Diagnostic performance of MR imaging of three major salivary glands for Sjögren's syndrome.

OBJECTIVE: We analyzed the diagnostic performance of the MR imaging findings of the parotid, submandibular, and sublingual glands to discriminate between patients with and without Sjögren's syndrome. METHODS: We retrospectively analyzed the correlation between the MR imaging and histopathological findings obtained from 69 patients with clinically suspected Sjögren's syndrome. We evaluated the heterogeneous signal intensity distribution on T1- and T2-weighted images, the multiple high-signal-intensity spots on MR sialograms, and the volume of the parotid, submandibular, and sublingual salivary glands. RESULTS: The multiple high-signal-intensity spots in the parotid gland showed the highest sensitivity and diagnostic accuracy (82% and 83%, respectively). In addition, the multiple high-signal-intensity spots and the heterogeneous signal intensity distribution in the submandibular gland showed high specificity (100% and 88%, respectively). The volume of the submandibular gland, but not that of the parotid or sublingual gland, was smaller in patients with Sjögren's syndrome. CONCLUSIONS: The presence of multiple high-signal-intensity spots on an MR sialogram in the parotid gland should be considered the best diagnostic indicator for Sjögren's syndrome. The presence of spots, heterogeneity, and the change to smaller volumes in the submandibular gland were also helpful because of their high specificity, particularly in advanced cases.

Expression of umami-taste-related genes in the tongue: a pilot study for genetic taste diagnosis.

OBJECTIVE: Expression of taste-related genes in the tongue was analysed to develop a technique for genetic diagnosis of umami taste disorders. MATERIALS AND METHODS: Tissue samples were collected from healthy volunteers by scraping the foliate papillae of the tongue. Immunocytochemistry staining of gustducin, a taste-cell-specific G protein, and gene expression analysis by real-time polymerase chain reaction of ß-actin, gustducin (GNAT3) and umami receptors (T1R1, T1R3 and mGluR1) were performed. Changes in umami receptor expression following application of umami substances onto the tongue were analysed. RESULTS: Gustducin-positive cells were observed in the samples, indicating the presence of taste cells. Gene expression of ß-actin, GNAT3, T1R1 and T1R3 was detected in all seven samples tested, while that of mGluR1 was detected in four samples. Sequence analysis by NCBI Blast showed that each polymerase chain reaction product had a 99% rate of identification of its target sequence. Stimulation of the tongue with monosodium glutamate significantly upregulated the gene expression levels of T1R1 and T1R3, indicating that this method can detect alterations in umami-related gene expression. CONCLUSION: Evaluation of the expression of the umami receptor genes, T1R1 and T1R3, in the tongue may be clinically useful for objective genetic diagnosis of umami taste disorders.

A simple, yet accurate method for detecting and quantifying secretions from human minor salivary glands using the iodine-starch reaction.

The lack of published information about the minor salivary glands is due in part to the difficulties experienced in collecting and quantifying their secretions. In fact, no method exists for measuring their secretions that is both simple and accurate. This investigation examined the accuracy of our newly developed method (which simply employs the iodine-starch reaction) in 10 healthy non-medicated adults. A strip painted with a solution of iodine in absolute alcohol then with a fine starch powder mixed with castor oil was placed at a designated location on the lower-lip mucosa for 2 min to collect saliva. Black-stained spots of various sizes corresponding to the individual glands could be accurately visualized. After removal of the strip, the total stained area (mm2) was calculated by digitizing the spot areas using a computer system. The correlation coefficient (r) between known volumes of saliva and stain size was 0.995, indicating a close correlation. The correlation coefficient (r) between area values obtained in the first trial in each subject (Y) and the second (X; 10 min later) was 0.963, and the simple regression equation was close to Y=X, indicating good reproducibility. The mean flow rate microl/cm2 per min) obtained by converting mean total area to volume and thence to flow rate was 0.49+/-0.26, in good agreement with published values obtained by others. These results suggest that our newly developed method allows both the distribution and secretion rate of the minor salivary glands to be observed, and that it should be of practical value due to its simplicity, accuracy, and reproducibility.

Centrally mediated reflex vasodilation in the gingiva induced by painful tooth-pulp stimulation in sympathectomized human subjects.

This study was designed to determine whether painful electrical stimulation of the tooth pulp induces centrally mediated reflex vasomotor changes in human gingiva and whether the sympathetic nervous system is involved in the vasomotor responses. Dynamic changes in maxillary gingival blood flow (GBF) following painful electrical stimulation of the mandibular lateral incisor were investigated, by means of laser-Doppler flowmetry, in both healthy volunteers and patients undergoing sympathetic blockade for hyperhidrosis. Increases in GBF were observed in both healthy volunteers and patients on the ipsilateral side without an increase in systemic blood pressure, but the evoked GBF increase disappeared when pain sensation was abolished by local anesthetization with 2% xylocaine solution. The vasodilator responses did not differ in amplitude between before and after the sympathectomy. These results suggest that painful tooth stimulation evokes centrally mediated reflex vasodilation, presumably via parasympathetic efferent fibers, in the human gingiva and that sympathetic vasomotor mechanisms are not involved in these responses.