Multidimensional stimulus encoding in the auditory nerve of the barn owl.

Auditory perception depends on multi-dimensional information in acoustic signals that must be encoded by auditory nerve fibers (ANF). These dimensions are represented by filters with different frequency selectivities. Multiple models have been suggested; however, the identification of relevant filters and type of interactions has been elusive, limiting progress in modeling the cochlear output.

Chromatographic purification of human alpha 1 proteinase inhibitor from dissolved Cohn fraction IV-1 paste.

A novel chromatographic process for purification of alpha 1 proteinase inhibitor (alpha 1-PI) from Cohn fraction IV-1 paste is described. This process has been successfully scaled up to 50-1 columns. It involves DEAE chromatography, sulfopropyl (S) cation chromatography, tri-n-butyl phosphate (TNBP)-cholate treatment, a second S cation chromatography, freeze-drying and dry-heat.

A highly purified antithrombin III concentrate prepared from human plasma fraction IV-1 by affinity chromatography.

We describe an improved method for large-scale purification of antithrombin III (AT-III) from human plasma involving heparin affinity chromatography of redissolved fraction IV-1 paste, viral inactivation by heating, followed by a second heparin affinity column. The characteristics of a new heparin affinity resin and the ability to extrapolate process behavior from small-scale (20 ml) to large-scale (40 liter) columns are described. This supports the use of the small-scale column for process optimization and validation studies in compliance with current regulatory requirements for biological products.