Altered Rheological Properties of Saliva with Aging in Mouse Sublingual Gland.

Mucin in saliva plays a critical role in the hydration and lubrication of the oral mucosa by retaining water molecules, and its impaired function may be associated with hyposalivation-independent xerostomia. Age-dependent effects on salivary gland function and rheological properties of secreted saliva are not fully understood as aging is a complex and multifactorial process. We aimed to evaluate age-related changes in the rheological properties of saliva and elucidate the underlying mechanism. We performed ex vivo submandibular gland (SMG) and sublingual gland (SLG) perfusion experiments to collect saliva from isolated glands of young (12 wk old) and aged (27 mo old) female C57BL/6J mice and investigate the rheological properties by determining the spinnbarkeit (viscoelasticity). While fluid secretion was comparable in SMG and SLG of both mice, spinnbarkeit showed a significant decrease in SLG saliva of aged mice than that of young mice. There were no significant differences in GalNAc concentration between young and aged SLG saliva. Liquid chromatography/tandem mass spectrometry analysis of SLG saliva revealed that (Hex)1 (HexNAc)1 (NeuAc)1 at m/z 793.31 was the most abundant O-glycan structure in SLG saliva commonly detected in both mice. Lectin staining of salivary gland tissue showed that SLG stained strongly with Maackia amurensis lectin II (MAL II) while Sambucus nigra agglutinin (SNA) stained little, if any, SLG. The messenger RNA expression of St3gal1 that encodes an α-2,3 sialic acid sialyltransferase SIAT4-A showed a decrease in SLG of aged mice, confirmed by a Western blot analysis. Lectin blot analysis in SLG saliva revealed that the relative signal intensity detected by MAL II was significantly lower in aged SLG. Our results suggest that spinnbarkeit decreases in SLG of aging mice due to downregulation of sialic acid linked to α-2,3 sialic acid sialyltransferase expression.

Endothelin-1 Elicits TRP-Mediated Pain in an Acid-Induced Oral Ulcer Model.

Oral ulcer is the most common oral disease and leads to pain during meals and speaking, reducing the quality of life of patients. Recent evidence using animal models suggests that oral ulcers induce cyclooxygenase-dependent spontaneous pain and cyclooxygenase-independent mechanical allodynia. Endothelin-1 is upregulated in oral mucosal inflammation, although it has not been shown to induce pain in oral ulcers. In the present study, we investigated the involvement of endothelin-1 signaling with oral ulcer-induced pain using our proprietary assay system in conscious rats. Endothelin-1 was significantly upregulated in oral ulcers experimentally induced by topical acetic acid treatment, while endothelin-1 production was suppressed by antibacterial pretreatment. Spontaneous nociceptive behavior in oral ulcer model rats was inhibited by swab applications of BQ-788 (ETB receptor antagonist), ONO-8711 (prostanoid receptor EP1 antagonist), and HC-030031 (TRPA1 antagonist). Prostaglandin E2 production in the ulcers was suppressed by BQ-788. Mechanical allodynia in the model was inhibited not only by BQ-788 and HC-030031 but also by BQ-123 (ETA receptor antagonist), SB-366791 (TRPV1 antagonist), and RN-1734 (TRPV4 antagonist). In naive rats, submucosal injection of endothelin-1 caused mechanical allodynia that was sensitive to HC-030031 and SB-366791 but not to RN-1734. These results suggest that endothelin-1 production following oral bacterial invasion via ulcerative regions elicits TRPA1-mediated spontaneous pain. This pain likely occurs through an indirect route that involves ETB receptor-accelerated prostanoid production. Endothelin-1 elicits directly TRPA1- and TRPV1-mediated mechanical allodynia via both ETA and ETB receptors on nociceptive fibers. The TRPV4-mediated allodynia component seems to be independent of endothelin signaling. These findings highlight the potential of endothelin signaling blockers as effective analgesic approaches for oral ulcer patients.

Primary intra-osseous carcinoma of the maxilla.

An unusual case of maxillary carcinoma, diagnosed as a primary intra-osseous carcinoma, is reported. This was differentiated from primary carcinoma of the maxillary sinus on the basis of the radiographic findings and the patient's dental history.

A method for the repair of transverse facial clefts.

In the natural form of the oral commissure, the outer edges of the upper and lower lips form small triangular flaps. The white line of the lip at the commissure is web continuous with the upper and lower red lips. The lower part of this web is larger than the upper. To repair this so that there is a natural appearance, a Z-plasty and mucocutaneous flap based inferiorly is performed on the transverse facial cleft. The incision line for the Z-plasty is made though each vermilion border and is extended approximately 1.5-2 mm to create the web continuous with red lips. The mucocutaneous flap is formed when making the incision through the lower vermilion border. As the flap is elevated and sutured to the upper lip, the larger web-like skin on the lower lip is made. This skin is seen to insert boldly into the oral cavity.