A Proposal of a Novel Method for Generating Discrete Analog Uniform Noise

This paper presents a proposal of a new way to generate analog noise, discrete in time, with uniform probability density function. Instead of the usual way of generating discrete analog uniform noise using a uniform pseudorandom number generator and a digital-to-analog converter, generating based on non-equidistant sampling of sawtooth voltage is suggested. The original hardware structure that implements this idea is suggested and its work is simulated. The simulations have confirmed the validity of the idea. The main gain is the unlimited resolution of the analog output of the uniform noise generator suggested. The resolution of standard uniform noise generators is limited by the resolution of the digital-to-analog converter used

Immunomodulatory Activity of IL-27 in Human Periapical Lesions

IL-27, a cytokine with pro-inflammatory and anti-inflammatory properties, is a new member of the IL-6/IL-12 family, whose function in periapical lesions is unknown. We hypothesized that the production of IL-27 and its effect depend upon the type of immune/inflammatory response and clinical presentation of periapical lesions. We tested this hypothesis by studying the expression and function of IL-27 in human periapical lesions, both in situ and in culture. Immunohistochemistry demonstrated the strongest expression of IL-27 by endothelial cells and mononuclear phagocytes. Its production by periapical lesion mononuclear cells (PL-MNC), especially in symptomatic lesions, was significantly higher compared with that in peripheral blood MNC and correlated with the frequency of CD14+ and CD3+ cells. Exogenous IL-27 stimulated Th1 and down-regulated Th17 cytokine production by PL-MNC from symptomatic lesions, but down-regulated Th1 and Th2 responses in asymptomatic lesions. These findings suggest that IL-27 is an immunomodulatory cytokine in periapical lesions, with complex biological effects. </jats:p

Characterization of antigen-presenting cells in human apical periodontitis lesions by flow cytometry and immunocytochemistry

Aim To analyse phenotypic characteristics of antigen-presenting cells (APC), isolated from human periapical lesions by flow cytometry and immunocytochemistry. Methodology Sixteen periapical lesions were digested for 15 min with 0.05% collagenase. Mononuclear cells, separated from other inflammatory cells by density centrifugation, were processed for flow cytometry and/or immunocytochemistry. Single and double immunostainings were performed using monoclonal antibodies specific for human CD45, CD3, CD19, CD14, HLA-DR, CD1a, CD83 and CD123. Results Antigen-presenting cells (HLA-DR+ cells) represented 32.9 +/- 17.8% of total mononuclear cells. Amongst them, B cells (HLA-DR+ CD19(+)) were the predominant APC population, followed by activated macrophages (HLA-DR+ CD14(+)), dendritic cells (DC) (HLA-DR+ CD14(-) CD19(-) CD3(-)) and activated T cells (HLA-DR+ CD3(+)). Based on the predominance of T cells (CD3(+)) or B cells and plasma cells (CD19(+) and CD19(lo), respectively) amongst mononuclear cell infiltrates, lesions were divided into T- and B-types. The percentage of DC in T-type lesions (27.1 +/- 6.8% of total HLA-DR+ cells) was higher, compared with B-type lesions (10.3 +/- 5.2%) (P lt 0.01). Within the DC population, the percentages of CD1a (Langerhans cell type) and CD123 (probably plasmacytoid DC type) did not differ significantly between the groups (P gt 0.05). However, the percentage of mature DC (CD83(+)) was significantly higher in T-type periapical lesions (P lt 0.05). Conclusion Flow cytometry and immunocytochemistry are suitable methods for phenotypic analysis of APC after their isolation from human periapical lesions. APC, that were phenotypically heterogeneous, constituted a significant component of infiltrating cells. Lesions with the predominance of T cells were characterized by a higher proportion of mature DC (HLA-DR(+)CD83(+) cells) than lesions with predominance of B cells/plasma cells

Regulatory T-cells in Periapical Lesions

CD4+CD25hiFoxp3+ regulatory T-cells (Tregs) are of crucial importance in regulating the immune response, including the control of any defense against infection. Their presence in periapical lesions has not been demonstrated, as yet. We hypothesized that Tregs infiltrate periapical lesions, where they inhibit T-cell proliferation. The aim of this study was to characterize Tregs in periapical lesions by confocal microscopy, flow cytometry, and functional assays. We showed that CD4+CD25hiFoxp3+ cells in periapical lesions expressed IL-10 and TGF-β. Their frequency was significantly higher than in peripheral blood and correlated with the levels of TGF-β and IL-10 in culture supernatants of periapical lesion mononuclear cells. Tregs inhibited the proliferation of responder T-cells in vitro, at least in part, by stimulating the production of IL-10. These findings suggest that CD4+CD25hiFoxp3+ cells in periapical lesions may play regulatory roles in controlling local immune/inflammatory processes. </jats:p