Leaky ribosomal scanning in mammalian genomes: significance of histone H4 alternative translation in vivo

Like alternative splicing, leaky ribosomal scanning (LRS), which occurs at suboptimal translational initiation codons, increases the physiological flexibility of the genome by allowing alternative translation. Comprehensive analysis of 22 208 human mRNAs indicates that, although the most important positions relative to the first nucleotide of the initiation codon, −3 and +4, are usually such that support initiation (A(−3) = 42%, G(−3) = 36% and G(+4) = 47%), only 37.4% of the genes adhere to the purine (R)(−3)/G(+4) rule at both positions simultaneously, suggesting that LRS may occur in some of the remaining (62.6%) genes. Moreover, 12.5% of the genes lack both R(−3) and G(+4), potentially leading to sLRS. Compared with 11 genes known to undergo LRS, 10 genes with experimental evidence for high fidelity A(+1)T(+2)G(+3) initiation codons adhered much more strongly to the R(−3)/G(+4) rule. Among the intron-less histone genes, only the H3 genes adhere to the R(−3)/G(+4) rule, while the H1, H2A, H2B and H4 genes usually lack either R(−3) or G(+4). To address in vivo the significance of the previously described LRS of H4 mRNAs, which results in alternative translation of the osteogenic growth peptide, transgenic mice were engineered that ubiquitously and constitutively express a mutant H4 mRNA with an A(+1)→T(+1) mutation. These transgenic mice, in particular the females, have a high bone mass phenotype, attributable to increased bone formation. These data suggest that many genes may fulfill cryptic functions by LRS

Harmonising evidence-based medicine teaching: a study of the outcomes of e-learning in five European countries

BACKGROUND: We developed and evaluated the outcomes of an e-learning course for evidence based medicine (EBM) training in postgraduate medical education in different languages and settings across five European countries. METHODS: We measured changes in knowledge and attitudes with well-developed assessment tools before and after administration of the course. The course consisted of five e-learning modules covering acquisition (formulating a question and search of the literature), appraisal, application and implementation of findings from systematic reviews of therapeutic interventions, each with interactive audio-visual learning materials of 15 to 20 minutes duration. The modules were prepared in English, Spanish, German and Hungarian. The course was delivered to 101 students from different specialties in Germany (psychiatrists), Hungary (mixture of specialties), Spain (general medical practitioners), Switzerland (obstetricians-gynaecologists) and the UK (obstetricians-gynaecologists). We analysed changes in scores across modules and countries. RESULTS: On average across all countries, knowledge scores significantly improved from pre- to post-course for all five modules (p < 0.001). The improvements in scores were on average 1.87 points (14% of total score) for module 1, 1.81 points (26% of total score) for module 2, 1.9 points (11% of total score) for module 3, 1.9 points (12% of total score) for module 4 and 1.14 points (14% of total score) for module 5. In the country specific analysis, knowledge gain was not significant for module 4 in Spain, Switzerland and the UK, for module 3 in Spain and Switzerland and for module 2 in Spain. Compared to pre-course assessment, after completing the course participants felt more confident that they can assess research evidence and that the healthcare system in their country should have its own programme of research about clinical effectiveness. CONCLUSION: E-learning in EBM can be harmonised for effective teaching and learning in different languages, educational settings and clinical specialties, paving the way for development of an international e-EBM course

Leaky ribosomal scanning in mammalian genomes: significance of histone H4 alternative translation in vivo

Like alternative splicing, leaky ribosomal scanning (LRS), which occurs at suboptimal translational initiation codons, increases the physiological flexibility of the genome by allowing alternative translation. Comprehensive analysis of 22 208 human mRNAs indicates that, although the most important positions relative to the first nucleotide of the initiation codon, −3 and +4, are usually such that support initiation (A−3 = 42%, G−3 = 36% and G+4 = 47%), only 37.4% of the genes adhere to the purine (R)−3/G+4 rule at both positions simultaneously, suggesting that LRS may occur in some of the remaining (62.6%) genes. Moreover, 12.5% of the genes lack both R−3 and G+4, potentially leading to sLRS. Compared with 11 genes known to undergo LRS, 10 genes with experimental evidence for high fidelity A+1T+2G+3 initiation codons adhered much more strongly to the R−3/G+4 rule. Among the intron-less histone genes, only the H3 genes adhere to the R−3/G+4 rule, while the H1, H2A, H2B and H4 genes usually lack either R−3 or G+4. To address in vivo the significance of the previously described LRS of H4 mRNAs, which results in alternative translation of the osteogenic growth peptide, transgenic mice were engineered that ubiquitously and constitutively express a mutant H4 mRNA with an A+1→T+1 mutation. These transgenic mice, in particular the females, have a high bone mass phenotype, attributable to increased bone formation. These data suggest that many genes may fulfill cryptic functions by LR

How are "teaching the teachers" courses in evidence based medicine evaluated? A systematic review

Background Teaching of evidence-based medicine (EBM) has become widespread in medical education. Teaching the teachers (TTT) courses address the increased teaching demand and the need to improve effectiveness of EBM teaching. We conducted a systematic review of assessment tools for EBM TTT courses. To summarise and appraise existing assessment methods for teaching the teachers courses in EBM by a systematic review. Methods We searched PubMed, BioMed, EmBase, Cochrane and Eric databases without language restrictions and included articles that assessed its participants. Study selection and data extraction were conducted independently by two reviewers. Results Of 1230 potentially relevant studies, five papers met the selection criteria. There were no specific assessment tools for evaluating effectiveness of EBM TTT courses. Some of the material available might be useful in initiating the development of such an assessment tool. Conclusion There is a need for the development of educationally sound assessment tools for teaching the teachers courses in EBM, without which it would be impossible to ascertain if such courses have the desired effect

The effectiveness of a clinically integrated e-learning course in evidence-based medicine: A cluster randomised controlled trial

BACKGROUND: To evaluate the educational effects of a clinically integrated e-learning course for teaching basic evidence-based medicine (EBM) among postgraduates compared to a traditional lecture-based course of equivalent content. METHODS: We conducted a cluster randomised controlled trial in the Netherlands and the UK involving postgraduate trainees in six obstetrics and gynaecology departments. Outcomes (knowledge gain and change in attitude towards EBM) were compared between the clinically integrated e-learning course (intervention) and the traditional lecture based course (control). We measured change from pre- to post-intervention scores using a validated questionnaire assessing knowledge (primary outcome) and attitudes (secondary outcome). RESULTS: There were six clusters involving teaching of 61 postgraduate trainees (28 in the intervention and 33 in the control group). The intervention group achieved slightly higher scores for knowledge gain compared to the control, but these results were not statistically significant (difference in knowledge gain: 3.5 points, 95% CI -2.7 to 9.8, p = 0.27). The attitudinal changes were similar for both groups. CONCLUSION: A clinically integrated e-learning course was at least as effective as a traditional lecture based course and was well accepted. Being less costly than traditional teaching and allowing for more independent learning through materials that can be easily updated, there is a place for incorporating e-learning into postgraduate EBM curricula that offer on-the-job training for just-in-time learning. TRIAL REGISTRATION: Trial registration number: ACTRN12609000022268

Cause of Death and Predictors of All-Cause Mortality in Anticoagulated Patients With Nonvalvular Atrial Fibrillation : Data From ROCKET AF

M. Kaste on työryhmän ROCKET AF Steering Comm jäsen.Background-Atrial fibrillation is associated with higher mortality. Identification of causes of death and contemporary risk factors for all-cause mortality may guide interventions. Methods and Results-In the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF) study, patients with nonvalvular atrial fibrillation were randomized to rivaroxaban or dose-adjusted warfarin. Cox proportional hazards regression with backward elimination identified factors at randomization that were independently associated with all-cause mortality in the 14 171 participants in the intention-to-treat population. The median age was 73 years, and the mean CHADS(2) score was 3.5. Over 1.9 years of median follow-up, 1214 (8.6%) patients died. Kaplan-Meier mortality rates were 4.2% at 1 year and 8.9% at 2 years. The majority of classified deaths (1081) were cardiovascular (72%), whereas only 6% were nonhemorrhagic stroke or systemic embolism. No significant difference in all-cause mortality was observed between the rivaroxaban and warfarin arms (P=0.15). Heart failure (hazard ratio 1.51, 95% CI 1.33-1.70, P= 75 years (hazard ratio 1.69, 95% CI 1.51-1.90, P Conclusions-In a large population of patients anticoagulated for nonvalvular atrial fibrillation, approximate to 7 in 10 deaths were cardiovascular, whereasPeer reviewe

Mesenchymal stem cell-based therapy for ischemic stroke

Ischemic stroke represents a major, worldwide health burden with increasing incidence. Patients affected by ischemic strokes currently have few clinically approved treatment options available. Most currently approved treatments for ischemic stroke have narrow therapeutic windows, severely limiting the number of patients able to be treated. Mesenchymal stem cells represent a promising novel treatment for ischemic stroke. Numerous studies have demonstrated that mesenchymal stem cells functionally improve outcomes in rodent models of ischemic stroke. Recent studies have also shown that exosomes secreted by mesenchymal stem cells mediate much of this effect. In the present review, we summarize the current literature on the use of mesenchymal stem cells to treat ischemic stroke. Further studies investigating the mechanisms underlying mesenchymal stem cells tissue healing effects are warranted and would be of benefit to the field

shRNA-Mediated Decreases in c-Met Levels Affect the Differentiation Potential of Human Mesenchymal Stem Cells and Reduce Their Capacity for Tissue Repair

Mesenchymal stem cells/marrow stromal cells (MSC) are adult multipotent cells that can augment tissue repair. We previously demonstrated that culturing MSC in hypoxic conditions causes upregulation of the hepatocyte growth factor (HGF) receptor c-Met, allowing them to respond more robustly to HGF. MSC preconditioned in hypoxic environments contributed to restoration of blood flow after an ischemic injury more rapidly than MSC cultured in normoxic conditions. We now investigated the specific role of HGF/c-Met signaling in MSC function. An shRNA-mediated knockdown (KD) of c-Met in MSC did not alter their phenotypic profile, proliferation, or viability in vitro. However, we determined that while HGF/c-Met signaling does not play a role in the adipogenic differentiation of the cells, the disruption of this signaling pathway inhibited the ability of MSC to differentiate into the osteogenic and chondrogenic lineages. We next assessed the impact of c-Met KD on human MSC function in a xenogeneic hindlimb ischemia injury model. A 70% KD of c-Met in MSC resulted in a significant decrease in their capacity to regenerate blood flow to the ischemic limb, as compared to the MSC transduced with control shRNA. MSC with only a 60% KD of c-Met exhibited an intermediate capacity to restore blood flow, suggesting that MSC function is sensitive to the dosage of c-Met signaling. The current study highlights the significance of HGF/c-Met signaling in the capacity of MSC to restore blood flow after an ischemic injury and in their ability to differentiate into the osteogenic and chondrogenic lineages