Related Articles An ecological risk assessment of the acute and chronic effects of the herbicide clopyralid to rainbow trout (Oncorhynchus mykiss). Arch Environ Contam Toxicol. 2009 Nov;57(4):725-31 Authors: Fairchild JF, Allert AL, Feltz KP, Nelson KJ, Valle JA Clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) is a pyridine herbicide frequently used to control invasive, noxious weeds in the northwestern United States. Clopyralid exhibits low acute toxicity to fish, including the rainbow trout (Oncorhynchus mykiss) and the threatened bull trout (Salvelinus confluentus). However, there are no published chronic toxicity data for clopyralid and fish that can be used in ecological risk assessments. We conducted 30-day chronic toxicity studies with juvenile rainbow trout exposed to the acid form of clopyralid. The 30-day maximum acceptable toxicant concentration (MATC) for growth, calculated as the geometric mean of the no observable effect concentration (68 mg/L) and the lowest observable effect concentration (136 mg/L), was 96 mg/L. No mortality was measured at the highest chronic concentration tested (273 mg/L). The acute:chronic ratio, calculated by dividing the previously published 96-h acutely lethal concentration (96-h ALC(50); 700 mg/L) by the MATC was 7.3. Toxicity values were compared to a four-tiered exposure assessment profile assuming an application rate of 1.12 kg/ha. The Tier 1 exposure estimation, based on direct overspray of a 2-m deep pond, was 0.055 mg/L. The Tier 2 maximum exposure estimate, based on the Generic Exposure Estimate Concentration model (GEENEC), was 0.057 mg/L. The Tier 3 maximum exposure estimate, based on previously published results of the Groundwater Loading Effects of Agricultural Management Systems model (GLEAMS), was 0.073 mg/L. The Tier 4 exposure estimate, based on published edge-of-field monitoring data, was estimated at 0.008 mg/L. Comparison of toxicity data to estimated environmental concentrations of clopyralid indicates that the safety factor for rainbow trout exposed to clopyralid at labeled use rates exceeds 1000. Therefore, the herbicide presents little to no risk to rainbow trout or other salmonids such as the threatened bull trout. PMID: 19777152 [PubMed - indexed for MEDLINE]
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An ecological risk assessment of the acute and chronic effects of the…
Related Articles Therapy modifications and low-density lipoprotein cholesterol goal attainment rates associated with the initiation of generic simvastatin. Curr Med Res Opin. 2010 Jan;26(1):121-8 Authors: Willey VJ, Bullano MF, Shoetan NN, Gandhi SK OBJECTIVE: The availability of generic simvastatin has changed the relative cost structure within the statin marketplace and has been associated with third-party payer changes to formularies and statin utilization policies. The current study examines simvastatin therapy modification patterns and associated low-density lipoprotein cholesterol (LDL-C) goal attainment rates. METHODS: This retrospective, observational study utilized administrative claims linked to laboratory result data from a national health plan. Patients newly initiated on generic simvastatin from January 2007 to March 2008 were identified. National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) risk categories and goal LDL-C targets were assigned. Simvastatin dose titrations and switches to other statins were described, as were changes in LDL-C values and NCEP ATP III goal attainment rates both before and after therapy modifications. RESULTS: Of the 1654 patients newly initiated on simvastatin, 84% had no simvastatin therapy modification in the > 1-year follow-up period. For patients with no therapy modification, 54.4% did not achieve their LDL-C NCEP ATP III goal at their first lipid panel and goal attainment was strongly associated with the level of cardiovascular risk (goal attainment rate = 75.1%, 51.7%, and 28.6% for low-, moderate- and high-risk categories, respectively). Of patients not achieving NCEP ATP III LDL-C goals (n = 885), 85.4% had no therapy modification. Goal was achieved after therapy modification in 36% (dose titration) and 42% (switchers); high-risk patients goal attainment rates were 23% and 38%, respectively. Limitations: Limitations of the study include the observational design, use of an administrative claims database to assess cardiovascular risk, relatively short follow-up time (slightly more than 1 year) and the lack of assessment of adherence to therapy. CONCLUSIONS: This study found that the majority of patients initiated on generic simvastatin stayed on their initial starting dose regardless of NCEP ATP III goal attainment status. The findings of low rates of therapy modification irrespective of baseline CV risk and associated low rates of goal attainment, especially in high risk patients treated with simvastatin, indicate an opportunity to encourage clinical decision making based on the needs of the individual patient. PMID: 19916706 [PubMed - indexed for MEDLINE]
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