Diffuse brain stem gliomas Are we improving outcome?

We reviewed our experience with diffuse brain stem glioma (dBSG) to evaluate whether any improvement of outcome had occurred in our patients over the years. Of the 24 children referred to our department with suspected dBSG from 1981 to 1997, 5 had a different final diagnosis based on the clinical course. Mean survival in the remainder was 16±9.8 months from diagnosis. Survival increased with a longer interval from onset of symptoms to diagnosis (12.9±9.0 months with an interval of 1–4 weeks; 19.50±10.8 months with a longer interval). Visual symptoms at presentation were associated with a poorer prognosis. Survival was better in the 3- to 5-year age group (at diagnosis). Overall, a trend toward a slight improvement in survival was seen over the years, which we presumptively attribute to the introduction of intensive chemotherapy for these patients. We suggest that chemotherapy may be important in the management of dBSG until a better modality is found. Received: 10 May 1998     

脑干胶质瘤磁共振波谱分析

目的探讨磁共振波谱(Magnetic resonance spectroscopy,MRS)在脑干胶质瘤诊断中的意义。方法回顾性分析10例脑干胶质瘤的临床资料,肿瘤位于中脑1例,中脑脑桥1例,脑桥7例,延髓1例。均行MRS检查,对肿瘤区、肿瘤边缘区和正常对照区进行对照研究。结果MRS均显示肿瘤区N-乙酰天门冬氨酸(N-acetylaspartate,NAA)峰值下降,胆碱(Choline,Cho)峰上升。与肿瘤边缘区和正常对照区比较,肿瘤区NAA/Cr明显减低,Cho/Cr和Cho/NAA明显升高。星形细胞瘤4例,间变性星形细胞瘤1例,胶质母细胞瘤2例;另3例根据临床特点和影像学表现诊断为脑干胶质瘤。结论MRS可检测到脑干胶质瘤的代谢改变,具有无创、敏感、诊断准确的特点。     

Chemotherapy for brain stem gliomas

Approximately 80% of tumors arising in the brain stem are diffuse intrinsic lesions. Patients typically present with a short duration of symptoms and signs with significant neurological impairment. Imaging findings are typical, and biopsy is not usually necessary to make a diagnosis. Standard treatment consists of radiotherapy alone. Although the majority of patients will show a significant improvement in neurological status following such treatment, the prognosis is very poor. The median time to disease progression is of the order of 5–6 months, the median survival time less than 1 year, and survival at 2 years and beyond, less than 10%. Over the last 10–15 years, numerous studies have been undertaken in an attempt to develop more effective treatment for children with diffuse intrinsic brain stem tumors. Using a hyperfractionated (twice-daily) schedule, doses of radiotherapy as high as 78 Gy have been given without success. Other approaches use chemotherapy combined with radiotherapy in a variety of different ways, including up-front, concurrent, and adjuvant chemotherapy, and high-dose chemotherapy with rescue. The results of these studies using chemotherapy, as well as other approaches using other systemic agents, are reviewed in detail. Received: 12 April 1999     

Permanent I-125 brain stem implants in children

Between 1988 and 1997, 28 children have had iodine-125 implants for CNS tumors performed in our institution. Ten had stereotactic implantation in the brain stem region, and nine had the diagnosis of brain stem glioma (8 diffuse pontine, 1 midbrain tumor). Their ages ranged from 1.8 to 12 years. All patients had histological confirmation of malignancy (7 high-grade glioma, 2 low-grade glioma, 1 PNET). Diffuse pontine glioma patients received external beam radiation (50 Gy) followed by a fractionated stereotactic boost of 3 Gy×4 fractions. After 4–6 weeks, patients were reevaluated for stereotactic interstitial I-125 therapy. The planned implant dose was 82.9 Gy to the enhancing tumor (4 cGy per h). Preliminary results indicated that no surgical complications were associated with the catheter placement. Four patients have died (7–9 months from diagnosis) and four patients remain alive (5–38 months from diagnosis, median 10 months). Two autopsies confirmed the presence of progressive glioblastoma multiforme and intralesional necrosis. In one patient who received an implant alone for midbrain LGA, necrosis without tumor was found on biopsy after 36 months. He was successfully treated with hyperbaric oxygen therapy. The implementation of permanent I-125 implants appears to have a role in the management of pediatric CNS malignancy. This study confirms the results of previous reports regarding the safety of stereotactic interstitial brachytherapy in the brain stem. Tumor control for patients with high-grade brain stem glioma remains poor even with high focal radiation doses. Received: 10 May 1998     

Pediatric brain stem gliomas: an update

It has become evident that pediatric brain stem gliomas are a heterogeneous pathology and should be classified according to clinical and radiological criteria. This classification has contributed to better treatment and greatly improved prognosis. Based on a review of the literature, we describe the different types of brain stem astrocytomas reported, which are: cervicomedullary, exophytic, cystic, focal and diffuse. Particular attention is paid to therapeutic modalities. For the first three lesions named the treatment is surgical and oncological therapy should be evaluated only for regrowth of the mass. Focal tumors of the medulla and pons are still treated empirically (surgically and/or with radiotherapy), because a definitive therapeutic protocol has not yet been elaborated; on the other hand it is well estabilished that if the focal mass is in the midbrain this should merely be monitored by means of serial MRI, while radiotherapy should be applied in the event of the tumor's growth. Diffuse gliomas are treated with oncological therapy, and surgery (for biopsy or tumor excision) is not indicated. Five illustrative cases from our department are presented. Received: 5 October 1997     

人脑胶质瘤干细胞中IL-10的mRNA表达

目的在转录水平上检测人脑胶质瘤干细胞(BGSCs)中白介素-10(IL-10)的mRNA表达,探讨其在胶质瘤免疫及免疫治疗中的作用。方法从8例临床标本中培养出BGSCs,并通过生物学特性和免疫细胞化学方法予以鉴定。然后提取BGSCs以及相对应的原代脑胶质瘤细胞中的RNA进行实时逆转录-聚合酶链式反应(RT-PCR)检测,测定IL-10的mRNA表达水平,并予统计学分析。结果成功从8例临床标本中培养出BGSCs并通过鉴定。定量检测mRNA表达显示,在BGSCs中IL-10的mRNA表达显著高于相应的原代培养的脑胶质瘤细胞,配对t检验显示P<0.05,有统计学意义。结论首次检测了BGSCs中IL-10的mRNA表达水平,证实其高于相应的原代胶质瘤细胞。这可能是脑胶质瘤能逃避肿瘤免疫并且复发的原因,若要根治脑胶质瘤,应以BGSCs为靶点进行治疗。     

Kinetics of the uptake of [3H]paroxetine in the rat brain

Paroxetine, an antidepressant with a high affinity for serotonin (5-HT) re-uptake sites, is a potential tracer of these sites. We determined the kinetic properties of [³H]paroxetine in rat brain in vivo. Relative to [¹⁴C]iodo-antipyrine, the brain uptake index (BUI) of [³H]paroxetine was 60–70%. The unidirectional blood clearance of [³H]paroxetine were 0.05–0.12 ml g^?1 min^?1, lower than expected from the BUI values. The steady state volume of distribution was 3.5 ml hg^?1 in the diencephalon and 1.8 ml ^?1 in the cerebellum, suggesting a binding potential of unity. Autoradiographs at four hours after [³H] paroxetine injection (300 μCi, i.p.) revealed heterogenous binding consistent with the calculated binding potentials. Binding was nearly absent from cerebellum and was highest in the dorsal raphé, superior colliculus, dorsal hypothalamus, and entorhinal cortex, but did not reach equilibrium in four hours of tracer circulation. The specific binding relative to vermis was displaced by pretreatment with fluonotino (10 mg/kg, i.p.). © 1993 Wiley-Liss. Inc.     

In vivo labeling of sigma receptors in mouse brain with [3H]4-phenyl-1-(4-phenylbutyl)piperidine

4-Phenyl-1-(4-phenylbutyl)piperidine(4-PPBP) is a very potent ligand for σ (Sigma) receptors. The present study was undertaken to evaluate [³H]4-PPBPas a radioligand for in vivo labeling of cerebral σ receptors. After intravenous administration of [³H]4-PPBP to mice, there is high uptake of radioactivity in the brain. The regional distribution of radioactivity in the brain 2 h after intravenous injection of [³H]4-PPBP parallels the in vitro binding of the radioligand in rat brain (pons/medulla > cerebellum ≥ prefrontal cortex ≥ parietal cortex > hypothalamus > olfactory tubercle ≥ thalamus > hippocampus > striatum). Pretreatment with haloperidol (2 mg/kg) significantly decreases the radioactivity measured in the brain 30–120 min after injection of [³H]4-PPBP. Pretreatment with unlabeled 4-PPBP or ifenprodil also significantly decreases radioactivity in the brain 2 h after injection of [³H]4-PPBP, in a dosedependent manner. The in vivo binding of [³H]4-PPBP in the brain also is significantly inhibited by SL 82.0715, BMY 14802, 1,3-di-o-tolylguanidine (DTG), and (+)-enantiomers of pentazocine, SKF 10,047, and 3-PPP, but not by the corresponding (?)-enantiomers, consistent with stereoselectivity of inhibition obtained in in vitro binding studies. In contrast, pretreatment with dizocilpine and spiperone does not inhibit in vivo binding of [³H]4-PPBP. The results indicate that [³H]4-PPBP would be a suitable radioligand for in vivo labeling of σ receptors in brain. © 1995 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America

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Undifferentiated gliomas of the brain stem

Undifferentiated gliomas of the brain stem were confirmed surgically in two young children. The patients were treated by aggressive irradiation of the entire neuraxis, similar to that administered for medulloblastoma. Therapy resulted in a good prognosis and there was no tumor recurrence.     

Pontine gliomas causing locked-in syndrome

The terminal phase of pontine glioma is reportedly characterized by disturbance of consciousness. The authors retrospectively reviewed 8 children who died of pontine gliomas in their hospitals. The hospital records were analyzed specifically in regard to neurological status and terminal case. All children became mute and quadriplegic with cranial nerve palsies. The oldest child, 17 years in age, unquestionably showed the classical locked-in syndrome for the last 4 months. Six of the remaining 7 (average 5 years of age), while labeled as semicomatose, responded to calling by blinking and/or vertical eyeball movement. The authors consider that they were indeed awake in the locked-in state until very near death. This would raise a serious ethical problem of whether or not they should be intubated and kept ventilator-dependent at the time of respiratory failure, which often occurs.     

NF1患者大脑活动特征的PET-CT研究

目的采用正电子发射断层扫描/X射线计算机断层成像（PET-CT）检测Ⅰ型神经纤维瘤病（NF1）成年患者大脑代谢活动特征变化情况，探讨该疾病稳定状态下的特异脑活动异常情况。 方法利用PET-CT技术，结合脑内葡萄糖代谢特征分析方法，对自2018年1月至7月就诊于首都医科大学附属北京天坛医院神经外科的11例病情稳定的NF1患者（NF1组）和10例健康对照组进行全脑数据分析，运用基于Matlab的SPM软件比较NF1组与健康对照组在全脑水平上大脑各区域活动的变化。 结果NF1组与健康对照组在额叶、颞叶等区域存在不同的代谢特征。全脑分析结果显示NF1在右侧颞上回后部、中央区、额上回、额中回，双侧的颞叶内侧面、顶叶视觉区等脑区出现了与健康对照组不同的脑代谢表现，特别是在双侧丘脑区域出现了显著异常，差异具有统计学意义（P<0.05），主要表现为双侧丘脑区域的葡萄糖摄取减低，提示该区域的脑活动减弱。 结论非中枢系统病变或疾病自身基因突变引起大脑的功能代谢变化，可能为NF1患者的一项重要临床特征，也将为该类疾病以及具有同类型脑部疾病患者的康复及治疗提供前瞻指导。     

Human brain glioma stem cells are more invasive than their differentiated progeny cells in vitro

Glioma, the most commonly occurring primary intracranial tumor, remains associated with a dismal outcome, despite the availability of multimodal therapies. Recently, however, the identification of brain glioma stem cells (BGSC) has opened up new avenues for research. BGSC are now accepted as the progenitor cells of gliomas and are thought to determine the biological features of the resulting tumors. Thus, the diffuse invasiveness of gliomas should also be theoretically driven by BGSC. However, little research effort has been directed at understanding the invasiveness of BGSC. In the present study, BGSC from eight surgical glioma specimens were cultured and identified. Using Matrigel invasion assays, the invasiveness of these cells was measured and compared with that of their respective differentiated progeny cells in vitro. For all eight clinical specimens, the BGSC were significantly more invasive than their differentiated progeny cells. These findings indicate a key role for BGSC in glioma infiltration and invasion. We also found that BGSC tended to aggregate and reform into new spheres after travelling into the Matrigel, preserving some of the morphological characteristics of the suspended cells. The invasiveness of the BGSC did not correlate with the pathological grade of glioma in the present study, so further investigations using larger sample sizes are needed to better understand the mechanisms underlying the invasiveness of BGSC.     

Electrophysiological brain stem investigations in idiopathic narcolepsy

Narcolepsy is associated with various rapid eye movement (REM) sleep abnormalities. Distinct brain stem areas seem to play a prominent role in REM sleep regulation. Recent magnetic resonance imaging (MRI) studies have led to conflicting findings concerning the presence of structural brain stem lesions in patients with idiopathic narcoleptic syndrome. However, multimodal electrophysiological brain stem investigations may reveal functional brain stem abnormalities even in the absence of MRI abnormality. Therefore we investigated brain stem function in 12 idiopathic narcoleptic patients by systematically studying tegmental brain stem pathways. All of the patients met the diagnostic criteria of the International Classification of Sleep Disorders, with typical changes in polysomnography and the multiple sleep latency test. Electrophysiological investigations comprised masseter reflex, blink reflex, masseter inhibitory reflex, early auditory evoked potentials and electrooculography with vestibular testing. In no patient were electrophysiological brain stem abnormalities observed. Our findings do not support the existence of a relevant brain stem lesion in narcoleptic patients with normal neurological status. Received: 23 September 1997 Received in revised form: 23 January 1998 Accepted: 10 February 1998     

Mapping muscarinic receptors in human and baboon brain using [N-11C-methyl]-benztropine

The muscarinic cholinergic system has been mapped in vivo in human and baboon brain using [N-11C-methyl]-benztropine and high resolution positron emission tomography (PET). [N-11C-methyl]-benztropine uptake was observed in frontal, parietal, occipital, and temporal cortices as well as in subcortical structures including the corpus striatum and thalamus. Uptake continued to increase in baboon and human brain in all areas over an 80 minute experimental period with the exception of the cerebellum where the accumulation of radioactivity began to decrease by 25 minutes postinjection. The ratio of incorporation of [N-11C-methyl]-benztropine between corpus striatum/cerebellum was 1.53 and 1.46 in humans and baboons, respectively, at 60 minutes. Blocking studies in baboons using the muscarinic cholinergic antagonists scopolamine and benztropine and the muscarinic cholinergic agonist pilocarpine combined with blocking studies in humans using benztropine indicate that the binding of this compound is specific for the muscarinic cholinergic system. Pretreatment with the potent dopamine reuptake blocker nomifensine produced no effect on the incorporation of radioactivity in any baboon brain region examined. Analysis of labelled plasma metabolites indicates that in humans, the rate of metabolism of [N-11C-methyl]-benztropine is slow (83.0% unchanged at 30 minutes postinjection) differing quite dramatically from the rate of metabolism observed in baboons (43.4% unchanged at 30 minutes postinjection). These data combined with postmortem studies in humans and primates demonstrate that [N-11C-methyl]-benztropine is a suitable muscarinic cholinergic ligand for use in humans and baboons with PET.     

Moyamoya disease associated with a brain stem glioma

An 8-year-old boy was found to have primary moyamoya disease associated with a brain stem glioma. For over 3 years the child had experienced transient ischemic attacks induced by hyperventilation. One month before referral to our hospital he had presented with progressive left facial nerve palsy. Magnetic resonance imaging showed a cystic mass in the lower pons. Angiography revealed severe bilateral stenosis of the internal carotid arteries and prominent moyamoya vessels in the basal ganglia. Partial resection of the tumor yielded a histological diagnosis of pilocytic astrocytoma. Local radiation therapy reduced the size of the tumor. Anastomosis of the superficial temporal arteries and middle cerebral arteries on both sides was then performed. After direct bypass surgery, the patient remained in a good condition for a 5-year follow-up period. Clinical investigation of the coincidence of primary moyamoya disease and brain stem glioma led the authors to conclude that these two diseases coexisted independently. Received: 25 December 1998     

CT,MRI, and PET in a case of intractable epilepsy

We report the case of a child with drug-refractory partial epilepsy in whom computed tomography showed no abnormality and magnetic resonance imaging showed a noninvasive cystic lesion in the left hippocampus. The finding in the positron emission tomography study with l-[methyl-¹¹C]-methionine as a tracer suggested a tumor. This finding was confirmed histologically.     

Long-term frontal brain metabolic changes in cocaine abusers.

Neurological complications from cocaine use are well recognized. We propose that chronic cocaine use can also cause clinically silent brain dysfunction. We investigated brain glucose metabolism with positron emission tomography (PET) and 2-deoxy-2[18F] fluoro-D-glucose (FDG) in 21 neurologically intact chronic cocaine abusers (C) and 18 normal controls (N). The cocaine abusers were tested 1-6 weeks after the last use of cocaine and seven were retested after a 3 month drug-free period. Global cerebral glucose metabolism was not significantly different between controls and cocaine abusers (N = 38.4 +/- 3, C = 36.5 +/- 5 mumol/100 g of tissue, min). However, cocaine abusers had significantly (P less than 0.05) lower metabolic activity in 16 of the 21 left frontal regions and 8 of the 21 right frontal regions. These decreases persisted after 3-4 months of detoxification and were correlated with the dose (P less than or equal to 0.01) and the years of cocaine use (P less than or equal to 0.05). This study shows reduced rates of frontal metabolism in neurologically intact cocaine abusers that persist even after 3-4 months of detoxification.     

Anatomical atlas of the baboon''s brain in the orbito-meatal plane used in experimental positron emission tomography

An anatomical atlas has been constructed of the brain of the baboon (Papio papio) in the orbito-meatal plane (OM-plane) which is frequently used in experimental positron emission tomography (PET) investigations. The atlas comprises 12 photographic reproductions of histological brain sections separated by 2.5 mm intervals, and covers telencephalic to pontine brain stem levels. The anatomical atlas was used in analysis of some PET scan images obtained after administration of either a benzodiazepine (BZ) antagonist, (11C)-Ro 15-1788, or a dopamine D2 receptor antagonist, (76Br)-bromospiperone. Since PET camera detects radiation emitted from a slice of tissue of 15 mm thickness, each PET image corresponds to the tissue represented on six levels of the anatomical atlas. In optimal conditions, the PET image shows a pattern of receptor labelling reminiscent of anatomical structures in the atlas. Sometimes, however, the superimposition of different labelled structures yields a PET image which lacks any apparent resemblance with individual anatomical structures. In these cases, the analysis of the PET scan must rely on the anatomical atlas, as well as available data on the distribution of specific binding sites.     

Dysfunctional brain networks and genetic risk for schizophrenia: specific neurotransmitter systems

Multiple neurotransmitter circuits are disturbed in schizophrenia, and the dopamine hypothesis of schizophrenia prevails as the hypothesis with most empirical support. On the other hand, schizophrenia is highly heritable with a pattern consistent with both common and rare allelic variants and gene × environment interaction. Advances in the field of neuroimaging have expanded our knowledge of intermediate phenotypes, the neurobiological processes that convey the risk from the genes to the complex phenotype. In this article, we review the recent and continuously accumulating evidence from in vivo imaging studies aiming at characterizing neurochemical intermediate phenotypes of schizophrenia. Dopaminergic alterations in schizophrenia are shared by individuals at genetic risk who do not express the illness, suggesting a "dopamine hypothesis of schizophrenia vulnerability." This hypothesis has the potential to help us better understand the dopaminergic dysfunction in the context of the complex pathophysiological process leading to schizophrenia. In the future, neurotransmitter imaging studies should investigate the gene × environment interaction in schizophrenia, and try to identify neurobiological correlates of heightened sensitivity to environmental stressors (e.g., cannabis, childhood trauma, and other psychosocial stress) in genetically vulnerable individuals.     

Resistance of brain glucose metabolism to thiopental-induced CNS depression in newborn piglets

The transition from mild sedation to deep anaesthesia is marked by the phenomenon of burst suppression (BS). FDG-PET studies show that the cerebral metabolic rate for glucose (CMRglc) declines dramatically with onset of BS in the adult brain. Global CMRglc increases substantially in the post-natal period and achieves its maximum in preadolescence. However, the impact of post-natal brain development on the vulnerability of CMRglc to the onset of BS has not been documented.