An educational intervention on the risk perception of pesticides exposure and organophosphate metabolites urinary concentrations in rural school children in Maule Region, Chile.

BACKGROUND: Organophosphate (OP) pesticides can be hazardous to human health if not applied with appropriate precautions. There is evidence in the Maule region of Chile that rural schoolchildren are exposed to OP pesticides. OBJECTIVE: To evaluate the effectiveness of an educational intervention on OP exposure and understanding of pesticides and their hazards (risk perception) in two school communities in the Maule Region of Chile during 2016. METHOD: We conducted a quasi-experimental study about the effects on OP pesticide exposure of a community outreach and education program (COEP) administered in four 2-h sessions that's included hands-on activities among 48 schoolchildren from two rural schools. The intervention was directed to groups of parents and school-children separately, and aimed to educate them about the risks of exposure to pesticides and their effects on health. We measured 3,5,6-trichloro-2-pyridinol (TCPy), 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMPY), malathion dicarboxylic acid (MDA), p-nitrophenol (PNP), specific urinary metabolites of the OP pesticides chlorpyrifos, diazinon, malathion and parathion, respectively, as well as the non-specific diethylakylphosphates (DEAPs) and dimethylalkylphosphates (DMAPs) in 192 urine samples of schoolchildren collected before and after the intervention. The risk perception of school children and their parents was also assessed through a questionnaire before and after the intervention. Generalized Estimated Equations were used to account for each child's repeated measures during four sessions, two in September 2016 (pre-intervention) and two in November 2016 (post-intervention). RESULTS: The intervention level had significant effect on the risk perception of adults and children, which increased after the intervention. However, the intervention was not associated with reduced of urinary metabolites levels, with no significant differences between the pre and post measures. The detection frequencies were 1.1% (MDA), 71.4% (TCPy), 43.3% (IMPY), 98.96% (PNP), and 100% (DEAPs and DMAPs). Higher DEAPs urine concentrations were associated with eating more fruit at school (p = 0.03), a younger age (p = 0.03), and being male (p = 0.01). DMAPs showed no associations with potential predictor variables (e.g. OPs applied at home, fruit consumption at school, among others). Higher TCPy was associated with attending a school closer to farms (p = 0.04) and living in a home closer to farm fields (p = 0.01); higher PNP was marginally associated with children younger age (p = 0.035). CONCLUSION: Environmental exposure to OP pesticides was unchanged even after behavior changes. It is possible that a longer time period is needed to observe changes in both behavior and urinary metabolites. The levels of DEP and DMP metabolites found here are above the reference population of the US, and our findings indicate exposure to a wide variety of OP pesticides. Given that individual-level interventions were not associated with lower exposures, efforts to reduce exposure must occur upstream and require stricter regulation and control of pesticide use by government agencies.

Assessing biomarkers and neuropsychological outcomes in rural populations exposed to organophosphate pesticides in Chile--study design and protocol.

BACKGROUND: Health effects of pesticides are easily diagnosed when acute poisonings occurs, nevertheless, consequences from chronic exposure can only be observed when neuropsychiatric, neurodegenerative or oncologic pathologies appear. Therefore, early monitoring of this type of exposure is especially relevant to avoid the consequences of pathologies previously described; especially concerning workers exposed to pesticides on the job. For acute organophosphate pesticides (OPP) exposure, two biomarkers have been validated: plasma cholinesterase (ChE) and acetylcholinesterase (AChE) from erythrocytes. These enzymes become inhibited when people are exposed to high doses of organophosphate pesticides, along with clear signs and symptoms of acute poisoning; therefore, they do not serve to identify risk from chronic exposure. This study aims to assess a novel biomarker that could reflect neuropsychological deterioration associated with long-term exposure to organophosphate pesticides via the enzyme acylpeptide-hydrolase (ACPH), which has been recently identified as a direct target of action for some organophosphate compounds. METHODS/DESIGN: Three population groups were recruited during three years (2011-2013): Group I having no exposure to pesticides, which included people living in Chilean coastal areas far from farms (external control); Group II included those individuals living within the rural and farming area (internal control) but not occupationally exposed to pesticides; and Group III living in rural areas, employed in agricultural labour and having had direct contact with pesticides for more than five years. Blood samples to assess biomarkers were taken and neuropsychological evaluations carried out seasonally; in three time frames for the occupationally exposed group (before, during and after fumigation period); in two time frames for internal control group (before and during fumigation), and only once for the external controls. Neuropsychological evaluations considered cognitive functions, affectivity and psychomotor activity. The biomarkers measured included ChE, AChE and ACPH. Statistical analysis and mathematical modelling used both laboratory results and neuropsychological testing outcomes in order to assess whether ACPH would be acceptable as biomarker for chronic exposure to OPP. DISCUSSION: This study protocol has been implemented successfully during the time frames mentioned above for seasons 2011, 2012 and 2013-2014.

Chromium-induced genotoxicity and interference in human lymphoblastoid cell (TK6) repair processes.

Two model chromium (Cr) compounds, one hexavalent (sodium chromate) and one trivalent (chromium chloride), were investigated in a human lymphoblastoid cell line (TK6) to increase our knowledge regarding Cr-induced genotoxicity mechanisms. Both selected compounds were genotoxic using the comet assay, although the percentage of DNA in tail obtained after treatment with Cr(VI) was significantly higher than that obtained with Cr(III), at the higher concentrations tested. To determine the nature of the induced damage, enzymes recognizing oxidized bases were used. Treatments with formamidopyrimidine (FPG) and endonuclease III (EndoIII) displayed a greater degree of DNA damage, indicating that the induction of oxidized bases accounts for an important proportion of the damage induced by Cr compounds. In addition, the kinetic repair studies showed that generated DNA damage is removed in approximately 8 h, with the damage induced by Cr(III) being removed/repaired more rapidly than damage produced by Cr(VI). To detect Cr interferences with the repair process, a post-treatment was applied after exposure to 2 Gy gamma radiation. Post-treatment significantly delayed the repair kinetics of DNA damage induced by radiation. This interference effect induced by Cr(VI) was more pronounced. In conclusion, evidence indicates that a high proportion of the Cr-induced DNA damage is correlated with oxidative damage, and that both Cr compounds interfere with repair mechanisms involved in repair of DNA damage induced by gamma radiation.

Psychometric Validation of a Questionnaire to Assess Perception and Knowledge About Exposure to Pesticides in Rural Schoolchildren of Maule, Chile.

Exposure to pesticides during infancy is associated with numerous adverse health outcomes. The assessment of knowledge and perception of pesticides exposure and risk among children has not been thoroughly studied. The aim of the study was to evaluate the reliability and validity of a questionnaire that measures the knowledge and perception of exposure to organophosphate pesticides among rural schoolchildren. The questionnaire was administered to 151 schoolchildren between 9 and 13years from four Chilean rural schools. An internal consistency analysis of the ordinal alpha coefficient and a polychoric factor analysis for categorical data were used. The results show that the ordinal alpha was 0.95. Polychoric matrices of rotated components show the 17 questions summarized pesticide knowledge in five factors extracted after promax rotation. This factorial model explains 56.3% of the variance. The questions were grouped as follows: knowledge about pesticides (Factor 1); knowledge of health effects related to pesticides exposure (Factor 2); pesticide exposure through the growing of fruits and vegetables (Factor 3); perception and action against pesticides exposure at school (Factor 4); and perception and action against pesticides exposure at home (Factor 5). The questionnaire provides a useful tool for examining pesticide exposure in agricultural regions, allowing younger community members to participate.

Oxidative DNA damage in chronic renal failure patients.

BACKGROUND: Chronic renal failure (CRF) patients present a high incidence of cardiovascular pathologies and cancer. This has been attributed to the existence of genomic instability in these patients, and consequently they should present elevated levels of genetic damage. METHODS: To determine the background levels of genetic damage and its specific levels of oxidative damage, a large population of 253 CRF patients (77 in dialysis) was analysed using the comet assay. The percentage of DNA in the tail was used as a measure of basal genetic damage. In addition, the use of endo III and FPG enzymes allowed us to determine the levels of specific oxidative damage in DNA bases. RESULTS: This is the first study that uses endo III and FPG enzymes to measure oxidative damage in CRF patients. Overall genetic damage, as well as specific oxidative damage, was higher in dialysis patients than in the CRF patients with different stages of uraemic state; genetic damage increased when serum creatinine levels increased. Genomic damage in dialysis patients decreased in those patients submitted to dialysis for a long time. CONCLUSIONS: Genetic damage increases when renal function decreases, being maximum in haemodialysis patients. Although part of the observed damage can be attributed to the uraemic state itself, other individual genetic factors can influence a state of genomic instability responsible for the observed genomic damage.

[Egg morphology of seven noctuid species (Lepidoptera: Noctuidae) from Chilean and updated key to their identification]. / Morfologia de huevos de siete especies de n6ctuidos de Chile (Lepidoptera: Noctuidae) y clave actualizada para su identificación.

Eggs from seven Noctuid moth species, Eriopyga perfusca (Hampson), Magnagrotis oorti (Koehler), Pseudoleucania brosii (Koehler), Scania simillima (Koehler). Scriptania americana (Blanchard), Scriptania leucofasciata Rodriguez, were collected at La Mina, 925 msnm, (35 degrees 21' S; 71 degrees 41' W) and Paso Internacional Pchucnche (35 degrees 57' S: 70 degrees 23' W), 2560 msnm, Chile. The Scanning Electron Microscope showed that egg morphology allows identification to species level. This is particularly useful in agricultural pest control, and morphological differences are used in this report to present an updated taxonomic key to the Chilean Noctuidae.

Dynamic responses of Xenopus retinal ganglion cell axon growth cones to netrin-1 as they innervate their in vivo target.

Netrin-1 influences retinal ganglion cell (RGC) axon pathfinding and also participates in the branching and synaptic differentiation of mature RGC axons at their target. To investigate whether netrin also serves as an early target recognition signal in the brain, we examined the dynamic behavior of Xenopus RGC axons soon after they innervate the optic tectum. Time-lapse confocal microscopy imaging of RGC axons expressing enhanced yellow fluorescent protein demonstrated that netrin-1 is involved in early axon branching, as recombinant netrin-1 halted further advancement of growth cones into the tectum and induced back branching. RGC growth cones exhibited differential responses to netrin-1 that depended on the degree of differentiation of the axon and the developmental stage of the tadpole. Netrin-1 decreased the total number of branches on newly arrived RGC growth cones at the target, but increased the dynamic branching of more mature arbors at the later developmental stage. To further explore the response of axonal growth cones to netrin, Xenopus RGC axons were followed in culture by time-lapse imaging. Exposure to netrin-1 rapidly increased the forward advancement of the axon and decreased the size and expanse of the growth cone, while also inducing back branching. Taken together, the differential in vivo and in vitro responses to netrin-1 suggest that netrin alone is not sufficient to induce the cessation of growth cone advancement in the absence of a target but can independently modulate axon branching. Collectively, our findings reveal a novel role for netrin on RGC axon branch initiation as growth cones innervate their target.

Morfología de huevos de siete especies de nóctuidos de Chile (Lepidoptera: Noctuidae)y clave actualizada para su identificación / Egg morphology of seven noctuid species (Lepidoptera: Noctuidae) from Chilean and updated key to their identification

Eggs from seven Noctuid moth species, Eriopyga perfusca (Hampson), Magnagrotis oorti (Koehler), Pseudoleucania brosii (Koehler), Scania simillima (Koehler), Scriptania americana (Blanchard), Scriptania leucofasciata Rodríguez, were collected at La Mina, 925 msnm, (35º 21’ S; 71º 41’ W) and Paso Internacional Pehuenche (35º 57’ S; 70º 23’ W), 2560 msnm, Chile. The Scanning Electron Microscope showed that egg morphology allows identification to species level. This is particularly useful in agricultural pest control, and morphological differences are used in this report to present an updated taxonomic key to the Chilean Noctuidae

Se obtuvieron huevos de siete especies de nóctuidos chilenos: Eriopyga perfusca Hampson, Scriptania americana (Blanchard), Scriptania leucofasciata Rodríguez, Magnagrotis oorti (Koehler), Pseudoleucania brossi (Koehler) y Scania simillima (Koehler) de La Mina, VII Región, 925 m, (35º 21’ S, 71º 41’ W) y Paso Internacional Pehuenche, 2560 m, (35º 57’ S, 70º23’ W). Se fotografiaron entre cuatro y nueve huevos de cada especie con Microscopia Electrónica de Barrido para analizar las variaciones entre las celdas primarias y secundarias. Los resultados morfológicos fueron utilizados para actualizar la clave taxonómica de las especies de nóctuidos chilenos