Ancient remains preserved in glaciers present a unique opportunity for us to advance our knowledge of human origins, diversity, and health, a central focus of anthropological studies. Cellular components of hard and soft tissue from frozen human remains dated between 1670 to 1850 cal AD recovered from a glacier in Canada were studied. Despite the expected ice crystal damage in some samples, regions of recognizable structure and ultrastructure were observed. We found that the state of preservation was tissue specific and that in some tissues the organelles were better preserved than in others. Skeletal, connective, nervous, and epithelial tissues were recognizable in some of the samples. DNA had been previously extracted from these remains and this study illustrates that the ability to successfully extract DNA may correlate with good preservation of histology.
This study applied a linear discriminant analysis model to evaluate the performance of 2 types of commercially available extractable nuclear antigen (ENA) immunoassays for the screening and diagnosis of systemic autoimmune rheumatic diseases (SARDs) in a large tertiary hospital reference laboratory: (1) an enzyme-linked immunosorbent assay (ELISA) and (2) a multiplex bead-based immunoassay (MPBI). The results of the study showed both ENA immunoassays had comparable sensitivity for the detection of SARDs compared with the antinuclear antigen immunofluorescence (ANA-IF) method (ANA-IF: 85.6%, ENA-ELISA: 91.5%, ENA-MPBI: 83.1%, pairwise comparisons with ANA-IF: P > .05). However, both ENA immunoassays offered improved specificity compared with the ANA-IF (ANA-IF: 24.2%; ENA-ELISA: 39.8%; ENA-MPBI: 53.1%; pairwise comparison with ANA-IF: P < .001). The use of a more specific screening immunoassay with comparable sensitivity to ANA-IF is important in a tertiary hospital with high prevalence of non-SARD immune diseases. Diagnostic performance of the ENA/dsDNA components by the MPBI and ELISA methods did not differ significantly (area under the curve [AUC], 81.0% vs 83.0%, respectively, P > .05), but the key ENA/dsDNA variables contributing to the discriminating power of the assays for the diagnosis of specific SARDs were reagent/method dependent.
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