Long-term follow up of factual knowledge after a single, randomised problem-based learning course

BACKGROUND: The long-term effect of problem-based learning (PBL) on factual knowledge is poorly investigated. We took advantage of a previous randomised comparison between PBL and traditional teaching in a 3(rd )year course to follow up factual knowledge of the students during their 4(th )and 5(th )year of medical school training. METHODS: 3(rd )year medical students were initially randomized to participate in a problem-based (PBL, n = 55), or a lecture-based (LBL, n = 57) course in basic pharmacology. Summative exam results were monitored 18 months later (after finishing a lecture-based course in clinical pharmacology). Additional results of an unscheduled, formative exam were obtained 27 months after completion of the first course. RESULTS: Of the initial sample of 112 students, 90 participated in the second course and exam (n = 45, 45). 32 (n = 17 PBL, n = 15 LBL) could be exposed to the third, formative exam. Mean scores (± SD) were 22.4 ± 6.0, 27.4 ± 4.9 and 20.1 ± 5.0 (PBL), or 22.2 ± 6.0, 28.4 ± 5.1 and 19.0 ± 4.7 (LBL) in the first, second and third test, respectively (maximum score: 40). No significant differences were found between the two groups. CONCLUSION: A small-scale exposure to PBL, applied under randomized conditions but in the context of a traditional curriculum, does not sizeably change long-term presence of factual knowledge within the same discipline

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Thirty-day outcomes of the Cardioband tricuspid system for patients with symptomatic functional tricuspid regurgitation: The TriBAND study.

BACKGROUND Severe tricuspid regurgitation (TR) has limited treatment options and is associated with high morbidity and mortality. AIMS We evaluated the safety and effectiveness of the Cardioband tricuspid valve reconstruction system from the ongoing European single-arm, multicentre, prospective TriBAND post-market clinical follow-up study. METHODS Eligible patients had chronic symptomatic functional TR despite diuretic therapy and were deemed candidates for transcatheter tricuspid repair by the local Heart Team. RESULTS Sixty-one patients had ≥severe functional TR. At baseline, 85% of patients were in NYHA Class III-IV, 94% had ≥severe TR (core laboratory-assessed) with 6.8% EuroSCORE II and 53% LVEF. Device success was 96.7%. At discharge, 59% (p<0.001) of patients achieved ≤moderate TR and 78% had at least one grade TR reduction. At 30 days, all-cause mortality and composite MAE rates were 1.6% and 19.7%, respectively; septolateral annular diameter was reduced by 20%, where 69% of patients achieved ≤moderate TR and 85% of patients had at least one grade TR reduction (all p<0.001). Mid-RVEDD, RA volume, and IVC diameter decreased by 10% (p=0.005), 21% (p<0.001), and 11% (p=0.022), respectively; 74% were in NYHA Class I-II (p<0.001) with improvements in overall KCCQ score by 17 points (p<0.001). CONCLUSIONS In the TriBAND study, the Cardioband tricuspid system demonstrated favourable outcomes at discharge and 30 days in a challenging patient population with symptomatic ≥severe functional TR. Results showed significant reductions in annular diameter and TR severity, accompanied by early evidence of right heart remodelling and improvements in functional status and quality of life