Acid-base properties of thymopoietin-type tri- and tetrapeptides and their derivatives.

The submolecular basicities of 21 immuno-modulating, thymopoietin-type di-, tri-, and tetrapeptides were studied and characterized in terms of group constants and partial microconstants. All compounds were derivatives of the H-Arg-Lys-Asp-OH tripeptide. Modifications within four covalent bonds of the basic site (esterification, acylation, curtailment or addition at C-terminal end, exchange of amino acids) cause significant changes in the scheme of protonation and in the individual basicity of proton binding sites.

Executive roundup. Surviving the cash flow crunch.

With today's dual pressures demanding quality health care at more affordable prices, it's little wonder many hospital executives are worried about their institutions' financial health--and even their jobs. Still, many of these officials are trying to keep a positive face on things. In part, they express the hope that creative product supply systems and better overall communication with vendors will generate efficiencies and help offset dwindling reserves.