Abstracts A1–A10

Journal of Neurology -     

A neurosurgeon in Iraq: A personal perspective

The practice of neurosurgery in a war zone provides enormous challenges and risks for the individual surgeon working in such an austere and hostile environment, but also provides a unique opportunity to treat a high volume of severe penetrating and blast injuries to the head, neck and the spine. The purpose of this article is to present the author's personal experiences and perspective as a military neurosurgeon working in the US Airforce Hospital in Balad (the 332nd Expeditionary Medical Group) Iraq in for 3 months in 2004. Strategies for managing the mass casualties, and the severe penetrating craniofacial trauma are presented and the reasons for the low mortality of troops injured in Iraq are discussed.     

A catalog of SCN1A variants

Over the past 10 years mutations in voltage-gated sodium channels (Na(v)s) have become closely associated with inheritable forms of epilepsy. One isoform in particular, Na(v)1.1 (gene symbol SCN1A), appears to be a superculprit, registering with more than 330 mutations to date. The associated phenotypes range from benign febrile seizures to extremely serious conditions, such as Dravet's syndrome (SMEI). Despite the wealth of information, mutational analyses are cumbersome, owing to inconsistencies among the Na(v)1.1 sequences to which different research groups refer. Splicing variability is the core problem: Na(v)1.1 co-exists in three isoforms, two of them lack 11 or 28 amino acids compared to full-length Na(v).1.1. This review establishes a standardized nomenclature for Na(v)1.1 variants so as to provide a platform from which future mutation analyses can be started without need for up-front data normalization. An online resource--SCN1A infobase--is introduced.     

A clinically isolated syndrome: A challenging entity

Abstract   Acute isolated neurological syndromes, such as optic neuropathy or transverse myelopathy, may cause diagnostic problems since they can be the first presentations of a number of diseases such as multiple sclerosis (MS) and collageneous tissue disorders. In the present study, particular systemic lupus erythematosus (SLE) and primary Sjogren syndrome (pSS) patients, who were followed up with the initial diagnosis of possible MS with no evidence of collagen tissue disorders for several years, are described. Five patients with the final diagnosis of SLE and five pSS patients are evaluated with their neurologic, systemic and radiologic findings. Over several years, all developed some systemic symptoms like arthritis, arthralgia, headache, dry mouth and eyes unexpected in MS. During the regular and close follow-up laboratory evaluations of vasculitic markers revealed positivity, leading to the final definite diagnosis of SLE or pSS. Patients with atypical neurological presentation of MS, a relapsing remitting clinical profile, or lack of response to the regular MS treatment should be evaluated for the presence of a connective tissue disease. Various laboratory tests, such as cerebrospinal fluid findings, autoantibodies profile, markers, cranial and spinal magnetic resonance imaging, can be helpful for the differential diagnosis. Lack of response to the regular multiple sclerosis treatment, even increasing rate of relapses can force the clinician for the differential diagnosis. In particular cases an accurate diagnosis can only be made after close follow-up.     

A SOCIAL PSYCHIATRIC INVESTIGATION OF A RURAL DISTRICT IN NORTHERN NORWAY: A PRELIMINARY COMMUNICATION

The psychiatric morbidity of Berlevaag in Northern Norway (71 degrees North) was studied in 1944 by Bremer A follow-up and a re-examination of the persons in the community was initiated in 1972. Preliminary data suggest that the prevalence of psychoses is practically the same in 1973 as in 1944. Various registers have provided a fairly complete count of psychoses even before the onset of an intensive field study. Only a minor part of the nonpsychotic psychiatric disorders appears to have been identified.     

Targeting adenosine A2A receptors in Parkinson's disease

The adenosine A2A receptor has emerged as an attractive non-dopaminergic target in the pursuit of improved therapy for Parkinson's disease (PD), based in part on its unique CNS distribution. It is highly enriched in striatopallidal neurons and can form functional heteromeric complexes with other G-protein-coupled receptors, including dopamine D2, metabotropic glutamate mGlu5 and adenosine A1 receptors. Blockade of the adenosine A2A receptor in striatopallidal neurons reduces postsynaptic effects of dopamine depletion, and in turn lessens the motor deficits of PD. A2A antagonists might partially improve not only the symptoms of PD but also its course, by slowing the underlying neurodegeneration and reducing the maladaptive neuroplasticity that complicates standard 'dopamine replacement' treatments. Thus, we review here a prime example of translational neuroscience, through which antagonism of A2A receptors has now entered the arena of clinical trials with realistic prospects for advancing PD therapeutics.     

A life-sustaining function for REM sleep: A theory

A hypothesis has been advanced that the primary function of rapid eye movement (REM) sleep is to provide periodic endogenous stimulation to the brain which serves to maintain minimum requisite levels of CNS activity throughout sleep. REM, in effect, is the mechanism used by the brain to promote and ensure recovery from sleep. Failures of REM may hinder, or in extreme cases, prevent arousal from sleep. The possibility that two fatal sleep-associated syndromes (Sudden Infant Death Syndrome and the Oriental Nocturnal Death Syndrome) may involve deficits of REM was discussed.     

Sodium channels SCN1A,SCN2A and SCN3A in familial autism

Autism is a psychiatric disorder with estimated heritability of 90%. One-third of autistic individuals experience seizures. A susceptibility locus for autism was mapped near a cluster of voltage-gated sodium channel genes on chromosome 2. Mutations in two of these genes, SCN1A and SCN2A, result in the seizure disorder GEFS+. To evaluate these sodium channel genes as candidates for the autism susceptibility locus, we screened for variation in coding exons and splice sites in 117 multiplex autism families. A total of 27 kb of coding sequence and 3 kb of intron sequence were screened. Only six families carried variants with potential effects on sodium channel function. Five coding variants and one lariat branchpoint mutation were each observed in a single family, but were not present in controls. The variant R1902C in SCN2A is located in the calmodulin binding site and was found to reduce binding affinity for calcium-bound calmodulin. R542Q in SCN1A was observed in one autism family and had previously been identified in a patient with juvenile myoclonic epilepsy. The effect of the lariat branchpoint mutation was tested in cultured lymphoblasts. Additional population studies and functional tests will be required to evaluate pathogenicity of the coding and lariat site variants. SNP density was 1/kb in the genomic sequence screened. We report 38 sodium channel SNPs that will be useful in future association and linkage studies.     

A MORPHOMETRIC STUDY OF THE MICROVASCULATURE OF A RAT GLIOMA

Intracerebral tumours were produced in BD IX rats by the inoculation of neoplastic astrocytes. Following perfusion-fixation, 1.0 micron sections were stained with toluidine-blue and photographed so as to construct photomontages embracing deep tumour, tumour edge and surrounding brain. Thirteen montages from 9 tumours were studied. Successive 200 micron samples were analysed with a digitizing tablet and, for each sample the following were measured: the number of vascular profiles per unit area, the mean vessel circumference and diameter and the approximate fractions of the sample occupied by tumour and necrosis. Towards the tumour centre, vascular density dropped to 20% of that for normal cortex but vessel size more than doubled. The surface area fraction of the vessels reached a maximum at the tumour edge. These results provide not only an anatomical framework for both a variety of physiological studies and for the investigation of angiogenesis in this system but also have pharmacokinetic implications for the treatment of brain tumours.     

Enabling role of adenosine A1 receptors in adenosine A2A receptor-mediated striatal expression of c-fos

When striatal neurons are strongly activated they produce adenosine, which activates nearby adenosine A1 receptors (A1Rs) and adenosine A2A receptors (A2ARs). Although the effects of A1R or A2AR activation on neural activity in the striatum have been examined separately, the effects of coactivating both receptors has not been investigated. Using c-Fos immunohistochemistry as an indicator of neural activity, we examined the effects of coactivation of A1Rs and A2ARs on neural activity and their mechanism of interaction in the caudate-putamen, nucleus accumbens (NAc) and prefrontal cortex in rats. Administration of a motor-depressant dose of the A2AR agonist CGS 21680 (0.5 mg/kg i.p.) did not significantly induce c-fos expression in any of these brain regions. Administration of a motor-depressant dose of the A1R agonist CPA (0.3 mg/kg, i.p.) produced a small but significant induction of c-fos expression only in the shell of the NAc. Coadministration of CGS 21680 and CPA produced a synergistic induction of c-fos expression in the caudate-putamen, cingulate cortex, and especially the NAc. In the shell of the NAc administration of CPA significantly decreased extracellular dopamine levels measured by in vivo microdialysis and blocked CGS 21680-induced increases in dopamine levels. Because it has been previously shown that activation of dopamine D2 receptors (D2Rs) by endogenous dopamine blocks A2AR-mediated c-fos expression, it is hypothesized that the enabling role of A1Rs in A2AR-mediated striatal c-fos expression is related to the A1R-mediated inhibition of dopamine release.