315 research outputs found
GATA1 (GATA binding protein 1 (globin transcription factor1))
Review on GATA1 (GATA binding protein 1 (globin transcription factor1)), with data on DNA, on the protein encoded, and where the gene is implicated
SIL (SCL/TAL1 interrupting locus)
Review on SIL (SCL/TAL1 interrupting locus), with data on DNA, on the protein encoded, and where the gene is implicated
Measurement of polarization-transfer to bound protons in carbon and its virtuality dependence
We measured the ratio of the transverse to longitudinal
components of polarization transferred from electrons to bound protons in
by the process at the
Mainz Microtron (MAMI). We observed consistent deviations from unity of this
ratio normalized to the free-proton ratio,
, for both -
and -shell knocked out protons, even though they are embedded in averaged
local densities that differ by about a factor of two. The dependence of the
double ratio on proton virtuality is similar to the one for knocked out protons
from and , suggesting a universal behavior.
It further implies no dependence on average local nuclear density
CXCR4 mediates leukemic cell migration and survival in the testicular microenvironment
The testis is the second most frequent extramedullary site of relapse in pediatric acute lymphoblastic leukemia (ALL). The mechanism for B-cell (B) ALL cell migration towards and survival within the testis remains elusive. Here, we identified CXCL12-CXCR4 as the leading signaling axis for B-ALL cell migration and survival in the testicular leukemic niche. We combined analysis of primary human ALL with a novel patient-derived xenograft (PDX)-ALL mouse model with testicular involvement. Prerequisites for leukemic cell infiltration in the testis were pre-pubertal age of the recipient mice, high surface expression of CXCR4 on PDX-ALL cells, and CXCL12 secretion from the testicular stroma. Analysis of primary pediatric patient samples revealed that CXCR4 was the only chemokine receptor being robustly expressed on B-ALL cells both at the time of diagnosis and relapse. In affected patient testes, leukemic cells localized within the interstitial space in close proximity to testicular macrophages. Mouse macrophages isolated from affected testes, in the PDX model, revealed a macrophage polarization towards a M2-like phenotype in the presence of ALL cells. Therapeutically, blockade of CXCR4-mediated functions using an anti-CXCR4 antibody treatment completely abolished testicular infiltration of PDX-ALL cells and strongly impaired the overall development of leukemia. Collectively, we identified a pre-pubertal condition together with high CXCR4 expression as factors affecting the leukemia permissive testicular microenvironment. We propose CXCR4 as a promising target for therapeutic prevention of testicular relapses in childhood B-ALL
Quasi-elastic polarization-transfer measurements on the deuteron in anti-parallel kinematics
We present measurements of the polarization-transfer components in the
H reaction, covering a previously unexplored kinematic
region with large positive (anti-parallel) missing momentum, , up
to 220 MeV, and . These measurements, performed
at the Mainz Microtron (MAMI), were motivated by theoretical calculations which
predict small final-state interaction (FSI) effects in these kinematics, making
them favorable for searching for medium modifications of bound nucleons in
nuclei. We find in this kinematic region that the measured
polarization-transfer components and and their ratio agree with the
theoretical calculations, which use free-proton form factors. Using this, we
establish upper limits on possible medium effects that modify the bound
proton's form factor ratio at the level of a few percent. We also
compare the measured polarization-transfer components and their ratio for H
to those of a free (moving) proton. We find that the universal behavior of
H, He and C in the double ratio
is maintained in the positive
missing-momentum region
Comparison of recoil polarization in the process for protons extracted from and shell
We present first measurements of the double ratio of the polarization
transfer components for knock-out protons from and
shells in measured by the reaction in quasi-elastic kinematics. The data are
compared to theoretical predictions in relativistic distorted-wave impulse
approximation. Our results show that differences between - and -shell
protons, observed when compared at the same initial momentum (missing momentum)
largely disappear when the comparison is done at the same proton virtuality. We
observe no density-dependent medium modifications for protons from and
shells with the same virtuality in spite of the large differences in the
respective nuclear densities
Components of polarization-transfer to a bound proton in a deuteron measured by quasi-elastic electron scattering
We report the first measurements of the transverse ( and ) and
longitudinal () components of the polarization transfer to a bound
proton in the deuteron via the reaction,
over a wide range of missing momentum. A precise determination of the electron
beam polarization reduces the systematic uncertainties on the individual
components, to a level that enables a detailed comparison to a state-of-the-art
calculation of the deuteron that uses free-proton electromagnetic form factors.
We observe very good agreement between the measured and the calculated
ratios, but deviations of the individual components. Our results
cannot be explained by medium modified electromagnetic form factors. They point
to an incomplete description of the nuclear reaction mechanism in the
calculation
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