A preliminary study of the effect of closed incision management with negative pressure wound therapy over high-risk incisions

Background Certain postoperative wounds are recognised to be associated with more complications than others and may be termed high-risk. Wound healing can be particularly challenging following high-energy trauma where wound necrosis and infection rates are high. Surgical incision for joint arthrodesis can also be considered high-risk as it requires extensive and invasive surgery and postoperative distal limb swelling and wound dehiscence are common. Recent human literature has investigated the use of negative pressure wound therapy (NPWT) over high-risk closed surgical incisions and beneficial effects have been noted including decreased drainage, decreased dehiscence and decreased infection rates. In a randomised, controlled study twenty cases undergoing distal limb high-energy fracture stabilisation or arthrodesis were randomised to NPWT or control groups. All cases had a modified Robert-Jones dressing applied for 72 h postoperatively and NPWT was applied for 24 h in the NPWT group. Morphometric assessment of limb circumference was performed at six sites preoperatively, 24 and 72 h postoperatively. Wound discharge was assessed at 24 and 72 h. Postoperative analgesia protocol was standardised and a Glasgow Composite Measure Pain Score (GCPS) carried out at 24, 48 and 72 h. Complications were noted and differences between groups were assessed. Results Percentage change in limb circumference between preoperative and 24 and 72 h postoperative measurements was significantly less at all sites for the NPWT group with exception of the joint proximal to the surgical site and the centre of the operated bone at 72 h. Median discharge score was lower in the NPWT group than the control group at 24 h. No significant differences in GCPS or complication rates were noted. Conclusions Digital swelling and wound discharge were reduced when NPWT was employed for closed incision management. Larger studies are required to evaluate whether this will result in reduced discomfort and complication rates postoperatively

SHRIMP zircon U–Pb ages from coal beds across the Permian–Triassic boundary, eastern Yunnan, southwestern China

The first SHRIMP zircon U–Pb ages from coal beds close to the end-Permian mass extinction are reported from the C1 coal seam in the Yantang Mine in Laibin Town, Xuanwei County, eastern Yunnan Province. Zircons were extracted from kaolinite claystone layers, defined as tonsteins (volcanic ash deposits), in the sub-seam B1 and B3 of the coal seam C1. The U–Pb ages are 252.0 ± 2.3 Ma and 250.3 ± 2.1 Ma for the sub-seam B1 and B3, respectively. Within analytical uncertainties, these U–Pb ages include the time period of the onset of the mass extinction at 251.941 ± 0.037 Ma, which was obtained from the marine Meishan section in Zhejiang Province, ∼1600 km away from the Yantang Mine. These new ages represent not only the first and closest ages to the PTB mass extinction in terrestrial coal beds, but also ages from the nearest site to the Emeishan volcanoes investigated so far. Therefore these new data provide the most accurate stratigraphic horizon of terrestrial facies of the end-Permian extinction in South China. The Emeishan volcanoes were likely the source of volcanic ash in the coal seams at the Xuanwei County and broader areas in South China. Furthermore, the minerals and geochemistry characteristics of the C1 coal seam also implied the influences of contemporaneous volcanic activities

Palaeoceanographic controls on spatial redox distribution over the Yangtze Platform during the Ediacaran–Cambrian transition

The Ediacaran–Cambrian interval was an eventful transitional period, when dynamic interactions between the biosphere and its physical environment allowed the Earth System to cross into a new state, characterized by the presence of metazoans, more equable climates and more expansive oxygenation of the oceans. Due to the retreat of widespread sulphidic conditions, redox-sensitive trace-metals could accumulate to a greater extent in ‘black shales’ deposited in localised anoxic/euxinic environments, such as highly productive ocean margins. This study investigates the concentrations of the redox-sensitive trace-metals molybdenum and vanadium in organic-rich sedimentary rocks from seven sections of the Yangtze platform, slope and basin. Iron speciation analyses were carried out in order to distinguish oxic, anoxic-ferruginous and anoxic-sulphidic settings, while sulphur and nitrogen isotope ratios were measured to gain insight into sulphate and nitrate availability, respectively, in the context of changing redox conditions. The data herein demonstrate an overall increase in redox-sensitive trace-metal contents in black shales across the Ediacaran–Cambrian transition, but with marked temporal and spatial variability. Euxinia is evident in South China before 551 Ma in the Ediacaran, and again in the early Cambrian. However, some time-equivalent sections are not enriched in redox-sensitive trace metals, and also exhibit contrasting S-isotope and N-isotope systematics. A more complex configuration of the Yangtze Platform, for example with vast intra-shelf basins, together with changing (generally rising) eustatic sea-level may account for this variability. In this regard, it is proposed that a mid-depth sulphidic wedge, caused by nutrient upwelling over the south-east platform margins, migrated over time (but generally landward), leading to spatially variable redox conditions determined by sea-level, currents and bathymetric constraints. The changing extents of anoxia and euxinia appear to have limited the distribution of emerging Ediacaran and Cambrian ecosystems

Genetic Background Can Result in a Marked or Minimal Effect of Gene Knockout (GPR55 and CB2 Receptor) in Experimental Autoimmune Encephalomyelitis Models of Multiple Sclerosis

PMCID: PMC379391

Mapping trabecular disconnection "hotspots" in aged human spine and hip

Trabecular bone disconnection is an independent factor in age-related skeletal failure where real termini (ReTm; rare in youth) may cause weakness disproportionate to tissue loss, yet their structural contribution at vulnerable locations remains uncertain. ReTm (previously recorded at the iliac crest) were mapped in "normal" aged vertebral bodies (T11-L5 autopsy; 20 females, 10 males) and corresponding proximal femora (autopsy; 10 females). Results were compared with biomechanically failed femora from orthopaedic subjects aged >. 58. yr (osteoporosis OP, 10 females; osteoarthritis OA, 10 females). A novel direct 2D/3D histological method was applied to large, thick (300. μm) slices superficially silver-stained to separate ReTm (unstained) from apparent termini (planar artefacts, brown). Light microscope field co-ordinates enabled ReTm mapping and statistical testing relative to i) sex, ii) tissue sector and iii) slicing plane. In men ReTm populations were small and random while in women they were large and sector-specific. In vertebrae they clustered anterior/superior being rare posterior/inferior; in the femoral head they concentrated distal/superior and also near the fovea, being fewer distal/inferior. A distribution polarity was evident with 100% more ReTm observed transversely (i.e., on tensile-related cross struts) than longitudinally (i.e., on compression-related vertical struts). Their numbers rose in OP (BV/TV. . 14%), remaining polarised and sector-specific in OP only. Comparative experimentation by marrow elution of an OP animal model demonstrated "floating segments" as a possible outcome. Conclusions were supported statistically that trabecular disconnection "hotspots" at vulnerable locations are sex- and sector-specific, mainly transaxial, and subject to disease modulation

Neuroinflammation, Mast Cells, and Glia: Dangerous Liaisons

The perspective of neuroinflammation as an epiphenomenon following neuron damage is being replaced by the awareness of glia and their importance in neural functions and disorders. Systemic inflammation generates signals that communicate with the brain and leads to changes in metabolism and behavior, with microglia assuming a pro-inflammatory phenotype. Identification of potential peripheral-to-central cellular links is thus a critical step in designing effective therapeutics. Mast cells may fulfill such a role. These resident immune cells are found close to and within peripheral nerves and in brain parenchyma/meninges, where they exercise a key role in orchestrating the inflammatory process from initiation through chronic activation. Mast cells and glia engage in crosstalk that contributes to accelerate disease progression; such interactions become exaggerated with aging and increased cell sensitivity to stress. Emerging evidence for oligodendrocytes, independent of myelin and support of axonal integrity, points to their having strong immune functions, innate immune receptor expression, and production/response to chemokines and cytokines that modulate immune responses in the central nervous system while engaging in crosstalk with microglia and astrocytes. In this review, we summarize the findings related to our understanding of the biology and cellular signaling mechanisms of neuroinflammation, with emphasis on mast cell-glia interactions

Reducing the probability of false positive research findings by pre-publication validation – Experience with a large multiple sclerosis database

<p>Abstract</p> <p>Background</p> <p>Published false positive research findings are a major problem in the process of scientific discovery. There is a high rate of lack of replication of results in clinical research in general, multiple sclerosis research being no exception. Our aim was to develop and implement a policy that reduces the probability of publishing false positive research findings.</p> <p>We have assessed the utility to work with a pre-publication validation policy after several years of research in the context of a large multiple sclerosis database.</p> <p>Methods</p> <p>The large database of the Sylvia Lawry Centre for Multiple Sclerosis Research was split in two parts: one for hypothesis generation and a validation part for confirmation of selected results. We present case studies from 5 finalized projects that have used the validation policy and results from a simulation study.</p> <p>Results</p> <p>In one project, the "relapse and disability" project as described in section II (example 3), findings could not be confirmed in the validation part of the database. The simulation study showed that the percentage of false positive findings can exceed 20% depending on variable selection.</p> <p>Conclusion</p> <p>We conclude that the validation policy has prevented the publication of at least one research finding that could not be validated in an independent data set (and probably would have been a "true" false-positive finding) over the past three years, and has led to improved data analysis, statistical programming, and selection of hypotheses. The advantages outweigh the lost statistical power inherent in the process.</p

Tapping into the glial reservoir: cells committed to remaining uncommitted

The development and maturation of the oligodendrocyte requires a series of highly orchestrated events that coordinate the proliferation and differentiation of the oligodendrocyte precursor cell (OPC) as well as the spatiotemporal regulation of myelination. In recent years, widespread interest has been devoted to the therapeutic potential of adult OPCs scattered throughout the central nervous system (CNS). In this review, we highlight molecular mechanisms controlling OPC differentiation during development and the implication of these mechanisms on adult OPCs for remyelination. Cell-autonomous regulators of differentiation and the heterogeneous microenvironment of the developing and the adult CNS may provide coordinated inhibitory cues that ultimately maintain a reservoir of uncommitted glia

Mass dependent fractionation of stable chromium isotopes in mare basalts: implications for the formation and differentiation of the Moon

We present the first stable chromium isotopic data from mare basalts in order to investigate the similarity between the Moon and the Earth’s mantle. A double spike technique coupled with MC-ICP-MS measurements was used to analyse 19 mare basalts, comprising high-Ti, low-Ti and KREEP-rich varieties. Chromium isotope ratios (δ53Cr) for mare basalts are positively correlated with indices of magmatic differentiation such as Mg# and Cr concentration which suggests that Cr isotopes were fractionated during magmatic differentiation. Modelling of the results provides evidence that spinel and pyroxene are the main phases controlling the Cr isotopic composition during fractional crystallisation. The most evolved samples have the lightest isotopic compositions, complemented by cumulates that are isotopically heavy. Two hypotheses are proposed to explain this fractionation: (i) equilibrium fractionation where heavy isotopes are preferentially incorporated into the spinel lattice and (ii) a difference in isotopic composition between Cr2+ and Cr3+ in the melt. However, both processes require magmatic temperatures below 1200 °C for appreciable Cr3+ to be present at the low oxygen fugacities found in the Moon (IW −1 to −2 log units). There is no isotopic difference between the most primitive high-Ti, low-Ti and KREEP basalts, which suggest that the sources of these basalts were homogeneous in terms of stable Cr isotopes. The least differentiated sample in our sample set is the low-Ti basalt 12016, characterised by a Cr isotopic composition of −0.222 ± 0.025‰, which is within error of the current BSE value (−0.124 ± 0.101‰). The similarity between the mantles of the Moon and Earth is consistent with a terrestrial origin for a major fraction of the lunar Cr. This similarity also suggests that Cr isotopes were not fractionated by core formation on the Moon