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

BACKGROUND: Porphyromonas gingivalis is the foremost oral pathogen of adult periodontitis in humans. However, the mechanisms of bacterial invasion and the resultant destruction of the gingival tissue remain largely undefined. RESULTS: We report host-P. gingivalis interactions in primary human gingival fibroblast (HGF) cells. Quantitative immunostaining revealed the need for a high multiplicity of infection for optimal infection. Early in infection (2–12 h), P. gingivalis activated the proinflammatory transcription factor NF-kappa B, partly via the PI3 kinase/AKT pathway. This was accompanied by the induction of cellular anti-apoptotic genes, including Bfl-1, Boo, Bcl-XL, Bcl2, Mcl-1, Bcl-w and Survivin. Late in infection (24–36 h) the anti-apoptotic genes largely shut down and the pro-apoptotic genes, including Nip3, Hrk, Bak, Bik, Bok, Bax, Bad, Bim and Moap-1, were activated. Apoptosis was characterized by nuclear DNA degradation and activation of caspases-3, -6, -7 and -9 via the intrinsic mitochondrial pathway. Use of inhibitors revealed an anti-apoptotic function of NF-kappa B and PI3 kinase in P. gingivalis-infected HGF cells. Use of a triple protease mutant P. gingivalis lacking three major gingipains (rgpA rgpB kgp) suggested a role of some or all these proteases in myriad aspects of bacteria-gingival interaction. CONCLUSION: The pathology of the gingival fibroblast in P. gingivalis infection is affected by a temporal shift from cellular survival response to apoptosis, regulated by a number of anti- and pro-apoptotic molecules. The gingipain group of proteases affects bacteria-host interactions and may directly promote apoptosis by intracellular proteolytic activation of caspase-3

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

Physicians' communication skills with patients and legal liability in decided medical malpractice litigation cases in Japan

<p>Abstract</p> <p>Background</p> <p>In medical malpractice litigations in recent years in Japan, it is notable that the growing number of medical litigation cases includes the issue of a doctor's explanation to the patient as a pivotal point. The objective of this study was to identify factors of physicians' communication skills with patients, as related to their legal liability, and differences in doctors' communication skills with patients by the type of medical facility.</p> <p>Methods</p> <p>Decisions of medical malpractice litigation cases between 1988 and 2005 in Japan, the pivotal issue of which was a physician's explanation, were analyzed in the study. The content of each decision was summarized using the study variables (information about the patient, doctor, manner of the doctor's explanation, and subsequent litigation), and a database comprising the content of each decision (<it>N </it>= 100) was constructed. In order to evaluate an association between doctors' communication skills with patients and the outcome of the litigation, the analysis was performed based on the outcome of litigation or the type of medical facility.</p> <p>Results</p> <p>The ratio of acknowledged physician liability by court decision was lower in cases in which the doctor's explanation occurred before treatment or surgery (<it>p </it>= 0.013). The ratio of acknowledged physician liability by court decision was higher in cases of elective or non-urgent treatment (<it>p </it>= 0.046). The ratio of acknowledged physician liability by court decision was higher in clinics than in hospital groups (<it>p </it>= 0.036).</p> <p>Conclusion</p> <p>These findings are beneficial for the prevention of medical disputes and improvement of patient-physician communication.</p

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

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>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.</p> <p>Results</p> <p>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.</p> <p>Conclusion</p> <p>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.</p

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

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>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.</p> <p>Results</p> <p>There were significant differences between the levels of CH₃SCH₃and 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 CH₃SCH₃and severe MPB in subjects with gastrointestinal diseases, hypertension, and hypercholesterolemia.</p> <p>Conclusion</p> <p>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.</p

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Use of the Genomic Subtractive Hybridization Technique To Develop a Real-Time PCR Assay for Quantitative Detection of Prevotella spp. in Oral Biofilm Samples

Genomic subtractive hybridization was used to design Prevotella nigrescens-specific primers and TaqMan probes. Based on this technique, a TaqMan real-time PCR assay was developed for quantifying four oral black-pigmented Prevotella species. The combination of real-time PCR and genomic subtractive hybridization is useful for preparing species-specific primer-probe sets for closely related species