We isolated a hemagglutinin from Prevotella nigrescens strain E 4 by mechanical shearing, ultrasonication and gel filtration. Hemagglutinating activity was eluted in the fractions following the first and second peaks on a Sepharose CL-4 B column. The Ouchterlony method revealed that both active fractions react with IgG against a purified hemagglutinin from non-fimbriated Prevotella intermedia strain E 18 (E 18 HA). The precipitating line between first active fraction and anti-E 18 HA IgG was located in the center of the wells, although the line between E 4 HA and anti-E 18 HA IgG was located on the side of the antibody. In a previous report, we disclosed that Prevotella intermedia ATCC 15032 possess a strong hemagglutinating activity, but do not show precipitation with E 18 HA antiserum, while Prevotella nigrescens strains P 43 and P 77 do not show hemagglutinating activity and precipitation with E 18 HA IgG. Therefore, Prevotella intermedia ATCC 15032, Prevotella nigrescens strains P 43 and p 77 cells were harvested, mechanically sheared, sonicated, and reacted with E 18 HA IgG. We found a common antigen between E 18 HA and Prevotella intermedia ATCC 15032 cells, but not in Prevotella nigrescens strains P 43 and P 77. We obtained a single band at approximately 40k Da when we applied the second peak (designated E 4 HA) to SDS-PAGE. Western blotting produced a single band corresponding to those from SDS-PAGE. The activity was sensitive to trypsin, chymotrypsin, protease, β-glucosidase and various detergents, but resistant to heat at 80°C for 10 min. Addition of _L-arginine and _L-lysine caused hemagglutination inhibition, although addition of _L-fucose, _L-rhamnose and maltose increased the activity.
These results indicate that this hemagglutinin is a protein-polysaccharide complex in nature and is distributed on most of the cell surface of Prevotella intermedia and Prevotella nigrescens. Shika Igaku (J Osaka Odontol Soc) 1996 Jun; 59(2): 127-136.

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We examined and characterized β-hemolytic activity in 92 strains of Prevotella intermedia and 40 strains of Prevotella nigrescens isolated from periodontal pockets, periapical pathosis, cellulitis and oral flora. More than 94% of the strains tested exhibited hemolytic activity on horse blood agar plates, while 100% of Prevotella intermedia and 80% of Prevotella nigrescens strains showed a positive reaction on human blood agar plates. Hemolytic activity of the test strains increased with increases in cell concentration, suggesting a specific surface interaction. Long incubation of the bacterial cells produced strong activity. Unlike the results of Beem et al., hemolytic activities in some strains of Prevotella intermedia and Prevotella nigrescens increased with treatment by heat, trypsin, chymotrypsin and protease, while that of many strains decreased with lysozyme.
We also attempted to isolate a hemolysin from Prevotella nigrescens strain E 4, which has a hemagglutinating activity, by mechanical shearing, ammonium sulfate precipitation, ultrasonication, centrifugation at 35,000 rpm for 2 h, and gel filtration. E 4 hemolysin activity was found in the supernatant with centrifugation at 35,000 rpm for 2 h and in the first peak on a Sepharose CL-4 B column equilibrated with phosphate buffered saline, indicating that this hemolysin is different from the hemagglutinin that was found in the third peak. E 4 hemolysin was sensitive to heat and chymotrypsin.
These results collectively suggest that hemolytic factors exist throughout the cell surface of Prevotella intermedia and Prevotella nigrescens strains, indicating that both species may aggregate with erythrocytes in vivo, hemolyze and utilize hemoglobin for their growth. Shika Igaku (J Osaka Odontol Soc) 1996 Jun; 59(2): 137-145.

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We did a clinicopathologically survey on 27 patients treated for parotid tumors. Echography and sialography yielded a diagnostic accuracy of 82 to 89 percent. These methods were more useful in the preoperative diagnoses of malignancy than RI-scintigraphy (^99mTc, ⁶⁷Ga). Echography should be the first choice for imaging tumors because it is simple. Computed tomography (sialo-CT) is most useful for locating the tumor.
Under the histological classification of the World Health Organization (1991), 21 of the 27 cases were benign, and 6 were malignant. The most prevalent tumor among the benign lesions was 17 cases of pleomorphic adenoma.
Four of the pleomorphic adenoma cases represented a histologically distinct group of tumors, different from benign and malignant lesions. We referred to these lesions as intermediate, semi-malignant tumors. Cellar atypism and capsular invasion in the histological findings were deemed important criteria for diagnosis of this intermediate type. Pleomorphic adenoma of the intermediate type has the potential for malignant change, and should therefore be followed closely. Shika Igaku (J Osaka Odontol Soc) 1996 Jun; 59(2): 146-158.

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We investigated the need for controlling the force and duration of occlusion when making silicone-black contact impressions. We checked the influence of axial forces on occlusal contact by measuring the contact area of 7 volunters. A variety of forces, maximum clenching for 1 min and medium clenching for 1 and 5 min, were applied as axial force to the maxillary first molars. The occlusal contact area decreased significantly after maximum clenching for 1 min and medium clenching for 5 min. However, there was no change in occlusal contact area with medium clenching for 1 min.
These findings suggest that axial forces are very important in occlusal examinations. Shika lgaku（J Osaka Odontol Soc 1996 Jun; 59(2): 159− 168.

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We investigated fluoride reaction products occurring on the surface of tooth enamel by using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (ESCA). The surface of human dental enamel was polished by standard methods and then treated with an acid phosphate fluoride solution (APF; 9,000 ppm F, pH 3.4) for 4 min at room temperature. After fluoride treatment, the surface was washed with 1M KOH for 3 or 24 h.
AFM images indicated a large amount of globular material on the surface of the APF-treated enamel. After KOH wash for 24 h, this material was eliminated from the surface. Elimination of this material permitted detection of apatite crystals on the surface.
The F/Ca and Ca/P ratios during ESCA analysis indicated the presence of calcium fluoride containing phosphate on the surface of APF-treated enamel. However, after 24 h of KOH wash, these ratios were altered, indicating the presence of fluorapatite.
These results indicate that the materials produced by APF treatment were calcium fluoride containing phosphate. After the materials were dissolved with KOH wash, florapatite might have formed on the enamel surface. Shika Igaku (J Osaka Odontol Soc) 1996 Jun; 59(2): 169-178.

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We investigated factors affecting the zeta potential of mutans streptococci, and how changes in zeta potential influence surface potential energy. Zeta potential of nine species of mutans streptococci were measured in phosphate buffer solutions of various pH and ion strengths. The strength of adsorption of bacteria to hydroxyapatite was measured as the maximum surface potential energy (V_max), while the broth dilution method was used to measure minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).
Zeta potential of the bacteria was related to serotype and growth speed and was very dependent on pH and ion strength. It had a greater negative value with PO₄^3- and a smaller negative value with F^-, Al³⁺, Sn⁴⁺ and chlorhexidine. Results for MIC and MBC indicated that NaF and chlorhexidine produced changes in zeta potential for different reasons than did other chemicals. Although the Vmax between hydroxyapatite and bacteria with high zeta potential was influenced by pH, ion strength, and the presence of F^-, Al³⁺, Sn⁴⁺ and chlorhexidine, the Vmax between hydroxyapatite and bacteria with lower zeta potential was influenced only by ion strength.
We found that the zeta potential of mutans streptococci was affected by pH, ion strength and the presence of multivalent cations. This suggests that adhesion of bacteria to hydroxyapatite can be inhibited by increasing pH, decreasing ion concentration, and not incorporating multivalent cations in the solution. Shika lgaku (J Osaka Odontol Soc) 1996 Jun; 59{2): 179-192.

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I investigated the surface characterizations of apatite plates synthesized on glass by the method of Abe, and of commercially available sintered apatite plates, and examined adsorption isotherms of protein to these materials. Although X-ray diffraction indicated that the sintered apatite had high crystallinity, the peak diffraction strength of the synthesized material was weak. Electron scanning chemical analysis of the surface showed that the peaks for calcium, phosphorus, oxygen and carbon for both apatite materials were located in the same positions as for powdered synthetic hydroxyapatite. Observation by scanning electron microscopy and atomic microscopy indicated that the surface of the sintered apatite was flat as a result of polishing, while that of the synthesized apatite had overlapping layers. The zeta potential for both materials was the same as that for powdered synthetic hydroxyapatite when measured in phosphate buffer solution at pH 5.0, 6.0 and 7.0. The contact angle of sintered and syhthetic plate (69.6 and 63.5) were similar to that of human dental enamel. The zeta potential of the surface of synthesized apatite plate in protein solution (human serum albumin and salmon protamine) increased with increases in protein concentration. The plateau value of the zeta potential of sintered and synthetic apatite plates were more faster to the charge of protein than that of synthetic hydroxyapatite. I found that apatite plate used was useful for experiment on the adhesion of protein and bacteria. Shika Igaku (J Osaka Odontol Soc) 1996 Jun; 59(2): 193-201.

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We used the finite element method to compare the mechanical behavior in bone around IMZ implants when the implants were splinted to teeth and when they were free-standing. Muscle activity of the masseter, anterior temporal and anterior belly of the digastric muscles was evaluated by electromyographic linear envelops (EMG profiles). Deflection and stresses generated in bone around the implant and on the surface of the implant were less when it was splinted than when not. Regardless of whether the implants and teeth were splinted, EMG profiles of the masticatory muscles varied with each chewing stroke before placement of the super-structures, although they were stable after placement. These findings suggest that splinting IMZ implants to natural teeth poses little risk mechanically and functionally. Shika Igaku (J Osaka Odontol Soc) 1996 Jun; 59(2): 202-220.

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Apoptosis, unlike necrosis, signifies programmed cell death. It is observed during the developmental process or with cell turnover. DNA fragmentation occurs in cells with apoptosis. Although this phenomenon is said to be inhibited in cancer cells, it may not be in benign neoplasms. We studied DNA fragmentation using the terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling method to elucidate apoptosis in pleomorphic adenoma. Although few cells were apoptosis-positive in the portion showing proliferation of epithelium in sheets, many were positive in the area showing myxoid or ductal structures. On the other hand, many apoptosis-positive cells were observed in ductal epithelial cells of the normal minor salivary gland, although few positive cells were seen in the acinus. This suggests that apoptosis tends to occur in ductal epithelial cells.

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In order to investigate the risk and histopathology of lung cancer in dental professionals, we studied 4,138 males who were diagnosed as carrying malignant tumors at Osaka Medical Center for Cancer and Cardiovascular Diseases, 24 of whom were dental professionals (dentists and dental technicians), and 71 of whom were medical professionals (physicians and pharmacists). We concluded that dental professionals have a high risk of developing lung cancer, and the histopathology of their disease was highly likely to be adenocarcinoma.

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We did a survey of cleft lip and/or palate patients who visited various clinical specialties in Osaka Dental University Hospital from 1983 onward. There were 429 patients (212 males and 217 females) ranging in age from newborn to 50 years. Forty-six percent of the patients were first seen in the Orthodontics Department, 33% in the Oral Surgery Departments (1 and 2), and 14% in the Pediatric Dentistry Department. Fifty-nine percent of the patients had clefts of both the lip and palate, and males with this condition slightly outnumbered females. In contrast, females were 3.7 time as likely as males to have cleft palate alone. We found that 12-year-olds who had little or no dental consultation before age 12 had more carious teeth than those who had 5 or more years of professional dental guidance.

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Oral examination was conducted as a part of a general health examination for the staff at Osaka Dental University for the first time in June 1995. The examination for dental caries and periodontal disease (CPITN) was done by the staff of the Department of Preventive Dentistry, and oral health behavior was investigated by questionnaire. Four hundred and thirty-six (88.1%) of the staff members participated. The mean DMFT was 12.2, and mean DMFS was 37.4. Although 28.9% of the dental hygienists needed treatment for dental caries, this figure was about 50% for the doctors, dentists, technicians, nurses and office workers. Distribution of the CPITN codes for the staff was 8.7% for code 0, 10.1% for code 1, 51.6% for code 2, 24.3% for code 3 and 5.3% for code 4. This indicates that about 80% of the staff had dental calculus. We found that the dental hygienists had the best oral conditions and oral health behavior. These results may be useful in formulating programs and strategies for oral health administration of employees.

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