In oral squamous cell carcinomas of the head and neck, Laminin-5 γ2 has been associated with tissue invasion, lymph node metastasis and histopathological grading. In the present study, we compared the expression of the subunit γ2 of Laminin-5 under normal, dysplastic and invading epithelia in 65 biopsies previously diagnosed for oral squamous cell carcinoma. The number of γ2-positive cells were analyzed in relation to patients' survival, tumor grading, size of the lesion, TNM stage, histopathological pattern of invasion and inflammatory reaction. Biopsies of oral squamous cell carcinomas were deparaffinised, processed for antigen unmasking procedures and stained with antibody anti-Laminin-5 γ2. By light microscopy, 4 optical fields of x200 were selected in three different areas including normal, dysplastic and invading epithelia. Positive cells were counted and divided into three categories, which included <20 cells, between 21 and 50 cells and >50 stained cells. Patient survival was analyzed by Kaplan-Mayer curves. γ2-positive cells were found in the basal layer of dysplastic epithelium, within inflammatory infiltrate, at the margins of differentiated invading islands and at the forefront of undifferentiated invading nests. Observations showed that an increased number of γ2-positive cells correlated significantly with a shorter life expectancy under invading epithelia (log-rank test p<0.05), not when a count was performed under normal or dysplastic epithelia of the same patient. The number of γ2positive cells also correlated with the histopathological pattern of invasion. Our results show that γ2 may be a reliable prognostic tool for oral squamous cell carcinomas.

This paper develops and tests a mathematical model for Na⁺ kinetics applied to standard hemodialysis. The volume of distribution of exchangeable Na⁺, dialyzer surface area, blood and dialysis fluid flow rate, target weight loss, treatment duration and the Na⁺ diffusibility constant are taken into account. The model is used to compute the optimal hour by hour dialysis fluid Na⁺ concentration required to achieve the prescribed end-dialysis natremia and maintain a constant end-dialysis body Na⁺ pool, while providing a nearly uniform removal of Na⁺ over dialysis. The model was preliminarily tested on 10 consecutive dialyses in a single patient using a special dialyzer which generates a part of ultrafiltrate uncontaminated by dialysate.