Relation of dietary preference to bite force and occlusal contact area in Japanese children.

The purpose of this study was to examine the relationship of dietary preference to bite force and occlusal contact area in Japanese elementary school children. A total of 348 children, aged 7-12 years, from two public elementary schools located in Okayama Prefecture, Japan, participated in the study. Clinical examination included decayed, missing and filled teeth (dmft and DMFT), and total numbers of deciduous and permanent teeth. Bite force and occlusal contact area were measured using a pressure-detecting sheet. Dietary preference was assessed using a questionnaire in which the answers were given in like/dislike form. Mann-Whitney U-test and multiple logistic regression analysis were applied to analyse the data. In multiple logistic regression analysis after adjustment for age, gender and total number of teeth present, children who liked cabbage and celery showed significantly higher bite force (P = 0.05 and P < 0.01, respectively) than those who disliked these. Children who liked cabbage and celery also showed higher occlusal contact area (P < 0.05 and P < 0.01, respectively) than those who disliked these. The Japanese elementary school children who liked hard foods such as cabbage and celery showed higher bite force and higher occlusal contact area than those who disliked these foods. A positive attitude towards harder food items might contribute to healthy development of the masticatory apparatus.

Inhibition of Bach1 ameliorates indomethacin-induced intestinal injury in mice.

BTB and CNC homolog 1 (Bach1) is a transcriptional repressor of heme oxygenase-1 (HO-1). It plays an important role in the feedback regulation of HO-1 expression, which protects cells from various insults including oxidative stress and inflammatory cytokines. However, the role of Bach1 in intestinal inflammation remains unclear. In this study, the role of Bach1 in intestinal mucosal injury was elucidated using 8-week-old female C57BL/6 (wild-type) and homozygous Bach1-deficient C57BL/6 mice. Intestinal mucosal injuries induced by a single subcutaneous administration of indomethacin were evaluated macroscopically, histologically, and biochemically. Mucosal protein content and chemokine mRNA levels were determined by real-time PCR. Our results showed that the indomethacin-induced intestinal injury was remarkably improved in Bach1-deficient mice. Histological examination showed that the area of injured lesion was decreased in Bach1-deficient mice compared to wild-type mice. Administration of indomethacin induced expression of inflammatory chemokines such as KC, MIP1alpha and MCP1, which was suppressed in Bach1-deficient mice. Myeloperoxidase activity in the intestinal mucosa was also significantly decreased in Bach1-deficient mice. Additionally, Bach1 deficiency enhanced immunopositivity of HO-1 in the intestinal mucosa after indomethacin administration. Disruption of the Bach1 gene thus caused inhibition of mucosal injury, indicating that inhibition of Bach1 may be a novel therapeutic strategy for treating indomethacin-induced intestinal injury.

Interleukin 12 production by monocytes from patients with psoriasis and its inhibition by ciclosporin A.

BACKGROUND: Psoriasis is a T-helper (Th)1 cytokine-mediated chronic skin disease and interleukin (IL)-12 has been shown to play a major role in the development of Th1 responses. OBJECTIVES: To elucidate the role of IL-12 in the pathogenesis of psoriasis and to study the effect of ciclosporin A (CsA) on Th1 deviation of this disease. PATIENTS/METHODS: We investigated IL-12 production by stimulated monocytes from patients with psoriasis who were treated with or without CsA. Monocytes were stimulated with interferon-gamma plus lipopolysaccharide (LPS) or Staphylococcus aureus Cowan strain I (SAC). The amount of IL-12 p70 produced by stimulated monocytes was evaluated by enzyme-linked immunosorbent assay. RESULTS: Compared with those from normal controls, LPS- but not SAC-stimulated monocytes from patients with psoriasis produced significantly higher amounts of IL-12. Interestingly, LPS-stimulated monocytes from patients with psoriasis treated with CsA produced significantly decreased amounts of IL-12 compared with those patients not treated with CsA. CONCLUSIONS: Our results suggest that IL-12 production by monocytes may have a critical role in the pathogenesis of psoriasis, and that the therapeutic effect of CsA on psoriasis may be achieved by correcting the deviation of the Th1/Th2 balance.

Computer graphics of center of masticatory forces in complete dentures.

1. INTRODUCTION. In dental education, it is valuable to show visually the differences between a good-fitting and an ill-fitting complete denture. A vector of masticatory forces across all the teeth of the denture is available to estimate the capability of the denture. The vector is simple while the forces exerted on a denture are very complex. A vector has only two factors, the point of application (center of force) and the magnitude. Because a complete denture acts as a unit, we can obtain the vector from electrical signals detected by transducers installed in the denture base. The aim of this study was to develop software which is able to show visually to dental students, the differences between the vectors of the dentures of three representative complete denture wearers. 2. METHODS. Three subjects, each with either a good, a moderate or an ill-fitting complete denture, were selected. Subject 1 could use the denture very comfortably during experiment. Subject 2 was uncomfortable at the insertion of the new denture, but after adaptations to the denture he could use it very well. Subject 3 had been uncomfortable during the experiment. A bottom complete denture was divided into upper and lower parts. These were connected by the four force-detecting units which were embedded in approximately the first premolar and second molar regions on both sides of the denture. The electric signals from these units during the chewing of peanuts and raisins (sampling time period: 30 msec) were recorded as digital signals and processed using the computer (Macintosh IIcx, Apple Computer) with the A/D converter (Lab-NB), National Instruments). Center and magnitudes of masticatory force were calculated from all sampling points using our newly developed software scripted by ¿C¿ (MPW C, Apple Computer). On the other hand, a tracing of the external shape of the dentition of the denture was made using the project (V-12, NIKON). The tracing of the dentition, with center and magnitude of masticatory forces was displayed successively on the screen like a movie. 3. RESULTS AND DISCUSSION. The typical scenes in each cases during one stroke of chewing were illustrated in Figure 1. The center of each circle is the point of application of the vector and the diameter of the circle is its magnitude. As time proceeded, the diameter of the circle became larger. As the period of denture insertion proceeded, the center of masticatory force was localized on the first molar region in subject 1, was shifted from the middle of the dental arch to the molar in subject 2, and was irregularly moved on the middle of the dental arch in subject 3. This software could visualize the center of masticatory force as an indicator of the type of fitting of the complete denture on display.

Inhibition of adhesion-promoting activity of a human salivary protein which promotes adhesion of Streptococcus mutans JBP to hydroxyapatite.

The adhesion-promoting proteins (APP) (molecular mass approx. 300 kDa), which promote adhesion of Streptococcus mutans JBP (serotype c) to hydroxyapatite, were isolated from human submandibular-sublingual (SMSL) saliva by gel filtration on a Trisacryl GP2000 M column. The effects of hexoses, pentoses, methyl-pentoses, hexosamines, N-acetylhexosamines, a basic amino acid, polyamines and ammonium chloride on the bacterial adhesion-promoting activity of the APP were examined. Galactosamine, mannosamine, L-lysine, spermine, putrescine, and ammonium chloride inhibited the adhesion-promoting activities of the APP. The other sugars, including the N-acetylhexosamines, were without effect. Thus, compounds containing a primary amino-group appear to have a specific inhibitory effect on adhesion of S. mutans JBP to APP adsorbed onto hydroxyapatite, an activity which is lost if the amino-group is acetylated.

Detection of porcine rotavirus in stools by a latex agglutination test.

We developed a simple agglutination test for the detection of porcine rotavirus in stools from pigs with diarrhea. The virus was detected with high sensitivity and specificity by a slide agglutination test using latex particles coated with antibody against the porcine rotavirus strain OSU (LA-antiOSU). The agglutination of LA-antiOSU with OSU on a glass slide was evident macroscopically within 2 min. The sensitivity of this latex agglutination (LA) test was four times higher than that of the electron microscope method. The LA test is available for the rapid diagnosis of porcine rotavirus infections.

Polymorphism of submandibular-sublingual salivary proteins which promote adhesion of Streptococcus mutans serotype-c strains to hydroxyapatite.

Previously, we showed that human submandibular-sublingual (SMSL) salivas contain one or more proteins, Mr circa 300,000 daltons, which specifically promote adhesion of Streptococcus mutans serotype-c strains to hydroxyapatite. Also, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that the adhesion-promoting proteins (APPs) exhibit heterogeneity. The aims of the present study were to determine whether APPs are generally present in human SMSL salivary secretions and to characterize the noted heterogeneity. Acid-stimulated SMSL saliva samples were obtained from 54 Japanese subjects, and Mr values were obtained by SDS-PAGE. APPs were present in all saliva samples examined, though at significantly different concentrations. The APPs occurred as either single (20 subjects) or double bands (34 subjects), with a mean Mr (88 bands) of 297 kD and a range of 248-338 kD. A plot of the frequency distribution of the APPs according to Mr showed a trimodal distribution, with mean Mr values, standard deviations, and ranges for the three groups being 265 (S.D., 6.9; range, 248-278), 293 (S.D., 6.7; range, 280-305), and 320 (S.D., 7.0; range, 310-338) kD. Variations of Mr within groups may be attributed to experimental variation, although microheterogeneity cannot be excluded. Differences between groups can best be explained in terms of three polymorphic proteins, with low (L), intermediate (I), and high (H) Mr values. Six phenotypes were detected with L, I, H, LI, LH, and IH Mr bands. A Hardy-Weinberg analysis showed that the phenotype data fit a single-gene, three-alleles model.(ABSTRACT TRUNCATED AT 250 WORDS)

A human salivary protein which promotes adhesion of Streptococcus mutans serotype c strains to hydroxyapatite.

The aim of this study was to investigate the nature of one of the factors in human submandibular-sublingual (SMSL) saliva which promotes the adhesion of Streptococcus mutans serotype c strains to hydroxyapatite (HA) surfaces. Gel filtration chromatography of SMSL saliva on Trisacryl GF2000 gave a void volume peak which contained the major fraction of adhesion-promoting activity for S. mutans JBP to HA. Maximum adhesion-promoting activity, however, eluted slightly later than the maximum 220-nm absorbance of the void volume peak. Gel filtration of the void volume material after treatment with sodium dodecyl sulfate (SDS) gave an early-eluting larger peak followed by a smaller peak with which the adhesion-promoting activity was associated. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) showed the presence of relatively slowly migrating material associated with the larger inactive peak, presumably mucin, and a faster-migrating band(s) associated with the smaller active peak. SDS-PAGE indicated molecular weights in the range of 300,000 to 350,000 by extrapolation from size standards. Comparison of SMSL from five individuals showed the presence of single bands or double bands associated with adhesion-promoting activity, indicating genetic polymorphism. The active material did not resemble either secretory immunoglobulin A, based on SDS-PAGE and immunoassay, or fibronectin, based on SDS-PAGE, and also differed in molecular weight from salivary mucins and salivary constituents previously reported to promote aggregation of certain oral bacteria, but a relationship to these materials cannot be excluded. This adhesion-promoting material may play a significant role in the initial colonization of tooth surfaces by S. mutans strains.

Cariogenic virulence of Streptococcus mutans AHT mutants with altered in vitro adherence abilities in hamsters.

Plaque-forming ability and cariogenic virulence of Streptococcus mutans AHT mutants having varying in vitro adherence abilities were studied in hamsters reared on a high sucrose diet over a period of 64 days. The parent wild-type strain produced heavy plaque and extensive carious lesions on molars. However, mutants M1, M2, and M13, which have lost the ability to form adhesive deposits on glass when grown in sucrose broth, and mutant M9, which adheres firmly to glass but in an extremely small amount, could not be recovered from the mouths of animals even after repeated inoculations at weekly intervals throughout the experimental period. Mutant M35, which produces a large amount of loosely adhering deposits in vitro, became established and persisted on molars, but its recovery was extremely low. None of the mutants, including M35, significantly produced plaque and caries in hamsters. Possible causes of this inability to form plaque and the avirulence of mutants are discussed.