Do site-specific radiocarbon measurements reflect localized distributions of 14C in biota inhabiting a wetland with point contamination sources?

Duke Swamp is a wetland ecosystem that receives (14)C via a groundwater pathway originating from a waste management area on Atomic Energy Canada Limited's Chalk River Laboratories site. This groundwater reaches the surface of the swamp, resulting in relatively high (14)C levels over an area of 146 m(2). The objective of this study was to quantify (14)C concentrations in flora and fauna inhabiting areas of Duke Swamp over the gradient of (14)C activity concentrations in moss to determine whether (14)C specific activities in receptor biota reflect the localized nature of the groundwater source in the swamp. Representative receptor plants and animals, and corresponding air and soil samples were collected at six sites in Duke Swamp with (14)C specific activities in air that ranged from 1140 to 45,900 Bq/kg C. In general, it was found that specific activities of (14)C in biota tissues reflected those measured in environmental media collected from the same sampling site. The findings demonstrate that mosses could be used in monitoring programs to ensure protection of biota in areas with elevated (14)C, negating the need to capture and euthanize higher organisms.

Phase I trial of thermochemotherapy for brain malignancy.

High-grade primary and refractory brain tumors and metastases to the brain from other primary sites are associated with a grave prognosis. Treatment, usually palliative, consists of some combination of surgery, radiation, and chemotherapy. Recently, noninvasive hyperthermia by magnetic-loop induction has been safely used to treat patients with advanced cancer in extracranial sites. Both disease regression and disease stabilization have been observed. This technique was recently applied to brain tumors in an animal model, and its safety was again demonstrated. As a result, a Phase I trial of noninvasive localized hyperthermia in combination with intravenous chemotherapy has been carried out in ten patients whose primary or metastatic brain tumors failed to respond to standard therapy. Ten patients underwent 23 thermochemotherapy sessions using the magnetic-loop induction device. The median, maximum temperature of normal brain after 1 hour of hyperthermia was 41.1 degrees C (range, 38.6 degrees C-43.4 degrees C); the median, maximum temperature of brain tumor was 42.5 degrees C (range, 38.8 degrees C-46.3 degrees C) (P less than 0.01). The temperatures of both the normal brain and brain tumor were obtained during 18 treatments. The tumor temperature was greater than the normal brain temperature in 15 of 18 treatments. In 78% of the treatments, the measured tumor temperature reached at least 42 degrees C, whereas the normal brain reached 42 degrees C in only 13% of the treatments. These data demonstrate the "selective inability" of brain tumor tissue to dissipate heat. Vital signs, intracranial pressure, and neurologic status were monitored throughout the hyperthermia treatments. No mortality or increase in chemotherapeutic toxicity could be attributed to the thermochemotherapy. In addition, there were no local complications or permanent neurologic complications. Two patients with elevated intracranial pressure before therapy had transient neurologic deficits that may have been exacerbated by the hyperthermia. It is concluded that this new, noninvasive modality not only produced effective intracranial tumor heating, but could be performed safely with the proper precautions. Phase II trials are warranted.