Pathogenic role of glutamate in hyperthermia-induced seizures

Hyperthermia induces seizures in both humans and rodents, but the underlying mechanism remains unknown. The present study showed that hyperthermia, causing rapid increase in body temperature, increases the concentration of glutamate (Glu) released into a cortical perfusate before onset of seizures in rats and that this increase in Glu concentration correlated with a decrease in seizure threshold temperature. These results indicate that increased cortical extracellular Glu induced by hyperthermia contributes to onset of seizures. The same mechanism may be involved in clinical seizures induced by fever in patients with febrile convulsions or epilepsy.     

Distribution of SP- and CGRP-immunoreactivity in the cat's larynx

The distribution of substance P (SP) and calcitonin gene-related peptide (CGRP) immunoreactive (ir) fibres in the cat's larynx was investigated utilizing immunohistochemistry. Many SP- and CGRP-ir fibres with varicosities were found within and below the epithelium and along the basement membrane of the mucosa of all different regions except in the membranous portion of the vocal fold. In the subepithelium, some SP- and CGRP-ir nerve bundles and nerve fibres were recognized around the vessels and glands. In the mucosa, the pattern of distribution and the density of SR-ir fibres were similar to those of CGRP-ir fibres. These reactive fibres were denser in the supraglottic region than in the subglottic region. In the taste bud-like structures, only SP-ir fibres appeared, whereas in the motor endplates, CGRP-reaction was found exclusively. The present findings suggest that the regional distribution of SP- and CGRP-immunoreactivity might be related with sensory and autonomic innervation in the larynx.     

KB-R7785, a novel matrix metalloproteinase inhibitor, exerts its antidiabetic effect by inhibiting tumor necrosis factor-alpha production

It has been suggested that tumor necrosis factor-alpha (TNF-alpha) is a key mediator of insulin resistance in non-insulin-dependent diabetes mellitus (NIDDM). TNF-alpha is synthesized as a membrane-bound precursor; this is proteolytically processed to an active form by a matrix metalloproteinase (MMP)-like enzyme. In this study, we have used KKAy mice which show insulin resistance like NIDDM to investigate the effects of KB-R7785, a novel MMP inhibitor, on blood glucose and insulin levels. Subcutaneous administration of KB-R7785 at 100 mg/kg twice daily (i.e., 200 mg/kg/day) for 4 weeks resulted in a significant decrease in plasma glucose levels which was observed after 3 weeks. Oral administration of pioglitazone (20 mg/kg twice daily or 40 mg/kg/day for 4 weeks), an agent known to ameliorate insulin sensitivity, significantly decreased plasma glucose levels during the treatment period. KB-R7785, but not pioglitazone, also significantly decreased plasma insulin levels. Lipopolysaccharide (LPS) increased plasma TNF-alpha levels to a significantly greater degree in KKAy mice than in normal C57BL mice; this was inhibitable in KKAy mice by KB-R7785. In contrast, pioglitazone did not affect the LPS-induced increase in plasma TNF-alpha levels in KKAy mice. These results suggest that KB-R7785 exerts its antidiabetic effect by ameliorating insulin sensitivity through the inhibition of TNF-alpha production.     

Different secretion patterns of adrenomedullin, brain natriuretic peptide, and atrial natriuretic peptide during exercise in hypertensive and normotensive subjects

The purpose of this study was to investigate the effect of exercise on plasma concentrations of adrenomedullin, brain natriuretic peptide (BNP), and atrial natriuretic peptide (ANP) in patients with essential hypertension (n = 15) and in normotensive controls (n = 10). Exercise consisted of two fixed workloads, 40 and 80 watts of work load using a supine bicycle ergometer. Plasma levels of all three peptides at rest were significantly higher in hypertensives than in controls. Plasma concentrations of ANP increased with exercise in both groups and had greater increments in hypertensive patients than in normotensives. Plasma concentrations of BNP increased only in patients with hypertension and the levels of increase correlated with basal plasma BNP levels (r = 0.94, p < 0.001) and with left ventricular mass (r = 0.62, p < 0.01) determined by echocardiography. In contrast, plasma adrenomedullin did not change with exercise in either group. These results suggest that secretion patterns of these peptides are regulated by different mechanisms and that the amount and kind of peptides mobilized by exercise may depend on the underlying diseases or pathophysiologic condition.     

New power consolidation-inversion-control system for faraday MHD generator

The authors propose a new power consolidation-inversion-control system for the Faraday MHD generator using the voltage source PWM inverters. The dc output power for each electrodes pair of the MHD generator is at first inverted into three-phase ac power by a voltage source PWM inverter, and then the ac powers are consolidated by transformers. The proposed system does not need such expensive equipment as an ac filter or phase modifier and can independently and simultaneously control the active and reactive powers provided to the electric power system. Numerical simulations of the whole system, including the Faraday MHD generator, the proposed power consolidation-inversion-control system, and the electric power system, show that the proposed system can stably and steadily transmit and control the electric power from the MHD generator to the electric power system. It is also confirmed that the proposed system can independently and simultaneously control the active and reactive powers and can be used as a fast power controller.     

An experimental study of conductive heating using a concentric double-electrode applicator

With hyperthermia for treatment of superficial tumors in mind, a prototype applicator with two electrodes arranged concentrically on a disk was designed for efficient local heating, and a basic heating test was carried out. Frequencies as low as 200 kHz were used in order to simplify the configuration of the power device. The applicator consists of two electrodes, a circular inner electrode and another looped outer electrode, arranged concentrically. Water was passed through the applicator as a cooling mechanism; it was placed in direct contact with the target tissue to be heated and then charged with electricity. In the heating test using a phantom, oval hot spots were noted below the inner electrode. Using cooling water at 3 degrees C and 8.2 W, an isothermal line of 45 degrees C was located at a 5-mm radius circle around the central axis with 9 mm depth. A similar temperature distribution map was obtained in heating tests on the thigh muscle of a mongrel adult dog. The temperature distribution maps obtained from these tests corresponded closely with the results of theoretical analysis carried out according to the finite-element method. Since a comparatively low frequency was employed for this applicator the power device was simplified, which made adequate heating possible with low electric power. The temperature distribution map indicated that efficient local heating of superficial tumors could be achieved.     

Speed control system and design of resonant system with disturbance observer

In industrial motor drive systems such as industrial plants and industrial robots, a torsional vibration often is generated because of the elastic elements in torque transmission. This vibration makes it difficult to achieve quick responses of speed and may result in damage to the plant. Such systems simply are modeled as a two mass system. The shaft torque feedback system with the disturbance observer, which is called “resonance ratio control,” is proposed to suppress the vibration for the two-mass system. In this paper, the design of controller gains in the shaft torque feedback system is examined considering not only the control performance such as the vibration suppression and dynamic responses, but also the robust stability against the noise and the model uncertainties. This paper shows the validity of the control system and the examinations by several experiments.     

Regulation of albumin mRNA and its promoter-binding nuclear factors under different perioperative nutritional methods in hepatectomized rats

BACKGROUND: Regulation of perioperative albumin synthesis under parenteral (PN) and enteral (EN) nutrition was investigated. METHODS: Rats were divided into PN and EN groups. Both groups received the same regimen of artificial nutrition for 7 days and then underwent 70% hepatectomy. Serum albumin and mRNA levels of albumin and its promoter-binding nuclear factors (C/EBPalpha, beta, and DBP) were measured. RESULTS: Serum albumin and albumin mRNA in the PN group were significantly lower than those in the EN group at 72 hours after hepatectomy. Preoperative and postoperative DBP and C/EBPalpha mRNA levels in the EN group were significantly higher than those in the PN group. CONCLUSION: Serum albumin was well maintained by EN after hepatectomy owing to an early recovery of albumin mRNA level and its nuclear factor mRNA levels (C/EBPalpha and DBP). Compared with PN, EN is a more advantageous from of perioperative nutrition as pertains to albumin synthesis.     

The use of free rectus abdominis myocutaneous flap to close the empyema space with alveolar fistula--a case report

A 59-year-old man, who had had right middle and lower lobectomy for pulmonary tuberculosis, admitted for the treatment of empyema with fistula. Closure of empyema space with free rectus abdominis myocutaneous flap was performed following open window thoracotomy and thoracoplasty. As he previously underwent two major operation, lobectomy by posterolateral approach and gastrectomy for gastric ulcer, free rectus abdominis flap was chosen instead of omental flap or latissimus dorsi myocutaneous flap. Postoperative CT film showed that this flap was filled up in all interstices of the empyema cavity. The pedicle vessels to this flap are large enough to provide long stalks, so microsurgical anastomosis can be accomplished safely. The use of free rectus abdominis myocutaneous flap is one of a useful maneuver for chronic empyema with fistula.