Mutational analysis of a heterogeneous nuclear ribonucleoprotein A2 response element for RNA trafficking

Cytoplasmic transport and localization of mRNA has been reported for a range of oocytes and somatic cells. The heterogeneous nuclear ribonucleoprotein (hnRNP) A2 response element (A2RE) is a 21-nucleotide segment of the myelin basic protein mRNA that is necessary and sufficient for cytoplasmic transport of this message in oligodendrocytes, The predominant A2RE-binding protein in rat brain has previously been identified as hnRNP A2, Here we report that an 11-nucleotide subsegment of the A2RE (A2RE11) was as effective as the full-length A2RE in binding hnRNP A2 and mediating transport of heterologous RNA in oligodendrocytes, Point mutations of the A2RE11 that eliminated binding to hnRNP A2 also markedly reduced the ability of these oligoribonucleotides to support RNA transport, Oligodendrocytes treated with antisense oligonucleotides directed against the translation start site of hnRNP A2 had reduced levels of this protein and disrupted transport of microinjected myelin basic protein RNA. Several A2RE-like sequences from localized neuronal RNAs also bound hnRNP A2 and promoted RNA transport in oligo-dendrocytes, These data demonstrate the specificity of A2RE recognition by hnRNP A2, provide direct evidence for the involvement of hnRNP A2 in cytoplasmic RNA transport, and suggest that this protein may interact with a wide variety of localized messages that possess A2RE-like sequences

Evidence for osteocyte-mediated bone-matrix degradation associated with periprosthetic joint infection (PJI)

Osteomyelitis associated with periprosthetic joint infection (PJI) signals a chronic infection and the need for revision surgery. An osteomyelitic bone exhibits distinct morphological features, including evidence for osteolysis and an accelerated bone remodelling into poorly organised, poor-quality bone. In addition to immune cells, various bone cell-types have been implicated in the pathology. The present study sought to determine the types of bone-cell activities in human PJI bones. Acetabular biopsies from peri-implant bone from patients undergoing revision total hip replacement (THR) for chronic PJI (with several identified pathogens) as well as control bone from the same patients and from patients undergoing primary THR were analysed. Histological analysis confirmed that PJI bone presented increased osteoclastic activity compared to control bone. Analysis of osteocyte parameters showed no differences in osteocyte lacunar area between the acetabular bone taken from PJI patients or primary THR controls. Analysis of bone matrix composition using Masson's trichrome staining and second-harmonic generation microscopy revealed widespread lack of mature collagen, commonly surrounding osteocytes, in PJI bone. Increased expression of known collagenases, such as matrix metallopeptidase (MMP) 13, MMP1 and cathepsin K (CTSK), was measured in infected bone compared to non-infected bone. Human bone and cultured osteocyte-like cells experimentally exposed to Staphylococcus aureus exhibited strongly upregulated expression of MMP1, MMP3 and MMP13 compared to non-exposed controls. In conclusion, the study identified previously unrecognised bone-matrix changes in PJI caused by multiple organisms deriving from osteocytes. Histological examination of bone collagen composition may provide a useful adjunct diagnostic measure of PJI.R.T. Ormsby, A.R. Zelmer, D. Yang, N.J. Gunn, Y. Starczak, S.P. Kidd ... et al

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Oak Ridge National Laboratory Report CF-59-6-8

The use of a scalloped cross-sectional coolant channel has been suggested as possible solution of the fuel-element bowing problem inherent in the septafoil type of geometry. Using simplified assumptions, a method has been developed for calculating the rod spacing and scallop size necessary to produce equal average fuel-element surface temperatures in the central and peripheral regions of the coolant flow channel at the mid-section of each fuel-rod cluster under a given set of reactor flow conditions. Since the extent of row-bowing is related to the surface temperature distribution, this requirement should minimize fuel-element deflection

Environmental aspects of cooling tower operation: survey of the emission, transport, and deposition of drift from the K-31 and K-33 cooling towers at ORGDP

The results from a program ulo evaluaule the environmental aspeculs of cooling ulower operation at the Oak Ridge Gaseous Diffusion Plan (ORGDP) are presented. The quantities of chemicals being introduced into the atmosphere as well as the deposition of these chemicals on the environs surrounding the cooling towers were measured. Based on the tests performed, the cooling towers, under present operating conditions, are noul causing any adverse effect on the native vegetation surrounding ORGDP. (auth