BACKGROUND: Acute surgical assessment units (ASAUs) aim to optimise management of surgical patients compared to the traditional \'on-call\' emergency department (ED) system. Acute appendicitis (AA) is the most common acute surgical condition requiring emergency surgery.
OBJECTIVE: We set out to assess if the ASAU improved care provided to patients with AA compared to those managed through the ED.
METHODS: Patients admitted via the ED with AA in the 6 months prior to opening the ASAU were compared to those admitted via the ASAU in the first six months following its implementation. Relevant data was collected on key performance indicators from their charts.
RESULTS: In the ASAU cohort, the mean time to be seen was one hour less than the ED cohort (21 min vs 74 min). The mean time to surgery was also 8.8 h shorter. Most patients in the ASAU group (78.6%) underwent surgery during the day, compared to 40.3% of ED patients. The ASAU patients also had a lower postoperative complication rate (0.9% vs 3.9%), as well as a lower negative appendicectomy rate (14.2% vs 18.6%) and lower conversion-to-open surgery rate. Greater consultant supervision and presence was observed.
CONCLUSIONS: The ASAU has resulted in better outcomes for patients with AA than those admitted via ED. More operations were performed in safer daytime hours with greater consultant presence, allowing for improved senior support for trainee surgeons. Our study supports the role of the ASAU in improving the quality and efficiency of emergency general surgery.

BACKGROUND: The acute surgical unit (ASU) model of care is a new paradigm shift in the provision of emergency surgery. Clinical and non-clinical outcomes have been described after the introduction of the ASU model in Australia and New Zealand. This paper reviews and analyses the current published literature and methods of implementation of contemporary ASU models.
METHODS: We conducted a comprehensive database search to identify all relevant published papers pertaining to the ASU. Included papers compared ASU models to emergency surgery\'s traditional model of care. Relevant clinical and non-clinical end points were extracted for analysis.
RESULTS: Seven papers and two abstracts published data assessing clinical and non-clinical end points within the ASU. Four out of six studies reported a reduction in hospital length of stay. Two out of three studies showed reduction in mean time to emergency department review and two out of four studies reported a reduction in time to surgery. Additionally, four out of five studies showed a reduction in after hours operating with an ASU model.
CONCLUSIONS: Trends in clinical outcomes are seen including reduced length of stay, time to emergency department assessment and surgery, supplemented by non-clinical outcomes including reduced after hours operating and the potential for increased training opportunities. The published data presents certain weaknesses and further information is required to appreciate the applicability of certain aspects of the ASU model to smaller centres.

Sulfonucleotide reductases catalyse the first reductive step of sulfate assimilation. Their substrate specificities generally correlate with the requirement for a [Fe4S4] cluster, where adenosine 5\'-phosphosulfate (APS) reductases possess a cluster and 3\'-phosphoadenosine 5\'-phosphosulfate reductases do not. The exception is the APR-B isoform of APS reductase from the moss Physcomitrella patens, which lacks a cluster. The crystal structure of APR-B, the first for a plant sulfonucleotide reductase, is consistent with a preference for APS. Structural conservation with bacterial APS reductase rules out a structural role for the cluster, but supports the contention that it enhances the activity of conventional APS reductases.

Tn916-like conjugative transposons carrying antibiotic resistance genes are found in a diverse range of bacteria. Orf14 within the conjugation module encodes a bifunctional cell wall hydrolase CwlT that consists of an N-terminal bacterial lysozyme domain (N-acetylmuramidase, bLysG) and a C-terminal NlpC/P60 domain (γ-d-glutamyl-l-diamino acid endopeptidase) and is expected to play an important role in the spread of the transposons. We determined the crystal structures of CwlT from two pathogens, Staphylococcus aureus Mu50 (SaCwlT) and Clostridium difficile 630 (CdCwlT). These structures reveal that NlpC/P60 and LysG domains are compact and conserved modules, connected by a short flexible linker. The LysG domain represents a novel family of widely distributed bacterial lysozymes. The overall structure and the active site of bLysG bear significant similarity to other members of the glycoside hydrolase family 23 (GH23), such as the g-type lysozyme (LysG) and Escherichia coli lytic transglycosylase MltE. The active site of bLysG contains a unique structural and sequence signature (DxxQSSES+S) that is important for coordinating a catalytic water. Molecular modeling suggests that the bLysG domain may recognize glycan in a similar manner to MltE. The C-terminal NlpC/P60 domain contains a conserved active site (Cys-His-His-Tyr) that appears to be specific to murein tetrapeptide. Access to the active site is likely regulated by isomerism of a side chain atop the catalytic cysteine, allowing substrate entry or product release (open state), or catalysis (closed state).

X-ray crystal structures of bc1 complexes obtained over the last 15 years have provided a firm structural basis for our understanding of the complex. For the most part there is good agreement between structures from different species, different crystal forms, and with different inhibitors bound. In this review we focus on some of the remaining unexplained differences, either between the structures themselves or the interpretations of the structural observations. These include the structural basis for the motion of the Rieske iron-sulfur protein in response to inhibitors, a possible conformational change involving tyrosine132 of cytochrome (cyt) b, the presence of cis-peptides at the beginnings of transmembrane helices C, E, and H, the structural insight into the function of the so-called \"Core proteins\", different modelings of the retained signal peptide, orientation of the low-potential heme b, and chirality of the Met ligand to heme c1. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.