34 results on '"Kawakami, Yasushi"'
Search Results
2. Using computed tomography fusion imaging as learning data for sonographer training in identification of left ventricular endocardial boundaries.
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Shiina, Yoshiki, Ishizu, Tomoko, Nesaki, Satomi, Nakajima, Hideki, Iida, Noriko, Kawamatsu, Naoto, Sato, Kimi, Yamamoto, Masayoshi, Machino-Ohtsuka, Tomoko, Ieda, Masaki, and Kawakami, Yasushi
- Abstract
We hypothesized that if computed tomography (CT) images were used as learning data, we could overcome volume underestimation by echocardiography, improving the accuracy of left ventricular (LV) volume measurements. We utilized a fusion imaging modality consisting of echocardiography with superimposed CT images for 37 consecutive patients to identify the endocardial boundary. We compared LV volumes obtained with and without CT learning trace-lines (TLs). Furthermore, 3D echocardiography was used to compare LV volumes obtained with and without CT learning for endocardial identification. The mean difference between the echocardiography and CT-derived LV volumes and the coefficient of variation were compared pre- and post-learning. Bland–Altman analysis was used to assess the differences in LV volume (mL) obtained from the 2D pre-learning TL and 3D post-learning TL. The post-learning TL was located closer to the epicardium than the pre-learning TL. This trend was particularly pronounced in the lateral and the anterior wall. The post-learning TL was along the inner side of the high echoic layer in the basal-lateral wall in the four-chamber view. CT fusion imaging determined that the difference in LV volume between 2D echocardiography and CT was small (−25.6 ± 14.4 mL before learning, −6.9 ± 11.5 mL after learning) and that CT learning improved the coefficient of variation (10.9 % before learning, 7.8 % after learning). Significant improvements were observed during 3D echocardiography; the difference in LV volume between 3D echocardiography and CT was slight (−20.5 ± 15.1 mL before learning, 3.8 ± 15.7 mL after learning), and the coefficient of variation improved (11.5 % before learning, 9.3 % after learning). Differences between the LV volumes obtained using CT and echocardiography either disappeared or were reduced after CT fusion imaging. Fusion imaging is useful in training regimens for accurate LV volume quantification using echocardiography and may contribute to quality control. [Display omitted] • Differences between volumes using computed tomography (CT) vs echocardiography reduced after CT learning. • CT fusion learning minimizes volume underestimation from echocardiography alone. • Coefficients of variation between sonographers decreased after CT learning. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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3. The determinants of plasma brain natriuretic peptide level in severe aortic valve stenosis patients undergoing transcatheter aortic valve implantation.
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Nakazawa, Naomi, Seo, Yoshihiro, Ishizu, Tomoko, Sato, Kimi, Yamamoto, Masayoshi, Machino-Ohtsuka, Tomoko, Hoshi, Tomoya, Sato, Akira, Kawakami, Yasushi, Ohte, Nobuyuki, and Ieda, Masaki
- Abstract
• In aortic valve stenosis (AS) patients referred for transcatheter aortic valve implantation, wall stress did not correlate with plasma B-type natriuretic peptide (BNP) level. • AS and heart failure severities determine plasma BNP level. • BNP release is associated with myocardial damage progression under preserved left ventricular ejection fraction. Brain or B-type natriuretic peptide (BNP) is an objective marker to diagnose the presence of heart failure (HF) and assess its severity. However, the determinants of serum BNP level in elderly patients with severe aortic valve stenosis (AS) referred for transcatheter aortic valve implantation (TAVI) have not been well investigated. We prospectively studied 106 AS patients who underwent TAVI. Cardiac catheterization, transesophageal echocardiography, and blood collection for plasma BNP level measurements were performed simultaneously just before the TAVI procedures. Ninety-nine patients (83.9±5.0 years, 33% male) were studied. The natural logarithm of BNP (lnBNP) level was 5.4±0.9 pg/mL. Significant correlations with lnBNP level were observed in: 1) the history of syncope, prior HF medication, and New York Heart Association class III or IV (R=0.255, p =0.011) (R=0.210, p =0.037) (R=0.402, p <0.001), 2) albumin and hemoglobin level (R=-0.289, p =0.004) (R=0.263, p =0.009), 3) Left ventricular (LV) ejection fraction and global longitudinal strain (LVGLS) (R=-0.338, p <0.001) (R=0.447, p <0.001), 4) LV end-diastolic volume index (EDVI), LV mass index, and left atrial volume index (R=0.280, p =0.005) (R=0.366, p <0.001) (R=0.337, p <0.001), 5) the catheter-measured pressure gradient across the aortic valve (AVPG) (R=0.365, p <0.001). Note that LV wall stress was not significantly correlated with lnBNP level. LVGLS, AVPG, hemoglobin level, and LVEDVI were independently correlated with ln BNP level (R=0.652, LVGLS; β=0.395, p <0.006, AVPG; β=0.291, p =0.001, hemoglobin level; β=-0.216, p =0.011, and LVEDVI; β=0.203, p =0.016, respectively). In severe AS patients candidate for TAVI, multiple factors, including the severities of AS and HF conditions and subclinical LV dysfunction determined by LVGLS affects plasma BNP level. [Display omitted] [ABSTRACT FROM AUTHOR]
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- 2021
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4. Left Ventricular Longitudinal Strain as a Marker for Point of No Return in Hypertensive Heart Failure Treatment
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Ishizu, Tomoko, Seo, Yoshihiro, Namekawa, Mikiko, Murakoshi, Nobuyuki, Ieda, Masaki, and Kawakami, Yasushi
- Abstract
There are currently no therapies that can improve prognosis in cases of heart failure (HF) with preserved ejection fraction (EF). We hypothesized that there is a point of no return after which no response to treatment is noted and that for the prevention of hypertensive HF this point may be determined by left ventricle (LV) strain, in the prevention of hypertensive HF. Here an angiotensin-converting enzyme inhibitor (ACE-I) was initiated based on myocardial strain imaging and its effects were determined in an animal model.
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- 2024
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5. Teneligliptin Prevents Cardiomyocyte Hypertrophy, Fibrosis, and Development of Hypertensive Heart Failure in Dahl Salt-Sensitive Rats.
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Yamamoto, Masayoshi, Ishizu, Tomoko, Seo, Yoshihiro, Suto, Yoshimi, Sai, Seika, Xu, Dongzhu, Murakoshi, Nobuyuki, Kimura, Taizo, Kawakami, Yasushi, and Aonuma, Kazutaka
- Abstract
Background: We investigated the effects of the dipeptidyl peptidase 4 inhibitor teneligliptin on cardiac function and hemodynamics during heart failure in hypertensive model rats.Methods and Results: Fifty-five male Dahl salt-sensitive rats were divided into 4 groups: control group (0.3% NaCl chow; n = 13), hypertension (HT) group (8% NaCl chow; n = 20), HT-early TNL group (8% NaCl chow and teneligliptin from 6 weeks; n = 10), and HT-late TNL group (8% NaCl chow and teneligliptin from 10 weeks; n = 12). Hemodynamic measurement and tissue analyses were performed at 18 weeks. In all of the HT groups, systolic blood pressures were similarly elevated (P = .66) and heart weights similarly increased (P = .36) with and without TNL administration. LV end-diastolic dimension was significantly enlarged only in the HT-early TNL group compared with the control group (P = .025). Histologic analysis showed less fibrosis (P = .008) and cardiomyocyte widths (P = .009) in the HT-early TNL group compared with the HT group. On hemodynamic analysis, only the HT group showed significant LV end-diastolic pressure elevation (P = .049) and lung congestion (P < .001) compared with the control group.Conclusions: These results suggest that teneligliptin prevents concentric LV hypertrophy, fibrosis, and development of congestive heart failure in Dahl salt-sensitive rats. Teneligliptin may inhibit pressure-overload hypertrophic adaption and result in LV eccentric hypertrophy with reduced LV ejection fraction. [ABSTRACT FROM AUTHOR]- Published
- 2018
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6. Global and Regional Right Ventricular Function Assessed by Novel Three-Dimensional Speckle-Tracking Echocardiography
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Ishizu, Tomoko, Seo, Yoshihiro, Atsumi, Akiko, Tanaka, Yumiko Oishi, Yamamoto, Masayoshi, Machino-Ohtsuka, Tomoko, Horigome, Hitoshi, Aonuma, Kazutaka, and Kawakami, Yasushi
- Abstract
Accurate assessment of global and regional right ventricular (RV) systolic function is challenging. The aims of this study were to confirm the reliability and feasibility of a three-dimensional (3D) speckle-tracking echocardiography (STE) system, using comparison with cardiac magnetic resonance imaging (CMR), and to assess the contribution of regional RV function to global function.
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- 2017
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7. Myocardial dysfunction identified by three-dimensional speckle tracking echocardiography in type 2 diabetes patients relates to complications of microangiopathy.
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Enomoto, Mami, Ishizu, Tomoko, Seo, Yoshihiro, Kameda, Yuri, Suzuki, Hiroaki, Shimano, Hiroshi, Kawakami, Yasushi, and Aonuma, Kazutaka
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Background The clinical effect of diabetic microangiopathy on left ventricular (LV) function is still uncertain. The purpose of this study was to assess the relation between diabetic microvascular complications and comprehensive myocardial deformation measurements using three-dimensional (3D) speckle tracking echocardiography. Methods Seventy-seven asymptomatic patients with type 2 diabetes mellitus (DM) and 35 age-matched healthy control subjects underwent 3D echocardiography. Patients with coronary artery disease or LV ejection fraction <50% were excluded. Presence of proliferative retinopathy, microalbuminuria as nephropathy, and decreased coefficient of variation of R-R intervals (CVRR) <3% as cardiac autonomic neuropathy were defined as diabetic microvascular complications. Results LV ejection fraction, LV mass index, and global radial strain did not differ between control and DM patients. However, global longitudinal and circumferential strain and endocardial area change ratio were lower in patients with DM than in the controls (−12.0 ± 3.0% vs. −16.2 ± 1.9%, −27.7 ± 7.1% vs. 32.2 ± 5.7%, −37.6 ± 7.6% vs. 44.0 ± 6.2%, respectively, p < 0.001). In DM patients, longitudinal strain is related to CVRR ( R = 0.58, p < 0.001), retinopathy stage, and nephropathy stage. Conclusions Diabetic microangiopathy and its accumulated effects significantly related to subclinical LV dysfunction are characterized by impaired longitudinal shortening. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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8. KLF15 Enables Rapid Switching between Lipogenesis and Gluconeogenesis during Fasting
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Takeuchi, Yoshinori, Yahagi, Naoya, Aita, Yuichi, Murayama, Yuki, Sawada, Yoshikazu, Piao, Xiaoying, Toya, Naoki, Oya, Yukari, Shikama, Akito, Takarada, Ayako, Masuda, Yukari, Nishi, Makiko, Kubota, Midori, Izumida, Yoshihiko, Yamamoto, Takashi, Sekiya, Motohiro, Matsuzaka, Takashi, Nakagawa, Yoshimi, Urayama, Osamu, Kawakami, Yasushi, Iizuka, Yoko, Gotoda, Takanari, Itaka, Keiji, Kataoka, Kazunori, Nagai, Ryozo, Kadowaki, Takashi, Yamada, Nobuhiro, Lu, Yuan, Jain, Mukesh K., and Shimano, Hitoshi
- Abstract
Hepatic lipogenesis is nutritionally regulated (i.e., downregulated during fasting and upregulated during the postprandial state) as an adaptation to the nutritional environment. While alterations in the expression level of the transcription factor SREBP-1c are known to be critical for nutritionally regulated lipogenesis, upstream mechanisms governing Srebf1expression remain unclear. Here, we show that the fasting-induced transcription factor KLF15, a key regulator of gluconeogenesis, forms a complex with LXR/RXR, specifically on the Srebf1promoter. This complex recruits the corepressor RIP140 instead of the coactivator SRC1, resulting in reduced Srebf1and thus downstream lipogenic enzyme expression during the early and euglycemic period of fasting prior to hypoglycemia and PKA activation. Through this mechanism, KLF15 overexpression specifically ameliorates hypertriglyceridemia without affecting LXR-mediated cholesterol metabolism. These findings reveal a key molecular link between glucose and lipid metabolism and have therapeutic implications for the treatment of hyperlipidemia.
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- 2016
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9. Clinical Implications of Intrarenal Hemodynamic Evaluation by Doppler Ultrasonography in Heart Failure
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Iida, Noriko, Seo, Yoshihiro, Sai, Seika, Machino-Ohtsuka, Tomoko, Yamamoto, Masayoshi, Ishizu, Tomoko, Kawakami, Yasushi, and Aonuma, Kazutaka
- Abstract
This study clarified the characteristics of intrarenal Doppler ultrasonography (IRD) profiles and their prognostic implications in heart failure (HF).
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- 2016
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10. Long-term exercise stimulates adenosine monophosphate–activated protein kinase activity and subunit expression in rat visceral adipose tissue and liver.
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Takekoshi, Kazuhiro, Fukuhara, Michiko, Quin, Zeng, Nissato, Sumiko, Isobe, Kazumasa, Kawakami, Yasushi, and Ohmori, Hajime
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ADIPOSE tissues ,SERINE ,ADENOSINE monophosphate ,PROTEIN kinases ,ADENOSINE triphosphate ,ACETYLCOENZYME A ,METABOLIC disorders - Abstract
Abstract: Adenosine monophosphate–activated protein kinase (AMPK) is activated in response to adenosine triphosphate depletion caused by the metabolic and nutritional state. Mammalian AMPK is a heterotrimeric enzyme composed of a catalytic α subunit and 2 regulatory subunits (β and γ). Although much attention has been focused on exercise-induced AMPK activation in skeletal muscle, little information is available on the role of AMPK in adipose tissue and liver. Acetyl-coenzyme A carboxylase (ACC) is a well-known downstream target of AMPK. The ACC contains serine residues that are phosphorylated by AMPK. The present study was undertaken to determine whether long-term exercise of medium intensity (60% of V˙o
2 max for 12 weeks) may influence AMPK enzyme activity, gene/protein expression, and subsequent ACC phosphorylation in rat adipose tissue (visceral and subcutaneous) and liver. We initially demonstrated that long-term exercise induced a significant increase in phosphorylation of Thr172 in the AMPK α1 subunit and of Ser79 in ACC in visceral adipose tissue rather than subcutaneous tissue. We also demonstrated that the AMPK α1 -,α2 -subunit messenger RNA (mRNA) level as well as the corresponding protein levels were increased in response to long-term exercise, whereas the other subunits were not altered significantly. In contrast to that of visceral adipose tissue, long-term exercise did not induce any significant effect on any of the AMPK subunit mRNA levels or α1 -,α2 -subunit protein levels in subcutaneous adipose tissue. In addition to adipose tissue, we demonstrated that long-term exercise induced an increase in both AMPK/ACC phosphorylation and α1 -,α2 -subunit mRNA/protein expression in the liver. Although the precise physiologic relevance of AMPK activation in these tissues remains unknown, it is possible that it might play an important role in long-term exercise-induced adaptation mechanisms and may lead to an improvement in certain metabolic abnormalities in metabolic diseases. [Copyright &y& Elsevier]- Published
- 2006
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11. Transmural Compensation of Myocardial Deformation to Preserve Left Ventricular Ejection Performance in Chronic Aortic Regurgitation
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Iida, Noriko, Seo, Yoshihiro, Ishizu, Tomoko, Nakajima, Hideki, Atsumi, Akiko, Yamamoto, Masayoshi, Machino-Ohtsuka, Tomoko, Kawamura, Ryo, Enomoto, Mami, Kawakami, Yasushi, and Aonuma, Kazutaka
- Abstract
In patients with chronic aortic regurgitation (AR), systolic wall stress and volume overload affects left ventricular (LV) systolic function and remodeling. The aim of this study was to assess transmural rearrangements of myocardial deformation to preserve LV ejection performances using speckle-tracking echocardiography in patients with chronic AR.
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- 2012
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12. Novel Germline Mutations in the SDHB and SDHDGenes in Japanese Pheochromocytomas
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Isobe, Kazumasa, Minowada, Shigeru, Tatsuno, Ichiro, Suzukawa, Kazumi, Nissato, Sumiko, Nanmoku, Toru, Hara, Hisato, Yashiro, Toru, Kawakami, Yasushi, and Takekoshi, Kazuhiro
- Abstract
AbstractThe SDHA, SDHB, SDHC,and SDHDgenes code for subunits of succinate dehydrogenase (SDH), which forms part of the mitochondrial respiratory chain. Germline mutations in the genes encoding SDHB and SDHD have been reported in familial paragangliomas/pheochromocytomas and in apparently sporadic pheochromocytomas. SDHBand SDHDmutations are widely distributed along the genes with no apparent hot spots. SDHBmutations are often detected in malignant and extra-adrenal pheochromocytomas. SDHDmutations are also detected frequently in head and neck paragangliomas. We sequenced the entire coding regions of the SDHBand SDHDgenes in 17 pheochromocytomas. Weidentified novel heterozygous G to A point mutations at the first base of intron 3 of the SDHBgene in a malignant extra-adrenal abdominal pheochromocytoma patient, and at the first base of codon 111 of the SDHDgene in an adrenal pheochromocytoma patient. Further, we confirmed the SDHDmutation by DHPLC. The prevalence of SDHB and SDHDmutations in pheochromocytomas we examined was 12 (2/17). Thus, we identified two novel SDH mutations in Japanese pheochromocytomas. Further studies will investigate the oncogenic potential of these mutations.Copyright © 2007 S. Karger AG, Basel
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- 2007
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13. Peptidergic Regulation of Pheochromocytoma
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Takekoshi, Kazuhiro, Isobe, Kazumasa, Kawakami, Yasushi, Shibuya, Shunsuke, Nakai, Toshiaki, and Okuda, Yukichi
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Pheochromocytoma contains and may synthesize a large number of peptides such as opioids (Leu-, Met-enkephalin), VIP, gastrin, calcitonin gene related peptide (CGRP), somatostatin, and adrenocorticotrophic hormone (ACTH). Also, circulating level of these peptides may be elevated. Although the precise contribution of these peptides secretion to the clinical features are largely unknown, it can be suggested that specific endocrine system could be involved in ectopic hormone production by pheochromocytoma. Indeed, it has occasionally been reported that pheochromocytoma is associated with Cushing's syndrome resulting from excess ACTH production. As there are already many excellent reviews of this area, the discussion that follows will mainly focus on our data, including 1.Opioids, 2.Adrenomedullin (AM) and proadrenomedullin N-terminal 20 peptide (PAMP), 3.Natriuretic peptides (NPs), 4.Leptin, 5.Endothelin 6. Angiotensin II receptor, 8. Chromogranin A and Catestatin.
- Published
- 2003
14. Tetraspanin CD9 Is a “Proteolipid,” and Its Interaction with α3Integrin in Microdomain Is Promoted by GM3 Ganglioside, Leading to Inhibition of Laminin-5-dependent Cell Motility*
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Kawakami, Yasushi, Kawakami, Kumiko, Steelant, Wim F.A., Ono, Masaya, Baek, Rena C., Handa, Kazuko, Withers, Donald A., and Hakomori, Senitiroh
- Abstract
GM3 ganglioside inhibits tetraspanin CD9-facilitated cell motility in various cell lines (Ono, M., Handa, K., Sonnino, S., Withers, D. A., Nagai, H., and Hakomori, S. (2001) Biochemistry40, 6414–6421). We now report the following: (i) CD9 has the novel feature of being soluble in chloroform/methanol, and classifiable as “proteolipid”; (ii) CD9 and α3integrin were concentrated together in the low-density glycolipid-enriched microdomain (GEM) of ldlD/CD9 cells, and the α3expression ratio (value for cells grown under +Gal condition divided by the value for cells grown under −Gal condition) in GEM of ldlD/CD9 cells was higher than that in control ldlD/moc cells, suggesting that CD9 recruits α3in GEM under +Gal condition, whereby GM3 is present. (iii) Chemical levels of α3and CD9 in the total extract or membrane fractions from cells grown under +Gal versus−Gal condition were nearly identical, whereas α3expressed at the cell surface, probed by antibody binding in flow cytometry, was higher under −Gal than +Gal condition. These results suggest that GM3 synthesized under +Gal condition promotes interaction of α3with CD9, which restricts α3binding to its antibody. A concept of the α3/CD9 interaction promoted by GM3 was further supported by (i) co-immunoprecipitation of CD9 and α3under +Gal but not −Gal condition, (ii) enhanced co-immunoprecipitation of CD9 and α3when GM3 was added exogenously to cells under −Gal condition, and (iii) the co-localization images of CD9 with α3and of GM3 with CD9 in fluorescence laser scanning confocal microscopy. Based on the promotion of α3/CD9 interaction by GM3 and the status of laminin-5 as a true ligand for α3, the laminin-5/α3-dependent motility of ldlD/CD9 cells was found to be greatly enhanced under −Gal condition, but strongly inhibited under +Gal condition. Such a motility difference under +Gal versus−Gal condition was not observed for ldlD/moc cells. The inhibitory effect observed in ldlD/CD9 cells under +Gal condition was reversed upon addition of anti-α3antibody and is therefore based on interaction between α3, CD9, and GM3 in GEM.
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- 2002
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15. Angiotensin subtype-2 receptor (AT2) negatively regulates subtype-1 receptor (AT1) in signal transduction pathways in cultured porcine adrenal medullary chromaffin cells
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Ishii, Kiyoaki, Takekoshi, Kazuhiro, Shibuya, Shunsuke, Kawakami, Yasushi, Isobe, Kazumasa, and Nakai, Toshiaki
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Two distinct types of angiotensin II (AngII) receptors, AT1and AT2, have been cloned. We have shown previously that stimulation of AT2reduces intracellular cyclic guanosine monophosphate (cGMP) levels in cultured porcine chromaffin cells in which AT2is the predominantly expressed receptor. However, it has not been determined whether AT1or AT2affects signal transduction pathways involving mitogen-activated protein kinases (MAPKs) and signal transducers and activators of transcription (STATs) in chromaffin cells. Also, it is unclear whether cGMP/protein kinase G (PKG) is involved in the regulation of MAPKs and STATs in these cells.
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- 2001
16. Insulin Up-regulates Tumor Necrosis Factor-α Production in Macrophages through an Extracellular-regulated Kinase-dependent Pathway*
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Iida, Kaoruko Tada, Shimano, Hitoshi, Kawakami, Yasushi, Sone, Hirohito, Toyoshima, Hideo, Suzuki, Seiji, Asano, Tomoichiro, Okuda, Yukichi, and Yamada, Nobuhiro
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Hyperinsulinemia has recently been reported as a risk factor for atherosclerotic diseases such as coronary heart disease; however, the effect of insulin on the development of atherosclerosis is not well understood. Here we have investigated the direct effect of insulin on macrophages, which are known to be important in the atherosclerotic process. We treated THP-1 macrophages with insulin (10−7m) and examined the gene expression using nucleic acid array systems. The results of array analysis showed that insulin stimulated gene expression of tumor necrosis factor-α (TNF-α) the most among all genes in the analysis. In addition, insulin administration to macrophages enhanced both mRNA expression and protein secretion of TNF-α in a dose-dependent manner. To determine the signaling pathway involved in this TNF-α response to insulin, we pretreated the cells with three distinct protein kinase inhibitors: wortmannin, PD98059, and SB203580. Only PD98059, which inhibits extracellular signal-regulated kinases, suppressed insulin-induced production of TNF-α mRNA and protein in THP-1 macrophages. These observations indicate that insulin stimulates TNF-α production in macrophages by regulating the expression of TNF-α mRNA and that the extracellular signal-regulated kinase signaling pathway may have a critical role in stimulating the production of TNF-α in response to insulin in macrophages.
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- 2001
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17. Neutralization of Vascular Endothelial Growth Factor Prevents Collagen-Induced Arthritis and Ameliorates Established Disease in Mice
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Sone, Hirohito, Kawakami, Yasushi, Sakauchi, Michihiro, Nakamura, Yasushi, Takahashi, Akimitsu, Shimano, Hitoshi, Okuda, Yukichi, Segawa, Toshiaki, Suzuki, Hideo, and Yamada, Nobuhiro
- Abstract
Vascular endothelial growth factor (VEGF) is implicated in the pathogenesis of inflammatory joint diseases, including rheumatoid arthritis (RA). To determine the importance of this cytokine in vivo, the effect of administering VEGF-neutralizing antibodies to mice with collagen-induced arthritis (CIA), which has many immunological and pathological similarities to human RA, has been investigated. Either saline, normal rabbit immunoglobulin or anti-human VEGF121 rabbit polyclonal antibody was administered to mice subcutaneously either before the onset of arthritis or after the establishment of clinical disease. Anti-VEGF antibody administered prior to disease onset significantly delayed the development of arthritis and decreased clinical score and paw thickness as well as histological severity. On the other hand, the frequency of occurrence of disease compared to either the control group administered saline or normal rabbit immunoglobulin was not altered. Anti-VEGF antibody also significantly ameliorated clinical and histological parameters even when administered after disease onset. These results indicate a possible therapeutical potential for anti-VEGF treatment in human arthritis.
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- 2001
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18. Orexins Suppress Catecholamine Synthesis and Secretion in Cultured PC12 Cells
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Nanmoku, Toru, Isobe, Kazumasa, Sakurai, Takeshi, Yamanaka, Akihiro, Takekoshi, Kazuhiro, Kawakami, Yasushi, Ishii, Kiyoaki, Goto, Katsutoshi, and Nakai, Toshiaki
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New orexigenic peptides called orexin-A and -B have recently been described in neurons of the lateral hypothalamus and perifornical area. No orexins have been found in adipose tissues or visceral organs, including the adrenal gland. However, expression of the orexin-receptor 2 (OX2R) in the rat adrenal gland has been reported. To test the effects of orexins on peripheral organs, we investigated their effects on catecholamine synthesis and secretion in the rat pheochromocytoma cell line PC12. Orexin-A and -B (100 nM) significantly reduced basal and PACAP-induced tyrosine hydroxylase (TH) (the rate-limiting enzyme in the biosynthesis of catecholamines) mRNA levels. Orexin-A and -B (100 nM) also significantly inhibited the PACAP-induced increase in the cAMP level, suggesting that the suppressive effect on TH mRNA is mediated, at least in part, by the cAMP/protein kinase A pathway. Furthermore, orexin-A and -B (100 nM) significantly suppressed basal and PACAP-induced dopamine secretion from PC12 cells. Next, we examined whether orexin receptors (OX1R, OX2R) were present in the rat adrenal gland and PC12 cells. In the adrenal glands, OX2R was as strongly expressed as in the hypothalamus, but OX1R was not detected. On the other hand, neither OX1R nor OX2R was expressed in PC12 cells. However, binding assays showed equal binding of orexin-A and -B to PC12 cells, suggesting the existence in these cells of some receptors for orexins. These results indicate that orexins suppress catecholamine release and synthesis, and that the inhibitory effect is mediated by the cAMP/protein kinase A pathway.
- Published
- 2000
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19. κ‐Opioid inhibits catecholamine biosynthesis in PC12 rat pheochromocytoma cell
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Takekoshi, Kazuhiro, Ishii, Kiyoaki, Kawakami, Yasushi, Isobe, Kazumasa, and Nakai, Toshiaki
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It was reported that nicotine‐induced dopamine release in the rat pheochromocytoma cell line, PC12 cells, was inhibited by κ‐opioid. However, it is not known whether inhibition of catecholamine biosynthesis is involved in the inhibitory mechanisms of κ‐opioids in PC12 cells. U‐69593 (a κ‐opioid agonist: ≥100 nM) significantly inhibited the nicotine‐induced increase of tyrosine hydroxylase (TH, a rate‐limiting enzyme in biosynthesis of catecholamine) enzyme activity and TH mRNA levels. These inhibitory effects were completely reversed by naloxone and nor‐binaltorphimine dihydrochloride (nor‐BNI), a specific κ‐antagonist, whereas pertussis toxin (PTX) only partially reversed this inhibitory effect. Also, U‐69593 (≥100 nM) significantly inhibited the nicotine‐induced increase of cAMP production. This inhibitory effect was completely reversed by naloxone and nor‐BNI, whilst only partially reversed by PTX. Moreover, U‐69593 (≥100 nM) significantly inhibited the nicotine‐induced increase of both the TH protein level and intracellular catecholamine levels. These results indicate that the anti‐cholinergic actions of κ‐opioid can be explained partially by its inhibition of both TH enzyme activity and TH synthesis, through suppression of the cAMP/protein kinase A pathway. It would also appear that the PTX‐sensitive G‐protein mediates the inhibitory effect of this pathway, at least in part.
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- 2000
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20. Angiotensin-II Subtype 2 Receptor Agonist (CGP-42112) Inhibits Catecholamine Biosynthesis in Cultured Porcine Adrenal Medullary Chromaffin Cells
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Takekoshi, Kazuhiro, Ishii, Kiyoaki, Isobe, Kazumasa, Nanmoku, Toru, Kawakami, Yasushi, and Nakai, Toshiaki
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Angiotensin II subtype 2 receptor (AT2-R) is abundantly expressed in adrenal medullary chromaffin cells. However, the physiological roles of AT2-R in chromaffin cells remain to be clarified. Therefore, we investigated the effects of CGP42112 (AT2-R agonist) on catecholamine biosynthesis in cultured porcine adrenal medullary cells. We initially confirmed AT2-R was predominantly expressed in porcine adrenal medullary cells by [125I]-Ang II binding studies. CGP42112 (≧1 nM) significantly inhibited cGMP production from the basal value. Tyrosine hydroxylase (TH) is a rate-limiting enzyme in the biosynthesis of catecholamine, and its activity is regulated by both TH-enzyme activity and TH-synthesis. CGP42112 (≧1 nM) significantly inhibited TH-enzyme activity from the basal value. These inhibitory effects of CGP42112 on TH-enzyme activity and-cGMP production were abolished by PD123319 (AT2-R antagonist) while CV-11974 (AT1-R antagonist) was ineffective. We also tested whether decrease of cGMP is involved in the inhibitory effect of CGP42112 on TH-enzyme activity. Pretreatment of 8-Br-cGMP (membrane-permeable cGMP analogue) prevented the inhibitory effect of CGP 42112 on TH-enzyme activity. Similar to that of TH-enzyme activity, CGP42112 (≧1 nM) significantly reduced TH-mRNA and TH-protein level from the basal value, and these inhibitory effects were abolished by PD123319 but not CV-11974. These findings demonstrate that CGP 42112 reduces both TH-enzyme activity and TH-synthesis and that these inhibitory effects could be mediated by decrease of cGMP production.
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- 2000
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21. EFFECT OF A TOPICALLY APPLIED NEUTRALIZING ANTIBODY AGAINST VASCULAR ENDOTHELIAL GROWTH FACTOR ON CORNEAL ALLOGRAFT REJECTION OF RAT1
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Yatoh, Shigeru, Kawakami, Yasushi, Imai, Masayuki, Kozawa, Tadahiko, Segawa, Toshiaki, Suzuki, Hideo, Yamashita, Kamejiro, and Okuda, Yukichi
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Studies in corneal transplant rejection remain important because acute immunologic rejection continues to be the leading cause of human corneal transplant failure. As the permeability of vessels and the neovascularization induce cells infiltration into the graft, we considered the possibility that vascular endothelial growth factor (VEGF), a potent permeability-increasing factor and angiogenesis-mediating factor, could participate in the immune response.
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- 1998
22. Vascular Endothelial Growth Factor Is Induced by Long-Term High Glucose Concentration and Up-Regulated by Acute Glucose Deprivation in Cultured Bovine Retinal Pigmented Epithelial Cells
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Sone, Hirohito, Kawakami, Yasushi, Okuda, Yukichi, Kondo, Shinichi, Hanatani, Mitsuya, Suzuki, Hideo, and Yamashita, Kamejiro
- Abstract
Vascular endothelial growth factor (VEGF) is closely correlated to diabetic retinopathy. Its basal production in three types of cultured retinal cells (endothelial cells, pericytes and retinal pigment epithelial cells; RPE) was examined. RPE production of VEGF was markedly higher than the rest of the cells. VEGF production in RPE was significantly elevated by 10-day, but not by 1- or 3-day exposure to 16.5 mM glucose compared to a 5.5 mM glucose group. Transient deterioration of diabetic retinopathy is frequently observed during rapid correction of glycemic control. To determine whether VEGF is up-regulated following a sharp drop in the glucose concentration or not, we examined the changes in VEGF production in RPE before and after a sudden drop in the glucose concentration. VEGF production was significantly increased by a glucose concentration decrease from 5.5 to 0.5 mM, but not by a decrease from 33 or 16.5 to 5.5 mM. These findings suggest that up-regulation of VEGF may contribute to the development of diabetic retinopathy and its worsening by hypoglycemia.
- Published
- 1996
- Full Text
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23. Proton‐donative antioxidant activity of fucoxanthin with 1,1‐Diphenyl‐2‐Picrylhydrazyl (DPPH)
- Author
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Nomura, Takaharu, Kikuchi, Masako, Kubodera, Akiko, and Kawakami, Yasushi
- Abstract
Reactions between a carotenoid, fucoxanthin and 1,1‐diphenyl‐2‐picrylhydrazyl were investigated both under anoxic and aerobic conditions. Fucoxanthin equimolarly reacted with 1,1‐diphenyl‐2‐picrylhydrazyl under anoxic conditions. Under aerobic conditions, only a part of fucoxanthin consumed 1,1‐diphenyl‐2‐picrylhydrazyl and the degree of reaction fluctuated with repeated trials. β‐Carotene or other carotenoids, β‐cryptoxanthin, zeaxanthin, licopen and lutein, were also examined in the reaction with 1,1‐diphenyl‐2‐picrylhydrazyl under anoxic conditions. All these compounds scarcely reacted with 1,1‐diphenyl‐2‐picrylhydrazyl.
- Published
- 1997
- Full Text
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24. Benzo(a)pyrene in the sediment of Osaka Bay and Keihin Canal and its estimated sources
- Author
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Kawakami, Yasushi and Nishimura, Hajime
- Abstract
Benzo(a)pyrene (BP) in the sediment of Osaka Bay were determined. High concentration was found at two stations near the mouth of Shin-Yodo and off Kobe respectively (0.98Μg g
−1 dry mud basis, 1.1Μg g−1 ). The concentration decreases regularly from the mouth of the river further into the bay. The other supplemental determination was carried on the sediment and the seawater of Keihin Canal. Notable BP concentration of 89Μg g−1 was observed in the sediment beneath the effluent outlet of a gasworks. The BP in the sediment near the ironworks was also considerable, while the BP was relatively less in the sediment beneath the effluent outlet of refineries. These data suggest that coke plants working in gasworks or ironworks may be the larger sources of BP than refineries. The results of Osaka Bay coincide with this hypothesis.- Published
- 1976
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25. Degradation of lubricating oils by marine bacteria observed by quantitative mass spectrometry
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Kawakami, Yasushi and Nishimura, Hajime
- Abstract
Bacterial degradation of the hydrocarbons of lubricating oils was investigated by mass spectrometric analysis which gives both total amount and the composition of hydrocarbon types of residual oil. An unused lubricating oil, which mainly consisted of hydrocarbon types with only a small percentage ofn-alkanes, was degraded by marineBacillussp. andPseudomonassp. with 55 % and 25 % decreases in 10 days, respectively. Susceptibility of respective hydrocarbon types to biodegradation was in the following order: alkanes > non-condensed cycloalkanes, mono-aromatics > condensed cycloalkanes. A used lubricating oil of different brand showed a larger decrease than the unused oil. Both species of bacteria degraded large portions of alkane fraction of Arabian light crude oil.
- Published
- 1981
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26. Cloning and characterization of extradiol aromatic ring-cleavage dioxygenases of Pseudomonas aeruginosaJI104
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Kitayama, Atsushi, Achioku, Tomohisa, Yanagawa, Takahiro, Kanou, Kenjiro, Kikuchi, Masako, Ueda, Hiroshi, Suzuki, Eiji, Nishimura, Hajime, Nagamune, Teruyuki, and Kawakami, Yasushi
- Abstract
We have cloned multiple extradiol aromatic ring-cleavage dioxygenase (EDO) genes from a gene library of Pseudomonas aeruginosaJI104, which is a benzene degrader isolated from soil near a gasworks. Southern hybridization analysis revealed that P. aeruginosaJI104 possessed three homologous catechol 2,3-dioxygenase (C23O) genes. Nucleotide sequences of the cloned C23O genes, xylEJI104-1,2,3were almost identical to that of the archetypal C23O gene (xylETOL), which is carried on the TOL plasmid, pWW0. We also cloned another EDO gene, bphCJI104, the product of which showed less activity for catechol than did XylEJI104, but higher activity for 2,3-dihydroxy biphenyl. The nucleotide sequence of bphCJI104was identical to that of bphCKF707(2,3-dihydroxybiphenyl dioxygenase gene of Pseudomonas pseudoalcaligenesKF707). The substrate specificities of the four EDOs of P. aeruginosaJI104 were markedly different from each other. Although XylEJI104-1and XylETOLwere 94% homologous, the specificities of the gene products for 4-chlorocatechol were extremely different. Results of a study of the chimeric enzymes composed of XylEJI104-1and XylETOLN- and C-terminal regions showed that the difference in the specificity for 4-chlorocatechol was dependent on the C-terminal amino acid sequences. All of the isofunctional homologous EDOs in P. aeruginosaJI104 seem to have been derived from a common ancestor and evolved into the present forms in which each EDO is involved in a different degradation pathway and they all coexist in one strain.
- Published
- 1996
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27. Secretion of genetically-engineered dihydrofolate reductase from Escherichia coli using an E. coli α-hemolysin membrane translocation system
- Author
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Nakano, Hideo, Kawakami, Yasushi, and Nishimura, Hajime
- Abstract
Summary Secretion of fusion proteins composed of cytoplasmic protein dihydrofolate reductase (DHFR) and the Escherichia coli α-haemolysin (HlyA) C-terminal sequence was examined through the haemolysin secretion machinery of E. coli. DHFR of various lengths was combined with the HlyA C-terminal region, and both secretion and DHFR activity of the fusions were measured. The secretion was found to be inversely correlated with the intracellular DHFR activity. Moreover, when one amino acid (Ile155) in a β-sheet of the DHFR C-terminal region was replaced with Lys, the enzymatically active DHFR fusion protein was secreted into the medium. We discuss the possibility of a relationship between folding and secretion of HlyA-fused protein in the HlyA secretion system.
- Published
- 1992
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28. Type II Alveolar Epithelial Cells in Lung Express Receptor for Advanced Glycation End Products (RAGE) Gene
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Katsuoka, Fumiki, Kawakami, Yasushi, Arai, Takeo, Imuta, Hiroyuki, Fujiwara, Masachika, Kanma, Hiroshi, and Yamashita, Kamejiro
- Abstract
Messenger RNA of receptor for advanced glycation end products (RAGE) is abundantly expressed in the lung. However, cell types expressing RAGE mRNA in the lung have not been identified. In order to elucidate the function of RAGE in pulmonary tissue, we have identified a cell type expressing RAGE mRNA byin situhybridization and compared its expression level of RAGE mRNA by RNA blot analysis of isolated cells.In situhybridization revealed that RAGE mRNA was intensely and specifically visualized in alveolar epithelial type II (AT-II) cells, and weakly in alveolar macrophages. The expression of RAGE mRNA in the primary culture of AT-II cells was at a high level, but that in alveolar macrophages isolated from alveolar lavage was under the level of detection by RNA blot analysis. These results showed that RAGE mRNA is specifically expressed in AT-II cells, and suggested that RAGE makes a substantial contribution to the function of AT-II cells in the lung.
- Published
- 1997
- Full Text
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29. Induction of experimental thyroiditis in mice by recombinant interferon γ administration
- Author
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Kawakami, Yasushi, Kuzuya, Nobuaki, Watanabe, Tsuyoshi, Uchiyama, Yasuo, and Yamashita, Kamejirou
- Abstract
Expression of major histocompatibility complex (MHC) class 2 molecules on the thyroid follicular cells in human autoimmune thyroid diseases has been reported, and is suggested to play a role in the initiation of the autoimmune responses. Interferon γ is known to induce MHC class 2 molecules on cultured thyrocytes. Therefore, we administered recombinant interferon γ to mice to induce MHC class 2 molecule expression in vivo, and investigated the thyroidal changes following MHC class 2 molecule expression. Recombinant interferon γ3 × 105U, was administered daily, to mice. MHC class 2 molecules, studied by indirect immunohistochemistry, were expressed on the follicular cells on the 2nd to 4th day after the first interferon γ administration and continued thereafter. Serum T4and T3concentrations decreased and anti-thyroglobulin antibodies and anti-microsomal antibodies were detected. Lymphocyte infiltrations were observed in the thyroid glands obtained at 28 days, but they were mild. These results suggest that MHC class 2 molecule expression on thyroid follicular cells induces anti-thyroid antibodies and plays an important role in the initiation of autoimmune thyroiditis. However, the progression of the immune response to thyroiditis with lymphocyte infiltration may require some other factor. This new model of autoimmune thyroid disease in mice might be useful to elucidate the pathogenesis of human autoimmune thyroid diseases.
- Published
- 1990
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- View/download PDF
30. SY10-2 - Recent Echocardiographic Advance in Right Ventricular Functional Assessment.
- Author
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Ishizu, Tomoko, Seo, Yoshihiro, Yamamoto, Masayoshi, and Kawakami, Yasushi
- Published
- 2017
- Full Text
- View/download PDF
31. Noninvasive Localization of Accessory Pathways in Wolff–Parkinson–White Syndrome by Three-Dimensional Speckle Tracking Echocardiography
- Author
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Ishizu, Tomoko, Seo, Yoshihiro, Igarashi, Miyako, Sekiguchi, Yukio, Machino-Ohtsuka, Tomoko, Ogawa, Kojiro, Kuroki, Kenji, Yamamoto, Masahiro, Nogami, Akihiko, Kawakami, Yasushi, and Aonuma, Kazutaka
- Abstract
Supplemental Digital Content is available in the text.
- Published
- 2016
- Full Text
- View/download PDF
32. Variation in the Shape of Genital Appendages along a Transect through Sympatric and Allopatric Areas of Two Brachypterous Grasshoppers, Parapodisma setouchiensis and Parapodisma subastris (Orthoptera: Podisminae)
- Author
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Kawakami, Yasushi and Tatsuta, Haruki
- Abstract
Divergence in genital traits between closely related species is occasionally greater in sympatry than in allopatry, possibly because directional selection facilitates differentiation so as to prevent unfit hybridization. Here, we report for the first time that the shape of a functional genital structure, cercus, differs markedly between sympatrically and allopatrically occurring individuals in two brachypterous grasshopper species, Parapodisma setouchiensis Inoue 1979 and Parapodisma subastris Huang 1983 (Orthoptera: Podisminae). Although in areas of allopatry the cerci were straight in both species, in areas of sympatry the cerci of P. setouchiensis had an almost orthogonal bend. Furthermore, the angles of curvature of the cerci of P. setouchiensis varied continuously along a transect through sympatric and allopatric areas. We also observed copulation behavior in pairs and found that the apical part of the cerci was inserted into the space between the posterior edges of the seventh abdominal sternite and the seventh abdominal tergite of the female. We suggest that the orthogonally bent cerci allows the male to obtain a firm grip on the female's abdomen and propose that the conspicuous variation in the cerci of P. setouchiensis contributes to the strength of reinforcement of a premating isolation system.
- Published
- 2010
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33. ChemInform Abstract: The Conformational Analysis of Organic Molecules by Theoretical Calculations.
- Author
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Kawakami, Jun, Kawakami, Yasushi, Miyamoto, Ryo, Nakamura, Kazuo, Kojima, Hisako, Tamai, Yoichi, and Ito, Shoei
- Abstract
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
- Published
- 2002
- Full Text
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34. Letter: Reply from Odawara and Yamashita
- Author
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Odawara, Masato, Kawakami, Yasushi, and Yamashita, Kamejiro
- Published
- 1997
- Full Text
- View/download PDF
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