414 research outputs found

    Stereotactic body radiation therapy for hepatocellular carcinoma: Practice patterns, dose selection and factors impacting survival

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    Background Stereotactic body radiation therapy (SBRT) is an emerging option for unresectable hepatocellular carcinoma (HCC) without consensus regarding optimal dose schemas. This analysis identifies practice patterns and factors that influence dose selection and overall survival, with particular emphasis on dose and tumor size. Materials/Methods Query of the National Cancer Database (NCDB) identified patients with unresectable, nonmetastatic HCC who received SBRT from 2004 to 2013. Biological Effective Dose (BED) was calculated for each patient in order to uniformly analyze different fractionation regimens. Results A total of 456 patients met the inclusion criteria. The median BED was 100 Gy (22.5-208.0), which corresponded to the most common dose fractionation (50 Gy in five fractions). Various factors influenced dose selection including tumor size (P 2 to 4 months, HR 2.192, P < 0.001) were associated with worse survival. Conclusion SBRT use is increasing for HCC, and multiple regimens are clinically employed. Although high BED was associated with improved outcomes, multiple factors contributed to the dose selection with favorable patients receiving higher doses. Continued efforts to enhance radiation planning and delivery may help improve utilization, safety, and efficacy.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

    Primary care access and foregone care: A survey of transgender adolescents and young adults

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    Objective. To examine the issues of primary care access and foregone health care among transgender adolescents and young adults. Methods. This cross-sectional analysis of data from the Canadian Trans Youth Health Survey was conducted online during 2013–2014. Participants included 923 youth aged 14–25 (323 adolescents aged 14–18 and 600 young adults aged 19–25). Main outcome measures were self-reported general and mental health status, comfort discussing transgender identity and health care needs with general practitioners, and types of and reasons for self-identified foregone health care. Results. Most youth reported poor/fair general and mental health status. Comfort with a family doctor was positively correlated with both general health (r(528) = 21, P < 0.001) and mental health (r(450) = 26, P < 0.001) status, as was having a doctor who was aware of one’s transgender status. 47.2% (n = 219) of young adults reported foregoing needed health care. Among adolescents, levels of comfort with family doctor were negatively correlated with foregone mental health care in the previous 12 months (F₃,₁₆₆ = 3.829, P = 0.011), but not correlated with foregone physical health care (F₃,₁₆₅ = 0.506, P = 0.679). Reasons for missing needed care spanned the dimensions of health care access, ranging from cost barriers to previous negative experiences with health care providers, and concerns that a doctor would be uneducated about transgender people. Conclusion. General practitioners can play a key role in improving the health of transgender youth by demonstrating understanding of the health care needs of transgender youth and competence in gender-affirming care, and by ensuring that their practices are accessible to all transgender youth in need of care

    Midkine mediates intercellular crosstalk between drug-resistant and drug sensitive neuroblastoma cells in vitro and in vivo

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    Resistance to cytotoxic agents has long been known to be a major limitation in the treatment of human cancers. Although many mechanisms of drug resistance have been identified, chemotherapies targeting known mechanisms have failed to lead to effective reversal of drug resistance, suggesting that alternative mechanisms remain undiscovered. Previous work identified midkine (MK) as a novel putative survival molecule responsible for cytoprotective signaling between drug-resistant and drug-sensitive neuroblastoma, osteosarcoma and breast carcinoma cells in vitro. In the present study, we provide further in vitro and in vivo studies supporting the role of MK in neuroblastoma cytoprotection. MK overexpressing wild type neuroblastoma cells exhibit a cytoprotective effect on wild type cells when grown in a co-culture system, similar to that seen with doxorubicin resistant cells. siRNA knockdown of MK expression in doxorubicin resistant neuroblastoma and osteosarcoma cells ameliorates this protective effect. Overexpression of MK in wild type neuroblastoma cells leads to acquired drug resistance to doxorubicin and to the related drug etoposide. Mouse studies injecting various ratios of doxorubicin resistant or MK transfected cells with GFP transfected wild type cells confirm this cytoprotective effect in vivo. These findings provide additional evidence for the existence of intercellular cytoprotective signals mediated by MK which contribute to chemotherapy resistance in neuroblastoma

    The adverse effects of reduced cerebral perfusion on cognition and brain structure in older adults with cardiovascular disease

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    BACKGROUND: It is well established that aging and vascular processes interact to disrupt cerebral hemodynamics in older adults. However, the independent effects of cerebral perfusion on neurocognitive function among older adults remain poorly understood. We examined the associations among cerebral perfusion, cognitive function, and brain structure in older adults with varying degrees of vascular disease using perfusion magnetic resonance imaging (MRI) arterial spin labeling (ASL). MATERIALS AND METHODS: 52 older adults underwent neuroimaging and were administered the Mini Mental State Examination (MMSE), the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and measures of attention/executive function. ASL and T1-weighted MRI were used to quantify total brain perfusion, total brain volume (TBV), and cortical thickness. RESULTS: Regression analyses showed reduced total brain perfusion was associated with poorer performance on the MMSE, RBANS total index, immediate and delayed memory composites, and Trail Making Test B. Reduced frontal lobe perfusion was associated with worse executive and memory function. A similar pattern emerged between temporal lobe perfusion and immediate memory. Regression analyses revealed that decreased total brain perfusion was associated with smaller TBV and mean cortical thickness. Regional effects of reduced total cerebral perfusion were found on temporal and parietal lobe volumes and frontal and temporal cortical thickness. DISCUSSION: Reduced cerebral perfusion is independently associated with poorer cognition, smaller TBV, and reduced cortical thickness in older adults. CONCLUSION: Prospective studies are needed to clarify patterns of cognitive decline and brain atrophy associated with cerebral hypoperfusion

    Entanglement-assisted quantum low-density parity-check codes

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    This paper develops a general method for constructing entanglement-assisted quantum low-density parity-check (LDPC) codes, which is based on combinatorial design theory. Explicit constructions are given for entanglement-assisted quantum error-correcting codes (EAQECCs) with many desirable properties. These properties include the requirement of only one initial entanglement bit, high error correction performance, high rates, and low decoding complexity. The proposed method produces infinitely many new codes with a wide variety of parameters and entanglement requirements. Our framework encompasses various codes including the previously known entanglement-assisted quantum LDPC codes having the best error correction performance and many new codes with better block error rates in simulations over the depolarizing channel. We also determine important parameters of several well-known classes of quantum and classical LDPC codes for previously unsettled cases.Comment: 20 pages, 5 figures. Final version appearing in Physical Review

    “What if There's Something Wrong with Her?”‐How Biomedical Technologies Contribute to Epistemic Injustice in Healthcare

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    While there is a steadily growing literature on epistemic injustice in healthcare, there are few discussions of the role that biomedical technologies play in harming patients in their capacity as knowers. Through an analysis of newborn and pediatric genetic and genomic sequencing technologies (GSTs), I argue that biomedical technologies can lead to epistemic injustice through two primary pathways: epistemic capture and value partitioning. I close by discussing the larger ethical and political context of critical analyses of GSTs and their broader implications for just and equitable healthcare delivery

    Rewards for Ratification: Payoffs for Participating in the International Human Rights Regime?

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    Among the explanations for state ratification of human rights treaties, few are more common and widely accepted than the conjecture that states are rewarded for ratification by other states. These rewards are expected to come in the form of tangible benefits - foreign aid, trade, and investment - and intangible benefits such as praise, acceptance, and legitimacy. Surprisingly, these explanations for ratification have never been tested empirically. We summarize and clarify the theoretical underpinnings of "reward-for-ratification" theories and test these propositions empirically by looking for increased international aid, economic agreements and public praise and recognition following ratification of four prominent human rights treaties. We find almost no evidence that states can expect increased tangible or intangible rewards after ratification. Given the lack of empirical support, alternative explanations seem more appealing for understanding human rights treaty ratification.Governmen
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