Roles of ET-1 in endotoxin-induced microcirculatory disturbance in rat small intestine

1996 ◽  
Vol 271 (3) ◽  
pp. G461-G469 ◽  
Author(s):  
S. Miura ◽  
D. Fukumura ◽  
I. Kurose ◽  
H. Higuchi ◽  
H. Kimura ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Intestinal Mucosa ◽  
High Speed ◽  
Platelet Activating Factor ◽  
Video Camera ◽  
Mucosal Damage ◽  
Dependent Manner ◽  
Camera System ◽  
Eta Receptor Antagonist ◽  
Leukocyte Sticking

The major objective of this study was to investigate whether endothelin-1 (ET-1) plays a significant role in endotoxin-induced microcirculatory disturbances of the intestinal mucosa. Submucosal microvessels of the rat ileum were observed by intravital microscopy with a high-speed video camera system. Preceding the apparent intestinal mucosal damage, red blood cell (RBC) velocity was significantly decreased 30 min after endotoxin treatment in both arterioles and venules. The number of leukocytes sticking to submucosal venules was significantly increased at 30 min. BQ-123, an ETA-receptor antagonist, significantly attenuated the decrease in RBC velocity and also prevented an increase in leukocyte sticking as well as the subsequent mucosal damage induced by endotoxin. The ET-1 concentrations began to be elevated in plasma at 15 min and in the mucosa at 30 min and subsequently further increased in a time-dependent manner. A significant decrease in calcium-dependent nitric oxide synthase activity and significant increases in the concentration of platelet-activating factor (PAF) were demonstrated in the intestinal mucosa after endotoxin treatment. BQ-123 also significantly attenuated these changes. We concluded that the increased ET-1 production in intestinal mucosa induced by endotoxin stimulation could lead to leukocyte sticking and decreased RBC velocity in the intestinal microcirculatory beds via ETA receptors, which are closely related to increased production of PAF and decreased synthesis of constitutive nitric oxide.

Attenuation of endotoxin-induced intestinal microcirculatory damage by eicosapentanoic acid

1993 ◽  
Vol 264 (5) ◽  
pp. G828-G834 ◽  
Author(s):  
S. Miura ◽  
H. Imaeda ◽  
H. Shiozaki ◽  
I. Kurose ◽  
D. Fukumura ◽  
...  
Keyword(s):  
High Speed ◽  
Platelet Activating Factor ◽  
Video Camera ◽  
Ileal Mucosa ◽  
Camera System ◽  
Endotoxin Infusion ◽  
Eicosapentanoic Acid ◽  
High Speed Video Camera ◽  
Male Wistar Rats ◽  
Video Camera System

The major objective of this study is to investigate whether oral administration of eicosapentanoic acid (EPA) has any preventive effect on endotoxin-induced microcirculatory damage of rat small intestine. EPA in a daily dose of 300 mg/kg was orally given to male Wistar rats for 3 wk. Submucosal microvessels of the ileum were observed by intravital microscopy equipped with a high-speed video camera system after the intra-arterial infusion of endotoxin at a dose of 2 mg.kg-1.h-1. The number of sticking leukocytes was significantly increased at 30 min after the treatment of endotoxin especially along the smaller branch of intestinal venules. It reached the maximal plateau at 45 min after treatment. The pretreatment of EPA significantly attenuated the increase in sticking leukocytes induced by endotoxin. A platelet-activating factor (PAF) antagonist 2-[N-acetyl-N-(2-methoxy-3-octadecylcarbamoyloxy propoxycarbonyl) aminomethyl]-1-ethylpyridinium chloride (CV-6209) significantly prevented the increased leukocyte sticking to the same extent as EPA treatment. Thirty minutes after endotoxin infusion, red blood cell (RBC) velocity was significantly decreased in both arterioles and venules. RBC velocity appeared to be continuously decreased thereafter and reached its minimum value at approximately 60 min. EPA treatment was revealed to prevent the decrease in RBC velocity of microvessels induced by endotoxin. CV-6209 also significantly attenuated the decreased RBC velocity. The remarkable elevation of PAF content in the ileal mucosa as observed by endotoxin infusion was also significantly attenuated by administration of EPA.(ABSTRACT TRUNCATED AT 250 WORDS)

Structural Dynamics and Response of Roof Tiles Under Wind Loading: Effect of Vibration on Scattering

2007 ◽  
Author(s):  
S. Okamoto
Keyword(s):  
High Speed ◽  
Coherence Function ◽  
Slope Angle ◽  
Video Camera ◽  
Frequency Mode ◽  
Wind Loading ◽  
Camera System ◽  
High Speed Video ◽  
High Speed Video Camera ◽  
Lower Frequency Mode

This study has investigated the nature and source of the vibrating and scattering behavior of roof tiles with the aim of providing a better insight to the mechanism. The 100 roof tiles were set up on 10 lines and 10 lows on the pitched roof in the downstream of the flow from the wind tunnel. These experiments were followed by series of tests where the slope angle of the roof tiles was changed. The vibrations of the roof tiles were simultaneously measured by the two accelerometers, and the motions of the vibration and scattering were observed by the high-speed video camera. The frequency response function and coherence function of roof tile were measured by impact hammer test under no flow condition. Just before scattering of the roof tiles, both vibrations of higher frequency mode and vibrations of lower frequency mode appeared simultaneously in roof tiles. The values of the higher frequencies were corresponding to the values of resonant frequencies of the roof tiles. It was thought that the scattering of roof tiles was influenced by the vibration of the lower frequency mode. The frequencies of the vibration were measured by the high-speed video camera system. The values of the lower frequencies were 10 Hz ∼ 20 Hz. The mechanism of scattering of roof tiles could be understood by means of the information from the accelerations and the images of roof tiles.

Dynamic Interfacial Phenomena at Water-Magnetic Fluid System Subject to Alternating Magnetic Field

2016 ◽  
Vol 856 ◽  
pp. 15-20
Author(s):  
Masato Nakanishi ◽  
Seiichi Sudo ◽  
Hideya Nishiyama
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Magnetic Fluid ◽  
High Speed ◽  
Video Camera ◽  
Alternating Magnetic Field ◽  
Fluid System ◽  
Camera System ◽  
High Speed Video Camera ◽  
Rosensweig Instability

Responses of a magnetic fluid interface adsorbed on a small permanent magnet in water container subjected to an alternating magnetic field were studied with a high-speed video camera system. The directions of the external alternating magnetic field were parallel and anti-parallel to that of the permanent magnet. It was found that the interface of water-magnetic fluid responds to the external alternating magnetic field in elongation and contraction with Rosensweig instability at the interface. Frequency characteristics of the interface response of water-magnetic fluid system subjected to alternating magnetic field were revealed over a wide frequency band experimentally.

Vibration Characteristics of Magnetic Fluid Droplet Adsorbed to Magnetized Needlepoint in Alternating Magnetic Field

2012 ◽  
Vol 721 ◽  
pp. 108-113
Author(s):  
Sota Inomata ◽  
Seiichi Sudo ◽  
Hidemasa Takana ◽  
Hideya Nishiyama
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fluid ◽  
High Speed ◽  
Video Camera ◽  
Alternating Magnetic Field ◽  
Camera System ◽  
High Speed Video ◽  
High Speed Video Camera ◽  
Video Camera System

The dynamic behavior of a magnetic fluid droplet adsorbed to magnetized needlepoint in alternating magnetic field was studied with a high speed video camera system. The directions of alternating magnetic field were parallel and opposite to static magnetic field of magnetized needlepoint. It was found that the surface of magnetic fluid droplet responds to the external magnetic field in elongation and contraction. The frequency of magnetic fluid droplet oscillation was exactly same of the external magnetic field. The shape and instability oscillations of the magnetic fluid droplet were revealed experimentally.

Two-Phase Slug Flow in a Narrow Rectangular Channel Under Inclined Conditions

2014 ◽  
Author(s):  
Yang Wang ◽  
Changqi Yan ◽  
Licheng Sun ◽  
Chaoxing Yan ◽  
Yanmin Zhou ◽  
...  
Keyword(s):  
Slug Flow ◽  
High Speed ◽  
Rectangular Channel ◽  
Video Camera ◽  
Superficial Velocity ◽  
Bubble Velocity ◽  
Two Phase ◽  
Camera System ◽  
Taylor Bubble ◽  
Inclination Angles

The characteristics of two-phase slug flow in a narrow rectangular channel with cross section of 3.25 mm × 43 mm under vertical and inclined conditions are investigated using a high speed video camera system. It is found that the velocity of Taylor bubble in vertical continuous slug flow could be well predicted by the Nicklin et al. (1962) correlation, in which C0 is given by the correlation of Ishii (1977), and the drift velocity given by the correlation of Sadatomi et al. (1982) or Clanet et al. (2004). For low two-phase superficial velocity (FrTP ≤ 3.5), the Taylor bubble velocities gradually increase with the increasing in inclination angles and almost approximate the maximum value for θ = 30°. For high two-phase superficial velocity (FrTP > 3.5), the influence of the inclination angles on the Taylor bubble velocity is insignificant, and the bubble velocity under vertical condition is slight lower than those under inclined conditions. For the inclined cases, the nose of Taylor bubble is deviated from the centerline and its position is the function of the two-phase superficial velocity as well as the inclination angle.

Precise color images a high-speed color video camera system with three intensified sensors

1999 ◽  
Author(s):  
Sachio Oki ◽  
Masafumi Yamakawa ◽  
Susumu Gohda ◽  
Takeharu G. Etoh
Keyword(s):  
High Speed ◽  
Video Camera ◽  
Color Images ◽  
Camera System ◽  
Color Video ◽  
Video Camera System
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