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Träfflista för sökning "WFRF:(Johansson Patrik) srt2:(1992-1994)"

Sökning: WFRF:(Johansson Patrik) > (1992-1994)

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1.
  • Grabowski, Martin, et al. (författare)
  • Fetal neocortical grafts implanted in adult hypertensive rats with cortical infarcts following a middle cerebral artery occlusion: ingrowth of afferent fibers from the host brain
  • 1992
  • Ingår i: Experimental Neurology. - 0014-4886. ; 116:2, s. 105-121
  • Tidskriftsartikel (refereegranskat)abstract
    • This study is focused on the survival of fetal neocortical grafts placed in the infarcted adult host cortex of the spontaneously hypertensive rat and describes the ability of host axonal regeneration into the graft after a focal ischaemic lesion. Five to seven days following ligation of the right middle cerebral artery, dissociated neocortical primordium from fetuses of gestational age 12-18 days was implanted into the infarcted cortical area. Surviving transplants were seen in all rats, although grafts derived from gestational age 12-14 days displayed an irregular morphology rich in sinusoid-like cavities and containing fewer cells of apparently mature neuronal morphology. Grafts from older donors contained perikarya of neuronal appearance; however, they lacked normal cortical lamination. Ten days postgrafting, fibers stained by acetylcholinesterase histochemistry, dopamine-beta-hydroxylase, and 5-hydroxytryptamine immunohistochemistry were found in the grafts, and by 10-23 weeks after transplantation the fiber density had increased substantially. When the retrograde tracer Fluoro-Gold was injected into the grafted tissue, labeled cells were found in several subcortical nuclei of the host, including the nucleus basalis of Meynert, ventral pallidum, thalamus, dorsal raphe, locus coeruleus, as well as the ipsilateral and contralateral neocortex. This study shows that grafts of dissociated neocortical tissue exhibit good survival and growth potential when implanted into infarcted neocortex and that several nerve fiber systems of the adult host have a regenerative capacity sufficient to innervate the grafted tissue.
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2.
  • Grabowski, Martin, et al. (författare)
  • Functional integration of cortical grafts placed in brain infarcts of rats
  • 1993
  • Ingår i: Annals of Neurology. - : Wiley. - 1531-8249 .- 0364-5134. ; 34:3, s. 362-368
  • Tidskriftsartikel (refereegranskat)abstract
    • Five to 6 days after a right middle cerebral artery occlusion, a cell suspension of fetal neocortex was grafted into the infarcted area of adult spontaneously hypertensive rats. Three to 17 months later, functional integration of the grafts into the afferent somatosensory pathway was tested using the 2-[14C]deoxyglucose method for estimation of glucose utilization. Grafted rats (n = 8) and control rats (n = 5) with no arterial occlusion were stimulated in the left vibrissal region resulting in an increased glucose utilization in the left trigeminal sensory nucleus and the right ventroposterior nucleus of the thalamus, whereas the same regions in a group (n = 5) of nonstimulated grafted rats were not activated. Glucose uptake in the right somatosensory cortex of control rats was 96 +/- 5 (mean +/- SEM) mumol/100 gm/min. Neocortical grafts consumed less glucose than cortex in control rats but the vibrissae-stimulated group displayed a 110% higher value than the nonstimulated grafted group (32 +/- 5 vs 15 +/- 2, p < 0.05). We conclude that graft glucose metabolism is increased following stimulation of the host somatosensory pathway, which demonstrates that transplanted neurons can be functionally integrated with neural circuitries of the host after an ischemic insult.
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3.
  • Grabowski, Martin, et al. (författare)
  • Paw-reaching, sensorimotor, and rotational behavior after brain infarction in rats
  • 1993
  • Ingår i: Stroke: a journal of cerebral circulation. - 1524-4628. ; 24:6, s. 889-895
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND AND PURPOSE: Functional tests that are stable and consistent over time are an advantage for long-term evaluation of treatment in experimental stroke research. Because little information on this subject is available in rodents with focal cerebral ischemia, we investigated the outcome of three behavioral tests for a period of 3 months after the insult. METHODS: Spontaneously hypertensive rats were sham-operated (n = 27) or underwent an occlusion (n = 36) of the right middle cerebral artery. Before surgery all rats were tested for amphetamine-induced rotational behavior, and half of the rats were trained in a paw-reaching task. One, 2, and 3 months after surgery the tests were repeated, together with a test for sensorimotor function. Infarct size was measured morphometrically. RESULTS: In the lesion group, total hemisphere area was reduced by 22%, caudate putamen by 47%, and the thalamus by 24%. Contralateral to the lesion, paw-reaching was highly impaired, regardless of whether or not the rats had been pretrained, and lesion size correlated significantly to paw-reach performance. Ipsilateral rotation increased and sensorimotor function recovered with time in infarcted rats. CONCLUSIONS: In contrast to amphetamine-induced rotation and sensorimotor behavior, the paw-reaching test provides a stable behavioral parameter after a middle cerebral artery occlusion. Moreover, the lesion-induced deficit in paw-reaching is highly correlated to the extent of the infarct, suggesting that this test is useful in evaluating treatment effects for a longer period of time.
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4.
  • Grabowski, Martin, et al. (författare)
  • Survival of fetal neocortical grafts implanted in brain infarcts of adult rats: the influence of postlesion time and age of donor tissue
  • 1994
  • Ingår i: Experimental Neurology. - : Elsevier BV. - 0014-4886. ; 127:1, s. 126-136
  • Tidskriftsartikel (refereegranskat)abstract
    • We have previously found that fetal cortex taken from 16- to 18-day-old donors survives grafting to the infarcted cortex 5-7 days after middle cerebral artery occlusion. The present study was undertaken to examine the effect on graft survival of varying the age of the fetal donor tissue and the time between vessel occlusion and graft implantation. First, a cell suspension of neocortical tissue was grafted from fetuses aged 15, 17, or 20 gestational days to the infarcted cortex of hypertensive rats which had undergone arterial occlusion 5-7 days earlier. There were no significant differences in the mean size or general morphology assessed in Nissl- and acetylcholinesterase-stained sections between the groups. Second, neocortical tissue was grafted from fetuses aged 15 gestational days to the infarcted cortex at different times following arterial occlusion. When surgery was delayed until 5-7 days, 3 weeks, or 8 weeks postocclusion, graft survival was significantly better than when implanted 1 day postocclusion. Implantation after 3 weeks yielded grafts that also were significantly larger than those in rats grafted 5-7 days after cortical infarction. The results indicate that there is no crucial upper donor age limit for dissociated fetal neocortical grafts in terms of graft survival and volume. Furthermore, a delay between lesion and transplantation is desirable in this stroke model. The host brain environment seems to be most hospitable around 3 weeks after arterial occlusion.
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5.
  • Grabowski, Martin, et al. (författare)
  • Vascularization of fetal neocortical grafts implanted in brain infarcts in spontaneously hypertensive rats
  • 1992
  • Ingår i: Neuroscience. - 1873-7544. ; 51:3, s. 673-682
  • Tidskriftsartikel (refereegranskat)abstract
    • The vascularization of neural grafts in ischemic brain was studied in spontaneously hypertensive rats grafted with a suspension of fetal neocortical tissue into the infarcted area five to six days after ligation of the middle cerebral artery. The brain vasculature was examined by scanning electron microscopy of corrosion vascular casts and the cortical microvasculature was stereologically quantified in light microscopy three months after the occlusion. Patent anastomoses were present between the middle cerebral artery distal to occlusion and the proximal part, as well as to the anterior and posterior cerebral arteries, in both grafted and non-grafted rats. A vascular plexus covering the infarct cavities and the grafts contained leptomeningeal vessels intermingled with a thin capillary network which is not normally found on the brain surface. The graft vessels were derived from this vascular plexus. The regular pattern of arterioles and venules penetrating from the cortical surface in normal neocortex was absent in the grafts but the capillary morphology was similar in both types of tissue. The grafts had a lower capillary density than normal tissue and lacked the laminar distribution of capillaries characteristic of normal neocortex. The results demonstrate the plasticity of the vascular system where remodeling of the vascular tree after an ischemic insult provides suitable conditions for the vascularization of neocortical grafts.
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  • Resultat 1-5 av 5
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tidskriftsartikel (5)
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refereegranskat (5)
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Brundin, Patrik (5)
Johansson, Barbro (5)
Grabowski, Martin (5)
Christofferson, R H (1)
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Medicin och hälsovetenskap (5)

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