Thiol isomerases negatively regulate the cellular shedding activity of ADAM17

ADAM17 (where ADAM is 'a disintegrin and metalloproteinase') can rapidly modulate cell-surface signalling events by the proteolytic release of soluble forms of proligands for cellular receptors. Many regulatory pathways affect the ADAM17 sheddase activity, but the mechanisms for the activation are still not clear. We have utilized a cell-based ADAM17 assay to show that thiol isomerases, specifically PDI (protein disulfide isomerase), could be responsible for maintaining ADAM17 in an inactive form. Down-regulation of thiol isomerases, by changes in the redox environment (for instance as elicited by phorbol ester modulation of mitochondrial reactive oxygen species) markedly enhanced ADAM17 activation. On the basis of ELISA binding studies with novel fragment antibodies against ADAM17 we propose that isomerization of the disulfide bonds in ADAM17, and the subsequent conformational changes, form the basis for the modulation of ADAM17 activity. The shuffling of disulfide bond patterns in ADAMs has been suggested by a number of recent adamalysin crystal structures, with distinct disulfide bond patterns altering the relative orientations of the domains. Such a mechanism is rapid and reversible, and the role of thiol isomerases should be investigated further as a potential factor in the redox regulation of ADAM17.

Localization of polymorphic N-acetyltransferase (NAT2) in tissues of inbred mice

Like humans, mice exhibit polymorphism in the N-acetylation of aromatic amines, many of which are toxic and/or carcinogenic. Mice have three N-acetyltransferase (Nat) genes, Nat1, Nat2 and Nat3, and Nat2 is known to be polymorphic. There is a dramatic difference in the acetylation of NAT2 substrates by blood from fast (C57BL/6J) compared with slow acetylator (A/J) mice. However, the acetylation of these substrates by liver cytosols from the two strains is very similar. In order to determine whether the expression of the NAT2 protein corresponded with the activities measured, a polyclonal antipeptide antisera was raised against the C-terminal decapeptide of NAT2 and characterized using recombinant murine NAT2 antigen. Enzyme-linked immunosorbent assays (ELISAs) demonstrated that the anti-NAT2 antiserum bound in a concentration-dependent fashion to recombinant NAT2. Immunochemical analysis of mouse liver cytosols from C57BL/6J or A/J livers indicated that the level of NAT2 protein expressed in the two strains was similar. Immunohistochemical staining of C57BL/6J liver with anti-NAT2 antiserum showed that NAT2 was expressed in hepatocytes throughout the liver although the intensity of staining in the perivenous (centrilobular) region was higher than that in the periportal region. NAT2 was also detected in epithelial cells in the lung, kidney, bladder, small intestine and skin as well as in erythrocytes and lymphocytes in the spleen and hair follicles and sebaceous glands in the skin. Characterization of the distribution of NAT2 will be of value in elucidating the role of polymorphic N-acetylation in protecting the organism from environmental insults as well as in endogenous metabolism.

Whole Genome Sequencing Reveals Local Transmission Patterns of Mycobacterium bovis in Sympatric Cattle and Badger Populations

Whole genome sequencing (WGS) technology holds great promise as a tool for the forensic epidemiology of bacterial pathogens. It is likely to be particularly useful for studying the transmission dynamics of an observed epidemic involving a largely unsampled 'reservoir' host, as for bovine tuberculosis (bTB) in British and Irish cattle and badgers. BTB is caused by Mycobacterium bovis, a member of the M. tuberculosis complex that also includes the aetiological agent for human TB. In this study, we identified a spatio-temporally linked group of 26 cattle and 4 badgers infected with the same Variable Number Tandem Repeat (VNTR) type of M. bovis. Single-nucleotide polymorphisms (SNPs) between sequences identified differences that were consistent with bacterial lineages being persistent on or near farms for several years, despite multiple clear whole herd tests in the interim. Comparing WGS data to mathematical models showed good correlations between genetic divergence and spatial distance, but poor correspondence to the network of cattle movements or within-herd contacts. Badger isolates showed between zero and four SNP differences from the nearest cattle isolate, providing evidence for recent transmissions between the two hosts. This is the first direct genetic evidence of M. bovis persistence on farms over multiple outbreaks with a continued, ongoing interaction with local badgers. However, despite unprecedented resolution, directionality of transmission cannot be inferred at this stage. Despite the often notoriously long timescales between time of infection and time of sampling for TB, our results suggest that WGS data alone can provide insights into TB epidemiology even where detailed contact data are not available, and that more extensive sampling and analysis will allow for quantification of the extent and direction of transmission between cattle and badgers. © 2012 Biek et al.

Understanding aerospace composite components' supply chain carbon emissions

This paper examines a large structural component and its supply chain. The component is representative of that used in the production of civil transport aircraft and is manufactured from carbon fibre epoxy resin prepreg, using traditional hand layup and autoclave cure. Life cycle assessment (LCA) is used to predict the component’s production carbon emissions. The results determine the distribution of carbon emissions within the supply chain, identifying the dominant production processes as carbon fibre manufacture and composite part manufacture. The elevated temperature processes of material and part creation, and the associated electricity usage, have a significant impact on the overall production emissions footprint. The paper also demonstrates the calculation of emissions footprint sensitivity to the geographic location and associated energy sources of the supply chain. The results verify that the proposed methodology is capable of quantitatively linking component and supply chain specifics to manufacturing processes and thus identifying the design drivers for carbon emissions in the manufacturing life of the component.

Decentralized Computation of Pareto Optimal Pure Nash Equilibria of Boolean Games with Privacy Concerns

In Boolean games, agents try to reach a goal formulated as a Boolean formula. These games are attractive because of their compact representations. However, few methods are available to compute the solutions and they are either limited or do not take privacy or communication concerns into account. In this paper we propose the use of an algorithm related to reinforcement learning to address this problem. Our method is decentralized in the sense that agents try to achieve their goals without knowledge of the other agents’ goals. We prove that this is a sound method to compute a Pareto optimal pure Nash equilibrium for an interesting class of Boolean games. Experimental results are used to investigate the performance of the algorithm.

Neurology assessment by objective structured video examination (OSVE)

Summary
Background
The ability to carry out a neurological examination and make an appropriate differential diagnosis is one of the mainstays of our final Bachelor of Medicine (MB) exam; however, with the introduction of objective structured clinical examinations (OSCEs) it has become impossible to arrange for adequate numbers of suitable real patients to participate in the exam.

Context
It is vital that newly qualified doctors can perform a basic neurological examination, interpret the physical signs and formulate a differential diagnosis.

It is vital that newly qualified doctors can perform a basic neurological examination

Innovation
Since 2010 we have introduced an objective structured video examination (OSVE) of a neurological examination of a real patient as part of our final MB OSCE exam. The students view clips of parts of the examination process. They answer questions on the signs that are demonstrated and formulate a differential diagnosis.

Implications
This type of station is logistically a lot easier to organise than a large number of real patients at different examination sites. The featured patients have clearly demonstrated signs and, as every student sees the same patient, are perfectly standardised. It is highly acceptable to examiners and performed well as an assessment tool. There are, however, certain drawbacks in that we are not examining the student's examination technique or their interaction with the patient. Also, certain signs, in particular the assessment of muscle tone and power, are more difficult for a student to estimate in this situation

Tumor suppressor Ras-association domain family 1 isoform A is a novel regulator of cardiac hypertrophy

BACKGROUND: Ras signaling regulates a number of important processes in the heart, including cell growth and hypertrophy. Although it is known that defective Ras signaling is associated with Noonan, Costello, and other syndromes that are characterized by tumor formation and cardiac hypertrophy, little is known about factors that may control it. Here we investigate the role of Ras effector Ras-association domain family 1 isoform A (RASSF1A) in regulating myocardial hypertrophy.

METHODS AND RESULTS: A significant downregulation of RASSF1A expression was observed in hypertrophic mouse hearts, as well as in failing human hearts. To further investigate the role of RASSF1A in cardiac (patho)physiology, we used RASSF1A knock-out (RASSF1A(-)(/)(-)) mice and neonatal rat cardiomyocytes with adenoviral overexpression of RASSF1A. Ablation of RASSF1A in mice significantly enhanced the hypertrophic response to transverse aortic constriction (64.2% increase in heart weight/body weight ratio in RASSF1A(-)(/)(-) mice compared with 32.4% in wild type). Consistent with the in vivo data, overexpression of RASSF1A in cardiomyocytes markedly reduced the cellular hypertrophic response to phenylephrine stimulation. Analysis of molecular signaling events in isolated cardiomyocytes indicated that RASSF1A inhibited extracellular regulated kinase 1/2 activation, likely by blocking the binding of Raf1 to active Ras.

CONCLUSIONS: Our data establish RASSF1A as a novel inhibitor of cardiac hypertrophy by modulating the extracellular regulated kinase 1/2 pathway.

Imaging and radiation effects of gold nanoparticles in tumour cells

Gold nanoparticle radiosensitization represents a novel technique in enhancement of ionising radiation dose and its effect on biological systems. Variation between theoretical predictions and experimental measurement is significant enough that the mechanism leading to an increase in cell killing and DNA damage is still not clear. We present the first experimental results that take into account both the measured biodistribution of gold nanoparticles at the cellular level and the range of the product electrons responsible for energy deposition. Combining synchrotron-generated monoenergetic X-rays, intracellular gold particle imaging and DNA damage assays, has enabled a DNA damage model to be generated that includes the production of intermediate electrons. We can therefore show for the first time good agreement between the prediction of biological outcomes from both the Local Effect Model and a DNA damage model with experimentally observed cell killing and DNA damage induction via the combination of X-rays and GNPs. However, the requirement of two distinct models as indicated by this mechanistic study, one for short-term DNA damage and another for cell survival, indicates that, at least for nanoparticle enhancement, it is not safe to equate the lethal lesions invoked in the local effect model with DNA damage events.

Factors influencing the output of rural cataract surgical facilities in China: the SHARP study

Purpose: To identify factors associated prospectively with increased cataract surgical rate (CSR) in rural Chinese hospitals.

Methods: Annual cataract surgical output was obtained at baseline and 24 months later from operating room records at 42 rural, county-level hospitals. Total local CSR (cases/million population/y), and proportion of CSR from hospital and local competitors were calculated from government records. Hospital administrators completed questionnaires providing demographic and professional information, and annual clinic and outreach screening volume. Independent cataract surgeons provided clinical information and videotapes of cases for grading by two masked experts using the Ophthalmology Surgical Competency Assessment Rubric (OSCAR). Uncorrected vision was recorded for 10 consecutive cataract cases at each facility, and 10 randomly-identified patients completed hospital satisfaction questionnaires. Total value of international nongovernmental development organization (INGDO) investment in the previous three years and demographic information on hospital catchment areas were obtained. Main outcome was 2-year percentage change in hospital CSR.

Results: Among the 42 hospitals (median catchment population 530,000, median hospital CSR 643), 78.6% (33/42) were receiving INGDO support. Median change in hospital CSR (interquartile range) was 33.3% (-6.25%, 72.3%). Predictors of greater increase in CSR included higher INGDO investment (P = 0.02, simple model), reducing patient dissatisfaction (P = 0.03, simple model), and more outreach patient screening (P = 0.002, simple and multiple model).

Conclusions: Outreach cataract screening was the strongest predictor of increased surgical output. Government and INGDO investment in screening may be most likely to enhance output of county hospitals, a major goal of China's Blindness Prevention Plan.

Outcomes and projected impact on vision restoration of the China million cataract surgeries program

Purpose: The recently completed Chinese "Million Cataract Surgeries Program" (MCSP) is among the largest such campaigns ever, providing 1.05 million operations. We report MCSP outcomes for the first time, in Jiangxi, the province with the greatest program output. Methods: Ten county hospitals participating in MCSP were selected in Jiangxi (range of gross domestic product per capita US$743-2998). Each hospital sought to enroll 75 consecutive MCSP patients aged ≥50 years. Data recorded included type of cataract procedure, bilateral uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), and refractive error pre- and ≥50 days postoperatively. Results: Among 715 patients (mean age 72.3±9.1 years, 55.5% female), preoperative UCVA was <3/60 (legally blind) bilaterally in 13.3% and unilaterally in the operated eye in 50.9%. No subjects had UCVA >6/18 preoperatively. Small incision cataract surgery was performed in 92.3% patients. Among 662 patients (92.6%) completing follow-up was ≥ 40 days after surgery, BCVA was ≥6/18 in 80.1%, UCVA was ≥6/18 in 57.1% and UCVA was <3/60 in 2.1%. Older age (p<0.001), female sex (p=0.04), worse refractive error (p=0.02) and presence of intra- (p=0.002) and postoperative surgical complications (p<0.001), were independently associated with worse postoperative UCVA. Based on these results, the MCSP cured an estimated 124,950 cases (13.3%×[100-2.1%]×1.05 million) of bilateral and 502,500 (50.9%×[100-2.1%]×1.05 million) of unilateral blindness. Conclusions: Due to relatively good outcomes and the large number of surgeries performed on blind persons, the sight-restoring impact of the MCSP was probably substantial. © Informa Healthcare USA, Inc.

Hearing the voices of kinship foster carers in Northern Ireland: An inquiry into characteristics, needs and experiences

This study describes an investigation into the characteristics, needs and experiences of kinship foster carers in Northern Ireland. By adopting a mixed-methods approach with 54 carers, a number of salient themes was captured. The respondents were predominantly grandparents who experienced a significant incidence of health-related issues. The cohort also endured high levels of stress, particularly at the beginning stage of the foster placement. Consequently, their need for practical, emotional and respite support was most evident. In terms of the children for whom they cared, many required help at school, and some presented with challenging emotions and behaviours. Overall, these findings emphasised the importance of relationship-based social work and demonstration of accurate empathy to the carer.