Impact of Treatment with Unilateral Implant- Supported Fixed Partial Prosthesis on the Frequency of Masticatory Side Switches in Patients with Unilateral Posterior Missing Teeth.

This study aimed to determine the impact of treatment with an implant-supported fixed partial prosthesis (ISFPP) on the frequency of masticatory side switches in patients with unilateral posterior missing teeth. This was a prospective study of 30 patients with unilateral posterior missing teeth treated with one-, two-, or three-unit ISFPPs. Comparison was with 10 healthy individuals with complete natural dentitions. Each participant performed masticatory assays, which involved chewing pieces of silicon inside a latex bag, at baseline and at 3-months' follow-up. The frequency of masticatory side switches was reported as the masticatory side-switch index: the number of side switches divided by the maximum number of possible switches. Data were analyzed by Kruskal-Wallis, Mann-Whitney U test, or Wilcoxon test, as appropriate. At baseline, the masticatory side-switch index was lower only in patients with three missing teeth than in controls. At 3 months after treatment, a significant increase in the masticatory side-switch index was only observed in patients treated with three restorative units. Treatment with ISFPPs does not change the masticatory side-switch frequency in patients with unilateral posterior missing teeth, though it could increase it in patients with three missing teeth.

Peripheral, functional and postural asymmetries related to the preferred chewing side in adults with natural dentition.

The aim of this cross-sectional study was to determine the preferred chewing side and whether chewing side preference is related to peripheral, functional or postural lateral preferences. One hundred and forty-six adults with natural dentition performed three masticatory assays, each consisting of five trials of chewing three pieces of silicon placed into a latex bag for 20 cycles, either freestyle or unilaterally on the right- or left-hand side. Occlusal contact area in the intercuspal position, maximum bite force, masticatory performance and cycle duration were measured and the lateral asymmetry of these variables was calculated. Laterality tests were performed to determine handedness, footedness, earedness and eyedness as functional preferences, and hand-clasping, arm-folding and leg-crossing as postural lateral preferences. The preferred chewing side was determined using three different methods: assessment of the first chewing cycle for each trial, calculation of the asymmetry index from all cycles and application of a visual analogue scale. Bivariate relationship and multiple linear regression analyses were performed. Among unilateral chewers, 77% of them preferred the right side for chewing. The factors most closely related to the preferred chewing side were asymmetry of bite force, asymmetry of masticatory performance and earedness, which explained up to 16% of the variance. Although several functional or postural lateral preferences seem to be related to the preferred chewing side, peripheral factors such as asymmetry of bite force and of masticatory performance are the most closely related to the preferred chewing side in adults with natural dentition.

Oncogene expression in rat hepatomas and during hepatocarcinogenesis.

In this study we examined oncogene expression in several Morris hepatomas. We found elevated transcripts for Ha-ras, Ki-ras, and the myc oncogenes, while the src oncogene was not increased. Northern analysis revealed transcript sizes of 1.4 kb for Ha-ras and 2.5 kb for myc. Analysis of primary tumors induced by the carcinogen 3'-methyl-4-dimethylaminoazobenzene (3'-MDAB) showed increasing oncogene transcript production with increasing length of diet. The results show enhanced ras and myc expression in rat hepatocellular carcinomas and during hepatocarcinogenesis.

Systemic movement of Agrobacterium tumefaciens in several plant species.

AIMS: The systemic movement of Agrobacterium spp. inside plants of different species was studied to determine the most valuable diagnostic methodology for their detection. METHODS AND RESULTS: Pathogenic agrobacteria were detected by isolation and PCR in tissue away from primary tumours in tomato plants grown in the presence of Agrobacterium spp. Moreover, this bacterium was also able to induce secondary tumours beyond the inoculation site. In addition, the capacity of agrobacteria to translocate and induce secondary tumours was analysed in rose, grapevine, chrysanthemum, cherry and peach x almond hybrid GF677. No differences among strains of Agrobacterium spp. were detected in secondary tumour development, although some of them induced a significantly higher number of primary tumours in some species. Movement of inoculated pathogenic cells of four strains was also demonstrated in symptomless portions of the plant stems by isolation and PCR. Finally, pathogenic agrobacteria were detected in root, crown and stem portions of naturally infected walnuts. In all assays, PCR was the most efficient technique for detecting the movement of Agrobacterium spp. within the plants. CONCLUSIONS: Migration of agrobacteria inside plants is a complex phenomenon and more extensive than previously reported. Therefore, efficient and sensitive detection methods such as PCR must be used to select clean plants to avoid latent infections of Agrobacterium spp. SIGNIFICANCE AND IMPACT OF THE STUDY: The results show that migration of Agrobacterium spp. could be relatively frequent in several cultivated fruit trees, and systemic infections should be taken into account when designing strategies for controlling crown gall disease.