Role of Gap Junctions in the Endothelium-Dependent Hyperpolarization of Vascular Smooth Muscle Cells

Yoshimichi Yamamoto,Megan F. Klemm,Hikaru Hashitani,Richard J. Lang,Tsuyoshi Soji.,Hikaru Suzuki 대한생리학회-대한약리학회 2001 The Korean Journal of Physiology & Pharmacology Vol.5 No.1

<P> Hyperpolarization of arterial smooth muscle by acetylcholine is considered to be produced by the release of an unidentified chemical substance, an endothelium-derived hyperpolarizing factor (EDHF). Several chemicals have been proposed as the candidate for EDHF. However, none of them fulfil completely the nature and property of EDHF. Ultrastructural observation with electron microscope reveals that in some arteries, gap junctions are formed between endothelial and smooth muscle cells. In small arterioles, injection of gap junction permeable dyes into an endothelial cell results in a distribution of the dye to surrounding cells including smooth muscle cells. These observations allow the speculation that myoendothelial gap junctions may have a functional significance. Simultaneous measurement of the electrical responses in both endothelial and smooth muscle cells using the double patch clamp method demonstrates that these two cell types are indeed electrically coupled, indicating that they behave as a functional syncytium. The EDHF-induced hyperpolarization is produced by an activation of Ca<SUP>2⁢</SUP>-sensitive K<SUP>⁢</SUP>-channels that are inhibited by charybdotoxin and apamin. Agonists that release EDHF increase [Ca<SUP>2⁢</SUP>]<SUB>i</SUB> in endothelial cells but not in smooth muscle cells. Inhibition of gap junctions with chemical agents abolishes the agonist- induced hyperpolarization in smooth muscle cells but not in endothelial cells. All these observations can be explained if EDHF is an electrotonic signal propagating from endothelium to smooth muscle cells through gap junctions.

Single-particle characterization of aerosols collected at a remote site in the Amazonian rainforest and an urban site in Manaus, Brazil

Wu, Li,Li, Xue,Kim, HyeKyeong,Geng, Hong,Godoi, Ricardo H. M.,Barbosa, Cybelli G. G.,Godoi, Ana F. L.,Yamamoto, Carlos I.,de Souza, Rodrigo A. F.,Pö,hlker, Christopher,Andreae, Meinrat O.,Ro, Chul Copernicus GmbH 2019 Atmospheric chemistry and physics Vol.19 No.2

<P><p><strong>Abstract.</strong> <span id='page1222'/>In this study, aerosol samples collected at a remote site in the Amazonian rainforest and an urban site in Manaus, Brazil, were investigated on a single-particle basis using a quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA). A total of 23 aerosol samples were collected in four size ranges (0.25-0.5, 0.5-1.0, 1.0-2.0, and 2.0-4.0<span class='thinspace'></span><span class='inline-formula'>µ</span>m) during the wet season in 2012 at two Amazon basin sites: 10 samples in Manaus, an urban area; and 13 samples at an 80<span class='thinspace'></span>m high tower, located at the Amazon Tall Tower Observatory (ATTO) site in the middle of the rainforest, 150<span class='thinspace'></span>km northeast of Manaus. The aerosol particles were classified into nine particle types based on the morphology on the secondary electron images (SEIs) together with the elemental concentrations of 3162 individual particles: (i) secondary organic aerosols (SOA); (ii) ammonium sulfate (AS); (iii) SOA and AS mixtures; (iv) aged mineral dust; (v) reacted sea salts; (vi) primary biological aerosol (PBA); (vii) carbon-rich or elemental carbon (EC) particles, such as soot, tarball, and char; (viii) fly ash; and (ix) heavy metal (HM, such as Fe, Zn, Ni, and Ti)-containing particles. In submicron aerosols collected at the ATTO site, SOA and AS mixture particles were predominant (50<span class='thinspace'></span>%-94<span class='thinspace'></span>% in relative abundance) with SOA and ammonium sulfate comprising 73<span class='thinspace'></span>%-100<span class='thinspace'></span>%. In supermicron aerosols at the ATTO site, aged mineral dust and sea salts (37<span class='thinspace'></span>%-70<span class='thinspace'></span>%) as well as SOA and ammonium sulfate (28<span class='thinspace'></span>%-58<span class='thinspace'></span>%) were abundant. PBAs were observed abundantly in the PM<span class='inline-formula'>₂₋₄</span> fraction (46<span class='thinspace'></span>%), and EC and fly ash particles were absent in all size fractions. The analysis of a bulk PM<span class='inline-formula'>_0.25−0.5</span> aerosol sample from the ATTO site using Raman microspectrometry and attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) showed that ammonium sulfate, organics, and minerals are the major chemical species, which is consistent with the ED-EPMA results. In the submicron aerosols collected in Manaus, either SOA and ammonium sulfate (17<span class='thinspace'></span>%-80<span class='thinspace'></span>%) or EC particles (6<span class='thinspace'></span>%-78<span class='thinspace'></span>%) were dominant depending on the samples. In contrast, aged mineral dust, reacted sea salt, PBA, SOA, ammonium sulfate, and EC particles comprised most of the supermicron aerosols collected in Manaus. The SOA, ammonium sulfate, and PBAs were mostly of a biogenic origin from the rainforest, whereas the EC and HM-containing particles were of an anthropogenic origin. Based on the different contents of SOA, ammonium sulfate, and EC particles among the samples collected in Manaus, a considerable influence of the rainforest over the city was observed. Aged mineral dust and reacted sea-salt particles, including mineral dust mixed with sea salts probably during long-range transatlantic transport, were abundant in the supermicron fractions at both sites. Among the aged mineral dust and reacted sea-salt particles, sulfate-containing ones outnumbered those containing nitrates and sulfate<span class='thinspace'></span><span class='inline-formula'>+</span><span class='thinspace'></span>nitrate in the ATTO samples. In contrast, particles containing sulfate<span class='thinspace'></span><span class='inline-formula'>+</span><span class='thinspace'></span>nitrate were comparable in number to particles containing sulfate only in the Manaus samples, indicating

Is Lymphedema Cure a Clinical Reality?

Chen Wei F.,Ku Ying C.,Yamamoto Takumi,Pandey Sonia K. 대한성형외과학회 2023 Archives of Plastic Surgery Vol.50 No.6

Three-dimensional Computational Modeling and Simulation of Intergranular Corrosion Propagation of Stainless Steel

( T. Igarashi ),( A. Komatsu ),( T. Motooka ),( F. Ueno ),( M. Yamamoto ) 한국부식방식학회 2021 Corrosion Science and Technology Vol.20 No.3

In oxidizing nitric acid solutions, stainless steel undergoes intergranular corrosion accompanied by grain dropping and changes in the corrosion rate. For the safe operation of reprocessing plants, this mechanism should be understood. In this study, we constructed a three-dimensional computational model using a cellular automata method to simulate the intergranular corrosion propagation of stainless steel. The computational model was constructed of three types of cells: grain (bulk), grain boundary (GB), and solution cells. Model simulations verified the relationship between surface roughness during corrosion and dispersion of the dissolution rate of the GB. The relationship was investigated by simulation applying a constant dissolution rate and a distributed dissolution rate of the GB cells. The distribution of the dissolution rate of the GB cells was derived from the intergranular corrosion depth obtained by corrosion tests. The constant dissolution rate of the GB was derived from the average dissolution rate. Surface roughness calculated by the distributed dissolution rates of the GBs of the model was greater than the constant dissolution rates of the GBs. The cross-sectional images obtained were comparable to the corrosion test results. These results indicate that the surface roughness during corrosion is associated with the distribution of the corrosion rate.

EFFECT OF ENVIRONMENTAL TEMPERATURES ON HEAT PRODUCTION IN DAIRY HEIFERS DIFFERING IN FEED INTAKE LEVEL

Purwanto, B.P.,Nakamasu, F.,Yamamoto, Sadaki Asian Australasian Association of Animal Productio 1993 Animal Bioscience Vol.6 No.2

A study using dairy heifers was conducted to determine the effect of environmental temperature on heat production differing in feed intake level. The design consisted of three levels of feed intake (low, medium and high) and two environmental chamber temperature (15 and $30^{\circ}C$) with four replications in each treatment. Rectal temperature (RT), respiration rate (RR), heart rate (HR) and heat production (HP) were then measured. At the both environmental temperature, RT, RR and HR increased with the increase in feed intake level. The RT and RR also increased with the elevation of environmental temperature. The HP of $30^{\circ}C$ was significantly higher (4.8-8.9%) than $15^{\circ}C$. The estimated metabolizable energy requirement for maintenance (MEm) was higher (p<0.05) at $30^{\circ}C$ ($554.7kJ/kg^{0.75}$ d) than $15^{\circ}C$ (464.9 kJ/kgd). It was suggested that the decreasing in productive efficiency under hot environmental conditions partly associated with the increase in HP, which associated with the change in heat loss mechanism from sensible path to evaporative path.

Association of genetic variation in <i>FTO</i> with risk of obesity and type 2 diabetes with data from 96,551 East and South Asians

Li, H.,Kilpelä,inen, T. O.,Liu, C.,Zhu, J.,Liu, Y.,Hu, C.,Yang, Z.,Zhang, W.,Bao, W.,Cha, S.,Wu, Y.,Yang, T.,Sekine, A.,Choi, B. Y.,Yajnik, C. S.,Zhou, D.,Takeuchi, F.,Yamamoto, K.,Chan, J. C.,Man Springer-Verlag 2012 Diabetologia Vol.55 No.4

<P><B>Aims/hypothesis</B></P><P><I>FTO</I> harbours the strongest known obesity-susceptibility locus in Europeans. While there is growing evidence for a role for <I>FTO</I> in obesity risk in Asians, its association with type 2 diabetes, independently of BMI, remains inconsistent. To test whether there is an association of the <I>FTO</I> locus with obesity and type 2 diabetes, we conducted a meta-analysis of 32 populations including 96,551 East and South Asians.</P><P><B>Methods</B></P><P>All studies published on the association between <I>FTO</I>-rs9939609 (or proxy [<I>r</I><SUP>2</SUP> > 0.98]) and BMI, obesity or type 2 diabetes in East or South Asians were invited. Each study group analysed their data according to a standardised analysis plan. Association with type 2 diabetes was also adjusted for BMI. Random-effects meta-analyses were performed to pool all effect sizes.</P><P><B>Results</B></P><P>The <I>FTO</I>-rs9939609 minor allele increased risk of obesity by 1.25-fold/allele (<I>p</I> = 9.0 × 10<SUP>−19</SUP>), overweight by 1.13-fold/allele (<I>p</I> = 1.0 × 10<SUP>−11</SUP>) and type 2 diabetes by 1.15-fold/allele (<I>p</I> = 5.5 × 10<SUP>−8</SUP>). The association with type 2 diabetes was attenuated after adjustment for BMI (OR 1.10-fold/allele, <I>p</I> = 6.6 × 10<SUP>−5</SUP>). The <I>FTO</I>-rs9939609 minor allele increased BMI by 0.26 kg/m<SUP>2</SUP> per allele (<I>p</I> = 2.8 × 10<SUP>−17</SUP>), WHR by 0.003/allele (<I>p</I> = 1.2 × 10<SUP>−6</SUP>), and body fat percentage by 0.31%/allele (<I>p</I> = 0.0005). Associations were similar using dominant models. While the minor allele is less common in East Asians (12–20%) than South Asians (30–33%), the effect of <I>FTO</I> variation on obesity-related traits and type 2 diabetes was similar in the two populations.</P><P><B>Conclusions/interpretation</B></P><P><I>FTO</I> is associated with increased risk of obesity and type 2 diabetes, with effect sizes similar in East and South Asians and similar to those observed in Europeans. Furthermore, <I>FTO</I> is also associated with type 2 diabetes independently of BMI.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (doi:10.1007/s00125-011-2370-7) contains peer-reviewed but unedited supplementary material, which is available to authorised users.</P>

Progress in development of neutron energy spectrometer for deuterium plasma operation in KSTAR.

Tomita, H,Yamashita, F,Nakayama, Y,Morishima, K,Yamamoto, Y,Sakai, Y,Cheon, M S,Isobe, M,Ogawa, K,Hayashi, S,Kawarabayashi, J,Iguchi, T American Institute of Physics 2014 Review of scientific instruments Vol.85 No.11

<P>Two types of DD neutron energy spectrometer (NES) are under development for deuterium plasma operation in KSTAR to understand behavior of beam ions in the plasma. One is based on the state-of-the-art nuclear emulsion technique. The other is based on a coincidence detection of a recoiled proton and a scattered neutron caused by an elastic scattering of an incident DD neutron, which is called an associated particle coincidence counting-NES. The prototype NES systems were installed at J-port in KSTAR in 2012. During the 2012 and 2013 experimental campaigns, multiple shots-integrated neutron spectra were preliminarily obtained by the nuclear emulsion-based NES system.</P>

Current practices and recent advances in condition assessment of aged ships

Rizzo, C. M.,Paik, J. K.,Brennan, F.,Carlsen, C. A.,Daley, C.,Garbatov, Y.,Ivanov, L.,Simonsen, B. C.,Yamamoto, N.,Zhuang, H. Z. Taylor Francis 2007 SHIPS AND OFFSHORE STRUCTURES Vol.2 No.3

<P> Ship structures are likely to be subject to age-related deterioration such as corrosion wastage, cracking or mechanical damage. It has reportedly been recognised that such age-related deterioration is almost always involved in the catastrophic failures of ship structures including total losses. While such accidents typically cause concern to the public, maintenance and repair of aged structures is quite costly and complex. It is thus of great importance to develop advanced technologies allowing for proper management and control of such age-related deterioration. This paper summarises the report of the ISSC 2006 Committee V.6 presenting current practices, recent advances and future trends on condition assessment of aged ships. This includes assessment of the structural condition in view of the serviceability and safety, methods for repair, quantification of strength of deteriorated and repaired ships (as well as criteria for acceptable damage), with due account of the uncertainties involved. Consideration is also given to cost-benefit and risk-based decision procedures for remedial actions.</P>

EFFECT OF CHEWING TIME OF DIETS ON RUMEN FERMENTATION AND MILK PRODUCTION IN DAIRY COWS

Sakurai, K.,Fujishiro, S.,Shinjoh, K.,Honzawa, N.,Yamamoto, F.,Tomabechi, T.,Yoshida, M.,Takahashi, A.,Itabashi, H.,Abe, A. Asian Australasian Association of Animal Productio 1989 Animal Bioscience Vol.2 No.3

EFFECT OF STANDING AND LYING BEHAVIORS ON HEAT PRODUCTION OF DAIRY HEIFERS DIFFERING IN FEED INTAKE LEVELS

Purwanto, B.P.,Matsumoto, T.,Nakamasu, F.,Ito, T.,Yamamoto, Sadaki Asian Australasian Association of Animal Productio 1993 Animal Bioscience Vol.6 No.2

Four Holstein heifers were used in the present study to investigate the effect of standing and lying behaviors on heat production and physiological responses under low (L), medium (M) and high (H) levels of TDN intake. Rectal temperature (RT), respiration rate (RR), heart rate (HR), heat production (HP) and animals behavior (standing time, ST) were measured continuously for 5h (11:00-16:00) periods. There was a tendency for increased RT with TDN intake, and no difference in RT was observed between standing and lying. The RR, HR and HP during standing were significantly higher (p<0.05) than during lying. The difference between standing and lying HP were 4.41, 4.68 and $5.37kJ/kg^{0.75}$ h for L, M and H of TDN intake, respectively. These values showed that standing HP was 18.6-20.9% higher than lying HP. A multiple regression analysis of HP ($kJ/kg^{0.75}$ h) on TDN intake ($g/kg^{0.75}$ d) and ST (min/h) was HP = 7.75 + 0.28 TDN intake + 0.12 ST (R = 0.84). This analysis showed that the total HP not only depend on feed intake levels, but also depends on animal behavior. It was suggested that the change in HP due to the change in feed intake and animal behavior would influence the level of heat loss which was indicated by the changes in the RR and HR.