Clinical and experimental neurology最新文献

Thomas Willis (1621-1675), arguably the founding father of neurology, devised an interpretation of neurophysiology which involved motor function being mediated by explosions in nerve tissue and muscle, facilitated by the temporary development of an explosive Copula comprising short-lived aggregates of 'nitrous' and 'sulphur' particles i.e. the components of gunpowder. Seen from a modern standpoint, such a concept is manifestly absurd. However, seen from the standpoint of the Paracelsian iatrochemistry to which Willis subscribed, and understood in the spirit of analogy which he probably intended, Willis' interpretation can be regarded as the beginning of the application of bioenergetics to neural function.

Ipsilateral hemispheric ischaemia related to permanent or temporary arterial occlusion at the time of operation is a potential risk of surgery upon some aneurysms or tumours which involve the internal carotid artery. Presurgical evaluation of the risks of temporary or permanent internal carotid artery occlusion may help predict patients in these circumstances at risk of stroke. Balloon test occlusion studies involve the elective preoperative occlusion of the internal carotid artery by a deflatable balloon inserted into the cerebral circulation under angiographic control. We have performed 16 balloon test occlusion studies; 2 subjects developed clinical and electroencephalographic changes when the carotid artery was temporarily occluded, and these changes reverted to normal when the balloon was deflated. The results of the test occlusion studies helped in planning the surgical management of all the subjects involved.

A double-blind, randomized and placebo-controlled trial was conducted on 110 Chinese patients with ischaemic stroke who were stratified into 2 subtypes (cortical and lacunar infarcts) according to their clinical and CT findings. Treatment was started within 36-48 hours after the stroke onset. Pentoxifylline was administered intravenously in a dose of 600 mg daily for 5 days, together with oral aspirin 150 mg daily. Neurological deficits were scored on admission and at one week. Demographic data were comparable between the treatment and placebo groups. For cortical infarcts, there were significantly more patients in the placebo group who deteriorated and died than in the treatment group (p < 0.02). As for the lacunar infarcts, there was no difference between groups in the numbers of patients who improved or deteriorated. Our study shows that the positive effect of pentoxifylline can be demonstrated only in patients with cortical infarction. Early deterioration and mortality were significantly decreased in these patients. The clinical course of lacunar infarction was not affected by pentoxifylline. It is not clear whether aspirin may potentiate the antiplatelet function of pentoxifylline and contribute to its temporary clinical efficacy in this way.

We aimed to determine the site of ictal foci and the pathogenesis of seizures in 4 infants with intractable seizures. The patients were studied using simultaneous video and electroencephalographic (EEG) monitoring, structural studies and ictal and interictal single photon emission computed tomography (SPECT). Ictal neurophysiology showed multifocal seizure propagation in Patients 1 and 2 and generalised abnormal electrical patterns in Patients 2, 3 and 4. Magnetic resonance imaging (MRI) demonstrated a focal abnormality in Patient 4. SPECT studies showed focal or multifocal increased uptake in 3 subjects (Patients 1,3,4) and increased uptake in the thalamic and basal ganglia regions of 2 subjects (Patients 2,3). SPECT studies contributed to an understanding of the pathogenesis of seizure initiation and propagation in the 4 patients studied.

The new anticonvulsant vigabatrin (gamma-vinyl-gamma-aminobutyric acid) is normally supplied as a racemate, but its anticonvulsant effect is thought to reside in its [S]-enantiomer only. The plasma concentration ratio of the [R] to [S] enantiomers appears to remain constant across the vigabatrin dosage interval in adult volunteers, and in the present study this has also proved to be the case in 12 chronically treated adult epileptic patients. However, in 8 epileptic children chronically treated with other anticonvulsants and given add-on vigabatrin therapy because of failure to control seizures, plasma [R]:[S]-vigabatrin ratios changed across the drug dosage interval, the [R]-vigabatrin levels tending to be relatively higher soon after intake, and to fall more rapidly than the [S]-vigabatrin concentrations over the next few hours (mean half-lives 2.52 +/- SD 0.49 and 6.53 +/- SD 6.62 hours). The reason for the shorter half-life of [R]-vigabatrin in children remains to be elucidated, but it appears that measurement of racemic vigabatrin plasma concentrations in children, though not in adults, may lead to somewhat misleading conclusions as regards the amount of the circulating anticonvulsant [S]-vigabatrin.

Nine patients (mean age 73 years: range 62-83 years) are described with a characteristic tremor or instability of the trunk and lower limbs which occurred when standing still, and which was either diminished or abolished by walking. Three had essential tremor of the upper limbs. The duration of the disorder ranged between 4 months and 20 years (mean 5 years). In all cases the condition worsened with time. Eight patients responded to clonazepam (0.5 to 2.0 mg per day) and one to chlordiazepoxide (30 mg per day). Orthostatic tremor is a disabling condition that responds to benzodiazepine treatment and may be more frequent than previously recognised.

An acute myopathy complicating life-threatening asthma has been reported with increasing frequency. We present a further 3 patients with this complication. Each patient had nerve conduction studies, electromyography and muscle biopsy performed. The records of a cohort of 12 patients, ventilated in an intensive care unit over a 16 month period, were reviewed. Eleven out of the 12 patients developed an elevated creatine kinase level (median 1311 U/L, range 185-9973 U/L) and 4 developed symptomatic weakness. The myopathy of status asthmaticus is not a homogeneous clinicopathological entity. Although myopathy is the predominant feature, there is a neuropathic component in some patients. Full recovery is usual. The combination of corticosteroids and neuromuscular blocking agents has been proposed as the possible cause of the complication.

Basilar artery occlusion developed in a 34 year old woman 2 months after adopting unusual neck postures during yoga practice. On angiography, her basilar artery was filled with intraluminal clot while the vertebral arteries were normal. We postulate that a severe reduction in blood flow and possibly an intimal tear triggered thrombosis of the vertebral artery and that the final stroke mechanism was artery-to-artery embolism.

There is both experimental and clinical evidence to suggest a role for 5-hydroxytryptamine (5-HT) in Parkinson's disease. The effect of ritanserin, a highly selective 5-HT2 receptor antagonist, on Parkinsonian symptomatology was investigated in 10 patients in a single-blind placebo-controlled study. Akinesia and gait improved significantly in a dose-dependent manner in 5 and 7 patients respectively. However there was no significant improvement in tremor. The effects of ritanserin on akinesia and gait are consistent with a role for 5-HT in Parkinson's disease.