Bradykinin and phorbol ester but not 5-HT2B receptor activation stimulate phospholipase D activity in the rat stomach fundus.

1. Serotonin has been implicated as a mediator involved in migraine headache, an effect that may involve central 5-HT2B receptor activation. 5-HT2B receptor signal transduction in controversial. 2. Rat stomach fundus contraction to serotonin has been used as a model for 5-HT2B receptor activation. Serotonin-induced contractility involves intracellular calcium release and activation of protein kinase C without stimulation of phosphoinositide (PI) hydrolysis. 3. Since phospholipase D (PLD) activation results in phosphatidic acid production, which can release intracellular calcium and provide diacylglycerol for PKC activation, the purpose of this study was to determine whether the 5-HT2B receptor coupled to PLD activation using the rat stomach fundus as a model system. 4. Using phosphatidylethanol production to measure PLD activity, both bradykinin (0.01-1 microM) and phorbol dibutyrate (PDBu, 1 microM) stimulated PLD activity in rat stomach fundal strips, indicating that this tissue possesses an active PLD system. 5. Under identical conditions, 5-hydroxytryptamine (5-HT) failed to stimulate PLD activity over a concentration range (1 nM-1 microM) documented to induce 5-HT2B receptor-mediated contraction in rat stomach fundus. Thus, the 5-HT2B contractile receptor in rat stomach fundus is not coupled to PLD activation, whereas both bradykinin and phorbol ester do couple to PLD.

[Is periodontal guided tissue regeneration a reproducible technic? A review of the literature]. / La régéneration tissulaire guidée parodontale est-elle une technique reproductible? Une revue de la littérature.

Guided tissue regeneration (GTR) has been developed as a surgical technique enabling the complete regeneration of the periodontal attachment apparatus. Among various periodontal tissues, the root, cementum and the alveolar bone, as well the Sharpey collagenic fibers linking the cementum to the bone, are of particular interest. As demonstrated in this literature review, we could globally conclude to date, that most of the publications confirm the biological and clinical potential of GTR, although in some publications, this opinion is not being shared. A number of factors influence the outcome of the regenerative therapy, some relating to the patient such as the smoking habits and the level of oral hygiene, others relating to the type of implanted biomaterial or the surgical technique. A better understanding of the periodontal healing mechanisms as well as the continuous research and progress in the field of biomaterials, chemical mediators and growth factors, are likely to further increase the predictibility of the periodontal regenerative treatments.

[Decision to extract for periodontal reasons]. / Décisions d'extraction pour raisons parodontales.

The decisions to extract that are discussed here mainly relate to severe periodontal bone losses and plain interradicular attacks. Extractions for periodontal reasons appear at several treatment stages: immediate extraction in terminal stages, e.g. for teeth without any strategic importance, or deferred extraction if one chooses to wait for treatment response. The elements of the decision are various: function and strategic importance of the tooth, extension of the lesion, level of the interradicular attack, any endoperiodontal lesions, fractures and luxations, radicular proximity, implication of wisdom teeth, evolution after treatment. All these factors are discussed.

[An esthetic crown lengthening technic of the clinical crown. Rapid orthodontic extrusion]. / Une technique esthétique d'allongement de la couronne clinique. L'egression orthodontique rapide.

Rapid orthodontic root extrusion is an esthetic technique for clinical crown lengthening. Associated with periodontal surgery, it exposes subgingival lesions and preserves an harmonious gingivo-osseous morphology. This conservative technique is easy to apply by the general dentist as it requires non specialised material.

HLA: a review of actual knowledge and perspectives in periodontology.

The Major Histocompatibility Complex is a relatively poorly explored research area among the various immunological aspects of periodontal diseases. After a recall of general concepts, the authors first describe the general HLA-pathology association and then, the reported HLA-periodontal disease associations. HLA theoretical potential interests are multiple. Typing results show, on one hand, no clear correlation with juvenile periodontitis (diminution of A 2, augmentation of A 9, A 28, Bw 15 and Bw 35) but on the other hand, a more constant correlation between HLA A 9 and rapidly progressive periodontitis. Besides, three resistance factors have been reported: A 10, B 5 and A 28.

Ceftazidime nephrotoxicity in rats.

The nephrotoxicity of ceftazidime compared with that of cefazolin or cephaloridine and the capacity of ceftazidime to enhance the nephrotoxicity of tobramycin were evaluated in rats. Only cephaloridine and tobramycin given alone altered creatinine clearance or caused significant histological injury. Our data suggest that ceftazidime is no more nephrotoxic than cefazolin and does not enhance the nephrotoxicity of tobramycin.

Effects of moxalactam and cefotaxime on rabbit renal tissue.

To determine and compare the effects of moxalactam and cefotaxime on kidneys, we gave these drugs in doses of 750 and 1,500 mg/kg to rabbits for 7 days. Cephaloridine was included as a positive control. Neither moxalactam nor cefotaxime at either dose caused lysosomal enzymuria, changes visible by light microscopy or increased plasma creatine. Both drugs caused minor alterations in glomerular ultrastructure at the higher dose. Cephaloridine, on the other hand, caused widespread renal functional and morphological damage. We conclude that in rabbits, both moxalactam and cefotaxime are remarkably nonnephrotoxic.

Effect of (-)-hydroxycitrate on development of obesity in the Zucker obese rat.

Young Zucker lean (Fa/-) and obese (fa/fa) female rats were fed the fatty acid synthesis inhibitor (-)-hydroxy-citrate as a dietary admixture for 39 days. In the lean rats, (-)-hydroxycitrate treatment decreased body weight, food intake, percent of body fat, and fat cell size. In the obese rat, food intake and body weight were reduced but the percent of body fat remained unchanged. Throughout the treatment period, obese rats maintained a fat cell size equivalent to their obese controls. Although a reduction in fat cell number in the obese rats occurred during the treatment period, marked hyperplasia was observed during the posttreatment period. The results of this study indicate that the obese rat, despite a substantial reduction in body weight produced by (-)-hydroxycitrate, still defends its obese body composition.