Evaluation of temperature increase with different amounts of magnetite in liver tissue samples.

RATIONALE AND OBJECTIVES: The biologic effects of magnetically induced heating effects using iron oxide, magnetite, were examined in vitro in liver tissue samples as a first step toward potential applications in cancer therapy. METHODS: For the determination of the temperature profile around an iron oxide sample, a cylinder containing 170 mg of magnetite was constructed and placed into pureed liver tissue from pig, together with thermocouples of copper and constantan wires positioned at defined distances from it. Temperature measurements were performed during the exposure to an alternating magnetic field (frequency: 400 kHz; amplitude: approximately 6.5 kA/m) generated by a circular coil (90 mm of diameter). Moreover, variable amounts of magnetite (dissolved in approximately 0.2 mL physiologic saline) were injected directly into carrageenan gels. During the exposure to a magnetic field for 4 minutes the temperature increase was determined in the area of iron oxide deposition using a thermocouple. Additionally, variable amounts of magnetite were injected directly into isolated liver tissue samples (diameter: 20 mm; height: 30 mm) and exposed to a magnetic field for 2 minutes. The extent of the induced macroscopically visible tissue alterations (light brown colorations caused by heating) was examined by means of volume estimations. The degrees of cellular necrosis were investigated by histopathologic studies. RESULTS: The temperature profile around a magnetite cylinder revealed a significant decrease of temperature difference between the beginning and the end of heating, depending on increasing distance from the sample center. The extent of the temperature difference correlated with increasing heating time. No significant variations of temperature were observed at a distance of approximately 12 mm from the sample center. A good correlation (r = 0.98) between the injected amounts (31 to 200 mg) and the temperature increase since the start of heating (6.8-33.7 degrees C) in the area of iron oxide deposits was detected. The volume of damaged liver tissue was approximately seven times higher than the injected volume of iron oxide dispersion. Histologically different degrees of cellular necrosis were observed. CONCLUSIONS: The parameters determined in this article show that iron oxides are able to induce considerable heating effects in the surroundings. After an adequate optimization of the technical procedure, it is conceivable that heating properties of magnetites can be used in future cancer treatments.

The disruptive antisocial patient: management strategies.

As our society copes with increasing numbers of persons who exhibit criminal behaviors, hospital personnel also are encountering them in equally large numbers as they enter tertiary urban hospitals as victims of trauma with their injuries often complicated by alcohol or drug withdrawal. The nurse manager plays a significant role in coordinating strategies for managing the antisocial patient and can have a marked influence on containment of disturbing behaviors during the individual's hospitalization.

Failure to master early developmental tasks as a predictor of adaptation to cancer in the young adult.

The ability of young adults to adapt to living with a cancer diagnosis and to negotiate the healthcare system is influenced by their level of maturity. If adolescent developmental tasks have been unresolved or pathologically resolved, they are likely to be reenacted during the various stages of the malignancy. Retrospective review of case histories that illustrate the diverse ranges of adaptation to life-threatening illness indicates that success or failure in achieving ego autonomy and continuity in adolescence significantly influences the young adult's capacity to cope with the malignancy. Psychosocial assessment of the young adult patient and spouse, with attention to childhood, adolescent, and family history, will assist the oncology nurse in predicting the individual's capacity for adapting to the illness and complying with treatment. This developmental information will allow clinicians to modify interventions to compensate for earlier stage deficits.

Cardiovascular effects of a novel vasoactive antihypertensive agent, Ro 12-4713.

Ro 12-4713, an oxadiazolopyrimidine derivative, lowered blood pressure of conscious spontaneously hypertensive rats and renal hypertensive dogs in a dose-dependent manner from 10 to 100 mg/kg p.o. The antihypertensive effect was slow in onset, had a long duration of action and was not subject to the development of tachyphylaxis. Ro 12-4713 did not influence blood pressure in conscious normotensive rats, cats and dogs. Several observations suggest that metabolites formed from the inactive parent compound are responsible for the cardiovascular effects. A hemodynamic analysis in anesthetized dogs showed that Ro 12-4713 lowered blood pressure and peripheral vascular resistance. These effects were associated with an increase in cardiac output and flow in various vascular beds as well as with an increase in myocardial contractility. This pattern of hemodynamic activity together with the absence of effects on the autonomic neuroeffector system allow the classification of Ro 12-4713 as a vasoactive antihypertensive agent like e.g. hydralazine or minoxidil. However, in contrast to other vasoactive antihypertensives, Ro 12-4713 virtually did not produce tachycardia or water and sodium retention. Ro 12-4713 may represent a considerable improvement in current vasodilator antihypertensive therapy.