| 1. |
- Enblad P., Frykholm P., Valtysson J., Silander H C., Andersson J., Fasth K J., Watanabe Y., Långström B., Hillered L., Persson L.
(author)
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Middle cerebral artery occlusion and reperfusion in primates monitored by microdialysis and sequential positron emission tomography
- 2001
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In: Stroke. ; :32 (7), s. 1574-80
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Journal article (peer-reviewed)
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| 2. |
- Gedeborg, Rolf, et al.
(author)
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Adverse effects of high-dose epinephrine on cerebral blood flow during experimental cardiopulmonary resuscitation
- 2000
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In: Critical Care Medicine. - 0090-3493 .- 1530-0293. ; 28:5, s. 1423-1430
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Journal article (peer-reviewed)abstract
- OBJECTIVE:To study the effects of high-dose epinephrine, compared with standard-dose epinephrine, on the dynamics of superficial cortical cerebral blood flow as well as global cerebral oxygenation during experimental cardiopulmonary resuscitation. We hypothesized that high-dose epinephrine might be unable to improve cerebral blood flow during cardiopulmonary resuscitation as compared with standard-dose epinephrine.DESIGN:Randomized controlled study.SETTING:University hospital research laboratory.SUBJECTS:A total of 20 male anesthetized piglets.INTERVENTIONS:Ventricular fibrillation was induced. A nonintervention interval of 8 mins was followed by open-chest cardiopulmonary resuscitation. The animals were randomized to receive repeated bolus injections of either 20 microg/kg (standard-dose group, n = 10) or 200 microg/kg (high-dose group, n = 10) of epinephrine.MEASUREMENTS AND MAIN RESULTS:Focal cortical cerebral blood flow was measured continuously by using laser Doppler flowmetry. The duration of blood flow increase was significantly shorter in the high-dose group after the second dose of epinephrine. In the high-dose group there was also a consistent tendency for lower peak levels and shorter duration of flow increase in response to repeated bolus doses of epinephrine. Cerebral oxygen extraction ratio was significantly lower in the high-dose group after administration of epinephrine.CONCLUSIONS:Repeated bolus doses of epinephrine 200 microg/kg, as compared with 20 microg/kg, do not improve superficial cortical cerebral blood flow during experimental open-chest cardiopulmonary resuscitation. High-dose epinephrine appears to induce vasoconstriction of cortical cerebral blood vessels resulting in redistribution of blood flow from superficial cortex. This might be one explanation for the failure of high-dose epinephrine to improve overall outcome in clinical trials.
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| 3. |
- Gedeborg, Rolf, et al.
(author)
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Cerebral ischaemia in experimental cardiopulmonary resuscitation--comparison of epinephrine and aortic occlusion.
- 2001
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In: Resuscitation. - 0300-9572 .- 1873-1570. ; 50:3, s. 319-29
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Journal article (peer-reviewed)abstract
- The apparent inability of epinephrine to improve outcome after cardiopulmonary resuscitation (CPR) could be caused by direct negative effects on the cerebral circulation. Constant aortic occlusion with a balloon catheter could be an alternative way to improve coronary and cerebral perfusion during CPR. The objective of the present study was to compare the effects of standard-dose epinephrine with balloon occlusion of the descending aorta on cortical cerebral blood flow augmentation during CPR. Ventricular fibrillation was induced in 24 anaesthetised piglets. A non-intervention interval of 9 min was followed by open-chest CPR. The animals were randomised to receive repeated intravenous bolus doses of epinephrine 20 microg/kg or balloon occlusion of the descending aorta. Focal cortical cerebral blood flow was measured continuously using laser-Doppler flowmetry. Balloon occlusion of the aorta resulted in a significantly higher mean cortical cerebral blood flow and a lower cerebral oxygen extraction ratio than epinephrine during CPR. After restoration of spontaneous circulation the cerebral perfusion appeared compromised to the same extent in both groups, with lower blood flow compared to baseline, high cerebral oxygen extraction and cerebral tissue acidosis. No difference in cerebral cortical vascular resistance between the two groups could be detected. It is concluded that aortic balloon occlusion was superior to epinephrine in cerebral blood flow augmentation during resuscitation and did not generate adverse effects on cerebral blood flow, oxygenation or tissue pH after restoration of spontaneous circulation. No evidence of cerebral vasoconstriction induced by standard-dose epinephrine was found.
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| 4. |
- Melberg, Atle, et al.
(author)
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Monozygotic twins with MELAS-like syndrome lacking ragged red fibers and lactacidaemia
- 1996
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In: Acta Neurologica Scandinavica. - : Hindawi Limited. - 0001-6314 .- 1600-0404. ; 94:4, s. 233-41
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Journal article (peer-reviewed)abstract
- Typical cases of MELAS present a combination of clinical and neuroradiological features, lactacidaemia, and ragged red fibers (RRFs) in striated muscle. We have observed a MELAS-like syndrome in monozygotic twins. They developed seizures typically in conjunction with physical exertion, sleep deprivation or febrile episodes. Stroke-like episodes occurred usually during seizures. In twin 2 the course was fatal at age 20 years. Neuroradiological findings were typical of MELAS. Plasma lactate was normal in both. CSF lactate was normal in twin 1 and normal/elevated in twin 2. RRFs were not seen in muscle biopsies of the twins. Complex I activity was reduced in muscle in twin 1. Brain tissue removed at epilepsy surgery in twin 2 showed the presence of mitochondrial angiopathy. The commonest mitochondrial DNA mutation in MELAS, at base pair 3243, was absent. Lactacidaemia and mitochondrial myopathy with RRFs constitute part of the diagnostic criteria of MELAS. However, the absence of these features does not exclude mitochondrial disorder with the serious manifestations of MELAS (seizures and stroke-like episodes) as seen in these twins.
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| 5. |
- Weis, J, et al.
(author)
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Magnetic resonance spectroscopic imaging for visualization and correction of distortions in MRI : high precision applications in neurosurgery.
- 1998
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In: Magnetic Resonance Imaging. - 0730-725X .- 1873-5894. ; 16:10, s. 1265-72
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Journal article (peer-reviewed)abstract
- We present a method for the quantification and correction of geometrical/intensity distortions of magnetic resonance images predominantly caused by bulk magnetic susceptibility shifts due to susceptibility heterogeneities of measured biologic tissues and shape of the object under investigation. The method includes precise and fast measurements of the static magnetic-field distribution inside the measured object and automated data processing. Magnetic-field deviations in the range (-2.4; 2.6) ppm were found in the human brain at B0 = 1.5 T. For routinely used imaging parameters, with a read gradient strength of about approximately 1 mT/m, the magnetic-field perturbations in the human brain can cause geometrical distortions up to +/-4 mm and intensity changes up to +/-50%. MR images corrected by the described method are suitable for planning high precision applications in neurosurgery.
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