Management of midfoot diabetic neuroarthropathy.

Between 1986 and 1990, we treated 68 patients with diabetes and neuroarthropathy of the midfoot, 21 of whom had bilateral involvement. Patients were managed according to a strict protocol defined by activity of the neuroarthropathy, instability, ulceration, infection, and ischemia. Initial management of acute neuroarthropathy (18 feet) was open reduction and arthrodesis (8), a total-contact cast or brace (9), and amputation (1). All patients with subacute neuroarthropathy (30 feet) were initially treated in a total contact cast. Four of these feet subsequently required amputation, two required arthrodesis, and one required exostectomy. For chronic neuroarthropathy (41 feet), a total-contact cast or a molded orthotic insert with or without bracing was used initially in all feet. Subsequent surgical salvage for this group included arthrodesis (9), plantar exostectomy (6), amputation (2), and abscess drainage (2). Four patients died during this treatment period and 64 patients (85 feet) were evaluated at a mean interval of 3 years (range 1-6 years) after initiation of treatment. This treatment program was found to be successful in 82 of 85 feet treated.

Comparison of lipid/gramicidin dispersions and cocrystals by Raman scattering.

Gramicidin crystals, dimyristoylphosphatidylcholine (DMPC)/gramicidin dispersions, and DMPC/gramicidin cocrystals were examined by Raman scattering to determine lipid/gramicidin stoichiometries and lipid organization. Calibrations of the choline (716-cm-1) and tryptophan (756-cm-1) peaks indicate that the cocrystals contain two lipids for each gramicidin monomer, a result confirmed by chemical analyses of washed crystals. In dispersions with high lipid/gramicidin ratios (e.g., 25:1), the lipid is ordered but becomes increasingly disordered as the gramicidin content is increased. Paradoxically, the DMPC/gramicidin cocrystals have highly ordered lipids that possibly contain no gauche bonds at all, despite their low lipid/gramicidin ratio. In addition, the polypeptide amide I peak position near 1670 cm-1 is found to be independent of the lipid/gramicidin ratio in the complexes and may indicate a beta-helix-type secondary structure at all ratios. However, the amide I peak broadens significantly at low lipid/gramicidin ratios and broadens still further in the cocrystals, suggesting that protein-protein interactions may induce band-broadening distortions of the polypeptide structure.