Crystallization of β-MnO 2 Nanowires in the Pores of SBA-15 Silicas: In Situ Investigation Using Synchrotron Radiation

International audienceAn original preparation method, called “two solvents” method, allows the production ofMnO2 nanowires patterned by SBA-15 silicas under mild conditions, with a preserved twodimensionalhexagonal structure, a 97% filling of the porosity by oxide nanowires, and acontrolled microstructure. A comparison is made with Mn-loaded SBA-15 prepared by moreconventional adsorption methods. In the latter case, MnOx particles inside and outside thesilica grains, empty and filled mesopores, and several Mn oxides (MnO2, Mn2O3, and Mn3O4)were identified. Once the preparation method of Mn-loaded SBA-15 optimized, various X-rayscattering and adsorption techniques using synchrotron radiation were used to observe salientfeatures of the MnO2 nanowires crystallization in situ upon calcination. X-ray absorption atthe Mn K edge shows that the oxidation state of manganese increases from (II) to (IV)between 80 and 120 °C. The oxidation of the Mn(II) salt occurs at a temperature lower thanthat necessary for bulk manganese nitrate (200 °C), which confirms its confinement withinthe SBA-15 pores. â-MnO2 nanowires of defective pyrolusite type are identified by wideanglediffraction. The comparison between diffraction results and simulations demonstratesthat the nanowire diameter is similar to the mesopore diameter of the silica host. A smallcontraction of unit-cell parameters occurs upon the crystallization of â-MnO2 nanowires. Aparallel overall intensity increase observed in small-angle X-ray diffraction is the fingerprintof a homogeneously filled porosity

Enterocytic Differentiation of cultured human colon cancer cells by replacement of glucose by galactose in the medium

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Enterocyte-like differentiation and polarization of the human colon carcinoma cell line Caco-2 in culture

International audienceThe buman colon carcinoma cell line Caco-2 grown in vitro under standard culture conditions in the absence of inducers of differentiation spontaneously exbibits signs of structural and functional differentiation and polarization. The differentiation is total at late confluency. Transmission and scanning electron microscopy show that the entire upper side of the monolayer is covered with typical brusb border microvilli which extend perpendicularly to the surface. The asymmetry of the cells and the presence of tight junctions suggest that the monolayer is polarized. Functionally the differentiation is characterized by high levels of activity of the brush border associated enzymes. The levels of alkaline phospbatase and sucrase·isomaltase are nearly 50% of those found in similar preparations of human small intestine, and 10% in the case of aminopeptidase. The presence of the enzymes is further confirmed by the immunofluorescence staining of the cells with anti-sucrase-isomaltase antibodies. The functional enterocytic differentiation of the brush border microvilli is associated with the formation of domes which are typical of transporting epithelial monolaycrs. ln the early proliferation phase of the culture 70% of the cells are structurally differentiated, but only a few of them are immunoreactive with anti-sucrase· isomaltase antibodies, and the enzyme activities are low

CDKN2A homozygous deletion is a strong adverse prognosis factor in diffuse malignant IDH-mutant gliomas

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Specific and Sensitive Diagnosis of BCOR-ITD in Various Cancers by Digital PCR

International audienceBCOR is an epigenetic regulator altered by various mechanisms including BCOR -internal tandem duplication ( BCOR -ITD) in a wide range of cancers. Six different BCOR -ITD in the 3’-part of the coding sequence of exon 15 have been reported ranging from 89 to 114 bp in length. BCOR -ITD is a common genetic alteration found in clear cell sarcoma of the kidney and primitive myxoid mesenchymal tumor of infancy (PMMTI) and it characterizes a new type of central nervous system tumor: “CNS tumor with BCOR -ITD”. It can also be detected in undifferentiated round cell sarcoma (URCS) and in high-grade endometrial stromal sarcoma (HGESS). Therefore, it is of utmost importance to search for this genetic alteration in these cancers with the most frequent technique being RNA-sequencing. Here, we developed a new droplet PCR assay (dPCR) to detect the six sequences characterizing BCOR -ITD. To achieve this goal, we used a single colored probe to detect both the duplicated region and the normal sequence that acts as a reference. We first generated seven synthetic DNA sequences: ITD0 (the normal sequence) and ITD1 to ITD6 (the duplicated sequences described in the literature) and then we set up the optima dPCR conditions. We validated our assay on 19 samples from a representative panel of human tumors (9 HGNET-BCOR, 5 URCS, 3 HGESS, and 2 PMMTI) in which BCOR -ITD status was known using at least one other method including RNA sequencing, RT-PCR or DNA-methylation profiling for CNS tumors. Our results showed that our technique was 100% sensitive and specific. DPCR detected BCOR -ITD in 13/19 of the cases; in the remaining 6 cases additional RNA-sequencing revealed BCOR gene fusions. To conclude, in the era of histomolecular classification of human tumors, our modified dPCR assay is of particular interest to detect BCOR -ITD since it is a robust and less expensive test that can be applied to a broad spectrum of cancers that share this alteration