摘要:

MAJOR ADVANCES IN cell culture techniques, immunology, and molecular biology during the last 10 years have led to significant progress in understanding the process of normal glial differentiation. This article summarizes our current understanding of the cellular and molecular basis of glial differentiation based on data obtained in cell culture and reviews current hypotheses regarding the transcriptional control of the gene switching that controls differentiation. Understanding normal glial differentiation has potentially far-reaching implications for developing new forms of treatment for patients with glial neoplasms. If oncogenesis truly involves a blockage or a short circuiting of the differentiation process in adult glial progenitor cells, or if it results from dedifferentiation of previously mature cells, then a clear understanding of differentiation may provide a key to understanding and potentially curtailing malignancy. Differentiation agents represent a relatively new class of drugs that effect cellular gene transcription at the nuclear level, probably through alterations in chromatin configuration and/or differential gene induction. These exciting new agents may provide a means of preventing the dedifferentiation of low-grade gliomas or inducing malignant glioma cells to differentiate with minimal toxicity. In the future, genetic therapy has the potential of more specifically rectifying the defect in genetic control that led to oncogenesis in any given tumor.

ISSN:0148-396X    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

LONG-TERM EVALUATION OF patients with aneurysms of the internal carotid artery (ICA) treated by intravascular balloon occlusion has not been reported. From 1977 to 1992, 58 patients (age 14 to 81 years) with ICA aneurysms were treated at our institution by this technique. The aneurysms included 40 intracavernous carotid, 5 petrous carotid, 3 cervical carotid, and 10 ophthalmic segment aneurysms. Presenting symptoms were caused by mass effect in 45 patients, transient ischemia or cerebral infarction as a result of emboli in 6, subarachnoid hemorrhage in 4, and epistaxis in 3. Preoperative temporary balloon occlusion of the ICA combined with cerebral blood flow monitoring and induced hypotension were used to determine tolerance for occlusion. Two patients not tolerating test occlusion required an extracranial-intracranial bypass procedure, and another patient underwent extracranial-intracranial bypass prior to test occlusion because of contralateral ICA stenosis. In 55 patients, aneurysms were excluded from the circulation by either occluding the proximal ICA or trapping the aneurysm neck. In three patients, the aneurysm was directly obliterated with intravascular balloons with preservation of the parent ICA. Three patients died during treatment, one from subarachnoid hemorrhage and two from cerebral infarction. Mean follow-up was 76 months (range, 6 months to 15 years). Six patients who developed transient ischemia caused by emboli responded to volume expansion and anticoagulation treatment. Two patients developed a delayed infarction, and one patient developed aneurysm enlargement that required surgical clipping and obliteration. Two patients suffered a delayed subarachnoid hemorrhage, one from a de novo aneurysm arising from the anterior communicating artery and another from a contralateral A1-A2 junction aneurysm that had enlarged after treatment for the ICA aneurysm. In long-term follow-up, intravascular balloon occlusion was a relatively safe, effective treatment for eliminating ICA aneurysms that posed low risk for early or delayed ischemia or infarction. Intravascular balloon occlusion is the treatment of choice for extradural aneurysms and some distal carotid aneurysms.

ISSN:0148-396X    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

THE MANAGEMENT OUTCOME of 302 patients with multiple intracranial aneurysms (MIA) from a series of 1314 patients with cerebral aneurysms was assessed using the Glasgow Outcome Scale 1 year after diagnosis and/or treatment. The outcome was significantly poorer for patients with MIA than for those with single intracranial aneurysms (SIA). The difference in the frequencies of poor outcome (Glasgow Outcome Scale Grades 3–5) was most evident in patients with Hunt and Hess Grades 2 or 3 (MIA, 29%; SIA, 19%). The management mortality in all grades attributable to all causes was 24% in patients with MIA and 20% in those with SIA and 16 and 11%, respectively, after surgery. At the 1-year follow-up point, 66% of the patients with MIA were independent (SIA, 72%); after surgery, 74% (SIA, 81%); after subarachnoid hemorrhage, 65% (SIA, 71%); and after subarachnoid hemorrhage and surgery, 73% (SIA, 80%). Patients with aneurysms at the vertebrobasilar arteries fared badly; otherwise, the sites of the aneurysms and their different combinations had no effect on outcome, nor did the timing of surgery. In this study, again, only two-thirds of the detected aneurysms could be secured. The aneurysms left without treatment were mostly in patients with very poor grade (n, 55) and/or old (n, 23) patients or were intracavernous (n, 26). The results seemed to be more unsatisfactory as the number of aneurysms increased. In multivariate analysis, delayed neurological deficit had the most significant independent contribution to outcome in patients with MIA, far more than in patients with SIA. This can be explained by the increased manipulation of cerebral arteries during multiple aneurysm surgery.

ISSN:0148-396X    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

MEMORY DECLINE REPRESENTS the primary neuropsychological morbidity of anterior temporal lobectomy. Recent investigations using laboratory tests of memory have reported an association between the neuropathological status of the resected left mesial temporal region and memory outcome, with adverse memory outcome associated with a lack of significant left hippocampal pathology. The purpose of this investigation was to examine the relationship between the reports by the patients and their families of observed postoperative changes in day-to-day memory function and the degree of hippocampal sclerosis in resected left mesial temporal lobes. Twenty patients and a close family member (parent or spouse) of each of the patients completed standardized questionnaires assessing pre- to postoperative changes in verbal and spatial memory; these were related to the neuropathological findings. The results indicated that patients without left hippocampal sclerosis reported significantly worse memory outcome than those with hippocampal sclerosis. The ratings provided by the relatives of the patients yielded a comparable effect, and objective memory tests supported the reports by the patients and their families. The neuropsychological findings associated with left hippocampal pathology are of clinical significance and should be considered in surgical evaluation and in the counseling process.

ISSN:0148-396X    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

WE REPORT OUR experience with and long-term results of 37 patients with tentorial meningiomas who underwent surgery between 1972 and 1993. The average age was 43 years, and the mean duration of symptoms was 36 months. Headache (83.8%) and extremity or gait ataxia (35.1%) were the most common complaints. On neurological examination, signs of elevated intracranial pressure and cerebellar deficits (51.4%) were the most common findings, followed by third nerve involvement (35.1%). Computed tomography, angiography, and, in recent years, magnetic resonance imaging were used as diagnostic tools and for planning the surgical procedure. According to the primary site of attachment, the tentorial meningiomas were divided into three subgroups: medial, lateral, and falcotentorial. The lateral and medial tumors, with mainly supratentorial development, were approached from above by using a temporal, temporooccipital, or parietooccipital craniotomy. For tumors developing mainly in the posterior cranial fossa, suboccipital craniectomy was performed. In six patients who showed medial tentorial and petrous apex attachment, a combined subtemporal transpetrosal and retromastoid approach was performed. In 31 patients, the tumors were totally removed, and, in 6 patients, only subtotal excision could be done. Seven patients had postoperative complications, but only one of them died of severe brain edema. Our mortality rate was 2.7%. In this article, appropriate preoperative studies, surgical techniques, and surgical results are discussed.

ISSN:0148-396X    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

WE REPORT ON our recent experience with epidermoid cysts in the cerebellopontine angle. We operated on nine patients since 1985, seven of which were investigated with magnetic resonance imaging. Since the arrival of modern neuroimaging, large lesions can be found with only discrete symptoms, such as isolated tinnitus or unspecific headache. With computed tomography and magnetic resonance imaging, preoperative diagnosis was achieved for most patients; sometimes, however, epidermoid cysts may be very similar to arachnoid cysts. Surgery is the only possible treatment. The decision to operate should be carefully discussed for each patient, particularly if the patient is asymptomatic. The extent of the lesion at the anterior aspect of the brain stem, and sometimes above the tentorium cerebelli, fragile cortex, and vessels, and hazards of postoperative chemical meningitis often make such surgery difficult. The surgeon should not attempt total removal of the cyst membrane. Most patients who undergo surgery, however, recover well, with no or few sequelae. With a mean 3-year follow-up, no recurrence occurred, despite partial removal, as a result of the peculiarly slow growth of these lesions.

ISSN:0148-396X    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

GLOSSOPHARYNGEAL NEURALGIA IS an uncommon craniofacial pain syndrome that is occasionally associated with cardiac syncope. Involvement of the glossopharyngeal nerve may be painless or may be marked by true episodic neuralgia, and this justifies the termneuralgiareported here. We present 5 cases of this uncommon syndrome, of a total of 15 observed cases of glossopharyngeal neuralgia, successfully treated by section of the rootlets of Cranial Nerves IX and X or by microvascular decompression in the posterior cranial fossa. We also analyze the relevant literature and discuss the pathogenesis and treatment of the syndrome.

ISSN:0148-396X    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

GLOSSOPHARYNGEAL NEURALGIA IS an uncommon cause of facial pain with a relative frequency of 0.2 to 1.3% when compared with trigeminal neuralgia. It is characterized by intermittent, lancinating pain involving the posterior tongue and pharynx, often with radiation to deep ear structures. Since its first description in 1910 by Weisenburg, a variety of destructive procedures have been performed to provide relief in patients whose pain was refractory to medical treatment. These procedures all necessitated the sacrifice of the glossopharyngeal nerve and, in most cases, also involved the destruction of at least part of the vagus nerve as well. In 1977, Laha and Jannetta reported good results in four patients who underwent microvascular decompression of the glossopharyngeal and vagus nerves for glossopharyngeal neuralgia. Since 1971, 40 patients have undergone microvascular decompression of the glossopharyngeal and vagus nerves for treatment of typical glossopharyngeal neuralgia. This procedure provided excellent immediate results (complete or >95% relief of pain) in 79%, with an additional 10% having a substantial (>50%) reduction in pain. Long-term follow-up (mean, 48 mo; range, 6–170 mo) reveals excellent results (complete or >95% reduction in pain without any medication) in 76% of the patients and substantial improvement in an additional 16%. There were two deaths at surgery (5%), both occurring early in the series as the result of hemodynamic lability causing intracranial hemorrhage. Three patients (8%) suffered permanent 9th nerve palsy. These results demonstrate that microvascular decompression of the glossopharyngeal and vagus nerves is an effective treatment for glossopharyngeal neuralgia and can be performed safely in centers experienced in the neuroanesthetic treatment of posterior fossa surgery.

ISSN:0148-396X    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

SLEEP APNEA IS a rare complicating factor of acromegaly associated with a high risk of perioperative airway compromise and unclear response to transsphenoidal resection of the underlying pituitary tumor. We reviewed four acromegalic patients with sleep apnea and documented postoperative objective and subjective improvement of their sleep disorders. The pathogenesis of this disorder and safe perioperative airway management are discussed.

ISSN:0148-396X    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

BACTERIAL BRAIN ABSCESSES occur in approximately 1500 to 2500 patients each year in the United States. Multiple abscesses have been noted in 10 to 50% of these patients. The goal of this study was to better define the roles of surgery and medical management in patients harboring multiple brain abscesses and to develop an algorithmic approach to the treatment of these complex patients. Between 1976 and 1992, 16 patients with multiple brain abscesses were treated by a single physician (M.L.R.). The ages of the patients ranged from 1.5 to 73 years (median, 47 yr). In all patients, a diagnosis of multiple abscesses was made by computed tomography (15 patients) or magnetic resonance imaging (1 patient) brain scans. The number of abscesses per patient ranged from 2 to 30, and the abscesses were located in all regions of the brain. Thirteen received a combination of antibiotics and surgical drainage, and three received antibiotics only. Surgery was performed on abscesses larger than 2.5 cm or on those situated in critical areas of the brain or causing significant mass effect. Excision and open aspiration via craniotomy and stereotactic aspiration were analyzed on the basis of the location of the lesion and infecting organism. Any abscess that enlarged after 2 weeks of antibiotics or that failed to shrink after 3 to 4 weeks of antibiotics was again aspirated or excised. Forty-three surgical procedures were performed in 13 patients, and 8 (62%) of the patients operated on required more than one surgical procedure. No significant morbidity was observed in any of the surgical procedures. Antibiotics were administered intravenously for an average of 6 to 8 weeks and were adjusted according to organism type and sensitivity to antibiotics. One patient (6%) died, and the remaining 15 patients had resolution of all abscesses and good neurological recovery within 6 months. On the basis of these results, we propose a combined surgical and medical approach to the treatment of patients with multiple brain abscesses. We recommend the aggressive surgical drainage of all abscesses larger than 2.5 cm in diameter, combined with 6 to 8 weeks of intravenous antibiotics. Biweekly computed tomography or magnetic resonance imaging is necessary to closely monitor patients for evidence of abscess growth or failure to resolve despite antibiotics, prompting another operation. The application of this combined approach should yield cure rates of more than 90% in patients with multiple brain abscesses, a result similar to that expected when treating patients with solitary lesions.

ISSN:0148-396X    

出版商:OVID    

年代:1995

数据来源: OVID