Double radiofrequency ablation is more extensive with a spherical zone shape compared to single ablation in a pig liver model

Objective : We compared the duration of ablation and the area of coagulation necrosis between a single ablation method (SAM) and a double ablation method (DAM) with a ’multitined expandable’ electrode (LeVeen 2cm) for radiofrequency ablation (RFA) using pig liver. Method : In the SAM group, ablation was completed after the first roll-off. In the DAM group, an additional ablation was performed to achieve a second roll-off. The comparison was made of the time required for roll-off and the extent of coagulation necrosis between the both groups. The Ellipticity index (EI) quantitatively describes the shape of the general RF ablation zone in the axial plane. Results : There was no statistically significant difference in the interval until the first roll-off between both groups (SAM group : 100.7±24.7 seconds vs DAM group : 103.2±37.7 seconds, P=0.43). In the DAM group, the interval from the start of the additional ablation until the second roll-off was 154.0±86.9 seconds, longer than the interval for the first roll-off (P=0.023). The extent of coagulation necrosis was significantly more extensive in the DAM group (axial diameter, mean±SD, 26.2±2.8 mm)×(maximal diameter : 29.3±1.6 mm)× (minimal diameter : 26.5±3.6 mm) compared to the SAM group with (23.0±3.3 mm)×(23.7± 3.1 mm)×(20.0±2.5 mm), respectively. Although there was no statistically significant difference in the EI between both groups, macroscopically, the shape of coagulation necrosis tended to be non-spherical in the SAM group and spherical in the DAM group. Conclusions : The DAM with a ’multitined expandable’ electrode was more extensive with a spherical zone shape compared to the SAM

Identification and Modulation of the Key Amino Acid Residue Responsible for the pH Sensitivity of Neoculin, a Taste-Modifying Protein

Neoculin occurring in the tropical fruit of Curculigo latifolia is currently the only protein that possesses both a sweet taste and a taste-modifying activity of converting sourness into sweetness. Structurally, this protein is a heterodimer consisting of a neoculin acidic subunit (NAS) and a neoculin basic subunit (NBS). Recently, we found that a neoculin variant in which all five histidine residues are replaced with alanine elicits intense sweetness at both neutral and acidic pH but has no taste-modifying activity. To identify the critical histidine residue(s) responsible for this activity, we produced a series of His-to-Ala neoculin variants and evaluated their sweetness levels using cell-based calcium imaging and a human sensory test. Our results suggest that NBS His11 functions as a primary pH sensor for neoculin to elicit taste modification. Neoculin variants with substitutions other than His-to-Ala were further analyzed to clarify the role of the NBS position 11 in the taste-modifying activity. We found that the aromatic character of the amino acid side chain is necessary to elicit the pH-dependent sweetness. Interestingly, since the His-to-Tyr variant is a novel taste-modifying protein with alternative pH sensitivity, the position 11 in NBS can be critical to modulate the pH-dependent activity of neoculin. These findings are important for understanding the pH-sensitive functional changes in proteinaceous ligands in general and the interaction of taste receptor–taste substance in particular

Influence of an artificial pleural effusion technique on cardio-pulmonary function and autonomic activity

Objective : Percutaneous treatment of hepatocellular carcinoma (HCC) located directly under the diaphragm is problematic because ultrasonic imaging is difficult, and the lung may be injured during the procedure. It has been reported that an infusion of 5% glucose solution into the thoracic cavity enables percutaneous treatment in such cases. However, the safety aspects of this have not been investigated. In this study, variations in heart rate and changes in circulatory and respiratory dynamics were examined during the infusion of artificial pleural effusion directly under the diaphragm in patients with HCC. Method : The subjects were 13 patients with an HCC directly under the diaphragm. About 500 ml of a 5% glucose solution was infused into the thoracic cavity, and mean blood pressure, heart rate, and oxygen saturation were measured. Holter electrocardiography was simultaneously recorded to evaluate autonomic nerve function. To analyze variations in heart rate, the low-frequency waves (LF : 0.04-0.15 Hz), high-frequency waves (HF : 0.15-0.40 Hz, an index of parasympathetic nerve activity), and the LF/HF ratio (index of sympathetic nerve activity) were examined. The above parameters were measured before, during (when infusion of the half the planned volume was complete), and after infusion were compared. Results : No significant changes in the mean blood pressure or heart rate were found. Oxygen saturation was significantly decreased during and after the infusion. The HF value was slightly higher after infusion and the LF value was significantly increased during infusion. The LF/HF ratio was significantly increased during infusion, and this increase persisted after infusion. Conclusions : The infusion of artificial pleural effusion had no effect on circulatory dynamics, but transiently affected respiratory functions. It was also revealed that infusion stimulated the parasympathetic nerves

Interferon-α enhances biological defense activities against oxidative stress in cultured rat hepatocytes and hepatic stellate cells

Oxidative stress has been implicated as a cause of hepatic fibrosis, and hepatic stellate cells (HSCs), which are the most important collagen-producing cell types, have been reported to be activated by lipid peroxidation products. Antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPx) provide a defense system that plays a critical role in protecting the cell from free radical damage, particularly lipid peroxidation. To elucidate the antioxidant activity of interferon-α (IFN-α), the effects of IFN-α on rat hepatocytes undergoing oxidative stress and HSCs in primary culture as well as isolated rat liver mitochondria were examined. IFN-α was observed to dose-dependently increase the immunoreactive protein levels of copper, zinc-and manganese-dependent SOD as well as the enzyme activities of GPx, and decrease the lipid peroxidation product levels and oxidative burst both in stressed hepatocytes and activated HSCs GPx activities, however, were not detected in the latter cells. IFN-α also inhibited HSC activation and lipid peroxidation in liver mitochondria. These findings suggest that IFN-α may enhance biological defense activities against oxidative stress and function as a potent fibrosuppressant by protecting hepatocytes and hepatic stellate cells from lipid peroxidation in vivo

Opposing effects of estradiol and progesterone on the oxidative stress-induced production of chemokine and proinflammatory cytokines in murine peritoneal macrophages

In inflammatory and oxidative liver injury, virus proteins and reactive oxygen species are involved in the regulation of proinflammatory cytokine production by macrophages. This study investigated the effects of estradiol (E2) and progesterone on the unstimulated and oxidative stress-stimulated production of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, macrophage inflammatory protein (MIP)-2, and macrophage chemotactic protein (MCP)-1 by peritoneal macrophages isolated from male and female mice. E2 inhibited the cytokine production of TNF-α, IL-1β, MIP-2, and MCP-1 by the unstimulated macrophages from males and females, which was then further stimulated by progesterone. The exposure to hydrogen peroxide in the macrophages from both sexes induced the production of cytokine. The hydrogen peroxide-stimulated cytokine production was suppressed by E2 and enhanced by progesterone. The sex hormone effects on the unstimulated and stimulated macrophages were blocked by their receptor antagonists and showed no significant difference between male and female subjects. These findings suggest that E2 may play a favorable role in the course of persistent liver injury, by inhibiting proinflammatory cytokine production, which, in addition, progesterone may counteract the favorable E2 effects through their receptors

Relationship of Grade of Malignant Brain Tumor to Cancer Stem Cells and Survivin Expression

Glioblastoma (GBM) is difficult to completely cure by surgical treatment alone, and it is generally treated with a combination of surgery, radiotherapy, and chemotherapy. However, GBM is resistant to radiotherapy and chemotherapy, and complete cure cannot be achieved. Cancer stem cells (CSC) and survivin, which inhibit apoptosis, are considered as factors underlying tumor recurrence and the radiation- and drug-resistance of these tumors. We analyzed CSC and survivin expression in surgically excised specimens of malignant brain tumors to establish the relationships between the grades and CSC and survivin expression and between MIB-1 (Ki-67) expression and resistance. No relationship was noted between the grades and CSC or survivin expression, or between MIB-1 and CSC expression or between Grade 3 and 4 MIB-1 and survivin expression, although a correlation was noted between MIB-1 and survivin expression in Grade II tumors. These findings suggested that CSC are consistently contained in tumor tissue at a specific rate regardless of the histological grade, and the apoptosis of cells with low-level proliferative and cell cycling activities does not occur because these cells do not respond to chemotherapy or radiation, being resistant to treatment

Present Status in the Development of 6 MeV Heavy Ion Beam Probe on LHD

In order to measure the potential in Large Helical Device (LHD), we have been developing a heavy ion beam probe (HIBP). For probing beam, gold beam is used, which is accelerated by a tandem accelerator up to the energy of 6 MeV. The experiments for calibration of beam orbit were done, and experimental results were compared with orbit calculations. The experimental results coincided fairly with the calculation results. After the calibration of the beam orbit, the potential in plasma was tried to measure with the HIBP. The experimental data showed positive potential in a neutral beam heating phase on the condition of ne ? 5 × 10^18 m^-3, and the increase of potential was observed when the additional electron cyclotron heating was applied to this plasma. The time constant for this increase was about a few tens ms, which was larger than a theoretical expectation. In the spatial position of sample volume, we might have an ambiguity in this experiment

トウカ ニオケル ラジオハ ショウシャク リョウホウ オ モチイタ カンシュヨウ チリョウ : preliminary report

Radiofrequency ablation (RFA) has recently been used to treat liver tumors. RFA is a safe and effective treatment of liver tumors and requires fewer treatment sessions. Between June 2000 and April 2003, hepatocellular carcinoma (77 patients with 106 lesions) and metastatic liver tumors (21 patients with 30 lesions) and cholangiocellular carcinoma (1 patient with 1 lesion) were treated with RFA. The liver tumors were treated percutaneously or during surgery under ultrasound guidance using a LeVeen needle (55 lesions) and cool tip RF needle (82 lesions). To evaluate the response, contrast-enhanced CT scans or MRI were obtained. Most patients experienced moderate pain during RFA procedure, especially when the tumor was superficially located. Complete necrosis was achieved in all HCCs with RFA.This result was obtained with an average of 1.12 sessions per HCC. With a median follow-up of 15 months, HCCs have recurred in 6 of 90 treated lesions (6.7%), and metastatic liver tumors have recurred in 2 of 17 treated lesions (11.8%). We are initiating a combining RFA of hepatic malignancies with regional or systemic chemotherapy will reduce hepatic and extrahepatic recurrence rates and enhance long-term survival rates. We believe that RFA will be effective treatment to achieve in patients with unresectable meastatic liver tumors

Theoretical calculation of cesium deposition and co-deposition with electronegative elements on the plasma grid in negative ion sources

We studied the work function of cesium deposition and co-deposition with the electronegative element on the plasma grid (PG) using the first-principles calculations. The impurity particles may exist in the background plasma and vacuum chamber wall, and the work function of the PG will be affected. The results indicate that the minimum work functions of pure cesium deposition on Mo (110), W (110), and Mo (112) are reached at a partial monolayer. They are 1.66 eV (σ = 0.56 θ), 1.69 eV (σ = 0.75 θ), and 1.75 eV (σ = 0.88 θ), respectively. An appropriate co-deposition model consisting of cesium with electronegative elements can further decrease the work function. The coverage of cesium and electronegative elements are both 0.34 θ in all the co-deposition models. The F-Cs co-deposition model where the Cs atom and F atom are aligned along the surface normal obtains the lowest work function. They are 1.31 eV for F-Cs on Mo (110), and 1.23 eV for F-Cs on W (110), respectively. The change in work function is linearly related to the change in dipole moment density with a slope of −167.03 VÅ. For pure cesium deposition, two factors control the change in dipole-moment density, one is the electron transfer between adsorbates and the substrate, and another one is the restructuring of surface atoms. There are two additional factors for the co-deposition model. One is the intrinsic dipole moment of the double layer, the other is the angle between the intrinsic dipole moment and the surface. The latter two factors play important roles in increasing the total dipole moment