Effects of intermittent exposure to aflatoxin B1 on DNA and RNA adduct formation in rat liver: dose-response and temporal patterns.

We studied the effects of intermittent exposure to aflatoxin B1 (AFB1) on hepatic DNA and RNA adduct formation. Fisher-344 male rats were fed 0.01, 0.04, 0.4, or 1.6 ppm of AFB1 intermittently for 8, 12, 16, and 20 weeks, alternating with 4 weeks of dosing and 4 weeks of rest. Other groups of rats were fed 1.6 ppm of AFB1 continuously for 4, 8, 12, and 16 weeks. Control rats received AFB1-free NIH-31 meal diet. AFB1-DNA and -RNA adducts were measured by HPLC with fluorescence detection. The data are presented as total DNA or RNA adducts. The DNA and RNA adduct levels increased or decreased depending on the cycles of dosing and rest. Rats removed from treatment 1 month after 1 or 2 dosing cycles (8 and 16 weeks of intermittent exposure) showed approximately a twofold decrease in DNA adduct levels and a two- to elevenfold decrease in RNA adduct levels compared with rats euthanized immediately after the last dosing cycle (12 and 20 weeks of intermittent exposure). Our data indicate that DNA and RNA adducts increased linearly, from 0.01 ppm to 1.6 ppm of AFB1 after 12 and 20 weeks of intermittent treatment. A linear dose response was also apparent for DNA but not for RNA adducts after 8 and 16 weeks of treatment. As biomarkers of exposure, AFB1-RNA adducts were three to nine times more sensitive than AFB1-DNA adducts but showed greater variability. These results suggest that binding of AFB1 to hepatic DNA is a linear function of the dose, regardless of the way this is administered. The dose-response relationship for RNA adducts depends on the length of the no-dosing cycles and on the turnover rate of RNA.     

Low-dose outpatient chemobiotherapy with temozolomide, granulocyte-macrophage colony stimulating factor, interferon-alpha2b, and recombinant interleukin-2 for the treatment of metastatic melanoma.

PURPOSE: The objective of this study was to further investigate the efficacy and safety of low-dose outpatient chemobiotherapy in patients with unresectable metastatic melanoma. PATIENTS AND METHODS: Thirty-one patients with histologically confirmed unresectable measurable metastatic melanoma were enrolled onto an open-label, multicenter phase II study. The treatment regimen consisted of oral temozolomide followed by subcutaneous biotherapy with granulocyte macrophage colony-stimulating factor, interferon-alfa, and recombinant interleukin-2 (rIL-2). RESULTS: Twenty-eight patients (90%) had M1c disease, and 58% had three or more sites of metastasis. Four patients (13%), all with M1c disease, had a complete response, and four patients had a partial response. The median progression-free survival was 4.9 months and the median overall survival was 13.1 months. Two patients (6%) developed CNS metastasis as the first site of disease progression, and 7 (23%) of 30 experienced CNS progression after receiving chemobiotherapy. A total of 112 cycles of therapy were administered. Toxicity occurred in 78% of the cycles and was grade 1 or 2 in the majority of cases and easily managed. Grade 4 toxicity occurred in 3% of the cycles. CONCLUSION: This low-dose chemobiotherapy combination produces clinical responses in patients with metastatic melanoma, even in those with M1c disease, is well tolerated, and allows home dosing. It offers a reasonable alternative to high-dose regimens, such as high-dose biochemotherapy or rIL-2 requiring prolonged periods of hospitalization, or single agent outpatient regimens, such as dacarbazine, which is usually not effective in patients with M1c disease. Furthermore, it may protect against the development of brain metastases.     

Insights into pediatric rhabdomyosarcoma research: Challenges and goals

Overall survival rates for pediatric patients with high‐risk or relapsed rhabdomyosarcoma (RMS) have not improved significantly since the 1980s. Recent studies have identified a number of targetable vulnerabilities in RMS, but these discoveries have infrequently translated into clinical trials. We propose streamlining the process by which agents are selected for clinical evaluation in RMS. We believe that strong consideration should be given to the development of combination therapies that add biologically targeted agents to conventional cytotoxic drugs. One example of this type of combination is the addition of the WEE1 inhibitor AZD1775 to the conventional cytotoxic chemotherapeutics, vincristine and irinotecan.     

Robotic radical hysterectomy in the management of gynecologic malignancies

Robotic surgery is being used with increasing frequency in gynecologic oncology. To date, 44 cases were reported in the literature of radical hysterectomy performed with robotic surgery. When comparing robotic surgery with laparoscopy or laparotomy in performing a radical hysterectomy, the literature shows that robotic surgery offers an advantage over the other 2 surgical approaches with regard to operative time, blood loss, and length of hospitalization. Future studies are needed to further elucidate the equivalence or superiority of robotic surgery to laparoscopy or laparotomy in performing a radical hysterectomy.     

Maternal Exposure to Trichloroethylene in Drinking Water and Birth-Weight Outcomes

An ecological epidemiological study was conducted with data obtained from an environmental dose-reconstruction study and the Arizona Birth Information Tapes. Before 1981, a portion of the city of Tucson water-distribution system was contaminated with trichloroethylene (i.e., < 5 micrograms per liter of water to 107 micrograms per liter of water). Target and comparison populations were selected with a Geographic Information System. Logistical-regression analysis revealed an association between maternal exposure to trichloroethylene via drinking water and very-low-birth-weight babies (i.e., < 1,501 grams) (odds ratio = 3.3; 95% confidence interval = 0.5, 20.6; and Wald chi-square p value = 0.2). No association was found between maternal exposure to trichloroethylene via drinking water and low birth weight or full-term low-birth-weight infants (gestational period > 35 wk and < 46 wk).