[Cervicofacial ulcerations caused by dental infection in children]. / Ulcérations cervicofaciales liées à un foyer infectieux dentaire chez l'enfant.

UNLABELLED: In children, chronic cervicofacial ulceration related to dental infection is rare. Thus the diagnosis is often late and the treatment is consequently delayed. We report 2 new cases. CASES REPORT: A 13-year-old boy presented with a 1-year history of chronic and suppurative ulceration on the right cheek. Culture was positive for actinomycetes. In spite of a prolonged and miscellaneous antibiotherapy, the lesion recured. The ulceration healed after the eradication of infection on a right superior molar. A 12-year-old girl presented with a right sub-mandibular ulceration, which appeared 3 months before. This lesion did not respond to penicillinotherapy given during 3 months. An infection on a right inferior molar was diagnosed on a tomodensitometry. 3 months after the tooth extraction, the ulceration healed without recurrence. CONCLUSION: These cases emphasize the interest to look for a dental infection at the origin of chronic cervicofacial lesion.

[Localized loss of facial tissue. Criteria of use of extra-oral implants and clinical cases]. / Pertes de substance faciale localisées. Critères de recours aux implants extra-oraux et cas cliniques.

Osseointegrated maxillofacial epitheses are an interesting therapeutic response for rehabilitation after loss of facial tissue when reconstructive plastic surgery cannot be proposed. We analyzed the criteria used for deciding on this type of treatment for the loss of local areas of auricular tissue, the nasal pyramid and the orbitopalpebral region, presenting individual clinical examples.

Contractile activity modulates atrial natriuretic factor gene expression in neonatal rat ventricular myocytes.

[Ca2+]i transients, and the activation of Ca(2+)-sensitive kinases have been considered potential signaling mechanisms regulating ANF gene expression in cultured neonatal rat ventricular myocytes (NRVM). However, it is unclear whether [Ca2+]i is directly involved, or is indirectly involved by generating additional mechanical signals via contractile activity. Primary cultures of spontaneously contracting NRVM (CON), and NRVM treated for 48 h with verapamil (V, 10 microM), KCl (50 mM), or 2,3-butanedione monoxime (BDM, 7.5 mM) were used to delineate the affects of contractile activity v [Ca2+]i. Verapamil, a calcium, channel blocker, inhibits contraction and decreases [Ca2+]i. High [K+]o causes membrane depolarization, loss of contraction, and elevates [Ca2+]i; whereas BDM strongly inhibits contractile activity but only modestly reduces [Ca2+]i transients. ANF production, as assessed by radioimmunoassay, was significantly reduced upon contractile arrest independently of [Ca2+]i levels. Northern blotting analysis demonstrated that contractile arrest also reduced ANF mRNA levels. Transient transfection of a 3003 bp ANF promoter-luciferase expression plasmid in CON, V, KCl, and BDM-treated NRVM demonstrated marked down-regulation of ANF promoter activity in all of the contractile arrested myocytes. These results indicate that the activation of Ca(2+)-sensitive processes alone are insufficient to maintain high levels of ANF gene expression and peptide production in NRVM.

Cyclic stretch down-regulates calcium transporter gene expression in neonatal rat ventricular myocytes.

Abnormal intracellular Ca2+ handling in hypertrophied and failing hearts is partly due to changes in Ca2+ transporter gene expression, but the mechanisms responsible for these alterations remain largely unknown. We previously showed that intrinsic mechanical load (i.e. spontaneous contractile activity) induced myocyte hypertrophy, and down-regulated SR Ca2+ ATPase (SERCA2) gene expression in cultured neonatal rat ventricular myocytes (NRVM). In the present study, we examined whether extrinsic mechanical load (i.e. cyclic stretch) also induced NRVM hypertrophy, and led to down-regulation of SERCA2 and other Ca2+ transporter genes which have been associated with cardiac hypertrophy and failure in vivo. NRVM were maintained in serum-free culture medium under control conditions, or subjected to cyclic mechanical deformation (1.0 Hz, 20% maximal strain, 48 h). Under these conditions, cyclic stretch induced NRVM hypertrophy, as evidenced by significant increases in total protein/DNA ratio, myosin heavy chain (MHC) content, and atrial natriuretic factor (ANF) secretion. Cyclic stretch also induced the MHC isoenzyme "switch" which is characteristic of hemodynamic overload of the rat heart in vivo. Cyclic stretch significantly down-regulated SERCA2 and ryanodine receptor (RyR) mRNA and protein levels, while simultaneously increasing ANF mRNA. In contrast, Na+-Ca2+ exchanger and phospholamban mRNA levels were unaffected. Load-dependent SERCA2 and RyR down-regulation was independent of Ca2+ influx via voltage-gated, L-type Ca2+ channels, as cyclic stretch down-regulated SERCA2 and RyR mRNA levels in both control and verapamil-treated NRVM. These results indicate that extrinsic mechanical load (in the absence of other exogenous stimuli) induces NRVM hypertrophy and causes down-regulation of Ca2+ transporter gene expression. This in vitro model system should prove useful to dissect the intracellular signaling pathways responsible for transducing this phenotype during cardiac hypertrophy and heart failure in vivo.

[Bone-anchored implants: comparison of the techniques and values of endo- and juxta-bone implants]. / Les épithèses implanto-portées: technique et intérêt comparés des implants endo et juxta-osseux.

Extra-oral implants have been used for well-defined application for nearly 20 years; for tupoorting maxillo-facial prostheses and for bone anchored hearing aids (BAHA). In both of these applications, the bone-anchored prostheses support transcutaneous abutments. It is the junction between the implant and the abutment which ensures, given certain preconditions, the permanent percutaneous connection (PPC). The authors describe the two types of implants currently in use-intra- and juxta-osseous implants. They then give a brief description of the two techniques. The advantages and disadvantages of each system are summarised, as well as the conditions required for permanent survival of a PPC.