Prevalence, complications and dental management of the oral cancer in the pediatric patients.

INTRODUCTION: The incidence of childhood malignancy is greatest in the 1st year of life, with the second peak to be found at 2-3 years of age. The aim for the study was to investigate the incidence and nature of oral problems occurring in a population of child cancer patients; the other aim was to assess the dental management of the treatment undergoing children. MATERIALS AND METHODS: All child patients between 2 and 15 years old were admitted to the medical hospital for the treatment of newly diagnosed oral cancer over a period of 1 year were included in the study. Hundred children, 50 males and 50 females were examined in the study. Out of the 100 children, 65 children who confirmed; with the diagnosis of oral cancer were included in the study. RESULTS: Twenty children were found to have untreated dental caries at their initial dental screening; five children required dental extractions before chemotherapy. Fifty of the children in the study group did develop oral problems at some stage after their admission to the hospital. CONCLUSIONS: The delay before diagnosis varies from few weeks to approximately 10 months. Children seem particularly susceptible to the stomatotoxic effects of chemotherapy, and therefore, warrant special attention in preventing and treating these problems.

Traction cytometry: regularization in the Fourier approach and comparisons with finite element method.

Traction forces exerted by adherent cells are quantified using displacements of embedded markers on polyacrylamide substrates due to cell contractility. Fourier Transform Traction Cytometry (FTTC) is widely used to calculate tractions but has inherent limitations due to errors in the displacement fields; these are mitigated through a regularization parameter (γ) in the Reg-FTTC method. An alternate finite element (FE) approach computes tractions on a domain using known boundary conditions. Robust verification and recovery studies are lacking but essential in assessing the accuracy and noise sensitivity of the traction solutions from the different methods. We implemented the L2 regularization method and defined a maximum curvature point in the traction with γ plot as the optimal regularization parameter (γ*) in the Reg-FTTC approach. Traction reconstructions using γ* yield accurate values of low and maximum tractions (Tmax) in the presence of up to 5% noise. Reg-FTTC is hence a clear improvement over the FTTC method but is inadequate to reconstruct low stresses such as those at nascent focal adhesions. FE, implemented using a node-by-node comparison, showed an intermediate reconstruction compared to Reg-FTTC. We performed experiments using mouse embryonic fibroblast (MEF) and compared results between these approaches. Tractions from FTTC and FE showed differences of ∼92% and 22% as compared to Reg-FTTC. Selection of an optimum value of γ for each cell reduced variability in the computed tractions as compared to using a single value of γ for all the MEF cells in this study.

TGF-ß induces changes in breast cancer cell deformability.

Mechanical properties of cells are shown to regulate cell behaviors leading to phenotypic changes that may aid in the development and progression of disease. In this study, we used atomic force microscopy (AFM) indentation with a spherical probe to characterize the elastic and viscoelastic properties of invasive (MDA-MB-231) and noninvasive (MCF-7) breast cancer cells treated with transforming growth factor-ß (TGF-ß). We also used confocal fluorescence imaging to investigate the sub-membrane cytoskeletal structure of the cells. Results showed significant alterations in moduli of both cell types after 24 h TGF-ß treatment which had a context dependent response; moduli for MDA-MB-231 decreased whereas MCF-7 demonstrated stiffening response. Stress relaxation tests showed increased fluid-like nature of MDA-MB-231 following TGF-ß treatment and lower fluidity for MCF-7 cells. We also observed significant alterations in the expression and orientation of actin stress fibers with TGF-ß treatment which correlated with the changes in cell mechanics. Less invasive MCF-7 cells had a delayed overall increase in cell deformability after 48 h exposure to TGF-ß; a similar trend was observed for MDA-MB cells. These changes may be important to facilitate migration, for instance, during metastasis of cancer cells through submicron sized spaces.

Games and teams with shared constraints.

Energy systems of the future are envisaged to encompass multiple interacting autonomous entities. The theory of games provides the foundations for the design and analysis of such systems. This paper reviews models and results that would be of use for such analysis. Classically, games have involved players whose strategies are coupled only through the dependence of utility functions on strategies of other players. However, in many practical settings in the energy domain, system-level limitations bind the choices players can make. In 1965, Rosen (Econometrica33, 520-534 (doi:10.2307/1911749)) pioneered the study of a class of games where there is a common constraint, called a shared constraint, that couples the strategies available to the players. We discuss how this seemingly benign extension has important ramifications, ranging from the very definition of an equilibrium concept, to other key issues such as existence, uniqueness and efficiency of equilibria. We show how the presence of a shared constraint naturally leads to notions of a price and forms the motivations for more recent models. Although most of the paper has the character of a survey, occasionally we also prove new results.This article is part of the themed issue 'Energy management: flexibility, risk and optimization'.

Advancing Edge Speeds of Epithelial Monolayers Depend on Their Initial Confining Geometry.

Collective cell migrations are essential in several physiological processes and are driven by both chemical and mechanical cues. The roles of substrate stiffness and confinement on collective migrations have been investigated in recent years, however few studies have addressed how geometric shapes influence collective cell migrations. Here, we address the hypothesis that the relative position of a cell within the confinement influences its motility. Monolayers of two types of epithelial cells--MCF7, a breast epithelial cancer cell line, and MDCK, a control epithelial cell line--were confined within circular, square, and cross-shaped stencils and their migration velocities were quantified upon release of the constraint using particle image velocimetry. The choice of stencil geometry allowed us to investigate individual cell motility within convex, straight and concave boundaries. Cells located in sharp, convex boundaries migrated at slower rates than those in concave or straight edges in both cell types. The overall cluster migration occurred in three phases: an initial linear increase with time, followed by a plateau region and a subsequent decrease in cluster speeds. An acto-myosin contractile ring, present in the MDCK but absent in MCF7 monolayer, was a prominent feature in the emergence of leader cells from the MDCK clusters which occurred every ~125 µm from the vertex of the cross. Further, coordinated cell movements displayed vorticity patterns in MDCK which were absent in MCF7 clusters. We also used cytoskeletal inhibitors to show the importance of acto-myosin bounding cables in collective migrations through translation of local movements to create long range coordinated movements and the creation of leader cells within ensembles. To our knowledge, this is the first demonstration of how bounding shapes influence long-term migratory behaviours of epithelial cell monolayers. These results are important for tissue engineering and may also enhance our understanding of cell movements during developmental patterning and cancer metastasis.

Comparing the antiplaque efficacy of 0.5% Camellia sinensis extract, 0.05% sodium fluoride, and 0.2% chlorhexidine gluconate mouthwash in children.

BACKGROUND: Dental caries is a multifactorial disease which requires a susceptible host, a cariogenic microflora, and a suitable substrate that must be present for a sufficient length of time. Tea is prepared by the infusion of dried leaves of the tea plant, Camellia sinensis, which contains bioactive compounds like polyphenols, flavonoids, and catechins that are thought to be responsible for the health benefits that have traditionally been attributed to tea. These compounds have multidimensional effects such as antibacterial action, inhibitory action on the bacterial and salivary amylase, and inhibition of acid production. AIMS: The aim of this study is to compare the antiplaque efficacy of 0.5% C. sinensis extract, 0.05% sodium fluoride, and 0.2% chlorhexidine gluconate mouthwash in children. MATERIALS AND METHODS: A randomized blinded controlled trial with 60 healthy children of age group 9-14 years was carried out. The subjects were randomly assigned to three groups, i.e. group A - 0.2% chlorhexidine gluconate, group B - 0.05% sodium fluoride, and group C - 0.5% C. sinensis extract, with 20 subjects per group. Plaque accumulation and gingival condition were recorded using plaque index and gingival index. Oral hygiene was assessed by simplified oral hygiene index (OHIS). Salivary pH was assessed using indikrom pH strips. Plaque, gingival, and simplified OHI scores as well as salivary pH were recorded at baseline, immediately after first rinse, after 1 week, and in the 2(nd) week. STATISTICAL ANALYSIS USED: The data were analyzed using a computer software program (SPSS version 17). Analysis of variance (ANOVA) tests were used to identify significant differences between the means of the study groups. Finally, paired t-tests were used to assess the significance of changes within each group between time periods. Critical P values of significance were set at 0.05 and the confidence level set at 95%. RESULTS: Mean plaque and gingival scores were reduced over the 2-week trial period in the experimental groups. Antiplaque effectiveness was observed in all groups, the highest being in group C (P < 0.05). Chlorhexidine gluconate and tea showed comparative effectiveness on gingiva better than sodium fluoride (P < 0.05). The salivary pH increase was sustained and significant in groups B and C compared to group A. Oral hygiene improvement was better appreciated in groups A and C. CONCLUSIONS: The effectiveness of 0.5% C. sinensis extract was more compared to 0.05% sodium fluoride and 0.2% chlorhexidine gluconate mouth rinses. It should be explored as a cost-effective and safe long-term adjunct to oral self-care of patients as it has prophylactic benefits with minimum side effects.