Directional Migration of MDA-MB-231 Cells Under O2/pH Gradients.

We hypothesized that cancer cells actively migrate toward intratumor microvessels, guided by tissue gradients of metabolic substrates (such as O2) and/or metabolites (such as CO2/H+). To test this hypothesis, we developed an in vitro model in which cellular energy metabolism establishes gradients of O2/nutrient/metabolite in monolayer cells cultured in a conventional culture dish. When gradients of O2 ranging from 3% to ~0% were produced, MDA-MB-231 cells located at 300, 500 and 1500 µm downstream in the gradient demonstrated significant directional migrations (Rayleigh z test). We also found a similar directionality in cell migration at the same location even when the initial O2 level in the O2 gradient was raised from 3% to 21%. Interestingly, such directionalities were no longer demonstrated when the cell density was lowered from 1.8 × 106 to 0.9 × 106 cells/ml. In the former, the magnitude of the extracellular pH gradient in regions 300 and 500 µm downstream in the gradient was significantly larger. Thus, the direction of cell migrations appeared to depend on the gradient of extracellular pH rather than on O2.

Comparison of fast spin-echo and conventional spin-echo magnetic resonance spinal imaging techniques in four normal dogs.

Various magnetic resonance (MR) imaging techniques have been used to assess lumbar spinal abnormalities in people. Four, young adult, clinically normal dogs were used to compare images of the spinal cord acquired using conventional spin-echo and rapid acquisition relaxation-enhanced (RARE), commonly called fast spin-echo (FSE), magnetic resonance imaging techniques. Lateral myelograms were made as an anatomic control. The T2-weighted FSE technique was characterized by better image quality than the T2-weighted conventional spin-echo technique. The short acquisition time with the FSE technique allowed increases in the matrix size and number of excitations, thus improving resolution and signal-to-noise ratio. In canine lumbar spinal MR imaging, use of a FSE technique is recommended to reduce the overall time for imaging and to improve image quality.

Effects of left intraatrial infusion of prostaglandin E1 after open-heart surgery.

The hemodynamic effects of a left intraatrial infusion of prostaglandin E1 (PGE1) given to ten patients after open-heart surgery (LA group), were compared with those following no treatment in a control group of ten patients, and to those following a right intraatrial infusion given to another ten patients (RA group). PGE1 was infused at a rate of 0.03 microgram/kg/min in the RA group and at 0.003 microgram/kg/min in the LA group, and hemodynamics were measured immediately after surgery, then 3, 6, and 12 h after the PGE1 infusion was commenced. The heart rate, right atrial pressure, left atrial pressure, and mean pulmonary arterial pressure remained almost unchanged in all three groups; however, the mean radial arterial pressure and systemic vascular resistance index decreased, and the cardiac index increased in the RA and LA groups. The pulmonary vascular resistance index decreased only in the LA group. Thus, a much smaller dose of PGE1, being one-tenth of that used for the right atrial infusion, administered directly into the left atrium yielded almost the same hemodynamic effects as the larger dose infused into the right atrium. Furthermore, this method of infusing PGE1 is safe, efficacious, and cost-efficient.

Development of a fistula between an internal mammary artery graft and the pulmonary vasculature following coronary artery bypass grafting: report of a case.

We report herein the rare case of a 56-year-old man who gradually developed congestive cardiac failure 6 months after undergoing coronary artery bypass grafting and was found to have a fistula between the internal mammary artery and the pulmonary artery of the upper lobe diagnosed by selective left internal mammary arteriogram. A second sternotomy was performed and demonstrated dense adhesion between the fissure surrounding the internal mammary artery and the upper lobe, and the fistula was resected. We believe that the patient's increasing cardiac failure was almost certainly caused by coronary seal.

[Patch angioplasty for isolated ostial stenosis of the left coronary artery].

Two patients with isolated coronary ostial stenosis were successfully treated by patch angioplasty. These two cases were compared angiographically with 49 conventional CABGs for distal coronary stenosis. The patch angioplasty of the ostium can create an large internal diameter, prevent competitive flows, and can be made under limited dissection at reoperation. For isolated coronary ostial stenosis this method is superior to the CABG to the left anterior descending and/or circumflex coronary arteries in which retrograde flow or stasis may occurred.