Approaches to Construction of the Medium-Sized Ring Structure in Zetekitoxin AB by Ring-Closing Metathesis.

Zetekitoxin AB (ZTX), a member of the saxitoxin (STX) family isolated from the Panamanian golden frog , shows extremely potent Na-inhibitory activity. Here, we investigate the synthesis of 12-membered ring structure with the C11 tertiary hydroxyl group in ZTX by means of the Mislow-Evans rearrangement reaction and subsequent ring-closing metathesis reaction. Although this approach did not provide access to the 12-membered macrocycle, we obtained a new STX analog with an 18-membered macrolactam structure as a synthetic mimic of ZTX.

Prevalence and clinical characteristics of degenerative mitral stenosis.

Background: Degenerative mitral stenosis (DMS) is found in the elderly population. However, there are a few reports regarding the prevalence rate of DMS and, its clinical characteristics. The aim of this study was to determine the relationship between age, gender, and the prevalence rate of DMS.

Three-dimensional transesophageal echocardiography in the diagnosis of atrial septal aneurysm with patent foramen ovale in a patient with ventricular septal defect.

We present a case of a rare combination of ventricular septal defect and atrial septal aneurysm (ASA) with a patent foramen ovale (PFO) in a 57-year-old female. She was referred to our hospital for the treatment of irregular palpitation and exertional shortness of breath. Two-dimensional transesophageal echocardiography (2D-TEE) with color Doppler imaging demonstrated an ASA with two lines of shunt flows.