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Ferrite particles for bowel contrast in MR imaging: design issues and feasibility studies 总被引:1,自引:0,他引:1
Diverse materials with varying physical and magnetic properties have been evaluated as gastrointestinal contrast agents for magnetic resonance (MR) imaging. Uniform marking of the small bowel remains the greatest challenge. Ferrites are magnetically active iron oxide particles that are miscible with water and cause loss of signal on MR images. The decrease in MR signal intensity produced by ferrites occurs with a wide range of iron concentrations (0.1-10 mM) and with both T1- and T2-weighted pulse sequences. These effects of ferrites are explained by predominant T2 shortening with negligible T1 effects. The ferrite preparation used in this study was stable in vitro, with little iron solubilized by acid. Intragastric administration of ferrite (5 mg of iron per kg in 6 ml) routinely marked the small bowel of rats. The authors conclude that ferrites represent a promising new class of contrast agents for gastrointestinal MR imaging. 相似文献
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Tetrahydrocannabinol vs. prochlorperazine. The effects of two antiemetics on patients undergoing radiotherapy 总被引:1,自引:0,他引:1
The authors tested the effectiveness of orally administered delta-9-tetrahydrocannabinol (THC) as compared to prochlorperazine for the alleviation of symptoms, such as vomiting and nausea, experienced by patients receiving radiotherapy. The test subjects rated the severity of their illness, as well as the extent of their subsequent moods, their level of concentration, their amount of physical activity, and their desire for social interaction. They chose the drug they preferred and recorded its side effects. The use of THC was slightly more beneficial than the use of prochlorperazine. 相似文献
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Expression of the proliferation-associated nucleolar antigen p120 was studied by flow cytometry in human quiescent and phytohemagglutinin-stimulated lymphocytes, as well as in human lymphocytic (MOLT-4) and promyelocytic (HL-60) cell lines. Bivariate analysis of p120 and DNA content made it possible to correlate p120 expression with cell position in the cycle. Proliferating lymphocytes and MOLT-4 and HL-60 cells had a similar pattern of p120 expression. Populations of G1 cells, in all three cell types, were very heterogenous with respect to p120, and a threshold in G1 was observed. The cells with a p120 level below the threshold value did not enter S phase. An increase in p120 was observed during progression through S phase, and the antigen was maximally expressed in G2 cells. The p120/DNA content ratio, however, was highest in late G1 cells (G1B) and was declining during S and G2. The data thus suggest that p120 may be degraded during mitosis and that the postmitotic cells inherit little, if any, of this protein; the antigen then accumulates predominantly during G1, and must reach a threshold level to enable the cells to enter S phase. Antigen p120 could not be detected in noncycling lymphocytes nor in HL-60 cells induced to myeloid differentiation by growth in the presence of dimethyl sulfoxide. Treatment of MOLT-4 cells with pharmacological concentrations of methotrexate, camptothecin, or teniposide induced cell arrest in S or G2; expression of p120 in the arrested cells was unchanged from that of untreated MOLT-4 controls at the same phase of the cycle. The level of p120 was minimal in MOLT-4 or HL-60 cells arrested in M phase by vinblastine, but vinblastine had no effect on p120 fluorescence of interphase cells. Camptothecin or teniposide induced apoptosis selectively in S phase of HL-60 cells; apoptotic cells from camptothecin-treated cultures, however, despite the marked nucleolysis, still expressed p120. The data on the drug-treated cells indicate that the p120 level in tumors of patients may be used as a marker of tumor/malignancy even in clinical samples obtained during treatment. 相似文献
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Eleven high risk fetuses between 32 and 37 menstrual weeks gestational age were examined by magnetic resonance (MR) imaging. Serial obstetrical sonograms, birth weights, and serial postnatal examinations were obtained in all subjects. Sagittal MR spin echo images obtained using TR = 0.5 sec and TE = 28 msec were useful for assessing subcutaneous fat. Prospective estimates of fetal fat stores correlated with neonatal outcome better than sonographic measurements of fetal growth parameters or actual birth weight. MR appears to be a safe and useful technique that offers information complementary to obstetrical sonography when IUGR is suspected. 相似文献