Controlled assembly of SNAP-PNA-fluorophore systems on DNA templates to produce fluorescence resonance energy transfer

The SNAP protein is a widely used self-labeling tag that can be used for tracking protein localization and trafficking in living systems. A model system providing controlled alignment of SNAP-tag units can provide a new way to study clustering of fusion proteins. In this work, fluorescent SNAP-PNA conjugates were controllably assembled on DNA frameworks forming dimers, trimers, and tetramers. Modification of peptide nucleic acid (PNA) with the O6-benzyl guanine (BG) group allowed the generation of site-selective covalent links between PNA and the SNAP protein. The modified BG-PNAs were labeled with fluorescent Atto dyes and subsequently chemo-selectively conjugated to SNAP protein. Efficient assembly into dimer and oligomer forms was verified via size exclusion chromatography (SEC), electrophoresis (SDS-PAGE), and fluorescence spectroscopy. DNA directed assembly of homo- and hetero-dimers of SNAP-PNA constructs induced homo- and hetero-FRET, respectively. Longer DNA scaffolds controllably aligned similar fluorescent SNAP-PNA constructs into higher oligomers exhibiting homo-FRET. The combined SEC and homo-FRET studies indicated the 1:1 and saturated assemblies of SNAP-PNA-fluorophore:DNA formed preferentially in this system. This suggested a kinetic/stoichiometric model of assembly rather than binomially distributed products. These BG-PNA-fluorophore building blocks allow facile introduction of fluorophores and/or assembly directing moieties onto any protein containing SNAP. Template directed assembly of PNA modified SNAP proteins may be used to investigate clustering behavior both with and without fluorescent labels which may find use in the study of assembly processes in cells

Gaviscon® vs. omeprazole in symptomatic treatment of moderate gastroesophageal reflux. a direct comparative randomised trial

<p>Abstract</p> <p>Background</p> <p>Medical management of GERD mainly uses proton pump inhibitors. Alginates also have proven efficacy. The aim of this trial was to compare short-term efficacy of an alginate (Gaviscon^®, 4 × 10 mL/day) and omeprazole (20 mg/day) on GERD symptoms in general practice.</p> <p>Methods</p> <p>A 14-day multicentre randomised double-blind double-dummy non-inferiority trial compared Gaviscon^®(4 × 10 mL/day) and omeprazole (20 mg/day) in patients with 2-6 day heartburn episodes weekly without alarm signals. The primary outcome was the mean time to onset of the first 24-h heartburn-free period after initial dosing. Secondary outcomes were the proportion of patients without heartburn by D7, pain relief by D7, and reduction in pain intensity by D7 and D14.</p> <p>Results</p> <p>278 patients were recruited; 120 were included in the Gaviscon^®group and 121 in the omeprazole group for the per protocol non-inferiority analysis. The mean time to onset of the first 24-h heartburn-free period after initial dosing was 2.0 (± 2.2) days for Gaviscon^®and 2.0 (± 2.3) days for omeprazole (<it>p </it>= 0.93); mean intergroup difference was 0.01 ± 1.55 days (95% CI = -0.41 to 0.43): i.e., less than the lower limit of the 95% CI of -0.5 days predetermined to demonstrate non-inferiority. The mean number of heartburn-free days by D7 was significantly greater in the omeprazole group: 3.7 ± 2.3 days vs. 3.1 ± 2.1 (<it>p </it>= 0.02). On D7, overall quality of pain relief was slightly in favour of omeprazole (<it>p </it>= 0.049). There was no significant difference in the reduction in pain intensity between groups by D7 (<it>p = </it>0.11) or D14 (<it>p = </it>0.08). Tolerance and safety were good and comparable in both groups.</p> <p>Conclusion</p> <p>Gaviscon^®was non-inferior to omeprazole in achieving a 24-h heartburn-free period in moderate episodic heartburn, and is a relevant effective alternative treatment in moderate GERD in primary care.</p> <p>Trial registration</p> <p><a href="http://www.controlled-trials.com/ISRCTN62203233">ISRCTN62203233</a>.</p

A prospective observational study of a cohort of outpatients with an acute medical event and reduced mobility: incidence of symptomatic thromboembolism and description of thromboprophylaxis practices.

OBJECTIVES: The study was performed to determine the incidence of symptomatic venous thromboembolism in outpatients with an acute medical event causing temporary reduced mobility. Risk factors for venous thromboembolism and thromboprophylaxis practices were also studied. DESIGN: This was a prospective, observational, multicentre, cohort study. SETTING: General practitioners randomly selected from a registry of 25,000 active representative doctors in France including eligible outpatients. SUBJECTS: Outpatients aged at least 40 years anticipated to have reduced mobility for at least 48 h due to an acute medical event were eligible. INTERVENTIONS: None required. MAIN OUTCOME MEASURES: Symptomatic deep-vein thrombosis and pulmonary embolism at 3 weeks were the main study end-points. RESULTS: Overall, 16,532 evaluable patients of mean age 71 years were recruited between October 2002 and June 2003 by 2895 doctors. The main acute medical events leading to reduced mobility were infection, acute rheumatism and falls without fracture. The incidence rates (95% confidence interval) of symptomatic deep-vein thrombosis and pulmonary embolism were 1% (0.84-1.14) and 0.20% (0.13-0.27) respectively. Venous insufficiency in legs, cancer, and a personal or family history of venous thromboembolism were independent risk factors for venous thromboembolism. Pharmacological thromboprophylaxis was initiated in 35.0% (n=5782) of the patients. The principal driver of prescription was a personal history of venous thromboembolism. CONCLUSIONS: The risk of symptomatic venous thromboembolism in outpatients with reduced mobility for medical reasons is close to that reported in medical and surgical inpatients. This risk and the potential need for thromboprophylaxis should be taken into account by primary care doctors

La vaccination contre la Covid-19 : le vaccin Comirnaty de Pfizer-BioNtech

Le conseil scientifique du CNGE a rédigé un outil d'aide à la décision pour les médecins généralistes concernant la vaccination contre la COVID-19. Il s'agit d'aider le clinicien à discuter des données scientifiques avec le patient pour l'aider à prendre une décision