Comparison of clinical pictures of mitochondrial encephalomyopathy with tRNA(Leu(UUR)) mutation in 3243 with that in 3254]

We compared clinical pictures of a case of mitochondrial encephalomyopathy with tRNA(Leu(UUR)) point mutation at nucleotide position 3254 of mitochondrial DNA with those at position 3243. The mutation 3254 was a 19-year-old male patient with cardiomyopathy accompanied with muscle atrophy. The first mutant 3243 was a 31-year-old female patient showing clinical features of MELAS and endocrinological abnormalities. The second 3243 mutant was a 27-year-old male patient who had an external ophthalmoplegia and slight mental decline. In all cases, muscle biopsy specimen showed ragged red fibers and strongly SDH-reactive blood vessels, but their limb weakness were unremarkable. These results suggest that tRNA(Leu(UUR)) point mutation 3254 exhibits similar clinical phenotypes as those observed in 3243 mutant.     

Increased serum vascular endothelial growth factor levels and intrathyroidal vascular area in patients with Graves' disease and Hashimoto's thyroiditis

Vascular endothelial growth factor (VEGF) is one of the angiogenic factors. We examined both thyroid volume and intrathyroidal vascular area by color flow Doppler ultrasonography in patients with Graves' disease (GD), Hashimoto's thyroiditis (HT), and subacute thyroiditis. The serum concentrations of thyroid hormones, TSH, TSH receptor antibodies, and VEGF were also examined. There was a significant increase in serum VEGF levels in patients with untreated GD and goitrous HT compared with those in healthy subjects. The serum VEGF levels in untreated patients with subacute thyroiditis were significantly higher than those in patients with untreated GD or HT. There was a significant correlation between serum VEGF levels and the ratio of intrathyroidal vascular area and thyroid area in untreated patients with GD who had a goiter larger than or equal to 40 cm3. There was also a significant correlation between serum VEGF and TSH levels in patients with HT who were hypothyroid and had a goiter. Serum VEGF levels decreased significantly in these patients after treatment; this was accompanied by a significant decrease in intrathyroidal vascular area and thyroid volume. Our study demonstrates that VEGF appears to play an important role in intrathyroidal angiogenesis in patients with GD and goitrous HT.     

Daily wheel running activity modifies the period of free-running rhythm in rats via intergeniculate leaflet

The period of free-running rhythms (tau) in rats, as measured using a running wheel, is different from that measured using an Automex. The aim of this work was to examine the effects of lesions of the intergeniculate leaflet (IGL) on the tau of these two activity rhythms. When blind rats were transferred from a cage with a running wheel to a cage without a running wheel, the tau lengthened. The tau of the wheel-running activity was associated with the number of wheel revolutions per day. A complete lesion of the IGL lengthened the tau of the wheel-running activity, and caused a reduction in the number of wheel revolutions per day in all rats. In rats housed in cages without a running wheel, locomotor activity was reduced by IGL lesions, although the tau was unaffected. When IGL-lesioned rats were transferred from a cage with a running wheel to a cage without a running wheel, no further change was observed. These results indicate that the tau is modified by the daily activity of wheel-running, but not by general locomotor activity, and that the IGL may be involved in this modification.     

Alterations in glutathione peroxidase activity following reperfusion injury to rat liver

Prevention of cellular damage after warm ischemia is of major importance in liver transplantation. In this study, we determined the extent to which lipid peroxides contribute to the pathogenesis of hepatic cell damage induced by transient warm ischemia with subsequent reperfusion. In addition, the function and immunohistochemical features of glutathione peroxidase, a potent physiological lipid peroxide scavenger of the liver, was assessed. Reperfusion following 15 or 30 minutes of warm ischemia resulted in a significant elevation in serum and liver lipid peroxidase (LPO) levels. In addition, necrosis of the hepatic periportal area accompanied with remarkable rises in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were observed. In contrast, 30 min of ischemia without reperfusion caused minimal hepatocellular damage. The adverse changes after ischemia/reperfusion were minimized by pretreatment with superoxide dismutase (SOD). These results indicate that increased lipid peroxidation by production of radicals after reperfusion caused the liver cell damage. After ischemia/reperfusion, liver glutathione peroxidase (GSH-PO) activity was significantly decreased and its location altered in the damaged liver. These findings suggest that GSH-PO contributes significantly to the protection against hepatic reperfusion injuries.     

The design of deadbeat controllers by state transition graph

Two kinds of deadbeat control problems are considered. One is the state deadbeat control problem and the other is the pointwise minimum-time deadbeat control problem. A simple graph called the state transition graph of a matrix is introduced, and simple algorithms based on it giving deadbeat controllers are presented. The set of pointwise minimum-time deadbeat controllers is characterized. The set of output feedback deadbeat controller is also considered     

Pole assignment by state transition graph

The pole assignment problem is considered, using the graph representation of a matrix. The parametrization of controllers which have a specified characteristic polynomial is given. A simple algorithm based on graphs is presented and two examples are given     

Application study of a high‐temperature superconducting fault current limiter for electric power system

Using high‐temperature superconductors, a superconducting fault current limiter (SFCL) was fabricated and tested. The superconductor and a vacuum interrupter serving as a commutation switch were connected in parallel with a bypass coil. When a fault occurs and excessive current flows, the superconductor is first quenched and the current is transferred to the bypass coil because of the voltage drop of the superconductor. At the same time, since a magnetic field is generated by the current flowing in the bypass coil, the commutation switch is immediately driven by an electromagnetic repulsion plate connected to the driving rod of the vacuum interrupter (VI), and the superconductor is separated from this circuit. Using the test model, we were able to separate the superconductor from the circuit by the movement of the VI within a half current cycle and to transfer all current to the bypass coil. Since the operation of the commutation switch is included in the current limiting operation of this test model, it will be a useful circuit in the development of SFCL in the future. Moreover, since it can make the energy consumption of the superconductor small during the fault state due to the realization of a high‐speed switch with simple composition, the burden on the superconductor is reduced compared with the conventional resistive type of SFCL and it is considered that the flexibility of SFCL design is increased. Cooperation with a circuit breaker was also considered; trial calculations of the parameters and energy of operation were conducted and a discussion of the installation of the SFCL in an electric power system is presented. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(4): 20–29, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20265