A novel insight into the anticancer mechanism of metformin in pancreatic neuroendocrine tumor cells.

The antidiabetic drug metformin displays anticancer properties in several neoplasms. In pituitary NETs, aryl hydrocarbon receptor-interacting protein (AIP) is up-regulated by the somatostatin analog octreotide. Metformin inhibited QGP-1 cell proliferation in a dose- and time-dependent manner, at concentrations similar to those achievable in treated patients (-31 ± 12%, p < 0.05 vs basal at 100 µM). Moreover, metformin decreased pancreatic neuroendocrine tumors (PAN-NETs) cell proliferation (-62 ± 15%, p < 0.0001 vs basal at 10 mM), without any additive effect when combined with octreotide. Both octreotide and metformin induced AIP up-regulation. AIP silencing abolished the reduction of mTOR phosphorylation induced by metformin and octreotide. Moreover, metformin decreased HSP70, increased Zac1 and AhR expression; these effects were abolished in AIP silenced QGP-1 cells. In conclusion, metformin acts as an anticancer agent in PAN-NET cells, its activity is mediated by AIP and its interacting proteins. These findings provide a novel insight into the antitumorigenic mechanism of metformin.

Effect of a prefabricated anterior bite stop on electromyographic activity of masticatory muscles.

STATEMENT OF PROBLEM: Patients are often treated for signs and symptoms in the masticatory musculature, which may be manifested as pain and/or conditions that cause difficulty in recording jaw relation records. A quick, easy method to alleviate these signs and symptoms would be helpful. PURPOSE: This study measured the effect of a prefabricated anterior bite stop on the electromyographic activity of the anterior temporalis, posterior temporalis, masseter and anterior digastric during clenching, and grinding tasks. MATERIAL AND METHODS: A prefabricated anterior bite stop was fabricated for 30 randomly selected subjects. Electromyographic surface electrodes were placed on the right and left sides of these muscles. Electromyographic activity was measured during clenching and grinding both with and without the anterior bite stop. RESULTS: The anterior bite stop had a significant effect in decreasing electromyographic activity for both clenching and grinding for all the tested muscles, except the anterior digastric. CONCLUSIONS: For this patient population, the ready-made anterior bite stop reduced electromyographic muscle activity for the anterior and posterior temporalis and the masseter muscles during both clenching and grinding.

A computerized model for teaching various methods of positioning the condyles to centric relation.

The entire masticatory system is within the realm of the dentist's responsibility, and therefore requires the dentist to have a working knowledge and understanding of the TMJs, neuromuscular system, and occlusion as well as the teeth and periodontal structures. This article presents how a computerized model can help dentists help their patients with TMJ disorders.

The effectiveness of equilibration in the improvement of signs and symptoms in the stomatognathic system.

Signs and symptoms of the breakdown of the various components of the stomatognathic system, in particular the TMJ structures, masticatory muscles, dental structures, and periodontium, can have a variety of causes. Occlusal interferences have been implicated as one contributing factor in these areas of breakdown. If this is indeed the case, then elimination of these interferences should improve these signs and symptoms. A retrospective study involving 30 practicing dentists who make up part of the visiting faculty of the Pankey Institute analyzed a variety of signs and symptoms both prior to equilibration and after equilibration to elucidate signs and symptom dynamics following treatment.

The reproducibility of centric relation: a clinical approach.

This study addresses the reproducibility of the centric relation, or CR, position. Using bimanual manipulation, several dentists were randomly assigned to one of five patients to clinically determine CR and record this position by using the same wax recording technique. These bite records, which were then analyzed by using the Denar Centri-Check marking system (Teledyne Water-Pik), were found to capture condylar positions with a maximum variation of 0.1 millimeter, as measured within the tolerances of the Denar Centri-Check.

Definitive diagnostic waxing with light-cured composite resin.

The benefits of perceptive treatment planning for prosthodontics are discussed, and a method of developing diagnostic waxing with light-cured composite resin is described. The advantages of this programmed approach are illustrated with clinical examples.