Houston, TX, United States
Houston, TX, United States

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Partovi S.,University of Basel | Partovi S.,key Heart and Vascular Center | Schulte A.-C.,University of Basel | Jacobi B.,University of Basel | And 10 more authors.
Journal of Magnetic Resonance Imaging | Year: 2012

Purpose: To evaluate the dependence of skeletal muscle blood oxygenation level-dependent (BOLD) effect and time course characteristics on magnetic field strength in healthy volunteers using an ischemia/reactive hyperemia paradigm. Materials and Methods: Two consecutive skeletal muscle BOLD magnetic resonance imaging (MRI) measurements in eight healthy volunteers were performed on 1.5 T and 3.0 T whole-body MRI scanners. For both measurements a fat-saturated multi-shot multiecho gradient-echo EPI sequence was applied. Temporary vascular occlusion was induced by suprasystolic cuff compression of the thigh. T2*time courses were obtained from two different calf muscles and characterized by typical curve parameters. Ischemia- and hyperemia-induced changes in R2*(ΔR2*) were calculated for both muscles in each volunteer at the two field strengths. Results: Skeletal muscle BOLD changes are dependent on magnetic field strength as the ratio ΔR2*(3.0 T)/ ΔR2*(1.5 T) was found to range between 1.6 and 2.2. Regarding time course characteristics, significantly higher relative T2*changes were found in both muscles at 3.0 T. Conclusion: The present study shows an approximately linear field strength dependence of ΔR2*in the skeletal muscle in response to ischemia and reactive hyperemia. Using higher magnetic fields is advisable for future BOLD imaging studies of peripheral limb pathologies. © 2012 Wiley Periodicals, Inc.


La Francesca S.,key Heart and Vascular Center | Ting A.E.,Athersys, Inc. | Sakamoto J.,Houston Methodist Research Institute | Rhudy J.,Houston Methodist Research Institute | And 8 more authors.
Transplantation Research | Year: 2014

Background: Primary graft dysfunction (PGD) is a significant cause of early morbidity and mortality following lung transplantation. Improved organ preservation techniques will decrease ischemia-reperfusion injury (IRI) contributing to PGD. Adult bone marrow-derived adherent stem cells, including mesenchymal stromal (stem) cells (MSCs) and multipotent adult progenitor cells (MAPCs), have potent anti-inflammatory actions, and we thus postulated that intratracheal MAPC administration during donor lung processing would decrease IRI. The goal of the study was therefore to determine if intratracheal MAPC instillation would decrease lung injury and inflammation in an ex vivo human lung explant model of prolonged cold storage and subsequent reperfusion. Methods: Four donor lungs not utilized for transplant underwent 8 h of cold storage (4°C). Following rewarming for approximately 30 min, non-HLA-matched allogeneic MAPCs (1 × 107 MAPCs/lung) were bronchoscopically instilled into the left lower lobe (LLL) and vehicle comparably instilled into the right lower lobe (RLL). The lungs were then perfused and mechanically ventilated for 4 h and subsequently assessed for histologic injury and for inflammatory markers in bronchoalveolar lavage fluid (BALF) and lung tissue. Results: All LLLs consistently demonstrated a significant decrease in histologic and BALF inflammation compared to vehicle-treated RLLs. Conclusions: These initial pilot studies suggest that use of non-HLA-matched allogeneic MAPCs during donor lung processing can decrease markers of cold ischemia-induced lung injury.

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