1,326 research outputs found
The Effects of Thrombus, Thrombectomy and Thrombolysis on Endothelial Function
AbstractObjective: this study was undertaken to examine and compare the effects of thrombus, thrombectomy, and thrombolysis on endothelial function as measured by endothelium-dependent vasorelaxation (EDR). Methods: adult, male New Zealand white rabbits underwent ligation of the left common iliac to femoral artery to induce thrombosis and were then randomly assigned to one of five groups, n=6 in each. Group A consisted of ligation and thrombosis for 4 h. Group B underwent similar ligation for 4 h, but without intraluminal thrombus present. Following 4 h of ligation and thrombosis, Group C underwent thrombectomy while group D was treated with urokinase (UK), 4000 U/min for 30 min. Group E underwent UK infusion alone. The right external iliac artery served as control vessel in each group. All arteries were removed and endothelial function was determined by measuring EDR. Results: the presence of thrombus reduced EDR by 50% (group A) compared to control. Vessels with interrupted flow, but not exposed to thrombus, retained normal EDR (group B). Thrombectomy decreased EDR significantly (group C) compared to thrombolysis (group D) and control. UK did not significantly alter EDR (groups D, E).Conclusions: exposure of endothelium to thrombus significantly decreases EDR. EDR was not affected by interruption of blood flow in the absence of thrombus. Thrombectomy appeared to cause a further additive insult to the endothelium. In contrast, thrombolysis with UK preserved residual endothelial function. These data suggest that it is important to differentiate the effects of thrombus on endothelium from effects due to thrombectomy or thrombolysis when evaluating treatment modalities for arterial thrombosis
Oncolog, Volume 37, Issue 02, April-June 1992
The primacy of patient welfare Potential doubling time of tumors may be the key to accurate prognosis, appropriate treatment Cognitive deficits in survivors of childhood cancershttps://openworks.mdanderson.org/oncolog/1038/thumbnail.jp
Recommended from our members
Feasibility study and design concept for an orbiting ice-penetrating radar sounder to characterize in three-dimensions the Europan ice mantle down to (and including) any ice/ocean interface
This report presents a radar sounding model based on the range of current working hypotheses for the nature of Europa's icy shell.Institute for Geophysic
Transport coefficients in high temperature gauge theories: (II) Beyond leading log
Results are presented of a full leading-order evaluation of the shear
viscosity, flavor diffusion constants, and electrical conductivity in high
temperature QCD and QED. The presence of Coulomb logarithms associated with
gauge interactions imply that the leading-order results for transport
coefficients may themselves be expanded in an infinite series in powers of
1/log(1/g); the utility of this expansion is also examined. A
next-to-leading-log approximation is found to approximate the full
leading-order result quite well as long as the Debye mass is less than the
temperature.Comment: 38 pages, 6 figure
Leak Rate Quantification Method for Gas Pressure Seals with Controlled Pressure Differential
An enhancement to the pressure decay leak rate method with mass point analysis solved deficiencies in the standard method. By adding a control system, a constant gas pressure differential across the test article was maintained. As a result, the desired pressure condition was met at the onset of the test, and the mass leak rate and measurement uncertainty were computed in real-time. The data acquisition and control system were programmed to automatically stop when specified criteria were met. Typically, the test was stopped when a specified level of measurement uncertainty was attained. Using silicone O-ring test articles, the new method was compared with the standard method that permitted the downstream pressure to be non-constant atmospheric pressure. The two methods recorded comparable leak rates, but the new method recorded leak rates with significantly lower measurement uncertainty, statistical variance, and test duration. Utilizing this new method in leak rate quantification, projects will reduce cost and schedule, improve test results, and ease interpretation between data sets
Interleukin-7 deficiency in rheumatoid arthritis: consequences for therapy-induced lymphopenia
We previously demonstrated prolonged, profound CD4+ T-lymphopenia in rheumatoid arthritis (RA) patients following lymphocyte-depleting therapy. Poor reconstitution could result either from reduced de novo T-cell production through the thymus or from poor peripheral expansion of residual T-cells. Interleukin-7 (IL-7) is known to stimulate the thymus to produce new T-cells and to allow circulating mature T-cells to expand, thereby playing a critical role in T-cell homeostasis. In the present study we demonstrated reduced levels of circulating IL-7 in a cross-section of RA patients. IL-7 production by bone marrow stromal cell cultures was also compromised in RA. To investigate whether such an IL-7 deficiency could account for the prolonged lymphopenia observed in RA following therapeutic lymphodepletion, we compared RA patients and patients with solid cancers treated with high-dose chemotherapy and autologous progenitor cell rescue. Chemotherapy rendered all patients similarly lymphopenic, but this was sustained in RA patients at 12 months, as compared with the reconstitution that occurred in cancer patients by 3–4 months. Both cohorts produced naïve T-cells containing T-cell receptor excision circles. The main distinguishing feature between the groups was a failure to expand peripheral T-cells in RA, particularly memory cells during the first 3 months after treatment. Most importantly, there was no increase in serum IL-7 levels in RA, as compared with a fourfold rise in non-RA control individuals at the time of lymphopenia. Our data therefore suggest that RA patients are relatively IL-7 deficient and that this deficiency is likely to be an important contributing factor to poor early T-cell reconstitution in RA following therapeutic lymphodepletion. Furthermore, in RA patients with stable, well controlled disease, IL-7 levels were positively correlated with the T-cell receptor excision circle content of CD4+ T-cells, demonstrating a direct effect of IL-7 on thymic activity in this cohort
Thomson and Compton scattering with an intense laser pulse
Our paper concerns the scattering of intense laser radiation on free
electrons and it is focused on the relation between nonlinear Compton and
nonlinear Thomson scattering. The analysis is performed for a laser field
modeled by an ideal pulse with a finite duration, a fixed direction of
propagation and indefinitely extended in the plane perpendicular to it. We
derive the classical limit of the quantum spectral and angular distribution of
the emitted radiation, for an arbitrary polarization of the laser pulse. We
also rederive our result directly, in the framework of classical
electrodynamics, obtaining, at the same time, the distribution for the emitted
radiation with a well defined polarization. The results reduce to those
established by Krafft et al. [Phys. Rev. E 72, 056502 (2005)] in the particular
case of linear polarization of the pulse, orthogonal to the initial electron
momentum. Conditions in which the differences between classical and quantum
results are visible are discussed and illustrated by graphs
Determining the WIMP mass using the complementarity between direct and indirect searches and the ILC
We study the possibility of identifying dark matter properties from
XENON-like 100 kg experiments and the GLAST satellite mission. We show that
whereas direct detection experiments will probe efficiently light WIMPs, given
a positive detection (at the 10% level for GeV), GLAST
will be able to confirm and even increase the precision in the case of a NFW
profile, for a WIMP-nucleon cross-section
pb. We also predict the rate of production of a WIMP in the next generation of
colliders (ILC), and compare their sensitivity to the WIMP mass with the XENON
and GLAST projects.Comment: 32 pages, new figures and a more detailed statistical analysis. Final
version to appear in JCA
Diffuse inverse Compton and synchrotron emission from dark matter annihilations in galactic satellites
Annihilating dark matter particles produce roughly as much power in electrons
and positrons as in gamma ray photons. The charged particles lose essentially
all of their energy to inverse Compton and synchrotron processes in the
galactic environment. We discuss the diffuse signature of dark matter
annihilations in satellites of the Milky Way (which may be optically dark with
few or no stars), providing a tail of emission trailing the satellite in its
orbit. Inverse Compton processes provide X-rays and gamma rays, and synchrotron
emission at radio wavelengths might be seen. We discuss the possibility of
detecting these signals with current and future observations, in particular
EGRET and GLAST for the gamma rays.Comment: 13 pages, 5 figure
- …