Petrophysical zoning elements of Chertovo Koryto gold-ore deposit (Patom Upland, Eastern Siberia)

The paper considers magnetic susceptibility (chi) and electrode potentials (EP) of rocks in the Chertovo Koryto deposit. Carbon-bearing substance is found in all the studied samples, but in some cases, this substance supplies EP (-150 ± -400 mV). In these samples [chi] rarely exceeds 40·10{-5} SI units, while, in other samples [chi] is 8-10 (up to 30) times higher. Less intensive EP (-20 ± -240 mV) is furnished due to the sulfides in this deposit. Rocks with polarized carbon-bearing substance do not contain magnetic pyrrhotine and are negative linear EP anomalies. Rocks in which carbon-bearing substance is associated with pyrrhotine are revealed as magnetic anomalies. The adjacent rocks determine petrophysical zoning of the Chertovo Koryto deposit. The combination of negative linear EP anomalies and magnetic anomalies is a potential indicator and can define the multi-stage formation of the deposit itself

Activated fibronectin-secretory phenotype of mesenchymal stromal cells in pre-fibrotic myeloproliferative neoplasms

We characterized bone marrow stromal cells (BMSC) from patients with pre-fibrotic myeloproliferative neoplasms (MPN). MPN-BMSC showed decreased capacity to stimulate the proliferation of colony-forming units of normal hematopoietic stem and progenitor cells and displayed increased matrix remodelling (in particular fibronectin deposition) compared to control BMSC. This finding was confirmed in pre-fibrotic MPN bone marrow biopsies in a tissue microarray (n = 34), which stained positive for fibronectin in the absence of reticulin as a standard myelofibrosis marker. Fibronectin expression correlated significantly with reduced haemoglobin levels in MPN-patients (p = 0.007; R2 = 0.42). Our data show significant cell-intrinsic alterations in MPN-MSC and suggest that Fibronectin expression might be applicable as a biomarker for the identification of early myelofibrotic transformation in reticulin-negative MPN

Die Bedeutung der Stammzellnische bei myeloproliferativen Erkrankungen

The bone marrow microenvironment plays an essential role in regulating hematopoesis and and any disturbance in the stem cell niche seems to be of particular importance in the pathogenesis of hematological disease. This study analyzed the interaction of mesenchymal stromal cells –a main component of the hematopoietic niche- and hematopoietic stem and progenitor cells (i) in a collagen-based culture system in vitro and (ii) in vivo in an extramedullary niche by subcutaneous transplantation of the collagenous matrix in combination with beta-tri-calciumphosphate-scaffolds with defined pore sizes. In addition, the in vitro system was applied to evaluate the role of mesenchymal stromal cells in the extensive matrixremodelling in the context of myelofibrosis in patients with myeloproliferative neoplasms (MPN). The collagen-based co-culture system for mesenchymal stromal cells and hematopoietic stem and progenitor cells resembled the extracellular matrix (ECM)-based microenvironment of the bone marrow by expression of the essential matrix proteins collagen I, fibronectin and osteopontin and supported the maintenance of primitive CD34+ CD38- hematopoietic stem and progenitor cells as well as their myeloid differentiation. Stromal cells from MPN-patients showed increased production of extracellular matrix proteins, e.g. fibronectin, and induced significant contraction of the collagengels, indicating excessive matrix remodelling. Bone marrow biopsies from correlating MPN-patients confirmed increased fibronectin expression in the hematopoetic marrow, even in the absence of myelofibrosis (reticulin fibrosis). The atypical fibronectin deposits were found in close association to pathognomonic dysplastic megakaryocytes and CD271+ mesenchymal stromal cells even stained double-positive for fibronectin. This observation leads to the conclusion that, mesenchymal stromal cells actively participate in excessive matrixremodelling in the contrext of myelofibrosis in MPN-patients. To elucidate the relevance of alterations in the bone marrow microenvironment in the complex in vivo situation, beta-tri-calciumphosphate scaffolds in combination with a collagen-based matrix were transplanted subcutaneously in C57BL/6 mice -in terms of an ectopic bone marrow niche. After explantation, scaffolds revealed extramedullary hematopoiesis with myeloid and erythroid progenitors by flow cytometry and histological analysis. Therefore, the ectopic bone marrow system represents an optimal platform for dissecting hematopoietic-mesenchymal interactions