Práctica de la ecografía en el ámbito de las emergencias. La tozuda realidad cuando no está cerca el radiólogo / Ultrasound practice in emergency medicine. Stubborn reality when the radiologist is missing

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Photo-chemical study and optical properties of microtips self- written on vertical laser diodes using NIR photo-polymerization.

Near infra-red (NIR) self-guided photo-polymerization is investigated in the context of micro-optics photo-fabrication on VCSELs (Vertical-Cavity Surface Emitting Lasers). We present the optimized process we have developed to allow for a collective fabrication on III-V devices wafers under real-time optical monitoring. The influence of photo-chemical parameters on final micro-elements dimensions is studied for two types of single mode 760 nm VCSELs. The difference of the resulting tip shape between the two lasers is due to the strong differences of their emissions, as they are nicely reproduced by the computed near-field profiles. The tip shapes are also compared to those produced by the light emitted by an optical fiber and differences with VCSEL tips are discussed. Also the VCSEL characteristics with fabricated tips are discussed and found in good agreement with optical modeling.

Fabrication and characterization of microlens arrays using a cantilever-based spotter.

We present a quantitative study on the fabrication of microlenses using a low-cost polymer dispending technique. Our method is based on the use of a silicon micro-cantilever robotized spotter system. We first give a detailed description of the technique. In a second part, the fabricated microlenses are fully characterized by means of SEM (Scanning Electron Microscope), AFM (Atomic Force Microscopy) non contact optical profilometry and Mach-Zehnder interferometry. Diameters in the range [25-130mum] are obtained with an average surface roughness of 2.02nm. Curvature radii, focal lengths as well as aberrations are also measured for the first time: the fabricated microlenses present focal lengths in the range [55-181mum] and exhibit high optical quality only limited by diffraction behaviour with RMS aberration lower than lambda/14.

Factors predictive of response to interferon therapy in children with chronic hepatitis B.

BACKGROUND/AIMS: The efficacy of interferon therapy in Caucasian children with chronic hepatitis B is similar to that in adults. However, little information is available about factors predicting response to this therapy in children. We have performed a univariate analysis to assess the strength of association between basal variables and response, and a multivariate analysis to determine the combination of basal variables which give the best prediction of response in terms of sensitivity and specificity. METHODS: The basal parameters were studied in 50 children included in three different trials of interferon alpha therapy (360-700 MU/square meter of body surface, 2 or 3 times weekly for 12 to 24 weeks). RESULTS: Of these, 18 (36%) were responders. In the univariate analysis, a higher histological activity (p < 0.05), a lower percentage of HBcAg-stained hepatocytes (p < 0.001), aspartate amino transferase and alanine aminotransferase levels (p < 0.05) and alanine aminotransferase peak prior to serum HBV-DNA clearance (p < 0.05), were associated to the response. In the multivariate analysis, the combinations of the percentage of HBcAg stained cells with alanine aminotransferase levels and with the histological activity index were the best variables for predicting response (sensitivity: 100% and specificity: 89% and 86%, respectively). CONCLUSIONS: Factors predictive of response in children with chronic hepatitis B are similar to those found in adults, and may help in identifying those children with a better chance of responding.

Serological and histological follow up of chronic hepatitis B infection.

In order to study the clinical, serological, and morphological evolution of chronic hepatitis B virus infection in childhood, a prospective study has been carried out. A total of 90 children with a chronic infection were followed up for a mean (SD) of 3 (1.8) years. At the beginning of the study, 61 children were asymptomatic and 77 were household contacts of chronic carriers. Serologically 77 were hepatitis B e antigen (HBeAg) positive and 71 of them were positive to hepatitis B virus DNA. The mean alanine aminotransferase activities were higher among HBeAg positive patients than in antihepatitis B e (anti-HBe) positive ones. The most severe histological damage was also found among HBeAg positive patients. The annual seroconversion rate was 14%. A significant increase in the alanine aminotransferase activity was observed 13 (5.6) months before appearance of anti-HBe in the 85% of cases. Among anti-HBe positive patients, the alanine aminotransferase activities were normal in all except three (19%), two of whom had intrahepatic delta antigen. An increase in the histological activity was observed among patients who maintained HBeAg presence while an amelioration of liver damage was observed in anti-HBe carriers.

Regulation of protein phosphatase activity by the deinhibitor protein.

In liver and muscle the major active phosphorylase and synthase phosphatase activity is associated with the glycogen particle. When we examined the effect of the inhibitor-1 and modulator protein on the enzyme present in crude glycogen fractions from dog liver, the phosphorylase phosphatase was not or only slightly affected. Since the enzyme isolated from the glycogen complex by DEAE-cellulose chromatography could be inhibited by inhibitor-1 as well as the modulator protein, it was assumed that an unknown mechanism or factor present in the glycogen fraction was responsible for this reduced sensitivity of the protein phosphatase. This led to the discovery (7) of the deinhibitor protein which has now been extensively purified from dog liver. The deinhibitor protein was shown to be thermostable, ethanol- and trichloroacetic acid-resistant, but non-dialyzable and it was destroyed by pronase or trypsin. The apparent molecular weight was estimated at about 17,500 in gel filtration, 8,300 in sodium dodecyl sulfate polyacrylamide gel electrophoresis and 5,500 in sucrose density gradient centrifugation, behavior which is consistent with the assumption that the deinhibitor protein may have little ordered structure. Glycogen synthesis requires both phosphorylase and glycogen synthase as dephosphorylated enzymes. The interaction of the deinhibitor protein with the protein phosphatase brings about several effects which, when considered together, could all facilitate the dephosphorylation of glycogen synthase and phosphorylase. The protein phosphatase present in a resuspended glycogen pellet dephosphorylates inhibitor-1 in the absence of Mn2+. This ability of the phosphatase, which is lost during purification of the enzyme, can be restored upon addition of the deinhibitor protein. Owing to the association of the deinhibitor protein with the active phosphatase the enzyme becomes insensitive to inhibition by inhibitor-1 and the modulator protein, and more resistant to the conversion into the FA-ATP,Mg-dependent form, brought about by the modulator protein. During the activation of the ATP,Mg-dependent phosphatase under conditions where kinase FA is rate limiting, the deinhibitor protein increases the level without affecting the rate of activation.