521 results on '"Tatsuya, Sato"'
Search Results
502. Passive Thermal Control of Pressurized Modules of JEM
- Author
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Tatsuya Sato, Fumiya Tsutsui, Kentaro Shoji, Hiroyoshi Ono, and Toshiyuki Shishido
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Materials science ,business.industry ,Thermal control system ,Aerospace engineering ,business - Published
- 2000
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503. Capillary Electrophoresis System using Biological Reaction of Single Cell as a Sensor Probe
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Tsutomu Araki, Takeshi Yasui, Mamoru Hashimoto, and Tatsuya Sato
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Chromatography ,medicine.anatomical_structure ,Capillary electrophoresis ,Biological reaction ,Chemistry ,Cell ,Analytical chemistry ,medicine - Published
- 2000
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504. Effect of Calcination Conditions on Porous Reduced Titanium Oxides and Oxynitrides via a Preceramic Polymer Route.
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George Hasegawa, Tatsuya Sato, Kazuyoshi Kanamori, Cheng-Jun Sun, Yang Ren, Yoji Kobayashi, Hiroshi Kageyama, Takeshi Abe, and Kazuki Nakanishi
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CALCINATION (Heat treatment) , *TITANIUM oxides , *PRECERAMICS , *PHASE transitions , *NITRIDATION - Abstract
A preceramic polymer route from Ti-based inorganic-organic hybrid networks provides electroconductive N-doped reduced titanium oxides (TinO2n-1) and titanium oxynitrides (TiOxNy) with a monolithic shape as well as well-defined porous structures. This methodology demonstrates an advantageously lower temperature of the crystal phase transition compared to the reduction of TiO2 by carbon or hydrogen. In this study, the effect of calcination conditions on various features of the products has been explored by adopting three different atmospheric conditions and varying the calcination temperature. The detailed crystallographic and elemental analyses disclose the distinguished difference in the phase transition behavior with respect to the calcination atmosphere. The correlation between the crystallization and nitridation behaviors, porous properties, and electric conductivities in the final products is discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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505. Does glycemic control reverse dispersion of ventricular repolarization in type 2 diabetes?
- Author
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Takayuki Miki, Toshiyuki Tobisawa, Tatsuya Sato, Masaya Tanno, Toshiyuki Yano, Hiroshi Akasaka, Atsushi Kuno, Makoto Ogasawara, Hiromichi Murase, Shigeyuki Saitoh, and Tetsuji Miura
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GLYCEMIC index ,PEOPLE with diabetes ,CARDIOVASCULAR diseases ,ELECTROCARDIOGRAPHY ,CHOLESTEROL - Abstract
Background Abnormal ventricular repolarization is a predictor of cardiovascular mortality. In this study, we tested the hypothesis that glycemic control reverses abnormal ventricular repolarization in patients with type 2 diabetes. Methods We analyzed longitudinal changes in repolarization indices of electrocardiograms in retrospectively enrolled 44 patients with type 2 diabetes and 44 age-matched healthy subjects. Results In the diabetic group, BMI was greater, levels of HbA1c (10.0 ± 1.6 vs. 5.6 ± 0.3%) and triglyceride were higher and level of HDL cholesterol was lower than those in the control group. Although mean QTc intervals were similar (413.6 ± 18.5 vs. 408.3 ± 22.7 ms), QT dispersion (41.8 ± 15.4 vs. 28.7 ± 7.7 ms) and Tpeak-Tend in lead V5 (83.6 ± 13.6 vs. 71.3 ± 10.3 ms) were significantly longer in the diabetic group than in the control group, indicating increased heterogeneity of ventricular repolarization in type 2 diabetes. During follow-up of 36 patients in the diabetic group for 787 ± 301 days, HbA1c level decreased to 7.3 ± 1.6%, while BMI did not significantly change. In contrast to HbA1c, QT dispersion (45.8 ± 15.0 ms) and Tpeak-Tend in lead V5 (83.6 ± 10.6 ms) were not significantly reduced during the follow-up period. There was no correlation between the change in HbA1c and the change in QT dispersion or Tpeak-Tend. Conclusions Increased heterogeneity of ventricular repolarization in type 2 diabetic patients was not reduced during the relatively short follow-up period despite significantly improved glycemic control. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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506. Early weight-bearing after periacetabular osteotomy leads to a high incidence of postoperative pelvic fractures.
- Author
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Hiroshi Ito, Hiromasa Tanino, Tatsuya Sato, Yasuhiro Nishida, and Takeo Matsuno
- Abstract
Background: It has not been shown whether accelerated rehabilitation following periacetabular osteotomy (PAO) is effective for early recovery. The purpose of this retrospective study was to compare complication rates in patients with standard and accelerated rehabilitation protocols who underwent PAO. Methods: Between January 2002 and August 2011, patients with a lateral center-edge (CE) angle of < 20°, showing good joint congruency with the hip in abduction, pre- or early stage of osteoarthritis, and age younger than 60 years were included in this study. We evaluated 156 hips in 138 patients, with a mean age at the time of surgery of 30 years. Full weight-bearing with two crutches started 2 months postoperatively in 73 patients (80 hips) with the standard rehabilitation protocol. In 65 patients (76 hips) with the accelerated rehabilitation protocol, postoperative strengthening of the hip, thigh and core musculature was begun on the day of surgery as tolerated. The exercise program included active hip range of motion, and gentle isometric hamstring and quadriceps muscle sets; these exercises were performed for 30 minutes in the morning and 30 minutes in the afternoon with a physical therapist every weekday for 6 weeks. Full weight-bearing with two axillary crutches started on the day of surgery as tolerated. Complications were evaluated for 2 years. Results: The clinical results at the time of follow-up were similar in the two groups. The average periods between the osteotomy and full-weight-bearing walking without support were 4.2 months and 6.9 months in patients with the accelerated and standard rehabilitation protocols (P < 0.001), indicating that the accelerated rehabilitation protocol could achieve earlier recovery of patients. However, postoperative fractures of the ischial ramus and posterior column of the pelvis were more frequently found in patients with the accelerated rehabilitation protocol (8/76) than in those with the standard rehabilitation protocol (1/80) (P = 0.013). Conclusion: The accelerated rehabilitation protocol seems to have advantages for early muscle recovery in patients undergoing PAO; however, postoperative pelvic fracture rates were unacceptably high in patients with this protocol. [ABSTRACT FROM AUTHOR]
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- 2014
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507. The Effect of Cognitions of Parental Expectations on University Students' Personality of Self-inhibition and Life Satisfaction: Focusing on Styles of Reaction to Expectations.
- Author
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Hideaki Kasuga, Hiroshi Utsunomiya, and Tatsuya Sato
- Abstract
This study investigated how parental expectations for their college-age children were related to their children's reaction styles, self-inhibition, and life satisfaction. Undergraduate students (N=367) completed a questionnaire that assessed parental expectations, their feelings about and reactions to these expectations, and students' self-inhibition and life satisfaction. The results indicated that students' reaction styles and life satisfaction differed according to their feelings of parental expectations. Students who thought about parental expectations only in terms of their careers and with regard to being a good child felt more of a burden, whereas students who thought about their parents' high expectations regarding personality, career, and being a good child reacted more positively to the parental expectations. In addition, the personality characteristic of self-inhibition in the latter group appeared to enhance their life satisfaction. These results suggest that not only parental expectations for children's careers, but also children's ways of thinking about their parents' expectations are important for a fuller understanding of the impact of parental expectations. [ABSTRACT FROM AUTHOR]
- Published
- 2014
508. Type 2 diabetes induces subendocardium-predominant reduction in transient outward K+ current with downregulation of Kv4.2 and KChIP2.
- Author
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Tatsuya Sato, Takeshi Kobayashi, Atsushi Kuno, Takayuki Miki, Masaya Tanno, Hidemichi Kouzu, Takahito Itoh, Satoko Ishikawa, Takashi Kojima, Tetsuji Miura, and Noritsugu Tohse
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TYPE 2 diabetes , *LABORATORY rats , *PROTEIN-protein interactions , *MESSENGER RNA , *HOMEOBOX proteins - Abstract
In the present study, we examined if and how cardiac ion channels are modified by type 2 diabetes mellitus (T2DM). Subendocardial (Endo) myocytes and subepicardial (Epi) myocytes were isolated from left ventricles of Otsuka-Long-Evans-Tokushima Fatty rats (OLETF) rats, a rat model of T2DM, and Otsuka-Long-Evans-Tokushima (LETO) rats (nondiabetic control rats). Endo and Epi myocytes were used for whole cell patch-clamp recordings and for protein and mRNA analyses. Action potential durations in Endo and Epi myocytes were longer in OLETF rats than in LETO rats, and the difference was larger in Endo myocytes. Steady-state transient outward K+ current (Ito) density was reduced in Endo but not Epi myocytes of OLETF rats compared with LETO rats, although the contribution of the fast component of Ito recovery from inactivation was smaller in both Endo and Epi myocytes of OLETF rats than in LETO rats. Kv4.2 protein was reduced only in Endo myocytes in OLETF rats, although voltage-gated K+ channel-interacting protein 2 (KChIP2) protein levels in both Endo and Epi myocytes were lower in OLETF rats than in LETO rats. Corresponding regional differences in mRNA levels of KChIP2 and Kv4.2 were observed between OLETF and LETO rats. mRNA levels of Iroquois homeobox 5 in Endo myocytes were 53% higher in OLETF rats than in LETO rats. Densities of inward rectifier K+ current and L-type Ca2+ current and mRNA levels of Kv4.3 and Kv1.4 were similar in OLETF and LETO rats. In conclusion, T2DM induces Endo-predominant prolongation of the action potential duration via a reduction of the fast component of Ito recovery from inactivation and reduced steady-state Ito, in which downregulation of Kv4.2 and KChIP2 may be involved. Increased Iroquois homeobox 5 expression may underlie Kv4.2 downregulation in T2DM. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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509. Analogues of Depression: From the Perspective of the Continuity of Depression.
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Shizuka KAWAMOTO, Takuya WATANABE, Koji KOSUGI, Koji MATSUO, Yoshifumi WATANABE, and Tatsuya SATO
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CLUSTER analysis (Statistics) ,COLLEGE students' psychology research ,AFFECTIVE disorders ,NEUROSES - Abstract
This study investigated aspects of analogues of depression. Cluster analysis and a symptoms approach were used to identify characteristics of analogues of depression. Patients with major depressive disorder provided the seed points for the depressed cluster, and non-distressed university students provided the seed points for the non-depressed cluster. The results showed that the non-depressed cluster included all the mild-depression subjects and part of the moderate-depression subjects of the distressed university students. On the other hand, the depressed cluster included other moderate-depression subjects and all the severe-depression subjects. These results indicate that the symptoms of mild depression among distressed university students have little in common with severe clinical depression. However there was a sequence of continuity between the symptoms of severe-depression subjects of the distressed university students and patients with severe clinical depression. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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510. Monitor of water pollution by the movement and fluorescence of Paramecium caudatum
- Author
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Tsutomu Araki, Shigeru Gotoh, Kensuke Chikamori, and Tatsuya Sato
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Botany ,Paramecium caudatum ,Biology ,Water pollution ,biology.organism_classification - Published
- 2002
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511. Pocket Money and Children's Sense about Money Matters in Japan, Korea, China, and Vietnam: Children's Affluence and Structure of Human Relations.
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Seon Ah, Oh, Kazuko, Takeo, Chengnan, Pian, Noboru, Takahashi, Toshiya, Yamamoto, and Tatsuya, Sato
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CHILDREN'S rights ,INTERPERSONAL relations ,PARENT-child relationships ,SOCIAL control ,SOCIAL norms - Abstract
In this study, children in four nations were compared concerning the thinking and activities of children with regard to money. A questionnaire survey was conducted on students in the 5th grade of elementary schools, 2nd grade of junior high schools, and 2nd grade of high schools in Japan, Korea, China, and Vietnam. The questions focused on the following points: how children get money, children's actual behavior and awareness of social norms (judgments of right and wrong), peer relationships, and parent-child relationships, in relation to children's use of money. The results were as follows. Children's experience using money was more profound and their attitudes about using money were more positive in this order: Japan, South Korea, China, and Vietnam. Japanese children were most aware and Vietnamese children least aware that pocket money was their own money. Japanese children, compared to Korean children, had more negative attitudes toward treating friends to foods and lending money within friends. Based on these results, a discussion followed concerning with affluence and poverty. [ABSTRACT FROM AUTHOR]
- Published
- 2012
512. The Person-situation Debate and the Assessment of Situations.
- Author
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FUNDER, David C., GUILLAUME, Esther, Sakiko KUMAGAI, Shizuka KAWAMOTO, and Tatsuya SATO
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PERSONALITY & situation ,DEBATE ,HUMAN behavior ,CROSS-cultural differences ,GENDER - Abstract
While the person-situation debate was largely based on a misunderstanding of the magnitude of the correlations that characterize relations between personality traits and behavior, it drew much-needed attention to the importance of situations. However, few attempts have been made to understand the important elements of situations in relation to behavior. Current work developing the Riverside Situational Q-sort (RSQ) aims to provide a useful way to conceptualize and measure the behaviorally important attributes of situations. A current project is applying this method cross-culturally. New data from the US and Japan show that behavioral correlates of two elements of the situation--the presence of a member of the opposite sex and the experience of being criticized by others--have largely similar behavioral correlates between genders and across cultures. These analyses illustrate how the RSQ illuminates the connections between situations and behavior. Future research will extend such analyses to more situational attributes and other cultures around the world. [ABSTRACT FROM AUTHOR]
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- 2012
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513. Role of connexin-43 in protective PI3K-Akt-GSK-3β signaling in cardiomyocytes.
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Satoko Ishikawa, Atsushi Kuno, Masaya Tanno, Takayuki Miki, Hidemichi Kouzu, Takahito Itoh, Tatsuya Sato, Daisuke Sunaga, Hiromichi Murase, and Tetsuji Miura
- Abstract
Sarcolemmal connexin-43 (Cx43) and mitochondrial Cx43 play distinct roles: formation of gap junctions and production of reactive oxygen species (ROS) for redox signaling. In this study, we examined the hypothesis that Cx43 contributes to activation of a major cytoprotective signal pathway, phosphoinositide 3-kinase (PI3K)-Akt-glycogen synthase kinase-3β (GSK-3β) signaling, in cardiomyocytes. A δ-opioid receptor agonist {[D-Ala
2 ,DLeu5 ] enkephalin acetate (DADLE)}, endothelin-1 (ET-1), and insulin- like growth factor-1 (IGF-1) induced phosphorylation of Akt and GSK-3β in H9c2 cardiomyocytes. Reduction of Cx43 protein to 20% of the normal level by Cx43 small interfering RNA abolished phosphorylation of Akt and GSK-3β induced by DADLE or ET-1 but not that induced by IGF-1. DADLE and IGF-1 protected H9c2 cells from necrosis after treatment with H2 O2 or antimycin A. The protection by DADLE or ET-1, but not that by IGF-1, was lost by reduction of Cx43 protein expression. In contrast to Akt and GSK-3β, PKC-å, ERK and p38 mitogen-activated protein kinase were phosphorylated by ET-1 in Cx43-knocked-down cells. Like diazoxide, an activator of the mitochondrial ATP-sensitive K+ channel, DADLE and ET-1 induced significant ROS production in mitochondria, although such an effect was not observed for IGF-1. Cx43 knockdown did not attenuate the mitochondrial ROS production by DADLE or ET-1. Cx43 was coimmunoprecipitated with the β-subunit of G protein (Gβ), and knockdown of Gβ mimicked the effect of Cx43 knockdown on ET-1- induced phosphorylation of Akt and GSK-3β. These results suggest that Cx43 contributes to activation of class IB PI3K in PI3K-Akt- GSK-3β signaling possibly as a cofactor of Gβ in cardiomyocytes. [ABSTRACT FROM AUTHOR]- Published
- 2012
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514. Successful Endosonography-Guided Drainage of an Intra-Abdominal Abscess in a 1-Year-Old Infant.
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Yukiko Ito, Hiroyuki Isayama, Yousuke Nakai, Gyoutane Umefune, Tatsuya Sato, Saori Nakahara, Junko Suwa, Keiichi Kato, and Ryo Nakata
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ENDOSCOPIC ultrasonography ,ULCERS ,ABDOMINAL abscess ,DIAGNOSTIC ultrasonic imaging ,ENDOSCOPY - Abstract
Endoscopic ultrasound (EUS)-guided intervention has been established as a safe, effective and minimally invasive procedure for various diseases in adults, but there have been limited reports in pediatric patients. Herein, we report our experience with successful EUS-guided drainage of an intra-abdominal abscess in a 1-year-old infant concomitant with disseminated intravascular coagulation. The abscess was punctured via the stomach using a standard, convex-type echoendoscope, and the patient's condition improved after naso-cystic catheter placement. Although the clinical course was complicated by delayed hemorrhage from the puncture site, the bleeding was successfully managed by endoscopic hemostasis using a standard forward-viewing endoscope. [ABSTRACT FROM AUTHOR]
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- 2016
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515. Synthesis and Some Physical Properties of a New Series of Layered Selenides (LnO)CuSe (Ln=Lanthanides)
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Tsukio Ohtani, Kazuhiro Nagaoka, Makoto Iwabe, Masatomo Hirose, and Tatsuya Sato
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Lanthanide ,business.industry ,Chemistry ,Inorganic chemistry ,General Engineering ,General Physics and Astronomy ,Magnetic susceptibility ,Ion ,Degenerate semiconductor ,Crystallography ,Paramagnetism ,Semiconductor ,Electrical resistivity and conductivity ,business ,Solid solution - Abstract
A new series of layered selenides (LnO)CuSe (Ln=La, Ce, Nd, Sm, Gd, Tb, Dy, Ho, Y) with (LaO)AgS-type structure was prepared. All the compounds were semiconductors. Magnetic susceptibility measurements revealed that the lanthanide ions are in the trivalent state and the values of Weiss temperature θ lie within ±15 K for all the compounds. The preparation and the electrical resistivity of (LaO)Cu(S1-x Se x ) (0≤x≤1) and (La1-x Sr x )OCuSe (0≤x≤0.2) systems are also reported.
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- 1993
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516. n,.pi.* State of jet-cooled benzophenone as studied by sensitized phosphorescence excitation spectroscopy
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Mitsuo Ito, Shinichi Kamei, Naohiko Mikami, and Tatsuya Sato
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Chemistry ,General Engineering ,Analytical chemistry ,Dihedral angle ,Bond length ,chemistry.chemical_compound ,Crystallography ,Excited state ,Benzophenone ,Vibronic spectroscopy ,Emission spectrum ,Physical and Theoretical Chemistry ,Phosphorescence ,Excitation - Abstract
The sensitized phosphorescence excitation spectrum of jet-cooled benzophenone due to the S/sub 1/(n,..pi../sup */) produced from S/sub 0/ transition has been measured. It was found that the spectrum consists exclusively of several long progressions of 60 cm/sup -1/ which is the in-phase torsional mode of the phenyl rings. The vibrational analysis and the potential calculation shows that the in the S/sub 1/(n,..pi../sup */) state great geometry changes occur in the dihedral angle between the phenyl rings, the C=O bond distance, and the C-C bonds adjacent to the C=O bond.
- Published
- 1986
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517. On the Innervation of the Testicle and Epididymis of 7-8 Month Human Fetus
- Author
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Tatsuya Sato
- Subjects
endocrine system ,Plexus ,Histology ,Connective tissue ,Anatomy ,Testicle ,Biology ,Epididymis ,Tunica albuginea (ovaries) ,medicine.anatomical_structure ,Mediastinum testis ,Rete testis ,medicine ,Tunica - Abstract
The innervation of the testicle and the caput epididymidis originate in the plexus spermaticus and that of the corpus and the cauda epididymidis in the plexus deferentialis. Between the two kinds of plexus only slight anastomosis is to be observed.The plexus deferentialis is formed in the vasa deferentialis, spreads to the cauda epididymidis and thence into the corpus epididymidis and turns into the plexus ductus epididymidis. The plexus spermaticus runs through the plexus pampiniformis and thence spreads into the caput epididymis and the testicle. In the former part it forms the plexus ductuli efferentis, but in the latter, it passes first over into the plexus mediastinalis testis and the largest part of its nerve elements runs thence into the tunica vasculosa and finally spread out into the interstitial connective tissue through the septula testis. A small part of the nerve fibres of the plexus mediastinalis testis, however, run through the rete testis into the parenchyma testis.The plexus ductus epididymidis is very well developed already in the later fetal stage and comes into frequent anastomosis with the perivascular plexus running along the blood vessels. The vegetative fibres always develop into preterminal fibres and thence into STOHR's terminal reticula, which come into control by contact over the smooth muscle cells. The development of the vegetative fibres is particularly powerful in the cauda epididymidis where the muscle layer of the ductus is well developed.The plexus ductuli efferentis is far poorer in development than the plexus ductus epididymidis, due to the poor development of the muscle fibres in this part. The vegetative fibres here too end in STOHR's terminal reticula, which run as far as into the membrana propria but not further in the epithelial cells of the ductuli. STOHR's terminal reticula are formed in the interstitial connective tissue of the testicle too, but in the fetal stage, they are far poorer in development than in human adults. The terminal reticula here stand in control by contact over the LEYDIG's cells.A small number of sensory fibres are found in the plexus spermaticus. These probably originate in the branches of the nn. sacrales running into the plexus hypogastricus.The sensory terminations found in the testicle and the epididymis, being originated in the sensory fibres running in the plexus spermaticus, are present in the testicle and the caput epididymidis, but scarcely in the corpus and the cauda epididymidis.The sensory fibres running toward the mediastinum testis seem to be somewhat more numerous than those directed toward the caput epididymidis. The former part from the vegetative fibres upon reaching the rete testis, run through the connective tissue lining the rete or between its ducts and end in unbranched and simple branched terminations. Their terminal fibres show frequent change in size and usually end in sharp points. Often they penetrate into the one-rowed epithelium of the rete and end as intraepithelial fibres.The above findings are not much different from those obtained in adult human specimens by YAMASHITA. Thus, the sensory terminations in these parts seem to reach nearly complete formation in the fetal stage. Not rarely are found sensory fibres running further beyond the rete testis into the tunica albuginea and forming their terminations there. In the parenchyma testis, however, no sensory termination has been found.In the corpus and the cauda epididymidis no sensory termination has been adequately ascertained, but in the caput epididymidis may be seen some unbranched and simple branched terminations similar to those found in the rete located in the interstitial connective tissue of the ductuli efferentes. But here no intraepithelial fibres as found in the rete testis are observed.
- Published
- 1957
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518. Does glycemic control reverse dispersion of ventricular repolarization in type 2 diabetes?
- Author
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Shigeyuki Saitoh, Toshiyuki Yano, Tatsuya Sato, Atsushi Kuno, Hiroshi Akasaka, Hiromichi Murase, Takayuki Miki, Masaya Tanno, Toshiyuki Tobisawa, Makoto Ogasawara, and Tetsuji Miura
- Subjects
Blood Glucose ,Male ,medicine.medical_specialty ,Ventricular Repolarization ,Endocrinology, Diabetes and Metabolism ,Type 2 diabetes ,Electrocardiography ,Glycemic control ,Internal medicine ,Diabetes mellitus ,medicine ,Ventricular Dysfunction ,Humans ,cardiovascular diseases ,Longitudinal Studies ,Cardiovascular mortality ,Glycemic ,Angiology ,Original Investigation ,Aged ,Retrospective Studies ,medicine.diagnostic_test ,business.industry ,Middle Aged ,medicine.disease ,Ventricular repolarization ,Glycemic index ,Diabetes Mellitus, Type 2 ,QT dispersion ,Glycemic Index ,cardiovascular system ,Cardiology ,Female ,business ,Cardiology and Cardiovascular Medicine ,Follow-Up Studies - Abstract
Background Abnormal ventricular repolarization is a predictor of cardiovascular mortality. In this study, we tested the hypothesis that glycemic control reverses abnormal ventricular repolarization in patients with type 2 diabetes. Methods We analyzed longitudinal changes in repolarization indices of electrocardiograms in retrospectively enrolled 44 patients with type 2 diabetes and 44 age-matched healthy subjects. Results In the diabetic group, BMI was greater, levels of HbA1c (10.0 ± 1.6 vs. 5.6 ± 0.3%) and triglyceride were higher and level of HDL cholesterol was lower than those in the control group. Although mean QTc intervals were similar (413.6 ± 18.5 vs. 408.3 ± 22.7 ms), QT dispersion (41.8 ± 15.4 vs. 28.7 ± 7.7 ms) and Tpeak-Tend in lead V5 (83.6 ± 13.6 vs. 71.3 ± 10.3 ms) were significantly longer in the diabetic group than in the control group, indicating increased heterogeneity of ventricular repolarization in type 2 diabetes. During follow-up of 36 patients in the diabetic group for 787 ± 301 days, HbA1c level decreased to 7.3 ± 1.6%, while BMI did not significantly change. In contrast to HbA1c, QT dispersion (45.8 ± 15.0 ms) and Tpeak-Tend in lead V5 (83.6 ± 10.6 ms) were not significantly reduced during the follow-up period. There was no correlation between the change in HbA1c and the change in QT dispersion or Tpeak-Tend. Conclusions Increased heterogeneity of ventricular repolarization in type 2 diabetic patients was not reduced during the relatively short follow-up period despite significantly improved glycemic control.
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519. Regulatory role of AMP-activated protein kinase in corticotropin releasing hormone secreting neurons in the paraventricular hypothalamus in social stress-induced alteration of food selection behavior
- Author
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Tatsuya, SATO
520. Transient Outward K+ Current (ITo) is Reduced Especially in the Subendocardium via Downregulation of Kv4.2 and KChIP2 Gene Expression in Obese Type2 Diabetic Rat Hearts
- Author
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Atsushi Kuno, Takayuki Miki, Tetsuji Miura, Masaya Tanno, Takeshi Kobayashi, Noritsugu Tohse, and Tatsuya Sato
- Subjects
Membrane potential ,medicine.medical_specialty ,endocrine system ,endocrine system diseases ,Inward-rectifier potassium ion channel ,Chemistry ,Biophysics ,macromolecular substances ,Endocrinology ,Downregulation and upregulation ,Internal medicine ,Gene expression ,medicine ,Repolarization ,Patch clamp ,Endocardium ,Ion channel - Abstract
Background: Cardiacion channel remodeling in type 2 diabetes mellitus (T2DM) remains far less understood than in type 1 DM (T1DM). Here, we examined if and how cardiac ion channels were modified by T2DM using OLETF, a rat model of obese T2DM.Methods and Results: We isolated left ventricular (LV) cardiomyocytes from epicardial (EPI) and endocardial (END) regions for whole-cell patch clamp. Action potential duration at 50% repolarization (APD50) at 1 Hz was significantly longer in OLETF than in non-diabetic control (LETO) (EPI; 8.89±1.04 vs. 5.20±0.75 ms, END; 22.01±3.64 vs. 9.89±1.74 ms). Resting membrane potential and membrane capacitances were similar among all groups. L-type Ca2+ current (ICa,L), inward rectifier K+ current (IK1) were comparable between OLETF and LETO. On the other hand, in the END but not the EPI cardiomyocytes, transient outward K+ current (Ito) density at 0.1Hz was significantly decreased in OLETF compared to LETO (END; 8.77±0.79 vs. 14.50±1.31, pA/pF at +60mV). In both END and EPI cardiomyocytes, the fast recovering component from inactivation of Ito was significantly decreased in OLETF compared to LETO. Quantitative RT-PCR analysis of genes encoding Ito subunits showed that the mRNA levels of Kv4.2 and KChIP2 were significantly reduced by 71% and 34%, respectively, in the END but not the EPI tissue in OLETF compared to those in LETO. The mRNA levels of the other Ito subunits were comparable in OLETF and LETO.Conclusions: The Ito current was reduced predominantly in the endocardium in T2DM, presumably by downregulation of Kv4.2 and KChIP2. This regional difference in Ito has not been reported for T1DM and may be characteristic to T2DM.
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521. SIRT2 inhibition protects against cardiac hypertrophy and ischemic injury.
- Author
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Xiaoyan Yang, Hsiang-Chun Chang, Yuki Tatekoshi, Mahmoodzadeh, Amir, Balibegloo, Maryam, Najafi, Zeinab, Rongxue Wu, Chunlei Chen, Tatsuya Sato, Shapiro, Jason, and Ardehali, Hossein
- Subjects
- *
CARDIAC hypertrophy , *SIRTUINS , *HEART size , *HEART injuries , *REPERFUSION , *WOUNDS & injuries , *CYTOPLASM - Abstract
Sirtuins (SIRT) exhibit deacetylation or ADP-ribosyltransferase activity and regulate a wide range of cellular processes in the nucleus, mitochondria, and cytoplasm. The role of the only sirtuin that resides in the cytoplasm, SIRT2, in the development of ischemic injury and cardiac hypertrophy is not known. In this paper, we show that the hearts of mice with deletion of Sirt2 (Sirt2-/-) display improved cardiac function after ischemia-reperfusion (I/R) and pressure overload (PO), suggesting that SIRT2 exerts maladaptive effects in the heart in response to stress. Similar results were obtained in mice with cardiomyocyte-specific Sirt2 deletion. Mechanistic studies suggest that SIRT2 modulates cellular levels and activity of nuclear factor (erythroid-derived 2)-like 2 (NRF2), which results in reduced expression of antioxidant proteins. Deletion of Nrf2 in the hearts of Sirt2-/- mice reversed protection after PO. Finally, treatment of mouse hearts with a specific SIRT2 inhibitor reduced cardiac size and attenuates cardiac hypertrophy in response to PO. These data indicate that SIRT2 has detrimental effects in the heart and plays a role in cardiac response to injury and the progression of cardiac hypertrophy, which makes this protein a unique member of the SIRT family. Additionally, our studies provide a novel approach for treatment of cardiac hypertrophy and injury by targeting SIRT2 pharmacologically, providing a novel avenue for the treatment of these disorders. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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