Retraction Note: Temporal activation of anti- and pro-apoptotic factors in human gingival fibroblasts infected with the periodontal pathogen, Porphyromonas gingivalis: potential role of bacterial proteases in host signalling.

The Editor has retracted this article [1] following an investigation by the University of South Alabama which found.

Relationship between tooth loss and mortality in 80-year-old Japanese community-dwelling subjects.

BACKGROUND: Findings from several studies suggest associations between tooth loss and health outcomes, including malnutrition, poor quality of life, and mortality, in older individuals. However, limited information is available regarding whether those associations remain true in very elderly subjects after adequately considering confounding factors such as sex and smoking status. Herein, we determined whether the number of teeth in 80-year-old subjects is an independent predictor of mortality. METHODS: We initially contacted 1282 80-year-old community-dwelling individuals born in 1917, of whom 697 responded and participated in a baseline study, with follow-up examinations conducted 4 and 5.5 years later. Data from interviews and medical and oral examinations were obtained, and oral health was determined according to the number of teeth remaining in the oral cavity. RESULTS: A total of 108 and 157 subjects died in 4 years and 5.5 years, respectively, after the baseline study. Tooth loss was significantly associated with mortality at age 85.5, but not at age 84, after adjusting for potential confounders. When the analysis was stratified by sex, we found a stronger association in females in follow-up examinations conducted at both 4- and 5.5 years. On the other hand, the effect of tooth loss on mortality was not significantly different between smokers and non-smokers. CONCLUSION: Tooth loss is a significant predictor of mortality independent of health factors, socio-economic status, and lifestyle in octogenarians, with a stronger association in females.

A study of the efficacy of ultrasonic waves in removing biofilms.

OBJECTIVE: The removal of adherent biofilms was assessed using ultrasonic waves in a non-contact mode. MATERIALS AND METHODS: In in vitro experiments, Streptococcus mutans (S. mutans) biofilms were exposed to ultrasonic waves at various frequencies (280 kHz, 1 MHz, or 2 MHz), duty ratios (0-90%), and exposure times (1-3 minutes), and the optimal conditions for biofilm removal were identified. Furthermore, the effect of adding a contrast medium, such as micro bubbles (Sonazoid), was examined. The spatial distribution and architecture of S. mutans biofilms before and after ultrasonic wave exposure were examined via scanning electron microscopy. The biofilm removal effect was also examined in in vivo experiments, using a custom-made oral cleaning device. RESULTS: When a 280 kHz probe was used, the biofilm-removing effect increased significantly compared to 1 and 2 MHz probes; more than 80% of the adherent biofilm was removed with a duty cycle of 50-90% and a 3 minutes exposure time. The maximum biofilm-removing effect was observed with a duty cycle of 80%. Furthermore, the addition of micro bubbles enhanced this biofilm-removing effect. In in vivo experiments, moderate biofilm removal was observed when a 280 kHz probe was used for 5 minutes. CONCLUSIONS: This study demonstrated that ultrasonic wave exposure in a non-contact mode effectively removed adherent biofilms composed of S. mutans in vitro.

Serum albumin levels as an independent predictor of 4-year mortality in a community-dwelling 80-year-old population.

BACKGROUND AND AIMS: Although serum albumin levels are associated with mortality in non-institutionalized elderly people under 80 years old, as well as in the institutionalized very elderly, little is known about the relationship in community-dwelling very elderly people. We, therefore, examined the association in a Japanese population of 80-year-old community residents. METHODS: Serum albumin levels were measured in 672 (267 men, 405 women) out of 1282 80-year-old individuals. Over the following 4 years, the dates and causes of death were recorded from resident registration cards and official death certificates. RESULTS: Of the above individuals, 107 subjects died (58 men, 49 women: 27 due to cancer, 27 cardiovascular disease, and 22 pneumonia). Survival rates were compared among 4 groups (highest >or=45 g/L, higher than 43-44 g/L, lower than 41-42 g/L, lowest

Rapid LED-based fluorescence microscopy distinguishes between live and dead bacteria in oral clinical samples.

Despite the existence of several methods for the diagnosis of oral infectious diseases, few rapid and quantitative methods exist for discriminating between live and dead bacterial cells in oral clinical samples. In this study, we characterized a light-emitting diode (LED) fluorescence microscopic technique for quantifying live and dead oral bacterial cells stained with 4',6'-deamidino-2-phenyllindole and propidium iodide. Four bacterial strains representative of the human oral microflora were used in this study. In addition, saliva and subgingival fluid specimens were collected from healthy volunteers. Saliva was obtained from the donors without stimulation, whereas subgingival fluid was obtained by inserting a sterile endodontic paper point into the subgingival sites of the first molar. The samples were cultured on agar plates and subjected to LED microscopy. The correlations between both methods were analyzed. The number of live bacterial cells as determined by LED-based fluorescence microscopy and standard colony counts on agar plates correlated well for the known oral bacterial strains and bacterial cells in the clinical specimens. The LED illumination method characterized in this study can be used for the rapid enumeration of living and dead cells. However, to show specificity, this method requires further innovations.

The identification of genes specific to Prevotella intermedia and Prevotella nigrescens using genomic subtractive hybridization.

Prevotella intermedia and Prevotella nigrescens, which are often isolated from periodontal sites, were once considered two different genotypes of P. intermedia. Although the genomic sequence of P. intermedia was determined recently, little is known about the genetic differences between P. intermedia and P. nigrescens. The subtractive hybridization technique is a powerful method for generating a set of DNA fragments differing between two closely related bacterial strains or species. We used subtractive hybridization to identify the DNA regions specific to P. intermedia ATCC 25611 and P. nigrescens ATCC 25261. Using this method, four P. intermedia ATCC 25611-specific and three P. nigrescens ATCC 25261-specific regions were determined. From the species-specific regions, insertion sequence (IS) elements were isolated for P. intermedia. IS elements play an important role in the pathogenicity of bacteria. For the P. intermedia-specific regions, the genes adenine-specific DNA-methyltransferase and 8-amino-7-oxononanoate synthase were isolated. The P. nigrescens-specific region contained a Flavobacterium psychrophilum SprA homologue, a cell-surface protein involved in gliding motility, Prevotella melaninogenica ATCC 25845 glutathione peroxide, and Porphyromonas gingivalis ATCC 33277 leucyl-tRNA synthetase. The results demonstrate that the subtractive hybridization technique was useful for distinguishing between the two closely related species. Furthermore, this technique will contribute to our understanding of the virulence of these species.

Quality of life and physical fitness in an 85-year-old population.

Since little is known about the very elderly population aged 80 years and older, we evaluated the association of quality of life (QoL) in an 85-year-old population with physical fitness measurements assessed at age 80 and 85 years. Two hundred seven individuals (90 males, 117 females) aged 85 years underwent the Short Form-36 (SF-36) questionnaires for QoL assessment and physical fitness measurements (handgrip strength, leg-extensor strength, one-leg standing time, stepping rate of legs, walking speed). In 85-year-olds, significant associations were found, by multiple regression analysis or logistic regression analysis, with adjustment for various influencing factors in QoL assessed by SF-36 with physical fitness measurements examined at the age of 85 and 80 years. Physical scales and scores in SF-36, such as physical functioning (PF), limitation in role functioning for physical reasons (role physical; RP), bodily pain (BP), and the physical component score (PCS) tended to be more tightly associated with fitness measurements than mental scales and scores such as limitation in role functioning for emotional reasons (role emotional; RE), and emotional well-being (mental health; MH), and mental component score (MCS). Three scales the general health perceptions (GH), the vitality (VT), and the social functioning (SF) consisting of both physical and mental components were associated with fitness, the extent being intermediate between physical scales and mental scales. Of the several physical fitness measurements, leg-extensor strength and the walking speed of 85-year-olds, and the stepping rate of 80-year-olds were most closely associated with QoL. In a very elderly population of 85- and 80-year-olds, significant associations were found between QoL by SF-36 and physical fitness measurements, suggesting that increases in the levels of physical fitness, even in the very elderly, can contribute to improvements in QoL.

Does decreased diastolic blood pressure associate with increased mortality in 80-year-old Japanese?

Hypertension is one of the greatest risk factors for cardiovascular disease, but its contribution to cardiovascular mortality weakens with aging. We have previously demonstrated that at the age of 80, higher systolic blood pressure (SBP) is not correlated with increased mortality in Japan. However, we did not examine in detail whether diastolic blood pressure (DBP) independently affects mortality. In the present study, 639 participants, who were 80 years old in 1997, were enrolled. The subjects were divided by their DBP [below 70 mmHg (group 1, n = 136), from 70 mmHg to 80 mmHg (group 2, n = 200), from 80 mmHg to 90 mmHg (group 3, n = 194), over 90 mmHg (group 4, n = 109)]. During the 4-year follow-up period, 90 individuals died. Cox multivariate regression analysis revealed that group 1 showed a significantly higher mortality rate than group 4 [relative risk (RR) 2.47, confidence interval (CI) 1.07-5.70, p = 0.03)]. The relative risks of deaths from cardiovascular diseases, pneumonia, and cancer tended to be higher in group 1 than in group 4, but the difference did not reach statistical significance. These results suggest that decreased DBP is associated with higher mortality in the Japanese elderly.

Hydrogen sulfide production from cysteine and homocysteine by periodontal and oral bacteria.

BACKGROUND: Hydrogen sulfide is one of the predominant volatile sulfur compounds (VSCs) produced by oral bacteria. This study developed and evaluated a system for detecting hydrogen sulfide production by oral bacteria. METHODS: L-methionine-alpha-deamino-gamma-mercaptomethane-lyase (METase) and beta carbon-sulfur (beta C-S) lyase were used to degrade homocysteine and cysteine, respectively, to produce hydrogen sulfide. Enzymatic reactions resulting in hydrogen sulfide production were assayed by reaction with bismuth trichloride, which forms a black precipitate when mixed with hydrogen sulfide. The enzymatic activities of various oral bacteria that result in hydrogen sulfide production and the capacity of bacteria from periodontal sites to form hydrogen sulfide in reaction mixtures containing L-cysteine or DL-homocysteine were assayed. RESULTS: With L-cysteine as the substrate, Streptococcus anginosus FW73 produced the most hydrogen sulfide, whereas Porphyromonas gingivalis American Type Culture Collection (ATCC) 33277 and W83 and Fusobacterium nucleatum ATCC 10953 produced approximately 35% of the amount produced by the P. gingivalis strains. Finally, the hydrogen sulfide found in subgingival plaque was analyzed. Using bismuth trichloride, the hydrogen sulfide produced by oral bacteria was visually detectable as a black precipitate. CONCLUSIONS: Hydrogen sulfide production by oral bacteria was easily analyzed using bismuth trichloride. However, further innovation is required for practical use.

Possible association of atrophic gastritis and arterial stiffness in healthy middle-aged Japanese.

AIM: Helicobacter pylori (HP) has been implicated as a risk factor for cardiovascular and atherosclerotic diseases. Arterial stiffness determined by pulse wave velocity (PWV) or the cardio-ankle vascular index (CAVI) has been shown to be higher in HP-positive subjects than in HP-negative subjects; however, this result has been observed only in young subjects. The aim of the study was to investigate the possible correlation between HP infection and PWV or CAVI in middle-aged subjects. METHODS: We measured brachial-ankle PWV (baPWV), CAVI, metabolism markers, pepsinogens (PGs) and IgG antibody to HP in 343 individuals aged either 60 or 65 year old. Atrophic gastritis (AG) was diagnosed based on the values of PGs. RESULTS: baPWV and CAVI were significantly higher in the AG-positive group than in the AG-negative group even after adjusting for possible confounding factors (baPWVc; 16.63+/-3.50 vs. 15.59+/-3.47 p=0.010, CAVIc; 8.59+/-1.20 vs. 8.27+/-1.19 p=0.022). baPWV and CAVI values tended to be higher in the HP-positive group than in the HP-negative group. High-density lipoprotein (HDL) cholesterol level and the adiponectin level were lower in the AG-positive group than in the AG-negative group. CONCLUSION: There may be an association between atrophic gastritis and atherosclerosis in middle-aged subjects.

Salivary levels of hyaluronic acid in female patients with dry mouth compared with age-matched controls: a pilot study.

Little is known regarding the association between the level of hyaluronic acid (HA) in saliva and dry mouth status. The aim of this study was to evaluate the salivary levels of HA in female patients with dry mouth (perceived xerostomia and hyposalivation) and compare them with age-matched controls. We studied 46 females, and classified them into two groups based on perceived xerostomia and salivary flow rate, as well as a control group without symptoms. HA concentrations in unstimulated whole saliva were determined and a significant difference was found between the groups. The statistical association was stronger in patients (perceived xerostomia, normosalivation) administrated xerogenic drugs, while the HA levels in that group were significantly lower than those in the controls when converted to absolute amount of saliva per min. Within the limitations of the present study, patients with dry mouth had lower HA levels in saliva, which may serve as a marker of local dryness or oral mucosa lubrication.

Associations among hair loss, oral sulfur-containing gases, and gastrointestinal and metabolic linked diseases in Japanese elderly men: pilot study.

BACKGROUND: Male pattern baldness (MPB), an observable trait, has been reported to be associated with various diseases, such as prostate cancer and cardiovascular disease. Oral sulfur-containing gases have also been suggested to be useful as markers of systemic health condition. However, there are no known reports regarding the associations among MPB, and oral sulfur-containing gases, and systemic health conditions in males. METHODS: We studied 170 male subjects aged either 60 or 65 years old. The degree of MPB was assessed using the Norwood-Hamilton Baldness scale. Oral sulfur-containing gases were measured using a compact-designed device. All subjects completed physical and laboratory blood examinations, a face-to-face medical questionnaire, and an oral examination. RESULTS: There were significant differences between the levels of CH3SCH3 and baldness patterns, independent of age. When we analyzed whether the association was linked to systemic health condition, a strong significant association was observed between the level of CH3SCH3 and severe MPB in subjects with gastrointestinal diseases, hypertension, and hypercholesterolemia. CONCLUSION: These results suggest that MPB is associated with the level of CH3SCH3, a sulfur-containing gas that causes oral malodor, in elderly Japanese males. Further, the association was intensified by the existence of gastrointestinal tract and metabolic disorders.

IgA level is associated with risk for mortality in an eighty-year-old population.

BACKGROUND: Immunoglobulin levels are elevated in the older people. However, it is unknown whether these levels are related to mortality. OBJECT: To evaluate the association between immunoglobulin levels and mortality. METHODS: The study population included 697 individuals (277 males and 420 females) of 1,282 eighty-year-old individuals residing in the Fukuoka prefecture, Japan. The participants were followed for 4 years after the baseline examination. RESULTS: The hyper-IgA group, defined as a serum IgA level >400 mg/dl, had high mortality using Kaplan-Meier analysis (log rank, p=0.037). Multivariate Cox regression analyses revealed a high risk of mortality (hazard rate=1.233, 95% confidence interval 1.109-1.491, p=0.031) after adjusting for covariates. The high risk of mortality in the hyper-IgA group was significant in males, but not in females. Moreover, Kaplan-Meier analysis revealed that IgA was related to cancer mortality in males (log rank, p=0.031), but not to pneumonia or cardiovascular disease. IgM and IgG levels were not related to high risk of mortality. CONCLUSION: Serum IgA levels appear to be a predictor of mortality, especially cancer mortality in males.

Relationship between root caries and alveolar bone loss in the first wet-rice agriculturalists of the Yayoi period in Japan.

OBJECTIVE: The people of the Yayoi period (5th C b.c.-3rd C a.d.), who were the first wet-rice agriculturalists in ancient Japan, had carious lesions that were most frequently located on the root surfaces of their teeth. Root surface exposure is a prerequisite for this type of decay, and alveolar bone loss is the main cause of such exposure. Therefore, we identify the factors associated with root caries, and examine the relationship between root caries and alveolar bone loss in the people of the Yayoi period. MATERIALS AND METHODS: This study was performed using 263 sets of ancient skeletal remains that are believed to be from the Yayoi period and that were excavated at 49 archaeological sites in western Japan. Using 5010 teeth found among the remains, we analysed the relationship between the prevalence of root caries and the cemento-enamel junction-alveolar crest (CEJ-AC) distance. RESULTS: The prevalence of root caries and the mean number of teeth with root caries per person were significantly correlated with age, the presence of coronal caries and the mean CEJ-AC distance per person. We also found that as the mean CEJ-AC distance per tooth surface increased, the percentage of the root surface affected by caries increased. Moreover, after excluding the lingual (palatal) side, the mean CEJ-AC distance per surface was significantly greater for those tooth surfaces with root caries. CONCLUSION: We present the first evidence that the occurrence of root caries correlated with the CEJ-AC distance in the Yayoi people of Japan.

Relationship between endothelin-1 and interleukin-1beta in inflamed periodontal tissues.

We recently demonstrated that endothelin-1 (ET-1) was strongly expressed in inflamed gingival tissues, but the biological role of ET-1 in gingival tissue remains unknown. This study focused on the relationship between ET-1 and interleukin-1beta (IL-1beta), an important cytokine during the periodontal inflammatory process. We determined the protein levels of ET-1 and IL-1beta in gingival tissues from patients and examined whether ET-1 could regulate the expression of the IL-1beta gene and protein in oral epithelial cells and fibroblasts in vitro. There was a significant correlation between the levels of ET-1 and IL-1beta in 26 gingival tissues, as determined by ELISA. Following the confirmation of two specific ET-1 receptors (ETA and ETB receptors) on the cultured cells, the effects of ET-1 stimulation on IL-1beta mRNA and protein expression were evaluated by RT-PCR and ELISA, respectively. The IL-1beta mRNA and protein levels were enhanced by ET-1 stimulation in a dose-dependent manner, and the enhancement of IL-1beta was inhibited by ETA or ETB receptor antagonists. These findings indicate that ET-1 is involved in the regulation of IL-1beta expression in gingival tissues and suggest that ET-1 signaling to the cells may be a therapeutic target for treating IL-1beta-dependent inflammatory responses.

Determination of cortisol and dehydroepiandrosterone levels in saliva for screening of periodontitis in older Japanese adults.

Background. Recent reports have found a positive relationship between periodontitis and the hormones cortisol and dehydroepiandrosterone (DHEA). We investigated the associations between those levels and periodontitis in never-smokers and smokers of elderly subjects. Subjects and Methods. Cortisol and DHEA levels in saliva were determined in 171 subjects (85 males, 86 females), with clinical examinations including probing depth (PD) and clinical attachment loss (CAL) also performed. Results. Smoking had effects on cortisol and DHEA levels, and those were significantly associated with severe PD and CAL in never-smokers. According to ROC analysis, the cutoff values of cortisol and DHEA to obtain the optimal sensitivity and specificity for detecting severe periodontitis were 2.06 ng/mL and 60.24 pg/mL, respectively, for PD, and 2.12 ng/mL and 61.78 pg/mL, respectively, for CAL. Conclusions. Assessment of hormone levels may be a useful screening method for periodontitis, though limited to never-smokers.

Chronic kidney disease increases cardiovascular mortality in 80-year-old subjects in Japan.

Chronic kidney disease (CKD) is one of the greatest risk factors for cardiovascular disease (CVD). The contribution of CKD to CVD mortality is not well understood in very elderly patients. Our study examined whether CKD might be a risk factor for total and CVD mortality in very elderly Japanese individuals. A total of 621 participants were enrolled, all of whom were 80 years old. The subjects were divided on the basis of the presence (CKD(+) group, n=280) or absence (CKD(-) group, n=341) of CKD. CKD was defined by as an estimated glomerular filtration rate (eGFR) below 60 mL/min/1.73 m(2). The eGFR of the CKD(+) and CKD(-) groups was 49.7+/-8.5 and 70.9+/-9.5 mL/min/1.73 m(2), respectively. During the 4-year study period, 87 individuals died, and 25 of those deaths were due to CVD. A Cox multivariate regression analysis revealed no association between total mortality and CKD (relative risk [RR] 1.17, confidence interval [CI] 0.75-1.82, p=0.50). However, the CVD mortality was significantly increased in the CKD(+) group (RR 4.60, CI 1.69-12.52, p=0.003). CKD significantly increased the CVD mortality in subjects who were not taking antihypertensive medication (RR 5.15, CI 1.04-25.50, p=0.04). Our results suggest that CKD increases the risk of CVD mortality in very elderly individuals. It is not only important to prevent progression toward CKD in patients who do not suffer from CKD, but also critical to manage the risk factors for CVD in patients with CKD, despite their advanced age. (Hypertens Res 2008; 31: 2053-2058).

Atrophic gastritis, but not antibody to Helicobacter pylori, is associated with body mass index in a Japanese population.

BACKGROUND: The relationship between Helicobacter pylori (HP) infection and body mass index (BMI) is controversial. Several reports have indicated that eradication of HP infection induces an increase in BMI. In contrast, epidemiological case-control studies have failed to show an association between HP infection and BMI. Therefore, we investigated whether HP and atrophic gastritis (AG) were associated with BMI. METHODS: A total of 617 individuals were recruited for the measurements of BMI, serum leptin, pepsinogens (PGs) I and II, and IgG antibody to HP (HP-IgG). BMI and leptin of the subjects were compared when the subjects were stratified by HP-IgG and PGs. RESULTS: The subjects were divided into AG-positive and AG-negative groups according to PGs (AG-positive: PG I < or = 70 ng/ml and PG I/II ratio < or =3.0). BMI after adjusting for sex and age was significantly lower in the AG-positive group than in the AG-negative group (23.47 +/- 3.05 vs. 24.18 +/- 3.25, P = 0.010). When the subjects were divided into two groups according to HP-IgG, BMI tended to be lower in the HP-IgG-positive group, though the difference was not large. When the subjects were divided into four groups for different combinations of AG and HP-IgG, BMI was the lowest in the AG-positive and HP-IgG-negative group. CONCLUSIONS: BMI was associated with AG, as diagnosed by PGs, but not with HP infection status. These results mean that HP infection affects BMI via atrophic gastritis.

Salivary levels of cortisol and chromogranin A in patients with dry mouth compared with age-matched controls.

OBJECTIVE: To evaluate the salivary levels of cortisol and chromogranin A (CgA) in patients with dry mouth (perceived xerostomia and hyposalivation) compared with age-matched controls. STUDY DESIGN: We studied 174 subjects, including those with dry mouth, classified into 2 subgroups based on perceived xerostomia and salivation, and those without (control subjects). The control subjects were patients at the same hospital and healthy volunteers. Cortisol and CgA levels in stimulated whole saliva were measured using ELISA kits. RESULTS: All subjects with dry mouth had significantly higher cortisol and CgA levels than the control subjects. The statistical associations remained significant when they were divided into the 2 subgroups, although somewhat weaker associations were observed. The influences of xerogenic drugs were found to be minimal on salivary flow rate and levels of cortisol and CgA. CONCLUSIONS: We found significant associations between salivary cortisol and CgA levels and symptoms of oral dryness and reduced salivary flow.

Association of cortisol and dehydroepiandrosterone sulphate levels in serum with periodontal status in older Japanese adults.

BACKGROUND AND AIM: The associations between periodontitis and stress-related steroid hormone levels released by the hypothalamic-pituitary-adrenal axis are poorly understood. In this study, we examined the association between levels of the stress-related steroid hormones cortisol and dehydroepiandrosterone-sulphate (DHEAS) and periodontitis in elderly subjects. METHODS: A total of 467 subjects participated in this study. Serum cortisol and DHEAS levels were determined, and a medical questionnaire regarding medical conditions and lifestyle was administered. In addition, clinical examinations including probing depth (PD), bleeding on probing (BOP), and clinical attachment loss (CAL) were conducted. RESULTS: The subjects were divided into tertiles on the basis of periodontitis severity. When the analysis was stratified by smoking status, we found that cortisol levels were significantly higher in those with severe CAL among subjects who had never smoked. Furthermore, multiple regression analysis showed that a higher level of cortisol was significantly associated with greater numbers of sites with severe CAL only in those who had never smoked, while a somewhat weaker association was also observed regarding cortisol/DHEAS ratio. In contrast, the level of DHEAS in serum was not associated with periodontitis. CONCLUSION: There were significant associations between serum cortisol level, including cortisol/DHEAS ratio, and periodontitis severity in elderly subjects who had never smoked.