999 resultados para 157-954


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In an acidic protein medium Aspergillus fumigatus secretes an aspartic endoprotease (Pep) as well as tripeptidyl-peptidases, a prolyl-peptidase and carboxypeptidases. In addition, LC-MS/MS revealed a novel glutamic protease, AfuGprA, homologous to Aspergillus niger aspergillopepsin II. The importance of AfuGprA in protein digestion was evaluated by deletion of its encoding gene in A. fumigatus wild-type D141 and in a pepΔ mutant. Either A. fumigatus Pep or AfuGprA was shown to be necessary for fungal growth in protein medium at low pH. Exoproteolytic activity is therefore not sufficient for complete protein hydrolysis and fungal growth in a medium containing proteins as the sole nitrogen source. Pep and AfuGprA constitute a pair of endoproteases active at low pH, in analogy to A. fumigatus alkaline protease (Alp) and metalloprotease I (Mep), where at least one of these enzymes is necessary for fungal growth in protein medium at neutral pH. Heterologous expression of AfuGprA in Pichia pastoris showed that the enzyme is synthesized as a preproprotein and that the propeptide is removed through an autoproteolytic reaction at low pH to generate the mature protease. In contrast to A. niger aspergillopepsin II, AfuGprA is a single-chain protein and is structurally more similar to G1 proteases characterized in other non-Aspergillus fungi.

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Kirje 5.10.1973

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PPARs are nuclear hormone receptors which, like the retinoid, thyroid hormone, vitamin D, and steroid hormone receptors, are ligand-activated transcription factors mediating the hormonal control of gene expression. Two lines of evidence indicate that PPARs have an important function in fatty acid metabolism. First, PPARs are activated by hypolipidemic drugs and physiological concentrations of fatty acids, and second, PPARs control the peroxisomal beta-oxidation pathway of fatty acids through transcriptional induction of the gene encoding the acyl-CoA oxidase (ACO), which is the rate-limiting enzyme of the pathway. Furthermore, the PPAR signaling pathway appears to converge with the 9-cis retinoic acid receptor (RXR) signaling pathway in the regulation of the ACO gene because heterodimerization between PPAR and RXR is essential for in vitro binding to the PPRE and because the strongest stimulation of this gene is observed when both receptors are exposed simultaneously to their activators. Thus, it appears that PPARs are involved in the 9-cis retinoic acid signaling pathway and that they play a pivotal role in the hormonal control of lipid metabolism.

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Describe la técnicas que se necesitan para realizar un muestreo cuantitativo de peces y así obtener información básica que represente los principales aspectos biológicos de los recursos pelágicos a estudiar.

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Purpose: To evaluate whether parametric imaging with contrast material-enhanced ultrasonography (US) is superior to visual assessment for the differential diagnosis of focal liver lesions (FLLs). Materials and Methods: This study had institutional review board approval, and verbal patient informed consent was obtained. Between August 2005 and October 2008, 146 FLLs in 145 patients (63 women, 82 men; mean age, 62.5 years; age range, 22-89 years) were imaged with real-time low-mechanical-index contrast-enhanced US after a bolus injection of 2.4 mL of a second-generation contrast agent. Clips showing contrast agent uptake kinetics (including arterial, portal, and late phases) were recorded and subsequently analyzed off-line with dedicated image processing software. Analysis of the dynamic vascular patterns (DVPs) of lesions with respect to adjacent parenchyma allowed mapping DVP signatures on a single parametric image. Cine loops of contrast-enhanced US and results from parametric imaging of DVP were assessed separately by three independent off-site readers who classified each lesion as benign, malignant, or indeterminate. Sensitivity, specificity, accuracy, and positive and negative predictive values were calculated for both techniques. Interobserver agreement (κ statistics) was determined. Results: Sensitivities for visual interpretation of cine loops for the three readers were 85.0%, 77.9%, and 87.6%, which improved significantly to 96.5%, 97.3%, and 96.5% for parametric imaging, respectively (P < .05, McNemar test), while retaining high specificity (90.9% for all three readers). Accuracy scores of parametric imaging were higher than those of conventional contrast-enhanced US for all three readers (P < .001, McNemar test). Interobserver agreement increased with DVP parametric imaging compared with conventional contrast-enhanced US (change of κ from 0.54 to 0.99). Conclusion: Parametric imaging of DVP improves diagnostic performance of contrast-enhanced US in the differentiation between malignant and benign FLLs; it also provides excellent interobserver agreement.

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BACKGROUND: Trigeminal neuralgia (TN) related to multiple sclerosis (MS) is more difficult to manage pharmacologically and surgically. OBJECTIVE: This article aims to evaluate the safety and efficacy of Gamma Knife surgery (GKS) in this special group of patients. METHODS: Between July 1992 and November 2010, 43 cases with more than 1 year of follow-up were operated with GKS for TN related to MS and prospectively evaluated in the Timone University Hospital, Marseille, France. Radiosurgery using the Gamma Knife (model B or C or Perfexion) was performed. A single 4-mm isocenter was positioned at a median distance of 8 mm (range 5.7-14.7) anterior to the emergence of the nerve. A median maximum dose of 85 Gy (range 75-90) was delivered. RESULTS: The median follow-up period was 53.8 months (12-157.1). Thirty-nine patients (90.7%) were initially pain free. Their actuarial probability of remaining pain free without medication at 6 months, 1, 3, 5 and 10 years was 87.2, 71.8, 43.1, 38.3 and 20.5%, respectively, and remained stable till 12 years. The hypoesthesia actuarial rate at 6 months, 1 and 2 years was 11.5, 11.5 and 16%, and remained stable till 12 years. CONCLUSIONS: GKS proved safe and effective in this special group of patients.

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Distribución y variación de las principales propiedades del mar, los afloramientos, las masas de agua, circulación, el frente ecuatorial, el fenómeno del niño y fenómenos anormales en general, la producción de las aguas costeras en el Perú son puntos que desarrolla la investigación.

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El Cuadro de expertos realiza una investigación del Nivel del rendimiento máximo sostenido de la pesquería de anchoveta, los efectos de un aumento del esfuerzo de pesca así como las temporadas de veda. Finalmente recalcan la necesidad de continuar investigación del tema.

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Los resultados de 29 cruceros, realizados desde 1983 al 2000, muestran que la anchoveta ha presentado variaciones significativas en su biomasa y distribución, debido a los eventos El Niño 1982-83, 1987, 1992 y 1997-98, que la hicieron replegarse a la costa, migrar hacia el sur y profundizarse hasta lugares inusuales, disminuyendo los valores de las categorías de abundancia. Los mayores estimados de biomasa de anchoveta, se obtuvieron en los cruceros de evaluación hidroacústica de recursos pelágicos 9401-03 (8.700.590 t) y 0001-02 (9.439.027 t). La más alta biomasa estacional promedio por grados de latitud se determinó en primavera en los 8°5 (727.819 t), seguida del verano en los 11°s (701.724 t). Las altas biomasas promedio se encontraron entre los 7°S y 9° S. Los altos desembarques anuales promedio se registraron en verano (1.577.855 1). Los mayores desembarques se obtuvieron en 1994 (9.896.303 t) y en 1996 (7.136.856 t). Según el análisis de los parametros de biomasa y desembarques anuales entre los años de 1983 al 2000, se observa que existe una correlación significativa (r = 0,71) presentando un aceptable ajuste del modelo en R'•0,5 1.