The relationship between the morphology of astrocytomas and their prognosis is complex, with the localization of the tumour, the predominant cell type and the degree of anaplasia all playing an important part in determining the patient's future. Since many astrocytomas have a diversity of patterns, small needle biopsies taken from just one or a few areas may fail to elucidate the principal features of a given tumour. In addition to the astrocytoma subtypes listed in the WHO's International Histological Classification of brain tumours, new entities have been observed in the last few years. These include lipidized forms, such as the relatively benign pleomorphic xanthoastrocytoma and the highly malignant lipidized glioblastoma. Neoplastic astrocytes are capable of forming basal laminae and of phagocytosis, and often contain alpha-1-antitrypsin, features that may lead to confusing them with histiocytes. They may be arranged in a whorled pattern imitating meningiomas, their myxoid intercellular stroma may assume the morphology of cartilage and closely packed tumour cells in “epitheloid” astrocytomas come close to imitate metastatic carcinoma. Some astrocytomas contain cells indistinguishable from those of granular cell tumours of other tissues. The presence of reactive lymphocytes in astrocytomas and reactive astrocytes in malignant lymphomas can be the source of confusion between those two kinds of neoplasms.

There is much current interest in excitatory amino acids and their receptors because of their postulated involvement in several disorders of the nervous system. They function as neurotransmitters, but can act as neurotoxins in some situations. They have been implicated in the pathogenesis of cerebral hypoxic/ischemic and hypoglycemic damage, in epilepsy, in some degenerative diseases, and in some forms of neurotoxin-induced cerebral dysfunction. These diseases may reflect abnormality in a system which has evolved to provide synaptic plasticity essential for learning and memory. The purpose of this paper is to explore the ramifications of such a hypothesis.

Six patients with an aortoiliac vascular disease and a peripheral neurological deficit are presented. Clinical and electromyographic findings revealed lumbosacral plexus, sciatic and femoral nerve lesions. A correlation is made between the level of the vascular lesion (aortic, aortoiliac or distally) and the type of peripheral nerve deficit observed. In a patient complaining of pain, weakness, or numbness in a leg, the differential diagnosis should include aortoiliac vascular disease. The peripheral neurological symptoms may be the initial manifestation of the vascular disease or may appear in the early post-operative period.

Although carotid endarterectomy is a common surgical procedure in North America, controversies exist regarding the type of anesthesia, the use of indwelling shunts and the need for intraoperative cerebral monitoring. We present a prospective study of 100 carotid endarterectomies performed over a three year period by a single surgeon without the use of indwelling shunts, patch grafts, or EEG monitoring. The combined stroke and mortality rate was 1%. Our results confirm those of other authors; that indwelling shunts and EEG monitoring are not absolutely essential for a satisfactory outcome in carotid endarterectomies.

Twenty-six (41%) of 63 consecutive patients with triphasic waves had various types of metabolic encephalopathies while 37 patients (59%) had non-metabolic encephalopathies, usually senile dementia. Triphasic waves were not found to be specific for any single type of metabolic encephalopathy.

Etiology was more closely linked to conscious level at recording than any morphological or distributional feature of the triphasic waves themselves. Thus, all 31 alert patients had non-metabolic encephalopathies while all 13 comatose patients had metabolic encephalopathies.

The second, positive, component (Wave II) most often had the highest voltage while equally maximal Waves I and II occurred next most commonly. Triphasic waves were most often maximally expressed anteriorly.

Among patients with metabolic encephalopathies, a posterior-anterior delay or lag of the wave II peak occurred more commonly than did the better known anterior-posterior lag. Lags occurred with both metabolic and nonmetabolic conditions, but were more common with the former. No difference in quantity or mode of appearance existed between the metabolic and non-metabolic groups when matched for conscious level.

Prognosis for patients with either metabolic or non-metabolic encephalopathies was unfavourable. Only 4 of 24 metabolic and one of 35 non-metabolic patients were well at follow-up over 2 years later.

Forty percent of EEGs with sharp and slow wave complexes (slow spike waves) had sporadically-appearing triphasic waves. The relative amplitudes of the 3 components differed from triphasic waves in other conditions: equally maximal Waves II and III were the most usual form.

Explants of 21 neurofibromas from 16 patients with Von Recklinghausen neurofibromatosis (NF-I) plus tumour tissue from 5 comparison patients and normal tissue from one of the NF-I patients were assayed for neuronal growth factor(s) using dissociated embryonic sensory neurons from chick embryo. Twenty-one of 21 neurofibroma explants released detectable quantities of neuronal growth factors, but only 2 of 8 non-neurofibroma tissue explants released activity.

While antiserum to mouse nerve growth factor (NGF) fractionally inhibited neurite outgrowth induced by some of the neurofibromas, overall differences between assays containing antibody and controls reached statistical significance in 3 cases; in one case, explants of a separate tumourfrom the same patient had no detectable NGF-like activity.

These data support the hypothesis that local release of neuronal growth factors in neurofibromas are responsible for neurites observed within these tumours. Further evidence that endoneurial tissue of peripheral nerve is a rich source of heterogeneous neuronal growth facts has been provided by these studies.

The effectiveness of indomethacin treatment (1 mg/kg) as an antipyretic was tested in patients after cranial trauma or brain surgery involving the centromedial forebrain. Indomethacin was effective in reducing temperature in 10 of 11 cases which showed a dipyrone-resistant hyperthermia developing in the first 24 hours after brain damage, while no significant antipyretic effect was seen in hyperthermic cases developing more than 72 hours after cranial trauma or brain surgery. Biochemical tests estimating the effect of indomethacin, and pyrazolone derivatives on the arachidonic acid metabolism showed significant effects of indomethacin only in influencing cyclooxygenase activity and no effect of any drugs on lipoxy — genase actions. In view of these observations, the use of indomethacin is recommended as a treatment for neurogenic hyperthermia.

Two cases of lumbosacral root cysts of different etiology are reported. Their specific radiographic features are described using the combined technique of metrizamide myelography followed by computerized tomography of the spine. The terminology of intraspinal cysts is reviewed and their distinguishing features discussed.

A patient with bilateral homonymous hemianopia with preservation of the central vision, spatial disorientation and memory deficits secondary to bilateral occipital and mesial temporal infarctions, is presented. The cerebral damage followed a subdural hematoma with tentorial herniation and compression of both posterior cerebral arteries.

Treatment of paramyotonia congenita with acetazolamide has been shown to reduce myotonic symptoms but severe weakness has developed in some patients leading to a recommendation not to use the drug in this disorder. We studied a patient with the characteristic clinical and electrophysiological profile of paramyotonia congenita. Myotonia was effectively treated with a very low dose of acetazolamide and no weakness developed. We conclude that acetazolamide can be a safe and effective medication in paramyotonia congenita.

A twenty-eight year old woman presenting with subarachnoid hemorrhage was found at angiography to have a left anterior cerebral-anterior communicating artery aneurysm. Also identified was a fenestration of the right supraclinoid internal carotid artery with an associated accessory middle cerebral artery. This appears to be the second reported case of fenestration of the intracranial internal carotid artery. Fenestrations of cerebral vessels and their possible embryologic origins are briefly reviewed.

A young man developed virologically proved hydrophobic rabies three months after being scratched on the cheek by a bat in Northern Alberta. He became comatose after 8 days and died 5 weeks after vigorous therapy with immune globulin, interferon and Vidarabine, and excellent maintenance of oxygenation. Electroencephalographic deterioration was gradual. At postmortem examination, the brain showed widespread loss of nerve cells, mild diffuse inflammatory changes and no Negri bodies. The lesions of massive laminar necrosis of the cerebral cortex, total loss of Purkinje cells with preservation of the granule cell layer, and severe softening of the amygdala are attributed to direct viral action rather than to anoxia or brain swelling with respirator brain.

Pineal tumours are commonly of germ cell origin. The endodermal sinus tumour is a rare histologic subtype that is highly malignant and radioresistant. A single case is described and compared to six reported intracranial cases in which chemotherapy was used in addition to surgery and/or radiation. Although a beneficial effect of chemotherapy cannot be proven, the probable benefit in non-CNS cases requires that it be strongly considered. A uniform approach to diagnosis, investigation and treatment for intracranial tumours of this type is suggested.

Although relatively uncommon, interhemispheric subdural hematoma (ISDH) occurs more frequently than was suspected before the advent of computerized tomographic (CT) scanning. When its mass is sufficiently large to compress the medial cerebral hemisphere, specific focal neurological abnormalities may occur. These include weakness of the contralateral leg, or contralateral hemiparesis with the leg being weaker than the arm. On the unenhanced CT scan ISDH is seen as a crescent shaped, midline hyperdensity. Treatment is dictated by the clinical course. Evacuation of the hematoma by parasagittal craniotomy is recommended if the symptoms are pronounced.

We report a case of primary CNS lymphoma in which complete, though temporary, spontaneous clinical and radiologic remission occurred. This is the first such case report to our knowledge.