18,185 research outputs found

    Clinical intestinal transplantation: New perspectives and immunologic considerations

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    Background: Although tacrolimus-based immunosuppression has made intestinal transplantation feasible, the risk of the requisite chronic high- dose treatment has inhibited the widespread use of these procedures. We have examined our 1990-1997 experience to determine whether immunomodulatory strategies to improve outlook could be added to drug treatment. Study Design: Ninety-eight consecutive patients (59 children, 39 adults) with a panoply of indications received 104 allografts under tacrolimus-based immunosuppression: intestine only (n = 37); liver and intestine (n = 50); or multivisceral (n = 17). Of the last 42 patients, 20 received unmodified adjunct donor bone marrow cells; the other 22 were contemporaneous control patients. Results: With a mean followup of 32 ± 26 months (range, 1-86 months), 12 recipients (3 intestine only, 9 composite grafts) are alive with good nutrition beyond the 5-year milestone. Forty-seven (48%) of the total group survive bearing grafts that provide full (91%) or partial (9%) nutrition. Actuarial patient survival at 1 and 5 years (72% and 48%, respectively) was similar with isolated intestinal and composite graft recipients, but the loss rate of grafts from rejection was highest with intestine alone. The best results were in patients between 2 and 18 years of age (68% at 5 years). Adjunct bone marrow did not significantly affect the incidence of graft rejection, B-cell lymphoma, or the rate or severity of graft-versus-host disease. Conclusions: These results demonstrate that longterm rehabilitation similar to that with the other kinds of organ allografts is achievable with all three kinds of intestinal transplant procedures, that the morbidity and mortality is still too high for their widespread application, and that the liver is significantly but marginally protective of concomitantly engrafted intestine. Although none of the endpoints were markedly altered by donor leukocyte augmentation (and chimerism) with bone marrow, establishment of the safety of this adjunct procedure opens the way to further immune modulation strategies that can be added to the augmentation protocol

    Pancreatic cancer clusters and arsenic-contaminated drinking water wells in Florida

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    This is the final version of the article. Available from BioMed Central via the DOI in this record.BACKGROUND: We sought to identify high-risk areas of pancreatic cancer incidence, and determine if clusters of persons diagnosed with pancreatic cancer were more likely to be located near arsenic-contaminated drinking water wells. METHODS: A total of 5,707 arsenic samples were collected from December 2000 to May 2008 by the Florida Department of Health, representing more than 5,000 individual privately owned wells. During that period, 0.010 ppm (10 ppb) or greater arsenic levels in private well water were considered as the threshold based on standard of United States Environmental Protection Agency (EPA). Spatial modeling was applied to pancreatic cancer cases diagnosed between 1998-2002 in Florida (n = 11,405). Multivariable logistic regression was used to determine if sociodemographic indicators, smoking history, and proximity to arsenic-contaminated well sites were associated with residence at the time of pancreatic cancer diagnosis occurring within versus outside a cluster. RESULTS: Spatial modeling identified 16 clusters in which 22.6% of all pancreatic cancer cases were located. Cases living within 1 mile of known arsenic-contaminated wells were significantly more likely to be diagnosed within a cluster of pancreatic cancers relative to cases living more than 3 miles from known sites (odds ratio = 2.1 [95% CI = 1.9, 2.4]). CONCLUSIONS: Exposure to arsenic-contaminated drinking water wells may be associated with an increased risk of pancreatic cancer. However, case-control studies are needed in order to confirm the findings of this ecological analysis. These cluster areas may be appropriate to evaluate pancreatic cancer risk factors, and to perform targeted screening and prevention studies.The project was supported by grants from the James and Esther King Biomedical Research Foundation (#06TSP); the Bankhead-Coley Cancer Research Program (#1BG06-341963, #08BN-03), the Florida Department of Health (FDOH); the CDC National Program of Cancer Registries (CDC NPCR); and the European Union ERDF funding (University of Exeter)

    The cytotoxic effects of lipidic formulated gold porphyrin nanoparticles for the treatment of neuroblastoma

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    Objective: Nanotechnology has been identified as a promising platform in the improvement of the design and development of drug delivery systems. In the present study we investigated the potential of lipidic nanoparticles consisting of gold porphyrin for the treatment of neuroblastoma. Materials and methods: To characterize the size of the lipidic gold porphyrin nanoparticles, we used transmission electron microscopy (TEM). The in vitro cytotoxic effect on neuroblastoma activity was examined using XTT cell proliferation assay, then IC50 values were calculated. In vivo safety and toxicity were studied using intraperitoneal injection of gold porphyrin nanoparticles into normal animals. Finally, tumor size measurement and animal survival were studied to investigate the therapeutic effect of lipidic gold porphyrin nanoparticles on neuroblastoma growth. Results: We found that incorporation of gold porphyrin into lipidic nanoparticles resulted in a 16-fold increase in size. Subsequent in vitro and in vivo cytotoxicity studies further showed that the lipidic gold porphyrin nanoparticles could decrease systemic toxicity, as well as inhibiting tumor growth following administration into the neuroblastoma bearing mice. Conclusion: The delivery of lipidic gold porphyrin nanoparticles by incorporation with lipidic formulation is feasible approach to treat neuroblastoma. We await further studies to evaluate tumor killing kinetics. © 2010 Lee et al, publisher and licensee Dove Medical Press Ltd.published_or_final_versio

    Impedance Monitoring During Radiofrequency Catheter Ablation in Humans

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73768/1/j.1540-8159.1992.tb02897.x.pd

    A simple and robust method for connecting small-molecule drugs using gene-expression signatures

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    Interaction of a drug or chemical with a biological system can result in a gene-expression profile or signature characteristic of the event. Using a suitably robust algorithm these signatures can potentially be used to connect molecules with similar pharmacological or toxicological properties. The Connectivity Map was a novel concept and innovative tool first introduced by Lamb et al to connect small molecules, genes, and diseases using genomic signatures [Lamb et al (2006), Science 313, 1929-1935]. However, the Connectivity Map had some limitations, particularly there was no effective safeguard against false connections if the observed connections were considered on an individual-by-individual basis. Further when several connections to the same small-molecule compound were viewed as a set, the implicit null hypothesis tested was not the most relevant one for the discovery of real connections. Here we propose a simple and robust method for constructing the reference gene-expression profiles and a new connection scoring scheme, which importantly allows the valuation of statistical significance of all the connections observed. We tested the new method with the two example gene-signatures (HDAC inhibitors and Estrogens) used by Lamb et al and also a new gene signature of immunosuppressive drugs. Our testing with this new method shows that it achieves a higher level of specificity and sensitivity than the original method. For example, our method successfully identified raloxifene and tamoxifen as having significant anti-estrogen effects, while Lamb et al's Connectivity Map failed to identify these. With these properties our new method has potential use in drug development for the recognition of pharmacological and toxicological properties in new drug candidates.Comment: 8 pages, 2 figures, and 2 tables; supplementary data supplied as a ZIP fil

    Effective Lagrangian approach to vector mesons, their structure and decays)^{*)}

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    An improved update of the structure and decays of ρ0\rho^0, ω\omega and ϕ\phi mesons based on a chiral SU(3) Lagrangian, including anomaly terms is presented. We demonstrate that a consistent and quantitatively successful description of both pion and kaon electromagnetic form factors can be achieved. We also discuss the e+eπ+π0πe^+e^- \to \pi^+ \pi^0 \pi^- cross section, the Dalitz decay ωπ0μ+μ\omega \to \pi^0 \mu^+ \mu^- and aspects of ρ0ω\rho^0 \omega and ωϕ\omega \phi mixing. Relations to previous versions of the Vector Meson Dominance model will be examined.Comment: 35 pages, TeX, 14 ps figures, submitted to Z.Phys.

    Atomic-scale combination of germanium-zinc nanofibers for structural and electrochemical evolution

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    Alloys are recently receiving considerable attention in the community of rechargeable batteries as possible alternatives to carbonaceous negative electrodes; however, challenges remain for the practical utilization of these materials. Herein, we report the synthesis of germanium-zinc alloy nanofibers through electrospinning and a subsequent calcination step. Evidenced by in situ transmission electron microscopy and electrochemical impedance spectroscopy characterizations, this one-dimensional design possesses unique structures. Both germanium and zinc atoms are homogenously distributed allowing for outstanding electronic conductivity and high available capacity for lithium storage. The as-prepared materials present high rate capability (capacity of similar to 50% at 20 C compared to that at 0.2 C-rate) and cycle retention (73% at 3.0 C-rate) with a retaining capacity of 546 mAh g(-1) even after 1000 cycles. When assembled in a full cell, high energy density can be maintained during 400 cycles, which indicates that the current material has the potential to be used in a large-scale energy storage system

    Skyrmion fluctuations at a first-order phase transition boundary

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    Magnetic skyrmions are topologically protected spin textures with promising prospects for applications in data storage. They can form a lattice state due to competing magnetic interactions and are commonly found in a small region of the temperature - magnetic field phase diagram. Recent work has demonstrated that these magnetic quasi-particles fluctuate at the μeV energy scale. Here, we use a coherent x-ray correlation method at an x-ray free-electron laser to investigate these fluctuations in a magnetic phase coexistence region near a first-order transition boundary where fluctuations are not expected to play a major role. Surprisingly, we find that the relaxation of the intermediate scattering function at this transition differs significantly compared to that deep in the skyrmion lattice phase. The observation of a compressed exponential behavior suggests solid-like dynamics, often associated with jamming. We assign this behavior to disorder and the phase coexistence observed in a narrow field-window near the transition, which can cause fluctuations that lead to glassy behavior

    Two-dimensional universal conductance fluctuations and the electron-phonon interaction of topological surface states in Bi2Te2Se nanoribbons

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    The universal conductance fluctuations (UCFs), one of the most important manifestations of mesoscopic electronic interference, have not yet been demonstrated for the two-dimensional surface state of topological insulators (TIs). Even if one delicately suppresses the bulk conductance by improving the quality of TI crystals, the fluctuation of the bulk conductance still keeps competitive and difficult to be separated from the desired UCFs of surface carriers. Here we report on the experimental evidence of the UCFs of the two-dimensional surface state in the bulk insulating Bi2Te2Se nanoribbons. The solely-B\perp-dependent UCF is achieved and its temperature dependence is investigated. The surface transport is further revealed by weak antilocalizations. Such survived UCFs of the topological surface states result from the limited dephasing length of the bulk carriers in ternary crystals. The electron-phonon interaction is addressed as a secondary source of the surface state dephasing based on the temperature-dependent scaling behavior

    Colored Motifs Reveal Computational Building Blocks in the C. elegans Brain

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    Background: Complex networks can often be decomposed into less complex sub-networks whose structures can give hints about the functional organization of the network as a whole. However, these structural motifs can only tell one part of the functional story because in this analysis each node and edge is treated on an equal footing. In real networks, two motifs that are topologically identical but whose nodes perform very different functions will play very different roles in the network. Methodology/Principal Findings: Here, we combine structural information derived from the topology of the neuronal network of the nematode C. elegans with information about the biological function of these nodes, thus coloring nodes by function. We discover that particular colorations of motifs are significantly more abundant in the worm brain than expected by chance, and have particular computational functions that emphasize the feed-forward structure of information processing in the network, while evading feedback loops. Interneurons are strongly over-represented among the common motifs, supporting the notion that these motifs process and transduce the information from the sensor neurons towards the muscles. Some of the most common motifs identified in the search for significant colored motifs play a crucial role in the system of neurons controlling the worm's locomotion. Conclusions/Significance: The analysis of complex networks in terms of colored motifs combines two independent data sets to generate insight about these networks that cannot be obtained with either data set alone. The method is general and should allow a decomposition of any complex networks into its functional (rather than topological) motifs as long as both wiring and functional information is available
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