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P F Turner

Publications and source records attributed to P F Turner.

7 recordsLinked to original sources
PubMed1988

Future trends in heating technology of deep-seated tumors.

Hyperthermia techniques and equipment have developed into a level of sophistication requiring special training and operator skills. Recent advances electromagnetic and ultrasound heating techniques are multi-applicator arrays, both external and invasive. These arrays are most effective when individual channel power control can be utilized to improve the heating pattern control during treatment. A preview of future capabilities shows that more selective tumor heating is possible with the advanced equipment. The role of computer pretreatment planning is a valuable aid in operator training as well as optimization of parameters. The current development of regional heating is in the deep focal heating by external focused arrays. The SIGMA 60 cylindrical dipole array deep steerable focal zone is described and test data presented showing the selective focusing obtained. A small invasive targeting E-field sensor is used to optimize phase and amplitude of the array to improve the selective heating in the target zone. These patented techniques and devices are expected to reduce systemic toxicity and increase tumor temperatures with lower power input. Future equipment development is predicted to include many types of hyperthermia devices and techniques. This trend suggests that systems must be designed to simplify the operator's tasks and improve the heating pattern controls. The computer power and control will become much more important in these future systems.

Electromagnetic Phenomena↗
PubMed1984

Taxol-induced bundling of brain-derived microtubules.

Taxol has two obvious effects in cells. It stabilizes microtubules and it induces microtubule bundling. We have duplicated the microtubule-bundling effect of taxol in vitro and report preliminary characterization of this bundling using electron microscopy, sedimentation, and electrophoretic analyses. Taxol-bundled microtubules from rat brain crude extracts were seen as massive bundles by electron microscopy. Bundled microtubules sedimented through sucrose five times faster than control microtubules. Electrophoretic analysis of control and taxol-bundled microtubules pelleted through sucrose revealed no striking differences between the two samples except for a protein doublet of approximately 100,000 daltons. Taxol-induced microtubule bundling was not produced by using pure tubulin or recycled microtubule protein; this suggested that taxol-induced microtubule bundling was mediated by a factor present in rat brain crude extracts. Taxol cross-linked rat brain crude extract microtubules were entirely labile to ATP in the millimolar range. This ATP-dependent relaxation was also demonstrated in a more purified system, using taxol-bundled microtubules pelleted through sucrose and gently resuspended. Although the bundling factor did not recycle with microtubule protein, it was apparently retained on isolated taxol-stabilized microtubules. The bundling factor was salt extracted from taxol-stabilized microtubules and its retained activity was demonstrated in an add-back experiment with assembled phosphocellulose-purified tubulin.

Adenosine Triphosphate↗