A new approach to the direct sequencing of oligopeptides in complex mixtures is described. Mixtures of [2Ho]/[2H3]-N-acetylated and N,O-permethylated peptides are analyzed by collision activate dissociation on a triple quadrupole mass spectrometer using isobutane chemical ionization. Analysis of the collision activated dissociation spectra enables peptide sequences to be deduced. Use of electron capture negative chemical ionization for the sequence analysis of neuropeptides at the picomole level is also described.
A multiphase biomechanical study was performed using human tibialis anterior tendons and cuboid bones, comparing the fixation of the tendon to the bone using bone anchors and bone tunnels. Twenty-six specimens were tested for ultimate load to failure comparing Mitek Superanchor fixation with no. 1 and no. 5 braided polyethelyne suture to bone tunnel fixation. Mitek Superanchor with no. 5 suture failed at 223 N, compared with Mitek Superanchor with no. 1 suture at 134 N and bone tunnel at 143 N (P = 0.033). Mitek with no. 1 suture versus bone tunnel was not significantly different. The Mitek with no. 5 suture failed at the tendon/suture interface (75%), the Mitek with no. 1 suture failed at the suture/anchor interface (56%), and bone tunnel fixation failed most commonly by fracture of the tunnel (76%). This study is the first biomechanical analysis of the pullout strengths of bone tunnels or suture anchors in the cuboid bone. We have shown that the suture anchor has a pullout strength comparable or superior to a conventional bone tunnel in an in vitro situation. We believe it is a viable alternative to fixation of the tibialis anterior tendon to the cuboid when there is insufficient tendon length or failure of the bone tunnel.
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