MicroRNA-9 represses sirtuin 1 (SIRT1) in human keratinocytes

The protein deacetylase sirtuin 1 (SIRT1) is an established regulator of diverse physiological processes and one of several promising targets for pharmacologic modulation of ageing and longevity. In normal human keratinocytes, SIRT1 has been shown to inhibit proliferation and promote differentiation. MicroRNAs (miRNAs), small non-coding RNA molecules that negatively regulate gene expression, have been shown to regulate SIRT1 expression in several cell types. Using western blotting, we show that miR-9 represses SIRT1 expression in the HaCaT human keratinocytes. The attenuation of SIRT1 levels in response to ectopic miR-9 occurred in a dose-dependent manner. As miR-9 expression is known to be under epigenetic control, the effect of the histone deacetylase (HDAC) inhibitor trichostatin A (TSA) was examined. Levels of mature miR-9 increased 8-fold following TSA treatment of HaCaT keratinocytes. Expression of the primary transcripts from which miR-9 is derived was also raised in HaCaT keratinocytes exposed to TSA, with a 7-fold elevation of pri-miR-9-1 and 4-fold increase of pri-miR-3. In contrast the DNA methyl transferase inhibitor 5-deoxy-azacytidine (DAC) had little effect on miR-9 or primary miR-9 expression. Together, our findings point to a role for chromatin remodelling in regulating miR-9 levels in human keratinocytes and in turn modulation of SIRT1 expression by miR-9

The pattern of childhood in the western Cape

An analysis of poisoning cases treated at the Red Cross War Memorial Children's Hospital dUring 1987 and of calls received on the poisons line is presented. Treatment of 1116 children was undertaken and 922 telephone calls were logged. Of the patients treated, 60% had ingested a drug and 30% had drunk paraffin. The high prevalence of paraffin poisoning in the western Cape is examined. Constant vigilance must be maintained if childhood poisoning is to be prevented.S Afr Med J 1990; 78: 22-2

Body composition in Nepalese children using isotope dilution: the production of ethnic-specific calibration equations and an exploration of methodological issues.

Background. Body composition is important as a marker of both current and future health. Bioelectrical impedance (BIA) is a simple and accurate method for estimating body composition, but requires population-specific calibration equations. Objectives. (1) To generate population specific calibration equations to predict lean mass (LM) from BIA in Nepalese children aged 7-9 years. (2) To explore methodological changes that may extend the range and improve accuracy. Methods. BIA measurements were obtained from 102 Nepalese children (52 girls) using the Tanita BC-418. Isotope dilution with deuterium oxide was used to measure total body water and to estimate LM. Prediction equations for estimating LM from BIA data were developed using linear regression, and estimates were compared with those obtained from the Tanita system. We assessed the effects of flexing the arms of children to extend the range of coverage towards lower weights. We also estimated potential error if the number of children included in the study was reduced. Findings. Prediction equations were generated, incorporating height, impedance index, weight and sex as predictors (R (2) 93%). The Tanita system tended to under-estimate LM, with a mean error of 2.2%, but extending up to 25.8%. Flexing the arms to 90° increased the lower weight range, but produced a small error that was not significant when applied to children <16 kg (p 0.42). Reducing the number of children increased the error at the tails of the weight distribution. Conclusions. Population-specific isotope calibration of BIA for Nepalese children has high accuracy. Arm position is important and can be used to extend the range of low weight covered. Smaller samples reduce resource requirements, but leads to large errors at the tails of the weight distribution

Simulation for communication skills training in medical students: Protocol for a systematic scoping review

Empirical research has produced inconclusive, and occasionally contradictory, evidence relating to the extent to which improvements in medical communication skills taught through simulation can be measured. This is further limited by the wide range of designs and outcome collection methods that studies employ and does not allow for data comparability or meta-analysis. The proposed scoping review aims to systematically map and comprehensively explore the extent, range and nature of research activity on the use of simulation for communication skills training in medical education. Comprehensive literature searches in MEDLINE, EMBASE, Scopus and Web of Science will be performed and data will be reported using quantitative (simple numeric counts) and qualitative (thematic synthesis) analyses

Development of an In Silico Profiler for Respiratory Sensitisation

In this article, we outline work that led the QSAR and Molecular Modelling Group at Liverpool John Moores University to be jointly awarded the 2013 Lush Science Prize. Our research focuses around the development of in silico profilers for category formation within the Adverse Outcome Pathway paradigm. The development of a well-defined chemical category allows toxicity to be predicted via read-across. This is the central approach used by the OECD QSAR Toolbox. The specific work for which we were awarded the Lush Prize was for the development of such an in silico profiler for respiratory sensitisation. The profiler was developed by an analysis of the mechanistic chemistry associated with covalent bond formation in the lung. The data analysed were collated from clinical reports of occupational asthma in humans. The impact of the development of in silico profilers on the Three Rs is also discussed

The changing trends of childhood poisoning at a tertiary children’s hospital in South Africa

Context. Information on childhood poisoning in the developingworld, including South Africa, is scarce, despite its contribution tomorbidity and mortality.Objective. We describe the profile of children with exposuresand poisonings presenting to Red Cross War Memorial Children&rsquo;sHospital (RCWMCH) in Cape Town, South Africa, from 2003 to2008 and compare the trends of causative agents over the past twodecades.Methods. Cases were identified by review of the RCWMCH caserecords.Results. Of the total incidents (N=2 872), paraffin (kerosene)was the commonest agent (n=692, 24%) with 124 poisoningsincluding two deaths. Drugs were the most common toxin group(n=988, 34%), including 139 single-drug poisonings with 5deaths; 4 associated with traditional medicine use. Householdcleaning product incidents (n=302, 10%) resulted in 29 singleproductpoisonings with no deaths. Pesticide incidents (n=311,10%) included 6 deaths; 203 (65%) incidents were due toorganophosphates or carbamates. The suburban distribution ofthe main toxin groups varied. Comparing 1987 and 2008, thenumber of incidents decreased from 1 116 to 447; drug and paraffinincidents decreased respectively (from 673 to 150 and from 332 to87), household cleaning products and cosmetics increased (21 to69) and pesticide incidents increased (7 to 69).Conclusion. Despite a decrease in the overall number of incidentsover two decades at RCWMCH, paraffin and drugs remainthe principal agents responsible for paediatric exposures andpoisonings, with increasing incidents due to household cleaningproducts and pesticides. Identification of these toxin groups comingfrom specific suburbs allows for targeted prevention initiatives

A machine learning‑based image segmentation method to quantify in vitro osteoclast culture endpoints

Quantification of in vitro osteoclast cultures (e.g. cell number) often relies on manual counting methods. These approaches are labour intensive, time consuming and result in substantial inter- and intra-user variability. This study aimed to develop and validate an automated workflow to robustly quantify in vitro osteoclast cultures. Using ilastik, a machine learning-based image analysis software, images of tartrate resistant acid phosphatase-stained mouse osteoclasts cultured on dentine discs were used to train the ilastik-based algorithm. Assessment of algorithm training showed that osteoclast numbers strongly correlated between manual- and automatically quantified values (r = 0.87). Osteoclasts were consistently faithfully segmented by the model when visually compared to the original reflective light images. The ability of this method to detect changes in osteoclast number in response to different treatments was validated using zoledronate, ticagrelor, and co-culture with MCF7 breast cancer cells. Manual and automated counting methods detected a 70% reduction (p < 0.05) in osteoclast number, when cultured with 10 nM zoledronate and a dose-dependent decrease with 1-10 μM ticagrelor (p < 0.05). Co-culture with MCF7 cells increased osteoclast number by ≥ 50% irrespective of quantification method. Overall, an automated image segmentation and analysis workflow, which consistently and sensitively identified in vitro osteoclasts, was developed. Advantages of this workflow are (1) significantly reduction in user variability of endpoint measurements (93%) and analysis time (80%); (2) detection of osteoclasts cultured on different substrates from different species; and (3) easy to use and freely available to use along with tutorial resources

Improving Phrap-Based Assembly of the Rat Using “Reliable” Overlaps

The assembly methods used for whole-genome shotgun (WGS) data have a major impact on the quality of resulting draft genomes. We present a novel algorithm to generate a set of “reliable” overlaps based on identifying repeat k-mers. To demonstrate the benefits of using reliable overlaps, we have created a version of the Phrap assembly program that uses only overlaps from a specific list. We call this version PhrapUMD. Integrating PhrapUMD and our “reliable-overlap” algorithm with the Baylor College of Medicine assembler, Atlas, we assemble the BACs from the Rattus norvegicus genome project. Starting with the same data as the Nov. 2002 Atlas assembly, we compare our results and the Atlas assembly to the 4.3 Mb of rat sequence in the 21 BACs that have been finished. Our version of the draft assembly of the 21 BACs increases the coverage of finished sequence from 93.4% to 96.3%, while simultaneously reducing the base error rate from 4.5 to 1.1 errors per 10,000 bases. There are a number of ways of assessing the relative merits of assemblies when the finished sequence is available. If one views the overall quality of an assembly as proportional to the inverse of the product of the error rate and sequence missed, then the assembly presented here is seven times better. The UMD Overlapper with options for reliable overlaps is available from the authors at http://www.genome.umd.edu. We also provide the changes to the Phrap source code enabling it to use only the reliable overlaps

Signatures of Reductive Magnetic Mineral Diagenesis From Unmixing of First-Order Reversal Curves

Diagenetic alteration of magnetic minerals occurs in all sedimentary environments and tends to be severe in reducing environments. Magnetic minerals provide useful information about sedimentary diagenetic processes, which makes it valuable to use magnetic properties to identify the diagenetic environment in which the magnetic minerals occur and to inform interpretations of paleomagnetic recording or environmental processes. We use a newly developed first-order reversal curve (FORC) unmixing method on well-studied samples to illustrate how magnetic properties can be used to assess diagenetic processes in reducing sedimentary environments. From our analysis of multiple data sets, consistent magnetic components are identified for each stage of reductive diagenesis. Relatively unaltered detrital and biogenic magnetic mineral assemblages in surficial oxic to manganous diagenetic environments undergo progressive dissolution with burial into ferruginous and sulfidic environments, and largely disappear at the sulfate-methane transition (SMT). Below the SMT, a weak superparamagnetic to largely non-interacting stable single domain (SD) greigite component is observed in all studied data sets. Moderately interacting stable SD authigenic pyrrhotite and strongly interacting stable SD greigite are observed commonly in methanic environments. Recognition of these characteristic magnetic components enables identification of key diagenetic processes and should help to constrain interpretation of magnetic mineral assemblages in future studies. A key question for future studies concerns whether stable SD greigite forms in the sulfidic or methanic zones, where formation in deeper methanic sediments will cause greater delays in paleomagnetic signal recording. Authigenic pyrrhotite forms in methanic environments, so it will usually record a delayed paleomagnetic signal.European Research Council (320750) Australian Research Council (DP160100805