AC5 Surgical Hemostat™ as an effective hemostatic agent in an anticoagulated rat liver punch biopsy model.

Intra-operative and postoperative bleeding is a major concern in surgical procedures for patients taking anticoagulant medications, or where anticoagulants are used to prevent potential life-threatening embolic complications. Heparin is the anticoagulant used most frequently and has an immediate effect on blood clotting, lasting 4 to 6h. Although synthetic self-assembling peptides have been shown to achieve rapid hemostasis in small animals, none have adequately addressed the potential for hemostasis in the presence of anticoagulant therapy in-vivo. Our goal was to investigate the hemostatic activity of a known synthetic self-assembling peptide in animals treated and untreated with heparin anticoagulation therapy. Using a rat liver puncture model, animals were treated with known synthetic peptide AC5 Surgical Hemostatic Device™, or saline controls. Time-to-hemostasis and coagulation times were recorded in both heparinized and non-heparinized animals. Here we show that AC5™ was able to achieve rapid hemostasis equivalently in both heparinized and non-heparinized animals. FROM THE CLINICAL EDITOR: Intra-operative and postoperative bleeding is a major concern in surgical procedures for patients taking anticoagulant medications. In this work the effective hemostasis was demonstrated both in heparinized and non-heparinized animals using self-assembling peptides.

An experimental validation method for questioning techniques that assess sensitive issues.

Studies addressing sensitive issues often yield distorted prevalence estimates due to socially desirable responding. Several techniques have been proposed to reduce this bias, including indirect questioning, psychophysiological lie detection, and bogus pipeline procedures. However, the increase in resources required by these techniques is warranted only if there is a substantial increase in validity as compared to direct questions. Convincing demonstration of superior validity necessitates the availability of a criterion reflecting the "true" prevalence of a sensitive attribute. Unfortunately, such criteria are notoriously difficult to obtain, which is why validation studies often proceed indirectly by simply comparing estimates obtained with different methods. Comparative validation studies, however, provide weak evidence only since the exact increase in validity (if any) remains unknown. To remedy this problem, we propose a simple method that allows for measuring the "true" prevalence of a sensitive behavior experimentally. The basic idea is to elicit normatively problematic behavior in a way that ensures conclusive knowledge of the prevalence rate of this behavior. This prevalence measure can then serve as an external validation criterion in a second step. An empirical demonstration of this method is provided.