Cost of lifetime immunosuppression coverage for kidney transplant recipients.

On January 1, 2000, Medicare extended the coverage of immunosuppression medications from 3 years to life for elderly and disabled kidney transplant recipients. This research estimates the impact of extending this lifetime coverage to all kidney transplant recipients on Medicare\u27s cash flows. The study finds that extending coverage to all kidney transplant recipients would have increased Medicare\u27s net cash outflows if the coverage were extended for patients of all income levels. There is evidence that extending coverage to only patients in the lowest income quartile could have resulted in a net cost savings to Medicare

Materials and pathways of the organic carbon cycle through time

The cycle of organic carbon through the atmosphere, oceans, continents and mantle reservoirs is a hallmark of Earth. Over geological time, chemical exchanges between those reservoirs have produced a diversity of reduced carbon materials that differ in their molecular structures and reactivity. This reactive complexity challenges the canonical dichotomy between the surface and deep, short-term and long-term organic carbon cycle. Old and refractory carbon materials are not confined to the lithosphere but are ubiquitous in the surface environment, and the lithosphere hosts various forms of reduced carbon that can be very reactive. The biological and geological pathways that drive the organic carbon cycle have changed through time; from a synthesis of these changes, it emerges that although a biosphere is required to produce organic carbon, mortality is required to ensure its export to the lithosphere, and graphitization is essential for its long-term stabilization in the solid Earth. Among the by-products of the organic carbon cycle are the accumulation of a massive lithospheric reservoir of organic carbon, the accumulation of dioxygen in the atmosphere and the rise of a terrestrial biosphere. Besides driving surface weathering reactions, free dioxygen has allowed the evolution of new metabolic pathways to produce and respire organic carbon. From the evolution of photosynthesis until the expansion of biomineralization in the Phanerozoic, inorganic controls on the organic carbon cycle have diversified, tightening the connection between the biosphere and geosphere

Uncontrolled pain:a call for better study design

Studies assessing animal pain in veterinary research are often performed primarily for the benefit of animals. Frequently, the goal of these studies is to determine whether the analgesic effect of a novel treatment is clinically meaningful, and therefore has the capacity to improve the welfare of treated animals. To determine the treatment effect of a potential analgesic, control groups are necessary to allow comparison. There are negative control groups (where pain is unattenuated) and positive control groups (where pain is attenuated). Arising out of animal welfare concerns, there is growing reluctance to use negative control groups in pain studies. But for studies where pain is experimentally induced, the absence of a negative control group removes the opportunity to demonstrate that the study methods could differentiate a positive control intervention from doing nothing at all. For studies that are controlled by a single comparison group, the capacity to distinguish treatment effects from experimental noise is more difficult; especially considering that pain studies often involve small sample sizes, small and variable treatment effects, systematic error and use pain assessment measures that are unreliable. Due to these limitations, and with a focus on farm animals, we argue that many pain studies would be enhanced by the simultaneous inclusion of positive and negative control groups. This would help provide study-specific definitions of pain and pain attenuation, thereby permitting more reliable estimates of treatment effects. Adoption of our suggested refinements could improve animal welfare outcomes for millions of animals globally.</p

Risk prediction in patients with heart failure: A systematic review and analysis

Objectives This study sought to review the literature for risk prediction models in patients with heart failure and to identify the most consistently reported independent predictors of risk across models. Background Risk assessment provides information about patient prognosis, guides decision making about the type and intensity of care, and enables better understanding of provider performance. Methods MEDLINE and EMBASE were searched from January 1995 to March 2013, followed by hand searches of the retrieved reference lists. Studies were eligible if they reported at least 1 multivariable model for risk prediction of death, hospitalization, or both in patients with heart failure and reported model performance. We ranked reported individual risk predictors by their strength of association with the outcome and assessed the association of model performance with study characteristics. Results Sixty-four main models and 50 modifications from 48 studies met the inclusion criteria. Of the 64 main models, 43 models predicted death, 10 hospitalization, and 11 death or hospitalization. The discriminatory ability of the models for prediction of death appeared to be higher than that for prediction of death or hospitalization or prediction of hospitalization alone (p = 0.0003). A wide variation between studies in clinical settings, population characteristics, sample size, and variables used for model development was observed, but these features were not significantly associated with the discriminatory performance of the models. A few strong predictors emerged for prediction of death; the most consistently reported predictors were age, renal function, blood pressure, blood sodium level, left ventricular ejection fraction, sex, brain natriuretic peptide level, New York Heart Association functional class, diabetes, weight or body mass index, and exercise capacity. Conclusions There are several clinically useful and well-validated death prediction models in patients with heart failure. Although the studies differed in many respects, the models largely included a few common markers of risk

[O/Fe] Estimates for Carbon-Enhanced Metal-Poor Stars from Near-IR Spectroscopy

We report on oxygen abundances determined from medium-resolution near-IR spectroscopy for a sample of 57 carbon-enhanced metal-poor (CEMP) stars selected from the Hamburg/ESO survey. The majority of our program stars exhibit oxygen-to-iron ratios in the range +0.5 < [O/Fe]< +2.0. The [O/Fe] values for this sample are statistically compared to available high-resolution estimates for known CEMP stars, as well as to high-resolution estimates for a set of carbon-normal metal-poor stars. Carbon, nitrogen, and oxygen abundance patterns for a sub-sample of these stars are compared to yield predictions for very metal-poor asymptotic giant-branch abundances in the recent literature. We find that the majority of our sample exhibit patterns that are consistent with previously studied CEMP stars having s-process-element enhancements, and thus have very likely been polluted by carbon- and oxygen-enhanced material transferred from a metal-poor asymptotic giant-branch companion.Comment: 16 pages, 8 figures, accepted by A