The density and distribution of whole mount BrdU-anti-BrdU labeled endothelial cells (days 6-15) in the chick chorioallantoic membrane (CAM) was analyzed with computer-assisted microscopy. A significant loss of proliferative activity was noted after day 10: the density of labeled nuclei (in 10(-2) mm-2) decreased from a median 7.78 (days 6, 8, 10) to 2.42 (days 12, 14, 15). CAMs initially showed random patterns of labeled endothelial cells, but changed to clearly focal patterns after day 12. A regular arrangement of labeled nuclei was never seen. After application of vascular endothelial growth factor (VEGF) to the day 13 CAM, a significant increase in proliferative activity (11.50) and a random distribution of labeled endothelial cells was observed on day 15. Development of CAM precapillary vessels was assessed in terms of length density (in mm-1, mean +/- standard deviation), which was augmented three-fold from day 6 (1.22 +/- 0.05) to day 14 (3.54 +/- 0.23) and then remained nearly constant. VEGF application from day 13 to 15 raised arterial length per unit area to 4.53 +/- 0.77. It is concluded that normally a local regulation of endothelial proliferation and differentiation develops in the CAM, which doubles capillary endothelial cell density but simultaneously adapts to the decreasing need for endothelial cells, and thus maintains the quasi two-dimensional vessel pattern. However, proliferative foci persist in the capillary layer after day 10, and precapillary vessel density continues to increase until day 14. VEGF enhances DNA synthesis in all capillary endothelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Allantoin↗

PubMed1995

A randomized comparison of intravenous amrinone versus dobutamine in older patients with decompensated congestive heart failure.

OBJECTIVE: To compare the hemodynamic effects of amrinone and dobutamine in patients 75 years of age or older who have severe congestive heart failure requiring invasive hemodynamic monitoring and inotropic support. DESIGN: Prospective, randomized, double-blind clinical trial. SETTING: Coronary care unit of a university teaching hospital. PARTICIPANTS: Fourteen patients > or = 75 years of age (mean 80.3 +/- 5.7 years) with refractory New York Heart Association class IV congestive heart failure. All patients had a cardiac index < 2.5 L/min/M2 (mean 1.8 +/- 0.3 L/min/M2), pulmonary capillary wedge pressure > or = 18 mm Hg (mean 26 +/- 10 mm Hg), and left ventricular ejection fraction < 40% (mean 26 +/- 10%). INTERVENTION: Patients were randomly assigned to treatment with 2-hour infusions of amrinone (n = 7) or dobutamine (n = 7) at fixed dosages of 5 and 10 micrograms/kg/min. MEASUREMENTS: Complete hemodynamic data were obtained at baseline and after each 2-hour medication infusion. Transthoracic two-dimensional echocardiography was performed at baseline and after the 10 micrograms/kg/min medication dose. The primary analysis compared the effects of the two drugs on cardiac index and stroke volume index at each of the two dosages. RESULTS: Both amrinone and dobutamine had salutary hemodynamic effects, as indicated by improvements in cardiac index, stroke volume index, pulmonary capillary wedge pressure, and systemic vascular resistance (all P < .05 except effect of amrinone on stroke index and wedge pressure). Although the overall hemodynamic effects of amrinone and dobutamine were similar, stroke volume index was higher with dobutamine at the 10 micrograms/kg/min dose (35 +/- 7 ml/M2 vs 26 +/- 6 mL/M2; P = .045). Two dobutamine patients were withdrawn from the study after the 5 micrograms/kg/min dose due to adverse effects (tachycardia, increased ventricular ectopy). One additional patient in each group was noted to have ventricular arrhythmias not requiring termination of the protocol. CONCLUSIONS: Both amrinone and dobutamine are efficacious in improving hemodynamics in older patients with severe congestive heart failure caused by left ventricular contractile dysfunction. Despite the effect of aging on beta-adrenergic responsiveness, dobutamine is at least as effective as amrinone but may be associated with a higher incidence of arrhythmic side effects.

Aged↗

PubMed1995

Development of the embryonic vascular system.

In this article, we survey the mechanisms involved in early embryonic angiogenesis. The first embryonic blood vessels are formed exclusively by endothelial cells. Therefore, the emergence and behavior of this cell type is the center of this article. We discuss both intra- and extraembryonic angiogenesis and the various modes of capillary formation. The high plasticity and migratory potential of endothelial cells and their precursors, the angioblists, are outlined. The promoting and inhibiting influences of the extracellular matrix on the behavior of angioblasts are a matter of concern, as is also the question of embryonic angiogenic factors. Cell-cell interactions that may lead to organ-specific differentiation of endothelial cells are mainly discussed in the context of blood-brain barrier formation and development of fenestrated capillaries. The last section deals with the development of the vascular wall.

Animals↗

PubMed1994