Determinants of variability in acute to chronic toxicity ratios for aquatic invertebrates and fish.

Variability in acute to chronic ratios (ACRs; median lethal or effect concentration divided by chronic value) has been of continuing interest in aquatic toxicology because of the reliance on ACRs to estimate chronic toxicity for chemicals and species with known acute toxicity data but with limited or no information for chronic toxicity. To investigate the variability and significant differences in ACRs, an extensive data set was compiled of 456 same-species pairs of acute and maximum acceptable toxicant concentrations for metals, narcotics, pesticides, and other organic chemicals. The overall median value for 456 aquatic invertebrate and fish ACRs analyzed in the present study was 8.3, with a 16,000-fold range in values (1.1-18,550) and a 32-fold range in 10th and 90th percentile values (2.5-79.5). Median ACRs for taxa, ambient habitat media, chronic test end point, and chemical mode of action (MOA)/class categories generally were similar but, in some cases, extremely variable (ranges of 1 to >10,000). No significant differences (p

Image-guided percutaneous radiofrequency ablation for osteoid osteomas.

The authors present a retrospective analysis of the technical and clinical successes, complications, and clinical follow-up of image-guided percutaneous radiofrequency (RF) ablation of osteoid osteomas. Nine patients with osteoid osteomas underwent image-guided localization of osteoid osteomas. Outpatient percutaneous therapy (13 procedures) was performed under general anesthesia after image-guided localization of the nidus. Initial technical success was achieved in seven of nine patients. Two initial technical and clinical failures occurred early in this experience because of failure to adequately enter the nidus with use of fluoroscopic imaging alone. Clinical success was achieved in eight of nine patients. No major immediate or delayed complications were observed.

Pelvic congestion syndrome (pelvic venous incompetence): impact of ovarian and internal iliac vein embolotherapy on menstrual cycle and chronic pelvic pain.

PURPOSE: The purpose of this study was to analyze the impact of transcatheter embolotherapy on pain perception and menstrual cycle in women with chronic pelvic pain caused by the presence of ovarian and pelvic varices (ie, women with pelvic congestion syndrome or pelvic venous incompetence). MATERIALS AND METHODS: From July 1998 to August 2000, 56 patients (mean age, 32.3 y) were treated for chronic pelvic pain. Diagnostic venography of the ovarian veins was followed by transcatheter embolotherapy with a sclerosing agent and coils. A second session was completed to embolize the internal iliac veins in 43 of 56 patients. Visual analog scales (VAS) used to measure pain were administered before embolization and at 3-, 6-, and 12-month follow-up. Questionnaires regarding menstrual history were used as part of the postprocedural analysis. RESULTS: Percutaneous transcatheter embolotherapy of ovarian and pelvic varices was technically successful in 56 of 56 patients (100%); three patients developed recurrent varices, two of whom were treated with repeat transcatheter embolotherapy. Two patients, early in the experience, had complications in which coils placed in the internal iliac veins embolized to the pulmonary circulation; the coils were snared without clinical sequelae. On the VAS, the mean baseline pain level was 7.8 (range, 3.2-9.8; n = 56); at 3-month follow-up, it was 4.2 (range, 0.0-7.2; n = 56); at 6 months, 3.8 (range, 0.0-6.7; n = 41); and at 12 months, 2.7 (range, 0.0-6.9; n = 32). Differences were significant (P <.001) between baseline pain levels and those at all follow-up intervals (ie, 3, 6, and 12 months). The mean decrease in VAS was 5.1 (65% decrease). The clinical follow-up in this series ranged between 6 and 38 months; the mean was 22.1 months. Regarding the impact of embolization on menstruation, all 24 patients responding to questionnaires indicated no change in menstrual cycle. CONCLUSION: For patients with ovarian/internal iliac varices, transcatheter embolotherapy provides a nonsurgical treatment option. There is a significant decrease in pain based on VAS without any notable impact on menstrual cycle.