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

A severely anaemic, but asymptomatic patient, who is a heterozygous carrier of haemoglobin Hammersmith (beta42 (CD1) phenylalanine - Serine), has been studied to elucidate the mechanisms resulting in physiological compensation for the anaemia. Four factors have been investigated: the oxygen affinity of her blood, the cardiac output at rest and during exercise, the blood gas indices, and pulmonary function. It was found that due to the presence of Heinz bodies within the erythrocytes, the level of functional, haemoglobin was considerably less (50 g/l) than that measured by standard methods (87 g/l). In addition a moderate degree of arterial hypoxaemia (arterial oxygen tension = 10.7 kPa (80.4 mmHg) was present which could not be explained on the basis of abnormal pulmonary function. Both of these factors would result in tissue hypoxia, but the finding of consistently normal oxygen tensions ('mixed' venous oxygen tension = 5.4 kPa (40.3 mmHg) in blood obtained from the right atrium, suggested that hypoxia was not present. This was explained by a decreased whole blood oxygen affinity (P50 = 4.6 kPa (34.5 mmHg) at pH 7.4) and an increase in the cardiac index (5.3 L.min.-1m-2). The latter was the result of an increased stroke volume (125 - 135 ml), the heart rate being normal (63/min.). During moderate exercise, further increases at cardiac output were brought about by a change in heart rate alone. It has been calculated that the decrease in whole blood oxygen per se could not account for adequate tissue oxygenation. This is confirmed by the finding of an increased cardiac output in this patient. It is suggested that in any severe haemolytic anaemia, even if the whole blood oxygen affinity is low, cardiac output is probably increased to achieve complete physiological compensation.
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PMID:Compensatory mechanisms for the severe anaemia caused by haemoglobin Hammersmith. 93 44

High resolution magnetic resonance angiography (MRA) revealed highly variable arterial cerebrovascular structures in mice from different strains and within the same strain. C57Black/6 mice presented small unilateral anastomoses between the posterior cerebral and the superior cerebellar arteries. Well developed, either unilateral or bilateral, posterior communicating arteries (PcomA) were detected on CBA mice. The arterial structure of CD1 mice ranged from no detectable anastomoses to well developed, unilateral PcomAs. SV-129 mice showed significantly shorter middle cerebral arteries compared to the other strains, and clear bilateral anastomoses between the posterior cerebral and the superior cerebellar arteries. Because of its non-invasiveness, MRA may be of importance in murine stroke studies by enabling the selection of animals and/or the side for performing the surgical intervention, and the verification of its success. Magn Reson Med 44:252-258, 2000.
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PMID:High resolution magnetic resonance angiography non-invasively reveals mouse strain differences in the cerebrovascular anatomy in vivo. 1091 24

Ischemic brain injury from stroke is an important cause of disability in infants and children, but current experimental models for the disorder are complex. These preparations require occlusion of small intracerebral vessels or common carotid artery ligation combined with exposure to reduced levels of oxygen. Unilateral carotid artery ligation alone was sufficient to cause brain injury in more than 70% of 12-day-old CD1 mice. Using a blinded behavioral rating scale of seizure activity in mice, a direct, highly significant correlation between the severity of seizures over the 4-hour period after ligation and the severity of histologic brain injury 7 days later (Spearman's rho = 0.835, P < 0.001) was documented. This study presents the first model of stroke in immature mice produced by unilateral carotid artery ligation alone, and the first to demonstrate a clear correlation between acute ischemia-induced seizures and brain injury. This new model should be useful for examining the pathogenesis of stroke in the immature brain and the potential contribution of seizures to final outcome.
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PMID:A new model of stroke and ischemic seizures in the immature mouse. 1546 36

Besides aspirin several new drugs for inhibition of platelet aggregation and 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibition are used in secondary stroke prevention. Pharmacology and clinical effects, however, are not fully explained by current understanding of underlying mechanisms. Population spike amplitude (PSAP), an established marker of slice integrity, was measured during hypoxia and recovery thereof in hippocampal slices from control CD1 mice (25-35 g) and animals pretreated in vivo with a single i.p. injection of clopidogrel, ticlopidine, or atorvastatine at different time intervals and dosages. Posthypoxic recovery of PSAP was 20 +/- 35% in control CD1 mice. Upon pretreatment with clopidogrel (1-24 h, 0.5-2 mg/kg body weight) an increase up to 81 +/- 20% (p < 0.01 to control) was observed at 1h interval and 1mg/kg. Application of ticlopidine (1-24 h, 1-4 mg/kg body weight) resulted in an improvement of posthypoxic recovery to 61 +/- 41% (p < 0.05 to control) while administration of atorvastatine (1-24 h, 1-4 mg/kg body weight) caused an increase up to 87 +/- 31% (p < 0.01 to control) at 1h interval and 2 mg/kg. On application of these substances in vitro the NADH autofluorescence spectrum in hippocampal slices is blue-shifted suggesting an alteration of oxidative metabolism. The present data demonstrate a shared neuroprotective effect of agents known to inhibit platelets (acetylsalicylic acid, clopidogrel, and ticlopidine) and HMG-CoA reductase (atorvastatine). The time course of this neuroprotective action in the current experimental study (onset within an hour, duration of several hours in contrast to several days) resembles clinical practice in dosing these substances. We hypothesize that an increase of hypoxic tolerance resulting from mild mitochondrial inhibition by these substances is a principal constituent of the effectiveness of these drugs.
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PMID:Improved posthypoxic recovery in vitro on treatment with drugs used for secondary stroke prevention. 1575 83

Premature infants with placental infection and adult stroke patients with fever have worse outcomes following intracerebral hemorrhage (ICH). We hypothesized that immune pre-activation would aggravate brain injury in mouse brain following ICH. The immune system of 2-day, 10-day and 7-week young adult CD1 mice was stimulated by intraperitoneal injection of concanavalin A (ConA), lipopolysaccharide (LPS) or polyinosinic-polycytidilic acid (PolyI:C) 12 h prior to intracerebral injection of blood. Two days later, brain damage and inflammation were worse in 2-day mice that had received LPS. The other agents had less consistent effects in 2-day mice. Brain damage in young adults was aggravated less after immune stimulation. These data suggest that immune pre-activation modifies hemorrhagic brain injury in immature mouse brain.
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PMID:Immune pre-activation exacerbates hemorrhagic brain injury in immature mouse brain. 1596 38

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

Stroke in the neonatal brain is an important cause of neurologic morbidity. To characterize the dynamics of neural progenitor cell proliferation and maturation after survival delays in the neonatal brain following ischemia, we utilized unilateral carotid ligation alone to produce infarcts in postnatal day 12 CD1 mice. We investigated the neurogenesis derived from the sub-ventricular zone and the sub-granular zone of the dentate gyrus subsequent to injury. Newly produced cells were labeled by bromodeoxyuridine at approximately 1 week (P18-20) after the insult by 5 i.p. injections (each 50 mg/kg). Subsequent migration and differentiation of the newborn cells was investigated at postnatal day 40 by immunohistochemistry for molecular neuronal and glial cell-lineage markers and BrdU incorporation. Cresyl violet stain demonstrated massive loss of neurons in the ipsilateral septal hippocampus in the CA3 and CA1 regions associated with atrophy. Total counts of new cells were significantly lowered not only in the ipsilateral injured but also the contralateral uninjured hippocampi and correlated with the lesion induced atrophy. Bilateral percent neuronal commitments in the dentate gyri however, were not significantly different from control. New cell densities in the neocortex and striatum increased bilaterally after neonatal stroke. The predominantly non-neuronal commitment of the SVZ-derived new cells was similar to the percentage of non-neuronal commitment in controls. In conclusion, neurogenesis occurring at 1 week after neonatal ischemia in the model maintained cell-lineage commitment patterns similar to sham controls. However, the total number of hippocampal SGZ-derived new neurons was reduced bilaterally; in contrast, the SVZ-derived neurogenesis was amplified.
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PMID:Neurogenesis and neuronal commitment following ischemia in a new mouse model for neonatal stroke. 1838 98

Stroke is a major cause of neurologic morbidity in neonates and children. Because neonatal and pediatric stroke frequently present with seizures, the question of which anticonvulsant best blocks acute ischemic seizures and reduces injury is clinically relevant. The purpose of this study was to determine the extent to which gabapentin is neuroprotective and suppresses acute seizures in this model of ischemic injury in the immature brain. Postnatal day 12 CD1 mice underwent right common carotid artery ligation and immediately after ligation received a 0, 50, 100, 150, or 200 mg/kg dose of gabapentin intraperitoneally. Acute seizure activity was behaviorally scored and hemispheric brain atrophy measured. In vehicle-treated mice, severity of acute seizures correlated with hemispheric brain atrophy 4 wks later. Gabapentin significantly decreased acute seizures at 200 mg/kg and reduced brain atrophy at doses of 150 and 200 mg/kg but not at lower doses. These results suggest that gabapentin effectively reduces acute seizures and injury after ischemia in the immature brain. When analyzed by animal sex, the data suggest that gabapentin may more effectively reduce acute seizures and injury in male pups vs. female pups.
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PMID:Gabapentin neuroprotection and seizure suppression in immature mouse brain ischemia. 1839 49

The feasibility of blood-pool pinhole ECG gated SPECT was investigated in healthy mice to assess right and left ventricular function analysis. Anaesthetized (isoflurane 1-1.5%) adult CD1 mice (n=11) were analyzed after intravenous administration of 0.2 ml of 550 MBq of (99m)Tc human albumin. For blood-pool gated SPECT imaging, 48 ventral step and shoot projections with eight time bins per RR over 180 degrees with 64 x 64 word images were acquired with a small animal gamma camera equipped with a pinhole collimator of 12 cm in focal length and 1.5 mm in diameter. For appropriate segmentation of right and left ventricular volumes, a 4D Fourier analysis was performed after reconstruction and reorientation of blood-pool images with a voxel size of 0.55 x 0.55 x 0.55 mm(3). Average right and left ejection fractions were respectively 52+/-4.7% and 65+/-5.2%. Right end diastolic and end systolic volumes were significantly higher compared with the corresponding left ventricular volumes (P<0.0001 each). A linear correlation between right and left stroke volumes (r=0.9, P<0.0001) was obtained and right and left cardiac outputs were not significantly different 14.2+/-1.9 and 14.1+/-2 ml/min, respectively.
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PMID:Assessment of right and left ventricular function in healthy mice by blood-pool pinhole gated SPECT. 1872 82

Stroke in term neonates remains a significant cause of long-term neurological morbidity. This study was designed to assess the relationships between ischemic stroke induced by permanent unilateral carotid ligation in P12 CD1 mice and the structural and functional outcomes in the young mice as a consequence. After P12 ischemic strokes, mice were behaviorally tested using accelerated rotorod, spontaneous alternation on a T-maze, open-field, and cylinder tests between P33 and P39. Brain injury was scored by histology at P40 with cresyl violet-stained coronal sections and computerized quantification of the ischemic injury. The ligation-injured mice were not different from controls on cylinder testing for asymmetric use of their forelimb, or on rotorod measures. In the spontaneous alternation task, however, injured mice demonstrated significantly lower rates of alternation indicating a deficit in working memory. Open-field testing repeated on two consecutive days revealed that the ligated mice were less active than the controls and that they failed to habituate to the open field environment between sessions indicating a learning deficit. Overall, our results demonstrate that ischemia induced by our neonatal stroke model produces behavioral deficits that are consistent with the brain injury.
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PMID:Chronic brain injury and behavioral impairments in a mouse model of term neonatal strokes. 1876 Oct 39


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