Biomedical subjects

Junichi Hayashi

Publications and source records attributed to Junichi Hayashi.

10 recordsLinked to original sources

PubMed2006

Nitric oxide pathway activation and impaired red blood cell deformability with hypercholesterolemia.

The pathophysiological effects of the activation or inhibition of the nitric oxide (NO)-mediated pathway on the deformability of red blood cells (RBC) were evaluated in the presence of hypercholesterolemia induced in rabbits fed a cholesterol-rich diet. RBC deformability was assessed using a microchannel array flow analyzer system. The maximum passage time (MPT) by flowing a suspension of RBC through the microchannels was used as an index of RBC deformability. During cholesterol feeding for 12 weeks, MPT gradually increased with no significant elevation in the serum asymmetric dimethylarginine (ADMA) and arginine/ADMA ratio. The reduction in RBC deformability associated with hypercholesterolemia was significantly improved during incubation with each of three different NO pathway activators: a NO donor, 8-bromo-cyclic GMP, and arginine; however, no additional reduction was observed with ADMA administration. The inhibition of NO synthase due to ADMA caused a significant reduction in the deformability of normal RBC, which was reversed with NO pathway activation. These results suggest that impaired RBC deformability may be associated with a dysfunction in the NO pathway that is partially dependent upon the accumulation of ADMA in RBC, and exogenous NO pathway activators may improve the microcirculation by restoring RBC deformability in the presence of hypercholesterolemia.

Animals↗

PubMed2005

Long-term inhibition of intimal hyperplasia using vascular photodynamic therapy in balloon-injured carotid arteries.

Flexible treatments for intimal hyperplasia after angioplasty are still needed. The aim of this study was to demonstrate the long-term effects of vascular photodynamic therapy with talaporfin sodium on intimal hyperplasia following interventional injury. Intimal hyperplasia was induced by balloon distension injury to the carotid artery in 31 rabbits. Talaporfin, 5.0 mg/kg, was delivered systemically immediately after balloon injury. The injury site was irradiated with a diode laser light of wavelength 664 nm using a fluence of 50 J/cm2 after 30 min. At day 3 and weeks 3, 6, 9, 15, and 25 after photodynamic therapy, the treated artery of each rabbit was excised and examined immunohistochemically. Thirty minutes after talaporfin administration, drug fluorescence was found only in the balloon-injured carotid artery wall. At 3 days, no smooth muscle cells were seen in the media of the photodynamic therapy-treated arterial segments. Intimal hyperplasia developed progressively in the balloon-injured and untreated segments; however, in the segments treated with photodynamic therapy, intimal hyperplasia was markedly suppressed until 25 weeks and the media was repopulated by smooth muscle cells without macrophages. Vascular photodynamic therapy with talaporfin may be used to inhibit restenosis after vascular intervention.

Actins↗

PubMed2005

Unsuccessful internal defibrillation in Brugada syndrome: focus on refractoriness and ventricular fibrillation cycle length.

INTRODUCTION: In patients with Brugada syndrome, implantable cardioverter defibrillator (ICD) is the only reliable treatment to prevent sudden death though, in some cases, internal defibrillation may be unsuccessful. The aim of this study was to examine the determinants of defibrillation failure, with a focus on electrophysiologic characteristics. METHODS: The study included 51 patients treated with ICD: 22 with Brugada syndrome and 29 with structural heart disease (SHD). The prevalence of defibrillation energy requirement precluding the programming of a 10-J safety margin, the mean right ventricular effective refractory period (ERP), and mean induced ventricular fibrillation cycle length (VFCL) from the stored ICD electrograms, were compared between the two patient groups. RESULTS: High defibrillation requirements were observed in 18% of patients with Brugada syndrome versus 0% of patients with SHD. However, the patients with SHD had larger heart size than those with Brugada syndrome. Mean VFCL and mean ERP were both significantly shorter in patients with Brugada syndrome than in patients with SHD, and ERP and VFCL were significantly correlated. CONCLUSION: Patients with Brugada syndrome have a high prevalence of high defibrillation energy requirement, and short ventricular ERP and VFCL.

Bundle-Branch Block↗

PubMed2005

Pericardial abscess detected by Gallium-67 scintigraphy 40 years after cardiac surgery.

A 45-year-old female who had cardiac surgery 40 years earlier was transferred to our hospital because of refractory fever. Echocardiography showed an intrapericardial mass. Gallium-67 (67Ga) scintigraphy revealed abnormal accumulation at the same site of the intrapericardial mass and thoracoscopy revealed that the mass was a pericardial abscess (PA). After surgical resection, drainage and antibiotic therapy, her fever subsided and the abnormal accumulation of 67Ga disappeared. This case showed a very rare clinical course of PA and the importance of 67Ga scintigraphy for its diagnosis.

Abscess↗

PubMed2005

A population-based study of arterial stiffness index in relation to cardiovascular risk factors.

We investigated the relation of arterial stiffness, considered an independent predictor of cardiovascular events, to cardiovascular risk factors in a population-based study of 1023 subjects. An Arterial Stiffness Index (ASI) was developed to evaluate arterial stiffness based on an analysis of the pulse wave amplitude pattern acquired from measurements of brachial blood pressure. In control subjects (n = 266) without any major risk factors, the ASI was 46 +/- 11, and increased with age (r = 0.346). The ASI was significantly higher in women ranging from 50 to 54 years of age than in age-matched men. The ASI rose in correlation with the number of risk factors. Subjects with two risk factors showed a significantly higher ASI than those without any risk factors (54 +/- 26 vs. 46 +/- 11). The ASI was significantly increased in diabetic subjects with hypertension in comparison to those without hypertension. Furthermore, hyperlipidemic subjects with hypertension showed significantly higher values than those without hypertension. ASI could be a useful predictor of cardiovascular events in hypertensive subjects with multiple risk factors.

Adult↗

PubMed2003

Treatment of a spontaneous intracranial dissecting aneurysm with stent-assisted coil embolization.

Arterial dissection is now recognized as an important cause of stroke. Most reported dissections involve the extracranial portion of the internal carotid artery (ICA) and vertebral arteries. Spontaneous dissecting aneurysms of the intracranial ICA are uncommon. Endovascular treatment for cerebral aneurysms has become widespread; however, the dissecting aneurysm is still difficult to treat if the parent artery has to be preserved. More recently, stenting has been advocated for use with endosaccular coiling, with the coils held in place by the stent. We herein report a spontaneous intracranial ICA dissecting aneurysm in a 51-year-old woman who was treated using a new technique of combined stent and coils.

Aortic Dissection↗

PubMed2002

Concomitant expression of heparin-binding epidermal growth factor-like growth factor mRNA and basic fibroblast growth factor mRNA in myocardial infarction in rats.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is mitogenic and chemotactic for many cell types. HB-EGF is induced in pathological states which require cell mitogenesis and proliferation, including angiogenesis, and has been reported to interact functionally with basic fibroblast growth factor (bFGF). To test our hypothesis that HB-EGF mRNA expression is increased in myocardial infarction, we used Northern hybridization in rats to investigate the expression of HB-EGF and EGF receptor mRNAs expression in the infarct zone compared to the expression of bFGF and FGF receptor mRNAs. We also performed in situ hybridization to identify the cells responsible for HB-EGF mRNA production. HB-EGF mRNA rapidly increased after ligation (mean +/- SE, 5.6+/-0.23-fold increase at 6 hours compared to the preligation heart levels) and reached a maximum level (9.1+/-0.42-fold increase) around 12 hours. HB-EGF mRNA then gradually decreased on day 1 (5.8+/-1.0-fold increase), day 2 (3.2+/-0.94-fold increase) and day 3 (1.9+/-0.33-fold increase) after ligation. Parallel changes in bFGF mRNA expression were observed (6, 12 hours, days 1, 2 and 3; 3.6+/-0.42-, 5.3+/-0.12-, 2.3+/-0.12-, 1.7+/-0.03- and 0.95+/-0.03-fold increase, respectively). EGF receptor (ErbB-1) mRNA was gradually increased on day 2 (2.4+/-0.53-fold increase), day 7(4.0+/-0.61-fold increase) and day 14 (7.0+/-0.61-fold increase). Similarly, FGF receptor (FGF receptor-1) mRNA was gradually increased (days 2,7 and 14; 1.3+/-0.13-, 1.5+/-0.17- and 2.3+/-0.15-fold increase, respectively). Reperfusion after a 2-hour ligation (too late to salvage myocytes) enhanced HB-EGF (12 hours, 16.8+/-1.8-fold increase) and bFGF (12 hours, 10.4+/-1.1-fold increase) mRNA expression. The cells responsible for the increased production of HB-EGF mRNA were shown by in situ hybridization to be surviving myocytes located in the infarct peripheral zone around infarct necrotizing tissue. In conclusion, our results demonstrated a rapid increase in HB-EGF mRNA expression concomitant with an increase in bFGF mRNA expression, suggesting that HB-EGF and bFGF might play some role in the course of pathological changes in the infarct in the early inflammatory phase. Reperfusion at times too late to salvage myocytes accelerated sequential changes in the expression of both HB-EGF and bFGF mRNAs.

Animals↗

PubMedDate not supplied

Spatially and temporally different expression of osteonectin and osteopontin in the infarct zone of experimentally induced myocardial infarction in rats.

Osteonectin and osteopontin, two secreted matricellular proteins, have a variety of functions that are exerted through interaction with matrix components. These proteins appear in response to tissue injury. To test our hypothesis that osteopontin and osteonectin are expressed with spatially and temporally different patterns in myocardial infarct tissue, we investigated osteonectin and osteopontin expression in experimentally induced myocardial infarction in rats, in comparison with Type I collagen expression. Northern blotting demonstrated that osteonectin mRNA did not markedly increase on Day 2 after the infarction, but it increased on Days 7 and 14 by 1.7+/-0.12- and 1.8+/-0.01-fold compared to that in preligation hearts. In contrast, osteopontin mRNA was increased on Day 1 (41.9+/-11.3-fold increase) and on Day 2 (58.3+/-7.6-fold increase), and then it declined on Days 7 and 14 (24.8+/-9.0- and 13.5+/-4.7-fold increase, respectively). In situ hybridization revealed that osteonectin mRNA signals were observed in fibroblasts, myofibroblasts and macrophages around infarct necrotic tissue on Days 7 and 14. Osteopontin mRNA signals were observed in macrophages in the infarct marginal zone on Day 2. Immunopositive staining for both osteonectin and osteopontin showed the same pattern as that obtained by in situ hybridization. The time course of osteonectin mRNA was almost parallel with that of Type I collagen mRNA, while that of osteopontin was not. These results demonstrated spatially and temporally different expression patterns of osteonectin and osteopontin in myocardial infarction and suggest that osteonectin appears to be involved in the pathological course in the late phase after infarction concomitantly with Type I collagen, while osteopontin may play a role in the early phase.

Animals↗

PubMedDate not supplied

Marked decrease of plasma VEGF after implantation of autologous bone marrow mononuclear cells in a patient with critical limb ischemia--a case report.

The authors performed autologous bone marrow mononuclear cells implantation (BMI) in a 79-year-old man with critical limb ischemia. After BMI, the resting pain of the ischemic leg improved gradually. They measured the plasma concentrations of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and serum hepatocyte growth factor (HGF) in the blood from bilateral femoral veins. Before BMI, the plasma VEGF and bFGF concentrations were much greater in the ischemic leg than in the other lower limb, but decreased to the same concentrations as those in the contralateral lower extremity after BMI. The large concentrations of the angiogenic factors VEGF and bFGF in plasma indicate the severity and extent of the leg ischemia. BMI resulted in lower levels of VEGF and bFGF, and this fall is the hallmark of the effectiveness of BMI in the treatment of peripheral artery disease.

Aged↗

PubMedDate not supplied

CT angiography with electrocardiographically gated reconstruction for visualizing pulsation of intracranial aneurysms: identification of aneurysmal protuberance presumably associated with wall thinning.

Electrocardiographically (ECG) gated multisection helical CT images were obtained in 23 patients with ruptured intracranial aneurysms. 4D-CTA (3D CT angiography plus phase data) images were generated by ECG-gated reconstruction. Four patients showed pulsation of an aneurysmal bleb. Clipping was performed in two of these patients, and the rupture site matched the pulsatile bleb seen in 4D-CTA.

Adult↗