Teaching complex skills in a PSI psychology course

The Personalized System of Instruction (PSI) is designed to individualize instruction based on traditional learning theories. Students are required to demonstrate mastery before advancing to new material. A self-pacing feature allows students to dictate their rate of progress. Compared to lecture-discussion instruction, PSI courses have demonstrated superior examination performance as well as increased ratings of course quality. However, studies have been criticized for testing only basic skills while ignoring more complex processes. In this research project, the PSI study guides were designed to emphasize complex processes and mastery test and review examination questions reflected increased item-level complexity. Results showed that students were able to master these complex items at the required 90% criterion. Performance on the comprehensive review examinations was slightly lower for complex items. Expected differences relating to the three group sequence requirements were not obtained. Nevertheless, mastery performance on the complex items was achieved by all students regardless of experimental group

A potential role for Dkk-1 in the pathogenesis of osteosarcoma predicts novel diagnostic and treatment strategies.

Canonical Wnt signaling is an osteo-inductive signal that promotes bone repair through acceleration of osteogenic differentiation by progenitors. Dkk-1 is a secreted inhibitor of canonical Wnt signaling and thus inhibits osteogenesis. To examine a potential osteo-inhibitory role of Dkk-1 in osteosarcoma (OS), we measured serum Dkk-1 in pediatric patients with OS (median age, 13.4 years) and found it to be significantly elevated. We also found that Dkk-1 was maximally expressed by the OS cells at the tumor periphery and _in vitro_ Dkk-1 and RANKL are co-expressed by rapidly proliferating OS cells. Both Dkk-1 and conditioned media from OS cells reduces osteogenesis by human mesenchymal cells and by immuno-depletion of Dkk-1, or by adding a GSK3[beta] inhibitor, the effects of Dkk-1 were attenuated. In mice, we found that the expression of Dkk-1 from implanted tumors was similar to the human tumor biopsies in that human Dkk-1 was present in the serum of recipient animals. These data demonstrate that systemic levels of Dkk-1 are elevated in osteosarcoma. Furthermore, the expression of Dkk-1 by the OS cells at the periphery of the tumor probably contributes to its expansion by inhibiting repair of the surrounding bone. These data demonstrate that Dkk-1 may serve as a prognostic or diagnostic marker for evaluation of OS and furthermore, immuno-depletion of Dkk-1 or administration of GSK3[beta] inhibitors could represent an adjunct therapy for this disease

Simplified production and concentration of HIV-1-based lentiviral vectors using HYPERFlask vessels and anion exchange membrane chromatography

<p>Abstract</p> <p>Background</p> <p>During the past twelve years, lentiviral (LV) vectors have emerged as valuable tools for transgene delivery because of their ability to transduce nondividing cells and their capacity to sustain long-term transgene expression in target cells <it>in vitro </it>and <it>in vivo</it>. However, despite significant progress, the production and concentration of high-titer, high-quality LV vector stocks is still cumbersome and costly.</p> <p>Methods</p> <p>Here we present a simplified protocol for LV vector production on a laboratory scale using HYPERFlask vessels. HYPERFlask vessels are high-yield, high-performance flasks that utilize a multilayered gas permeable growth surface for efficient gas exchange, allowing convenient production of high-titer LV vectors. For subsequent concentration of LV vector stocks produced in this way, we describe a facile protocol involving Mustang Q anion exchange membrane chromatography.</p> <p>Results</p> <p>Our results show that unconcentrated LV vector stocks with titers in excess of 10⁸transduction units (TU) per ml were obtained using HYPERFlasks and that these titers were higher than those produced in parallel using regular 150-cm²tissue culture dishes. We also show that up to 500 ml of an unconcentrated LV vector stock prepared using a HYPERFlask vessel could be concentrated using a single Mustang Q Acrodisc with a membrane volume of 0.18 ml. Up to 5.3 × 10¹⁰TU were recovered from a single HYPERFlask vessel.</p> <p>Conclusion</p> <p>The protocol described here is easy to implement and should facilitate high-titer LV vector production for preclinical studies in animal models without the need for multiple tissue culture dishes and ultracentrifugation-based concentration protocols.</p

A doxycycline-inducible urokinase receptor (uPAR) upregulates uPAR activities including resistance to anoikis in human prostate cancer cell lines

<p>Abstract</p> <p>Background</p> <p>The urokinase receptor (uPAR) mediates a diverse array of cellular processes including several events involved in prostate cancer metastasis. Many of these activities are initiated or enhanced by uPAR binding to its proteolytic ligand, urokinase (uPA). Our objective in this study was to generate and test an inducible lentiviral system capable of expressing uPAR and DsRed fluorescent protein in human prostate cancer cell lines.</p> <p>Results</p> <p>A DsRed-uPAR fusion construct was inserted into a lentiviral vector. Transduction of human prostate cancer cell lines with this virus and with a virus containing a reverse-tetracycline transactivator (rt-TA) resulted in a stable transgene which induced both uPAR and DsRed proteins in a dose-responsive fashion upon stimulation with doxycycline. Immunoblots and immunofluorescence studies indicated no detectable uPAR expression in non-induced prostate cancer cell lines. Cells with induced-uPAR demonstrated increased cellular adhesion to the matrix substrate vitronectin and increased net cell proliferation compared to uninduced cells. Finally, induced uPAR-expressing prostate cancer cells were resistant to anoikis over an extended time period when grown in suspension.</p> <p>Conclusion</p> <p>This doxycycline-inducible lentivirus system produces titerable levels of biologically active uPAR <it>in vitro</it>. This tool can be used to dissect cellular events following induction of uPAR in prostate cancer cells.</p

Lentiviral vectors encoding tetracycline-dependent repressors and transactivators for reversible knockdown of gene expression: a comparative study

<p>Abstract</p> <p>Background</p> <p>RNA interference (RNAi)-mediated by the expression of short hairpin RNAs (shRNAs) has emerged as a powerful experimental tool for reverse genetic studies in mammalian cells. A number of recent reports have described approaches allowing regulated production of shRNAs based on modified RNA polymerase II (Pol II) or RNA polymerase III (Pol III) promoters, controlled by drug-responsive transactivators or repressors such as tetracycline (Tet)-dependent transactivators and repressors. However, the usefulness of these approaches is often times limited, caused by inefficient delivery and/or expression of shRNA-encoding sequences in target cells and/or poor design of shRNAs sequences. With a view toward optimizing Tet-regulated shRNA expression in mammalian cells, we compared the capacity of a variety of hybrid Pol III promoters to express short shRNAs in target cells following lentivirus-mediated delivery of shRNA-encoding cassettes.</p> <p>Results</p> <p>RNAi-mediated knockdown of gene expression in target cells, controlled by a modified Tet-repressor (TetR) in the presence of doxycycline (Dox) was robust. Expression of shRNAs from engineered human U6 (hU6) promoters containing a single tetracycline operator (TO) sequence between the proximal sequence element (PSE) and the TATA box, or an improved second-generation Tet-responsive promoter element (TRE) placed upstream of the promoter was tight and reversible as judged using quantitative protein measurements. We also established and tested a novel hU6 promoter system in which the distal sequence element (DSE) of the hU6 promoter was replaced with a second-generation TRE. In this system, positive regulation of shRNA production is mediated by novel Tet-dependent transactivators bearing transactivation domains derived from the human Sp1 transcription factor.</p> <p>Conclusion</p> <p>Our modified lentiviral vector system resulted in tight and reversible knockdown of target gene expression in unsorted cell populations. Tightly regulated target gene knockdown was observed with vectors containing either a single TO sequence or a second-generation TRE using carefully controlled transduction conditions. We expect these vectors to ultimately find applications for tight and reversible RNAi in mammalian cells in vivo.</p

Cell-specific targeting of lentiviral vectors mediated by fusion proteins derived from Sindbis virus, vesicular stomatitis virus, or avian sarcoma/leukosis virus

<p>Abstract</p> <p>Background</p> <p>The ability to efficiently and selectively target gene delivery vectors to specific cell types <it>in vitro </it>and <it>in vivo </it>remains one of the formidable challenges in gene therapy. We pursued two different strategies to target lentiviral vector delivery to specific cell types. In one of the strategies, vector particles bearing a membrane-bound stem cell factor sequence plus a separate fusion protein based either on Sindbis virus strain TR339 glycoproteins or the vesicular stomatitis virus G glycoprotein were used to selectively transduce cells expressing the corresponding stem cell factor receptor (c-kit). An alternative approach involved soluble avian sarcoma/leukosis virus receptors fused to cell-specific ligands including stem cell factor and erythropoietin for targeting lentiviral vectors pseudotyped with avian sarcoma/leukosis virus envelope proteins to cells that express the corresponding receptors.</p> <p>Results</p> <p>The titers of unconcentrated vector particles bearing Sindbis virus strain TR339 or vesicular stomatitis virus G fusion proteins plus stem cell factor in the context of c-kit expressing cells were up to 3.2 × 10⁵transducing units per ml while vector particles lacking the stem cell factor ligand displayed titers that were approximately 80 fold lower. On cells that lacked the c-kit receptor, the titers of stem cell factor-containing vectors were approximately 40 times lower compared to c-kit-expressing cells.</p> <p>Lentiviral vectors pseudotyped with avian sarcoma/leukosis virus subgroup A or B envelope proteins and bearing bi-functional bridge proteins encoding erythropoietin or stem cell factor fused to the soluble extracellular domains of the avian sarcoma/leukosis virus subgroup A or B receptors resulted in efficient transduction of erythropoietin receptor or c-kit-expressing cells. Transduction of erythropoietin receptor-expressing cells mediated by bi-functional bridge proteins was found to be dependent on the dose, the correct subgroup-specific virus receptor and the correct envelope protein. Furthermore, transduction was completely abolished in the presence of anti-erythropoietin antibody.</p> <p>Conclusions</p> <p>Our results indicate that the avian sarcoma/leukosis virus bridge strategy provides a reliable approach for cell-specific lentiviral vector targeting. The background levels were lower compared to alternative strategies involving Sindbis virus strain TR339 or vesicular stomatitis virus fusion proteins.</p

Prognostic predictors relevant to end-of-life palliative care in Parkinson's disease and related disorders: A systematic review

Parkinson's disease and related disorders (PDRD) are the second most common neurodegenerative disease and a leading cause of death. However, patients with PDRD receive less end-of-life palliative care (hospice) than other illnesses, including other neurologic illnesses. Identification of predictors of PDRD mortality may aid in increasing appropriate and timely referrals. To systematically review the literature for causes of death and predictors of mortality in PDRD to provide guidance regarding hospice/end-of-life palliative care referrals. We searched MEDLINE, PubMed, EMBASE and CINAHL databases (1970-2020) of original quantitative research using patient-level, provider-level or caregiver-level data from medical records, administrative data or survey responses associated with mortality, prognosis or cause of death in PDRD. Findings were reviewed by an International Working Group on PD and Palliative Care supported by the Parkinson's Foundation. Of 1183 research articles, 42 studies met our inclusion criteria. We found four main domains of factors associated with mortality in PDRD: (1) demographic and clinical markers (age, sex, body mass index and comorbid illnesses), (2) motor dysfunction and global disability, (3) falls and infections and (4) non-motor symptoms. We provide suggestions for consideration of timing of hospice/end-of-life palliative care referrals. Several clinical features of advancing disease may be useful in triggering end-of-life palliative/hospice referral. Prognostic studies focused on identifying when people with PDRD are nearing their final months of life are limited. There is further need for research in this area as well as policies that support need-based palliative care for the duration of PDRD

A season long investigation into the effects of injury, match selection and training load on mental wellbeing in professional under 23 soccer players: A team case study

This study examined the influence of injury, match selection and training load on mental wellbeing (MW) in a squad of professional soccer players. Using a longitudinal design, twenty-five male soccer players (age, 20 ± 1 years, height, 1.80 ± 5.79 m, body mass 76.33 ± 7.52 kg) from the under 23 squad playing in the Premier League 2 division in the UK completed the Warwick–Edinburgh Mental Well-being Scale (WEMWBS) each week of the 2017/2018 season (37 weeks in total). Injury and non-selection for the match squad were the only significant predictors of MW (P  0.05). These findings highlight the importance of monitoring MW in professional soccer players and suggest that injured players and those rarely selected for the match squad should be educated on the strategies available for managing their mental health and wellbeing

Centerscope

Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.