Heterogeneity of human serum antibody responses to P. gingivalis in periodontitis: Effects of age, race/ethnicity, and sex.

Aging humans display an increased prevalence and severity of periodontitis, although the mechanisms underlying these findings remain poorly understood. This report examined antigenic diversity of P. gingivalis related to disease presence and patient demographics. Serum IgG antibody to P. gingivalis strains ATCC33277, FDC381, W50 (ATCC53978), W83, A7A1-28 (ATCC53977) and A7436 was measured in 426 participants [periodontally healthy (n = 61), gingivitis (N = 66) or various levels of periodontitis (N = 299)]. We hypothesized that antigenic diversity in P. gingivalis could contribute to a lack of "immunity" in the chronic infections of periodontal disease. Across the strains, the antibody levels in the oldest age group were lower than in the youngest groups, and severe periodontitis patients did not show higher antibody with aging. While 80 % of the periodontitis patients in any age group showed an elevated response to at least one of the P. gingivalis strains, the patterns of individual responses in the older group were also substantially different than the other age groups. Significantly greater numbers of older patients showed strain-specific antibody profiles to only 1 strain. The findings support that P. gingivalis may demonstrate antigenic diversity/drift within patients and could be one factor to help explain the inefficiency/ineffectiveness of the adaptive immune response in managing the infection.

Methodology to estimate the break force of pharmaceutical tablets with curved faces under diametrical compression.

This paper develops a methodology to estimate the break force of curved faced tablets under diametrical compression. Common excipients used in pharmaceutical tablet formulations, including microcrystalline cellulose, calcium phosphate and mannitol as well as their mixtures were characterised. Compacts of different densities were manufactured and their compressive and tensile strength was measured. The break force of curved face tablets having a comprehensive range of face curvatures and thickness was measured using the diametrical compression method ("hardness" test). Equation σd=FπD2atD+bWD-1 introduced by Shang et al. (2013) was used to relate the break force (F) to tablet geometry (D, t, W) and material tensile strength (σd). Here, we propose a method to estimate the parameters a and b using data for flat faced tablets. The method was validated for four mixtures. The errors were analysed and compared with the USP29 method σd=10FπD2(2.84(t/D)-0.126t/W+3.15(W/D)+0.01)-1. The proposed method has better accuracy, however, requires additional characterisation of the compressive strength of the material.

Cross-talk between clinical and host-response parameters of periodontitis in smokers.

BACKGROUND AND OBJECTIVE: Periodontal diseases are a major public health concern leading to tooth loss and have also been shown to be associated with several chronic systemic diseases. Smoking is a major risk factor for the development of numerous systemic diseases, as well as periodontitis. While it is clear that smokers have a significantly enhanced risk for developing periodontitis leading to tooth loss, the population varies regarding susceptibility to disease associated with smoking. This investigation focused on identifying differences in four broad sets of variables, consisting of: (i) host-response molecules; (ii) periodontal clinical parameters; (iii) antibody responses to periodontal pathogens and oral commensal bacteria; and (iv) other variables of interest, in a population of smokers with (n = 171) and without (n = 117) periodontitis. MATERIAL AND METHODS: Bayesian network structured learning (BNSL) techniques were used to investigate potential associations and cross-talk between the four broad sets of variables. RESULTS: BNSL revealed two broad communities with markedly different topology between the populations of smokers, with and without periodontitis. Confidence of the edges in the resulting network also showed marked variations within and between the periodontitis and nonperiodontitis groups. CONCLUSION: The results presented validated known associations and discovered new ones with minimal precedence that may warrant further investigation and novel hypothesis generation. Cross-talk between the clinical variables and antibody profiles of bacteria were especially pronounced in the case of periodontitis and were mediated by the antibody response profile to Porphyromonas gingivalis.

Relaxor Ferroelectrics: Back to the Single-Soft-Mode Picture.

The fluctuations of electric polarization in a disordered ferroelectric substance, relaxor crystal PbMg_{1/3}Nb_{2/3}O_{3} (PMN), were studied using a nonlinear inelastic light-scattering technique, hyper-Raman scattering, within a 5-100 cm^{-1} spectral interval and in a broad temperature range from 20 to 900 K. The split ferroelectric mode reveals a local anisotropy of up to about 400 K. Spectral anomalies observed at higher temperatures are explained as due to avoided crossing of the single primary polar soft mode with a temperature-independent, nonpolar spectral feature near 45 cm^{-1}, known from Raman scattering. The temperature changes of the vibrational modes involved in the measured fluctuation spectra of PMN were captured in a simple model that accounts for the temperature dependence of the dielectric permittivity as well. The observed slowing down of the relaxational dynamics directly correlates with the huge increase of the dielectric permittivity.

Rapid assessment of salivary MMP-8 and periodontal disease using lateral flow immunoassay.

OBJECTIVE: The objective of this study was to determine the efficacy of a novel point-of-care immunoflow device (POCID) for detecting matrix metalloproteinase (MMP)-8 concentrations in oral fluids in comparison with a gold standard laboratory-based immunoassay. METHODS: Oral rinse fluid and whole expectorated saliva samples were collected from 41 participants clinically classified as periodontally healthy or diseased. Samples were analyzed for MMP-8 by Luminex immunoassay and POCID. Photographed POCID results were assessed by optical scan and visually by two examiners. Data were analyzed by Pearson's correlation and receiver-operating characteristics. RESULTS: MMP-8 was readily detected by the POCID, and concentrations correlated well with Luminex for both saliva and rinse fluids (r = 0.57-0.93). Thresholds that distinguished periodontitis from health were delineated from both the optical scans and visual reads of the POCID (sensitivity: 0.7-0.9, specificity: 0.5-0.7; P < 0.05). CONCLUSIONS: Performance of this POCID for detecting MMP-8 in oral rinse fluid or saliva was excellent. These findings help demonstrate the utility of salivary biomarkers for distinguishing periodontal disease from health using a rapid point-of-care approach.

Smoking-related cotinine levels and host responses in chronic periodontitis.

BACKGROUND AND OBJECTIVE: Smoking has been reported to increase the risk of periodontal disease by disrupting the balance of immune responses and tissue repair processes; however, this risk varies among smokers. Cotinine levels in saliva are routinely used to measure the level of smoking, and reflect the quantity of nicotine, and other smoking-related xenobiotics that challenge host systems. This study delineated characteristics of inflammatory mediators in saliva and serum antibody responses to both periodontal pathogens and commensal bacteria in smokers as they related to cotinine levels. MATERIALS AND METHODS: This case-control study (n = 279) examined salivary inflammatory mediator responses [interleukin (IL)-1ß, IL-10, prostaglandin E2, myeloperoxidase and plasminogen activator inhibitor-1], and serum IgG antibody responses to three periodontal pathogens (Aggregatibacter actinomyce-temcomitans, Porphyromonas gingivalis, Treponema denticola) and five commensal oral microorganisms (Veillonella parvula, Streptococcus sanguis, Prevotella loescheii, Actinomyces naeslundii, Capnocytophaga ochracea). RESULTS: The patients were stratified into health (n = 30), gingivitis (n = 55) and periodontitis (n = 184); cotinine levels correlated with reported smoking habits in health, less so with gingivitis, and were not correlated in periodontitis. Of the inflammatory mediators/acute phase proteins, only IL-1ß levels were positively associated (p < 0.001) with the pack years and cotinine levels. As might be predicted, patients with periodontitis smoked more (p < 0.001) and had higher levels of cotinine. IL-1ß and antibody to A. actinomycetemcomitans, P. gingivalis and T. denticola were significantly higher in the patients with periodontitis than either patients with gingivitis or who were healthy. CONCLUSIONS: Generally, antibody to the pathogens and commensals was lower with decreased cotinine levels. Smoking exacerbated differences in both inflammatory mediators and three antibody in periodontal disease compared to healthy subjects.

Bone remodeling-associated salivary biomarker MIP-1α distinguishes periodontal disease from health.

BACKGROUND AND OBJECTIVE: The field of salivary diagnostics lacks an accepted and validated biomarker of alveolar bone remodeling. To address this, we examined levels of salivary biomolecules specifically associated with biological aspects of bone remodeling in subjects with chronic periodontitis in a case-control study. MATERIAL AND METHODS: Levels of macrophage inflammatory protein-1α (MIP-1α), osteoprotegerin, C-telopeptide pyridinoline cross-links of type I collagen and ß-C-terminal type I collagen telopeptide in unstimulated whole saliva of 80 subjects (40 subjects with moderate to severe chronic periodontitis and 40 sex- and age-matched healthy control subjects) were measured using enzyme immunosorbent assays. Saliva was collected before clinical examination, which included probing depth, clinical attachment loss and bleeding on probing. RESULTS: The mean level of MIP-1α in subjects with periodontitis was 18-fold higher than in healthy subjects (p < 0.0001). Clinical periodontal indices correlated significantly with MIP-1α levels (p < 0.0001). Of the biomolecules examined, MIP-1α demonstrated the greatest ability to discriminate between periodontal disease and health as determined by the area under the curve (0.94) and classification and regression tree analysis (sensitivity 94% and specificity 92.7%). Osteoprotegerin levels were elevated 1.6-fold (p = 0.055), whereas C-telopeptide pyridinoline cross-links of type I collagen and ß-C-terminal type I collagen telopeptide levels were below the level of detection in the majority of subjects. CONCLUSION: These findings suggest that the chemokine MIP-1α may aid in identifying periodontitis. Future longitudinal studies are warranted to determine whether this biomarker can help in ascertaining the progression of bone loss in subjects with periodontal disease.

Dentinal hypersensitivity: review of aetiology, differential diagnosis, prevalence, and mechanism.

Dentinal hypersensitivity is a painful response to a non-noxious stimulus applied to exposed dentine in the oral environment. Dentine exposure results from a combination of two or more aetiological factors that lead to loss of enamel and/or loss of cementum. The hydrodynamic theory is the most accepted theory that explains the excitement of pulpal nerve fibres by a stimulus applied to the exposed dentine. Dentinal hypersensitivity had been reported to affect middle age people most often with no gender differences and has been shown to be influenced by tooth location.

Pulmonary arterial histology and morphometry in systemic sclerosis: a case-control autopsy study.

Morphometric measurements were performed on pulmonary arteries in 58 patients with systemic sclerosis (20 limited cutaneous and 38 diffuse cutaneous involvement [21 with and 17 without renal crisis]) and age, race, and sex matched autopsy controls. Matched pairs analysis was employed. For arteries of all sizes, the area of the intima and percent luminal occlusion were greater in the limited and diffuse (no renal crisis) groups than in controls, and these differences were statistically significant for large and medium sized vessels. The greatest luminal occlusion was found in limited cutaneous patients, and especially those with clinical evidence of pulmonary arterial hypertension, providing a rationale for the poor response to vasodilator therapy in these patients.

Renal vascular histology and morphometry in systemic sclerosis. A case-control autopsy study.

An autopsy case-control study of renal vascular histology and morphometry in systemic sclerosis (scleroderma) was performed. Thirty-five of 70 systemic sclerosis cases had renal tissue available for study: 26 had diffuse cutaneous involvement (9 with "renal crisis" and 17 without) and 9 had limited cutaneous disease (CREST syndrome [calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, telangiectasias]). Age-matched (within 10 years) and sex-matched controls with renal specimens were obtained. New sections were cut from tissue blocks, and morphometry was completed using a Zeiss Image Analyzer. Using analysis of variance, the intimal area (Ai) was significantly increased (intimal thickening) in small and medium-sized arteries of patients with diffuse scleroderma and in small arteries of CREST patients, compared with those in controls, while a decreased medial area (Am) was seen consistently in all groups. The proportion of the vessel wall occupied by intima (Ai:[Ai + Am]) was significantly greater in all vessel size groups in patients with diffuse scleroderma compared with that in controls. The percentage of luminal occlusion was greatest in patients with diffuse disease with renal crisis. These same patients had severe edematous and mucinous intimal thickening in small and medium vessels, often in association with fibrinoid necrosis. We conclude that renal vascular structural changes are an integral part of systemic sclerosis. However, the significant differences between diffuse scleroderma patients and CREST syndrome patients, for both intimal thickening and percentage of luminal occlusion, suggest that the arterial disease in these 2 patient subsets is distinctive.