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Sensitive Populations (sensitive + population)
Selected AbstractsUsing the Triad Approach to expedite the acquisition of an Abbott district school siteREMEDIATION, Issue 2 2004Fred Ellerbusch The Triad Approach was field-tested to determine if characterization objectives could be met for a brownfields property that had been identified as a future elementary school site. The new school is in response to a New Jersey Supreme Court ruling (the Abbott decision) that directed the state of New Jersey to fund school construction in poorer districts to expand physical facilities to relieve overcrowding. The Triad Approach is promoted by the United States Environmental Protection Agency as a process that has the potential to improve the timeliness and efficiency of site characterization, and the New Jersey Department of Environmental Protection (NJDEP) recently issued a policy statement supporting its potential. Aggressive school construction deadlines are contingent on property acquisitions that are relatively faster than the traditional investigatory process. In addition, given the future sensitive population, the investigations must be thorough. This case study is among the first studies to document the use of the Triad Approach for a future school site. The Triad Approach was used to define site conditions for six areas of concern in a two-month time frame (from the start of the planning process to completed investigation). © 2004 Wiley Periodicals, Inc. [source] Phase II study of daily oral perifosine in patients with advanced soft tissue sarcoma,CANCER, Issue 10 2006Howard H. Bailey MD Abstract BACKGROUND. A multicenter Phase II study was performed to evaluate the clinical activity of an initial loading (150 mg every 6 hours × 4 doses) dose followed by continuous daily oral dosing (100 mg/day) of perifosine in patients with advanced soft tissue sarcomas (STSs). METHODS. Patients with measurable metastatic STS received perifosine as first-, second-, or third-line treatment and underwent disease assessment every 8 weeks until disease progression, excessive toxicity, or patient refusal. RESULTS. Twenty-three patients received 66 cycles (1 cycle = 4 weeks) of perifosine. One partial response of 9 months duration was observed. The overall 3 and 6 month progression-free survival was 22% and 9%. NCI CTC (v2.0) Grade 1 to 2 gastrointestinal toxicity or fatigue were the most common (>50% of subjects) toxicities observed. The steady-state plasma perifosine levels (Css) were similar to prior experience (mean 6 ,g/mL). Patients with Css levels >6 ,g/mL appeared more likely to remain on study past 2 months than those with levels <6 ,g/mL. CONCLUSIONS. Despite not achieving the primary objective of ,40% 6-month progression-free survival rate, optimism remains for this agent in STS patients. Prolonged responses in heavily pretreated STS patients continue to be observed with perifosine treatment. Continued assessment of perifosine in STS appears warranted, with special attention to specific histologies or tumor characteristics that might identify a more sensitive population and achieving perifosine Css levels >6 ,g/mL. Cancer 2006 © 2006 American Cancer Society. [source] Evidence of pesticide resistance in medium-sized mammalian pests: a case study with 1080 poison and Australian rabbitsJOURNAL OF APPLIED ECOLOGY, Issue 4 2002Laurie E. Twigg Summary 1Toxicant-resistance is a potential, or very real, problem with many pest-control programmes world-wide. However, apart from rodents, pesticide-resistance has not been well documented in vertebrates. We assessed the potential impact of developing resistance to 1080 in rabbit populations with differing levels of historical exposure to 1080-baiting programmes in south-western Australia. 2The sensitivity to 1080 of three out of the four populations of rabbits Oryctolagus cuniculus examined had decreased significantly since Australian rabbits were last tested over 25 years ago. The lethal dose50 (LD50) values for these populations, as determined from formal toxicity trials, ranged from 0·744 to 1·019 mg pure 1080 kg,1, and were significantly greater (P < 0·05) than the previously reported values for Australian rabbits (LD50 range 0·34,0·46 mg pure 1080 kg,1). The LD50 value for the fourth population (0·584 mg pure 1080 kg,1), which has had the least exposure to 1080, did not differ from that reported previously (P > 0·05). 3The lethal dose99 (LD99) values for the four rabbit populations tested ranged from 1·181 to 1·666 mg pure 1080 kg,1, and suggested that, theoretically, all rabbits should be killed during routine baiting campaigns provided that there is no loss of active ingredient from the bait. In reality, the efficacy of 1080 poison bait laid in trails for controlling free-ranging rabbits was reduced in those populations where rabbits had decreased sensitivity to 1080. Mean reductions in rabbit numbers 7,9 days after trail baiting of resistant and sensitive populations ranged from 51·2% to 65·2%, and from 76·4% to 76·5%, respectively. 4These findings suggest that genetic resistance to 1080 is developing in at least some populations of Australian rabbits. This has world-wide implications for agricultural protection and wildlife conservation programmes that rely on a 1080-baiting strategy for reducing the impact of vertebrate pests. [source] Selection favours low hsp70 levels in chronically metal-stressed soil arthropodsJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2000KÖhler Thirty-eight populations of woodlice (Oniscus asellus, Porcellio scaber) and millipedes (Julus scandinavius) from 28 differently metal-polluted field sites were analysed for their 70-kDa stress protein (hsp70) level. Although ANOVA revealed significant dependence of the hsp70 level on the concentrations of water-soluble lead, cadmium and zinc and the soil pH, each of these parameters accounted for at most 18% of the intersite variability of the stress protein level only. A multivariate model based on multiple regression analysis explained more than 96% of hsp70 variance and revealed both the pollution history of a site (strong metal contamination for more than 70 years) and invertebrate species identity to act as the most important parameters. The model accounted for the observation that most of the populations from long-term polluted sites exhibited comparatively low stress protein levels in response to their own (contaminated) habitats. In contrast, isopods (O. asellus) from a control site were not able to maintain a low hsp70 level when they were exposed to either an artificial metal cocktail or soil taken from one of the contaminated field sites. They did not acclimatize to the exposure conditions within 3 months. We propose that selection of insensitive phenotypes in long-term polluted soils has taken place so as to minimize the stress protein level which, in turn, is indicative of high intracellular protein integrity. Long-term selection for a high hsp70 level to compensate for adverse metal impact was not observed, which suggests that such a strategy may trade off against other fitness consequences. In this context, insensitivity to metal stress involved increased selectivity in food choice and reduced variability in stress response. Multiple regression models showed species-specificity in those abiotic factors which determined (1) high hsp70 levels in sensitive populations as well as (2) low hsp70 levels in insensitive ones. Therefore, abiotic factors can be assigned to act as the main components of selection: lead and cadmium for J. scandinavius and O. asellus, zinc for P. scaber. [source] Monitoring of resistance to spirodiclofen and five other acaricides in Panonychus citri collected from Chinese citrus orchardsPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 9 2010Jinfeng Hu Abstract BACKGROUND: Citrus red mite, Panonychus citri (McGregor), is one of the most important pesticide-resistant pests in China. In order better to understand its resistance status, six populations of the mite were collected from Chinese citrus orchards for monitoring of resistance to spirodiclofen and another five acaricides. RESULTS: All the samples collected in the field in 2006 were susceptible to spirodiclofen. However, the LC50 values in populations sampled in 2009 ranged from 3.29 to 418.24 mg L,1 spirodiclofen, a 127-fold difference between the least and most sensitive populations. Compared with a susceptible strain, 50-fold and 90.8-fold resistance to spirodiclofen was detected in populations sampled from Pinghe and Fuzhou in 2009, as well as cross-resistance to spirotetramat. The LC50 values for abamectin, fenpropathrin, hexythiazox and pyridaben in the collected samples ranged from 0.041 to 3.52 mg L,1, from 23.91 to 696.16 mg L,1, from 13.94 to 334.19 mg L,1 and from 48.90 to 609.91 mg L,1 respectively. CONCLUSION: Great variations in resistance to the tested acaricides were observed among the sampled populations. The Pinghe population developed resistance to all the acaricides tested. The Jianning population was susceptible to most acaricides tested, except pyridaben. Resistance management strategies were conducted on the basis of these observations. Copyright © 2010 Society of Chemical Industry [source] Graminicide resistance in a blackgrass (Alopecurus myosuroides) population correlates with insensitivity of acetyl-CoA carboxylasePLANT CELL & ENVIRONMENT, Issue 1 2004L. J. PRICE ABSTRACT The appearance of biotypes of the annual grass weed black-grass (Alopecurus myosuroides L. Huds), which are resistant to certain graminicides, is the most significant example of acquired resistance to herbicides seen so far in European agriculture. An investigation was perfomed into the basis of the specific cross-resistance to cyclohexanedione (CHD) and aryloxyphenoxypropionoic acid (AOPP) herbicides in the ,Notts A1' population of A. myosuroides, which survived treatment of fields with recommended rates of AOPP herbicides. In comparison with the wild-type ,Rothamsted' population, the resistant biotype showed over 100-fold resistance to these herbicides in a hydroponic growth system. Biosynthesis of fatty acids and activity of crude extracts of acetyl-CoA carboxylase (ACCase) were commensurately less sensitive to these herbicides in Notts A1 compared with the Rothamsted biotype. These data are consistent with the hypothesis that the highly resistant population has arisen through selection of a mutant ACCase which is much less sensitive to the AOPP and CHD graminicides. Rapidly growing cell suspension cultures established from the Notts A1 population also showed high resistance indices for CHD or AOPP herbicides compared with cultures from the Rothamsted biotype. Fatty acid biosynthesis and ACCase activity in the cell suspensions were similarly sensitive towards the graminicides to those in the foliar tissue counterparts of the resistant and sensitive populations. Moreover, purification of the main (chloroplast) isoform of acetyl-CoA carboxylase showed that this enzyme from the Notts A1 population was over 200-fold less sensitive towards the AOPP herbicide, quizalofop, than the equivalent isoform from the Rothamsted population. These data again fully supported the proposal that resistance in the Notts biotype is due to an insensitive acetyl-CoA carboxylase isoform. Overall, cell suspensions were also demonstrated to be excellent tools for further investigation of the molecular basis of the high level herbicide resistance which is prone to occur in A. myosuroides. [source] Limitations to CO2 assimilation in ozone-exposed leaves of Plantago majorNEW PHYTOLOGIST, Issue 1 2002Y. Zheng Summary ,,The potential limitations on net leaf carbon assimilation imposed by stomatal conductance, carboxylation velocity, capacity for ribulose 1,5-bisphosphate regeneration and triose phosphate ultilization rate were derived from steady-state gas exchange measurements made over the life-span of two leaves on plants of an ,O3 -sensitive' population of Plantago major grown at contrasting atmospheric O3 concentrations. ,,Parallel measurements of chlorophyll fluorescence were used to monitor changes in the quantum efficiency of PSII photochemistry, and in vitro measurements of Rubisco activity were made to corroborate modelled gas exchange data. ,,Data indicated that a loss of Rubisco was predominantly responsible for the decline in CO2 assimilation observed in O3 -treated leaves. The quantum efficiency of PSII was unchanged by O3 exposure. ,,Stomatal aperture declined in parallel with CO2 assimilation in O3 -treated plants, but this did not account for the observed decline in photosynthesis. Findings suggested that O3 -induced shifts in stomatal conductance result from ,direct' effects on the stomatal complex as well as ,indirect effects' mediated through changes in intercellular CO2 concentration. Leaves on the same plant exposed to equivalent levels of O3 showed striking differences in their response to the pollutant. [source] Upper susceptibility threshold limits with confidence intervals: a method to identify normal and abnormal population values for laboratory toxicological parameters, based on acetylcholinesterase activities in sea licePEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 3 2006Anders Fallang Abstract The interpretation and importance of comparing field values of susceptibility to pesticides with a laboratory reference strain that might bear little resemblance to the actual situation in the field are problematic and a continuing subject of debate. In this paper a procedure for defining a ,normal sensitive' population from a field study of 383 individuals to provide a basis for analysing and interpreting in vitro results is described and examined. Instead of using only the 95th percentile, the upper and lower confidence limits for the 95th percentile were also compared to select the best estimation of the limit for the normal material. A field population constrained by the upper confidence limit for the 95th percentile provides appropriate descriptions of the normal material in this study. This approach should prove useful in studies of pesticide resistance in field populations. Copyright © 2006 Society of Chemical Industry [source] | ||||||||||