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Biomedical subjects

D Beighton

Publications and source records attributed to D Beighton.

At least 145 records · Page 8Linked to original sources
PubMed1983

Periodontal disease in five and six year old children.

The purpose of this study was to determine the prevalence and severity of gingivitis in a sample of primary school children. One hundred and twenty eight children with an average age of 6 years 0 months (SD +/- 4 months) were examined for oral hygiene status using the Plaque Index (Pl.I.) and the Calculus Index (C.I.). The periodontal status was assessed using the Gingival Index (G.I.) and recording gingival sulcus depths about selected teeth. The significance of factors associated with the G.I. was determined using multiple classification analysis. The incorporated factors were Pl.I., age and sex. The scores for Pl.I., and G.I., and Pl.I. and sulcus depth were significantly correlated. The majority of children had a maximum Pl.I. score of 2, a maximum C.I. score of 0, a maximum G.I. score of 1, and maximum sulcus depth of 2 mm. The regressands Pl.I. and age used in the multiple classification analysis explained only 28% of the variance in the G.I. data. Also, the analysis did not indicate the children's sex as a significant source of explanation for the variance of the G.I.

Australia↗
PubMed1982

The streptococcal flora of the tongue of the monkey Macaca fascicularis.

The major streptococcal biotypes in the 8 monkeys investigated resembled Streptococcus sanguis and Streptococcus mitior with Streptococcus salivarius forming only 5 to 6 per cent of the total colony count and being isolated from only 4 monkeys. The predominant tongue streptococci were not isolated from the dental plaque. Similarly, Streptococcus mutans, present in large numbers in the plaque of monkeys fed sucrose-rich diets, was isolated from the tongue of only 2 animals and formed only 2.4 per cent of the total colony count. Changing from a starch-based maintenance diet to sucrose-rich diets did not significantly alter the tongue flora except that the proportion of typical Strep. sanguis was significantly reduced. The oral streptococcal flora of monkeys is similar in distribution to that found in the human mouth.

Animals↗
PubMed1982

The distribution of the cariogenic bacterium Streptococcus mutans in the gastrointestinal tract of monkeys (Macaca fascicularis).

The success of oral vaccines based on Strep. mutans might be influenced by its presence in the gastrointestinal (GI) tract. Enumeration of Strep. mutans at various sites of the GI tract of sucrose-fed monkeys revealed a localized distribution. High numbers of Strep. mutans were recovered from only the dental plaque, caecum and the large intestine. Where Strep. mutans was not detectable in the dental plaque it could not be isolated from regions of the GI tract sampled. The absence of Strep. mutans from the small intestine suggests that the disparate results obtained from experiments in which this organism was used to immunize monkeys orally, are not attributable to the prior colonization of such an immunologically important region.

Animals↗
PubMed1982

The acquisition of Streptococcus mutans by infant monkeys (Macaca fascicularis) and its relationship to the initiation of dental caries.

The acquisition and transmission of Streptococcus mutans by 16 consecutively born infant monkeys (Macaca fascicularis) was studied. The 16 infant monkeys were weaned in four groups and caged together to form a commune. Transmission from mother to infant occurred infrequently. Streptococcus mutans was isolated from nine of the mothers but only from the dental plaque of two infant monkeys at weaning at which time the predominant streptococci were S. sanguis and S. mitior. One further animal was colonized by S. mutants during the formation of the commune, but only after it was caged with an infant harbouring the same organism. For 46 d after the completion of the commune, the monkeys were fed a starch-based diet during which time S. mutans of serotypes c, e or h were isolated from the faeces of all 16 animals and from the dental plaque taken from the developmental groove of the first deciduous molar of 11 animals. Faecal transmission appeared to be an important factor in the spread of S. mutans between monkeys in the commune. The monkeys were then fed a caries-promoting high sucrose diet resulting in a rapid increase in the proportion of S. mutans in the plaque and in the faeces. Streptococcus mutans serotype e was more frequently isolated from both plaque and faeces and its predominance may in part be due to the production of a bacteriocin active in vitro against S. mutans serotype h and other species of oral streptococci isolated from monkey dental plaque. The proportion of S. mutans in the developmental groove 8 d after the introduction of the high sucrose diet was significantly related to both the caries status of the groove and the total caries score 6 months later. The results suggest that, in this model of human dental caries, S. mutans is the major bacterial factor in the initiation of tooth decay.

Aging↗
PubMed1982

An effect of communal caging on the streptococcal flora of the dental plaque of monkeys (Macaca fascicularis).

22 monkeys were randomly allocated to one or other of 2 communes and fed a caries-promoting high sucrose diet. After 28 weeks commune 1 (13 monkeys) was found to harbour Streptococcus mutans serotype e as the predominant streptococcal species, but no monkey in commune 2 harboured this serotype. Instead the 9 monkeys of commune 2 harboured Streptococcus milleri in their dental plaque. The significance of these observations on the use of monkeys as a model of human dental caries is discussed.

Animals↗
PubMed1981

The isolation of characterization of Streptococcus mutans serotype h from dental plaque of monkeys (Macaca fascicularis).

A new serotype (h) of Streptococcus mutans was isolated from the dental plaque of monkeys (Macaca fascicularis). Serotype h strains fermented mannitol and melibiose but not sorbitol or raffinose, failed to hydrolyse aesculin and arginine, did not produce hydrogen peroxide and were unable to grow in the presence of bacitracin at 2 units ml-1. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of whole-cell proteins showed serotype h strains to be closely related to strains of genetic group III (i.e. serotypes d and g). The serotype-specific antigen of serotype h contained glucose and galactose but was antigenically distinct from the polysaccharide antigens of serotypes a, d and g. Serotype h strains preferentially colonized developmental grooves of teeth and the proportion of serotype h in the plaque flora was greater in monkeys fed a sucrose-rich diet than in monkeys fed a starch-based diet. A serotype h strain was cariogenic for germ-free rats fed a high-sucrose diet, and serotype h strains appear to be implicated in the caries process in monkeys.

Animals↗
PubMed1980

Manganese antagonizes the inhibitory effect of fluoride on the glucose metabolism of Streptococcus mutans.

Manganese stimulated the utilization of glucose by Streptococcus mutans, Streptococcus sanguis, Streptococcus mitior and Streptococcus milleri. S. mutans serotype c strains formed larger amounts of intracellular polysaccharide, lactic acid and produced a lower terminal pH in glucose broth when grown in the presence of 0.5 mM Mn. Manganese stimulated the utilization of glucose by resting cell suspensions of each of the four oral streptococcal species examined. Fluoride inhibited the utilization of glucose by the streptococci and Mn, but not calcium or magnesium, was found to counteract the inhibitory effect of fluoride.

Fluorides↗
PubMed1980

The effects of fluoride on the growth of oral streptococci.

Four species of oral streptococci were examined for their ability to grow in a complex medium supplemented with NaF, and at various pH levels. Streptococcus mutans strains were the most susceptible to inhibition, with Streptococcus mitior and Streptococcus sanguis being the least affected. The S. mutans genotype comprising serotypes c, e and f was more susceptible to inhibition by fluoride than was the genotype comprising serotypes d and g. The results suggest that the fluoride concentration of dental plaque might influence the relative proportions of the species of streptococci found in dental plaque.

Dental Plaque↗
PubMed1978

The effects of cadmium on the growth of some oral microorganisms and their ability to bind cadmium.

All seven oral Actinomycetaceae tested grew in broth containing 10 microgram/ml Cd. After 24 hours' growth A viscosus WVU 626 bound nearly 20 microgram Cd/mg dry wt. The amount of Cd bound varied during the growth cycle, being maximal (90 to 100 microgram/mg dry wt.) after 5 hours' growth. Addition of 50 microgram/ml chloramphenicol to actively growing cells inhibited further Cd binding. In contrast S mutans FA1 was greatly inhibited by 2.5 microgram/ml Cd and bound only 1.3 microgram Cd/mg after 24 hours' growth in broth containing 2.5 microgram/ml Cd.

Actinomyces↗
PubMed1977

A microbiological study of normal flora of macropod dental plaque.

The percentage bacterial composition of dental plaques from 12 macropods was determined. The major group of organisms was gram-positive filamentous and pleomorphic rods whose median representation was 92.2%. These were mainly Actinomyces viscosus (median value 62.5%) and Bacterionema matruchotii (median value 23.2%). Streptococci were poorly represented (median value 4.2%) as were anaerobic gram-negative organisms. Aerobic gram-negative bacteria were identified as neisseriae and Moraxella sp. The macropod plaque flora was compared with that of human beings and rodents and the differences discussed in relation to dietary differences and the early externalization of the marsupial young.

Actinomycetaceae↗
PubMed1977

The effects of fluoride on the percentage bacterial composition of dental plaque, on caries incidence, and on the in vitro growth of Streptococcus mutans, Actinomyces viscosus, and Actinobacillus sp.

Administration of 250 mug/ml NaF in drinking water to rats reduced both caries incidence (P less than 0.001) and the percentage of S mutans (0.01 greater than P greater than 0.001) although the percentage of Actinobacillus sp. was increased (P less than 0.001). An Actinobacillus sp. and S mutans FA1 both proliferated in NaF broth only if the NaF greater than 10 mug/ml, which was associated with the inhibition of acid production.

Actinobacillus↗