1,090 research outputs found
Milieu-adopted in vitro and in vivo differentiation of mesenchymal tissues derived from different adult human CD34-negative progenitor cell clones
Adult mesenchymal stem cells with multilineage differentiation potentially exist in the bone marrow, but have also been isolated from the peripheral blood. The differentiation of stem cells after leaving their niches depends predominately on the local milieu and its new microenvironment, and is facilitated by soluble factors but also by the close cell-cell interaction in a three-dimensional tissue or organ system. We have isolated CD34-negative, mesenchymal stem cell lines from human bone marrow and peripheral blood and generated monoclonal cell populations after immortalization with the SV40 large T-antigen. The cultivation of those adult stem cell clones in an especially designed in vitro environment, including self-constructed glass capillaries with defined growth conditions, leads to the spontaneous establishment of pleomorphic three-dimensional cell aggregates ( spheroids) from the monoclonal cell population, which consist of cells with an osteoblast phenotype and areas of mineralization along with well-vascularized tissue areas. Modifications of the culture conditions favored areas of bone-like calcifications. After the transplantation of the at least partly mineralized human spheroids into different murine soft tissue sites but also a dorsal skinfold chamber, no further bone formation could be observed, but angiogenesis and neovessel formation prevailed instead, enabling the transplanted cells and cell aggregates to survive. This study provides evidence that even monoclonal adult human CD34-negative stem cells from the bone marrow as well as peripheral blood can potentially differentiate into different mesenchymal tissues depending on the local milieu and responding to the needs within the microenvironment. Copyright (C) 2005 S. Karger AG, Basel
Concurrent TNFRSF1A R92Q and pyrin E230K mutations in a child with multiple sclerosis
We report a 16-year-old female patient with a severe course of multiple sclerosis and concomitant symptoms suggestive of a hereditary autoinflammatory disease. Genetic analyses revealed that she inherited a TNFRSF1A R92Q mutation from her mother and a pyrin E230K mutation from her father. To our knowledge, this is the first report of a patient with severe childhood multiple sclerosis and mutations in two genes which predispose to hereditary autoinflammatory disorders. We speculate that these mutations contribute to early multiple sclerosis manifestation and enhance the inflammatory damage inflicted by the autoimmune response
128Xe and 130Xe: Testing He-shell burning in AGB stars
The s-process branching at 128I has been investigated on the basis of new,
precise experimental (n,g) cross sections for the s-only isotopes 128Xe and
130Xe. This branching is unique, since it is essentially determined by the
temperature- and density-sensitive stellar decay rates of 128I and only
marginally affected by the specific stellar neutron flux. For this reason it
represents an important test for He-shell burning in AGB stars. The description
of the branching by means of the complex stellar scenario reveals a significant
sensitivity to the time scales for convection during He shell flashes, thus
providing constraints for this phenomenon. The s-process ratio 128Xe/130Xe
deduced from stellar models allows for a (9+-3)% p-process contribution to
solar 128Xe, in agreement with the Xe-S component found in meteoritic presolar
SiC grains.Comment: 24 pages, 9 figures, accepted for publication in Astophysical Journa
Phase correlation of laser waves with arbitrary frequency spacing
The theoretically predicted correlation of laser phase fluctuations in
Lambda-type interaction schemes is experimentally demonstrated. We show, that
the mechanism of correlation in a Lambda scheme is restricted to high frequency
noise components, whereas in a double- scheme, due to the laser phase
locking in closed-loop interaction, it extends to all noise frequencies. In
this case the correlation is weakly sensitive to coherence losses. Thus the
double-Lambda scheme can be used to correlate e.m. fields with carrier
frequency differences beyond the GHz regime.Comment: 4 pages, 4 figure
Women’s experiences of routine care during labor and childbirth and the influence of medicalization: A qualitative study from Iran
Objective: To understand women’s experiences of routine care during labor and childbirth in a medicalized context. Design: Twenty-six in-depth interviews were conducted during the late postpartum period and thematic analysis was applied. Setting: Four public hospitals in Tehran with a high rate of births, providing services to low and middle income families. Participants: Women who had a low risk pregnancies and gave a birth to a healthy baby by normal vaginal delivery. Findings: Two main themes emerged: ‘An ethos of medicalization’ which indicates that women’s perception of childbirth was influenced by the medicalized context of childbirth. And ‘The reality of fostered medicalization’ which illustrates the process by which interventions during labor affected women’s pathway through childbirth, and how the medicalization resulted in a birth experience which often included a preference for Caesarean Section rather than vaginal delivery with multiple interventions. Implications for Practice: Contextual factors such as legal issues, state’s regulations and the organisational framework of maternity services foster medicalized childbirth in Tehran public hospitals. These factors influence the quality of care and should be considered in any intervention for change. The aim should be a high quality birth experience with minimal interventions during normal vaginal delivery. A midwifery model of care combining scientific evidence with empathy may address this need for change
Signatures of currency vertices
Many real-world networks have broad degree distributions. For some systems,
this means that the functional significance of the vertices is also broadly
distributed, in other cases the vertices are equally significant, but in
different ways. One example of the latter case is metabolic networks, where the
high-degree vertices -- the currency metabolites -- supply the molecular groups
to the low-degree metabolites, and the latter are responsible for the
higher-order biological function, of vital importance to the organism. In this
paper, we propose a generalization of currency metabolites to currency
vertices. We investigate the network structural characteristics of such
systems, both in model networks and in some empirical systems. In addition to
metabolic networks, we find that a network of music collaborations and a
network of e-mail exchange could be described by a division of the vertices
into currency vertices and others.Comment: to appear in Journal of the Physical Society of Japa
Ventral motor neuron alterations in rat spinal cord after chronic exercise
The observed differences in the soma and nuclear diameters reflect chronic changes specific to each exercise regimen used.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42652/1/18_2005_Article_BF01946563.pd
MontanAqua. Anticiper le stress hydrique dans les Alpes ? Scénarios de gestion de l'eau dans la région de Crans-Montana-Sierre (Valais) : résultats finaux et recommandations
MontanAqua. Anticiper le stress hydrique dans les Alpes ? Scénarios de gestion de l'eau dans la région de Crans-Montana-Sierre (Valais) : résultats finaux et recommandations
A Counterpart to the Radial Orbit Instability in Triaxial Stellar Systems
Self-consistent solutions for triaxial mass models are highly non-unique. In
general, some of these solutions might be dynamically unstable, making them
inappropriate as descriptions of steady-state galaxies. Here we demonstrate for
the first time the existence in triaxial galaxy models of an instability
similar to the radial-orbit instability of spherical models. The instability
manifests itself when the number of box orbits, with predominantly radially
motions, is sufficiently large. N-body simulations verify that the evolution is
due neither to chaotic orbits nor to departures of the model from
self-consistency, but rather to a collective mode. The instability transforms
the triaxial model into a more prolate, but still triaxial, configuration.
Stable triaxial models are obtained when the mass contribution of radial orbits
is reduced. The implications of our results for the shapes of dark-matter halos
are discussed.Comment: 14 pages, 16 figure
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