Comparison of selective cytotoxicity of alkyl lysophospholipids

Alkyl lysophospholipids have been shown to be cytooxic to a number of neoplastic tissues. One, ET-18-OCH₃, has been used to selectively purge leukemic cells from mixtures with normal marrow progenitor cells,in vitro andin vivo. We have measured the 50% inhibitory (IC₅₀) effect of a series of ether, lipids (EL) on leukemic cells (HL60, K562, Daudi, KG-1, KG-1a) and normal marrow progenitor cells. Cells were incubated with varying concentrations of EL for 4 hr and assayed for viability, [³H]thymidine incorporation and clonogenicity in semi-solid media. The effect on protein kinase C (PKC) activity was assayed for each compound. Compounds tested included three glycerophosphocholine analogs-ET-18-OCH₃, ET-16-NHCOCH₃, and BM 41.440. In addition, a lipoidal amine, CP 46665, an ethyleneglycolphospholipid, AEPL, and four single chain alkylphosphocholine analogs, HePC₂, HePC₃, HePC₄ and HePC₆ were also tested. During the period of incubation, the cells remained viable (>70%) as judged by trypan blue dye exclusion. The glycerophosphocholines were the most active and showed the highest therapeutic index. The lipoidal amine was active, but toxic to normal marrow progenitor cells. The ethyleneglycolphospholipid was active against HL60, but not against the other cell lines. The single chain alkylphosphocholine analogs were less active. All of the compounds inhibited PKC activity; however, the glycerophosphocholines were the most inhibitory. Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl Ether Lipids, Tokyo, Japan, May 1989.     

Ba-eu (barium-europium)

Several thermodynamic models for calculating binary phase diagrams published in the literature have been reevaluated. Problems in some of these models are already evident in the models themselves and may also be seen in the resulting calculated phase diagrams. When a calculation is attempted, thermodynamic models with quite different formulations may result in very similar proposed phase diagrams. In such cases, if experimental data of a binary phase diagram can be represented reasonably well by several different thermodynamic models, a simpler model often provides the clearest insight into the basic properties of the system. If a calculated phase diagram results in unusual phase relationships, the adopted thermodynamic model may be inappropriate or may involve unrealistic parameters. If the thermodynamic model is clearly unrealistic and yet the calculated phase diagram appears to be normal, errors in calculation or in interpretation may be suspect. Various examples of unlikely combinations of thermodynamic models and phase diagrams are discussed.     

Pu-Zr (plutonium-zirconium)

Journal of Phase Equilibria -     

Self-identification algorithm for zeolite-based thermal capacity gas sensor

Microsystem Technologies - We demonstrate a new operation mode of thermal gas sensor based on thermal capacity extraction with identification algorithm. The system is a silicon microstructure...     

Surface degradation of polyamide nanocomposites caused by partial discharges using IEC (b) electrodes

Partial discharge (PD) degradation of polyamide both without nanoscale fillers (nanofillers) and with 2,4 and 5 wt% additions of nanofillers was investigated. Such materials were subjected to PDs using the IEC (b) electrodes for evaluation. Comparisons were made as to the surface roughness observed by scanning electron microscopy and atomic force microscopy. It was found that the change in the surface roughness is far smaller in specimens with nanofillers than those without nanofillers, and that the 2 wt% addition is sufficient for improvement of the surface roughness. Furthermore, it was elucidated that the difference of surface roughness of the degraded area due to PDs among the specimens originates from the difference in their crystalline structures. These results indicate that polyamide nanocomposite is more resistance to PDs than polyamide without nanofillers.