摘要:

Purpose of reviewMagnetic resonance imaging (MRI) of brain tumours provides excellent anatomical detail of brain tumours and can also reveal the biology, cellular structure and vascular dynamics of a tumour, although the use of such features in routine clinical practice has yet to be realized. In this review the latest advances in MRI of brain tumours are discussed and their clinical applications highlighted.Recent findingsA large international study is underway to develop more powerful methods for automated classification of MR spectra based on the acquisition of large datasets of tumour spectra. Diffusion weighted imaging can help in the distinction between gliomas and abscesses, and perfusion weighted imaging can predict response to radiotherapy in low grade gliomas as well as distinguishing between different types of cerebral metastases. Intraoperative MRI has now been shown to be technically feasible, safe and effective in obtaining histological information as well as increasing the likelihood of complete resection for pituitary tumours and gliomas. Functional MRI and magnetic source imaging are alternative modalities that help the surgeon to avoid eloquent brain areas but may occasionally provide misleading information. Diffusion tensor imaging can demonstrate the effect of a tumour on white matter tracts and provides complementary information to that from other techniques that reveal areas of eloquent cortex.SummaryAdvances in MRI techniques are providing better diagnostic and therapeutic information, but can only ever be a surrogate marker of physiological and pathological processes; until it can routinely be used to image the brain at a cellular level, MRI will always be secondary to pathology in the final diagnostic evaluation.

ISSN:1350-7540    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewThis review examines the emerging role of agents that target tumour blood vessels in the treatment of glioma. It addresses the important issue of how these agents may best be combined with conventional radiation based therapies to optimize their effects, and reviews recent experimental and clinical data on which future treatment policies may be developed.Recent findingsTwo main classes of agents can be used to influence tumour growth through their actions on the vasculature. Antiangiogenic agents prevent the formation of new tumour blood vessels, whereas vascular targeting agents destroy existing tumour blood vessels. Based on an improved understanding of the biology of tumour vasculature, many new agents are being developed that exhibit these effects in preclinical models. Several agents are also entering clinical trials. At the same time, new evidence is emerging that the effect of conventional therapies, particularly radiotherapy, may exert important antitumour effects through actions on the vasculature as well as through cytotoxic effects on tumour clonogens. Preclinical data suggest that the combination of these agents may not act in a straightforward synergistic manner, suggesting that careful consideration of scheduling will be required to optimize their effects.SummaryAgents that act at the tumour vasculature provide a powerful new potential strategy in tumour treatment. However, these agents will need to be used in combination with conventional treatment strategies, and optimal combinations need to be defined in preclinical studies. This will depend on gaining a more thorough understanding of the effects of other modalities on tumour vasculature.

ISSN:1350-7540    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewOptic tract low-grade gliomas are one of the commonest category of neoplasm presenting in childhood and early adolesence. Recent reports covering their aetiology, imaging techniques, the application of novel radiotherapy techniques and chemotherapy are reported.Recent findingsThese tumours are increasingly being seen as markers of enhanced risk in patients and their families for the subsequent development of central nervous system tumours. Modern imaging techniques are being explored for their diagnostic sensitivity and specificity as well as their ability to describe, with greater precision, anatomical boundaries in order to minimize, through conformal techniques, radiation doses to organs at risk within the brain. Increasing numbers of trials of chemotherapy agents are demonstrating efficacy in this tumour category.SummaryVisual pathway low-grade astrocytomas of childhood are the subject of diverse research into diagnostic aetiological and treatment aspects aimed at tailoring diagnostic and treatment procedures more precisely to the needs of the young patient for this tumour type.

ISSN:1350-7540    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewTreatments for malignant glioma, the most lethal and common primary brain tumor, are undergoing a dramatic evolution led by biological and technological advancements. This review focuses on developments in novel areas of gene therapy and immunotherapy, particularly vaccine development.Recent findingsAdvances in basic research of antigen-presenting cells and applications of cytokines and immunogenic antigens have contributed to recent vaccine development for the treatment of intracranial malignant glioma. We have reviewed various vaccine designs, such as utilization of tumor antigen-loaded dendritic cells. Many immunotherapeutic manipulations require the use of recombinant genetic technologies. Here we present the findings on improved techniques for suicide gene therapy and various oncolytic viral therapies. Some of these constructs have induced an immune response at tumor sites in animal models of glioma.SummaryThe intense investigation of therapies for glioma has made significant advances in designing diverse therapies with great potential. However, vaccine development has been hampered by the lack of universal tumor-specific antigens and a limited understanding of the mechanisms of tumor-induced immunosuppression. The success of gene therapy is limited by ineffective delivery systems and possible risk of infecting normal cells. As a result of the genetic heterogeneity of glioma cells and their invasive nature, future treatment approaches are likely to combine different agents in synergistic strategies that will hopefully be successful in stopping the growth and recurrence of glioma.

ISSN:1350-7540    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewPrimary central nervous system lymphoma (PCNSL) is an aggressive B cell lymphoma that occurs in immunocompetent and immunosuppressed patients. Primary ocular lymphoma represents an important variant of this disease. The outcome for patients with PCNSL is rapidly improving with new treatment strategies. This review focuses on recent advances, investigations, and controversies in the management of these increasingly important malignancies.Recent findingsThe incidence of PCNSL is rising in immunocompetent patients over the age of 60 years for unexplained reasons. However, the incidence of AIDS-related PCNSL, which is related to Epstein-Barr virus infections, has fallen with the institution of highly active antiretroviral therapy. During the past decade, standard therapy has evolved from cranial irradiation to high dose methotrexate-based regimens. This shift in therapy has been associated with an increase in the median survival of patients from 1 year to longer than 3 years, and with an equally striking reduction in neurotoxicity if whole brain radiation is avoided. Optimal therapeutic results require careful attention to opportunistic infections, thromboembolic disease, and renal toxicities associated with high dose methotrexate.SummaryOverall, PCNSLs are increasing in frequency and the results of therapy for this disease have dramatically improved during the past decade. Many important therapeutic questions remain unanswered. These include the optimal dose, frequency, and duration of methotrexate, as well as the roles of additional systemic chemotherapy drugs, intrathecal therapy, and cranial irradiation. Further progress in this uncommon disease will depend on entering patients into carefully designed multicenter clinical trials to build upon the significant advances that have been made.

ISSN:1350-7540    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewAs the treatment of childhood brain tumours has improved, long-term survival has become more common. Cognitive, physical and psychological complications of the tumour and its treatment have been recognized more frequently in long-term survivors. This review highlights new studies on the cognitive and endocrine complications in survivors. Less-common late effects of treatment are also discussed.Recent findingsCognitive abnormalities and endocrine dysfunction are the most common complications in long-term survivors. Radiotherapy is the main cause of cognitive dysfunction, but intrathecal methotrexate and surgery are contributory factors. New studies have provided information on the frequency of endocrine complications and risk factors for the development of endocrine disorders. Endocrine complications are uncommon when the tumour has been treated with surgery alone. The risk of developing endocrine dysfunction is increased by radiotherapy, and some studies suggest that chemotherapy has an additional deleterious effect. Primary hypothyroidism may be caused by scattered irradiation from spinal and cranial radiotherapy. Direct involvement of the hypothalamus by the tumour, and hypothalamic damage secondary to surgery or radiotherapy, may cause obesity. Hypothalamic tumours also may be associated with hypersomnolence and other features consistent with narcolepsy. The pathogenesis of hypersomnolence in these patients has not been resolved. Long-term childhood brain-tumour survivors are 40 times more likely to develop a stroke than sibling controls. Superficial siderosis of the central nervous system can develop many years after curative treatment of a cerebellar tumour, but effective treatment for this disorder is not yet available.SummaryAn attempt to understand the factors that contribute to the long-term morbidity of childhood brain tumours can lead to changes in treatment that improve the quality of life in survivors. Prevention, early recognition and treatment of these complications are attainable goals.

ISSN:1350-7540    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Peripheral and cortical magnetic and electrical stimulation may find a therapeutic niche as augmentative rehabilitation interventions for lessening impairments and disabilities after brain and spinal cord injury. The momentum for these approaches arose from recent physiological studies that examined the effects of paradigms of stimulation on synaptic and biological adaptations within the cortex and lumbar cord. A case report about improvements made by Christopher Reeve is driving requests by patients with profound spinal cord injury for interventions that include resistance pedaling facilitated by electrical neuromuscular stimulation. Although the evidence for this particular approach is less than convincing, reorganization-inducing cortical and peripheral afferent stimulation protocols offer insights into the steps needed for scientific designs of these potential rehabilitation interventions.

ISSN:1350-7540    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewComputational frameworks, notably internal models and optimal control theory, have led to rapid advances in our understanding of how the brain plans and controls movement. The purpose of this review is to provide an overview of these theoretical ideas, how they have been used to interpret motor control, as well as their potential role for interpreting motor dysfunction.Recent findingsThere are two general types of internal models, neural processes that mimic the mechanical properties of the limb (and environment). Forward internal models parallel the normal causal flow of the motor periphery and estimate limb motion from motor commands. Inverse internal models perform the reverse process by estimating motor commands from signals related to intended limb motion and/or spatial targets. This framework has led to several important behavioural observations on motor planning, control and learning, and has also been influential for interpreting neural activity in awake, behaving non-human primates. A more recent framework for interpreting motor function is optimal control theory, which recognizes that noise or errors are an inherent feature of the motor system and may influence strategies to plan and control movement.SummaryInternal models and optimal feedback control both provide frameworks for interpreting motor performance, and may be of value for interpreting many motor dysfunctions associated with neurological injuries. Advanced technologies such as robots that have played a key role in these frameworks may be also of considerable value for motor assessment and rehabilitation.

ISSN:1350-7540    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewLarge-scale gene expression profiling has recently been performed on stroke and spinal cord injuries. These studies provide insights into coordinated patterns of gene expression within the injury and the interrelationships of neurodegenerative and neural repair processes after injury.Recent findingsThe molecular signals for post-stroke angiogenesis begin within hours of initial cerebral ischemia, with sequential increases in message for initially destabilizing combinations of vascular growth factors and growth factor receptors, followed by growth factor combinations that promote endothelial cell division and stabilization. The overlap in molecular signaling between post-stroke angiogenesis, neurogenesis and axonal sprouting suggests a continuum of vascular and neural reorganization in the tissue adjacent to stroke. Inflammation after injury extends through early and late changes in the cytokine message. SOCS-3, a negative regulator of cytokine signaling, is increased after injury and may be neuroprotective. Components of an adult neuronal growth program have been identified in the peripheral nervous system during axonal regeneration, with overlap to axonal sprouting after stroke. The gene expression profile of the aged brain suggests an altered central nervous system environment that may exacerbate initial injury and impair neural reorganization after stroke and spinal cord injury.SummaryWhen rigorously tested and independently validated, data from large-scale gene expression analyses provide new insights into the aggregate genetic control of stroke and spinal cord injury, and the interrelationship of important cellular events within the damaged region. These data also highlight novel genes in these processes, and suggest new directions in the investigation of tissue reorganization and repair after central nervous system injury.

ISSN:1350-7540    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewThe successful motor rehabilitation of stroke, traumatic brain-injured and spinal cord-injured patients requires an intensive and task-specific therapy approach. Budget constraints limit a hand-to-hand therapy approach, so that intelligent machines may offer a solution to promote motor recovery and obtain a better understanding of motor control. This new field of automated or robot-assisted motor rehabilitation has emerged since the 1990s.Recent findingsThis article will present clinically viable devices for upper and lower extremity rehabilitation. The MIT-Manus and the Mirror-Image Motion Enabler robot, which enable unrestricted unilateral or bilateral shoulder and elbow movement, consistently proved superior on the motor impairment level. The ARM guide, which assisted reaching in a straight-line trajectory, and the Bi-Manu-Track, which enabled the bilateral practice of a forearm and wrist movement, are currently being tested. For gait rehabilitation after stroke, the electromechanical gait trainer, GT I, has proved effective compared with treadmill training with body weight support. The Lokomat, consisting of a treadmill and a powered exoskeleton, lessened the therapeutic effort compared with manually assisted treadmill training in spinal cord-injured patients. Future developments will see more degrees of freedom, improved man-machine interaction and the implementation of virtual reality.SummaryTechnical possibilities are one aspect, but multi-centre trials and a consideration of the unsubstantiated fears among therapists of being replaced by machines will decide on the successful implementation of this most promising field to the benefit of patients.

ISSN:1350-7540    

出版商:OVID    

年代:2003

数据来源: OVID