Estrogen sulfotransferase (EST) is the sole sulfotransferase expressed in normal human breast epithelial cells and has an important function in determining free estrogen hormone levels in these cells. In the present study we examined the inhibitory effect of the dietary polyphenols quercetin and resveratrol on EST activity, i.e. 17beta-estradiol (E2) sulfation. Both the compounds potently inhibited recombinant human EST in a competitive fashion with K(i) values of about 1 microM. In fact, both polyphenols could serve as substrates for EST. In order to extend the studies to more physiologically relevant conditions, we examined whether inhibition of EST also occurred in the intact cultured human mammary epithelial (HME) cells. The mean baseline EST activity (E2 sulfate formation) in the HME cells was 4.4 pmol/h per mg protein. The IC(50) for resveratrol was very similar to that for recombinant EST, i.e. about 1 microM. Surprisingly, quercetin was 10 times more potent in the HME cells with an IC(50) of about 0.1 microM, a concentration that should be possible to achieve from the normal dietary content of this flavonoid.

Breast↗

PubMedDate not supplied

Development of a miniature intraventricular axial flow blood pump.

A new intraventricular axial flow blood pump has been designed and developed as a totally implantable left ventricular assist device (LVAD). This pump consists of an impeller combined with a guide-vane, a tube housing, and a DC motor. The pump is introduced into the LV cavity through the LV apex, and the outlet cannula is passed antegrade across the aortic valve. Blood is withdrawn from the LV through the inlet ports at the pump base, and discharged to the ascending aorta. Our newly developed axial flow pump system has the following advantages: 1) it is a simple and compact system, 2) minimal blood stasis both in the device and the LV cavity, 3) minimal blood contacting surface of the pump, 4) easy accessibility with a less invasive surgical procedure, and 5) low cost. A pump flow > 5 L/min was obtained against 100 mmHg differential pressure in the mock circulatory system. The pump could produce a passive pulsatile flow effect with a beating heart more efficiently than other non-pulsatile pumps because of minimal pressure drop and inertia along the bypass tract. Anatomic fit studies using dissected hearts of dilated cardiomyopathy (DCM) cadavers showed that this pump could smoothly pass through the aortic valve without any interference with mitral valve function. Recently, a dynamic pressure groove bearing and a miniature lip seal have been developed. The dynamic pressure groove bearing has a simple structure and acts as a pressure resistant sealing mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomyopathy, Dilated↗