The chick chorioallantoic membrane (CAM) is a valuable model for evaluating angiogenesis and vasculogenesis. Our purpose was to characterize the formation of the CAM vasculature, in particular the capillary plexus, between days five and six after fertilization and to examine the mode of action of cytochalasin D and suramin on vascular development during this interval. The CAM increased 20-fold in size between days five and six, during which time the capillary plexus forms by both migration of mesodermal blood vessels toward the ectoderm and by the formation of new vessels from angioblasts near the ectoderm. Between days five and six, the CAM becomes thinner, and the density of the mesodermal cells decreases. To determine the mode of action of anti-angiogenic drugs on the day five to day six CAM, various concentrations of cytochalasin D or suramin were added directly to day five CAMs, and their effects were evaluated on day six. Both drugs significantly inhibited CAM growth, altered branching patterns of the major vessels, decreased area of the major vessels, and inhibited the formation of the capillary plexus by inhibiting both vasculogenesis and the migration of mesodermal blood vessels to the ectoderm. Cytochalasin D also inhibited compartmentalization of the plexus. Cytochalasin D and suramin were inhibitory at similar doses. This study provides new information on early CAM development, establishes the mode of action and dose dependency of cytochalasin D and suramin on day five to day six CAMs, and demonstrates that the day five to day six CAM provides a useful assay to examine the effect of anti-angiogenic drugs on blood vessel development, including capillary plexus formation.
INTRODUCTION The purpose of this study was to explore the effectiveness of two chitosan formulations, Omni-Stat ® granules and Celox Gauze ® , in a model of major hepatic injury in the presence of clotting dysfunction. MATERIALS AND METHODS Major hepatic injuries in moderately heparinised swine were treated with either Omni-Stat ® granules or Celox Gauze ® as compared to control plain gauze.RESULTS Plain gauze control failed to stop the bleeding in 13 of 14 attempts. Omni-Stat ® arrested the bleeding in 18 of 18 attempts, providing it was in contact with the bleeding surface. Celox Gauze ® arrested bleeding in 5 out of 6 attempts initially, and with further pressure in the sixth. CONCLUSIONS The results support the evidence that chitosan-derived products act independently of classical clotting pathways and should be effective in patients who suffer major liver injury even in the presence of clotting dysfunctions.
The purpose of this study was to test the hypothesis that components in mainstream (MS) and sidestream (SS) cigarette smoke inhibit growth and angiogenesis using the chick chorioallantoic membrane (CAM). Varying doses of whole or gas-phase MS and SS smoke solutions were placed on day 5 CAMs, and their effects on angiogenesis were evaluated on day 6. All parameters evaluated (CAM area, major blood vessel area, major blood vessel diameter, blood vessel pattern formation, and capillary plexus formation) were inhibited to different degrees in a dose-dependent manner by both MS and SS smoke treatment. Inhibition of growth and vessel development was correlated with inhibition of cell proliferation. Inhibition of capillary plexus formation was caused by failure of mesodermal blood vessels to migrate to the ectoderm. SS smoke solution was more inhibitory than MS smoke solution in all assays, except for capillary plexus formation. In all assays, the toxicants in SS smoke partitioned mainly with the gas phase, whereas those in MS smoke were deduced to be mainly in the particulate phase in the proliferation-dependent assays (CAM area, blood vessel area, blood vessel diameter) and in both the gas and particulate phase in the pattern formation and plexus formation assays. Some of the inhibitory doses of MS and SS smoke solutions had nicotine concentrations within the range found in human smokers. Taken together, these data demonstrate that exposure to complex mixtures of chemicals in MS and SS cigarette smoke adversely affect growth, vessel development, vessel migration, and cell proliferation.
The study supports the evidence that Omni-Stat (Chitosan) acts independently of classical clotting pathways and should be effective in patients with clotting dysfunctions, who suffer major haemorrhage. It also suggests the potential for a role in cardiac surgery.
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