Recently, allergy to titanium has been reported. However, the patch test reagent for titanium is not standardized yet. The form and density of the patch test reagent for titanium was changed and examined in a group of normal subjects and a group with skin disease. The following conclusions were obtained. 1. A reagent which was composed of pure titanium powder and vaseline was not preferable because its form was a stimulant. 2. If the form of the titanium powder was not sharp even though it was not spherical, it did not cause a stimulated reaction. 3. It is suggested that TiCl4 0.1% is preferable as a patch test reagent for titanium.
It is widely accepted that the sympathetic nerve activity might participate in some mechanisms underlying neuropathic pain which sometimes develops after nerve injuries. Many chemical substances have been proposed to induce pain sensation. Bradykinin (BK) is the most potent in exciting nociceptors and in sensitizing them to thermal and mechanical stimuli. We investigated modulatory effects of sympathetic agents on BK actions in primary afferent dorsal root ganglion (DRG) cells. The present electrophysiological experiments by using the patch clamp technique were conducted to examine the effects of noradrenaline (NA) on BK responses and to determine the sites and mechanism of interaction between them. 1. Small (diameter, 20-35μum) DRG neurons responded to BK with inducing inward currents (BK-responses), but no BK responses could be evoked in DRG neurons larger than 35μm. 2 . NA at 10μM augmented the BK responses in amplitude compared to the control response. 3 . Clonidine at 1μM augmented the BK responses in amplitude, but isoproterenol at 1μM failed to augment the BK responses. 4. After pretreatment with yohimbine, the BK responses were not changed by NA. It is concluded that NA-induced augmentation of the BK actions occurred by activating a 2-adrenergic receptor. Furthermore, this experimental system is a useful model in order to study the cellular mechanisms of neuropathic pain.
Smoking has various influences on oral mucosa, including color change. We quantitatively analyzed color changes of oral mucosa by smoking. To examine the influence of smoking over a wider age range, we measured the color of oral mucosa of 62 nonsmokers and 56 smokers (age 30-83 years) . We measured color with a colorimeter by a perpendicular course, illuminating the measuring sites from a distance of 1 meter by artificial sunlight. Before measuring, we used standard white for calibration. We used the CIE L * a * b * colorimetric system for the color specification. The measured sites were the lips, gingiva, tongue and buccal mucosa. Before colorimetry, we examined the precision and repeatability of colorimeter, but the change was small. Moreover, we similarly examined the sex difference and age difference, but there was no significant difference. This study was approved by the Tokyo Medical and Dental University ethics screening committee. Among nonsmokers and smokers, a statistical difference was recognized in lips L *, a *, gingiva L *, a *, and buccal mucosa L *, b *. Smoking decreased the luminosity of the lips, gingiva, buccal mucosa and caused a blue coloration of gingiva and buccal mucosa.
In this study, we prepared four types of 10-mm-diameter, 10-mm-long, large, columnar, bone powder-impregnated, porous apatite blocks, which did or did not have a single nutrient channel of 1, 2, or 3 mm in diameter in the longaxis direction. We implanted them in the subcutaneous tissue of adult dogs for 4, 8, or 16 weeks, and examined the status of bone formation in each block. As a result, bone formation started with the differentiation of osteoblasts along the wall of macro-pores within an area of dense multinucleated cells, and the area of bone formation consisting of bone along the pore wall and bone marrow in the pores gradually expanded around the block in a ring fashion and inward or outward. In apatite blocks with a 2-or 3-mm nutrient channel, bone formation also proceeded along the channel in the block. At 16 weeks after implantation, even in the middle level, almost the entire porous apatite block with a 3-mm channel became the area of bone formation. However, in other apatite blocks, there remained an area without bone formation ; in particular, in blocks without a nutrient channel or with a 1-mm nutrient channel, there remained an area slightly over 4 mm in diameter without bone formation at the middle level. These findings indicate the importance of the nutrient channel for good bone formation in large blocks.
The purpose of this research was to clarify the structural features of submandibular glands in the elderly. Submandibular glands were removed from 28 cadavers (59-96 years) which dental students had used for anatomy practice. These specimens were fixed again with 10% formaldehyde, and then paraffin sections were made from these specimens according to a general method. After Hematoxylin Eosin, Mason-Goldner, Elastica von Gieson, and Alcian Blue staining had been given, these sections were observed with a light microscope. The specimens of the elderly whom the author had used in this research were divided into two groups of the higher elderly (80 years old or more) and the lower elderly (less than 80 years old) . The results were as follows : 1) Intralobular and interlobular connective tissues increase in the submandibular gland of the higher elderly. 2 ) The epithelial cells of the striated portion become short in the higher elderly. 3 ) As for the epithelial cells of the interlobular ducts, strong Alcian Blue positive reaction is observed in the higher elderly. 4 ) The terminal portion by which a typical form is shown decreases in the higher elderly, and the number of terminal portions decreases, too. In addition, the terminal portion generally becomes small, and the tendency of extension of the glandular cavity is observed. 5 ) In the lower elderly, glandular cells which react to various levels of Alcian Blue exist. Such cells are distributed almost uniformly in the lobules. However, it seems that the Alcian Blue positive cells of the higher elderly decrease. 6) It seems that these structural changes of supportive tissue, duct system, and terminal portion in the submandibular gland of the higher elderly are structural features, suggesting that the secretory function decreases.
The purpose of this study was to elucidate the state of preparation of the dental healthcare system for a large-scale disaster in terms of health-related crisis management by public health centers (PHCs) . Questionnaires were sent by e-mail to 549 PHCs. The response rate was 51.4%. The results showed that the percentage of preparedness for a large-scale disaster was only 26.2% and the dental healthcare system has not been constructed nationwide, especially among PHCs located in areas with smaller populations. The main reasons given for why such a dental healthcare system has not been effectively established were related to lack of concern about such a crisis and a sense that the situation is not critical. Nevertheless, PHCs have made progress in assigning dentists and dental hygienists to the dental healthcare system in preparation for a large-scale disaster.