Impact of ‘Stretch’ Targets for Cardiovascular Disease Management within a Local Pay-for-Performance Programme

Pay-for-performance programs are often aimed to improve the management of chronic diseases. We evaluate the impact of a local pay for performance programme (QOF+), which rewarded financially more ambitious quality targets (‘stretch targets’) than those used nationally in the Quality and Outcomes Framework (QOF). We focus on targets for intermediate outcomes in patients with cardiovascular disease and diabetes. A difference-in-difference approach is used to compare practice level achievements before and after the introduction of the local pay for performance program. In addition, we analysed patient-level data on exception reporting and intermediate outcomes utilizing an interrupted time series analysis. The local pay for performance program led to significantly higher target achievements (hypertension: p-value <0.001, coronary heart disease: p-values <0.001, diabetes: p-values <0.061, stroke: p-values <0.003). However, the increase was driven by higher rates of exception reporting (hypertension: p-value <0.001, coronary heart disease: p-values <0.03, diabetes: p-values <0.05) in patients with all conditions except for stroke. Exception reporting allows practitioners to exclude patients from target calculations if certain criteria are met, e.g. informed dissent of the patient for treatment. There were no statistically significant improvements in mean blood pressure, cholesterol or HbA1c levels. Thus, achievement of higher payment thresholds in the local pay for performance scheme was mainly attributed to increased exception reporting by practices with no discernable improvements in overall clinical quality. Hence, active monitoring of exception reporting should be considered when setting more ambitious quality targets. More generally, the study suggests a trade-off between additional incentive for better care and monitoring costs.     

Crotoxin from Crotalus durissus terrificus Is Able to Down-Modulate the Acute Intestinal Inflammation in Mice

Inflammatory bowel diseases (IBD) is the result of dysregulation of mucosal innate and adaptive immune responses. Factors such as genetic, microbial and environmental are involved in the development of these disorders. Accordingly, animal models that mimic human diseases are tools for the understanding the immunological processes of the IBD as well as to evaluate new therapeutic strategies. Crotoxin (CTX) is the main component of Crotalus durissus terrificus snake venom and has an immunomodulatory effect. Thus, we aimed to evaluate the modulatory effect of CTX in a murine model of colitis induced by 2,4,6- trinitrobenzene sulfonic acid (TNBS). The CTX was administered intraperitoneally 18 hours after the TNBS intrarectal instillation in BALB/c mice. The CTX administration resulted in decreased weight loss, disease activity index (DAI), macroscopic tissue damage, histopathological score and myeloperoxidase (MPO) activity analyzed after 4 days of acute TNBS colitis. Furthermore, the levels of TNF-α, IL-1β and IL-6 were lower in colon tissue homogenates of TNBS-mice that received the CTX when compared with untreated TNBS mice. The analysis of distinct cell populations obtained from the intestinal lamina propria showed that CTX reduced the number of group 3 innate lymphoid cells (ILC3) and Th17 population; CTX decreased IL-17 secretion but did not alter the frequency of CD4⁺Tbet⁺ T cells induced by TNBS instillation in mice. In contrast, increased CD4⁺FoxP3⁺ cell population as well as secretion of TGF-β, prostaglandin E₂ (PGE₂) and lipoxin A₄ (LXA₄) was observed in TNBS-colitis mice treated with CTX compared with untreated TNBS-colitis mice. In conclusion, the CTX is able to modulate the intestinal acute inflammatory response induced by TNBS, resulting in the improvement of clinical status of the mice. This effect of CTX is complex and involves the suppression of the pro-inflammatory environment elicited by intrarectal instillation of TNBS due to the induction of a local anti-inflammatory profile in mice.     

A Second Look at the Association between Gender and Mortality on Antiretroviral Therapy

Objective

We assessed the association between gender and mortality on antiretroviral therapy (ART) using identical models with and without sex-specific categories for weight and hemoglobin.

Design

Cohort study of adult patients on ART.

Setting

GHESKIO Clinic in Port-au-Prince, Haiti.

Participants

4,717 ART-naïve adult patients consecutively enrolled on ART at GHESKIO from 2003 to 2008.

Main Outcome Measure

Mortality on ART; multivariable analyses were conducted with and without sex-specific categories for weight and hemoglobin.

Results

In Haiti, male gender was associated with mortality (OR 1.61; 95% CI: 1.30–2.00) in multivariable analyses with hemoglobin and weight included as control variables, but not when sex-specific interactions with hemoglobin and weight were used.

Conclusions

If sex-specific categories are omitted, multivariable analyses indicate a higher risk of mortality for males vs. females of the same weight and hemoglobin. However, because males have higher normal values for weight and hemoglobin, the males in this comparison would generally have poorer health status than the females. This may explain why gender differences in mortality are sometimes observed after controlling for differences in baseline variables when gender-specific interactions with weight and hemoglobin are omitted.     

Pathogenic bacteria and timing of laying

Pathogenic bacteria constitute a serious threat to viability of many organisms. Because growth of most bacteria is favored by humid and warm environmental conditions, earlier reproducers in seasonal environments should suffer less from the negative consequences of pathogenic bacteria. These relationships, and the effects on reproductive success, should be particularly prominent in predators because they are frequently exposed to pathogenic microorganisms from sick prey. Here, we presented and tested this hypothesis by sampling bacteria on adult and nestling goshawks Accipiter gentilis. We predicted that early breeders and their offspring should have fewer bacteria than those reproducing later during the breeding season. Adult goshawks with a high abundance of Staphylococcus on their beak and claws were easier to capture and their laying date was delayed. Moreover, goshawks that laid their eggs later had offspring with more Staphylococcus on their beaks and claws. The strength of the association between laying date and bacterial density of nestlings was stronger during the warm spring of 2013, when nestlings suffered from a higher abundance of pathogenic bacteria. Hatching failure and fledging failure were more common in nests with a higher abundance of Staphylococcus independently of the number of years occupied, laying date, and age of the female nest owner. These findings imply that timing of reproduction may be under the influence of pathogenic bacteria. Because early breeding goshawks produce more recruits than later breeders, our results suggest a role for pathogenic bacteria in the optimal timing of reproduction.     

Increased oxidative stress in barn swallows from the Chernobyl region

The Chernobyl nuclear accident produced the largest unintended release of radionuclides in history, with dramatic consequences for humans and other organisms. Exposure to ionizing radiation is known to reduce circulating and stored levels of specific antioxidants in birds and humans, thus potentially increasing oxidative stress. However, overall effects of radioactive exposure on oxidative status have never been investigated in any free ranging vertebrate. We measured plasma antioxidant capacity and concentration of reactive oxygen metabolites in adult barn swallows (Hirundo rustica) from colonies with variable background radiation levels in the Chernobyl region in Ukraine and Belarus. We predicted that antioxidants would decrease while reactive oxygen metabolites would increase with exposure to increasing levels of radiation at the breeding sites. Consistent with this expectation, radiation level positively predicted plasma concentration of reactive oxygen metabolites, whereas no significant covariation was found with non-enzymatic plasma antioxidant capacity. An index of oxidative stress was also larger in barn swallows exposed to high contamination levels. Thus, radioactive contamination appeared to be responsible for the increased generation of reactive oxygen metabolites and the imbalance between reactive oxygen metabolites and non-enzymatic plasma antioxidant capacity.     

Using hyperspectral satellite imagery for regional inventories: a test with tropical emergent trees in the Amazon Basin

Questions: Understanding distributions of tree species at landscape scales in tropical forests is a difficult task that could benefit from the recent development of satellite imaging spectroscopy. We tested an application of the EO‐1 Hyperion satellite sensor to spectrally detect the location of five important tree taxa in the lowland humid tropical forests of southeastern Peru. Location: Peru, Departamento de Madre de Díos. Methods: We used linear discriminant analysis with a stepwise selection procedure to analyze two Hyperion datasets (July and December 2006) to choose the most informative narrow bands for classifying trees. Results: Optimal channels selected were different between the two seasons. Classification was 100% successful for the five taxa when using 25 narrow bands and pixels that represented >40% of tree crowns. We applied the discriminant functions developed separately for the two seasons to the entire study area, and found significantly nonrandom overlap in the anticipated distributions of the five taxa between seasons. Conclusions: Despite known issues, such as signal‐to‐noise ratio and spatial resolution, Hyperion imaging spectroscopy has potential for developing regional mapping of large‐crowned tropical trees.     

Levels of antioxidants in rural and urban birds and their consequences

Numerous animals have successfully invaded urban habitats, although the factors associated with invasion success remain poorly understood. Urban areas are characterized by warmer microclimates, higher levels of primary productivity, longer breeding seasons and higher levels of pollutants. All these factors should cause oxidative stress, favoring invasion by species that have access to high levels of antioxidants. We analyzed concentrations of two categories of dietary, fat-soluble antioxidants (total carotenoids, total vitamin E) in the liver, the main storage organ in birds. Individuals killed by cats had lower levels of vitamin E than individuals that died for other reasons, showing natural selection on stored antioxidants. Bird species that had successfully colonized urban areas had significantly higher levels of vitamin E and total carotenoids than species that did not succeed, and rural populations had higher concentrations of vitamin E and total carotenoids than urban populations of the same species. Interspecific differences in concentrations of fat-soluble antioxidants, and differences between rural and urban populations of the same species, were accounted for by diet, but also by time since urbanization and number of generations since urbanization. These findings suggest that antioxidants, and by implication the ability to cope with oxidative stress, have contributed to successful invasion of urban areas by birds, and that the concentration of these antioxidants has changed in response to the urban environment.     

Characterization of Plant Carotenoid Cyclases as Members of the Flavoprotein Family Functioning with No Net Redox Change

The later steps of carotenoid biosynthesis involve the formation of cyclic carotenoids. The reaction is catalyzed by lycopene β-cyclase (LCY-B), which converts lycopene into β-carotene, and by capsanthin-capsorubin synthase (CCS), which is mainly dedicated to the synthesis of κ-cyclic carotenoids (capsanthin and capsorubin) but also has LCY-B activity. Although the peptide sequences of plant LCY-Bs and CCS contain a putative dinucleotide-binding motif, it is believed that these two carotenoid cyclases proceed via protic activation and stabilization of resulting carbocation intermediates. Using pepper (Capsicum annuum) CCS as a prototypic carotenoid cyclase, we show that the monomeric protein contains one noncovalently bound flavin adenine dinucleotide (FAD) that is essential for enzyme activity only in the presence of NADPH, which functions as the FAD reductant. The reaction proceeds without transfer of hydrogen from the dinucleotide cofactors to β-carotene or capsanthin. Using site-directed mutagenesis, amino acids potentially involved in the protic activation were identified. Substitutions of alanine, lysine, and arginine for glutamate-295 in the conserved 293-FLEET-297 motif of pepper CCS or LCY-B abolish the formation of β-carotene and κ-cyclic carotenoids. We also found that mutations of the equivalent glutamate-196 located in the 194-LIEDT-198 domain of structurally divergent bacterial LCY-B abolish the formation of β-carotene. The data herein reveal plant carotenoid cyclases to be novel enzymes that combine characteristics of non-metal-assisted terpene cyclases with those attributes typically found in flavoenzymes that catalyze reactions, with no net redox, such as type 2 isopentenyl diphosphate isomerase. Thus, FAD in its reduced form could be implicated in the stabilization of the carbocation intermediate.Later steps of carotenoid biosynthesis involve the formation of diverse cyclic carotenoids. For example, β-carotene, the vitamin A precursor, is synthesized de novo by photosynthetic organisms, limited nonphototrophic bacteria and fungi, and also by aphids (Moran and Jarvik, 2010) according to a multistep pathway that ends with the cyclization of lycopene by lycopene β-cyclase (LCY-B). Similarly, in pepper (Capsicum annuum) chromoplasts, antheraxanthin and violaxanthin are converted into the κ-cyclic carotenoids capsanthin and capsorubin, respectively, by capsanthin-capsorubin synthase (CCS). In both cases, the proposed mechanism involves a concerted protic attack and stabilization of a transient carbocation without any net redox change (Camara, 1980; Bouvier et al., 1994; Britton, 1998). Several cDNAs for LCY-B have been cloned from bacteria (Misawa et al., 1990; Cunningham et al., 1994; Armstrong, 1997; Cunningham and Gantt, 2001), fungi (Verdoes et al., 1999; Velayos et al., 2000; Arrach et al., 2001), and plants (Hugueney et al., 1995; Ronen et al., 2000) using functional complementation. Information available from primary structures suggest that the cyclization of lycopene is catalyzed by holomeric proteins in photosynthetic organisms (Cunningham et al., 1994; Maresca et al., 2007), by holomeric (Misawa et al., 1990) or heteromeric (Krubasik and Sandmann, 2000; Viveiros et al., 2000) proteins in nonphotosynthetic bacteria, and by holomeric, bifunctional proteins in fungi that combine the activities of phytoene synthase and lycopene cyclase (Verdoes et al., 1999; Velayos et al., 2000; Arrach et al., 2001). This structural diversity of LCY-Bs coupled to a lack of significant amino acid sequence identity between the lycopene cyclases from bacteria, fungi, and plants hinder our understanding of the catalytic mechanism of LCY-Bs and CCS. In addition, the N terminus of plant LCY-B and CCS contains an amino sequence motif characteristic of a polypeptide predicted to adopt a Rossmann fold (Rossmann et al., 1974) and suggests the binding of an as yet unknown dinucleotide prosthetic ligand. It has been shown using recombinant bacterial enzyme that the cyclization of lycopene into β-carotene strictly requires NADPH but proceeds without any net redox change (Schnurr et al., 1996; Hornero-Mendez and Britton, 2002). Under the same conditions, FAD alone could not sustain bacterial LCY-B activity (Schnurr et al., 1996). Much less is known about the dinucleotide requirements of plant carotenoid cyclases, which are highly conserved within plants but are extremely divergent in nonplant organisms. Previously, a crucial acidic domain for lycopene cyclase activity was identified using an affinity-labeling strategy followed by site-directed mutagenesis (Bouvier et al., 1997) in the absence of any crystal structures. This so-called 293-FLEET-297 motif of LCY-B and CCS contained two tandem Glu-295-Glu-296 residues that were essential for LCY-B- and κ-cyclase activities (Bouvier et al., 1997). However, it still remains unclear how the protic mechanism is compatible with the requirement of dinucleotide cofactors.To further explore the mechanism of plant carotenoid cyclases, we first choose pepper CCS as a prototypic enzyme because it displays a strong identity (52%) to pepper LCY-B, and we have shown previously that CCS could also catalyze the cyclization of lycopene into β-carotene (up to 25% of activity compared with LCY-B; Hugueney et al., 1995). Herein, we have shown that monomeric CCS purified to homogeneity from plant chromoplasts or recombinant CCS purified from Escherichia coli-transformed cells are typical flavoproteins containing one noncovalently bound FAD. We also observed that CCS-bound FAD is required for enzyme activity in the presence of NADPH, which functions as a reductant of FAD. During this process, no hydrogen is transferred to β-carotene or κ-cyclic carotenoids. In addition to this cofactor requirement, we also show from extensive site-directed mutagenesis using pepper CCS and LCY-B and Erwinia herbicola LCY-B (Mialoundama, 2009) that Glu-295 of pepper CCS and LCY-B plays a key role in the formation of β-carotene and κ-cyclic carotenoids, and we demonstrate that a similar role is played in structurally divergent bacterial LCY-Bs by Glu-196. These characteristics suggest that plant CCS and LCY-Bs are mechanistically similar to non-metal-assisted terpene cyclases, such as squalene:hopene cyclase and oxidosqualene cyclase, and additionally represent a new subfamily of flavoproteins like isopentenyl diphosphate isomerase type II, which catalyze carotenoid cyclization without any net redox modification of the substrate.     

Inhibition of lycopene cyclization by Capsicum chromoplast membranes by 2-aza-2,3-dihydrosqualene

2-Aza-2,3-dihydrosqualene strongly inhibited lycopene cyclase from Capsicum chromoplast membranes.