852 research outputs found
Current-Induced Resonant Motion of a Magnetic Vortex Core: Effect of Nonadiabatic Spin Torque
The current-induced resonant excitation of a magnetic vortex core is
investigated by means of analytical and micromagnetic calculations. We find
that the radius and the phase shift of the resonant motion are not correctly
described by the analytical equations because of the dynamic distortion of a
vortex core. In contrast, the initial tilting angle of a vortex core is free
from the distortion and determined by the nonadiabaticity of the spin torque.
It is insensitive to experimentally uncontrollable current-induced in-plane
Oersted field. We propose that a time-resolved imaging of the very initial
trajectory of a core is essential to experimentally estimate the
nonadiabaticity.Comment: 4 pages, 4 figure
Growth differentiation factor 11 locally controls anterior-posterior patterning of the axial skeleton.
Growth and differentiation factor 11 (GDF11) is a transforming growth factor β family member that has been identified as the central player of anterior-posterior (A-P) axial skeletal patterning. Mice homozygous for Gdf11 deletion exhibit severe anterior homeotic transformations of the vertebrae and craniofacial defects. During early embryogenesis, Gdf11 is expressed predominantly in the primitive streak and tail bud regions, where new mesodermal cells arise. On the basis of this expression pattern of Gdf11 and the phenotype of Gdf11 mutant mice, it has been suggested that GDF11 acts to specify positional identity along the A-P axis either by local changes in levels of signaling as development proceeds or by acting as a morphogen. To further investigate the mechanism of action of GDF11 in the vertebral specification, we used a Cdx2-Cre transgene to generate mosaic mice in which Gdf11 expression is removed in posterior regions including the tail bud, but not in anterior regions. The skeletal analysis revealed that these mosaic mice display patterning defects limited to posterior regions where Gdf11 expression is deficient, whereas displaying normal skeletal phenotype in anterior regions where Gdf11 is normally expressed. Specifically, the mosaic mice exhibited seven true ribs, a pattern observed in wild-type (wt) mice (vs. 10 true ribs in Gdf11-/- mice), in the anterior axis and nine lumbar vertebrae, a pattern observed in Gdf11 null mice (vs. six lumbar vertebrae in wt mice), in the posterior axis. Our findings suggest that GDF11, rather than globally acting as a morphogen secreted from the tail bud, locally regulates axial vertebral patterning
The effect of palonosetron on rocuronium-induced withdrawal movement
AbstractBackgroundRocuronium causes pain and withdrawal movement during induction of anesthesia. In this study, palonosetron was investigated to have analgesic effect on the reduction of rocuronium-induced withdrawal movement.Methods120 patients were randomly assigned to one of three groups to receive either saline, lidocaine 20mg, or palonosetron 0.075mg with a tourniquet applied two minutes before thiopental sodium (5mg·kg−1) was given intravenously. After loss of consciousness, rocuronium (0.6mg·kg−1) was injected and the withdrawal movement was estimated by 4-point scale in a double-blind manner.ResultsThe overall incidence of rocuronium withdrawal movement was 50% with lidocaine (p=0.038), 38% with palonosetron (p=0.006) compared with 75% for saline. The incidence of no pain to mild pain was significantly lower in the lidocaine and palonosetron groups (85% and 92% respectively) than in the saline group (58%). However, there was no significant difference in withdrawal movement between the lidocaine and palonosetron groups. There was no severe movement with palonosetron.ConclusionPretreatment of palonosetron with venous occlusion may attenuate rocuronium-induced withdrawal movement as effective as the use of lidocaine. It suggested that peripheral action of palonosetron was effective to reduce rocuronium-induced withdrawal movement
The Expression of Matrix Metalloprotease 20 is Stimulated by Wild Type but not by 4 bp- or 2 bp- Deletion Mutant DLX3
Mutations in DLX3 are associated with both autosomal
dominant hypoplastic hypomaturation amelogenesis
imperfecta (ADHHAI) and tricho-dento-osseous (TDO)
syndrome. ADHHAI is caused by a c.561_562delCT (2bpdel
DLX3) mutation whereas TDO syndrome is associated
with a c.571_574delGGGG (4bp-del DLX3) mutation.
However, although the causal relationships between DLX3
and an enamel phenotype have been established, the
pathophysiological role of DLX3 mutations in enamel
development has not yet been clarified. In our current study,
we prepared expression vectors for wild type and deletion
mutant DLX3 products (4bp-del DLX3, 2bp-del DLX3) and
examined the effects of their overexpression on the
expression of the enamel matrix proteins and proteases.
Wild type DLX3 enhanced the expression of matrix
metalloprotease 20 (MMP20) mRNA and protein in murine
ameloblast-like cells. However, neither a 4bp-del nor 2bpdel
DLX3 increased MMP20 expression. Wild type DLX3,
but not the above DLX3 mutants, also increased the activity
of reporters containing 1.5 kb or 0.5 kb of the MMP20
promoter. An examination of protein stability showed that
the half-life of wild type DLX3 protein was less than 12 h
whilst that of both deletion mutants was longer than 24 h.
Endogenous Dlx3 was also found to be continuously
expressed during ameloblast differentiation. Since
inactivating mutations in the gene encoding MMP20 are
associated with amelogenesis imperfecta, the inability of
4bp-del or 2bp-del DLX3 to induce MMP20 expression
suggests a possible involvement of such mutations in the enamel phenotype associated with TDO syndrome or
ADHHAI
Phylogenetic analysis and characterization of Korean orf virus from dairy goats: case report
An outbreak of orf virus infection in dairy goats in Korea was investigated. Suspected samples of the skin and lip of affected goats were sent to the laboratory for more exact diagnosis. Orf virus was detected by electron microscopy and viral DNA was identified by PCR. To reveal the genetic characteristics of the Korean strain (ORF/09/Korea), the sequences of the major envelope protein (B2L) and orf virus interferon resistance (VIR) genes were determined and then compared with published reference sequences. Phylogenetic analysis revealed that the ORF/09/Korea strain was closest to the isolates (Taiping) from Taiwan. This is believed to be the first report on the molecular characterization of orf virus in Korea
Function of COP9 Signalosome in Regulation of Mouse Oocytes Meiosis by Regulating MPF Activity and Securing Degradation
The COP9 (constitutive photomorphogenic) signalosome (CSN), composed of eight subunits, is a highly conserved protein complex that regulates processes such as cell cycle progression and kinase signalling. Previously, we found the expression of the COP9 constitutive photomorphogenic homolog subunit 3 (CSN3) and subunit 5 (CSN5) changes as oocytes mature for the first time, and there is no report regarding roles of COP9 in the mammalian oocytes. Therefore, in the present study, we examined the effects of RNA interference (RNAi)-mediated transient knockdown of each subunit on the meiotic cell cycle in mice oocytes. Following knockdown of either CSN3 or CSN5, oocytes failed to complete meiosis I. These arrested oocytes exhibited a disrupted meiotic spindle and misarranged chromosomes. Moreover, down-regulation of each subunit disrupted the activity of maturation-promoting factor (MPF) and concurrently reduced degradation of the anaphase-promoting complex/cyclosome (APC/C) substrates Cyclin B1 and Securin. Our data suggest that the CSN3 and CSN5 are involved in oocyte meiosis by regulating degradation of Cyclin B1 and Securin via APC/C
High Extracellular Calcium Increased Expression of Ank, PC-1 andOsteopontin in Mouse Calvarial Cells
In the process of bone remodeling, mineral phase of bone
is dissolved by osteoclasts, resulting in elevation of calcium
concentration in micro-environment. This study was performed
to explore the effect of high extracellular calcium
(Ca
2+
e) on mineralized nodule formation and on the expression
of progressive ankylosis (Ank), plasma cell membrane
glycoprotein-1 (PC-1) and osteopontin by primary cultured
mouse calvarial cells. Osteoblastic differentiation and mineralized
nodule formation was induced by culture of mouse
calvarial cells in osteoblast differentiation medium containing
ascorbic acid and β-glycerophosphate. Although Ank, PC-1
and osteopontin are well known inhibitors of mineralization,
expression of these genes were induced at the later stage of
osteoblast differentiation during when expression of osteocalcin,
a late marker gene of osteoblast differentiation, was
induced and mineralization was actively progressing. High
Ca
2+
e (10 mM) treatment highly enhanced mRNA expression
of Ank, PC-1 and osteopontin in the late stage of osteoblast
differentiation but not in the early stage. Inhibition of p44/42
MAPK activation but not that of protein kinase C suppressed
high Ca
2+
e-induced expression of Ank, PC-1 and
osteopontin. When high Ca
2+
e (5 mM or 10 mM) was present
in culture medium during when mineral deposition was
actively progressing, matrix calcifiation was significantly
increased by high Ca
2+
e. This stimulatory effect was abolished
by pyrophosphate (5 mM) or levamisole (0.1-0.5 mM), an
alkaline phosphatase inhibitor. In addition, probenecid (2mM),
an inhibitor of Ank, suppressed matrix calcification in both
control and high Ca
2+
e-treated group, suggesting the possible
role of Ank in matrix calcification by osteoblasts. Taken
together, these results showed that high Ca
2+
e stimulates expression of Ank, PC-1 and osteopontin as well as matrix
calcification in late differentiation stage of osteoblasts and
that p44/42 MAPK activation is involved in high Ca
2+
e-
induced expression of Ank, PC-1 and osteopontin
- …