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Ishii K, Izaki T, Asahara R, Komine H. Carotid sinus baroafferent signals contribute to cerebral blood flow regulation during acute hypotension in young males: A randomized crossover study. Physiol Rep 2024; 12:e15937. [PMID: 38325901 PMCID: PMC10849886 DOI: 10.14814/phy2.15937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 01/10/2024] [Accepted: 01/21/2024] [Indexed: 02/09/2024] Open
Abstract
Cerebral autoregulation is an important factor in prevention of cerebral ischemic events. We tested a traditional but unproven hypothesis that carotid sinus baroafferent signals contribute to dynamic cerebral autoregulation. Middle cerebral artery mean blood velocity (MCA Vmean ) responses to thigh-cuff deflation-induced acute hypotension were compared between conditions using neck suction soon after cuff deflation, without or with a cushion wrapped around the upper neck, in nine healthy males (aged 25 ± 5 years). Neck suction was applied close to the hypotension. The MCA Vmean response was expected to differ between conditions because the cushion was presumed to prevent the carotid sinus distension by neck suction. The cushion hindered bradycardia and depressor responses during sole neck suction. Thigh-cuff deflation decreased mean arterial blood pressure (MAP) and MCA Vmean (Ps < 0.05) with an almost unchanged respiratory rate under both conditions. However, in the neck suction + cushion condition, subsequent MCA Vmean restoration was faster and greater (Ps ≤ 0.0131), despite similar changes in MAP in both conditions. Thus, carotid sinus baroafferent signals would accelerate dynamic cerebral autoregulation during rapid hypotension in healthy young males. Elucidating the mechanism underlying cerebral neural autoregulation could provide a new target for preventing cerebral ischemic events.
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Affiliation(s)
- Kei Ishii
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Tsubasa Izaki
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and TechnologyTsukubaJapan
- School of Economics & ManagementKochi University of TechnologyKochiJapan
| | - Ryota Asahara
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Hidehiko Komine
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and TechnologyTsukubaJapan
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Ishii K, Machino T, Hatori Y, Gwak J, Izaki T, Komine H. Differential relationship between decreased muscle oxygenation and blood pressure recovery during supraventricular and ventricular tachycardia. Sci Rep 2023; 13:15886. [PMID: 37741868 PMCID: PMC10517960 DOI: 10.1038/s41598-023-42908-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 09/15/2023] [Indexed: 09/25/2023] Open
Abstract
Vasoconstriction during tachyarrhythmia contributes to maintenance of arterial pressure (AP) by decreasing peripheral blood flow. This cross-sectional observational study aimed to ascertain whether the relationship between peripheral blood flow and AP recovery occurs during both paroxysmal supraventricular (PSVT, n = 19) and ventricular tachycardias (VT, n = 17). Peripheral blood flow was evaluated using forearm tissue oxygen index (TOI), and mean AP (MAP) was measured using a catheter inserted in the brachial or femoral artery during an electrophysiological study. PSVT and VT rapidly decreased MAP with a comparable heart rate (P = 0.194). MAP recovered to the baseline level at 40 s from PSVT onset, but not VT. The forearm TOI decreased during both tachyarrhythmias (P ≤ 0.029). The TOI response was correlated with MAPrecovery (i.e., MAP recovery from the initial rapid decrease) at 20-60 s from PSVT onset (r = -- 0.652 to - 0.814, P ≤ 0.0298); however, this association was not observed during VT. These findings persisted even after excluding patients who had taken vasoactive drugs. Thus, restricting peripheral blood flow was associated with MAP recovery during PSVT, but not VT. This indicates that AP recovery depends on the type of tachyarrhythmia: different cardiac output and/or vasoconstriction ability during tachyarrhythmia.
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Affiliation(s)
- Kei Ishii
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan
| | - Takeshi Machino
- Department of Cardiology, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yasuhiro Hatori
- Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi, Japan
| | - Jongseong Gwak
- Department of Computer Science, Takushoku University, Hachioji, Tokyo, Japan
| | - Tsubasa Izaki
- School of Economics and Management, Kochi University of Technology, Kochi, Kochi, Japan
| | - Hidehiko Komine
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan.
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Arichi A, Yorimitu T, Omura N, Ito K, Komine H, Kudo Y, Shimizu Y, Kawamura T, Ohara M, Sasaki H, Honma S, Hasui M, Takemura Y, Teraoka K, Ishikawa T. P-205 Blastocyst derived from oocytes with smooth endoplasmic reticulum aggregates (SERa) has similar clinical and perinatal outcomes with those of oocytes without SER. Hum Reprod 2022. [DOI: 10.1093/humrep/deac107.198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Study question
This study was to investigate effect of SERa on the fertilization rate, embryonic development after ICSI, and clinical and perinatal outcomes after single blastocyst transfer.
Summary answer
SERa (+) derived embryo can be selected as embryos for transfer when no available SERa (-) derived embryos.
What is known already
Based on findings that the risk of congenital abnormalities in the newborn is higher in ovum with SERa in the cytoplasm, the Istanbul consensus workshop at the 2011 meeting of the ESHRE recommended against fertilizing ovum with SERa due to these risks. However, there have been several reports of healthy infants born from embryos derived from SERa, suggesting that, while more long-term follow-up is necessary, healthy births are possible from such embryos. In 2017, the 2011 recommendations were reviewed in the Alpha/ESHRE consensus (Vienna), which said the approach should be determined on a case-by-case basis.
Study design, size, duration
We retrospectively investigated 23,007 oocytes which was retrieved between January 2016 and March 2020. Of these, 1,038 oocytes (4.5%) with visible SERa comprised SERa (+), while 21,969 oocytes (95.5%) without SERa comprised SERa (-).
Participants/materials, setting, methods
SERa were observed under the microscopy after denudation. The rate of fertilization, good-quality day-3 embryos, good-quality day-5 blastocysts, and day-5, 6 or 7 blastocysts were evaluated for both groups. We also compared the rate of clinical pregnancy, live birth, miscarriage, and birth defects in single blastocyst transfer between SERa (+) derived 114 blastocysts and SERa (-) derived 6,290 blastocysts from January 2016 and December 2018.
Main results and the role of chance
The results are shown. 2PN fertilization rate outcomes after ICSI (SERa(-) eggs vs. SERa(+)eggs),81.4%(17,873/21,969) vs.79.4% (823/1,038),and good-quality day3 rate was 61.1%(10,927/17,873)vs.60.9% (501/823) which was not significantly different. Good-quality day5 blastocyst rate was 46.5% (7,876/16,955) vs. 39.8%(304/763), and day 5 blastocyst success rate was 60.8% (10,317/16,955) vs.54.3% (414/763), which were both significantly lower with SERa(+). (P < 0.001) The day 6 blastocyst success rate was 69.9% (11,849/16,955) vs. 65.5% (500/763) (P = 0.01), and the day 7 blastocyst success rate was 70.9% (12,024/16,955) vs. 67.5% (515/763) (P = 0.04), which were all significantly lower with SERa(+).The clinical pregnancy rate was 39.4% (2,481/6,290) vs. 35.1% (40/114), the live birth rate was 27.7% (1,745/6,290) vs. 26.3% (30/114), and the miscarriage rate was 27.5% (683/2,481) vs. 20.0% (8/40) and the congenital abnormality rate was 1.6% (29/1,757) vs. 0% (0/30) for SERa(-) embryos and SERa(+) embryos, respectively, which were not significantly different. Blastocyst derived from oocytes with SERa has similar clinical and perinatal outcomes with those of oocytes without SERa. Significant differences were examined using the chi-squared test, with p < 0.05, indicating a significant difference.
Limitations, reasons for caution
Embryos derived SERa (+) were transferred when the patient did not want any more oocytes retrievals, no embryos derived SERa (-) were available, and only if the couple desired embryo transfer after the problems associated with SERa (+) embryos were fully explained.
Wider implications of the findings
To the best of our knowledge, this study is the largest number of live births investigating the outcome of SERa (+) derived embryos. SERa (+) derived embryo can be selected as embryos for transfer when no available SERa (-) derived embryos.
Trial registration number
Not Applicable
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Affiliation(s)
- A Arichi
- Denentoshi Ladies Clinic, ART labo , yokohama, Japan
| | - T Yorimitu
- Denentoshi Ladies Clinic, reproductive medicine , yokohama, Japan
| | - N Omura
- Denentoshi Ladies Clinic, ART labo , yokohama, Japan
| | - K Ito
- Denentoshi Ladies Clinic, ART labo , yokohama, Japan
| | - H Komine
- Denentoshi Ladies Clinic, ART labo , yokohama, Japan
| | - Y Kudo
- Denentoshi Ladies Clinic, ART labo , yokohama, Japan
| | - Y Shimizu
- Denentoshi Ladies Clinic, reproductive medicine , yokohama, Japan
| | - T Kawamura
- Denentoshi Ladies Clinic, reproductive medicine , yokohama, Japan
| | - M Ohara
- Denentoshi Ladies Clinic, reproductive medicine , yokohama, Japan
| | - H Sasaki
- Denentoshi Ladies Clinic, reproductive medicine , yokohama, Japan
| | - S Honma
- Denentoshi Ladies Clinic, reproductive medicine , yokohama, Japan
| | - M Hasui
- Denentoshi Ladies Clinic, reproductive medicine , yokohama, Japan
| | - Y Takemura
- Denentoshi Ladies Clinic, reproductive medicine , yokohama, Japan
| | - K Teraoka
- Denentoshi Ladies Clinic, reproductive medicine , yokohama, Japan
| | - T Ishikawa
- tokyo medical and dental univ, Perinatal and maternal medicine , tokyo, Japan
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Asahara R, Ishii K, Izaki T, Iwaki S, Komine H. Blood pressure changes induced by cognitive task influence BOLD signal changes in the human brain. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.01504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ryota Asahara
- National Institute of Advanced Industrial Science and TechnologyTsukuba
| | - Kei Ishii
- National Institute of Advanced Industrial Science and TechnologyTsukuba
| | - Tsubasa Izaki
- National Institute of Advanced Industrial Science and TechnologyTsukuba
| | - Sunao Iwaki
- National Institute of Advanced Industrial Science and TechnologyTsukuba
| | - Hidehiko Komine
- National Institute of Advanced Industrial Science and TechnologyTsukuba
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Ishii K, Asahara R, Komine H, Liang N, Matsukawa K. Contribution of the ventral tegmental area to spontaneous coactivation of the motor and cardiovascular systems in decerebrate rats. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.05032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Asahara R, Ishii K, Izaki T, Iwaki S, Komine H. Internal carotid artery blood flow response to cognitive task is similar between young and older adults. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.09955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ryota Asahara
- National Institute of Advanced Industrial Science and Technology
| | - Kei Ishii
- National Institute of Advanced Industrial Science and Technology
| | - Tsubasa Izaki
- National Institute of Advanced Industrial Science and Technology
| | - Sunao Iwaki
- National Institute of Advanced Industrial Science and Technology
| | - Hidehiko Komine
- National Institute of Advanced Industrial Science and Technology
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Ishii K, Asahara R, Komine H, Liang N, Matsukawa K. Pivotal role of the ventral tegmental area in spontaneous motor activity and concomitant cardiovascular responses in decerebrate rats. Brain Res 2020; 1729:146616. [DOI: 10.1016/j.brainres.2019.146616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/11/2019] [Accepted: 12/16/2019] [Indexed: 10/25/2022]
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Komine H, Fukasawa K, Akasaka M, Watari Y, Iwai N, Kaji K. Rapid behavioural responses of native frogs caused by past predation pressure from invasive mongooses. J Zool (1987) 2019. [DOI: 10.1111/jzo.12734] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- H. Komine
- Institute of Global Innovation Research Tokyo University of Agriculture and Technology Fuchu, Tokyo Japan
| | - K. Fukasawa
- Center for Environmental Biology and Ecosystem Studies National Institute for Environmental Studies Tsukuba Japan
| | - M. Akasaka
- Institute of Global Innovation Research Tokyo University of Agriculture and Technology Fuchu, Tokyo Japan
- Institute of Agriculture Tokyo University of Agriculture and Technology Fuchu, Tokyo Japan
| | - Y. Watari
- Department of Wildlife Biology Forestry and Forest Products Research Institute Tsukuba Japan
| | - N. Iwai
- Institute of Global Innovation Research Tokyo University of Agriculture and Technology Fuchu, Tokyo Japan
- Institute of Agriculture Tokyo University of Agriculture and Technology Fuchu, Tokyo Japan
| | - K. Kaji
- Institute of Agriculture Tokyo University of Agriculture and Technology Fuchu, Tokyo Japan
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Machino T, Ishii K, Yamagami F, Komine H, Kitazaki S, Akamatsu M, Yamasaki H, Sekiguchi Y, Tsurushima H, Nogami A, Aonuma K. P4428Near-infrared spectroscopy demonstrated a heart rate-dependent decrease in cerebral oxygenation during paroxysmal supraventricular tachycardia as well as ventricular tachycardia. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy563.p4428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- T Machino
- University of Tsukuba, Tsukuba, Japan
| | - K Ishii
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | | | - H Komine
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - S Kitazaki
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - M Akamatsu
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | | | | | | | - A Nogami
- University of Tsukuba, Tsukuba, Japan
| | - K Aonuma
- University of Tsukuba, Tsukuba, Japan
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Komine H, Machino T, Yamagami F, Nogami A, Aonuma K, Tsurushima H, Ishii K, Hatori Y, Gwak J, Takahashi N, Kitazaki S, Akamatsu M. The effects of cardiac contraction on cerebral oxygenation during supraventricular and ventricular tachycardia. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.712.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Fumi Yamagami
- Cardiovascular DivisionUniversity of TsukubaTsukubaJapan
| | - Akihiko Nogami
- Cardiovascular DivisionUniversity of TsukubaTsukubaJapan
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Ishii K, Machino T, Yamagami F, Nogami A, Aonuma K, Tsurushima H, Hatori Y, Gwak J, Takahashi N, Komine H, Kitazaki S, Akamatsu M. Prefrontal and muscle oxygenation responses to supraventricular tachycardia. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.712.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kei Ishii
- Automotive Human Factors Research CenterNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | | | - Fumi Yamagami
- Cardiovascular DivisionUniversity of TsukubaTsukubaJapan
| | - Akihiko Nogami
- Cardiovascular DivisionUniversity of TsukubaTsukubaJapan
| | | | | | - Yasuhiro Hatori
- Automotive Human Factors Research CenterNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Jongseong Gwak
- Automotive Human Factors Research CenterNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Naoki Takahashi
- Automotive Human Factors Research CenterNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Hidehiko Komine
- Automotive Human Factors Research CenterNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Satoshi Kitazaki
- Automotive Human Factors Research CenterNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Motoyuki Akamatsu
- Automotive Human Factors Research CenterNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
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Komine H, Takeshita K, Abe S, Ishikawa T, Kimura M, Hashimoto T, Kitaura K, Morosawa T, Seki K, Kaji K. Relationships between capture-site characteristics and capture levels of the invasive mongoose on Amami-Oshima Island, Japan. Biol Invasions 2015. [DOI: 10.1007/s10530-015-1021-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Matsukawa K, Ishii K, Liang N, Endo K, Ohtani R, Nakamoto T, Wakasugi R, Kadowaki A, Komine H. Increased oxygenation of the cerebral prefrontal cortex prior to the onset of voluntary exercise in humans. J Appl Physiol (1985) 2015; 119:452-62. [DOI: 10.1152/japplphysiol.00406.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 07/10/2015] [Indexed: 11/22/2022] Open
Abstract
To determine whether output from the forebrain (termed central command) may descend early enough to increase cardiac and renal sympathetic outflows at the onset of voluntary exercise, we examined the changes in regional tissue blood flows of bilateral prefrontal cortices with near-infrared spectroscopy, precisely identifying the onset of voluntary ergometer 30-s exercise at 41 ± 2% of the maximal exercise intensity in humans. Prefrontal oxygenated-hemoglobin (Oxy-Hb) concentration was measured as index of regional blood flow unless deoxygenated-hemoglobin concentration remained unchanged. Prefrontal Oxy-Hb concentration increased significantly ( P < 0.05) 5 s prior to the onset of exercise with arbitrary start, whereas such increase in prefrontal Oxy-Hb was absent before exercise abruptly started by a verbal cue. Furthermore, the increase in prefrontal Oxy-Hb observed at the initial 15-s period of exercise was greater with arbitrary start than cued start. The prefrontal Oxy-Hb, thereafter, decreased during the later period of exercise, irrespective of either arbitrary or cued start. The reduction in prefrontal Oxy-Hb had the same time course and response magnitude as that during motor-driven passive exercise. Cardiac output increased at the initial period of exercise, whereas arterial blood pressure and total peripheral resistance decreased. The depressor response was more pronounced ( P < 0.05) with arbitrary start than cued start. Taken together, it is suggested that the increase in prefrontal Oxy-Hb observed prior to the onset of voluntary exercise may be in association with central command, while the later decrease in the Oxy-Hb during exercise may be in association with feedback stimulated by mechanical limb motion.
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Affiliation(s)
- Kanji Matsukawa
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and
| | - Kei Ishii
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and
| | - Nan Liang
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and
| | - Kana Endo
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and
| | - Ryo Ohtani
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and
| | - Tomoko Nakamoto
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and
| | - Rie Wakasugi
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and
| | - Akito Kadowaki
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and
| | - Hidehiko Komine
- Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
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Sugawara J, Komine H, Miyazawa T, Imai T, Ogoh S. Influence of regular exercise training on post-exercise hemodynamic regulation to orthostatic challenge. Front Physiol 2014; 5:229. [PMID: 25009503 PMCID: PMC4068294 DOI: 10.3389/fphys.2014.00229] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 06/02/2014] [Indexed: 01/10/2023] Open
Abstract
To prevent orthostatic hypotension, arterial blood pressure (BP) is neurally and hormonally regulated via increases in heart rate (HR) and peripheral vascular tone. After dynamic exercise, however, the latter arm is blunted because of the increased vasodilators in exercised muscles. Orthostatic tachycardia is likely a more important compensatory mechanism for post-exercise orthostatic intolerance in individuals who have higher leg vasodilator capacity, such as endurance-trained athletes. To test the hypothesis that regular endurance training was associated with the greater augmentation of tachycardia response to post-exercise orthostasis, we compared hemodynamic responses to 5-min 60° head-up tilt (HUT) before and after 60 min of cycling at 70% of HR reserve in the endurance-trained (n = 8) and sedentary men (n = 9). Calf peak vascular conductance was 62% greater in the endurance-trained than the sedentary (P < 0.001). After the exercise, the HUT-induced reduction of SV was significantly augmented in the endurance-trained (from −27.7 ± 6.9 to −33.7 ± 7.7 ml, P = 0.03) but not in their sedentary peers. Nevertheless, MAP was well maintained during post-exercise HUT even in the endurance-trained (from 81 ± 10 to 80 ± 8 mmHg). Tachycardia responses during sustained orthostasis were significantly increased in the sedentary (1.3-fold vs. pre-exercise) and more in the endurance-trained (2.0-fold). The augmented response of HUT-induced tachycardia was greater in the endurance-trained than the sedentary (P = 0.04). Additionally, cardiovagal baroreflex sensitivity (BRS), evaluated by the HR response to the hypotensive perturbation, was improved after the exercise in the endurance-trained (from −0.56 ± 0.32 to −1.03 ± 0.26 bpm/mmHg, P = 0.007) but not in the sedentary. These results suggest that in the endurance-trained men the increased orthostatic tachycardia and augmented cardiovagal BRS may favorably mitigate accumulated risks for orthostatic intolerance in the early phase of post-exercise.
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Affiliation(s)
- Jun Sugawara
- Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology Ibaraki, Japan
| | - Hidehiko Komine
- Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology Ibaraki, Japan
| | - Taiki Miyazawa
- Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology Ibaraki, Japan ; Department of Biomedical Engineering, Toyo University Kawagoe, Japan
| | - Tomoko Imai
- Graduate School of Comprehensive Human Sciences, University of Tsukuba Tsukuba, Japan
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University Kawagoe, Japan
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Sugawara J, Saito Y, Maeda S, Yoshizawa M, Komine H, Nakamura M, Ajisaka R, Tanaka H. Lack of changes in carotid artery compliance with systemic nitric oxide synthase inhibition. J Hum Hypertens 2014; 28:494-9. [PMID: 24401955 DOI: 10.1038/jhh.2013.137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 11/04/2013] [Accepted: 11/21/2013] [Indexed: 11/09/2022]
Abstract
Proximal large elastic arteries (ascending aorta and carotid artery) have an important role in buffering the pulsatile pressure generated from the left ventricle, which forwards continuous peripheral blood flow and protects the brain microcirculation from end-organ damage. Although compliance of distal conduit arteries (extremities' arteries) is attenuated by the nitric oxide synthase (NOS) inhibition, it is yet unknown whether compliance of proximal elastic arteries changes by the systemic NOS inhibition. To address this question, we measured central artery compliance in 17 young adults (26±1 years) who underwent intravenous infusions of N(G)-monomethyl-L-arginine (L-NMMA) or saline (placebo) on separate days. Following the systemic NOS inhibition, the mean arterial pressure (MAP), total peripheral resistance and aortic augmentation index were significantly increased. However, carotid artery compliance was not affected significantly (from 0.10±0.01 to 0.11±0.01 mm2) per mmHg) and the β-stiffness index (an index of arterial compliance adjusted for the distending pressure) tended to decrease (from 6.63±0.35 to 6.06±0.42 a.u., P=0.07). These parameters were not altered with saline infusion. Changes in the β-stiffness index tended to correlate negatively with the corresponding changes in MAP (r = -0.31, P=0.07). These results suggest that carotid artery compliance remains unchanged during the systemic NOS inhibition in spite of systemic vasoconstriction.
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Affiliation(s)
- J Sugawara
- 1] Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan [2] Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, TX, USA
| | - Y Saito
- Graduate School of Comprehensive Human Sciences, The University of Tsukuba, Tsukuba, Japan
| | - S Maeda
- Graduate School of Comprehensive Human Sciences, The University of Tsukuba, Tsukuba, Japan
| | - M Yoshizawa
- 1] Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan [2] Graduate School of Comprehensive Human Sciences, The University of Tsukuba, Tsukuba, Japan
| | - H Komine
- Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - M Nakamura
- Graduate School of Comprehensive Human Sciences, The University of Tsukuba, Tsukuba, Japan
| | - R Ajisaka
- Graduate School of Comprehensive Human Sciences, The University of Tsukuba, Tsukuba, Japan
| | - H Tanaka
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, TX, USA
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Miyazawa T, Horiuchi M, Komine H, Sugawara J, Fadel PJ, Ogoh S. Skin blood flow influences cerebral oxygenation measured by near-infrared spectroscopy during dynamic exercise. Eur J Appl Physiol 2013; 113:2841-8. [DOI: 10.1007/s00421-013-2723-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 09/03/2013] [Indexed: 10/26/2022]
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17
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Sugawara J, Komine H, Miyazawa T, Imai T, Ogoh S. Influence of regular endurance training on postexercise hemodynamic regulation to orthostatic challenge. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1149.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jun Sugawara
- Human Technology Research InstituteNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Hidehiko Komine
- Human Technology Research InstituteNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Taiki Miyazawa
- Human Technology Research InstituteNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
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Murata J, Matsukawa K, Komine H, Tsuchimochi H. Modulation of radial blood flow during Braille character discrimination task. Acta Physiol Hung 2012; 99:25-32. [PMID: 22425805 DOI: 10.1556/aphysiol.99.2012.1.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE Human hands are excellent in performing sensory and motor function. We have hypothesized that blood flow of the hand is dynamically regulated by sympathetic outflow during concentrated finger perception. To identify this hypothesis, we measured radial blood flow (RBF), radial vascular conductance (RVC), heart rate (HR), and arterial blood pressure (AP) during Braille reading performed under the blind condition in nine healthy subjects. The subjects were instructed to read a flat plate with raised letters (Braille reading) for 30 s by the forefinger, and to touch a blank plate as control for the Braille discrimination procedure. RESULTS HR and AP slightly increased during Braille reading but remained unchanged during the touching of the blank plate. RBF and RVC were reduced during the Braille character discrimination task (decreased by -46% and -49%, respectively). Furthermore, the changes in RBF and RVC were much greater during the Braille character discrimination task than during the touching of the blank plate (decreased by -20% and -20%, respectively). CONCLUSIONS These results have suggested that the distribution of blood flow to the hand is modulated via sympathetic nerve activity during concentrated finger perception.
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Affiliation(s)
- Jun Murata
- Nagasaki University Department of Physical and Occupational Therapy, Graduate School of Biomedical Sciences 1-7-1 Sakamoto Nagasaki 852-8520 Japan.
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Sugawara J, Komine H, Miyazawa T, Imai T, Fisher JP, Ogoh S. Impact of chronic exercise training on the blood pressure response to orthostatic stimulation. J Appl Physiol (1985) 2012; 112:1891-6. [PMID: 22422799 DOI: 10.1152/japplphysiol.01460.2011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exercise training elicits morphological adaptations in the left ventricle (LV) and large-conduit arteries that are specific to the type of training performed (i.e., endurance vs. resistance exercise). We investigated whether the mode of chronic exercise training, and the associated cardiovascular adaptations, influence the blood pressure responses to orthostatic stimulation in 30 young healthy men (10 sedentary, 10 endurance trained, and 10 resistance trained). The endurance-trained group had a significantly larger LV end-diastolic volume normalized by body surface area (vs. sedentary and resistance-trained groups), whereas the resistance-trained group had a significantly higher LV wall thickness and aortic pulse wave velocity (PWV) compared with the endurance-trained group. In response to 60° head-up tilt (HUT), mean arterial pressure (MAP) rose in the resistance-trained group (+6.5 ± 1.6 mmHg, P < 0.05) but did not change significantly in sedentary and the endurance-trained groups. Systolic blood pressure (SBP) decreased in endurance-trained group (-8.3 ± 2.4 mmHg, P < 0.05) but did not significantly change in sedentary and resistance-trained groups. A forward stepwise multiple regression analysis revealed that LV wall thickness and aortic PWV were significantly and independently associated with the MAP response to HUT, explaining ∼41% of its variability (R(2) =0.414, P < 0.001). Likewise, aortic PWV and the corresponding HUT-mediated change in stroke volume were significantly and independently associated with the SBP response to HUT, explaining ∼52% of its variability (R(2) = 0.519, P < 0.0001). Furthermore, the change in stroke volume significantly correlated with LV wall thickness (r = 0.39, P < 0.01). These results indicate that chronic resistance and endurance exercise training differentially affect the BP response to HUT, and that this appears to be associated with training-induced morphological adaptations of the LV and large-conduit arteries.
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Affiliation(s)
- Jun Sugawara
- Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan.
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20
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Komine H, Asai Y, Yokoi T, Yoshizawa M. Non-invasive assessment of arterial stiffness using oscillometric blood pressure measurement. Biomed Eng Online 2012; 11:6. [PMID: 22325084 PMCID: PMC3359259 DOI: 10.1186/1475-925x-11-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 02/10/2012] [Indexed: 01/11/2023] Open
Abstract
Background Arterial stiffness is a major contributor to cardiovascular diseases. Because current methods of measuring arterial stiffness are technically demanding, the purpose of this study was to develop a simple method of evaluating arterial stiffness using oscillometric blood pressure measurement. Methods Blood pressure was conventionally measured in the left upper arm of 173 individuals using an inflatable cuff. Using the time series of occlusive cuff pressure and the amplitudes of pulse oscillations, we calculated local slopes of the curve between the decreasing cuff pressure and corresponding arterial volume. Whole pressure-volume curve was derived from numerical integration of the local slopes. The curve was fitted using an equation and we identified a numerical coefficient of the equation as an index of arterial stiffness (Arterial Pressure-volume Index, API). We also measured brachial-ankle (baPWV) PWV and carotid-femoral (cfPWV) PWV using a vascular testing device and compared the values with API. Furthermore, we assessed carotid arterial compliance using ultrasound images to compare with API. Results The slope of the calculated pressure-volume curve was steeper for compliant (low baPWV or cfPWV) than stiff (high baPWV or cfPWV) arteries. API was related to baPWV (r = -0.53, P < 0.05), cfPWV (r = -0.49, P < 0.05), and carotid arterial compliance (r = 0.32, P < 0.05). A stepwise multiple regression analysis demonstrated that baPWV and carotid arterial compliance were the independent determinants of API, and that API was the independent determinant of baPWV and carotid arterial compliance. Conclusions These results suggest that our method can simply and simultaneously evaluate arterial stiffness and blood pressure based on oscillometric measurements of blood pressure.
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Affiliation(s)
- Hidehiko Komine
- Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan.
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Sugawara J, Willie CK, Miyazawa T, Komine H, Ainsle PN, Ogoh S. Effects of transient change in carotid arterial stiffness on arterial baroreflex during mild orthostatic stimulation. Artery Res 2012. [DOI: 10.1016/j.artres.2012.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Choi Y, Maeda S, Yoshizawa M, Tanabe K, Miyaki A, Tanabe Y, Komine H, Hirayama A, Shiraki H, Ajisaka R. High circulating levels of oxidized LDL in strength-trained athletes. J Exerc Nutrition Biochem 2011. [DOI: 10.5717/jenb.2011.15.2.105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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23
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Sugawara J, Komine H, Miyazawa T, Imai T, Ogoh S. Influences of Regular Resistance Training on Postexercise Hypotension. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000401254.45090.53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Komine H, Yoshizawa M, Maeda S, Shimojo N, Takai Y, Akazawa N, Yokoi T. The effects of regular endurance exercise on IL‐6 and the sympathetic nervous system. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1056.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Mutsuko Yoshizawa
- Division of Sports MedicineGraduate School of Comprehensive Human Sciences
| | - Seiji Maeda
- Division of Sports MedicineGraduate School of Comprehensive Human Sciences
| | - Nobutake Shimojo
- Division of Cardiovascular MedicineGraduate School of Comprehensive Human SciencesUniversity of TsukubaTsukubaJapan
| | - Yohei Takai
- Human Technology Research InstituteAISTTsukubaJapan
| | - Nobuhiko Akazawa
- Division of Sports MedicineGraduate School of Comprehensive Human Sciences
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Yoshizawa M, Maeda S, Choi Y, Shimojo N, Komine H. Circulating endothelial progenitor cells in strength‐trained men. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1056.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Mutsuko Yoshizawa
- Division of Sports MedicineGraduate School of Comprehensive Human Sciences
- University of ColoradoBoulderCO
| | - Seiji Maeda
- Division of Sports MedicineGraduate School of Comprehensive Human Sciences
| | - Youngju Choi
- Division of Sports MedicineGraduate School of Comprehensive Human Sciences
| | - Nobutake Shimojo
- Division of Cardiovascular MedicineGraduate School of Comprehensive Human SciencesUniversity of TsukubaTsukubaJapan
| | - Hidehiko Komine
- Human Technology Research InstituteNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
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Oyama K, Onuki T, Kanzaki M, Isaka T, Kikkawa T, Shimizu T, Sakamoto K, Komine H, Murasugi M. [Video-assisted thoracic surgery for pneumothorax in patients over fifty years of age]. Kyobu Geka 2011; 64:275-279. [PMID: 21491720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
BACKGROUND Pneumothorax in middle-aged and elderly patients has various different features from young patients. We set out to investigate the outcome and usefulness of video-assisted thoracic surgery (VATS) in this group. PATIENTS AND METHODS From January 1993 to August 2010, 168 patients underwent a total of 178 thoracoscopic surgeries. There were 160 men and 8 women with mean age of 67 (range, 50 to 85). The average duration of thoracic drainage before surgery was 7.4 days. We excised only responsible lesions as minimum degree of dissection as possible. When patients have intractable air leakage and chest computed tomography (CT) indicates severe pleural adhesions, pleurography should be performed to locate the site of air leakage and determine surgical approaches. One hundred and seventy patients were treated with the lateral approach, while 8 patients were successfully treated with the anterior approach. One hundred and fifty-one patients were treated with VATS alone, and 27 patients were treated with the combination of VATS and small thoracotomy. The duration of chest tube drainage, hospital stay, post-operative complication, outcome and recurrence were assessed. RESULTS The air leakages stopped and all patients except for 2 patents were discharged without drainage tubes. Postoperative drainage time was 4.5 +/- 3.4 days. Postoperative hospital stay was 9.9 +/- 13.9 days. One patient died caused by perioperative myocardial infarction. Seventeen patients died of other diseases. Seven patients needed local hospital treatments and the recurrence rate was 3.9%. CONCLUSION VATS for pneumothorax in patients over 50 years old is very useful by appropriate perioperative managements.
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Affiliation(s)
- K Oyama
- Department of Surgery I, Tokyo Women's Medical University, Tokyo, Japan
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Komine H, Takai Y, Akazawa N, Maeda S, Yoshizawa M, Sugawara J, Yokoi T. Effects of regular endurance exercise on brachial blood flow response to mental stress. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.804.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Hidehiko Komine
- Institute for Human Science and Biomedical EngineeringNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Yohei Takai
- Institute for Human Science and Biomedical EngineeringNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Nobuhiko Akazawa
- Institute for Human Science and Biomedical EngineeringNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Seiji Maeda
- Division of Sports MedicineGraduate School of Comprehensive Human SciencesUniversity of TsukubaTsukubaJapan
| | - Mutsuko Yoshizawa
- Division of Sports MedicineGraduate School of Comprehensive Human SciencesUniversity of TsukubaTsukubaJapan
| | - Jun Sugawara
- Institute for Human Science and Biomedical EngineeringNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Takashi Yokoi
- Institute for Human Science and Biomedical EngineeringNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
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Komine H, Shinomori K, Nakauchi S. Representation of color naming category boundaries on dichromats along their confusion loci using a chromatic-opponent channel model. J Vis 2010. [DOI: 10.1167/9.8.321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Sugawara J, Komine H, Yoshiwaza M, Tarumi T, Maeda S, Tanaka H. Racial Differences in Relation Between Carotid and Radial Augmentation Index. Artery Res 2010; 4:15-18. [PMID: 20419062 DOI: 10.1016/j.artres.2009.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND: Augmented central artery wave reflection is a cardiovascular disease risk factor. Augmentation index (AI) obtained from peripheral artery waveforms provides qualitatively similar information to AI from central artery waveforms. Little information is available, however, regarding the influence of racial difference in association between central and peripheral AI. METHODS: We studied 47 White adults (45+/-17 yr, 20 women) and 94 age-matched Asian adults (45+/-14 yr, 42 women). RESULTS: The White group was significantly taller than the Asian group, whereas there were no significant group differences in blood pressure and heart rate. Carotid and radial AI tended to be lower in White compared with Asian adults (P<0.10 for both). Such tendency disappeared when the difference in height was taken into account using ANCOVA (P=0.84 and P=0.77, respectively). Radial AI was strongly and positively correlated with carotid AI in White adults (r=0.75, P<0.0001) as well as in Asian adults (r=0.82, P<0.0001). The slope and intercept of linear regression line between radial and carotid AI of White adults were highly comparable with those of Asian adults. CONCLUSION: AI in the conveniently located peripheral vasculature may provide a surrogate measure of central AI irrespective of difference in race (e.g., Asian vs. White populations).
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Affiliation(s)
- Jun Sugawara
- Institute for Human Science and Biomedical Engineering, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan
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Komine H, Sugawara J, Hayashi K, Yoshizawa M, Yokoi T. Regular endurance exercise in young men increases arterial baroreflex sensitivity through neural alteration of baroreflex arc. J Appl Physiol (1985) 2009; 106:1499-505. [DOI: 10.1152/japplphysiol.91447.2008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Endurance exercise training increases arterial baroreflex sensitivity that corresponds to alteration in vessel wall compliance of the carotid artery in elderly men. Here, we examined whether regular endurance exercise increases arterial baroreflex sensitivity through neural alteration of the baroreflex arc in young men. We assessed arterial baroreflex sensitivity in eight sedentary men (age 24 ± 1 yr) and nine men trained in endurance exercise (age 23 ± 1 yr) during phase IV of the Valsalva maneuver [systolic arterial blood pressure (SAP)–R-R interval relationship]. Arterial baroreflex sensitivity was further analyzed by dividing the mechanical component [SAP–end-systolic carotid lumen diameter relationship (ultrasonography)] and the neural component (end-systolic carotid lumen diameter–R-R interval relationship). Carotid arterial compliance was determined using B-mode ultrasound and arterial applanation tonometry on the common carotid artery. Arterial baroreflex sensitivity and its neural component were greater in the exercise-trained group ( P < 0.05). In contrast, carotid arterial compliance and the mechanical component of arterial baroreflex sensitivity did not differ between groups. These results suggest that regular endurance exercise in young men increases arterial baroreflex sensitivity through changes in the neural component of the baroreflex arc and not through alterations in vessel wall compliance of the carotid artery.
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Komine H, Matsukawa K, Tsuchimochi H, Nakamoto T, Murata J. Sympathetic cholinergic nerve contributes to increased muscle blood flow at the onset of voluntary static exercise in conscious cats. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1251-62. [PMID: 18703415 DOI: 10.1152/ajpregu.00076.2008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined whether a sympathetic cholinergic mechanism contributed to increased blood flow of the exercising muscle at the onset of voluntary static exercise in conscious cats. After six cats were operantly conditioned to perform static bar press exercise with a forelimb while maintaining a sitting posture, a Transonic or pulsed Doppler flow probe was implanted on the brachial artery of the exercising forelimb, and catheters were inserted into the left carotid artery and jugular vein. After the baseline brachial blood flow and vascular conductance decreased and became stable in progress of postoperative recovery, the static exercise experiments were started. Brachial blood flow and vascular conductance began to increase simultaneously with the onset of exercise. Their initial increases reached 52 +/- 8% and 40 +/- 6% at 3 s from the exercise onset, respectively. Both a sympathetic ganglionic blocker (hexamethonium bromide) and atropine sulfate or methyl nitrate blunted the increase in brachial vascular conductance at the onset of static exercise, whereas an inhibitor of nitric oxide synthesis (N(omega)-nitro-l-arginine methyl ester) did not alter the increase in brachial vascular resistance. Brachial blood flow and vascular conductance increased during natural grooming behavior with the forelimb in which the flow probe was implanted, whereas they decreased during grooming with the opposite forelimb and during eating behavior. Thus it is likely that the sympathetic cholinergic mechanism is capable of evoking muscle vasodilatation at the onset of voluntary static exercise in conscious cats.
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Affiliation(s)
- Hidehiko Komine
- Dept. of Physiology, Graduate School of Health Sciences, Hiroshima Univ., Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551, Japan
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Hayashi K, Sugawara J, Aizawa K, Komine H, Yoshizawa M, Nakamura M, Yokoi T. Arterial elastic property in young endurance and resistance-trained women. Eur J Appl Physiol 2008; 104:763-8. [PMID: 18649085 DOI: 10.1007/s00421-008-0829-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2008] [Indexed: 11/29/2022]
Abstract
In men, regular aerobic exercise increases central arterial elasticity, but it is decreased by resistance training. We determined the relation between the type of exercise training and arterial elasticity in healthy young women: 26 healthy young women who were sedentary (CO, n = 9), endurance-trained (ET, n = 9), and resistance-trained (RT, n = 8) groups. We determined the carotid arterial compliance and distensibility coefficient (simultaneous ultrasound and applanation tonometry), VO(2max), and 1RM (bench press and leg extension). The VO(2max) in the ET groups was higher than in the CO and RT groups. Both 1RM were higher in the RT groups than in the CO and ET groups. No significant difference was found in the carotid artery compliance and distensibility coefficient among the ET, RT, and CO groups. These results underscore the difficulty in detecting a change in arterial elasticity in young female athletes using the type of exercise training by which it is shown in young men.
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Affiliation(s)
- Koichiro Hayashi
- Department of Music, Sapporo Otani University, 1-1 Kita 16 Higashi 9, Higashiku, Sapporo, Hokkaido 065-8567, Japan.
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Sugawara J, Komine H, Hayashi K, Yoshizawa M, Otsuki T, Shimojo N, Miyauchi T, Yokoi T, Maeda S, Tanaka H. Reduction in alpha-adrenergic receptor-mediated vascular tone contributes to improved arterial compliance with endurance training. Int J Cardiol 2008; 135:346-52. [PMID: 18603318 DOI: 10.1016/j.ijcard.2008.04.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Accepted: 04/01/2008] [Indexed: 11/28/2022]
Abstract
BACKGROUND Regular aerobic exercise improves large artery compliance in middle-aged and older humans. However, the underlying mechanisms are unknown. We tested the hypothesis that the improved central arterial compliance with endurance training is mediated by decreased alpha-adrenergic tone and/or increased endothelial function. METHODS Seven sedentary healthy adults (60+/-3 years) underwent systemic alpha-adrenergic blockade (phentolamine) and nitric oxide synthase (NOS) inhibition using N(G)-monomethyl-L-arginine in sequence before and after a 3-month moderate endurance training (walk/jog, 4-5 days/week). Phentolamine was given first to isolate the contribution of nitric oxide to arterial compliance by minimizing reflex suppression of sympathetic tone resulting from systemic NOS inhibition as well as to assess the alpha-adrenergic receptor-mediated modulation of arterial compliance. RESULTS Baseline arterial compliance (via simultaneous ultrasound and applanation tonometry on the carotid artery) increased 34+/-12% after exercise training (P<0.01). When alpha-adrenergic blockade was performed, arterial compliance increased 37+/-6% (P<0.01) before the exercise training but did not change significantly after the training. Decreases in arterial compliance from the alpha-adrenergic blockade to the subsequent additional NOS blockade were not different before and after exercise training. CONCLUSION Our results suggest that the reduction in alpha-adrenergic receptor-mediated vascular tone contributes to the improved central arterial compliance with endurance training.
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Affiliation(s)
- Jun Sugawara
- Institute for Human Science and Biomedical Engineering, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan.
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Sugawara J, Komine H, Hayashi K, Yoshizawa M, Otsuki T, Shimojo N, Miyauchi T, Yokoi T, Maeda S, Tanaka H. Reduction in Alpha-Adrenergic Receptor-Mediated Vascular Tone Contributes to Improved Arterial Compliance with Endurance Training. Med Sci Sports Exerc 2008. [DOI: 10.1249/01.mss.0000321494.45721.c1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Sugawara J, Komine H, Yoshizawa M, Saito Y, Nakamura M, Ajisaka R, Maeda S, Tanaka H. Carotid artery compliance and systemic nitric oxide synthase inhibition in young healthy adults. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.1154.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jun Sugawara
- Department of Kinesiology and Health EducationUniversity of Texas at AustinAustinTX
- National Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Hidehiko Komine
- National Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Mitsuko Yoshizawa
- National Institute of Advanced Industrial Science and TechnologyTsukubaJapan
- University of TsukubaTsukubaJapan
| | | | - Mariko Nakamura
- National Institute of Advanced Industrial Science and TechnologyTsukubaJapan
- University of TsukubaTsukubaJapan
| | | | | | - Hirofumi Tanaka
- Department of Kinesiology and Health EducationUniversity of Texas at AustinAustinTX
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Komine H, Sugawara J, Hayashi K, Yoshizawa M, Yokoi T. Differential effect of aerobic exercise training on cardiovagal baroreflex and carotid arterial compliance. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.957.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Hidehiko Komine
- National Institute of dvanced Industrial Science and TechnologyTsukubaIbarakiJapan
| | - Jun Sugawara
- National Institute of dvanced Industrial Science and TechnologyTsukubaIbarakiJapan
| | - Koichiro Hayashi
- National Institute of dvanced Industrial Science and TechnologyTsukubaIbarakiJapan
| | - Mutsuko Yoshizawa
- National Institute of dvanced Industrial Science and TechnologyTsukubaIbarakiJapan
| | - Takashi Yokoi
- National Institute of dvanced Industrial Science and TechnologyTsukubaIbarakiJapan
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Sugawara J, Komine H, Hayashi K, Yoshizawa M, Yokoi T, Otsuki T, Shimojo N, Miyauchi T, Maeda S, Tanaka H. Effect of systemic nitric oxide synthase inhibition on arterial stiffness in humans. Hypertens Res 2007; 30:411-5. [PMID: 17587753 DOI: 10.1291/hypres.30.411] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Stiffening of large elastic arteries impairs the buffering function of the arterial system and contributes to cardiovascular disease. The aim of this study was to determine whether endothelium-derived nitric oxide (NO) modulates the stiffness of large elastic arteries in humans. Seven apparently healthy adults (60+/-3 years, 2 males and 5 females) underwent systemic alpha-adrenergic blockade (phentolamine) and systemic NO synthase inhibition using NG-monomethyl-L-arginine (L-NMMA) in sequence. Phentolamine was given first to isolate contribution of NO to arterial stiffness by preventing reflex changes in sympathetic tone that result from systemic NO synthase inhibition, and also to compare arterial stiffness at a similar mean arterial pressure. Mean arterial blood pressure decreased (p<0.05) after phentolamine infusion but returned to baseline levels after L-NMMA infusion. The carotid beta-stiffness index (via simultaneous ultrasound and applanation tonometry on the common carotid artery) did not change after the restraint of systemic alpha-adrenergic nerve activity (9.8+/-1.2 vs. 9.1+/-1.1 U) but increased (p<0.05) after NO synthase inhibition (12.6+/-2.0 U). These results suggest that NO appears to modulate central arterial stiffness in humans.
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Affiliation(s)
- Jun Sugawara
- Institute for Human Science and Biomedical Engineering, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.
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Sugawara J, Komine H, Hayashi K, Yoshizawa M, Otsuki T, Shimojo N, Miyauchi T, Yokoi T, Maeda S, Tanaka H. Systemic alpha-adrenergic and nitric oxide inhibition on basal limb blood flow: effects of endurance training in middle-aged and older adults. Am J Physiol Heart Circ Physiol 2007; 293:H1466-72. [PMID: 17496216 DOI: 10.1152/ajpheart.00273.2007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Endurance training improves endothelium-dependent vasodilation, yet it does not increase basal blood flow in the legs. We determined the effects of a 3-mo aerobic exercise intervention on basal leg blood flow and alpha-adrenergic vasoconstriction and nitric oxide (NO) release in seven apparently healthy middle-aged and older adults (60 +/- 3 yr). Basal femoral artery blood flow (via Doppler ultrasound) (pretraining: 354 +/- 29; posttraining: 335 +/- 34 ml/min) and vascular conductance did not change significantly with the exercise training. Before the exercise intervention, femoral artery blood flow increased 32 +/- 16% with systemic alpha-adrenergic blockade (with phentolamine) (P < 0.05), and the addition of nitric oxide synthase (NOS) inhibition using N(G)-monomethyl-L-arginine (L-NMMA) did not affect femoral artery blood flow. After training was completed, femoral artery blood flow increased 47 +/- 7% with alpha-adrenergic blockade (P < 0.01) and then decreased 18 +/- 7% with the subsequent administration of L-NMMA (P < 0.05). Leg vascular conductance showed a greater alpha-adrenergic blockade-induced vasodilation (+1.7 +/- 0.5 to +3.0 +/- 0.5 units, P < 0.05) as well as NOS inhibition-induced vasoconstriction (-0.8 +/- 0.4 to -2.7 +/- 0.7 units, P < 0.05) after the exercise intervention. Resting plasma norepinephrine concentration significantly increased after the training. These results suggest that regular aerobic exercise training enhances NO bioavailability in middle-aged and older adults and that basal limb blood flow does not change with exercise training because of the contrasting influences of sympathetic nervous system activity and endothelium-derived vasodilation on the vasculature.
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Affiliation(s)
- Jun Sugawara
- Institute for Human Science and Biomedical Engineering, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan.
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Sugawara J, Komine H, Hayashi K, Yoshizawa M, Otsuki T, Shimojo N, Miyauchi T, Yokoi T, Maeda S, Tanaka H. Systemic α-adrenergic and Nitric Oxide Inhibition on Basal Limb Blood Flow before and after Endurance Training in Aging Humans. Med Sci Sports Exerc 2007. [DOI: 10.1249/01.mss.0000272950.43068.53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
OBJECTIVE Increased aortic and carotid arterial augmentation index (AI) has been directly linked with cardiovascular disease risk, mortality and morbidity. The aim of this study was to examine whether AI obtained directly from radial artery pressure waveforms (radial AI) can provide information comparable with carotid arterial AI measurements. METHODS In a cross-sectional study of 204 apparently healthy subjects (88 men and 116 women) aged 19-76 years (51 +/- 15 years, mean +/- SD), carotid AI [(second peak carotid systolic pressure - first peak carotid systolic pressure)/carotid pulse pressure*100] and radial AI [(second peak radial systolic pressure - diastolic pressure)/(first peak radial systolic pressure - diastolic pressure)*100] were measured using applanation tonometry. RESULTS Radial AI was strongly correlated with carotid AI (r = 0.86, P < 0.0001, SD of difference 10.0%), although radial AI was consistently approximately 66% higher than carotid AI. In 16 apparently healthy young adults (11 men and five women, aged 23 +/- 3 years) handgrip exercise was immediately followed by post-exercise muscle ischaemia (PEMI) to compare changes in carotid and radial AI during increased sympathetic nervous activity. PEMI caused parallel increases in carotid and radial AI (26 and 19%). Accordingly, changes in radial AI with PEMI were strongly correlated with corresponding changes in carotid AI (r = 0.86, P < 0.0001, SD of difference 7.3%). CONCLUSION These results suggest that AI obtained directly from radial arterial pressure waveforms could provide equivalent information to carotid arterial AI, and has potential as a surrogate marker of cardiovascular disease.
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Affiliation(s)
- Jun Sugawara
- Institute for Human Science and Bioengineering, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan.
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Sugawara J, Komine H, Hayashi K, Yoshizawa M, Yokoi T, Otsuki T, Shimojo N, Miyauchi T, Maeda S, Tanaka H. Effect of Systemic Nitric Oxide Synthase Inhibition on Arterial Stiffness in Humans. Med Sci Sports Exerc 2006. [DOI: 10.1249/00005768-200605001-01703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Goodno GD, Komine H, McNaught SJ, Weiss SB, Redmond S, Long W, Simpson R, Cheung EC, Howland D, Epp P, Weber M, McClellan M, Sollee J, Injeyan H. Coherent combination of high-power, zigzag slab lasers. Opt Lett 2006; 31:1247-9. [PMID: 16642074 DOI: 10.1364/ol.31.001247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We demonstrate a scalable architecture for a high-power, high-brightness, solid-state laser based on coherent combinations of master oscillator power amplifier chains. A common master oscillator injects a sequence of multikilowatt Nd:YAG zigzag slab amplifiers. Adaptive optics correct the wavefront of each amplified beamlet. The beamlets are tiled side by side and actively phase locked to form a single output beam. The laser produces 19 kW with beam quality <2x diffraction limited. To the best of our knowledge, this is the brightest cw solid-state laser demonstrated to date.
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Affiliation(s)
- G D Goodno
- Northrop Grumman Space Technology, California 90278, USA.
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Matsukawa K, Komine H, Nakamoto T, Murata J. Central command blunts sensitivity of arterial baroreceptor-heart rate reflex at onset of voluntary static exercise. Am J Physiol Heart Circ Physiol 2006; 290:H200-8. [PMID: 16113070 DOI: 10.1152/ajpheart.00013.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have reported that baroreflex bradycardia by stimulation of the aortic depressor nerve is blunted at the onset of voluntary static exercise in conscious cats. Central command may contribute to the blunted bradycardia, because the most blunted bradycardia occurs immediately before exercise or when a forelimb is extended before force development. However, it remained unknown whether the blunted bradycardia is due to either reduced sensitivity of the baroreflex stimulus-response curve or resetting of the curve toward a higher blood pressure. To determine this, we examined the stimulus-response relationship between systolic (SAP) or mean arterial pressure (MAP) and heart rate (HR) at the onset of and during the later period of static exercise in seven cats ( n = 348 trials) by changing arterial pressure with infusion of nitroprusside and phenylephrine or norepinephrine. The slope of the MAP-HR curve decreased at the onset of exercise to 48% of the preexercise value (2.9 ± 0.4 beats·min−1·mmHg−1); the slope of the SAP-HR curve decreased to 59%. The threshold blood pressures of the stimulus-response curves, at which HR started to fall due to arterial baroreflex, were not affected. In contrast, the slopes of the stimulus-response curves during the later period of exercise returned near the preexercise levels, whereas the threshold blood pressures elevated 6–8 mmHg. The maximal plateau level of HR was not different before and during static exercise, denying an upward shift of the baroreflex stimulus-response curves. Thus central command is likely to attenuate sensitivity of the cardiac component of arterial baroreflex at the onset of voluntary static exercise without shifting the stimulus-response curve.
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Affiliation(s)
- Kanji Matsukawa
- Dept. of Physiology, Graduate School of Health Sciences, Hiroshima Univ., Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551, Japan.
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Matsukawa K, Kobayashi T, Nakamoto T, Murata J, Komine H, Noso M. Noninvasive evaluation of cardiac output during postural change and exercise in humans: comparison between the modelflow and pulse dye-densitometry. ACTA ACUST UNITED AC 2005; 54:153-60. [PMID: 15182422 DOI: 10.2170/jjphysiol.54.153] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
To investigate whether the Model-flow method, by simulating the aortic input impedance model from a noninvasive monitoring of arterial blood pressure, reflected a reliable measure of cardiac output (CO) during postural change and whole-body exercise occurring in daily life, we compared the Modelflow-estimated CO with a simultaneous reference determined by the pulse dye-densitometry. Nine healthy volunteers performed postural change from supine to upright and dynamic stepping exercise. The Modelflow-estimated CO decreased to 4.8 +/- 0.5 l/min, from 5.8 +/- 0.6 l/min, during the postural change and increased to 12.8 +/- 1.3 l/min during a stepping exercise, returning to 5.1 +/- 0.4 l/min at 5 min after exercise. When comparing the pooled data of CO during resting and following exercise between the Modelflow and pulse dye-densitometry, we found that the average CO did not differ between the two estimates and that there was a significant correlation between them; the slope of the linear regression line corresponded to approximately 1.0. Although such linear relationship was also observed in an individual subject, the slope of the regression line varied from 0.737 to 1.588 among the subjects. The calibration of the Modelflow-estimated CO with the dye-densitometry value at supine or upright improved a correlation between the two estimates. Thus it is likely that the noninvasive Modelflow simulation from arterial blood pressure can provide a reliable estimation of group-average cardiac output during postural change and stepping exercise occurring in daily life. It will be recommended for a more accurate estimation of cardiac output in a given subject to calibrate the Modelflow data with an independent measure.
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Affiliation(s)
- K Matsukawa
- Department of Physiology, Graduate School of Health Sciences, Hiroshima University, Hiroshima, 734-8551 Japan.
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Hayashi K, Sugawara J, Komine H, Maeda S, Yokoi T. Effects of Aerobic Exercise Training on the Stiffness of Central and Peripheral Arteries in Middle-Aged Sedentary Men. ACTA ACUST UNITED AC 2005; 55:235-9. [PMID: 16248931 DOI: 10.2170/jjphysiol.s2116] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Accepted: 10/26/2005] [Indexed: 11/05/2022]
Abstract
Aortic pulse wave velocity (PWV) significantly decreased after 16 weeks of moderate-intensity exercise training (walking/jogging) in 17 sedentary middle-aged men, whereas leg PWV did not. These results suggest that in contrast with central arterial stiffness, peripheral arterial stiffness is difficult to change with aerobic exercise training.
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Affiliation(s)
- Koichiro Hayashi
- Institute for Human Science and Biomedical Engineering, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan.
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Abstract
A complex balance between extrinsic neural and intrinsic mechanisms is responsible for regulating atrioventricular (AV) conduction. We hypothesized that atrial excitation interval is shortened during dynamic exercise by extrinsic cardiac autonomic activity and that if AV conduction time responds inversely to fluctuation in atrial rhythm, ventricular excitation interval will be maintained at the predetermined cardiac cycle length. To examine such inverse relationship between PP interval and the subsequent change in PR interval (DeltaPR), we analyzed the beat-to-beat changes in PP, PR, and RR intervals during stair-stepping exercise for 10 min in 11 sedentary and 9 trained subjects. In the sedentary group, the average PR interval significantly shortened during exercise, in parallel with the reduction in the average PP and RR intervals. The variance of PP and RR intervals was also significantly decreased during exercise. The reduction in the variance of RR interval was, however, much greater than that of PP interval, implying that AV conduction time changes inversely to fluctuation in atrial excitation rhythm. Indeed, the variance of PR interval was augmented during exercise and there was a clear inverse relationship between PP and DeltaPR intervals. Although trained subjects were characterized by their lower heart rate response during dynamic exercise, the responses in the variability of PP, PR, and RR intervals were fundamentally identical with those in sedentary subjects. We conclude that the AV nodal mechanism that operates at a higher level of heart rate during dynamic exercise may cancel fluctuation in atrial excitation interval and keep ventricular excitation rhythm at the predetermined cardiac cycle length.
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Affiliation(s)
- Tomoko Nakamoto
- Department of Physiology, Graduate School of Health Sciences, Hiroshima University, Minami-ku, Hiroshima, 734-8551 Japan
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Murata J, Matsukawa K, Komine H, Tsuchimochi H, Nakamoto T. Central inhibition of the aortic baroreceptors-heart rate reflex at the onset of spontaneous muscle contraction. J Appl Physiol (1985) 2004; 97:1371-8. [PMID: 15180975 DOI: 10.1152/japplphysiol.00307.2004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Animals decerebrated at the precollicular-premammillary body level exhibit spontaneous locomotion without any artificial stimulation. Our laboratory reported that the cardiovascular and autonomic responses at the onset of spontaneous locomotor events are evoked by central command, generated from the caudal diencephalon and the brain stem (Matsukawa K, Murata J, and Wada T. Am J Physiol Heart Circ Physiol 275: H1115–H1121, 1998). In this study, we examined whether central command and/or a reflex resulting from muscle afferents modulates arterial baroreflex function using a decerebrate cat model. The baroreflex was evoked by stimulating the aortic depressor nerve (ADN) at the onset of spontaneous muscle contraction (to test the possible influence of central command) and during electrically evoked contraction or passive stretch (to test the possible influence of the muscle reflex). When the ADN was stimulated at rest, heart rate and arterial blood pressure decreased by 40 ± 2 beats/min and 11 ± 1 mmHg, respectively. The baroreflex bradycardia was attenuated to 55 ± 4% at the onset of spontaneous contraction. The attenuating effect on the baroreflex bradycardia was not observed at the onset and middle of electrically evoked contraction or passive stretch. The depressor response to ADN stimulation was identical among resting and any muscle interventions. The inhibition of the baroreflex bradycardia during spontaneous contraction was seen after β-adrenergic blockade but abolished by muscarinic blockade, suggesting that the bradycardia is mainly evoked through cardiac vagal outflow. We conclude that central command, produced within the caudal diencephalon and the brain stem, selectively inhibits the cardiac component, but not the vasomotor component, of the aortic baroreflex at the onset of spontaneous exercise.
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Affiliation(s)
- Jun Murata
- Dept. of Physiology, Graduate School of Health Sciences, Hiroshima Univ., Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551 Japan
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Takahashi M, Sakaguchi A, Matsukawa K, Komine H, Kawaguchi K, Onari K. Cardiovascular control during voluntary static exercise in humans with tetraplegia. J Appl Physiol (1985) 2004; 97:2077-82. [PMID: 15310746 DOI: 10.1152/japplphysiol.00546.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of the present study was 1) to investigate whether an increase in heart rate (HR) at the onset of voluntary static arm exercise in tetraplegic subjects was similar to that of normal subjects and 2) to identify how the cardiovascular adaptation during static exercise was disturbed by sympathetic decentralization. Mean arterial blood pressure (MAP) and HR were noninvasively recorded during static arm exercise at 35% of maximal voluntary contraction in six tetraplegic subjects who had complete cervical spinal cord injury (C(6)-C(7)). Stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) were estimated by using a Modelflow method simulating aortic input impedance from arterial blood pressure waveform. In tetraplegic subjects, the increase in HR at the onset of static exercise was blunted compared with age-matched control subjects, whereas the peak increase in HR at the end of exercise was similar between the two groups. CO increased during exercise with no or slight decrease in SV. MAP increased approximately one-third above the control pressor response but TPR did not rise at all throughout static exercise, indicating that the slight pressor response is determined by the increase in CO. We conclude that the cardiovascular adaptation during voluntary static arm exercise in tetraplegic subjects is mainly accomplished by increasing cardiac pump output according to the tachycardia, which is controlled by cardiac vagal outflow, and that sympathetic decentralization causes both absent peripheral vasoconstriction and a decreased capacity to increase HR, especially at the onset of exercise.
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Affiliation(s)
- Makoto Takahashi
- Department of Sports Medicine, Graduate School of Health Sciences, Hiroshima University, Minami-ku, Hiroshima 734-8551, Japan
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Komine H, Matsukawa K, Tsuchimochi H, Murata J. Central command blunts the baroreflex bradycardia to aortic nerve stimulation at the onset of voluntary static exercise in cats. Am J Physiol Heart Circ Physiol 2003; 285:H516-26. [PMID: 12860562 DOI: 10.1152/ajpheart.00013.2003] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To examine whether the central characteristics of the aortic baroreflex alter from moment to moment during static exercise, we identified the dynamic changes in the sizes of the bradycardia and depressor response evoked by stimulation of the aortic depressor nerve (ADN). Three conscious cats were trained to voluntarily extend the right forelimb and press a bar for 31 +/- 1 s with a peak force of 337 +/- 22 g while maintaining a sitting posture. The ADN stimulation-induced bradycardia was attenuated at the initial period of exercise (up to 8 s from the exercise onset) to 62 +/- 5% of the preexercise bradycardia and remained blunted until the end of exercise. The most blunted bradycardia was observed immediately before or when the forelimb was extended before force development. The baroreflex-induced bradycardia was suppressed again at cessation of exercise when the forelimb was retracted and recovered within a few seconds. In contrast, static exercise did not affect the ADN stimulation-induced depressor response. The ADN stimulation-induced bradycardia was also blunted at the beginning of naturally occurring body movement such as spontaneous postural change or grooming behavior. Thus it is likely that the central characteristics of the aortic baroreflex dynamically change from moment to moment during voluntary static exercise and during natural body movement and that particularly a central inhibition of the cardiac component of the aortic baroreflex is induced by central command at the onset of static exercise, whereas the central property of the vasomotor component of the baroreflex is preserved.
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Affiliation(s)
- Hidehiko Komine
- Dept. of Physiology, Institute of Health Sciences, Hiroshima University Faculty of Medicine, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551, Japan
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Komine H, Matsukawa K, Murata J, Tsuchimochi H, Shimizu K. Forelimb vasodilatation induced by hypothalamic stimulation is greatly mediated with nitric oxide in anesthetized cats. Jpn J Physiol 2003; 53:97-103. [PMID: 12877766 DOI: 10.2170/jjphysiol.53.97] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The aim of this study was to examine whether or not stimulation of the hypothalamic defense area is capable of inducing sympathetic vasodilatation of the forelimb vascular bed in anesthetized cats. When the hypothalamic defense area was electrically stimulated, brachial blood flow velocity (brachial BFV) and vascular conductance were increased as well as femoral BFV and vascular conductance. Brachial BFV and vascular conductance increased by 110-139% during hypothalamic stimulation. These increases were blunted to approximately one-fifth of the control responses following i.v. injection of a synthesis inhibitor of nitric oxide, N(omega)-nitro-L-arginine methyl ester (L-NAME). The attenuating effect of L-NAME on forelimb vasodilatation evoked by hypothalamic stimulation was greater than that on hindlimb vasodilatation. The combined administration of L-NAME and atropine sulfate eliminated nearly all of the increases in brachial BFV and vascular conductance during hypothalamic stimulation. From the present results, we conclude that stimulation of the hypothalamic defense area is able to induce neurogenic vasodilatation of the cat forelimb vascular bed, which is greatly mediated with a nitric oxide mechanism. The contribution of nitric oxide to neurogenic vasodilatation seems to be greater in the forelimbs than hindlimbs.
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Affiliation(s)
- Hidehiko Komine
- Department of Physiology, Institute of Health Sciences, Hiroshima University Faculty of Medicine, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551, Japan
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