Disposable baby wipes: efficacy and skin mildness.

The results of a series of four clinical studies demonstrated that disposable baby wipes were milder to the skin than use of a cotton washcloth and water, recognized as a "gold standard" for skin mildness. Importantly, the baby wipes caused no significant change from the baseline value in any of the skin parameters examined. This observation verified that the test wipes are minimally disruptive to the epidermal barrier and thus suitable for use on intact or compromised, irritated skin.

The reconstituted mitochondrial adenine nucleotide translocator: effects of lipid polymorphism.

This study investigates the role of polymorphic or nonbilayer lipids in the function of an integral membrane protein which is a key component of the mitochondrial energy transduction apparatus. The adenine nucleotide translocator (AdNT) has been isolated from rat heart mitochondria and reconstituted into ATP-containing liposomes composed of dioleoylphosphatidylcholine (DOPC), dioleoylphosphatidylethanolamine (DOPE), and cardiolipin (CL). CL content was held constant at 11.1 mol%; the ratio of DOPC:DOPE was varied to manipulate R0, the intrinsic radius of curvature of the bilayer [S. M. Gruner (1985) Proc. Natl. Acad. Sci. USA 82, 3665-3669]. Translocator activity was determined fluorometrically, using a coupled enzyme system to measure ADP-induced efflux of ATP. Specific activity was calculated based on the number of functional translocators in each preparation, quantified using the tight-binding inhibitor carboxyatractylate (CAT). AdNT specific activity was a smooth function of R0, with a maximum at a lipid composition similar to that of the inner mitochondrial membrane. Protein incorporation was constant at DOPC:DOPE ratios > 1, but appeared to increase at ratios < or = 1. The fraction of reconstituted AdNT incorporated in the native mitochondrial orientation, estimated from inhibition by 10 microM CAT, was independent of lipid composition and > 85%. Leakage of encapsulated ATP increased at low R0 values both in the presence and absence of protein.

Use of carboxyatractylate and tight-binding inhibitor theory to determine the concentration of functional mitochondrial adenine nucleotide translocators in a reconstituted system.

The adenine nucleotide translocator (AdNT) has been isolated from rat heart mitochondria and reconstituted into liposomes containing ATP. Translocator activity was determined using a coupled enzyme system to measure the ADP-induced efflux of ATP from the liposomes. In order to determine specific activity, the number of functional translocators must also be known. Carboxyatractylate (CAT) is a highly selective inhibitor of the AdNT, with Ki < 10 nM, a value sufficiently low relative to the concentration of protein in transport assays to suggest the use of tight-binding inhibitor theory to quantify functional translocators. Ackermann-Potter plots of velocity vs proteoliposome concentration at several different CAT concentrations were used both to demonstrate the occurrence of tight-binding inhibition and to determine the concentration of AdNT catalytic sites in the native orientation. The results obtained agreed well with earlier reports based on [14C]CAT binding; functionally reconstituted AdNT represented 5-10% of the protein added to the system. Specific activities were ca. 7-10 mumol/min mg depending on the lipid composition of the liposomes. Unincorporated protein did not appreciably affect the measurements. This methodology should be readily applicable to any reconstituted systems for which high-affinity inhibitors which bind only to active protein are known.