Reliability of the pre-operative imaging to assess neck nodal involvement in oral cancer patients, a single-center study

Background: Primary sites for the metastasis of oral cancer are the cervical lymph nodes. Although there has been considerable technical advancement in the radiological imaging, capability to recognize all metastatic lymph nodes pre-operatively has remained as a challenge. Thus elective neck dissection (END) has remained as reli-able practice to treat cervical lymph nodes. This study evaluated the accuracy of pre-operative imaging in pre-operative diagnostics of cervical lymph node status using computed tomography or magnetic resonance imaging in patients with oral squamous cell carcinoma (OSCC). We have also considered the reasons for the difficulties to recognise metastatic nodes in cervical area. Material and Methods: Patient charts of patients who had had elective neck dissection as a treatment for primary OSCC in the Department of Oral and Maxillofacial Surgery, Helsinki University Hospital between 2016 and 2017 were assessed retrospectively. The outcome variable was post-operatively histologically confirmed lymph node metastasis in the neck area. The primary predictor variable was radiologically confirmed metastasis in the neck area. The explanatory variables were age, sex, pT-class, imaging modality, delay and location of the tumour. De-scriptive statistics, sensitivity, specificity and Youden-J index were computed. Results: Eighty-three patients were included in the study. The sensitivity to detect pathological lymph nodes was 44.8%, and the specificity for the examination was 87.0%. 19.3% of cN0 patients had metastasis in the cervical nodes, whereas of the cN+ patients 8.4% were actually pN0. Patients having cN0, the largest neck metastasis was over 10 mm in 12.5%, whereas cN1-3 patients the corresponding rate was 45.5%. The computational threshold to diagnose a metastatic node was 7 mm. Conclusions: Especially small metastases are difficult to diagnose. Limitations of radiological diagnostics must be considered when treating OSCC.Peer reviewe

Comparison of the Effects of Surface Tension and Osmotic Pressure on the Interfacial Hydration of a Fluid Phospholipid Bilayer

The effects of three so-called kosmotropic solutes, namely, betaine, sucrose, and choline chloride on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine large unilamellar vesicles, were studied by measuring the generalized polarization (GP) for the fluorescence emission of the membrane partitioning probe Laurdan. The latter has been shown to be sensitive to the depth of water penetration into phospholipid bilayers. At equal osmotic pressures the three solutes produced different increments in GP, with a qualitative positive correlation. However, the increments in GP correlated also quantitatively with the increase of air-water surface tension caused by the three kosmotropes. Our findings suggest surface tension to determine the impact of these solutes on the lateral packing of the lipid bilayer. Based on the changes in area/lipid at different surface tensions, the equilibrium lateral pressure for a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayer at 25°C was estimated to be ∼34 mN/m