ISSN:1350-7540    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Childhood stroke is emerging as a serious and frequent disorder. In contrast to adult stroke, the study of childhood stroke is in a very early stage of research development with no randomized controlled trials conducted to date outside of sickle cell stroke. The results of research in adults have limited applicability to children with stroke due to fundamental age-related differences in the neurological, cerebrovascular and coagulation systems. In recent years clinical and basic research studies have improved our understanding of childhood stroke. Population-based studies have resulted in an increased awareness of the frequencies and features of stroke syndromes in children. Cohort and case-control studies have led to an enhanced understanding of the multiple risk factors underlying childhood stroke. Advances in neuroimaging and in genetic and other laboratory testing approaches have resulted in an increased definition of stroke subtypes and risk factors.

ISSN:1350-7540    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The role of plasma-phase risk factors for stroke in the pediatric age group is presently unclear due to the lack of sufficiently large prospective studies, and due to the fact that these risk factors do not apply uniformly to newborns, children with sickle cell disease, and older children. Available evidence indicates that factor V Leiden, prothrombin 20210A, and lipoprotein (a) are all important in the pathogenesis of arterial ischemic stroke in older children, but the role of other plasma-phase risk factors remains uncertain. The contribution of these risk factors to newborn stroke and the stroke of children with sickle cell disease is similarly unclear, likely because the ischemia in affected children is predominantly due to nonhematologic perinatal events and erythrocyte adhesion to endothelium with obstruction of flow in the cerebral microcirculation, respectively. Evaluation of childhood stroke should, in our view, always be performed from the standpoint of the presenting clinical symptoms, diagnostic imaging, and determination of plasma-phase risk factors. Therapeutic anticoagulation and use of antiplatelet agents at present focus on the older child.

ISSN:1350-7540    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

There is an expanding understanding of primary genetic oxidative-phosphorylation disorders and the recognition of new multi-system clinical phenotypes in the energy metabolism diseases. Although initially recognized in association with mitochondrial DNA mutations, there is progress in the more laborious identification of nuclear DNA encoded genes relevant to mitochondrial structure and function. More pathogenic mitochondrial DNA and nuclear DNA mutations have been identified. Diagnosis of these disorders is often difficult and relies on a concurrence of findings, including recognition of a variety of clinical signs and symptoms, biochemical marker screening, electron transport chain enzyme measurements, and mitochondrial DNA or nuclear DNA mutation assay of genes relevant to mitochondrial structure, function or adenosine triphosphate metabolic pathways. Clinical diagnostic assessment now can be augmented by physiologic imaging techniques, including nuclear magnetic resonance spectroscopy and positron emission tomography. These capabilities should be increasingly helpful for studies of clinical progression and therapeutic intervention. Biologic studies, in families and patients, are beginning to address the factors of mitochondrial replication and segregation that underlie cellular/tissue heteroplasmy and clinical variability. Most epigenetic factors affecting organ-specific and phenotypic variability, however, remain to be elaborated.

ISSN:1350-7540    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Major advances in understanding the cellular mechanisms of brain injury have presented a host of potential targets for intervention. This is particularly true of hypoxic-ischemic injury, the most important form of perinatal brain injury. As the window for effective clinical intervention may be particularly narrow in the fetus and newborn because of the often-delayed and subtle presentation of the onset of the insult, recent focus has been on defining and countering the more delayed mechanisms of brain injury. Recent insights into the mechanisms of oligodendrocyte injury and the role of inflammatory substances in perinatal brain injury are also discussed.

ISSN:1350-7540    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The role of infectious and inflammatory causes of stroke is much more significant in children than in adults. Conversely, that of atherosclerotic disease, ischaemic heart disease and hypertensive haemorrhages has a lesser prominence in children. Bacterial meningitis caused byStreptococcus pneumoniae,Haemophilus influenzae, orNeiserria meningitidishas been known to cause stroke in children. The mechanism appears to be the spread of meningeal inflammation to involve the walls of intracranial vessels, resulting in arterial thrombosis with ischaemia or rupture with haemorrhage. Other infections caused by atypical bacterial agents such asMycoplasma tuberculosisand viral agents such as varicella-zoster virus have also been well documented as causes of stroke. Non-infectious, inflammatory causes of stroke, such as collagen vascular disease and primary angiitis of the central nervous system, have been reported in children as well as adults. In this review, we will focus on recent advances in the field of childhood stroke caused by infectious and inflammatory disorders.

ISSN:1350-7540    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The population of pediatric patients with cerebrovascular disease presents a unique set of challenges to the neurosurgeon. The wide scope of pathology, including arteriovenous malformations, cavernous malformations and moyamoya disease, coupled with marked advances in diagnosis and treatment of these conditions over the past several years has resulted in a proliferation of the literature related to this subject. The present review provides an overview of current methods of surgical treatment for pediatric cerebrovascular diseases, focusing on indications and use of recent refinements of pre-existing surgical approaches, and newly evolved operative techniques developed to treat these entities.

ISSN:1350-7540    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Beginning in the 1970s engineers designed systems to predict epileptic seizures based upon quantitative changes in the electroencephalogram, which they hypothesized began well in advance of clinical seizure onset. These efforts flourished in the 1990s, as independent laboratories demonstrated evidence of a ‘preseizure period’ up to 20 min prior to clinical symptoms in patients implanted with intracranial electrodes during evaluation for epilepsy surgery. Years later, clinical and laboratory experiments leave little doubt that a preseizure period exists in temporal lobe and perhaps other forms of epilepsy. Its existence, however, raises fundamental questions about what constitutes a seizure, what brain regions are involved in seizure generation, and whether discrete interictal, preictal, ictal and post-ictal physiologies exist, or blend together in a continuous process. Pressing milestones, necessary for clinical utility, are: (1) demonstrating prospective seizure prediction from prolonged human data sets, (2) elucidating mechanisms underlying seizure precursors and (3) implementing these algorithms on implantable hardware platforms. The notion of a preseizure state is catalyzing new clinical and basic science research, which has the potential to dramatically increase our understanding of epilepsy, and to generate exciting new therapies for patients.

ISSN:1350-7540    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Mitochondrial dysfunction has gained considerable interest as a potential cause of epileptic seizures and therapy-resistant forms of severe epilepsy. Impairment of mitochondrial function has recently been observed in the seizure focus of human and experimental epilepsy. Additionally, a broad variety of mutation of mitochondrial DNA leading to the inhibition of mitochondrial respiratory chain or directly of mitochondrial adenosine triphosphate synthesis in epileptogenic areas of the human brain has been associated with epileptic phenotypes. Since mitochondrial oxidative phosphorylation provides the major source of adenosine triphosphate in neurons and mitochondria participate in cellular Ca2+homeostasis they can modulate neuronal excitability and synaptic transmission. Furthermore, mitochondria are intimately involved in pathways leading to the neuronal cell death characteristic for the areas of epileptogenesis.

ISSN:1350-7540    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

In patients with pharmacologically intractable, complex-partial seizures, surgical excision of the involved temporal lobe may have significant therapeutic benefit. Resection of mesial structures of the temporal lobes, however, entails a significant risk of decreased memory function. Recent advances in the assessment of memory changes following temporal lobectomy surgery emphasize the complexity of subjective ratings of memory functioning in this population. Neuroimaging tools useful in the diagnostic evaluation of epilepsy surgical candidates have now been shown to be useful in predicting memory change in the post-surgical period. Functional magnetic resonance imaging appears to provide significant information regarding hemispheric representation of language in the temporal lobe epilepsy patient, and the use of this technique to predict memory status following surgery appears promising. Clinical studies involving patients who had temporal lobectomy surgeries have also revealed changes in emotional learning related to the degree of amygdala involvement. Moreover, there is increasing evidence to suggest that differential changes in emotional learning occur among patients with right versus left temporal lobe resections.

ISSN:1350-7540    

出版商:OVID    

年代:2002

数据来源: OVID