The potential of X-ray computed tomography for xylological and dendrochronological analyses of Egyptian mummy labels.

X-ray computed tomography (XRCT) imaging allows non-destructive visualization of the structure of various materials. Applied to wooden objects, it allows determination of their morphologies or manufacturing techniques, but also measurement of growth ring widths. We have applied XRCT to a selection of 38 mummy labels. This funerary furniture, made up of endemic or imported tree species, has survived thanks to environmental conditions in very large quantities in regions in Middle and Upper Egypt and is featured now in museum collections across the globe. Mummy labels thus represent a unique and abundant data source to build floating or absolutely dated dendrochronological chronologies for this period. Here we discuss the possible contributions and limitations of XRCT for the analysis of these artifacts and show that the approach allows identification of discriminating markers for the identification of certain species on the transverse plane, but that the insufficient resolution of the tangential and radial planes normally prevents formal identification of species. By contrast, XRCT undeniably enhances the visibility of toolmarks (in terms of numbers and depth), and thereby allows highlighting marks that remain invisible to the naked eye; XRCT also provides key insights into cutting methods and the calibers used and yields new information on silvicultural practices and the knowhow of Egyptian craftsmen. Finally, the measurement of ring widths on XRCT imagery is also more accurate than what can be achieved by traditional dendrochronological measurements, especially in the case of cuts realized on a slab. The approach also confirms the limited potential of local broadleaved species for dendrochronological approaches due to unreadable or poorly visible tree rings and mostly short tree-ring sequences.

Quantification of cytomegalovirus DNA levels in intestinal biopsies as a diagnostic tool for CMV intestinal disease.

BACKGROUND: CMV intestinal disease (CMV-ID) is a serious complication in immunocompromised patients and mainly diagnosed by clinical, endoscopic and histopathologic findings, whereas qualitative CMV-PCR in tissue samples is not recommended for diagnosis due to its low positive predictive value (PPV). OBJECTIVES: To study the interpretation and diagnostic use of CMV-quantification by PCR in intestinal tissue biopsies to recognize CMV-ID. To develop cut-off intestinal CMV-loads attributing illness to CMV. STUDY DESIGN: CMV-genome copies in 163 biopsies from the lower intestinal tract of immunocompromised patients were determined by quantitative real-time PCR, normalized to the cell number, and retrospectively compared to histopathological analysis, clinical findings and occurrence of CMV-antigenemia. Two cut-off intestinal CMV-loads, cut-off(histo) and cut-off(clin), were defined using histopathological or clinical criteria as gold standard, respectively. RESULTS: CMV was detected in 32.5% of biopsies with a more than six log range of CMV-concentrations (1 x 10(-4)-1.4 x 10(2)copies/cell). Notably, biopsies with histopathologically or clinically confirmed CMV-ID had a significantly higher CMV-load (p<0.001). Cut-off(histo) and cut-off(clin) were defined at the intestinal CMV-load of 0.14 and 0.01 copies/cell, respectively, and improved the PPV. However, cut-off(histo) showed a decreased sensitivity for clinically defined CMV-ID cases. Interestingly, many patients with CMV-ID showed no concomitant CMV-antigenemia, suggesting a localized intestinal CMV-replication. CONCLUSIONS: Quantification of CMV in intestinal biopsies is a useful diagnostic tool allowing the definition of cut-off values that can predict CMV-ID more accurate than qualitative PCR results. Further prospective studies have to clarify wether these cut-offs can improve diagnostics and treatment of CMV-ID in day-to-day clinical practice.

Cutting edge: IL-23 cross-regulates IL-12 production in T cell-dependent experimental colitis.

Although IL-12 and IL-23 share the common p40 subunit, IL-23, rather than IL-12, seems to drive the pathogenesis of experimental autoimmune encephalomyelitis and arthritis, because IL-23/p19 knockout mice are protected from disease. In contrast, we describe in this study that newly created LacZ knockin mice deficient for IL-23 p19 were highly susceptible for the development of experimental T cell-mediated TNBS colitis and showed even more severe colitis than wild-type mice by endoscopic and histologic criteria. Subsequent studies revealed that dendritic cells from p19-deficient mice produce elevated levels of IL-12, and that IL-23 down-regulates IL-12 expression upon TLR ligation. Finally, in vivo blockade of IL-12 p40 in IL-23-deficient mice rescued mice from lethal colitis. Taken together, our data identify cross-regulation of IL-12 expression by IL-23 as novel key regulatory pathway during initiation of T cell dependent colitis.