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Tessa Geelen

Bio: Tessa Geelen is an academic researcher from Eindhoven University of Technology. The author has contributed to research in topics: Liposome & In vivo. The author has an hindex of 12, co-authored 14 publications receiving 463 citations.

Papers
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Journal ArticleDOI
TL;DR: The in vivo use of targeted paramagnetic liposomes has facilitated the specific imaging of pathophysiological processes, such as angiogenesis and inflammation, and MR image‐guided drug delivery using such liposome allows the visualization and quantification of local drug delivery.
Abstract: Liposomes are a versatile class of nanoparticles with tunable properties, and multiple liposomal drug formulations have been clinically approved for cancer treatment. In recent years, an extensive library of gadolinium (Gd)containing liposomal MRI contrast agents has been developed for molecular and cellular imaging of disease-specific markers and for image-guided drug delivery. This review discusses the advances in the development and novel applications of paramagnetic liposomes in molecular and cellular imaging, and in image-guided drug delivery. A high targeting specificity has been achieved in vitro using ligand-conjugated paramagnetic liposomes. On targeting of internalizing cell receptors, the effective longitudinal relaxivity r1 of paramagnetic liposomes is modulated by compartmentalization effects. This provides unique opportunities to monitor the biological fate of liposomes. In vivo contrast-enhanced MRI studies with nontargeted liposomes have shown the extravasation of liposomes in diseases associated with endothelial dysfunction, such as tumors and myocardial infarction. The in vivo use of targeted paramagnetic liposomes has facilitated the specific imaging of pathophysiological processes, such as angiogenesis and inflammation. Paramagnetic liposomes loaded with drugs have been utilized for therapeutic interventions. MR image-guided drug delivery using such liposomes allows the visualization and quantification of local drug delivery. Copyright © 2013 John Wiley & Sons, Ltd.

90 citations

Journal ArticleDOI
TL;DR: In this article, the distribution pattern of differently sized long-circulating lipid-based nanoparticles, namely micelles (~15 nm) and liposomes (~100 nm), in a mouse model of myocardial infarction was characterized.

69 citations

Journal ArticleDOI
TL;DR: This liposomal contrast agent displays great potential for in vivo MRI of inflammation-related ICAM-1 expression, and had a high longitudinal and transversal relaxivity, which enabled differentiation between basal and upregulated levels of ICAM -1 expression by MRI.
Abstract: Background: The upregulation of intercellular adhesion molecule-1 (ICAM-1) on the endothelium of blood vessels in response to pro-inflammatory stimuli is of major importance for the regulation of local inflammation in cardiovascular diseases such as atherosclerosis, myocardial infarction and stroke. In vivo molecular imaging of ICAM-1 will improve diagnosis and follow-up of patients by non-invasive monitoring of the progression of inflammation. Results: A paramagnetic liposomal contrast agent functionalized with anti-ICAM-1 antibodies for multimodal magnetic resonance imaging (MRI) and fluorescence imaging of endothelial ICAM-1 expression is presented. The ICAM-1-targeted liposomes were extensively characterized in terms of size, morphology, relaxivity and the ability for binding to ICAM-1-expressing endothelial cells in vitro. ICAM-1-targeted liposomes exhibited strong binding to endothelial cells that depended on both the ICAM-1 expression level and the concentration of liposomes. The liposomes had a high longitudinal and transversal relaxivity, which enabled differentiation between basal and upregulated levels of ICAM-1 expression by MRI. The liposome affinity for ICAM-1 was preserved in the competing presence of leukocytes and under physiological flow conditions. Conclusion: This liposomal contrast agent displays great potential for in vivo MRI of inflammation-related ICAM-1 expression.

67 citations

Journal ArticleDOI
TL;DR: This study shows that 3D T1 mapping in the mouse heart is feasible and can be used to monitor regional changes in myocardial T1, particularly in relation to pathology and in contrast‐enhanced experiments to estimate local concentrations of (targeted) contrast agent.
Abstract: Cardiac MR T(1) mapping is a promising quantitative imaging tool for the diagnosis and evaluation of cardiomyopathy. Here, we present a new preclinical cardiac MRI method enabling three-dimensional T(1) mapping of the mouse heart. The method is based on a variable flip angle analysis of steady-state MR imaging data. A retrospectively triggered three-dimensional FLASH (fast low-angle shot) sequence (3D IntraGate) enables a constant repetition time and maintains steady-state conditions. 3D T(1) mapping of the complete mouse heart could be achieved in 20 min. High-quality, bright-blood T(1) maps were obtained with homogeneous T(1) values (1764 ± 172 ms) throughout the myocardium. The repeatability coefficient of R(1) (1/T(1) ) in a specific region of the mouse heart was between 0.14 and 0.20 s(-1) , depending on the number of flip angles. The feasibility for detecting regional differences in ΔR(1) was shown with pre- and post-contrast T(1) mapping in mice with surgically induced myocardial infarction, for which ΔR(1) values up to 0.83 s(-1) were found in the infarct zone. The sequence was also investigated in black-blood mode, which, interestingly, showed a strong decrease in the apparent mean T(1) of healthy myocardium (905 ± 110 ms). This study shows that 3D T(1) mapping in the mouse heart is feasible and can be used to monitor regional changes in myocardial T(1), particularly in relation to pathology and in contrast-enhanced experiments to estimate local concentrations of (targeted) contrast agent.

60 citations

Journal ArticleDOI
TL;DR: A first‐pass myocardial perfusion sequence for mouse cardiac MRI is presented, using a segmented ECG‐triggered acquisition combined with parallel imaging acceleration to capture the first pass of a Gd‐DTPA bolus through the mouse heart with a temporal resolution of 300–400 msec.
Abstract: A first-pass myocardial perfusion sequence for mouse cardiac MRI is presented A segmented ECG-triggered acquisition combined with parallel imaging acceleration was used to capture the first pass of a Gd-DTPA bolus through the mouse heart with a temporal resolution of 300–400 msec The method was applied in healthy mice (N = 5) and in mice with permanent occlusion of the left coronary artery (N = 6) Baseline semiquantitative perfusion values of healthy myocardium showed excellent reproducibility Infarct regions revealed a significant decrease in the semiquantitative myocardial perfusion values (005 ± 002) compared to remote myocardium (020 ± 004) Myocardial areas of decreased perfusion correlated well to infarct areas identified on the delayed-enhancement scans This protocol is a valuable addition to the mouse cardiac MRI toolbox for preclinical studies of ischemic heart disease Magn Reson Med, 2010 © 2010 Wiley-Liss, Inc

42 citations


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TL;DR: This work addresses the physicochemical makeup/design of nanomaterials through the lens of the physical properties that produce contrast signal for the cognate imaging modality-the authors stratify nanommaterials on the basis of their (i) magnetic, (ii) optical, (iii) acoustic, and/or nuclear properties.
Abstract: In vivo imaging, which enables us to peer deeply within living subjects, is producing tremendous opportunities both for clinical diagnostics and as a research tool. Contrast material is often required to clearly visualize the functional architecture of physiological structures. Recent advances in nanomaterials are becoming pivotal to generate the high-resolution, high-contrast images needed for accurate, precision diagnostics. Nanomaterials are playing major roles in imaging by delivering large imaging payloads, yielding improved sensitivity, multiplexing capacity, and modularity of design. Indeed, for several imaging modalities, nanomaterials are now not simply ancillary contrast entities, but are instead the original and sole source of image signal that make possible the modality’s existence. We address the physicochemical makeup/design of nanomaterials through the lens of the physical properties that produce contrast signal for the cognate imaging modality—we stratify nanomaterials on the basis of thei...

816 citations

01 Jan 2016
TL;DR: This book helps people to enjoy a good book with a cup of coffee in the afternoon, instead they juggled with some malicious bugs inside their laptop.
Abstract: Thank you for downloading magnetic resonance imaging physical principles and sequence design. As you may know, people have look numerous times for their chosen books like this magnetic resonance imaging physical principles and sequence design, but end up in harmful downloads. Rather than enjoying a good book with a cup of coffee in the afternoon, instead they juggled with some malicious bugs inside their laptop.

695 citations

Journal ArticleDOI
TL;DR: This review integrates the key molecular and cellular mechanisms of resolution and describes how abrogation of chemokine signalling blocks continued neutrophil tissue infiltration and how apoptotic neutrophils attract monocytes and macrophages to induce their clearance.
Abstract: Resolution of inflammation is a coordinated and active process aimed at restoration of tissue integrity and function. This review integrates the key molecular and cellular mechanisms of resolution. We describe how abrogation of chemokine signalling blocks continued neutrophil tissue infiltration and how apoptotic neutrophils attract monocytes and macrophages to induce their clearance. Uptake of apoptotic neutrophils by macrophages reprograms macrophages towards a resolving phenotype, a key event to restore tissue homeostasis. Finally, we highlight the therapeutic potential that derives from understanding the mechanisms of resolution.

590 citations

Journal ArticleDOI
TL;DR: Noninvasive imaging can be employed to visualize and quantify how efficient passive or active drug targeting is in individual patients and, on this basis, to preselect patients likely to respond to nanomedicine-based chemotherapeutic interventions.
Abstract: Noninvasive imaging is used for many different (pre)clinical purposes, ranging from disease diagnosis, disease staging, and treatment monitoring to the visualization and quantification of nanomedicine-mediated drug targeting and (triggered) drug release. Noninvasive imaging can be employed to visualize and quantify how efficient passive or active drug targeting is in individual patients and, on this basis, to preselect patients likely to respond to nanomedicine-based chemotherapeutic interventions. In addition, it can be used to visualize the off-target localization of nanomedicines, e.g., in potentially endangered healthy tissues, which under certain circumstances might lead to exclusion from targeted treatment. Moreover, by systematically integrating imaging also during follow-up and by closely monitoring therapeutic responses upon nanomedicine treatment, clinical decision making can be facilitated and improved, as decisions on whether or not to (dis)continue treatment and on whether or not to adjust drug doses can be made relatively early on. Noninvasive imaging may be particularly useful in the case of metastatic disease. By subsequently performing PET or SPECT scans with radionuclide-labeled nanomedicines, information can be obtained on the accumulation of these formulations in both primary tumors and metastases, and treatment protocols can be adapted accordingly.

372 citations

Journal ArticleDOI
TL;DR: This review summarizes the historical development and effects of particular phospholipids and surfactants on the biophysical properties and in vivo efficacy of thermosensitive liposome formulations and treatment strategies for solid tumors are discussed.
Abstract: Thermosensitive liposomes are a promising tool for external targeting of drugs to solid tumors when used in combination with local hyperthermia or high intensity focused ultrasound. In vivo results have demonstrated strong evidence that external targeting is superior over passive targeting achieved by highly stable long-circulating drug formulations like PEGylated liposomal doxorubicin. Up to March 2014, the Web of Science listed 371 original papers in this field, with 45 in 2013 alone. Several formulations have been developed since 1978, with lysolipid-containing, low temperature-sensitive liposomes currently under clinical investigation. This review summarizes the historical development and effects of particular phospholipids and surfactants on the biophysical properties and in vivo efficacy of thermosensitive liposome formulations. Further, treatment strategies for solid tumors are discussed. Here we focus on temperature-triggered intravascular and interstitial drug release. Drug delivery guided by magnetic resonance imaging further adds the possibility of performing online monitoring of a heating focus to calculate locally released drug concentrations and to externally control drug release by steering the heating volume and power. The combination of external targeting with thermosensitive liposomes and magnetic resonance-guided drug delivery will be the unique characteristic of this nanotechnology approach in medicine.

289 citations