249 research outputs found

    Use of Prostate-specific Antigen Testing in Medicare Beneficiaries: Association with Previous Evaluation

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    Objective: Determine uptake of prostate-specific antigen (PSA) testing in Medicare beneficiaries according to previous receipt of PSA testing. Methods: A 5% random sample of men aged 67 years or older without a previous diagnosis of prostate cancer was identified through 2009-2012 Medicare claims. We measured the annualized frequency of PSA screening among men due for PSA testing, stratified by PSA testing use in the previous 2 years, and clustered by ordering provider. Results: Throughout the study period, PSA testing use was consistently higher for men with previous screening than for men without previous screening. For men without previous screening, there was a decline in testing that was most pronounced in 2012. Compared with 2009, the corresponding odds ratios were 0.98 [95% confidence interval (CI) (0.96-1.00)] in 2010, 0.94 [95% CI (0.92-0.95)] in 2011, and 0.66 [95% CI (0.65-0.68)] in 2012. In contrast, for men with previous screening, PSA testing frequency was stable from 2009 to 2011, and declined to a lesser extent in 2012 [odds ratio 0.80, 95% CI (0.79-0.81)]. Conclusion: Receipt of PSA testing is highly dependent on whether an individual was tested in the recent past. In previously unscreened men, the largest decrease occurred in 2012, which may reflect in part the publication of US Preventive Services Task Force guidelines, but there was much less impact among men already being screened. © 2017 Family Medicine and Community Health

    The Roles of the Chaperone-like Protein CpeZ and the Phycoerythrobilin Lyase CpeY in Phycoerythrin Biogenesis

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    Phycoerythrin (PE) present in the distal ends of light-harvesting phycobilisome rods in Fremyella diplosiphon (Tolypothrix sp. PCC 7601) contains five phycoerythrobilin (PEB) chromophores attached to six cysteine residues for efficient green light capture for photosynthesis. Chromophore ligation on PE subunits occurs through bilin lyase catalyzed reactions, but the characterization of the roles of all bilin lyases for phycoerythrin is not yet complete. To gain a more complete understanding about the individual functions of CpeZ and CpeY in PE biogenesis in cyanobacteria, we examined PE and phycobilisomes purified from wild type F. diplosiphon, cpeZ and cpeY knockout mutants. We find that the cpeZ and cpeY mutants accumulate less PE than wild type cells. We show that in the cpeZ mutant, chromophorylation of both PE subunits is affected, especially the Cys-80 and Cys-48/Cys-59 sites of CpeB, the beta-subunit of PE. The cpeY mutant showed reduced chromophorylation at Cys-82 of CpeA. We also show that, in vitro, CpeZ stabilizes PE subunits and assists in refolding of CpeB after denaturation. Taken together, we conclude that CpeZ acts as a chaperone-like protein, assisting in the folding/stability of PE subunits, allowing bilin lyases such as CpeY and CpeS to attach PEB to their PE subunit

    CpeT is the Phycoerythrobilin Lyase for Cys-165 on Beta-Phycoerythrin from Fremyella Diplosiphon and the Chaperone-like Protein CpeZ Greatly Improves its Activity.

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    Bilin lyases are enzymes which ligate linear tetrapyrrole chromophores to specific cysteine residues on light harvesting proteins present in cyanobacteria and red algae. The lyases responsible for chromophorylating the light harvesting protein phycoerythrin (PE) have not been fully characterized. In this study, we explore the role of CpeT, a putative bilin lyase, in the biosynthesis of PE in the cyanobacterium Fremyella diplosiphon. Recombinant protein studies show that CpeT alone can bind phycoerythrobilin (PEB), but CpeZ, a chaperone-like protein, is needed in order to correctly and efficiently attach PEB to the beta-subunit of PE. MS analyses of the recombinant beta-subunit of PE coexpressed with CpeT and CpeZ show that PEB is attached at Cys-165. Purified phycobilisomes from a cpeT knockout mutant and wild type (WT) samples from F. diplosiphon were analyzed and compared. The cpeT mutant contained much less PE and more phycocyanin than WT cells grown under green light, conditions which should maximize the production of PE. In addition, Northern blot analyses showed that the cpeCDESTR operon mRNAs were upregulated while the cpeBcpeA mRNAs were downregulated in the cpeT mutant strain when compared with WT, suggesting that CpeT may also play a direct or indirect regulatory role in transcription of these operons or their mRNA stability, in addition to its role as a PEB lyase for Cys-165 on beta-PE

    Interplay Between Differentially Expressed Enzymes Contributes to Light Color Acclimation in Marine Synechococcus

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    Marine Synechococcus, a globally important group of cyanobacteria, thrives in various light niches in part due to its varied photosynthetic light-harvesting pigments. Many Synechococcus strains use a process known as chromatic acclimation to optimize the ratio of two chromophores, green-light-absorbing phycoerythrobilin (PEB) and blue-light-absorbing phycourobilin (PUB), within their light-harvesting complexes. A full mechanistic understanding of how Synechococcus cells tune their PEB to PUB ratio during chromatic acclimation has not yet been obtained. Here, we show that interplay between two enzymes named MpeY and MpeZ controls differential PEB and PUB covalent attachment to the same cysteine residue. MpeY attaches PEB to the light-harvesting protein MpeA in green light, while MpeZ attaches PUB to MpeA in blue light. We demonstrate that the ratio of mpeY to mpeZ mRNA determines if PEB or PUB is attached. Additionally, strains encoding only MpeY or MpeZ do not acclimate. Examination of strains of Synechococcus isolated from across the globe indicates that the interplay between MpeY and MpeZ uncovered here is a critical feature of chromatic acclimation for marine Synechococcus worldwide

    CpeF is the Bilin Lyase that Ligates the Doubly Linked Phycoerythrobilin on Phycoerythrin in the Cyanobacterium Fremyella Diplosiphon

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    Phycoerythrin (PE) is a green light-absorbing protein present in the light-harvesting complex of cyanobacteria and red algae. The spectral characteristics of PE are due to its prosthetic groups, or phycoerythrobilins (PEBs), that are covalently attached to the protein chain by specific bilin lyases. Only two PE lyases have been identified and characterized so far, and the other bilin lyases are unknown. Here, using in silico analyses, markerless deletion, biochemical assays with purified and recombinant proteins, and site-directed mutagenesis, we examined the role of a putative lyase-encoding gene, cpeF, in the cyanobacterium Fremyella diplosiphon. Analyzing the phenotype of the cpeF deletion, we found that cpeF is required for proper PE biogenesis, specifically for ligation of the doubly linked PEB to Cys-48/Cys-59 residues of the CpeB subunit of PE. We also show that in a heterologous host, CpeF can attach PEB to Cys-48/Cys-59 of CpeB, but only in the presence of the chaperone-like protein CpeZ. Additionally, we report that CpeF likely ligates the A ring of PEB to Cys-48 prior to the attachment of the D ring to Cys-59. We conclude that CpeF is the bilin lyase responsible for attachment of the doubly ligated PEB to Cys-48/Cys-59 of CpeB and together with other specific bilin lyases contributes to the post-translational modification and assembly of PE into mature light-harvesting complexes

    Correlation of high levels of antibodies to multiple pre-erythrocytic Plasmodium falciparum antigens and protection from infection

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    High levels of antibodies to multiple antigens may be more strongly associated with protection from infection than antibodies to a single antigen. Antibody-associated protection against Plasmodium falciparum infection was assessed in a cohort of 68 adults living in an area of holoendemic malaria in Kenya. Antibodies to the pre-erythrocytic antigens circumsporozoite protein (CSP), liver-stage antigen-1 (LSA-1), thrombospondin-related adhesive protein (TRAP), and blood-stage antigens apical membrane antigen-1 (AMA-1), erythrocyte binding antigen-175 (EBA-175), and merozoite surface protein 1 (MSP-1) were tested. Peptides were used for CSP (NANP repeat) and LSA-1 (central repeat), and recombinant antigens were used for TRAP (aa D(48)-K(394)), AMA-1 (ectodomain, non-glycosylated), EBA-175 (non-glycosylated), and MSP-1 (MSP-1(19)). Weekly microscopy testing for P. falciparum infection was performed over a 12-week period after drug-mediated clearance of P. falciparum parasitemia. Individuals with high levels of IgG antibodies (\u3e 2 arbitrary units) to CSP, LSA-1, and TRAP had a 57% decrease in the risk of infection (95% confidence interval = 20-77%, P = 0.016). This decreased risk remained significant after adjustment for age, prior parasitemia, bed net use, sickle cell trait, and village of residence. In contrast, protection against infection did not correlate with high levels of IgG antibodies to blood-stage antigens or IgM antibodies to pre-erythrocytic or blood-stage antigens. High levels of IgG antibodies to CSP, LSA-1, and TRAP may be useful immune correlates of protection against P. falciparum infection in malaria-endemic populations

    Cargo Cults in Information Systems Development: a Definition and an Analytical Framework

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    Organizations today adopt agile information systems development methods (ISDM), but many do not succeed with the adoption process and in achieving desired results. Systems developers sometimes fail in efficient use of ISDM, often due to a lack of understanding the fundamental intentions of the chosen method. In many cases organizations simply imitate the behavior of others without really understanding why. This conceptual paper defines this phenomenon as an ISDM cargo cult behavior and proposes an analytical framework to identify such situations. The concept of cargo cults originally comes from the field of social anthropology and has been used to explain irrational, ritualistic imitation of certain behavior. By defining and introducing the concept in the field of information systems development we provide a diagnostic tool to better understand one of the reasons why ISDM adoption sometimes fail

    Genetic modifiers of lung disease in cystic fibrosis

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    BACKGROUND: Polymorphisms in genes other than the cystic fibrosis transmembrane conductance regulator (CFTR) gene may modify the severity of pulmonary disease in patients with cystic fibrosis. METHODS: We performed two studies with different patient samples. We first tested 808 patients who were homozygous for the ΔF508 mutation and were classified as having either severe or mild lung disease, as defined by the lowest or highest quartile of forced expiratory volume in one second (FEV 1), respectively, for age. We genotyped 16 polymorphisms in 10 genes reported by others as modifiers of disease severity in cystic fibrosis and tested for an association in patients with severe disease (263 patients) or mild disease (545). In the replication (second) study, we tested 498 patients, with various CFTR genotypes and a range of FEV 1 values, for an association of the TGFβ1 codon 10 CC genotype with low FEV 1. RESULTS: In the initial study, significant allelic and genotypic associations with phenotype were seen only for TGFβ1 (the gene encoding transforming growth factor β1), particularly the -509 and codon 10 polymorphisms (with P values obtained with the use of Fisher's exact test and logistic regression ranging from 0.006 to 0.0002). The odds ratio was about 2.2 for the highest-risk TGFβ1 genotype (codon 10 CC) in association with the phenotype for severe lung disease. The replication study confirmed the association of the TGFβ1 codon 10 CC genotype with more severe lung disease in comparisons with the use of dichotomized FEV 1 for severity status (P=0.0002) and FEV 1 values directly (P=0.02). CONCLUSIONS: Genetic variation in the 5′ end of TGFβ1 or a nearby upstream region modifies disease severity in cystic fibrosis
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