Hydrologie et météorologie de méso-échelle dans HAPEX-Sahel : dispositif de mesures au sol et premiers résultats

Une étude de la recharge des nappes dans la zone expérimentale de HAPEX-Sahel, en rive droite du Niger, a été entreprise conjointement par l'Institut d'hydrologie de Wallingford et par le centre sahélien de l'ICRISAT. La zone d'étude couvre 600 km2 et est située sur le plateau de Say qui appartient aux formations du Continental Terminal. Les niveaux de l'aquifère ont été relevés mensuellement depuis mars 1991 sur 53 sites. La recharge sera estimée par modélisation de l'aquifère. Des analyses chimiques complètes, incluant les éléments traces, seront effectuées sur des échantillons prélevés en saison sèche et en saison humide. La recharge locale sur les sites de brousse tigrée, mil et jachère du Super-Site Sud de HAPEX-Sahel, sera aussi évaluée par le biais du calcul du bilan hydrique local. Enfin, le creusement d'un puits de 60 mètres de profondeur permettra d'analyser le profil des solutions de la zone non saturée et d'estimer les taux de recharge des dix dernières années. (Résumé d'auteur

Implementing clinical guidelines to prevent catheter-associated urinary tract infections and improve catheter care in nursing homes: Systematic review

BACKGROUND: Catheter-associated urinary tract infection is the most common health care-associated infection, is considered avoidable, and has cost implications for health services. Prevalence is high in nursing homes, but little research has been undertaken to establish whether implementing clinical guidelines can reduce infection rates in long-term care or improve quality of urinary catheter care. METHODS: Systematic search and critical appraisal of the literature. RESULTS: Three studies evaluated the impact of implementing a complete clinical guideline. Five additional studies evaluated the impact of implementing individual elements of a clinical guideline. CONCLUSIONS: Prevention of catheter-associated urinary tract infection in nursing homes has received little clinical or research attention. Studies concerned with whole guideline implementation emerged as methodologically poor using recognized criteria for critically appraising epidemiologic studies concerned with infection prevention. Research evaluating the impact of single elements of clinical guidelines is more robust, and their findings could be implemented to prevent urinary infections in nursing homes

False-positive troponin elevation due to an immunoglobulin-G-cardiac troponin T complex: a case report.

Background: Troponin is a crucial biomarker for the diagnosis of an acute coronary syndrome (ACS). It rises in response to myocardial injury from significant acute myocardial ischaemia caused by obstructive coronary artery disease ['classical' myocardial infarction (MI)]. However, raised levels have also been noted in conditions not recognized as classical ACS. This may include MI with non-obstructed coronary arteries such as takotsubo cardiomyopathy and other acute or chronic conditions such as pulmonary embolus or chronic kidney disease. This is commonly labelled as a 'falsely elevated' troponin although there is some myocardial strain to explain the rise, such as an increase in cardiac oxygen demand. True 'falsely elevated' troponin, characterized by a persistent elevation in the absence of cardiac injury does occur and thought to be secondary to an immunoglobulin-troponin complex (macrotroponin). Case summary: A 53-year-old gentleman with a background of diabetes, hypertension, hypercholesterolaemia, and hepatitis B was admitted with chest pain and persistently elevated cardiac troponin T (cTnT) levels. Investigations revealed unobstructed coronary arteries and a structurally normal, well-functioning heart. Subsequent biochemical analysis found the persistently elevated cTnT secondary to macrotroponin T. Discussion: Macrotroponin, an immunoglobulin-troponin bound complex should be considered as a differential diagnosis when the biochemistry is not reflective of the clinical picture. Early recognition requires effective collaboration with the biochemistry laboratory for accurate diagnosis

CRISPR-Cas antimicrobials: Challenges and future prospects

This is the final version. Available from PLoS via the DOI in this record.Antimicrobial resistance (AMR) poses a serious threat to modern medicine and may render common infections untreatable. The discovery of new antibiotics has come to a relative standstill during the last decade [1], and developing novel approaches to tackle the spread of AMR genes will require significant efforts in the coming years [2]. In 2014, several groups independently demonstrated how CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR–associated), a bacterial immune system now widely used for genome editing, can selectively remove AMR genes from bacterial populations. Here, we discuss the current state of the field of CRISPR-Cas antimicrobials, the challenges ahead, and how they may be overcome.Biotechnology & Biological Sciences Research Council (BBSRC)Medical Research CouncilNatural Environment Research CouncilWellcome TrustEuropean Research CouncilPeople Programme (Marie Curie Actions) of the European Union’s Horizon 202

Identifying Surrogates for Heart and Ipsilateral Lung Dose to Guide Field Placement and Treatment Modality Selection during Virtual Simulation of Breast Radiotherapy

AIMS: Virtual simulation (VSim) of tangential photon fields is a common method of field localisation for breast radiotherapy. Heart and ipsilateral lung dose is unknown until the dosimetric plan is produced. If heart and ipsilateral lung tolerance doses are exceeded, this can prolong the pre-treatment pathway, particularly if a change of technique is required. The aim of this study was to identify predictive surrogates for heart and ipsilateral lung dose during VSim to aid optimum field placement and treatment modality selection. MATERIALS AND METHODS: Computed tomography data from 50 patients referred for left breast/chest wall radiotherapy were retrospectively analysed (model-building cohort). The prescribed dose was 40.05 Gy in 15 fractions using a tangential photon technique. The heart and ipsilateral lung contours were duplicated, cropped to within the field borders and labelled heart-in-field (HIF) and ipsilateral lung-in-field (ILF). The percentage of HIF (%HIF) and ILF (%ILF) was calculated and correlated with mean heart dose (MHD) and volume of the ipsilateral lung receiving 18 Gy (V18Gy). Linear regression models were calculated. A validation cohort of 10 left- and 10 right-sided cases with an anterior supraclavicular fossa (SCF) field, and 10 left- and 10 right-sided cases including the internal mammary nodes using a wide tangential technique and anterior SCF field, tested the predictive model. Threshold values for %HIF and %ILF were calculated for clinically relevant MHD and ipsilateral lung V18Gy tolerance doses. RESULTS: For the model-building cohort, the median %HIF and MHD were 2.6 (0.4-16.7) and 2.3 (1.2-8) Gy. The median %ILF and ipsilateral lung V18Gy were 12.1 (2.8-33.6) and 12.6 (3.3-35) %. There was a statistically significant strong positive correlation of %HIF with MHD (r2 = 0.97, P < 0.0001) and of %ILF with ipsilateral lung V18Gy (r2 = 0.99, P < 0.0001). For the validation cohort, the median %HIF and MHD were 3.9 (0.6-8) and 2.5 (1.4-4.7) Gy. The median %ILF and ipsilateral lung V18Gy were 20.1 (12.4-32.0) and 20.9 (12.4-34.4) %. The validation cohort confirmed that %HIF and %ILF continue to be predictive surrogates for heart and ipsilateral lung dose during VSim of left- and right-sided cases when including the SCF ± internal mammary nodes with a three-field photon technique. DISCUSSION: The ability to VSim breast radiotherapy (±nodal targets) and accurately predict the heart and ipsilateral lung doses on the dosimetric plan will ensure that tolerance doses are not exceeded, and identify early in the pre-treatment pathway those cases where alternative techniques or modalities should be considered

Radiomics-Based Texture Analysis of Ga-68-DOTATATE Positron Emission Tomography and Computed Tomography Images as a Prognostic Biomarker in Adults With Neuroendocrine Cancers Treated With Lu-177-DOTATATE

Purpose: Neuroendocrine tumors (NET) are rare cancers with variable behavior. A better understanding of prognosis would aid individualized management. The aim of this hypothesis-generating pilot study was to investigate the prognostic potential of tumor heterogeneity and tracer avidity in NET using texture analysis (TA) of 68Ga-DOTATATE positron emission tomography (PET) and non-enhanced computed tomography (CT) performed at baseline in patients treated with 177Lu-DOTATATE. It aims to justify a larger-scale study to evaluate its clinical value. Methods: The pretherapy 68Ga-DOTATATE PET-CT scans of 44 patients with metastatic NET (carcinoid, pancreatic, thyroid, head and neck, catecholamine-secreting, and unknown primary NET) treated with 177Lu-DOTATATE were analyzed retrospectively using commercially available texture analysis research software. Image filtration extracted and enhanced objects of different sizes (fine, medium, coarse), then quantified heterogeneity by statistical and histogram-based parameters (mean intensity, standard deviation, entropy, mean of positive pixels, skewness, and kurtosis). Regions of interest were manually drawn around up to five of the most 68Ga-DOTATATE avid lesions for each patient. 68Gallium uptake on PET was quantified as SUVmax and SUVmean. Associations between imaging and clinical markers with progression-free (PFS) and overall survival (OS) were assessed using univariate Kaplan-Meier analysis. Independence of the significant univariate markers of survival was tested using multivariate Cox regression analysis. Results: Measures of heterogeneity (higher kurtosis, higher entropy, and lower skewness) on coarse-texture scale CT and unfiltered PET images predicted shorter PFS (CT coarse kurtosis: p=0.05, PET entropy: p=0.01, PET skewness: p=0.03) and shorter OS (CT coarse kurtosis: p=0.05, PET entropy: p=0.01, PET skewness p=0.02). Conventional PET parameters such as SUVmax and SUVmean showed trends towards predicting outcome but were not statistically significant. Multivariate analysis identified that CT-TA (coarse kurtosis: HR=2.57, 95% CI=1.22–5.38, p=0.013) independently predicted PFS, and PET-TA (unfiltered skewness: HR=9.05, 95% CI=1.19–68.91, p=0.033) independently predicted OS. Conclusion: These preliminary data generate a hypothesis that radiomic analysis of neuroendocrine cancer on 68Ga-DOTATATE PET-CT may be of prognostic value and a valuable addition to the assessment of patients