14260
2011
eng
e18386
4
6
article
1
2017-01-10
--
--
Sustained Reperfusion after Blockade of Glycoprotein-Receptor-Ib in Focal Cerebral Ischemia: An MRI Study at 17.6 Tesla
Background:
Inhibition of early platelet adhesion by blockade of glycoprotein-IB (GPIb) protects mice from ischemic stroke. To elucidate underlying mechanisms in-vivo, infarct development was followed by ultra-high field MRI at 17.6 Tesla.
Methods:
Cerebral infarction was induced by transient-middle-cerebral-artery-occlusion (tMCAO) for 1 hour in C57/BL6 control mice (N = 10) and mice treated with 100 mg Fab-fragments of the GPIb blocking antibody p0p/B 1 h after tMCAO (N = 10). To control for the effect of reperfusion, additional mice underwent permanent occlusion and received anti-GPIb treatment (N = 6; pMCAO) or remained without treatment (N = 3; pMCAO). MRI 2 h and 24 h after MCAO measured cerebral-blood-flow (CBF) by continuous arterial-spin labelling, the apparent-diffusion-coefficient (ADC), quantitative-T2 and T2-weighted imaging. All images were registered to a standard mouse brain MRI atlas and statistically analysed voxel-wise, and by cortico-subcortical ROI analysis.
Results:
Anti-GPIb treatment led to a relative increase of postischemic CBF vs. controls in the cortical territory of the MCA (2 h: 44.2 +/- 6.9 ml/100g/min versus 24 h: 60.5 +/- 8.4; p = 0.0012, F((1,18)) = 14.63) after tMCAO. Subcortical CBF 2 h after tMCAO was higher in anti-GPIb treated animals (45.3 +/- 5.9 vs. controls: 33.6 +/- 4.3; p = 0.04). In both regions, CBF findings were clearly related to a lower probability of infarction (Cortex/Subcortex of treated group: 35%/65% vs. controls: 95%/100%) and improved quantitative-T2 and ADC. After pMCAO, anti-GPIb treated mice developed similar infarcts preceded by severe irreversible hypoperfusion as controls after tMCAO indicating dependency of stroke protection on reperfusion.
Conclusion:
Blockade of platelet adhesion by anti-GPIb-Fab-fragments results in substantially improved CBF early during reperfusion. This finding was in exact spatial correspondence with the prevention of cerebral infarction and indicates in-vivo an increased patency of the microcirculation. Thus, progression of infarction during early ischemia and reperfusion can be mitigated by anti-platelet treatment.
PLoS ONE
10.1371/journal.pone.0018386
urn:nbn:de:bvb:20-opus-142608
PLoS ONE 6(4): e18386. doi:10.1371/journal.pone.0018386
Mirko Pham
Xavier Helluy
Christoph Kleinschnitz
Peter Kraft
Andreas J. Bartsch
Peter Jakob
Bernhard Nieswandt
Martin Bendszus
Stoll Guido
eng
uncontrolled
Von-Willebrand-factor
eng
uncontrolled
Experimental stroke
eng
uncontrolled
Magnetic-resonance
eng
uncontrolled
Arterial water
eng
uncontrolled
Brain
eng
uncontrolled
Perfusion
eng
uncontrolled
Mice
eng
uncontrolled
Inflammation
eng
uncontrolled
Coefficient
eng
uncontrolled
mechanisms
Krankheiten
open_access
Physikalisches Institut
Neurologische Klinik und Poliklinik
Rudolf-Virchow-Zentrum
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/files/14260/134_Pham_PLOS-ONE.pdf
13834
2015
eng
e0141894
11
10
article
1
2016-09-14
--
--
Microstructural Analysis of Peripheral Lung Tissue through CPMG Inter-Echo Time R2 Dispersion
Since changes in lung microstructure are important indicators for (early stage) lung pathology, there is a need for quantifiable information of diagnostically challenging cases in a clinical setting, e.g. to evaluate early emphysematous changes in peripheral lung tissue. Considering alveoli as spherical air-spaces surrounded by a thin film of lung tissue allows deriving an expression for Carr-Purcell-Meiboom-Gill transverse relaxation rates R-2 with a dependence on inter-echo time, local air-tissue volume fraction, diffusion coefficient and alveolar diameter, within a weak field approximation. The model relaxation rate exhibits the same hyperbolic tangent dependency as seen in the Luz-Meiboom model and limiting cases agree with Brooks et al. and Jensen et al. In addition, the model is tested against experimental data for passively deflated rat lungs: the resulting mean alveolar radius of RA = 31.46 \(\pm\) 13.15 \(\mu\)m is very close to the literature value (similar to 34 \(\mu\)m). Also, modeled radii obtained from relaxometer measurements of ageing hydrogel foam (that mimics peripheral lung tissue) are in good agreement with those obtained from mu CT images of the same foam (mean relative error: 0.06 \(\pm\) 0.01). The model's ability to determine the alveolar radius and/or air volume fraction will be useful in quantifying peripheral lung microstructure.
PLoS One
10.1371/journal.pone.0141894
urn:nbn:de:bvb:20-opus-138345
PLoS ONE 10(11): e0141894. doi:10.1371/journal.pone.0141894
Felix T. Kurz
Thomas Kampf
Lukas R. Buschle
Heinz-Peter Schlemmer
Sabine Heiland
Martin Bendszus
Christian H. Ziener
eng
uncontrolled
transverse relaxation
eng
uncontrolled
number
eng
uncontrolled
HE-3 diffusion MRI
eng
uncontrolled
magnetic-resonance behavior
eng
uncontrolled
hyperpolarized HE-3
eng
uncontrolled
Bessle functions
eng
uncontrolled
self-diffusion
eng
uncontrolled
alveolar
eng
uncontrolled
field
eng
uncontrolled
morphometry
Krankheiten
open_access
Physikalisches Institut
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/files/13834/asset1.pdf
19060
2016
eng
4
article
1
--
2016-12-02
--
Generalized moment analysis of magnetic field correlations for accumulations of spherical and cylindrical magnetic perturbers
In biological tissue, an accumulation of similarly shaped objects with a susceptibility difference to the surrounding tissue generates a local distortion of the external magnetic field in magnetic resonance imaging. It induces stochastic field fluctuations that characteristically influence proton spin dephasing in the vicinity of these magnetic perturbers. The magnetic field correlation that is associated with such local magnetic field inhomogeneities can be expressed in the form of a dynamic frequency autocorrelation function that is related to the time evolution of the measured magnetization. Here, an eigenfunction expansion for two simple magnetic perturber shapes, that of spheres and cylinders, is considered for restricted spin diffusion in a simple model geometry. Then, the concept of generalized moment analysis, an approximation technique that is applied in the study of (non-)reactive processes that involve Brownian motion, allows deriving analytical expressions of the correlation function for different exponential decay forms. Results for the biexponential decay for both spherical and cylindrical magnetized objects are derived and compared with the frequently used (less accurate) monoexponential decay forms. They are in asymptotic agreement with the numerically exact value of the correlation function for long and short times.
Frontiers in Physics
2296-424X
10.3389/fphy.2016.00046
urn:nbn:de:bvb:20-opus-190604
Frontiers in Physics 2016, 4:46. doi: 10.3389/fphy.2016.00046
true
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Felix T. Kurz
Thomas Kampf
Lukas R. Buschle
Heinz-Peter Schlemmer
Martin Bendszus
Sabine Heiland
Christian H. Ziener
eng
uncontrolled
magnetized sphere/cylinder
eng
uncontrolled
magnetic susceptibility
eng
uncontrolled
correlation function
eng
uncontrolled
diffusion
eng
uncontrolled
magnetic resonance imaging
Physik
open_access
Physikalisches Institut
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/files/19060/fphy-04-00046.pdf
16743
2016
eng
e1005470
3
12
article
1
2018-08-27
--
--
Experimental Cerebral Malaria Spreads along the Rostral Migratory Stream
It is poorly understood how progressive brain swelling in experimental cerebral malaria (ECM) evolves in space and over time, and whether mechanisms of inflammation or microvascular sequestration/obstruction dominate the underlying pathophysiology. We therefore monitored in the Plasmodium berghei ANKA-C57BL/6 murine ECM model, disease manifestation and progression clinically, assessed by the Rapid-Murine-Coma-and-Behavioral-Scale (RMCBS), and by high-resolution in vivo MRI, including sensitive assessment of early blood-brain-barrier-disruption (BBBD), brain edema and microvascular pathology. For histological correlation HE and immunohistochemical staining for microglia and neuroblasts were obtained. Our results demonstrate that BBBD and edema initiated in the olfactory bulb (OB) and spread along the rostral-migratory-stream (RMS) to the subventricular zone of the lateral ventricles, the dorsal-migratory-stream (DMS), and finally to the external capsule (EC) and brainstem (BS). Before clinical symptoms (mean RMCBS = 18.5±1) became evident, a slight, non-significant increase of quantitative T2 and ADC values was observed in OB+RMS. With clinical manifestation (mean RMCBS = 14.2±0.4), T2 and ADC values significantly increased along the OB+RMS (p = 0.049/p = 0.01). Severe ECM (mean RMCBS = 5±2.9) was defined by further spread into more posterior and deeper brain structures until reaching the BS (significant T2 elevation in DMS+EC+BS (p = 0.034)). Quantitative automated histological analyses confirmed microglial activation in areas of BBBD and edema. Activated microglia were closely associated with the RMS and neuroblasts within the RMS were severely misaligned with respect to their physiological linear migration pattern. Microvascular pathology and ischemic brain injury occurred only secondarily, after vasogenic edema formation and were both associated less with clinical severity and the temporal course of ECM. Altogether, we identified a distinct spatiotemporal pattern of microglial activation in ECM involving primarily the OB+RMS axis, a distinct pathway utilized by neuroblasts and immune cells. Our data suggest significant crosstalk between these two cell populations to be operative in deeper brain infiltration and further imply that the manifestation and progression of cerebral malaria may depend on brain areas otherwise serving neurogenesis.
PLoS Pathogens
10.1371/journal.ppat.1005470
urn:nbn:de:bvb:20-opus-167434
PLoS Pathogens 12(3):e1005470 (2016). DOI: 10.1371/journal.ppat.1005470
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Angelika Hoffmann
Johannes Pfeil
Julieta Alfonso
Felix T. Kurz
Felix Sahm
Sabine Heiland
Hannah Monyer
Martin Bendszus
Ann-Kristin Mueller
Xavier Helluy
Mirko Pham
eng
uncontrolled
experimental cerebral malaria
eng
uncontrolled
rostral-migratory-stream
eng
uncontrolled
brain swelling
Medizin und Gesundheit
open_access
Fakultät für Physik und Astronomie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/files/16743/Hoffmann_PLoS_PATHOGENS.PDF
21245
2020
eng
14
article
1
--
--
--
Diabetic Polyneuropathy Is Associated With Pathomorphological Changes in Human Dorsal Root Ganglia: A Study Using 3T MR Neurography
Diabetic neuropathy (DPN) is one of the most severe and yet most poorly understood complications of diabetes mellitus. In vivo imaging of dorsal root ganglia (DRG), a key structure for the understanding of DPN, has been restricted to animal studies. These have shown a correlation of decreased DRG volume with neuropathic symptom severity. Our objective was to investigate correlations of DRG morphology and signal characteristics at 3 Tesla (3T) magnetic resonance neurography (MRN) with clinical and serological data in diabetic patients with and without DPN. In this cross-sectional study, participants underwent 3T MRN of both L5 DRG using an isotropic 3D T2-weighted, fat-suppressed sequence with subsequent segmentation of DRG volume and analysis of normalized signal properties. Overall, 55 diabetes patients (66 ± 9 years; 32 men; 30 with DPN) took part in this study. DRG volume was smaller in patients with severe DPN when compared to patients with mild or moderate DPN (134.7 ± 21.86 vs 170.1 ± 49.22; p = 0.040). In DPN patients, DRG volume was negatively correlated with the neuropathy disability score (r = −0.43; 95%CI = −0.66 to −0.14; p = 0.02), a measure of neuropathy severity. DRG volume showed negative correlations with triglycerides (r = −0.40; 95%CI = −0.57 to −0.19; p = 0.006), and LDL cholesterol (r = −0.33; 95%CI = −0.51 to −0.11; p = 0.04). There was a strong positive correlation of normalized MR signal intensity (SI) with the neuropathy symptom score in the subgroup of patients with painful DPN (r = 0.80; 95%CI = 0.46 to 0.93; p = 0.005). DRG SI was positively correlated with HbA1c levels (r = 0.30; 95%CI = 0.09 to 0.50; p = 0.03) and the triglyceride/HDL ratio (r = 0.40; 95%CI = 0.19 to 0.57; p = 0.007). In this first in vivo study, we found DRG morphological degeneration and signal increase in correlation with neuropathy severity. This elucidates the potential importance of MR-based DRG assessments in studying structural and functional changes in DPN.
Frontiers in Neuroscience
10.3389/fnins.2020.570744
urn:nbn:de:bvb:20-opus-212459
swordwue
2020-10-01T19:52:37+00:00
attachment; filename=deposit.zip
d31996ce6a428ff2f5a34862fbadcfe2
Frontiers in Neuroscience 2020, 14:570744. DOI: 10.3389/fnins.2020.570744
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Johann M. E. Jende
Zoltan Kender
Christian Rother
Lucia Alvarez-Ramos
Jan B. Groener
Mirko Pham
Jakob Morgenstern
Dimitrios Oikonomou
Artur Hahn
Alexander Juerchott
Jennifer Kollmer
Sabine Heiland
Stefan Kopf
Peter P. Nawroth
Martin Bendszus
Felix T. Kurz
eng
uncontrolled
diabetic polyneuropathy
eng
uncontrolled
dorsal root ganglion
eng
uncontrolled
magnetic resonance neurography
eng
uncontrolled
neuropathic pain
eng
uncontrolled
peripheral nervous system
Medizin und Gesundheit
open_access
Institut für diagnostische und interventionelle Neuroradiologie (ehem. Abteilung für Neuroradiologie)
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/files/21245/fnins-14-570744.pdf