178 research outputs found

    PTCH-1 and MDM2 expression in ameloblastoma from a West African sub-population: Implication for chemotherapeutics

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    Introduction: Ameloblastoma is a slow growing, painless odontogenic swelling which can attain sizes that result in severe deformities of thecraniofacial complex. It is the most commonly encountered odontogenic tumor in Nigeria. Surgical intervention is currently the method of treatment; however identification of altered molecular pathways may inform  chemotherapeutic potential. The Protein Patched homolog 1 (PTCH-1)is overexpressed in ameloblastoma. Also, mutation in the MDM2 gene can reduce the tumor suppressor function of p53 and promote ameloblastoma growth. No study however has characterized the molecular profile of African cases of ameloblastoma with a view to developing chemotherapeutic alternatives. The objective was to characterize the PTCH-1 genetic profile of Ameloblastoma in Nigerian patients as a first step in investigating its potential for chemotherapeutic intervention.Methods: Twenty-eight FFPE blocks of ameloblastoma cases from Nigerian patients were prepared for antibody processing to PTCH-1 (Polyclonal  Anti-PTCH antibody ab39266) and MDM2 (Monoclonal Anti-MDM2 antibody (2A10) ab16895). Cytoplasmic brown staining was considered as positive for PTCH while nuclear staining was positive for MDM2.Results: Moderate and strong expressions for PTCH in ameloblast and stellate reticulum were 78.6% and 60.7% respectively. Only 3 (10.7%) cases expressed MDM2.Conclusion: The importance of our study is that it supports, in theory, anti-PTCH/SHH chemotherapeutics for Nigerian ameloblastoma cases andalso infers the possible additional use of anti-p53 agents

    Assessing the pathogenicity of RYR1 variants in malignant hyperthermia

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    Background: Missense variants in the ryanodine receptor 1 gene (RYR1) are associated with malignant hyperthermia but only a minority of these have met criteria for use in predictive DNA diagnosis. We examined the utility of a simplified method of segregation analysis and a functional assay for determining the pathogenicity of recurrent RYR1 variants associated with malignant hyperthermia. Methods: We identified previously uncharacterised RYR1 variants found in 4 or more malignant hyperthermia families and conducted simplified segregation analyses. An efficient cloning and mutagenesis strategy was used to express ryanodine receptor protein containing one of six RYR1 variants in HEK293 cells. Caffeine-induced calcium release, measured using a fluorescent calcium indicator, was compared in cells expressing each variant to that in cells expressing wild type ryanodine receptor protein. Results: We identified 43 malignant hyperthermia families carrying one of the six RYR1 variants. There was segregation of genotype with the malignant hyperthermia susceptibility phenotype in families carrying the p.E3104K and p.D3986E variants but the number of informative meioses limited the statistical significance of the associations. HEK293 functional assays demonstrated an increased sensitivity of RyR1 channels containing the p.R2336H, p.R2355W, p.E3104K, p.G3990V and p.V4849I compared to wild type but cells expressing p.D3986E had a similar caffeine sensitivity to cells expressing wild type RyR1. Conclusions: Segregation analysis is of limited value in assessing pathogenicity of RYR1 variants in malignant hyperthermia. Functional analyses in HEK293 cells provided evidence to support the use of p.R2336H, p.R2355W, p.E3104K, p.G3990V and p.V4849I for diagnostic purposes but not p.D3986E

    The Intentional Use of Service Recovery Strategies to Influence Consumer Emotion, Cognition and Behaviour

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    Service recovery strategies have been identified as a critical factor in the success of. service organizations. This study develops a conceptual frame work to investigate how specific service recovery strategies influence the emotional, cognitive and negative behavioural responses of . consumers., as well as how emotion and cognition influence negative behavior. Understanding the impact of specific service recovery strategies will allow service providers' to more deliberately and intentionally engage in strategies that result in positive organizational outcomes. This study was conducted using a 2 x 2 between-subjects quasi-experimental design. The results suggest that service recovery has a significant impact on emotion, cognition and negative behavior. Similarly, satisfaction, negative emotion and positive emotion all influence negative behavior but distributive justice has no effect

    CA8 Mutations Cause a Novel Syndrome Characterized by Ataxia and Mild Mental Retardation with Predisposition to Quadrupedal Gait

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    We describe a consanguineous Iraqi family in which affected siblings had mild mental retardation and congenital ataxia characterized by quadrupedal gait. Genome-wide linkage analysis identified a 5.8 Mb interval on chromosome 8q with shared homozygosity among the affected persons. Sequencing of genes contained in the interval revealed a homozygous mutation, S100P, in carbonic anhydrase related protein 8 (CA8), which is highly expressed in cerebellar Purkinje cells and influences inositol triphosphate (ITP) binding to its receptor ITPR1 on the endoplasmatic reticulum and thereby modulates calcium signaling. We demonstrate that the mutation S100P is associated with proteasome-mediated degradation, and thus presumably represents a null mutation comparable to the Ca8 mutation underlying the previously described waddles mouse, which exhibits ataxia and appendicular dystonia. CA8 thus represents the third locus that has been associated with quadrupedal gait in humans, in addition to the VLDLR locus and a locus at chromosome 17p. Our findings underline the importance of ITP-mediated signaling in cerebellar function and provide suggestive evidence that congenital ataxia paired with cerebral dysfunction may, together with unknown contextual factors during development, predispose to quadrupedal gait in humans

    Multi-exon deletions of the FBN1 gene in Marfan syndrome

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    BACKGROUND: Mutations in the fibrillin -1 gene (FBN1) cause Marfan syndrome (MFS), an autosomal dominant multi-system connective tissue disorder. The 200 different mutations reported in the 235 kb, 65 exon-containing gene include only one family with a genomic multi-exon deletion. METHODS: We used long-range RT-PCR for mutation detection and long-range genomic PCR and DNA sequencing for identification of deletion breakpoints, allele-specific transcript analyses to determine stability of the mutant RNA, and pulse-chase studies to quantitate fibrillin synthesis and extracellular matrix deposition in cultured fibroblasts. Southern blots of genomic DNA were probed with three overlapping fragments covering the FBN1 coding exons RESULTS: Two novel multi-exon FBN1 deletions were discovered. Identical nucleotide pentamers were found at or near the intronic breakpoints. In a Case with classic MFS, an in-frame deletion of exons 42 and 43 removed the C-terminal 24 amino acids of the 5(th) LTBP (8-cysteine) domain and the adjacent 25(th) calcium-binding EGF-like (6-cysteine) domain. The mutant mRNA was stable, but fibrillin synthesis and matrix deposition were significantly reduced. A Case with severe childhood-onset MFS has a de novo deletion of exons 44–46 that removed three EGF-like domains. Fibrillin protein synthesis was normal, but matrix deposition was strikingly reduced. No genomic rearrangements were detected by Southern analysis of 18 unrelated MFS samples negative for FBN1 mutation screening. CONCLUSIONS: Two novel deletion cases expand knowledge of mutational mechanisms and genotype/phenotype correlations of fibrillinopathies. Deletions or mutations affecting an LTBP domain may result in unstable mutant protein cleavage products that interfere with microfibril assembly

    GDNF and Parkinson's Disease : Where Next? A Summary from a Recent Workshop

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    The concept of repairing the brain with growth factors has been pursued for many years in a variety of neurodegenerative diseases including primarily Parkinson's disease (PD) using glial cell line-derived neurotrophic factor (GDNF). This neurotrophic factor was discovered in 1993 and shown to have selective effects on promoting survival and regeneration of certain populations of neurons including the dopaminergic nigrostriatal pathway. These observations led to a series of clinical trials in PD patients including using infusions or gene delivery of GDNF or the related growth factor, neurturin (NRTN). Initial studies, some of which were open label, suggested that this approach could be of value in PD when the agent was injected into the putamen rather than the cerebral ventricles. In subsequent double-blind, placebo-controlled trials, the most recent reporting in 2019, treatment with GDNF did not achieve its primary end point. As a result, there has been uncertainty as to whether GDNF (and by extrapolation, related GDNF family neurotrophic factors) has merit in the future treatment of PD. To critically appraise the existing work and its future, a special workshop was held to discuss and debate this issue. This paper is a summary of that meeting with recommendations on whether there is a future for this therapeutic approach and also what any future PD trial involving GDNF and other GDNF family neurotrophic factors should consider in its design.Peer reviewe

    Influence of festival attribute qualities on Slow Food tourists’ experience, satisfaction level and revisit intention

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    The purpose of this study is to examine the impact of Slow Food festival attributes on visitors’ overall experience, their satisfaction level and revisit intention. A total of 209 useable questionnaires were collected from visitors at Mold Slow Food Festival and Exploratory Factor Analysis was conducted using AMOS 19.0. A theoretical model representing the relationships among festival attribute qualities, experience quality, satisfaction level and revisit intention is examined using path analysis. With the addition of new paths from programmes to satisfaction and food and other amenities to satisfaction, a revised theoretical model emerged. It indicated that all three festival attribute qualities (programmes, food and other amenities and entertainment) have direct impacts on the visitors’ overall experience and satisfaction; however only the quality of food and other amenities contributed directly to revisit intention of the Slow Food festival

    Marketing (as) Rhetoric: paradigms, provocations, and perspectives

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    In this collection of short, invited essays on the topic of marketing (as) rhetoric we deal with a variety of issues that demonstrate the centrality of rhetoric and rhetorical considerations to the pursuit of marketing scholarship, research and practice. Stephen Brown examines the enduring rhetorical power of the 4Ps; Chris Hackley argues for the critical power of rhetorical orientations in marketing scholarship but cautions us on the need to work harder in conceptually connecting rhetorical theory and modern marketing frameworks; Shelby Hunt explains how rhetorical processes are incorporated in his inductive realist model of theory generation, using one of his most successful publications as an illustration; Charles Marsh demonstrates what Isocrates’ broad rhetorical project has to teach us about the importance of reputation cultivation in modern marketing; Nicholas O’Shaughnessy uses an analysis of Trump’s discourse to argue that political marketing as it is currently conceived is ill-equipped to engage effectively with the rhetorical force of Trump’s ‘unmarketing’; Barbara Phillips uses Vygotsky’s work on imagination to investigate the important of pleasure and play in advertising rhetoric; and finally, David Tonks, who in many ways started it all, reiterates the need for marketers to recognise the strength of the relationship between marketing and persuasion

    MicroRNAs Differentially Expressed in Postnatal Aortic Development Downregulate Elastin via 3′ UTR and Coding-Sequence Binding Sites

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    Elastin production is characteristically turned off during the maturation of elastin-rich organs such as the aorta. MicroRNAs (miRNAs) are small regulatory RNAs that down-regulate target mRNAs by binding to miRNA regulatory elements (MREs) typically located in the 3′ UTR. Here we show a striking up-regulation of miR-29 and miR-15 family miRNAs during murine aortic development with commensurate down-regulation of targets including elastin and other extracellular matrix (ECM) genes. There were a total of 14 MREs for miR-29 in the coding sequences (CDS) and 3′ UTR of elastin, which was highly significant, and up to 22 miR-29 MREs were found in the CDS of multiple ECM genes including several collagens. This overrepresentation was conserved throughout mammalian evolution. Luciferase reporter assays showed synergistic effects of miR-29 and miR-15 family miRNAs on 3′ UTR and coding-sequence elastin constructs. Our results demonstrate that multiple miR-29 and miR-15 family MREs are characteristic for some ECM genes and suggest that miR-29 and miR-15 family miRNAs are involved in the down-regulation of elastin in the adult aorta
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