Genetic epidemiology of tooth agenesis in Japan: a population- and family-based study.

Tooth agenesis is one of the most common congenital anomalies in humans. However, the etiology of tooth agenesis remains largely unclear, as well as evidence base useful for genetic counseling. Therefore, we estimated the prevalence and sibling recurrence risk, and investigated agenetic patterns systematically. Tooth agenesis was classified into two subtypes: hypodontia (one to five missing teeth) and oligodontia (six or more missing teeth). The prevalence of these two subtypes were 6.8% [95% confidence interval (CI): 6.1-7.7%] and 0.1% (95% CI: 0.04-0.3%), respectively, and sibling recurrence risk of these were 24.5% (95% CI: 13.8-38.3%) and 43.8% (95% CI: 26.4-62.3%), respectively. This result suggests that the severe phenotype, oligodontia, might be mostly transmitted in a dominant fashion. Using a simple statistical modeling approach, our data were found to be consistent with a bilateral symmetry model, meaning that there was equal probability of missing teeth from the right and left sides.

Whitening Efficacy of Chewing Gum Containing Sodium Metaphosphate on Coffee Stain: Placebo-controlled, Double-blind In Situ Examination.

This study aimed to evaluate the ability of chewing gum containing sodium metaphosphate (SMP) to remove coffee stains from enamel in situ. This was a double-blind (subjects, evaluators), parallel-group, crossover, randomized clinical trial with 30 healthy adult volunteers. Each participant held an appliance with a hydroxyapatite (HA) pellet on the lower lingual side of his or her mouth for two hours to allow pellicle formation. The appliances were subsequently immersed in coffee solution at 37°C for 48 hours. The color of the HA pellet before and after coffee immersion was measured using a spectrophotometer. The participant set the appliance and chewed two pieces of test gum, which contained 7.5 mg of SMP per piece, or control gum without SMP. Each cycle included five minutes of exposure to chewing gum, after which the appliances were placed in 100% relative humidity at room temperature for a 30-minute incubation. This cycle was repeated five times for each gum type. The color of the HA pellet was measured after each chewing cycle using the spectrophotometer. In addition, ΔE* values, which indicate the change in pellet color after each chewing cycle compared with after coffee immersion, were calculated. Data were analyzed using the paired t-test with Bonferroni adjustment to compare ΔE* values of control and test gum after each chewing cycle. The ΔE* values of test gum were significantly higher than those of control gum after all chewing cycles, excluding the first cycle (p<0.05). This finding indicates that test gum containing SMP was more effective at removing coffee stains from the HA pellet than control gum. We conclude that chewing gum containing SMP can effectively remove coffee stains from HA pellets. Thus, SMP is a promising agent to be further explored in tooth-cleaning studies.

A review of recent unexpected animal disease events in Japan and Korea and the follow-up action taken.

In Japan, the need to improve countermeasures against biological weapons was recognised after the Aum Shinrikyo cult attempted to use biological weapons in 1995. This paper describes how the two relevant ministries in Japan worked together to cope with recent disease outbreaks, including cases of classical swine fever (CSF) and avian influenza, which evidence suggests might have been the result of the deliberate misuse of unauthorised vaccines that had been illegally imported. By implementing successful control measures the two ministries were able to eradicate all the diseases within very short periods. In the past few years, the Republic of Korea has also experienced outbreaks of foot and mouth disease, highly pathogenic avian influenza, and CSF, all of which had previously been absent (or had been eradicated) in Korea. A review of the historical background, major events of the outbreaks and the control measures which were implemented are presented here.

State of association of band 3 protein from bovine erythrocyte membrane in nonionic detergent.

The state of association of bovine Band 3, which is a major intrinsic protein of erythrocyte membranes, was examined in nonaethyleneglycol dodecyl ether (C12E9) solution by ultracentrifugation, gel filtration, gel electrophoresis and cross-linking studies. The molecular weight of bovine Band 3 was 107,000 +/- 5% as determined by gel electrophoresis in the presence of sodium dodecyl sulfate. When Band 3 was purified in C12E9 solution with the aid of 2,3-dimethylmaleic anhydride (DMMA), which is a known dissociating reagent for peripheral proteins from erythrocyte membranes and for Band 3-Band 4.2 complex, the protein was present as a monomer and was not oxidatively cross-linked. On the other hand, DMMA-untreated Band 3 was present as oligomeric forms composed mainly of the dimer and tetramer, and the oligomer in C12E9 was a susceptible to oxidative cross-linking as Band 3 in ghosts. The oligomeric form apparently retained a more ordered conformational state than the monomeric form. These results indicate that the bovine Band 3 oligomer is a stable form in C12E9, but the present result showing the coexistence of dimer and tetramer in C12E9 contrasts with the reported observation that human Band 3 is present as a stable dimer in a nonionic detergent, Triton X-100. It was shown that polyacrylamide gradient gel electrophoresis in the presence of C12E9 gave better resolution of the associated species of Band 3 than ultracentrifugation or gel filtration, and this method made it possible to determine the Stokes radii of Band 3-C12E9 complexes. This result suggests the usefulness of electrophoretic methods in the presence of nonionic detergent for studies of the state of association of other membrane proteins.

Three-phase bone scintigraphy and viability of vascularized bone grafts for mandibular reconstruction.

Three-phase bone scintigraphy was undertaken to check the anastomotic patency and monitor the viability of vascularized bone grafts. Ten consecutive patients who underwent vascularized bone grafting of the mandible were reviewed. A successful clinical outcome was achieved in 8 patients. The graft failed in 2 patients. In this series, 3-phase bone scintigraphy of radiolabeled (99m)Tc-methylene-diphosphonate was performed at 7 days, and at 1, 3, 6, and 12 months after reconstruction. Assessments made using 3-phase bone images were compared with the clinical findings. The clinical outcome of the cases presented in our series correlated extremely well with 3-phase bone images. Three-phase bone scintigraphy is a useful method for the assessment of patency and viability of vascularized bone grafts. The use of this method can be very helpful in assessing the anastomotic patency and viability of a graft which for clinical reasons is suspected of being non-viable.

An evaluation of neck dissection in carcinoma of the tongue.

Forty-six neck dissection cases were performed out of 117 cases of tongue cancer occurring from 1973-1981 at the Gunma Cancer Center. Among the 47 cases, 27 were initially treated surgically. In 14 cases radium therapy was used for the primary lesion and was followed by neck dissection. In another 13 cases hemiglossectomy and neck dissection were performed together. In addition, in 19 cases neck dissection was performed as secondary treatment for metastatic nodes or for recurrence of the primary lesion following radium therapy. In the cases of neck dissection performed as initial treatment along with hemiglossectomy, 84.6% had a two-year survival rate. Neck dissection performed as a secondary treatment resulted in a 46.7% survival rate over 3 years. It is evident from these figures that neck dissection performed as initial treatment results in better prognosis for the patients. In cases where metastatic nodes are present or suspected, neck dissection and hemiglossectomy should be undertaken.

Effect of culture matrix on newborn rat skin basal cells; modification of cell response to extracellular calcium.

Basal cells from newborn rat skin epidermis were cultured on various culture matrixes, and the response of the cells to extracellular calcium was examined. When the cells were cultured on a type I collagen-coated Millipore filter to maintain clearance under the cultured cells as intact skin, the cells responded to a fluctuation in extracellular calcium and were detached from the collagen layer in a high calcium environment. In this case, protein synthesis of the cells increased calcium-dependently. In contrast, calcium-dependent protein synthesis of the cells was not detected in culture, neither on the plastic plate nor the type I collagen-coated plate. Moreover, in culture on a type I collagen-coated filter, the size of basal cells was unchanged for 2 d. This should be consistent with the fact that morphological changes in cells are very gradual in vivo. On the other hand, when basal cells were cultured either on a plastic plate or collagen-coated plate, the cells lost their normality; they were markedly enlarged for 2d of culture. Thus, the responses of skin basal cells to extracellular calcium fluctuated according to the types of culture matrixes. In this case, keratin synthesis and a morphological change of the cells seems to be concerned with the clearance, which was established in the basal side of the cultured basal cells as intact skin.

Effects of biscoclaurine alkaloid cepharanthine on newborn rat skin epidermal and dermal cells.

Effects of biscoclaurine alkaloid cepharanthine on proliferation of skin cells were examined in vitro. The alkaloid was found to enhance attachment and cell layer formation of newborn rat skin epidermal cells in culture on type I collagen-coated Millipore filter, and to potentiate production of keratins in these cells. Spreading and growth of skin dermal fibroblasts were inhibited by cepharanthine in a dose-dependent manner, but the alkaloid-treated cells still retained the ability to synthesize type IV collagen. In culture of skin cells containing both epidermal and dermal cells, no growth of epidermal cells or over-growth of dermal fibroblasts was observed in medium without cepharanthine. In contrast, the presence of the alkaloid suppressed the growth of fibroblasts and promoted the formation of epidermal cell layers accompanied by production of keratins. Thus, in comparison with the cells untreated with the alkaloid, cepharanthine-treated skin epidermal and dermal cells in vitro expressed in vivo-like characters.