Suppression of Streptococcus mutans Biofilm Formation and Gene Expression by PRG Barrier Coat: A Molecular and Microscopic Study for Preventing Dental Caries.

PURPOSE: This study aimed to investigate the inhibitory effect of a PRG Barrier Coat on biofilm formation and structure by Streptococcus mutans and propose an effective method for preventing dental caries. MATERIALS AND METHODS: Streptococcus mutans MT8148 biofilms were obtained from hydroxyapatite disks with and with- out a PRG Barrier Coat. Scanning electron microscopy (SEM) was used to observe the 12- and 24-h-cultured biofilms, while reverse-transcription polymerase chain reaction (qRT-PCR) was used to quantify caries-related genes. Biofilm adhe- sion assessments were performed on glass. Statistical analysis was performed using a two-sample t-test. RESULTS: A statistically significant difference in Streptococcus mutans biofilm adhesion rate was observed between the con- trol and PRG Barrier Coat-coated samples (p < 0.01). However, there was no statistically significant difference in total bacter- ial count or biofilm volume (p > 0.05). SEM revealed that the PRG Barrier Coat inhibited biofilm formation by Streptococcus mutans. Real-time RT-PCR revealed that the material restricted the expression of genes associated with caries-related bio- film formation. However, the suppression of gtfD and dexB differed from that of other genes. CONCLUSION: PRG Barrier Coat suppressed biofilm formation by Streptococcus mutans by inhibiting the expression of in- soluble glucan synthase, which is associated with primary biofilm formation. The material also affected gene expression and altered the biofilm structure. Tooth surface-coating materials, such as PRG Barrier Coat, may improve caries preven- tion in dental practice.

Acute oral complications in a pediatric patient with acute lymphoid leukemia.

Pseudomonas aeruginosa is a low-virulence pathogen that can cause infection in immunocompromised patients. Among pediatric hematologists, it is known that careful attention should be paid to P. aeruginosa as the bacteria responsible for intraoral inflammation, and antibiotic therapy targeting P. aeruginosa is the first-line treatment during neutropenia in patients with hematological malignancy. Immunosuppressed patients, however, are at high risk of developing inflammation. Here, we report a case involving a 10-year-old patient with acute lymphoid leukemia (ALL), in which P. aeruginosa synergistically acted with pre-existing gingivitis to induce unusual oral necrotic lesions, leading to acute buccal cellulitis and pus discharge from external sinus tracts.

Treatment when prognostic factors do not match St. Gallen recommendations: profiling of prognostic factors among HR(+) and HER2(-) breast cancer patients.

BACKGROUND: The St. Gallen consensus provides treatment recommendations for breast cancer based on prognostic factors. Although many patients' prognostic patterns are not easily matched with the prognostic patterns listed in the St. Gallen consensus, there has been no systematic investigation reporting the gap between treatment recommendations and actual postoperative treatment choices in clinical practice. METHODS: Four hundred seventy-one patients with hormone receptor-positive [HR(+)] and human epidermal growth factor receptor type 2-negative [HER2(-)] breast cancer were analyzed. These patients were classified into either the "crisp treatment group" or "fuzzy treatment group" based on the definitiveness of postoperative treatment selection based on St. Gallen treatment recommendations. The patients in the fuzzy treatment group were further classified into strata in which patients within each stratum shared the same prognostic factor patterns with similar recurrence rates. RESULTS: A total of 87.3% of HR(+)HER2(-) patients were designated to the fuzzy treatment group. Four prognostic strata were constructed according to the survival tree model, and revealed that patients with poor prognostic profiles tended to receive endocrine therapy with chemotherapy. This suggests that postoperative chemotherapy is useful, although there was no statistical significance. CONCLUSIONS: We constructed prognostic profiles of patients in the fuzzy treatment group and examined the recurrence rates associated with two treatment regimens within each prognostic profile. These findings are exploratory, but they may be useful for planning prospective studies of the effectiveness of postoperative treatment regimens among patients with a heterogeneous combination of prognostic factors.

Long-term natural history of acquired cystic disease of the kidney.

Patients with acquired cystic disease of the kidney (ACDK) were followed longitudinally over an average of 21.7 +/- 5.4 years to determine the natural history of the disease; that is, how big the kidneys become, when the kidney size reaches a plateau, and when the size regresses. Twenty-seven male and 20 female patients with chronic glomerulonephritis treated at our hospital were investigated. CT scans were performed once a year and kidney volume was measured. Two different quadratic curves with a node of 5.2 years for males and 2.5 years for females after the start of hemodialysis were fitted to log-transformed kidney volume to the duration of hemodialysis using a linear mixed model. The maximum kidney volume in male patients was obtained 21.1 years after the start of hemodialysis using this model. Peak values of kidney volume were demonstrated in 19 of 26 cases during the observation period. The median peak value (interquartile range) of bilateral kidney volumes was 274 (165-849) mL/1.73 m(2) occurring 19.1 +/- 4.5 years after the start of dialysis. In one male patient who had undergone nephrectomy due to renal cell carcinoma and in two of the remaining 26 male patients, the maximum kidney volume of 782 (residual kidney), 1151, and 1129 mL regressed to 428, 616, and 847 mL (reduction rate: 45.3, 46.5, and 25.0%) at 20.6, 25.4, and 23.1 years after the start of hemodialysis, respectively. Kidney enlargement due to ACDK reached a plateau after 21.1 years of hemodialysis in the male patients. Partial regression of severe ACDK may occur naturally after long-term hemodialysis without renal transplantation.

The P561T polymorphism of the growth hormone receptor gene has an inhibitory effect on mandibular growth in young children.

P561T heterozygous missense mutation in the growth hormone receptor (GHR) is a candidate genetic polymorphism (single-nucleotide polymorphism) for human mandibular growth. The purpose of this study was to assess whether this mutation affects mandibular growth during early childhood. The difference in mandibular growth between P561T heterozygous and wild-type individuals was analysed by cephalometric measurements during childhood. The subjects included 33 children with mandibular protrusion (aged 3-12 years, 16 males and 17 females) and 27 normal children (aged 3-13 years, 14 males and 13 females). Genomic DNA extracted from buccal epithelial cells was genotyped for the P561T heterozygous mutation with a molecular analysis (polymerase chain reaction--restriction fragment length polymorphism method). Two of the patients with normal occlusion and five with mandibular protrusion were heterozygous for the mutation. Chi-square analysis showed that the frequency of this mutation did not differ statistically between the normal and mandibular protrusion subjects. Multilevel model analysis of the 101 cephalograms showed that the mutation reduced the linear measurements of the mandible. These findings suggest that P561T heterozygous mutation affects mandibular growth during early childhood, and this mutation in the GHR gene is hypothesized to function as an inhibitory factor in the process of mandibular growth.

Sequential aldol condensation catalyzed by hyperthermophilic 2-deoxy-d-ribose-5-phosphate aldolase.

Genes encoding 2-deoxy-d-ribose-5-phosphate aldolase (DERA) homologues from two hyperthermophiles, the archaeon Pyrobaculum aerophilum and the bacterium Thermotoga maritima, were expressed individually in Escherichia coli, after which the structures and activities of the enzymes produced were characterized and compared with those of E. coli DERA. To our surprise, the two hyperthermophilic DERAs showed much greater catalysis of sequential aldol condensation using three acetaldehydes as substrates than the E. coli enzyme, even at a low temperature (25 degrees C), although both enzymes showed much less 2-deoxy-d-ribose-5-phosphate synthetic activity. Both the enzymes were highly resistant to high concentrations of acetaldehyde and retained about 50% of their initial activities after a 20-h exposure to 300 mM acetaldehyde at 25 degrees C, whereas the E. coli DERA was almost completely inactivated after a 2-h exposure under the same conditions. The structure of the P. aerophilum DERA was determined by X-ray crystallography to a resolution of 2.0 A. The main chain coordinate of the P. aerophilum enzyme monomer was quite similar to those of the T. maritima and E. coli enzymes, whose crystal structures have already been solved. However, the quaternary structure of the hyperthermophilic enzymes was totally different from that of the E. coli DERA. The areas of the subunit-subunit interface in the dimer of the hyperthermophilic enzymes are much larger than that of the E. coli enzyme. This promotes the formation of the unique dimeric structure and strengthens the hydrophobic intersubunit interactions. These structural features are considered responsible for the extremely high stability of the hyperthermophilic DERAs.

Local community intervention through depression screening and group activity for elderly suicide prevention.

This study aims to evaluate outcomes of a community-based program to prevent suicide among the elderly (>or=65 years old) using a quasi-experimental design with two neighboring references. During 1999-2004, the program including depression screening and group activity was conducted by the public health nurses in the Minami district (population 1685) of Nagawa town, rural Japan. Pre-post changes in the risk of completing suicide were estimated by the incidence rate ratios (IRR). The risk for Minami's elderly females was reduced by 74% (age-adjusted IRR, 0.26; 90% CI, 0.07-0.98) more than the historical trend, while there was no change in the risk of Minami's males and nor in the male or female references. The local intervention using public health nursing would be effective against suicide for elderly females without diffusing to the surroundings.

Incisal paths during habitual mouth opening and closing movements of children with anterior reverse bite in the early mixed dentition.

The purpose of this study was to investigate whether the pathways of habitual mouth opening and closing in children with anterior reverse bite in the early mixed dentition differed from those of children with normal occlusion. The two subject groups for this study were composed of ten children with anterior reverse bite (reverse bite group) and twelve children with normal occlusion (normal occlusion group), respectively. These movements were measured by an optoelectronic analyzing system with six degrees of freedom. Movements of the incisal point were projected on the sagittal plane to characterize the paths, and sagittal angles between the incisal path and the horizontal plane were calculated and compared. Opening and closing sagittal angles in the reverse bite group were almost equal over the entire pathway, indicating that the pathways of habitual mouth opening and closing were similar. In contrast, all opening and closing sagittal angles in the normal occlusion group were different, especially close to maximum intercuspation, indicating that their pathway of habitual mouth opening differed from their mouth closing pathway. In conclusion, children with anterior reverse bite in the early mixed dentition have different patterns of habitual mouth opening and closing movements than children with normal occlusion.