| 1. |
- Grabowski, Martin, et al.
(författare)
-
Influence of an enriched environment and cortical grafting on functional outcome in brain infarcts of adult rats
- 1995
-
Ingår i: Experimental Neurology. - : Elsevier BV. - 0014-4886. ; 133:1, s. 96-102
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this work was to study if enriched housing conditions and fetal neocortical transplantation could enhance the functional outcome after focal brain ischemia in adult rats. The right middle cerebral artery (MCA) was ligated in 34 inbred, spontaneously hypertensive male rats, which were then randomly divided into three groups. Groups A and B were transferred to an enriched environment, i.e., a large cage with opportunities for various activities but not forcing the rats to do any particular tasks; group C was kept in standard laboratory cages. Three weeks after the MCA occlusion blocks of fetal neocortical tissue (Embryonic Day 17) were transplanted to the infarct cavity in groups B and C. Rats in group A (n = 11) and group B (n = 11) performed equally well and significantly better than rats in group C (n = 10) when placed on an inclined plane and when traversing a rotating pole 6 and 9 weeks after the MCA occlusion and in a leg placement test at 9, but not 6 and 12 weeks. Skilled forelimb function did not differ between the groups. Infarct size and thalamic atrophy did not differ between the groups and graft size was similar in group B and C. There was no correlation between infarct size and motor function in any of the tests in rats housed in an enriched environment. Since the environment can significantly alter functional outcome without reducing infarct size we suggest that more attention should be given to the role of the laboratory environment and to long term behavioral outcome in experimental stroke.
|
|
| 2. |
- Grabowski, Martin, et al.
(författare)
-
Neocortical grafts placed in the infarcted brain of adult rats: few or no efferent fibers grow from transplant to host
- 1995
-
Ingår i: Experimental Neurology. - : Elsevier BV. - 0014-4886. ; 134:2, s. 273-276
-
Tidskriftsartikel (refereegranskat)abstract
- The present study examines the capacity of fetal neocortical grafts placed in a brain infarct to exchange axonal projections with the host brain. Five to 7 days after a middle cerebral artery occlusion in adult spontaneously hypertensive rats, dissociated neocortical primordium from fetuses of gestational age 15-16 days was implanted into the infarcted area. Four to 11 months later, the neural tracers Phaseolus vulgaris-leucoagglutinin and Fluoro-Gold were injected in the grafts and host neocortex. An extensive axonal network was present in the transplants but only one of eight rats with appropriate placed injections displayed efferent connections from transplant to host. The sparse axonal outgrowth indicates major limitations for fetal rat cortical grafts to form connections with host neural circuitries after an ischemic insult.
|
|
| 3. |
- Lindgren, Arne, et al.
(författare)
-
Plasma homocysteine in the acute and convalescent phases after stroke
- 1995
-
Ingår i: Stroke: a journal of cerebral circulation. - 1524-4628. ; 26:5, s. 795-800
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Stroke patients frequently manifest moderate hyperhomocysteinemia. In most published studies, plasma homocysteine was measured at least 1 month after stroke (or the interval was not reported). To determine whether plasma homocysteine concentrations change in the acute phase, we compared acute-phase values with both convalescent-phase and control values. METHODS: Plasma homocysteine concentrations were measured in the acute phase (mean, 2 days after stroke onset) in 162 first-ever stroke patients aged 50 years or more (median, 75 years) and again at a median interval of 583 days (range, 460 to 645 days) after stroke onset in a subgroup of 17 patients, with values for 60 age-matched subjects serving as controls. Twenty of the control subjects were reexamined 2 to 3 years after their initial examination. RESULTS: The median plasma homocysteine concentration was 13.4 mumol/L in the patient group compared with 13.8 mumol/L for control subjects (NS, Mann-Whitney U test) and increased from 11.4 mumol/L in the acute phase to 14.5 mumol/L in the convalescent phase in the subgroup of patients examined twice (P < .01, Wilcoxon signed rank test). In the 20 reexamined control subjects, no significant change over time in plasma homocysteine concentration was found. CONCLUSIONS: The post-acute-phase increase in plasma homocysteine may explain why higher values were obtained for stroke patients than for control subjects in previous studies. Possible reasons for the variation in plasma homocysteine concentrations over time are (1) an acute-phase reduction secondary to a decrease in plasma albumin and (2) an increase in plasma homocysteine during the convalescent phase due to modified vitamin intake and/or lifestyle. The timing of plasma homocysteine measurements relative to stroke onset is a factor to be considered in the interpretation of results.
|
|
| 4. |
- Ohlsson, Anna-Lena, et al.
(författare)
-
Environment influences functional outcome of cerebral infarction in rats
- 1995
-
Ingår i: Stroke: a journal of cerebral circulation. - 1524-4628. ; 26:4, s. 644-649
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: The purpose of this study was to determine whether preoperative and postoperative enrichment of the environment can enhance the functional outcome after cerebral infarction in rats. METHODS: The right middle cerebral artery was ligated in adult spontaneously hypertensive male rats, and the functional outcome was studied for 12 weeks after the operation. Three groups were compared: A, rats kept in individual cages before and after the operation (n = 9); B, rats kept in individual cages before the operation but transferred to an enriched environment after the operation (n = 10); and C, rats kept in an enriched environment all the time (n = 12). The enriched environment consisted of a large cage with opportunities for various activities, but rats were not forced to do any particular tasks. RESULTS: Rats kept in an enriched environment (groups B and C) performed significantly better than rats in group A in a leg-placement test, beam walking, walking on a rotating pole, and climbing. The infarct size and thalamic atrophy did not differ among the groups. CONCLUSIONS: The laboratory environment is important for the functional outcome in brain ischemia. We hypothesize that an enriched environment may stimulate mechanisms that enhance brain plasticity after focal brain ischemia.
|
|
