Critical evaluation of ECV304 as a human endothelial cell model defined by genetic analysis and functional responses: a comparison with the human bladder cancer derived epithelial cell line T24/83.

Early reports indicated that ECV304 was a spontaneously-transformed line derived from a Japanese human umbilical vein endothelial cells (HUVEC) culture. Many morphological, immunochemical, and genetic studies provided further evidence that ECV304 was a valuable biomedical research tool and could be used to study processes that include angiogenesis in vitro and signal transduction by a variety of G protein-coupled receptors. However, several distinct differences between ECV304 and HUVEC are now apparent and recent reports have indicated genetic similarity between ECV304 and T24/83, a human bladder cancer cell line. To further assess the utility of ECV304 as a human endothelial cell model, we compared the functional responses of ECV304 and T24/83 to a range of G protein-coupled receptor agonists. We also used DNA fingerprinting to karyotype both ECV304 and T24/83. Both ATP and uridine triphosphate (UTP) stimulated inositol phosphate metabolism in ECV304 without alteration of cAMP levels. Comparative data using selective P2Y receptor agonists indicated that this response, leading to calcium mobilization from intracellular stores, was predominantly mediated by the activation of P2Y2 receptors. Similar responses were recorded from both ECV304 and T24/83 cells. ECV304 expressed a relatively high basal activity of NOS that was reduced by L-NAME and stimulated by P2Y2 receptor agonists. In contrast, P2Y2 receptor activation did not induce prostaglandin synthesis in ECV304. Both ECV304 and T24/83 express receptors for adenosine, adrenaline, and calcitonin, which stimulate adenylate cyclase. Proliferation of ECV304 and T24/83 cells, measured by the incorporation of [3H]thymidine into DNA, was largely serum-independent. This was in contrast to parallel experiments with porcine and bovine aortic endothelial cells that indicated a marked serum-dependent increase in DNA synthesis. Genetic analysis confirmed that ECV304 and T24/83 are identical. ECV304 displays some endothelial characteristics and is useful for the study of receptor pharmacology. However, ECV304 is not of HUVEC origin and is therefore an inappropriate cell line to study endothelial cell biology.

A simple and accurate mathematical method for calculation of the EC50.

A simple, accurate, and speedy noncomputational technique for the calculation of the EC50 or any other concentration-related parameter of concentration-effect curves is presented. It avoids the necessity for graph construction or computational curve-fitting programs and allows accurate calculation of the EC50, where the value falls between two known concentrations The technique has been applied to a concentration-response curve constructed to hepatic arterial (HA) vasoconstrictor responses to HA injections of noradrenaline in an isolated dual-perfused rat liver preparation. EC50 values calculated by the new technique were compared to those calculated by conventional, established, noncomputational techniques. The new technique is faster, more accurate, and simpler to perform than other established noncomputational techniques used for the calculation of the EC50 and can be widely applied to many other pharmacological investigations.

A randomised trial of fibrin sealant in peripheral vascular surgery.

In a prospective randomised trial 39 patients undergoing either arterial bypass surgery with a polytetrafluoroethylene (PTFE) bypass graft (n = 18) or aortic aneurysm repair with a woven Dacron graft (n = 21) were randomised either to receive fibrin sealant as a topical haemostatic agent at the arterial anastomosis or to act as control. The main outcome measure was the time taken to achieve haemostasis at the suture line. The median time to achieve haemostasis was 0.5 min (range 0-11 min) in the treatment group and 4 min (range 0-21 min) in the control group. This difference was statistically significant p < 0.014 by the Mann-Whitney test. Immediate haemostasis on release of the clamps was achieved in 13/21 patients in the treatment group and in 4/18 patients in the control group (p = 0.023 by Fisher's exact test). There was no difference in total operative time or operative blood loss. No patients in the treatment group suffered any perioperative thromboembolic event and 1 patient in the control group suffered an early graft occlusion. There was no evidence of transmission of hepatitis B or C, or parvovirus B19. In conclusion, fibrin sealant is an effective topical haemostatic agent for arterial suture lines involving PTFE or woven Dacron.

Fibrin sealant reduces suture line bleeding during carotid endarterectomy: a randomised trial.

OBJECTIVES: To determine whether topical fibrin sealant reduced suture line bleeding during carotid endarterectomy with polytetrafluoroethylene (PTFE) patch closure. DESIGN: Prospective randomised non-blinded control trial. SETTING: Regional vascular surgery unit. MATERIALS: Seventeen patients undergoing carotid endarterectomy were randomised either to receive fibrin sealant as a topical haemostatic agent at the arteriotomy suture line or to act as control. OUTCOME MEASURES: Time taken to achieve haemostasis at the suture line. Intraoperative blood loss. Total operative time. RESULTS: The median time to achieve haemostasis was 5.5 min (range 4-31 min) in the treatment group and 19 min (range 10-47 min) in the control group. This difference was statistically significant p < 0.005 by Mann-Whitney test. There was no statistical difference in total operative time. Operative blood loss was lower in the treatment group (median 420ml, range 300-500ml) than in the control group (median 550ml, range 350-1200ml) but this difference was not statistically significant. One patient in the control group suffered a perioperative thrombo-embolic event. CONCLUSION: Fibrin sealant is an effective topical haemostatic agent for arteriotomy suture lines involving PTFE material.

The effects of binder film characteristics on granule and tablet properties.

The physical properties of cast films of four polymers, which are used as binders in tableting, have been determined. Films were equilibrated at different relative humidities and tested both in tension, at three rates of strain, and by the use of indentation to determine creep compliance and hardness of the film under load. Granules and compacts have also been made using the four polymers as binders and the properties of these have been measured. One of the polymers, starch, formed a paste that was difficult to mix adequately. With the other three polymers a positive correlation was found between compact crushing strength and the creep compliance, the ultimate tensile strength and the elongation at fracture of the cast films. A negative correlation was found between the compact crushing strength and the Brinell Hardness of the films.