wiestler B, Gempt J, Gerhardt J, Delbridge C, Barz M, Meyer B, Zimmer C, and Kirschke JS
- Subjects
- Aged, Brain Neoplasms mortality, Brain Neoplasms pathology, Brain Neoplasms therapy, Chemotherapy, Adjuvant, Diffusion Tensor Imaging, Female, Glioblastoma mortality, Glioblastoma pathology, Glioblastoma therapy, Humans, Image Processing, Computer-Assisted, Magnetic Resonance Imaging, Male, Middle Aged, Multivariate Analysis, Neurosurgical Procedures, Prognosis, Radiotherapy, Adjuvant, Retrospective Studies, Survival Rate, Tumor Burden, Anisotropy, Brain Neoplasms diagnostic imaging, Glioblastoma diagnostic imaging
- Abstract
Objective: Glioblastoma (GB) is an infiltrative disease that results in microstructural damage on a cellular level. Fractional anisotropy (FA) is an important estimate of diffusion tensor imaging (DTI) that can be used to assess microstructural integrity. The aim of this study was to examine the correlation between FA values and overall survival (OS) in patients with GB., Methods: This retrospective single-center study included 122 consecutive patients with GB (50 women; median age, 63 years) with preoperative MRI including fluid attenuated inversion recovery (FLAIR), contrast-enhanced T1-weighted sequences, and DTI. FA and apparent diffusion coefficient (ADC) values in contrast-enhancing lesions (FA-CEL, FA-ADC), nonenhancing lesions, and central tumor regions were correlated to histopathologic and clinical parameters. Univariate and multivariate survival analyses were performed., Results: Patients with low FA-CEL (median <0.31) showed significantly improved OS in univariate analysis (P = 0.028). FA-CEL also showed a positive correlation with Ki-67 proliferation index (P = 0.003). However, in a multivariate survival model, FA values could not be identified as independent prognostic parameters beside established factors such as age and Karnofsky performance scale score. FA values in nonenhancing lesions and central tumor regions and mean ADC values had no distinct influence on OS., Conclusions: FA values can provide prognostic information regarding OS in patients with GB. There is a correlation between FA-CEL values and Ki-67 proliferation index, a marker for malignancy. Noninvasive identification of more aggressive GB growth patterns might be beneficial for preoperative risk evaluation and estimation of prognosis., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2016
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- View/download PDF
24. Value of Early Postoperative FLAIR Volume Dynamic in Glioma with No or Minimal Enhancement.
- Author
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Bette S, Kaesmacher J, Huber T, Delbridge C, Ringel F, Boeckh-Behrens T, Meyer B, Zimmer C, Kirschke JS, and Gempt J
- Subjects
- Adult, Brain Infarction mortality, Brain Infarction pathology, Brain Ischemia mortality, Brain Ischemia pathology, Brain Neoplasms genetics, Brain Neoplasms mortality, Disease-Free Survival, Female, Glioma genetics, Glioma mortality, Humans, Isocitrate Dehydrogenase genetics, Karnofsky Performance Status, Male, Mutation, Postoperative Care methods, Retrospective Studies, Tumor Burden, Brain Neoplasms pathology, Glioma pathology
- Abstract
Objective: The evaluation of postoperative magnetic resonance imaging (MRI) in glioma with no or minimal enhancement is controversial because the evaluation of residual tumor volume can be biased. The purpose of this study was to clarify the value of early postoperative and 3-month MRI regarding its validity in predicting recurrent disease., Methods: For this retrospective, single-center study, overall fluid attenuated inversion recovery (FLAIR) volumes (early postoperative [<48 hours] and 3-month MRI including FLAIR and T1-weighted sequences with and without contrast agent) of 99 patients were assessed using manual segmentation. FLAIR volume dynamic over the first 3 months after surgery and its effect on disease recurrence were evaluated while considering histopathologic features., Results: Overall FLAIR-hyperintense volume significantly decreased between early postoperative and 3-month follow-up MRIs (P < 0.001). Early FLAIR volume increase had a high positive predictive value for overall disease recurrence after resection (85.71% [95%-CI: 62.64-96.24]). Early FLAIR volume dynamic (P < 0.001), isocitrate dehydrogenase 1/2 status (P = 0.002), and preoperative Karnofsky Performance Status (P = 0.012) were observed as independent factors for progression-free survival in multivariate analysis., Conclusion: Early postoperative FLAIR volume assessment in gliomas with no or minimal enhancement is susceptible to a systematic overestimation of residual tumors. Nevertheless, early FLAIR volume dynamic is an independent factor for tumor recurrence that should be evaluated in order timely adapt surveillance and therapy regimens accordingly., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2016
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25. Patterns and Time Dependence of Unspecific Enhancement in Postoperative Magnetic Resonance Imaging After Glioblastoma Resection.
- Author
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Bette S, Gempt J, Huber T, Boeckh-Behrens T, Ringel F, Meyer B, Zimmer C, and Kirschke JS
- Subjects
- Brain diagnostic imaging, Brain surgery, Contrast Media, Follow-Up Studies, Gadolinium DTPA, Humans, Neoplasm Recurrence, Local diagnostic imaging, Neurosurgical Procedures, Retrospective Studies, Time Factors, Brain Neoplasms diagnostic imaging, Brain Neoplasms surgery, Glioblastoma diagnostic imaging, Glioblastoma surgery, Magnetic Resonance Imaging methods, Postoperative Care methods
- Abstract
Objective: Postoperative magnetic resonance imaging (MRI) is recommended soon after glioma surgery to avoid reactive nonneoplastic contrast enhancement indistinguishable from tumor. The purpose of this study was to analyze these patterns of postoperative contrast enhancement at 3 T to define the optimal time frame for postoperative MRI., Methods: MRI for 206 glioblastoma surgeries in 173 patients who underwent pre- and postoperative and at least 1 follow-up 3T MRI for each surgery were analyzed retrospectively. Postoperative MRI was assessed in consensus by 2 neuroradiologists, blinded to the time after surgery. Postoperative contrast enhancement marginal to the resection cavity was analyzed and classified as vascular, linear, or nodular. The cause of the contrast enhancement (ie, reactive vs. tumor) was assessed by comparing pre-, postoperative, and follow-up MRI., Results: Within 45 hours after surgery, reactive enhancement appeared in 17.9% of cases. After 45 hours, the fraction of reactive changes increased to 34.1%. Linear enhancement was more often reactive (66.1%, 39/59 cases), whereas nodular enhancement was mainly residual tumor (93.2%, 68/73 cases). Specificity of nodular enhancement was high for tumor recurrence/tumor progression (91.5%)., Conclusions: To avoid an increasing number of MRIs with reactive contrast enhancement, postoperative MRI at 3 T should be performed within 45 hours after surgery. However, reactive contrast enhancement can occur at all time points. In these cases, the pattern of the contrast enhancement may help to differentiate its cause., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2016
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26. Prognostic Value of O-(2-[18F]-Fluoroethyl)-L-Tyrosine-Positron Emission Tomography Imaging for Histopathologic Characteristics and Progression-Free Survival in Patients with Low-Grade Glioma.
- Author
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Bette S, Gempt J, Delbridge C, Kirschke JS, Schlegel J, Foerster S, Huber T, Pyka T, Zimmer C, Meyer B, and Ringel F
- Subjects
- Adult, Biomarkers, Tumor genetics, Biomarkers, Tumor metabolism, Brain metabolism, Brain pathology, Brain surgery, Brain Neoplasms genetics, Brain Neoplasms metabolism, Brain Neoplasms pathology, Disease-Free Survival, Female, Glioma pathology, Humans, Kaplan-Meier Estimate, Magnetic Resonance Imaging, Male, Neoplasm Grading, Neoplasm Recurrence, Local diagnostic imaging, Neoplasm Recurrence, Local genetics, Neoplasm Recurrence, Local metabolism, Neoplasm Recurrence, Local pathology, Prognosis, Radiopharmaceuticals, Retrospective Studies, Sensitivity and Specificity, Tumor Burden, Tyrosine analogs & derivatives, Brain diagnostic imaging, Brain Neoplasms diagnostic imaging, Glioma diagnostic imaging, Positron-Emission Tomography
- Abstract
Objective: O-(2-[18F]-fluoroethyl)-L-tyrosine positron emission tomography ((18)F-FET-PET) imaging is applied for tumor grading, prognostic stratification, and diagnosis of tumor recurrence, especially in high-grade gliomas. Experience with (18)F-FET-PET imaging in low-grade gliomas is limited. Therefore, the objective of the present study was to assess (18)F-FET-PET tracer uptake in low-grade gliomas and to investigate possible correlations with contrast enhancement in magnetic resonance imaging (MRI) and histopathology., Methods: A total of 65 patients (29 female, 36 male, median age 38 years) with newly diagnosed or recurrent low-grade gliomas for whom preoperative MRI and (18)F-FET-PET imaging were available were included. Tumor entity, tumor location, as well as histopathology (isocitrate dehydrogenase [IDH] 1/2 mutation, Ki67, p53, oligodendroglial differentiation, 1p19q codeletion), and progression-free survival were assessed. (18)F-FET-PET images were acquired and fused to MRI (T2-weighted fluid-attenuated inversion recovery) and tumor volume was measured in areas with a tumor-to-background ratio >1.3, >1.6, and >2.0 and in MRI., Results: PET tracer uptake was observed in 78.5% of all World Health Organization Grade I and II tumors. (18)F-FET uptake showed a high negative predictive value for oligodendroglial components and for 1p19q codeletion. No further significant correlation between histologic features, progression-free survival, or IDH1/2 mutation status and tracer uptake was observed., Conclusions: We found that 78.5% of low-grade gliomas do show elevated tracer uptake in (18)F-FET-PET imaging. Low-grade glioma without tracer uptake exclude oligodendroglial differentiation and 1p19q codeletion. Further differentiation between molecular subtypes is not possible with static (18)F-FET-PET. No correlation of progression-free survival to tracer uptake and IDH1/2-mutation status was observed., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2016
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27. Pseudocontact Shift-Driven Iterative Resampling for 3D Structure Determinations of Large Proteins.
- Author
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Pilla KB, Otting G, and Huber T
- Subjects
- Models, Molecular, Magnetic Resonance Spectroscopy methods, Protein Conformation, Proteins chemistry
- Abstract
Pseudocontact shifts (PCSs) induced by paramagnetic lanthanides produce pronounced effects in nuclear magnetic resonance spectra, which are easily measured and which deliver valuable long-range structure restraints. Even sparse PCS data greatly enhance the success rate of 3D (3-dimensional) structure predictions of proteins by the modeling program Rosetta. The present work extends this approach to 3D structures of larger proteins, comprising more than 200 residues, which are difficult to model by Rosetta without additional experimental restraints. The new algorithm improves the fragment assembly method of Rosetta by utilizing PCSs generated from paramagnetic lanthanide ions attached at four different sites as the only experimental restraints. The sparse PCS data are utilized at multiple stages, to identify native-like local structures, to rank the best structural models and to rebuild the fragment libraries. The fragment libraries are refined iteratively until convergence. The PCS-driven iterative resampling algorithm is strictly data dependent and shown to generate accurate models for a benchmark set of eight different proteins, ranging from 100 to 220 residues, using solely PCSs of backbone amide protons., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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28. Bioorthogonal Labeling of Ghrelin Receptor to Facilitate Studies of Ligand-Dependent Conformational Dynamics.
- Author
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Park M, Sivertsen BB, Els-Heindl S, Huber T, Holst B, Beck-Sickinger AG, Schwartz TW, and Sakmar TP
- Subjects
- Antibodies, Monoclonal chemistry, Antibodies, Monoclonal immunology, Azides chemistry, Cycloaddition Reaction, Fluorescence Resonance Energy Transfer, Fluorescent Dyes chemistry, Humans, Organometallic Compounds chemistry, Phenylalanine analogs & derivatives, Phenylalanine chemistry, Protein Conformation, Receptors, Ghrelin genetics, Receptors, Ghrelin metabolism, Ligands, Receptors, Ghrelin chemistry
- Abstract
Ghrelin receptor (GhrR) is a promising drug target because of its central role in energy homeostasis. GhrR, known for high constitutive activity, is thought to display multi-state conformations during activation and signaling. We used genetically encoded unnatural amino acids and bioorthogonal labeling reactions to engineer multiple fluorescent donor-acceptor pairs to probe ligand-directed structural changes in GhrR. We demonstrate how conformational dynamics of a G-protein-coupled receptor can be measured in reconstituted systems., (Copyright © 2015 Elsevier Ltd. All rights reserved.)
- Published
- 2015
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29. Chemical biology methods for investigating G protein-coupled receptor signaling.
- Author
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Huber T and Sakmar TP
- Subjects
- Azides chemistry, Cycloaddition Reaction, Fluorescent Dyes chemistry, Maleimides chemistry, Quantum Dots chemistry, Receptors, G-Protein-Coupled chemistry, Rhodamines chemistry, Ultraviolet Rays, Receptors, G-Protein-Coupled metabolism, Signal Transduction
- Abstract
G protein-coupled receptors (GPCRs) are targets for a quarter of prescription drugs. Despite recent progress in structural biology of GPCRs, only few key conformational states in the signal transduction process have been elucidated. Agonist ligands frequently display functional selectivity where activated receptors are biased to either G protein- or arrestin-mediated downstream signaling pathways. Selective manipulation of individual steps in the GPCR activation scheme requires precise information about the kinetics of ligand binding and the dynamics of downstream signaling. One approach is to obtain time-resolved information using receptors tagged with fluorescent or structural probes. Recent advances allow for site-specific introduction of genetically encoded unnatural amino acids into expressed GPCRs. We describe how bioorthogonal functional groups on GPCRs enable the mapping of receptor-ligand interactions and how bioorthogonal chemical reactions can be used to introduce fluorescent labels for single-molecule fluorescence applications to study the kinetics and conformational dynamics of GPCR signaling complexes ("signalosomes")., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2014
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30. W-band orientation selective DEER measurements on a Gd3+/nitroxide mixed-labeled protein dimer with a dual mode cavity.
- Author
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Kaminker I, Tkach I, Manukovsky N, Huber T, Yagi H, Otting G, Bennati M, and Goldfarb D
- Subjects
- Dimerization, Proteins analysis, Algorithms, Electron Spin Resonance Spectroscopy methods, Gadolinium chemistry, Nitrogen Oxides chemistry, Proteins chemistry
- Abstract
Double electron-electron resonance (DEER) at W-band (95 GHz) was applied to measure the distance between a pair of nitroxide and Gd(3+) chelate spin labels, about 6 nm apart, in a homodimer of the protein ERp29. While high-field DEER measurements on systems with such mixed labels can be highly attractive in terms of sensitivity and the potential to access long distances, a major difficulty arises from the large frequency spacing (about 700 MHz) between the narrow, intense signal of the Gd(3+) central transition and the nitroxide signal. This is particularly problematic when using standard single-mode cavities. Here we show that a novel dual-mode cavity that matches this large frequency separation dramatically increases the sensitivity of DEER measurements, allowing evolution times as long as 12 μs in a protein. This opens the possibility of accessing distances of 8 nm and longer. In addition, orientation selection can be resolved and analyzed, thus providing additional structural information. In the case of W-band DEER on a Gd(3+)-nitroxide pair, only two angles and their distributions have to be determined, which is a much simpler problem to solve than the five angles and their distributions associated with two nitroxide spin labels., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2013
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31. Protein structure determination from pseudocontact shifts using ROSETTA.
- Author
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Schmitz C, Vernon R, Otting G, Baker D, and Huber T
- Subjects
- Anisotropy, Magnetics methods, Metals chemistry, Models, Molecular, Protein Conformation, Protein Folding, Nuclear Magnetic Resonance, Biomolecular methods, Proteins chemistry
- Abstract
Paramagnetic metal ions generate pseudocontact shifts (PCSs) in nuclear magnetic resonance spectra that are manifested as easily measurable changes in chemical shifts. Metals can be incorporated into proteins through metal binding tags, and PCS data constitute powerful long-range restraints on the positions of nuclear spins relative to the coordinate system of the magnetic susceptibility anisotropy tensor (Δχ-tensor) of the metal ion. We show that three-dimensional structures of proteins can reliably be determined using PCS data from a single metal binding site combined with backbone chemical shifts. The program PCS-ROSETTA automatically determines the Δχ-tensor and metal position from the PCS data during the structure calculations, without any prior knowledge of the protein structure. The program can determine structures accurately for proteins of up to 150 residues, offering a powerful new approach to protein structure determination that relies exclusively on readily measurable backbone chemical shifts and easily discriminates between correctly and incorrectly folded conformations., (Copyright © 2011. Published by Elsevier Ltd.)
- Published
- 2012
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32. Functional role of the "ionic lock"--an interhelical hydrogen-bond network in family A heptahelical receptors.
- Author
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Vogel R, Mahalingam M, Lüdeke S, Huber T, Siebert F, and Sakmar TP
- Subjects
- Amino Acid Sequence, Animals, Binding Sites, Cattle, Hydrogen-Ion Concentration, Models, Molecular, Molecular Sequence Data, Point Mutation, Rhodopsin genetics, Rhodopsin metabolism, Spectroscopy, Fourier Transform Infrared, Structure-Activity Relationship, Hydrogen Bonding, Protein Structure, Tertiary, Rhodopsin chemistry
- Abstract
Activation of family A G-protein-coupled receptors involves a rearrangement of a conserved interhelical cytoplasmic hydrogen bond network between the E(D)RY motif on transmembrane helix 3 (H3) and residues on H6, which is commonly termed the cytoplasmic "ionic lock." Glu134(3.49) of the E(D)RY motif also forms an intrahelical salt bridge with neighboring Arg135(3.50) in the dark-state crystal structure of rhodopsin. We examined the roles of Glu134(3.49) and Arg135(3.50) on H3 and Glu247(6.30) and Glu249(6.32) on H6 on the activation of rhodopsin using Fourier transform infrared spectroscopy of wild-type and mutant pigments reconstituted into lipid membranes. Activation of rhodopsin is pH-dependent with proton uptake during the transition from the inactive Meta I to the active Meta II state. Glu134(3.49) of the ERY motif is identified as the proton-accepting group, using the Fourier transform infrared protonation signature and the absence of a pH dependence of activation in the E134Q mutant. Neutralization of Arg135(3.50) similarly leads to pH-independent receptor activation, but with structural alterations in the Meta II state. Neutralization of Glu247(6.30) and Glu249(6.32) on H6, which are involved in interhelical interactions with H3 and H7, respectively, led to a shift toward Meta II in the E247Q and E249Q mutants while retaining the pH sensitivity of the equilibrium. Disruption of the interhelical interaction of Glu247(6.30) and Glu249(6.32) on H6 with H3 and H7 plays its role during receptor activation, but neutralization of the intrahelical salt bridge between Glu134(3.49) and Arg135(3.50) is considerably more critical for shifting the photoproduct equilibrium to the active conformation. These conclusions are discussed in the context of recent structural data of the beta(2)-adrenergic receptor.
- Published
- 2008
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33. Rapid incorporation of functional rhodopsin into nanoscale apolipoprotein bound bilayer (NABB) particles.
- Author
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Banerjee S, Huber T, and Sakmar TP
- Subjects
- Amino Acid Sequence, Animals, Apolipoprotein A-I chemistry, Apolipoprotein A-I genetics, Apolipoprotein A-I isolation & purification, Biomimetics methods, Cattle, Fluorescent Dyes pharmacology, Humans, Molecular Sequence Data, Phosphatidylcholines chemistry, Phosphatidylcholines metabolism, Receptors, G-Protein-Coupled analysis, Rho Factor physiology, Rhodopsin physiology, Sequence Homology, Amino Acid, Zebrafish genetics, Apolipoprotein A-I metabolism, Lipid Bilayers metabolism, Nanoparticles chemistry, Rhodopsin pharmacokinetics
- Abstract
Human apolipoprotein A-I (apo A-I) and its engineered constructs form discoidal lipid bilayers upon interaction with lipids in vitro. We now report the cloning, expression, and purification of apo A-I derived from zebrafish (Danio rerio), which combines with phospholipids to form similar discoidal bilayers and may prove to be superior to human apo A-I constructs for rapid reconstitution of seven-transmembrane helix receptors into nanoscale apolipoprotein bound bilayers (NABBs). We characterized NABBs by gel-filtration chromatography, native polyacrylamide gradient gel electrophoresis, UV-visible photobleaching difference spectroscopy, and fluorescence spectroscopy. We used electron microscopy to determine the stoichiometry and orientation of rhodopsin (rho)-containing NABBs prepared under various conditions and correlated stability and signaling efficiency of rho in NABBs with either one or two receptors. We discovered that the specific activity of G protein coupling for single rhos sequestered in individual NABBs was nearly identical with that of two rhos per NABB under conditions where stoichiometry and orientation could be inferred by electron microscopy imaging. Thermal stability of rho in NABBs was superior to that of rho in various commonly used detergents. We conclude that the NABB system using engineered zebrafish apo A-I is a native-like membrane mimetic system for G-protein-coupled receptors and discuss strategies for rapid incorporation of expressed membrane proteins into NABBs.
- Published
- 2008
- Full Text
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34. Focusing in on structural genomics: the University of Queensland structural biology pipeline.
- Author
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Puri M, Robin G, Cowieson N, Forwood JK, Listwan P, Hu SH, Guncar G, Huber T, Kellie S, Hume DA, Kobe B, and Martin JL
- Subjects
- Animals, Arthritis drug therapy, Arthritis genetics, Arthritis metabolism, Crystallography, X-Ray methods, Drug Design, Humans, Macrophages metabolism, Models, Molecular, Pulmonary Disease, Chronic Obstructive drug therapy, Pulmonary Disease, Chronic Obstructive genetics, Pulmonary Disease, Chronic Obstructive metabolism, Queensland, Universities, Proteomics methods, Proteomics organization & administration
- Abstract
The flood of new genomic sequence information together with technological innovations in protein structure determination have led to worldwide structural genomics (SG) initiatives. The goals of SG initiatives are to accelerate the process of protein structure determination, to fill in protein fold space and to provide information about the function of uncharacterized proteins. In the long-term, these outcomes are likely to impact on medical biotechnology and drug discovery, leading to a better understanding of disease as well as the development of new therapeutics. Here we describe the high throughput pipeline established at the University of Queensland in Australia. In this focused pipeline, the targets for structure determination are proteins that are expressed in mouse macrophage cells and that are inferred to have a role in innate immunity. The aim is to characterize the molecular structure and the biochemical and cellular function of these targets by using a parallel processing pipeline. The pipeline is designed to work with tens to hundreds of target gene products and comprises target selection, cloning, expression, purification, crystallization and structure determination. The structures from this pipeline will provide insights into the function of previously uncharacterized macrophage proteins and could lead to the validation of new drug targets for chronic obstructive pulmonary disease and arthritis.
- Published
- 2006
- Full Text
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35. Effect of morphological properties of transferred embryonic stages on tubal migration Implications for in vivo culture in the bovine oviduct.
- Author
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Wetscher F, Havlicek V, Huber T, Müller M, Brem G, and Besenfelder U
- Subjects
- Alginates, Animals, Blastocyst physiology, Estrus Synchronization, Female, Glucuronic Acid, Hexuronic Acids, Hyaluronic Acid, Oocytes physiology, Ovarian Follicle cytology, Pregnancy, Tissue and Organ Harvesting veterinary, Zygote physiology, Cattle, Embryo Culture Techniques veterinary, Embryo Transfer veterinary, Embryonic Development, Fallopian Tubes
- Abstract
In cattle, there is no practical method, which allows tubal transfer of pre-implantation embryos for routine in vivo culture as it has been established in sheep. The aim of our study was to perform tubal transfer by transvaginal endoscopy in synchronized heifers, in order to expose embryos at various embryonic stages to the physiological mechanisms of migration in the non-ligated oviducts. Various embryonic stages were transferred by transvaginal endoscopy into the oviducts of temporary recipients and were recovered on Day 7. The transfer of embryos in hyaluronate containing medium ("Hyaluronan"), zygotes stripped of cumulus ("Denuded Zygotes"), embryos embedded in cumulus ("Zygotes with Cumulus"), matured oocytes with capacitated spermatozoa ("GIFT") or embryos embedded in Na alginate ("Alginate") led to increasing recovery rates (13, 30, 56, 63 and 71%, respectively). However, the developmental rate on Day 7 was adversely affected (16, 11, 8, 16 and 8%), whereas the blastocyst rate on Day 8 showed more balanced results (17, 14, 18, 21 and 11%). Our data demonstrate that the structural properties of transferred embryos affect tubal migration and are crucial for subsequent in vivo culture. Embryos enclosed in cumulus cells or alginate synchronize more successfully with the oviductal transport systems than denuded stages or embryos in hyaluronate containing medium.
- Published
- 2005
- Full Text
- View/download PDF
36. Intrafallopian transfer of gametes and early stage embryos for in vivo culture in cattle.
- Author
-
Wetscher F, Havlicek V, Huber T, Gilles M, Tesfaye D, Griese J, Wimmers K, Schellander K, Müller M, Brem G, and Besenfelder U
- Subjects
- Animals, Blastocyst physiology, Cell Culture Techniques, Embryo Culture Techniques veterinary, Embryo Transfer veterinary, Female, Fertilization in Vitro veterinary, Oocytes physiology, Ovarian Follicle cytology, Pregnancy, Time Factors, Tissue and Organ Harvesting veterinary, Cattle, Gamete Intrafallopian Transfer veterinary, Zygote Intrafallopian Transfer veterinary
- Abstract
It may be possible to avoid inadequate in vitro culture conditions by incubating gametes or embryos in the oviducts for a short time. Ideally, an optimized procedure should be devised, combining in vitro and in vivo systems, in order to achieve synchronization in cattle. We transferred gametes as well as embryos in various stages of development and placed them into the oviducts. Embryos were recovered on Day 7 by flushing of oviducts and uterine horns. Blastocyst rates were determined on Day 7 and on Day 8. Experimental designs included transfer of in vitro matured cumulus oocyte complexes into previously inseminated heifers (COCs group), transfer of in vitro matured COCs simultaneously with capacitated spermatozoa (GIFTs group), transfer of four to eight cell stage embryos developed in vitro after IVM/IVF (Cleaved Stages group) and a group of solely in vitro produced embryos (IVP control group). Our results indicate that in vivo culture of IVM/IVF embryos in the homologous bovine oviduct has a positive influence on subsequent pre-implantation development. In addition, we have evidence that in vitro maturation and in vivo fertilization cannot be synchronized.
- Published
- 2005
- Full Text
- View/download PDF
37. How specific are deficits in mismatch negativity generation to schizophrenia?
- Author
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Umbricht D, Koller R, Schmid L, Skrabo A, Grübel C, Huber T, and Stassen H
- Subjects
- Adult, Case-Control Studies, Electrophysiology, Evoked Potentials, Auditory, Female, Functional Laterality, Humans, Intelligence, Male, Memory, Middle Aged, Bipolar Disorder physiopathology, Depressive Disorder, Major physiopathology, Hearing, Schizophrenia physiopathology
- Abstract
Background: Mismatch negativity (MMN) is an auditory event-related potential that provides an index of auditory sensory memory. Deficits in MMN generation have been repeatedly demonstrated in chronic schizophrenia. Their specificity to schizophrenia has not been established., Methods: Mismatch negativity to both duration and frequency deviants was investigated in gender- and age-matched patients with schizophrenia or schizoaffective disorder (n = 26), bipolar disorder (n = 16), or major depression (n = 22) and healthy control subjects (n = 25)., Results: Only patients with schizophrenia demonstrated significantly smaller mean MMN than did healthy control subjects. Detailed analyses showed significantly smaller MMN to both duration and frequency deviants in patients with schizophrenia than in healthy control subjects; however, the reduction of frequency MMN in patients with schizophrenia was not significant in the comparison across all groups. Mismatch negativity topography did not differ among groups. No consistent correlations with clinical, psychopathologic, or treatment variables were observed., Conclusions: Mismatch negativity deficits, and by extension deficits in early cortical auditory information processing, appear to be specific to schizophrenia. Animal and human studies implicate dysfunctional N-methyl-D-aspartate receptor functioning in MMN deficits. Thus MMN deficits may become a useful endophenotype to investigate the genetic underpinnings of schizophrenia, particularly with regard to the N-methyl-D-aspartate receptor.
- Published
- 2003
- Full Text
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38. Biophysical properties of human antibody variable domains.
- Author
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Ewert S, Huber T, Honegger A, and Plückthun A
- Subjects
- Amino Acid Sequence, Complementarity Determining Regions, Guanidine chemistry, Humans, Hydrophobic and Hydrophilic Interactions, Immunoglobulin Heavy Chains genetics, Immunoglobulin Heavy Chains metabolism, Immunoglobulin Light Chains genetics, Immunoglobulin Light Chains metabolism, Immunoglobulin Variable Region metabolism, Models, Molecular, Molecular Sequence Data, Molecular Weight, Peptide Fragments genetics, Peptide Fragments isolation & purification, Peptide Fragments metabolism, Peptide Library, Protein Denaturation, Protein Structure, Tertiary, Sequence Alignment, Solubility, Immunoglobulin Heavy Chains chemistry, Immunoglobulin Light Chains chemistry, Immunoglobulin Variable Region chemistry, Peptide Fragments chemistry
- Abstract
There are great demands on the stability, expression yield and resistance to aggregation of antibody fragments. To untangle intrinsic domain effects from domain interactions, we present first a systematic evaluation of the isolated human immunoglobulin variable heavy (V(H)) and light (V(L)) germline family consensus domains and then a systematic series of V(H)-V(L) combinations in the scFv format. The constructs were evaluated in terms of their expression behavior, oligomeric state in solution and denaturant-induced unfolding equilibria under non-reducing conditions. The seven V(H) and seven V(L) domains represent the consensus sequences of the major human germline subclasses, derived from the Human Combinatorial Antibody Library (HuCAL). The isolated V(H) and V(L) domains with the highest thermodynamic stability and yield of soluble protein were V(H)3 and V(kappa)3, respectively. Similar measurements on all domain combinations in scFv fragments allowed the scFv fragments to be classified according to thermodynamic stability and in vivo folding yield. The scFv fragments containing the variable domain combinations H3kappa3, H1bkappa3, H5kappa3 and H3kappa1 show superior properties concerning yield and stability. Domain interactions diminish the intrinsic differences of the domains. ScFv fragments containing V(lambda) domains show high levels of stability, even though V(lambda) domains are surprisingly unstable by themselves. This is due to a strong interaction with the V(H) domain and depends on the amino acid sequence of the CDR-L3. On the basis of these analyses and model structures, we suggest possibilities for further improvement of the biophysical properties of individual frameworks and give recommendations for library design., (Copyright 2003 Elsevier Science Ltd.)
- Published
- 2003
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39. Angiotensin II increases the cytosolic calcium activity in rat podocytes in culture.
- Author
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Henger A, Huber T, Fischer KG, Nitschke R, Mundel P, Schollmeyer P, Greger R, and Pavenstädt H
- Subjects
- Animals, Cells, Cultured, Extracellular Space metabolism, Flufenamic Acid pharmacology, Kidney Glomerulus cytology, Nicardipine pharmacology, Osmolar Concentration, Rats, Receptors, Angiotensin physiology, Angiotensin II pharmacology, Calcium metabolism, Cytosol metabolism, Kidney Glomerulus drug effects, Kidney Glomerulus metabolism
- Abstract
In the glomerulus, angiotensin II (Ang II) reduces the ultrafiltration coefficient and enhances the filtration of macromolecules. During glomerular injury, inhibition of the renin-angiotensin system by angiotensin-converting-enzyme inhibitors reduces proteinuria and retards the progression to end-stage renal insufficiency. The mechanisms by which Ang II modulates glomerular function are still a matter of investigation. To study whether Ang II may regulate the cytosolic calcium activity ([Ca2+]i) in podocytes, these cells were propagated in short-term culture and the effect of Ang II was examined with the Fura-2 microfluorescence technique in single podocytes. The cellular identity of cultured podocytes was proven by the expression of WT-1 and pp44, specific antibodies against podocytes in vivo. Ang II led to a concentration-dependent, reversible and slow increase of [Ca2+]i with an EC50 of 3 nmol/liter Ang II (N = 229). Ten nmol/liter Ang II increased [Ca2+]i from 41 +/- 9 to 260 +/- 34 nmol/liter (N = 210). In a solution with an extracellular reduced Ca2+ concentration of 10 micromol/liter, Ang II-mediated [Ca2+]i increase was significantly reduced by 60 +/- 20% (N = 12), indicating that the [Ca2+]i increase was due to a Ca2+ influx from the extracellular space and a release of Ca2+ from intracellular stores. Flufenamate, an inhibitor of non-selective ion channels, significantly inhibited Ang II-mediated increase of [Ca2+]i (IC50 = 20 micromol/liter, N = 29), whereas the L-type Ca2+ channel blocker nicardipine even in high concentrations of > 1 micromol/liter had only a small inhibitory effect. The AT1 receptor antagonist losartan inhibited Ang II-mediated [Ca2+]i increase with an IC50 of about 0.3 nmol/liter (N = 35). The data suggest that Ang II increases [Ca2+]i in podocytes by an influx of Ca2+ through non-selective channels and by a release of Ca2+ from intracellular stores. The effect of Ang II is mediated via an AT1 receptor.
- Published
- 1997
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