Brachytherapy for pediatric soft-tissue sarcoma.

PURPOSE: To review the use of brachytherapy (BRT) to treat soft-tissue sarcoma (STS) in pediatric patients at St. Jude Children's Research Hospital. METHODS AND MATERIALS: Thirty-one patients, median age 11 years (range 1-21 years) with Pediatric Oncology Group (POG) Grade 2-3 soft-tissue sarcoma (excluding rhabdomyosarcoma and Ewing's sarcoma) were treated with BRT initially (n = 27) or at the time of recurrence (n = 4) using I-125 or Ir-192 in a temporary (n = 29) or permanent implant (n = 2). Twelve patients were treated with BRT alone and the remaining 19 were treated with a combination of BRT and external beam irradiation (EBRT). The majority of patients had involved margins of resection (n = 20) and tumors less than 5 cm (n = 17). RESULTS: Twenty-seven patients were treated with BRT at the time of presentation. Among the 10 patients treated with BRT alone, one patient developed metastases (4 months) and died of metastatic disease (12 months after presentation); there were no local or regional failures among the remaining 9 patients. Among the 17 patients treated with a combination of BRT and EBRT, there was one local (17 months), two regional (both at 8 months), and 3 distant failures (12, 15, 66 months). The median survival for the surviving 25 patients was 34 months. Wound dehiscence, fibrosis/telangectasia, pigment changes, and cellulitis were the most common side effects. CONCLUSIONS: BRT is an excellent treatment option for pediatric patients with STS. Disease control may be achieved with a high rate of success when BRT is used alone or in combination with EBRT. BRT should be considered for patients with STS who require radiation therapy with the objective of reducing the dose to normal tissues and shortening the overall treatment time. Limb preservation, functional outcome, and toxicity assessment require careful assessment in a prospective study.

Effects of waterborne nitrite on phase I-II biotransformation in channel catfish (Ictalurus punctatus).

The effects of waterborne nitrite (3 mg/l NO2) on channel catfish were studied to evaluate changes in hematological parameters and phase I-II biotransformation in liver slices. Nitrite-exposed fish had significantly higher methemoglobin, blood and liver nitrite, and significantly lower pO2 than control fish. Total phase I-mediated metabolism of 7-ethoxycoumarin (EC) was not altered in nitrite-exposed fish compared with control fish (291 +/- 43 and 312 +/- 20 pmol/mg/h, respectively). However, phase II glucuronosyltransferase-mediated metabolism of 7-hydroxycoumarin (HC), both as a phase I metabolite of EC and as a parent substrate, was elevated in nitrite-exposed fish (204 +/- 17 and 1007 +/- 103 pmol/mg/h, respectively) as compared to control fish (149 +/- 14 and 735 +/- 87 pmol/mg/h) (P < 0.05). Sulfotransferase-mediated metabolism of HC (as a metabolite of EC and as a parent substrate) was not notably altered in nitrite-exposed fish (95 +/- 16 and 617 +/- 33 pmol/mg protein/h, respectively) as compared with control fish (118 +/- 24 and 575 +/- 55 pmol/mg/h, respectively). These studies indicate that in vivo nitrite exposure and associated changes in hematological parameters do not appear to affect hepatic phase I EC biotransformation in channel catfish. However, subtle but significant changes in phase II glucuronidation, but not sulfation activity, were observed. The mechanism of these alterations is unclear. However, the data suggest that environmentally realistic concentrations of nitrite may affect the dynamics of conjugative metabolism in exposed fish.

Evaluation of atrazine soil extraction methods for the determination by enzyme immunoassay and gas chromatography.

Four soil extraction methods were evaluated for the determination of atrazine and other s-triazines by ELISA and GC, using both field-treated and laboratory fortified samples. The most efficient recoveries for atrazine, simazine, and cyanazine from loam soil fortified at concentrations from 0.01 ppm to 1 ppm were obtained by mechanical wrist-action shaker (1 h) using methanol:water and solid phase extraction (SPE) cleanup (standard method). A handshaking extraction (1 min) with acetonitrile:water showed fairly good correlation with the standard extraction method and is suitable for field use with ELISA. Sonication using acetonitrile:water and SPE cleanup was the most efficient extraction method for the dealkylated metabolites (deisopropyl and deethyl atrazine) with recoveries higher than 60%. In general, supercritical fluid extraction (SFE) was as efficient as sonication and handshaking but was more variable. A guideline for validation of immunoassays and methods comparison is given. The sensitivity of the ELISA method was comparable to the GC and was both accurate and precise. Comparison of ELISA and GC determinations of 120 field soil samples and 40 laboratory spiked soil samples extracted with four different methods showed no false negatives or positives with excellent correlations and showed not significant differences (P > 0.05). An evaluation of the cost for GC and ELISA methods was also conducted.