Corbicula fluminea rapidly accumulate pharmaceuticals from an effluent dependent urban stream.

Freshwater bivalve populations are stressed by watershed development at the global scale. Though pharmaceuticals released from wastewater treatment plant effluent discharges are increasingly reported to bioaccumulate in fish, an understanding of bioaccumulation in bivalves is less defined. In the present study, we examined accumulation of 12 target pharmaceuticals in C. fluminea during a 42 day in situ study in Pecan Creek, an effluent dependent wadeable stream in north central Texas, USA. Caged clams were placed at increasing distances (5 m, 643 m, 1762 m) downstream from a municipal effluent discharge and then subsampled on study days 7, 14, 28 and 42. Acetaminophen, caffeine, carbamazepine, diltiazem, diphenhydramine, fluoxetine, norfluoxetine, sertraline, desmethylsertraline, and methylphenidate were identified in C. fluminea whole body tissue homogenates via isotope dilution liquid chromatography-tandem mass spectrometry. Tissue concentrations ranged from low µg/kg (methylphenidate) to 341 µg/kg (sertraline). By study day 7, rapid and apparent pseudo-steady state accumulation of study compounds was observed in clams; this observation continued throughout the 42 d study. Notably, elevated bioaccumulation factors (L/kg) for sertraline were observed between 3361 and 6845, which highlights the importance of developing predictive bioaccumulation models for ionizable contaminants with bivalves. Future research is also necessary to understand different routes of exposure and elimination kinetics for pharmaceutical accumulation in bivalves.

[Intraepithelial phototherapeutic keratectomy and alcohol delamination for recurrent corneal erosions--two minimally invasive surgical alternatives]. / Intraepitheliale Phototherapeutische Keratektomie und Alkohol-Abrasio zur Therapie der rezidivierenden Erosio corneae - zwei minimalinvasive chirurgische Alternativen.

BACKGROUND: Phototherapeutic keratectomy (PTK) has become established as a successful therapy for recurrent corneal erosions. After epithelial debridement, Bowman's lamella and anterior stroma are ablated by the Excimer laser. We have evaluated two alternative stroma-sparing treatment options, intraepithelial PTK, and alcohol delamination. PATIENTS AND METHODS: All treatments were performed in the relapse-free period. 17 eyes with recurrent corneal erosions were treated with intraepithelial PTK: from the intact epithelium, 12 - 25 microm of tissue were ablated by the Excimer laser (group I). Alcohol delamination was performed in 13 eyes (group II). Follow-up time was between 6 months and 7 years (mean 4.2 years). RESULTS: Both methods turned out to be safe, no refractive changes were detectable. After intraepithelial PTK, we saw a cumulative recurrence rate of 12 % after 1 year, 18 % after 2 years, and 24 % after 3 years, and a temporary subepithelial scaring was seen. Alcohol delamination resulted in a recurrence rate of 15 % during the whole follow-up time (no statistically significant difference compared to intraepithelial PTK), showing no haze or scarring. CONCLUSION: Both minimally invasive, stroma-sparing methods were effective for the treatment of trauma-associated recurrent erosion. The ablation of Bowman's lamella or anterior stroma does not seem to be necessary. However, for basal membrane dystrophy, we recommend PTK after epithelial debridement for the partial ablation of Bowman's lamella.

Peritoneal mucinous cystadenocarcinoma of probable urachal origin: a challenging diagnosis.

This report describes the case of a mucinous cystadenocarcinoma of probable urachal origin that presented with mass effect, precipitating deep venous thrombosis and pulmonary embolism. The patient presented with acute symptoms of leg swelling, pain and dyspnoea, and a vague awareness of lower abdominal distension. Computer tomography showed a cystic mass closely related to the anterior abdominal wall and the superior aspect of the bladder. A 1500 cm(3) cyst adherent to the dome of the urinary bladder was resected on laparotomy. Partial cystectomy was not carried out in the belief that the cyst represented a benign lesion. Subsequent imaging has shown cystic changes in the anterior bladder wall, and the patient has been referred for partial cystectomy.

Assessment of toxicity reduction in wastewater effluent flowing through a treatment wetland using Pimephales promelas, Ceriodaphnia dubia, and Vibrio fischeri.

Effluent toxicity is regularly assessed with Ceriodaphnia dubia short-term chronic and Vibrio fischeri toxicity tests. Condition factor and hemotocrit of fish have recently been used to assess fish health following exposure to xenoestrogens in complex municipal effluents. To assess the ability of a treatment wetland to reduce or remove toxicity of a municipal effluent, we compared C. dubia and V. fischeri bioassays to Pimephales promelas responses in situ. Final whole effluent was diverted to a constructed wetland and effluent samples were taken daily from four sites, at incremental distances from the inflow, for a 3-week study. Overlapping 7-day C. dubia tests and V. fischeri assays were conducted with samples from each wetland site concurrent with a 3-week fish exposure. C. dubia survival and fecundity were significantly (< 0.0001) reduced at the inflow, but steadily improved with distance from the inflow. Fish condition and hematocrit were lower (alpha < 0.05) at wetland sites closer to the inflow than other wetland sites and laboratory controls. However, effluent toxicity was not detected by V. fischeri bioassays. Our findings indicate that 7-day C. dubia bioassays were most sensitive to effluent toxicity and suggest that other bioassays should be used concurrent with V. fischeri assays for municipal effluent toxicity testing.

Assessment of the estrogenicity and toxicity of a domestic wastewater effluent flowing through a constructed wetland system using biomarkers in male fathead minnows (Pimephales promelas rafinesque, 1820).

The toxicity and estrogenicity of a final treated municipal effluent was examined while flowing through a constructed wetland in north-central Texas, USA. Fish data were collected, and a baseline wetland characterization was performed to assess wetland treatment potential for these effluent properties. Vitellogenin (VTG), gonadosomatic index (GSI), hepatosomatic index (HSI), and secondary sexual characteristics were biomarkers used in fish models to assess aqueous estrogenicity. Biological indicators used to assess overall fish health included hematocrit and condition factor. Estrogenic nature of final sewage treatment works effluent was screened, concurrent with a three-week fish exposure, via gas chromatography/mass spectrometry for target estrogenic compounds, including 17beta-estradiol, ethynylestradiol, bisphenol A, nonylphenolic compounds, phthalates, and DDT. The VTG in Pimephales promelas was measured after exposure at four sites in a treatment wetland and was significantly elevated (p < 0.0001) in fish exposed at the inflow site. The GSIs were significantly less (alpha = 0.001) at the inflow site. At wetland sites closest to the inflow, secondary sexual characteristics, tubercle numbers, and fatpad thickness were less (alpha = 0.0001) than in laboratory controls. The HSIs and density of male breeding stripes were not significantly different from those of laboratory controls. However, elevated HSIs were found at the inflow site. Hematocrit and condition factors were both less (alpha = 0.001) in effluent-exposed fish at wetland sites closer to the inflow than in control fish or fish further downstream.

Decision-case mix model for analyzing variation in cesarean rates.

This article contributes a decision-case mix model for analyzing variation in c-section rates. Like recent contributions to the literature, the model systematically takes into account the effect of case mix. Going beyond past research, the model highlights differences in physician decision making in response to obstetric factors. Distinguishing the effects of physician decision making and case mix is important in understanding why c-section rates vary and in developing programs to effect change in physician behavior. The model was applied to a sample of deliveries at a hospital where physicians exhibited considerable variation in their c-section rates. Comparing groups with a low versus high rate, the authors' general conclusion is that the difference in physician decision tendencies (to perform a c-section), in response to specific obstetric factors, is at least as important as case mix in explaining variation in c-section rates. The exact effects of decision making versus case mix depend on how the model application defines the obstetric condition of interest and on the weighting of deliveries by their estimated "risk of Cesarean." The general conclusion is supported by an additional analysis that uses the model's elements to predict individual physicians' annual c-section rates.

A systematic approach to the validation of process control parameters for monoclonal antibody production in fed-batch culture of a murine myeloma.

A systematic approach to the validation of control ranges of control parameters for a cell culture process producing a monoclonal antibody is described. Specifically, the structure and functional activity of a monoclonal IgG1 antibody produced at the outer limits of numerical ranges of fed-batch culture control parameters such as pH and temperature were examined, with the aim of providing assurance that antibody produced under varying culture conditions was of consistent quality based on a carefully defined set of specifications. An experimental design was created using a half-fractional factorial design for fed-batch culture incorporating half of the thirty two possible combinations of five selected control parameters at high and low levels. Statistical analysis of all data gathered from the study allowed an assessment of the effects of the process control parameters at either high or low outer limits on fed-batch culture response variables such as growth rate and specific antibody productivity. Measured values for the responses of growth rate and specific antibody productivity throughout this study ranged from 0.22-0.44 d(-1) and 6.4-32 microg monoclonal antibody/10(6) cells/d respectively. Analytical characterisation of monoclonal antibody purified from each fed-batch culture considered the purity, structure and biological activity of the glycoprotein. All antibody preparations were identical to each other and to the current antibody reference standard or control. Glycosylation analysis of certain samples from the study demonstrated that the distribution of glycoforms of the antibody was not affected by the varying process control conditions of the fed-batch cultures.

Estimating pesticide exposure in tidal streams of Leadenwah Creek, South Carolina.

This article estimates the potential exposure of estuarine organisms to two pesticides (azinphosmethyl and fenvalerate) in a tidal stream of Leadenwah Creek near the Edisto River, South Carolina, during four runoff episodes. Exposure is calculated from simulation runs of the one-dimensional transport equation solved by an implicit finite difference method. Calibration was done for each episode by adjusting three conditions (runoff starting time, duration, and flow) and a correction to the dispersion coefficient in order to match the continuously measured salinity transients. First-order rate constants used by the fate component were calculated from half-life values reported in the literature. Baseline scenarios for each episode and each pesticide were derived by using the same conditions obtained in the salinity runs and adjusting the pesticide loading in order to mimic the few data points of measured pesticide concentrations. In all baseline scenarios, pesticide concentration rises following the initial burst of runoff (also noticeable as an abrupt drop in salinity) and then oscillates, forced by the tidal cycle. These oscillations are dominated by transport, while fate imposes a secular decaying trend. Ten additional scenarios for each episode were obtained from the baseline scenario by randomly varying three pesticide load parameters (starting time and duration of runoff, and pesticide discharge) using a Latin hypercubes design. Two exposure metrics were calculated from the simulated and the measured pesticide concentration: maximum and time average, which was obtained by integrating the curve and dividing by the time period. The metrics calculated from the baseline runs are relatively close to the data-derived metrics, because the baseline runs attempted to mimic the data. For each one of the two metrics and all pesticide-episode combinations, several statistics of the set of 11 scenarios were also calculated: minimum and maximum, mid-range, mean, standard deviation, and median. The mean +/- standard deviation interval of the simulation-derived value consistently brackets the data-derived value for the maximum metric, but not for the time-average metric. This may indicate that even if the maximum value is correctly captured in the field sample, the time-average exposure could be in error when calculated directly from the field data due to undersampling of the pesticide time series. The methodology developed here attempts to reconstruct the possible exposure from the sparse sampling of the pesticide concentration during the runoff episodes; only when the number of field samples is high and regularly spaced is it possible to have confidence in the reconstruction of the curve. The shape of the curve cannot be inferred from the field measurements alone; as expected, tidal movement makes the pesticide concentration swing up and down. This result has important implications because the biological community would be subject to repetitive pulses of exposure to the chemicals. The baseline simulations can be used to derive a pulse-exposure metric by calculating the sum of ratios of the time average of the threshold-exceeding concentrations to the time average of the toxic threshold during intervals of above-threshold concentration. This metric is species specific and extrapolates laboratory toxicity data in order to compare pulse exposure to mortality rates measured in the field.

Acute and chronic toxicity of azinphos-methyl to two estuarine species, Mysidopsis bahia and Cyprinodon variegatus.

The acute and chronic toxicity of azinphos-methyl (Guthion) was evaluated for two estuarine species in the laboratory. Mysids (Mysidopsis bahia) and sheepshead minnows (Cyprinodon variegatus) were selected as the representative invertebrate and vertebrate estuarine test species, respectively. The toxicological endpoints determined for each species included the 96-h LC50, the no-observed-effect concentration (NOEC), the maximum acceptable toxicant concentration (MATC), and the acute-to-chronic ratio. The 96-h LC50 value derived for sheepshead minnows (2.0 microg/L) was seven times higher than the 96-h LC50 value (0.29 microg/L) derived for mysids. The MATCs were 0.024 microg/L and 0.24 microg/L for the mysid and the sheepshead minnow, respectively. The estimated acute-to-chronic ratios were 12 for mysids and 8.3 for sheepshead minnows.