Dauer epileptischer Anfälle während selektiver pharyngealer Hirnkühlung / Duration of induced seizures during selective pharyngeal brain cooling

Trübel, H.; Hermán, Péter; Kampmann, C; Novotny, EJ; Hyder, Fahmeed

doi:10.1515/bmt.2004.052

Cited by 4 publications

(2 citation statements)

References 18 publications

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“…However, lack of thalamic blood flow increase with thalamic hyperthermia suggests that this region may be more susceptible to injury during MDMA exposure. While whole-body cooling may be effective for cooling the whole brain, the use of pharyngeal cooling may selectively cool deeper parts of the brain more efficiently (28)(29)(30)(31)(32). It is clear that a better description of the mechanisms involved in the MDMAinduced brain hyperthermia is required to separate measurements of intracerebral metabolic heat production, which cannot be achieved directly from temperature measurements due to heat removal/addition by blood flow or conductive and dissipative heat loss to adjacent regions.…”

Section: Discussionmentioning

confidence: 99%

Distribution of temperature changes and neurovascular coupling in rat brain following 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”) exposure

et al. 2015

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(+/−)3,4-methylenedioxymethamphetamine (MDMA, ‘ecstasy’) is an abused psychostimulant producing strong monoaminergic stimulation and whole-body hyperthermia. MDMA-induced thermogenesis involves activation of uncoupling proteins (UCP), primarily a type specific to skeletal muscle (UCP-3) and which is absent in brain, although other UCP types are expressed in brain (e.g., thalamus) and might contribute to thermogenesis. Since neuroimaging of brain temperature could provide insights of MDMA action, we measured spatial distributions of systemically-administered MDMA-induced temperature changes and dynamics in rat cortex and subcortex using a novel magnetic resonance method, Biosensor Imaging of Redundant Deviation of Shifts (BIRDS), with an exogenous temperature-sensitive probe (thulium ion and macrocyclic chelate 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethyl-1,4,7,10-tetraacetate (DOTMA4−)). The MDMA-induced temperature rise in cortex was greater than in subcortex (1.6±0.4°C vs. 1.3±0.4°C) and occurred more rapidly (2.0±0.2°C/h vs. 1.5±0.2°C/h). MDMA-induced temperature changes and dynamics in cortex and body were correlated, although body temperature exceeded cortex before and after MDMA. Temperature, neuronal activity, and blood flow (CBF) were measured simultaneously in cortex and subcortex (i.e., thalamus) to investigate possible differences of MDMA-induced warming across brain regions. MDMA-induced warming correlated with increases in neuronal activity and blood flow in cortex, suggesting that the normal neurovascular response to increased neural activity was maintained. In contrast to cortex, a biphasic relationship was seen in subcortex (i.e., thalamus), with a decline in CBF as temperature and neural activity rose, transitioning to a rise in CBF for temperature >37°C, suggesting that MDMA affected CBF and neurovascular coupling differently in subcortical regions. Considering that MDMA effects on CBF and heat dissipation (as well as potential heat generation) may vary regionally, neuroprotection may require different cooling strategies.

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Section: Discussionmentioning

confidence: 99%

Distribution of temperature changes and neurovascular coupling in rat brain following 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”) exposure

et al. 2015

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“…These results suggest that EuDOTA-(gly) À 4 and other PARACEST-like agents, which possess large numbers of exchangeable and nonexchangeable protons, can be used as a dual biosensor featuring both CEST and BIRDS properties. Future studies should seek agent designs that enhance BIRDS sensitivity without diminishing the advantages of CEST, as these combined properties in a single molecular probe could have a wide range of MRI and MRS applications in functional brain studies (34)(35)(36)(37)(38).…”

Section: Discussionmentioning

confidence: 99%

A lanthanide complex with dual biosensing properties: CEST (chemical exchange saturation transfer) and BIRDS (biosensor imaging of redundant deviation in shifts) with europium DOTA–tetraglycinate

et al. 2011

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Responsive contrast agents (RCAs) [R1.12] composed of lanthanide III ion (Ln3+) complexes with a variety of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (DOTA4−) derivatives have shown great potential as molecular imaging agents for magnetic resonance (MR). A variety of LnDOTA-tetraamide complexes have been demonstrated as RCAs for molecular imaging with chemical exchange saturation transfer (CEST). The CEST method detects proton exchange between bulk water and any exchangeable sites on the ligand itself or an inner sphere of bound water that is shifted by a paramagnetic Ln3+ bound in the core of the macrocycle. It has also been shown that molecular imaging is possible when the RCA itself is observed (i.e., not its affect on bulk water) using a method called biosensor imaging of redundant deviation in shifts (BIRDS). The BIRDS method utilizes redundant information stored in the non-exchangeable proton resonances emanating from the paramagnetic RCA for ambient factors like temperature and/or pH. Thus CEST and BIRDS rely on exchangeable and non-exchangeable protons, respectively, for biosensing. We posited that it is feasible to combine these two biosensing features into the same RCA (i.e., dual CEST and BIRDS properties). A complex between europium ion (Eu3+) and DOTA-tetra-glycinate (DOTA-(gly)44−) is used to demonstrate that its CEST characteristics are preserved while BIRDS properties are detected. In vitro temperature sensitivity of EuDOTA-(gly)4− is used to show that qualitative MR contrast with CEST can be calibrated using quantitative MR mapping with BIRDS, thereby enabling quantitative molecular imaging at high spatial resolution.

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In vivo three‐dimensional molecular imaging with Biosensor Imaging of Redundant Deviation in Shifts (BIRDS) at high spatiotemporal resolution

et al. 2013

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Spectroscopic signals which emanate from complexes between paramagnetic lanthanide III ions (e.g., Tm3+) and macrocyclic chelates (e.g., 1,4,7,10-tetramethyl 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate, or DOTMA4−) are sensitive to physiology (e.g., temperature and/or pH). Because non-exchanging protons from these lanthanide-based macrocyclic agents have relaxation times on the order of a few milliseconds, rapid data acquisition is possible with chemical shift imaging (CSI). Thus Biosensor Imaging of Redundant Deviation in Shifts (BIRDS) which originate from non-exchanging protons of these paramagnetic agents, but exclude water proton detection, can allow molecular imaging. Previous 2D CSI experiments with such lanthanide-based macrocyclics allowed acquisition from ~12 µL voxels in rat brain within 5 minutes using rectangular encoding of k-space. Because cubical encoding of k-space in 3D for whole brain coverage increases CSI acquisition time to several tens of minutes or more, a faster CSI technique is required for BIRDS to be of practical use. Here we demonstrate a CSI acquisition method to improve 3D molecular imaging capabilities with lanthanide-based macrocyclics. Using TmDOTMA−, we show datasets from a 20×20×20 mm3 field-of-view with voxels of ~1 µL effective volume acquired within 5 minutes (at 11.7T) for temperature mapping. By employing reduced spherical encoding with Gaussian weighting (RESEGAW) instead of cubical encoding of k-space, a significant increase in CSI signal is obtained. In vitro and in vivo 3D CSI data with TmDOTMA−, and presumably similar lanthanide-based macrocyclics, suggest that acquisition using RESEGAW can be used for high spatiotemporal molecular mapping with BIRDS.

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Dauer epileptischer Anfälle während selektiver pharyngealer Hirnkühlung / Duration of induced seizures during selective pharyngeal brain cooling

Cited by 4 publications

References 18 publications

Distribution of temperature changes and neurovascular coupling in rat brain following 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”) exposure

Distribution of temperature changes and neurovascular coupling in rat brain following 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”) exposure

A lanthanide complex with dual biosensing properties: CEST (chemical exchange saturation transfer) and BIRDS (biosensor imaging of redundant deviation in shifts) with europium DOTA–tetraglycinate

In vivo three‐dimensional molecular imaging with Biosensor Imaging of Redundant Deviation in Shifts (BIRDS) at high spatiotemporal resolution

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