Characterization of Schistosome Tegumental Alkaline Phosphatase (SmAP)

Schistosomes are parasitic platyhelminths that currently infect over 200 million people globally. The parasites can live for years in a putatively hostile environment - the blood of vertebrates. We have hypothesized that the unusual schistosome tegument (outer-covering) plays a role in protecting parasites in the blood; by impeding host immunological signaling pathways we suggest that tegumental molecules help create an immunologically privileged environment for schistosomes. In this work, we clone and characterize a schistosome alkaline phosphatase (SmAP), a predicted ∼60 kDa glycoprotein that has high sequence conservation with members of the alkaline phosphatase protein family. The SmAP gene is most highly expressed in intravascular parasite life stages. Using immunofluorescence and immuno-electron microscopy, we confirm that SmAP is expressed at the host/parasite interface and in internal tissues. The ability of living parasites to cleave exogenous adenosine monophosphate (AMP) and generate adenosine is very largely abolished when SmAP gene expression is suppressed following RNAi treatment targeting the gene. These results lend support to the hypothesis that schistosome surface enzymes such as SmAP could dampen host immune responses against the parasites by generating immunosuppressants such as adenosine to promote their survival. This notion does not rule out other potential functions for the adenosine generated e.g. in parasite nutrition

Recent improvements in the development of A2B adenosine receptor agonists

Adenosine is known to exert most of its physiological functions by acting as local modulator at four receptor subtypes named A1, A2A, A2B and A3 (ARs). Principally as a result of the difficulty in identifying potent and selective agonists, the A2B AR is the least extensively characterised of the adenosine receptors family. Despite these limitations, growing understanding of the physiological meaning of this target indicates promising therapeutic perspectives for specific ligands. As A2B AR signalling seems to be associated with pre/postconditioning cardioprotective and anti-inflammatory mechanisms, selective agonists may represent a new therapeutic group for patients suffering from coronary artery disease. Herein we present an overview of the recent advancements in identifying potent and selective A2B AR agonists reported in scientific and patent literature. These compounds can be classified into adenosine-like and nonadenosine ligands. Nucleoside-based agonists are the result of modifying adenosine by substitution at the N6-, C2-positions of the purine heterocycle and/or at the 5′-position of the ribose moiety or combinations of these substitutions. Compounds 1-deoxy-1-{6-[N′-(furan-2-carbonyl)-hydrazino]-9H-purin-9-yl}-N-ethyl-β-D-ribofuranuronamide (19, hA1Ki = 1050 nM, hA2AKi = 1550 nM, hA2B EC50 = 82 nM, hA3Ki > 5 μM) and its 2-chloro analogue 23 (hA1Ki = 3500 nM, hA2AKi = 4950 nM, hA2B EC50 = 210 nM, hA3Ki > 5 μM) were confirmed to be potent and selective full agonists in a cyclic adenosine monophosphate (cAMP) functional assay in Chinese hamster ovary (CHO) cells expressing hA2B AR. Nonribose ligands are represented by conveniently substituted dicarbonitrilepyridines, among which 2-[6-amino-3,5-dicyano-4-[4-(cyclopropylmethoxy)phenyl]pyridin-2-ylsulfanyl]acetamide (BAY-60–6583, hA1, hA2A, hA3 EC50 > 10 μM; hA2B EC50 = 3 nM) is currently under preclinical-phase investigation for treating coronary artery disorders and atherosclerosis

Patient safety management from the perspective of nurses

OBJECTIVE To evaluate the actions of patient safety management developed in hospitals, from the perspective of nurses. METHOD This is a cross-sectional, descriptive study of the survey type. Participants were seven hospitals, in which seven nurse managers and 49 sector coordinator nurses (n = 56) answered the instrument prepared by the author. RESULTS The results showed that 100% of hospitals have an adverse event reporting system, 71.4% have a Risk Management Committee and 80% have discussions about the events. There is agreement that these discussions lead to favorable changes for patient safety in the surveyed institutions. The employees' fear of punishment for their faults, and the underreporting of events were the aspects of greatest weakness found. CONCLUSION The institutions should develop organizational policies focused on stimulating event notification and on the implementation of measures directed to a non-punitive organizational culture

Purinergic signalling links mechanical breath profile and alveolar mechanics with the pro-inflammatory innate immune response causing ventilation-induced lung injury

Severe pulmonary infection or vigorous cyclic deformation of the alveolar epithelial type I (AT I) cells by mechanical ventilation leads to massive extracellular ATP release. High levels of extracellular ATP saturate the ATP hydrolysis enzymes CD39 and CD73 resulting in persistent high ATP levels despite the conversion to adenosine. Above a certain level, extracellular ATP molecules act as danger-associated molecular patterns (DAMPs) and activate the pro-inflammatory response of the innate immunity through purinergic receptors on the surface of the immune cells. This results in lung tissue inflammation, capillary leakage, interstitial and alveolar oedema and lung injury reducing the production of surfactant by the damaged AT II cells and deactivating the surfactant function by the concomitant extravasated serum proteins through capillary leakage followed by a substantial increase in alveolar surface tension and alveolar collapse. The resulting inhomogeneous ventilation of the lungs is an important mechanism in the development of ventilation-induced lung injury. The high levels of extracellular ATP and the upregulation of ecto-enzymes and soluble enzymes that hydrolyse ATP to adenosine (CD39 and CD73) increase the extracellular adenosine levels that inhibit the innate and adaptive immune responses rendering the host susceptible to infection by invading microorganisms. Moreover, high levels of extracellular adenosine increase the expression, the production and the activation of pro-fibrotic proteins (such as TGF-β, α-SMA, etc.) followed by the establishment of lung fibrosis

Purinergic signalling and immune cells

This review article provides a historical perspective on the role of purinergic signalling in the regulation of various subsets of immune cells from early discoveries to current understanding. It is now recognised that adenosine 5'-triphosphate (ATP) and other nucleotides are released from cells following stress or injury. They can act on virtually all subsets of immune cells through a spectrum of P2X ligand-gated ion channels and G protein-coupled P2Y receptors. Furthermore, ATP is rapidly degraded into adenosine by ectonucleotidases such as CD39 and CD73, and adenosine exerts additional regulatory effects through its own receptors. The resulting effect ranges from stimulation to tolerance depending on the amount and time courses of nucleotides released, and the balance between ATP and adenosine. This review identifies the various receptors involved in the different subsets of immune cells and their effects on the function of these cells

Should we train the trainers? Results of a randomized trial.

BACKGROUND: The development of efficient training methods in surgery is increasingly important. The effectiveness of training trainers is unclear. This study was designed to determine the effect on their trainees' performance of instructing trainers in a specific cognitive training method. STUDY DESIGN: Ten trainers from a university teaching hospital were randomized to train novices on a one-to-one basis in a simulated procedure using either a four-step cognitive method or their own unspecified method. Thirty trainees were randomly assigned to either a cognitive or standard trainer. After training, trainees were assessed on performing the procedure using a task-specific checklist, a global rating scale, and time taken to complete the procedure. RESULTS: Trainees who were trained using the specific cognitive method completed the procedure in a faster time (mean 331 seconds [SD 37 seconds] versus 426 seconds [SD 66 seconds]) and with higher global rating scores (mean 23.25 seconds [SD 3.7 seconds] versus 20.5 seconds [SD 4.5 seconds]) compared with those taught by a standard method. CONCLUSIONS: Instructing trainers in a cognitive training method results in a significant improvement in training outcomes

Factors influencing incident reporting in surgical care.

OBJECTIVES: To evaluate the process of incident reporting in a surgical setting. In particular: the influence of event outcome on reporting behaviour; staff perception of surgical complications as reportable events. DESIGN: Anonymous web-based questionnaire survey. SETTING: General Surgical Department in a UK teaching hospital. POPULATION: Of 203 eligible staff, 55 (76.4%) doctors and 82 (62.6%) nurses participated. MAIN OUTCOME MEASURES: Knowledge and use of local reporting system; propensity to report incidents which vary by outcome (harm, no harm, harm prevented); propensity to report surgical complications; practical and psychological barriers to reporting. RESULTS: Nurses were significantly more likely to know of the local reporting system and to have recently completed a report than doctors. The level of harm (F(1.8,246) = 254.2, p<0.001), incident type (F(1.9,258) = 64.4, p<0.001) and profession (F(1,135) = 20.7, p<0.001) all significantly affected the likelihood of reporting. Staff were most likely to report an incident when harm occurred. Doctors were significantly less likely to report surgical complications than other types of incident (15% vs 53%, z = 4.633, p<0.001). Fear was a significantly less important barrier to reporting than other reasons (z = -3.49, p<0.0002). CONCLUSION: An incident is more likely to be reported if harm results. Surgical complications are not generally perceived to be "reportable incidents," but they are addressed in Mortality and Morbidity meetings (MandM). Integrating MandM and incident reporting data will result in more comprehensive healthcare safety systems