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- Deshpande, J, et al.
(författare)
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Ultrastructural changes in the hippocampal CA1 region following transient cerebral ischemia: evidence against programmed cell death.
- 1992
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Ingår i: Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale. - 0014-4819. ; 88:1, s. 91-105
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Tidskriftsartikel (refereegranskat)abstract
- The ultrastructural changes in the pyramidal neurons of the CA1 region of the hippocampus were studied 6 h, 24 h, 48 h, and 72 h following a transient 10 min period of cerebral ischemia induced by common carotid occlusion combined with hypotension. The pyramidal neurons showed delayed neuronal death (DND), i.e. at 24 h and 48 h postischemia few structural alterations were noted in the light microscope, while at 72 h extensive neuronal degeneration was apparent. The most prominent early ultrastructural changes were polysome disaggregation, and the appearance of electron-dense fluffy dark material associated with tubular saccules. Mitochondria and nuclear elements appeared intact until frank neuronal degeneration. The dark material accumulated with extended periods of recirculation in soma and in the main trunks of proximal dendrites, often beneath the plasma membrane, less frequently in the distal dendrites and seldom in spines. Protein synthesis inhibitors (anisomycin, cycloheximide) and an RNA synthesis inhibitor (actinomycin D), administered by intrahippocampal injections or subcutaneously, did not mitigate neuronal damage. Therefore, DND is probably not apoptosis or a form of programmed cell death. We propose that the dark material accumulating in the postischemic period represents protein complexes, possibly aggregates of proteins or internalized plasma membrane fragments, which may disrupt vital cellular structure and functions, leading to cell death.
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| 4. |
- Lindén, Thomas, 1962, et al.
(författare)
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Protective effect of lesion to the glutamatergic cortico-striatal projections on the hypoglycemic nerve cell injury in rat striatum.
- 1987
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Ingår i: Acta neuropathologica. - 0001-6322. ; 74:4, s. 335-44
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Tidskriftsartikel (refereegranskat)abstract
- In rat striatum severe hypoglycemia causes an irreversible nerve cell injury, which does not become manifest until during the post-insult recovery period. This injury can be ameliorated by lesions of the glutamatergic cortico-striatal pathway, which suggests that an "excitotoxic" effect mediated by the glutamatergic input is the likely cause of the post-hypoglycemic nerve cell destruction. In this paper we further characterize the protective effect of abolishing the glutamatergic innervation to striatum at the ultrastructural level. Two weeks after a unilateral cortical ablation rats were subjected to 30 min of severe hypoglycemia with isoelectric EEG and killed either immediately after the insult or following 60 min of recovery induced by restoring the blood glucose levels. Immediately after the hypoglycemic insult the structure of striatum was similar on both sides (except for the changes attributable to the ablation); i.e., the neurons and their dendrites had pale cytoplasm with condensed mitochondria, sparse RER and pinpoint ribosomes. After 60 min restitution numerous striatal neurons on the non-protected, non-ablated side had turned variably dark and condensed, whereas underneath the ablation they remained similar as immediately after hypoglycemia. This sequence indicates that the most likely cause of nerve cell destruction on the non-protected side is the "excitotoxic" effect mediated by the glutamatergic innervation, which is superimposed on the action of the hypoglycemic insult per se. Furthermore, the primary condensation of neurons and their dendrites indicate existence of another type of acute "excitotoxic" nerve cell injury which differs from the previously described injury characterized by neuronal swelling.
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| 5. |
- Lindén, Thomas, 1962, et al.
(författare)
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Risk of central pontine myelinolysis in the treatment of severe hyponatremia
- 1989
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Ingår i: Läkartidningen. - 0023-7205. ; 86:20, s. 1905-7
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Tidskriftsartikel (refereegranskat)abstract
- Central pontine myelinolysis is a life-threatening condition involving the demyelination of axons in certain areas of the brain. It has been shown almost invariably to occur in connection with hospital care. In recent years, a connection has been noted between the rapid restitution of low serum sodium and the development of the condition. In this review, the most recent scientific information is summarized. It is concluded that the risk should always be considered in treating a hyponatremic patient. The serum sodium level should be raised slowly and the acute treatment ended before normal serum sodium levels are reached, ie when the patient is still slightly hyponatremic.
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