Separation and characterization of nonphosphorylated and serine-phosphorylated urokinase. Catalytic properties and sensitivity to plasminogen activator inhibitor type 1.

Urokinase synthesized by human A431 epidermoid carcinoma cells is phosphorylated on serine (Mastronicola, M. R., Stoppelli, M. P., Migliaccio, A., Auricchio, F., and Blasi, F. (1990) FEBS Lett. 266, 109-114). To test the possibility that phosphorylation may have specific effects on urokinase function, the phosphorylated and nonphosphorylated forms of urokinase were separated by Fe(3+)-Sepharose chromatography. Both forms exhibit indistinguishable Km and kcat for plasminogen activation. On the other hand, their sensitivity toward the specific plasminogen activator inhibitor type 1 is different as assessed by measuring both the stability of the covalent complex and the residual enzymatic activity. Phosphorylated urokinase was 50% inhibited at a concentration of plasminogen activator inhibitor type 1 4-fold higher than nonphosphorylated urokinase (0.7 versus 0.15 nM). Furthermore about 10% of phosphorylated urokinase was resistant to plasminogen activator inhibitor type 1 at a concentration as high as 20 nM. Thus, phosphorylation affects urokinase sensitivity to plasminogen activator inhibitor type 1, therefore resulting in a net, although indirect, increase of urokinase activity. These results suggest the existence of a novel cellular regulatory mechanism of extracellular proteolysis

Spondylodiscitis after transoral robotic surgery: Retrospective 7-case series from the GETTEC group

International audienceBackground: Cervical spondylodiscitis is a rare but severe complication of pharyngeal surgery.Material and methods: This multicenter retrospective study reported all patients in the database of the French head and neck tumor study group (GETTEC) affected by cervical spondylodiscitis after transoral robotic surgery (TORS) for malignant pharyngeal tumor from January 2010 to January 2017.Objectives: To describe cases of post-TORS cervical spondylodiscitis, identify alarm signs, and determine optimal management of these potentially lethal complications.Results: Seven patients from 6 centers were included. Carcinomas were located in the posterior pharyngeal wall. Tumor stage was T1 or T2. All patients had risk factors for spondylodiscitis. Mean time to diagnosis was 12.6days. The interval between surgery and spondylodiscitis diagnosis ranged from 20days to 4.5months, for a mean 2.1months. The most common symptom was neck pain (87%). Infections were polymicrobial; micro-organisms were isolated in 5 cases and managed by intravenous antibiotics, associated to medullary decompression surgery in 3 cases. Follow-up found favorable progression in 4 cases, and 3 deaths (mortality, 43%).Conclusion: This French multicenter study found elevated mortality in post-TORS spondylodiscitis, even in case of limited resection. Surgeons must be aware of this complication and alerted by persistent neck pain, fever, asthenia, impaired or delayed posterior pharyngeal wall wound healing or elevation of inflammatory markers. MRI is the most effective diagnostic radiological examination