Bicuspid Aortic Valve: A Review of its Genetics and Clinical Significance.

The aim of this review was to describe recent advancements in the understanding of bicuspid aortic valve (BAV). BAV is the most common congenital cardiac anomaly, and affects between 0.46% and 1.37% of the population. There is a male predominance of approximately 3:1.While isolated BAV is found in certain patients, it is often associated with other congenital cardiac lesions, including dilatation of the thoracic aorta, coarctation of the aorta and abnormalities of the coronary anatomy. In most cases, it remains undetected until the patient contracts infective endocarditis, or calcification occurs. Alternatively, the BAV may remain functional for the entirety of the subjects' life, or it may develop progressive calcification, stenosis and regurgitation, with or without infection. Additionally, BAV is associated with aortic aneurysm formation and aortic dissection. Because BAV is a disease of both the valve and the aorta, surgical decision-making is complicated and remains an important challenge to the surgeon. Although recent reports have improved the current knowledge of the disease, many questions remain unresolved. The present review summarizes the current knowledge regarding the genetic basis of BAV and highlights some of the recent findings that have shed a light on the complications of this disease.

pH-sensitive micelles loaded paclitaxel using carboxymethyl chitosan-palmitic acid mediated by cRGD / 药学学报

cRGD-carboxymethyl chitosan-palmitic acid (cRGD-CMCh-PA) was synthesized and a pHsensitive paclitaxel-loaded cRGD-CMCh-PA micelles (PTX-cRGD-CMCh-PA) was prepared with the film dispersion method; related substances were characterized by FT-IR and 1H NMR. PTX-cRGD-CMCh-PA micelles were studied with the particle size distribution, zeta potential, morphology and release behavior in vitro was investigated by the method of equilibrium dialysis. In vitro cytotoxicity of different formulations on A549 cells was tested by MTT assay. The uptake process of micelles was explored using confocal microscopy and a live cell station was used to observe the dynamic phagocytosis. The subcutaneous and orthotropic tumor models were built to study the distribution of DiR-labeled micelles by near-infrared fluorescence (NIR) imaging system. The FT-IR spectra and 1H NMR spectra confirmed the successful conjugation of cRGD-CMCh-PA polymer and the degree of carboxymethyl and the palmitic acid grafted on chitosan were 45.0% and 15.0%. PTX-cRGD-CMCh-PA micelles were prepared with particle size of (162.9±1.5) nm, zeta potential of +26.3 mV and encapsulation efficiency and the drug loading of 99.67% and 28.5%, respectively. The micelles released slowly in pH 7.4 whose release curves were accorded with the Higuchi equation; they had an initial burst effect in second hours and showed a pH sensitive release behavior in pH 5.3. The IC50 of PXT-CMCh-PA and PTX-cRGD-CMCh-PA were 2.077 μg·mL-1 and 0.876 μg·mL-1, respectively. The cells uptake process of micelles in A549 cells revealed that the micelles were mainly co-located with lysosome and PTX-cRGD-CMCh-PA showed much better targeting effect. The NIR fluorescence imaging results showed that the micelles had a good targeting effect on both subcutaneous and orthotropic tumors. In this study, a novel copolymer cRGDCMCh-PA was synthesized with a sustained and pH-dependent drug release activity which would potentially become a new carrier for hydrophobic drugs.