Colorado Medical Research Center

ABSTRACT Idaho National Laboratory's Test Area North is the site of a trichloroethene (TCE) plume resulting from waste injections. Previous investigations revealed that TCE was being attenuated relative to two codisposed internal tracers, tritium and tetrachloroethene, with a half-life of 9 to 21 years. Biological attenuation mechanisms were investigated using a novel suite of assays, including enzyme activity probes designed for the soluble methane monooxygenase (sMMO) enzyme. Samples were analyzed for chlorinated solvents, tritium, redox parameters, primary substrates, degradation products, bacterial community methanotrophic potential, and bacterial DNA. The enzyme probe assays, methanotrophic enrichments and isolations, and DNA analysis documented the presence and activity of indigenous methanotrophs expressing the sMMO enzyme. Three-dimensional groundwater data showed plume-wide aerobic conditions, with low levels of methane and detections of carbon monoxide, a by-product of TCE cometabolism. The TCE half-life attributed to aerobic cometabolism is 13 years relative to tritium, based on the tracer-corrected method. Similarly, a half-life of 8 years was estimated for cis-dichloroethene (DCE). Although these rates are slower than most anaerobic degradation processes, they can be significant for large plumes. This investigation is believed to be the first documentation of intrinsic aerobic TCE and DCE cometabolism in an aquifer by indigenous methanotrophs.

A new intralesional sustained-release chemotherapy is under development as a treatment for condylomata acuminata; it is administered as an injectable gel that consists of fluorouracil and epinephrine with a purified bovine collagen as the gellant (fluorouracil/epinephrine gel). In this randomized, double-blind study, we evaluated the safety and efficacy of this intralesional treatment in 401 patients, using 2 active drug formulations (fluorouracil/epinephrine gel and fluorouracil gel alone) and a placebo. Each lesion was injected once a week for up to 6 weeks, and patients were followed up for 3 months. A total of 359 patients with 1926 condylomata underwent evaluation. For all lesions treated with fluorouracil/epinephrine gel, the complete response (CR) rate was 77%. For all patients treated with fluorouracil/epinephrine gel, the CR rate was 61%. The fluorouracil/epinephrine gel was significantly more effective (P < .002) in treating condylomata than the fluorouracil gel without epinephrine (CR rate, 43%); both were superior to placebo (CR rate, 5%). At 3 months after completion of treatment, recurrence rates in patients with CRs were as follows: fluorouracil/epinephrine gel group, 50%; fluorouracil gel group, 58%. No clinically significant drug-related systemic reactions occurred. Finally, the type and severity of local tissue reactions of patients with a positive pretreatment collagen skin test result (6/401 [1.5%]) were similar to those of patients with a negative collagen skin test result. The fluorouracil/epinephrine injectable gel is a safe and effective treatment for condylomata acuminata.