86 research outputs found
Differentiation of Human Bone Marrow Mesenchymal Stem Cells to Chondrocytes for Construction of Three-dimensional Cartilage Tissue
A differentiation method of human bone marrow mesenchymal stem cells (MSCs) to chondrocytes was developed for the construction of a three-dimensional (3D) cartilage tissue. The adhesive cells, which were isolated from a human bone marrow aspirate were embedded in type I collagen in a poly-l-lactate-glycolic acid copolymer (PLGA) mesh and cultivated for 4 week together with growth factors. The degree of cellular differentiation was estimated by quantitative RT-PCR of aggrecan and type II collagen mRNAs and by staining with Safranin O. The 3D culture showed a higher degree of differentiation even without growth factors than the conventional pellet culture with growth factors, namely, dexamethasone and transforming growth factor (TGF)-β 3. The 3D culture for 2 week with the combined addition of dexamethasone, TGF-β 3, and insulin-like growth factor (IGF)-I reached a 30% expression of aggrecan mRNA compared with that in primary human chondrocytes, while the aggrecan mRNA expression in the conventional pellet culture was less than 2%. The sequential two-step differentiation cultivation, during which the cells were cultivated in 3D for 1 week after the conventional two-dimensional (2D) culture for 1 week, could markedly accelerate the expression of aggrecan mRNA compared with the 3D cultivation for 2 week
Effect of Subcultivation of Human Bone Marrow Mesenchymal Stem on their Capacities for Chondrogenesis, Supporting Hematopoiesis, and Telomea Length
Effects of subcultivation of human bone marrow mesenchymal stem cells on their capacities for chondrogenesis and supporting hematopoiesis, and telomea length were investigated. Mesenchymal stem cells were isolated from human bone marrow aspirates and subcultivated several times at 37℃ under a 5% CO2 atmosphere employing DMEM medium containing 10% FCS up to the 20th population doubling level (PDL). The ratio of CD45- CD105+ cells among these cells slightly increased as PDL increased. However, there was no marked change in the chondrogenic capacity of these cells, which was confirmed by expression assay of aggrecan mRNA and Safranin O staining after pellet cell cultivation. The change in capacity to support hematopoiesis of cord blood cells was not observed among cells with various PDLs. On the other hand, telomere length markedly decreased as PDL increased at a higher rate than that at which telomere length of primary mesenchymal stem cells decreased as the age of donor increased
MAXI and NuSTAR observations of the faint X-ray transient MAXI J1848-015 in the GLIMPSE-C01 Cluster
We present the results of MAXI monitoring and two NuSTAR observations of the
recently discovered faint X-ray transient MAXI J1848-015. Analysis of the MAXI
light-curve shows that the source underwent a rapid flux increase beginning on
2020 December 20, followed by a rapid decrease in flux after only days.
NuSTAR observations reveal that the source transitioned from a bright soft
state with unabsorbed, bolometric (- keV) flux , to a low hard state with flux . Given a distance of
kpc, inferred via association of the source with the GLIMPSE-C01 cluster,
these fluxes correspond to an Eddington fraction of order for an
accreting neutron star of mass , or even lower for a more massive
accretor. However, the source spectra exhibit strong relativistic reflection
features, indicating the presence of an accretion disk which extends close to
the accretor, for which we measure a high spin, . In addition
to a change in flux and spectral shape, we find evidence for other changes
between the soft and hard states, including moderate disk truncation with the
inner disk radius increasing from to
, narrow Fe emission whose centroid
decreases from keV to keV, and an increase in
low-frequency (- Hz) variability. Due to the high spin we
conclude that the source is likely to be a black hole rather than a neutron
star, and we discuss physical interpretations of the low apparent luminosity as
well as the narrow Fe emission.Comment: 19 pages, 9 figures, 3 tables. Accepted for publication in Ap
Dynamic carbon dioxide exchange through snowpack by wind-driven mass transfer in a conifer-broadleaf mixed forest in northernmost Japan
Effect of salt concentration on intracellular accumulation of lipids and triacylglyceride in marine microalgae Dunaliella cells.
In order to get the high liquefaction yield from marine algae cell mass to fuel oil, the effect of salt stress on the accumulation of lipids and triacylglyceride in Dunaliella cells was investigated. Although initial NaCl concentration higher than 1.5 M markedly inhibited cell growth, increase of initial NaCl concentration from 0.5 (equal to sea water) to 1.0 M resulted in a higher intracellular lipid content (67%) in comparison with 60% for the salt concentration of 0.5 M. Addition of 0.5 or 1.0 M NaCl at mid-log phase or the end of log phase during cultivation with initial NaCl concentration of 1.0 M further increased the lipid content (70%)
High inoculation cell density could accelerate the differentiation of human bone marrow mesenchymal stem cells to chondrocyte cells.
The effects of the density of human mesenchymal stem cells (MSCs) on their differentioation to chondrocytes in a differentiation medium supplemented with dexamethasone, TGFβ3, and IGF-1 were investigated for the regenerative therapy of cartilage. The increase in the initial density of MSCs from 0.05×104 to 0.9×104 cells/cm2 accelerated the increase in the expression level of aggrecan mRNA during the differentiation culture for 7 d. The conditioned medium harvested at 7 d from the differentiation culture with an initial MSC density of 0.3×104 cells/cm2 accelerated the initial increase in the expression level for 3 d in the differentiation culture with an initial MSC density of 0.3×104 cells/cm2, whereas the conditioned medium harvested at 7 d in the differentiation culture with an initial MSC density of 0.05×104 cells/cm2 did not. The differentiation culture after 14 d with an initial MSC concentration of 0.3×104 cells/cm2 showed an expression level 1.7-fold that in the case of the culture with an initial MSC concentration of 0.05×104 cells/cm2. Thus, a high MSC inoculum density might be appropriate for the rapid differentiation of MSCs to chondrocytes
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