Quantification of the effects of respiration and parallax on inferior vena caval filter position.

Purpose: The change in inferior vena caval (IVC) filter position at follow-up relative to the filter position at implantation has been used as a criterion for evaluation and comparison of these devices. Perceived changes in filter position may be due to respiratory movement and/or changes in parallax between the initial and follow-up imaging studies. In this study the authors evaluated and attempted to quantify the effects of respiratory movement and parallax.

Influence of ligand valency on ligand-influenced monomer-dimer equilibrium systems and biological control mechanisms.

Two specific ligand-influenced monomer-dimer equilibrium systems are discussed. Each has a ligand-to-dimer subunit ratio of 0.5.

Protocols for use of ultrafiltration in determination of free ligand concentration and of complexity of ligand/protein interactions.

Analysis of a simple ligand/binding-protein association model predicts a decrease in the percentage of free hormone during ultrafiltration. Re-analysis of the original data validating ultrafiltration in free-ligand determinations (Sophianopoulos et al., Arch Biochem Biophys 1978;187:132-7) confirms this prediction.