338 research outputs found
Localized intersection of currents and the Lefschetz coincidence point theorem
We introduce the notion of a Thom class of a current and define the localized
intersection of currents. In particular we consider the situation where we have
a smooth map of manifolds and study localized intersections of the source
manifold and currents on the target manifold. We then obtain a residue theorem
on the source manifold and give explicit formulas for the residues in some
cases. These are applied to the problem of coincidence points of two maps. We
define the global and local coincidence homology classes and indices. A
representation of the Thom class of the graph as a Cech-de~Rham cocycle
immediately gives us an explicit expression of the index at an isolated
coincidence point, which in turn gives explicit coincidence classes in some
non-isolated components. Combining these, we have a general coincidence point
theorem including the one by S. Lefschetz
Immunohistochemical Expressions of Main PGE2 Biosynthesis-related Enzymes and PGE2 Receptor in Rat Nephrogenesis
Endogenous prostaglandin (PG) E2 plays important roles in renal homeostasis.
Immunoexpressions of PGE2 biosynthesis-related enzymes, cyclooxygenase (COX)-2
and microsomal PGE2 synthetase (mPGES)-1 and EP4 (a PGE2 receptor),
were investigated in renal development. Kidney tissues were obtained from fetuses on
gestation days 18 and 21 and neonates on days 1 to 18. In fetuses and early neonates, the
expressions of COX-2, mPGES-1 and EP4 were observed in developing renal tubules,
indicating that COX-2 and its product, PGE2, play important roles in blastemal
cell-derived renal tubular development via EP4. Cyclin D1 expression was seen in both the
nucleus and cytoplasm of the developing tubules. These findings differed from the
decreased COX-2 expression and exclusive nuclear expression of cyclin D1 seen in abnormal
epithelial regeneration of injured renal tubules in cisplatin-treated rats in our previous
articles. Collectively, PGE2, induced by COX-2, regulates renal tubular
epithelial formation via EP4
Comparative Gene Expression Analysis in the Skeletal Muscles of Dysferlin-deficient SJL/J and A/J Mice
Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was conducted to
determine whether or not there are interstrain or site-dependent differences in the gene
expression profiles of skeletal muscles in SJL/J and A/J mice as dysferlinopathy models.
Upon analysis by qRT-PCR, SJL/J mice showed a trend of increased gene expression level of
uncoupling protein 2 in the rectus femoris and longissimus lumborum at 30 weeks of age
when dystrophic lesions became histopathologically pronounced. Heme oxygenase 1 and S100
calcium binding protein A4 were upregulated in the rectus femoris, longissimus lumborum
and abdominal muscles, in which dystrophic lesions occur more commonly in SJL mice. The
gene expression levels of heat shock protein 70 in most muscles of A/J mice were lower
than those of BALB/c mice as control. SJL/J mice exhibited a marked lowering of
decay-accelerating factor 1/CD55 gene expression level in all studied muscles except for
the heart at all ages compared with that of BALB/c mice. This study showed that there were
some interstrain differences in the gene expres sion profiles of skeletal muscles between
SJL/J and A/J mice. Further investigation is required to reveal whether these alterations
of the expression levels are the cause of dystrophic changes or occur subsequent to muscle
damage
Thy-1 Expressing Mesenchymal Cells in Rat Nephrogenesis in Correlation with Cells Immunoreactive for α-Smooth Muscle Actin and Vimentin
Thy-1 expression may influence myofibroblast development. Through the
epithelial-mesenchymal transition (EMT), injured renal epithelial cells undergo
regression to the metanephric mesenchymal phenotype and then acquire a
myofibroblastic nature (expressing α-smooth muscle actin; α-SMA). Because the
metanephric blastema differentiates into mesenchymal and renal epithelial cells,
we investigated Thy-1 immunoexpression during nephrogenesis in F344 rats in
correlation with vimentin and α-SMA expressions. Kidney samples were obtained
from fetuses on gestation days 18 and 21, neonates on days 1-18 and adults at 6
weeks of age. Mesangial cells in S-shaped bodies and immature and mature
glomeruli continuously expressed both Thy-1 and α-SMA during early nephrogenesis
(fetuses and neonates on days 1-9). During early nephrogenesis, loosely-arranged
blastemal cell-derived mesenchymal cells in the cortex and medulla also
exhibited Thy-1 and α-SMA, although the α-SMA expression was weaker than that of
Thy-1. Vimentin expression coincided with that of Thy-1. These findings indicate
that the derivation of α-SMA-expressing myofibroblastic cells may be related to
mesangial or blastemal cells expressing both Thy-1 and α-SMA. Interestingly,
there was a difference in Thy-1 expression between cortical and medullary
tubulointerstitial cells from late nephrogenesis (neonates on days 12-18) and
those from adults in that the cortical cells reacted faintly or negatively to
Thy-1, whereas the medullary cells reacted strongly to Thy-1; additionally,
bundle-arranged mesenchymal cells that were only observed in the neonates on
days 1-12 reacted strongly to α-SMA, but faintly to Thy-1. Blastemal
cell-derived mesenchymal cells seem to alter the immunoexpressions of Thy-1 and
α-SMA, depending on the conditions which they develop. Thy-1 immunoexpression
would be useful for investigation of reverse embryogenesis, which might occur in
fibrotic kidneys
Endurance training facilitates myoglobin desaturation during muscle contraction in rat skeletal muscle.
At onset of muscle contraction, myoglobin (Mb) immediately releases its bound O2 to the mitochondria. Accordingly, intracellular O2 tension (PmbO2) markedly declines in order to increase muscle O2 uptake (mVO2). However, whether the change in PmbO2 during muscle contraction modulates mVO2 and whether the O2 release rate from Mb increases in endurance-trained muscles remain unclear. The purpose of this study was, therefore, to determine the effect of endurance training on O2 saturation of Mb (SmbO2) and PmbO2 kinetics during muscle contraction. Male Wistar rats were subjected to a 4-week swimming training (Tr group; 6 days per week, 30 min × 4 sets per day) with a weight load of 2% body mass. After the training period, deoxygenated Mb kinetics during muscle contraction were measured using near-infrared spectroscopy under hemoglobin-free medium perfusion. In the Tr group, the VmO2peak significantly increased by 32%. Although the PmbO2 during muscle contraction did not affect the increased mVO2 in endurance-trained muscle, the O2 release rate from Mb increased because of the increased Mb concentration and faster decremental rate in SmbO2 at the maximal twitch tension. These results suggest that the Mb dynamics during muscle contraction are contributing factors to faster VO2 kinetics in endurance-trained muscle
Local Genetic Differentiation within Rebun Island in Cypripedium macranthos var. rebunense Revealed by Genome-wide SNP Analysis Using MIG-seq
Poster Presentation
Relationship of Cell Proliferating Marker Expressions with PGE2 Receptors in Regenerating Rat Renal Tubules after Cisplatin Injection
Cisplatin, an anticancer drug, is well known to have nephrotoxicity as an adverse
effect. We investigated the expressions of cell cycle markers and prostaglandin
E2 (PGE2) receptors (EP) in the affected renal tubules
in rats injected with a single dose (6 mg/kg body weight) of cisplatin. On days
1–3 after dosing, the affected renal epithelial cells were almost desquamated,
showing necrosis. On day 5 onwards, the renal tubules were rimmed by flattened
or cuboidal epithelial cells with basophilic cytoplasm; BrdU-immunopositive
cells began to significantly increase, indicating regeneration. Simultaneously,
TUNEL-positive apoptotic cells were also seen. On days 1–5, cyclin
D1-immunopositive cells were decreased with an increased expression in p21 mRNA,
indicating G1 arrest in the cell cycle. The affected renal epithelial
cells began to react to EP4 receptor, but not to EP2 receptor. Some EP4
receptor-reacting epithelial cells gave a positive reaction to BrdU or cyclin
D1. Collectively, the affected renal tubules underwent various alterations such
as necrosis, apoptosis, regeneration and G1 arrest; the aspects might
be influenced by endogenous PGE2 through EP4 receptor
A Rhabdomyosarcoma Arising in the Larynx of a Dog
A neoplastic nodular lesion, 2 × 3 cm in diameter, was found in the larynx of a
6-year-old spayed female dog. The tumor was ill-circumscribed, consisting histologically
of large round cells with abundant cytoplasm interspersed with small round cells with less
cytoplasm and occasional multinucleated cells (myotubes). Immunohistochemically, tumor
cells were positive for myoglobin, desmin and vimentin in varying degrees, but negative
for S-100 protein, GFAP or cytokeratin. Cytoplasmic myofilaments/myofibrils with a dense
Z-line-like structure were seen, the fine structures of which were complemented by PTAH
stain. Based on these findings, the tumor was diagnosed as a rhabdomyosarcoma, a very rare
tumor in the larynx of dogs
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