694 research outputs found

    The economic implications of HLA matching in cadaveric renal transplantation.

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    Abstract Background: The potential economic effects of the allocation of cadaveric kidneys on the basis of tissue-matching criteria are controversial. We analyzed the economic costs associated with the transplantation of cadaveric kidneys with various numbers of HLA mismatches and examined the potential economic benefits of a local, as compared with a national, system designed to minimize HLA mismatches between donor and recipient in first cadaveric renal transplantations. Methods: All data were supplied by the U.S. Renal Data System. Data on all payments made by Medicare from 1991 through 1997 for the care of recipients of a first cadaveric renal transplant were analyzed according to the number of HLA-A, B, and DR mismatches between donor and recipient and the duration of cold ischemia before transplantation. Results: Average Medicare payments for renal-transplant recipients in the three years after transplantation increased from 60,436perpatientforfullyHLAmatchedkidneys(thosewithnoHLAA,B,orDRmismatches)to60,436 per patient for fully HLA-matched kidneys (those with no HLA-A, B, or DR mismatches) to 80,807 for kidneys with six HLA mismatches between donor and recipient, a difference of 34 percent (P\u3c0.001). By three years after transplantation, the average Medicare payments were 64,119fortransplantationsofkidneyswithlessthan12hoursofcoldischemiatimeand64,119 for transplantations of kidneys with less than 12 hours of cold-ischemia time and 74,997 for those with more than 36 hours (P\u3c0.001). In simulations, the assignment of cadaveric kidneys to recipients by a method that minimized HLA mismatching within a local geographic area (i.e., within one of the approximately 50 organ-procurement organizations, which cover widely varying geographic areas) produced the largest cost savings ($4,290 per patient over a period of three years) and the largest improvements in the graft-survival rate (2.3 percent) when the potential costs of longer cold-ischemia time were considered. Conclusions: Transplantation of better-matched cadaveric kidneys could have substantial economic advantages. In our simulations, HLA-based allocation of kidneys at the local level produced the largest estimated cost savings, when the duration of cold ischemia was taken into account. No additional savings were estimated to result from a national allocation program, because the additional costs of longer cold-ischemia time were greater than the advantages of optimizing HLA matching

    Space Environments and Spacecraft Effects Organization Concept

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    The National Aeronautics and Space Administration (NASA) is embarking on a course to expand human presence beyond Low Earth Orbit (LEO) while also expanding its mission to explore the solar system. Destinations such as Near Earth Asteroids (NEA), Mars and its moons, and the outer planets are but a few of the mission targets. Each new destination presents an opportunity to increase our knowledge of the solar system and the unique environments for each mission target. NASA has multiple technical and science discipline areas specializing in specific space environments disciplines that will help serve to enable these missions. To complement these existing discipline areas, a concept is presented focusing on the development of a space environments and spacecraft effects (SENSE) organization. This SENSE organization includes disciplines such as space climate, space weather, natural and induced space environments, effects on spacecraft materials and systems and the transition of research information into application. This space environment and spacecraft effects organization will be composed of Technical Working Groups (TWG). These technical working groups will survey customers and users, generate products, and provide knowledge supporting four functional areas: design environments, engineering effects, operational support, and programmatic support. The four functional areas align with phases in the program mission lifecycle and are briefly described below. Design environments are used primarily in the mission concept and design phases of a program. Engineering effects focuses on the material, component, sub-system and system-level selection and the testing to verify design and operational performance. Operational support provides products based on real time or near real time space weather to mission operators to aid in real time and near-term decision-making. The programmatic support function maintains an interface with the numerous programs within NASA, other federal government agencies, and the commercial sector to ensure that communications are well established and the needs of the programs are being met. The programmatic support function also includes working in coordination with the program in anomaly resolution and generation of lessons learned documentation. The goal of this space environment and spacecraft effects organization is to develop decision-making tools and engineering products to support all mission phases from mission concept through operations by focusing on transitioning research to application. Products generated by this space environments and effects application are suitable for use in anomaly investigations. This paper will describe the scope of the TWGs and their relationship to the functional areas, and discuss an organizational structure for this space environments and spacecraft effects organization

    Key Lessons Learned from Moffitt's Molecular Tumor Board: The Clinical Genomics Action Committee Experience

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    The increasing practicality of genomic sequencing technology has led to its incorporation into routine clinical practice. Successful identification and targeting of driver genomic alterations that provide proliferative and survival advantages to tumor cells have led to approval and ongoing development of several targeted cancer therapies. Within many major cancer centers, molecular tumor boards are constituted to shepherd precision medicine into clinical practice

    Initial genetic dissection of serum neuroactive steroids following chronic intermittent ethanol across BXD mouse strains

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    Neuroactive steroids modulate alcohol’s impact on brain function and behavior. Ethanol exposure alters neuroactive steroid levels in rats, humans, and some mouse strains. We conducted an exploratory analysis of the neuroactive steroids (3α,5α)-3-hydroxypregnan-20-one (3α,5α-THP), (3α,5α)-3,21-dihydroxypregnan-20-one (3α,5α-THDOC), and pregnenolone across 126–158 individuals and 19 fully inbred strains belonging to the BXD family, which were subjected to air exposure, or chronic intermittent ethanol (CIE) exposure. Neuroactive steroids were measured by gas chromatography-mass spectrometry in serum following five cycles of CIE or air exposure (CTL). Pregnenolone levels in CTLs range from 272 to 578 pg/mL (strain variation of 2.1-fold with p = 0.049 for strain main effect), with heritability of 0.20 ± 0.006 (SEM), whereas in CIE cases values range from 304 to 919 pg/mL (3.0-fold variation, p = 0.007), with heritability of 0.23 ± 0.005. 3α,5α-THP levels in CTLs range from 375 to 1055 pg/mL (2.8-fold variation, p = 0.0007), with heritability of 0.28 ± 0.01; in CIE cases they range from 460 to 1022 pg/mL (2.2-fold variation, p = 0.004), with heritability of 0.23 ± 0.005. 3α,5α-THDOC levels in CTLs range from 94 to 448 pg/mL (4.8-fold variation, p = 0.002), with heritability of 0.30 ± 0.01, whereas levels in CIE cases do not differ significantly. However, global averages across all BXD strains do not differ between CTL and CIE for any of the steroids. 3α,5α-THDOC levels were lower in females than males in both groups (CTL −53%, CIE −55%, p < 0.001). Suggestive quantitative trait loci are identified for pregnenolone and 3α,5α-THP levels. Genetic variation in 3α,5α-THP was not correlated with two-bottle choice ethanol consumption in CTL or CIE-exposed animals. However, individual variation in 3α,5α-THP correlated negatively with ethanol consumption in both groups. Moreover, strain variation in neuroactive steroid levels correlated with numerous behavioral phenotypes of anxiety sensitivity accessed in GeneNetwork, consistent with evidence that neuroactive steroids modulate anxiety-like behavior

    Synthesis, photophysics and molecular structures of luminescent 2,5-bis(phenylethynyl)thiophenes (BPETs)

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    International audienceThe Sonogashira cross-coupling of two equivalents of para-substituted ethynylbenzenes with 2,5-diiodothiophene provides a simple synthetic route for the preparation of 2,5-bis(para-R-phenylethynyl)thiophenes (R = H, Me, OMe, CF3, NMe2, NO2, CN and CO2Me) (1a-h). Likewise, 2,5-bis(pentafluorophenylethynyl)thiophene (2) was prepared by the coupling of 2,5-diiodothiophene with pentafluorophenylacetylene. All compounds were characterised by NMR, IR, Raman and mass spectroscopy, elemental analysis, and their absorption and emission spectra, quantum yields and lifetimes were also measured. The spectroscopic studies of 1a-h and 2 show that both electron donating and electron withdrawing para-subsituents on the phenyl rings shift the absorption and emission maxima to lower energies, but that acceptors are more efficient in this regard. The short singlet lifetimes and modest fluorescence quantum yields (ca. 0.2-0.3) observed are characteristic of rapid intersystem crossing. The single-crystal structures of 2,5-bis(phenylethynyl)thiophene, 2,5-bis(para-carbomethoxyphenylethynyl)thiophene, 2,5-bis(para-methylphenylethynyl)thiophene and 2,5-bis(pentafluorophenylethynyl)thiophene were determined by X-ray diffraction at 120 K. DFT calculations show that the all-planar form of the compounds is the lowest in energy, although rotation of the phenyl groups about the C[triple bond, length as m-dash]C bond is facile and TD-DFT calculations suggest that, similar to 1,4-bis(phenylethynyl)benzene analogues, the absorption spectra in solution arise from a variety of rotational conformations. Frequency calculations confirm the assignments of the compounds' IR and Raman spectra

    The role of neuroactive steroids in ethanol/stress interactions: proceedings of symposium VII at the Volterra conference on alcohol and stress, May 2008

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    This report summarizes the proceedings of the symposium VII on the role of neuroactive steroids in stress/alcohol interactions. The production of GABAergic neuroactive steroids, including (3α,5α)-3-hydroxypregnan-20-one (3α,5α-THP) and (3α,5α)-3,21-dihydroxypregnan-20-one (3α,5α-THDOC) is a consequence of both acute stress and acute ethanol exposure. Acute, but not chronic ethanol administration elevates brain levels of these steroids and enhances GABAA receptor activity. Neuroactive steroids modulate acute anticonvulsant effects, sedation, spatial memory impairment, anxiolytic-like, antidepressant-like and reinforcing properties of ethanol in rodents. Furthermore, these steroids participate in the homeostatic regulation of the hypothalamic-pituitary-adrenal (HPA) axis. Therefore, it is not surprising that neuroactive steroids are involved in ethanol/stress interactions. Nevertheless, the interactions are complex and not well understood. This symposium addressed the role of neuroactive steroids in both stress and alcohol responses and their interactions. Professor Giovanni Biggio of the University of Cagliari, Italy presented the effects of juvenile isolation stress on neuroactive steroids, GABAA receptor expression and ethanol sensitivity. Professor Howard Becker of the Medical University of South Carolina, USA presented evidence for neuroactive steroid involvement in ethanol dependence and drinking behavior. Professor Patrizia Porcu of the University of North Carolina, USA described a potential neuroactive steroid biomarker that may predict heavy drinking in monkeys and mice. These presentations provide a framework for new theories on the nature of ethanol/stress interactions that may be amenable to therapeutic interventions

    Discovery and Rossiter-McLaughlin Effect of Exoplanet Kepler-8b

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    We report the discovery and the Rossiter-McLaughlin effect of Kepler-8b, a transiting planet identified by the NASA Kepler Mission. Kepler photometry and Keck-HIRES radial velocities yield the radius and mass of the planet around this F8IV subgiant host star. The planet has a radius RP = 1.419 RJ and a mass, MP = 0.60 MJ, yielding a density of 0.26 g cm^-3, among the lowest density planets known. The orbital period is P = 3.523 days and orbital semima jor axis is 0.0483+0.0006/-0.0012 AU. The star has a large rotational v sin i of 10.5 +/- 0.7 km s^-1 and is relatively faint (V = 13.89 mag), both properties deleterious to precise Doppler measurements. The velocities are indeed noisy, with scatter of 30 m s^-1, but exhibit a period and phase consistent with the planet implied by the photometry. We securely detect the Rossiter-McLaughlin effect, confirming the planet's existence and establishing its orbit as prograde. We measure an inclination between the projected planetary orbital axis and the projected stellar rotation axis of lambda = -26.9 +/- 4.6 deg, indicating a moderate inclination of the planetary orbit. Rossiter-McLaughlin measurements of a large sample of transiting planets from Kepler will provide a statistically robust measure of the true distribution of spin-orbit orientations for hot jupiters in general.Comment: 26 pages, 8 figures, 2 tables; In preparation for submission to the Astrophysical Journa

    Compressional-mode resonances in the molybdenum isotopes: Emergence of softness in open-shell nuclei near A=90

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    "Why are the tin isotopes soft?" has remained, for the past decade, an open problem in nuclear structure physics: models which reproduce the isoscalar giant monopole resonance (ISGMR) in the "doubly-closed shell" nuclei, 90^{90}Zr and 208^{208}Pb, overestimate the ISGMR energies of the open-shell tin and cadmium nuclei, by as much as 1 MeV. In an effort to shed some light onto this problem, we present results of detailed studies of the ISGMR in the molybdenum nuclei, with the goal of elucidating where--and how--the softness manifests itself between 90^{90}Zr and the cadmium and tin isotopes. The experiment was conducted using the 94,96,98,100^{94,96,98,100}Mo(α,α\alpha,\alpha^\prime) reaction at Eα=386E_\alpha = 386 MeV. A comparison of the results with relativistic, self-consistent Random-Phase Approximation calculations indicates that the ISGMR response begins to show softness in the molybdenum isotopes beginning with A=92A=92.Comment: Accepted for publication to Physics Letters

    Paracheck-Pf® accuracy and recently treated Plasmodium falciparum infections: is there a risk of over-diagnosis?

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    BACKGROUND: An assessment of the accuracy of Paracheck Pf, a malaria rapid diagnostic test (RDT) detecting histidine rich protein 2 was undertaken amongst children aged 6-59 months in eastern Democratic Republic of Congo. METHODS: This RDT assessment occurred in conjunction with an ACT efficacy trial. Febrile children were simultaneously screened with both RDT and high quality microscopy and those meeting inclusion criteria were followed for 35 days. RESULTS: 358 febrile children were screened with 180 children recruited for five weeks follow-up. On screening, the RDT accurately diagnosed all 235 true malaria cases, indicating 100% RDT sensitivity. Of the 123 negative slides, the RDT gave 59 false-positive results, indicating 52.0% (64/123) RDT specificity. During follow-up after treatment with an artemisinin-based combination therapy, 98.2% (110/112), 94.6% (106/112), 92.0% (103/112) and 73.5% (50/68) of effectively treated children were still false-positive by RDT at days 14, 21, 28 and 35, respectively. CONCLUSION: Results show that though the use of Paracheck-Pf is as sensitive as microscopy in detecting true malaria cases, a low specificity did present a high frequency of false-positive RDT results. What's more, a duration of RDT false-positivity was found that significantly surpassed the 'fortnight' after effective treatment reported by its manufacturer. Though further research is needed in assessing RDT accuracy, study results showing the presence of frequent false positivity should be taken into consideration to avoid clinicians inappropriately focusing on malaria, not identifying the true cause of illness, and providing unnecessary treatment

    The Ruegeria pomeroyi acuI Gene Has a Role in DMSP Catabolism and Resembles yhdH of E. coli and Other Bacteria in Conferring Resistance to Acrylate

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    The Escherichia coli YhdH polypeptide is in the MDR012 sub-group of medium chain reductase/dehydrogenases, but its biological function was unknown and no phenotypes of YhdH− mutants had been described. We found that an E. coli strain with an insertional mutation in yhdH was hyper-sensitive to inhibitory effects of acrylate, and, to a lesser extent, to those of 3-hydroxypropionate. Close homologues of YhdH occur in many Bacterial taxa and at least two animals. The acrylate sensitivity of YhdH− mutants was corrected by the corresponding, cloned homologues from several bacteria. One such homologue is acuI, which has a role in acrylate degradation in marine bacteria that catabolise dimethylsulfoniopropionate (DMSP) an abundant anti-stress compound made by marine phytoplankton. The acuI genes of such bacteria are often linked to ddd genes that encode enzymes that cleave DMSP into acrylate plus dimethyl sulfide (DMS), even though these are in different polypeptide families, in unrelated bacteria. Furthermore, most strains of Roseobacters, a clade of abundant marine bacteria, cleave DMSP into acrylate plus DMS, and can also demethylate it, using DMSP demethylase. In most Roseobacters, the corresponding gene, dmdA, lies immediately upstream of acuI and in the model Roseobacter strain Ruegeria pomeroyi DSS-3, dmdA-acuI were co-regulated in response to the co-inducer, acrylate. These observations, together with findings by others that AcuI has acryloyl-CoA reductase activity, lead us to suggest that YdhH/AcuI enzymes protect cells against damaging effects of intracellular acryloyl-CoA, formed endogenously, and/or via catabolising exogenous acrylate. To provide “added protection” for bacteria that form acrylate from DMSP, acuI was recruited into clusters of genes involved in this conversion and, in the case of acuI and dmdA in the Roseobacters, their co-expression may underpin an interaction between the two routes of DMSP catabolism, whereby the acrylate product of DMSP lyases is a co-inducer for the demethylation pathway
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