Relationship between smoking status and periodontal conditions: findings from national databases in Japan.

BACKGROUND AND OBJECTIVE: The association between cigarette smoking and periodontitis was examined employing two nationally representative samples of adults in Japan. MATERIAL AND METHODS: Data were derived from the Survey of Dental Diseases (SDD) and the National Nutrition Survey (NNS) in 1999. In the SDD, periodontal conditions were evaluated by calibrated dentists utilizing the Community Periodontal Index (CPI), whereas in the NNS, participants were interviewed on the basis of smoking status by enumerators. Among 6805 records electronically linked via a household identification code, 4828 records of individuals aged 20 yr or older were analyzed. RESULTS: The prevalence of periodontal disease varied significantly by smoking status (p < 0.0001): 39.3%, 49.5% and 47.3% (CPI > or = 3), and 7.9%, 11.7% and 12.4% (a more severe form of periodontitis, CPI = 4), for nonsmokers, former smokers and current smokers, respectively. In adults aged > or = 40 yr (n = 3493), logistic regression models revealed greater probabilities (approximately 1.4 times higher) of periodontitis [CPI > or = 3, odds ratio = 1.38 (1.12-1.71), p = 0.0024] and a more severe form of periodontitis [odds ratio = 1.40 (1.04-1.89), p = 0.0288] in current smokers compared with nonsmokers, following adjustment for possible confounding factors. CONCLUSION: Based on the findings of this study and other numerous reports, cigarette smoking leads to deterioration of periodontal conditions in Japanese adults.

Systemic diseases in association with microbial species in oral biofilm from elderly requiring care.

BACKGROUND: The oral cavity is a reservoir for colonization and infection of systemic organs by pathogenic bacteria. It is understood that aging, tooth eruption, hormonal changes, active disease, oral hygiene, and other factors have an influence on biofilm formation and bacterial accumulation in the oral cavity. OBJECTIVE: To understand the influence of systemic health care on microfloral changes, we conducted epidemiological studies of nursing home residents in an attempt to elucidate the relationship between underlying systemic diseases and the isolation frequency of oral opportunistic pathogens. METHODS: The prevalence of bacteria and fungi causing pneumonia in association with oral biofilm bacteria were determined using detection culture plates. The influences of gender, age, denture-wearing status, number of teeth, and bedridden status in the patients residing in nursing homes were then analyzed. RESULTS: The isolation frequency rates of Candida albicans, Pseudomonadaceae, Staphylococcus spp., and some strains of Enterobacteriaceae in plaque samples, as well as C. albicans and Xanthomonas maltophilia in samples from the pharynx, were significantly higher in those requiring systemic care (mean age 83.9 years) than in those who did not require such care (mean 71.0 years). In particular, the frequencies of Pseudomonas spp., C. albicans, and Serratia marcescens in plaque were significantly higher in those who were bedridden. Furthermore, the isolation of Pseudomonas spp. and Klebsiella pneumoniae, and/or C. albicans in plaque was significantly associated with heart disease. CONCLUSION: The coexistence of Pseudomonas spp. and C. albicans in elderly with 10-19 teeth is a potential indicator of high risk for pneumonia and heart disease. Therefore, attention to oral hygiene and professional care for removing the indicators may diminish the occurrence of systemic disease in the elderly requiring systemic care.

Binding of hemoglobin by Porphyromonas gingivalis.

In this study, we investigated whether Porphyromonas gingivalis can bind hemoglobin as an initial step in the acquisition of heme from hemoglobin. The binding of human hemoglobin by P. gingivalis cells was determined using [3H]hemoglobin. Hemoglobin binding occurred rapidly, reversibly and specifically. A Scatchard analysis of the binding data generated a linear plot, indicating a single population of binding proteins. The apparent Kd was 1.0 +/- 0.19 x 10(-6) M and there were 3.2 +/- 0.76 x 10(4) binding sites per cell. Hemoglobin binding was inhibited by unlabeled human hemoglobin but not by hemin and protoporphyrin IX. The binding was only partially inhibited by human serum albumin, transferrin, lactoferrin, catalase and cytochrome c. These results suggest that the ligand recognized by the binding protein may not be the heme moiety. The binding of hemoglobin considerably increased when the organisms were grown under hemin-limited conditions. Hemoglobin bound to outer membrane proteins extracted from P. gingivalis cells on a dot blot binding assay and binding ability was lost after heating bacterial proteins. These results suggest that P. gingivalis cells interact with human hemoglobin through specific binding sites on their surfaces as a preliminary step in iron acquisition.

Interaction of Porphyromonas gingivalis with transferrin.

In this study, we characterized the binding of transferrin to Porphyromonas gingivalis using a classical receptor-binding assay, and examined the relationship between the binding and availability of transferrin for the growth of P. gingivalis. The binding of 125I-labeled human transferrin to P. gingivalis occurred rapidly, reversibly and specifically. Scatchard analysis yielded a Kd of 1.37 +/- 0.16 microM and an apparent number of 1.13 +/- 0.26 x 10(5) receptors per cell. The binding of transferrin was much increased when organisms were grown in iron-limited conditions. Among the species of black-pigmented anaerobic.rods, those strains of P. gingivalis which had high transferrin-binding activity exhibited unrestricted growth following the addition of transferrin to the hemin-free culture medium. On the other hand, the presence of transferrin in the culture medium did not support unrestricted growth of organisms that had low transferrin-binding activity. These results suggest that the binding of transferrin to P. gingivalis cells may be a preliminary step in iron acquisition, which allows them to survive in the healthy periodontal environment.

Effect of concentration of compounds containing iron on the growth of Porphyromonas gingivalis.

We examined the effect of the concentration of various types of iron molecules on the regulation of growth of Porphyromonas gingivalis. Bacterial growth was monitored spectrophotometrically. The hemin-depleted cells of P. gingivalis 381 were incubated in the basal medium plus test substrates such as hemoglobin, hemin, transferrin and various inorganic iron compounds. The relationship between the specific growth rate of organisms and the concentration of iron-containing compounds was determined. The value of Ks, a parameter analogous to the Michaelis-Menten constant, was estimated. P. gingivalis 381 showed a Ks value of 3.85, 4.91 and 0.0017 microM for hemin, transferrin and hemoglobin, respectively. However, the inorganic iron compounds tested did not support growth of P. gingivalis. These findings suggest that P. gingivalis utilizes hemoglobin as an iron source much more effectively than other iron-containing compounds under an iron-limited environment.

Changes in oxygen consumption in dog gingiva during induction of experimental periodontitis.

The purpose of this study was to examine changes in oxygen consumption in dog gingiva during induction of experimental periodontitis. The disease was induced in adult mongrel dogs during a 16-week period by placement of silk ligatures around selected teeth. The oxygen consumption rate of gingival tissue was determined in vivo by a non-invasive technique, tissue reflectance spectrophotometry. Changes in such clinical parameters as gingival index, plaque index, pocket depth, attachment level, and gingival crevicular fluid flow indicated acute inflammatory responses during the first three weeks after ligation, followed by the appearance of chronic inflammation during the remaining 13 weeks. The oxygen consumption rate increased during the first seven days after ligation and stayed near the maximum level for 2-7 weeks; this was followed by a gradual decrease during the final nine weeks. These results suggest that gingival oxygen consumption increases rapidly with the increase of acute inflammation responses and then decreases slightly with the gradual development of chronic inflammation. Positive correlations were observed between the oxygen consumption rate and other clinical indices. Thus, the tissue reflectance spectrophotometry is a new, useful method for objective, quantitative, and non-invasive assessment of gingival oxygen consumption.

Effect of transferrin on the growth of Porphyromonas gingivalis.

This study describes the effect of transferrin as an iron source on the growth of Porphyromonas (formally Bacteroides) gingivalis. Bacterial growth was monitored spectrophotometrically. All strains of P. gingivalis tested grew well in medium containing transferrin. The growth of P. gingivalis depended not only on the concentration of transferrin, but also on the iron saturation level of the protein. However, growth was not stimulated with either the ferrous or ferric iron salts tested. The addition of dipyridyl to the medium containing transferrin suppressed the growth of P. gingivalis, which also did not show species-specificity for human transferrin. Transferrin-binding activity was found in P. gingivalis by solid-phase assay with peroxidase-conjugated human transferrin. These results suggest that P. gingivalis may be capable of utilizing transferrin as an iron source for growth in vivo.

Inhibitory effect of human plasma and saliva on co-aggregation between Bacteroides gingivalis and Streptococcus mitis.

The effect of human plasma and saliva on co-aggregation between Bacteroides gingivalis and Streptococcus mitis was studied by means of a turbidimetric assay. The co-aggregation activity was obtained from the maximum slope of the absorbance vs. time curve. Its dependence on pH, temperature, and ionic strength was examined, and the number of Bacteroides cells in relation to the number of Streptococcus cells resulting in optimal co-aggregation was established. Co-aggregation inhibition experiments showed that the co-aggregation activity was inhibited by l-arginine and l-lysine, although the activity was unaffected by the sugars tested. Human plasma and saliva were able to inhibit the co-aggregation in a dose-dependent reaction. Plasma exhibited the most potent inhibitory activity in these fluids. Fibrinogen was the most potent inhibitor of the plasma-derived proteins tested. These data suggest the possibility that the oral fluids may modulate the attachment of B. gingivalis to Gram-positive bacteria in periodontal pockets.

Purification and some properties of fucosyltransferase in human parotid saliva.

Fucosyltransferase was purified from human parotid saliva by affinity chromatography on GDP-hexanolamine Sepharose, followed by chromatofocusing on PBE 94 exchanger gel. The purified enzyme had the N-acetyglucosaminide alpha 1----4, the N-acetylglucosaminide alpha 1----3, and the glucoside alpha 1----3 fucosyltransferase activities. The molecular weight of the purified enzyme was estimated to be approximately 20,000. These enzyme activities showed identical pH and divalent metal ion dependencies and identical rates of inactivation upon being heated. The paper chromatographic analysis of the fucosylated products by the purified enzyme and the susceptibility of these products to linkage-specific fucosidase digestion indicated that the transferase formed the Fuc alpha 1----4GlcNAc, Fuc alpha 1----3GlcNAc, and Fuc alpha 1----3Glc linkages.

Isolation and some properties of exohemagglutinin from the culture medium of Bacteroides gingivalis 381.

Exohemagglutinin was found in the culture medium of Bacteroides gingivalis 381. Exohemagglutinin was purified 3,150-fold from culture fluid by ultracentrifugation followed by gel filtration on Sepharose CL-4B and by affinity chromatography on arginine-agarose. Examination of the final preparation of exohemagglutinin by biochemical analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the isolated exohemagglutinin contained three major proteins but not a detectable lipopolysaccharide. Hemagglutination inhibition experiments showed that the activity of exohemagglutinin was inhibited by L-arginine and the arginine-containing peptides, although the activity was unaffected by the sugars tested. Some protein and glycoproteins that were examined also exhibited the inhibitory activity. When the bovine submaxillary mucin was chemically modified by beta-elimination and bovine serum albumin was modified by guanidination, the inhibitory effects on hemagglutination were significantly enhanced. These results suggest that the hemagglutination of the isolated exohemagglutinin may be involved in arginine residues as components of ligand-binding sites on erythrocytes.

The presence of fucosyltransferases with different substrate specificity in human parotid saliva.

Using glycoproteins and milk oligosaccharides as substrate acceptors, we demonstrated at least two fucosyltransferases in human parotid saliva. One enzyme transferred L-fucose from GDP-fucose to the C-3 position of N-acetylglucosamine or glucose residue of oligosaccharide chains, and the other transferred to the C-4 position of N-acetylglucosamine residue of oligosaccharide chains.