Purification of amyloid plaque core proteins (APCP) from Alzheimer's disease brains to complete homogeneity and in high yield permitted its chemical fractionation and characterization of its components. APCP is mainly made of β-amyloid (βA) and an assortment of glycoproteins (accounting for 20%) rich in carbohydrates compatible with N-and O-linked saccharides. When added to tissue culture of sympathetic and sensory neurons APCP and βA inhibited neuritic sprouting, a reversible phenomenon at low doses. Higher concentrations of both substances kill the neurons in culture. APCP is significantly more toxic than βA, suggesting the minor components may play an important role in increasing the toxicity of βA. If the observed toxic effects of APCP in situ are occurring in vivo during the course of AD, then the accumulation of these extracellular proteins could be largely responsible for some of the neuronal death observed in this neuropathology.

Many biologically active tracers are available for positron emission tomography (PET) investigations, but most studies of epilepsy have utilized l8F-fluorodeoxyglucose (FDG) to measure local cerebral metabolic rate for glucose. Over 70% of patients with medically refractory partial seizures demonstrate an interictal zone of hypometabolism corresponding to the epileptogenic region. This metabolic defect commonly involves the temporal lobe in patients with complex partial seizures of mesial temporal origin, and is encountered less consistently with seizures of extratemporal neocortical origin. Although false localization is less likely with FDG-PET than with EEG, the hypometabolic zone merely reflects a focal functional deficit and its epileptogenicity must still be demonstrated electrophysiologically. When hemispherectomy or large multilobar resections are planned in small children, FDG-PET also provides useful supporting evidence that the contralateral hemisphere is functioning normally. It is difficult to obtain FDG-PET scans and to interpret results during spontaneous partial seizures. Ictal scans can be more easily obtained with single photon emission computed tomography (SPECT), which may provide information for planning surgical resections.

A 29 year old man had an accessory branch of the superficial peroneal nerve which entered the foot by rostro-caudally traversing the lateral malleolus laterally. The nerve was entrapped by a fascial band, resulting in pain over the lateral malleolus and dorsum of foot. Symptoms resolved when the nerve was surgically released.

We describe a young man with a two and a half year history of idiopathic irregular contractions of an antitragicus muscle in the absence of a more generalized movement disorder. These contractions persisted in sleep and could not be replicated voluntarily. Because proximal nerve block temporarily eliminated the movements and complex hand movements reduced their amplitude and frequency, we suspect a central generator. However, these movements were not associated with any known pathologic condition.

Synapse formation is a complex, incompletely understood process that has received only limited investigation in man despite the importance of synaptic dysfunction in common disorders such as epilepsy and mental retardation. This review explores synaptic differentiation, focussing on the morphologic maturation of synapses. Since differentiation depends on many antecedent developmental events, synaptogenesis can be affected by several factors: errors in neuronal proliferation, migration, and differentiation. The challenge to the neurobiologist is to detect and evaluate the minor alterations in neuronal differentiation that could account for the structural basis of the clinical manifestations. Trisomy 21 is an example of a condition in which the cytoarchitecture of the cerebral cortex is not obviously altered, yet mental retardation is consistently present; research neurobiologic techniques are making possible documentation of its structural basis. Epilepsy is another example in which examination of surgically removed cerebral cortex reveals subtle cortical dysplasias helpful in understanding the basis for the abnormal electrical discharge. Further exploration of synaptogenesis, particularly the influence of gene products and epigenetic factors on synapse maturation, will increase our understanding of the pathogenesis of conditions in which “morphology” seems normal but function is abnormal.

Neurologic manifestations, afflicting up to 70% of SLE patients, include psychosis, seizures, chorea, neuropathies, and stroke. MRI is useful in evaluation of lupus patients and several reports have documented cerebral atrophy or focal hyperintensities. We report an unusual MRI appearance in a 56-year-old woman with SLE, diagnosed on the basis of pleuritis, lymphopenia, anti-DNA antibodies, and neurologic involvement. She reported recent onset of Raynaud's phenomenon and generalized macular rash. She presented after two months of gradual deterioration with memory loss, flattened affect, dysphagia, dysarthria, anomia, and somnolence, without focal neurologic signs. Investigations included elevated ESR, reduced complement, normal CSF without oligoclonal bands, negative viral serology, normal hormone and vitamin levels, normal renal and hepatic function. Neuropsychologic testing showed widespread impairment (WAIS-R: FSIQ-63; WMS-69; DRS-98; RCPM-14; WAB AQ-78.8). CT was normal but MRI showed strikingly symmetric, confluent hyperintensities extensively involving cerebral and cerebellar white matter on Tl and T2 weighted scans. Basal ganglia and subependymal and subcortical white matter were spared. Treated with prednisone, the patient made a gradual, but incomplete, recovery. These MRI findings may reflect widespread vasculopathy or direct immunologic brain insult with or without imunologic blood-brain barrier disruption.

An animal model of neuronal loss induced by a murine retrovirus is described. The neurological disease is manifested by a lower limb paralysis and is characterized as a spongiform myeloencephalopathy. The primary determinant of neurovirulence has been mapped within the viral env sequences and a secondary determinant is present within the LTR region. A model of pathogenesis, suggesting that the disease is receptor-mediated, is proposed.

Rupture of cerebral aneurysms is an important cause of morbidity and mortality in patients with adult polycystic kidney disease (PKD). In the present paper, we review the literature regarding the association of cerebral aneurysms and PKD and emphasize, by means of a case report, the importance of familial clustering of aneurysms in patients with PKD. We conclude that the prevalence of intracranial aneurysms in patients with PKD approaches 40% and is likely significantly higher in patients with PKD and a positive family history for cerebral aneurysm. We recommend that screening cerebral angiography be strongly considered in all patients with PKD and a family history of cerebral aneurysm or subarachnoid hemorrhage.

Cerebral dysgenesis encompasses varied disorders of brain development. Based on the understanding of these conditions provided by histopathologists, embryologists, radiologists and developmental pediatricians, surgeons are able to appropriately assist in the care of these patients. The surgeon can offer assessment of the ventriculomegaly that commonly accompanies cerebral dysgenesis in addition to providing methods to control hydrocephalus, to reconstruct cranial and facial malformations and to remove dysfunctional tissue. For most patients, surgical intervention is only one of the many factors that determine developmental prognosis. Based on the foundation built by other specialists, this review discusses cerebral dysgenesis from the perspective of historical and current surgical interventions.

Since Idiopathic Parkinson's disease (IPD) was first described more than 170 years ago, there have been major advances in the understanding of the etiology of the disease as well as in its treatment. This article will review current knowledge concerning the role of the environment, genetic hypotheses and the aging factor in the etiology of IPD and proposes a complex interaction involving all these factors. Hypotheses regarding mitochondrial inhibition and free radical generation in IPD are discussed in relation to the mechanism of action of neurotoxins known to produce parkinsonian syndromes.

A retrospective study of 383 patients who had undergone either left or right anterior temporal lobectomy (varying with respect to the amount of hippocampus excised) revealed that there were no significant differences in surgical outcome between those patients having a large and those patients having a small hippocampal removal. Although left temporal-lobe excisions were significantly smaller than right temporal-lobe excisions, both medially and laterally, patients with left temporal-lobe removals had an overall better surgical outcome. Patients in the successful surgicaloutcome group did better than the unsuccessful surgical-outcome group on a variety of cognitive measures, including tests of intelligence, delayed verbal memory, and verbal fluency. The results suggest that, for many patients with medically intractable epilepsy, an anterior temporal lobectomy including the amygdala may suffice to reduce their seizure frequency.

This review identifies the fundamental anatomical and physiological processes that provide the substrates of maturation in the developing nervous system. Cerebral malformations may be viewed from the perspective of aberrations in one or more of these processes. The maturational processes are generally sequential but with considerable temporal precision and overlap: 1) neuronogenesis and gliogenesis, including neural induction by the notochord and primary segmentation of the nervous system; 2) programmed cell death of excess neuroblasts and glioblasts; 3) neuroblast migration; 4) formation and growth of neurites; 5) development of membrane polarity and excitability; 6) synaptogenesis; 7) biosynthesis of neurotransmitters and other secretory products; and 8) myelination of axons. The anatomical and synaptic organization of the fetal brain differs greatly from the mature state. An excess of axonal collaterals, dendritic branches, spines and synapses are formed and later selectively deleted. Transitory neurons, specialized glial cells, synaptic circuits and transient neurotransmitter systems serve as functional elements for a limited time. The clinical expression of these transitory features of the fetal brain are incompletely understood, particularly in the context of embryonic cerebral plasticity.

A patient who presented with bilateral loss of all pupillary reactions and normal ocular motor function is reported. Investigation revealed the presence of massive hydrocephalus. The syndrome developed shortly after transsphenoidal surgery for a suprasellar craniopharyngioma. Pupillary function returned to normal following the insertion of a ventriculo-peritoneal shunt. It is suggested that the syndrome was due to compression of the visceral oculomotor nuclei by a dilated sylvian aqueduct.

We have compared the relative localizing value of common tests in the presurgical evaluation of epilepsy in 73 patients with depth electrode (SEEG) confirmed epileptogenic foci and excellent surgical outcome. We found the tests of abnormality (CT, amytal, neuropsychology) to be frequently non-informative and often discordant with SEEG. The EEG was concordant with the SEEG in 38% of cases and provided lateralization in 78%. EEG was less localizing than ictal behavior in frontals but not in temporals. The need for SEEG is rather evident in these results but could become attenuated by the development of the localizing power of scalp EEG.

Altered chromatin conformation and increased amounts of aluminum have been observed in the brains of patients with Alzheimer disease. These factors have been shown to affect gene regulation. In this report, we describe how these changes may selectively alter the pool size of the human light chain neurofilament gene and play a fundamental role in the expression of this disease.

Less than 10 years have passed since the discovery that 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is capable of producing parkinsonism in both humans and non-human primates. In that time, there has been considerable interest in the possibility that the pathogenesis of idiopathic Parkinson's disease (PD) might involve a process analogous to that of MPTP toxicity. One hypothesis holds that PD might arise, at least in part, from exposure to an MPTP-like environmental toxin. Rapid progress has been made towards elucidating the precise mechanism by which MPTP exerts toxicity, and clarifying the relationship of MPTP toxicity to idiopathic PD. The goal of these efforts is to develop a therapy that inhibits the underlying disease process in PD.

A Caucasian girl developed slowly progressive sensory neural deafness and bulbar and spinal muscle weakness typical of the Vialetto-Van Laere syndrome. As the condition progressed the major disabilities became dysphagia, respiratory muscle weakness and postural hypotension. Treatment with gastrostomy feedings, oxygen and fludrocortisone acetate produced worthwhile functional improvement.

We report the pathological and molecular biological findings of human T-cell lymphotropic virus type 1 (HTLV-1) infection of the spinal cord in a patient with a chronic progressive myelopathy. Light microscopy disclosed loss of myelin and axons, thickening of blood vessels and a lymphocytic cell infiltrate in the spinal cord especially at the cervical and thoracic levels. Electron microscopy confirmed the vascuolar appearance seen with light microscopy but virus particles were not observed. The HTLV-1 gag gene could be amplified (by polymerase chain reaction) from cervical spinal cord tissue while not from elsewhere in the neuroaxis. The presence of HTLV-1 geonomic material in spinal cord tissue has not been previously reported.