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Biomedical subjects

C Bonnard

Publications and source records attributed to C Bonnard.

At least 19 recordsLinked to original sources

[Neurofibromatosis type 1 complications in the pediatric age: follow-up of a hundred cases].

UNLABELLED: Neurofibromatosis 1 (NF1) is a frequent genetic disease. Diagnostic criterias were established in 1988. The patients can exhibit various and unpredictable complications. OBJECTIVES: To check the efficiency of a coordinated follow-up in specialized multidisciplinary centers providing a higher quality of management and to have a better knowledge of the complications including their true frequencies. POPULATION AND METHODS: We report a serie of 100 NF1 children who were followed-up during 4 years in a specialized center at the Tours University Hospital. Three hospital check-up at 2-5, 6-7, 14-15 years of age were performed as well as an annual physical examination. RESULTS: In our serie, the mean age was 7.8 years old with a sex ratio of 1. The mean age at diagnosis was 3.8 years old and the main diagnosis criteria were the café-au-lait spots and the family history for 80% of the patients. The optic nerve glioma has a low frequency of 5%. Learning disabilities clearly represent the most frequent complication (46% of the patients). CONCLUSION: An early detection of these difficulties is a priority for the appropriate management of these children.

Adolescent↗

[Spasmodic torticollis caused by metoclopramide: a rare etiology of C1-C2 rotatory pseudoluxation in children].

Torticollis in children must always instigate a search for trauma. Many other etiologies can be found. The authors report a case of postmedicinal atlantoaxial rotatory pseudoluxation (AARP) occurring in a child. This child had fallen down in the morning with head trauma followed by headache. Clinically, a stiff neck with an irreducible right rotation of his neck, and an osteotendinous hyperreflexia were noted. There was a C1-C2 rotatory dislocation with no traumatic lesion on the cervical CT scan. After a few hours, the torticollis spontaneously reduced and then reappeared on the left side. This clinical fluctuation and the absorption of metoclopramide (Primpéran) started in the morning for acute gastroenteritis provided the diagnosis of AARP. This entity was confirmed by the good clinical and radiological follow-up and was caused by the substantial ligament laxity of the craniovertebral junction encountered in children. The analysis of medical imaging and the systematic search for a medicinal cause helped make the right diagnosis.

Cervical Vertebrae↗

Analysis of LRRK2 functional domains in nondominant Parkinson disease.

A comprehensive sequence analysis of 29 exons that code for the functional domains of LRRK2 in 160 nondominant Parkinson disease (PD) patients was performed. Novel variant screening in a further 470 sporadic PD patients and 630 controls revealed two novel variants (R1067Q and IVS33 + 6 T>A), which are likely to be pathogenic in five patients. One patient presented initially with a typical essential tremor phenotype, expanding the phenotypic spectrum of LRRK2 mutations.

Adult↗

[Epidemiological survey of wrist fractures in children].

PURPOSE OF THE STUDY: The incidence of wrist fractures is increasing in children. We undertook an epidemiological survey in western France to determine characteristic features. MATERIAL AND METHODS: A prospective multicentric study was conducted over one year in five university hospital centers in western France. The survey included 839 wrist fractures in children aged 6 to 16 years. The following criteria were recorded: age and gender, date and energy of the trauma, side and description of the fracture. Displacement was measured on the AP and lateral radiographs. RESULTS: The boys were older than the girls at the time of the wrist fractures, generally during the summer season (May to October). The left wrist was involved in 55% of the fractures; 83% were metaphyseal fractures. Fractures with epiphyseal detachment were more frequent in adolescents and occurred after high-energy trauma. Metaphyseal fractures were more common in girls than in boys. Displacement was greater in older children, particularly in case of epiphyseal detachment. DISCUSSION: We did not observe the male predominance often reported in our country. The girls probably practice sports as much as boys.

Adolescent↗

[Femoral implants of coral and ceramics: histological results after 120 days].

The authors have made an histological study of the evolution, after 120 days, of coral implant and tricalcic phosphate ceramic implant in each femur of 12 rabbits. The results have shown on the one hand that ceramic is resorbed faster than coral, on the other hand that for both types of biomaterials the resorption was much faster for the implants in contact with the bone-marrow than for those which were not.

Animals↗

A cytosolic NAD-dependent deacetylase, Hst2p, can modulate nucleolar and telomeric silencing in yeast.

In budding yeast, the silent information regulator Sir2p is a nuclear NAD-dependent deacetylase that is essential for both telomeric and rDNA silencing. All eukaryotic species examined to date have multiple homologues of Sir two (HSTs), which share a highly conserved globular core domain. Here we report that yeast Hst2p and a mammalian Hst2p homologue, hSirT2p, are cytoplasmic in yeast and human cells, in contrast to yHst1p and ySir2p which are exclusively nuclear. Although yHst2p cannot restore silencing in a sir2 deletion, overexpression of yHst2p influences nuclear silencing events in a SIR2 strain, derepressing subtelomeric silencing while increasing repression in the rDNA. In contrast, a form of ySir2p carrying a point mutation in the conserved core domain disrupts both telomeric position effect (TPE) and rDNA repression at low expression levels. This argues that non-nuclear yHst2p can compete for a substrate or ligand specifically required for telomeric, and not rDNA repression.

Amidohydrolases↗

Myc induces the nucleolin and BN51 genes: possible implications in ribosome biogenesis.

The c-Myc oncoprotein and its dimerization partner Max bind the DNA core consensus sequence CACGTG (E-box) and activate gene transcription. However, the low levels of induction have hindered the identification of novel Myc target genes by differential screening techniques. Here, we describe a computer-based pre-selection of candidate Myc/Max target genes, based on two restrictive criteria: an extended E-box consensus sequence for Myc/Max binding and the occurrence of this sequence within a potential genomic CpG island. Candidate genes selected by these criteria were evaluated experimentally for their response to Myc. Two Myc target genes are characterized here in detail. These encode nucleolin, an abundant nucleolar protein, and BN51, a co-factor of RNA polymerase III. Myc activates transcription of both genes via E-boxes located in their first introns, as seen for several well-characterized Myc targets. For both genes, mutation of the E-boxes abolishes transcriptional activation by Myc as well as repression by Mad1. In addition, the BN51 promoter is selectively activated by Myc and not by USF, another E-box-binding factor. Both nucleolin and BN51 are implicated in the maturation of ribosomal RNAs, albeit in different ways. We propose that Myc, via regulation of these and probably many other transcriptional targets, may be an important regulator of ribosome biogenesis.

Cell Cycle Proteins↗

The eukaryotic promoter database (EPD).

The Eukaryotic Promoter Database (EPD) is an annotated non-redundant collection of eukaryotic POL II promoters for which the transcription start site has been determined experimentally. Access to promoter sequences is provided by pointers to positions in nucleotide sequence entries. The annotation part of an entry includes a description of the initiation site mapping data, exhaustive cross-references to the EMBL nucleotide sequence database, SWISS-PROT, TRANSFAC and other databases, as well as bibliographic references. EPD is structured in a way that facilitates dynamic extraction of biologically meaningful promoter subsets for comparative sequence analysis. WWW-based interfaces have been developed that enable the user to view EPD entries in different formats, to select and extract promoter sequences according to a variety of criteria, and to navigate to related databases exploiting different cross-references. The EPD web site also features yearly updated base frequency matrices for major eukaryotic promoter elements. EPD can be accessed at http://www.epd.isb-sib.ch

Database Management Systems↗

[Scapular pain and supra-scapular neuropathy in sports medicine].

Eight patients with shoulder pain are reported with a history of athletic activities. On examination, performed with a delay of several months, all patients had painful paresis and atrophy of spinati fossa. Electroneuromyography was carried out in all cases and showed a suprascapular nerve axonal loss from the spinati muscles or infraspinatus muscle, signs of denervation-reinnervation in spinati or infraspinatus muscles, normal examination of other scapular girdle muscles, and a coordinate spinati contraction with shoulder displacement excluding rotator cuff tears. All patients had conservative treatment and only two improved. Six patients underwent surgical decompression of the suprascapular nerve; in three, motor function clearly improved, and in three others pain improved. The factors leading to entrapment include stretch mechanisms associated with shoulder movements, leading to suprascapular nerve liability to mechanical lesions. In patients with shoulder pain, the authors recommend an early electrophysiological work-up to recognize an isolated suprascapular neuropathy. The surgical decompression of the nerve should be based on persistent shoulder pain after conservative treatment.

Adolescent↗

The Eukaryotic Promoter Database (EPD): recent developments.

The Eukaryotic Promoter Database (EPD) is an annotated non-redundant collection of eukaryotic POL II promoters, for which the transcription start site has been determined experimentally. Access to promoter sequences is provided by pointers to positions in nucleotide sequence entries. The annotation part of an entry includes description of the initiation site mapping data, cross-references to other databases, and bibliographic references. EPD is structured in a way that facilitates dynamic extraction of biologically meaningful promoter subsets for comparative sequence analysis. Recent efforts have focused on exhaustive cross-referencing to the EMBL nucleotide sequence database, and on the improvement of the WWW-based user interfaces and data retrieval mechanisms. EPD can be accessed at http://www.epd.isb-sib.ch

Algorithms↗

Isolated and combined lesions of the axillary nerve. A review of 146 cases.

We have assessed the final strength of the deltoid in 121 patients who had repair of isolated or combined lesions of the axillary (circumflex) nerve and were available for statistical analysis. Successful or useful results were achieved in 85% after grafting of isolated lesions. The strength was statistically better when patients had grafting of the axillary nerve within 5.3 months from the time of injury. The dramatic decrease in the rate of success seen with longer delays suggests that surgery should be undertaken within three months of injury. A statistically significant downward trend of the rate of success was noted with increasing age. The force and level of injury to the shoulder play an important role in the type, combination and level of nerve damage and the incidence of associated rotator-cuff, vascular and other injuries to the upper limb. Management of isolated and combined lesions of the axillary nerve after injury to the shoulder needs to be thorough and systematic.

Adolescent↗