Reliability and reproducibility of the method of assessment of midpalatal suture maturation: A tomographic study

Objectives:To assess reliability and reproducibility of the individual assessment of midpalatal suture maturation in computed tomography among orthodontists and radiologists for potential diagnosis application.Materials and Methods:Sixty axial slices from cone-beam computed tomography and multi-slice CT scans of patients aged between 11 and 21 years old (33 females and 27 males) were selected. For the investigation of reliability and reproducibility of the method, two groups of examiners were established. The first group consisted of 11 orthodontists and the second consisted of 10 radiologists. Each group examined the images and performed individual assessment of the midpalatal suture maturation method twice within an interval of 21 days. During the first and second analyses, the sequence of images was randomized to reduce potential bias. Weighted Cohen''s kappa was performed to assess inter- and intra-examiners'' agreement. The percentage of perfect agreement and the number of stages apart for each disagreement were calculated. The significance level was P < .05.Results:The overall inter-examiner agreement was satisfactory in the first (kappa_w: 0.37) and the second (kappa_w: 0.34) analyses. Intra-examiner agreement outcomes were similar between orthodontists (kappa_w: 0.44) and radiologists (kappa_w: 0.41). The percentage of perfect agreement was 43.2%.Conclusions:The method for individual assessment of midpalatal suture maturation revealed potential reliability and reproducibility. However, the agreement rate observed in the present study was not high enough for a method designed for routine clinical applications.     

Epithelial–mesenchymal transition and cancer stem cells: A route to acquired cisplatin resistance through epigenetics in HNSCC

Chemoresistance is associated with tumor recurrence, metastases, and short survival. Cisplatin is one of the most used chemotherapies in cancer treatment, including head and neck squamous cell carcinoma (HNSCC), and many patients develop resistance. Here, we established cell lines resistant to cisplatin to better understand epigenetics and biological differences driving the progression of HNSCC after treatment. Cisplatin resistance was established in CAL-27 and SCC-9 cell lines. Gene expression of HDAC1, HDAC2, SIRT1, MTA1, KAT2B, KAT6A, KAT6B, and BRD4 indicated the cisplatin activates the epigenetic machinery. Increases in tumor aggressiveness were detected by BMI-1 and KI-67 in more resistant cell lines. Changes in cellular shape and epithelial–mesenchymal transition (EMT) activation were also observed. HDAC1 and ZEB1 presented an opposite distribution with down-regulation of HDAC1 and up-regulation of ZEB1 in the course of chemoresistance. Up-regulation of ZEB1 and BMI-1 in patients with HNSCC is also associated with a poor response to therapy. Cancer stem cells (CSC) population increased significantly with chemoresistance. Down-regulation of HDAC1, HDAC2, and SIRT1 and accumulation of Vimentin and ZEB1 were observed in the CSC population. Our results suggest that in the route to cisplatin chemoresistance, epigenetic modifications can be associated with EMT activation and CSC accumulation which originate more aggressive tumors.     

Up-regulation of the error-prone DNA polymerase {kappa} promotes pleiotropic genetic alterations and tumorigenesis

It is currently widely accepted that genetic instability is key to cancer development. Many types of cancers arise as a consequence of a gradual accumulation of nucleotide aberrations, each mutation conferring growth and/or survival advantage. Genetic instability could also proceed in sudden bursts leading to a more drastic upheaval of structure and organization of the genome. Genetic instability, as an operative force, will produce genetic variants and the greater the instability, the larger the number of variants. We report here that the overexpression of human DNA polymerase kappa, an error-prone enzyme that is up-regulated in lung cancers, induces DNA breaks and stimulates DNA exchanges as well as aneuploidy. Probably as the result of so many perturbations, excess polymerase kappa favors the proliferation of competent tumor cells as observed in immunodeficient mice. These data suggest that altered regulation of DNA metabolism might be related to cancer-associated genetic changes and phenotype.     

In vivo effect of a resin-modified glass ionomer cement on enamel demineralization around orthodontic brackets.

Because the risk of dental caries increases with the use of orthodontic appliances and its control cannot depend only on the patient's self-care, this study evaluated the effect of a glass ionomer cement on reducing enamel demineralization around orthodontic brackets. Fourteen orthodontic patients were randomly divided into 2 groups of 7; they received 23 brackets fitted to their premolars, bonded with either Concise (3M Dental Products, St Paul, Minn), a composite resin (control group), or Fuji Ortho LC (GC America, Chicago, Ill), a resin-modified glass ionomer cement (experimental group). The volunteers lived in a city that has fluoridated water, but they did not use fluoridated dentifrices during the study. After 30 days, the teeth were extracted and longitudinally sectioned; in the enamel around the brackets, demineralization was assessed by cross-sectional microhardness. The determinations were made at the bracket edge cementing limits, and at occlusal and cervical points 100 and 200 microm away from them. In all of these positions, indentations were made at depths from 10 to 90 microm from enamel surface. Analysis of variance showed statistically significant effects for position, material, depth, and their interactions (P<.05). The Tukey test showed that the glass ionomer cement was statistically more efficient than the control, reducing enamel demineralization in all analyses (P<.05). The use of glass ionomer cement for bonding can be encouraged because it decreases the development of caries around orthodontic brackets.     

Generation of a Three-Dimensional in Vitro Ovarian Cancer Co-Culture Model for Drug Screening Assays

In vitro 3D culture models have emerged in the cancer field due to their ability to recapitulate characteristics of the in vivo tumor. Herein, we described the establishment and characterization of 3D multicellular spheroids using ovarian cancer cells (SKOV-3) in co-culture with mesenchymal cells (MUC-9) or fibroblasts (CCD27-Sk). We demonstrated that SKOV-3 cells in co-culture were able to form regular and compact spheroids with diameters ranging from 300 to 400 µm and with a roundness close to 1.0 regardless of the type of stromal cell used. In the 3D culture an increase was not observed in spheroid diameter nor was there significant cell growth. What is more, the 3D co-cultures presented an up regulation of genes related to tumorigenesis, angiogenesis and metastases (MMP2, VEGFA, SNAI1, ZEB1 and VIM) when compared with 2D and 3D monoculture. As expected, both 3D cultures (mono and co-cultures) exhibited a higher Paclitaxel chemoresistance when compared to 2D condition. Although we did not observe differences in the Paclitaxel resistance between the 3D mono and co-cultures, the gene expression results indicate that the presence of mesenchymal cells and fibroblasts better recapitulate the in vivo tumor microenvironment, being able, therefore, to more accurately evaluate drug efficacy for ovarian cancer therapy.