Dependence of Membrane Tether Strength on Substrate Rigidity Probed by Single-Cell Force Spectroscopy.

Substrate rigidity modulates cell mechanics, which affect cell migration and proliferation. Quantifying the effects of substrate rigidity on cancer cell mechanics requires a quantifiable parameter that can be measured for individual cells, as well as a substrate platform with rigidity being the only variable. Here we used single-cell force spectroscopy to pull cancer cells on substrates varying only in rigidity, and extracted a parameter from the force-distance curves to be used to quantify the properties of membrane tethers. Our results showed that tether force increases with substrate rigidity until it reaches its asymptotic limit. The variations are similar for all three cancer cell lines studied, and the largest change occurs in the rigidity regions of softer tissues, indicating a universal response of cancer cell elasticity to substrate rigidity.

Effect of midfacial distraction on the obstructed airway in patients with syndromic bilateral coronal synostosis.

PURPOSE: Le Fort III osteotomy and midfacial advancement expand the nasopharynx and potentially increase airway dimensions in patients with syndromic bilateral coronal synostosis. Distraction osteogenesis allows greater midfacial advancement, and may offer more improvement in airway obstruction, compared with the conventional 1-stage procedure. This study aimed to document the effect of midfacial distraction-advancement on airway obstruction in patients with syndromic bilateral coronal synostosis. PATIENTS AND METHODS: Charts of patients with syndromic bilateral coronal synostosis who had undergone Le Fort III distraction were reviewed. Preoperative and postoperative demographic, cephalometric, polysomnographic, and subjective patient/parental reported data were reviewed. Descriptive and nonparametric bivariate statistics were computed, to document changes in airway parameters. RESULTS: Of 25 patients who underwent midfacial Le Fort III distraction, only 18 had preoperative airway obstruction. The mean age at operation for patients with airway obstruction was (+/-SD) 10.4 +/- 4.2 years (range, 2.7 to 17.4 years), and the average advancement was 20.5 +/- 7.4 mm (range, 10 to 30 mm). Five of 6 patients with a tracheostomy were decannulated; 1 patient had persistent central apnea that prevented decannulation. The mean respiratory distress index for the group improved from 33.4 +/- 37.57 (range, 1.8 to 109.2) to 12.6 +/- 26.32 (range, 0.00 to 72.0) (P < .05). Six of 9 patients no longer required continuous or bilevel positive airway pressure. All patients reported decreased snoring (P < .05). CONCLUSIONS: Midfacial distraction improves airway obstruction in patients with syndromic bilateral coronal synostosis. Clinicians can counsel patients and families that this procedure usually permits decannulation and discontinuation of continuous or bilevel positive airway pressure.