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Biomedical subjects

D Devos

Publications and source records attributed to D Devos.

8 recordsLinked to original sources
PubMed2001

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↗
PubMed2000

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↗
PubMed2000

[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↗
PubMed2000

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↗
PubMed1998

[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↗
PubMed1997

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↗