Alpha-fodrin autoantibodies in the differential diagnosis of MS and Sjögren syndrome.
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Adult↗
Biomedical subjects
D Devos
Publications and source records attributed to D Devos.
Heart rate variability and Parkinson's disease severity.
Heart rate variability (HRV) decrease in Parkinson's disease (PD) could only be a consequence of reduce motor activity besides of being a marker of cardiovascular dysautonomia. Under continuously recorded and standardised motor activity, we studied thirty patients compared to controls in 3 PD stages: group I: less than 2 year-evolution, slight impaired without L-dopa; group II: mildly impaired with L-dopa; group III: advanced PD with motor complications. No difference was observed between group I and controls. The diurnal low frequency power (LF) and the ratio of LF/high frequency (HF) power decreased in groups II and III. The nocturnal vagal indicators: HF power and pNN50 were decreased in group III. Those parameters were correlated with Off-drug-motor handicap, suggesting an evolutive HRV decrease with disease severity but not with On-drug-motor activity. The low LF despite the higher motor activity in group III, due to dyskinesias, suggested a defective cardiovascular up-regulation.
Autonomic Nervous System Diseases↗
Prediction of human protein function from post-translational modifications and localization features.
We have developed an entirely sequence-based method that identifies and integrates relevant features that can be used to assign proteins of unknown function to functional classes, and enzyme categories for enzymes. We show that strategies for the elucidation of protein function may benefit from a number of functional attributes that are more directly related to the linear sequence of amino acids, and hence easier to predict, than protein structure. These attributes include features associated with post-translational modifications and protein sorting, but also much simpler aspects such as the length, isoelectric point and composition of the polypeptide chain.
Computational Biology↗
Influence of internal globus pallidus stimulation on motor cortex activation pattern in Parkinson's disease.
OBJECTIVES: Indications of the functional neurosurgical treatments become more and more numerous, however, few methods were used to study the mechanism of action and some discrepancies came to light. We assessed the influence of internal globus pallidus (GPI) stimulation and L-Dopa on cortical activation during the preparation and execution phases of the movement compared to clinical improvement of Parkinson's disease. METHODS: We recorded the movement-related cortical potential and movement-related desynchronization. RESULTS: The Unified Parkinson's Disease Rating Scale was improved by 46% under stimulation and 64% under stimulation with L-Dopa. Premovement desynchronization was significantly increased on central contralateral derivation under stimulation with L-Dopa and decreased on frontocentral ipsilateral derivation under stimulation with and without L-Dopa. Movement desynchronization was improved on the contralateral motor cortex under stimulation with and without L-Dopa (benefit correlated with bradykinesia improvement). The movement-related postmotor potential was significantly increased under stimulation with L-Dopa. CONCLUSIONS: GPI stimulation alone influenced the premotor cortex activation during the planning and induced a selective and focal effect on the organisation of motor cortical activity during the movement execution which may explain bradykinesia improvement. The motor cortex activation improvement under stimulation with L-Dopa concerned both the movement preparation and execution but remained very localised to the contralateral motor cortex.
Aged↗
Deciphering the action of aromatic effectors on the prokaryotic enhancer-binding protein XylR: a structural model of its N-terminal domain.
The prokaryotic enhancer-binding protein XylR is the central regulator of the toluene degradation pathway in Pseudomonas species. Copious genetic and biochemical data indicate that the N-terminal domain of the protein (domain A) interacts directly with m-xylene, which renders the protein competent as a transcriptional activator. Single-site and shuffling mutants of XylR or homologues have been reported to change or expand their effector profiles. Here, we follow a fold recognition approach to generate three-dimensional models of the domain A of XylR and DmpR with the purpose of deciphering the molecular activity of this protein family. The model is based on the crystallographic data of the rat catechol O-methyltransferase, a typical alpha/beta fold, consisting of eight alpha-helices and seven beta-strands. The fold identification is supported by physico-chemical properties of conserved amino acids, distribution of residues characteristic of the sequence families and confrontation with experimental data. The model not only provides a rationale for understanding published experimental data, but also suggests the molecular mechanism of the activation step and is a potentially useful conceptual tool for designing regulators with predefined inducer specificities.
Amino Acid Sequence↗
[Acute rhombencephalitis with fever and bilateral hearing loss secondary to Gougerot-Sjögren's syndrome].
The usual polymorphic central nervous system involvement observed in primary Sjögren's syndrome is classified as monofocal, multifocal or diffuse involvement. We present a case of acute rhombencephalitis associated with hearing loss that could correspond to an intermediate form between diffuse and monofocal involvement. The acute onset with fever and not clinical sign of xerostomia or xerophthalmia suggest the possibility of vascular-like or infectious-like forms. We emphasize the importance of obtaining a minor salivary gland biopsy for diagnosis of Sjögren's syndrome and suggest that Sjögren's syndrome could be frequently misdiagnosed.
Abducens Nerve Diseases↗
The prevalence of Sjögren syndrome in patients with primary progressive multiple sclerosis.
OBJECTIVE: To assess the prevalence of Sjögren syndrome (SS) in patients with primary progressive MS (PPMS). BACKGROUND: SS may be considered in the differential diagnosis of MS. Age at onset and clinical presentation are similar in SS and PPMS. However, occurrence of SS in definite cases of PPMS has been recently reported. METHODS: Proposed clinical and laboratory diagnostic criteria for SS were systematically assessed in 60 consecutive patients with PPMS. The authors questioned all patients about xerophthalmia and xerostomia, biopsied minor salivary glands, and performed a Schirmer test, a salivary gland scintigraphy, and anti-Ro (SSa) and anti-La (SSb) serologies. RESULTS: Ten patients (16.6%) met four or more criteria for SS. This prevalence is higher than in the general population (1 to 5%) and implies that SS can mimic PPMS. CONCLUSIONS: The authors propose that SS should be screened for systematically in patients with PPMS.
Adult↗
Clinical features and genetic analysis of a new form of spinocerebellar ataxia.
BACKGROUND: The autosomal dominant cerebellar ataxias (ADCA) are a clinically heterogeneous group of disorders. The mutations for SCA1, SCA2, SCA3, SCA6, SCA7, SCA8, and SCA-12 are identified and caused by an expansion of a CAG or a CTG repeat sequence of these genes. Six additional loci for SCA4, SCA5, SCA-10, SCA-11, SCA-13, and SCA-14 are mapped. The growing heterogeneity of the autosomal dominant forms of these diseases shows that the genetic etiologies of at least 20% of ADCA have yet to be elucidated. METHODS: The authors ascertained and clinically characterized a four-generation pedigree segregating an autosomal dominant phenotype for SCA. Direct mutation analysis, repeat expansion detection analysis, and linkage analysis for all known SCA loci were performed. RESULTS: Direct mutational analysis excluded SCA1, 2, 3, 6, 7, 8, and 12; genetic linkage analysis excluded SCA4, 5,10, 11, 13, and 14, giving significant negative lod scores. Examination of the family showed that all affected members had gait ataxia and akinesia with variable features of dysarthria, hyporeflexia, and mild intellectual impairment. Eye movements were normal. Head MRI showed atrophy of the cerebellum without involvement of the brainstem. In 10 parent-child pairs, median onset occurred 10.5 years earlier in offspring than in their parents, suggesting anticipation. CONCLUSION: This family is distinct from other families with SCA and is characterized by cerebellar ataxia and extrapyramidal signs.
Adult↗
Silver stained isoelectrophoresis of tears and cerebrospinal fluid in multiple sclerosis.
Cerebrospinal fluid (CSF) analysis aids in the diagnosis of multiple sclerosis. However, this examination is invasive. The aim of this study was to assess the potentials of a new method of tears isoelectrophoresis (IEF). Silver staining of IEF was used to examined tears and CSF from 123 patients including 60 patients with multiple sclerosis (MS), 50 other neurological patients and 13 patients with inflammatory neurological diseases. Tears were collected on a Shirmer strip placed in one eye, avoiding reflex secretion. This method of IEF with silver staining allowed the detection of oligoclonal bands in tears that were truly immunoglobulin G on immunofixation. The concordance rate between tears and CSF was 83%, meaning that CSF provided no more information than tears analysis in 83% of cases. Sensitivity in tears (72%) and CSF (75%) was very close as was specificity (respectively 84 % and 86 %). High concordance between tears and CSF is the first step in developing a non invasive test which could replace lumbar puncture, particularly when this procedure is not fearalele or is refused by the patient.
Adolescent↗
Autonomic dysfunction in multiple sclerosis: cervical spinal cord atrophy correlates.
Autonomic dysfunction has rarely been studied in patients suffering from multiple sclerosis (MS). Some hypotheses have concerned the pathophysiology, especially with regard to a possible spinal cord origin. However, there have been no previous studies on autonomic dysfunction in MS and spinal cord lesions. This study assessed the frequency of autonomic dysfunction (AD) in MS and the correlation to spinal cord magnetic resonance imaging (MRI) findings. We prospectively studied 75 MS patients (25 with relapsing-remitting forms, 25 with secondary progressive forms and 25 with primary progressive forms). We performed sympathetic skin response, R-R interval variability and orthostatic hypotension testing. Spinal cord MRI was performed to detect demyelinating lesions (sagittal and axial plane) or spinal cord atrophy. Clinical and laboratory evidence of AD was found in 84% and 56% of MS patients, respectively. The correlation of the latter with disability was evaluated using the Extended Disability Status Scale. AD was more frequent in primary progressive MS than in the other two forms. AD was correlated with spinal cord cross-sectional area reduction but not with spinal cord hyperintensities. This study confirms that the frequency of AD in MS, especially in primary progressive forms, has until now been underestimated. Furthermore, AD appears to be more closely related to axonal loss, as demonstrated by spinal cord atrophy, than to demyelinating lesions.
Adult↗
Intrinsic errors in genome annotation.
Genome sequencing is usually followed by routine annotation of protein function based on the assumption that similar sequences will have similar functions. Here, we introduce a simple calculation to estimate the magnitude of any possible annotation errors. We counted the number of discrepancies in the annotation of well-established sets of similar proteins and extrapolated these values to the pairs of similar sequences used for the annotation of different microbial genomes. We conclude that the number of potential errors in the prediction of detailed functions is higher than is usually believed.
Binding Sites↗
A la carte transcriptional regulators: unlocking responses of the prokaryotic enhancer-binding protein XylR to non-natural effectors.
To investigate the activation mechanism of the enhancer-binding protein XylR encoded by the TOL plasmid of Pseudomonas putida mt-2, a combinatorial library was generated composed of shuffled N-terminal A domains of the homologous regulators DmpR, XylR and TbuT, reassembled within the XylR structure. When the library was screened in vivo for responsiveness to non-effectors bulkier than one aromatic ring (such as biphenyl) or bearing an entirely different distribution of electronegative groups (e.g. nitrotoluenes), protein variants were found that displayed an expanded inducer range including the new effectors. Although the phenotypes endowed with the corresponding changes were largely similar, the modifications involved different sites within the A domain. The positions of the mutations within a structural model of the A domain suggest that expansion of the inducer profile can be brought about not only by changes in the effector pocket of the protein but also by unlocking steps of the signal transmission mechanism that follows effector binding. These results provide a rationale for evolving in vitro regulators à la carte that are responsive to predetermined, natural or xenobiotic chemical species.
Bacterial Proteins↗
Practical limits of function prediction.
The widening gap between known protein sequences and their functions has led to the practice of assigning a potential function to a protein on the basis of sequence similarity to proteins whose function has been experimentally investigated. We present here a critical view of the theoretical and practical bases for this approach. The results obtained by analyzing a significant number of true sequence similarities, derived directly from structural alignments, point to the complexity of function prediction. Different aspects of protein function, including (i) enzymatic function classification, (ii) functional annotations in the form of key words, (iii) classes of cellular function, and (iv) conservation of binding sites can only be reliably transferred between similar sequences to a modest degree. The reason for this difficulty is a combination of the unavoidable database inaccuracies and the plasticity of protein function. In addition, analysis of the relationship between sequence and functional descriptions defines an empirical limit for pairwise-based functional annotations, namely, the three first digits of the six numbers used as descriptors of protein folds in the FSSP database can be predicted at an average level as low as 7.5% sequence identity, two of the four EC digits at 15% identity, half of the SWISS-PROT key words related to protein function would require 20% identity, and the prediction of half of the residues in the binding site can be made at the 30% sequence identity level.
Amino Acid Sequence↗
Choreic movements induced by cibenzoline: an Ic class antiarrhythmic effect?
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Aged↗
[Thulium laser evoked potentials. Normative values for the arms and legs].
Laser somatosensory evoked potentials (LSEP) evaluate the functional integrity of thermoalgic pathways by the specific stimulation of A delta and C nociceptive afferences. As compared to a CO2 laser, the thulium Yttrium Aluminium Garnet (YAG) laser may be conducted by an optic fiber, which allows easier access to the stimulated body sites. We present normative data on thulium YAG LSEPs recorded after stimulation of upper and lower limbs (N = 15). LSEPs were obtained with a stimulation intensity that was twice the nociceptive threshold at the upper limbs (UL) and one and a half at the lower limbs (LL). To ensure a stable attentional level, subjects were asked to estimate stimulus intensity after each stimulation. The nociceptive thresholds at upper and lower limbs were respectively 319 +/- 65 mJ and 359 +/- 95, and with the above methodology the LSEPs could be obtained in every subject. The latencies of N2 and P2 were respectively 199 +/- 18 ms and 325 +/- 37 ms at the UL, 239 +/- 36 ms and 378 +/- 38 ms at the LL. This method produced robust and reproducible results and proved to be reliable for routine clinical use. To optimise response stability we propose that right/left stimulation be conducted following an 'A-B-B-A' procedure.
Adult↗
Brief and sustained movements: differences in event-related (de)synchronization (ERD/ERS) patterns.
OBJECTIVE: (1) To determine if there are changes in event-related desynchronization/event-related synchronization (ERD/ERS) patterns when the movement is sustained? (2) To determine, from a technical point of view for ERD calculation, if it is possible to take the reference period during muscular activation? METHODS: Eight healthy subjects performed two series of brief and sustained self-paced extensions with their dominant wrist. The end of the sustained movement was externally triggered by the examinator. ERD/ERS was calculated in mu and beta bands from 13 source derivations covering motor areas, computed from 29 scalp electrodes. Movement onset and offset were determined by electromyographic activity (EMG) of wrist extensors. RESULTS: When the movement was sustained, power in the mu and beta bands returned to baseline values within 4-5 s. Movement duration had little effect, if at all, on both pre and post-movement periods. Compared to brief movement, after the onset of the prolonged movement, mu ERD just returned to baseline, without synchronization. In contrast, beta ERS was still present though earlier and much lower. CONCLUSIONS: The reference period for ERD calculation may be taken during muscular activation if its duration is long enough. Beta synchronization may occur despite a non-deactivated motor cortex, suggesting a contribution from afferent somesthetic inputs.
Cortical Synchronization↗
[Traumatic bilateral paralysis of the abducens nerve without cervical fracture].
We report the case of a 75-year-old woman with an uneventful medical history who presented with sudden-onset diplopia immediately after neck trauma in a traffic accident. Clinical and ophthalmological examinations were consistent with bilateral abducens nerve palsy. The causal relationship, including the medicolegal implications and the pathophysiological mechanism are discussed. The case demonstrates that exceptionally benign trauma can cause severe diplopia. The delay to recovery may be very long, suggesting caution concerning the decision of surgical care.
Abducens Nerve Injury↗
ANOLEA: a www server to assess protein structures.
ANOLEA (Atomic Non-Local Environment Assessment) is a www server that performs energy calculations at the atomic level in protein structures. The calculations involve the non-local interactions between all the heavy atoms of the twenty standard amino acids in the molecule. The input of the server is a PDB file containing one or more protein chains. The output is an energy profile, which gives an energy value for each amino acid of the protein. High energy zones (HEZs) in the profile correlate with errors or with potential interacting zones of proteins. The output of the server also displays the structure in three dimensions, pointing out the high energy amino acids in the protein. This option requires the CHIME plug-in, which is freely available on Internet and makes possible, in real time, to rotate, translate and change the point of view and presentation of the molecule in three dimensions. Thus, a fast analysis of a protein structure can be done using a personal computer connected to Internet. The server is available at: http:@www.fundp.ac.be/pub/ANOLEA.html.
Amino Acids↗