The effect of paraldehyde on intravenous tubing sets.

Paraldehyde is used in the treatment of status epilepticus, alcohol withdrawal, and delirium tremens. Because it is a solvent, concerns have been raised about infusing it through plastic intravenous tubing sets. In a three-phase study, 4% paraldehyde in 5% dextrose solution was analyzed over 24 hours for photodegradation, adsorption to polyvinylchloride- (PVC) and polyethylene- (PE) lined intravenous tubing, and the presence of di(2-ethylhexyl) phthalate (DEHP). Paraldehyde and DEHP samples were quantified by gas chromatography, and DEHP was confirmed by mass spectral analysis. On exposure to light for 24 hours, the concentration of paraldehyde decreased from 100 to 97%. This decrease is statistically significant but clinically insignificant. A 24-hour continuous infusion of paraldehyde through the two types of tubing revealed a decrease in concentration attributable to adsorption of 4% with PE and 13% with PVC tubing at 2 hours. In addition, there was no appreciable leaching of DEHP over 24 hours with either type of tubing. Concerns about paraldehyde's light instability and effects on tubing integrity appear to be unwarranted with commercially available intravenous administration sets.

Preparative isolation of plasmid DNA with sedimentation field flow fractionation.

Sedimentation field flow fractionation (SFFF) can be used to isolate plasmids preparatively from crude cellular lysates. Total purification time is about 3/4 day, including lysate preparation. The purity and yield of plasmids isolated by SFFF appear to be at least equivalent to those prepared by traditional methods. Molecular-weight data also are supplied rapidly by SFFF without the need for standards.

Sedimentation field flow fractionation of DNA's.

Sedimentation field flow fractionation (SFFF) is a method for purifying and providing mass or size distribution information on samples containing particulates or soluble macromolecules. Since SFFF separations are based on simple physical phenomena related to first principles, molecular weight (or particle sizes) can be determined without calibration standards. SFFF is a gentle technique suited for fractionating biomolecules. Studies with the fragile lambda DNA (molecular weight, 33 X 10(6] and smaller supercoiled plasmids have shown that these materials are not altered during SFFF separation; molecular weights and conformation remain unchanged, and biological activity is not reduced. Recoveries of nucleic acids approach 100 percent. Typically, components with about 20 percent difference in mass can be separated essentially to baseline if required. Fractionation time is usually independent of molecular weight, and separations often can be carried out within an hour.

Disturbance of pulmonary prostaglandin metabolism in fetuses of alloxan-diabetic rabbits.

[14C]Arachidonic acid conversion in lung homogenates of 28-day fetuses from control and alloxan-diabetic rabbits was studied. The major metabolites were 12-L-hydroxy-5,8,10,14-eicosatetraenoic acid and prostaglandin E2. Small amounts of 6-ketoprostaglandin F1 alpha, prostaglandin F2 alpha, and thromboxane B2 were also observed. Lung homogenates from fetuses of alloxan-diabetic rabbits convert significantly less [14C]arachidonic acid to prostaglandin E2, whereas all other metabolites were present in similar quantities compared to fetuses of non-diabetic rabbits. These studies suggest that the decreased arachidonic acid conversion to prostaglandin E2 could be partially responsible for the functional delay of lung maturation in offspring of alloxan-diabetic rabbits.