Apical periodontitis caused by root canal infection is the most frequent pathological lesion in the jaws, mainly manifested as periapical granulomas and cysts. Understanding of the formation and progression of apical periodontitis as well as the identification of inflammatory biomarkers can help increase the knowledge of pathogenic mechanisms, improve the diagnosis and provide support for different therapeutic strategies. The objective of the present article is to review inflammatory biomarkers such as cytokines, chemokines, inflammatory cells, neuropeptides, RANK/RANKL/OPG system and other inflammatory markers and to relate these systems to the development and progression of pathological conditions related to apical periodontitis.

INE R. SULZER, C. A. SANTA ROSA, AND MICHAEL J. FIELDS. Application of a microtechnique to the agglutination test for leptospiral antibodies. Appl. Microbiol. 13:81-85. 1965.-A microtechnique has been developed and adapted successfully to the microscopic agglutination test with live antigens for detection of leptospiral antibodies. Simultaneous titrations were performed by the conventional microscopic agglutination test and the microtechnique. When the microtechnique was used to screen 50 unknown leptospiral strains with a battery of hyperimmune sera, 98% agreement was obtained with the conventional procedure. Conmparative data on 635 tests on these 50 cultures established the reliability of the microtechnique. Results with the two tests on 46 human sera revealed 93% agreement in the detection of leptospiral antibodies. The validity and reliability of the microtechnique obtained in these comparative studies suggests that it can be used as a valuable screening procedure for the microscopic agglutination test for preliminary cross agglutination studies on unknown strains and for the detection of leptospiral antibodies in human and animal sera.

Asymptomatic Apical Periodontitis is essentially an inflammatory disease of microbial aetiology. Association and function of the cell components involved, or specific inductive factors and growth mediators associated with development, maintenance and resolution of the periapical lesions are still unknown. The objective of this study was to evaluate the concentration of Regulatory T cells (FoxP3+; Treg), Langerhans cells (CD1a+; LC) and mast cells in asymptomatic apical periodontitis. 73 cases were selected: 30 periapical granulomas, 29 radicular cysts and 14 residual cysts. All groups were submitted to morphological analysis for classification of inflammatory infiltrate and thickness of the epithelial lining as well as to immunohistochemical analysis for detection of LC and Treg cells. Toluidine blue staining was used for detecting mast cells. Analysis showed higher mean numbers of LC (8.2 cells/0.2mm 2), and Treg cells in radicular cysts (5.910 cells/0.2mm 2). As for mast cells, it was found that radicular cysts had a higher mean number of these cells compared to other periapical lesions (12.68 cells/0.2mm 2). The association between thickness of the epithelial lining and inflammatory cells showed that the presence of hypertrophic epithelium in radicular cysts presented higher density of LC. The number of LC and Treg cells play an important role in the control of the inflammatory micro-environment in periapical granulomas and radicular cysts, respectively. The presence of mast cells in radicular cysts may be associated with progression of the lesion. Knowledge regarding the inflammatory cell profile is therefore essential for a better understanding of the pathogenesis of asymptomatic periapical periodontitis.

Objective This study aimed to investigate the use of texture analysis for characterization of radicular cysts and periapical granulomas and to assess its efficacy to differentiate between both lesions with histological diagnosis. Methods Cone beam computed tomography (CBCT) images were obtained from 19 patients with 25 periapical lesions (14 radicular cysts and 11 periapical granulomas) confirmed by biopsy. Regions of interest were created in the lesions from which 11 texture parameters were calculated. Spearman's correlation analysis was performed and adjusted with Benjamini-Hochberg false discovery rate procedure (FDR <0.005). Results The texture parameters used to differentiate the lesions were assessed by using a receiver operating characteristic analysis. Five texture parameters were predictive of lesion differentiation for eight positions: angular second moment; sum of squares; sum of average; contrast; correlation. Conclusion Texture analysis of CBCT scans distinguishes radicular cysts from periapical granulomas and can be a promising diagnostic tool for periapical lesions. Clinical significance Texture analysis can be used in diagnostic and treatment monitoring to provide supplementary information.

A microtechnique has been developed and adapted successfully to the microscopic agglutination test with live antigens for detection of leptospiral antibodies. Simultaneous titrations were performed by the conventional microscopic agglutination test and the microtechnique. When the microtechnique was used to screen 50 unknown leptospiral strains with a battery of hyperimmune sera, 98% agreement was obtained with the conventional procedure. Comparative data on 635 tests on these 50 cultures established the reliability of the microtechnique. Results with the two tests on 46 human sera revealed 93% agreement in the detection of leptospiral antibodies. The validity and reliability of the microtechnique obtained in these comparative studies suggests that it can be used as a valuable screening procedure for the microscopic agglutination test for preliminary cross agglutination studies on unknown strains and for the detection of leptospiral antibodies in human and animal sera.