Spastin, a new AAA protein, is altered in the most frequent form of autosomal dominant spastic paraplegia

Autosomal dominant hereditary spastic paraplegia (AD-HSP) is a genetically heterogeneous neurodegenerative disorder characterized by progressive spasticity of the lower limbs. Among the four loci causing AD-HSP identified so far, the SPG4 locus at chromosome 2p2-1p22 has been shown to account for 40-50% of all AD-HSP families. Using a positional cloning strategy based on obtaining sequence of the entire SPG4 interval, we identified a candidate gene encoding a new member of the AAA protein family, which we named spastin. Sequence analysis of this gene in seven SPG4-linked pedigrees revealed several DNA modifications, including missense, nonsense and splice-site mutations. Both SPG4 and its mouse orthologue were shown to be expressed early and ubiquitously in fetal and adult tissues. The sequence homologies and putative subcellular localization of spastin suggest that this ATPase is involved in the assembly or function of nuclear protein complexes.

Mutations in the fukutin-related protein gene (FKRP) identify limb girdle muscular dystrophy 2I as a milder allelic variant of congenital muscular dystrophy MDC1C

The limb girdle and congenital muscular dystrophies (LGMD and CMD) are characterized by skeletal muscle weakness and dystrophic muscle changes. The onset of symptoms in CMD is within the first few months of life, whereas in LGMD they can occur in late childhood, adolescence or adult life. We have recently demonstrated that the fukutin-related protein gene (FKRP) is mutated in a severe form of CMD (MDC1C), characterized by the inability to walk, leg muscle hypertrophy and a secondary deficiency of laminin alpha2 and alpha-dystroglycan. Both MDC1C and LGMD2I map to an identical region on chromosome 19q13.3. To investigate whether these are allelic disorders, we undertook mutation analysis of FKRP in 25 potential LGMD2I families, including some with a severe and early onset phenotype. Mutations were identified in individuals from 17 families. A variable reduction of alpha-dystroglycan expression was observed in the skeletal muscle biopsy of all individuals studied. In addition, several cases showed a deficiency of laminin alpha2 either by immunocytochemistry or western blotting. Unexpectedly, affected individuals from 15 families had an identical C826A (Leu276Ileu) mutation, including five that were homozygous for this change. Linkage analysis identified at least two possible haplotypes in linkage disequilibrium with this mutation. Patients with the C826A change had the clinically less severe LGMD2I phenotype, suggesting that this is a less disruptive FKRP mutation than those found in MDC1C. The spectrum of LGMD2I phenotypes ranged from infants with an early presentation and a Duchenne-like disease course including cardiomyopathy, to milder phenotypes compatible with a favourable long-term outcome.

Bilateral stimulation of globus pallidus internus for treatment of cervical dystonia

In three selected patients with severe complex cervical dystonia, continuous bilateral stimulation of the globus pallidus internus was associated with improvement of cervical dystonia, dystonia-associated pain, and functional disability.

Spectrum of SPG4 mutations in autosomal dominant spastic paraplegia

Autosomal dominant hereditary spastic paraplegia (AD-HSP) is a group of genetically heterogeneous neurodegenerative disorders characterized by pro- gressive spasticity of the lower limbs. Five AD-HSP loci have been mapped to chromosomes 14q, 2p, 15q, 8q and 12q. The SPG4 locus at 2p21-p22 has been shown to account for approximately 40% of all AD-HSP families. SPG4 encoding spastin, a putative nuclear AAA protein, has recently been identified. Here, sequence analysis of the 17 exons of SPG4 in 87 unrelated AD-HSP patients has resulted in the detection of 34 novel mutations. These SPG4 mutations are scattered along the coding region of the gene and include all types of DNA modification including missense (28%), nonsense (15%) and splice site point (26.5%) mutations as well as deletions (23%) and insertions (7.5%). The clinical analysis of the 238 mutation carriers revealed a high proportion of both asymptomatic carriers (14/238) and patients unaware of symptoms (45/238), and permitted the redefinition of this frequent form of AD-HSP.

Effect of N-acetylcysteine on plasma cysteine and glutathione following paracetamol administration

The effect of oral N-acetyl-L-cysteine (NAC) on plasma sulphhydryls has been studied in healthy volunteers. Following NAC 30 mg.kg-1, total NAC in plasma (i.e. free NAC and NAC as disulphides) reached a median peak concentration of 67 nmol.ml-1 within 45 to 60 min, and disappeared with an apparent half-life of 1.3 h. Only a fraction of total NAC (AUC 163 nmol.ml-1.h) was in the form of free NAC (AUC 12 nmol.ml-1.h, peak concentration 9 nmol.ml-1). Free cysteine was markedly increased (peak increment 49 nmol.ml-1; AUC 80 nmol.ml-1.h). Total cysteine and free and total glutathione in plasma were unchanged. Following the administration of 2 g paracetamol plasma cysteine and glutathione decreased (median decrement in AUC over 3 h was 5.1 nmol.ml-1.h and 3.8 nmol.ml-1.h, respectively). In contrast, the administration of 2 g NAC together with paracetamol resulted in an increase in the AUC of cysteine (+29.2 nmol.ml-1.h) and glutathione (+4.6 nmol.ml-1.h). The data show that NAC leads to a marked increase in circulating cysteine, in part by reacting with cystine and thereby forming mixed disulphides with cysteine and releasing free cysteine as shown in vitro. NAC had no effect on plasma glutathione in the absence of increased stress on the glutathione pools. However, NAC supports glutathione synthesis when the demand for glutathione is increased, as during the metabolism of paracetamol.

Pallidal deep brain stimulation in patients with cervical dystonia and severe cervical dyskinesias with cervical myelopathy

OBJECTIVES

Surgical treatment of complex cervical dystonia and of cervical dyskinesias associated with cervical myelopathy is challenging. In this prospective study, the long term effect of chronic pallidal stimulation in cervical dystonia and on combining the technique with spinal surgery in patients with severe cervical dyskinesias and secondary cervical myelopathy is described.

METHODS

Eight patients with a history of chronic dystonia who did not achieve adequate benefit from medical treatment or botulinum toxin injection participated in the study. Five patients had complex cervical dystonia with tonic postures and phasic movements. Three patients had rapidly progressive cervical myelopathy secondary to severe cervical dyskinesias and dystonia in the context of a generalised movement disorder. Quadripolar electrodes were implanted in the posteroventral lateral globus pallidus internus with stereotactic CT and microelectrode guidance. In the three patients with secondary cervical myelopathy, spinal surgery was performed within a few weeks and included multilevel laminectomies and a four level cervical corporectomy with spinal stabilisation.

RESULTS

Improvement of the movement disorder was noted early after pallidal surgery, but the full benefit could be appreciated only with a delay of several months during chronic stimulation. Three months after surgery, patients with cervical dystonia had improved by 38% in the severity score, by 54% in the disability score, and by 38% in the pain score of a modified version of the Toronto western spasmodic torticollis rating scale. At a mean follow up of 20 months, the severity score had improved by 63%, the disability score by 69%, and the pain score by 50% compared with preoperatively. There was also sustained amelioration of cervical dyskinesias in the three patients who underwent spinal surgery. Lead fractures occurred in two patients. The mean amplitude needed for chronic deep brain stimulation was 3.8 V at a mean pulse width of 210 micros, which is higher than that used for pallidal stimulation in Parkinson's disease.

CONCLUSIONS

Chronic pallidal stimulation is effective for complex cervical dystonia and it is a useful adjunct in patients with cervical dyskinesias and secondary cervical myelopathy who undergo spinal surgery.

Effect of botulinum toxin A injections in the treatment of chronic tension-type headache: a double-blind, placebo-controlled trial

In addition to vascular and supraspinal influences, contraction of craniofacial muscles or central sensitization processes following continuous nociceptive input of craniofacial muscles may play an important role in the pathogenesis of tension-type headache. Chemodenervation induced by botulinum toxin injection is successfully used to decrease muscle tension. If muscle tension is important in this type of headache, then botulinum toxin could be helpful in its treatment. We conducted a randomized, placebo-controlled study to examine the effect of 20 U botulinum toxin injected into frontal and temporal muscles in patients with chronic tension-type headache. During a baseline of 4 weeks and a posttreatment period of 8 weeks, the effect was evaluated with daily records and the West Haven-Yale Multidimensional Pain Inventory. Some improvement in affective variables were demonstrated in the botulinum group, but important outcome variables, such as pain intensity, the number of pain-free days, and consumption of analgesics, were not statistically different between the groups. Reasons for these moderate effects may include the injection sites, dose of botulinum toxin, and duration of treatment.

Ontogeny of expression of the corticotropin-releasing factor gene in the hypothalamic paraventricular nucleus and of the proopiomelanocortin gene in rat pituitary

The ontogeny of expression of the CRF gene in the paraventricular hypothalamic nucleus and POMC gene in the pituitary was studied in rats using in situ hybridization histochemistry and Northern blotting techniques, respectively. CRF mRNA was first detected on day 17 of gestation (E17) in the paraventricular nucleus of the hypothalamus. The levels of hypothalamic CRF mRNA increased progressively from E17 to E19-E20, decreased during the perinatal period, and increased thereafter. The levels of POMC mRNA in the pituitary paralleled the variations in hypothalamic CRF mRNA, showing a peak on E20-E21. POMC mRNA levels in the anterior pituitary were decreased on days 4-7 after birth (P4-P7) and increased steadily thereafter. In contrast to levels in the anterior pituitary, POMC mRNA levels increased steadily from P1 to P21 in the neurointermediate lobe of the pituitary. These data indicate that the expression of both the CRF and POMC genes in the paraventricular nucleus and anterior pituitary, respectively, are reduced during the first week of life, i.e. within the so-called stress nonresponsive period. Our observations suggest that an impaired regulation of ACTH and CRF synthesis due to an immature neuronal pathway within the brain or increased glucocorticoid feedback may account for the stress nonresponsive period.

Expression of neuronal nicotinic acetylcholine receptor subunit genes in the rat autonomic nervous system

In the autonomic nervous system efferent signals are relayed in sympathetic and parasympathetic ganglia. Fast synaptic transmission between pre- and postsynaptic neurons is achieved by neuronal nicotinic acetylcholine receptors (nAChRs). There is still little known about the subunit composition of these receptors. Establishing the subunit composition of native neuronal nAChRs is important for the understanding of their functional properties both in vivo and after expression in heterologous expression systems. We have combined in situ hybridization and autoradiography to detect the presence of mRNAs encoding subunits of neuronal nAChRs in sympathetic and parasympathetic ganglia. Inspection of the autoradiographs showed that the hybridization signal of five riboprobes (alpha 3, alpha 4-1, alpha 7, beta 2 and beta 4) was significantly higher than the unspecific signal obtained with sense riboprobes. The distribution of alpha 7 was tissue-dependent: alpha 7 riboprobe binding was detected in the neurons of the superior cervical ganglion, adrenal medulla and ciliary ganglion. In contrast, the alpha 7 hybridization signal was found only in a small fraction (1-3%) of the neurons of the sphenopalatine and otic ganglia. Our results are consistent with the idea that alpha 3 mRNA expression levels are somewhat higher than those of alpha 7, alpha 4-1, beta 2 and beta 4.

The distribution of thalamic projection neurons containing cholecystokinin messenger RNA, using in situ hybridization histochemistry and retrograde labeling

The distribution of cholecystokinin (CCK) synthesizing neurons in the thalamus was studied using in situ hybridization histochemistry. The message coding for CCK is present at different levels of intensity in almost all neurons (95%) of the anterior, ventral, medial and lateral groups of nuclei, with the ventral nuclei having the highest grain density. Many neurons (90%) of the medial and dorsal lateral geniculate nuclei also contained high levels of CCK transcripts. Very few neurons were found to express CCK in the parafascicular and paraventricular nuclei (2% and 10%, respectively), whereas the other intralaminar and midline nuclei had intermediate levels of CCK transcripts (75% of the neurons). The ventral lateral geniculate nucleus and the reticular nucleus were completely devoid of signal. After injection of the fluorescent dye, Fluorogold, into several areas of the cortex and corpus striatum, almost all retrogradely labeled cells in the thalamus (except in the parafascicular nucleus) expressed the CCK gene.

Long-term follow-up study of chronic globus pallidus internus stimulation for posttraumatic hemidystonia

The authors report the first case of chronic globus pallidus internus (GPi) stimulation for treatment of medically intractable hemidystonia for which long-term follow-up data are available. The patient had developed left-sided low-frequency tremor and hemidystonia after a severe head trauma sustained at 15 years of age. He experienced relief of the tremor but not of the hemidystonia after a thalamotomy was performed in the right hemisphere 3 years postinjury. When the patient was 24 years old, the authors performed a magnetic resonance-guided stereotactic implantation of a monopolar electrode in the right-sided posteroventral GPi. Chronic deep brain stimulation resulted in remarkable improvement of dystonia-associated pain, phasic dystonic movements, and dystonic posture, which was accompanied by functional gain. Postoperative improvement was sustained after 4 years of follow up. Chronic GPi stimulation appears to be a valuable treatment option for posttraumatic dystonia.

Effect of chronic pallidal deep brain stimulation on off period dystonia and sensory symptoms in advanced Parkinson's disease

OBJECTIVE

To investigate the efficacy of chronic pallidal deep brain stimulation (DBS) on off period dystonia, cramps, and sensory symptoms in advanced Parkinson's disease (PD).

METHODS

16 patients (6 women, 10 men; mean age at surgery 65 years) suffering from advanced PD were followed up prospectively for one year after implantation of a monopolar electrode in the posteroventral lateral globus pallidus internus. Unilateral DBS was performed in 9 patients. 10 patients had bilateral procedures (contemporaneous bilateral surgery in 7 and staged bilateral surgery in 3 instances). The decision whether to perform unilateral or bilateral surgery depended on the clinical presentation of the patient. Patients were formally assessed preoperatively, at 3-5 days, 3 months, and 12 months after surgery.

RESULTS

In patients who underwent unilateral surgery, pain was present in 7 (78%), off dystonia in 5 (56%), cramps in 6 (67%), and dysaesthesia in 4 (44%). In patients who underwent bilateral surgery, pain was present in 7 (70%), off dystonia in 6 (60%), cramps in 7 (70%), and dysaesthesia in 4 (40%). With unilateral DBS, contralateral off period dystonia was improved by 100% at 1 year postoperatively, pain by 74%, cramps by 88%, and dysaesthesia by 100%. There was less pronounced amelioration of ipsilateral off period dystonia and sensory symptoms. With bilateral DBS, total scores for dystonia were improved by 86%, for pain by 90%, for cramps by 90%, and for dysaesthesia by 88%. The benefit appeared early at the first evaluation 3-5 days after surgery and was stable throughout the follow up period.

CONCLUSIONS

Pallidal DBS yields major improvement of off period dystonia, cramps, and sensory symptoms in patients with advanced PD.

Cortical neurons expressing the cholecystokinin gene in the rat: distribution in the adult brain, ontogeny, and some of their projections

Recent studies of neuronal cholecystokinin (CCK) expression performed with more sensitive techniques have demonstrated that the distribution of the expression of this peptide is more widespread than previously thought. In the present study, hybridization histochemistry was used to map cortical neurons expressing the CCK gene in adult and developing rats. Retrograde tracing with Fluorogold in combination with hybridization histochemistry was used to demonstrate some of the projections of these neurons. Neurons expressing the CCK gene were found in all areas of the neo- and allocortices. They were of several morphological types, including pyramidal neurons, and were found in almost all layers, albeit at different relative numbers and with different levels of expression. Generally, layers II and III, deep layer V, and layer VI had many neurons expressing CCK mRNA. Cortical CCK expression was first detected on the 15th day of gestation in the primordial plexiform layer. Expression developed thereafter in a regular and continuous fashion until an adult-like pattern was present on the 21st day after birth. Cortical neurons containing CCK mRNA were found in almost all the projections studied. Many neurons in both neo- and allocortical areas with cortico-cortical, associational, and commissural pathways contained CCK mRNA. Similarly, numerous corticostriatal neurons contained CCK mRNA; however, only a few corticothalamic neurons expressed CCK mRNA. These results demonstrate that in the rat cortex the distribution of projection neurons expressing CCK is much more widespread than had been previously shown and will stimulate further investigations into the role of CCK in these neurons.

Circadian patterns of neurotransmitter related gene expression in motor regions of the rat brain

Mammalian motor activity displays circadian patterns in normal behaviour and in many movement disorders, like levodopa responsive dystonia and Parkinson's disease. Here, we hypothesized that a circadian pattern of dopamine synthesis would trigger rhythms in the expression of genes in regions receiving dopaminergic innervation. Indeed tyrosine hydroxylase and cholecystokinin mRNA were upregulated in the substantia nigra and ventral tegmental area in the course of the day. However, in the caudate putamen, the mRNA levels, for dopamine D2 and adenosine 2A receptor, dynorphin, and substance P were lower during the day than during the night, whereas the expression of dopamine D1 receptor, enkephalin, and somatostatin was stable. In the frontal cortex, a clear midday peak of enkephalin expression was detected, while cholecystokinin and vasoactive intestinal peptide expression did not vary. Clear circadian gene expression patterns can therefore be demonstrated in brain regions involved in motor regulation, but they do not follow a simple dopaminergic drive and more complex regulatory patterns have to be assumed.

EFNS/ENS Consensus on the diagnosis and management of chronic ataxias in adulthood

BACKGROUND AND OBJECTIVES

The ataxias are a challenging group of neurological diseases due the aetiological heterogeneity and the complexity of the genetic subtypes. This guideline focuses on the heredodegenerative ataxias. The aim is to provide a peer-reviewed evidence-based guideline for clinical neurologists and other specialist physicians responsible for the care of patients with ataxia.

METHODS

This guideline is based on systematic evaluations of the relevant literature and on three consensus meetings of the task force.

DIAGNOSIS

If acquired causes are ruled out, and if the disease course is rather slowly progressive, a (heredo)degenerative disease is likely. A positive family history gives much guidance. In the case of a dominant family history, first line genetic screening is recommended for spinocerebellar ataxia (SCA) 1, 2, 3, 6, 7 and 17 (level B), and in Asian patients also for dentatorubral-pallidoluysian atrophy (DRPLA). In the case of recessive disease, a stepwise diagnostic work-up is recommended, including both biochemical markers and targeted genetic testing, particularly aimed at Friedreich's ataxia, ataxia telangiectasia, ataxia due to vitamin E deficiency, polymerase gamma gene (POLG gene, various mutations), autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) and ataxia with oculomotor apraxia (AOA) types 1 and 2. If family history is negative, we still advise to screen for the more common dominant and recessive ataxias. In addition, if onset is below 45 years we recommend the full work-up for recessive ataxias; if onset is above 45 years we recommend to screen for fragile X mental retardation 1 FMR1 premutations (good practice points). In sporadic cases with an onset after 30 years, a diagnosis of multiple system atrophy should be considered (good practice point). In particular the genetic work-up will change over the upcoming years due to the diagnostic utility of new techniques such as gene panel diagnostics based on next generation sequencing for routine work-up, or even whole exome and genome sequencing for selected cases.

TREATMENT

Some of the rare recessive ataxias are treatable, but for most of the heredodegenerative ataxias treatment is purely symptomatic. Idebenone is not effective in Friedreich's ataxia (level A). Riluzole (level B) and amantadine (level C) might provide symptomatic relief, irrespective of exact etiology. Also, varenicline for SCA3 patients (level B) can be considered. There is level Class II evidence to recommend physiotherapy, and Class III data to support occupational therapy.

Concepts and methods in chronic thalamic stimulation for treatment of tremor: technique and application

OBJECTIVE

To rationalize the technique and reduce the costs associated with chronic deep brain stimulation of the thalamus for treatment of refractory tremor.

METHODS

The efficacy and safety of a modification in surgical techniques was prospectively assessed in 94 patients with tremor. Bilateral electrodes were implanted in 29 patients, and 65 patients received unilateral implants. Forty-five patients had Parkinson's disease tremor, 42 patients had essential tremor, and 7 patients had kinetic tremors of different causes. In all instances, intraoperative stimulations to analyze the thresholds of intrinsic and extrinsic responses were performed directly with the implanted leads. The electrodes were repositioned until satisfactory results were achieved. The pulse generators were implanted directly after the first step in the same operative session. Patients were not subjected to interoperative test stimulation trials.

RESULTS

Postoperative improvement of tremor at a mean follow-up of 11.9 months was rated as excellent in 47 patients (50%), marked in 37 patients (39%), moderate in 8 patients (9%), and minor in 2 patients (2%). There was no persistent morbidity related to surgery. In patients with Parkinson's disease, the symptomatic improvement of tremor was rated as excellent in 51% of patients, marked in 36%, moderate in 11%, and minor in 2%. In patients with essential tremor, symptomatic outcome was classified as excellent in 57% of patients, marked in 36%, moderate in 5%, and minor in 2%. Six of the seven patients with kinetic tremor achieved marked symptomatic improvement, and one patient experienced moderate improvement. Forty patients experienced stimulation-related side effects. Side effects were mild in general, and they were reversible with a change in electrical parameters. They occurred more frequently in patients who had bilateral stimulation.

CONCLUSION

Excellent to marked improvement of tremor is achieved in the majority of patients with physiological target determination via implanted leads in thalamic deep brain stimulation. Interoperative test stimulation trials are unnecessary. Modifications in technique may help to reduce the costs of the related hospital stay.

Decreased production of glutathione in patients with cirrhosis

Studies in animals have demonstrated the central role of the liver in regulating the circulating pool of glutathione (GSH). Most of the hepatic GSH production is released into blood and most of the circulating GSH originates in the liver. We have estimated the production of GSH in eight healthy volunteers and eight patients with cirrhosis by an analysis of the kinetics of plasma GSH. The basal plasma concentrations of free GSH were 9.3 +/- 2.4 microM in healthy volunteers and 3.6 +/- 1.1 microM in cirrhotics (P less than 0.001), and the concentrations of total GSH 16.6 +/- 6.2 microM in control subjects and 7.1 +/- 2.6 microM in cirrhotics (P less than 0.002). The concentration of GSH in the circulating pool depends on the input of GSH into this compartment and is inversely proportional to the volume of distribution of GSH (Vd) and to the fractional rate of elimination of GSH from plasma (kel). Assuming that the kinetics of endogenously produced and exogenously administered GSH are identical, Vd and kel can be calculated from the plasma concentration-time curve of a single i.v. injection of GSH. Both Vd (0.100 +/- 0.044 l kg-1 in controls and 0.131 +/- 0.043 l kg-1 in cirrhotics) and kel (0.2718 +/- 0.0555 min-1 in controls and 0.2912 +/- 0.0781 min-1 in cirrhotics) were identical in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabotropic glutamate receptor 2/3 in the hippocampus of patients with mesial temporal lobe epilepsy, and of rats and mice after pilocarpine-induced status epilepticus

A comparative study of the expression of metabotropic glutamate receptor 2/3 (mGluR2/3) was done in the hippocampus of rats and mice after pilocarpine-induced status epilepticus (APISE), and of patients with mesial temporal lobe epilepsy. At 1 day APISE, there was a marked increase in mGluR2/3 immunoreactivity in the stratum lacunosum moleculare (SLM) of CA1 area and in the middle one-third of the molecular layer (MM) of the dentate gyrus. Immuno-electron microscopic study showed degenerating mGluR2/3 positive axons in the SLM of CA1 area at 1 day APISE. From 7 days, mGluR2/3 immunopositive product decreased, and by 31 days APISE, it almost disappeared in two-thirds of the SLM near CA2. In the mouse model at 2 months APISE, mGluR2/3 immunopositive product in two-thirds of the SLM near the stratum radiatum disappeared, and so did in the whole SLM of CA1 area in patients with mesial temporal lobe epilepsy. Neuropharmacological study by intravenous injection of mGluR2/3 agonist 2R,4R-4-aminopyrrolidine-2,4-dicarboxylate [(2R,4R)-APDC] at different doses at 1h during pilocarpine induced status epilepticus showed that (2R,4R)-APDC could not stop seizures and neuronal death in the hilus of the dentate gyrus. The present study, therefore, suggests that the reduction of mGluR2/3 immunopositive product in the SLM of CA1 is a consequence of neuronal loss in either the entorhinal cortex or CA1 area of the hippocampus, and at the dosage range from 12.5 to 600 mg/kg, (2R,4R)-APDC may not be effective in the prevention of seizures or neuronal death in the hilus of the dentate gyrus.

Expression of adenosine A2a receptors gene in the olfactory bulb and spinal cord of rat and mouse

The expression of adenosine A2a receptors (A2aR) in the mammalian striatum is well known. In contrast the exact distribution of A2aR in other regions of the central nervous system remains unclear. The aim of this study was to investigate the A2aR gene expression in the rat olfactory bulb and spinal cord, two regions which are seldom included in mapping studies. Secondly, we compared the A2aR expression in the rat and in the mouse brain. Hybridization histochemistry was performed with an S35-labelled radioactive oligonucleotide probe. The results show strong expression of A2aR in the mouse and rat striatum in accordance with previous reports. In the olfactory bulb a weak but specific expression of A2aR was found in the granular cell layer in both species. In contrast, no significant expression of the A2aR gene was observed in other parts of the brain or the rat spinal cord. The presence of the A2aR in the mammalian olfactory bulb suggests a functional role for this receptor in olfaction.

Phenotype of autosomal dominant spastic paraplegia linked to chromosome 2

We report the clinical features of 12 families with autosomal dominant spastic paraplegia (ADSP) linked to the SPG4 locus on chromosome 2p, the major locus for this disorder that accounts for approximately 40% of the families. Among 93 gene carriers, 32 (34%) were unaware of symptoms but were clinically affected. Haplotype reconstruction showed that 90% of the asymptomatic gene carriers presented increased reflexes and/or extensor plantar responses independent of age at examination. The mean age at onset was 29 years, ranging from 1 to 63 years. Intra- as well as inter-familial variability of age at onset was important, but did not result from anticipation. Phenotype-genotype correlations and comparison with SPG3 and SPG5 families indicated that despite the variability of age at onset, SPG4 is a single genetic entity but no clinical features distinguish individual SPG4 patients from those with SPG3 or SPG5 mutations.

Distribution, projection and dopaminergic regulation of the neurokinin B mRNA-containing neurons of the rat caudate-putamen

Neurons containing transcripts encoding neurokinin B, a member of the tachykinin family, were studied in the rat caudate-putamen using hybridization histochemistry. Neurons containing neurokinin B mRNA were distributed throughout the caudate-putamen, with a slightly higher density in the middle portions as compared with the more rostral and caudal portions. These neurons were either isolated, often located close to neurons devoid of neurokinin B mRNA, or in small clusters of three to 10 cells. A larger group of neurons with neurokinin B mRNA was seen in the ventrolateral caudate-putamen, near the tip of the external capsule. Neurokinin B mRNA was colocalized in neurons with substance P (59% of neurokinin B neurons had substance P mRNA) and with enkephalin mRNA (25% of neurokinin B neurons had enkephalin mRNA). After injections of the fluorescent dye Fluorogold into the globus pallidus and substantia nigra, retrograde axonal transport studies demonstrated neurokinin B mRNA in striatopallidal but not striatonigral projections. The influence of dopaminergic input on the level of neurokinin B mRNA in the caudate-putamen was studied after 6-hydroxydopamine lesions of the substantia nigra/ventral tegmental area. Both the number of cells detected containing neurokinin B mRNA as well as the level of transcripts per cell increased on the side ipsilateral to the lesion, whereas the opposite was seen on the contralateral side. These results describe a novel neurochemical system within the rat basal ganglia that is regulated by dopaminergic innervation from the mesencephalon.

Chronic thalamic stimulation for treatment of dystonic paroxysmal nonkinesigenic dyskinesia

The authors report the effect of chronic stimulation of the ventrointermediate (Vim) thalamus for treatment of dystonic paroxysmal nonkinesigenic dyskinesias (PNKD). A 37-year-old patient had a 4-year history of severe and painful PNKD of the right arm. Chronic stimulation through a stereotactically implanted monopolar electrode in the left Vim resulted in a decrease of the frequency, duration, and intensity of the dystonic paroxysmal movement disorder. The benefit of stimulation has been maintained over 4 years of follow-up.

EFNS guidelines on the molecular diagnosis of neurogenetic disorders: general issues, Huntington's disease, Parkinson's disease and dystonias

BACKGROUND AND PURPOSE

These EFNS guidelines on the molecular diagnosis of neurogenetic disorders are designed to provide practical help for the general neurologist to make appropriate use of molecular genetics in diagnosing neurogenetic disorders. Since the publication of the first two EFNS-guideline papers on the molecular diagnosis of neurological diseases in 2001, rapid progress has been made in this field, necessitating an updated series of guidelines.

METHODS

Literature searches were performed before expert members of the task force wrote proposals, which were discussed in detail until final consensus had been reached among all task force members.

RESULTS AND CONCLUSION

This paper provides updated guidelines for molecular diagnosis of Huntington's disease, Parkinson's disease and dystonias as well as a general introduction to the topic. Possibilities and limitations of molecular genetic diagnosis of these disorders are evaluated and recommendations are provided.

Onset of glucocorticoid responsiveness of anterior pituitary corticotrophs during development is scheduled by corticotropin-releasing factor

Expression of the CRF gene in the hypothalamus and that of the POMC gene in the anterior pituitary are reduced during the first week of life in the rat. During this so-called stress nonresponsive period (SNRP), stimuli such as ether vapors, electroshocks, and hypoxia do not elicit ACTH secretion from the pituitary, as occurs later in development. The current hypothesis to explain the SNRP is an increased negative glucocorticoid feedback on POMC and CRF synthesis and/or release during this time. To test this hypothesis we studied the effects of adrenalectomy (ADX) on anterior pituitary POMC mRNA expression. In 7-day-old rats POMC mRNA levels were increased only 3-fold 48 h post-ADX, compared to a 7-fold increase in 14-day-old animals. This blunted effect of endogenous glucocorticoid removal on pituitary POMC mRNA could be due to decreased up-regulation of CRF after removal of glucocorticoids or normal up-regulation of CRF but decreased pituitary responsiveness to CRF relative to those in 14-day-old animals. Therefore, we studied in vitro beta-endorphin release from pituitaries obtained from 7- and 14-day-old rats. CRF stimulated basal beta-endorphin release to the same extent in pituitaries from both groups. The inhibition by corticosterone of CRF-stimulated beta-endorphin secretion was also indistinguishable in pituitaries obtained from 7- or 14-day-old rats. Since the responsiveness of the 7-day-old pituitary was normal, the blunted enhancement of POMC biosynthesis after ADX must be mediated at the level of the hypothalamus. Indeed, in situ hybridization showed that while in 14-day-old rats ADX induced a significant increase [190 +/- 10% (+/- SE) of control; n = 5; P less than 0.0005] in hypothalamic mRNA levels, ADX did not change the expression of the CRF gene in the paraventricular nucleus of 7-day-old rats, indicating a lack of glucocorticoid modulation of hypothalamic CRF synthesis. Finally, we studied the effects of 48 h CRF treatment on the post-ADX increase in POMC mRNA levels in 7-day-old rats. Daily injections of 200 ng CRF/rat induced an increase in anterior pituitary POMC mRNA concentrations [669 +/- 139% (+/- SE) of control; n = 6; P less than 0.02 vs. adrenalectomized vehicle-treated rats] comparable to that in adrenalectomized untreated 14-day-old rats. In conclusion, our data indicate that the glucocorticoid regulation of hypothalamic CRF gene expression is not mature during the first week of life, i.e. within the so-called SNRP.(ABSTRACT TRUNCATED AT 400 WORDS)

EFNS guidelines on the molecular diagnosis of ataxias and spastic paraplegias

BACKGROUND AND PURPOSE

These EFNS guidelines on the molecular diagnosis of neurogenetic disorders are designed to provide practical help for the general neurologist to make appropriate use of molecular genetics in diagnosing neurogenetic disorders.

METHODS

Literature searches were performed before expert members of the task force wrote proposals, which were discussed in detail until final consensus had been reached among all task force members.

RESULTS AND CONCLUSION

This paper provides updated guidelines for molecular diagnosis of two particularly complex groups of disorders, the ataxias and spastic paraplegias. Possibilities and limitations of molecular genetic diagnosis of these disorders are evaluated and recommendations are provided.