Improved High-Frequency Ultrasound Corneal Biometric Accuracy by Micrometer-Resolution Acoustic-Property Maps of the Cornea.

Purpose: Mapping of epithelial thickness (ET) is useful for detection of keratoconus, a disease characterized by corneal thinning and bulging in which epithelial thinning occurs over the apex. In prior clinical studies, optical coherence tomography (OCT) measurements of ET were systematically thinner than those obtained by 40-MHz high-frequency ultrasound (HFU) where a constant speed of sound () of 1636 m/s was used for all corneal layers. The purpose of this work was to study the acoustic properties, that is, , acoustic impedance (), and attenuation () of the corneal epithelium and stroma independently using a scanning acoustic microscope (SAM) to investigate the discrepancy between OCT and HFU estimates of ET.

[Cycloartane triterpenoid of Cimicifuga foetida].

Objective: To study cycloartane triterpenoid of Cimicifuga foetida and their osteoclast inhibition activity.

Method: The compounds were isolated and purified by normal and reversed phase column chromatographic methods. Structures were identified by spectroscopic analyses.

A triterpene glycoside from black cohosh that inhibits osteoclastogenesis by modulating RANKL and TNFalpha signaling pathways.

Osteoporosis is a major age-related source of morbidity and mortality. Increased bone resorption mediated by osteoclasts is central to its pathogenesis. Cytokines, particularly RANKL and TNFalpha, are often increased under pathologic conditions, leading to enhanced osteoclastogenesis.

Cimicifugadine from Cimicifuga foetida, a new class of triterpene alklaoids with novel reactivity.

[structure: see text] An unprecedented triterpene alkaloid glycoside, designated cimicifugadine (1), with a pyridine ring incorporated to a cycloartane triterpenoid nucleus, was isolated from the roots of Cimicifuga foetida. Its structure was established on the basis of extensive spectroscopic measurements and chemical transformation with the absolute configuration at C-24 determined to be S by a modified Mosher method. It demonstrated a novel reactivity in mild acidic media whereby the cyclopropane ring is opened followed by the formation of two isomeric conjugated trienes.