Duodenal ulcer. Discovery of a new mechanism and development of angiogenic therapy that accelerates healing

Inhibitory effects of magnoshinin and magnosalin, compounds from "Shin-i" (Flos magnoliae), on the competence and progression phases in proliferation of subcultured rat aortic endothelial cells

Anti-proliferative effects of magnoshinin and magnosalin derived from "Shin-i" (Flos magnoliae) were investigated using subcultured endothelial cells (EC) of rat aorta. The inhibitory effects of magnoshinin were 2-fold greater at 10 micrograms/ml than that of magnosalin on the increase in cell number when EC were stimulated by 5% fetal bovine serum. In the 3H-thymidine incorporation monitored at 3 hr-intervals, magnoshinin (0.1-3 micrograms/ml) prolonged the starting time of DNA synthesis and reduced the rate of incorporation into EC. Magnosalin (0.3-3 micrograms/ml) reduced only the incorporation rate. These results suggest that magnoshinin inhibits both the competence phase and progression phase, but magnosalin preferentially inhibits the progression phase in EC proliferation.

Binding of heparin to basic fibroblast growth factor induces a conformational change

The binding of heparin to basic fibroblast growth factor (bFGF) induces a small but highly reproducible conformational change observable in the amide I region of the protein's infrared spectrum. The observed spectral changes suggest that the conformational change is highly localized most likely in the beta-turn regions of the bFGF molecule. Heparan sulfate, a component of the endothelial extracellular matrix, was also observed to bind to bFGF and induce a similar conformational change to that observed for heparin. Further, sucrose octasulfate, a compound which mimics the effects of heparin biologically, was also observed to induce this same conformational change. This spectroscopically observable change has allowed us to probe the functional determinants necessary for heparin to bind the bFGF and to induce the observed conformational change. We have determined the effects of binding of various monomeric and polymeric, sulfated and nonsulfated glycosaminoglycans and carbohydrate compounds. The results indicate that the binding of heparin involves highly specific interactions. Further, heparin was observed to greatly increase the thermal stability of bFGF, raising the Tm by 25 degrees C. Sucrose octasulfate was also able to enhance the thermal stability of bFGF, but not to the same extent as heparin.

Control of angiogenesis by heparin and other sulfated polysaccharides

Heparin and its related polysaccharides are revealed to have important new functions as regulators of blood vessel growth and regression. This regulatory activity may be explained in part by at least five mechanisms in which heparin and heparan sulfate interact with peptide growth factors: (1) Heparin and heparan sulfate have a high affinity for angiogenic growth factors such as the fibroblast growth factors and VEGF, as well as for angiogenic inhibitors such as thrombospondin and platelet factor 4. (2) Heparin and its related polysaccharides stabilize bFGF and other growth factors. (3) FGFs and thrombospondin are stored in the extracellular matrix bound to heparan sulfate; fragments of heparin or heparan sulfate may act as natural chaperones to shuttle bFGF or other growth factors to different cellular compartments. (5) Heparin-like low-affinity receptors on the surface of endothelial cells (and other cells), prepare FGFs for binding to their specific high affinity receptors; and (6) Heparin and its related polysaccharides potentiate angiostatic steroids. It is likely that future investigations will uncover even more fundamental regulatory roles for heparin as well as for other polysaccharides in the normal function of growth factors, especially in the complex process of angiogenesis.

Acid secretion, 1932-92: advances, adaptations, and paradoxes

This paper reviews the evolution of our understanding of various aspects of gastric acid secretion over the past 60 years. Embryologic aspects and neonatal acid secretion are considered, and the relationship between parietal cell mass and acid secretion and the changing concepts of parietal cell activation are discussed. The effect of aging on acid secretion and the relevance of acid secretion in health and disease are reviewed, and current views on adaptation to therapeutic inhibition of acid secretion presented. The aetiologic link between acid secretion and ulcer disease is re-examined, and the role of pepsin, growth factors, and Helicobacter pylori briefly considered.