Changes in the distributions of fluorine-18-labelled fluoro-2-deoxy-d-glucose accumulation into tongue-related muscles after dissection in patients with tongue cancer

OBJECTIVES

To elucidate the changes in the distributions of fluorine-18-labelled fluoro-2-deoxy-d-glucose (¹⁸F-FDG) accumulation in the tongue muscles of patients following four kinds of surgical operations for tongue cancers.

METHODS

The changes in the distributions of ¹⁸F-FDG accumulations in the tongue muscles on positron emission tomography (PET)-CT, in association with imaging findings on CT and MRI, were retrospectively analyzed before and after four kinds of surgical operations for 50 patients with tongue cancers.

RESULTS

¹⁸F-FDG-PET-positive areas appeared at the back of the intrinsic muscles of the tongue after invasive surgery for tongue cancers despite the absence of abnormal findings on CT and MRI. A correlation between the standardized uptake value maximum of ¹⁸F-FDG in the intrinsic muscles and the degree of invasiveness of the surgical procedures for tongue cancers (r = 0.539, p < 0.01) was found.

CONCLUSIONS

It is important to pay attention to the changes in ¹⁸F-FDG distributions in the intrinsic muscles of the tongue before and after invasive surgery despite the absence of abnormal findings on CT and MRI when evaluating the tongue on ¹⁸F-FDG-PET.

Expression of GAD67 and Dlx5 in the taste buds of mice genetically lacking Mash1

It has been reported that a subset of type III taste cells express glutamate decarboxylase (GAD)67, which is a molecule that synthesizes gamma-aminobutyric acid (GABA), and that Mash1 could be a potential regulator of the development of GABAnergic neurons via Dlx transcription factors in the central nervous system. In this study, we investigated the expression of GAD67 and Dlx in the embryonic taste buds of the soft palate and circumvallate papilla using Mash1 knockout (KO)/GAD67-GFP knock-in mice. In the wild-type animal, a subset of type III taste cells contained GAD67 in the taste buds of the soft palate and the developing circumvallate papilla, whereas GAD67-expressing taste bud cells were missing from Mash1 KO mice. A subset of type III cells expressed mRNA for Dlx5 in the wild-type animals, whereas Dlx5-expressing cells were not evident in the apical part of the circumvallate papilla and taste buds in the soft palate of Mash1 KO mice. Our results suggest that Mash1 is required for the expression of GAD67 and Dlx5 in taste bud cells.