1
|
Bruysters MWP, Schiffelers MJ, Hoonakker M, Jungbaeck C, Ragan I, Rommel E, van der Stappen T, Viviani L, Hessel EV, Akkermans AM, Vandebriel RJ. Drivers and barriers in the consistency approach for vaccine batch release testing: Report of an international workshop. Biologicals 2017; 48:1-5. [PMID: 28666717 DOI: 10.1016/j.biologicals.2017.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 06/13/2017] [Accepted: 06/19/2017] [Indexed: 11/25/2022] Open
Abstract
Safety and potency assessment for batch release testing of established vaccines still relies partly on animal tests. An important avenue to move to batch release without animal testing is the consistency approach. This approach is based on thorough characterization of the vaccine, and the principle that the quality of subsequent batches is the consequence of the application of consistent production of batches monitored by a GMP quality system. Efforts to implement the consistency approach are supported by several drivers from industry, government, and research, but there are also several barriers that must be overcome. A workshop entitled "Consistency Approach, Drivers and Barriers" was organized, which aimed to discuss and identify drivers and barriers for the implementation of the 3Rs in the consistency approach from three different perspectives/domains (industry, regulatory and science frameworks). The workshop contributed to a better understanding of these drivers and barriers and resulted in recommendations to improve the overall regulatory processes for the consistency approach. With this report, we summarise the outcome of this workshop and intend to offer a constructive contribution to the international discussion on regulatory acceptance of the consistency approach.
Collapse
Affiliation(s)
- Martijn W P Bruysters
- National Institute of Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven, The Netherlands.
| | - Marie-Jeanne Schiffelers
- Utrecht University School of Governance (USBO), Bijlhouwerstraat 6, 3511 ZC Utrecht, The Netherlands.
| | - Marieke Hoonakker
- Institute for Translational Vaccinology (Intravacc), Bilthoven, The Netherlands.
| | - Carmen Jungbaeck
- Paul-Ehrlich-Institut, Paul-Ehrlich-Straße 51-59, D-63225 Langen, Germany.
| | - Ian Ragan
- NC3Rs Board, Gibbs Building, 215 Euston Road, London NW1 2BE, UK.
| | - Eddy Rommel
- Rommel Consulting Partners, B-1370 Jodoigne, Belgium.
| | | | | | - Ellen V Hessel
- National Institute of Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven, The Netherlands.
| | - Arnoud M Akkermans
- National Institute of Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven, The Netherlands.
| | - Rob J Vandebriel
- National Institute of Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven, The Netherlands.
| |
Collapse
|
2
|
Morgalla M, Rommel E, Bitzer M, Mettenleiter H, Grote E. The HanniSet External Ventricular Pressure Transducer and Drainage System: Experimental and Clinical Evaluation. J Intensive Care Med 2016. [DOI: 10.1177/088506669901400504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
3
|
De Mattia F, Hendriksen C, Buchheit KH, Chapsal JM, Halder M, Lambrigts D, Redhead K, Rommel E, Scharton-Kersten T, Sesardic T, Viviani L, Ragan I. The vaccines consistency approach project: an EPAA initiative. Pharmeur Bio Sci Notes 2015; 2015:30-56. [PMID: 26830158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The consistency approach for release testing of established vaccines promotes the use of in vitro, analytical, non-animal based systems allowing the monitoring of quality parameters during the whole production process. By using highly sensitive non-animal methods, the consistency approach has the potential to improve the quality of testing and to foster the 3Rs (replacement, refinement and reduction of animal use) for quality control of established vaccines. This concept offers an alternative to the current quality control strategy which often requires large numbers of laboratory animals. In order to facilitate the introduction of the consistency approach for established human and veterinary vaccine quality control, the European Partnership for Alternatives to Animal Testing (EPAA) initiated a project, the "Vaccines Consistency Approach Project", aiming at developing and validating the consistency approach with stakeholders from academia, regulators, OMCLs, EDQM, European Commission and industry. This report summarises progress since the project's inception.
Collapse
Affiliation(s)
- F De Mattia
- MSD Animal Health, PO Box 31, 5830 AA Boxmeer, Netherlands
| | - C Hendriksen
- Utrecht University, Department of Animals in Science and Society, Faculty of Veterinary Medicine, PO Box 80.166, 3508TD Utrecht, Netherlands
| | - K H Buchheit
- European Directorate for the Quality of Medicines & HealthCare (EDQM), Department of Biological Standardisation, OMCL Network & HealthCare (DBO), Council of Europe, Strasbourg, France
| | | | - M Halder
- European Commission, Joint Research Centre, Institute for Health and Consumer Protection, Systems Toxicology Unit/EURL ECVAM, 21027 Ispra, Italy
| | | | - K Redhead
- Vaccine & Assay Consultancy, Watford, WD25 0EX, UK
| | - E Rommel
- Rommel Consulting Partners, B-1370 Jodoigne, Belgium
| | - T Scharton-Kersten
- Novartis Vaccines and Diagnostics AG, Basel, Switzerland (currently: International AIDS Vaccine Initiative New York, New York, USA)
| | - T Sesardic
- Division of Bacteriology, National Institute for Biological Standards and Control (NIBSC). Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, United Kingdom
| | - L Viviani
- Novartis Vaccines and Diagnostics AG, Basel, Switzerland
| | | |
Collapse
|
4
|
Abstract
Abstract
In single crystals the NQR nutation frequency depends on the relative orientation of the coil and the quadrupole axes. In powders the nutation lineshape is a superposition of spectra from the randomly oriented single crystals, so that powder patterns appear in such experiments if the reconstruction is performed by the Fourier transform method. In this paper an alternative reconstruction method of nutation spectra is suggested making use of the Hankel Transform. In this way the nutation spectra are simplified. Singularities arising with experiments for the determination of the asymmetry parameter η can easily be resolved. In the particular case of an axially symmetric quadrupolar tensor and a homogeneous radiofrequency field one can reduce the powder pattern to a single line without heterogeneous broadening with respect to orientation. Further improvement o f the nutation spectra can be achieved by taking advantage of the maximum entropy method, which strongly reduces apodisation and noise problems. Applications of the new data manipulation techniques to N Q R imaging methods published elsewhere and 2D zero-field N Q R spectroscopy are reported.
Collapse
Affiliation(s)
- H. Robert
- Facultad de Matemätica, Astronom ia y Fisica, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba, Argentina
| | - D. Pusiol
- Facultad de Matemätica, Astronom ia y Fisica, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba, Argentina
| | - E. Rommel
- Sektion Kernresonanzspektroskopie, Universität Ulm, 89069 Ulm, Germany
| | - R. Kimmich
- Sektion Kernresonanzspektroskopie, Universität Ulm, 89069 Ulm, Germany
| |
Collapse
|
5
|
Davidson SM, Duchen MM, Yellon DM, Fields L, Zaccolo M, Laeremans H, Daskalopoulos EP, Janssen BJA, Blankesteijn WM, Tillmanns J, Hoffmann D, Habbaba Y, Fraccarollo D, Galuppo P, Bauersachs J, Novella S, Segarra G, Dantas AP, Bueno-Beti C, Novensa L, Lazaro-Franco M, Martinez-Gil N, Medina P, Hermenegildo C, Ohanian J, Liao A, Trafford AW, Ohanian V, Perez-Moreno A, Garcia-Canadilla P, Dominguez JM, Crispi F, Gratacos E, Amat-Roldan I, Gotschy A, Herold V, Bauer E, Schrodt C, Lykowsky G, Rommel E, Jakob P, Bauer W, Shah M, Sikkel MB, Desplantez T, Collins TP, O'Gara P, Harding SE, Lyon AR, Macleod KT, Ferrantini C, Sacconi L, Lotti I, Coppini R, Tesi C, Yan P, Loew LM, Cerbai E, Poggesi C, Pavone FS, Franco D, Daimi H, Dominguez JN, Hove-Madsen L, Cinca J, Vazquez E, Aranega AE, Poon KL, Kirchmaier BC, Schwerte T, Huisken J, Winkler C, Jungblut BC, Stainier DY, Brand T, Stuckey DJ, Tremoleda JL, Mcsweeney S, Fiedler L, Harada M, Carr CA, Tyler DJ, Gsell W, Clarke K, Schneider MD, Sequeira V, Regan JA, Michels M, Ten Cate FJ, Van Slegtenhorst MA, Stienen GJM, Dos Remedios C, Van Der Velden J. Oral abstract presentations. Cardiovasc Res 2012. [DOI: 10.1093/cvr/cvr335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
6
|
Frydrychowicz A, Spindler M, Rommel E, Ertl G, Haase A, Neubauer S, Wiesmann F. Functional Assessment of Isolated Right Heart Failure by High Resolution In-Vivo Cardiovascular Magnetic Resonance in Mice. J Cardiovasc Magn Reson 2007; 9:623-7. [PMID: 17365246 DOI: 10.1080/10976640600945507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Precise and noninvasive characterization of the development of the cardiac phenotype in murine models of heart failure has been widely demanded in modern cardiovascular research. High-resolution cardiovascular magnetic resonance (CMR) has been proven to be a powerful tool for the accurate and reproducible assessment of LV and RV parameters in healthy mice. Whereas changes in LV parameters in models of heart failure have been thoroughly evaluated, RV dysfunction has not. Purpose of this study was to characterize a model of isolated RV failure induced by pulmonal banding by in vivo CMR at 7T. RV parameters differed significantly from those of normal mice in terms of RV end-diastolic volume (EDV: 85 +/- 14 microL vs. control 36 +/- 3 microL, p < 0.0001), RV end-systolic volume (ESV: 121 +/- 10 microL vs. control 84 +/- 4 microL, p < 0.005) and RV ejection fraction (EF: 31 +/- 6 % vs. control 57 +/- 2 %, p < 0.001). With regard to EDV, ESV, SV and EF LV parameters, there were no significant differences between pulmonary banded and control mice indicating overt isolated RV failure.
Collapse
Affiliation(s)
- A Frydrychowicz
- Department of Diagnostic Radiology, University Hospital Freiburg, Germany.
| | | | | | | | | | | | | |
Collapse
|
7
|
Wiesmann F, Ruff J, Engelhardt S, Hein L, Dienesch C, Leupold A, Illinger R, Frydrychowicz A, Hiller KH, Rommel E, Haase A, Lohse MJ, Neubauer S. Dobutamine-stress magnetic resonance microimaging in mice : acute changes of cardiac geometry and function in normal and failing murine hearts. Circ Res 2001; 88:563-9. [PMID: 11282889 DOI: 10.1161/01.res.88.6.563] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The aim of this study was to assess the capability of MRI to characterize systolic and diastolic function in normal and chronically failing mouse hearts in vivo at rest and during inotropic stimulation. Applying an ECG-gated FLASH-cine sequence, MRI at 7 T was performed at rest and after administration of 1.5 microgram/g IP dobutamine. There was a significant increase of heart rate, cardiac output, and ejection fraction and significant decrease of end-diastolic and end-systolic left ventricular (LV) volumes (P<0.01 each) in normal mice during inotropic stimulation. In mice with heart failure due to chronic myocardial infarction (MI), MRI at rest revealed gross LV dilatation. There was a significant decrease of LV ejection fraction in infarcted mice (29%) versus sham mice (58%). Mice with MI showed a significantly reduced maximum LV ejection rate (P<0.001) and LV filling rate (P<0.01) and no increase of LV dynamics during dobutamine action, indicating loss of contractile and relaxation reserve. In 4-month-old transgenic mice with cardiospecific overexpression of the beta(1)-adrenergic receptor, which at this early stage do not show abnormalities of resting cardiac function, LV filling rate failed to increase after dobutamine stress (transgenic, 0.19+/-0.03 microL/ms; wild type, 0.36+/-0.01 microL/ms; P<0.01). Thus, MRI unmasked diastolic dysfunction during dobutamine stress. Dobutamine-stress MRI allows noninvasive assessment of systolic and diastolic components of heart failure. This study shows that MRI can demonstrate loss of inotropic and lusitropic response in mice with MI and can unmask diastolic dysfunction as an early sign of cardiac dysfunction in a transgenic mouse model of heart failure.
Collapse
Affiliation(s)
- F Wiesmann
- Medizinische Universitätsklinik Würzburg, Germany.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Wiesmann F, Ruff J, Dienesch C, Leupold A, Rommel E, Haase A, Neubauer S. Cardiovascular phenotype characterization in mice by high resolution magnetic resonance imaging. MAGMA 2000; 11:10-5. [PMID: 11186973 DOI: 10.1007/bf02678482] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- F Wiesmann
- Medizinische Universitätsklinik Würzburg, Germany.
| | | | | | | | | | | | | |
Collapse
|
9
|
Wiesmann F, Ruff J, Hiller KH, Rommel E, Haase A, Neubauer S. Developmental changes of cardiac function and mass assessed with MRI in neonatal, juvenile, and adult mice. Am J Physiol Heart Circ Physiol 2000; 278:H652-7. [PMID: 10666098 DOI: 10.1152/ajpheart.2000.278.2.h652] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiovascular transgenic mouse models with an early phenotype or even premature death require noninvasive imaging methods that allow for accurate visualization of cardiac morphology and function. Thus the purpose of our study was to assess the feasibility of magnetic resonance imaging (MRI) to characterize cardiac function and mass in newborn, juvenile, and adult mice. Forty-five C57bl/6 mice from seven age groups (3 days to 4 mo after birth) were studied by MRI under isoflurane anesthesia. Electrocardiogram-gated cine MRI was performed with an in-plane resolution of (78-117 microm)(2). Temporal resolution per cine frame was 8.6 ms. MRI revealed cardiac anatomy in mice from all age groups with high temporal and spatial resolution. There was close correlation between MRI- and autopsy-determined left ventricular (LV) mass (r = 0.95, SE of estimate = 9.5 mg). The increase of LV mass (range 9.6-101.3 mg), cardiac output (range 1.1-14.3 ml/min), and stroke volume (range 3. 2-40.2 microl) with age could be quantified by MRI measurements. Ejection fraction and cardiac index did not change with aging. However, LV mass index decreased with increasing age (P < 0.01). High-resolution MRI allows for accurate in vivo assessment of cardiac function in neonatal, juvenile, and adult mice. This method should be useful when applied in transgenic mouse models.
Collapse
Affiliation(s)
- F Wiesmann
- Department of Cardiology, University of Würzburg, 97080 Würzburg, Germany.
| | | | | | | | | | | |
Collapse
|
10
|
Abstract
Chemical shift imaging (CSI) often suffers from the inconvenient shape of its spatial response function (SRF), which affects both localization and signal-to-noise ratio. Replacing the magnetic field gradients for phase encoding by higher order magnetic fields allows a better adjustment of the SRF to the structures in the sample. We combined this principle with the SLOOP (spectral localization with optimal pointspread function) technique to simultaneously obtain spectra from several arbitrarily shaped compartments within a sample. Linear combinations of the fields of the shim coils are used to generate the pulsed fields for phase encoding. Their shapes are matched to the given sample geometry by numerical optimization. Using this method, spectra from a phantom were obtained that show a higher signal-to-noise ratio and a strongly reduced contamination compared to an equivalent CSI experiment.
Collapse
Affiliation(s)
- R Pohmann
- Department of Biophysics, University of Würzburg, Würzburg, Germany
| | | | | |
Collapse
|
11
|
Morgalla MH, Rommel E, Bitzer M, Mettenleiter H, Grote EH. The HanniSetR External Ventricular Pressure Transducer and Drainage System: Experimental and Clinical Evaluation. J Intensive Care Med 1999. [DOI: 10.1046/j.1525-1489.1999.00243.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
12
|
Abstract
Measurement of regional blood volume (RBV) in the myocardium in vivo is important for the assessment of tissue viability and function. The method in this work is based on the acquisition of a T(1) map before and after intravascular contrast agent application. It is known that this method is influenced by perfusion that causes an overestimation of RBV values. In order to solve this problem, the new method is proposed which acquires T(1) maps with slice selective inversion pulses. Due to blood flow nonexcited spins enter the detection slice, which leads to an acceleration of the relaxation time. A model that divides tissue into two compartments is adapted to slice selective inversion in order to derive a simple expression for perfusion-corrected RBV. The aim of the study is to demonstrate the feasibility and accuracy of this technique for quantification of RBV in rat myocardium in vivo. RBV maps were obtained for five rats, and the reproducibility was determined by repeating the experiment several times. A mean RBV value of 12.8 +/- 0.7% (v/v) over all animals was obtained in the myocardium. The results were compared with RBV maps obtained with perfusion-sensitive RBV imaging in the same five rats and with first-pass RBV studies. In order to demonstrate the strength of the new method the vasodilator adenosine was administered and alterations in microcirculation were imaged. Magn Reson Med 42:500-506, 1999.
Collapse
Affiliation(s)
- E Kahler
- Physikalisches Institut, Universität Würzburg, Würzburg, Germany
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Descamps J, Mary A, Rommel E, Anhoury ML, De Neys R, Duchêne M. Release potency tests of hepatitis vaccines. Dev Biol Stand 1999; 101:289-94. [PMID: 10566803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
SmithKline Beecham Biologicals produces two vaccines against hepatitis: hepatitis B (Engerix-B) introduced in 1986 and hepatitis A (Havrix) introduced in 1991. Using these two examples, we demonstrate the long and gradual transition process towards an in vitro release test for potency and a significant decrease in the number of animals needed for vaccine release.
Collapse
Affiliation(s)
- J Descamps
- SmithKline Beecham Biologicals, Rixensart, Belgium
| | | | | | | | | | | |
Collapse
|
14
|
Belle V, Kahler E, Waller C, Rommel E, Voll S, Hiller KH, Bauer WR, Haase A. In vivo quantitative mapping of cardiac perfusion in rats using a noninvasive MR spin-labeling method. J Magn Reson Imaging 1998; 8:1240-5. [PMID: 9848735 DOI: 10.1002/jmri.1880080610] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.8] [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: 11/09/2022] Open
Abstract
Measurement of myocardial perfusion is important for the functional assessment of heart in vivo. Our approach is based on the modification of the longitudinal relaxation time T1 induced by magnetic spin labeling of endogenous water protons. Labeling is performed by selectively inverting the magnetization within the detection slice, and longitudinal relaxation is measured using a fast gradient echo MRI technique. As a result of blood flow, nonexcited spins enter the detection slice, which leads to an acceleration of the relaxation rate. Incorporating this phenomenon in a mathematical model that describes tissue as two compartments yields a simple expression that allows the quantification of perfusion from a slice-selective and a global inversion recovery experiment. This model takes into account the difference between T1 in blood and T1 in tissue. Our purpose was to evaluate the feasibility and reproducibility of this technique to map quantitatively myocardial perfusion in vivo in rats. Quantitative maps of myocardial blood flow were obtained from nine rats, and the reproducibility of the technique was evaluated by repeating the whole perfusion experiment four times. Evaluation of regions of interest within the myocardium yielded a mean perfusion value of 3.6 +/- .5 ml x min(-1) x g(-1) over all animals, which is in good agreement with previously reported literature values.
Collapse
Affiliation(s)
- V Belle
- Physikalisches Institut, Universität Würzburg, Germany
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Kahler E, Waller C, Rommel E, Hiller KH, Voll S, Broich A, Hu K, Schnackerz KD, Bauer WR, Ertl G, Haase A. Quantitative regional blood volume studies in rat myocardium in vivo. Magn Reson Med 1998; 40:517-25. [PMID: 9771568 DOI: 10.1002/mrm.1910400404] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Many pathophysiological processes in the myocardium are in close relation to changes of the regional blood volume and regional myocardial blood flow or perfusion. Only few methods exist to obtain quantitative values for these parameters. Quantitative regional blood volume (RBV) studies in rat myocardium are presented using snapshot fast low angle shot (FLASH) inversion recovery T1 measurements with two different blood pool contrast agents, gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA) albumin and Gd-DTPA polylysine. In contrast to previous attempts, each snapshot FLASH image acquisition was ECG-triggered under breathhold conditions. To measure relaxation times shorter than a heart cycle, each T1 sequence was repeated two times with different delays between inversion pulse and first image acquisition. The experiments were performed on a Bruker Biospec 70/21 using a homogeneous transmitter coil and a circularly polarized surface receiver coil, a special ECG trigger unit, and a respirator that is controlled by the pulse program. Based on a fast exchange model RBVm maps were calculated from the relaxation time maps for different concentrations of the two blood pool contrast agents. A significant dependence of the RBVm values on blood T1 was found. This is in accordance with a model that has been developed recently relating the dependence of RBVm on T1 of blood to perfusion. For Gd-DTPA albumin, the application of the model to the experimental data yields realistic values for RBV and perfusion. The values, which are in accordance with literature data, were obtained at highest contrast agent concentrations i.e., lowest relaxation times of blood (ca. 200 ms).
Collapse
Affiliation(s)
- E Kahler
- Physikalisches Institut, Universität Würzburg, Germany
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Ruff J, Wiesmann F, Hiller KH, Voll S, von Kienlin M, Bauer WR, Rommel E, Neubauer S, Haase A. Magnetic resonance microimaging for noninvasive quantification of myocardial function and mass in the mouse. Magn Reson Med 1998; 40:43-8. [PMID: 9660551 DOI: 10.1002/mrm.1910400106] [Citation(s) in RCA: 148] [Impact Index Per Article: 5.7] [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: 11/10/2022]
Abstract
The purpose of this work was to develop high-resolution cardiac magnetic resonance imaging techniques for the in vivo mouse model for quantification of myocardial function and mass. Eight male mice were investigated on a 7-Tesla MRI scanner. High-quality images in multiple short axis slices (in-plane resolution 117 microm2, slice thickness 1 mm) were acquired with an ECG-gated cine sequence. Left ventricular end-diastolic and end-systolic volumes and mass were calculated from segmented slice volumes. There was precise agreement of left ventricular mass determined ex vivo and by MRI. Intraobserver (5%) and interobserver (5%) variability of in vivo MR measurements were low.
Collapse
Affiliation(s)
- J Ruff
- Physikalisches Institut (EP5), Universität Würzburg, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Bauer WR, Roder F, Hiller KH, Han H, Fröhlich S, Rommel E, Haase A, Ertl G. The effect of perfusion on T1 after slice-selective spin inversion in the isolated cardioplegic rat heart: measurement of a lower bound of intracapillary-extravascular water proton exchange rate. Magn Reson Med 1997; 38:917-23. [PMID: 9402192 DOI: 10.1002/mrm.1910380610] [Citation(s) in RCA: 43] [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: 02/05/2023]
Abstract
Many NMR measurements of cardiac microcirculation (perfusion, intramyocardial blood volume) depend on some kind of assumption of intracapillary-extravascular water exchange rate, e.g., fast exchange. The magnitude of this water exchange rate, however, is still unknown. The intention of this study was to determine a lower limit for this exchange rate by investigating the effect of perfusion on relaxation time. Studies were performed in the isolated perfused cardioplegic rat heart. After slice-selective inversion, the spin lattice relaxation rate of myocardium within the slice was studied as a function of perfusion and compared with a mathematical model which predicts relaxation rate as a function of perfusion and intracapillary-extravascular exchange rate. A linear relationship was found between relaxation rate T(-1) and perfusion P normalized by perfusate/tissue partition coefficient of water, lambda: deltaT(-1) = m x deltaP/lambda with 0.82 < or = m < or = 1.06. Insertion of experimental data in the model revealed that a lower bound of the exchange rate from intra- to extravascular space is 6.6 s(-1) (4.5 s(-1), P < 0.05), i.e., the intracapillary lifetime of a water molecule is less than 150 ms (222 ms, P < 0.05). Based on this finding, the T1 mapping after slice-selective inversion could become a valuable noncontrast NMR method to measure variations of perfusion.
Collapse
Affiliation(s)
- W R Bauer
- II. Medizinische Universitätsklinik Mannheim/Heidelberg, Germany
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Bauer W, Hiller KH, Roder F, Rommel E, Gaudron P, Hu K, Broich A, Neubauer S, Haase A, Ertl G. Sequential noninvasive measurement of relative blood volumein surviving myocardium of infarcted rat hearts: A NMR-relaxometry study in intact animals. J Am Coll Cardiol 1996. [DOI: 10.1016/s0735-1097(96)82474-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
19
|
Bauer WR, Hiller KH, Roder F, Rommel E, Ertl G, Haase A. Magnetization exchange in capillaries by microcirculation affects diffusion-controlled spin-relaxation: a model which describes the effect of perfusion on relaxation enhancement by intravascular contrast agents. Magn Reson Med 1996; 35:43-55. [PMID: 8771021 DOI: 10.1002/mrm.1910350107] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The effect of perfusion on relaxation time in tissue has only been considered for first-pass kinetics of NMR-signal after application of contrast agents. The importance of perfusion on relaxation has not yet been studied for steady state conditions, i.e., when the intravascular relaxation rate is constant in time. The aim of this study is to develop a model in which T1 relaxation is derived as a function of perfusion and intracapillary volume fraction (regional blood volume). Tissue is considered to be two-compartment system, which consists of intracapillary and extravascular space. Intracapillary relaxation differs from relaxation in the arterial system due to diffusion-exchange of magnetization from extravascular to intracapillary space. Perfusion tends to attenuate this difference and thus counteracts the effect on intracapillary relaxation. Relaxation in the extravascular and intracapillary magnetization are linked by diffusion. This dependence is presented in analytical form and a generic equation is derived. AT1 experiment is considered in which all spins of tissue and blood are inverted at the beginning. Calculations are performed for the fast exchange model of tissue. Perfusion increases relaxation enhancement of intravascular contrast agents. This effect is considerable in highly perfused tissue like myocardium. The dependence of relaxation on perfusion implies an overestimation of the regional blood volume when the calculation of the latter is based on tissue models that neglect perfusion. The model presented here is applied to predict the effect of perfusion on T1 imaging with FLASH-pulse sequences because this technique has been proven to be a powerful method to obtain T1 maps within a short time interval. For the fast exchange model, two algorithms are suggested that determine perfusion and regional blood volume from T1 imaging in the presence and absence of intravascular contrast agents.
Collapse
Affiliation(s)
- W R Bauer
- Medizinische Universitätsklinik Würzburg, Germany
| | | | | | | | | | | |
Collapse
|
20
|
Hirunagi K, Rommel E, Korf HW. Ultrastructure of cerebrospinal fluid-contacting neurons immunoreactive to vasoactive intestinal peptide and properties of the blood-brain barrier in the lateral septal organ of the duck. Cell Tissue Res 1995; 279:123-33. [PMID: 7895253 DOI: 10.1007/bf00300699] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Immuno-electron-microscopic investigations of cerebrospinal fluid (CSF)-contacting neurons immunoreactive to vasoactive intestinal peptide in the duck lateral septum have revealed that this cell type gives rise to an adventricular dendrite terminating with a bulbous swelling in the lateral ventricle. The swelling bears a cilium and contains mitochondria and immunolabeled dense-core vesicles. Two types of processes emerge from the basal part of the perikaryon. The first has a large diameter, contains diffusely distributed immunoreaction, and receives synaptic input, indicating that this process is a basal dendrite. The other type is of a beaded appearance, displays immunolabeled dense-core vesicles, and represents the axon of the CSF-contacting neuron. VIP-immunoreactive terminal formations are located within the neuropil of the lateral septum and the nucleus accumbens. Some of them form synaptic contacts with immunonegative profiles. No VIP-immunoreactive terminal formations are seen in the perivascular spaces of the lateral septum. Tracer experiments with horseradish peroxidase have revealed that the blood-brain barrier is lacking in the lateral septal organ and nucleus accumbens of the duck. Capillaries, arterioles, and venoles of this region are coated by nonfenestrated endothelial cells connected by "leaky" junctions, allowing the tracer to penetrate from the lumen into the perivascular space and further into the intercellular clefts of the neuropil. Our immuno-electron-microscopic investigations show that VIP-immunoreactive CSF-contacting neurons of the lateral septum closely resemble CSF-contacting neurons occurring in other brain regions, e.g., the hypothalamus. The arrangement of VIP-immunoreactive terminal formations suggests that, in the lateral septum, the VIP-like neuropeptide serves as a neurotransmitter (-modulator). The lack of a blood-brain barrier in the lateral septal organ and the nucleus accumbens raises the possibility that this region is a window in the avian brain allowing exchange of information between the central nervous system and the bloodstream; it thus resembles a circumventricular organ.
Collapse
Affiliation(s)
- K Hirunagi
- Center of Morphology, Section Neurobiology, Johann Wolfgang Goethe University Frankfurt, Germany
| | | | | |
Collapse
|
21
|
Hirunagi K, Rommel E, Oksche A, Korf HW. Vasoactive intestinal peptide-immunoreactive cerebrospinal fluid-contacting neurons in the reptilian lateral septum/nucleus accumbens. Cell Tissue Res 1993; 274:79-90. [PMID: 8242714 DOI: 10.1007/bf00327988] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
By means of immunocytochemical demonstration of vasoactive intestinal peptide (VIP) an accumulation of cerebrospinal fluid (CSF)-contacting neurons was found in a circumscribed region of the nucleus accumbens/lateral septum of eleven reptilian (chelonian, lacertilian, ophidian, crocodilian) species. Basal processes of these cells contribute to a subependymal plexus whose density displays considerable interspecific variation. VIP-immunoreactive nerve fibers occur also in the lateral septum and the nucleus accumbens where they encompass immunonegative cells in a basket-like pattern. The CSF-contacting neurons are surrounded by columnar ependymocytes frequently arranged in a pseudostratified manner. These specialized arrays of ependymal cells, however, occupy a more extended area than the VIP-immunoreactive CSF-contacting neurons and can be traced from the rostro-ventral pole of the lateral ventricle to the interventricular foramen. These observations suggest the existence of a telencephalic site of CSF-contacting neurons which may be more widespread than hitherto thought and which may participate in a circumventricular system of the lateral ventricle. Previous studies mainly performed with birds indicate that the VIP-immunoreactive CSF-contacting neurons of the nucleus accumbens might form a part of the "encephalic" (extraretinal and extrapineal) photoreceptor. However, further experiments are required to test this supposition since the VIP-immunoreactive neurons of the nucleus accumbens remained unlabeled by antibodies against bovine rodopsin and chicken cone-opsin in all eleven species analysed in this investigation.
Collapse
Affiliation(s)
- K Hirunagi
- Center of Morphology, Johann Wolfgang Goethe University Frankfurt, Germany
| | | | | | | |
Collapse
|
22
|
Rommel E, Kimmich R, Körperich H, Kunze C, Gersonde K. T1 rho dispersion imaging and localized T1 rho dispersion relaxometry: application in vivo to mouse adenocarcinoma. Magn Reson Med 1992; 24:149-57. [PMID: 1556921 DOI: 10.1002/mrm.1910240115] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The dispersion (frequency dependence) of the spin-lattice relaxation time in the rotating frame, T1 rho, is considered for tissue characterization. Methods for the volume-selective determination of the proper T1 rho dispersion and for imaging of parameters characterizing this frequency dependence are described. On- and off-resonance versions of the techniques are demonstrated. In vitro studies of excised rat tissues and in vivo applications to mice with implanted adenocarcinoma are reported. T1 rho dispersion images show clear contrasts of the malignant tissue, whereas muscle tissue is completely suppressed. No contrast agent is required. The measuring time is only twice as long as that for conventional magnetic resonance images. The results suggest that the T1 rho dispersion is less susceptible to the biological variability than the absolute values of the relaxation times.
Collapse
Affiliation(s)
- E Rommel
- Sektion Kernresonanzspektroskopie, Universität Ulm, Federal Republic of Germany
| | | | | | | | | |
Collapse
|
23
|
Abstract
Pure nuclear quadrupole resonance (NQR) was combined with a rotating-frame imaging technique (rho NQRI). The method is suitable for powdery or crystalline materials containing quadrupole nuclei. The spatial information is encoded in the amplitudes of the free-induction decays (FIDs) by gradients of the radio frequency amplitude of the excitation pulse. The pulse length is incremented in a series of experiments so that a pseudo-FID can be formed from the intensities of a selected NQR line. A deconvolution procedure is used for the analysis of the pseudo-FIDs. The result is a sample profile along the gradient direction. The technique is particularly suitable for the detection of the spatial distribution of physical parameters producing NQR line shifts. Examples are stress or temperature. Two-dimensional images can be produced by rotating the sample step by step. For each orientation a profile across the sample is evaluated. A backprojection reconstruction formalism then permits the rendering of two-dimensional NQR images.
Collapse
Affiliation(s)
- R Kimmich
- Sektion Kernresonanzspektroskopie, Universität Ulm, Germany
| | | | | |
Collapse
|
24
|
|
25
|
Kimmich R, Unrath W, Schnur G, Rommel E. NMR measurement of small self-diffusion coefficients in the fringe field of superconducting magnets. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0022-2364(91)90416-q] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
26
|
|
27
|
Abstract
Pulse sequences which permit imaging and volume-selective determination of parameters characterizing the frequency dependence of the spin-lattice relaxation time in the rotating frame, T1 rho, are presented. The contrasts are due to slowly moving macromolecules or paramagnetic contrast agents. In vivo test experiments were carried out with tumorous mice treated with a contrast agent. It is shown that the contrast effect is dramatically enhanced in T1 rho dispersion images compared with images weighted by any of the relaxation times.
Collapse
Affiliation(s)
- E Rommel
- Sektion Kernresonanzspektroskopie, Universität Ulm, Federal Republic of Germany
| | | |
Collapse
|
28
|
Abstract
A method for the volume- and resonance line-selective determination of the longitudinal relaxation time in the rotating frame, T1 rho, is described. The spin-lock pulse intrinsic to the T1 rho sequence simultaneously replaces the first slice-selective pulse of the VOSY method for localized spectroscopy. This is a further parameter suitable for the local characterization of tissue. On the same basis, T1 rho can be used as a new contrast parameter for biomedical imaging purposes. An appropriate pulse sequence for T1 rho imaging is presented. Test experiments which promise some striking advantages compared with conventional magnetic resonance imaging are reported.
Collapse
Affiliation(s)
- E Rommel
- Sektion Kernresonanzspektroskopie, Universität Ulm, Federal Republic of Germany
| | | |
Collapse
|
29
|
|
30
|
Knüttel A, Rommel E, Clausen M, Kimmich R. Integrated volume-selective/spectral editing 1H NMR and postdetection signal processing for the sensitive determination of lactate. Magn Reson Med 1988; 8:70-9. [PMID: 3173070 DOI: 10.1002/mrm.1910080108] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A new volume selection/spectral editing pulse sequence (VOSING) is presented. The features specific to the technique are that the volume selection and the editing intervals coincide and that no decoupling is necessary. The pulse sequence can be applied under both homo- and heteronuclear conditions. Phantom experiments with lactate solutions and human serum led to water suppression factors of about 20,000. A postdetection signal processing method has been implemented. The final sensitivity for lactate determinations could thus be improved by a factor of more than 4. Ischemia-induced lactate could easily be detected in serum. At present, the lower detection limit of lactate is 1 mmol/liter for a (1.2 cm)3 voxel and 32 scans in a 4.7-T/40-cm magnet.
Collapse
Affiliation(s)
- A Knüttel
- Universität Ulm, Sektion Kernresonanzspektroskopie, Federal Republic of Germany
| | | | | | | |
Collapse
|
31
|
Eenaeme C, Evrard P, Istasse L, Rommel E, Baldwin P, Gielen M, Maghuin-Rogister G, Bienfait JM. Attempt to growth stimulation by vaccination against somatostatin and anabolisation with trenbolone oestradiol in young bulls. J Anim Physiol Anim Nutr (Berl) 1988. [DOI: 10.1111/j.1439-0396.1988.tb00045.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
32
|
Kühner W, Rommel E, Noack F, Meier P. Proton Spin Relaxation Study of Molecular Motions in the Lyotropic Liquid Crystalline System Potassium-Laurate Water. ACTA ACUST UNITED AC 1987. [DOI: 10.1515/zna-1987-0204] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The paper presents and discusses measurements of the proton spin T1 relaxation dispersion over a broad frequency range (100 Hz - 300 MHz) in the micellar, hexagonal, cubic and lamellar phases of lyotropic potassium-laurate water mixtures. The results clearly show that in the anisotropic phases (hexagonal, lamellar) T1 at low Larmor frequencies is dominated by liquid crystalline order fluctuations, whereas this relaxation mechanism is negligible or absent in the isotropic phases (micellar, cubic). At medium and high Larmor frequencies the relaxation reflects rotational and translational molecular motions. Using theoretical models from the literature for the three kinds of reorientations the observed frequency and temperature dependences of T1 can be described quantitatively. In contrast to the order fluctuation mechanism the rotational and translational reorientations of individual molecules depend only weakly on the mesogenic structure. The order fluctuation contribution is strongest for the lamellar phase.
Collapse
Affiliation(s)
- W. Kühner
- 1Physikalisches Institut der Universität Stuttgart
| | - E. Rommel
- 1Physikalisches Institut der Universität Stuttgart
| | - F. Noack
- 1Physikalisches Institut der Universität Stuttgart
| | - P. Meier
- 2Institut für Physikalische Chemie der Universität Stuttgart
| |
Collapse
|
33
|
Rommel E, Mischker K, Osswald G, Schweikert K, Noack F. A powerful NMR field-cycling device using GTOs and MOSFETs for relaxation dispersion and zero-field studies. ACTA ACUST UNITED AC 1986. [DOI: 10.1016/0022-2364(86)90004-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|