ウサギ味蕾細胞におけるAMP-PNP加水分解酵素の細胞化学的研究 : ATPピロホスファターゼおよびアデニル酸シクラーゼの抑制物質・賦活物質の効果

In the apical regions of rabbit taste bud cells, especially on the surface of the microvilli, there exists an enzymatic activity that hydrolyzes an ATP analogue, 5\u27-adenylylimi-dodiphosphate. Since our previous study had suggested that this activity was that of either ATP pyrophosphatase or adenylyl cyclase, the effects of inhibitors and activators of these enzymes on the enzymatic activity were examined cytochemically. ATP pyrophosphatase inhibitors (dithiothreitol, sodium fluoride and amiloride) reduced the enzymatic activity, while adenylyl cyclase inhibitors (p-chloromercuriphenylsulfonic acid and 5,5\u27-dithio-bis (2-nitrobenzoic acid)) did not. The effect of a mild activator of ATP pyrophosphatase (sodium azide) was not generally clear. Forskolin, a potent activator of adenylyl cyclase, did not show any enhancing effect. Ca^ enhanced the enzymatic activity. The results indicate that the enzymatic activity is that ofATP pyrophosphatase and probably that of Ca^-dependent type

Characterization of hydrothermal alteration along geothermal wells using unsupervised machine-learning analysis of X-ray powder diffraction data

Zonal distribution of hydrothermal alteration in and around geothermal fields is important for understanding the hydrothermal environment. In this study, we assessed the performance of three unsupervised classification algorithms—K-mean clustering, the Gaussian mixture model, and agglomerative clustering—in automated categorization of alteration minerals along wells. As quantitative data for classification, we focused on the quartz indices of alteration minerals obtained from rock cuttings, which were calculated from X-ray powder diffraction measurements. The classification algorithms were first examined by applying synthetic data and then applied to data on rock cuttings obtained from two wells in the Hachimantai geothermal field in Japan. Of the three algorithms, our results showed that the Gaussian mixture model provides classes that are reliable and relatively easy to interpret. Furthermore, an integrated interpretation of different classification results provided more detailed features buried within the quartz indices. Application to the Hachimantai geothermal field data showed that lithological boundaries underpin the data and revealed the lateral connection between wells. The method’s performance is underscored by its ability to interpret multi-component data related to quartz indices

Pravastatin restored the infarct size-limiting effect of ischemic preconditioning blunted by hypercholesterolemia in the rabbit model of myocardial infarction

AbstractOBJECTIVESWe tested to find out whether pravastatin restores the infarct size (IS)-limiting effect of ischemic preconditioning (IP) and if it has any effect on the IP-induced activation of adenosine producing enzyme ecto-5′-nucleotidase which plays a key role in the IP-induced cardioprotection.BACKGROUNDThe IS-limiting effect of IP is blunted by hypercholesterolemia. Recently, HMG-CoA reductase inhibitors are shown to have direct cytoprotective effects.METHODSRabbits were fed with a normal or cholesterol (1%) added diet with or without pravastatin (5 mg/kg/day) treatment. Infarct size was measured after 30 min occlusion and 3 h reperfusion of circumflex coronary artery with or without the IP procedure (5 min occlusion and 10 min reperfusion). Additionally, ecto-5′-nucleotidase activities of ischemic and nonischemic myocardium were measured immediately after IP procedure.RESULTSThis dose of pravastatin did not normalize the increased level of serum cholesterol. The IS-limiting effect of preceding IP (IS reduced from 36.7% to 9.6%, p < 0.001) was abolished by hypercholesterolemia (from 46.1% to 31.3%, p = NS) and restored by pravastatin treatment (from 35.2% to 9.4%, p < 0.001). Pravastatin treatment did not affect IS or the effect of IP under normocholesterolemia. The activation of ecto-5′-nucleotidase presented as the activity ratio of ischemic to nonischemic myocardium (3.1-fold in normocholesterolemia) was blunted by hypercholesterolemia (1.8-fold, p < 0.05) and restored by pravastatin treatment (2.9-fold).CONCLUSIONSPravastatin, at the dose serum cholesterol was not normalized, restored the IS-limiting effect of IP and IP-induced ecto-5′-nucleotidase activation, which were both blunted by hypercholesterolemia. The activation of ecto-5′-nucleotidase may be worth further investigation as a possible mechanism for the hypercholesterolemia-induced retardation and pravastatin-mediated restoration of the cardioprotective effect of IP

Japan Beyond-Brittle Project: Development of EGS Beyond Brittle-Ductile Transition

ABSTRACT New conventional geothermal energy projects have not been actively promoted in Japan for the last decade because of perceptions of high relative cost, limited electricity generating potential and the high degrees of uncertainties and associated risks of subsurface development. More recently however, EGS (Enhanced Geothermal System) geothermal has been identified as a most promising method of geothermal development because of its potential applicability to a much wider range of sites, many of which have previously been considered to be unsuitable for geothermal development. Meanwhile, some critical problems with EGS technologies have been experimentally identified, such as low recovery of injected water, difficulties in establishing universal design/development methodologies, and the occurrence of induced seismicity, suggesting that there may be limitations in realizing EGS in earthquake-prone compression tectonic zones. We propose a new concept of engineered geothermal development where reservoirs are created in ductile basement. This potentially has a number of advantages including: (a) simpler design and control of the reservoir, (b) nearly full recovery of injected water, (c) sustainable production, (d) lower cost when developed in relatively shallower ductile zones in compression tectonic settings, (e) large potential quantities of energy extraction from widely distributed ductile zones, (f) the establishment of a universal design/development methodology, and (g) suppression of felt earthquakes from/around the reservoirs. To further assess the potential of EGS reservoir development in ductile zones we have initiated the &quot;Japan Beyond-Brittle Project (JBBP)&quot;. It is intended that the first few years of the JBBP will be spent in basic scientific investigation and necessary technology development, including studies on rock mechanics in the brittle/ductile regime, characterization of ductile rock masses, development of modeling methodologies/technologies, and investigations of induced/triggered earthquakes. We expect to drill a deep experimental borehole that will penetrate the ductile zone in northeast Japan after basic studies are completed. The feasibility of EGS reservoir development in the ductile zone will then be assessed through observations and experimental results in the borehole

Constraining temperature at depth of the Kakkonda geothermal field, Japan, using Bayesian rock-physics modelling of resistivity: Implications to the deep hydrothermal system

Temperature-at-depth estimation is important for assessing supercritical geothermal resources. Bayesian rock-physics modelling of electrical resistivity is effective for estimating temperatures at depth. In this study, we improved a previously proposed Bayesian framework and demonstrated its effectiveness by estimating subsurface temperatures in the Kakkonda geothermal field, Japan. The proposed framework allows the estimation of either effective porosities or salinities in addition to temperatures; further, we were able to constrain the possible states of the crustal fluid at depth based on the estimates. The estimated 3D temperature structure was consistent with available deep temperature logs. Furthermore, the estimated results suggest the existence of a magmatic-hydrothermal system at depth in the field

Effects of beta-adrenergic blocking agents on specific binding of [3H]D-Ala2-Met5-enkephalinamide and [3H]naloxone.

To gain further insight into the central nervous system (CNS)-action of beta-adrenergic blocking agents (beta-blockers), we examined the effects of various kinds of beta-blockers on opioid receptors (Op-Rs) using radiolabeled receptor assay (RRA). We demonstrated that beta-blockers are competitively bound to Op-Rs in the CNS. Sodium index of beta-blockers in [3H]naloxone binding study indicated that beta-blockers had the mixed agonist-antagonist activity of opiates. The relative potency of beta-blockers in opioid RRA was negatively correlated with their membrane stabilizing activity. Neither beta-blocking activity nor intrinsic sympathomimetic activity was correlated with IC50 values of beta-blockers in opioid RRA. While it is widely accepted that beta-blockers have a tranquilizing activity, a part of the tranquilizing action of beta-blockers may be mediated through Op-Rs in the CNS. Although beta-blockers may have effects on their own receptors (beta-receptors) in the CNS, the more precise mechanisms of central action of these drugs must be further investigated.</p

IL-18 neutralization ameliorates obstruction-induced epithelial–mesenchymal transition and renal fibrosis

Ureteral obstruction results in renal fibrosis in part due to inflammatory injury. The role of interleukin-18 (IL-18), an important mediator of inflammation, in the genesis of renal fibrosis was studied using transgenic mice overexpressing human IL-18-binding protein. In addition, HK-2 cells were analyzed following direct exposure to IL-18 compared to control media. Two weeks after ureteral obstruction, the kidneys of wild-type mice had a significant increase in IL-18 production, collagen deposition, α-smooth muscle actin and RhoA expression, fibroblast and macrophage accumulation, chemokine expression, and transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α (TNF-α) production, whereas E-cadherin expression was simultaneously decreased. The transgenic mice with neutralized IL-18 activity exhibited significant reductions in these indicators of obstruction-induced renal fibrosis and epithelial– mesenchymal transition, without demonstrating alterations in TGF-β1 or TNF-α activity. Similarly, the HK-2 cells exhibited increased α-smooth muscle actin expression and collagen production, and decreased E-cadherin expression in response to IL-18 stimulation without alterations in TNF-α or TGF-β1 activity. Our study demonstrates that IL-18 is a significant mediator of obstruction-induced renal fibrosis and epithelial– mesenchymal transition independent of downstream TGF-β1 or TNF-α production

Induced seismicity associated with enhanced geothermal system

Enhanced Geothermal Systems (EGS) offer the potential to significantly add to the world energy inventory. As with any development of new technology, some aspects of the technology has been accepted by the general public, but some have not yet been accepted and await further clarification before such acceptance is possible. One of the issues associated with EGS is the role of microseismicity during the creation of the underground reservoir and the subsequent extraction of the energy. The primary objectives of this white paper are to present an up-to-date review of the state of knowledge about induced seismicity during the creation and operation of enhanced geothermal systems, and to point out the gaps in knowledge that if addressed will allow an improved understanding of the mechanisms generating the events as well as serve as a basis to develop successful protocols for monitoring and addressing community issues associated with such induced seismicity. The information was collected though literature searches as well as convening three workshops to gather information from a wide audience. Although microseismicity has been associated with the development of production and injection operations in a variety of geothermal regions, there have been no or few adverse physical effects on the operations or on surrounding communities. Still, there is public concern over the possible amount and magnitude of the seismicity associated with current and future EGS operations. It is pointed out that microseismicity has been successfully dealt with in a variety of non-geothermal as well as geothermal environments. Several case histories are also presented to illustrate a variety of technical and public acceptance issues. It is concluded that EGS Induced seismicity need not pose any threat to the development of geothermal resources if community issues are properly handled. In fact, induced seismicity provides benefits because it can be used as a monitoring tool to understand the effectiveness of the EGS operations and shed light on the mechanics of the reservoir

Constraining temperature at depth of the Kakkonda geothermal field, Japan, using Bayesian rock-physics modelling of resistivity: Implications to the deep hydrothermal system

Temperature-at-depth estimation is important for assessing supercritical geothermal resources. Bayesian rock-physics modelling of electrical resistivity is effective for estimating temperatures at depth. In this study, we improved a previously proposed Bayesian framework and demonstrated its effectiveness by estimating subsurface temperatures in the Kakkonda geothermal field, Japan. The proposed framework allows the estimation of either effective porosities or salinities in addition to temperatures; further, we were able to constrain the possible states of the crustal fluid at depth based on the estimates. The estimated 3D temperature structure was consistent with available deep temperature logs. Furthermore, the estimated results suggest the existence of a magmatic-hydrothermal system at depth in the field