Effects of an AT1 receptor antagonist, an ACE inhibitor and a calcium channel antagonist on cardiac gene expressions in hypertensive rats

1. This study was undertaken to determine whether the AT1 receptor directly contributes to hypertension-induced cardiac hypertrophy and gene expressions. 2. Stroke-prone spontaneously hypertensive rats (SHRSP) were given orally an AT1, receptor antagonist (losartan, 30 mg kg-1 day-1), an angiotensin converting enzyme inhibitor (enalapril 10 mg kg-1 day-1), a dihydropyridine calcium channel antagonist (amlodipine, 5 mg kg-1 day-1), or vehicle (control), for 8 weeks (from 16 to 24 weeks of age). The effects of each drug were compared on ventricular weight and mRNA levels for myocardial phenotype- and fibrosis-related genes. 3. Left ventricular hypertrophy of SHRSP was accompanied by the increase in mRNA levels for two foetal phenotypes of contractile proteins (skeletal alpha-actin and beta-myosin heavy chain (beta-MHC)), atrial natriuretic polypeptide (ANP), transforming growth factor-beta-1 (TGF-beta 1) and collagen, and a decrease in mRNA levels for an adult phenotype of contractile protein (alpha-MHC). Thus, the left ventricle of SHRSP was characterized by myocardial transition from an adult to a foetal phenotype and interstitial fibrosis at the molecular level. 4. Although losartan, enalapril and amlodipine lowered blood pressure of SHRSP to a comparable degree throughout the treatment, losartan caused regression of left ventricular hypertrophy of SHRSP to a greater extent than amlodipine (P < 0.01). 5. Losartan significantly decreased mRNA levels for skeletal alpha-actin, ANP, TGF-beta 1 and collagen types I, III and IV and increased alpha-MHC mRNA in the left ventricle of SHRSP. Amlodipine did not alter left ventricular ANP, alpha-MHC and collagen types I and IV mRNA levels of SHRSP. 6. The effects of enalapril on left ventricular hypertrophy and gene expressions of SHRSP were similar to those of losartan, except for the lack of inhibition of collagen type I expression by enalapril. 7. Unlike the hypertrophied left ventricle, there was no significant difference between losartan and amlodipine in the effects on non-hypertrophied right ventricular gene expressions of SHRSP. 8. Our results show that hypertension causes not only left ventricular hypertrophy but also molecular transition of myocardium to a foetal phenotype and interstitial fibrosis-related molecular changes. These hypertension-induced left ventricular molecular changes may be at least in part mediated by the direct action of local angiotensin II via the AT1, receptor.     

Rapid expression and specific localization of tenascin in gastric ulcer healing in rats

This study was done to investigate the gene expression and localization of tenascin in ulcerated gastric tissues during the healing process with Northern blot analysis and immunohistochemical technique. Gastric ulcers in rats were produced by acetic acid. Tenascin mRNA levels in the ulcerated tissue were significantly increased in a biphasic manner (12 h and day 5), preceding the increase in collagen type IV and laminin mRNA levels, and returned to control levels on day 11. In intact tissues, tenascin was mainly localized in the basement membrane above the proliferative zone, in contrast to the predominant localization of collagen type IV and laminin below the proliferative zone. On the ulcer margin from 12 h to day 5, tenascin was abundantly observed in the lamina propria around nonproliferating new epithelial cells, but collagen type IV and laminin were not seen in this lamina propria. On day 7, tenascin, expressed in the lamina propria, was replaced by collagen type IV and laminin. Thus, the rapid expression and unique localization of tenascin suggest the important role of tenascin in gastric ulcer healing.     

Mechanical strength of fusion-spliced optical fibres

Mechanical strengths of optical fibres heated under different electric-discharge conditions have been systematically examined. Exclusion of fibre surface contaminations and making heating duration as short as possible are important for prevention of strength deterioration.     

A flexible OLED display with an OTFT backplane made by scalable manufacturing process

Abstract— A full‐color top‐emission AMOLED display driven by an organic TFT backplane manufactured using a scalable, lift‐off‐free, and shadow‐mask‐free process has been developed. It was shown that cost‐efficient copper can be used for S/D electrodes. The display has shown no significant degradation over a storage life of more than 10 months and operation over 25 hours during which the display is bent over 10,000 times.     

Flow characteristics of plunging flows in steep sloping channels with a horizontal channel portion

This paper presents the effect of an aerated inflow on flow conditions of a plunging flow region in steep sloping channels (30 and 55°) with a horizontal channel portion. The flow condition of the plunging flow region and the reverse flow length are affected by the depth averaged air-concentration ratio of the aerated inflow. For a fully aerated inflow with a large downstream depth, a high velocity jet decays in a short distance, and a hydraulic jump is formed on the sloping channel portion. However, for a non-aerated inflow with a large downstream depth, a high velocity jet continues far downstream as a wall jet. The effect of aerated inflow on the velocity field in the plunging flow region has been shown.     

Chemical sensing plate with a laser-terahertz monitoring system

A new type of laser-terahertz emission system for noncontact investigations of chemical solutions has been developed. The system monitors terahertz emission from a sensing plate, which consists of silicon oxide and silicon thin film layers on a sapphire substrate. Sensing of chemical solutions with pH values between 1.68 and 10.01 was demonstrated. The amplitude of the terahertz emission from the sensing plate increased with increasing pH value. This change in the amplitude was caused by a change in the depletion layers of the silicon thin film when protons were adsorbed on the surface of the sensing plate. This study demonstrates that full noncontact monitoring of chemical solutions is possible using the laser-terahertz emission system.     

Structures and vapor-sorption characteristics of sputtered polychlorotrifluoroethylene films treated by hydrogen-plasma

Hydrogen-plasma treatment of the polychlorotrifluoroethylene (PCTFE) film produced by radio-frequency sputtering induces considerable elimination of halogen (fluorine and chlorine) atoms. This dehalogenation produces some noteworthy structural features: surface densification (crosslinks), trapped radicals, and incorporation of oxygen in the carbon networks. These structural changes modify the vapor-sorption properties of the sputtered PCTFE film, producing a molecular-sieving effect and enhancing the polar character of solubility properties of organic vapors.     

Discriminative detection of volatile sulfur compound mixtures with a plasma-polymerized film-based sensor array installed in a humidity-control system

We demonstrated the discrimination of volatile sulfur compound mixtures with different mixing ratios by using an array of the plasma-polymerized film (PPF)-coated quartz crystal resonators. The PPF sensor array, which contains PPFs prepared from amino acids and synthetic polymers, exhibited different response patterns to mono or mixed volatile sulfur compounds (VSCs) (hydrogen sulfide and methanethiol) under a dry environment. The sensor array was installed in a desktop-size relative humidity controller. The relative humidity and temperature conditions of the sample flow to the sensor cell were equalized to those of the inner atmosphere of the sensor cell based on the concept of the two-separate-temperatures method. In this way, the baseline drift of PPF sensor response caused by the introduction of a highly humid sample was successfully suppressed. We compared the sensor array responses under the controlled humidity conditions. Presorption of water molecules by PPFs caused a decrease of sensor sensitivity, but the films still had the ability to discriminate sub-ppmv VSC mixtures having 6:1, 1:1, and 1:6 mixture ratios of hydrogen sulfide and methanethiol.