401 research outputs found
Differential diagnosis of true and symptomatic epilepsy
To research the features of true and symptomatic epilepsy, conduct differential diagnosis of these diseases. To find the main differences and similar features of true and symptomatic epilepsy to verify the diagnosis correctly and select the most optimized methods of therapy
Phase separation in fluids exposed to spatially periodic external fields
We consider the liquid-vapor type phase transition for fluids confined within
spatially periodic external fields. For a fluid in d=3 dimensions, the periodic
field induces an additional phase, characterized by large density modulations
along the field direction. At the triple point, all three phases (modulated,
vapor, and liquid) coexist. At temperatures slightly above the triple point and
for low (high) values of the chemical potential, two-phase coexistence between
the modulated phase and the vapor (liquid) is observed. We study this
phenomenon using computer simulations and mean-field theory for the Ising
model. The theory shows that, in order for the modulated phase to arise, the
field wavelength must exceed a threshold value. We also find an extremely low
tension of the interface between the modulated phase and the vapor/liquid
phases. The tension is of the order 10^{-4} kB T per squared lattice spacing,
where kB is the Boltzmann constant, and T the temperature. In order to detect
such low tensions, a new simulation method is proposed. We also consider the
case of d=2 dimensions. The modulated phase then does not survive, leading to a
radically different phase diagram.Comment: 11 pages, 14 figure
Differential diagnosis of true and symptomatic epilepsy
To research the features of true and symptomatic epilepsy, conduct differential diagnosis of these diseases. To find the main differences and similar features of true and symptomatic epilepsy to verify the diagnosis correctly and select the most optimized methods of therapy
Diagnostic Performance of a Lower-dose Contrast-Enhanced 4D Dynamic MR Angiography of the Lower Extremities at 3āT Using Multisegmental Time-Resolved Maximum Intensity Projections
Background
For peripheral artery disease (PAD), MR angiography (MRA) is a well-established diagnostic modality providing morphologic and dynamic information comparable to digital subtraction angiography (DSA). However, relatively large amounts of contrast agents are necessary to achieve this.
Purpose
To evaluate the diagnostic accuracy of time-resolved 4D MR-angiography with interleaved stochastic trajectories (TWIST-MRA) by using maximum intensity projections (MIPs) of dynamic images acquired with reduced doses of contrast agent.
Study Type
Retrospective.
Population
Forty adult PAD patients yielding 1088 artery segments.
Field Strength/Sequence
A 3.0āT, time-resolved 4D MR-angiography with TWIST-MRA and MIP of dynamic images.
Assessment
DSA was available in 14 patients (256 artery segments) and used as reference standard. Three-segmental MIP reconstructions of TWIST-images after administration of 3āmL of gadolinium-based contrast agent (Gadoteridol/ProhanceĀ®, 0.5āM) per anatomical level (pelvis, thighs, and lower legs) yielded 256 artery segments for correlation between MRA and DSA. Three independent observers rated image quality (scale: 1 [nondiagnostic] to 4 [excellent]) and the degree of venous overlay (scale: 0 [none] to 2 [significant]) for all segments. Diagnostic accuracy for the detection of >50% stenosis and artery occlusion was calculated for all observers.
Statistical Tests
Binary classification test (sensitivity, specificity, positive/negative predictive values, diagnostic accuracy). Intraclass correlation coefficients (ICCs), logistic regression analysis with comparison of areas under the receiver-operating-characteristics (ROC) curves (AUCs) with the DeLong method. BlandāAltman-comparison.
Results
High diagnostic performance was achieved for the detection of >50% stenosis (sensitivity 92.9% [84.3ā99.9% (95%-CI)] and specificity 98.5% [95.7ā99.8% (95%-CI)]) and artery occlusion (sensitivity 93.1% [77.2ā99.2% (95%-CI)] and specificity 99.1% [96.9ā99.9% (95%-CI)]). Inter-reader agreement was excellent with ICC values ranging from 0.95 to 1.0 for >50% artery stenosis and occlusion. Image quality was good to excellent for both readers (3.41āĀ±ā0.72, 3.33āĀ±ā0.65, and 3.38āĀ±ā0.61 [meanāĀ±āSD]) with good correlation between observer ratings (ICC 0.71ā0.81). No significant venous overlay was observed (0.06āĀ±ā0.24, 0.23āĀ±ā0.43 and 0.11āĀ±ā0.45 [meanāĀ±āSD]).
Data Conclusion
MIPs of dynamic TWIST-MRA offer a promising diagnostic alternative necessitating only reduced amounts (50%) of gadolinium-based contrast agents for the entire runoff vasculature.
Evidence Level
3
Technical Efficacy
Stage
Infrared polarimetry Anisotropy of polymer nanofibers
We present a straightforward and easily interpretable multi scale infrared IR spectroscopic characterization of anisotropy and arrangement of polymer nanofibers. Direct spectral interpretation of fiber bundles and single fibers with respect to their anisotropic properties is possible by applying non invasive IR polarimetry at defined polarization states with spatial resolutions from the macroscale a few mm down to the nanoscale a few 10 nm . A vivid relation is shown to exist between vibrational bands in s polarized reflection and absorption associated photothermal spectra measured by the AFM IR technique. Such a relation is a prerequisite for detailed discussions of IR spectra with respect to complex fiber structures and material
Doxorubicin loaded Polymeric Nanoparticulate Delivery System to overcome drug resistance in osteosarcoma
<p>Abstract</p> <p>Background</p> <p>Drug resistance is a primary hindrance for the efficiency of chemotherapy against osteosarcoma. Although chemotherapy has improved the prognosis of osteosarcoma patients dramatically after introduction of neo-adjuvant therapy in the early 1980's, the outcome has since reached plateau at approximately 70% for 5 year survival. The remaining 30% of the patients eventually develop resistance to multiple types of chemotherapy. In order to overcome both the dose-limiting side effects of conventional chemotherapeutic agents and the therapeutic failure incurred from multidrug resistant (MDR) tumor cells, we explored the possibility of loading doxorubicin onto biocompatible, lipid-modified dextran-based polymeric nanoparticles and evaluated the efficacy.</p> <p>Methods</p> <p>Doxorubicin was loaded onto a lipid-modified dextran based polymeric nano-system. The effect of various concentrations of doxorubicin alone or nanoparticle loaded doxorubicin on KHOS, KHOS<sub>R2</sub>, U-2OS, and U-2OS<sub>R2 </sub>cells was analyzed. Effects on drug retention, immunofluorescence, Pgp expression, and induction of apoptosis were also analyzed.</p> <p>Results</p> <p>Dextran nanoparticles loaded with doxorubicin had a curative effect on multidrug resistant osteosarcoma cell lines by increasing the amount of drug accumulation in the nucleus via Pgp independent pathway. Nanoparticles loaded with doxorubicin also showed increased apoptosis in osteosarcoma cells as compared with doxorubicin alone.</p> <p>Conclusion</p> <p>Lipid-modified dextran nanoparticles loaded with doxorubicin showed pronounced anti-proliferative effects against osteosarcoma cell lines. These findings may lead to new treatment options for MDR osteosarcoma.</p
Mutational Specificity of Ī³-Radiation-Induced GuanineāThymine and ThymineāGuanine Intrastrand Cross-Links in Mammalian Cells and Translesion Synthesis Past the GuanineāThymine Lesion by Human DNA Polymerase Ī·ā
ABSTRACT: Comparative mutagenesis of Ī³- or X-ray-induced tandem DNA lesions G[8,5-Me]T and T[5-Me,8]G intrastrand cross-links was investigated in simian (COS-7) and human embryonic (293T) kidney cells. For G[8,5-Me]T in 293T cells, 5.8 % of progeny contained targeted base substitutions, whereas 10.0 % showed semitargeted single-base substitutions. Of the targeted mutations, the G f T mutation occurred with the highest frequency. The semitargeted mutations were detected up to two bases 5 ā² and three bases 3 ā² to the cross-link. The most prevalent semitargeted mutation was a C f T transition immediately 5 ā² to the G[8,5-Me]T cross-link. Frameshifts (4.6%) (mostly small deletions) and multiple-base substitutions (2.7%) also were detected. For the T[5-Me,8]G cross-link, a similar pattern of mutations was noted, but the mutational frequency was significantly higher than that of G[8,5-Me]T. Both targeted and semitargeted mutations occurred with a frequency of ā¼16%, and both included a dominant G f T transversion. As in 293T cells, more than twice as many targeted mutations in COS cells occurred in T[5-Me,8]G (11.4%) as in G[8,5-Me]T (4.7%). Also, the level of semitargeted single-base substitutions 5 ā² to the lesion was increased and 3 ā² to the lesion decreased in T[5-Me,8]G relative to G[8,5-Me]T in COS cells. It appeared that the majority of the base substitutions at or near the cross-links resulted from incorporation of dAMP opposite the template base, in agreement with the so-called āA-ruleā. To determin
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