Proposal of a new classification system for complete mesocolic excison in right-sided colon cancer.

BACKGROUND: Although complete mesocolic excision has been performed for 10 years there remains no published prospective data. The lack of a classification which includes completeness of mesocolic tissue removal as well as plane of surgery contributes to the problem of comparing studies. The aim of the present study was to develop such a classification for right hemicolectomy. METHODS: In a prospective, non-randomized trial we collected specimens of right hemicolectomies from 38 German hospitals between February 2012 and October 2016. The degree of radicality of resection was reported. Photographs were taken of the specimens. After screening the images it became apparent that the specimens could be divided into four main groups according to the degree of missing mesocolic tissue, and three subgroups reflecting the plane of surgery. RESULTS: Of 1373 patients 1097 images were available. Grading was possible in 1077 (98.2%). Distribution was Type 0 (best) 38.6%, Type I 43.3%, Type II 8.5%, Type III (poorest) 7.8%. Surgery was considered to be in a suboptimal plane of surgery in 15.2% overall, highest in Type III (37%) and lowest in Type 0 (7.8%, p < 0.001). CONCLUSIONS: The proposed classification may be a relevant tool for the further investigation of CME for right colon cancer because it allows us to differentiate the aspects of lymphadenectomy and the preservation of the integrity of the mesocolon.

Novel contribution on the diagenetic physicochemical features of bone and teeth minerals, as substrates for ancient DNA typing.

The extraction of DNA from skeletal remains is a major step in archeological or forensic contexts. However, diagenesis of mineralized tissues often compromises this task although bones and teeth may represent preservation niches allowing DNA to persist over a wide timescale. This exceptional persistence is not only explained on the basis of complex organo-mineral interactions through DNA adsorption on apatite crystals composing the mineral part of bones and teeth but is also linked to environmental factors such as low temperatures and/or a dry environment. The preservation of the apatite phase itself, as an adsorption substrate, is another crucial factor susceptible to significantly impact the retrieval of DNA. With the view to bring physicochemical evidence of the preservation or alteration of diagenetic biominerals, we developed here an analytical approach on various skeletal specimens (ranging from ancient archeological samples to recent forensic specimens), allowing us to highlight several diagenetic indices so as to better apprehend the complexity of bone diagenesis. Based on complementary techniques (X-ray diffraction (XRD), Fourier transform infrared (FTIR), calcium and phosphate titrations, SEM-EDX, and gravimetry), we have identified specific indices that allow differentiating 11 biological samples, primarily according to the crystallinity and maturation state of the apatite phase. A good correlation was found between FTIR results from the analysis of the v3(PO4) and v4(PO4) vibrational domains and XRD-based crystallinity features. A maximal amount of information has been sought from this analytical approach, by way of optimized posttreatment of the data (spectral subtraction and enhancement of curve-fitting parameters). The good overall agreement found between all techniques leads to a rather complete picture of the diagenetic changes undergone by these 11 skeletal specimens. Although the heterogeneity and scarcity of the studied samples did not allow us to seek direct correlations with DNA persistence, the physicochemical parameters described in this work permit a fine differentiation of key properties of apatite crystals among post mortem samples. As a perspective, this analytical approach could be extended to more numerous sets of specimens so as to draw statistical relationships between mineral and molecular conservation.