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- Kåhrström, J, et al.
(författare)
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Neonatal pre-ganglionic sympathectomy affects morphometrically defined architecture in rat cerebral arteries
- 1996
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Ingår i: Acta Physiologica Scandinavica. - 0001-6772. ; 157:2, s. 225-231
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Tidskriftsartikel (refereegranskat)abstract
- In order to clarify further the nature of the long-term influence on the cerebral vasculature by the sympathetic nerves, a bilateral cervical pre-ganglionic denervation was performed in 1-week-old rats. Four weeks later, morphometric determinations of the vascular dimensions revealed diminished media cross-sectional areas and luminal radii in the middle cerebral and posterior cerebral arteries, whereas these parameters were unaffected in the basilar artery. In the latter artery, however, a 40% increase in the cross-sectional area of the internal elastic membrane was found. No re-innervation of the denervated ganglia occurred during the course of the experiment. The results suggest that the long-term effect exerted by the sympathetic nerves is associated with the nerve activity, rather than being a true trophic influence.
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- Nordborg, C, et al.
(författare)
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Secondary thalamic lesions after ligation of the middle cerebral artery: an ultrastructural study
- 1995
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Ingår i: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 1432-0533 .- 0001-6322. ; 91:1, s. 61-66
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Tidskriftsartikel (refereegranskat)abstract
- Earlier light microscopic, immunocytochemical and morphometric investigations indicate that noxious substances transported with the vasogenic edema from hemispheric infarcts influence the character, timing and extent of the secondary thalamic lesions. The object of the present study was to analyze the ultrastructure of the secondary damage and the cytolytic nerve cell change which ensues in the thalamus within a week after the infarction. Adult spontaneously hypertensive rats (SHR) were studied either 7 days after permanent ligation of the right middle cerebral artery (MCA) (n = 4) or 7 days after a 2-h temporary occlusion of the MCA (n = 4). Light microscopy revealed damage in the ipsilateral thalamic nuclei and the electron microscopic analysis showed that the cytolytic nerve cell degeneration was somatodendritic. Central chromatolysis was not observed. Somatodendritic nerve cell degeneration, as found in the secondary thalamic lesions in the present study, has been described in excitotoxic brain damage as well as in chronic, edematous lesions in stroke-prone spontaneously hypertensive rats. The possibility that the cytolytic thalamic nerve cell lesion is influenced by excitatory, noxious substances spreading with the edema fluid from the infarct has, thus, to be considered.
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- Olmarker, K, et al.
(författare)
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Chondroitinase ABC (pharmaceutical grade) for chemonucleolysis. Functional and structural evaluation after local application on intraspinal nerve structures and blood vessels.
- 1996
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Ingår i: Spine. - : Ovid Technologies (Wolters Kluwer Health). - 0362-2436. ; 21:17, s. 1952-6
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Tidskriftsartikel (refereegranskat)abstract
- The effects on nerve tissue and blood vessels of locally applied chondroitinase ABC were studied in two experimental models using chymopapain and the vehicle of chondroitinase ABC for controls.To assess the effects of chondroitinase ABC on blood vessels and nerve tissue after local application.Chondroitinase ABC has been suggested for chemonucleolysis because it has a high specificity for nucleus pulposus matrix, which could mean a high efficiency in dissolving disc tissue combined with a low risk of side effects on other tissues.Chondroitinase ABC or controls were injected intrathecally in the pig, and nerve conduction velocity and histologic changes were assessed after 7 days. The same substances were injected into the hamster cheek pouch and studied for 60 minutes for microvascular effects. The vehicle for the enzyme was used as a negative control and chymopapain in a therapeutic concentration served as a positive control.In all series there was a slight intrathecal fibrotic reaction that was most pronounced after chymopapain injection. The effects on nerve conduction velocity and nerve morphology were similar between chondroitinase ABC and its vehicle. Chymopapain induced a significant reduction in nerve conduction velocity and pronounced histologic changes. In the cheek pouch, chymopapain induced a stand-still of blood flow at the injection site, and microhemorrhage and macromolecular leakage from the vessels at the border of the injection site. Only a slightly reduced blood flow was occasionally found after injection of chondroitinase ABC and controls.In agreement with the current literature, these observations indicate that chondroitinase ABC is safe regarding adverse effects on nerve tissue and blood vessels. The slight reduction in conduction velocity after intrathecal injection of chondroitinase ABC or its vehicle is most likely the result of surgical injury while releasing the nerve roots from the intrathecal fibrous adhesions. Such adhesions may be related to the laminectomy per se, and probably have no pathophysiologic significance.
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- Risedal, Anette, et al.
(författare)
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Infarct volume and functional outcome after pre- and postoperative administration of metyrapone, a steroid synthesis inhibitor, in focal brain ischemia in the rat
- 1999
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Ingår i: European Journal of Neurology. - : Wiley. - 1351-5101 .- 1468-1331. ; 6:4, s. 481-486
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Tidskriftsartikel (refereegranskat)abstract
- High blood levels of glucocorticoids are associated with increased mortality, confusion and poor functional outcome in stroke patients. It has been proposed that inhibition of glucocorticoids in acute stroke might be beneficial, but experimental data are conflicting and no long-term follow-up study has been reported. We have studied whether pre- or postoperative administration of metyrapone, a steroid synthesis inhibitor, can influence long-term outcome after ligation of the right middle cerebral artery (MCA) distal to the striatal branches in hypertensive rats. Metyrapone (200 mg/kg) was administered either 30 min before or 1, 12 and 24 h after MCA occlusion. Limb placements and ability to traverse a rotating pole were evaluated pre- and postoperatively. Infarct size, histology and GFAP immunoreactivity were evaluated on 5 microm coronal sections from brains perfused in situ 4 weeks after the ischemic event. Pretreatment did not influence outcome, whereas postoperative administration of metyrapone significantly increased infarct volume (P < 0.05). Post-treated rats performed significantly worse than vehicle-treated rats on the rotating pole 3 weeks after the operation (P < 0.05). Our results do not support the hypothesis that inhibition of glucocorticoid synthesis improves outcome after cerebral ischemia.
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- Zeng, J, et al.
(författare)
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Are neuronal markers and neocortical graft-host interface influenced by housing conditions in rats with cortical infarct cavity?
- 1999
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Ingår i: Brain Research Bulletin. - 0361-9230. ; 48:2, s. 165-171
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to study if exposure to an enriched environment influenced graft-host interface and neuronal markers in neocortical grafts implanted in cortical infarct cavities 3 weeks after distal ligation of the middle cerebral artery in adult hypertensive rats. Half the rats were exposed to an enriched environment for 2 h daily 5 days a week starting 1 week after the arterial ligation. The brain was fixed by perfusion 4 weeks postgrafting. The immunoreactivity to glial fibrillary acidic protein, microtubule associated protein 2, and synaptophysin was studied in coronal paraffin-embedded sections. A distinct glial border separated the infarct cavity from the surrounding brain in sham-transplanted rats. Most grafts filled the larger part of the infarct cavity. In 8 of 18 transplants, 4 in each experimental group, part of the transplants protruded through the thin glial membrane that delineated the transplant-host interface into the adjacent host brain tissue. Microtubule associated protein 2 immunostained sections indicated bridging of dendrites in the host-transplant interface. Synaptophysin immunoreactivity was significantly higher in grafts than in contralateral cortex. However, graft morphology and neuronal marker immunoreactivity did not differ between rats housed in standard and activity stimulating cages.
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