159 research outputs found

    The Effect of Student-Driven Projects on the Development of Statistical Reasoning

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    Research has shown that even if students pass a standard introductory statistics course, they often still lack the ability to reason statistically. Many instructional techniques for enhancing the development of statistical reasoning have been discussed by several authors,although, there is often little to no quantitative analysis to give evidence that they produce effective results in the classroom.The purpose of this study was to produce quantitative data to investigate the effectivenessof a particular teaching technique in enhancing students' statistical reasoning abilities. Thestudy compared students in a traditional lecture-based introductory statistics course withstudents in a similar introductory course that adds a semester-long project. The projectwas designed to target three main focus areas found in an introductory statistics course:distributions, probability and inference. Seven sections of introductory statistics courseswere used. One section at each level served as an experimental section and used a five part project in the course curriculum. All other sections followed a typical introductory curriculum for the specific course level.All sections involved completed both a pre-test and a post-test. Both assessments were designed to measure reasoning ability targeted by the project in order to determine if using the project aids in the increased development of statistical reasoning.Additional purposes of this research were to develop assessment questions that targetstudents' reasoning abilities and to provide a template for a semester-long data analysisproject for introductory courses.Analysis of the data was completed using methods that included ANCOVA and contingency tables to investigate the effect of the project on the development of students' statistical reasoning. A qualitative analysis is also discussed to provide information on aspects of the project not covered by the quantitative analysis.Analysis of the data indicated that project participants had higher learning gains overallwhen compared with the gains made by students not participating in the project. Results of the qualitative analysis also suggest that, in addition to providing larger learning gains,projects were also enjoyed by students. These results indicate that the use of projects are avaluable teaching technique for introductory statistics courses

    A Pilot Study Investigating the Effect of the Supervision-Questioning-Feedback Model of Supervision on Stimulating Critical Thinking in Speech-Language Pathology Graduate Students

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    Purpose The purpose of this study was to investigate the effect of the supervision-questioning-feedback (SQF) model of supervision on critical thinking in graduate students studying speech-language pathology. The researchers hypothesized that students who were provided with the SQF model of supervision would score higher than students who received the non-SQF (NSQF) style of supervision on the selected critical thinking measures. Method Seventeen out of 24 first semester graduate students in speech-language pathology completing their on-site university-based clinical practicum experience consented to participate in the study. Of the 17 participating first semester students, 9 were randomly assigned to 1 of 3 SQF trained supervisors, and the other 8 were randomly assigned to 1 of 2 NSQF trained supervisors for the duration of 1 semester. Additionally, 3 out of 24 fourth semester graduate students completing their off-site externship experience and their supervisors consented to participate in the study. Four additional study participants served as independent SQF-trained raters charged with the task of analyzing video recorded student-supervisor conferences to determine whether the SQF model of supervision was being implemented. Prior to and at the conclusion of the clinical experience, all participating students completed two measures of critical thinking: (1) California Critical Thinking Skills Test (CCTST) and (2) two Simucase® clinical simulations. At the conclusion of the clinical experience, seventeen out of 20 participating students (11/12 SQF students and 6/8 NSQF students) completed a post-survey rating their supervisory experience . Results For participating first semester students, there were no overall statistically significant differences between SQF and NSQF groups as measured by pre to post completion of (1) CCTST (p=.544) and (2) two Simucase® clinical simulations (p=.781). The 3 participating fourth semester students who received the SQF model of supervision also showed no statistically significant differences on pre to post completion of the (1) CCTST (p=.827) and (2) two Simucase® virtual cases (p=.879). Results from SQF ratings revealed variability in the implementation of the SQF model across supervisors with a moderate level of inter-rater agreement. Results from post surveys completed by students showed that students preferred the SQF model of supervision over the NSQF model (p=.044). Conclusion Results from this preliminary study indicated that the SQF model did not influence the overall outcomes on the selected critical thinking measures. Student preference for the SQF model may support existing evidence that learning clinicians want to be actively engaged in the supervisory process. There were several limitations to this study including the small sample size, variability in the implementation of the SQF model across supervisors, sensitivity of the selected critical thinking measures, and timing of post-intervention procedures. Further investigation of the effects of SQF on students’ critical thinking is warranted

    NF-κB, stem cells and breast cancer: the links get stronger

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    Self-renewing breast cancer stem cells are key actors in perpetuating tumour existence and in treatment resistance and relapse. The molecular pathways required for their maintenance are starting to be elucidated. Among them is the transcription factor NF-κB, which is known to play critical roles in cell survival, inflammation and immunity. Recent studies indicate that mammary epithelial NF-κB regulates the self-renewal of breast cancer stem cells in a model of Her2-dependent tumourigenesis. We will describe here the NF-κB-activating pathways that are involved in this process and in which progenitor cells this transcription factor is actually activated

    Investigation into the controversial association of Streptococcus gallolyticus with colorectal cancer and adenoma

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    Background: The seroprevalence of IgG antibodies of Streptococcus gallolyticus subspecies gallolyticus, CIP 105428, was evaluated to investigate the controversial association of S. gallolyticus with colorectal carcinoma and adenoma in attempt to investigate the nature of such association if any, by exploring the mRNA expression of NF-κB and IL-8. Moreover, the serological behavior of S. gallolyticus IgG antibodies was compared to that of an indicator bacterium of bowel, Bacteroides fragilis. Methods: ELISA was used to measure IgG antibodies of S. gallolyticus and B. fragilis in sera of 50 colorectal cancer, 14 colorectal adenoma patients, 30 age- and sex- matched apparently healthy volunteers (HV) and 30 age- and sex- matched colonoscopically-proven tumor-free control subjects. NF-κB and IL-8 mRNA expression was evaluated in tumorous and non-tumorous tissue sections of carcinoma and adenoma patients in comparison with that of control subjects by using in situ hybridization assay. Results: Colorectal cancer and adenoma patients were associated with higher levels of serum S. Gallolyticus IgG antibodies in comparison with HV and control subjects (P 0.05). ELISA cutoff value for the seropositivity of S. gallolyticus IgG was calculated from tumor-free control group. The expression of NF-κB mRNA was higher in tumorous than non-tumorous tissue sections of adenoma and carcinoma, higher in carcinoma/adenoma sections than in control subjects, higher in tumorous sections of carcinoma than in adenoma patients, and higher in S. gallolyticus IgG seropositive than in seronegative groups in both tumorous and non-tumorous sections (P < 0.05). IL-8 mRNA expression in tumorous sections of adenoma and carcinoma was higher than in non-tumorous sections, higher in carcinoma/adenoma than in control subjects, and higher in S. gallolyticus IgG seropositive than in seronegative groups in tumorous rather than non-tumorous sections (P < 0.05). Conclusion: S. gallolyticus most likely plays an essential role in the oncogenic progression of normal colorectal mucosa to adenoma and to CRC. This promoting/propagating role of S. gallolyticus might take place by utilizing certain inflammatory, anti-apoptotic, and angiogenic factors of transformation including NF-κB and IL-8.Ahmed S Abdulamir, Rand R Hafidh, Layla K Mahdi, Tarik Al-jeboori and Fatimah Abubake

    Chaperones rescue the energetic landscape of mutant CFTR at single molecule and in cell

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    Molecular chaperones are pivotal in folding and degradation of the cellular proteome but their impact on the conformational dynamics of near-native membrane proteins with disease relevance remains unknown. Here we report the effect of chaperone activity on the functional conformation of the temperature-sensitive mutant cystic fibrosis channel (Delta F508-CFTR) at the plasma membrane and after reconstitution into phospholipid bilayer. Thermally induced unfolding at 37 degrees C and concomitant functional inactivation of Delta F508-CFTR are partially suppressed by constitutive activity of Hsc70 and Hsp90 chaperone/co-chaperone at the plasma membrane and post-endoplasmic reticulum compartments in vivo, and at singlemolecule level in vitro, indicated by kinetic and thermodynamic remodeling of the mutant gating energetics toward its wild-type counterpart. Thus, molecular chaperones can contribute to functional maintenance of Delta F508-CFTR by reshaping the conformational energetics of its final fold, a mechanism with implication in the regulation of metastable ABC transporters and other plasma membrane proteins activity in health and diseases

    Withanolides-Induced Breast Cancer Cell Death Is Correlated with Their Ability to Inhibit Heat Protein 90

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    Withanolides are a large group of steroidal lactones found in Solanaceae plants that exhibit potential anticancer activities. We have previously demonstrated that a withanolide, tubocapsenolide A, induced cycle arrest and apoptosis in human breast cancer cells, which was associated with the inhibition of heat shock protein 90 (Hsp90). To investigate whether other withanolides are also capable of inhibiting Hsp90 and to analyze the structure-activity relationships, nine withanolides with different structural properties were tested in human breast cancer cells MDA-MB-231 and MCF-7 in the present study. Our data show that the 2,3-unsaturated double bond-containing withanolides inhibited Hsp90 function, as evidenced by selective depletion of Hsp90 client proteins and induction of Hsp70. The inhibitory effect of the withanolides on Hsp90 chaperone activity was further confirmed using in vivo heat shock luciferase activity recovery assays. Importantly, Hsp90 inhibition by the withanolides was correlated with their ability to induce cancer cell death. In addition, the withanolides reduced constitutive NF-κB activation by depleting IκB kinase complex (IKK) through inhibition of Hsp90. In estrogen receptor (ER)-positive MCF-7 cells, the withanolides also reduced the expression of ER, and this may be partly due to Hsp90 inhibition. Taken together, our results suggest that Hsp90 inhibition is a general feature of cytotoxic withanolides and plays an important role in their anticancer activity

    Transcriptional Activation of TINF2, a Gene Encoding the Telomere-Associated Protein TIN2, by Sp1 and NF-κB Factors

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    The expression of the telomere-associated protein TIN2 has been shown to be essential for early embryonic development in mice and for development of a variety of human malignancies. Recently, germ-line mutations in TINF2, which encodes for the TIN2 protein, have been identified in a number of patients with bone-marrow failure syndromes. Yet, the molecular mechanisms that regulate TINF2 expression are largely unknown. To elucidate the mechanisms involved in human TINF2 regulation, we cloned a 2.7 kb genomic DNA fragment containing the putative promoter region and, through deletion analysis, identified a 406 bp region that functions as a minimal promoter. This promoter proximal region is predicted to contain several putative Sp1 and NF-κB binding sites based on bioinformatic analysis. Direct binding of the Sp1 and NF-κB transcription factors to the TIN2 promoter sequence was demonstrated by electrophoretic mobility shift assay (EMSA) and/or chromatin immunoprecipitation (ChIP) assays. Transfection of a plasmid carrying the Sp1 transcription factor into Sp-deficient SL2 cells strongly activated TIN2 promoter-driven luciferase reporter expression. Similarly, the NF-κB molecules p50 and p65 were found to strongly activate luciferase expression in NF-κB knockout MEFs. Mutating the predicted transcription factor binding sites effectively reduced TIN2 promoter activity. Various known chemical inhibitors of Sp1 and NF-κB could also strongly inhibit TIN2 transcriptional activity. Collectively, our results demonstrate the important roles that Sp1 and NF-κB play in regulating the expression of the human telomere-binding protein TIN2, which can shed important light on its possible role in causing various forms of human diseases and cancers

    Similar NF-κB Gene Signatures in TNF-α Treated Human Endothelial Cells and Breast Tumor Biopsies

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    BACKGROUND: Endothelial dysfunction has been implicated in the pathogenesis of diverse pathologies ranging from vascular and immune diseases to cancer. TNF-α is one of the mediators of endothelial dysfunction through the activation of transcription factors, including NF-κB. While HUVEC (macrovascular cells) have been largely used in the past, here, we documented an NF-κB gene signature in TNFα-stimulated microvascular endothelial cells HMEC often used in tumor angiogenesis studies. METHODOLOGY/PRINCIPAL FINDINGS: We measured mRNA expression of 55 NF-κB related genes using quantitative RT-PCR in HUVEC and HMEC. Our study identified twenty genes markedly up-regulated in response to TNFα, including adhesion molecules, cytokines, chemokines, and apoptosis regulators, some of them being identified as TNF-α-inducible genes for the first time in endothelial cells (two apoptosis regulators, TNFAIP3 and TNFRSF10B/Trail R2 (DR5), the chemokines GM-CSF/CSF2 and MCF/CSF1, and CD40 and TNF-α itself, as well as NF-κB components (RELB, NFKB1 or 50/p105 and NFKB2 or p52/p100). For eight genes, the fold induction was much higher in HMEC, as compared to HUVEC. Most importantly, our study described for the first time a connection between NF-κB activation and the induction of most, if not all, of these genes in HMEC as evaluated by pharmacological inhibition and RelA expression knock-down by RNA interference. Moreover, since TNF-α is highly expressed in tumors, we further applied the NF-κB gene signature documented in TNFα-stimulated endothelial cells to human breast tumors. We found a significant positive correlation between TNF and the majority (85 %) of the identified endothelial TNF-induced genes in a well-defined series of 96 (48 ERα positive and 48 ERα negative) breast tumors. CONCLUSION/SIGNIFICANCE: Taken together these data suggest the potential use of this NF-κB gene signature in analyzing the role of TNF-α in the endothelial dysfunction, as well as in breast tumors independently of the presence of ERα

    Protein-based identification of quantitative trait loci associated with malignant transformation in two HER2+ cellular models of breast cancer

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    Background A contemporary view of the cancer genome reveals extensive rearrangement compared to normal cells. Yet how these genetic alterations translate into specific proteomic changes that underpin acquiring the hallmarks of cancer remains unresolved. The objectives of this study were to quantify alterations in protein expression in two HER2+ cellular models of breast cancer and to infer differentially regulated signaling pathways in these models associated with the hallmarks of cancer. Results A proteomic workflow was used to identify proteins in two HER2 positive tumorigenic cell lines (BT474 and SKBR3) that were differentially expressed relative to a normal human mammary epithelial cell line (184A1). A total of 64 (BT474-184A1) and 69 (SKBR3-184A1) proteins were uniquely identified that were differentially expressed by at least 1.5-fold. Pathway inference tools were used to interpret these proteins in terms of functionally enriched pathways in the tumor cell lines. We observed protein ubiquitination and apoptosis signaling pathways were both enriched in the two breast cancer models while IGF signaling and cell motility pathways were enriched in BT474 and amino acid metabolism were enriched in the SKBR3 cell line. Conclusion While protein ubiquitination and apoptosis signaling pathways were common to both the cell lines, the observed patterns of protein expression suggest that the evasion of apoptosis in each tumorigenic cell line occurs via different mechanisms. Evidently, apoptosis is regulated in BT474 via down regulation of Bid and in SKBR3 via up regulation of Calpain-11 as compared to 184A1
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