Genetic characterization and conservation priorities of chicken lines.

Molecular markers are a useful tool for evaluating genetic diversity of chicken genetic resources. Seven chicken lines derived from the Plymouth Rock breed were genotyped using 40 microsatellite markers to quantify genetic differentiation and assess conservation priorities for the lines. Genetic differentiation between pairs of the lines (pairwise FST) ranged from 0.201 to 0.422. A neighbor-joining tree of individuals, based on the proportion of shared alleles, formed clearly defined clusters corresponding to the origins of the lines. In Bayesian model-based clustering, most individuals were clearly assigned to single clusters according to line origin and showed no admixture. These results indicated that a substantial degree of genetic differentiation exists among the lines. To decide priorities for conservation, the contribution of each line to the genetic diversity was estimated. The result indicated that a loss of 4 of the 7 lines would lead to a loss from 1.14 to 3.44% of total genetic diversity. The most preferred line for conservation purposes was identified based on multilocus microsatellite analysis. Our results confirmed that characterization by means of molecular markers is helpful for establishing a plan for conservation of chicken genetic resources.

Assessing genetic diversity and population structure for commercial chicken lines based on forty microsatellite analyses.

The aims of the current study were to assess genetic diversity, conduct genetic characterization, and evaluate usefulness of an individual assignment test for 12 commercial chicken lines using 40 microsatellite markers. A total of 268 distinct alleles were observed across the 12 lines, and 42 of the 268 alleles (15.7%) were unique to only 1 line. Mean observed heterozygosity within a line ranged from 0.295 to 0.664, and the highest value was obtained from 1 of the White Plymouth Rock lines. Significant deviations from the Hardy-Weinberg equilibrium were observed at several locus-line combinations, showing excess of heterozygotes in many cases. As a whole, genetic differences among the lines estimated by the fixation index were high at 29.8%, whereas higher genetic similarity was observed among White Leghorn lines despite their different breeding histories. Assignment test could correctly allocate individuals at the line level to their origins, with a high accuracy (96.6%). Individual-based genetic characterization would be a usable step to conserve chicken genetic resources. Here, guidelines for future breeding and management of these lines by the poultry industry are provided.

PCR detection of 5 putative periodontal pathogens in dental plaque samples from children 2 to 12 years of age.

BACKGROUND, AIMS: The purpose of this study was to detect the presence of Prevotella intermedia, P. nigrescens, Bacteroides forsythus, Treponema denticola, and Campylobacter rectus in plaque samples from 119 children, collected from their toothbrushes using a polymerase chain reaction (PCR). METHOD: The subjects were 24, 83, and 12 children with healthy gingiva, gingivitis, and periodontitis, respectively, ranging in age from 2-12 years old. Plaque samples were collected from all erupted teeth sites using a sterile toothbrush. The mean concentration of DNA recovered from the plaque samples was approximately 640 microg/ml, which was deemed sufficient for performing a PCR-based survey. RESULTS: The prevalence by PCR in healthy, gingivitis, and periodontitis subjects was 0.0%, 6.0% and 25.0% for P. intermedia, 45.8%, 79.5% and 50.0% for P. nigrescens, 33.3%, 63.9% and 58.3% for B. forsythus, 0.0%, 18.1% and 16.7% for T. denticola, and 100% in duplicate for C. rectus, respectively. CONCLUSION: Our survey indicated that P. intermedia and T. denticola were more associated with periodontal diseases, B. forsythus and P. nigrescens had a moderate prevalence in all clinical groups, while C. rectus were the most commonly detected species in the oral cavities of children suggesting establishment in their early years.

Relationship between gingival health and dental caries in children aged 7-12 years.

The purpose of this study was to investigate the relationship between gingival health and dental caries in elementary school children in Japan. The subjects were 474 children aged 7 to 12 years who attended dental check-ups at an elementary school. The Oral Rating Index for Children, which consists of five categories (+2, +1, 0, -1, -2), was used to rate the findings of the gingival health examination. The dental examination was performed using the WHO caries diagnostic criteria for DMFT. Children were divided into three groups: a healthier group (H-group) made up of those scoring +2 (excellent) or +1 (good), an equivocal group (E-group) made up of those scoring 0, and a gingival less-healthy group (L-group) made up of those scoring -2 (very poor) or -1 (poor). Overall percentages for the H-group, E-group and L-group were 48.3%, 21.5% and 30.2%, respectively. The number in the L-group increased with increasing age. The mean scores of the DT and DMFT in the H-group were significantly lower than those in the L-group (p < 0.01 and p < 0.05, respectively). The results suggest that oral hygiene instruction should be given to children in order to motivate self-care, not only to avoid dental caries but also to prevent gingivitis.

Detection of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in dental plaque samples from children 2 to 12 years of age.

The purpose of this study was to detect the presence of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in plaque samples from 104 children, collected from their toothbrushes using a polymerase chain reaction (PCR). The age range of all subjects was 2-12 years. 21, 73 and 10 children with healthy gingiva, gingivitis and periodontitis respectively were selected. Plaque samples were collected from all erupted teeth sites using a sterile toothbrush. The mean concentration of DNA recovered from brushing plaque samples was approximately 660 microg/ml, which was sufficient for performing a PCR-based survey. Both A. actinomycetemcomitans and P. gingivalis were detected in the primary and mixed dentition. The prevalence of A. actinomycetemcomitans in healthy subjects was 4.8%, and those with gingivitis and periodontitis was 6.8% and 20.0% respectively, while the prevalence of P. gingivalis was 4.8% in healthy subjects, and 9.6% and 20.0% in those with gingivitis and periodontitis, respectively. Our survey, using a toothbrush, indicated that A. actinomycetemcomitans and P. gingivalis are rarely present in oral cavities of healthy children.

In vitro study of antibacterial and antiadhesive activities of fluoride-containing light-cured fissure sealants and a glass ionomer liner/base against oral bacteria.

The aim of this study was to estimate the antibacterial and anti-adhesive properties of light-cured pit-and-fissure sealants containing fluoride (Teethmate F-1, TF; UltraSea-1 XT, US) or not containing fluoride (Teethmate A, TA)- and glass ionomer liner/base containing fluoride (Vitrebond, VB) against oral bacteria in vivo. VB inhibited the growth of S. mutans, S. oralis and L. casei aerobically and anaerobically, and TA and US inhibited the growth of only S. mutans aerobically. The numbers of adherent cells mediated by insoluble glucan for all materials were lower than that for the control tooth. The numbers of adhesional cells not mediated by insoluble glucan were larger than that for the control tooth. VB showed the highest concentration of fluoride released throughout the four-week observation period, and had the highest pH value. In this study, VB showed superior antibacterial action and fluoride-release compared with the other three materials.

Effect of oleanolic acid-cyclodextrin inclusion compounds on dental caries by in vitro experiment and rat-caries model.

Earlier work in vitro showed that oleanolic acid (OA) was a potential inhibitor of insoluble glucan (ISG) synthesis from mutans streptococci (MS). In this study, two oleanolic acid-cyclodextrin inclusion compounds (OA-CDs), oleanolic acid-G1-beta-cyclodextrin (OA-G1-beta CD) and oleanolic acid-beta-cyclodextrin (OA-beta CD), were assayed for their effects on ISG synthesis from Streptococcus mutans MT8148R, and on the growth of oral bacteria. OA-beta CD inhibited ISG synthesis by 55.3 and 37.4% at 62.5 and 15.6 micrograms/ml of OA, respectively. Both OA-CDs inhibited the growth of MS, S. sanguis, and S. salivarius at 4 to 8 micrograms/ml of OA. The anticariogenic effect of the OA-beta CD was examined in a rat-caries model. Rats in the infected control groups showed the highest caries score. The infected treatment group B (0.5% OA in diet) showed lower scores than the control group. These results suggest that OA-beta CD is a potential anti-caries agent.

A study of psychological stress created in dentists by children during pediatric dental treatment.

Stresses on dental practitioners arising from pediatric examination and treatment can be broadly divided into those produced by the child and those produced by the child's guardian (usually the mother). The present study examined the psychological influence of the child. A series of questions regarding psychological stress caused by child patients was administered to a group of dentists and, by factor analysis, reduced to a 21-item scale. The effectiveness of this instrument was examined for reliability and validity. The following results were obtained: 1. The 21 items in the scale were selected for their association with three primary factors: stress from mild resistance behavior, stress from moderate resistance behavior, and stress from determined resistance behavior. 2. The scale demonstrated high internal consistency and, by test-retest, high stability over time. 3. High scores on a standardized scale for psychological stress in everyday life were found to correlate positively to scores on the scale created in the present study. The correlation was significant beyond the 5 percent level. Confirmatory factor analysis found factor loading for all items of 0.50 or greater, with no duplication of factors within items. Both tests confirmed the validity of the scale. The above results indicate that the scale created in the present study is an effective instrument for measuring psychological stress in dental practitioners created by children during pediatric dental treatment and examination.

Intrafamilial distribution of mutans streptococci in Japanese families and possibility of father-to-child transmission.

The purpose of this study was to investigate the intrafamilial distribution of mutans streptococci in Japanese families using chromosomal DNA fingerprinting with three endonucleases; EcoRI, HindIII and HaeIII. The analysis of 1,908 isolates cultured from the dental plaque of 76 subjects from 20 families (20 married couples and 36 of their children) resulted in the identification of 144 genotypes containing 114 strains of Streptococcus mutans (serotype c, 66.7%; e, 12.5%) and 30 strains of S. sobrinus (d, 13.2%; g, 7.6%). A mean of 1.89 genotypes (from one to four) was harbored in individual subjects, and a mean of 4.10 genotypes from two to seven was harbored in individual families. Among the 70 genotypes found in the children, 36 (51.4%) were in agreement with their mothers and 22 (31.4%) were in agreement with their fathers. The other genotypes (18.6%) did not correspond with the parents. Homologous strains between parents were found in only two couples. This result showed that fathers or others as well as mothers can be sources of transmission. Further, the serotype d, e and g strains showed significantly higher probabilities of transmission than serotype c.

New tongue protector to prevent decubital lingual ulcers caused by tongue thrust with myoclonus.

We treated tongue ulcers in a twenty-two-month-old male child with Gaucher disease and several neuronopathic symptoms, including frequent convulsions. Because the patient was always thrusting his tongue and biting with his upper and lower primary incisors during the myoclonus and convulsions, traumatic decubital ulcers on the dorsum and ventral surface of the tongue were formed. During the convulsions, bleeding and pus discharges were observed. For the protection of the tongue from the teeth, a tongue protector was fabricated from a soft silicone relining material used for dentures. The protector covered the mandibular primary central incisors, the alveolar ridge, and the ventral surface, apex and dorsum of the tongue. The ulcer symptoms completely disappeared after two months of using the protector.

Effects of various types of Triton X on the susceptibilities of methicillin-resistant staphylococci to oxacillin.

We examined the effect of six types of the nonionic detergent Triton X on the susceptibilities of methicillin-resistant staphylococci to oxacillin. We used five methicillin-resistant Staphylococcus aureus isolates and 17 methicillin-resistant coagulase-negative staphylococci isolates. All strains of S. aureus, S. epidermidis and S. sciuri had enhanced susceptibility to oxacillin following exposure to the types of Triton X having 7-13 polymerized ethylene oxides. These strains were altered from homogeneously resistant to heterogeneously resistant by Triton X-100. Those types of Triton X that affected the resistance level also promoted the release of lipoteichoic acid. These results and those of previous studies suggest that Triton X might act on factors other than the mecA or femA products.

In vitro susceptibility of Staphylococcus aureus including MRSA to four disinfectants.

The spread of nosocomial infections caused by pathogenic organisms such as methicillin-resistant S. aureus (MRSA) has prompted the dental community to focus more attention on certain control strategies. In the present study, we tested the abilities of the four skin disinfectants (povidone iodine, benzalkonium chloride, chlorhexidine gluconate, and ethanol) to prevent horizontal transmission of MRSA in the dental office. The bactericidal activities of the disinfectants were evaluated by the decrement over time of viable cell numbers of four clinical isolated strains of S. aureus: two MRSA strains and two methicillin-sensitive S. aureus (MSSA) strains. The most effective disinfectant was 70 percent ethanol, which eradicated both MRSA and MSSA in less than three minutes. The 0.1 percent chlorhexidine gluconate proved the least effective of four disinfectants. More than 10(2) bacteria survived despite exposure to it for thirty minutes.

A long-term survey of methicillin-resistant Staphylococcus aureus in the oral cavity of children.

Methicillin-resistant Staphylococcus aureus (MRSA), an indigenous bacteria in healthy people, often causes nosocomial infections. If the host human becomes compromised, MRSA can cause a serious infection. The long-term colonization of MRSA increases this risk. The purpose of this study was to demonstrate the incidence of S. aureus and MRSA colonization in the oral cavities of healthy children, and to examine the stability of identical strains of MRSA over a long-term period. Fourteen children were examined in two stages (first stage: 1987-88, second stage: 1992-93). Five of the 14 children were negative for S. aureus in both stages, seven children were positive in both stages and two children were positive in only the second stage. The children who were colonized with S. aureus in the first stage always harbored the bacteria in the second stage. Of the seven children that were positive for S. aureus in both stages, three persisted in carrying MRSA. We compared two MRSA strains isolated from the same children in both stages by coagulase typing, antibiogram typing and DNA fingerprinting. In two children, the strains showed the same coagulase types, similar antibiograms and similar DNA fragment profiles. These data strongly suggest that identical strains of MRSA persisted in the oral cavities for more than five years, and that the oral cavity can serve as a reservoir for MRSA with the potential to cause nosocomial infections.

Effects of training in management of child behavior for dental hygiene students.

The reliability and validity of a Confidence of Dental Hygienist in Child Management Scale were examined. Forty-eight dental hygiene students, nine dental staff, and thirty-one dentists were subjects for the reliability and validity scale. The acceptable level of the reliability on the Scale was shown by internal consistency and stability. The confidence scores of the clinician's group were significantly higher than the confidence scores of the students. The reliability and validity of the Confidence Scale were established. Next, we evaluated the effect of behavioral science training, using videotape feedback and role playing on twelve dental hygiene students. Six students received the training, the other six students, the controls, had no training. The confidence scores of the training group were significantly higher than those of the control group, demonstrating that the training was effective for dental hygiene students.

Changes in urinary excretion of catecholamines and their metabolites in pediatric dental patients.

To explain the changes in urinary excretion of catecholamines and their metabolites in pediatric dental patients, comparative measurements of three catecholamines (dopamine, noradrenaline and adrenaline), and five metabolites (3, 4-dihydroxyphenylacetic acid, normetanephrine, metanephrine, homovanillic acid, and vanillylmandelic acid) were made before and after dental treatment. The investigations were carried out in seven healthy young children between three and five years of age. All these children had previously displayed negative behavior in dental treatment. There were statistically significant increases (P < 0.05) in urinary noradrenaline, adrenaline, and normetanephrine levels during dental treatment. These results suggest that these three substances could be a useful tool for determining the occurrence of dental stress in children.

Adrenal catecholamine secretory responses in young and adult dogs.

To elucidate the secretory sensitivity of the adrenal medulla in young animals, a comparative study of the adrenal secretory reactivity in young and adult dogs was made. In the isolated perfused adrenal gland, acetylcholine, nicotine, muscarine (10(-6)-10(-4) M) and high K+ (15-45 mM) enhanced catecholamine release. The release of catecholamines, expressed per weight of adrenal gland and caused by cholinergic secretagogues, was significantly higher in young dogs than in adult dogs. The proportion of noradrenaline to adrenaline plus noradrenaline in the tissue was higher in young dogs. The proportion of noradrenaline in the effluent was higher by increasing the concentrations of the stimulants, up to a similar level of the tissue noradrenaline/noradrenaline+adrenaline ratio. In in vivo studies, the increase in catecholamine concentration, especially of noradrenaline, in the plasma of femoral arteries, induced by intravenous injection of nicotine, was higher in young dogs than in adult dogs. We also measured the catecholamine-synthesizing enzymes activities in the adrenal medulla. Tyrosine hydroxylase and phenylethanolamine-N-methyltransferase activities were lower in young dogs, but there was no difference in dopamine-beta-hydroxylase activity between young and adult dogs. These results may suggest that young dogs are more sensitive to cholinergic stimulation in spite of their low catecholamine-synthesizing enzyme activity.

Incidence and characterization of Staphylococcus aureus from the tongues of children.

Three hundred and seven children who had no diseases other than dental disease were examined for their oral carriage of Staphylococcus aureus, the most common persistent human pathogen. Eighty-four percent of them were positive for staphylococci, and 33% were positive for S. aureus. Among the 100 strains of S. aureus isolated, 40 strains produced enterotoxin, and 19 strains produced exfoliative toxin. Their susceptibility to antibiotics was also investigated: Six strains demonstrated resistance to methicillin (MIC greater than or equal to 12.5 microgram/mL), and 50% of the isolates were borderline resistant (MIC of 3.13 to 6.25 micrograms/mL) to the drug. These data suggest that the mouths of children could be reservoirs of pathogenic S. aureus.

[Studies concerning the effect of sport drinks on hydroxyapatite dissolution].

The purpose of this study was to evaluate the erosive properties of sport drinks and to clarify the facts which effect these properties. We analysed the contents of 3 kinds of sport drinks and measured their capacity to dissolve hydroxyapatite in vitro under several duration times. The following results were obtained: 1) The pH Values of the sport drinks ranged from 2.91 to 4.07. 2) The total sugar concentration of the sport drinks ranged from 3.24 to 5.95%. The sugar were consisted mainly to sucrose, glucose and fructose, but their proportion in the sport drinks had different values respectively. 3) After stirring for 1 and 5 minutes, there was a negative correlation (Spearmann's rank correlation coefficient test) between the pH values of the sport drinks and the amounts of Ca2+ released into them. And after stirring for 10 and 20 minutes, there was a negative correlation between the Ca concentrations of the sport drinks and the amounts of Ca2+ released into them. 4) The addition of sugar to the sport drinks showed no effect on their capacity to dissolve hydroxyapatite. The results suggested that tooth erosion depends on the pH value of the sport drink at the early stage when the tooth contacted it, and also tooth erosion depends on the Ca concentration of the sport drink when the tooth is in contact with it for a long time.

In vitro susceptibility of Campylobacter jejuni to rokitamycin.

The susceptibilities of 100 clinical isolates of Campylobacter jejuni to rokitamycin, a new macrolide, and eight other oral antibiotics were tested by using a broth microdilution method. Rokitamycin demonstrated antibacterial activity that was higher than those of fosfomycin and the tetracyclines and comparable to those of erythromycin and clindamycin, whereas it was slightly less active than the quinolones.