25 research outputs found
Determination of spray drift and buffer zones in 3D crops using the ISO standard and new LiDAR methodologies
Spray drift generated in the application of plant protection products in tree crops (3D crops) is a major source of environmental contamination, with repercussions for human health and the environment. Spray drift contamination acquires greater relevance in the EU Southern Zone due to the crops structure and the weather conditions. Hence, there is a need to evaluate spray drift when treating the most representative 3D crops in this area. For this purpose, 4 spray drift tests, measuring airborne and sedimenting spray drift in accordance with ISO 22866:2005, were carried out for 4 different crops (peach, citrus, apple and grape) in orchards of the EU Southern Zone, using an air-blast sprayer equipped with standard (STN) and spray drift reduction (DRN) nozzle types. A further 3 tests were carried out to test a new methodology for the evaluation of spray drift in real field conditions using a LiDAR system, in which the spray drift generated by different sprayer and nozzle types was contrasted. The airborne spray drift potential reduction (DPRV) values, obtained following the ISO 22866:2005, were higher than those for sedimenting spray drift potential reduction (DPRH) (63.82%-94.42% vs. 39.75%-69.28%, respectively). For each crop and nozzle type combination, a sedimenting spray drift model was also developed and used to determine buffer zone width. The highest buffer width reduction (STN vs DRN) was obtained in peach (˃75%), while in grape, citrus and apple only 50% was reached. These results can be used as the starting point to determine buffer zone width in the countries of the EU Southern Zone depending on different environmental threshold values. Tests carried out using LiDAR system demonstrated high capacity and efficiency of this system and this newly defined methodology, allowing sprayer and nozzle types in real field conditions to be differentiated and classified.This work was partly funded by the Secretaria d'Universitats i Recerca del Departament d'Empresa i Coneixement de la Generalitat de Catalunya, the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund (ERDF) under grants 2017 SGR 646, AGL2007-66093-C04-03, AGL2010-22304-04-C03-03, and AGL2013-48297-C2-2-R. The authors also wish to thank Mr. Antonio Checa (Randex Iberica, S.L.) for giving us free Albuz nozzles for the spray tests. Universitat de Lleida is also thanked for Mr. X. Torrent's pre-doctoral fellowship
Vascular aging in long-term survivors of testicular cancer more than 20 years after treatment with cisplatin-based chemotherapy
Background: Late effects of cisplatin-based chemotherapy in testicular cancer survivors (TCS) include cardiovascular morbidity, but little data is available beyond 20 years. The objective was to assess vascular damage in very long-term TCS. Methods: TCS (treated with chemotherapy or orchiectomy only) and age-matched healthy controls were invited. Study assessment included vascular stiffness with ultrasound measurement of carotid-femoral pulse wave velocity (cf-PWV). Results: We included 127 TCS consisting of a chemotherapy group (70 patients) and an orchiectomy group (57 patients) along with 70 controls. Median follow-up was 28 years (range: 20–42). The cf-PWV (m/s) was higher in TCS than in controls (geometrical mean 8.05 (SD 1.23) vs. 7.60 (SD 1.21), p = 0.04). The cf-PWV was higher in the chemotherapy group than in the orchiectomy group (geometrical mean 8.39 (SD 1.22) vs. 7.61 (SD 1.21), p < 0.01). In the chemotherapy group cf-PWV increased more rapidly as a function of age compared to controls (regression coefficient b 7.59 × 10−3 vs. 4.04 × 10−3; p = 0.03). Conclusion: Very long-term TCS treated with cisplatin-based chemotherapy show increased vascular damage compatible with “accelerated vascular aging” and continue to be at risk for cardiovascular morbidity, thus supporting the need for intensive cardiovascular risk management. Clinical trial registration: The clinical trial registration number is NCT02572934
Inhibition of DHCR24 activates LXRα to ameliorate hepatic steatosis and inflammation
Liver X receptor (LXR) agonism has theoretical potential for treating NAFLD/NASH, but synthetic agonists induce hyperlipidemia in preclinical models. Desmosterol, which is converted by Δ24-dehydrocholesterol reductase (DHCR24) into cholesterol, is a potent endogenous LXR agonist with anti-inflammatory properties. We aimed to investigate the effects of DHCR24 inhibition on NAFLD/NASH development. Here, by using APOE*3-Leiden. CETP mice, a well-established translational model that develops diet-induced human-like NAFLD/NASH characteristics, we report that SH42, a published DHCR24 inhibitor, markedly increases desmosterol levels in liver and plasma, reduces hepatic lipid content and the steatosis score, and decreases plasma fatty acid and cholesteryl ester concentrations. Flow cytometry showed that SH42 decreases liver inflammation by preventing Kupffer cell activation and monocyte infiltration. LXRα deficiency completely abolishes these beneficial effects of SH42. Together, the inhibition of DHCR24 by SH42 prevents diet-induced hepatic steatosis and inflammation in a strictly LXRα-dependent manner without causing hyperlipidemia. Finally, we also showed that SH42 treatment decreased liver collagen content and plasma alanine transaminase levels in an established NAFLD model. In conclusion, we anticipate that pharmacological DHCR24 inhibition may represent a novel therapeutic strategy for treatment of NAFLD/NASH.</p
Pesticide Exposure of Residents Living Close to Agricultural Fields in the Netherlands:Protocol for an Observational Study
Background: Application of pesticides in the vicinity of homes has caused concern regarding possible health effects in residents living nearby. However, the high spatiotemporal variation of pesticide levels and lack of knowledge regarding the contribution of exposure routes greatly complicates exposure assessment approaches. Objective: The objective of this paper was to describe the study protocol of a large exposure survey in the Netherlands assessing pesticide exposure of residents living close ( Methods: We performed an observational study involving residents living in the vicinity of agricultural fields and residents living more than 500 m away from any agricultural fields (control subjects). Residential exposures were measured both during a pesticide use period after a specific application and during the nonuse period for 7 and 2 days, respectively. We collected environmental samples (outdoor and indoor air, dust, and garden and field soils) and personal samples (urine and hand wipes). We also collected data on spraying applications as well as on home characteristics, participants' demographics, and food habits via questionnaires and diaries. Environmental samples were analyzed for 46 prioritized pesticides. Urine samples were analyzed for biomarkers of a subset of 5 pesticides. Alongside the field study, and by taking spray events and environmental data into account, we developed a modeling framework to estimate environmental exposure of residents to pesticides. Results: Our study was conducted between 2016 and 2019. We assessed 96 homes and 192 participants, including 7 growers and 28 control subjects. We followed 14 pesticide applications, applying 20 active ingredients. We collected 4416 samples: 1018 air, 445 dust (224 vacuumed floor, 221 doormat), 265 soil (238 garden, 27 fields), 2485 urine, 112 hand wipes, and 91 tank mixtures. Conclusions: To our knowledge, this is the first study on residents' exposure to pesticides addressing all major nondietary exposure sources and routes (air, soil, dust). Our protocol provides insights on used sampling techniques, the wealth of data collected, developed methods, modeling framework, and lessons learned. Resources and data are open for future collaborations on this important topic
Quaking promotes monocyte differentiation into pro-atherogenic macrophages by controlling pre-mRNA splicing and gene expression
A hallmark of inflammatory diseases is the excessive recruitment and influx of monocytes to sites of tissue damage and their ensuing differentiation into macrophages. Numerous stimuli are known to induce transcriptional changes associated with macrophage phenotype, but posttranscriptional control of human macrophage differentiation is less well understood. Here we show that expression levels of the RNA-binding protein Quaking (QKI) are low in monocytes and early human atherosclerotic lesions, but are abundant in macrophages of advanced plaques. Depletion of QKI protein impairs monocyte adhesion, migration, differentiation into macrophages and foam cell formation in vitro and in vivo. RNA-seq and microarray analysis of human monocyte and macrophage transcriptomes, including those of a unique QKI haploinsufficient patient, reveal striking changes in QKI-dependent messenger RNA levels and splicing of RNA transcripts. The biological importance of these transcripts and requirement for QKI during differentiation illustrates a central role for QKI in posttranscriptionally guiding macrophage identity and function.No sponso
An empirical model based on phenological growth stage for predicting pesticide spray drift in pome fruit orchards
An innovative spray drift model is developed to describe downwind deposits of pesticides applied in an orchard of pome fruit trees (apple, pear). The empirical model is based on 20 years of experimental data of downwind deposits of spray drift for conventional cross-flow spray applications. The model reveals the major factors affecting downwind deposits: wind speed, wind direction, air temperature and density of the tree canopy. Modelling the canopy density of the trees as a continuous function of time is an innovative approach. Canopy density is uniquely related to growth stage through the phenological BBCH index. Observed effects of the mentioned factors on deposits are discussed. Model results and measured deposits show a correlation coefficient of 87%, while covering a range of almost three orders of magnitude. The model forms the basis for risk assessment for exposure of aquatic organisms concerning all edge-of-field water bodies in the Netherlands. Implementation of drift mitigation techniques is straightforward when appropriate experimental data on reductions of downwind spray deposits is available
Bolus administration of obestatin does not change glucose and insulin levels neither in the systemic nor in the portal circulation of the rat
Obestatin is a second peptide derived from the preproghrelin polypeptide. it was originally thought to have anorexigenic effects, thereby functioning as an antagonist of ghrelin. However, this has been a subject of debate ever since. Since acylated ghrelin strongly induces insulin resistance, it could be hypothesized that obestatin plays a role in glucose homeostasis as well. In the present study we evaluated the effect of obestatin on glucose and insulin metabolism in the systemic and portal circulation. Obestatin 200 nmol/kg was administered systemically as a single intravenous bolus injection to fasted pentobarbital anesthetized adult male Wistar rats. Up to 50 min after administration, blood samples were taken to measure glucose and insulin concentrations, both in the portal and in the systemic circulation. The effect of obestatin was evaluated in fasted and in glucose-stimulated conditions (IVGTT) and compared to control groups treated with saline or IVGTT, respectively. Intravenous administration of obestatin did not have any effect on glucose and insulin concentrations, neither systemic nor portal, when compared to the control groups. Only the glucose peak 1 min after administration of IVGTT was slightly higher in the obestatin treated rats: 605.8 +/- 106.3% vs. 522.2 +/- 47.1% in the portal circulation, respectively (NS), and 800.7 +/- 78.7% vs. 549.6 +/- 37.0% in the systemic circulation, respectively (P < 0.02), but it can be debated whether this has any clinical relevance. In the present study, we demonstrated that intravenously administered obestatin does not influence glucose and insulin concentrations, neither in the portal nor in the systemic circulation. (c) 2008 Elsevier Inc. All rights reserved
Field-crop-sprayer potential drift measured using test bench : Effects of boom height and nozzle type
Because of variations in environmental conditions, spray-drift field measurements following ISO 22866:2005 involve complicated and time-consuming experiments often with low repeatability. Therefore, simple, repeatable, and precise alternative drift assessment methods that are complementary to the official standards are required. One of the alternatives is the use of a drift test bench for field crop sprayers. Previous studies have demonstrated that the drift test bench can be considered an adequate complement to existing standard protocols for field drift measurements. In this study, in order to further improve the methodology and to evaluate the possibility of classifying different field-crop-sprayer settings according to drift risk using a test bench, a series of tests were performed in a test hall. A conventional mounted Delvano HD3 crop sprayer (Delvano, Kuurne, Belgium) equipped with an 800-l spray tank and a 15-m-wide stainless steel spray boom was used. Eight different sprayer setups were tested, involving three nozzle types (TeeJet XR 110 04, Agrotop TDXL 110 04 and Micron Micromax 3) and three boom heights (0.30, 0.50, and 0.70 m). For the drift classification, the reference sprayer drift behaviour was defined as that obtained using conventional flat fan TeeJet XR 110 04 nozzles operated at 0.30 MPa and at a boom height of 0.50 m. The different sprayer setups were successfully assigned to different drift reduction classes, and the results underlined the effects of nozzle type and boom height on the potential drift. The feasibility of the test-bench methodology for classifying field-crop-sprayer drift according to ISO 22369-1:2006 was demonstrated