Peroxiredoxin Catalysis at Atomic Resolution

Peroxiredoxins (Prxs) are ubiquitous cysteine-based peroxidases that guard cells against oxidative damage, are virulence factors for pathogens, and are involved in eukaryotic redox regulatory pathways. We have analyzed catalytically active crystals to capture atomic resolution snapshots of a PrxQ-subfamily enzyme (from Xanthomonas campestris) proceeding through thiolate, sulfenate, and sulfinate species. These analyses provide structures of unprecedented accuracy for seeding theoretical studies, and show novel conformational intermediates giving insight into the reaction pathway. Based on a highly non-standard geometry seen for the sulfenate intermediate, we infer that the sulfenate formation itself can strongly promote local unfolding of the active site to enhance productive catalysis. Further, these structures reveal that preventing local unfolding, in this case via crystal contacts, results in facile hyperoxidative inactivation even for Prxs normally resistant to such inactivation. This supports previous proposals that conformation-specific inhibitors may be useful for achieving selective inhibition of Prxs that are drug targets

Specific Control of Pseudomonas aeruginosa Surface-Associated Behaviors by Two c-di-GMP Diguanylate Cyclases

The signaling nucleotide cyclic diguanylate (c-di-GMP) regulates the transition between motile and sessile growth in a wide range of bacteria. Understanding how microbes control c-di-GMP metabolism to activate specific pathways is complicated by the apparent multifold redundancy of enzymes that synthesize and degrade this dinucleotide, and several models have been proposed to explain how bacteria coordinate the actions of these many enzymes. Here we report the identification of a diguanylate cyclase (DGC), RoeA, of Pseudomonas aeruginosa that promotes the production of extracellular polysaccharide (EPS) and contributes to biofilm formation, that is, the transition from planktonic to surface-dwelling cells. Our studies reveal that RoeA and the previously described DGC SadC make distinct contributions to biofilm formation, controlling polysaccharide production and flagellar motility, respectively. Measurement of total cellular levels of c-di-GMP in ∆roeA and ∆sadC mutants in two different genetic backgrounds revealed no correlation between levels of c-di-GMP and the observed phenotypic output with regard to swarming motility and EPS production. Our data strongly argue against a model wherein changes in total levels of c-di-GMP can account for the specific surface-related phenotypes of P. aeruginosa

"We can't expect much": Childbearing women's 'horizon of expectations' of the health system in rural Vietnam.

Highlights • Responsiveness centres on understanding peoples' ‘legitimate’ expectations of their health system. • Healthcare-related expectations are shaped at the intersection of social, temporal, and spatial ‘locations’. • Expectations are also shaped by social norms, and market-driven practices and forces in the health system. • There is a need for health system actors to consider the impact of market forces on responsive care provision. • Active citizen participation and contestation is also needed to establish ‘legitimate’ expectations of care

Detection of circulating tumour DNA is associated with inferior outcomes in Ewing sarcoma and osteosarcoma: a report from the Children's Oncology Group.

BackgroundNew prognostic markers are needed to identify patients with Ewing sarcoma (EWS) and osteosarcoma unlikely to benefit from standard therapy. We describe the incidence and association with outcome of circulating tumour DNA (ctDNA) using next-generation sequencing (NGS) assays.MethodsA NGS hybrid capture assay and an ultra-low-pass whole-genome sequencing assay were used to detect ctDNA in banked plasma from patients with EWS and osteosarcoma, respectively. Patients were coded as positive or negative for ctDNA and tested for association with clinical features and outcome.ResultsThe analytic cohort included 94 patients with EWS (82% from initial diagnosis) and 72 patients with primary localised osteosarcoma (100% from initial diagnosis). ctDNA was detectable in 53% and 57% of newly diagnosed patients with EWS and osteosarcoma, respectively. Among patients with newly diagnosed localised EWS, detectable ctDNA was associated with inferior 3-year event-free survival (48.6% vs. 82.1%; p = 0.006) and overall survival (79.8% vs. 92.6%; p = 0.01). In both EWS and osteosarcoma, risk of event and death increased with ctDNA levels.ConclusionsNGS assays agnostic of primary tumour sequencing results detect ctDNA in half of the plasma samples from patients with newly diagnosed EWS and osteosarcoma. Detectable ctDNA is associated with inferior outcomes

HMU fluorinze mouthwash enhances enamel remineralization: An in vitro study

BACKGROUND: Fluoride therapy has long been used extensively to prevent dental caries. Fluoride appears in variety of dental care products such as mouthrinse, dentifrice, gel, etc. HMU fluorinze is the first mouthwash containing fluoride in Vietnam. AIM: This research was conducted to evaluate the efficacy of HMU Fluorinze mouthwash on remineralizing enamel in laboratory conditions. METHODS: 20 third molars teeth were cleaned and covered with nail polish , except for a 3x3 mm square on their buccal surfaces. These teeth went through two steps: demineralization using Coke and remineralization for 20 days: 1) using standard calcifying solution (control group) and 2) using standard calcifying solution + HMU Fluorinze mouthwash 2 times/day (experimental group). The mineralization index of enamel structure after demineralization and remineralization was assessed by DIAGNOdent pen 2190. RESULTS: The mineralization indexes of the control group and experimental group at baseline were 3.65 ± 0.76 and 3.35 ± 0.64, after demineralization were in turn of 21.78 ± 4.48 and 20.25 ± 2.26; and after remineralization were 6.30 ± 1.03 and 3.90 ± 1.24. The different figures  between the two groups after remineralization shows statistical significance (p<0.01). Group B using HMU fluorinze mouthwash after 20 days did not differ from the original results (p = 0.272), in contrast with the control group (p<0.01). CONCLUSIONS: HMU fluorinze mouthwash has better mineralization effect than standard calcifying solution

Expression of Regulatory Platelet MicroRNAs in Patients with Sickle Cell Disease

Background: Increased platelet activation in sickle cell disease (SCD) contributes to a state of hypercoagulability and confers a risk of thromboembolic complications. The role for post-transcriptional regulation of the platelet transcriptome by microRNAs (miRNAs) in SCD has not been previously explored. This is the first study to determine whether platelets from SCD exhibit an altered miRNA expression profile. Methods and Findings: We analyzed the expression of miRNAs isolated from platelets from a primary cohort (SCD = 19, controls = 10) and a validation cohort (SCD = 7, controls = 7) by hybridizing to the Agilent miRNA microarrays. A dramatic difference in miRNA expression profiles between patients and controls was noted in both cohorts separately. A total of 40 differentially expressed platelet miRNAs were identified as common in both cohorts (p-value 0.05, fold change>2) with 24 miRNAs downregulated. Interestingly, 14 of the 24 downregulated miRNAs were members of three families - miR-329, miR-376 and miR-154 - which localized to the epigenetically regulated, maternally imprinted chromosome 14q32 region. We validated the downregulated miRNAs, miR-376a and miR-409-3p, and an upregulated miR-1225-3p using qRT-PCR. Over-expression of the miR-1225-3p in the Meg01 cells was followed by mRNA expression profiling to identify mRNA targets. This resulted in significant transcriptional repression of 1605 transcripts. A combinatorial approach using Meg01 mRNA expression profiles following miR-1225-3p overexpression, a computational prediction analysis of miRNA target sequences and a previously published set of differentially expressed platelet transcripts from SCD patients, identified three novel platelet mRNA targets: PBXIP1, PLAGL2 and PHF20L1. Conclusions: We have identified significant differences in functionally active platelet miRNAs in patients with SCD as compared to controls. These data provide an important inventory of differentially expressed miRNAs in SCD patients and an experimental framework for future studies of miRNAs as regulators of biological pathways in platelets. © 2013 Jain et al

Identifying and characterizing COPD patients in US managed care. A retrospective, cross-sectional analysis of administrative claims data

<p>Abstract</p> <p>Background</p> <p>Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death among US adults and is projected to be the third by 2020. In anticipation of the increasing burden imposed on healthcare systems and payers by patients with COPD, a means of identifying COPD patients who incur higher healthcare utilization and costs is needed.</p> <p>Methods</p> <p>This retrospective, cross-sectional analysis of US managed care administrative claims data describes a practical way to identify COPD patients. We analyze 7.79 million members for potential inclusion in the COPD cohort, who were continuously eligible during a 1-year study period. A younger commercial population (7.7 million) is compared with an older Medicare population (0.115 million). We outline a novel approach to stratifying COPD patients using "complexity" of illness, based on occurrence of claims for given comorbid conditions. Additionally, a unique algorithm was developed to identify and stratify COPD exacerbations using claims data.</p> <p>Results</p> <p>A total of 42,565 commercial (median age 56 years; 51.4% female) and 8507 Medicare patients (median 75 years; 53.1% female) were identified as having COPD. Important differences were observed in comorbidities between the younger commercial versus the older Medicare population. Stratifying by complexity, 45.0%, 33.6%, and 21.4% of commercial patients and 36.6%, 35.8%, and 27.6% of older patients were low, moderate, and high, respectively. A higher proportion of patients with high complexity disease experienced multiple (≥2) exacerbations (61.7% commercial; 49.0% Medicare) than patients with moderate- (56.9%; 41.6%), or low-complexity disease (33.4%; 20.5%). Utilization of healthcare services also increased with an increase in complexity.</p> <p>Conclusion</p> <p>In patients with COPD identified from Medicare or commercial claims data, there is a relationship between complexity as determined by pulmonary and non-pulmonary comorbid conditions and the prevalence of exacerbations and utilization of healthcare services. Identification of COPD patients at highest risk of exacerbations using complexity stratification may facilitate improved disease management by targeting those most in need of treatment.</p

Febrile Illness Management in Children under Five Years of Age: A Qualitative Pilot Study on Primary Health Care Workers' Practices in Zanzibar.

In Zanzibar, malaria prevalence dropped substantially in the last decade and presently most febrile patients seen in primary health care facilities (PHCF) test negative for malaria. The availability of rapid diagnostic tests (RDTs) allows rural health workers to reliably rule out malaria in fever patients. However, additional diagnostic tools to identify alternative fever causes are scarce, often leaving RDT-negative patients without a clear diagnosis and management plan. This pilot study aimed to explore health workers' practices with febrile children and identify factors influencing their diagnostic and management decisions in non-malarial fever patients. Semi-structured key informant interviews were conducted with 12 health workers in six PHCFs in North A district, Zanzibar, April to June 2011. Interviews were coded using Atlas.ti to identify emerging themes that play a role in the diagnosis and management of febrile children. The following themes were identified: 1) health workers use caregivers' history of illness and RDT results for initial diagnostic and management decisions, but suggest caregivers need more education to prevent late presentation and poor health outcomes; 2) there is uncertainty regarding viral versus bacterial illness and health workers feel additional point-of-care diagnostic tests would help with differential diagnoses; 3) stock-outs of medications and limited caregivers' resources are barriers to delivering good care; 4) training, short courses and participation in research as well as; 5) weather also influences diagnostic decision-making. This pilot study found that health workers in Zanzibar use caregiver history of fever and results of malaria RDTs to guide management of febrile children. However, since most febrile children test negative for malaria, health workers believe additional training and point-of-care tests would improve their ability to diagnose and manage non-malarial fevers. Educating caregivers on signs and symptoms of febrile illness, as well as the introduction of additional tests to differentiate between viral and bacterial illness, would be important steps to get children to PHCFs earlier and decrease unnecessary antibiotic prescribing without compromising patient safety. More research is needed to expand an understanding of what would improve fever management in other resource-limited settings with decreasing malaria

Upper extremity impairments in women with or without lymphedema following breast cancer treatment

Breast-cancer-related lymphedema affects ∼25% of breast cancer (BC) survivors and may impact use of the upper limb during activity. The purpose of this study is to compare upper extremity (UE) impairment and activity between women with and without lymphedema after BC treatment. 144 women post BC treatment completed demographic, symptom, and Disability of Arm-Shoulder-Hand (DASH) questionnaires. Objective measures included Purdue pegboard, finger-tapper, Semmes-Weinstein monofilaments, vibration perception threshold, strength, range of motion (ROM), and volume. Women with lymphedema had more lymph nodes removed (p &lt; .001), more UE symptoms (p &lt; .001), higher BMI (p = .041), and higher DASH scores (greater limitation) (p &lt; .001). For all participants there was less strength (elbow flexion, wrist flexion, grip), less shoulder ROM, and decreased sensation at the medial upper arm (p &lt; .05) in the affected UE. These differences were greater in women with lymphedema, particularly in shoulder abduction ROM (p &lt; .05). Women with lymphedema had bilaterally less elbow flexion strength and shoulder ROM (p &lt; .05). Past diagnosis of lymphedema, grip strength, shoulder abduction ROM, and number of comorbidities contributed to the variance in DASH scores (R 2 of 0.463, p &lt; .001). UE impairments are found in women following treatment for BC. Women with lymphedema have greater UE impairment and limitation in activities than women without. Many of these impairments are amenable to prevention measures or treatment, so early detection by health care providers is essential