Cholesterol crystals in periapical lesions of root filled teeth.

AIM: To determine the prevalence of cholesterol crystals in periapical biopsies and to evaluate the correlation between cholesterol crystals in periapical biopsies and age, gender, location of the periapical lesion, pathologic diagnosis and lesion size. METHODOLOGY: The biopsy report database (Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand) during 2005-2014 was reviewed. The prevalence of cholesterol crystals in the periapical lesions of root filled teeth was determined. Pathological diagnosis, patients' age, gender and the location (maxilla or mandible) of the periapical lesion were obtained from treatment records. The area of the lesion from the periapical radiograph before surgery was calculated using ImageJ software. Univariate and multivariate logistic regression analyses were used to determine the association between independent variables and the presence of cholesterol crystals. RESULTS: The overall prevalence of cholesterol crystals was 20.31%. The periapical biopsies >100 mm2 in size on periapical films had a significantly greater prevalence of cholesterol crystals than those <100 mm2 (P = 0.005). The biopsies diagnosed as radicular cysts had a significantly greater prevalence of cholesterol crystals than the biopsies with other diagnoses (P < 0.001). A pathological diagnosis of radicular cyst was the variable with the strongest association with the presence of cholesterol crystals (P < 0.001; adjusted OR, 12.39). CONCLUSIONS: Presence of cholesterol crystals was associated with periapical lesion diagnosed as a radicular cyst and lesion >100 mm2 in area. Age, gender and location of the lesion did not influence the presence of cholesterol crystals.

Development of multiplex pyrosequencing for HLA-B*57:01 screening using single nucleotide polymorphism haplotype.

WHAT IS KNOWN AND OBJECTIVE: Abacavir (ABC) is a commonly used nucleoside reverse-transcriptase inhibitor with potent antiviral activity against HIV-1. The US Food and Drug Administration and international HIV treatment guidelines recommend HLA-B*57:01 screening before initiating treatment with ABC. The current standard method for HLA-B*57:01 screening is limited by its high-cost, time-consuming and labour-intensive procedure with the requirement of a specialized laboratory. Our study aims to develop a more reliable screening test by selecting rs3093726 as an additional single nucleotide polymorphism (SNP) to combine with rs2395029 for multiplex pyrosequencing development. It offers high-accuracy, cost-effective and rapid detection. METHODS: Multiplex pyrosequencing was developed for HLA-B*57:01 screening using rs2395029 and rs3093726 as a surrogate marker and tested in 130 Thai subjects in parallel with singleplex pyrosequencing of each SNP and the standard sequence-based method. RESULTS AND DISCUSSION: Multiplex pyrosequencing showed 100% concordance when compared with both singleplex pyrosequencing and standard sequence-based method. This method showed 100% of negative predictive value (NPV), positive predictive value (PPV), specificity and sensitivity. WHAT IS NEW AND CONCLUSION: Multiplex pyrosequencing is a powerful tool for HLA-B*57:01 screening using the rs2395029 and rs3093726 haplotype genotyping as surrogate marker for this HLA-B. The assay provides accurate, cost-effective and rapid detection of this haplotype. It can be applied for ABC hypersensitivity screening of the Thai population before initiating treatment with ABC.