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PubMedDate not supplied

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy: MR findings.

PURPOSE: To describe the MR appearances of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. METHODS: MR examinations were performed on 15 family members (both symptomatic and asymptomatic). The phenotype was defined by the presence of abnormalities on MR scanning in genetically susceptible individuals. RESULTS: There were 10 abnormal and 5 normal MR scans. Three subjects with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy had moderate or severe neurologic deficits, 4 had transient focal neurologic symptoms, 2 had migraine, and 1 was asymptomatic (all these had abnormal MR scans). Only 1 subject with migraine had a normal MR. Four other asymptomatic family members had normal scans. Two main abnormalities emerged. First, small, linear, and punctate lesions were identified in the periventricular white matter, brain stem, basal ganglia, and thalamus. Second, large confluent patches of abnormal tissue were present in subcortical regions that often were symmetric and had a tendency to occur in the temporal lobes. CONCLUSIONS: The diffuse myelin loss and small infarcts that cause cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy are well demonstrated with MR. Presymptomatic abnormalities can be seen on MR.

Adult↗
PubMed2003

[Role of PPARgamma in the development of the central nervous system].

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor that plays a central role in adipocyte differentiation and insulin sensitivity. Recently, a diversity of the action of PPARgamma on many other cell types or organs is indicated. We summarize here the possible role of PPARgamma in the development of the murine central nervous system. Expressions of PPARgamma in newborn or adult mouse brain are extremely low, but high in embryo or fetal mouse brain. Furthermore, we investigated the role of PPARgamma in proliferation or differentiation of neural stem cells (NSCs) isolated from murine embryonic brains, because NSCs are considered to be a major source of neurons in developmental brains. Administrations of PPARgamma-specific ligands on the NSCs from wild-type mice resulted in the stimulation of cell growth. On the other hand, administration of PPARgamma-antagonist showed the cell death and apoptosis of NSCs. These results may indicate that PPARgamma plays an important role during the early stage of the development of the central nervous system.

Animals↗
PubMed1996

Decreased gene expression of neuronal nitric oxide synthase in hypothalamus and brainstem of rats in heart failure.

Nitric oxide may act at autonomic sites in the brain to regulate sympathetic outflow. Our goal was to determine whether gene expression of the neuronal isoform of nitric oxide synthase (nNOS) is altered in discrete autonomic brain regions of rats in the chronic phase of heart failure compared to sham-operated control rats. Experiments were performed in rats 4 to 5 weeks after left coronary artery ligation. Histological data indicated that there was a 39% outer and a 45% inner infarct of the left ventricular myocardium in the heart failure group. The myocardium in sham-operated rats showed no observable damage. Total RNA was purified from microdissected brain tissue blocks containing hypothalamus, dorsal pons, dorsal medulla, rostral ventrolateral medulla, and caudal ventrolateral medulla. Changes in nNOS mRNA were semiquantified in each region using reverse transcription-polymerase chain reactions in which known concentrations of deletion mutant of the gene were coamplified as an internal standard. Compared with controls, significant decreases in nNOS mRNA levels were found in hypothalamus (19%), dorsal pons (43%) and dorsal medulla (34%) of rats with heart failure. There were no statistically significant differences in nNOS mRNA levels in rostral or caudal ventrolateral medulla between the control and heart failure groups. Concomitant with the changes nNOS gene expression in central sites, the plasma concentration of norepinephrine was significantly elevated in rats with heart failure compared to sham-operated control rats. Our results show that heart failure is associated with decreases in nNOS gene expression in at least three regions of the brain and with increased sympathetic outflow to the periphery. The decreased NO production that is likely associated with the decreases in nNOS gene expression may lead to the increased sympathetic drive seen in chronic heart failure.

Animals↗
PubMed1977

Auditory evoked brain stem potentials in a case of "locked-in" syndrome.

Auditory evoked brain stem potentials were measured in a patient with occlusion of the basilar artery about 7 mm above its origin, resulting in the "locked-in" syndrome due to infarction at the junction of the lower one third and upper two thirds of the pons. The first three waves of the evoked response originating from the acoustic nerve and auditory nuclei in the caudal pons were normal in wave form, peak latency, and voltage level. Waves IV and V, generated in the region of the lateral lemniscus and inferior colliculus in rostral pons and caudal midbrain, demonstrated prolonged peak latency and reduced voltage, indicative of slowed neural conduction in the pons above the level of the superior olivary complex. These findings suggest that auditory evoked potential recordings may have considerable value in the localization of brain stem disorders.

Acoustic Stimulation↗
PubMed1997

Detection of subtle changes in the brains of infants and children via subvoxel registration and subtraction of serial MR images.

PURPOSE: To compare conventional two-dimensional multisection images with registered three-dimensional volume and subtraction images for detecting subtle changes in the brains of infants and children. METHODS: Twenty-six patients (24 with hemorrhagic/ischemic lesions) and one each with perinatal infection and Sturge-Weber disease were examined on two or more occasions with conventional multisection T1- and T2-weighted sequences as well as with 3-D T1-weighted volume sequences. A registration program was used to match the volume images to subvoxel dimensions, and subtracted images (second volume set minus the first) were obtained. The multisection images were compared with the 3-D and subtracted images and graded for detection of changes in a variety of brain structures. RESULTS: In 16% to 33% of comparisons of different structures, the multisection images and the 3-D registered and subtracted images showed changes equally well. The 3-D registered and subtracted images were better than the multisection images in 67% to 84% of comparisons for detection of changes in the cerebral hemispheres, ventricles, brain stem, cerebellum, and in lesions. Statistically significant differences were found between the graded performance of the registered 3-D images and the conventional 2-D images in detecting cerebral infarction and hypoxic ischemic encephalopathy. In the late phase following neonatal cerebral infarction (1 to 11 months), the 3-D registered and subtracted images revealed growth of the brain at the margins of the lesions. CONCLUSION: Subvoxel registration of serial MR images may be of value in detecting subtle changes in the brains of infants and children.

Brain↗
PubMed2003

Survivin-dependent angiogenesis in ischemic brain: molecular mechanisms of hypoxia-induced up-regulation.

Approaches to regulating angiogenesis in the brain, which may diminish parenchymal damage after stroke, are lacking. Survivin, the inhibitor of apoptosis protein, is up-regulated in vitro in vascular endothelial cells by angiogenic factors, including vascular endothelial cell growth factor (VEGF). To evaluate the in vivo role of survivin in the brain in response to hypoxia/ischemia, we used a mouse model of stroke and show that 2 days after permanent middle cerebral artery occlusion, survivin is uniquely expressed by microvessels that form in the peri-infarct and infarct regions. The extent of vascularization of the infarct is dependent on expression of survivin, since vessel density is significantly reduced in mice with heterozygous deficiency of the survivin gene (survivin+/- mice), even though infarct sizes were not different. Hypoxia alone induces survivin expression in the brain, by cultured endothelial cells and by embryonic stem cells, but this response is at least partially independent of VEGF, hypoxia inducible factor 1alpha, or placental growth factor. Delineating the spatiotemporal pattern of expression of survivin after stroke, and the molecular mechanisms by which this is regulated, may provide novel approaches to therapeutically optimize angiogenesis in a variety of ischemic disorders.

Animals↗
PubMed1999

Intra-arterial papaverine for the treatment of cerebral vasospasm following aneurysmal subarachnoid hemorrhage.

BACKGROUND: Intra-arterial papaverine (IAP) has been described as a treatment for cerebral vasospasm refractory to standard therapy. METHODS: We report a series of 15 consecutive patients with aneurysmal subarachnoid hemorrhage in which IAP was employed for the treatment of symptomatic vasospasm. All patients exhibited delayed ischemic neurologic deficits, focal cerebral hypoperfusion on stable xenon-enhanced computerized tomography cerebral blood flow studies, and angiographically defined arterial narrowing. Papaverine was infused into 32 arteries on 23 occasions. Six patients required multiple treatments between 1 and 8 days apart. In five instances, IAP was combined with angioplasty. RESULTS: Angiographically defined vasospasm was at least partially reversed immediately following treatment on 18 of 23 occasions. The associated clinical improvement was major on 6 occasions, and either minor or none on 17. Post-treatment cerebral blood flow was assessed on 13 occasions and showed improvement in previously ischemic areas on six occasions and no improvement on seven. Complications were encountered on four occasions. Systemic hypotension and transient brain-stem depression were seen with vertebral artery infusions; a generalized seizure and paradoxical aggravation of vasospasm resulting in hemispheric infarction occurred with internal carotid artery infusions. CONCLUSIONS: Intra-arterial papaverine resulted in reversal of arterial narrowing in the majority of cases (78%). However, this angiographic improvement was associated with cerebral blood flow augmentation in only 46% of cases analyzed, and major clinical improvement in 26%.

Adult↗
PubMed1989

Stereotaxic suboccipital transcerebellar biopsy of pontine mass lesions.

Twenty-six patients (16 male and 10 female) ranging in age from 5 to 68 years underwent suboccipital transcerebellar stereotaxic biopsy of mass lesions situated in the pons. Stereotaxic computerized tomography, magnetic resonance imaging, and angiographic data were obtained while the patient was positioned in an inverted custom stereotaxic head frame. The patients were then placed under general endotracheal anesthesia and positioned prone. Optimal trajectory planning utilized a transcerebellar route directed through the middle cerebellar peduncle, with target and entry points calculated to avoid vascular structures. No complications were encountered in the perioperative period when this technique was used. Histological diagnosis of the lesions revealed: astrocytomas in 14 patients, oligodendroglioma in one, ependymoma in one, arteriovenous malformations in two, radionecrosis in one, cryptococcal abscess in one, demyelinating disease in three, and infarctions in three. No consistent correlation could be made between radiographic characteristics and histological diagnoses. Empiric treatment of brain-stem lesions without tissue diagnosis based upon the radiological and clinical findings may result in inappropriate therapy administration. Alternatively, open operative procedures to obtain tissue require a visible surface abnormality to guide biopsy, and carry the risks of a major surgical procedure in already compromised patients. For these reasons the authors consider a suboccipital transcerebellar stereotaxic biopsy to be the diagnostic procedure of choice in the assessment of pontine mass lesions.

Adolescent↗
PubMed1984

[Local fibrinolytic treatment in occlusions of the central retinal artery].

The effectiveness of thrombolytic agents used in local infusion has been demonstrated in the treatment of acute myocardial infarctions by several randomized trials. Thrombolytic therapy seems also to improve the prognosis of certain acute life-threatening brain stem strokes. Two cases of central retinal artery occlusion were treated with intracarotid urokinase injections. Visual acuity was improved in both cases in less than 24 hours, repermeation of the occluded vessels was observed 48 hours after the beginning of treatment. The limits of this kind of therapy are emphasized: there must be no contra-indication to the fibrinolytic agents, a delay shorter than 6 hours after the beginning of symptoms, a lack of arguments in favour of an embolism, and integrity of the carotid bifurcation. Surveillance in an intensive cares unit during the first days is required.

Adult↗
PubMed2002

Human bone marrow stem cells exhibit neural phenotypes and ameliorate neurological deficits after grafting into the ischemic brain of rats.

There is now evidence to suggest that bone marrow mesenchymal stem cells (MSCs) not only differentiate into mesodermal cells, but can also adopt the fate of endodermal and ectodermal cell types. In this study, we addressed the hypotheses that human MSCs can differentiate into neural cells when implanted in the brain and restore sensorimotor function after experimental stroke. Purified human MSCs were grafted into the cortex surrounding the area of infarction 1 week after cortical brain ischemia in rats. Two and 6 weeks after transplantation animals were assessed for sensorimotor function and then sacrificed for histological examination. Ischemic rats that received human MSCs exhibited significantly improved functional performance in limb placement test. Histological analyses revealed that transplanted human MSCs expressed markers for astrocytes (GFAP(+)), oligodendroglia (GalC(+)), and neurons (beta III(+), NF160(+), NF200(+), hNSE(+), and hNF70(+)). The morphological features of the grafted cells, however, were spherical in nature with few processes. Therefore, it is unlikely that the functional recovery observed by the ischemic rats with human MSC grafts was mediated by the integration of new "neuronal" cells into the circuitry of the host brain. The observed functional improvement might have been mediated by proteins secreted by transplanted hMSCs, which could have upregulated host brain plasticity in response to experimental stroke.

Adolescent↗
PubMed1978

[Tabular method of evaluation in the diagnosis of complicated brain infarct].

On the basis of a clinico-anatomical comparison in 70 cases of complicated infarctions and 77 observations of white infarctions the author elaborated computing tables. It was established that the following signs have certain diagnostic significance: the degree of changed consciousness, meningeal symptoms, symptoms indicating a secondary lesion of the brain stem and symptoms characterizing the degree of focal neurological disturbances. Among the supplementary methods of special significance is CSF analysis.

Aged↗
PubMed1992

[Magnetic resonance tomography in the diagnosis and differentiation of cerebral stroke].

Assessment of the MRT with an ultra-low magnetic intensity (0.04 Tesla) in 112 patients with different brain strokes has demonstrated the method to be of high information content from the standpoint of the diagnosis and differentiation of foci of injury. MRT is of special importance for detection of lacunar and mixed infarction and foci of stem localization. The use of MRT in the course of the disease permits estimation of the physicochemical and biological processes that occur in ischemia and hemorrhage together with the quality of the treatment given to the patients.

Brain↗
PubMed1997

Stroke associated with cardiac surgery. Determinants, timing, and stroke subtypes.

OBJECTIVE: To determine the nature of strokes complicating cardiac surgery. DESIGN: A medical record review was undertaken of all patients who underwent cardiac surgery (either coronary bypass, valvular surgery, or both) between January 1990 and July 1995. Univariate and multivariate analyses were done using odds ratios (ORs) and logistic regression. RESULTS: A total of 2211 patients underwent cardiac surgery. A total of 44 patients (2%) had postoperative strokes. They were compared with 104 surgical controls. Univariate analysis revealed that the patients with stroke were significantly older and had significantly higher rates of transient ischemic attack, congestive heart failure, and peripheral vascular disease by history. A multivariate logistic regression revealed the significant variables associated with stroke were congestive heart failure (OR, 6.8) and transient ischemic attack (OR, 1.2). Analyses of surgical variables revealed that bypass pump time of more than 120 minutes (OR, 1.40) was the only significant predictor. The majority of strokes (61%) had occurred by postoperative day 2, but 39% occurred between postoperative days 3 to 9. Hemispheric syndromes occurred in 70%, brain stem and cerebellar syndromes in 14%, and lacunar syndromes in 16%. Computed tomographic scans revealed that 29 patients had new infarcts, of which 20 (69%) were territorial, 5 (17%) were small deep, and 4 (14%) were border zone. Hemorrhagic infarction was found in 2 cases (5%). One patient (2.5%) had a cardiorespiratory arrest while undergoing computed tomography. Discharge disposition was good in 88% of patients with stroke (12% with poor outcomes) vs 97% of controls with good outcomes (3% with poor outcomes) (P = .04). CONCLUSIONS: Strokes may be delayed following cardiac surgery perhaps because of ongoing risk of embolism or a hypercoagulable state. A surprisingly high proportion of patients have lacunar syndromes or small-deep infarcts shown on computed tomography. Early computed tomographic imaging may be useful to exclude hemorrhage if anticoagulation is considered, but is not without risk in these potentially unstable patients. Greater understanding of risk factors for stroke, timing, and subtypes may ultimately allow identification of patients at particularly high risk for perioperative stroke.

Aged↗
PubMed1997

Acoustic neuromas: results of current surgical management.

OBJECTIVE: In this article, we review the surgical outcomes of 179 patients with acoustic neuromas. METHODS: Most of the tumors (84%) were operated on using a retrosigmoid, transmeatal approach. A transpetrosal, retrosigmoid approach was used in 10% of the patients, most of whom had large tumors. The translabyrinthine (4%) and transmastoid, transpetrosal, partial labyrinthectomy approaches (2%) were used selectively. The operative approaches are discussed. Tumors were categorized according to their cerebellopontine angle dimensions as small (< 2 cm), medium (2.0-3.9 cm), and large (> or = 4 cm). RESULTS: House-Brackmann evaluation of postoperative facial nerve function revealed excellent results (Grade I or II) in 96% of small tumors, 74% of medium tumors, and 38% of large tumors. A fair postoperative function (Grade III or IV) was achieved in 4% of small tumors, 26% of medium tumors, and 58% of large tumors. Functional hearing preservation, defined as Gardner-Robertson Class I or II, was achieved in 48% of small tumors and 25% of medium tumors. Hearing was not preserved in any of the three patients with large tumors in whom hearing preservation was attempted. Treatment complications consisted mainly of cerebrospinal fluid leakage (15% of the patients). The majority of the patients who experienced cerebrospinal fluid leakage were treated successfully with lumbar spinal drainage; only four patients (2% of the total group) required subsequent surgery for correction of cerebrospinal fluid leakage. There were two deaths (1%) in this series. One death occurred as the result of myocardial infarction and the other as the result of severe obstructive lung disease. One patient sustained disability because of cerebellar and brain stem injury. Complete tumor resection was accomplished in 99% of the patients, and there was no evidence of recurrence in this group. Only 1 of the 179 patients underwent incomplete tumor resection; he required subsequent surgery for symptomatic tumor regrowth. Our patient follow-up had a mean duration of 70 months and a median of 65 months (range, 3-171 mo). CONCLUSION: Our results are similar to those of other large microsurgical series of acoustic neuromas. Unless a patient has major medical problems, microsurgery by an experienced team of surgeons is preferred over radiosurgery.

Adolescent↗
PubMed1993

Stroke subtypes among Hispanics living in Guayaquil, Ecuador. Results from the Luis Vernaza Hospital Stroke Registry.

BACKGROUND AND PURPOSE: Racial differences in stroke subtypes have been documented. Asians have a higher rate of cerebral hemorrhage than whites; however, there is little information about stroke subtypes among Hispanics. The purpose of this study was to determine the patterns of stroke subtypes in a population of Hispanics. METHODS: Five hundred consecutive patients with a first stroke were included. Patients were collected from hospital wards, the emergency department, and the outpatient clinic to ensure inclusion of patients with a wide range of stroke severity. Computed tomography was available in all cases. Patients with pure subarachnoid hemorrhage were excluded. RESULTS: There were 313 (62.6%) patients with an infarct and 187 (37.4%) with a hemorrhage. Hypertensive arteriolopathy was the most common cause of both infarcts and hemorrhages. The carotid territory was involved in 70.6% of the 313 patients with infarcts, the vertebrobasilar territory in 17.9%, multiple territories in 6.7%, and a watershed area in 4.8%. Hemorrhages were most often lobar (36.4%), followed by putaminal (30.5%), brain stem (9.1%), cerebellar (8%), thalamic (8%), ventricular (5.3%), and caudate (2.7%). CONCLUSIONS: This hospital-based stroke registry suggests that stroke in Hispanics has a pattern different from that in whites but similar to that in Asians. Cerebral hemorrhages occur three times more frequently in Hispanics than in whites.

Adult↗
PubMedDate not supplied

Brain damage in non-missile head injury secondary to high intracranial pressure.

A comprehensive neuropathological analysis was undertaken on 434 patients who died as a result of a non-missile head injury in order to determine the frequency and extent of brain damage secondary to high intracranial pressure (ICP) in head injury. Using the criterion of pressure necrosis in the parahippocampal gyrus as evidence of high ICP due to a supratentorial expanding lesion, it was established that the ICP had been high in 324 cases. In 42 of these there was no other brain damage attributable to a high ICP. There was evidence of secondary brain stem damage in 221 cases and in 44 of these the damage could be seen only microscopically. In 54 cases there was a contralateral peduncular lesion. Other abnormalities were infarction in the territories of various arteries and in the anterior lobe of the pituitary. There was a supracallosal hernia in 80 cases and haemorrhage in the oculomotor nerves in 48 cases. These results further emphasise the frequency and range of brain damage due to secondary vascular factors brought about by high ICP in a patient who has sustained a head injury.

Adolescent↗