| 1. |
- Belichenko, P, et al.
(författare)
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Dendritic morphology in epileptogenic cortex from TRPE patients, revealed by intracellular Lucifer Yellow microinjection and confocal laser scanning microscopy.
- 1994
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Ingår i: Epilepsy research. - 0920-1211. ; 18:3, s. 233-47
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Tidskriftsartikel (refereegranskat)abstract
- Biopsy material was obtained from cortical epileptogenic zones (eight temporal, one occipital, one parietal and one frontal) of eleven patients aged 1.5-47 years with therapy-resistant partial epilepsy (TRPE) undergoing epilepsy surgery. Control autopsy material (two temporal, two occipital, one parietal and one frontal) was removed from six neurologically healthy cases within 6-10 hours postmortem delay. In each specimen, 100-300 pyramidal and non-pyramidal neurons were visualized by intracellular Lucifer Yellow microinjection. Single neurons were imaged using CLSM generated serial optical sections; 2-D reconstruction of each neuron was made using z-projection of serial optical images, and 3-D reconstructions and rotations were computerized. Neuronal maps from TRPE biopsies, compared to control autopsies, show markedly increased numbers of dendritic abnormalities of single pyramidal and non-pyramidal neurons in layers I, II-III, V-VII, and in the subcortical white matter. The abnormalities include: (1) increased number of non-pyramidal cells in layer I; (2) many pyramidal cells with two or three dendrites originating apically, rather than one single apical dendrite, in layers II-III; (3) atypical orientation of oblique apical and basal dendrites in pyramidal neurons of layers II-VII; (4) increased number of atypical 'dinosaur-like' and fusiform cells in layers V-VII; (5) numerous neurons in the white matter. These abnormalities may be etiological in cases with early onset, and predisposing in cases with late onset.
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| 2. |
- Grabowski, Martin, et al.
(författare)
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Brain capillary density and cerebral blood flow after occlusion of the middle cerebral artery in normotensive Wistar-Kyoto rats and spontaneously hypertensive rats
- 1993
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Ingår i: Journal of Hypertension. - 1473-5598. ; 11:12, s. 1363-1368
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: In order to elucidate why spontaneously hypertensive rats (SHR) develop larger brain infarcts distal to an arterial occlusion than normotensive Wistar-Kyoto (WKY) rats, we determined the surface and volume densities of cerebral capillaries, and the regional cerebral blood flow distal to an arterial occlusion in SHR and WKY rats. DESIGN: Occlusion of the middle cerebral artery was chosen because the middle cerebral artery territory is most commonly affected by cerebral infarcts in man. METHODS: Surface and volume densities of capillaries in the neocortex of the middle cerebral artery territory were measured by stereological techniques on histological sections. Fifteen minutes after ligation of the right middle cerebral artery, regional cerebral blood flow was measured autoradiographically by the [14C]-iodoantipyrine method. RESULTS: The capillary density of the neocortex did not differ between the SHR and WKY rats. The blood flow was significantly lower within the middle cerebral artery territory in the SHR than in the WKY rats. CONCLUSIONS: The reduced blood flow distal to the occlusion in SHR is probably a consequence of structural adaptation of arterial resistance vessels, rather than being caused by reduced capillary density.
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| 3. |
- Kahrstrom, J, et al.
(författare)
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A morphometric study of the effect of bilateral cervical sympathetic ganglionectomy on the architecture of pial arteries in spontaneously hypertensive and normotensive rats
- 1994
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Ingår i: Acta Physiologica Scandinavica. - 0001-6772. ; 152:4, s. 407-418
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Tidskriftsartikel (refereegranskat)abstract
- The influence of the cranial sympathetic nerves on the architecture of pial arteries in normo- and hypertension was examined. For this purpose the effect of bilateral superior cervical ganglionectomy was evaluated in normotensive rats (WKY) and stroke-prone spontaneously hypertensive rats (SHRSP). The operations were performed at the age of 1 wk, which is just prior to the onset of ganglionic transmission. The length of the inner media contour was measured and the media cross-sectional area was determined planimetrically, with computerized digitalization of projected photographic images of transversely sectioned pial arteries. Four wk after sympathectomy there was a 20% reduction in media cross-sectional area and a consequent reduction in the ratio between media area and calculated luminal radius in the major pial arteries at the base of the brain in WKY but not in SHRSP. Conversely, in small pial arteries linear regression analysis showed that in WKY subjected to ganglionectomy the relationship between media cross-sectional area and luminal radius was significantly larger in arteries with a radius less than 21 microns compared to untreated WKY. No such effect was seen in the corresponding SHRSP vessels. In addition, the cross-sectional area of the internal elastic membrane (IEM) in the basilar arteries of WKY was measured by means of a computerized image-analysing system. Mean cross-sectional area of the IEM was approximately 45% larger following SE than in control animals. The present findings propose a 'trophic' role for the sympathetic perivascular nerves in large pial arteries of the rat. The increased media-radius ratio in the small pial arteries of the WKY following sympathectomy might reflect a compensatory hypertrophy due to reduced protection from the larger arteries against the pressure load. The inability to detect any morphometrically measurable effect of the sympathectomy in the cerebral arteries of SHRSP is probably explained by a marked growth-stimulating effect of the high pressure load in these animals.
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| 4. |
- Nordborg, C, et al.
(författare)
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Oedema-related tissue damage after temporary and permanent occlusion of the middle cerebral artery
- 1994
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Ingår i: Neuropathology & Applied Neurobiology. - : Wiley. - 1365-2990 .- 0305-1846. ; 20:1, s. 56-65
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Tidskriftsartikel (refereegranskat)abstract
- Eleven adults spontaneously-hypertensive male rats (SHR) were studied 22 h or 7 days after a 2 h unilateral occlusion of the right middle cerebral artery (MCA). Another 11 SHR were studied after 24 h or 7 days of permanent MCA ligation. The brain infarcts were significantly larger (P < 0.05) after permanent occlusion than after a 2 h occlusion. More extensive and widespread vasogenic oedema, emanating from the infarcts, was visualized immunohistochemically in the temporarily-ligated animals and the relative number of astrocytes in their contralateral hemispheres was greater, thereby indicating that the vasogenic oedema influences the degree of gliosis. An immunopositivity for albumin but not for fibrinogen extended via the white matter into the ipsilateral thalamic nuclei, where cytolytic nerve cell damage, severely shrunken and karyorrhectic nerve cells as well as gliosis were found one week after permanent and temporary MCA ligation. The histological changes in the thalamus indicated a difference in timing between lateral and medial parts of the lesion as well as between temporarily- and permanently-ligated SHR. These findings together with the close spatial correlation with albumin immunoreactivity indicate that the spread of extravasated plasma constituents or degradation products with the oedema bulk flow from the infarct influences the timing, character and extent of thalamic lesions after cerebral infarction.
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| 5. |
- Olmarker, K, et al.
(författare)
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Effects of chondroitinase ABC on intrathecal and peripheral nerve tissue. An in vivo experimental study on rabbits
- 1991
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Ingår i: Spine. - 0362-2436. ; 16:1, s. 43-45
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Tidskriftsartikel (refereegranskat)abstract
- The enzyme chondroitinase ABC has recently been suggested for use in chemonucleolysis. The effects of 200 U ml of chondroitinase ABC were studied on intrathecal and peripheral nerve tissue in rabbits. After the intrathecal (subarachnoid) application of 0.2 ml of either the diluent in the control group (N = 2) or chondroitinase in the study group (N = 4), no neurologic deficit was detected. Compared with the control group, no morphologic changes at the light microscopic level were induced in the spinal cord by chondroitinase. No neurophysiologic differences were detected between tibial nerves after exposure to 1 ml of the diluent (control, N = 8) or chondroitinase (the other leg) for 4 weeks, nor did the study group, compared with the control group, show any morphologic changes in the tibial nerves. Because the concentration of chondroitinase ABC tested was approximately 40 times higher than might be used clinically for chemonucleolysis, the present study indicates a wide margin of safety for unwanted side effects on nerve tissue.
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