Extracellular ATP released by osteoblasts is a key local inhibitor of bone mineralisation

Previous studies have shown that exogenous ATP (>1µM) prevents bone formation in vitro by blocking mineralisation of the collagenous matrix. This effect is thought to be mediated via both P2 receptor-dependent pathways and a receptor-independent mechanism (hydrolysis of ATP to produce the mineralisation inhibitor pyrophosphate, PPi). Osteoblasts are also known to release ATP constitutively. To determine whether this endogenous ATP might exert significant biological effects, bone-forming primary rat osteoblasts were cultured with 0.5-2.5U/ml apyrase (which sequentially hydrolyses ATP to ADP to AMP + 2Pi). Addition of 0.5U/ml apyrase to osteoblast culture medium degraded extracellular ATP to <1% of control levels within 2 minutes; continuous exposure to apyrase maintained this inhibition for up to 14 days. Apyrase treatment for the first 72 hours of culture caused small decreases (≤25%) in osteoblast number, suggesting a role for endogenous ATP in stimulating cell proliferation. Continuous apyrase treatment for 14 days (≥0.5U/ml) increased mineralisation of bone nodules by up to 3-fold. Increases in bone mineralisation were also seen when osteoblasts were cultured with the ATP release inhibitors, NEM and brefeldin A, as well as with P2X1 and P2X7 receptor antagonists. Apyrase decreased alkaline phosphatase (TNAP) activity by up to 60%, whilst increasing the activity of the PPi-generating ecto-nucleotide pyrophosphatase/phosphodiesterases (NPPs) up to 2.7-fold. Both collagen production and adipocyte formation were unaffected. These data suggest that nucleotides released by osteoblasts in bone could act locally, via multiple mechanisms, to limit mineralisation

CtGEM typing: Discrimination of Chlamydia trachomatis ocular and urogenital strains and major evolutionary lineages by high resolution melting analysis of two amplified DNA fragments

© 2018 Giffard et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Chlamydia trachomatis infects the urogenital tract (UGT) and eyes. Anatomical tropism is correlated with variation in the major outer membrane protein encoded by ompA. Strains possessing the ocular ompA variants A, B, Ba and C are typically found within the phyloge-netically coherent “classical ocular lineage”. However, variants B, Ba and C have also been found within three distinct strains in Australia, all associated with ocular disease in children and outside the classical ocular lineage. CtGEM genotyping is a method for detecting and discriminating ocular strains and also the major phylogenetic lineages. The rationale was facilitation of surveillance to inform responses to C. trachomatis detection in UGT specimens from young children. CtGEM typing is based on high resolution melting analysis (HRMA) of two PCR amplified fragments with high combinatorial resolving power, as defined by computerised comparison of 65 whole genomes. One fragment is from the hypothetical gene defined by Jali-1891 in the C. trachomatis B_Jali20 genome, while the other is from ompA. Twenty combinatorial CtGEM types have been shown to exist, and these encompass unique genotypes for all known ocular strains, and also delineate the TI and T2 major phylogenetic lineages, identify LGV strains and provide additional resolution beyond this. CtGEM typing and Sanger sequencing were compared with 42 C. trachomatis positive clinical specimens, and there were no disjunctions. CtGEM typing is a highly efficient method designed and tested using large scale comparative genomics. It divides C. trachomatis into clinically and biologically meaningful groups, and may have broad application in surveillance

The Evolutionary Pathway to Obligate Scavenging in Gyps Vultures

The evolutionary pathway to obligate scavenging in Gyps vultures remains unclear. We propose that communal roosting plays a central role in setting up the information transfer network critical for obligate scavengers in ephemeral environments and that the formation of a flotilla-like foraging group is a likely strategy for foraging Gyps vultures. Using a spatial, individual-based, optimisation model we find that the communal roost is critical for establishing the information network that enables information transfer owing to the spatial-concentration of foragers close to the roost. There is also strong selection pressure for grouping behaviour owing to the importance of maintaining network integrity and hence information transfer during foraging. We present a simple mechanism for grouping, common in many animal species, which has the added implication that it negates the requirement for roost-centric information transfer. The formation of a flotilla-like foraging group also improves foraging efficiency through the reduction of overlapping search paths. Finally, we highlight the importance of consideration of information transfer mechanisms in order to maximise the success of vulture reintroduction programmes

A retrospective and agenda for future research on Chinese outward foreign direct investment

Our original paper “The determinants of Chinese Outward Foreign Direct Investment” was the first theoretically based empirical analysis of the phenomenon. It utilised internalisation theory to show that Chinese state-owned firms reacted to home country market imperfections to surmount barriers to foreign entry arising from naivety and the lack of obvious ownership advantages, leveraging institutional factors including favourable policy stimuli. This special theory explained outward foreign direct investment (OFDI) but provided surprises. These included the apparent appetite for risk evinced by these early investors, causing us to conjecture that domestic market imperfections, particularly in the domestic capital market, might be responsible. The article stimulated a massive subsequent, largely successful, research effort on emerging country multinationals. In this Retrospective article we review some of the main strands of research that ensued, for the insight they offer for the theme of our commentary. Our theme is that theoretical development can only come through embracing yet more challenging, different, and new contexts, and we make suggestions for future research directions

Chromosomal instability and lack of cyclin E regulation in hCdc4 mutant human breast cancer cells

INTRODUCTION: Cyclin E, a G(1 )cyclin essential for G(1)–S phase transition, is known to have a profound effect on tumorigenesis. Elevated levels of cyclin E have been associated with breast cancer, and chromosomal instability observed in breast cancer is suggested to be associated with constitutive expression of cyclin E. It was previously demonstrated that SUM149PT human breast cancer cells show very high levels of cyclin E expression by western analysis and that they express a nonfunctional cyclin E ubiquitin ligase due to a mutation in the F-box protein hCdc4. METHODS: We examined cyclin E expression in both MCF10A and SUM149PT cells using western blot analysis and flow cytometry. Immunofluorescence was utilized for the localization of cyclin E in both normal and breast cancer cells. In addition, array comparative genomic hybridization analysis was performed to compare chromosome copy number alterations with levels of cyclin E expression among a panel of breast cancer cell lines. RESULTS: SUM149PT cells overexpress cyclin E on a cell per cell basis for the duration of the cell cycle. High cyclin E levels are maintained throughout the S phase, and SUM149PT cells exhibit an S phase delay or arrest probably due to cyclin E overexpression. In addition, comparative genomic hybridization indicated that SUM149PT cells exhibit many chromosome copy number alterations, which may reflect prior or ongoing genomic instability. However, no direct correlation was observed between cyclin E levels and genomic copy number alteration in a panel of human breast cancer cell lines. CONCLUSIONS: Cyclin E is overexpressed at high levels throughout the cell cycle in SUM149PT cells, which is in stark contrast to cyclin E degradation observed in the mid to late S phase of normal cells. SUM149PT cells are unable to regulate cyclin E and also exhibit many copy number alterations. However, there was a lack of direct correlation between cyclin E overexpression and chromosomal instability across a panel of other breast cancer cell lines examined

Phenotypic redshifts with self-organizing maps: A novel method to characterize redshift distributions of source galaxies for weak lensing

Wide-field imaging surveys such as the Dark Energy Survey (DES) rely on coarse measurements of spectral energy distributions in a few filters to estimate the redshift distribution of source galaxies. In this regime, sample variance, shot noise, and selection effects limit the attainable accuracy of redshift calibration and thus of cosmological constraints. We present a new method to combine wide-field, few-filter measurements with catalogs from deep fields with additional filters and sufficiently low photometric noise to break degeneracies in photometric redshifts. The multi-band deep field is used as an intermediary between wide-field observations and accurate redshifts, greatly reducing sample variance, shot noise, and selection effects. Our implementation of the method uses self-organizing maps to group galaxies into phenotypes based on their observed fluxes, and is tested using a mock DES catalog created from N-body simulations. It yields a typical uncertainty on the mean redshift in each of five tomographic bins for an idealized simulation of the DES Year 3 weak-lensing tomographic analysis of $\sigma_{\Delta z} = 0.007$, which is a 60% improvement compared to the Year 1 analysis. Although the implementation of the method is tailored to DES, its formalism can be applied to other large photometric surveys with a similar observing strategy.Comment: 24 pages, 11 figures; matches version accepted to MNRA

Mind your step: the effects of mobile phone use on gaze behavior in stair climbing

Stair walking is a hazardous activity and a common cause of fatal and non-fatal falls. Previous studies have assessed the role of eye movements in stair walking by asking people to repeatedly go up and down stairs in quiet and controlled conditions, while the role of peripheral vision was examined by giving participants specific fixation instructions or working memory tasks. We here extend this research to stair walking in a natural environment with other people present on the stairs and a now common secondary task: Using one's mobile phone. Results show that using the mobile phone strongly draws one's attention away from the stairs, but that the distribution of gaze locations away from the phone is little influenced by using one's phone. Phone use also increased the time needed to walk the stairs, but handrail use remained low. These results indicate that limited foveal vision suffices for adequate stair walking in normal environments, but that mobile phone use has a strong influence on attention, which may pose problems when unexpected obstacles are encountered

Using a Powered Bone Marrow Biopsy System Results in Shorter Procedures, Causes Less Residual Pain to Adult Patients, and Yields Larger Specimens

<p>Abstract</p> <p>Background</p> <p>In recent years, a battery-powered bone marrow biopsy system was developed and cleared by the U.S. Food and Drug Administration to allow health care providers to access the bone marrow space quickly and efficiently. A multicenter randomized clinical trial was designed for adult patients to determine if the powered device had advantages over traditional manually-inserted needles in regard to length of procedure, patient pain, complications, user satisfaction, and pathological analysis of the specimens.</p> <p>Methods</p> <p>Adult patients requiring marrow sampling procedures were randomized for a Manual or Powered device. Visual Analog Scale (VAS) pain scores were captured immediately following the procedure and 1 and 7 days later. Procedure time was measured and core specimens were submitted to pathology for grading.</p> <p>Results</p> <p>Ten sites enrolled 102 patients into the study (Powered, n = 52; Manual, n = 50). Mean VAS scores for overall procedural pain were not significantly different between the arms (3.8 ± 2.8 for Powered, 3.5 ± 2.3 for Manual [p = 0.623]). A day later, more patients who underwent the Powered procedure were pain-free (67%) than those patients in the Manual group (33%; p = 0.003). One week later, there was no difference (83% for Powered patients; 76% for Manual patients.) Mean procedure time was 102.1 ± 86.4 seconds for the Powered group and 203.1 ± 149.5 seconds for the Manual group (p < 0.001). Pathology assessment was similar in specimen quality, but there was a significant difference in the specimen volume between the devices (Powered: 36.8 ± 21.2 mm³; Manual: 20.4 ± 9.0 mm³; p = 0.039). Two non-serious complications were experienced during Powered procedures (4%); but none during Manual procedures (p = 0.495).</p> <p>Conclusions</p> <p>The results of this first trial provide evidence that the Powered device delivers larger-volume bone marrow specimens for pathology evaluation. In addition, bone marrow specimens were secured more rapidly and subjects experienced less intermediate term pain when the Powered device was employed. Further study is needed to determine if clinicians more experienced with the Powered device will be able to use it in a manner that significantly reduces needle insertion pain; and to compare a larger sample of pathology specimens obtained using the Powered device to those obtained using traditional manual biopsy needles.</p

A multifault earthquake threat for the Seattle metropolitan region revealed by mass tree mortality

This is the final version. Available on open access from the American Association for the Advancement of Science via the DOI in this recordData and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and Supplementary Materials. The MacBlo, Price Lake, Hamma Hamma, Lake Washington, West Point log, Lake Sammamish, and Dry Bed Lake tree-ring measurement data will be available upon publication through the U.S. National Oceanic and Atmospheric Administration World Data Service for Paleoclimatology International Tree-Ring Databank (www.ncei.noaa.gov/products/paleoclimatology/tree-ring) as datasets CAN382 and WA155 to WA160. All radiocarbon data are provided in table S2.Compound earthquakes involving simultaneous ruptures along multiple faults often define a region’s upper threshold of maximum magnitude. Yet, the potential for linked faulting remains poorly understood given the infrequency of these events in the historic era. Geological records provide longer perspectives, although temporal uncertainties are too broad to clearly pinpoint single multifault events. Here, we use dendrochronological dating and a cosmogenic radiation pulse to constrain the death dates of earthquake-killed trees along two adjacent fault zones near Seattle, Washington to within a 6-month period between the 923 and 924 CE growing seasons. Our narrow constraints conclusively show linked rupturing that occurred either as a single composite earthquake of estimated magnitude 7.8 or as a closely spaced double earthquake sequence with estimated magnitudes of 7.5 and 7.3. These scenarios, which are not recognized in current hazard models, increase the maximum earthquake size needed for seismic preparedness and engineering design within the Puget Sound region of >4 million residents.U.S. Geological Surve