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- Sandvig, Axel, et al.
(författare)
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Axonal tracing of the normal and regenerating visual pathway of mouse, rat, frog, and fish using manganese-enhanced MRI (MEMRI)
- 2011
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Ingår i: Journal of Magnetic Resonance Imaging. - Chicago, IL : Society for Magnetic Resonance Imaging. - 1053-1807 .- 1522-2586. ; 34:3, s. 670-675
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To assess optic nerve (ON) regeneration after injury by applying manganese-enhanced MRI (MEMRI) in a study of comparative physiology between nonregenerating rat and mouse species and regenerating frog and fish species.Materials and Methods: The normal visual projections of rats, mice, frogs, and fish was visualized by intravitreal MnCl(2) injection followed by MRI. Rats and mice with ON crush (ONC) were divided into nonregenerating (ONC only), and regenerating animals with peripheral nerve graft (ONC+PNG; rats) or lens injury (ONC+LI; mice) and monitored by MEMRI at 1 and 20 days post-lesion (dpl). Frog and fish with ON transection (ONT) were monitored by MEMRI up to 6 months postlesion (mpl).Results: Signal intensity profiles of the Mn(2+)-enhanced ON were consistent with ON regeneration in the ONC+PNG and ONC+LI rat and mice groups, respectively, compared with the nonregenerating ONC groups. Furthermore, signal intensity profiles of the Mn(2+)-enhanced ON obtained between 1 mpl and 6 mpl in the fish and frog groups, respectively, were consistent with spontaneous, complete ON regeneration.Conclusion: Taken together, these results demonstrate that MEMRI is a viable method for serial, in vivo monitoring of normal, induced, and spontaneously regenerating optic nerve axons in different species.
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| 2. |
- Sandvig, Ioanna, et al.
(författare)
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In vivo MRI of olfactory ensheathing cell grafts and regenerating axons in transplant mediated repair of the adult rat optic nerve
- 2012
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Ingår i: NMR in Biomedicine. - Malden, MA, USA : John Wiley & Sons. - 0952-3480 .- 1099-1492. ; 25:4, s. 620-631
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the present study was to use magnetic resonance imaging (MRI) as a tool for monitoring transplant-mediated repair of the adult rat visual pathway. We labelled rat olfactory ensheathing cells (OECs) using micron-sized particles of iron oxide (MPIO) and transplanted them by: i) intravitreal injection (ivit) and ii) intra-optic nerve (ON) injection (iON) in adult rats with ON crush (ONC) injury. We applied T2-weighted MRI and manganese-enhanced MRI (MEMRI) to visualise transplanted cells and ON axons at specific times after injury and cell engraftment. Our findings demonstrate that ivit MPIO-labelled OECs are unequivocally detected by T2-weighted MRI in vivo and that the T1-weighted 3D FLASH sequence applied for MEMRI facilitates simultaneous visualisation of Mn2+-enhanced regenerating retinal ganglion cell (RGC) axons and MPIO-labelled OEC grafts. Furthermore, analysis of MRI data and ultrastructural findings supports the hypothesis that iON OEC transplants mediate regeneration and remyelination of RGC axons post injury.
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| 3. |
- Sandvig, Ioanna, et al.
(författare)
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Labelling of olfactory ensheathing cells with micron-sized particles of iron oxide and detection by MRI
- 2012
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Ingår i: Contrast Media & Molecular Imaging. - Hoboken, NJ : Wiley-Blackwell. - 1555-4309 .- 1555-4317. ; 7:4, s. 403-410
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Tidskriftsartikel (refereegranskat)abstract
- A crucial issue in transplant-mediated repair of the damaged central nervous system (CNS) is serial non-invasive imaging of the transplanted cells, which has led to interest in the application of magnetic resonance imaging (MRI) combined with designated intracellular magnetic labels for cell tracking. Micron-sized particles of iron oxide (MPIO) have been successfully used to track cells by MRI, yet there is relatively little known about either their suitability for efficient labelling of specific cell types, or their effects on cell viability. The purpose of this study was to develop a suitable MPIO labelling protocol for olfactory ensheathing cells (OECs), a type of glia used to promote the regeneration of CNS axons after transplantation into the injured CNS. Here, we demonstrate an OEC labelling efficiency of >90% with an MPIO incubation time as short as 6?h, enabling intracellular particle uptake for single-cell detection by MRI without affecting cell proliferation, migration and viability. Moreover, MPIO are resolvable in OECs transplanted into the vitreous body of adult rat eyes, providing the first detailed protocol for efficient and safe MPIO labelling of OECs for non-invasive MRI tracking of transplanted OECs in real time for use in studies of CNS repair and axon regeneration. Copyright (c) 2012 John Wiley & Sons, Ltd.
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