Interleukin-2 (IL-2) is one of the cytokines regulating antibody formations. To examine the effect of IL-2 on lipopolysaccharide (LPS)-specific antibody secretion on the number of antibody secreting cells (ASC) were counted in the presence and absence of IL-2 in rat spleen cells culture. First we established the enzyme-linked immunospot (ELISPOT) assay, which is the method of determinating the number of ASC. Rat spleen cells with high and low concentrations of LPS (10 ng/ml and 10μg/ml) were incubated for 3 days in vitro, and the number of the LPS specific ASC were counted. In the culture incubated with high concentration (LPS 10 ng/ml) the number of ASC is higher than that in the culture with low concentration LPS 10μg/ml, it is obious that the appearance of ASC depended on LPS concentrations. Supprisingly addition of IL-2 decreases the number of ASC at low concentration of LPS (10 ng/ml), but it increases that at high concentration of LPS (10μg/ml). Thus opposite effect of IL-2 was observed at different LPS concentrations. It is well-known that IL-2 enhances antibody formation in the presence of antigen. But it is strange that IL-2 suppressed antibody formation in the presence of antigen, in the case of low concentration of LPS.

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A consciousness survey concerning the demand for and supply of dental care was conducted among the inhabitants in Nagasaki city having an excess of dentists, in Takashima-cho having no dentist and in Sasebo city which is the intermediate type between the above two areas. As a result, the inhabitants in Nagasaki city were quantitatively satisfied with the provision of dental care, while there was an extremely high demand for the care in Takashima-cho. In Sasebo city, the degree of satisfaction with the dental care tended to be the same as that in Nagasaki city.

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Stress analysis was carried out for Class V composite resin restoration models to estimate stresses induced in enamel by polymerization shrinkage of the composite, using a finite element method. For all the models used, tensile stress was concentrated in both incisal side and cervical side marginal enamel near the interface between the composite and enamel. For a butt-jointed model showing good bonding between the composite and dentin, the peak stress in the enamel was found near the cervical side margin. For a model showing a gap between the composite and dentin, on the other hand, tensile stresses in both marginal enamel were higher than those of the model with good bonding, and especially the tendency being marked in the incisal side enamel. Thus the peak stress in the marginal enamel by polymerization shrinkage was reduced by giving bonding between the composite and dentin, using a composite with the elastic modulus being at lower level or as higher as that of enamel, giving a beve! at the cavity margin, and lining the cavity thicker with a material having lower elastic modulus. It suggests that the application of such techniques for Class V composite resin restorations may effectively decrease the occurrence of cracks in the marginal enamel during polymerization of the composite.

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Two protein quantitation methods for measurement of cell growth in tissue culture were examined on their utility by using L 929 cell line. One was a modified Lowry method using a phenol reagent, and the other was the Dye binding assay method described by Bradford. The range of cell protein measurement was found to be enough to use and a little wider by the modified Lowry method than by the Dye binding assay method ; 5∿100μg by the former and 5∿60μg by the latter. The calculated factor to convert bovine serum albumin standard equivalent (μg) to cell count was 2.0×10^3 cells by the modified Lowry method, and 2.8×10^3 cells by the Dye binding assay method. Furthermore, those two methods were compared with other two methods to which protein quantitation technique was not applied ; one was nucleus counting through a microscope, and the other was a kind of colorimetric determination of the stained cell layer with Monocellater. Both of the protein quantitation methods were confirmed to give much less amount of scatter in measured values than nucleus counting or than the method with Monocellater.

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In tooth preparation, the heat generation by cutting may cause injury to the pulp as well as severe discomfort to the patient. In this study, in vitro measurements of the temperature changes in the pulp chamber during cutting were performed on extracted human incisors. The tooth was cut inward from its labial surface with an air-turbine handpiece under each combination of the conditions of (1) cutting load : 20, 50 and 80 g ; (2) grit size of diamond bur : coarse, regular and fine ; and (3) water spray : 0, 1 and 5 ml/min. When the cutting load was small, the temperature rise of the pulp chamber was small and the temperature rather decreased by water spray. As the cutting load increased, the temperature of the pulp chamber increased ; however, the increment varied according to the interaction of the load and the amount of water. No significant differences were found in the temperature change between the coarse and regular grit sizes of the diamond bur used, while the temperature rise was minimum with the grit size of the bur.

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Eighty-four pediatric patients, out of the 195 patients diagnosed as mucous cyst and who visited our clinic between 1987 and 1990, were clinically and histopathologically analysed. 1) Pediatric patients diagnosed as mucous cyst numbered 84 children, which is 43.1% of all of the 195 patients. 2) Male/female ratio was 1 : 1.4 in all of our patients, whereas 1 : 1.9 in children, and 1 : 2.6 in patients under 10 years of age. Female patients were more than male in children. 3) The lesion in the majority of pediatric patients was located on the lower lip but occurred with lesser frequency on the tongue, the floor of the mouth, and other regions. 4) All cases were found histopathologically to be of the three types (Matsuoka's classification) ; the type I was 28.7%, the type II 69.7%, and the type III 1.5%. As to pediatric patients, type I was 38.1%, the type II 60.7%, and the type III 1.2%. 5) Treatment was mostly surgical removal in children as well as in adults. 6) The recurrence of the lesion was found in only 3 cases (3.5%) in children.

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A case of secondary syphilis in a 27-year-old female only eruption with oral mucosa is presented. She complained of soreness of the oral and pharyngeal mucosa. She had only the slightly elevated grayish membranous inflammatory lesion, so called plaques opalines, on the tongue, palate and fauces. It is considered to be a typical oral menifestation of secondary syphilis but without other skin lesions at this stage of the disease for her. It is difficult to diagnose syphilitic lesion of the oral cavity without other skin or pudendal lesions. So any clinician must pay more attention to the grayish or erythematous eruptic lesion of unknown origin in the oral cavity.

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A dental magnetic attachment is small enough and provides relatively high retentive force to be used in removable prostheses. It consists of a magnetic assembly and a magnetizable metal commonly reffered to as a keeper. Although this attachment possesses many advantages compared to the conventional mechanical attachment, problems with corrosion can significantly affect the useful life span of magnet. This study describes 8 patients with 11 units of a new magnetic attachment which has a higher attractive force and perfect resistance against corrosion. The higher attractive force made the removable prosthesis more stable and the loss of magnetism was not found at all. Tarnish and corrosion except for the dental plaque were not found in any case. Therefore all patients have been satisfied up to date. This new dental magnetic attachment may be viable alternative for the intraoral retention of removable prostheses.

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This study shows that crown and bridge using double crown system can be retained for five years in good state. The double crown we have devised can minimize the elevation of the internal crown at the margin, because it has open occlusal plane. As the double crown properly reproduces emergence profile and tooth contour, it can facilitate the convenience and effectiveness of oral hygiene procedures. The double crown system can be practiced in cases where the abutment tooth of the bridge is not with parallel each other.

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Cementifying fibroma is a rare neoplasm of the bone, and it is composed of celluler fibrous connective tissue containing variable quantities of cementum. The clinical appearance is typical of any slow-growing odontogenic tumor. Either jaw may be involved, but there appears to be a marked predilection for the mandible. The tumor is more common in young and middle-aged adults. Furthermore, there is a marked predilection for occurrence in females. We experienced a case of cementifying fibroma in the right upper molar region, and report on it with some comments based on the literature. The patiant was a 55-year-old woman. Clinically, mild and diffuse swellings were observed of the right upper molar region. Radiographic examination revealed diffuse mottled radiopaque lesions in the right maxilla. The tumor was surgically removed. Microscopically, the tumor was composed of delicate interlacing collagen fibers, interpersed with large numbers of cellular elements and cementum-like hard tissues. It was diagnosed as cementifying fibroma. The prognosis is fairly good after surgical treatment and there is no recurrence after 4 years and six months.

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Castleman's lymphoma usually occurs in the medistinum and it is relatively rare to occur in the head and neck region. Histopathologically, it is characterized by hyperplasia of lymphoid tissue with follicles, hyalinized blood vessels, and some of its follicles resemble Hassal's corpuscles of the thymus. Recently, we experienced a case of Castleman's lymphoma occurring in the submandibular region of a 25-year-old male patient. Clinically, the tumor was suspected of a pleomorphic adenoma, but the histopathological diagnosis was Castleman's lymphoma, hyaline-vascular type. The prognosis is fairly good after surgical treatment and there is no recurrence at present. We reported on it with some comments based on the literature.

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