We report a prospective multi-centre study of the clinical course and hospital management of thoracic empyema in 119 patients (mean age 54.8). The commonest presenting symptom was malaise (75%), 55% were febrile; 31% were previously well with no predisposing condition. Initial treatments were antibiotics alone (5), needle aspirations (46), intercostal tube drainage (61), rib resection (3) and decortication (4). Overall, intercostal drainage was used in 77 patients (16 failed aspirations), surgical rib resection in 24 (1 failed aspirations, 20 failed drainage), and surgical decortication in 28 (6 failed aspirations, 17 failed drainage). Only 4 patients received intrapleural fibrinolytic agents. Aspiration and drainage were likely to fail if the empyema was > 40% of the hemithorax. Median time from treatment start to discharge was: aspirations, 26 days; drainage, 23 days; resection 11 days; decortication, 12 days. Overall 21 patients died (12 with empyema as the major cause); two had been surgically treated. Mortality correlated with age, diabetes, heart failure, and low serum albumin at admission. Infecting organisms, identified in 109 patients (92%) included anaerobes (37), Str. melleri (36), and Str. pneumoniae (28). Six months after discharge, all but six survivors had regained their previous health.

SignificanceAminoglycosides are well known as antibiotics that target the bacterial ribosome. However, they also impact the eukaryotic translation mechanism to promote read-through of premature termination codons (PTCs) in mRNA. Aminoglycosides are therefore considered as potential therapies for PTC-associated human diseases. Here, we performed a comprehensive study of the mechanism of action of aminoglycosides in eukaryotes by applying a combination of structural and functional approaches. Our findings reveal complex interactions of aminoglycosides with eukaryotic 80S ribosome caused by their multiple binding sites, which lead to inhibition of intersubunit movement within the human ribosome that impact nearly every aspect of protein synthesis.

No abstract

SummaryRibosomal processing requires a series of endo- and exonucleolytic steps for the production of mature ribosomes, of which most have been described. To ensure ribosome synthesis, 3′ end formation of rRNA uses multiple nucleases acting in parallel; however, a similar parallel mechanism had not been described for 5′ end maturation. Here, we identify Rrp17p as a previously unidentified 5′–3′ exonuclease essential for ribosome biogenesis, functioning with Rat1p in a parallel processing pathway analogous to that of 3′ end formation. Rrp17p is required for efficient exonuclease digestion of the mature 5′ ends of 5.8SS and 25S rRNAs, contains a catalytic domain close to its N terminus, and is highly conserved among higher eukaryotes, being a member of a family of exonucleases. We show that Rrp17p binds late pre-60S ribosomes, accompanying them from the nucleolus to the nuclear periphery, and provide evidence for physical and functional links between late 60S subunit processing and export.

SUMMARY The regulation of protein synthesis contributes to gene expression in both normal physiology and disease, yet kinetic investigations of the human translation mechanism are currently lacking. Using single-molecule fluorescence imaging methods, we have quantified the nature and timing of structural processes in human ribosomes during single-turnover and processive translation reactions. These measurements reveal that functional complexes exhibit dynamic behaviors and thermodynamic stabilities distinct from those observed for bacterial systems. Structurally defined sub-states of pre- and post-translocation complexes were sensitive to specific inhibitors of the eukaryotic ribosome demonstrating the utility of this platform to probe drug mechanism. The application of three-color single-molecule FRET methods further revealed a long-distance allosteric coupling between distal tRNA binding sites within ribosomes bearing three tRNAs, which contributed to the rate of processive translation.