Studies on the selective trifluoroacetolytic scission of native peptaibols and model peptides using HPLC and ESI-CID-MS.

Representative members of a group of linear, N-acylated polypeptide antibiotics (peptaibols) containing alpha-aminoisobutyric acid (Aib) and, in part, isovaline (Iva), as well as proteinogenic amino acids and a C-terminal-bonded 2-amino alcohol, were treated with anhydrous trifluoroacetic acid (TFA) at 37 degrees for 0.5-26 h. The resulting fragments were separated by HPLC and characterized by electrospray ionization collision-induced dissociation mass spectrometry (ESI-CID-MS).

Gas-chromatographic separation of stereoisomers of dipeptides.

Synthetic dipeptides comprising mixtures of enantiomers, diastereomers, or sequential isomers were converted into their N-perfluoroacetyl dipeptide esters (perfluoroacetyl: trifluoroacetyl, pentafluoroacetyl, heptafluorobutyryl; ester: methyl, 1-propyl, 2-propyl, 2,2,2-trifluoroethyl) and analyzed by GC-MS on the chiral stationary phases Chirasil-L-Val and Lipodex-E using helium as carrier gas. Further, dipeptides were converted into their N-trifluoroacetyl dipeptide S-(+)-2-butyl esters and separated on achiral phenylmethyl polysiloxane column (HP-5 MS). Derivatization of dipeptides was performed at ambient temperature in order to avoid formation of the corresponding diketopiperazines.

Complications after total knee arthroplasty: a comprehensive report.

In most reports of complications following TKA, the method of assessment and report of complications is not defined specifically. It is thus unclear whether certain complications did not occur or were simply not assessed at all. A detailed list of possible complications following TKA was developed, and the occurence of complications in 567 primary TKAs was followed up meticulously according to this list for one year postoperatively.

Robotic total knee arthroplasty: the accuracy of CT-based component placement.

Background: Accurate alignment of the components in total knee arthroplasty is important. By use of postoperative CT controls, we studied the ability of a robotic effector to accurately place and align total knee arthroplasty (TKA) components according to a purely CT-based preoperative plan.

Patients And Methods: Robotic TKA was performed in 13 patients (6 men) with primary gonarthrosis.

Repetitive low-energy shock wave treatment for chronic lateral epicondylitis in tennis players.

Background: There is conflicting evidence regarding extracorporeal shock wave treatment for chronic tennis elbow.

Hypothesis: Treatment with repetitive low-energy extracorporeal shock wave treatment is superior to repetitive placebo extra-corporeal shock wave treatment.

Methods: Seventy-eight patients enrolled in a placebo-controlled trial.