Near-Infrared and X-Ray Observations of XSS J12270-4859

XSS J12270-4859 (J12270) is an enigmatic source of unknown nature. Previous studies revealed that the source has unusual X-ray temporal characteristics, including repetitive short-term flares followed by spectral hardening, non-periodic dips, and dichotomy in activity; i.e. intervals filled with flares and those without. Together with a power-law X-ray spectrum, it is suggested to be a low-mass X-ray binary (LMXB). In order to better understand the object, we present the results of our near-infrared (NIR) photometry and linear polarimetry observations as well as X-ray spectroscopy observations, which overlap with each other partially in time, taken respectively with the InfraRed Survey Facility (IRSF) and the Rossi X-ray Timing Explorer (RXTE). We detected several simultaneous NIR and X-ray flares for the first time. No significant NIR polarization was obtained. We assembled data taken with IRSF, RXTE, Suzaku, Swift, and other missions in the literature and compared the flare profile and the spectral energy distribution (SED) with some representative high-energy sources. Based on some similarities of the repetitive NIR and X-ray flaring characteristics and the broad SED, we argue that J12270 is reminiscent of microquasars with a synchrotron jet, which is at a very low luminosity state of ~1e-4 Eddington luminosity for a stellar mass black hole or neutron star at a reference distance of 1 kpc.Comment: 12 pages, 9 figures, accepted for publication in PAS

Fragmentation of Protein Kinase N (PKN) in the Hydrocephalic Rat Brain

PKN (protein kinase N; also called protein kinase C-related kinase (PRK-1)), is a serine/threonine protein kinase that is ubiquitously expressed in several organs, including the brain. PKN has a molecular mass of 120 kDa and has two domains, a regulatory and a catalytic domain, in its amino-terminals and carboxyl-terminus, respectively. Although the role of PKN has not been fully elucidated, previous studies have revealed that PKN is cleaved to a constitutively active catalytic fragment of 55 kDa in response to apoptotic signals. Hydrocephalus is a pathological condition caused by insufficient cerebrospinal fluid (CSF) circulation and subsequent excess of CSF in the brain. In this study, in order to elucidate the role of PKN in the pathophysiology of hydrocephalus, we examined PKN fragmentation in hydrocephalic model rats

Analysis of Delayed Bleeding after Endoscopic Submucosal Dissection for Gastric Epithelial Neoplasms

Aim. Delayed bleeding after endoscopic submucosal dissection (ESD) for gastric epithelial neoplasms is a major complication. We investigated factors related to post-ESD bleeding to identify preventive measures. Methods. The study included 161 gastric epithelial neoplasms in 142 patients from June 2007 to September 2010. Post-ESD bleeding was defined as an ulcer with active bleeding or apparent exposed vessels diagnosed by an emergency endoscopy or a planned follow-up endoscopy. We analyzed associations between bleeding and the following factors: age, sex, morphology, pathology, tumor depth, ulcer presence/absence, location, size of the resected lesion, duration of the procedure, the number of times bleeding occurred during ESD, and the use of anticoagulants and/or antiplatelet drugs. Subsequently, we examined characteristics of bleeding cases. Results. Post-ESD bleeding occurred in 21 lesions. Univariate analysis of these cases showed that ulcer presence/absence (P < 0.001), middle or lower third lesions (P = 0.036), circumference (P = 0.014), and a post-ESD ulcer with an extended lesser curve (P = 0.009) were significant predictors of bleeding. Multivariate analysis showed that ulcer presence/absence (OR 9.73, 95% CI 2.28–41.53) was the only significant predictor. Conclusion. Ulcer presence/absence was considered the most significant predictor of post-ESD bleeding

Absorption characteristics of compounds with different molecular weights after application to the unilateral kidney surface in rats

The aim of the present study is to clarify the absorption mechanism of a drug from the kidney surface membrane in rats. We studied the absorption characteristics of phenolsulfonphthalein (PSP) and other compounds with different molecular weights after their application to the rat kidney surface in vivo, employing a cylindrical diffusion cell (i.d. 6 mm, area 0.28 cm2). The time course of free PSP amounts remaining in the diffusion cell obeyed first-order kinetics at a dose of 1 mg, and its rate constant ka was calculated to be 0.0137 min?1. Absorption ratios of PSP in 4 h were calculated (from the amount recovered from the diffusion cell) to be 91.4, 96.4 and 97.7% at doses of 0.5, 1 and 1.5 mg, respectively. The area under the curve for the plasma concentration profile of free PSP was proportional to the application dose. It is thus suggested that the absorption process of PSP from the rat kidney surface does not approach saturation at a dose of 1.5 mg. Also, no significant difference was seen in the ka values within the dose range of 0.5?1.5 mg, which were estimated by curve-fitting the plasma concentration profiles of free PSP in a two-compartment model with first-order absorption. Furthermore, we examined the importance of molecular weight on the absorption from the kidney surface using fluorescein isothiocyanate-dextrans (FDs) with molecular weights of 4400 (FD-4), 11,000 (FD-10), 40,500 (FD-40) or 69,000 (FD-70), including the organic anions bromphenol blue and bromosulfonphthalein. The absorption ratios of FDs from the rat kidney surface in 6 h decreased with an increase in the molecular weight (76.1% for FD-4, 54.4% for FD-10, 11.5% for FD-40 and 3.9% for FD-70). A linear relationship was observed between ka and the reciprocal value of z the square root of the molecular weight of these compounds. The limit of absorption from the rat kidney surface was extrapolated to be at a molecular weight of approximately 130,000

Effect of application volume and area on the absorption of phenol red as a model drug from the liver surface in rats

We examined the importance of application volume and area in the absorption of phenol red as a model drug from the rat liver surface, for pharmaceutical formulation concerning administration form. When 1 mg of phenol red was applied to the rat liver surface in-vivo using a cylindrical glass cell (i.d. 9 mm) in three volumes (0.1, 0.2 or 0.334 mL), the shape of the plasma concentration pattern differed greatly, particularly the maximum concentration. These patterns were well fitted by a two-compartment model with first-order absorption, and the obtained absorption rate constant Ka decreased inversely according to the application volume. The absorption ratio and biliary recovery of phenol red at 6 h was increased with glass cell area (i.d. 6, 9 or 14 mm; area 0.28, 0.64 or 1.54 cm2). Furthermore, the permeability coefficient Papp derived from Ka did not depend on application area, indicating no difference in absorption characteristics of liver surface. This also implies transport of a drug by a passive diffusion from the liver surface. After intraperitoneal administration to the rat liver surface for clinical application, increase in application volume resulted in the delayed disappearance of phenol red from plasma. However, the difference was not as marked as that using a glass cell. The assumption that the effective area relating to the absorption changed with the application volume enabled us to estimate Papp. Consequently, we speculate absorbability can be estimated precisely by considering application volume and area

Rapid detection of hypoxia-inducible factor-1-active tumours: pretargeted imaging with a protein degrading in a mechanism similar to hypoxia-inducible factor-1alpha

PURPOSE: Hypoxia-inducible factor-1 (HIF-1) plays an important role in malignant tumour progression. For the imaging of HIF-1-active tumours, we previously developed a protein, POS, which is effectively delivered to and selectively stabilized in HIF-1-active cells, and a radioiodinated biotin derivative, (3-(123)I-iodobenzoyl)norbiotinamide ((123)I-IBB), which can bind to the streptavidin moiety of POS. In this study, we aimed to investigate the feasibility of the pretargeting method using POS and (123)I-IBB for rapid imaging of HIF-1-active tumours. METHODS: Tumour-implanted mice were pretargeted with POS. After 24 h, (125)I-IBB was administered and subsequently, the biodistribution of radioactivity was investigated at several time points. In vivo planar imaging, comparison between (125)I-IBB accumulation and HIF-1 transcriptional activity, and autoradiography were performed at 6 h after the administration of (125)I-IBB. The same sections that were used in autoradiographic analysis were subjected to HIF-1alpha immunohistochemistry. RESULTS: (125)I-IBB accumulation was observed in tumours of mice pretargeted with POS (1.6%ID/g at 6 h). This result is comparable to the data derived from (125)I-IBB-conjugated POS-treated mice (1.4%ID/g at 24 h). In vivo planar imaging provided clear tumour images. The tumoral accumulation of (125)I-IBB significantly correlated with HIF-1-dependent luciferase bioluminescence (R=0.84, p<0.01). The intratumoral distribution of (125)I-IBB was heterogeneous and was significantly correlated with HIF-1alpha-positive regions (R=0.58, p<0.0001). CONCLUSION: POS pretargeting with (123)I-IBB is a useful technique in the rapid imaging and detection of HIF-1-active regions in tumours

Synthesis of a Novel Pyrazine-Pyridone Biheteroaryl-Based Fluorescence Sensor and Detection of Endogenous Labile Zinc Ions in Lung Cancer Cells

A small extent of endogenous labile zinc is involved in many vital physiological roles in living systems. However, its detailed functions have not been fully elucidated. In this study, we developed a novel biheteroaryl-based low molecular weight fluorescent sensor, 3-(phenylsulfonyl)-pyrazine-pyridone (5b), and applied it for the detection of endogenous labile zinc ions from lung cancer cells during apoptosis. The electron-withdrawing property of the sulfonyl group between the phenyl ring as an electron donor and the pyridone ring as a fluorophore inhibited the intramolecular charge transfer state, and the background fluorescence of the sensor was decreased in aqueous media. From the structure-fluorescence relationship analysis of the substituent effects with/without Zn 2+ , compound 5b acting as a sensor possessed favorable properties, including a longer emission wavelength, a large Stokes shift (over 100 nm),a large fluorescence enhancement in response to Zn 2+ under physical conditions, and good cell membrane permeability in living cells. Fluorescence imaging studies of human lung adenocarcinoma cells (A549) undergoing apoptosis revealed that compound 5b could detect endogenous labile zinc ions. These experiments suggested that the low molecular weight compound 5b is a potential fluorescence sensor for Zn 2+ toward understanding its functions in living systems

Absorption of phenolsulfonphthalein as a model across the mesenteric surface in rats to determine the drug absorption route after intraperitoneal administration

The purpose of this study is to clarify absorption characteristics of a drug across the mesenteric surface which occupies a large area of absorption in the peritoneal cavity in order to determine the drug absorption route after intraperitoneal administration. Absorption of phenolsulfonphthalein (PSP) as a model after application to the mesenteric surface was investigated in rats, by employing a cylindrical diffusion cell attached to the mesentery with or without blood vessels. PSP was absorbed from the rat mesenteric surface, followed by its appearance in the plasma and bile, regardless of blood vessel existence. The absorption ratios of PSP in 6 h were calculated to be 92.1 % and 83.6 % from the mesenteric surface with and without blood vessels, respectively. We then employed an experimental system by sticking a polyethylene cap (PE cap) on the surface of the other side to exclude the influence of absorption of the drug from the other organ surfaces that penetrated across the mesentery. The PE cap-sticking decreased the appearance of PSP in the plasma from the mesenteric surface with blood vessels and eliminated the PSP absorption completely from the mesenteric surface without blood vessels. Accordingly, blood vessels on the mesenteric surface actually play an important role in drug absorption, but the contribution of the mesenteric surface to drug absorption from the peritoneal cavity is unlikely to be significant due to there being a small effective area of blood vessels

Case report: A case of fetal umbilical vein varix presenting disseminated intravascular coagulation, polycythemia, and neonatal hepatitis in an extremely low birth weight infant

Reports on the clinical course of fetal umbilical vein varix in premature infants are limited. We report a case of an extremely low body weight infant with intra-abdominal umbilical vein varix who developed disseminated intravascular coagulation, polycythemia, and hyperbilirubinemia after birth; late-onset neonatal hepatitis; and fetal thrombotic vasculopathy confirmed by placental histopathology. Ultrasonography after birth showed a dilated portion of the umbilical vein at the hepatic hilum with thrombi inside. We speculate that the umbilical vein varix caused the fetal thrombotic vasculopathy, and the presence of umbilical vein varix and fetal thrombotic vasculopathy in combination with prematurity caused coagulopathy, polycythemia, hyperbilirubinemia, and hepatitis. Despite the favorable outcomes reported in the literature, premature infants with umbilical vein varix may require careful observation and management for coagulopathy and late-onset hepatitis. Furthermore, placental histopathology could aid in the understanding of various clinical outcomes in infants with umbilical vein varices

Generation of third-harmonic spin oscillation from strong spin precession induced by terahertz magnetic near fields

The ability to drive a spin system to state far from the equilibrium is indispensable for investigating spin structures of antiferromagnets and their functional nonlinearities for spintronics. While optical methods have been considered for spin excitation, terahertz (THz) pulses appear to be a more convenient means of direct spin excitation without requiring coupling between spins and orbitals or phonons. However, room-temperature responses are usually limited to small deviations from the equilibrium state because of the relatively weak THz magnetic fields in common approaches. Here, we studied the magnetization dynamics in a HoFeO3 crystal at room temperature. A custom-made spiral-shaped microstructure was used to locally generate a strong multicycle THz magnetic near field perpendicular to the crystal surface; the maximum magnetic field amplitude of about 2 T was achieved. The observed time-resolved change in the Faraday ellipticity clearly showed second- and third-order harmonics of the magnetization oscillation and an asymmetric oscillation behaviour. Not only the ferromagnetic vector M but also the antiferromagnetic vector L plays an important role in the nonlinear dynamics of spin systems far from equilibrium