443 research outputs found
Drug Hypersensitivity Syndrome toCarbamazepine and Human Herpes Virus 6 Infection: Case Reportand Literature Review
Abstract.: We describe a patient with a drug-induced hypersensitivity syndrome to carbamazepine and a concomitant active infection with human herpes virus 6 (HHV-6). The potential role of HHV-6 regarding the drug-induced hypersensitivity syndrome is discussed and the main clinical features of this potentially fatal adverse drug reaction are highlighte
Effect of thoracic venting on arterial pressure, and flow during external cardiopulmonary resuscitation in animals
To test the hypothesis that fluctuations in global intrathoracic pressure are the dominant cause of blood flow during external cardiopulmonary resuscitation (CPR) the authors studied the effects of open pneumothorax on experimental CPR in 7 domestic pigs and 12 mongrel dogs. Similar studies were conducted independently at three laboratories and are reported jointly. All studies were conducted during electrically induced ventricular fibrillation and with standard CPR technique, including ventral-dorsal chest compression at 60/min, 0.5 sec compression duration, 1:5ventilation:compression ratio. During alternate periods of CPR, intrathoracic pressure was vented through bilateral chest tubes, placed to create open pneumothorax and partial collapse of the lungs. During this maneuver, global intrathoracic pressure fluctuations were greatly attenuated, but direct but direct cardiac compression and adequate ventilation continued. In the three laboratories, systolic/diastolic arterial pressures during CPR with thoracic venting (± SE) averaged 68 ± 4.2/28 ± 3.3, 60 ± 10/18 ± 4.5, and 66 ± 6.3/23 ± 1.5 mm Hg. These values are compared to 68 ± 4.4/27 ± 3.0, 67 ± 12/17 ± 6.1, and 56± 6.2/22 ± 1.9 mm Hg with the thorax intact. Carotid artery mean flow, measured with an in-line flowmeter, was 13.0 ± 2.2 ml/min vented vs. 13.4 ± 2.6 intact in 7 pigs; 11.4 ± 3.8 ml/min vented vs. 11.2 ± 3.7 intact in 5 dogs. Cardiac output, determined by indicator dilution, was 25 ± 4.3 ml/min/kg vented vs. 20 ± 4.3 intact in 7 dogs. Thoracic venting did not decrease blood pressures and flows during CPR, as would be predicted from the hypothesis that generalized intrathoracic pressure fluctuations are the dominant hemodynamic mechanism. The results are consistent with the classical notion that CPR works by compression of the heart between the sternum and the spine. This mechanism should not be discounted in future attempts to improve CPR
SMOS calibration and validation activities with airborne interferometric radiometer HUT-2D during spring 2010
In this paper we present calibration and validation activities of European Space Agency’s SMOS mission, which utilize airborne interferomentric L-band radiometer system HUT-2D of the Aalto University. During spring 2010 the instrument was used to measure three SMOS validation target areas, one in Denmark and two in Germany. We present these areas shortly, and describe the airborne activities. We show some exemplary measurements of the radiometer system and demonstrate the studies using the data
Crater formation by fast ions: comparison of experiment with Molecular Dynamics simulations
An incident fast ion in the electronic stopping regime produces a track of
excitations which can lead to particle ejection and cratering. Molecular
Dynamics simulations of the evolution of the deposited energy were used to
study the resulting crater morphology as a function of the excitation density
in a cylindrical track for large angle of incidence with respect to the surface
normal. Surprisingly, the overall behavior is shown to be similar to that seen
in the experimental data for crater formation in polymers. However, the
simulations give greater insight into the cratering process. The threshold for
crater formation occurs when the excitation density approaches the cohesive
energy density, and a crater rim is formed at about six times that energy
density. The crater length scales roughly as the square root of the electronic
stopping power, and the crater width and depth seem to saturate for the largest
energy densities considered here. The number of ejected particles, the
sputtering yield, is shown to be much smaller than simple estimates based on
crater size unless the full crater morphology is considered. Therefore, crater
size can not easily be used to estimate the sputtering yield.Comment: LaTeX, 7 pages, 5 EPS figures. For related figures/movies, see:
http://dirac.ms.virginia.edu/~emb3t/craters/craters.html New version uploaded
5/16/01, with minor text changes + new figure
High failure rates of protease inhibitor-based antiretroviral treatment in rural Tanzania - a prospective cohort study
Poor adherence to antiretroviral drugs and viral resistance are the main drivers of treatment failure in HIV-infected patients. In sub-Saharan Africa, avoidance of treatment failure on second-line protease inhibitor therapy is critical as treatment options are limited.; In the prospective observational study of the Kilombero & Ulanga Antiretroviral Cohort in rural Tanzania, we assessed virologic failure (viral load ≥1,000 copies/mL) and drug resistance mutations in bio-banked plasma samples 6-12 months after initiation of a protease inhibitor-based treatment regimen. Additionally, viral load was measured before start of protease inhibitor, a second time between 1-5 years after start, and at suspected treatment failure in patients with available bio-banked samples. We performed resistance testing if viral load was ≥1000 copies/ml. Risk factors for virologic failure were analyzed using logistic regression.; In total, 252 patients were included; of those 56% were female and 21% children. Virologic failure occurred 6-12 months after the start of a protease inhibitor in 26/199 (13.1%) of adults and 7/53 of children (13.2%). The prevalence of virologic failure did not change over time. Nucleoside reverse transcriptase inhibitors drug resistance mutation testing performed at 6-12 months showed a positive signal in only 9/16 adults. No cases of resistance mutations for protease inhibitors were seen at this time. In samples taken between 1-5 years protease inhibitor resistance was demonstrated in 2/7 adults. In adult samples before protease inhibitor start, resistance to nucleoside reverse transcriptase inhibitors was detected in 30/41, and to non-nucleoside reverse-transcriptase inhibitors in 35/41 patients. In 15/16 pediatric samples, resistance to both drug classes but not for protease inhibitors was present.; Our study confirms high early failure rates in adults and children treated with protease inhibitors, even in the absence of protease inhibitors resistance mutations, suggesting an urgent need for adherence support in this setting
Skin testing in patients with hypersensitivity reactions to iodinated contrast media - a European multicenter study
BACKGROUND: Iodinated contrast media cause both immediate and nonimmediate hypersensitivity reactions. The aim of this prospective study was to determine the specificity and sensitivity of skin tests in patients who have experienced such reactions.
METHODS: Skin prick, intradermal and patch tests with a series of contrast media were conducted in 220 patients with either immediate or nonimmediate reaction. Positive skin tests were defined according to internationally accepted guidelines. Seventy-one never-exposed subjects and 11 subjects who had tolerated contrast medium exposure, served as negative controls.
RESULTS: Skin test specificity was 96-100%. For tests conducted within the time period from 2 to 6 months after the reaction, up to 50% of immediate reactors and up to 47% of nonimmediate reactors were skin test positive. For immediate reactors, the intradermal tests were the most sensitive, whereas delayed intradermal tests in combination with patch tests were needed for optimal sensitivity in nonimmediate reactors. Contrast medium cross-reactivity was more common in the nonimmediate than in the immediate group. Interestingly, 49% of immediate and 52% of nonimmediate symptoms occurred in previously unexposed patients. Many of these patients were skin test positive, indicating that they were already sensitized at the time of first contrast medium exposure.
CONCLUSIONS: These data suggest that at least 50% of hypersensitivity reactions to contrast media are caused by an immunological mechanism. Skin testing appears to be a useful tool for diagnosis of contrast medium allergy and may play an important role in selection of a safe product in previous reactors
Comparison of SMOS and SMAP Soil Moisture Retrieval Approaches Using Tower-based Radiometer Data over a Vineyard Field
The objective of this study was to compare several approaches to soil moisture (SM) retrieval using L-band microwave radiometry. The comparison was based on a brightness temperature (TB) data set acquired since 2010 by the L-band radiometer ELBARA-II over a vineyard field at the Valencia Anchor Station (VAS) site. ELBARA-II, provided by the European Space Agency (ESA) within the scientific program of the SMOS (Soil Moisture and Ocean Salinity) mission, measures multiangular TB data at horizontal and vertical polarization for a range of incidence angles (30-60). Based on a three year data set (2010-2012), several SM retrieval approaches developed for spaceborne missions including AMSR-E (Advanced Microwave Scanning Radiometer for EOS), SMAP (Soil Moisture Active Passive) and SMOS were compared. The approaches include: the Single Channel Algorithm (SCA) for horizontal (SCA-H) and vertical (SCA-V) polarizations, the Dual Channel Algorithm (DCA), the Land Parameter Retrieval Model (LPRM) and two simplified approaches based on statistical regressions (referred to as 'Mattar' and 'Saleh'). Time series of vegetation indices required for three of the algorithms (SCA-H, SCA-V and Mattar) were obtained from MODIS observations. The SM retrievals were evaluated against reference SM values estimated from a multiangular 2-Parameter inversion approach. The results obtained with the current base line algorithms developed for SMAP (SCA-H and -V) are in very good agreement with the reference SM data set derived from the multi-angular observations (R2 around 0.90, RMSE varying between 0.035 and 0.056 m3m3 for several retrieval configurations). This result showed that, provided the relationship between vegetation optical depth and a remotely-sensed vegetation index can be calibrated, the SCA algorithms can provide results very close to those obtained from multi-angular observations in this study area. The approaches based on statistical regressions provided similar results and the best accuracy was obtained with the Saleh methods based on either bi-angular or bipolarization observations (R2 around 0.93, RMSE around 0.035 m3m3). The LPRM and DCA algorithms were found to be slightly less successful in retrieving the 'reference' SM time series (R2 around 0.75, RMSE around 0.055 m3m3). However, the two above approaches have the great advantage of not requiring any model calibrations previous to the SM retrievals
Skin testing in patients with hypersensitivity reactions to iodinated contrast media - a European multicenter study
BACKGROUND: Iodinated contrast media cause both immediate and nonimmediate hypersensitivity reactions. The aim of this prospective study was to determine the specificity and sensitivity of skin tests in patients who have experienced such reactions.
METHODS: Skin prick, intradermal and patch tests with a series of contrast media were conducted in 220 patients with either immediate or nonimmediate reaction. Positive skin tests were defined according to internationally accepted guidelines. Seventy-one never-exposed subjects and 11 subjects who had tolerated contrast medium exposure, served as negative controls.
RESULTS: Skin test specificity was 96-100%. For tests conducted within the time period from 2 to 6 months after the reaction, up to 50% of immediate reactors and up to 47% of nonimmediate reactors were skin test positive. For immediate reactors, the intradermal tests were the most sensitive, whereas delayed intradermal tests in combination with patch tests were needed for optimal sensitivity in nonimmediate reactors. Contrast medium cross-reactivity was more common in the nonimmediate than in the immediate group. Interestingly, 49% of immediate and 52% of nonimmediate symptoms occurred in previously unexposed patients. Many of these patients were skin test positive, indicating that they were already sensitized at the time of first contrast medium exposure.
CONCLUSIONS: These data suggest that at least 50% of hypersensitivity reactions to contrast media are caused by an immunological mechanism. Skin testing appears to be a useful tool for diagnosis of contrast medium allergy and may play an important role in selection of a safe product in previous reactors
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