Transmitochondrial embryonic stem cells containing pathogenic mtDNA mutations are compromised in neuronal differentiation

Objectives:  Defects of the mitochondrial genome (mtDNA) cause a series of rare, mainly neurological disorders. In addition, they have been implicated in more common forms of movement disorders, dementia and the ageing process. In order to try to model neuronal dysfunction associated with mitochondrial disease, we have attempted to establish a series of transmitochondrial mouse embryonic stem cells harbouring pathogenic mtDNA mutations. Materials and methods: Transmitochondrial embryonic stem cell cybrids were generated by fusion of cytoplasts carrying a variety of mtDNA mutations, into embryonic stem cells that had been pretreated with rhodamine 6G, to prevent transmission of endogenous mtDNA. Cybrids were differentiated into neurons and assessed for efficiency of differentiation and electrophysiological function. Results:  Neuronal differentiation could occur, as indicated by expression of neuronal markers. Differentiation was impaired in embryonic stem cells carrying mtDNA mutations that caused severe biochemical deficiency. Electrophysiological tests showed evidence of synaptic activity in differentiated neurons carrying non-pathogenic mtDNA mutations or in those that caused a mild defect of respiratory activity. Again, however, neurons carrying mtDNA mutations that resulted in severe biochemical deficiency had marked reduction in post-synaptic events. Conclusions:  Differentiated neurons carrying severely pathogenic mtDNA defects can provide a useful model for understanding how such mutations can cause neuronal dysfunction

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Abciximab for thrombolysis during intracranial aneurysm coiling

Introduction: Thrombotic events are a common and severe complication of endovascular aneurysm treatment with significant impact on patients' outcome. This study evaluates risk factors for thrombus formation and assesses the efficacy and safety of abciximab for clot dissolution. Materials and methods: All patients treated with abciximab during (41 patients) or shortly after (22 patients) intracranial aneurysm coil embolisation were retrieved from the institutional database (2000 to 2007, 1,250 patients). Sixty-three patients (mean age, 55.3years, ±12.8) had received either intra-arterial or intravenous abciximab. Risk factors for clot formation were assessed and the angiographic and clinical outcome evaluated. Results: No aneurysm rupture occurred during or after abciximab application. The intra-procedural rate of total recanalisation was 68.3%. Thromboembolic complications were frequently found in aneurysms of the Acom complex and of the basilar artery, whilst internal carotid artery aneurysms were underrepresented. Two patients died of treatment-related intracranial haemorrhages into preexisting cerebral infarcts. Two patients developed a symptomatic groin haematoma. Conclusions: Abciximab is efficacious and safe for thrombolysis during and after endovascular intracranial aneurysm treatment in the absence of preexisting ischaemic strok

Aqueous Radical Initiated Oxidation of an Organic Monolayer at the Air–Water Interface as a Proxy for Thin Films on Atmospheric Aerosol Studied with Neutron Reflectometry

Neutron reflectometry has been used to study the radical initiated oxidation of a monolayer of the lipid 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) at the air-water interface, by aqueous-phase hydroxyl, sulfate and nitrate radicals. The oxidation of organic films at the surface of atmospheric aqueous aerosols can influence the optical properties of aerosol and consequently can impact the Earth’s radiative balance and contribute to modern climate change. The amount of material at the air-water interface was found to decrease on exposure to aqueous-phase radicals and follow a multi-step degradation mechanism. The multi-step degradation mechanism means that lipid molecules in the thin film degrade to form progressively shorter chain surface active products and several reactive steps are required to remove the film from the air-water interface. Calculations to determine the film lifetime indicate that it will take ~4-5 days for the film to degrade to 50 % of its initial amount in the atmosphere and therefore attack by aqueous radicals on organic films is atmospherically important relative to the typical lifetimes of atmospheric aerosol

A TPX2 Proteomimetic Has Enhanced Affinity for Aurora-A Due to Hydrocarbon Stapling of a Helix

Inhibition of protein kinases using ATP-competitive compounds is an important strategy in drug discovery. In contrast, the allosteric regulation of kinases through the disruption of protein-protein interactions has not been widely adopted, despite the potential for selective targeting. Aurora-A kinase regulates mitotic entry and mitotic spindle assembly and is a promising target for anticancer therapy. The microtubule-associated protein TPX2 activates Aurora-A through binding to two sites. Aurora-A recognition is mediated by two motifs within the first 43 residues of TPX2, connected by a flexible linker. To characterize the contributions of these three structural elements, we prepared a series of TPX2 proteomimetics and investigated their binding affinity for Aurora-A using isothermal titration calorimetry. A novel stapled TPX2 peptide was developed that has improved binding affinity for Aurora-A and mimics the function of TPX2 in activating Aurora-A's autophosphorylation. We conclude that the helical region of TPX2 folds upon binding Aurora-A, and that stabilization of this helix does not compromise Aurora-A activation. This study demonstrates that the preparation of these proteomimetics using modern synthesis methods is feasible and their biochemical evaluation demonstrates the power of proteomimetics as tool compounds for investigating PPIs involving intrinsically disordered regions of proteins

Experimentally engineered mutations in a ubiquitin hydrolase, UBP-1, modulate in vivo susceptibility to artemisinin and chloroquine in Plasmodium berghei

As resistance to artemisinins (current frontline drugs in malaria treatment) emerges in south East Asia, there is an urgent need to identify the genetic determinants and understand the molecular mechanisms underpinning such resistance. Such insights could lead to prospective interventions to contain resistance and prevent the eventual spread to other malaria endemic regions. Artemisinin reduced susceptibility in South East Asia (SEA) has been primarily linked to mutations in P. falciparum Kelch-13, which is currently widely recognised as a molecular marker of artemisinin resistance. However, 2 mutations in a ubiquitin hydrolase, UBP-1, have been previously associated with artemisinin reduced susceptibility in a rodent model of malaria and some cases of UBP-1 mutation variants associating with artemisinin treatment failure have been reported in Africa and SEA. In this study, we have employed CRISPR-Cas9 genome editing and pre-emptive drug pressures to test these artemisinin susceptibility associated mutations in UBP-1 in P. berghei sensitive lines in vivo. Using these approaches, we have shown that the V2721F UBP-1 mutation results in reduced artemisinin susceptibility, while the V2752F mutation results in resistance to chloroquine and moderately impacts tolerance to artemisinins. Genetic reversal of the V2752F mutation restored chloroquine sensitivity in these mutant lines while simultaneous introduction of both mutations could not be achieved and appears to be lethal. Interestingly, these mutations carry a detrimental growth defect, which would possibly explain their lack of expansion in natural infection settings. Our work has provided independent experimental evidence on the role of UBP-1 in modulating parasite responses to artemisinin and chloroquine under in vivo conditions

Amino acid intakes are associated with bone mineral density and prevalence of low bone mass in women: evidence from discordant monozygotic twins

Although a higher protein intake, particularly from vegetable sources, has been shown to be associated with higher bone mineral density (BMD) the relative impact of specific amino acids (AA) on BMD and risk of osteoporosis remains to be determined. Mechanistic research suggests that a number of specific AA, including five non-essential AA, alanine, arginine, glutamic acid, glycine and proline, may play a role in bone health, principally through improved production of insulin and insulin-like growth factor 1 and the synthesis of collagen and muscle protein. However to date, no previous studies have examined the associations between habitual intake of AA and direct measures of BMD and prevalence of osteoporosis or osteopenia and no studies have examined this relationship in discordant identical twin-pairs. In these analyses of female monozygotic twin-pairs discordant for AA intake (n=135), twins with higher intakes of alanine and glycine had significantly higher BMD at the spine than their co-twins with within-pair differences in spine-BMD of 0.012 g/cm2 (SE 0.01 P=0.039) and 0.014g/cm2 (SE 0.01 P=0.026) respectively. Furthermore, in cross-sectional multivariable analyses of 3160 females aged 18-79y, a higher intake of total protein was significantly associated with higher DXA-measured BMD at the spine (Q4-Q1 0.017g/cm2 SE 0.01 P=0.035) and forearm (Q4-Q1 0.010g/cm2 SE 0.003 P=0.002). Intake of six AA (alanine, arginine, glutamic acid, leucine, lysine and proline) were associated with higher BMD at the spine and forearm with the strongest association observed for leucine (Q4-Q1 0.024g/cm2 SE 0.01 P=0.007). When intakes were stratified by protein source, vegetable or animal, prevalence of osteoporosis or osteopenia was 13-19% lower comparing extreme quartiles of vegetable intake for five AA (not glutamic acid or proline). These data provide evidence to suggest that intake of protein and several AA, including alanine and glycine, may be beneficial for bone health, independent of genetic background

The Influence of High-Impact Exercise on Cortical and Trabecular Bone Mineral Content and 3D Distribution Across the Proximal Femur in Older Men: A Randomized Controlled Unilateral Intervention.

Regular exercisers have lower fracture risk, despite modest effects of exercise on bone mineral content (BMC). Exercise may produce localized cortical and trabecular bone changes that affect bone strength independently of BMC. We previously demonstrated that brief, daily unilateral hopping exercises increased femoral neck BMC in the exercise leg versus the control leg of older men. This study evaluated the effects of these exercises on cortical and trabecular bone and its 3D distribution across the proximal femur, using clinical CT. Fifty healthy men had pelvic CT scans before and after the exercise intervention. We used hip QCT analysis to quantify BMC in traditional regions of interest and estimate biomechanical variables. Cortical bone mapping localized cortical mass surface density and endocortical trabecular density changes across each proximal femur, which involved registration to a canonical proximal femur model. Following statistical parametric mapping, we visualized and quantified statistically significant changes of variables over time in both legs, and significant differences between legs. Thirty-four men aged mean (SD) 70 (4) years exercised for 12-months, attending 92% of prescribed sessions. In traditional regions of interest, cortical and trabecular BMC increased over time in both legs. Cortical BMC at the trochanter increased more in the exercise than control leg, whereas femoral neck buckling ratio declined more in the exercise than control leg. Across the entire proximal femur, cortical mass surface density increased significantly with exercise (2.7%; p 6%) at anterior and posterior aspects of the femoral neck and anterior shaft. Endocortical trabecular density also increased (6.4%; p 12% at the anterior femoral neck, trochanter, and inferior femoral head. Odd impact exercise increased cortical mass surface density and endocortical trabecular density, at regions that may be important to structural integrity. These exercise-induced changes were localized rather than being evenly distributed across the proximal femur.This research was financially supported by a National Osteoporosis Innovative Award, Medical Research Council UK Interdisciplinary Bridging Award, and a Loughborough University Scholarship. KESP acknowledges support of the Cambridge NIHR Biomedical Research Centre.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/jbmr.249

Obesity appears to be associated with altered muscle protein synthetic and breakdown responses to increased nutrient delivery in older men, but not reduced muscle mass or contractile function.

Obesity is increasing, yet despite the necessity to maintain muscle mass and function with age, the effect of obesity on muscle protein turnover in older adults remains unknown. Eleven obese (BMI 31.9 ±1.1) and 15 healthy weight (HW; BMI 23.4 ±0.3) older men (55-75 years old) participated in a study that determined muscle protein synthesis (MPS) and leg protein breakdown (LPB) under post-absorptive (hypoinsulinaemic euglycaemic clamp) and post-prandial (hyperinsulinemic hyperaminoacidaemic euglycaemic clamp) conditions. Obesity was associated with systemic inflammation, greater leg fat mass, and patterns of mRNA expression consistent with muscle deconditioning, whilst leg lean mass, strength and work done during maximal exercise were no different. Under post-absorptive conditions, MPS and LPB were equivalent between groups, while insulin and amino acid administration increased MPS in only HW subjects and was associated with lower leg glucose disposal (LGD, 63%) in obese. Blunting of MPS in the obese was offset by an apparent decline in LPB, which was absent in HW subjects. Lower post-prandial LGD in obese subjects and blunting of MPS responses to amino acids suggests obesity in older adults is associated with diminished muscle metabolic quality. However this doesn’t appear to be associated with lower leg lean mass or strength

Consolidated health economic evaluation reporting standards (CHEERS) statement

<p>Economic evaluations of health interventions pose a particular challenge for reporting. There is also a need to consolidate and update existing guidelines and promote their use in a user friendly manner. The Consolidated Health Economic Evaluation Reporting Standards (CHEERS) statement is an attempt to consolidate and update previous health economic evaluation guidelines efforts into one current, useful reporting guidance. The primary audiences for the CHEERS statement are researchers reporting economic evaluations and the editors and peer reviewers assessing them for publication.</p> <p>The need for new reporting guidance was identified by a survey of medical editors. A list of possible items based on a systematic review was created. A two round, modified Delphi panel consisting of representatives from academia, clinical practice, industry, government, and the editorial community was conducted. Out of 44 candidate items, 24 items and accompanying recommendations were developed. The recommendations are contained in a user friendly, 24 item checklist. A copy of the statement, accompanying checklist, and this report can be found on the ISPOR Health Economic Evaluations Publication Guidelines Task Force website (www.ispor.org/TaskForces/EconomicPubGuidelines.asp).</p> <p>We hope CHEERS will lead to better reporting, and ultimately, better health decisions. To facilitate dissemination and uptake, the CHEERS statement is being co-published across 10 health economics and medical journals. We encourage other journals and groups, to endorse CHEERS. The author team plans to review the checklist for an update in five years.</p&gt