Flexible nanofilms coated with aligned piezoelectric microfibers preserve the contractility of cardiomyocytes

The use of engineered cardiac tissue for high-throughput drug screening/toxicology assessment remains largely unexplored. Here we propose a scaffold that mimics aspects of cardiac extracellular matrix while preserving the contractility of cardiomyocytes. The scaffold is based on a poly(caprolactone) (PCL) nanofilm with magnetic properties (MNF, standing for magnetic nanofilm) coated with a layer of piezoelectric (PIEZO) microfibers of poly(vinylidene fluoride-trifluoroethylene) (MNF+PIEZO). The nanofilm creates a flexible support for cell contraction and the aligned PIEZO microfibers deposited on top of the nanofilm creates conditions for cell alignment and electrical stimulation of the seeded cells. Our results indicate that MNF+PIEZO scaffold promotes rat and human cardiac cell attachment and alignment, maintains the ratio of cell populations overtime, promotes cell-cell communication and metabolic maturation, and preserves cardiomyocyte (CM) contractility for at least 12 days. The engineered cardiac construct showed high toxicity against doxorubicin, a cardiotoxic molecule, and responded to compounds that modulate CM contraction such as epinephrine, propranolol and heptanol.

Treatment Adherence in Psychosis: A 2 Years Follow-Up of First-Psychotic Episode Patients

Introduction

Much research on psychosis has focused on early detection and the development of effective interventions. However, the effectiveness of any intervention depends on the willingness of the patient to engage with an intervention in a sustained manner. Disengagement from treatment by patients with serious mental illness is a major concern of mental health services.

Objectives

This study aims to examine the prevalence of disengagement in a longitudinal cohort of first episode psychosis (FEP) patients.

Methods

Retrospective naturalistic 2 years follow-up study of FEP patients aged 18 to 35 admitted into the department of psychiatry of the Beatriz Angelo's hospital from 2012 to 2014. Data on socio-demographics, clinical characteristics, appointments and medication adherence and readmissions were collected.

Results

Between 2012 and 2014 were admitted 56 patients with a FEP into the department of psychiatry of the Beatriz Angelo's hospital. The great majority of the patients (67.9%) disengaged from the treatment, both appointments and medication. Of those, 13.2% did not attend any appointment, 26.3% attended between one and three appointments and 60.5% attended at least 3 appointments before disengaged. About 23% were readmitted between the 2 years follow up period, 15.4% were readmitted more than once.

Conclusions

The evidence reviewed indicates that approximately 30% of individuals with FEP disengage from services. Continuity of care is of particular importance with FEP, given evidence suggesting that long-term care can improve symptoms and functioning and reduces relapse risk.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Atomic force microscopy and graph analysis to study the P-cadherin/SFK mechanotransduction signalling in breast cancer cells

Physical forces mediated by cell-cell adhesion molecules, as cadherins, play a crucial role in preserving normal tissue architecture. Accordingly, altered cadherins' expression has been documented as a common event during cancer progression. However, in most studies, no data exist linking pro-tumorigenic signaling and variations in the mechanical balance mediated by adhesive forces. In breast cancer, P-cadherin overexpression increases in vivo tumorigenic ability, as well as in vitro cell invasion, by activating Src family kinase (SFK) signalling. However, it is not known how P-cadherin and SFK activation impact cell-cell biomechanical properties. In the present work, using atomic force microscopy (AFM) images, cell stiffness and cell-cell adhesion measurements, and undirected graph analysis based on microscopic images, we have demonstrated that P-cadherin overexpression promotes significant alterations in cell's morphology, by decreasing cellular height and increasing its area. It also affects biomechanical properties, by decreasing cell-cell adhesion and cell stiffness. Furthermore, cellular network analysis showed alterations in intercellular organization, which is associated with cell-cell adhesion dysfunction, destabilization of an E-cadherin/p120ctn membrane complex and increased cell invasion. Remarkably, inhibition of SFK signaling, using dasatinib, reverted the pathogenic P-cadherin induced effects by increasing cell's height, cell-cell adhesion and cell stiffness, and generating more compact epithelial aggregates, as quantified by intercellular network analysis. In conclusion, P-cadherin/SFK signalling induces topological, morphological and biomechanical cell-cell alterations, which are associated with more invasive breast cancer cells. These effects could be further reverted by dasatinib treatment, demonstrating the applicability of AFM and cell network diagrams for measuring the epithelial biomechanical properties and structural organization.

Bonding durability of silorane and methacrylate-based resins to enamel

AIM

Few studies compared the silorane and mechacrylate based resins bonded to enamel. The aim of this study was to evaluate the bonding durability of silorane and methacrylate-based resins to enamel.

METHODS

Twenty seven molars were divided into G1 Clearfil SE Bond/Filtek Z350; G2 Adper Easy One/Filtek Z350; and G3 P90 Adhesive System/Filtek P90 groups. Following application of adhesive systems, blocks of composites were built, samples were stored in water (24 hours/37 ºC), sectioned (0.8 mm²) and tested in tensile (24 hours and 6 months). Fractures were observed (40×). Bond strength (in MPa) was analysed by MANOVA General Linear Model and Tukey's post-hoc test at 5%. The power test was calculated. The etching pattern was observed.

RESULTS

There were differences for material (P=0.029), storage time (P=0.012) and their interaction (P=0.000). Similar bond strengths were found at 24 h for all. The bond strength of G1 decreased after 6 months. At 6 months, G2 showed higher bond strength than G1 and G3, that were similar. The power-test value was 0.87. Mixed fractures and enamel rods were observed.

CONCLUSION

Bond strength varied over time depending on the restorative system.

Prevalence of obesity among Portuguese children (6-8 years old) using three definition criteria: COSI Portugal, 2008

INTRODUCTION

Previous studies place Portugal among the five countries with the highest prevalence of childhood obesity in Europe. This paper describes the prevalence of thinness, overweight and obesity in Portuguese children of 6-8 years of age, based on the first data collection from Childhood Obesity Surveillance Initiative Portugal, which took place during the 2007/2008 school year.

METHODS

This study uses a semi-longitudinal design with repeated cross-sectional national representative samples. Specific prevalence of overweight (including obesity) and obesity was determined using three different diagnostic criteria. Across the seven geographic regions, 3765 children were enrolled from 181 schools; 50.3% of participants were males.

RESULTS

Using the International Obesity Task Force reference, the prevalence of thinness, overweight and obesity were 4.8%, 28.1% and 8.9%, respectively; using the Center for Disease Control and Prevention reference they were 2.1%, 32.2% and 14.6%, respectively; and according to the World Health Organization reference, they were 1.0%, 37.9% and 15.3%, respectively. Univariate analysis showed a higher risk of obesity in older children, in boys and in the Azores region. The islands of Madeira and the Azores were the regions with the highest prevalence of overweight at 39.4% and 46.6%, respectively, and Algarve was the one with the lowest (21.4%).

CONCLUSION

These findings demonstrate the need for urgent action in Portugal and provide policy-makers with comprehensive and detailed information to assist with this.