In vitro and in vivo performance of methacrylated gellan gum hydrogel formulations for cartilage repair

Methacrylated gellan gum (GGMA) formulation is proposed as a second‐generation hydrogel for controlled delivery of cartilage‐forming cells into focal chondral lesions, allowing immediate in situ retention of cells and 3D filling of lesion volume, such approach deemed compatible with an arthroscopic procedure. Formulation optimization was carried out in vitro using chondrocytes and adipose mesenchymal stromal/stem cells (ASCs). A proof‐of‐concept in vivo study was conducted using a rabbit model with induced chondral lesions. Outcomes were compared with microfracture or non‐treated control. Three grading scores were used to evaluate tissue repair after 8 weeks by macroscopic, histological and immunohistochemical analysis. Intense collagen type II and low collagen type I gene and protein expression were achieved in vitro by the ASC + GGMA formulation, in light with development of healthy chondral tissue. In vivo, this formulation promoted significantly superior de novo cartilage formation compared with the non‐treated group. Maintenance of chondral height and integration with native tissue was further accomplished. The physicochemical properties of the proposed GGMA hydrogel exhibited highly favorable characteristics and biological performance both in vitro and in vivo, positioning itself as an attractive xeno‐free biomaterial to be used with chondrogenic cells for a cost‐effective treatment of focal chondral lesions

To err is human, to correct is public health: a systematic review examining poor quality testing and misdiagnosis of HIV status.

INTRODUCTION: In accordance with global testing and treatment targets, many countries are seeking ways to reach the "90-90-90" goals, starting with diagnosing 90% of all people with HIV. Quality HIV testing services are needed to enable people with HIV to be diagnosed and linked to treatment as early as possible. It is essential that opportunities to reach people with undiagnosed HIV are not missed, diagnoses are correct and HIV-negative individuals are not inadvertently initiated on life-long treatment. We conducted this systematic review to assess the magnitude of misdiagnosis and to describe poor HIV testing practices using rapid diagnostic tests. METHODS: We systematically searched peer-reviewed articles, abstracts and grey literature published from 1 January 1990 to 19 April 2017. Studies were included if they used at least two rapid diagnostic tests and reported on HIV misdiagnosis, factors related to potential misdiagnosis or described quality issues and errors related to HIV testing. RESULTS: Sixty-four studies were included in this review. A small proportion of false positive (median 3.1%, interquartile range (IQR): 0.4-5.2%) and false negative (median: 0.4%, IQR: 0-3.9%) diagnoses were identified. Suboptimal testing strategies were the most common factor in studies reporting misdiagnoses, particularly false positive diagnoses due to using a "tiebreaker" test to resolve discrepant test results. A substantial proportion of false negative diagnoses were related to retesting among people on antiretroviral therapy. Conclusions HIV testing errors and poor practices, particularly those resulting in false positive or false negative diagnoses, do occur but are preventable. Efforts to accelerate HIV diagnosis and linkage to treatment should be complemented by efforts to improve the quality of HIV testing services and strengthen the quality management systems, particularly the use of validated testing algorithms and strategies, retesting people diagnosed with HIV before initiating treatment and providing clear messages to people with HIV on treatment on the risk of a "false negative" test result

A review of web-based support systems for students in higher education

Abstract Background Recent evidence suggests that there is an increasing need for accessible and anonymous services to support higher education (HE) students suffering from psychological and/or academic difficulties. Such difficulties can lead to several negative outcomes, including poor academic performance, sub-optimal mental health, reduced study satisfaction, and dropout from study. Currently, universities in the UK lack financial resources and the on-campus mental health services traditionally offered to students are increasingly economically unsustainable. Compounded by the perceived stigma of using such services, mental health providers have been driven to address the escalating needs of students through online services. Methods In this paper, we review online support systems identified through a literature search and a manual search of references in the identified papers. Further systems were identified through web searches, and systems still in development were identified by consultation with researchers in the field. We accessed systems online to extract relevant information, regarding the main difficulties addressed by the systems, the psychological techniques used and any relevant research evidence to support their effectiveness. Conclusion A large number of web-based support systems have been developed to support mental health and wellbeing, although few specifically target HE students. Further research is necessary to establish the effectiveness of such interventions in providing a cost-effective alternative to face-to-face therapy, particularly in certain settings such as HE institutions

Avaliação de efeitos tóxicos agudos e crónicos do nitrato em fases iniciais de desenvolvimento do peixe-zebra

Jobert Véronique. In memoriam Jean Breuillard. In: Revue Russe n°38, 2012. La perestroïka de Gorbatchev : piteuse déconfiture ou réussite historique ? p. 6

Assessment of Membrane Fluidity in Individual Yeast Cells by Laurdan Generalised Polarisation and Multi-photon Scanning Fluorescence Microscopy

Here we describe techniques that we developed for monitoring membrane fluidity of individual yeast cells during environmental adaptation and physiological changes. Multi-photon scanning fluorescence microscopy using laurdan as a membrane probe enables determination whether fluidity changes seen by spectroscopy reflect universal responses or changes only of sub-populations. Yeast membranes are a primary site of environmental response and adaptation. Using fluorescence spectroscopy with DPH polarization and laurdan Generalized Polarization (GP), we previously found rapid 'average' membrane fluidity modulation in yeast populations during growth and in response to nutrients or environmental stresses. To determine whether such responses reflect all cells we conducted the first multi-photon scanning fluorescence microscopy study of yeasts, measuring Laurdan GP. We assessed membrane fluidity responses of individual yeasts related to growth phase, heat stress and ethanol stress. Average fluidity decreased as cultures aged, however the decreased fluidity was due in some cases to an increasing proportion of uniformly low fluidity (high GP) cells, which were shown by vital dye to be dead. When yeasts were heat stressed, the mean Laurdan GP increased in all cells, thus the entire population evidenced damage (viz. decreased membrane fluidity) to the same degree. On the other hand, with ethanol stress fluidity increased (GP decreased) on exposure of cells. All cells were affected although not to the same degree, and with variable recovery. The recovery assessed from GP microscopy was highly variable, and greater by that seen by spectroscopy