The major input and output pathways of the mammalian striatum have been well established. Recent studies have identified a number of neurotransmitters used by these pathways as well as by striatal interneurons, and have begun to unravel their synaptic connections. The major output neurons have been identified as medium spiny neurons which contain ɣ-aminobutyric acid (GABA), endogeneous opioids, and substance P. These neurons project to the pallidum and substantia nigra in a topographic and probably chemically organized manner. The major striatal afferents from the cerebral cortex, thalamus, and substantia nigra terminate, at least in part, on these striatal projection neurons. Striatal interneurons contain acetylcholine, GABA, and somatostatin plus neuropeptide Y, and appear to synapse on striatal projection neurons. In recent years, much activity has been directed to the neurochemical and hodological heterogeneities which occur at a macroscopic level in the striatum. This has led to the concept of a patch-matrix organization in the striatum.

Two children born with birth defects after intrauterine exposure to valproic acid are reported. The mothers took the drug throughout pregnancy as sole treatment for primary generalized epilepsy. The first baby showed facial dysmorphism, arachnodactyly and triphalangeal thumbs. The second had facial dysmorphism, severe laryngeal hypoplasia, tracheomalacia and an aberrant innominate artery that caused tracheal compression. A left superior vena cava, abnormal pulmonary lobulation, and unilateral hydronephrosis were also found at autopsy. Valproic acid has probable teratogenic potential in humans but the number of reported cases is few and the spectrum of anomalies is broad so it is not possible to delineate a definite fetal valproate syndrome.

A patient is described who, while on valproic acid monotherapy, developed reversible shrinkage of the brain, documented by computerized tomography with associated cognitive deficit. Although pseudoatrophy has been reported with steroid therapy, this is the first implication of an anticonvulsant drug in the etiology of that condition.

The study of neurotransmitter receptors aids in the understanding of the normal anatomy, pharmacology, therapeutics and pathophysiology of disease processes involving the basal ganglia. Receptors may be studied in vitro by homogenate binding experiments, enzyme analysis or quantitative autoradiography and in vivo with positron emission tomography. In the substantia nigra (SN), receptors have been identified for somatostatin, neurotensin, substance P, glycine, benzodiazepine and GABA, opiates, dopamine, angiotensin converting enzyme (ACE) and serotonin. The striatum has receptors for dopamine, GABA and benzodiazepines, acetylcholine, opiates, substance P, glutamate and cholecystokinin. GABA and benzodiazepine receptors are also located in the globus pallidus. In Parkinson's disease, striatal dopamine D-2 receptors are elevated in patients that have not received L-DOPA therapy. This supersensitivity is reversed with agonist therapy. Muscarinic binding to cholinergic receptors seems to correlate with dopamine receptors. Delta opiate receptors are increased in the caudate and mu binding is reduced in the striatum. In the SN of patients with Parkinson's disease, there is reduced binding of somatostatin, neurotensin, mu and kappa opiates, benzodiazepine and GABA and glycine. In Huntington's disease, there is reduced binding of GABA and benzodiazepines, dopamine, acetylcholine, glutamate and CCK. There is increased binding of GABA in both the SN and globus pallidus. Glycine binding is increased in the substantia nigra and ACE is reduced.

We report the case of a 26 year old obese woman who presented with intermittent headaches and blurred vision in her left eye (OS) and on clinical examination had an enlarged visual field blind spot OS with OS disc edema. After an extensive neurologic work up including two nondiagnostic lumbar punctures, a clinical diagnosis of OS anterior ischemic optic neuropathy was made. Gradual progression of visual field loss OS prompted reassessment of the diagnosis and intracranial pressure was confirmed to be markedly elevated by usage of a subarachnoid monitoring bolt, thus establishing the diagnosis of pseudotumour cerebri. An optic nerve sheath fenestration was performed OS with subsequent reversal of the progressive visual field loss.

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.

We report the case of a patient who at age 39 first developed an episode of muscle weakness and transient ketoacidosis with biopsy proven fatty infiltration of the liver. Over the next several years, myopathy ensued; biopsy revealed extensive deposition of lipid globules in type 1 muscle fibres. Further investigations established the diagnosis of systemic carnitine deficiency (SCD) with skeletal muscle, hepatic, and cardiac involvement. The patient has benefited from L-carnitine supplementation. Our case represents an unusually late onset of SCD and highlights the necessity, when appropriate, of a high index of suspicion of this rare but treatable disorder.

The neuropsychological findings in twin brothers with familial fatal Parkinsonism are reported. Post-mortem examination had shown extensive pathology in basal ganglia and brainstem, but not in the cerebral cortex. Although both showed average intelligence three months prior to death, they had impairment on a sorting task and in serial attention span. Some possible neural mechanisms are discussed.

The existence of subtypes of dopamine receptors as defined by Kebabian and Calne is now well accepted. The Dl receptor is typically associated with stimulation of adenylate cyclase, while the D2 receptor is either independent of adenylate cyclase or mediates its inhibition. Considerable interest has been generated by the potential physiological and clinical roles of these receptor subtypes. Availability of agonists and antagonists specifically acting at the D1 or D2 receptor site has stimulated research to characterize the functional effects of each receptor subtype. This might facilitate the development of effective compounds to control the signs and symptoms of Parkinson's disease and perhaps prevent the induction of debilitating side effects. Recent evidence indicates that Dl receptor stimulation is required to obtain full expression of the D2 receptor site, which has typically been associated with the clinical benefits of dopaminergic therapy. Both pre- and postsynaptic location of the receptors must also be taken into consideration as well as involvement of other neuronal systems. It appears that in PD, progressive involvement of the dopaminergic pathways is the principal pathological course, however, noradrenergic and serotonergic pathways are likewise involved. This multineuronal involvement suggests that drugs acting specifically at receptor sites, located on both pre- and postsynaptic neurons, might be required at different times during the course of the disease process to control its symptoms and/or the complications occurring after long-term treatment with a given drug.

Cerebral edema is a well-known complication of malignant astrocytoma and metastatic brain tumour. Though far less frequent, the association of cerebral edema with meningioma is also recognized; this is unpredictable and sometimes out of proportion to tumour size. We describe three cases where the mass effect was due to severe edema, rather than the tumour itself and was responsible for a catastrophic clinical presentation. The mechanisms responsible for the development of severe edema with meningioma which have been previously proposed are reviewed. They include tumour size, location, histologic subtype, cellularity, mitotic activity, vascularity and the presence of excretory-secretory activity. None of these consistently correlate with cerebral edema. Our cases suggest that spontaneous hemorrhage into the tumour may be the common factor responsible for severe cerebral edema. It is stressed that though a decidedly rare complication, cerebral edema secondary to meningioma should be entertained in the differential diagnosis of acute neurologic deterioration of these patients.

We have modified the techniques of Lindstrom and of Tindall to measure serum acetylcholine receptor antibody using human antigen bound to 125I-alpha Bungarotoxin. By using 10 ä1 of serum and precipitating antigen-antibody complexes with an excess of staph A, we found that only one out of 43 patients with clinically diagnosed active generalized Myasthenia Gravis had no antibodies. In pooling these results with the results of tests done for diagnostic purposes we found positive results in 54/55 generalized active MG, 8/21 MG in remission, 16/37 ocular MG and 0/55 healthy controls. Two out of 38 non MG were also positive and their clinical diagnosis of botulism and penicillamine treated rheumatoid arthritis have been confirmed by a one year follow-up. Most of these sera were also tested for reactivity with fetal calf AchR. Six out of 49 samples positive with the human receptor were negative with calf receptor. We conclude that our technique is extremely useful for the diagnosis of Myasthenia Gravis and that fetal calf antigen cannot replace human antigen in the assay.

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.

Descriptive data from several studies suggest variations in the frequency of Parkinson's disease in different population groups. Door-to-door surveys were carried out among a biracial U.S. population (blacks and whites) and in communities in Nigeria and the People's Republic of China. The U.S. investigation revealed no substantial differences in the age-adjusted prevalence ratios by race. However, blacks in Nigeria have a much lower prevalence ratio than blacks in the U. S., suggesting an environmental etiologic factor. Prevalence ratios derived from China are also lower than the U.S. figures. Studies of temporal trends in the incidence rates in one U.S. population (Rochester, Minnesota) show virtually no change over 35 years, indicating that the primary cause(s) of Parkinson's disease must have been present in this nonindustrialized community for many years. Analytic studies generally reveal an inverse association between Parkinson's disease and cigarette smoking, although epidemiologic evidence does not support a direct protective effect of smoking. Preliminary investigations suggest an increased risk associated with the rural environment and the consumption of well water. Further studies are required to discover as yet unknown environmental factors that heighten the risk of Parkinson's disease.

We report here six families with Parkinson's disease in whom the onset of symptoms tended to occur at approximately the same time irrespective of the age of the patient. The mean difference in the time of onset in different generations was 4.6 years while the mean difference in age of onset in children and parents was 25.2 years. We construe this pattern of age separation within families as suggestive of an environmental rather than genetic cause. Support for this view derives from the lack of correlation between occurrence of the disease and the degree of consanguinity. We conclude that our findings are in accord with the hypothesis which attributes the cause of some cases of Parkinson's disease to early, subclinical environmental damage followed by age-related attrition of neurons within the central nervous system.

A 60 year old man with chronic lymphocytic leukemia (CLL) developed a subacute neurological illness associated with multiple contrast enhancing lesions on CT scan. At autopsy large demyelinating lesions characteristic of progressive multifocal leukoencephalopathy (PML) were found in the right cerebral hemisphere surrounded by a dense leukemic infiltrate. The areas of contrast enhancement, highly unusual for PML, coincided with the CLL infiltrate.