148 research outputs found
Endoscopic Mucosal Resection of Primary Anorectal Malignant Melanoma:A Case Report
Anorectal melanoma is a rare malignant tumor with a poor prognosis. However, several studies have reported cases of long-term survival. In this report, we present a patient with anorectal melanoma who has survived for 9 years after endoscopic mucosal resection. An 85-year-old man was referred to our hospital for further examination and treatment of an anal tumor 2cm in size. Endoscopic ultrasonography
revealed that the depth of tumor invasion was confined to the submucosal layer. Endoscopic mucosal resection was performed, and the tumor was diagnosed as a malignant melanoma. The patient was followed without any additional treatment, which was per his wishes. Although melanoma recurred 4 times thereafter, endoscopic mucosal resection was performed for each recurrent lesion. Thus, he has been alive for 9 years since the first endoscopic mucosal resection without distant metastases.
If the depth of tumor invasion is shallow, endoscopic mucosal resection is a useful option among other therapeutic modalities.</p
Isolation and characterization of a virus (CvV-BW1) that infects symbiotic algae of Paramecium bursaria in Lake Biwa, Japan
<p>Abstract</p> <p>Background</p> <p>We performed an environmental study of viruses infecting the symbiotic single-celled algae of <it>Paramecium bursaria </it>(<it>Paramecium bursaria Chlorella </it>virus, PBCV) in Lake Biwa, the largest lake in Japan. The viruses detected were all <it>Chlorella variabilis </it>virus (CvV = NC64A virus). One of them, designated CvV-BW1, was subjected to further characterization.</p> <p>Results</p> <p>CvV-BW1 formed small plaques and had a linear DNA genome of 370 kb, as judged by pulsed-field gel electrophoresis. Restriction analysis indicated that CvV-BW1 DNA belongs to group H, one of the most resistant groups among CvV DNAs. Based on a phylogenetic tree constructed using the <it>dnapol </it>gene, CvV was classified into two clades, A and B. CvV-BW1 belonged to clade B, in contrast to all previously identified virus strains of group H that belonged to clade A.</p> <p>Conclusions</p> <p>We conclude that CvV-BW1 composes a distinct species within <it>C. variabilis </it>virus.</p
Effect of magnetocrystalline anisotropy on magnetocaloric properties of AlFeB compound
It is well known that the temperature dependence of the effective
magnetocrystalline anisotropy energy obeys the power law of
magnetization in the Callen-Callen theory. Therefore, according to the
Callen-Callen theory, the magnetocrystalline anisotropy energy is assumed to be
zero at the critical temperature where the magnetization is approximately zero.
This study estimates the temperature dependence of the magnetocrystalline
anisotropy energy by integrating the magnetization versus magnetic field
(--) curves, and found that the magnetocrystalline anisotropy is still
finite even above the Curie temperature in the uniaxial anisotropy, whereas
this does not appear in the cubic anisotropy case. The origin is the fast
reduction of the anisotropy field, which is the magnetic field required to
saturate the magnetization along the hard axis, in the case of cubic
anisotropy. Therefore, the magnetization anisotropy and anisotropic magnetic
susceptibility, those are the key factors of magnetic anisotropy, could not be
established in the case of cubic anisotropy. In addition, the effect of
magnetocrystalline anisotropy on magnetocaloric properties, as the difference
between the entropy change curves of AlFeB appears above the Curie
temperature, which is in good agreement with a previous experimental study.
This is proof of magnetic anisotropy at slightly above Curie temperature
pH-dependent Formation of Membranous Cytoplasmic Body-like Structure of Ganglioside GM1/Bis(Monoacylglycero)Phosphate Mixed Membranes
Membrane structures of the mixtures of ganglioside GM1 and endosome specific lipid, bis(monoacylglycero)phosphate (BMP, also known as lysobisphosphatidic acid, LBPA) were examined at various pH conditions by freeze-fracture electron microscopy and small-angle x-ray scattering (SAXS). At pH 8.5 – 6.5, a GM1/BMP (1/1 mol/mol) mixture formed small vesicular aggregates, whereas the mixture formed closely packed lamellar structures under acidic conditions (pH 5.5, 4.6) with the lamellar repeat distance of 8.06 nm. Since BMP alone exhibits a diffuse lamellar structure at a broad range of pH values and GM1 forms a micelle, the present results indicate that both GM1 and BMP are required to produce the closely stacked multilamellar vesicles. These vesicles resemble membranous cytoplasmic bodies (MCB) in cells derived from patients suffering from GM1 gangliosidosis. Similar to GM1 gangliosidosis, cholesterol was trapped in BMP vesicles in GM1- and in a low pH-dependent manner. Studies employing different gangliosides and a GM1 analog suggest the importance of sugar chains and a sialic acid of GM1 in the pH-dependent structural change of GM1/BMP membranes
Binary Formation with Different Metallicities: Dependence on Initial Conditions
The fragmentation process in collapsing clouds with various metallicities is
studied using three-dimensional nested-grid hydrodynamics. Initial clouds are
specified by three parameters: cloud metallicity, initial rotation energy and
initial cloud shape. For different combinations of these parameters, we
calculate 480 models in total and study cloud evolution, fragmentation
conditions, orbital separation and binary frequency. For the cloud to fragment
during collapse, the initial angular momentum must be higher than a threshold
value, which decreases with decreasing metallicity. Although the exact
fragmentation conditions depend also on the initial cloud shape, this
dependence is only modest. Our results indicate a higher binary frequency in
lower-metallicity gas. In particular, with the same median rotation parameter
as in the solar neighbourhood, a majority of stars are born as members of
binary/multiple systems for < 10^-4 Z_sun. With initial mass < 0.1 M_sun, if
fragments are ejected in embryo from the host clouds by multi-body interaction,
they evolve to substellar-mass objects. This provides a formation channel for
low-mass stars in zero- or low-metallicity environments.Comment: Accepted for publication in MNRAS. High resolution figures are
available at
http://www2-tap.scphys.kyoto-u.ac.jp/~machidam/astro-ph/metallicity.pd
Gremlin Enhances the Determined Path to Cardiomyogenesis
BACKGROUND: The critical event in heart formation is commitment of mesodermal cells to a cardiomyogenic fate, and cardiac fate determination is regulated by a series of cytokines. Bone morphogenetic proteins (BMPs) and fibroblast growth factors have been shown to be involved in this process, however additional factors needs to be identified for the fate determination, especially at the early stage of cardiomyogenic development. METHODOLOGY/PRINCIPAL FINDINGS: Global gene expression analysis using a series of human cells with a cardiomyogenic potential suggested Gremlin (Grem1) is a candidate gene responsible for in vitro cardiomyogenic differentiation. Grem1, a known BMP antagonist, enhanced DMSO-induced cardiomyogenesis of P19CL6 embryonal carcinoma cells (CL6 cells) 10-35 fold in an area of beating differentiated cardiomyocytes. The Grem1 action was most effective at the early differentiation stage when CL6 cells were destined to cardiomyogenesis, and was mediated through inhibition of BMP2. Furthermore, BMP2 inhibited Wnt/beta-catenin signaling that promoted CL6 cardiomyogenesis. CONCLUSIONS/SIGNIFICANCE: Grem1 enhances the determined path to cardiomyogenesis in a stage-specific manner, and inhibition of the BMP signaling pathway is involved in initial determination of Grem1-promoted cardiomyogenesis. Our results shed new light on renewal of the cardiovascular system using Grem1 in human
N-Body Simulation of Planetesimal Formation through Gravitational Instability and Coagulation. II. Accretion Model
The gravitational instability of a dust layer is one of the scenarios for
planetesimal formation. If the density of a dust layer becomes sufficiently
high as a result of the sedimentation of dust grains toward the midplane of a
protoplanetary disk, the layer becomes gravitationally unstable and
spontaneously fragments into planetesimals. Using a shearing box method, we
performed local -body simulations of gravitational instability of a dust
layer and subsequent coagulation without gas and investigated the basic
formation process of planetesimals. In this paper, we adopted the accretion
model as a collision model. A gravitationally bound pair of particles is
replaced by a single particle with the total mass of the pair. This accretion
model enables us to perform long-term and large-scale calculations. We
confirmed that the formation process of planetesimals is the same as that in
the previous paper with the rubble pile models. The formation process is
divided into three stages: the formation of non-axisymmetric structures, the
creation of planetesimal seeds, and their collisional growth. We investigated
the dependence of the planetesimal mass on the simulation domain size. We found
that the mean mass of planetesimals formed in simulations is proportional to
, where is the size of the computational domain in the
direction of rotation. However, the mean mass of planetesimals is independent
of , where is the size of the computational domain in the radial
direction if is sufficiently large. We presented the estimation formula
of the planetesimal mass taking into account the simulation domain size.Comment: 24 pages, 13 figures,Accepted for publication in Ap
Severe sepsis caused by Aeromonas hydrophila in a patient using tocilizumab: a case report
<p>Abstract</p> <p>Introduction</p> <p><it>Aeromonas </it>species do not commonly cause disease in humans. However, when disease is seen, it often occurs in patients with underlying immunosuppression or malignancy and has a high fatality rate.</p> <p>Case presentation</p> <p>A 72-year-old Japanese woman with rheumatoid arthritis treated with tocilizumab (which has an immunosuppressive effect) presented with severe epigastric pain. She had a fever with chills, hypotension and jaundice. She was diagnosed with acute suppurative cholangitis and treated with cefoperazone-sulbactam and an endoscopic drainage was performed. Jaundice was slightly improved, but the shock state and inflammatory reactions were prolonged as typical of septic shock. On the second day after admission, an electrocardiogram showed ST segment elevation and echocardiography showed ventricular wall dysfunction. Coronary arteries were patent in coronary angiography and she was diagnosed with stress-induced cardiomyopathy. Blood cultures showed <it>Aeromonas hydrophila</it>. A stool culture was negative for <it>A. hydrophila</it>. On day six, her white blood cell count and neutrophils were normalized and cefoperazone-sulbactam treatment was halted. Left ventricular function normalized on day twelve and a laparoscopic cholecystectomy for cholelithiasis was performed on the 16th day of hospitalization. A culture from the bile showed <it>A. hydrophila</it>. Eighteen days after surgery, tocilizumab treatment was restarted and there were no complications. Two months after restarting tocilizumab, our patient is stable without any serious events.</p> <p>Conclusion</p> <p>We present a rare case of <it>A. hydrophila </it>sepsis and acute suppurative cholangitis in an elderly patient with gallstones and rheumatoid arthritis using tocilizumab. This clinical course may suggest that preemptive treatment for cholelithiasis prior to using molecular-targeting agents might be feasible in elderly patients.</p
-body Simulation of Planetesimal Formation Through Gravitational Instability of a Dust Layer
We performed N-body simulations of a dust layer without a gas component and
examined the formation process of planetesimals. We found that the formation
process of planetesimals can be divided into three stages: the formation of
non-axisymmetric wake-like structures, the creation of aggregates, and the
collisional growth of the aggregates. Finally, a few large aggregates and many
small aggregates are formed. The mass of the largest aggregate is larger than
the mass predicted by the linear perturbation theory. We examined the
dependence of system parameters on the planetesimal formation. We found that
the mass of the largest aggregates increase as the size of the computational
domain increases. However the ratio of the aggregate mass to the total mass
is almost constant . The mass of
the largest aggregate increases with the optical depth and the Hill radius of
particles.Comment: 34 pages, 11 figures. Accepted for publication in Ap
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