Metabolism-Coupled Cell-Independent Acetylcholinesterase Activity Assay for Evaluation of the Effects of Chlorination on Diazinon Toxicity.

Drinking water quality guideline values for toxic compounds are determined based on their acceptable daily intake. The toxicological end point for determining the acceptable daily intake of most organophosphorus insecticides is inhibition of acetylcholinesterase (AChE). Although insecticides ingested with drinking water are partly metabolized by the liver before transport to the rest of the body, no current cell-independent AChE activity assay takes the effects of metabolism into account. Here, we incorporated metabolism into a cell-independent AChE activity assay and then evaluated the change in anti-AChE activity during chlorination of a solution containing the organophosphorus insecticide diazinon. The anti-AChE activities of solutions of diazinon or diazinon-oxon, the major transformation product of diazinon during chlorination, were dramatically changed by metabolism: the activity of diazinon solution was markedly increased, whereas that of diazinon-oxon solution was slightly decreased, clearly indicating the importance of incorporating metabolism into assays examining toxicity after oral ingestion. Upon chlorination, diazinon was completely transformed, in part to diazinon-oxon. Although diazinon solution without metabolism did not show anti-AChE activity before chlorination, it did after chlorination. In contrast, with metabolism, diazinon solution did show anti-AChE activity before chlorination, but chlorination gradually decreased this activity over time. The observed anti-AChE activities were attributable solely to diazinon and diazinon-oxon having been contained in the samples before metabolism, clearly suggesting that the presence not only of diazinon but also of diazinon-oxon should be monitored in drinking water. Further examination using a combination of tandem mass spectrometry and in silico site-of-metabolism analyses revealed the structure of a single metabolite that was responsible for the observed anti-AChE activity after metabolism. However, because this compound is produced via metabolism in the human body after oral ingestion of diazinon, its presence in drinking water need not be monitored and regulated.

Effect of chlorination on anti-acetylcholinesterase activity of organophosphorus insecticide solutions and contributions of the parent insecticides and their oxons to the activity.

Organophosphorus insecticides are known to be partly transformed to their respective oxons during the chlorination step of drinking water treatment. For most organophosphorus insecticides, the toxicological endpoint for determining acceptable daily intake levels is inhibition of acetylcholinesterase (AChE). Like the parent insecticides, oxons also inhibit AChE, so the presence of oxons in drinking water is also evaluated. However, no attention is paid to the possible presence of transformation products (TPs) other than oxons. In the present study, we determined whether the anti-AChE activity observed for chlorinated solutions of the organophosphorus insecticides malathion and methidathion could be solely attributed to the parent compounds and their oxons. Upon chlorination, both malathion and methidathion were immediately transformed to their oxons; the maximum transformation ratios were 60% and 30%, respectively, indicating that at least 40% and 70% of these compounds were transformed into other TPs. Before chlorination, malathion- and methidathion-containing solutions exhibited little to no anti-AChE activity, but the solutions showed strong activity after chlorination. The contributions of the parent insecticides and their oxons to the activities of the chlorinated samples were calculated from the concentrations of the compounds in the samples and dose-response curves for chemical standards of the compounds. For both the malathion-containing solution and the methidathion-containing solution, the calculated anti-AChE activities were almost the same as the observed activities at every chlorination time. This suggests that the observed activities could be attributed solely to the parent insecticides and their oxons, indicating that other TPs need not be considered.

INITIAL EXPERIENCE OF THE ENZALUTAMIDE TREATMENT FOR CASTRATION-RESISTANT PROSTATE CANCER.

(Objective) Enzalutamide is an oral androgen-receptor inhibitor that prolongs survival in men with castration-resistant prostate cancer (CRPC). We retrospectively evaluated clinical efficacy and safety of enzalutamide in CRPC. (Patients and methods) We reviewed clinical records of 73 patients who had received enzalutamide for the CRPC at Showa University and affiliated 7 hospitals. Enzalutamide was given at a dose of 160 mg/day, but some patients were treated at lower dose because of there age or poor performance status. Prostrate-specific antigen (PSA) response, prior docetaxel use and the previously administered agents were evaluated retrospectively. (Results) The median patients age was 77 years, the median Gleason score was 9 and the median PSA level at baseline was 26.9 ng/ml. The patients who had prior docetaxel use were 29 (39.7%) and the median of total docetaxel dose was 460 mg/body. The median number of total prior treatments (anti-androgens, Estramustine and steroid) was 3. Twenty seven (61.4%) patients with docetaxel-naïve achieved over 50% reduction of PSA level from baseline, but only 7 (24.1%) in patients previously treated with docetaxel. The most common adverse events included fatigue (24.7%), anorexia (24.7%) and the nausea (16.4%). We found a small proportion of responders to enzalutamide experienced a PSA flare. (Conclusion) Our results of the use of Enzaltamide for CRPC were similar with previous reports. PSA flare was found in some patients with CRPC who responded to enzaltamide. It should be noted that this possible PSA flare phenomenon.

Successful management by provocative angiography and endovascular stent of Ureteroarterial fistula in a patient with a long-term indwelling ureteral stent.

We present the clinical course of a ureteroiliac arterial fistula in a patient who had been managed by ureteral stenting for 8 years for severe ureteral stricture after abdominoperineal resection with pelvic irradiation for advanced rectal cancer. A multidisciplinary team approach including provocative angiography and an endovascular stent saved the life of the patient. Ureteroarterial fistula is a rare complication of a long-term indwelling ureteral stent that is potentially fatal unless a prompt diagnosis and adequate therapy are provided. Heightened awareness and a high index of suspicion for this condition are required to make an early diagnosis.

Detection of circulating urothelial cancer cells in the blood using the CellSearch System.

BACKGROUND: Circulating tumor cells (CTCs) have been shown to aid in the therapeutic management of patients. But, only a few attempts have been made at the detection of urothelial cancer cells in the blood. The purpose of this study was to test the hypothesis that CTCs are detected in patients with urothelial cancers using newly developed CellSearch Assay. METHODS: Firstly, the bladder cancer cell lines were used to evaluate the reagents for immunocytochemical detection. After, mixed with peripheral blood mononuclear cells (PBMCs) of healthy volunteers, bladder cancer cells were stained with antibodies then multiparameter flow cytometric analysis was performed for the identification of bladder cancer cells in the PBMCs. Secondary, recovery of known numbers of spiked bladder cancer cells from whole blood was examined using CellSearch Assay. Finally, blood samples from nonmetastatic and metastatic urothelial cancer patients were investigated for CTC detection using CellSearch Assay. RESULTS: 1: Flow cytometric analysis revealed that it is possible to identify bladder cancer cells in PBMCs. 2: Sensitivity examination for detection of urothelial cancer cells with CellSearch Assay: Single regression analysis of the spiked number of cells vs. the recovered number of cells yielded a good correlation in this experiment. 3: Urothelial cancer cells were detected in 8 of fourteen patients (57.1%) with distant metastasis. Despite, no patient with nonmetastatic urothelial cancers showed positive result for this assay. CONCLUSION: This is the first report of attempt to detect circulating urothelial cancer cells in the peripheral blood of the patients with metastatic and nonmetastatic urothelial cancers by CellSearch Assay.