Volatile sulfur compounds (VSC) in mouth air were estimated by gas chromatography. The amount of VSC and the methyl mercaptan/hydrogen sulfide ratio were significantly increased in patients with periodontal disease. These two parameters also increased in proportion to the bleeding index and probing depth. A study was also done on the effect of removal of tongue coating on VSC concentrations in mouth air from patients with periodontal involvement. VSC and the methyl mercaptan/hydrogen sulfide ratio were reduced to 49% and 35%, respectively, by removal of the tongue coating. The average amount of tongue coating removed from patients with periodontal disease was significantly higher than from controls (90.1 mg vs. 14.6 mg, p less than 0.01). Estimated production of VSC from tongue coating was 4 times higher than the control value, and the methyl mercaptan/hydrogen sulfide ratio was also markedly increased. However, a saliva putrefaction study suggested that saliva does not contribute to the elevated ratio of methyl mercaptan in mouth air. These results strongly suggest that, in addition to periodontal pockets, tongue coating has an important role in VSC production, in particular leading to an elevated concentration of methyl mercaptan, which is more pathogenic than hydrogen sulfide.

The amounts of volatile sulfur compounds (VSC) and methyl mercaptan/hydrogen sulfide ratio in mouth air from patients with periodontal involvement were 8 times greater than those of control subjects. Our studies demonstrated that, in patients with periodontal disease: 1) the concentration of disulfide, which is converted to VSC, increased in proportion to the total pocket depth; 2) 60% of the VSC was produced from the tongue surface; 3) the amount of tongue coating was 4 times greater than in control subjects; and 4) VSC production and the methyl mercaptan/hydrogen sulfide ratio of the tongue coating were increased. 2‐Ketobutyrate, which is a byproduct of the metabolism of methionine to methyl mercaptan, was higher in the saliva of patients with periodontal disease. This implies that metabolism of methionine to methyl mercaptan increases in the oral cavity of patients with periodontal pockets. Since free L‐methionine, rather than protein, is the main source for methyl mercaptan, we estimated the methionine supply from the gingival fluid into the oral cavity of patients with periodontal involvement. The results showed that the ratio of methionine to whole free amino acids was significantly higher than that of cysteine. Our studies suggest that not only microorganisms, but also the tongue coating and gingival fluid are factors which enhance VSC production in patients with periodontal disease. J Periodontol 1992; 63:783–789.

The WNT family activates an oncogenic signaling mediated through beta-catenin and is up-regulated in a variety of malignant neoplasms. The signaling translocates beta-catenin into the nucleus and stimulates carcinoma cells in the epithelial-mesenchymal transition (EMT). However, WNT expression and signaling in oral carcinomas have not been examined. The present study focused on unveiling the involvement of WNTs in oral carcinomas, and showed that carcinoma cells express 11 of 19 WNT family members by reverse-transcription/PCR. WNT-expressing carcinoma cells exhibited increased beta-catenin levels in the cytoplasmic pool and translocation to the nucleus. The activation state of signaling correlated with the expression of membrane-type 1 matrix metalloproteinase, which degrades territorial matrices in carcinoma invasion. Immunohistochemistry disclosed that WNT3 expression and nuclear localization of beta-catenin were predominant in carcinoma cells at the invasive front. These results suggest that enhanced WNT expression and signaling accelerate the progression of carcinomas via activating EMTs and local invasiveness.

An acidic protein of human saliva, which we named SAP-1 previously, is now shown to be an inhibitor of several cysteine proteinases. The protein inhibited papain and ficin strongly, and stem bromelain and bovine cathepsin C partially. However, it did not inhibit either porcine cathepsin B or clostripain. The mode of the inhibition of papain was found to be non-competitive. The name cystatin S has been proposed for this salivary protein in view of the similarities in activity and structure to other cysteine proteinase inhibitors such as chicken egg-white cystatin and human cystatins A, B, and C. The cystatin S antigen was detected immunohistochemically in the serous cells of human parotid and submaxillary glands.

Our recent work on the gene structures for human salivary (S-type) cystatins [Saitoh, E. et al. (1987) Gene 61, 329-338] has suggested that the structures of cystatins which we determined previously at the protein level lack N-terminal peptide portions of the full-sized intact forms. In the present study, attempts were made to isolate full-sized S-type cystatins by introducing methanol fractionation into the purification steps to suppress the enzymatic activity present in saliva. Full-sized cystatin SN and two phosphorylated forms of full-sized cystatin S were thus isolated. Analysis of one fraction indicated that this was a mixture of full-sized cystatin SA and non-phosphorylated cystatin S. The phosphorylation sites of cystatin S were determined to be Ser-Ser-Ser1(P)-Lys-Glu-Glu- for monophosphorylated cystatin S and Ser1(P)-Ser-Ser3(P)-Lys-Glu-Glu- for diphosphorylated cystatin S. Immunoblotting analysis with anti-cystatin S antiserum revealed that tears and seminal plasma also contained S-type cystatins, but diphosphorylated cystatin S was detected neither in tears nor in seminal plasma and no cystatin SN was found in seminal plasma. These data indicate that S-type cystatins are secreted into the oral cavity without significant degradation in salivary glands or ducts and that they are expressed tissue specifically.