The characterization of composite agarose/hydroxyethylcellulose matrices for the separation of DNA fragments using capillary electrophoresis.

Mixtures of the polysaccharide derivatives, 19% hydroxyethylated SeaPrep agarose (SP-AG) and hydroxyethylcellulose (HEC), in aqueous buffer solutions are applied for the first time to the separation of DNA fragments using capillary electrophoresis (CE). These matrices form unique size-sieving networks that allow the separation of a wide size range of DNA fragments in a single analysis. Relative to their homogeneous counterparts, the composite separation matrices provide enhanced selectivity properties of DNA fragments, especially for fragments greater than 1000 base pairs (bp) in length. Additionally, the effects on separation performance of capillary temperature, the incorporation of a DNA intercalator, and applied field strength are demonstrated. Solution viscosity measurements of the homogeneous and composite matrix solutions were made in order to establish the entanglement threshold concentrations for the unique size-sieving solutions. The relatively low solution viscosities of the composite separation matrices allow reproducible replacement of the separation matrix between analyses. The mechanism of separation of DNA fragments for the composite matrices is proposed.

67Ga-citrate distribution in solid hepatoma 22.

The intracellular distribution of 67Ga was studied in solid hepatoma 22 implanted in C3Ha/6 mice and in normal liver tissue from the same animals at different time intervals. The tissues were fractionated according to differential centrifugation principles, and subcellular fractions were isolated consecutively. The enzyme activities and the accumulation of 67Ga were determined in each fraction. The subcellular distribution of 67Ga in the tumor tissue was different compared with normal liver; in tumor it was found mainly in the nuclear fraction and this distribution was independent of time, but in normal liver the accumulation was mainly in the mitochondrial fraction, this was time-dependent and the maximal uptake was found 48 h after 67Ga administration.