Mass Transfer in Mesoporous Microparticles Studied by Confocal Fluorescence Recovery after Photobleaching.

The intraparticle diffusion of a fluorescent dye in single microparticles in an aqueous solution was analyzed using fluorescence recovery after photobleaching, with a confocal fluorescence microscope. The fluorescence depth profile of single microparticles, and the fluorescence recovery at the particle center, were measured; further, the intraparticle diffusion coefficient was determined through simulations of three-dimensional diffusion in the respective microparticles. The intraparticle diffusion of coumarin 102 in octadecylsilyl silica gel was limited by the surface diffusion.

Torsades de Pointes with QT prolongation related to donepezil use.

An 83-year-old female, who had a history of anterior myocardial infarction, was treated for Alzheimer's disease with donepezil. She suffered from repeated diarrhea and vomiting, and experienced syncope. She was admitted to our hospital and was diagnosed with acute colitis and syncope. On admission, her heart rate was 54 beats/min with regular rhythm. Laboratory data showed a low plasma potassium level. Electrocardiogram (ECG) showed poor R progression, ST elevation, negative T in precordial leads, and marked QT prolongation. Transthoracic echocardiogram showed the enlargement of the left atrium and aneurysmal area at the apex. Torsades de Pointes (TdP) with syncope and convulsion were confirmed on ECG monitoring twice after admission. We treated her with potassium chloride and started magnesium sulfate and lidocaine, and then added isoprenaline injection. After these treatments, her heart rate increased and we did not detect TdP again. With the aging population in Japan, prescriptions for donepezil are increasing. We have to be vigilant for syncope in patients taking donepezil, which is possibly related to QT prolongation and TdP.

Usefulness of transesophageal echocardiographic observation during chemotherapy for cardiac metastasis of non-Hodgkin lymphoma complicated with left ventricular diastolic collapse.

A 53-year-old man, who had been treated for penile origin diffuse large B cell type non-Hodgkin lymphoma (NHL), suffered from right femoral pain and dyspnea. Positron emission tomography (PET) revealed abnormal accumulation in his right femur and cardiac segments. Transthoracic echocardiography revealed massive localized pericardial effusion with the collapse of both ventricles and the mass-like echo in the left atrium. We performed emergent pericardiocentesis and diagnosed this case as a recurrence of NHL with cardiac metastasis. With the use of transesophageal echocardiography (TEE), we confirmed the mass-like echo around the inter-atrial septum, which directly invaded to the aortic ring and the right atrial wall. In order to evaluate the effect of chemotherapy, we performed TEE and observed the precise changes of intra-cardiac tumor size. With the use of TEE monitoring, we could select the appropriate chemotherapeutic regimen, and the tumor became smaller and finally diminished. The femoral accumulation detected by PET also disappeared. We experienced a case of cardiac metastasis of NHL complicated with left ventricular diastolic collapse due to the massive localized pericardial effusion. TEE is a useful tool to evaluate precisely the efficacy of chemotherapy for intra-cardiac tumors.

Mitral regurgitation resulting from the consecutive multiple perforations by infective endocarditis mimicking the isolated anterior mitral cleft.

A 60-year-old man, suffering from sustained cough and dyspnea on effort, was diagnosed as congestive heart failure. He did not yield the history of having fever or other inflammatory events. His physical examination disclosed a pan-systolic murmur at the apex. Transthoracic color Doppler echocardiography showed moderate to severe mitral regurgitation originated from the linear tear of the anterior mitral leaflet. The tear reached to the mid-portion of the leaflet just within the postero-medial commissure and the regurgitant flow convergence was not hemispheric, but box-like shaped, suggesting that the linear tear was the isolated mitral cleft. Transesophageal echocardiography showed the almost same findings and we found no other anomalies. Surgical treatment was selected to repair the mitral regurgitation. Under operation, we found three consecutive perforations located linearly in the anterior mitral leaflet. The mitral valve replaced with the prosthetic one. The pathological examination of the resected valve showed mucinous degeneration of the chordae tendineae and fibrinoid change without inflammatory cellular infiltration. These findings were compatible with the healed infective endocarditis. Here we experienced a curious case of mitral regurgitation, caused by consecutive three mitral perforations mimicking the isolated anterior mitral cleft.

Vitamin C restores the contractile response to dobutamine and improves myocardial efficiency in patients with heart failure after anterior myocardial infarction.

BACKGROUND: Excessive oxidative stress is considered one of the mechanisms of a decrease in contractile force without concomitant reduction in oxygen cost in failing myocardium. We hypothesized that the antioxidant vitamin C may help reverse hyporesponsiveness to beta-adrenergic stimulation and improve myocardial efficiency in patients with heart failure (HF) after myocardial infarction (MI). METHODS AND RESULTS: Nineteen patients with mild to moderate HF due to previous MI (mean left ventricular [LV] ejection fraction 39%) were instrumented with conductance and coronary sinus thermodilution catheters. Left ventricular contractility, expressed as E(es), the slope of end-systolic pressure-volume relationship, and mechanical efficiency, expressed as the ratio of LV stroke work (SW) to myocardial oxygen consumption (MVO2), were measured in response to the intravenous infusion of dobutamine (4 microg/kg per min) before (Dob) and during (Dob + Vit C) the infusion of vitamin C (2.0-g bolus injection and subsequent 50-mg/min infusion through the jugular vein) (vitamin C group, n = 10). The infusion of vitamin C augmented the E(es) response to dobutamine by 20% +/- 8% (Dob 2.1 +/- 0.3, Dob + Vit C 2.5 +/- 0.4 mm Hg/mL, P < .01) and the SW/MVO2 response by 21% +/- 5% (Dob 36% +/- 3%, Dob + Vit C 43% +/- 4%, P < .01). In the control group (n = 9), E(es) and SW/MVO2 were measured in response to dobutamine before (Dob) and during (Dob + vehicle) the infusion of saline. No difference in E(es) or SW/MVO2 was observed between Dob and Dob + vehicle (E(es): Dob 2.1 +/- 0.2, Dob + vehicle 2.1 +/- 0.2 mm Hg/mL per square meter, P = nonsignificant) (SW/MVO2: Dob 35% +/- 4%, Dob + vehicle 33% +/- 4%, P = nonsignificant). CONCLUSION: The administration of the antioxidant vitamin C enhances the contractile response to dobutamine and improves myocardial efficiency in patients with HF.

Inhibition of endogenous nitric oxide synthase augments contractile response to adenylyl cyclase stimulation without altering mechanical efficiency in patients with idiopathic dilated cardiomyopathy.

BACKGROUND: Increased nitric oxide (NO) in the failing heart attenuates the myocardial contractile response to beta-adrenergic receptor stimulation. However, the physiological effects of NO on the beta-adrenergic post-receptor signaling system are unknown. The objective of the present study was to examine the effects of cardiac NO synthase (NOS) inhibition on left ventricular (LV) hemodynamics and mechanoenergetics in response to adenylyl cyclase stimulation in human heart failure. METHODS AND RESULTS: The study group comprised 13 patients with heart failure because of idiopathic cardiomyopathy (IDC). Emax was examined as an index of LV contractility, LV external work (EW), pressure-volume area (PVA), myocardial oxygen consumption (MVO2), and mechanical efficiency (EW/MVO2) with the use of conductance and coronary sinus thermodilution catheters before and during colforsin daropate infusion, and during concurrent infusion of colforsin daropate with the NOS inhibitor, NG-monomethyl-L-arginine (L-NMMA; 200 micromol). Colforsin daropate increased Emax by 53% and EW by 18%, and reduced PVA by 14%, without altering MVO2 or mechanical efficiency. The combination of colforsin daropate with L-NMMA further increased Emax by 26% and reduced PVA by 9%, without altering MVO2 or mechanical efficiency. CONCLUSIONS: These findings suggest endogenous NO may modulate beta-adrenergic post-receptor pathways and preserve myocardial efficiency in patients with IDC.

Sumatriptan provokes coronary artery spasm in patients with variant angina: possible involvement of serotonin 1B receptor.

BACKGROUND: Serotonin (5HT) can induce coronary artery spasm (CAS) in patients with variant angina (VA). We have previously reported that 5HT(1B) and 5HT(2A) receptors gene were expressed in human coronary arterial smooth muscle cells and that isolated coronary artery from a patient with VA showed the supersensitivity to sumatriptan (SMT), a 5HT(1B/1D) receptor agonist. The aim of the present study was to determine whether SMT can provoke CAS directly or indirectly through platelet aggregation in patients with VA. METHODS: We evaluated the effects of intracoronary infusion of graded concentrations of SMT on coronary arteries in 9 patients, including 5 documented VA and 4 participants with atypical chest pain as control. RESULTS: SMT provoked CAS in all patients with VA. SMT could not induce CAS in control. SMT (10(-4) M) caused significant contractions (%diameter of baseline; median [interquartile range], 0 [0-18.4]% in VA, as compared with control (proximal segments; 92.6 [77.9-118.9]%, p<0.05 vs. VA, distal segments; 92.9 [65.3-158.5]%, p<0.01 vs. VA). In control, minor dilation occurred at SMT concentration up to 10(-5) M. SMT could induce in vitro platelet aggregation neither in healthy subjects nor in patients with VA. CONCLUSIONS: These findings suggest that activation of 5HT(1B) receptor by SMT can induce CAS directly in patients with VA without platelet activation. This is the first report directly demonstrating the effect of 5HT(1B) receptor activation on human coronary arteries in vivo.

Pathophysiological characteristics and responsiveness to neurohormonal antagonism in idiopathic dilated cardiomyopathy patients with antihepatitis C virus antibody.

A high prevalence of hepatitis C virus (HCV) infection has been reported among idiopathic dilated cardiomyopathy (DCM) patients. We examined the prevalence of DCM patients with HCV antibody, and the pathophysiological characteristics and responsiveness to neurohormonal antagonism in DCM with HCV. HCV antibodies were determined in 540 patients with cardiac diseases. In 117 DCM patients, clinicopathologic data were evaluated before and 1 year after angiotensin converting enzyme inhibitor and/or beta-blocker (ACE-inhibitor/BB) administration and their prognosis was followed-up for a mean of 72 +/- 41 months. HCV antibodies were found in 12 of 135 DCM patients (8.9%) and in 37 of 405 patients without DCM (9.1%) (P = NS). At baseline, contrary to DCM without HCV, DCM with HCV was associated (P < 0.05) with greater left ventricular (LV) end-diastolic and end-systolic dimension, LV mass, and myocardial diameter in endomyocardial biopsy, and lower % fractional shortening. By multivariate analysis, HCV infection was independently associated with larger LV end-systolic dimension among DCM patients (P = 0.005). The advanced LV dilatation and hypertrophy in DCM with HCV decreased more in response to the ACE-inhibitor/BB therapy compared to DCM without HCV. There were no differences between DCM patients with and without HCV in survival and cardiac event-free rates. In summary, although HCV infection appears not to be the specific cause of DCM, HCV may enhance ventricular remodeling leading to heart failure among DCM patients. Nevertheless, the advanced ventricular remodeling with HCV was adequately reversed by neurohormonal antagonism, and did not lead to an unfavorable outcome.

Depletion of antioxidants is associated with no-reflow phenomenon in acute myocardial infarction.

BACKGROUND: No-reflow phenomenon is observed in approximately one-third of patients after percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI), and is associated with poor functional and clinical outcomes. On the other hand, the formation of free radicals in vasculature exerts deleterious effects on coronary microcirculation. HYPOTHESIS: We hypothesized that redox state in coronary circulation may play a crucial role in no-reflow phenomenon in AMI. METHODS: Consecutive 26 patients with first AMI who underwent primary PCI < 24 h after onset were enrolled. Before PCI, blood samples were obtained from coronary sinus to measure plasma or serum antioxidative vitamins (vitamin C, vitamin E, and beta-carotene) and antioxidative enzymes (extracellular glutathione peroxidase [GPX], superoxide dismutase, and catalase). After PCI, the corrected Thrombolysis In Myocardial Infarction (TIMI) frame count (CTFC) was measured in the target vessel. Patients with TIMI < or = 2 flow despite an optimal PCI result were designated as no-reflow group (Group NR, n = 6) and the others as reflow group (Group R, n = 20). RESULTS: Levels of vitamin C, vitamin E, and GPX before PCI were significantly lower in Group NR than in Group R. The CTFC correlated inversely with levels of vitamin C, vitamin E, and GPX (p < 0.05). CONCLUSIONS: Depletion of antioxidants is associated with no-reflow phenomenon in AMI. These findings strongly suggest that the redox state in coronary circulation plays an important role in the pathogenesis of no-reflow phenomenon.

Attenuation of biologic compensatory action of cardiac natriuretic peptide system with aging.

Although plasma B-type natriuretic peptide (BNP) levels increase with age, the mechanisms responsible for this increase are unknown. We investigated the predictors of elevated BNP in older subjects without cardiac systolic dysfunction and overt renal dysfunction. Furthermore, we analyzed the relations between BNP and its second messenger, cyclic guanosine monophosphate (cGMP), to aging. In 252 subjects (mean age 69 +/- 12 years) with left ventricular ejection fraction >/=50% and creatinine levels <==1.5 mg/dl, plasma levels of BNP, cGMP, blood urea nitrogen, creatinine, and beta2-microglobulin (an endogenous marker of renal function), estimated glomerular filtration rate, and echocardiographic data were prospectively evaluated. Plasma BNP levels increased with age (r = 0.4, p <0.0001). With use of multivariate analysis, predictors of elevated BNP levels were age, use of beta blockers, and serum beta2-microglobulin levels. The molar ratio of cGMP to BNP significantly decreased with aging (r = 0.55, p <0.0001). Elevated BNP in older subjects with normal cardiac systolic function may be due in part to renal impairment. With aging, biologic compensation of the cardiac natriuretic peptide system may be attenuated.

Superoxide generation in directional coronary atherectomy specimens of patients with angina pectoris: important role of NAD(P)H oxidase.

OBJECTIVE: NADH/NADPH oxidase is an important source of reactive oxygen species (ROS) in the vasculature. Recently, we demonstrated that p22(phox), an essential component of this oxidase, was expressed in human coronary arteries and that its expression was enhanced with the progression of atherosclerosis. The present study was undertaken to investigate its functional importance in the pathogenesis of coronary artery disease. For this aim, the expression of p22(phox), the distribution of oxidized low density lipoprotein (LDL), and the generation of ROS in directional coronary atherectomy (DCA) specimens were examined. METHODS AND RESULTS: DCA specimens were obtained from patients with stable or unstable angina pectoris. The distribution of p22(phox) and of oxidized LDL was examined by immunohistochemistry. The generation of superoxide in DCA specimens was assessed by the dihydroethidium method and lucigenin-enhanced chemiluminescence. ROS were closely associated with the distribution of p22(phox) and oxidized LDL. Not only inflammatory cells but also smooth muscle cells and fibroblasts generated ROS. There was a correlation between ROS and the expression of p22(phox) or oxidized LDL. The generation of ROS was significantly higher in unstable angina pectoris compared with stable angina pectoris. CONCLUSIONS: ROS generated by p22(phox)-based NADH/NADPH oxidase likely mediate the oxidative modification of LDL and might play a major role in pathogenesis of atherosclerotic coronary artery disease.