Anxiolytic activity of melatonin in mice: involvement of benzodiazepine receptors.

The anxiolytic properties of melatonin are revealed by two behavioral studies. In a free exploratory situation, the holeboard test, melatonin decreased head-dip performance. In an unconditioned conflict test, the light/dark box choice situation, melatonin increased the time spent in the lit box as well as the number of transitions between the two compartments. Melatonin was given in a dose range from 0.5 to 5.0 mg/kg body weight i.p. 30 minutes before testing in daytime. Moreover, the anxiolytic activity of diazepam (2.5 mg/kg i.p.) was evaluated and found to be completely inhibited by the specific benzodiazepine antagonist flumazenil (10 mg/kg i.p. 30 minutes before). In the same manner flumazenil counteracted melatonin activity in the two tests. Involvement of the benzodiazepine/GABAergic system in the anxiolytic activity of melatonin is discussed.

[Bone augmentation in implant surgery]. / Apports osseux et chirurgie implantaire.

The authors experience on twelve patients in the field of bone grafting prior to implant surgery is presented. The technique employed depends largely on the anatomical location of bone insufficiency, such as: 1) Where there is not enough bone beneath sinus locations, grafting with cancellous iliac bone blended with coral particles is suggested. 2) Where the jaw is not sufficiently thick, such as in the incisor-cuspid regions, the authors employ cancellous and/or cortical bone grafts. 3) Horizontal osteotomy and interposition of cortical-cancellous bone graft is proposed where there is a lack of bone height in the incisor-cuspid regions. The results of the various techniques are analysed from a clinical, radiographic and histologic perspective. Twelve patients have been treated with 2 years follow-up.

Chronic stress and memory: implication of the central cholinergic system.

Restraint stress for ten days (two times two hours daily) induces a hypersensitivity of the central cholinergic system, reflected by antagonism to amnesia induced by scopolamine at 0.1 mg/kg in a passive avoidance test and by hypersensitivity to the hypothermic effect of oxotremorine at 1 mg/kg. A restraint stress for 30 days, on the other hand, diminishes animal retention in the passive avoidance test and causes a hyposensitivity to oxotremorine-induced hypothermia, reflecting a hypoactivity of the central cholinergic system. An acute 24-hour stress causes no change. The relationship between chronic stress and associated memory deficits is discussed.

[Action of PMA (phorbol myristate acetate), scopolamine, propranolol, and oxotremorine on memorization of an active or passive avoidance test]. / Action du PMA (phorbol-myristate-acétate), de la scopolamine, du propranolol, et de l'oxotrémorine sur la mémorisation d'un test d'évitement passif ou actif.

The role of various second messengers in the learning and retention of a passive or active avoidance has been investigated in mice. Scopolamine at 3 mg/kg i.p. inhibits muscarinic M1 and M2 receptors and thus acetylcholine activation of the phosphoinositide cycle. This results in amnesia of passive avoidance but has no effect on active avoidance learning. Oxotremorine at 0.05 mg/kg i.p., whose preferential M2 muscarinic action limits acetylcholine release and also inhibits adenylate cyclase activity, causes amnesia of the retention of a passive avoidance and antagonizes the learning of an active avoidance. DL-propranolol at 40 mg/kg i.p., which inhibits cAMP formation, does not affect retention of a passive avoidance but antagonizes that of an active avoidance. Similarly, phorbol myristate acetate a 0.1 mg/kg i.p., which activates protein kinase C, has no effect on the retention of a passive avoidance but antagonizes that of an active avoidance. The results tend to show a distinct role for cAMP-dependent protein kinase, which would participate in memorization processes of an active avoidance, and for protein kinase C, which would participate in that of a passive avoidance. The authors discuss the involvement of different neurophysiological mechanisms as a function of the type of behavior, depending on whether or not it is related to the control of environmental situations.

[The value of projection genioplasty using silicone endoprostheses]. / Intérêt des génioplasties de projection par endoprothèses en silicone.

Use of a silicone menton endoprosthesis appears to be a seductive alternative to menton osteotomy for profile reconstructions of a certain type, whether pure or associated with orthognathic treatment. A strict surgical technique is essential, particularly a limited incision and median and low situated positioning. The advantages and inconveniences of this procedure are described and the need for very selective choice of patients emphasized.

[Evaluation of 16 severe pharyngo-esophageal caustic stenoses. Value of the anterior approach in an ileo-colic transplant]. / Bilan de 16 sténoses caustiques graves pharyngo-oesophagiennes. Intérêt de l'abord antérieur cervical dans la transposition iléo-colique.

Results of treatment of 16 cases of severe pharyngo-esophageal stenosis of caustic origin are reviewed. Emergency treatment is described, the place of otorhinolaryngology in investigation of lesions of upper respiratory and digestive tract discussed, and a description given of a technique of esophagopharyngoplasty by right ileocolic transplant with a suprahyoidal or supraglottic anterior cervical approach with epiglottectomy. Strict selection of patients is essential, taking into account their psychiatric profile. The functional result of this operation, with its long and difficult postoperative course, was inconstant (11 of the 16 cases could be fed liquids and solids by mouth exclusively, ensuring maintenance of body weight, although endoscopic dilatation might be necessary in one or two cases), and appears to depend on the outcome of corrosive lesions and psychologic behavior of patients.

[Involvement of the tympanic bone in chronic otitis (44 cases)]. / Les atteintes du tympanal dans le cadre de l'otite chronique (44 observations).

44 cases of tympanic involvement in the context of chronic otitis are described. 34 occurred during active chronic otitis. This is a rare possibility (approximately 4% of our own cases of chronic otitis). The following may be mentioned amongst them: 21 cases of osteitis, for which the following concepts should be borne in mind: the extreme severity of the chronic otitis responsible, in most instances, ears which had undergone multiple surgery (17/21), lesions exclusively of osteitis, but very extensive in 2/3 of cases (14/21). 7 cases of osteolytic disease, occurring severe or atypical cholesteatomatous chronic otitis and quite often involving associated osteolysis affecting the main VII, the promontory, the bulb of the internal jugular vein, or even the carotid canal. 4 cases of diffuse sub-obstructive osteomatous disease of the walls of the E.A.M., "progressive" development of which over several months was noted in 3 cases. Finally, 2 cases of mixed disease: (osteitis--osteomatoma and osteitis--osteolysis). 8 cases occurred following myringoplasty: this is a rare eventuality (approximately 1%), 1 case only of osteolysis due to iatrogenic cholesteatoma, 7 cases of osteitis, either highly localized and not preventing further myringoplasty (4 cases), or very extensive, finally resulting in a vast evacuation cavity. In 2 cases, a malformation is the origin of involvement of the tympanic at the origin of chronic otitis was felt probable, without it being possible to reach any definite conclusion concerning auriculobranchial fistula or Huschke foramen.