Low-level direct electrical current therapy for hepatic metastases. I. Preclinical studies on normal liver.

Low-level direct electrical current has shown promise as a potential therapeutic modality (direct current therapy; DCT) in the treatment of malignant disease, including metastases, but to date much experimental work has been empirical and has added little to our knowledge of the mechanisms involved. As a prerequisite to a clinical trial for metastases in the liver, we have employed an in vivo liver model to examine the quantitative and qualitative relationships between electrode polarity, charge and tissue necrosis. Two distinct regions of necrosis were induced, distinguishable histologically and by magnetic resonance imaging: (i) a cylindrical region of primary necrosis centred on the electrode, its volume directly proportional to the charge passed, but greater at the anode than cathode; and (ii) a wedge-shaped infarct, apex at the electrode and base extending to the liver edge. The extent of this infarct was again greater at the anode than the cathode, but showed a sigmoidal relationship with charge. Results indicate pH changes at the electrodes as likely mediators of tissue injury, but show also that significant distant ischaemic injury can occur as a consequence of primary damage. These findings should be considered when selecting tumours for possible direct current therapy and when determining the sites of electrode placement.

The effects of low-level direct current therapy on a preclinical mammary carcinoma: tumour regression and systemic biochemical sequelae.

Low-level direct electric current has been shown to be capable of destroying tumour tissue. Using an early-passage subcutaneous murine mammary carcinoma, the relationships between the volume of tumour destruction, charge and polarity have been examined. The results revealed a direct correlation between charge passed and absolute volume regression when the intratumoral electrode was made either an anode or a cathode. Tumour destruction for a given charge was significantly greater following anodic than cathodic treatment. A direct correlation was also observed between the percentage volume of prompt treatment-induced regression and the in situ end point of tumour growth delay. During the course of these experiments, a highly reproducible toxic effect was discovered, which has not been previously reported for this modality. An anodic charge greater than 10.6 coulombs or a cathodic charge greater than 21.6 coulombs resulted in 100% mortality at 24-72 h, while lower charges had no influence on mortality. Quantitative assays of a number of blood parameters showed that mortality was associated with serum electrolyte imbalances and appeared to be the result of the metabolic load of tumour breakdown products. These effects are similar to the tumour lysis or surgical crush syndromes and should not constitute a significant problem in clinical practice, where the tumour mass to total body mass ratio will normally be much smaller.

Reconsidering the measurement of ancillary service performance.

Prospective payment reimbursement systems have forced hospitals to review their costs more carefully. The result of the increased emphasis on costs is that many hospitals use costs, rather than margin, to judge the performance of ancillary services. However, arbitrary selection of performance measures for ancillary services can result in managerial decisions contrary to hospital objectives. Managerial accounting systems provide models which assist in the development of performance measures for ancillary services. Selection of appropriate performance measures provides managers with the incentive to pursue goals congruent with those of the hospital overall. This article reviews the design and implementation of managerial accounting systems, and considers the impact of prospective payment systems and proposed changes in capital reimbursement on this process.