Delayed otogenic hydrocephalus after acute otitis media in pediatric patients: the changing presentation of a serious otologic complication.

CONCLUSIONS: The clinical presentation of otogenic dural sinus thrombosis (DST) as a complication of acute otitis media (AOM) can be masked by antibiotic treatment. Morning episodes of vomiting and/or headache, visual impairment and a history of AOM seem to be indicative of otogenic hydrocephalus. We therefore advocate that the MRI scans of patients with similar symptoms should be carefully studied to facilitate the early diagnosis of a potentially life-threatening complication. OBJECTIVE: To describe the frequency, pathognomonic signs, clinical course and outcome of otogenic hydrocephalus and DST as complications of AOM in pediatric patients. MATERIAL AND METHODS: We undertook a retrospective chart review of all pediatric patients (age 1-14 years) treated for otitis media and its complications at an academic medical center between 1999 and 2003. The main outcome measures were otologic and ophthalmologic findings and CT and MRI scans at the beginning of treatment and 3 months later. RESULTS: We report on five cases with otogenic DST following AOM. All but one of them presented initially with diplopia caused by otogenic hydrocephalus. In four cases the otologic complaints had already disappeared by the time of MRI confirmation of the diagnosis. Only one child was referred with severe otologic symptoms. Management included systemic antibiotics, short-term heparin anticoagulation and surgical decompression. In our cases, even after intensive i.v. antibiotic treatment, only surgery led to a significant improvement in the clinical condition.

Hybrid Multiscale Finite Volume method for two-phase flow in porous media

We present a novel hybrid (or multiphysics) algorithm, which couples pore-scale and Darcy descriptions of two-phase flow in porous media. The flow at the pore-scale is described by the Navier?Stokes equations, and the Volume of Fluid (VOF) method is used to model the evolution of the fluid?fluid interface. An extension of the Multiscale Finite Volume (MsFV) method is employed to construct the Darcy-scale problem. First, a set of local interpolators for pressure and velocity is constructed by solving the Navier?Stokes equations; then, a coarse mass-conservation problem is constructed by averaging the pore-scale velocity over the cells of a coarse grid, which act as control volumes; finally, a conservative pore-scale velocity field is reconstructed and used to advect the fluid?fluid interface. The method relies on the localization assumptions used to compute the interpolators (which are quite straightforward extensions of the standard MsFV) and on the postulate that the coarse-scale fluxes are proportional to the coarse-pressure differences. By numerical simulations of two-phase problems, we demonstrate that these assumptions provide hybrid solutions that are in good agreement with reference pore-scale solutions and are able to model the transition from stable to unstable flow regimes. Our hybrid method can naturally take advantage of several adaptive strategies and allows considering pore-scale fluxes only in some regions, while Darcy fluxes are used in the rest of the domain. Moreover, since the method relies on the assumption that the relationship between coarse-scale fluxes and pressure differences is local, it can be used as a numerical tool to investigate the limits of validity of Darcy's law and to understand the link between pore-scale quantities and their corresponding Darcy-scale variables.

Error estimate and control in the MSFV method for multiphase flow in porous media

n this paper the iterative MSFV method is extended to include the sequential implicit simulation of time dependent problems involving the solution of a system of pressure-saturation equations. To control numerical errors in simulation results, an error estimate, based on the residual of the MSFV approximate pressure field, is introduced. In the initial time steps in simulation iterations are employed until a specified accuracy in pressure is achieved. This initial solution is then used to improve the localization assumption at later time steps. Additional iterations in pressure solution are employed only when the pressure residual becomes larger than a specified threshold value. Efficiency of the strategy and the error control criteria are numerically investigated. This paper also shows that it is possible to derive an a-priori estimate and control based on the allowed pressure-equation residual to guarantee the desired accuracy in saturation calculation.

Media exposure and internal migration-evidence from Indonesia

This paper investigates the impact of television on internal migration in Indonesia. We exploit the differential introduction of private television throughout the country and the variation in signal reception due to topography to estimate the causal effect of media exposure. Our estimates reveal important long and short run effects. An increase of one standard deviation in the number of private TV channels received in the area of residence reduces future inter-provincial migration by 1.7-2.7 percentage points, and all migration (inter and intra-provincial) by 4-7.4 percentage points. Short run effects are slightly smaller, but still sizeable and statistically significant. We also show that respondents less exposed to private TV are more likely to consider themselves among the poorest groups of the society. As we discuss in a stylized model of migration choice under imperfect information, these findings are consistent with Indonesia citizens over-estimating the net gains from internal migration.

How Low Can We Go in Contrast-Enhanced CT Imaging of the Chest?: A Dose-Finding Cadaver Study Using the Model-based Iterative Image Reconstruction Approach.

RATIONALE AND OBJECTIVES: Dose reduction may compromise patients because of a decrease of image quality. Therefore, the amount of dose savings in new dose-reduction techniques needs to be thoroughly assessed. To avoid repeated studies in one patient, chest computed tomography (CT) scans with different dose levels were performed in corpses comparing model-based iterative reconstruction (MBIR) as a tool to enhance image quality with current standard full-dose imaging. MATERIALS AND METHODS: Twenty-five human cadavers were scanned (CT HD750) after contrast medium injection at different, decreasing dose levels D0-D5 and respectively reconstructed with MBIR. The data at full-dose level, D0, have been additionally reconstructed with standard adaptive statistical iterative reconstruction (ASIR), which represented the full-dose baseline reference (FDBR). Two radiologists independently compared image quality (IQ) in 3-mm multiplanar reformations for soft-tissue evaluation of D0-D5 to FDBR (-2, diagnostically inferior; -1, inferior; 0, equal; +1, superior; and +2, diagnostically superior). For statistical analysis, the intraclass correlation coefficient (ICC) and the Wilcoxon test were used. RESULTS: Mean CT dose index values (mGy) were as follows: D0/FDBR = 10.1 ± 1.7, D1 = 6.2 ± 2.8, D2 = 5.7 ± 2.7, D3 = 3.5 ± 1.9, D4 = 1.8 ± 1.0, and D5 = 0.9 ± 0.5. Mean IQ ratings were as follows: D0 = +1.8 ± 0.2, D1 = +1.5 ± 0.3, D2 = +1.1 ± 0.3, D3 = +0.7 ± 0.5, D4 = +0.1 ± 0.5, and D5 = -1.2 ± 0.5. All values demonstrated a significant difference to baseline (P < .05), except mean IQ for D4 (P = .61). ICC was 0.91. CONCLUSIONS: Compared to ASIR, MBIR allowed for a significant dose reduction of 82% without impairment of IQ. This resulted in a calculated mean effective dose below 1 mSv.

Retinal fluorescein contrast arrival time of young patients with the hepatosplenic form of the Schistosomiasis mansoni

Schistosoma mansoni is responsible for lesions that can alter the hemodinamic of the portal venous circulation, lung arterial and venous sistemic systems. Therefore, hemodinamic changes in the ocular circulation of mansonic schistosomotic patients with portal hypertension and hepatofugal venous blood flow is also probable. The purpose of this study was to determine the fluorescein contrast arrival time at the retina of young patients with the hepatosplenic form of schistosomiasis, clinically and surgically treated. The control group included 36 non schistosomotic patients, mean age of 17.3 years, and the case group was represented by 25 schistosomotic patients, mean age of 18.2 years, who were cared for at The University Hospital (Federal University of Pernambuco, Brazil), from 1990 to 2001. They underwent digital angiofluoresceinography and were evaluated for the contrast arrival time at the early retinal venous phase of the exam. Both groups were ophthalmologically examined at the same hospital (Altino Ventura Foundation, Recife, Brazil), using the same technique. There was retardation of the retinal contrast arrival time equal or more than 70 sec in the eyes of three schistosomotic patients (12%) and in none of the control group, however, the mean contrast arrival time between the two groups were not statistically different. These findings lend support to the hypothesis that there could be a delay of the eye venous blood flow drainage.

Phase Contrast X-Ray Tomographic Microscopy for Biological and Materials Science Applications

The application of two approaches for high-throughput, high-resolution X-ray phase contrast tomographic imaging being used at the tomographic microscopy and coherent radiology experiments (TOMCAT) beamline of the SLS is discussed and illustrated. Differential phase contrast (DPC) imaging, using a grating interferometer and a phase-stepping technique, is integrated into the beamline environment at TOMCAT in terms of the fast acquisition and reconstruction of data and the availability to scan samples within an aqueous environment. A second phase contrast method is a modified transfer of intensity approach that can yield the 3D distribution of the decrement of the refractive index of a weakly absorbing object from a single tomographic dataset. The two methods are complementary to one another: the DPC method is characterised by a higher sensitivity and by moderate resolution with larger samples; the modified transfer of intensity approach is particularly suited for small specimens when high resolution (around 1 mu m) is required. Both are being applied to investigations in the biological and materials science fields.

Media guidelines for reporting suicide and self-harm

These guidelines are for those in the media who have involvement with the reporting or portrayal of suicide and represent an important source of information to help ensure that the quality of reporting and portrayal on this important and sensitive topic is of a high standard.

Escherichia coli variants in periprosthetic joint infection: diagnostic challenges with sessile bacteria and sonication.

The diagnostic yield of prosthetic joint-associated infection is hampered by the phenotypic change of bacteria into a sessile and resistant form, also called biofilm. With sonication, adherent bacteria can be dislodged from the prosthesis. Species identification may be difficult because of their variations in phenotypic appearance and biochemical reaction. We have studied the phenotypic, genotypic, and biochemical properties of Escherichia coli variants isolated from a periprosthetic joint infection. The strains were collected from synovial fluid, periprosthetic tissue, and fluid from the explanted and sonicated prosthesis. Isolates from synovial fluid revealed a normal phenotype, whereas a few variants from periprosthetic tissue and all isolates from sonication fluid showed different morphological features (including small-colony variants). All isolates from sonication fluid were beta-galactosidase negative and nonmotile; most were indole negative. Because of further variations in biochemical properties, species identification was false or not possible in 50% of the isolates included in this study. In contrast to normal phenotypes, variants were resistant to aminoglycosides. Typing of the isolates using pulsed-field gel electrophoresis yielded nonidentical banding patterns, but all strains were assigned to the same clonal origin when compared with 207 unrelated E. coli isolates. The bacteria were repeatedly passaged on culture media and reanalyzed. Thereafter, most variants reverted to normal phenotype and regained their motility and certain biochemical properties. In addition, some variants displayed aminoglycoside susceptibility after reversion. Sonication of an explanted prosthesis allows insight into the lifestyle of bacteria in biofilms. Since sonication fluid also reveals dislodged sessile forms, species identification of such variants may be misleading.

Leishmania (Viannia) braziliensis growth in vitro culture relies more on folic acid availability than Leihsmania (Leishmania) amazonensis

We compared the in vitro growth of promastigotes from two Leishmania species in TC-100 and Schneider media. Leishmania (Leishmania) amazonensis replication rates were similar in both tissue culture media and reached maximum rates by 48 h. In contrast Leishmania (Viannia) braziliensis growth was significantly greater in TC-100 but maximum rates were achieved by 96 h. Folic acid appears to be the limiting factor and supplementation of Schneider media with this nutrient improved L. (V.) braziliensis replication rates and decreased the time of maximum replication to 48 h.

Calculation of correction factors for ionization chamber measurements with small fields in low-density media.

The quantity of interest for high-energy photon beam therapy recommended by most dosimetric protocols is the absorbed dose to water. Thus, ionization chambers are calibrated in absorbed dose to water, which is the same quantity as what is calculated by most treatment planning systems (TPS). However, when measurements are performed in a low-density medium, the presence of the ionization chamber generates a perturbation at the level of the secondary particle range. Therefore, the measured quantity is close to the absorbed dose to a volume of water equivalent to the chamber volume. This quantity is not equivalent to the dose calculated by a TPS, which is the absorbed dose to an infinitesimally small volume of water. This phenomenon can lead to an overestimation of the absorbed dose measured with an ionization chamber of up to 40% in extreme cases. In this paper, we propose a method to calculate correction factors based on the Monte Carlo simulations. These correction factors are obtained by the ratio of the absorbed dose to water in a low-density medium □D(w,Q,V1)(low) averaged over a scoring volume V₁ for a geometry where V₁ is filled with the low-density medium and the absorbed dose to water □D(w,QV2)(low) averaged over a volume V₂ for a geometry where V₂ is filled with water. In the Monte Carlo simulations, □D(w,QV2)(low) is obtained by replacing the volume of the ionization chamber by an equivalent volume of water, according to the definition of the absorbed dose to water. The method is validated in two different configurations which allowed us to study the behavior of this correction factor as a function of depth in phantom, photon beam energy, phantom density and field size.