Mechanism of Catechol-O-methyltransferase Regulating Orofacial Pain Induced by Tooth Movement.

OBJECTIVE: To explore the mechanism of catechol-O-methyltransferase (COMT) in tooth movement pain. METHODS: The experimental groups were randomly allocated into the healthy control, sham operation, model, model+shCOMT experimental, model+shCOMT control, and model+COMT antagonist groups. A tooth movement pain model was established. The pain stimulation and behavior test were performed. The duration of grooming behavior was determined. The appropriate experimental force and duration for application were selected. COMT shRNA vector was constructed and packaged as adenovirus. The shCOMT adenovirus was injected into the left infraorbital foramen. Seven days later, the trigeminal ganglia of all treatment groups were obtained. The COMT and IL-17 expressions were detected by western blot. The appropriate COMT antagonist concentration was selected. The pathological results of each group were detected by HE staining. The tooth movement distance was determined. The COMT gene expression was detected by FISH. The COMT and IL-17 expressions in the right trigeminal ganglion tissue of each group were detected by western blot. RESULTS: The 60 g force and 14-day duration required the lowest stimulus intensity, the duration of grooming behavior was the longest, and the effect on COMT and IL-17 was the most significant. In the model group, formation of digestive cavity was seen in the trigeminal ganglion tissue, with infiltration of inflammatory cells, upregulation of the COMT and IL-17 expressions, and significant increase in the tooth movement distance. Compared with the model group, the shCOMT experimental group and the COMT antagonist group significantly improved the trigeminal ganglion tissue injury, significantly decreased the tooth movement distance, and significantly inhibited the COMT and IL-17 expressions. CONCLUSION: The efficiency of tooth movement can be influenced by interfering the COMT-related gene expression. This proves that the COMT system can regulate the orthodontic tooth movement pain.

Clinical implications of chemotherapy-induced diarrhea in patients with cancer.

Diarrhea is a common, often dose-limiting toxicity associated with cancer chemotherapy treatment. However, the problem is not well recognized and frequently is not managed appropriately. The primary objectives of the current study were to describe the sociodemographic and clinical characteristics of cancer patients with chemotherapy-induced diarrhea (CID) and describe the clinical consequences of CID on treatment changes. This was a retrospective review of medical records from 378 cancer patients who experienced diarrhea while receiving chemotherapy at 25 geographically dispersed US cancer clinics. Severe diarrhea (National Cancer Institute-Common Toxicity Criteria grades 3 or 4) was experienced by about one third of patients during their chemotherapy. Patients who experienced CID underwent changes in their chemotherapy treatment, including dose reductions (45%), delays in therapy (71%), reduction in dose intensity (64%), and discontinuation of therapy (3%). Dose reductions were statistically significant. Although the majority of diarrhea was grade 1, almost one half of all patients required dosing reductions, and more than one half of these patients experienced dosing delays. Changes to chemotherapy treatment resulting from CID may ultimately impact patient clinical outcomes.