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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe the clinical syndrome, medical management, etiology, and neurologic outcome of stroke diagnosed by computed tomographic scan in 11 full-term neonates encountered during a two-year period. Neonatal stroke is relatively common and may appear in the setting of diverse cerebrovascular disorders such as hypoxic-ischemic encephalopathy, polycythemia, acute severe hypertension, and embolization. Repetitive, persistently unifocal motor seizures heralded localized cerebral injuries in eight infants. The majority of patients did not display any other lateralized clinical neurologic signs. An electroencephalogram revealed a focal or lateralized functional central nervous system abnormality in ten cases. All of the initial computed tomographic scans were focally abnormal. However, cranial ultrasound examinations were insensitive to stroke in nine patients. Medical management included careful cardiorespiratory support, correction of coexisting metabolic or system abnormalities, and aggressive administration of anticonvulsants to promptly eliminate seizures. Limited follow-up suggests that many affected infants may enjoy favorable outcomes.
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PMID:Focal motor seizures heralding stroke in full-term neonates. 400 65

Neonatal stroke remains a complex pathophysiologic process that is poorly understood and difficult to investigate. The primary animal model used to study this phenomenon is that of unilateral carotid artery ligation with 2-3 hours exposure to severe hypoxia. A new model of neonatal stroke was developed based on transient middle cerebral artery occlusion without craniectomy. In this model a #6-0 (0.07 mm) nylon filament is passed via the carotid artery to occlude reversibly the middle cerebral artery for 4 hours under conditions of normoxia in 14- to 18-day-old spontaneously hypertensive rat pups. After removal of the filament and reperfusion for 24 hours, the infarct volume was determined using the mitochondrial stain, 2,3,5-triphenyltetrazolium chloride. Using this technique, a neocortical and caudoputamenal infarct affecting 49% of hemispheric volume that measured 180 +/- 29 mm3 (hemisphere volume = 359 +/- 16 mm3, mean +/- SEM) was created in 90% of animals (n = 8) undergoing this procedure. This model has the advantage of being relatively noninvasive, of not requiring global exposure of brain to hypoxia, and of using temporary rather than permanent occlusion. This technique should improve the ability to study the acute and long-term pathophysiology of neonatal stroke, particularly the phenomenon of reperfusion injury, as well as its sequelae in the developing nervous system.
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PMID:A new model of neonatal stroke: reversible middle cerebral artery occlusion in the rat pup. 761 84

Neonatal stroke is a condition that leads to disability in later life, and as yet there is no effective treatment. Recently, erythropoietin (EPO) has been shown to be cytoprotective following brain injury and may promote neurogenesis. However, the effect of EPO on functional outcome and on morphologic changes in neonatal subventricular zone (SVZ) following experimental neonatal stroke has not been described. We used a transient focal model of neonatal stroke in P10 rat. Injury was documented by diffusion weighted MRI during occlusion. Immediately upon reperfusion, either EPO (5U/gm) or vehicle was administered intraperitoneally and animals were allowed to grow for 2 wk. Sensorimotor function was assessed using the cylinder rearing test and then brains were processed for volumetric analysis of the SVZ. Stroke induced SVZ expansion proportional to hemispheric volume loss. EPO treatment markedly preserved hemispheric volume and decreased the expansion of SVZ unilaterally. Furthermore, EPO treatment significantly improved the asymmetry of forelimb use following neonatal stroke. This functional improvement directly correlated with the amount of preserved hemispheric volume. These results suggest EPO may be a candidate in the treatment of neonatal stroke.
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PMID:Erythropoietin improves functional and histological outcome in neonatal stroke. 1587 87

Neonatal stroke is increasingly recognized in preterm and term infants but the ability to study this condition has been limited by the technical challenges in developing suitable animal models. In the current study we report the use of transient filament middle cerebral artery occlusion for 1.5 h in 10-day-old rat pups in which we were able to perform serial magnetic resonance imaging (MRI) studies. Serial MRI was performed immediately after the onset of stroke until 28 days after injury in an 11.7 T scanner using diffusion weighted and T2-weighted images. At 28 days the rat pups were sacrificed and standard histological stains were performed to validate stroke area. Serial behavioral assessments were also performed on the day of each imaging study. The anatomical distribution of stroke was similar to that expected from occlusion of the middle cerebral artery in adult models and represents a specific model of neonatal stroke in contrast to the commonly used model of carotid artery occlusion with 8% hypoxia. The initial stroke volume from MR measurements was 39% of the ipsilateral hemisphere at 0 h post-occlusion, reached a maximum at 24 h (44%) and then decreased in size (17%) with subsequent cavitation by 28 days. Infarction was more visible early with diffusion weighted imaging whereas T2-mapping provided more accurate infarct volumes at later time points. Despite the relatively large infarct volume, we saw little evidence of behavioral neurological deficit suggesting that this may also serve as a model of developmental plasticity and recovery.
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PMID:Serial magnetic resonance imaging in a rat pup filament stroke model. 1687 60

Neonatal stroke outcome studies demonstrate variable findings of either relatively spared intellectual function or persistent impairments. Volumetric measurement of the brain can provide more precise data on lesion-cognition outcomes. We studied 7 children with unilateral focal lesions from prenatal stroke. Whole-brain magnetic resonance imaging scans were analyzed to produce volumes of cortical gray matter, total white matter, cerebrospinal fluid, lesion, and lesion constricted fluid, and we ascertained the relationship of morphometric variables to intellectual and clinical outcome. Children with cystic encephalomalacia plus atrophy had poorer outcomes than children with atrophy or gliosis alone. These children also demonstrated the largest lesion size, smallest gray matter volume, and greatest proportion of hyperintense white matter in the affected hemisphere. Findings suggest that the type and size of the lesion, in addition to the integrity of white matter and residual cortex, may be better predictors of intellectual functioning than either of these indices alone.
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PMID:Brain structure in prenatal stroke: quantitative magnetic resonance imaging (MRI) analysis. 1771 76

Neonatal stroke leads to mortality and severe morbidity, but there is no effective treatment currently available. Erythropoietin (EPO) has been shown to promote cytoprotection and neurogenesis and decrease subventricular zone morphologic changes following brain injury. The long-term cellular response to EPO has not been defined, and local changes in cell fate decision may play a role in functional improvement. We performed middle cerebral artery occlusion in P10 rats. EPO treatment (5 U/g i.p.) significantly preserved hemispheric brain volume 6 weeks after injury. Furthermore, EPO increased the percentage of newly generated neurons while decreasing newly generated astrocytes following brain injury, without demonstrating long-term differences in the subventricular zone. These results suggest that EPO may neuroprotect and direct cell fate toward neurogenesis and away from gliogenesis in neonatal stroke.
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PMID:Erythropoietin enhances long-term neuroprotection and neurogenesis in neonatal stroke. 1776

Neonatal stroke is increasingly recognized in preterm and term infants, and the rate of arterial ischemic infarction occurring around the time of birth is as high as the annual incidence of large-vessel ischemic stroke in adults. Thus, neonatal stroke is a major contributor to perinatal morbidity and mortality, and a considerable number of these children will develop long-term neurodevelopmental disabilities. Our ability to investigate this situation has been limited by the technical challenges in developing suitable animal models. Our objective is to describe recent evidence in relation to animal models of neonatal stroke. In addition, we review and report potential neuroprotective strategies specific to neonatal stroke, with a focus on erythropoietin and cardiotrophin-1 because of their potential role in protection as well as repair.
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PMID:Animal models of neonatal stroke and response to erythropoietin and cardiotrophin-1. 1803 63

Neonatal stroke presents with seizures and results in neurologic morbidity, including epilepsy, hemiparesis, and cognitive deficits. Stem cell-based therapy offers a possible therapeutic strategy for neonatal stroke. We developed an immature mouse model of stroke with acute seizures and ischemic brain injury. Postnatal day 12 CD1 mice received right-sided carotid ligation. Two or 7 days after ligation, mice received an intrastriatal injection of B5 embryonic stem cell-derived neural stem cells. Four weeks after ligation, hemispheric brain atrophy was measured. Pups receiving stem cells 2 days after ligation had less severe hemispheric brain atrophy compared with either noninjected or vehicle-injected ligated controls. Transplanted cells survived, but 3 out of 10 pups injected with stem cells developed local tumors. No difference in hemispheric brain atrophy was seen in mice injected with stem cells 7 days after ligation. Neural stem cells have the potential to ameliorate ischemic injury in the immature brain, although tumor development is a serious concern.
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PMID:Neural stem cells reduce brain injury after unilateral carotid ligation. 1820 88

Neonatal stroke occurs in 1 in 2300-5000 live births, the incidence of which is lower than that in adults, but still higher than that in childhood. The higher incidence of perinatal stroke in preterm and term infants compared to stroke in childhood may be partly explained by higher detection rates using routine fetal ultrasound and postnatal cranial sonography. In addition, there is greater availability of magnetic resonance imaging (MRI) for neuroimaging in preterm and full-term infants, which is due in part to the availability of MR-compatible incubators and MR systems at or near the neonatal intensive care unit. In addition, the wide range of MR techniques, such as T2-, diffusion- and susceptibility-weighted imaging allows improved visualization and quantification of neonatal stroke or hypoxic-ischemic injury. This chapter reviews the MR neuroimaging modalities that actually assist the clinician in the detection of neonatal stroke.
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PMID:Magnetic resonance imaging in neonatal stroke. 1963 9

Neonatal stroke presents with seizures that are usually treated with phenobarbital. We hypothesized that anticonvulsants would attenuate ischemic injury, but that the dose-dependent effects of standard anticonvulsants would impact important age-dependent and injury-dependent consequences. In this study, ischemia induced by unilateral carotid ligation in postnatal day 12 (P12) CD1 mice was immediately followed by an i.p. dose of vehicle, low-dose or high-dose phenobarbital. Severity of acute behavioral seizures was scored. 5-Bromo-2'-deoxyuridine (BrdU) was administered from P18 to P20, behavioral testing performed, and mice perfused at P40. Atrophy quantification and counts of BrdU/NeuN-labeled cells in the dentate gyrus were performed. Blood phenobarbital concentrations were measured. 30mg/kg phenobarbital reduced acute seizures and chronic brain injury, and restored normal weight gain and exploratory behavior. By comparison, 60mg/kg was a less efficacious anticonvulsant, was not neuroprotective, did not restore normal weight gain, and impaired behavioral and cognitive recovery. Hippocampal neurogenesis was not different between treatment groups. These results suggest a protective effect of lower-dose phenobarbital, but a lack of this effect at higher concentrations after stroke in P12 mice.
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PMID:Different effects of high- and low-dose phenobarbital on post-stroke seizure suppression and recovery in immature CD1 mice. 2148 68


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