Diffusion through the ex vivo vitreal body - bovine, porcine, and ovine models are poor surrogates for the human vitreous

© 2018 The Authors. Published by Elsevier B.V.The human vitreous humour is a complex gel structure whose composition and physical properties can vary considerably from person to person and also change with age. To date, the viscoelastic properties of the human vitreous gel has not been thoroughly investigated and despite many years of intensive research, an ideal vitreous substitute remains a challenge. Understanding the physical structure and properties of the vitreous is of fundamental and therapeutic interest, providing a clear insight into diffusion and transport of administered ophthalmic drug molecules into the vitreous. A number of mammalian surrogates, mainly bovine, porcine and ovine vitreous humours have been greatly used in the literature as a means of studying ophthalmic drug transport and diffusion. In this study, the mechanical, physical and rheological properties of ovine, porcine, and bovine surrogates were investigated and compared to human vitreous. In addition, a bespoke Franz cell construct was used to compare the diffusion of a model drug (i.e. fluorescein) through vitreous samples. Despite the similarity in rheological properties between bovine, porcine and human vitreous samples (p > 0.05), diffusion of fluorescein through the different vitreous samples revealed great differences in values of steady-state flux and diffusion coefficient. In addition, a first-generation vitreous mimic, composed of 4.5 mg/mL hyaluronic acid with complex viscosity of 0.3 ± 0.01 Pa has been evaluated and was demonstrated to be a better mimic of the human vitreous than the mammalian samples investigated.Peer reviewedFinal Published versio

Optimization of Friction Stir Welding Parameters of Al 6061 and Al 7075 Using GRA

لحام الخلط الاحتكاكي هو تكنولوجيا واعدة لربط سبائك الألومنيوم غير المتشابهة. سبائك الالمنيوم تستخدم بصورة شائعة في صناعات الفضاء مثل ابدان الطائرات والالواح والأجنحة نظرا لمتانته العالية نسبه الى وزنه. لذلك هنالك محاوله للوصول الى أمثليه متغيرات عمليه اللحام الاحتكاكي عند لحام سبيكتين من الالمنيوم هما6061 و7075 باستخدام برنامجMinitab 16  من اجل تحسين خصائص الشد مثل اجهاد الخضوع (YS) ومتانة الشد القصوى(UTS) ونسبة الاستطالة(E) . طريقه Taguchi استخدمت كأساس لتحليل العلاقة الرمادية (GRA) باستخدام عاملين هما سرعه دوران الاداة (TRS) وسرعه اللحام (WS بأربع مستويات. النتائج اظهرت ان المتغيرات التي هي سرعه دوران الاداة وسرعه اللحام لها تأثير كبير على اجهاد الخضوع ومتانة الشد القصوى ونسبة الاستطالة. كما اظهرت النتائج ان طريقه Taguchi المستخدمة كأساس لتحليل العلاقة الرمادية تحسن المخرجات لسبيكتي الالمنيوم 6061 7075 الملحومتان.Friction stir welding (FSW) is proved as a promising welding technology for joining dissimilar aluminium alloys. Aluminium alloys are used extensively within the aerospace industry for applications such as fuselage and wing skin panels due to their high strength to weight ratio. Therefore, an effort is made to optimize the process parameters of FSW using Al 6061 and Al 7075 alloys by the Minitab 16 program in order to enhance  tensile properties such as elongation (E), yield stress (YS), and ultimate tensile strength (UTS). Grey relational analysis (GRA) based on the Taguchi method is applied using two factors tool rotational speeds (TRS) and welding speed (WS) with four levels. Results show that the variables, namely the tool rotation speed and welding speed have a significant effect on yield stress, ultimate tensile strength and elongation. Results also show that the Taguchi based grey relational approach improved properties of output response of welded Al 6061 and Al 7075 aluminum alloys

Influence of surface geometry on the culture of human cell lines: a comparative study using flat, round-bottom and v-shaped 96 well plates

© 2017 Shafaie et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.In vitro cell based models have been invaluable tools for studying cell behaviour and for investigating drug disposition, toxicity and potential adverse effects of administered drugs. Within this drug discovery pipeline, the ability to assess and prioritise candidate compounds as soon as possible offers a distinct advantage. However, the ability to apply this approach to a cell culture study is limited by the need to provide an accurate, in vitro-like, microenvironment in conjunction with a low cost and high-throughput screening (HTS) methodology. Although the geometry and/or alignment of cells has been reported to have a profound influence on cell growth and differentiation, only a handful of studies have directly compared the growth of a single cell line on different shaped multiwell plates the most commonly used substrate for HTS, in vitro, studies. Herein, the impact of various surface geometries (flat, round and v-shaped 96 well plates), as well as fixed volume growth media and fixed growth surface area have been investigated on the characteristics of three commonly used human cell lines in biopharmaceutical research and development, namely ARPE-19 (retinal epithelial), A549 (alveolar epithelial) and Malme-3M (dermal fibroblastic) cells. The effect of the surface curvature on cells was characterised using a combination of a metabolic activity assay (CellTiter AQ/MTS), LDH release profiles (CytoTox ONE) and absolute cell counts (Guava ViaCount), respectively. In addition, cell differentiation and expression of specific marker proteins were determined using flow cytometry. These in vitro results confirmed that surface topography had a significant effect (p < 0.05) on cell activity and morphology. However, although specific marker proteins were expressed on day 1 and 5 of the experiment, no significant differences were seen between the different plate geometries (p < 0.05) at the later time point. Accordingly, these results highlight the impact of substrate geometry on the culture of a cell line and the influence it has on the cells' correct growth and differentiation characteristics. As such, these results provide important implications in many aspects of cell biology the development of a HTS, in vitro, cell based systems to further investigate different aspects of toxicity testing and drug delivery.Peer reviewedFinal Published versio

Attachment and spreading of ARPE-19 cells on different surface topographies and at different growth conditions.

<p>ARPE-19 cultured at 1 x 10⁴ cells per well density on flat, round and v-shaped well plates over 8 days and at fixed growth volume and fixed growth surface. Group A and B represent cells at FV and FSA respectively and images 1, 2 and 3 represent flat, round and v-shaped well plates respectively. Samples were photographed using GX CAM digital camera at X 4 magnification (100 μm = scale bar). Each images is accompanied by analysis of the cells in the dot plot display mode of forward scatter (FCS) versus side scatter (SSC) on a logarithmic scale, and the core population of the cells is surrounded by a gate.</p

Comparing cell activity, LDH release and viability of Malme-3M cells cultured on flat, round and V-shaped well plates at 10⁴ cells/well density over 5 days and at fixed growth volume and fixed growth surface area.

<p>Group A: Mitochondrial activity of Malme-3M cells cultured at 10⁴ cells/well density, A1) cell activity cultured on round and V-shaped well plates and relative to flat at FV; A2) cell activity cultured on round and V-shaped well plates and relative to flat at FSA. Group B: LDH release of Malme-3M cells cultured at 10⁴ cells/well density, B1) LDH release on round and V-shaped plates and relative to flat at FV; B2) LDH release on round and V-shaped plates and relative to flat at FSA. Group C: cell viability/ml of Malme-3M cells cultured at 10⁴ cells/well density l, C1) round and V-shaped cell viability relative to flat well plates at FV; C2) round and V-shaped cell viability relative to flat well plates at FSA. Data are represented as mean + SD of three independent repeats (n = 3). Any significant difference in results is shown as <i>p</i> ≤ 0.05*, <i>p</i> ≤ 0.01**, <i>p</i> ≤ 0.001*** and is relative to flat plates.</p

Attachment and spreading of A549 cells on different surface topographies and at different growth conditions.

<p>A549 cultured at 1 x 10⁴ cells per well density on flat, round and v-shaped well plates over 8 days and at fixed growth volume and fixed growth surface. Group A and B represent cells at FV and FSA respectively and images 1, 2 and 3 represent flat, round and v-shaped well plates respectively. Samples were photographed using GX CAM digital camera at X 4 magnification (100 μm = scale bar). Each images is accompanied by analysis of the cells in the dot plot display mode of forward scatter (FCS) versus side scatter (SSC) on a logarithmic scale, and the core population of the cells is surrounded by a gate.</p

Calculation of surface area (SA) based on 100 μl cell suspension volume (V) on flat well plates.

<p>Calculation of surface area (SA) based on 100 μl cell suspension volume (V) on flat well plates.</p

Cell specific marker expression for RPE-65, CRALBP, CD74 and HLA-A2 using flow cytometry via indirect staining.

<p>Median Fluorescent Intensity (MFI) data for cell specific marker expression of ARPE-19, A549, and Malme-3M cell lines cultured at 1 x 10⁴ cells per well density on flat, round and v-shaped well plates over 5 days and at fixed growth volume and fixed growth surface area. Samples incubated with 2 μl per well primary antibodies and labelled with goat anti-mouse IgG FITC-tagged secondary antibody (1:500). Data is representative of 3 independent repeats and is shown as mean + SD (n = 3). Group 1: Fixed volume growth condition and Group 2: Fixed surface area growth condition showing cell specific marker expression of A) RPE-65 (ARPE-19 cell line), B) CRALBP (ARPE-19 cell line), C) CD74 (A549 cell line) and D) HLA-A2 (Malme-3M cell line) marker proteins.</p

Phenotypic variability and disparities in treatment and outcomes of childhood arthritis throughout the world: an observational cohort study

Background To our knowledge, the characteristics and burden of childhood arthritis have never been studied on a worldwide basis. We aimed to investigate, with a cross-sectional study, the prevalence of disease categories, treatment methods, and disease status in patients from across different geographical areas and from countries with diverse wealth status