892 research outputs found

    Nuclear Factors Bind to a Conserved DNA Element That Modulates Transcription of Anopheles gambiae Trypsin Genes

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    The Anopheles gambiae trypsin family consists of seven genes that are transcribed in the gut of female mosquitoes in a temporal coordinated and mutually exclusive manner, suggesting the involvement of a complex transcription regulatory mechanism. We identified a highly conserved 12-nucleotide motif present in all A. gambiae and Anopheles stephensi trypsin promoters. We investigated the role of this putative trypsin regulatory element (PTRE) in controlling the transcription of the trypsin genes. Gel shift experiments demonstrated that nuclear proteins of A. gambiae cell lines formed two distinct complexes with probes encompassing the PTRE sequence. Mapping of the binding sites revealed that one of the complex has the specificity of a GATA transcription factor. Promoter constructs containing mutations in the PTRE sequence that selectively abolished the binding of either one or both complexes exerted opposite effects on the transcriptional activity of trypsin promoters in A. gambiae and Aedes aegypti cell lines. In addition, the expression of a novel GATA gene was highly enriched in A. gambiae guts. Taken together our data prove that factors binding to the PTRE region are key regulatory elements possibly involved in the blood meal-induced repression and activation of transcription in early and late trypsin genes

    Reduction in the use of diagnostic tests in infants with risk factors for early-onset neonatal sepsis does not delay antibiotic treatment.

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    Despite a low positive predictive value, diagnostic tests such as complete blood count (CBC) and C-reactive protein (CRP) are commonly used to evaluate whether infants with risk factors for early-onset neonatal sepsis (EOS) should be treated with antibiotics. We investigated the impact of implementing a protocol aiming at reducing the number of diagnostic tests in infants with risk factors for EOS in order to compare the diagnostic performance of repeated clinical examination with CBC and CRP measurement. The primary outcome was the time between birth and the first dose of antibiotics in infants treated for suspected EOS. Among the 11,503 infants born at ≥35 weeks during the study period, 222 were treated with antibiotics for suspected EOS. The proportion of infants receiving antibiotics for suspected EOS was 2.1% and 1.7% before and after the change of protocol (p = 0.09). Reduction of diagnostic tests was associated with earlier antibiotic treatment in infants treated for suspected EOS (hazard ratio 1.58; 95% confidence interval [CI] 1.20-2.07; p <0.001), and in infants with neonatal infection (hazard ratio 2.20; 95% CI 1.19-4.06; p = 0.01). There was no difference in the duration of hospital stay nor in the proportion of infants requiring respiratory or cardiovascular support before and after the change of protocol. Reduction of diagnostic tests such as CBC and CRP does not delay initiation of antibiotic treatment in infants with suspected EOS. The importance of clinical examination in infants with risk factors for EOS should be emphasised

    Spatial genetic structure and genetic diversity of a natural population of Ramorinoa girolae in San Juan province (Argentina) : an exploratory analysis

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    Ramorinoa girolae Speg. (chica) es un árbol endémico nativo de la flora xerófta argentina. A esta especie se la considera un recurso forestal muy apreciado debido a sus frutos (que constituyen una parte importante de la dieta de los pobladores locales) y su madera (una de las más duras). Además, la chica fue clasifcada como una especie vulnerable porque es una especie monotípica de abundancia baja, con un endemismo muy restricto (limitado a las provincias de San Juan, San Luis y La Rioja) y con poca resistencia al fuego. Dado que existe escasa información sobre el estatus de la diversidad genética de la especie, realizamos un análisis exploratorio para caracterizar la diversidad genética de una población natural ubicada en la proximidad del Parque Provincial Ischigualasto (San Juan, Argentina) por medio de marcadores moleculares AFLP en 19 individuos. Los datos genéticos se correlacionaron con datos morfométricos, ecológicos y geográfcos. Nuestros resultados sugieren que esta población posee una diversidad genética elevada (Pj=82.3%). Además, estos valores se correlacionaron con matrices geográfcas, lo que reveló que la población exhibió una particular estructura genética espacial (SGS, Prueba de Mantel r=0.45; P<0.001). Por otra parte, los valores de similitud genética entre los diferentes individuos analizados revelaron la ausencia de clones, lo que sugiere una contribución signifcativa de la variabilidad genética producto de la reproducción sexual en la población estudiada.Ramorinoa girolae Speg. (chica) is an endemic tree species which belongs to the Argentinian xerophyte flora. This species constitutes an appreciated forest resource for local people due to its fruits (a substantial basis of the diet of local communities) and its timber (one of the hardest woods). Moreover, chica was pointed as a vulnerable species because it is a monotypic species with low abundance and a very restricted endemism (San Juan, San Luis and La Rioja provinces). There is limited information concerning the status of genetic diversity of the species. For this, we performed an exploratory analysis to characterize the genetic diversity of a natural population located near Ischigualasto Provincial Park (San Juan, Argentina) using AFLP molecular markers in 19 individuals. The genetic data were correlated with morphometric, ecological and geographical data. Our results suggest that this population exhibited a high genetic diversity (Pj=82.3%). These values also were correlated with geographical matrices, revealing that this population exhibited a particular spatial genetic structure (SGS; Mantel Test r=0.45, P<0.001) and spatial autocorrelation. In addition, values of genetic similarity among the different analyzed individuals revealed the absence of clones, suggesting a significant contribution of genetic variability due to sexual reproduction in the studied population

    A Morse-theoretical analysis of gravitational lensing by a Kerr-Newman black hole

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    Consider, in the domain of outer communication of a Kerr-Newman black hole, a point (observation event) and a timelike curve (worldline of light source). Assume that the worldline of the source (i) has no past end-point, (ii) does not intersect the caustic of the past light-cone of the observation event, and (iii) goes neither to the horizon nor to infinity in the past. We prove that then for infinitely many positive integers k there is a past-pointing lightlike geodesic of (Morse) index k from the observation event to the worldline of the source, hence an observer at the observation event sees infinitely many images of the source. Moreover, we demonstrate that all lightlike geodesics from an event to a timelike curve in the domain of outer communication are confined to a certain spherical shell. Our characterization of this spherical shell shows that in the Kerr-Newman spacetime the occurrence of infinitely many images is intimately related to the occurrence of centrifugal-plus-Coriolis force reversal.Comment: 14 pages, 2 figures; REVTEX; submitted to J. Math. Phy

    Biosensors to Monitor Cell Activity in 3D Hydrogel-Based Tissue Models

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    Three-dimensional (3D) culture models have gained relevant interest in tissue engineering and drug discovery owing to their suitability to reproduce in vitro some key aspects of human tissues and to provide predictive information for in vivo tests. In this context, the use of hydrogels as artificial extracellular matrices is of paramount relevance, since they allow closer recapitulation of (patho)physiological features of human tissues. However, most of the analyses aimed at characterizing these models are based on time-consuming and endpoint assays, which can provide only static and limited data on cellular behavior. On the other hand, biosensing systems could be adopted to measure on-line cellular activity, as currently performed in bi-dimensional, i.e., monolayer, cell culture systems; however, their translation and integration within 3D hydrogel-based systems is not straight forward, due to the geometry and materials properties of these advanced cell culturing approaches. Therefore, researchers have adopted different strategies, through the development of biochemical, electrochemical and optical sensors, but challenges still remain in employing these devices. In this review, after examining recent advances in adapting existing biosensors from traditional cell monolayers to polymeric 3D cells cultures, we will focus on novel designs and outcomes of a range of biosensors specifically developed to provide real-time analysis of hydrogel-based cultures

    Non-Invasive Estimation of Right Atrial Pressure Using a Semi-Automated Echocardiographic Tool for Inferior Vena Cava Edge-Tracking

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    The non-invasive estimation of right atrial pressure (RAP) would be a key advancement in several clinical scenarios, in which the knowledge of central venous filling pressure is vital for patients’ management. The echocardiographic estimation of RAP proposed by Guidelines, based on inferior vena cava (IVC) size and respirophasic collapsibility, is exposed to operator and patient dependent variability. We propose novel methods, based on semi-automated edge-tracking of IVC size and cardiac collapsibility (cardiac caval index—CCI), tested in a monocentric retrospective cohort of patients undergoing echocardiography and right heart catheterization (RHC) within 24 h in condition of clinical and therapeutic stability (170 patients, age 64 ± 14, male 45%, with pulmonary arterial hypertension, heart failure, valvular heart disease, dyspnea, or other pathologies). IVC size and CCI were integrated with other standard echocardiographic features, selected by backward feature selection and included in a linear model (LM) and a support vector machine (SVM), which were cross-validated. Three RAP classes (low 10 mmHg) were generated and RHC values used as comparator. LM and SVM showed a higher accuracy than Guidelines (63%, 71%, and 61% for LM, SVM, and Guidelines, respectively), promoting the integration of IVC and echocardiographic features for an improved non-invasive estimation of RAP

    Applicability of a forecasting chain in a different morphological environment in Italy

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    International audienceThe operational meteo-hydrological forecasting chain of the Liguria Region (NW Italy) is applied to a different morphoclimatic environment, such as the Emilia Romagna Region (N Italy). Modification to the chain, both in models and in procedures, are introduced to overcome problems related to medium dimension catchments (A?1000km2), characterized by complex altimetry profiles and antropical interventions along the river. The main feature of the original operational procedure, that is the probabilistic approach, is maintained. Hydraulic hazard reduction through artificial reservoirs management is exploited with reference to a specific event occurred on the Reno basin (Emilia Romagna Region)

    Universal statistics of wave functions in chaotic and disordered systems

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    We study a new statistics of wave functions in several chaotic and disordered systems: the random matrix model, band random matrix model, the Lipkin model, chaotic quantum billiard and the 1D tight-binding model. Both numerical and analytical results show that the distribution function of a generalized Riccati variable, defined as the ratio of components of eigenfunctions on basis states coupled by perturbation, is universal, and has the form of Lorentzian distribution.Comment: 6 Europhys pages, 2 Ps figures, new version to appear in Europhys. Let

    Abnormal hyperventilation in patients with hepatic cirrhosis: Role of enhanced chemosensitivity to carbon dioxide

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    BACKGROUND: Patients with hepatic cirrhosis frequently show idiopathic hyperventilation at rest, despite no concomitant cardiopulmonary disease. The aim of the study was to determine whether altered chemosensitivity either to hypoxia or hypercapnia could underlie inappropriate hyperventilation in cirrhotic patients. METHODS: We consecutively recruited 30 biopsy proven cirrhotic patients equally distributed in the three Child's classes A, B and C (age 54±8years, mean±SD). All patients underwent evaluation of chemosensitivity to hypoxia and to hypercapnia and blood sampling for brain natriuretic peptide, norepinephrine and progesterone, besides full clinical characterization. We also recruited 10 age- and gender-matched healthy controls (age 55±7years). RESULTS: Overall, 18 patients (60%) showed an increased chemosensitivity to carbon dioxide (CO(2)), while 8 patients (27%) showed enhanced chemosensitivity to hypoxia. Child's class C patients had lower arterial partial pressure of CO(2) (PaCO(2)), higher rest ventilation, increased chemosensitivity to hypercapnia, plasma level of norepinephrine and serum progesterone levels when compared to class A patients and controls (all p<0.05). Rest ventilation was positively related to pH (R=0.41, p=0.023), chemosensitivity to hypercapnia (R=0.54, p=0.002), and progesterone (R=0.53, p=0.016) and negatively to PaCO(2) (R=0.61, p<0.001), but not to hemoglobin level and chemosensitivity to hypoxia. Chemosensitivity to hypercapnia was positively related to PaCO(2) (R=0.74, p<0.001), serum progesterone (R=0.50, p=0.016), and to plasma norepinephrine (R=0.57, p=0.004). CONCLUSIONS: Enhanced chemosensitivity to hypercapnia was found in more decompensated cirrhotic patients and was associated with sympathetic overactivity and elevated serum progesterone, likely representing a key mechanism underlying the "unexplained" hyperventilation observed in such patients
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