Presence of starch enhances in vitro biodegradation and biocompatibility of a gentamicin delivery formulation.

The effect of α-amylase degradation on the release of gentamicin from starch-conjugated chitosan microparticles was investigated up to 60 days. Scanning electron microscopic observations showed an increase in the porosity and surface roughness of the microparticles as well as reduced diameters. This was confirmed by 67% weight loss of the microparticles in the presence of α-amylase. Over time, a highly porous matrix was obtained leading to increased permeability and increased water uptake with possible diffusion of gentamicin. Indeed, a faster release of gentamicin was observed with α-amylase. Starch-conjugated chitosan particles are non-toxic and highly biocompatible for an osteoblast (SaOs-2) and fibroblast (L929) cell line as well as adipose-derived stem cells. When differently produced starch-conjugated chitosan particles were tested, their cytotoxic effect on SaOs-2 cells was found to be dependent on the crosslinking agent and on the amount of starch used.

Clinical and echocardiographic risk factors for embolization in the presence of left atrial thrombus.

AIMS: The aim of our study was to evaluate the factors leading to embolization in patients with left atrial thrombi (LAT). With this purpose, we retrospectively analyzed clinical, transthoracic, transesophageal echocardiographic data of patients with LAT in the transesophageal echocardiographic evaluation. METHODS AND RESULTS: One hundred ninety-two patients with LAT not on anticoagulant therapy were divided into two groups according to the presence of prior ischemic stroke. The group with ischemic stroke included more patients with sinus rhythm and less patients with mitral stenosis. They had smaller left atrial diameter, more left atrial appendage spontaneous echo-contrast, higher appendage ejection fraction, and emptying velocity. CONCLUSION: Once the thrombus has been formed, cerebral embolization seems to be higher in patients with relatively preserved appendage ejection fraction and emptying velocity. Presence of atrial appendage spontaneous echo-contrast also favor embolization. Factors leading to embolization seem to differ in some respects from the causes of thrombus formation.

Stunning of the left atrium after conversion of atrial fibrillation: predictor for maintenance of sinus rhythm?

Recurrence of atrial fibrillation (AF) after cardioversion (CV) to sinus rhythm (SR) is determined by various clinical and echocardiographic parameters. The aim of this study was to determine the value of mitral inflow A-wave velocity, performed at 24 hours after CV in estimation of AF recurrence. The study group consisted of 187 consecutive patients with nonvalvular atrial fibrillation, who had been cardioverted to SR from 1998 to 2000. Transthoracic echocardiography was performed in all cases recruited for the study 24 hours after CV. Left atrial (LA) diameter, left ventricular ejection fraction, and mitral inflow A-wave velocity were measured. The patients were evaluated in five groups according to their recurrence time (<30 days, 31-90 days, 91-180 days, 181-365 days, and >365 days). Maintenance of SR was determined to have a negative linear correlation with age (r =-0.97, P = 0.006), LA diameter (r =-0.93, P = 0.02), and AF duration (r =-0.93, P = 0.02), while having a positive linear correlation with mitral inflow A-wave velocity (r = 0.96, P = 0.008). In the maintenance of sinus rhythm, age, LA diameter, and AF duration were not affected from the method of CV, while mitral inflow A-wave velocity was found to be affected with the method of CV. No relationship was determined between mitral inflow A-wave velocity and the maintenance of sinus rhythm in those performed electrical cardioversion, while frequency of recurrence was found to be higher in those with slow mitral inflow A-wave velocity who were performed pharmacological cardioversion (r = 0.89, P = 0.004). In conclusion, age, duration of AF, LA diameter, and the mitral inflow A-wave velocity can be used to predict the maintenance of SR after CV.

Tear in mitral anterior leaflet as a complication of Manouguian's procedure in a woman with an aortic valve prosthesis.

Complications of valve replacement are diverse. In addition to morbidity due to the prosthetic valve itself (e.g. endocarditis, thrombosis), complications due to operative technique may occur in complex cases, as in aortic valve replacement with annular enlargement. Postoperative echocardiography is a simple, non-invasive method to evaluate patients with prosthetic valves. Detailed knowledge of the surgical technique employed and of probable complications is necessary to make an accurate diagnosis. The case is reported of a woman with aortic valve replacement and annular enlargement who had mitral regurgitation due to a tear in the anterior mitral leaflet as a complication of Manouguian's annulus enlargement.

A rare cause of mitral insufficiency: left atrial anomalous band.

Anomalous muscular bands have been seen in the left ventricle and right and left atria. Although the significance of left ventricular false tendons and right atrial anomalous muscular bands have been reported previously, the importance of anomalous muscular bands observed in the left atrium is not clearly defined. They have been found to be associated with Chiari's network, patent foramen ovale, and supraventricular arrhythmias. We describe a left atrial anomalous band causing mitral valve prolapse and mitral regurgitation.

A fatal complication due to radiofrequency ablation for atrial fibrillation: atrio-esophageal fistula.

Treatment of chronic atrial fibrillation with intraoperative radiofrequency ablation is gaining more acceptance in patients with rheumatic valve disease. This article reports a case of fatal atrio-esophageal fistula after radiofrequency ablation in a patient with rheumatic mitral and aortic valve disease with chronic atrial fibrillation.

Utility of dobutamine stress echocardiography in Kawasaki disease: a case report and review of the literature.

Dobutamine stress echocardiography (DSE) has become widely accepted in the evaluation of adult patients with coronary heart disease. There are new challenges about the use of DSE in the pediatric age group to document ischemia. DSE can demonstrate ischemia noninvasively in Kawasaki disease (KD) patients who are candidates for coronary angiography. We wanted to assess the feasibility and the physiologic responses of DSE in a KD patient with coronary aneurysm. The patient had no ischemia in DSE, which was confirmed by coronary angiography showing no stenosis. The literature about DSE use in KD is reviewed.

Quadricuspid aortic valve abnormality associated with aortic stenosis and aortic insufficiency.

Quadricuspid aortic valve is a rare congenital malformation of the aortic valve. Transthoracic 2-dimensional echocardiography can delineate aortic valve and diagnose most quadricuspid aortic valves. This article is a report of a quadricuspid aortic valve associated with aortic stenosis and aortic insufficiency diagnosed by transthoracic echocardiography.