Reconstruction of the Achilles tendon and overlying soft tissue using antero-lateral thigh free flap.

Reconstruction of combined loss of the Achilles tendon and overlying soft tissue was performed using an antero-lateral thigh free flap in three patients. The cutaneous portion is used to cover the open wound, and a piece of fascia lata is utilised to replace the missing segment of the Achilles tendon. The skin defect ranged from 5 x 2.5 to 7 x 5 cm, and the tendon loss measured from 3.5 to 5.5 cm in length. All of the patients showed satisfactory functional results with a follow-up period from 3 to 9 months. The advantages of the procedure are that: it is a single-staged operation; it promotes rapid healing of the tendo Achilles since the tendon substitute is well vascularised; it is adaptable to a wide range of defect sizes and shapes; it can be performed in the supine position without the need for postural change; and it can restore good contour and causes minimal morbidity at the donor site.

Compounds capable of generating singlet oxygen represent a source of artifactual data in scintillation proximity assays measuring phosphopeptide binding to SH2 domains.

We developed scintillation proximity assays (SPA) to discover compounds which inhibit phosphopeptide binding to Src homology 2 (SH2) domain proteins Grb2 and Syk. An assay artifact is reported here as a caveat to others. The SPA used an antibody to couple glutathione-S-transferase SH2 domain fusion proteins to scintillant beads coated with protein A. A pyrazoloquinolone and indolocarbazole inhibited [3H]phosphopeptide binding in both assays. Their potency in the SPA increased with prolonged (2 to 24 h) assay exposure to ambient light. They were inactive in absence of light and in an alternate binding assay. Both compounds absorbed visible light and generated singlet oxygen based on 2-methylfuran-trapping experiments. Their inhibitory activity was suppressed by the singlet oxygen scavengers sodium azide and dithiothreitol. The results suggest that compounds, not previously considered photosensitizers, generated enough singlet oxygen to damage oxidant-sensitive SPA components. Therefore, this SPA should be protected from light to minimize occurrence of false positives.