Background: Portal hypertension is often accompanied by a hyperdynamic circulation state. Some reports have suggested that nitric oxide (NO) plays an important role in this hyperdynamic state. On the ...other hand, although endothelin (ET)-1, a powerful vasoconstrictor, was recently identified, little is known about its role in portal hypertension or about the interaction between NO and ET-1. The aim of this study was therefore to investigate whether or not the inhibitor of NO synthase (NOS) might improve portal hypertension, and also to clarify the relationship between NO and ET-1. Methods: Portal hypertensive (PHT) rats, in which hypertension was induced by a two-step ligation of the portal vein (PVL), were used. The mean arterial pressure (MAP), portal pressure (PP), visceral blood flow volume (BFV), and serum levels of NO and ET-1 were determined in PVL rats treated with two NOS inhibitors with different functions: NG-nitro-L-arginine methyl ester (L-NAME) and aminoguanidine (AG). Control (CTR) rats, treated by a sham operation (SO), were also studied. Results: Two-step PVL treatment induced a significant increase in the serum level of NO3- and ET-1 in the portal vein. L-NAME and AG administration significantly decreased PP at doses of 50 mg/kg in PHT rats after 60 min administration, while no inhibitor effected any modification in the CTR rats. Both NOS inhibitors increased MAP and decreased PP and BFV in the portal vein, gastric mucosa, and spleen, in addition to decreasing the serum levels of NO3- and ET-1 in the PHT rats, while neither blockade modified any parameters in the CTR rats. In PHT rats, L-arginine, a NO substance, reversed the effect of L-NAME, while it did not induce any recovery from the AG effect. Conclusions: In PHT rats, NO seems to contribute to portal hypertension. PVL increases not only the serum level of NO3-, but also that of ET-1 in the portal vein. Both L-NAME and AG reduce PP and BFV of the portal vein, spleen, gastric mucosa, and liver. In addition, the inhibition of NOS diminishes the serum level not only of NO, but also of ET-1. Use of an appropriate NOS inhibitor may therefore positively affect the hyperdynamic state in portal hypertension.
Regulation of angiogenesis by nitric oxide (NO) is controversial since NO has been shown to have both pro- and anti-angiogenic effects. In this study, we examined the effect of the NO donor,
S-nitro-
...N-acetyl-penicillamine (SNAP), on in vitro angiogenesis, and the mechanisms involved: PKC activity, ERK and c-Jun phosphorylation, and AP-1 DNA binding activity, in microvascular endothelial cells. SNAP, at 0.5–4
mM, significantly and dose-dependently inhibited angiogenesis, PKC activity, and ERK and c-Jun phosphorylation up to 80%, 83%, and 63% and 73%, respectively. SNAP at concentrations >2
mM also abolished AP-1 binding activity. Lower concentrations of SNAP (0.1–0.3
mM) significantly increased angiogenesis, PKC activity, and ERK and c-Jun phosphorylation up to 46%, 60%, and 61% and 180%, respectively. These findings indicate that the dual pro- and anti-angiogenic actions of NO are dose-dependent and suggest that they are mediated by PKC and ERK acting on AP-1.
Photolysis of perfluoroazooctane with diamond films led the chemical modification of the surface to introduce perfluorooctyl functional group, confirming by means of FT-IR, XPS, Raman and TOF-SIMS ...measurements. The diamond films modified with fluorine moiety showed improvement of reduction of surface energy evaluated by contact angle 118° to water, compared with pristine diamond film.
In the 1990s, laparoscopic surgery entirely changed the traditional style of surgical operations. Laparoscopic cholecystectomy has spread rapidly and is now established as the standard treatment. ...However, besides cholecystectomy, endoscopic procedures are still not applied so widely to a variety of surgical operations. This is because laparoscopic techniques, such as suturing or ligation, make it difficult for surgeons to perform other kinds of operations and thus greatly increase their mental and physical stress. It is necessary to introduce various advanced technologies such as: surgical robots, three dimensional (3D) images, computer graphics (CG), computer simulation technology and others. Surgical robots, including the AESOP, da Vinci and ZEUS systems, provide surgeons with technologically advanced vision and hand skills. As a result, such systems are expected to revolutionize the field of surgery. However, there have so far been few studies which discuss the indications of robotic surgery for tumors/cancer. Therefore, herein we review various studies published in English to focus on the application of robotic surgery to tumors/cancer. We point out that there are several problems to be solved for robot surgery: i) price of surgical robots, ii) training systems for surgeon, iii) coverage by medical insurance, iv) downsizing and v) navigation system. In conclusion, we believe that, in the near future as robotic technology continues to develop, almost all kinds of endoscopic surgery will be performed by this technology. It will replace traditional surgery not only in the treatment of benign diseases but also in malignant illnesses.
The Central Solenoid Model Coil (CSMC) was designed and built by an ITER collaboration in 1993-2001. Three heavily instrumented Inserts have been also built for testing in the background field of the ...CSMC. The Nb/sub 3/Al Insert was designed and built by Japan to explore the feasibility of an alternative to Nb/sub 3/Sn superconductor for fusion magnets. The Nb/sub 3/Al Insert coil was tested in the CSMC Test Facility at the Japan Atomic Energy Research Institute, Naka, Japan in March-May 2002. It was the third Insert tested in this facility under this program. The Nb/sub 3/Al Insert coil was charged successfully without training in the background field of the CSMC to the design current of 46 kA at 13 T peak field and later was successfully charged up to 60 kA in 12.5 T field. This paper presents the test results overview.
Metal-oxide-semiconductor field effect transistors (MOSFETs) with a surface p-channel have been fabricated on hydrogen-terminated diamond (001) surfaces without doping. The maximum transconductance ...of the device with the gate length of 6 μm is 16 mS/mm, which is the highest in diamond MOSFETs and comparable to that of silicon n-channel MOSFET with the same gate length. The relatively high transconductance is due to the low density of surface states on hydrogen-terminated diamond. The diamond MOSFETs operate at the temperatures of up to 330°C in air without any passivation of the device surfaces.
MOSFETs on polished polycrystalline diamond surfaces have been fabricated. The best transconductance is 1.0
mS/mm. The breakdown voltages of these FETs are over 200
V, comparable to those reported in ...homoepitaxial diamond MESFETs. A polycrystalline diamond FET is a candidate for sensors in hard environment, due to its feasibility in large-area wafers.
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