Publications by authors named "Tamio Nakajima"

Contrast-induced nephropathy (CIN) is clinically important because of its poor prognosis. The incidence of CIN is higher in emergency than elective percutaneous coronary intervention (PCI) because there is no established method to prevent CIN. The aim of this study is to evaluate whether bolus administration of a concentrated solution of sodium bicarbonate can prevent CIN in patients undergoing emergency PCI.

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Background: Previous studies have reported that high-dose strong statin therapy reduces the incidence of contrast-induced nephropathy (CIN) in statin naïve patients; however, the efficacy of high-dose strong statins for preventing CIN in real-world clinical practice remains unclear. The aim of this study was to evaluate the efficacy of strong statin therapy in addition to fluid hydration for preventing CIN after cardiovascular catheterization.

Methods and results: This prospective, multicenter, randomized controlled trial included 420 patients with chronic kidney disease who underwent cardiovascular catheterization.

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Background: Evaluation of left ventricular (LV) diastolic function is essential for the management of heart failure. We verified whether LV diastolic function could be evaluated by measuring the fractional area change (FAC) using cine cardiovascular magnetic resonance (CMR).

Methods: We collected clinical data from 59 patients who underwent echocardiography and cine CMR.

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Aims: Ablation of right-sided accessory pathways (APs) is sometimes challenging because several anatomical features of the tricuspid annulus (TA) and surrounding structures differ from those of the mitral annulus. This study investigated the electrophysiological characteristics and efficacy of a non-contact mapping (NCM) system for catheter ablation of right-sided APs.

Methods And Results: We examined nine APs in six consecutive patients who underwent catheter ablation of right-sided APs with NCM.

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A 78-year-old man with a history of pulmonary tuberculosis was referred for preoperative evaluation of cardiac function. Echocardiography and cardiac cine magnetic resonance imaging (MRI) indicated apical hypertrophic cardiomyopathy (HCM), a thickened visceral pericardium, and a large pericardial effusion. Cardiac late gadolinium-enhanced MRI revealed pericardial inflammation or fibrosis.

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We present an alternative method for evaluating cardiac fat tissue-dual gradient-echo in-phase and opposed-phase magnetic resonance imaging (IPOP-MRI) with electrocardiographic (ECG) gating. Conventional IPOP-MRI can be used to evaluate small amounts of fat and is widely used for abdominal imaging, but cardiac motion artifacts make its use difficult for cardiac imaging. Using ECG gating prior to IPOP-MRI, we evaluated lipomatous metaplasia after myocardial infarction.

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Background: Contrast-enhanced cardiac magnetic resonance imaging (MRI) can depict papillary muscle (PM) necrosis or fibrosis by late enhancement (LE) of PM, but its clinical significance in old myocardial infarction (OMI) has been little understood.

Methods: Myocardial LE and PM-LE were detected with contrast imaging in 60 patients with OMI caused by a single culprit coronary artery lesion. Left ventricular (LV) morphology and function, mitral valve geometry, and severity of mitral regurgitation were also evaluated by cine imaging.

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Background: Renal dysfunction is commonly accompanied by a worsening of atherosclerosis; however, the underlying molecular mechanism is not fully understood. We examined the role played by soluble fms-like tyrosine kinase-1 (sFlt-1), an endogenous antagonist of the proatherogenic cytokine placental growth factor (PlGF), in the worsening of atherosclerosis in patients with renal dysfunction and in an animal model of renal failure.

Methods And Results: In this study, 329 patients who received cardiac catheterization and 76 patients who underwent renal biopsy were enrolled.

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Article Synopsis
  • - The study investigates the role of soluble Fms-like tyrosine kinase-1 (sFlt-1) in patients with acute myocardial infarction (MI), highlighting its potential as a biomarker for risk of acute heart failure.
  • - Plasma levels of sFlt-1 were found to be significantly higher in acute MI patients compared to controls and even higher in those who later developed severe heart failure needing mechanical support.
  • - The findings suggest that measuring sFlt-1 levels upon admission could help predict the risk of complications, providing valuable insights for managing patients after an MI event.
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Background: Placental growth factor (PlGF), a homolog of vascular endothelial growth factor, is reported to stimulate angiogenesis and arteriogenesis in pathological conditions. It was recently demonstrated that PlGF is rapidly produced in myocardial tissue during acute myocardial infarction (MI). However, the effects of exogenous PlGF administration on the healing process after MI are not fully understood.

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Aldosterone synthase (CYP11B2) and 11 beta-hydroxylase (CYP11B1) regulate aldosterone and cortisol production, respectively. The expression of these enzymes is promoted by calcium influx through Cav3.2, a T-type calcium channel.

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Aim: We previously found, using a mouse model, that activation of proinflammatory cytokines after acute myocardial infarction (AMI) augments neointimal hyperplasia of a remote artery. The present study assessed the progression of luminal narrowing of non-culprit coronary arteries (NCCA) in patients following AMI.

Methods: The study group comprised 21 AMI patients successfully treated with bare-metal stents and 16 stable angina (SA) patients treated with sirolimus-eluting stents.

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The aim of the present study is to clarify the roles of circulating ADAMTS13 and von Willebrand factor (VWF) in the formation of coronary artery thrombi in acute myocardial infarction (AMI). Twenty-six AMI patients, 37 age-matched healthy controls, and 20 young controls were studied. Plasma ADAMTS13 activity and levels of VWF antigen (VWF: Ag) and unusually large VWF multimer (UL-VWFM) were measured in the femoral vein (FV), aortic root (Ao), and coronary sinus (Cs) immediately before percutaneous coronary intervention (PCI) during the acute phase of AMI, as well as 6 months later.

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Background: Although sonothrombolysis has been studied for development of recanalization that is safer and more efficacious than the methods currently used, there have been no studies of the efficacy of sonothrombolysis for the platelet-rich thrombi that typically cause acute myocardial infarction (AMI). The effects of adding ultrasound (US) to pharmacological lysis of platelet-rich thrombi was examined in a rabbit model of femoral artery occlusion.

Methods And Results: In 35 rabbits, the right femoral artery was balloon-injured repeatedly at 4-week intervals to induce platelet-rich thrombi.

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Efonidipine can block both L- and T- type Ca2+ channels. In a previous in vitro study, we clarified that efonidipine dramatically suppresses aldosterone secretion from human adrenocortical tumor cells during angiotensin II (Ang II)- and K+-stimulation, whereas nifedipine, a dominant L-type Ca2+ channel antagonist, does not. This study was conducted to assess the in vivo effects of efonidipine and nilvadipine on the plasma aldosterone concentration.

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Background: Although multislice spiral computed tomography (MSCT) is a promising technique for non-invasive coronary angiography, its usefulness in patients with stent implantation remains unclear. The aim of the present study was to compare the usefulness of MSCT with that of invasive coronary angiography for evaluating coronary stent patency.

Methods And Results: Thirty-one patients were enrolled after coronary stent implantation.

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Objectives: Our aim was to investigate cardiac expression of placental growth factor (PlGF) and its clinical significance in patients with acute myocardial infarction (AMI).

Background: Placental growth factor is known to stimulate wound healing by activating mononuclear cells and inducing angiogenesis. The clinical significance of PlGF in AMI is not yet known.

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Targeting aldosterone synthesis and/or release represents a potentially useful approach to the prevention of cardiovascular disease. Aldosterone production is stimulated by angiotensin II (Ang II) or extracellular K+ and is mediated mainly by Ca2+ influx into adrenal glomerulosa cells through T-type calcium channels. We therefore examined the effects of efonidipine, a dual T-type/L-type Ca2+ channel blocker, on aldosterone secretion in the H295R human adrenocarcinoma cell line; 100 nmol/L Ang II and 10 mmol/L K+ respectively increased aldosterone secretion from H295R cells 12-fold and 9-fold over baseline.

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Bone tissue, with its dynamic microenvironment featuring osteoclastic bone resorption, angiogenesis and matrix degradation, appears to facilitate proliferation of tumor cells after the onset of bone metastasis. In this study, we examined metastatic lesions in the femora of BALB/c nu/nu mice two weeks after intracardiac injection with human breast carcinoma MDA-231 cells. Histopathological observations showed the metastatic lesions close to the chondro-osseous junction, and revealed MDA-231 cells loosely intermingled with different cell types such as osteoblasts, fibroblastic stromal cells, osteoclasts and endothelial cells.

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The effects of cryopreservation on periodontal regeneration of transplanted rat molars were investigated histologically and histochemically in rats. Bilateral first and second maxillary molars of 4-week-old Wistar rats were gently extracted and transplanted into the abdominal subcutaneous connective tissue immediately or after cryopreservation in liquid nitrogen overnight. Donor teeth were slowly frozen by a rate-controlling freezer (program freezer) using 5% dimethylsulfoxide (DMSO) and 6% hydroxyethyl starch (HES) as cryoprotectants.

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Osteoclast differentiation in the process of ectopic bone formation induced by recombinant human bone morphogenetic protein 2 (rhBMP-2) was examined to clarify the relationship between osteoclast development and rhBMP-2-induced bone formation. A combination of rhBMP-2 with a porous microsphere (PMS) and blood clot was implanted subcutaneously on the bilateral chest muscles of rats. Tartrate-resistant acid phosphatase (TRAPase) activity, cathepsin K (cath K), and calcitonin receptor (CTR), as markers of osteoclasts and their precursors, were examined using enzyme and immunohistochemical analysis up to 7 days after implantation.

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Parathyroid hormone-related peptide (PTHrP) induces pathological bone resorption in an endocrine manner, resulting in hypercalcemia of malignancy. However, the histopathological aspect of the action of PTHrP secreted by tumor cells on bone resorption has not well been documented. Therefore, we studied cell-cell interactions between bone cells, stromal cells, and PTHrP-secreting tumor cells (EC-GI-10) morphologically.

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Background: It is still unknown how jaw bone remodeling occurs at actual invasion sites of oral squamous cell carcinomas. Since there is no other human carcinomas which make a direct invasion of the bone, gingival carcinomas are valuable examples.

Methods: Twelve surgical specimens of gingival squamous cell carcinoma were examined histopathologically and immunohistochemically for remodeling of bone and its surrounding tissue.

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To determine the effects of a bisphosphonate on the quality of bone morphogenetic protein-(BMP-) induced bone, incadronate was administered to rats in which subcutaneous ectopic bones were induced by recombinant human BMP-2. Incadronate (1 microg/kg/day) was administered to rats carrying the BMP-induced bones three times per week, from the 3rd to 7th week after BMP implantation (incadronate group). Aliquots of phosphate-buffered saline were administered in the same protocol without incadronate to the control group.

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Background: To assess the effect of clinicopathologic factors on local tumor control and survival in patients with mandibular alveolar carcinoma.

Methods: Fifty patients with mandibular alveolar carcinoma treated surgically were included in this study. There were 3 patients with T1, 25 with T2, 5 with T3, and 17 with T4 disease.

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