545 research outputs found

    Ethical Issues in Organ Procurement and Transplantation

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    The Ciba Foundation held the first international, interdisciplinary conference on ethical and legal issues in transplantation in March 1966. Many of the ethical issues discussed at that conference remain with us today. Organ procurement and transplantation have forced the medical community and society at large to ask such fundamental questions as when are we dead, how can death be declared so that any life‐support measures can be discontinued? Is it ethical to remove an organ or part of an organ from a living person? Since there is such a shortage of organ and people on transplant waiting lists die for lack of an organ, what types of incentives, if any, can be used to increase the organ supply? Transplant centers face additional ethical issues. How can a limited supply of organs be fairly allocated to a large number of patients on the waiting list? Are the methods of putting patients on the waiting list appropriate? Transplant centers are regulated by a variety of governmental organizations. These organizations may have performance criteria. Do these performance criteria lead transplant centers to modify which organs they will accept or which patients they will list? As long as a shortage of organs remains, these ethical issues are likely to persist

    Exponential decontamination models for count data

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    Several models are developed for the estimation of the rate of exponential die-off from decontamination data. Calculations with illustrative data are reported which indicate that the estimation of this rate and its variance are sensitive to changes in modelling assumptions. Since extrapolation using this estimated rate is used in the specification of planetary quarantine standards, special care should be taken in the selection of an appropriate model and corresponding estimation procedure for the analysis of each set of decontamination data to be used for this purpose.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43352/1/11084_2004_Article_BF00924214.pd

    Predicting the long-term impact of antiretroviral therapy scale-up on population incidence of tuberculosis.

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    OBJECTIVE: To investigate the impact of antiretroviral therapy (ART) on long-term population-level tuberculosis disease (TB) incidence in sub-Saharan Africa. METHODS: We used a mathematical model to consider the effect of different assumptions about life expectancy and TB risk during long-term ART under alternative scenarios for trends in population HIV incidence and ART coverage. RESULTS: All the scenarios we explored predicted that the widespread introduction of ART would initially reduce population-level TB incidence. However, many modelled scenarios projected a rebound in population-level TB incidence after around 20 years. This rebound was predicted to exceed the TB incidence present before ART scale-up if decreases in HIV incidence during the same period were not sufficiently rapid or if the protective effect of ART on TB was not sustained. Nevertheless, most scenarios predicted a reduction in the cumulative TB incidence when accompanied by a relative decline in HIV incidence of more than 10% each year. CONCLUSIONS: Despite short-term benefits of ART scale-up on population TB incidence in sub-Saharan Africa, longer-term projections raise the possibility of a rebound in TB incidence. This highlights the importance of sustaining good adherence and immunologic response to ART and, crucially, the need for effective HIV preventive interventions, including early widespread implementation of ART

    Adaptable-radius, time-orbiting magnetic ring trap for Bose-Einstein condensates

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    We theoretically investigate an adjustable-radius magnetic storage ring for laser-cooled and Bose-condensed atoms. Additionally, we discuss a novel time-dependent variant of this and other ring traps. Time-orbiting ring traps provide a high optical access method for spin-flip loss prevention near a storage ring's circular magnetic field zero. Our scalable storage ring will allow one to probe the fundamental limits of condensate Sagnac interferometry.Comment: 5 pages, 3 figures. accepted in J Phys

    Banff Digital Pathology Working Group: Going digital in transplant pathology.

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    The Banff Digital Pathology Working Group (DPWG) was formed in the time leading up to and during the joint American Society for Histocompatibility and Immunogenetics/Banff Meeting, September 23-27, 2019, held in Pittsburgh, Pennsylvania. At the meeting, the 14th Banff Conference, presentations directly and peripherally related to the topic of "digital pathology" were presented; and discussions before, during, and after the meeting have resulted in a list of issues to address for the DPWG. Included are practice standardization, integrative approaches for study classification, scoring of histologic parameters (eg, interstitial fibrosis and tubular atrophy and inflammation), algorithm classification, and precision diagnosis (eg, molecular pathways and therapeutics). Since the meeting, a survey with international participation of mostly pathologists (81%) was conducted, showing that whole slide imaging is available at the majority of centers (71%) but that artificial intelligence (AI)/machine learning was only used in ≈12% of centers, with a wide variety of programs/algorithms employed. Digitalization is not just an end in itself. It also is a necessary precondition for AI and other approaches. Discussions at the meeting and the survey highlight the unmet need for a Banff DPWG and point the way toward future contributions that can be made

    Outcome of primary resurfacing hip replacement: evaluation of risk factors for early revision: 12,093 replacements from the Australian Joint Registry

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    BACKGROUND AND PURPOSE: The outcome of modern resurfacing remains to be determined. The Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) started collection of data on hip resurfacing at a time when modern resurfacing was started in Australia. The rate of resurfacing has been higher in Australia than in many other countries. As a result, the AOANJRR has one of the largest series of resurfacing procedures. This study was undertaken to determine the results of this series and the risk factors associated with revision. PATIENTS AND METHODS: Data from the AOANJRR were used to analyze the survivorship of 12,093 primary resurfacing hip replacements reported to the Joint Replacement Registry between September 1999 and December 2008. This was compared to the results of primary conventional total hip replacement reported during the same period. The Kaplan-Meier method and proportional hazards models were used to determine risk factors such as age, sex, femoral component size, primary diagnosis, and implant design. RESULTS: Female patients had a higher revision rate than males; however, after adjusting for head size, the revision rates were similar. Prostheses with head sizes of less than 50 mm had a higher revision rate than those with head sizes of 50 mm or more. At 8 years, the cumulative per cent revision of hip resurfacing was 5.3 (4.6-6.2), as compared to 4.0 (3.8-4.2) for total hip replacement. However, in osteoarthritis patients aged less than 55 years with head sizes of 50 mm or more, the 7-year cumulative per cent revision for hip resurfacing was 3.0 (2.2-4.2). Also, hips with dysplasia and some implant designs had an increased risk of revision. INTERPRETATION: Risk factors for revision of resurfacing were older patients, smaller femoral head size, patients with developmental dysplasia, and certain implant designs. These results highlight the importance of patient and prosthesis selection in optimizing the outcome of hip resurfacing

    Radiation Impairs Perineural Invasion by Modulating the Nerve Microenvironment

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    Perineural invasion (PNI) by cancer cells is an ominous clinical event that is associated with increased local recurrence and poor prognosis. Although radiation therapy (RT) may be delivered along the course of an invaded nerve, the mechanisms through which radiation may potentially control PNI remain undefined. murine sciatic nerve model was used to study how RT to nerve or cancer affects nerve invasion by cancer.Cancer cell invasion of the DRG was partially dependent on DRG secretion of glial-derived neurotrophic factor (GDNF). A single 4 Gy dose of radiation to the DRG alone, cultured with non-radiated cancer cells, significantly inhibited PNI and was associated with decreased GDNF secretion but intact DRG viability. Radiation of cancer cells alone, co-cultured with non-radiated nerves, inhibited PNI through predominantly compromised cancer cell viability. In a murine model of PNI, a single 8 Gy dose of radiation to the sciatic nerve prior to implantation of non-radiated cancer cells resulted in decreased GDNF expression, decreased PNI by imaging and histology, and preservation of sciatic nerve motor function.Radiation may impair PNI through not only direct effects on cancer cell viability, but also an independent interruption of paracrine mechanisms underlying PNI. RT modulation of the nerve microenvironment may decrease PNI, and hold significant therapeutic implications for RT dosing and field design for patients with cancers exhibiting PNI
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