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J W Phillips

Publications and source records attributed to J W Phillips.

58 records · Page 4Linked to original sources
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Cell electroporation is a highly efficient method for introducing restriction endonucleases into cells.

Restriction endonucleases that make either blunt- or cohesive-end DNA double-strand breaks can induce chromosome aberrations. We have used cell electroporation with great success to permeabilize Chinese hamster ovary cells for the introduction of restriction enzymes. The introduction of restriction enzymes by this method resulted in extremely high frequencies (greater than 90%) of aberrant metaphase cells and also a dramatic decrease in cell survival, as measured by subsequent colony formation. Cell electroporation by itself caused no increase in aberrant chromosomes and had only a slight effect on cell survival.

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Some unexplained features of hepatic ethanol oxidation.

Ethanol is an excellent substrate for the liver, competing effectively for oxidation with other substrates such as fatty acids. Using isolated liver cells from fed and starved rats, we have found that ethanol strongly inhibits Krebs cycle oxidations, so that the combustion through the cycle of acetyl CoA, derived from fatty acids, is reduced more than 50%. In contrast, fatty acid beta-oxidation to acetyl CoA is inhibited only 20% in fed and fasted states. Ethanol was not antiketogenic. In the fed state, octanoate but not palmitate inhibited ethanol oxidation whereas in cells from fasted rats palmitate inhibited ethanol oxidation. Gluconeogenesis from lactate was reduced 50% in hepatocytes from fasted rats but oxygen consumption was unaffected. This paradoxical maintenance of oxygen consumption in a state where the only overt need for ATP synthesis is depressed, suggests that ethanol oxidation may not be exclusively coupled to ATP synthesis but also can be linked to other energy transducing processes.

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The effects of screw removal on bone strain in an idealized plated bone model.

An idealized plated bone model was used to test the hypothesis that selected screw removal could alter the bone strain field and be a viable treatment for stress protection osteoporosis. Eighteen bone screw modifications were evaluated for their effects on bone strain. The three variables studied were number, position, and length of screws. Removal of two or four bone screws from an eight hole plate significantly increased the strain per load on the bone model over the values with eight screws in the plate (p less than 0.05). The four screw configurations increased bone strain more than the six screw configurations. It also was shown that the position of screws in the plate could significantly alter the bone strain per load results. Removal of six bone screws from an eight hole plate also increased the bone strain per load, but to excess in some tests. In those configurations, the results were not statistically different from the unplated configuration. Replacement of the full length screws with eight half length screws that engaged only the near cortex significantly reduced bone strain per load as compared with eight bicortical bone screws.

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