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Degradation kinetics for several peptides that bind to the major histocompatibility complex on antigen-presenting cells were determined in both human serum (HS; 25%) and synovial fluid (SF; 25%) from patients with rheumatoid arthritis to test whether therapeutic intervention of rheumatoid arthritis by direct intrasynovial injection is feasible (at least in terms of peptide stability). Controls consisted of enzymatically immature 10% fetal calf serum and peptidase-rich 5% liver homogenate (all diluted with RPMI-1040 tissue culture medium). Peptide half-lives ranged from approximately 4 to greater than 10,000 min, with most peptides showing half-lives of approximately 10-100 min. These studies show that, even though the populations of inflammatory and other cell types in SF and HS are different (and may, therefore, generate different peptidase profiles), the observed peptide stabilities in SF and HS are similar. This finding indicates that the effect of SF on peptide stability is similar to that of HS. 相似文献
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Human lymphocytes and Chinese hamster ovary (CHO) cells in culture were exposed for 12 1/2 hours to a magnetic resonance imaging apparatus with a 2.35-Tesla magnet and 100-MHz radio frequency emission. The cells were examined for cytogenetic damage manifested either as chromosome aberrations or sister chromatid exchanges (SCEs), which constitute very sensitive measures of genetic and cellular damage. In either unstimulated or stimulated human lymphocytes, as well as in exponentially growing CHO cells, no increase in either chromosome aberrations or SCEs was found as a result of exposure to these MR conditions. The data indicate that long-term exposure to MR imaging conditions far exceeding those to be found in the clinical situation does not cause cytogenetic damage. 相似文献
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A polymer system was developed for use in permanent inflation of detachable balloons, to avoid long-term reliance on the integrity of balloon shells or valve mechanisms. This system is based on 2-hydroxy-ethyl methacrylate (HEMA) as the monomer, in combination with a cross-linking agent and a water-soluble curing system. The low-viscosity, hydrophilic mixture can be exchanged through a small-bore catheter into a detachable balloon and polymerizes in 40-60 minutes at body temperature. Partially polymerized HEMA can cause vascular occlusion; hence, careful timing of balloon detachment is required. The evolution of the radiographic appearance of HEMA-filled balloons is predictable. The balloons remain radiopaque on plain radiographs as long as the balloon shell and valve mechanisms are competent. After rupture of the shell or failure of the valve mechanism, the balloons become invisible on plain radiographs but remain hyperattenuating on computed tomography scans. 相似文献
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GB Winter 《Archives of disease in childhood》1983,58(7):485-487
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