Polymorphism of genes encoding toll-like receptors and inflammatory cytokines in periodontal disease in the Japanese population.

Periodontitis, which is a widespread and major dental disease, is a multifactorial, lifestyle-related disease and has been analyzed for gene polymorphism. We examined the frequency of the polymorphisms of the pro-inflammatory cytokine genes IL-1 A (-889) and IL-1 B (+3953) in relation to periodontitis in the Japanese population. We also examined whether polymorphism of TLR2 (Arg677Trp) and TLR4 (Asp299Gly), which are receptors recognized by periodontopathic bacteria, may also be associated with periodontitis. The subjects were 92 Japanese individuals, among whom 43 had periodontitis and 49 were healthy controls. We isolated genomic DNA from lingual mucosal cells and tested them for single nucleotide polymorphisms by polymerase chain reaction-restriction fragment length polymorphism. The incidence of polymorphisms was analyzed statistically by Fisher's exact test, and the sensitivity and specificity of the gene polymorphisms were calculated. The purpose was to determine whether such polymorphisms might be effectively used in the diagnosis of periodontitis. However, we found no evidence that the gene polymorphism of IL-1A (p = 0.082), IL-1 B (p = 0.180), TLR2 (p = 1.000) or TLR4 (p = 1.000) and overall gene polymorphism in any of the genes (p = 0.752) correlate with periodontitis. The sensitivity (14.0%) and specificity (83.7%) of the mutations found in all of the genes were low. Therefore, we advise against using the analyses of polymorphism of these genes to detect periodontitis in the Japanese population.

Recovery of genomic DNA from lingual mucosal cells in sufficient quantity and quality.

PURPOSE: To investigate whether genomic DNA can be purified in sufficient quantity and quality from the oral cavity. METHODS: One milliliter of peripheral blood and saliva were collected. The buccal and lingual mucosal cells were also obtained using 10 strokes with a swab or a toothbrush, respectively. All materials were centrifuged and the cells were lysed by adding sodium dodecyl-sulfate and proteinase K. The DNAs were extracted with phenol and precipitated with ethanol followed by electrophoresing on 0.8% agarose gel. The purified DNAs were digested with restriction enzyme Dpn I and Mbo I, respectively. Amplification of the IL-1A gene by PCR was carried out using the purified DNAs and electrophoresing on polyacrylamide gel. RESULTS: DNA was obtained from lingual mucosal cells collected with a toothbrush. Only about one-thirtieth of the recovered DNA was of non-human origin (bacterial contaminants from the oral cavity). Judging from the PCR amplifications of the IL-1A gene, the DNA extracted from lingual cells was of sufficient quality, in all respects indistinguishable from the DNAs extracted from the other specimen, such as peripheral blood, saliva and buccal mucosal cells collected with a swab, and in sufficient quantity. Our results indicate that it is possible to purify DNAs from lingual mucosal cells collected with a toothbrush in a simple and safe manner. Compared to DNA samples from patients by blood extraction, the described method also had the advantage of being painless and not inducing mental distress.

Assembling nanowires from Mo-S clusters and effects of iodine doping on electronic structure.

Using ab initio calculations, we find high stability of octahedral Mo6S8 clusters, which can further be condensed to form Mo3nS3n+2 (n, an integer) nanowires. These linear structures are energetically more favorable compared with other closed-packed polyhedral isomers of Mo-S clusters. The octahedral units in nanowires are stabilized by strong Mo-Mo interactions and p-d hybridization between Mo 4d and S 2p orbitals. There is a free electron-like band that crosses the Fermi energy in infinite nanowires and leads to their metallic character. Iodine doping acts as electron donor and can be used to tailor the electronic conductivity. For Mo12S8I4 nanowires, both electrons and holes are found to contribute to conduction. These nanowires are energetically more favorable than the experimentally obtained Mo12S6I12 nanowires.

Ab initio study of structural stability of Mo-S clusters and size specific stoichiometries of magic clusters.

Using first-principles calculations with ultrasoft pseudopotential formalism and the generalized gradient approximation for the exchange-correlation functional, we study the stability of MonSm (n =1-6 and m ranging from n to 3n) clusters and obtain the optimal stoichiometry for each n corresponding to the magic cluster. It is found that in this size range, the lowest-energy structures favor a core of metal atoms, which is covered by sulfur. In particular, we observe that for Mo6S14 isolated clusters, a 3D structure is significantly lower in energy as compared to platelet structures found recently on Au (111) surface. The composition ratio between S and Mo in the magic clusters is less than 2 for n=3 and greater than 2 for n<3. The structural stability of the magic clusters arises from the optimization of the Mo-Mo and Mo- S bonding as well as the symmetry of the cluster. Addition of a terminal sulfur in a magic cluster generally lowers its binding energy. The presence of partially occupied d-orbitals in Mo atoms contributes to Mo-Mo bonding and for higher S concentration it leads to sulfur-sulfur bond formation. The variation in energy due to a change in the sulfur composition suggests that sulfurization of the magic clusters is generally more favorable than desulfurization.

[Correlation between periodontal disease and osteoporosis using panoramic radiographic parameters for diagnosed osteoporosis in dental clinic].

The correlation between periodontal disease and osteoporosis was evaluated by comparing age, panoramic radiographic and clinical parameters of periodontal disease. Diagnosis of osteoporosis in periodontal diseased patients was evaluated by panoramic radiographic parameters (mandibular cortical width:MCW). Subjects which had more than 20 teeth and examined by panoramic radiography were untreated adults with periodontal disease who were free of other systemic disease. The following parameters were examined on panoramic X-ray film:alveolar bone loss (ABL), mandibular bone mass with the use of mandibular cortical width (MCW). ABL was significantly higher and MCW significantly lower in the postmenopausal group (>6 years after menopause). The number of teeth was significantly lower and CAL significantly higher in the postmenopausal group (>11 years after menopause). Age and ABL correlated positively in men and women. Years after menopause and ABL and MCW and CAL in the postmenopausal group were correlated positively. Women whose MCW was less than mean - 2 SD should be diagnosed with osteoporosis. Our results demonstrated that periodontal disease correlates with osteoporosis, and MCW could be useful in detecting of osteoporosis in women with periodontal disease.