[Synthetic calcium phosphate ceramics in secondary alveoloplasty]. / Les céramiques phosphocalciques synthétiques dans l'alvéoloplastie secondaire.

INTRODUCTION: Bone substitutes are rarely used in the reconstruction of cleft lip and palate. The graft material of choice is cancellous bone, harvested in the hip or tibia. Tibial harvesting may lead to postoperative morbidity, or even complications. This has lead surgeons to develop alternative solution. We present a secondary alveolar bone grafting technique using synthetic calcium phosphate ceramics. OBSERVATION: A patient presenting with a complete unilateral cleft lip and palate was treated by alveolar bone grafting at the age of nine years, using a mixture of autologous bone, harvested on the operative field, and particles of biphasic calcium phosphate (BCP); the graft was included in a platelet rich plasma (PRP) gel. The patient was followed up for eight years after the procedure. No sign of early or late infection was observed. At the end of facial growth, the cuspid had erupted correctly in a safe periodontal environment. Sequential X-rays showed complete filling of the initial bone defect, progressive resorption of ceramics, and spontaneous eruption of the cuspid. DISCUSSION: In this long-term follow-up report, the use of BCP mixed with autologous bone did not interfere with dental eruption or maxilla growth. A second bone-harvesting site was thus avoided. BCP could be a suitable alternative to autologous bone graft for secondary alveoloplasty.

[Lesions of the lingual nerve during extraction of the mandibular wisdom teeth. Consequences--etiopathogenesis--prevention--prognosis--legal medical aspects]. / Lésions du nerf lingual au cours de l'extraction de la dent de sagesse mandibulaire. Conséquences-etiopathogénie-prévention-evolution-aspects médicaux légaux.

A brief review of the lingual nerve anatomy is followed by an examination of the consequences of injury to the lingual nerve during mandibular wisdom tooth extraction on sensibility and sensorial activities. The circumstances of such injury are described as a function of the position of the tooth together with means of prevention. The clinical course of injury to the lingual nerve is unpredictable and varies over time and in quality of recovery. No prognosis can be made before a reasonable delay of 18 months to 2 years. Prevention remains the best treatment and consists of using a flexible bar to protect the nerve during the operation. Rate of legal disability compensation is estimated at 2 to 5%.

[Synthesis, biological activity and encapsulation of new adrenergic beta-amino alcohols in phospholipid liposomes]. / Synthèse, activité biologique et encapsulation de nouveaux beta-amino-alcools adrénergiques dans des liposomes phospholipidiques.

New beta-amino-alcohols were synthesized and showed beta-blocking biological activity. These potential drugs, as well as natrium salicylate, have been entrapped in phospholipid liposomes. Drug-containing liposomes were prepared from egg lecithin and DPPC (Dipalmitoylphosphatidylcholine) by the injection method. Turbidity measurements and dynamic light scattering were used to characterise the liposome and to study their stability during storage. The entrapment efficiency of the drugs in liposomes was correlated to the partition coefficient of the drugs.

Effect of the lipid phase transition on the kinetics of H+/OH- diffusion across phosphatidic acid bilayers.

The kinetics of H+/OH- diffusion across dimyristoyl phosphatidic acid bilayer membranes was measured by following the absorbance of the pH-sensitive indicator Cresol red (o-cresolsulfonphthalein) entrapped in single lamellar vesicles after rapidly changing the external pH in a stopped-flow apparatus. The H+/OH- permeability coefficient was found to be in the 10(-5) to 10(-3) cm . s-1 range. The lipid phase transition has a strong influence on the permeation kinetics as the permeability coefficients in the liquid-crystalline phase are drastically higher. The permeability shows no maximum at the phase transition temperature as is the case for other ions, but displays a similar temperature dependence as water permeation. This is also reflected in the high activation energy of approx. 20 kcal/mol and supports the hypothesis (Nichols, J.W. and Deamer, D.W. (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 2038-2042) of H+/OH- permeation via hydrogen bonded water molecules. A second slower kinetic phase is also observed, where the permeation is obviously controlled by counterion diffusion. The temperature dependence of this slow process displays the for ion diffusion characteristic maximum in the permeability at the phase-transition temperature.

Incorporation kinetics of lysolecithin into lecithin vesicles. Kinetics of lysolecithin-induced vesicle fusion.

The incorporation kinetics of L-palmitoylphosphatidylcholine (lysolecithin) into dimyristoyl- and dipalmitoylphosphatidylcholine vesicles and the subsequent aggregation and fusion of the vesicles into larger aggregates were studied by using stopped-flow rapid-mixing techniques. The half-times for the lysolecithin incorporation vary between 50 and 500 ms. The incorporation rate has a maximum in the temperature range of the vesicle phase transition. This process is not diffusion controlled. The rate-limiting step is the incorporation of the lysolecithin monomer into the liquid bilayer. After this fast process, a slow reaction in the 10-50-min time range is observed. The large irreversible increase in turbidity indicates aggregation and fusion of the vesicles. The initial step is a second-order reaction with respect to the vesicle concentration, indicating aggregation or fusion of two vesicles. The aggregation rate passes through a maximum at the phase transition temperature.