Publications by authors named "Naokazu Hamada"

Article Synopsis
  • Ghrelin, a hormone mainly secreted by the stomach, influences blood pressure and vascular tone but its production in relation to blood pressure is not fully understood.
  • A study investigated the impact of different antihypertensive drugs on ghrelin levels in two rat strains: spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) over four weeks.
  • Results showed that while drugs reduced blood pressure and led to lower ghrelin levels in WKY rats, SHR rats did not exhibit significant changes in ghrelin production, suggesting a disrupted relationship between ghrelin and blood pressure in hypertensive conditions.
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Objective: Washout rate of iodine-123 metaiodobenzylguanidine (MIBG) myocardial scintigraphy is correlated with the degree of myocardial damage. The aim of this study is to ascertain whether there is any relationship between QRS complex duration at right ventricle (RV) pacing and the degree of myocardial damage assessed by I-123 MIBG myocardial scintigraphy in normally functioning left ventricle.

Methods: The study included 22 patients (10 men and 12 women, ranging in age from 48 to 89 years), with atrioventricular (AV) block (n = 15) and sick sinus syndrome (n = 7).

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Objectives: The exact role of pressure gradient across the prosthetic valve estimated from Doppler flow velocity remains controversial. This in-vivo study was designed to assess the actual discrepancy between Doppler and catheter measurements of the pressure gradients for small bileaflet prosthetic valves in the aortic position.

Methods: Bileaflet prosthetic valves (19 mm-ATS) were implanted into the aortic position in pigs, and pressure gradients across the valves were examined by volume loading under right heart bypass.

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We encountered a 72-year-old woman with a left atrial hemangioma arising in the appendage and growing like an extracardiac mass. Life-threatening cardiac tamponade, recurrent over a 5-year clinical course, was the only sign of this rare tumor. The extraatrial growth pattern of the tumor made it difficult to distinguish the cardiac origin from a paracardiac mass.

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To clarify whether inflammation is a cause or consequence of atrial fibrillation (AF), we measured high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-alpha) before and after pharmacological cardioversion in 15 patients with paroxysmal AF. Levels of hs-CRP, IL-6, and TNF-alpha after cardioversion were significantly higher than those in controls (P < 0.05).

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