The relationship of gastric hypermotility to mucosal hemodynamics, lipid peroxidation and vascular permeability changes was investigated in the pathogenesis of indomethacin-induced gastric lesions in rats. Subcutaneous administration of indomethacin (25 mg/kg) produced an increase in both the amplitude and frequency of stomach contraction from 30 min after treatment, resulting in hemorrhagic damage 2 h later. Gastric mucosal blood flow measured by a Laser flowmetry showed oscillatory fluctuations under hypercontractile states: a decrease during contraction followed by an increase during relaxation. Mucosal lipid peroxidation and vascular permeability were significantly increased with time after indomethacin treatment, and these changes preceded the appearance of hemorrhagic damage. All these events were prevented when gastric hypermotility was inhibited by atropine or 16,16-dimethyl prostaglandin E2. Pretreatment of the animals with allopurinol and hydroxyurea or continuous infusion of superoxide dismutase and dimethyl sulfoxide during a test period also attenuated these functional changes and mucosal lesions induced by indomethacin, without affecting the motility response. We conclude that oxygen free radicals may play a role in the development of mucosal lesions associated with gastric hypermotility in indomethacin-treated rats.
SUMMARYThe purpose of this study was to investigate the cellular distribution of carnitine and its acyl derivatives in the normal and ischemic myocardium, and the effects of exogenous l-carnitine on this distribution and mitochondrial function in the ischemic dog heart. Under nonischemic conditions, about 93% of the total cellular carnitine was located in the cytosolic compartment and 6.5% in the mitochondrial compartment. Sixty minutes of ischemia induced a decrease in the cytosolic free carnitine content, but caused the accumulation of long-chain acylcarnitine in the cytosolic and mitochondrial compartments.Treatment with l-carnitine (30 or 100mg/kg, i.v.) inhibited the mitochondrial accumulation of long-chain acylcarnitine. Free fatty acid (FFA) metabolism in the mitochondria differs from that in the cytosol. So, it is necessary to investigate the changes in FFA metabolism in both of these cellular compartments. Our results suggest that l-carnitine has a protective effect on the ischemic heart by selectively reducing mitochondrial accumulation of long-chain acylcarnitine.
This paper describes a prototype design and preliminary evaluation of a decentralized modular device network for wide-area monitoring, protection and control of power systems, utilizing off-the-shelf and standardized information and communications technologies (ICT). The prototype network consists of 100M/1Gbps L2 switch networks, device-embedded and external IEEE 1588-based time synchronizing schemes, and function-and application-based modular devices. Experimental results show that a time synchronization error of less than 1 microsecond between modular devices was achieved, and that the versatile implementation of applications such as wide-area current differential protection and state measurements was conducted successfully.future power system communication environments and fully IP-or Ethernet-based networks in mind.The authors examined the applicability of IP-related technologies to existing teleprotection systems utilizing PDH (Presiochronous Digital Hierarchy) technologies to show the needs of communication interface converters with modest delay and delay skew or the modification of embedded communication interfaces in protection relays in order to meet their stringent communication requirements [3]. Another option would be to develop a completely different concept of wide-area protection and control systems to meet the future requirements mentioned above.This paper proposes the concept of a modular device network enabling wide-area monitoring, protection and control associated with wide-area Ethernet, precise time synchronization and modular IED (Intelligent Electronic Device). First highlighted is the concept of the networks, followed by their prototype design. Finally, preliminary examination of the prototype is provided with respect to time synchronization errors and application system versatility.
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