Loss of nuclear UBE3A activity is the predominant cause of Angelman syndrome in individuals carrying UBE3A missense mutations.

Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by deletion (~75%) or mutation (~10%) of the ubiquitin E3 ligase A (UBE3A) gene, which encodes a HECT type E3 ubiquitin protein ligase. Although the critical substrates of UBE3A are unknown, previous studies have suggested a critical role of nuclear UBE3A in AS pathophysiology. Here, we investigated to what extent UBE3A missense mutations disrupt UBE3A subcellular localization as well as catalytic activity, stability and protein folding. Our functional screen of 31 UBE3A missense mutants revealed that UBE3A mislocalization is the predominant cause of UBE3A dysfunction, accounting for 55% of the UBE3A mutations tested. The second major cause (29%) is a loss of E3-ubiquitin ligase activity, as assessed in an Escherichia coli in vivo ubiquitination assay. Mutations affecting catalytic activity are found not only in the catalytic HECT domain, but also in the N-terminal half of UBE3A, suggesting an important contribution of this N-terminal region to its catalytic potential. Together, our results show that loss of nuclear UBE3A E3 ligase activity is the predominant cause of UBE3A-linked AS. Moreover, our functional analysis screen allows rapid assessment of the pathogenicity of novel UBE3A missense variants which will be of particular importance when treatments for AS become available.

Are dorsal ramus nerve blocks the solution to postoperative lumbar spine surgery pain?

BACKGROUND: Open lumbar spine surgery typically results in significant post-operative pain. Most pain protocols promote a multimodal approach aiming to reduce opiate requirements. This case-matched, prospective clinical study aims to establish the efficacy of dorsal ramus nerve root (DRN) blocks for post-operative analgesia. METHODS: We conducted a case-control observational, single centre, prospective study of 15 consecutive patients who had DRN block for a single-level lumbar discectomy or one/two-level lumbar spinal decompression, from Jan 2018 to Jun 2018. These were case matched with a field infiltration group. We analyse for differences in mean and maximum rest pain scores, opiate requirement, mobilisation status and length of stay (LoS). RESULTS: No differences were seen in pain scores in the first 24 hours post-operation for DRN block vs. field infiltration groups (2.8 vs. 2.7, P=0.90). No reduction in the morphine sulphate equivalents dosage requirement was seen in the DRN group (43.1±46.4 vs. 37.6±33.5, P=0.26). Similar proportions of patients mobilised early (P=1.0) and the mean LoS was 1.7 vs. 1.8 days (P=0.81). CONCLUSIONS: Dorsal ramus nerve block is not superior to local anaesthetic field infiltration of surgical wound in minor one or two level lumbar spinal decompression surgery in terms of alleviating pain, reducing opiate requirements, or facilitating earlier mobilisation and discharge.

A Robust Approach to Implementing Fascia Iliaca Compartment Nerve Blocks in Hip Fracture Patients.

BACKGROUND: A clear imperative exists to optimize the preoperative pain management of hip fracture patients. Increasingly, fascia iliaca compartment blocks (FICBs) are being effectively utilized as an adjunct to oral analgesia in the emergency department. PURPOSE: We investigated the feasibility, safety, and delivery rate when junior doctors and specialist nurses are trained in FICBs delivery, alongside the introduction of a step-by-step proforma. METHODS: We conducted a retrospective study of hip fractures patients presenting preinterventions (n = 138) between October and December 2014 and postinterventions (n = 246) between April and August 2015. Outcomes analyzed included delivery frequency, anesthetic dosages used, and procedure documentation. RESULTS: Preintervention, FICB was performed in 40% (n = 51) of eligible patients, with an improvement to 72% (n = 160) postintervention. Postinterventions, 98% of FICBs were performed with the anesthetic dose recommended-a prescription between 75 and 100 mg of 0.25% levobupivacaine. No adverse patient outcomes, relating to the interventions implemented, were noted during the study period. CONCLUSION: Delivery of FICB by junior doctors and specialist nurses in the emergency department is feasible, safe, and improves the proportion of patients receiving blocks.

Genes to predict VO2max trainability: a systematic review.

BACKGROUND: Cardiorespiratory fitness (VO2max) is an excellent predictor of chronic disease morbidity and mortality risk. Guidelines recommend individuals undertake exercise training to improve VO2max for chronic disease reduction. However, there are large inter-individual differences between exercise training responses. This systematic review is aimed at identifying genetic variants that are associated with VO2max trainability. METHODS: Peer-reviewed research papers published up until October 2016 from four databases were examined. Articles were included if they examined genetic variants, incorporated a supervised aerobic exercise intervention; and measured VO2max/VO2peak pre and post-intervention. RESULTS: Thirty-five articles describing 15 cohorts met the criteria for inclusion. The majority of studies used a cross-sectional retrospective design. Thirty-two studies researched candidate genes, two used Genome-Wide Association Studies (GWAS), and one examined mRNA gene expression data, in addition to a GWAS. Across these studies, 97 genes to predict VO2max trainability were identified. Studies found phenotype to be dependent on several of these genotypes/variants, with higher responders to exercise training having more positive response alleles than lower responders (greater gene predictor score). Only 13 genetic variants were reproduced by more than two authors. Several other limitations were noted throughout these studies, including the robustness of significance for identified variants, small sample sizes, limited cohorts focused primarily on Caucasian populations, and minimal baseline data. These factors, along with differences in exercise training programs, diet and other environmental gene expression mediators, likely influence the ideal traits for VO2max trainability. CONCLUSION: Ninety-seven genes have been identified as possible predictors of VO2max trainability. To verify the strength of these findings and to identify if there are more genetic variants and/or mediators, further tightly-controlled studies that measure a range of biomarkers across ethnicities are required.

Biochemical derangements prior to emergency laparotomy at Queen Elizabeth Central Hospital, Blantyre, Malawi: A cross-sectional pilot study.

BACKGROUND: The aim of this study was to examine biochemical investigations not routinely performed prior to emergency laparotomy in patients at Queen Elizabeth Central Hospital, a low-resource public hospital in Blantyre, Malawi. METHODS: A prospective cross-sectional study of adults (N = 15) needing emergency laparotomy over a 4-week period were studied at Queen Elizabeth Central Hospital. Biochemical investigations, not routinely performed for economic reasons, were performed preoperatively; these included sodium, potassium, chloride, carbon dioxide, urea, and calcium levels. RESULTS: Gastrointestinal pathology was predominant among the emergency laparotomies performed. Large bowel obstruction and bowel perforation secondary to typhoid were most frequent. Clinically significant biochemical derangements among the study patients were as follows: cases of moderate-to-severe hypokalaemia (n = 2), severe hyponatraemia (n = 1), moderate hypernatraemia (n = 1), and severe hypocalcaemia (n = 1). The most frequent abnormalities seen were uraemia and hypochloraemia (n = 11). CONCLUSIONS: Accurate electrolyte estimation in critically ill preoperative patients is desireable for optimal perioperative management but frequently absent in resource-challenged environments.

Functional outcomes of laminectomy and laminotomy for the surgical management lumbar spine stenosis.

BACKGROUND: This clinical descriptive study aims to establish if differences exist in functional outcomes, to include both leg and lower back pain (LBP) as well as disability, in patients undergoing laminectomy or laminotomy surgery for lumbar spinal stenosis (LSS). METHODS: We conducted a single centre, prospective study of 119 patients undergoing laminectomy or laminotomy surgery for LSS, from 2006 and 2012. Clinical outcomes for back and leg pain were analyses using Oswestry Disability Index (ODI) questionnaires and visual analogue scale (VAS) scores collected preoperatively, at 6 weeks and 1 year. Further analysis subdivided patients into two groups based on initial LBP VAS scores. RESULTS: Fifty-five percent of patients were females (n=65) and 45% males (n=54), with a mean age of 68.7 years and L4/5 being the level most frequently decompressed. Considering all surgeries, a statistically significant reduction in VAS back pain between pre-op and 6 weeks was seen (4.99 to 3.00, P<0.001). There was a significant (P<0.0001) average reductions in LBP by 1.66 units and leg pain by 3.33 units after 1 year, with minimal difference between laminectomy and laminotomy. In the VAS back ≥5 group, laminectomy patient's pain increased by 0.63 units between 6 weeks and 1 year whilst laminotomy patients experienced a reduction in back pain of 0.51 units (P=0.063). ODI scores significantly improved for laminectomy and laminotomy by an average of 19.1%, 95% CI: 13.4-24.9% and 10.8%, 95% CI: 5.8-15.7%, with no statistically significant difference between groups. CONCLUSIONS: No statistically significant differences were demonstrated between laminectomy and laminotomy outcomes, for LBP, leg pain or disability in our institute. On the basis of functional outcomes laminectomy remains a feasible approach in the treatment of lumbar spine stenosis. The data presented in this manuscript provides frequency data for subsequent comparative studies.

Directed mutagenesis alters the stereochemistry of catalysis by isolated ketoreductase domains from the erythromycin polyketide synthase.

The ketoreductase (KR) domains eryKR(1) and eryKR(2) from the erythromycin-producing polyketide synthase (PKS) reduce 3-ketoacyl-thioester intermediates with opposite stereospecificity. Modeling of eryKR(1) and eryKR(2) showed that conserved amino acids previously correlated with production of alternative alcohol configurations lie in the active site. eryKR(1) domains mutated at these positions showed an altered stereochemical outcome in reduction of (2R, S)-2-methyl-3-oxopentanoic acid N-acetylcysteamine thioester. The wild-type eryKR(1) domain exclusively gave the (2S, 3R)-3-hydroxy-2-methylpentanoic acid N-acetylcysteamine thioester, while the double mutant (F141W, P144G) gave only the (2S, 3S) isomer, a switch of the alcohol stereochemistry. Mutation of the eryKR(2) domain, in contrast, greatly increased the proportion of the wild-type (2R, 3S)-alcohol product. These data confirm the role of key residues in stereocontrol and suggest an additional way to make rational alterations in polyketide antibiotic structure.

Sociotropy and autonomy: an examination of interpersonal and work adjustment.

One-hundred and sixty-five undergraduate students completed measures of sociotropy, autonomy, and adjustment. Autonomy was associated with poor social adjustment but was not associated with work role adjustment. Sociotropy failed to evidence a significant relation with work role or social adjustment. In past research, autonomy has primarily been theorized to contribute to depression when achievement needs are not met. Our results raise the possibility that autonomy may be linked to depression through the pathway of low social support and interpersonal difficulties. In addition, the results suggest that sociotropic individuals may not have objectively poor social adjustment despite their concerns regarding this area. Likewise, autonomous individuals may not have better or worse work adjustment despite their efforts to achieve.

A novel type of deubiquitinating enzyme.

A previous report from this laboratory described two novel proteins that have sequence similarity to A20, a negative regulator of NF-kappaB (Evans, P. C., Taylor, E. R., Coadwell, J., Heyninck, K., Beyaert, R., and Kilshaw, P. J. (2001) Biochem. J. 357, 617-623). One of these molecules, cellular zinc finger anti-NF-kappaB (Cezanne), a 100-kDa cytoplasmic protein, also suppressed NF-kappaB. Here we demonstrate that Cezanne is a novel deubiquitinating enzyme, distinct from the two known families of deubiquitinases, Types I and II. We show that Cezanne contains an N-terminal catalytic domain that belongs to the recently discovered ovarian tumor protein (OTU) superfamily, a group of proteins displaying structural similarity to cysteine proteases but having no previously described function. Recombinant Cezanne cleaved ubiquitin monomers from linear or branched synthetic ubiquitin chains and from ubiquitinated proteins. Mutation of a conserved cysteine residue in the catalytic site of the proteolytic domain caused Cezanne to co-precipitate polyubiquitinated cellular proteins. We also provide evidence for an additional ubiquitin binding site in the C-terminal part of the molecule. Our data provide the first demonstration of functional activity among OTU proteins.

Running rings around RNA: a superfamily of phosphate-dependent RNases.

The exosome of Saccharomyces cerevisiae and the degradosome of Escherichia coli are multienzyme complexes involved in the degradation of mRNA. Both contain enzymes that are similar to the phosphate-dependent exoribonuclease RNase PH. These enzymes are phosphorylases that degrade RNA from the 3'-end. A recent X-ray crystallographic study of the polynucleotide phosphorylase (PNPase) from Streptomyces antibioticus reveals, for the first time, the atomic structure of a member of the RNase PH superfamily. Here, information from the structure of PNPase is used to address two related issues. First, the structure supports the idea that PNPase, which is a trimer of multidomain subunits, arose by duplication of a gene encoding an RNase PH-like enzyme. Second, the structure might explain how RNase PH-like enzymes associate into oligomeric rings that degrade RNA in a processive reaction.