Effectiveness of an oral health education seminar for paediatric and family medicine residents.

AIM: To assess the immediate effect of a 60-minute oral health educational seminar for paediatric and family medicine residents in improving their knowledge, attitude, likelihoodtowards incorporating oral health preventive practice in their current practices to well-child visits, and confidence in identifying and referring patients with dental trauma. MATERIALS AND METHODS: Baseline pre- and post-test design was used to evaluate the immediate effect of a 60-minute PowerPoint oral health educational seminar given to the paediatric and family medicine residents. STATISTICS: Multiple-choice items were used and the pre- and post-test data were analysed with McNemar and Wilcoxon signed-rank tests. A p-value <0.05 was considered statistically significant. RESULTS: Sixty-eight residents participated in the oral health educational seminar and completed the questionnaire. The mean age of participants was 29.9 years old (SD ±4.8 yrs.). Immediately following a 60-minute oral health educational seminar, there was an overall significant increase in participants' knowledge, attitudes and likelihood towards incorporating oral health preventive practice in their current practices to well-child visits (p<0.05). More confidence in identifying and referring patients with dental trauma was reported by 100% of participants. CONCLUSIONS: A 60-minute oral health educational seminar was effective in improving paediatric and family medicine residents' immediate knowledge, attitude, and likelihood towards incorporating oral health preventive practice in their current practices to well-child visits. Significantly more residents felt more confident in identifying and referring patients with dental trauma. Key messages: an oral health educational seminar can be effective in improving paediatric and family medicine residents' immediate knowledge, attitude, and likelihood towards incorporating oral health preventive practice in their current practices to well-child visits.

Microbiota of severe early childhood caries before and after therapy.

Severe early childhood caries (ECC) is difficult to treat successfully. This study aimed to characterize the microbiota of severe ECC and evaluate whether baseline or follow-up microbiotas are associated with new lesions post-treatment. Plaque samples from 2- to 6-year-old children were analyzed by a 16S rRNA-based microarray and by PCR for selected taxa. Severe-ECC children were monitored for 12 months post-therapy. By microarray, species associated with severe-ECC (n = 53) compared with caries-free (n = 32) children included Slackia exigua (p = 0.002), Streptococcus parasanguinis (p = 0.013), and Prevotella species (p < 0.02). By PCR, severe-ECC-associated taxa included Bifidobacteriaceae (p < 0.001), Scardovia wiggsiae (p = 0.003), Streptococcus mutans with bifidobacteria (p < 0.001), and S. mutans with S. wiggsiae (p = 0.001). In follow-up, children without new lesions (n = 36) showed lower detection of taxa including S. mutans, changes not observed in children with follow-up lesions (n = 17). Partial least-squares modeling separated the children into caries-free and two severe-ECC groups with either a stronger bacterial or a stronger dietary component. We conclude that several species, including S. wiggsiae and S. exigua, are associated with the ecology of advanced caries, that successful treatment is accompanied by a change in the microbiota, and that severe ECC is diverse, with influences from selected bacteria or from diet.

The quality of life among coronary heart disease patients at a teaching hospital.

BACKGROUND AND AIMS: Quality of life after acute coronary heart disease amongst patients is important outcome factor in deliberations of patient's care. The main aim of the study was to examine the quality of life amongst acute CHD patients. MATERIALS AND METHODS: A cross sectional descriptive study was conducted after an acute attack amongst coronary heart disease (CHD) patients in Universiti Kebangsaan Malaysia Medical Centre (UKMMC).The Medical Outcomes Short Form 36 (SF-36) comprised of 36 items used to measure quality of life which comprised of 4 domains of physical component summary were physical function, role physical, bodily pain, and general health and 4 domains of mental component summary were vitality, social function, emotional role, and mental health. A total of 108 respondents were recruited for this study. RESULTS: The findings showed that CHD. Respondents possessed good level of quality of life with total score of (59 ± 22). The total score of physical domain had mean and SD of 56 ± 24, while the total scores of the mental domain had mean and SD of 62 ± 27. There were significant differences between the general health components of quality of life with educational status of the CHD patients with (F= 5.433, p<0.05). There were significant differences in role physical components of quality of life with income (F= 3.144, p<0.05). CONCLUSION: The cardiac rehabilitation program would have deliberately improved their needs and conditions whilst hospitalization. These results have implications in which CHD patients should be evaluated with regard to their continuity of care.

Cultivable anaerobic microbiota of severe early childhood caries.

Severe early childhood caries (ECC), while strongly associated with Streptococcus mutans using selective detection (culture, PCR), has also been associated with a widely diverse microbiota using molecular cloning approaches. The aim of this study was to evaluate the microbiota of severe ECC using anaerobic culture. The microbial composition of dental plaque from 42 severe ECC children was compared with that of 40 caries-free children. Bacterial samples were cultured anaerobically on blood and acid (pH 5) agars. Isolates were purified, and partial sequences for the 16S rRNA gene were obtained from 5,608 isolates. Sequence-based analysis of the 16S rRNA isolate libraries from blood and acid agars of severe ECC and caries-free children had >90% population coverage, with greater diversity occurring in the blood isolate library. Isolate sequences were compared with taxon sequences in the Human Oral Microbiome Database (HOMD), and 198 HOMD taxa were identified, including 45 previously uncultivated taxa, 29 extended HOMD taxa, and 45 potential novel groups. The major species associated with severe ECC included Streptococcus mutans, Scardovia wiggsiae, Veillonella parvula, Streptococcus cristatus, and Actinomyces gerensceriae. S. wiggsiae was significantly associated with severe ECC children in the presence and absence of S. mutans detection. We conclude that anaerobic culture detected as wide a diversity of species in ECC as that observed using cloning approaches. Culture coupled with 16S rRNA identification identified over 74 isolates for human oral taxa without previously cultivated representatives. The major caries-associated species were S. mutans and S. wiggsiae, the latter of which is a candidate as a newly recognized caries pathogen.

Estimation of glomerular filtration rate using serum cystatin C in overweight and obese subjects.

BACKGROUND: Obesity and overweight are strong independent risk factors for chronic kidney disease (CKD). Using serum creatinine-based estimated glomerular filtration rate (eGFR) equations in these subjects may be inaccurate. On the other hand, cystatin C-based eGFR equations may overestimate CKD prevalence as recent findings suggest an association of cystatin C with obesity. The objective of this study was to assess the accuracy of a cystatin C-based eGFR equation compared to two creatinine -based eGFR equations in overweight and obese subjects. METHODS: This was a prospective cross-sectional study which recruited healthy volunteers aged 18-55 years with a body mass index (BMI) > or = 23kg/m(2) (Asia Pacific Guidelines). Their renal profiles, serum cystatin C and 99m technetium diethylene triamine pentacetic acid (99)mTc-DTPA) scans were performed on the same day. The correlations and accuracy of the creatinine-based and cystatin C-based eGFR equations with the (99)mTc-DTPA GFR were determined. RESULTS: One hundred and one subjects with a median age of 30.0 (27.0-43.5) years and mean BMI of 28.7 +/- 4.5 kg/m(2) were recruited. The cystatin C-based eGFR equation showed the best correlation with the (99)mTc-DTPA GFR (r = 0.526, p = 0.001) and was more accurate in measuring abnormal GFR compared to the creatinine-based eGFR equations. CONCLUSION: Our study showed that the cystatin C-based eGFR equation was more accurate, sensitive and specific in overweight and obese subjects compared to the creatinine-based eGFR equations.

Diet and caries-associated bacteria in severe early childhood caries.

Frequent consumption of cariogenic foods and bacterial infection are risk factors for early childhood caries (ECC). This study hypothesized that a short diet survey focused on frequency of foods, categorized by putative cariogenicity, would differentiate severe ECC (S-ECC) from caries-free children. Children's diets were obtained by survey and plaque bacteria detected by PCR from 72 S-ECC and 38 caries-free children. S-ECC children had higher scores for between-meal juice (p < 0.01), solid-retentive foods (p < 0.001), eating frequency (p < 0.005), and estimated food cariogenicity (p < 0.0001) than caries-free children. S-ECC children with lesion recurrence ate fewer putative caries-protective foods than children without new lesions. Streptococcus mutans (p < 0.005), Streptococcus sobrinus (p < 0.005), and Bifidobacteria (p < 0.0001) were associated with S-ECC, and S. mutans with S. sobrinus was associated with lesion recurrence (p < 0.05). S. mutans-positive children had higher food cariogenicity scores. Food frequency, putative cariogenicity, and S. mutans were associated with S-ECC individually and in combination.

Clonal analysis of the microbiota of severe early childhood caries.

BACKGROUND/AIMS: Severe early childhood caries is a microbial infection that severely compromises the dentition of young children. The aim of this study was to characterize the microbiota of severe early childhood caries. METHODS: Dental plaque samples from 2- to 6-year-old children were analyzed using 16S rRNA gene cloning and sequencing, and by specific PCR amplification for Streptococcus mutans and Bifidobacteriaceae species. RESULTS: Children with severe caries (n = 39) had more dental plaque and gingival inflammation than caries-free children (n = 41). Analysis of phylotypes from operational taxonomic unit analysis of 16S rRNA clonal metalibraries from severe caries and caries-free children indicated that while libraries differed significantly (p < 0.0001), there was increased diversity than detected in this clonal analysis. Using the Human Oral Microbiome Database, 139 different taxa were identified. Within the limits of this study, caries-associated taxa included Granulicatella elegans (p < 0.01) and Veillonella sp. HOT-780 (p < 0.01). The species associated with caries-free children included Capnocytophaga gingivalis (p < 0.01), Abiotrophia defectiva (p < 0.01), Lachnospiraceae sp. HOT-100 (p < 0.05), Streptococcus sanguinis (p < 0.05) and Streptococcus cristatus (p < 0.05). By specific PCR, S. mutans (p < 0.005) and Bifidobacteriaceae spp. (p < 0.0001) were significantly associated with severe caries. CONCLUSION: Clonal analysis of 80 children identified a diverse microbiota that differed between severe caries and caries-free children, but the association of S. mutans with caries was from specific PCR analysis, not from clonal analysis, of samples.

Randomised, open label, controlled trial of celecoxib in the treatment of acute migraine.

INTRODUCTION: Migraine is a common disabling condition that results in considerable socioeconomic loss. The role of non-steroidal anti-inflammatory drugs (NSAIDs) in acute migraine has been well-established. We compared the efficacy of the cyclooxygenase-2 inhibitor celecoxib with the NSAID, naproxen sodium, in the treatment of acute migraine. METHODS: This was a randomised, open label, controlled trial. We selected patients with a diagnosis of migraine, based on the International Headache Society revised criteria. 60 patients were randomised to either celecoxib 400 mg (30 patients) or naproxen sodium 550 mg (30 patients). Patients took the study medicine for the first acute migraine episode that occurred during the study period and reported the headache reduction based on a visual analogue score (VAS). Patients were reviewed after a month to check on VAS at one and two hours, compared to the baseline. Any side effects of the medication were also recorded. RESULTS: Of the 52 patients who completed the study, eight did not experience any headaches. The mean VAS in the celecoxib group improved significantly from baseline (6.48 +/- 1.53) to one hour (4.28 +/- 2.11) and two hours (2.24 +/- 2.57) (p-value is less than 0.0005). The mean VAS in the naproxen sodium group also improved significantly from baseline (7.30 +/- 1.66) to one hour (4.81 +/- 2.50) and two hours (2.63 +/- 2.65) (p-value is less than 0.0005). However, there was no significant difference between the magnitudes of improvement between the treatment groups. The incidence of gastric pain was significantly higher in the naproxen sodium group (p-value is equal to 0.029). CONCLUSION: In comparison with naproxen sodium, celecoxib was equally effective in relieving pain in acute migraine and caused significantly less gastric pain.

Short QTc in epilepsy patients without cardiac symptoms.

Epilepsy patients have a higher mortality rate than the general population. Sudden unexpected death in epilepsy (SUDEP) is a major cause of mortality for these patients. The possibility of cardiac involvement in the pathogenesis of SUDEP has been suggested by many previous studies. This study compared the QT interval in epilepsy patients and normal controls, and identified the factors that affected the QT interval. Standard 12-lead ECGs were recorded from 70 consecutive epilepsy patients from the neurology clinic of HUKM and 70 age, race and gender matched controls. The mean QT interval corrected for heart rate (QTc) was calculated and compared. The mean QTc among the epilepsy patients was 0.401 +/- 0.027s. It was significantly shorter than the QTc (0.420 +/- 0.027s) in the control group (p<0.0005). Thirty five epilepsy patients (50%) and 17 matched controls (24.3%) had a mean QTc shorter than 0.40s (p=0.001). Among the epilepsy patients, the mean QTc did not significantly differ between patients in the duration (F=0.836, p=0.438) of the epilepsy, frequency (F=0.273, p=0.845) and types of seizures (p=0.633). There was no significant difference in the mean QTc between the epilepsy patients on different number of antiepileptic agents (F=0.444, p=0.643). Patients with cryptogenic epilepsy had a mean QTc of 0.392 +/- 0.029s, which was significantly shorter than patients with symptomatic epilepsy (QTc = 0.410 +/- 0.027s, p = 0.015). The mean QTc of the same subjects showed no significant interobserver difference (p=0.661). This study, for the first time, demonstrates that epilepsy patients have a significantly shorter QTc than controls, particularly in the subgroup of patients with cryptogenic epilepsy.

Mutational analysis of the adcCBA genes in Streptococcus gordonii biofilm formation.

Streptococcus gordonii, a primary colonizer, is part of the pioneer biofilm consortium that initiates dental plaque development on tooth surfaces. An insertion of Tn917-lac transposon into the adcR gene produced a biofilm-defective phenotype. S. gordonii adcR is a regulatory gene and is part of an operon (adc) that includes three other genes, adcCBA. AdcC contains a putative consensus-binding site for adenosine triphosphate, AdcB is a putative hydrophobic membrane protein, and AdcA is a putative lipoprotein permease. Mutants were constructed by insertional inactivation in each of the three adcCBA genes and their effects on biofilm formation examined. The adcC::spec(R) and adcB::spec(R) mutations displayed a biofilm-defective phenotype, whereas the adcA::spec(R) mutant was biofilm-positive in a static polystyrene microtiter plate biofilm assay. All three mutants formed poor biofilms in a flow-cell system and were competence-defective, suggesting the adc operon plays an important role in S. gordonii biofilm formation and competence.

Role of a nosX homolog in Streptococcus gordonii in aerobic growth and biofilm formation.

Oral streptococci such as Streptococcus gordonii are facultative anaerobes that initiate biofilm formation on tooth surfaces. An isolated S. gordonii::Tn917-lac biofilm-defective mutant contained a transposon insertion in an open reading frame (ORF) encoding a homolog of NosX of Ralstonia eutropha, a putative maturation factor of nitrous oxide reductase. Located downstream are two genes, qor1 and qor2, predicted to encode two putative NADPH quinone oxidoreductases. These three genes are cotranscribed, forming a putative oxidative stress response (osr) operon in S. gordonii. Inactivation of nosX, qor1, or qor2 resulted in biofilm-defective phenotypes. Expression of nosX, measured by the beta-galactosidase activity of the nosX::Tn917-lac mutant, was growth-phase dependent and enhanced when grown under aerobic conditions or in the presence of paraquat. Real-time reverse transcription-PCR revealed that nosX-specific mRNA levels were increased approximately 8.4 and 3.5 fold in biofilm-derived cells grown on plastic and glass, respectively, when compared to planktonic cells. Expression of nosX increased 19.9 fold in cells grown under aerated aerobic conditions and 4.7 fold in cells grown under static aerobic conditions. Two ORFs immediately adjacent to the osr operon encode a putative NADH oxidase (Nox) and a putative thiol-specific antioxidant enzyme (AhpC, for alkyl hydroperoxide peroxidase C). Expression of nox and ahpC was also significantly increased in cells grown under aerated and static aerobic conditions when compared to anaerobic conditions. In addition, nox expression was increased in biofilm cells compared to planktonic cells. These genes may be part of an island that deals with oxidoreductive response, some of which may be important in S. gordonii biofilm formation.

Role of a Streptococcus gordonii copper-transport operon, copYAZ, in biofilm detachment.

Streptococcus gordonii is a pioneer oral bacterium that is associated with the initiation of dental plaque development. Located downstream of the S. gordonii adc operon, which is involved in competence and biofilm formation, were three open reading frames, designated copY, copA and copZ. These open reading frames were homologous to the copYAZ genes in Streptococcus mutans that are involved in copper homeostasis and biofilm detachment. This study examined whether copYAZ genes play any role in the biofilm formation and detachment of S. gordonii. The copY gene encodes a 143-amino acid protein homologous to the negative transcriptional regulator of a copper-transport operon, copA encodes a 748-amino acid copper-transporting P-type ATPase, and copZ encodes a 69-amino acid putative metallochaperone protein in S. mutans. Each open reading frame in the copYAZ operon in S. gordonii was inactivated by insertional mutation and the growth, biofilm formation and detachment of each mutant were examined. S. gordonii copY::specR, copA::specR, and copZ::specR mutants were able to form biofilms on both polystyrene and glass surfaces. However, inactivation of copZ and to a lesser extent copY resulted in phenotypes that were defective in biofilm detachment, which is consistent with previous observations in S. mutans and suggests that the trace element copper might influence biofilm detachment of bacterial biofilms.

Involvement of an inducible fructose phosphotransferase operon in Streptococcus gordonii biofilm formation.

Oral streptococci, such as Streptococcus gordonii, are the predominant early colonizers that initiate biofilm formation on tooth surfaces. Investigation of an S. gordonii::Tn917-lac biofilm-defective mutant isolated by using an in vitro biofilm formation assay showed that the transposon insertion is near the 3' end of an open reading frame (ORF) encoding a protein homologous to Streptococcus mutans FruK. Three genes, fruR, fruK, and fruI, were predicted to encode polypeptides that are part of the fructose phosphotransferase system (PTS) in S. gordonii. These proteins, FruR, FruK, and FruI, are homologous to proteins encoded by the inducible fruRKI operon of S. mutans. In S. mutans, FruR is a transcriptional repressor, FruK is a fructose-1-phosphate kinase, and FruI is the fructose-specific enzyme II (fructose permease) of the phosphoenolpyruvate-dependent sugar PTS. Reverse transcription-PCR confirmed that fruR, fruK, and fruI are cotranscribed as an operon in S. gordonii, and the transposon insertion in S. gordonii fruK::Tn917-lac resulted in a nonpolar mutation. Nonpolar inactivation of either fruK or fruI generated by allelic replacement resulted in a biofilm-defective phenotype, whereas a nonpolar mutant with an inactivated fruR gene retained the ability to form a biofilm. Expression of fruK, as measured by the beta-galactosidase activity of the fruK::Tn917-lac mutant, was observed to be growth phase dependent and was enhanced when the mutant was grown in media with high levels of fructose, sucrose, xylitol, and human serum, indicating that the fructose PTS operon was fructose and xylitol inducible, similar to the S. mutans fructose PTS. The induction by fructose was inhibited by the presence of glucose, indicating that glucose is able to catabolite repress fruK expression. Nonpolar inactivation of the fruR gene in the fruK::Tn917-lac mutant resulted in a greater increase in beta-galactosidase activity when the organism was grown in media supplemented with fructose, confirming that fruR is a transcriptional repressor of the fructose PTS operon. These results suggest that the regulation of fructose transport and metabolism in S. gordonii is intricately tied to carbon catabolite control and the ability to form biofilms. Carbon catabolite control, which modulates carbon flux in response to environmental nutritional levels, appears to be important in the regulation of bacterial biofilms.

Cloning and expression of alpha-D-glucosidase and N-acetyl-beta-glucosaminidase from the periodontal pathogen, Tannerella forsythensis (Bacteroides forsythus).

Screening a genomic library of Tannerella forsythensis (Bacteroides forsythus), using synthetic substrates conjugated to a fluorogen, 4-methylumbelliferone identified two glycosidase genes, which encode alpha-D-glucosidase and N-acetyl-beta-D-glucosaminidase, respectively. The alpha-D-glucosidase has a Mr of 81,141 and is homologous to an alpha-D-glucosidase from Bacteroides thetaiotaomicron. The N-acetyl-beta-D-glucosaminidase has a Mr of 87,787 and is homologous to an N-acetyl-beta-D-glucosaminidase in Porphyromonas gingivalis W83.

Involvement of the adc operon and manganese homeostasis in Streptococcus gordonii biofilm formation.

Pioneer oral bacteria, including Streptococcus gordonii, initiate the formation of oral biofilms on tooth surfaces, which requires differential expression of genes that recognize unique environmental cues. An S. gordonii::Tn917-lac biofilm-defective mutant was isolated by using an in vitro biofilm formation assay. Subsequent inverse PCR and sequence analyses identified the transposon insertion to be near the 3' end of an open reading frame (ORF) encoding a protein homologous to a Streptococcus pneumoniae repressor, AdcR. The S. gordonii adc operon, consisting of the four ORFs adcR, adcC, adcB, and adcA, is homologous to the adc operon of S. pneumoniae, which plays a role in zinc and/or manganese transport and genetic competence in S. pneumoniae. AdcR is a metal-dependent repressor protein containing a putative metal-binding site, AdcC contains a consensus-binding site for ATP, AdcB is a hydrophobic protein with seven hydrophobic membrane-spanning regions, and AdcA is a lipoprotein permease with a putative metal-binding site. The three proteins (AdcC through -A) are similar to those of the binding-lipoprotein-dependent transport system of gram-positive bacteria. Reverse transcriptase PCR confirmed that adcRCBA are cotranscribed as an operon in S. gordonii and that the transposon insertion in S. gordonii adcR::Tn917-lac had resulted in a polar mutation. Expression of adcR, measured by the beta-galactosidase activity of the adcR::Tn917-lac mutant, was growth phase dependent and increased when the mutant was grown in media with high levels of manganese (>1 mM) and to a lesser extent in media with zinc, indicating that AdcR may be a regulator at high levels of extracellular manganese. A nonpolar inactivation of adcR generated by allelic replacement resulted in a biofilm- and competence-defective phenotype. The biofilm-defective phenotype observed suggests that AdcR is an active repressor when synthesized and acts at a distant site(s) on the chromosome. Thus, the adc operon is involved in manganese acquisition in S. gordonii and manganese homeostasis and appears to modulate sessile growth in this bacterium.

Streptococcus gordonii biofilm formation: identification of genes that code for biofilm phenotypes.

Viridans streptococci, which include Streptococcus gordonii, are pioneer oral bacteria that initiate dental plaque formation. Sessile bacteria in a biofilm exhibit a mode of growth that is distinct from that of planktonic bacteria. Biofilm formation of S. gordonii Challis was characterized using an in vitro biofilm formation assay on polystyrene surfaces. The same assay was used as a nonbiased method to screen isogenic mutants generated by Tn916 transposon mutagenesis for defective biofilm formation. Biofilms formed optimally when bacteria were grown in a minimal medium under anaerobic conditions. Biofilm formation was affected by changes in pH, osmolarity, and carbohydrate content of the growth media. Eighteen biofilm-defective mutants of S. gordonii Challis were identified based on Southern hybridization with a Tn916-based probe and DNA sequences of the Tn916-flanking regions. Molecular analyses of these mutants showed that some of the genes required for biofilm formation are involved in signal transduction, peptidoglycan biosynthesis, and adhesion. These characteristics are associated with quorum sensing, osmoadaptation, and adhesion functions in oral streptococci. Only nine of the biofilm-defective mutants had defects in genes of known function, suggesting that novel aspects of bacterial physiology may play a part in biofilm formation. Further identification and characterization of biofilm-associated genes will provide insight into the molecular mechanisms of biofilm formation of oral streptococci.

Fibronectin binding by Streptococcus milleri group strains and partial characterisation of the fibronectin receptor of Streptococcus anginosus F4.

The Streptococcus milleri group were shown to bind fibronectin (Fn) to their cell-surface and this binding increased the adhesion of cells to hydroxyapatite. The binding of Fn to Streptococcus anginosus F4 was studied in more detail. Fn binding to bacterial cells increased the association of the bacteria with the polymorphonuclear leukocytes obtained from the peritoneal cavity of rats but did not increase killing of the bacteria. The cell-surface receptor was a protein of M(r) 14,000 which was released from cells after mutanolysin digestion. The binding was specific, with cells having a maximum number of binding sites per cell of 770. Electron microscopy, using gold-labelled Fn, localised the receptor to areas between daughter cells.

Surface-associated properties of Actinomyces strains and their potential relation to pathogenesis.

Twenty-nine strains from the Actinomyces species were tested for a range of surface properties. Results show considerable heterogeneity both between different species and within some of the species, especially Actinomyces naeslundii. Two commonly used A. naeslundii strains, T14V and ATCC 12104, fell within the low (salivary aggregation and collagen binding by T14V), moderate (surface charge and haemagglutination) or high range of values (hydrophobicity, saliva-coated hydroxyapatite adhesion, polystyrene binding by T14V, fibrinogen binding by T14V and collagen binding by A. naeslundii ATCC 12104). Both strains adhered well to saliva-coated hydroxyapatite; T14V bound the highest amount of fibrinogen, ATCC 12104 had the highest number of cells bound to collagen and T14V was not bound at all. The heterogeneity of these characteristics highlights the need to include a range of strains of Actinomyces in studies on their pathogenicity. Statistical correlations were found between a number of properties, for example saliva-coated hydroxyapatite adhesion and hydrophobicity, and between haemagglutination and hydrophobicity.

Albumin-binding proteins on the surface of the Streptococcus milleri group and characterization of the albumin receptor of Streptococcus intermedius C5.

Members of the Streptococcus milleri group (SMG) that react with Lancefield group C antisera were shown to bind large amounts of albumin although there was no direct relation between these two properties as polyclonal antisera to Lancefield group C antigen did not prevent the binding of albumin. There was a specificity for albumin binding, with albumin from man, monkeys, cat, dog and mouse being bound to a greater degree than albumin from cow, horse, goat or rabbit. Gold-labelled albumin was shown to be located close to the surface of strains by transmission electron microscopy. A cell-surface protein of M(r) 24,000, which was liberated by lysozyme treatment of cells, was shown to be the cell-surface receptor on Streptococcus intermedius C5. The receptor was physically dissimilar from protein G, an albumin- and IgG-binding protein of 'large-colony' Lancefield group C and G streptococci.

Coaggregation of oral lactobacilli with streptococci from the oral cavity.

The ability of oral lactobacilli to coaggregate with streptococci and actinomycetes was investigated. Of the 7 species of lactobacilli studied, only two were capable of coaggregation and the coaggregation was restricted to streptococci. Lactobacillus salivarius strains (2/4) coaggregated with Streptococcus salivarius, Streptococcus gordonii, Streptococcus crista and tufted Streptococcus sanguis II strains. Lactobacillus fermentum (2/3) coaggregated with S. gordonii and S. sanguis. The coaggregation between L. salivarius and S. salivarius, S. gordonii or tufted S. sanguis II strains was mediated by a protein on the surface of the lactobacilli and was not inhibited by lactose. The coaggregation between L. fermentum and the streptococci was mediated by protein on the surface of the streptococci and was inhibited by lactose.