Mathematical Modelling of Chemical Diffusion through Skin using Grid-based PSEs

A Problem Solving Environment (PSE) with connections to remote distributed Grid processes is developed. The Grid simulation is itself a parallel process and allows steering of individual or multiple runs of the core computation of chemical diffusion through the stratum corneum, the outer layer of the skin. The effectiveness of this Grid-based approach in improving the quality of the simulation is assessed

X-linked Angelman-like syndrome caused by Slc9a6 knockout in mice exhibits evidence of endosomal–lysosomal dysfunction

Mutations in solute carrier family 9 isoform 6 on chromosome Xq26.3 encoding sodium–hydrogen exchanger 6, a protein mainly expressed in early and recycling endosomes are known to cause a complex and slowly progressive degenerative human neurological disease. Three resulting phenotypes have so far been reported: an X-linked Angelman syndrome-like condition, Christianson syndrome and corticobasal degeneration with tau deposition, with each characterized by severe intellectual disability, epilepsy, autistic behaviour and ataxia. Hypothesizing that a sodium–hydrogen exchanger 6 deficiency would most likely disrupt the endosomal–lysosomal system of neurons, we examined Slc9a6 knockout mice with tissue staining and related techniques commonly used to study lysosomal storage disorders. As a result, we found that sodium–hydrogen exchanger 6 depletion leads to abnormal accumulation of GM2 ganglioside and unesterified cholesterol within late endosomes and lysosomes of neurons in selective brain regions, most notably the basolateral nuclei of the amygdala, the CA3 and CA4 regions and dentate gyrus of the hippocampus and some areas of cerebral cortex. In these select neuronal populations, histochemical staining for β-hexosaminidase activity, a lysosomal enzyme involved in the degradation of GM2 ganglioside, was undetectable. Neuroaxonal dystrophy similar to that observed in lysosomal disease was observed in the cerebellum and was accompanied by a marked and progressive loss of Purkinje cells, particularly in those lacking the expression of Zebrin II. On behavioural testing, Slc9a6 knockout mice displayed a discrete clinical phenotype attributable to motor hyperactivity and cerebellar dysfunction. Importantly, these findings show that sodium–hydrogen exchanger 6 loss of function in the Slc9a6-targeted mouse model leads to compromise of endosomal–lysosomal function similar to lysosomal disease and to conspicuous neuronal abnormalities in specific brain regions, which in concert could provide a unified explanation for the cellular and clinical phenotypes in humans with SLC9A6 mutations

Activation of PTHrP-cAMP-CREB1 signaling following p53 loss is essential for osteosarcoma initiation and maintenance

Mutations in the P53 pathway are a hallmark of human cancer. The identification of pathways upon which p53-deficient cells depend could reveal therapeutic targets that may spare normal cells with intact p53. In contrast to P53 point mutations in other cancer, complete loss of P53 is a frequent event in osteosarcoma (OS), the most common cancer of bone. The consequences of p53 loss for osteoblastic cells and OS development are poorly understood. Here we use murine OS models to demonstrate that elevated Pthlh (Pthrp), cAMP levels and signalling via CREB1 are characteristic of both p53-deficient osteoblasts and OS. Normal osteoblasts survive depletion of both PTHrP and CREB1. In contrast, p53-deficient osteoblasts and OS depend upon continuous activation of this pathway and undergo proliferation arrest and apoptosis in the absence of PTHrP or CREB1. Our results identify the PTHrP-cAMP-CREB1 axis as an attractive pathway for therapeutic inhibition in OS.Mannu K Walia, Patricia MW Ho, Scott Taylor, Alvin JM Ng, Ankita Gupte, Alistair M Chalk, Andrew CW Zannettino, T John Martin, Carl R Walkle

Laccase-catalyzed decolorization of the synthetic azo-dye diamond black PV 200 and of some structurally related derivatives

The kinetics of laccase-catalyzed transformation of the azo-dye Diamond Black PV 200 (CI Mordant Black 9) and various related synthesized derivatives were analyzed for dependence on pH and substrate structure. The reaction mixture of Diamond Black PV 200 was analyzed by HPLC/MS_/MS and it was shown that upon laccase oxidation, reactive chinoid fragments of lower molecular weight were formed. These may further oligomerize as indicated by the appearance of a number of compounds with increased molecular weight. The pH optimum for the decolorization was pH 5 for Diamond Black PV 200 which did not change significantly when the substitution pattern of its basic structure was varied. Biodegradability, however, was strongly dependent on the structure of the dyes

HIF-1α is required for hematopoietic stem cell mobilization and 4-prolyl hydroxylase inhibitors enhance mobilization by stabilizing HIF-1α

Many patients with hematological neoplasms fail to mobilize sufficient numbers of hematopoietic stem cells (HSCs) in response to granulocyte colony-stimulating factor (G-CSF) precluding subsequent autologous HSC transplantation. Plerixafor, a specific antagonist of the chemokine receptor CXCR4, can rescue some but not all patients who failed to mobilize with G-CSF alone. These refractory poor mobilizers cannot currently benefit from autologous transplantation. To discover alternative targetable pathways to enhance HSC mobilization, we studied the role of hypoxia-inducible factor-1α (HIF-1α) and the effect of HIF-1α pharmacological stabilization on HSC mobilization in mice. We demonstrate in mice with HSC-specific conditional deletion of the Hif1a gene that the oxygen-labile transcription factor HIF-1α is essential for HSC mobilization in response to G-CSF and Plerixafor. Conversely, pharmacological stabilization of HIF-1α with the 4-prolyl hydroxylase inhibitor FG-4497 synergizes with G-CSF and Plerixafor increasing mobilization of reconstituting HSCs 20-fold compared with G-CSF plus Plerixafor, currently the most potent mobilizing combination used in the clinic

Finite element simulation of three-dimensional free-surface flow problems

An adaptive finite element algorithm is described for the stable solution of three-dimensional free-surface-flow problems based primarily on the use of node movement. The algorithm also includes a discrete remeshing procedure which enhances its accuracy and robustness. The spatial discretisation allows an isoparametric piecewise-quadratic approximation of the domain geometry for accurate resolution of the curved free surface. The technique is illustrated through an implementation for surface-tension-dominated viscous flows modelled in terms of the Stokes equations with suitable boundary conditions on the deforming free surface. Two three-dimensional test problems are used to demonstrate the performance of the method: a liquid bridge problem and the formation of a fluid droplet

BET inhibitors induce apoptosis through a MYC independent mechanism and synergise with CDK inhibitors to kill osteosarcoma cells

Osteosarcoma (OS) survival rates have plateaued in part due to a lack of new therapeutic options. Here we demonstrate that bromodomain inhibitors (BETi), JQ1, I-BET151, I-BET762, exert potent anti-tumour activity against primary and established OS cell lines, mediated by inhibition of BRD4. Strikingly, unlike previous observations in long-term established human OS cell lines, the antiproliferative activity of JQ1 in primary OS cells was driven by the induction of apoptosis, not cell cycle arrest. In further contrast, JQ1 activity in OS was mediated independently of MYC downregulation. We identified that JQ1 suppresses the transcription factor FOSL1 by displacement of BRD4 from its locus. Loss of FOSL1 phenocopied the antiproliferative effects of JQ1, identifying FOSL1 suppression as a potential novel therapeutic approach for OS. As a monotherapy JQ1 demonstrated significant anti-tumour activity in vivo in an OS graft model. Further, combinatorial treatment approaches showed that JQ1 increased the sensitivity of OS cells to doxorubicin and induced potent synergistic activity when rationally combined with CDK inhibitors. The greater level of activity achieved with the combination of BETi with CDK inhibitors demonstrates the efficacy of this combination therapy. Taken together, our studies show that BET inhibitors are a promising new therapeutic for OS

Chronic Cyclodextrin Treatment of Murine Niemann-Pick C Disease Ameliorates Neuronal Cholesterol and Glycosphingolipid Storage and Disease Progression

BACKGROUND:Niemann-Pick type C (NPC) disease is a fatal neurodegenerative disorder caused most commonly by a defect in the NPC1 protein and characterized by widespread intracellular accumulation of unesterified cholesterol and glycosphingolipids (GSLs). While current treatment therapies are limited, a few drugs tested in Npc1(-/-) mice have shown partial benefit. During a combination treatment trial using two such compounds, N-butyldeoxynojirimycin (NB-DNJ) and allopregnanolone, we noted increased lifespan for Npc1(-/-) mice receiving only 2-hydroxypropyl-beta-cyclodextrin (CD), the vehicle for allopregnanolone. This finding suggested that administration of CD alone, but with greater frequency, might provide additional benefit. METHODOLOGY/PRINCIPAL FINDINGS:Administration of CD to Npc1(-/-) mice beginning at either P7 or P21 and continuing every other day delayed clinical onset, reduced intraneuronal cholesterol and GSL storage as well as free sphingosine accumulation, reduced markers of neurodegeneration, and led to longer survival than any previous treatment regime. We reasoned that other lysosomal diseases characterized by cholesterol and GSL accumulation, including NPC disease due to NPC2 deficiency, GM1 gangliosidosis and mucopolysaccharidosis (MPS) type IIIA, might likewise benefit from CD treatment. Treated Npc2(-/-) mice showed benefits similar to NPC1 disease, however, mice with GM1 gangliosidosis or MPS IIIA failed to show reduction in storage. CONCLUSIONS/SIGNIFICANCE:Treatment with CD delayed clinical disease onset, reduced intraneuronal storage and secondary markers of neurodegeneration, and significantly increased lifespan of both Npc1(-/-) and Npc2(-/-) mice. In contrast, CD failed to ameliorate cholesterol or glycosphingolipid storage in GM1 gangliosidosis and MPS IIIA disease. Understanding the mechanism(s) by which CD leads to reduced neuronal storage may provide important new opportunities for treatment of NPC and related neurodegenerative diseases characterized by cholesterol dyshomeostasis

Effects of Expert Testimony and Interrogation Tactics on Perceptions of Confessions

Evidence obtained through the process of interrogation is frequently undermined by what can be perceived as overzealous interrogation tactics. Although the majority of psychologically oriented tactics are legally permissible, they nonetheless contribute to innocent suspects confessing to crimes they did not commit. The present study examined the effect of expert testimony and interrogation tactics on perceptions of a confession. 182 undergraduates read a transcript of a homicide trial that varied based on interrogation tactic: implicit threat of punishment (maximization) or leniency (minimization) and expert witness testimony (presence or absence of expert testimony). Analysis indicated that the type of interrogation tactic used in obtaining the confession affected participants\u27 perceptions of the coerciveness of the interrogation process